Field of the Invention

This invention relates to a system for controlling the state of a flow control valve for controlling the flow of temperature control fluid within an internal combustion gasoline or diesel engine equipped with a radiator.

Background of the Invention

Page 111 of the Goodheart-Wύlcox automotive encyclopedia, The Goodheart-Willcox Company, Inc., South Holland, Illinois, 1979 describes that as fuel is burned in an internal combustion engine, about one-third of the heat energy in the fuel is converted to power. Another third goes out the exhaust pipe unused, and the remaining third must be handled by a cooling system. This third is often underestimated and even less understood.

Most internal combustion engines employ a pressurized cooling system to dissipate the heat energy generated by the combustion process. The cooling system circulates water or liquid coolant through a water jacket which surrounds certain parts of the engine (e.g., block, cylinder, cylinder head, pistons). The heat energy is transferred from the engine parts to the coolant in the water jacket. In hot ambient air temperature environments, or when the engine is working hard, the transferred heat energy will be so great that it will cause the liquid coolant to boil (i.e., vaporize) and destroy the cooling system. To prevent this from happening, the hot coolant is circulated through a radiator

well before it reaches its boiling point. The radiator dissipates enough of the heat energy to the surrounding air to maintain the coolant in the liquid state.

In cold ambient air temperature environments, especially below zero degrees Fahrenheit (-17.8°C), or when a cold engine is started, the coolant rarely becomes hot enough to boil. Thus, the coolant does not need to flow through the radiator. Nor is it desirable to dissipate the heat energy in the coolant in such environments since internal combustion engines operate most efficiently and pollute the least when they are running relatively hot. A cold running engine will have significantly greater sliding friction between the pistons and respective cylinder walls than a hot running engine because oil viscosity decreases with temperature. A cold running engine will also have less complete combustion in the engine combustion chamber and will build up sludge more rapidly than a hot running engine. All of these factors lower fuel economy and increase levels of hydrocarbon exhaust emissions. To avoid running the coolant through the radiator, coolant systems employ a thermostat. The thermostat operates as a one-way valve, blocking or allowing flow to the radiator. Figs. 31-33 (described below) and Fig. 2 of U.S. Patent No. 4,545,333 show typical prior art thermostat controlled coolant systems. Most prior art coolant systems employ wax pellet type or bimetallic coil type thermostats. These thermostats are self-contained devices which open and close according to precalibrated temperature values.

Coolant systems must perform a plurality of functions, in addition to cooling the engine parts. In cold weather, the cooling system must deliver hot coolant to heat exchangers associated with the heating and defrosting system so that the heater and defroster can deliver warm air to the passenger compartment and windows. The coolant system must also deliver hot coolant to the intake manifold to heat incoming air destined for combustion, especially in cold ambient air temperature environments, or when a cold engine is started. Ideally, the coolant system should also reduce its volume and speed of flow when the engine parts are cold so as to allow the engine to reach an optimum

hot operating temperature. Since one or both of the intake manifold and heater need hot coolant in cold ambient air temperatures and/or during engine start-up, it is not practical to completely shut off the coolant flow through the engine block. Practical design constraints limit the ability of the coolant system to adapt to a wide range of operating environments. For example, the heat removing capacity is limited by the size of the radiator and the volume and speed of coolant flow. The state of the self-contained prior art wax pellet type or bimetallic coil type thermostats is controlled solely by coolant temperature. Thus, other factors such as ambient air temperature cannot be taken into account when setting the state of such thermostats.

Numerous proposals have been set forth in the prior art to more carefully tailor the coolant system to the needs of the vehicle and to improve upon the relatively inflexible prior art thermostats. U.S. Patent No. 4,484,541 discloses a vacuum operated diaphragm type flow control valve which replaces a prior art thermostat valve in an engine cooling system. When the coolant temperature is in a predetermined range, the state of the diaphragm valve is controlled in response to the intake manifold vacuum. This allows the engine coolant system to respond more closely to the actual load on the engine. U.S. Patent No. 4,484,541 also discloses in Fig. 4 a system for blocking all coolant flow through a bypass passage when the diaphragm valve allows coolant flow into the radiator. In this manner, all of the coolant circulates through the radiator (i.e. , none is diverted through the bypass passage), thereby shortening the cooling time.

U.S. Patent No. 4,399,775 discloses a vacuum operated diaphragm valve for opening and closing a bypass for bypassing a wax pellet type thermostat valve. During light engine load operation, the diaphragm valve closes the bypass so that coolant flow to the radiator is controlled by the wax pellet type thermostat. During heavy engine load operation, the diaphragm

valve opens the bypass, thereby removing the thermostat from the coolant flow path. Bypassing the thermostat increases the volume of cooling water flowing to the radiator, thereby increasing the thermal efficiency of the engine.

U.S. Patent No. 4,399,776 discloses a solenoid actuated flow control valve for preventing coolant from circulating in the engine body in cold engine operation, thereby accelerating engine warm-up. This patent also employs a conventional thermostat valve.

U.S. Patent No. 4,545,333 discloses a vacuum actuated diaphragm flow control valve for replacing a conventional thermostat valve. The flow control valve is computer controlled according to sensed engine parameters.

U.S. Patent No. 4,369,738 discloses a radiator flow regulation valve and a block transfer flow regulation valve which replace the function of the prior art thermostat valve. Both of those valves receive electrical control signals from a controller. The valves may be either vacuum actuated diaphragm valves or may be directly actuated by linear motors, solenoids or the like. In one embodiment of the invention disclosed in this patent, the controller varies the opening amount of the radiator flow regulation valve in accordance with a block output fluid temperature. U.S. Patent No. 5,121,714 discloses a system for directing coolant into the engine in two different streams when the oil temperature is above a predetermined value. One stream flows through the cylinder head and the other stream flows through the cylinder block. When the oil temperature is below the predetermined value, a flow control valve closes off the stream through the cylinder block. Although this patent suggests that the flow control valve can be hydraulically actuated, no specific examples are disclosed. The flow control valve is connected to an electronic control unit (ECU). This patent describes that the ECU receives signals from an outside air temperature sensor, an intake air temperature sensor, an intake pipe vacuum pressure sensor, a vehicle velocity sensor, an engine rotation sensor and an oil temperature sensor.

The ECU calculates the best operating conditions of the engine cooling system and sends control signals to the flow control valve and to other engine cooling system components.

U.S. Patent No.5,121,714 employs a typical prior art thermostat valve 108 for directing the cooling fluid through a radiator when its temperature is above a preselected value. This patent also describes that the thermostat valve can be replaced by an electrical-control valve, although no specific examples are disclosed.

U.S. Patent No. 4,744,336 discloses a solenoid actuated piston type flow control valve for infinitely varying coolant flow into a servo controlled valve. The solenoids receive pulse signals from an electronic control unit (ECU). The ECU receives inputs from sensors measuring ambient temperature, engine input and output coolant temperature, combustion temperature, manifold pressure and heater temperature. One prior art method for tailoring the cooling needs of an engine to the actual engine operating conditions is to selectively cool different portions of an engine block by directing coolant through different cooling jackets (i.e. , multiple circuit cooling systems). Typically, one cooling jacket is associated with the engine cylinder head and another cooling jacket is associated with the cylinder block.

For example, U.S. Patent No. 4,539,942 employs a single cooling fluid pump and a plurality of flow control valves to selectively direct the coolant through the respective portions of the engine block. U.S. Patent No. 4,423,705 shows in Figs. 4 and 5 a system which employs a single water pump and a flow divider valve for directing cooling water to head and block portions of the engine.

Other prior art systems employ two separate water pumps, one for each jacket. Examples of these systems are given in U.S. Patent No. 4,423,705 (see Fig. 1), U.S. Patent No.4,726,324, U.S. Patent No.4,726,325 and U.S. Patent No. 4,369,738.

Still other prior art systems employ a single water pump and single water jacket, and vary the flow rate of the coolant by varying the speed of the water pump.

U.S. Patent No. 5,121,714 discloses a water pump which is driven by an oil hydraulic motor. The oil hydraulic motor is connected to an oil hydraulic pump which is driven by the engine through a clutch. An electronic control unit (ECU) varies the discharge volume of the water pump according to selected engine parameters.

U.S. Patent No. 4,079,715 discloses an electromagnetic clutch for disengaging a water pump from its drive means during engine start-up or when the engine coolant temperature is below a predetermined level.

Published application nos. JP 55-35167 and JP 53-136144

(described in column 1, lines 30-62 of U.S. Patent No. 4,423,705) disclose clutches associated with the driving mechanism of a water pump so that the pump can be stopped under cold engine operation or when the cooling water temperature is below a predetermined value.

Despite the large number of ideas proposed to improve the performance of engine cooling systems, there is still a need for cooling system components and techniques which allow the system to more effectively match its performance to the instantaneous needs of the engine, while still meeting the plurality of other functions noted above which are demanded of the cooling system. There is especially a need for a system and technique for controlling the state of one or more flow control valves in engine cooling systems in accordance with predetermined engine and ambient temperature conditions . The present invention fills that need.

Summary of the Invention

The present invention provides a temperature control system in a liquid cooled internal combustion engine equipped with a radiator. The

system comprises a flow control valve, first and second sensors and an engine computer. The flow control valve controls flow of a temperature control fluid through a passageway. The flow control valve has a first state for preventing or inhibiting the flow and a second state for allowing the flow. The first sensor detects the temperature of the temperature control fluid and the second sensor detects ambient air temperature. The engine computer receives signals from the first and second sensors and compares the signals to a set of predetermined values which define a curve. Preferably a portion of the curve has a non zero slope. The engine computer determines a desired state of the valve based on the comparison and produces control signals for actuating the valve into the desired state.

A method for controlling the flow of temperature control fluid through an internal combustion engine is also disclosed. The method includes the steps of receiving an ambient temperature signal and a temperature control signal, comparing the received signals to a set of predetermined values for determining a desired state of a flow control valve and and actuating the flow control valve into the desired state.

Brief Description of the Drawings For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

Fig. 1 is a top plan view of one preferred form of a hydraulically operated electronic engine temperature control valve for controlling the flow of temperature control fluid in an engine.

Fig. 2 is a sectional side view of the valve in Fig. 1, taken along line 2-2 in Fig. 1.

Fig. 3 is a different sectional side view of the valve in Fig. 1, taken along line 3-3 in Fig. 1.

Fig. 4 is yet another sectional side view of the valve in Fig. 1 , taken along line 4-4 in Fig. 1.

Fig. 5 is a horizontal sectional view of the valve in Figs. 1 and 2, taken along line 5-5 in Fig. 2. Fig. 6 is a diagrammatic view of the valve in Fig. 1 connected to parts of an engine.

Fig. 7 is sectional side view of a preferred form of a multi¬ function valve which controls the flow of temperature control fluid to plural parts of an engine, shown in a first position. Fig. 8 is sectional side view of the multi-function valve of Fig.

7, shown in a second position.

Fig. 9 is a sectional side view of a piston type hydraulically operated electronic engine temperature control valve for controlling the flow of temperature control fluid in an engine. Fig. 10 is an end view of the valve in Fig. 9.

Fig. 11 is a sectional side view of another embodiment of a piston type hydraulically operated electronic engine temperature control valve for controlling the flow of temperature control fluid in an engine.

Fig. 12 is an end view of the valve in Fig. 11. Fig. 13A is an enlarged view of a stationary rod seal employed in the embodiment of the invention shown in Fig. 7.

Fig. 13B is an enlarged view of a gasket seal employed in the embodiment of the invention shown in Fig. 7.

Fig. 14 is a diagrammatic illustration of a temperature control system of an internal combustion engine employing the multi-function valve of Figs. 7 and 8.

Fig. 15 is an exploded view of a portion of the valve in Fig. 2 showing a preferred embodiment of a diaphragm and how it attaches to the valve housing.

Figs. 16A and 16B are sectional views of a hydraulic fluid injector suitable for controlling the state or position of the valves in the invention.

Fig. 16C is a sectional view of an alternative type of hydraulic fluid injector suitable for controlling the state or position of the valves in the invention.

Fig. 17 is a block diagram circuit of the connections to and from an engine computer for controlling the state or position of the valves in the invention. Fig. 18 is a diagrammatic sectional view of an engine block showing a temperature control fluid passageway through the engine block to an oil pan, for use with the valve shown in Fig. 7.

Figs. 19 and 20 are graphs showing the state of a valve in the invention at selected temperature control fluid and ambient air temperatures. Fig. 21 is a graph showing the state of prior art wax pellet type or bimetallic coil type thermostats at the same selected temperature control fluid and ambient air temperatures of temperatures as in Figs. 19 and 20.

Figs. 22A and 22B are graphs showing the state of a plurality of valves in the invention at selected temperature control fluid and ambient air temperatures.

Fig. 23 is a graph showing the actual temperature of the temperature control fluid when controlling the plurality of valves referred to in

Fig. 22A according to the Fig. 22A scheme, compared to the actual temperature of engine coolant when a prior art thermostat is employed and controlled according to the Fig. 21 scheme.

Fig. 24 is a diagrammatic sectional view of an engine block showing restrictor/shutoff flow control valves in accordance with the invention.

Fig. 25 is a sectional side view of the restrictor/shutoff valve mounted to a fluid passageway.

Fig. 26 is an exploded view of the parts of the restrictor/shutoff valve in Fig. 25.

Fig. 27 is a sectional view of the restrictor/shutoff valve in Fig. 25, taken along line 27-27 in Fig. 25. Fig. 28 is a sectional view of the restrictor/shutoff valve in Fig.

25, taken along line 28-28 in Fig. 25.

Fig. 29 is a sectional side view of an alternative embodiment of the restrictor/shutoff valve in its environment for simultaneously controlling fluid flow in two different passageways. Fig. 30 is a diagrammatic sectional view of the water jacket in an engine block showing how the restrictor/shutoff valve controls fluid flow in interior and exterior passageways of the water jacket.

Fig. 31 is a diagrammatic view of the coolant circulation flow path through a prior art engine when a thermostat is closed. Fig. 32 is an idealized diagrammatic view of the coolant circulation flow path through a prior art engine when a thermostat is open.

Fig. 33 is an actual diagrammatic view of the coolant circulation flow path through a prior art engine when a thermostat is open.

Fig. 34 is a sectional side view of a preferred form of a multi- function valve which controls the flow of temperature control fluid to plural parts of an engine.

Fig. 35 A is a flow chart for a first embodiment of a novel system for dithering the hydraulic injectors.

Fig. 35B is a flow chart for a second embodiment of a novel system for dithering the hydraulic injectors.

Fig. 35C is a flow chart for a third embodiment of a novel system for dithering the hydraulic injectors.

Description of the Preferred Embodiment

While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Certain terminology is used herein for convenience only and is not be taken as a limitation on the invention. Particularly, words such as "upper," "lower," "left," "right," "horizontal," "vertical," "upward, " and "downward" merely describe the configuration shown in the figures. Indeed, the valves and related components may be oriented in any direction.

Apparatus depicting the preferred embodiments of the novel electronic engine temperature control valve are illustrated in the drawings.

Fig. 1 shows a top plan view of electronic engine temperature control valve 10 (hereafter, "EETC valve 10") as it would appear attached to an engine temperature control fluid passageway 12. (Only a portion of the passageway 12 is visible in this view.) The EETC valve 10 is attached to the passageway 12 by mounting bolts 14. The EETC valve 10 includes two major subcomponents, a valve mechanism 16 and a pair of solenoid actuated hydraulic fluid injectors 18 and 20. The injector 18 is a fluid inlet valve and the injector 20 is a fluid outlet valve. In effect, the injectors 18, 20 are one-way flow through valves. The view in Fig. 1 shows valve housing sub-parts including housing 22 of the valve mechanism 16 and housings 24 and 26 of the respective hydraulic fluid injectors 18 and 20. The EETC valve 10 also includes fluid pressure sensor 28 mounted to the valve housing through insert 30. In the preferred embodiment, the insert 30 is a brass fitting.

Also visible in Fig. 1 are electrical terminals 32, 34, and fluid inlet and outlet tubes 36, 38, associated with respective fluid injectors 18 and 20. These tubes are attached to respective solid tubes which feed into the valve housing through inserts 30. Those inserts 30 are not visible in this view. However, the insert 30 associated with the inlet tube 36 is visible in Fig. 3.

The inlet tube 36 is connected to a source of pressurized hydraulic fluid, such as engine lubrication oil. The outlet tube 38 is connected to a low pressure reservoir of the hydraulic fluid, such as an engine lubrication oil pan. Each of the electrical terminals 32, 34 are connected at one end to a solenoid inside of its respective fluid injector (not shown) and at the other end to a computerized engine electronic control unit (ECU) (not shown).

Fig. 2 shows a sectional side view of one version of the EETC valve 10, taken along line 2-2 in Fig. 1. In this version, the EETC valve 10 is a hydraulically actuated diaphragm valve 40. The diaphragm valve 40 reciprocates within the valve housing 22 along axis A between a first and second state or position. The solid lines in Fig. 2 shows the valve 40 in the first position which is associated with a valve "closed" state. Fig. 2 also shows the valve's second position in phantom which is associated with a valve "open" state. In the first "closed" position, the valve 40 prevents flow of temperature control fluid (hereafter, "TCF") through passageway opening 42. In the second "open" position, the valve 40 allows fluid flow through the opening 42. The opening 42 leads to the engine radiator (not shown). Also visible in Fig. 2 is the electrical terminal 34 and the outlet tube 38 associated with the solenoid 20, the fluid pressure sensor 28, and one of the mounting bolts 14. The temperature control fluid (TCF) referred to herein is typically known in the art as "coolant. " Coolant is a substance, ordinarily fluid, used for cooling any part of a reactor in which heat is generated. However, as will be described below, the TCF not only removes heat energy from engine components but is also employed in certain embodiments to deliver heat energy to certain engine components. Thus, the TCF is more than merely a coolant. Likewise, while the prior art referenced herein relates to engine cooling systems, the invention herein employs its unique valve(s) in an engine temperature control system, providing both cooling and heating functions to engine components.

Turning again to Fig. 2, the valve 40 reciprocates within the valve mechanism housing 22. The housing 22 is constructed of body 44 and cover 46, held together by band clamp or crimp 48. The body 44 includes a generally horizontal dividing wall 50 which divides the body 44 into upper compartment 52 and lower compartment 54. (It should be recognized that the dividing wall 50 is a generally cylindrical disk in three dimensions.) The center of the dividing disk or wall 50 has a circular bore to allow passage of a reciprocating valve shaft or rod therethrough, as described below. A cylindrical collar 56 extends verticaUy upward and downward from the inner edge of the dividing wall 50, thereby coinciding with the outer circumference of the circular bore. The collar 56 is integral with the dividing wall 50. The lower end of the lower compartment 54 leads to the opening 42.

As noted above, the valve 40 reciprocates between a first "closed" position wherein the valve 40 prevents flow of TCF through passageway opening 42 and a second "open" position wherein the valve 40 allows fluid flow through the opening 42. When the valve 40 is "closed," the water pump circulates the TCF only through the engine block water jacket. If the heater or defroster is in operation, the fluid is also circulated through a heat exchanger for the passenger compartment heater, typically a heater core. When the valve 40 is "open, " most of the TCF flows through the radiator before it is circulated through the engine block water jacket and the heater's heat exchanger.

Thus, in the embodiment of the invention shown in Fig. 2, the valve 40 functions in a manner similar to the prior art wax pellet thermostat. However, unlike the fixed temperature wax pellet thermostat, the valve 40 is electronically controlled and thus can be opened and closed according to a computer controUed signal taUored to specific engine operating conditions and ambient environmental conditions.

The diaphragm valve 40 includes upper chamber 58, diaphragm 60, plate 62, lower chamber 64, shaft or rod 66, valve member 68 and biasing

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spring 70. The diaphragm 60, plate 62 and spring 70 are disposed in the housing body's upper compartment 52. The diaphragm 60 separates the housing body's upper compartment 52 into the upper and lower chambers 58, 64. The spring 70 is seated on one side against a lower surface of the plate 62 and on the other side against an upper surface of the housing body's dividing wall 50. The rod 66 is also seated on one side against the lower surface of the plate 62 and extends through the housing body's upper and lower compartments 52, 54. The diaphragm 60 is mechanically linked to the valve member 68 through the plate 62 and the rod 66. The position of the diaphragm 60 is thus communicated through the plate 62 and the rod 66 to the valve member 68, thereby causing the valve member 68 to reciprocate between the first and second positions, shown in solid and in phantom, respectively.

The lower chamber portion of the body 44 includes air bleed opening 72 therethrough for removing and reintroducing air into the lower chamber 64 as the diaphragm valve 40 is moved between its first and second positions. Radial O-ring 74 prevents the hydraulic fluid from leaking out of passage 76.

The valve 40 also includes a gasket seal 78 around the periphery of the opening 42 to allow the valve member 68 to close off flow through the opening 42 when the valve 40 is in the first position. In the preferred embodiment of the invention, the gasket seal 78 also functions as the valve seat for the valve member 68. The gasket seal 78 is generally square in vertical cross-section, although other shapes are contemplated by the invention. One preferred type of gasket seal material is Viton , manufactured by E.I. Du Pont De Nemours & Co., Wilmington, DE. An O-ring 80 is disposed within the outer circumference of the rod 80 to prevent TCF in the lower compartment 54 from leaking into the valve's lower chamber 64.

In the preferred embodiment of the invention, the diaphragm 60 possesses special characteristics to allow it to more easily withstand very high

pressures. Details of the diaphragm 60 are more fully discussed with respect to Fig. 15.

The diaphragm valve upper chamber 58 is in fluid communication with hydraulic fluid passageway 82 through opening 84 therebetween. The fluid passageway 82 is in fluid communication with the outlet of the hydraulic fluid injector 18 and the inlet of the hydraulic fluid injector 20 through the passage 76, as best shown in Fig. 4. The fluid passageway is also in fluid communication with the fluid pressure sensor 28 to allow the pressure in the passageway to be monitored for controlling the valve state. Diaphragm valves of the size suitable for installation in an engine fluid passageway can typically withstand pressures in the range of 200 psi (1378 kPa). The diaphragm strength is typically the first component to fail due to excessive high pressure. Pressure monitoring helps to ensure that pressures do not exceed those which the valve components can safely handle. In the preferred embodiment of the invention, the diaphragm includes certain features to allow it to better withstand a high pressure environment. Fig. 15 shows a preferred diaphragm and an exploded view of the preferred manner in which the diaphragm is mounted in the diaphragm valve mechanism housing to achieve the best results under high pressure. Unlike prior art diaphragm valves, such as disclosed in U.S.

Patent No. 4,484,541, which are actuated and deactuated by applying and removing a vacuum to and from an upper chamber, the diaphragm valve 40 disclosed herein is actuated by pressurized and depressurizing the upper chamber 58 with hydraulic fluid. A hydraulic fluid system has numerous advantages over a vacuum actuated system including less sensitivity to temperature extremes, and increased accuracy, durabUity and reliability.

In operation, the valve 40 functions as follows. When the engine is operating and it is desired to open the valve 40, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 18 to open the injector's valve. Simultaneously, the ECU sends a control signal to the solenoid of the

hydraulic fluid injector 20 to close that injector's valve, if it is not already closed. Pressurized hydraulic fluid from the fluid inlet tube 36 flows through the fluid injector 18, the hydraulic fluid passageway 82, the opening 84 and into the valve upper chamber 58, where it pushes against the diaphragm 60 and plate 62. When the fluid pressure against the diaphragm 60 and plate 62 exceeds the opposing force of the biasing spring 70, the diaphragm 60 moves downward, thereby causing the valve member 68 to move downward. The upper chamber 58 expands as the diaphragm 60 and plate 62 moves downward. As the upper chamber 58 fills with fluid, the pressure in the chamber rises. When the pressure sensor 28 detects that the fluid pressure has reached a predetermined level, it causes the ECU to start a timer which runs for a predetermined period of time. After that time has expired, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 18 to close the injector's valve. The hydraulic fluid in the upper chamber 58 thus remains trapped therein. The predetermined pressure level and time period are empirically determined so as to allow the valve member 68 to reach its open or second position. To avoid excessively activating the injector's solenoids, the open injector valve should be closed as soon as the diaphragm valve 40 has reached the desired state. Also, a diaphragm valve 40 is selected which will always open under less pressure than exists in the hydraulic fluid system that the inlet fluid injector 18 is attached to. To remove air trapped in the upper chamber 58 and/or connected passageways, the ECU can be programmed to open the valve of the outlet fluid injector 20 for a short period of time (e.g., one second). This is similar to the technique for bleeding air from a vehicle's hydraulic braking system.

If hydraulic fluid leaks out of the upper chamber 58, the pressure sensor 28 wUl immediately sense this condition. The ECU responds by again sending a control signal to the solenoid of the hydraulic fluid injector 18 to open the injector's valve. When the pressure sensor 28 detects that the fluid pressure has again reached the predetermined level, it causes the ECU to start a timer

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which runs again for a predetermined period of time. After that time has expired, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 18 to close the injector's valve.

The process of opening the EETC valve is automatically delayed by the ECU during engine start-up until the source of the hydraulic fluid pressure reaches it normal operating level. In one embodiment of the invention which employs engine lubrication oil as the hydraulic fluid, the delay period is about two or three seconds to allow for lubrication of all critical engine components. When it is desired to close the valve 40, the above steps are reversed. That is, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 18 to close the injector's valve, if it is not already closed. Simultaneously, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 20 to open that injector's valve. The pressurized hydraulic fluid inside the upper chamber 58 flows out of the upper chamber 58 through the opening 84, into the hydraulic fluid passageway 82, through the open valve of the hydraulic fluid injector 20 and into the fluid outlet tube 38. The fluid outlet tube 38 connects to a reservoir (not shown) of hydraulic fluid. As the hydraulic fluid empties out of the upper chamber 58, biasing spring 70 pushes the diaphragm 60 and plate 62 upward, thereby causing the valve member 68 to move upward until the valve 40 becomes closed. When the pressure sensor 28 detects that the upper chamber 58 is no longer pressurized, it causes the ECU to send a control signal to the solenoid of the hydraulic fluid injector 20 to close that injector's valve. The vehicle's engine does not need to be operating to close the valve 40. Thus, during a "hot engine off soak" (i.e., the time period subsequent to shutting off a hot engine), the valve 40 stays open since the hydraulic fluid remains trapped in the upper chamber 58. This function mimics prior art cooling systems which maintain an open path to the radiator until the thermostat's wax pellet rehardens. After the engine has cooled down, the ECU

(which is powered from the vehicle's battery) causes the valve 40 to close, as described above.

Fig. 3 shows a different sectional side view of the diaphragm version of the EETC valve 10, taken along line 3-3 in Fig. 1. This view more clearly shows the entire path of the TCF from a passageway leading from the engine block water jacket, through the valve 40 and to the radiator. As noted above, if the valve 40 is closed, the TCF circulates directly back into the engine block water jacket, without being diverted into the radiator.

Fig. 3 also shows the inlet hydraulic fluid injector 18 and the fluid inlet tube 36 leading thereto, along with the insert 30 associated therewith. As noted above, the insert 30 is preferably a brass fitting. The passageway 82 from the outlet of the injector's valve to the upper chamber 58 is not visible in this view but is clearly shown in Fig. 4. The fluid connection or path between the fluid inlet tube 36 and the injector 18 is also not visible in this view but is understandable with respect to Fig. 6.

Fig. 4 shows yet another sectional side view of the diaphragm version of the EETC valve 10, taken along line 3-3 in Fig. 1. This view shows fluid passageway 86 from the outlet of the hydraulic fluid injector 18 to the passage 76 leading to the diaphragm upper chamber 58, and from the upper chamber 58 to the passage 76 leading from the hydraulic fluid injector 20. Again, the fluid connections or paths between the fluid inlet and outlet tubes 36, 38 and the respective injectors 18, 20 are also not visible in this view but are understandable with respect to Fig. 6.

Fig. 5 is a horizontal sectional view of the EETC valve 10 in Figs. 1 and 2, taken along line 5-5 in Fig. 2. This view shows more of the internal structure of the valve parts.

Fig. 6 shows diagrammatically the preferred embodiment of how the EETC valve 10 connects to a source of hydraulic fluid. In this embodiment of the invention, the source of hydraulic fluid is engine lubrication oil. In Fig. 6, a portion of engine block 88 is cut away to show engine lubrication oil pump

90 and engine lubrication oil reservoir 92 in oil pan 94. As is well known in the art, outlet 96 of the oil pump 90 feeds oil to practically all of the engine moving parts under pump pressure through distributing headers (not shown). To provide a source of pressurized hydraulic fluid to the inlet fluid injector 18, the fluid inlet tube 36 is connected to the oil pump outlet 96. An optional replaceable filter 98 may be placed in the pressurized oil line to ensure that the oil flowing to the valve 10 does not clog the injectors. To provide a return path for the hydraulic fluid exiting from the outlet fluid injector 20, the fluid outlet tube 38 is connected to the oil reservoir 92 in the oil pan 94. Figs. 7 and 8 show another preferred form of an EETC valve 100 which simultaneously controls the flow of TCF to plural parts of an engine. In a first embodiment, the EETC valve 100 controls fluid flow to the radiator and the oil pan. When the EETC valve 100 is in a first position, flow to the radiator is blocked and flow to the oil pan is permitted. When the EETC valve 100 is in a second position, flow to the radiator is permitted and flow to the oil pan is blocked. Fig. 7 shows the EETC valve 100 in the first position, whereas Fig. 8 shows the valve in the second position.

In a second embodiment, the EETC valve 100 controls fluid flow to the radiator, oil pan and a portion of the engine block water jacket. In the depicted embodiment, that portion of the water jacket comprises the portion around the intake manifold. When the EETC valve 100 is in a first position, flow to the radiator is blocked and flow to the oil pan and the intake manifold is permitted. When the EETC valve 100 is in a second position, flow to the radiator is permitted, flow to the oil pan is blocked, and flow to the intake manifold is either restricted or blocked. Again, Fig. 7 shows the EETC valve

100 in the first position, whereas Fig. 8 shows the valve in the second position.

The EETC valve 100 employs a diaphragm valve 102. The sectional view in Fig. 7 is slightly different than the section taken of EETC valve 10 through line 2-2 in Fig. 1 so as to show the TCF passage through the EETC valve 100. It should be noted that a top plan view of the EETC valve

100 will appear identical to EETC valve 10 shown in Fig. 1. Furthermore, the valve parts and housing of EETC valve 100 differ only slightly from the EETC valve 10. One difference between EETC valve 10 and EETC valve 100 lies in the shape of the housing body's dividing wall and collar attached thereto. In the embodiment of the invention shown in Fig. 7, dividing wall 104 has a unique shape to allow it to accept a unique stationary rod seal 106. The seal 106 performs a function similar to the O-ring 80 shown in Fig. 2. That is, the seal 106 prevents TCF in the valve's lower compartment 108 from leaking into the valve's lower chamber 142. The EETC valve 100 is siπύlar to the EETC valve 10 in that its housing 112 includes a body 114 and a cover 116, held together by band clamp or crimp 118.

The dividing wall 104 in Fig. 7 is defined by three integrally formed portions, a downwardly tapered portion 120 attached at one end to a sidewall of housing 112, a generally vertical portion 122 attached at one end to the other end of the tapered portion 120, and a generally horizontal portion 124 attached at one end to the other end of the generally vertical portion 122. The center of the dividing wall 104 has a circular bore to allow passage of reciprocating valve rod 126 therethrough, in the same manner as the valve rod in EETC valve 10. Thus, the generally horizontal portion 124 does not extend completely across the radius of the housing 112. A cylindrical collar 128 extends vertically upward from the other end of the horizontal portion 124 (i.e., from the inner edge of the dividing wall 104), thereby coinciding with the outer circumference of the circular bore. Unlike the collar 56 in diaphragm valve 40, the collar 128 does not extend downward from the dividing wall 104. Instead, the dividing wall 104 includes an integrally formed extension flange 130 which extends perpendicularly downward by a short distance from a center region of the horizontal portion 124. The unique stationary rod seal 106 is attached to a lower surface of the dividing wall 104 as best shown in Fig. 13A.

Fig. 13 A shows an enlarged view of the circled dashed region in Fig. 7 associated with the stationary rod seal 106. Reciprocating valve rod 126

moves along axis A adjacent to the inner sidewall of the dividing wall's horizontal portion 124. The extension flange 130 includes a curved outer wall surface 132 and a generally planar inner wall surface 134. The extension flange 130 extends downward from the horizontal portion by a distance of about d _t . A cylindrical seal 136 having a generally rectangular vertical cross-section is fit into the space between the extension flange's inner wall surface 134 and the outer circumferential wall of the rod 126 (or the outer circumferential wall of the dividing wall's bore, if the rod 126 is not yet inserted into place). The seal 136 has a vertical width slightly less than d, so that the seal 136 lies approximately flush with a horizontal plane formed by the lower surface of the extension flange 130. The seal 136 also has a circular impression therein for accepting O-ring 138. Retention cup 140 is attached to the lower surface of the extension flange 130 and the seal 136. The outer edge of the cup 140 wraps around the curved outer wall surface 132 of the extension flange 130. One suitable material for the retention cup 140 is a brass cup crimped over the curved outer wall surface 132. A suitable material for the seal 136 is a standard POLYPAK retention seal manufactured by Parker-Hannifin Corp. , Cleveland, OH. A suitable rod 126 will have an outer diameter of about 3/8 inch (0.95 cm). A stationary rod seal 106 constructed with those materials will withstand TCF pressures of at least 50 psi (345 kPa).

The stationary rod seal 106 inhibits debris which becomes lodged on the lower portion of the rod 126 from traveling up into the valve's lower chamber 142 when the rod 126 moves from the second position shown in Fig. 8 to the first position shown in Fig. 7. The stationary rod seal 106 effectively acts as a wiper, dislodging any such debris from the rod 126 and depositing in the valve's lower compartment 108 where it can be carried away by the TCF. The dividing wall 104/stationary rod seal 106 feature in EETC valve 100 can replace the dividing wall/O-ring sealing structure in EETC valve 10.

Turning again to Fig. 7, the diaphragm valve 102 includes a reinforced gasket seal 144. The details of the gasket seal 144 are shown more clearly in Fig. 13B. The gasket seal 144 also functions as the valve seat for valve member 146. Fig. 13B shows an enlarged view of the circled dashed region in

Fig. 7 associated with the gasket seal 144. The gasket seal 144 provides two functions. First, it functions as a sealing seat for the valve member 146. Second, it prevents the TCF from flowing into the valve's lower compartment 108 when the EETC valve 100 is in the first position. The gasket seal 144 includes an elastomer material 148 having a cut-out 150. A washer 152, preferably of stainless steel, is snapped into the cut-out 150. The washer 152 limits the travel of the valve member 146 by strengthening and supporting the gasket seal 144, thereby increasing the integrity of the seal 144. If the cut-out 150 and washer 152 were not present, the valve member 146 would be more prone to push through the elastomer material 148 under high pressure conditions. To inhibit this from occurring, the inner diameter of the washer 152 is dimensioned to be smaller than the outer diameter of the bottom of the valve member 146.

The gasket seal 144 is pressed into a cut-out 154 in a wall of TCF passageway 156, although it may also be located in a cut-out of a wall of the valve's lower compartment 108. The cut-out 154 and the washer's cut-out 150 are dimensioned so that an outer diameter portion of the washer 152 recesses in the wall. This arrangement tightly traps the washer 152 into position. As noted above, the first embodiment of the EETC valve 100 controls fluid flow to the radiator and the oU pan. This is accomplished by including an opening 158 in the TCF passageway 156 leading to an additional TCF passageway 160. The passageway opening 158 is positioned within the passageway 156 so that when the valve member 146 is in the first position (as shown in Fig. 7), the valve member 146 does not block the opening 158,

thereby allowing flow of a portion of the fluid therethrough. When the valve member 146 is in the second position (as shown in Fig. 8), the valve member 146 becomes seated against the opening 158, thereby closing the opening 158, and thus preventing flow of any of the fluid therethrough. The diaphragm valve 102 does not need to be modified to provide the additional control function associated with the fluid flow to the oil pan. It is only necessary to position the opening 158 so that the valve member 146 seats over it at the end of its stroke, as shown in Fig. 8.

Fig. 15 shows the preferred diaphragm 102 exploded from the housing body 114 and valve cover 116. The diaphragm 102 is formed from a flexible material which moves between the first position shown in Fig. 7 and the second position shown in Fig. 8 as hydraulic fluid fills into and empties from the diaphragm valve's upper chamber. The diaphragm 102 includes an integrally molded O-ring type flange 110 which extends downward from the outer circumference and seats into groove 162 formed in the upper edge of the body 114. The diaphragm also includes an integrally molded bead 164 on the top side of the flange 110. The preferred material for the diaphragm 102 is an elastomer 166, covered with fabric 168 on its lower surface. One suitable

Φ φ combination of elastomer and fabric is Viton and Nomex , both manufactured by E.I. Du Pont De Nemours & Co. , Wilmington, DE. This type of diaphragm is designed by RPP Corporation, Lawrence, MA.

The size of the diaphragm 102 is determined by the dimensions of the EETC valve 100. In one embodiment of the invention wherein the EETC valve 100 is sized to replace a prior art wax pellet or bimetallic coil type thermostat, a suitable diaphragm 102 will have the following dimensions:

1. end-to-end diameter of about 1.87 inches (4.75 cm);

2. top-to-bottom height of about .55 inches; (1.397 cm)

2. flange diameter and height of about .094 inches (0.239 cm); and 3. bead 164 radius of about .015 inches (0.0381 cm).

A diaphragm 102 sized as such will fit into a cylinder bore having a diameter of about 1.43 inches (3.632 cm) and will accept an upper plate of a piston rod having a diameter of about 1.18 inches (2.997 cm).

Since Fig. 15 shows the preferred embodiment of the housing body/diaphragm valve cover subassembly, it should be understood that the equivalent subassembly in the EETC valve 10 also preferably employs this embodiment. The diaphragm in the EETC valve 10 has an integrally molded O-ring type flange which extends upward from the outer circumference and seats into a groove formed in the lower edge of the valve cover. The diaphragm in the EETC valve 10 is also preferably an elastomer, covered with fabric on its lower surface. The diaphragm in the EETC valve 10 does not include an integrally molded bead on an opposite side of the flange. Accordingly, it is easier and cheaper to manufacture.

The particular features of the diaphragm 102 and the manner in which it is assembled between the housing body 114 and valve cover 116 allows the diaphragm 102 to withstand larger pressures than the diaphragm of the EETC valve 10.

Fig. 14 diagrammatically shows a temperature control system of an internal combustion engine employing the multi-function EETC valve 100 of Figs. 7 and 8, including the first and second embodiments of fluid flow provided by the dual action diaphragm valve 102. The fluid paths to and from the automobile heater are not shown in this simplified diagram.

When the EETC valve 100 is employed in its first embodiment to control fluid flow only to the radiator and the oil pan, the system shown in Fig. 14 function as follows.

When the diaphragm valve 102 is in the second position shown in Fig. 8 (i.e., open to TCF flowing to the radiator, closed to TCF flowing to the oU pan), the TCF enters a TCF jacket 200 formed in a cylinder block. From there, it is supplied to TCF jackets 202 and 204 formed respectively in a cylinder head and an intake manifold. The engine TCF leaving the jackets

200, 202 and 204 flows through the valve 102 and is introduced to radiator 206 through radiator inlet passage 208. The TCF which enters the radiator 206 is cooled during its passage therethrough by air flow from cooling fan 210 located at the rear side of the radiator 206. The cooled TCF is supplied to a TCF pump 212 (e.g., a water pump) through the radiator outlet passage 214. The TCF supplied to the pump 212 is again circulated to the jackets 200, 202 and 204.

When the diaphragm valve 102 is in the first position shown in Fig. 7 (i.e., closed to TCF flowing to the radiator, open to TCF flowing to the oil pan), the TCF which enters the TCF jacket 200 is supplied to the TCF jackets 202 and 204. The engine TCF leaving the jackets 200 and 202 bypasses the radiator 206 through bypass passage 216 and is delivered directly to the pump 212 for recirculation. Since the passageway 160 is now open to fluid flow, a portion of the TCF flows therethrough and into heat exchanger 218 in the oil pan 94. The heat exchanger 218 comprises a U-shaped heat conductive tube 220 which allows heat from the TCF to pass into the oil in the oil pan 94. Other tubing shapes are also suitable. The TCF exiting the heat exchanger 218 flows back into the pump 212 for recirculation.

In cold temperature environments, or when an engine is first warmed up, the engine lubrication oil should be heated to its normal operating temperature as rapidly as possible, and maintained it at that temperature. In prior art engine cooling systems, engine coolant is not employed to assist in this goal. To the contrary, prior art systems work against this goal by immediately circulating coolant through the jacket and removing heat from the engine block, and thus from the engine oU.

This invention helps to achieve that goal by circulating a portion of the TCF through the oU pan 94. Since the diaphragm valve 102 is likely to be in the Fig. 7 first position in cold temperature environments, or when the engine is first warmed up, the oil in the oil pan 94 will receive warm or hot TCF when it needs it the most. The heat energy transferred from the warm or

hot TCF into the oil allows the oil to more quickly reach its ideal operating temperature. In effect, the TCF diverted to the oil pan 94 recaptures some of the parasitic engine heat loss caused by circulation of the TCF.

Furthermore, the inventive system described herein allows the engine oil to capture some of the heat energy in the TCF after the engine is turned off. In contrast, the heat energy in the coolant of prior art cooling systems is wasted by being passed into the environment. Since the valve 102 will always be in the first position after engine cooldown, heat energy can pass by convection through the passageway 160 and into the oil pan 94. If the ambient air temperature is very cold, the valve 102 may even remain in the first position during and after engine operation. Thus, convective heating of the engine oil will continue after the engine is turned off. The mass of hot TCF has the potential to keep the engine oil warm for hours after engine shut-off.

As noted above, the EETC valve 100 operates in a second embodiment wherein it controls fluid flow through the radiator, oil pan and a portion of the engine block water jacket (e.g., the portion around the intake manifold). When the EETC valve 100 is in a first position, flow to the radiator is blocked and flow through the oil pan and through intake manifold is permitted. When the EETC valve 100 is in a second position, flow to the radiator is permitted, flow to the oil pan is blocked, and flow through the intake manifold is either restricted or blocked.

Operation of the second embodiment of the EETC valve 100 is best understood with respect to Figs. 8 and 14. The valve's hydraulic fluid passageway 170 includes opening 172 leading to fluid outlet tube 174 through housing insert 176, preferably a brass fitting. The outlet tube 174 is connected to an intake manifold flow control valve. This valve is not shown in Fig. 8, but is labelled in Fig. 14 as valve 300. The valve 300 controls the flow of fluid through the intake manifold jacket 204 which surrounds the intake manifold (not shown). For the purposes herein, the valve 300 can be any valve which is moved from a first position to a second position by hydraulic fluid pressure

applied to a valve chamber, wherein the first position is associated with unrestricted fluid flow through an associated passageway and the second position is associated with either restricted or blocked flow through the passageway. One example of a valve 300 suitable for this purpose is described in Figs. 24-30 of this disclosure. However, the valve 300 can comprise any type of hydraulically fluid actuated valve such as a piston valve, diaphragm valve or the like.

When it is desired to move the diaphragm valve 102 into the second position shown in Fig. 8, pressurized hydraulic fluid flows through the passageway 170 into upper chamber 178. Simultaneously, a portion of the hydraulic fluid flows through the opening 172, into the fluid outlet tube 174 and into the chamber (not shown) of the intake manifold flow control valve 300. The pressurized fluid in this chamber causes the valve 300 to move from the first position (unrestricted flow) to the second position (restricted or blocked flow).

When it is desired to move the diaphragm valve 102 back into the first position shown in Fig. 7, the hydraulic fluid in the upper chamber 178 flows out through an outlet hydraulic fluid injector in the same manner as described with respect to Figs. 2-5. Likewise, the hydraulic fluid in the chamber of the valve 300 flows back into the EETC valve 100 and out through this outiet hydraulic fluid injector. In this manner, the state of the EETC valve 100 determines the state of the valve 300.

The purpose of this control scheme is to reduce the amount of heat energy flowing through the intake manifold when the engine is hot. In a typical internal combustion engine, the intake manifold has an ideal temperature of about 120 degrees Fahrenheit. In such engines, there is no significant advantage in heating the intake manifold to temperatures higher than about 130 degrees Fahrenheit. In fact, extremely hot intake manifold temperatures reduce combustion efficiency. The volume of air expands as it is heated. As the air volume expands, the number of oxygen molecules per unit volume decreases.

Since combustion requires oxygen, reducing the amount of oxygen molecules in a given volume decreases combustion efficiency. Prior art cooling jackets typically deliver coolant through the intake manifold at all times. When an engine is running hot, the coolant temperature is typically in a range from about 160 (71.1°C) to about 200 (93.3°C) degrees Fahrenheit. Thus, the coolant may be significantly hotter than the ideal temperature of the intake manifold. Nevertheless, the prior art cooling system will continue to deliver hot coolant through the intake manifold, thereby maintaining the intake manifold temperature in an excessively high range. The second embodiment of the invention described herein employs the EETC valve 100 to restrict or block the flow of TCF through the intake manifold, thereby avoiding the unwanted condition described above. When the EETC valve 100 is in the first position shown in Fig. 7, it is likely that the temperature of the TCF is below that which would cause the intake mamfold to exceed its ideal operating temperature. Thus, when the EETC valve 100 is in the first position, flow of TCF through the intake manifold is permitted.

The intake manifold flow control valve scheme can also be employed with the EETC valve 10 shown in Figs. 2-5. This scheme functions with or without the modification to the temperature control fluid passageway 12 for diverting the fluid to the oU pan. In Fig. 14, the valve 300 is shown at the end of the intake manifold jacket 204, thereby "dead heading" the flow of fluid through the jacket 204. "Dead heading" is used herein to describe the state whereby the flow of fluid is blocked but the fluid still remains in the water jacket passage due to the continuous pumping of fluid by the engine's water pump. "Restricting" is used herein to describe the state whereby the flow of fluid is partially blocked but a portion of the fluid still flows in the water jacket passage due to the continuous pumping of fluid by the engine's water pump. Since heat energy is primarily transferred to and from the engine block by the flow of fluid, dead heading the flow wUl have almost the same effect as shutting

off the flow. However, a minimum amount of convective fluid heat flow will still occur between the intake manifold jacket 204 and the cylinder head and block jackets 200 and 202 in this configuration. Alternatively, the valve 300 can be placed in the passageway leading to the beginning of the intake manifold jacket 204 (shown in phantom), thereby preventing both fluid flow through the intake manifold jacket 204 and convective fluid heat flow between the jacket 204 and the jackets 200 and 202.

The configuration in Figs. 7 and 8 wherein the EETC valve 100 controls fluid flow to the radiator, oil pan and a portion of the engine block water jacket (e.g., the portion around the intake manifold) produces a highly effective engine temperature control system in a wide range of ambient temperature conditions, as well as during engine warm up. In cold temperature environments and during warm up, the EETC valve 100 allows flow of the TCF to the oil pan and the intake manifold, thereby causing the engine oil and intake manifold to more rapidly reach their ideal operating temperatures. Once the engine is sufficiently warmed up, or when the engine is operating in very hot ambient air temperatures, the EETC valve 100 shuts off flow of the TCF to both the oil pan and the intake manifold since neither the oil, nor the intake mamfold need additional heat energy under either of those conditions. The EETC valve 100 can also control the flow of the TCF to portions of the engine block water jacket other than the portion around the intake manifold. The valve 300 shown in Fig. 14 can alternatively be placed to block or restrict flow through portions of the cylinder block jacket 200 or the cylinder head jacket 202. In another embodiment, a plurality of water jacket blocking/restricting valves can be simultaneously controlled from the hydraulic fluid system of the diaphragm valve 102. Fig. 14 shows one such additional valve 400 in phantom at the end of the cylinder head jacket 402.

The EETC valve 100 can also be employed to address a design compromise inherent in prior art engine cooling systems employing prior art thermostats. Prior art Figs. 31 and 32 show a simplified diagrammatical

representation of coolant circulation flow paths through such an engine. The coolant temperature is represented by stippling densities, hot coolant having the greatest density and cold coolant having the smallest density. Fig. 31 shows that when thermostat 1200 is closed, the coolant that exits water jacket 1202 flows through orifice 1204, into the intake side of water pump 1206, and then back to the water jacket 1202. Thus, the coolant circulates entirely within the engine water jacket 1202, avoiding radiator 1208. Fig. 32 shows that when the thermostat 1200 is open, all of the coolant circulates through the radiator 1208, into the intake side of the water pump 1206, and then back to the water jacket 1202.

Fig. 32 is an idealized diagram of coolant flow. Since fluid takes the path of least resistance, most of the coolant will flow through the larger opening associated with the thermostat 1200, as opposed to the more restrictive orifice 1204. However, a small amount of coolant still passes through the orifice 1204 and into the intake side of the water pump 1206, as shown in prior art Fig. 33. Since this small amount of coolant is not cooled by the radiator 1208, it raises the overall temperature of the coolant reentering the water jacket to a level higher than is desired.

To minimize this problem, the opening associated with the thermostat 1200 is made as large as possible and the orifice 1204 is made as small as possible. However, if the orifice 1204 is made too small, circulation through the water jacket 1202 wUl be severely restricted when the thermostat 1200 is closed. This may potentially cause premature overheating of portions of the engine block and will reduce the amount of heat energy available for the heater and intake manifold during engine start-up and in cold temperature environments. If the orifice 1204 is made too large, the percentage of coolant flowing therethrough will be large when the thermostat 1200 is open. Accordingly, the average temperature of the coolant returning to the water jacket 1202 will be too hot to properly cool the engine.

Thus, prior art engine cooling systems must always attempt to strike the proper balance between extremes when sizing the orifice 1204, thereby resulting in a compromised, but never idealized, size. In an idealized system, the orifice 1204 is open and large when the thermostat 1200 is closed, and is closed when the thermostat 1200 is open.

Fig. 34 shows how the EETC valve 100 can be employed to create this idealized system. Fig. 34 is similar to Figs. 7 and 8, except that the opening 158 shown in Figs. 7 and 8 is an orifice 1210 and this orifice 1210 is the only fluid flow path for the TCF when the EETC valve 100 is in the first position shown in Fig. 7. That is, there is no alternative path to the water pump when the EETC valve 100 is in the first position. This is in contrast to the system in Fig. 7 wherein a portion of the TCF flows through the opening 158 and into the passageway 160, and the remaining portion of the TCF flows to the water pump. Since the orifice 1204 shown in Figs. 31-33 merely functions as a path for coolant to return to the water pump 1206 for recirculation through the water jacket 1202, the system in Fig. 34 takes advantage of this already existing return path (shown in Fig. 18) to achieve the same function.

The orifice 1210 can be sized as large as allowed by the valve member 146, and thus need not be restricted in size by the constraints described above with respect to the prior art engine cooling systems. The TCF flowing through the orifice 1210 travels through the passageway 160 and follows the same path as shown in Fig. 18. When the EETC valve 100 in the configuration in Fig. 34 is in the second position (not shown, but siπular to Fig. 8), no TCF can flow through the orifice 1210, thereby achieving the idealized "no flow" state unattainable in the prior art system described above.

The EETC valve 100 can also be employed in an anticipatory mode to address one problem in prior art engine cooling systems, specifically, the problem of sudden engine block temperature peaks caused when a turbocharger or supercharger is activated. These sudden peaks, in turn, may

cause a rapid rise in coolant temperature and engine oil temperature to levels which exceed the ideal range. Since prior art cooling systems typically cannot shut off flow of coolant to the intake manifold, the rise in engine block temperature causes even more unnecessary heat energy to flow around the already overheated intake manifold. Furthermore, if the engine is still warming up, the prior art wax pellet type thermostat might not even be open. The thermostat might also be closed even if the coolant temperature has reached the range in which it should open, due to hysteresis associated with melting of the wax. The invention herein can employ the EETC valve 100 to lessen the temperature rise effects of the turbocharger or supercharger. When the turbocharger or supercharger is activated, a signal can be immediately delivered to the EETC valve 100 to cause it to move into its second position, as shown in Fig. 8, if it is already not in that position. This will stop the flow of TCF to the engine oil and through the intake manifold, in anticipation of a rapid temperature rise in the oil and the intake manifold due to the action of the turbocharger or supercharger. Likewise, the flow of TCF through the radiator will lessen any peaking of the engine block temperature. A short time after the turbocharger or supercharger is deactivated, the EETC valve can then be returned to the state dictated by the ECU.

Although the preferred embodiment of the invention employs a diaphragm valve in valves 10 and 100, other types of hydraulically activated chamber-type valves can be employed in place of the diaphragm valve. One particularly suitable type of valve is a piston valve having a piston head which reciprocates within the bore of a piston housing, wherein the piston head includes a piston shaft and a cup.

Figs. 9 and 10 disclose one embodiment of a piston valve and Figs. 11 and 12 disclose another embodiment of a piston valve. Both types of valves provide a fluid flow passageway through at least a portion of the housing when the valve is open and block off the fluid flow passageway through that

portion of the housing when the valve is closed. Both types of valves employ the outer circumferential wall of their piston shafts to block a fluid passageway opening through the housing, thereby preventing fluid flow through any portion of the housing. The valves allow flow of fluid through the portion of the housing by moving the outer circumferential wall of their piston shafts wall away from the opening. The valve embodiment in Figs. 11 and 12 is a flow- through type of valve. That is, when the valve is open, the fluid controlled by the valve flows through the interior of the piston head. In contrast, in the embodiment in Figs. 9 and 10, the fluid does not flow through the piston head. In both of the piston valve embodiments, the piston head is moved from the closed to the open position by the force of hydraulic fluid pressure against a rear surface of the cup, and is moved back to the closed position by the force of a biasing spring, in a manner similar in principle to movement of the diaphragm valves in valves 10 and 100. The hydraulic fluid enters and leaves the piston valve through a pair of hydraulic fluid injectors in the same manner as in the valves 10 and 100.

Fig. 9 shows a sectional side view of EETC valve 500 and Fig. 10 shows a right end view of the EETC valve 500 in Fig. 9. The solid lines in Fig. 9 shows the EETC valve 500 in its first position which is associated with a valve "closed" state. Fig. 9 also shows the valve's second position in phantom which is associated with a valve "open" state. For clarity, Figs. 9 and 10 are described together.

The EETC valve 500 includes valve mechanism casing or housing 502, piston head 504, an inlet hydraulic fluid injector 18 and an outlet hydraulic fluid injector 20. Only the inlet hydraulic fluid injector 18 is visible in Fig. 9, whereas both injectors 18, 20 are visible in Fig. 10. Injector 18 is connected to fluid inlet tube 36 and injector 20 is connected to fluid outlet tube 38, in the same manner as the valves 10 and 100.

The housing 502 is a generally cylindrical solid structure having a bore 506 therethrough. The housing 502 is bolted closed at one end 508 by

cover 510 and open at the other end 512. The housing 502 is defined by five main parts, the cover 510, a first cylindrical portion 514 having an inner diameter of about dj, a second cylindrical portion 516 having an inner diameter of about d ₂ and two barrels 518, 520 extending from the housing 502, each barrel housing one of the fluid injectors 18, 20. Barrel 518 and injector 18 are visible in Fig. 9. Only the barrel 518 is visible in Fig. 9, whereas both barrels 518, 520 are visible in Fig. 10. The diameter d ₂ is larger than d,.

The housing 502 also includes two openings therethrough. A first opening 522 located in a mid-region of the first cylindrical portion 514 allows temperature control fluid (TCF) from passageway 524 to pass therethrough when the first opening 522 is not obstructed by the piston head 504. A second opening (not shown) allows hydraulic fluid to flow into and out of a chamber 526 within the housing's second cylindrical portion 516, to and from the pair of fluid injectors 18, 20. Fluid pressure sensor 550 is in communication with the chamber 526. The sensor 550 is visible in Fig. 10 but is not visible in Fig. 9. This sensor 550 performs the same function as the fluid pressure sensor 28 in the EETC valve 10.

The piston head 504 is a unitary solid structure defined by two main parts, a piston shaft 528 and a piston cup 530 connected to one end of the shaft 528. The other end of the shaft 528 is closed. The piston cup 530 and the left hand portion of the piston shaft 528 reciprocate within the second cylindrical portion 516 of the housing 502. The piston shaft 528 is a preselected length which aUows its outer circumferential wall to block the first opening 522 when the piston head 504 is in the first position and allows its outer circumferential wall to move completely away from the first opening 522 when the piston head 504 is in the second position. The piston shaft 528 has an outer diameter d ₃ which is slightly less than d _lf thereby allowing the shaft 528 to fit tightly within the bore's first cylindrical portion 514. Likewise the piston cup 530 has an outer diameter d ₄ which is slightly less than d ₂ , thereby allowing the cup 530 to fit tightly within the bore's second cylindrical portion

516. The cup 530 has a rear surface 532 which faces the piston shaft 528. The cup includes grooves 534 around its outer circumferential surface for seating piston O-rings 536 therein. Likewise, the inner circumferential surface of the bore's first cylindrical portion 514 includes grooves 538 around its circumference for seating O-rings 540 therein. The cup 530 also includes a cup-shaped insert 538 for holding one end of biasing spring 542 therein.

The EETC valve 500 is biased in the closed position by the biasing spring 542 which is mounted at the one end to an inner surface of the cup's insert 538 and at the other end to an inner surface of the cover 510. To hold the other end of the spring 542 in place, the cover 510 includes knob 544 which extends perpendicularly into the bore 506 from the center of its inner surface, the other spring end being seated around the knob 544.

To move the EETC valve 500 from its first position to its second position, the valve associated with the fluid injector 18 is opened in response to a control signal from an ECU (not shown). Simultaneously, the valve associated with the fluid injector 20 is closed, if it is not already closed. Pressurized hydraulic fluid from the fluid inlet tube 36 flows through the injector 18 and into the chamber 526, where it pushes against the piston cup's rear surface 532. When the fluid pressure against the cup's rear surface 532 exceeds the opposing force of the biasing spring 542, the piston head 504 moves to the left until it reaches the second position shown in phantom, thereby causing the piston shaft 528 to move away from the first opening 522. The TCF in the passageway 524 can now flow through the right hand portion of the housing 502 and into the radiator. A pressure sensor (not shown) and the ECU (not shown) cooperate in the same manner as described with respect to the EETC valve 10 to determine when to close the valve of the hydraulic fluid injector 20, thereby trapping the hydraulic fluid in the chamber 526. Thus, the piston shaft 528 will remain in the second position as long as the fluid injector valves remain closed. The O-rings 536 and 540 prevent the hydraulic fluid in the chamber 526 from leaking out into other parts of the housing 502.

Likewise, the O-rings 540 prevent the TCF from leaking into other parts of the housing 502.

When it is desired to close the EETC valve 500, those steps are reversed. That is, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 18 to close the injector's valve, if it is not already closed. Simultaneously, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 20 to open that injector's valve. The pressurized hydraulic fluid inside the chamber 526 flows out through the housing's second opening (not shown), through the open valve of the hydraulic fluid injector 20 and into the fluid outlet tube 38. As the hydraulic fluid empties out of the chamber 526, the biasing spring 542 pushes the piston head to the right and into the first position, thereby causing the piston shaft 528 to block the first opening 522 and shut off fluid flow through the EETC valve 500. When the pressure sensor (not shown) detects that the chamber 526 is no longer pressurized, it causes the ECU to send a control signal to the solenoid of the hydraulic fluid injector 20 to close that injector's valve.

Figs. 11 and 12 show a flow-through version of a piston valve suitable for use as an EETC valve. Fig. 11 shows a sectional side view of EETC valve 600 and Fig. 12 shows a right end view of the EETC valve 600 in Fig. 11. The solid lines in Fig. 11 shows the EETC valve 600 in its first position which is associated with a valve "closed" state. Fig. 11 also shows the valve's second position in phantom which is associated with a valve "open" state. For clarity, Figs. 11 and 12 are described together.

The EETC valve 600 includes valve mechanism casing or housing 602, piston head 604, an inlet hydraulic fluid injector 18 and an outlet hydraulic fluid injector 20. Only the inlet hydraulic fluid injector 18 is visible in Fig. 11, whereas both injectors 18, 20 are visible in Fig. 12. Injector 18 is connected to fluid inlet tube 36 and injector 20 is connected to fluid outlet tube 38, in the same manner as the valves 10 and 100.

The housing 602 is a generally cylindrical solid structure having a bore 606 therethrough. The housing 602 is closed at one end 608 and open at the other end 612. The housing 602 is defined by five main parts, including three cylindrical portions and two barrels. The three cylindrical portions are, from left to right, a first cylindrical portion 614 having an inner diameter of about d,, a second cylindrical portion 616 having an inner diameter of about d ₂ and a third cylindrical portion 617 having an inner diameter of about d ₃ . The diameter d ₂ is larger than d, and the diameter d ₃ is about the same as d The first cylindrical portion 614 is closed at the left end (which corresponds to the closed housing end 608) and open at the right end. The second and third cylindrical portions 616 and 617 are open at both ends. The right end of the third cylindrical portion 617 corresponds to the open housing end 612. The third cylindrical portion 617 is a separate structural piece and is bolted to the second cylindrical portion 616 by an integral circular flange 646. The left end of the third cylindrical portion 617 extends slightly into the right end of the second cylindrical portion 616. Two barrels 618, 620 extend from the housing 602, each barrel housing one of the fluid injectors 18, 20. Barrel 618 and injector 18 are visible in Fig. 9. Only the barrel 618 is visible in Fig. 11, whereas both barrels 618, 620 are visible in Fig. 12. The housing 602 also includes two openings therethrough. A first opening 622 located near the left end of the first cylindrical portion 614 allows temperature control fluid (TCF) from passageway 624 to pass therethrough when the first opening 622 is not obstructed by the piston head 604. A second opening (not shown) allows hydraulic fluid to flow into and out of a chamber 626 within the housing's second cylindrical portion 616, to and from the pair of fluid injectors 18, 20. Fluid pressure sensor 650 is in communication with the chamber 626. The sensor 650 is visible in Fig. 12 but is not visible in Fig. 10. This sensor 650 performs the same function as the fluid pressure sensor 28 in the EETC valve 10.

The piston head 604 is a unitary solid structure defined by two main parts, a hollow piston shaft 628 and a piston cup 630 connected to one end of the shaft 628. Unlike the other end of the shaft 528 in the piston head 504, the other end of the shaft 628 (i.e. , the left end) is open. Also, a center region of the piston cup 630 is hollow. The piston cup 630 and the right hand portion of the piston shaft 628 reciprocate within the second cylindrical portion 616 of the housing 602. The piston shaft 628 is a preselected length which allows its outer circumferential wall to block the first opening 622 when the piston head 604 is in the first position and allows its outer circumferential wall to move completely away from the first opening 622 when the piston head 604 is in the second position. The piston shaft 628 has an outer diameter d ₄ which is slightly less than d _t , thereby allowing the shaft 628 to fit tightly within the bore's first cylindrical portion 614. Likewise the piston cup 630 has an outer diameter d ₅ which is slightly less than d ₂ , thereby allowing the cup 630 to fit tightly within the bore's second cylindrical portion 616. The cup 630 has a rear surface 632 which faces the piston shaft 628. The cup includes grooves 634 around its outer circumferential surface for seating piston O-rings 636 therein. Likewise, the inner circumferential surface of the bore's first cylindrical portion 614 includes grooves 638 around its circumference for seating O-rings 640 therein. The EETC valve 600 is biased in the closed position by biasing spring 642 which is seated at one end against the cup's inner surface 648, and at the other end around the outer circumference of the left end of the third cylindrical portion 617. The far end of the spring's other end lies against the circular flange 646. To move the EETC valve 600 from its first position to its second position, the valve associated with the fluid injector 18 is opened in response to a control signal from an ECU (not shown). Simultaneously, the valve associated with the fluid injector 20 is closed. Pressurized hydraulic fluid from the fluid inlet tube 36 flows through the injector 18 and into the chamber 626, where it pushes against the piston cup's rear surface 632. When the fluid

pressure against the cup's rear surface 632 exceeds the opposing force of the biasing spring 642, the piston head 604 moves to the right until it reaches the second position shown in phantom, thereby causing the piston shaft 628 to move away from the first opening 622. The TCF in the passageway 624 can now flow through the hollow interior of the piston head 604, through the right hand portion of the housing 602 (i.e., the third cylindrical portion 617) and into the radiator. The hydraulic fluid remains trapped in the chamber 626 because the only outlet passageway, the valve of the hydraulic fluid injector 20, is closed. Thus, the piston shaft 628 will remain in the second position as long as the states of the fluid injector valves are not changed. The O-rings 636 and 640 prevent the hydraulic fluid in the chamber 626 from leaking out into other parts of the housing 602. Likewise, the O-rings 640 prevent the TCF from leaking into other parts of the housing 602.

When it is desired to close the EETC valve 600, those steps are reversed. That is, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 18 to close the injector's valve. Simultaneously, the ECU sends a control signal to the solenoid of the hydraulic fluid injector 20 to open that injector's valve. The pressurized hydraulic fluid inside the chamber 626 flows out through the housing's second opening (not shown), through the open valve of the hydraulic fluid injector 20 and into the fluid outlet tube 38. As the hydraulic fluid empties out of the chamber 626, the biasing spring 642 pushes the piston head 604 to the left and into the first position, thereby causing the piston shaft 628 to block the first opening 622 and shut off fluid flow through the EETC valve 600. The hydraulic fluid flow paths in the EETC valves 500 and 600 differ slightly from the paths in the EETC valves 10 and 100. In the EETC valves 500 and 600, the hydraulic fluid does not flow through any common passages or passageways between the injectors and the valve chamber. Instead, each injector is in direct communication with the valve chamber. This feature

is illustrated in Figs. 10 and 12 by respective phantom dashed lines 552 and 652 which extend from the fluid injectors into the valve chamber.

Figs. 16A and 16B show a hydraulic fluid injector 700 in cross- section which is suitable for controlling the state or position of the EETC valves in the invention. As noted above, the fluid injector 700 is solenoid activated and includes an electrical terminal 702 connected at one end to injector solenoid 704 and at the other end to an ECU (not shown). When the solenoid 704 is energized, it causes needle valve 706 to move up, thereby moving it away from seat 708 and opening orifice 710 to fluid flow. When the solenoid 704 is deenergized, biasing spring 712 causes the needle valve 706 to return to the closed position.

Fig. 16A shows the inlet fluid flow path from a source of pressurized hydraulic fluid, through the injector and to the valve chamber. The valve in this figure thus performs the function of the valve 18 in Fig. 4. Fig 16B shows the outlet fluid flow path from the valve chamber, through the injector and to a reservoir of hydraulic fluid. The valve in this figure thus performs the function of the valve 20 in Fig. 4.

The fluid injector 700 is similar to a DEKA Type II bottom feed injector, commercially manufactured by Siemens Automotive, Newport News, VA. Although this injector is typically employed to inject metered quantities of gasoline into the combustion chamber of an engine, it can also function as a valve to pass other types of hydraulic fluid therethrough. When the hydraulic fluid is engine lubrication oil, the Siemens type injector can be employed with only minor modifications such as an increased lift or stroke (e.g., .016 inches [0.04064 cm], instead of .010 inches [0.0254 cm]) and a larger flow orifice for increased flow capacity. Also, since engine oil is not as corrosive as gasoline, internal components of the Siemens type injector do not need to be plated. Furthermore, the filter associated with commercially available injectors is not employed.

The inlet fluid injector 700 is preferably operated in a reverse flow pattern. That is, fluid flows through the inlet injector 700 in an opposite direction as the injector is normally employed in a gasoline engine. When the inlet injector 700 is operated in this manner, pressure from the valve chamber tends to seal the needle valve 706 against its seat 708, thereby lessening the tendency of the injector 700 to leak.

Fig. 16C shows an alternative type of hydraulic fluid injector 800 in cross-section which is suitable for controlling the state or position of the EETC valves in the invention. The injector 800 is similar to a DEKA Type I top feed injector, commercially manufactured by Siemens Automotive, Newport News, VA. In this type of injector, the hydraulic fluid flows through the entire length. Although Fig. 16C shows both fluid flow paths through the same injector 800, only one injector 800 is employed for each path. The injector 800 is also preferably operated in a reverse flow pattern and without a filter. This type of injector has a numerous advantages over the DEKA Type II injector.

When employing the injector 800 in an EETC valve, the top of the injector 800 is connected directly to the EETC valve's upper chamber, not to a common passage. This allows for more versatile packaging configurations because the inlet and outlet injectors do not need to be physically near each other. It also reduces the amount of retained trapped air in the EETC valve, potentially eliminating the need to bleed out trapped air when filling the chamber. The injector 800 is also smaller and cheaper than the injector 700. One disadvantage of this type of injector is that it is more difficult to get hydraulic fluid such as oil to flow smoothly therethrough. Fig. 17 shows a block diagram circuit of the connections to and from ECU 900 for controlling the state or position of the EETC valves. The ECU 900 receives sensor output signals from at least the following sources: 1. an ambient air sensor in an air cleaner (clean side);

2. a temperature sensor at the end of the engine block's temperature control fluid water jacket;

3. a pressure sensor in the engine block's temperature control fluid water jacket;

4. a temperature sensor in the engine block oil line;

5. a pressure sensor in the engine block oil line; and

6. a pressure sensor in the EETC valve's hydraulic fluid passageway.

The ECU 900 utilizes some or all of those sensor signals to generate open/close command signals for the fluid injectors of the EETC valve.

As noted above, the hydraulic fluid pressure signals are also employed to detect unsafe operating conditions. The engine oil fluid pressure signal can be employed to detect unsafe operating conditions and/or to determine when the oil lubrication system is sufficiently pressurized to allow for proper operation of the EETC valve.

A typical control routine for opening a diaphragm type EETC valve sized to replace a prior art wax pellet or bimetallic coil type thermostat and employing fluid injectors connected to the engine lubrication oil system is as follows: 1. If engine is being started, wait appropriate amount of time until engine oil is adequately pressurized. It will typically take two to three seconds to allow it to reach a minimum pressure of 40 psi (276 kPa).

2. Activate solenoid of inlet fluid injector to open its valve. (Close valve of outlet fluid injector, if it is not already closed.)

3. Wait until chamber pressure (as measured by the fluid pressure sensor) reaches about 25 psi (172 kPa).

4. Activate a two second timer in the ECU. 5. After two seconds, deactivate the solenoid of the inlet fluid injector to close its valve.

6. If the fluid pressure sensor detects a pressure drop below 25 psi (172 kPa), repeat steps 2-5.

If the engine oil is warm, the total time to complete steps 2-5 will be about six seconds. If the engine oil is cold, step 2 will take longer, thereby lengthening the total time.

The ECU 900 can also perform other emergency control functions to maintain the TCF in a safe range. For example, in extremely hot ambient air conditions, the temperature of the TCF might exceed a safe range, even if the EETC valve is fully open. In typical prior art vehicles, an overheating condition will be signalled to the driver through a dashboard mounted engine warning light or the like. The novel system shown in Fig. 17 can respond to this condition by temporarily opening the heater core valve and/or shutting off the vehicle's air conditioning system. The first of these measures will assist in removing excess heat from the engine block. The second of these measures will reduce the load on the engine, thereby reducing its heat energy output. If these measures still fail to reduce the temperature of the TCF to a safe range, the system can then activate the engine warning light. Another dashboard mounted light can indicate when the ECU has taken emergency control of the vehicle's climate control system.

Likewise, in extremely cold, sub-zero ambient air temperatures (below -17.8°C), the heater core valve can be automatically deactivated to avoid draining heat energy from the engine block until the temperature of the TCF reaches an acceptable minimum level. One example of how the ECU 900 controls the state or position of an EETC valve based on specific parameters is described in Figs. 19-21 of this disclosure.

Fig. 18 diagrammatically shows the flow path of the TCF diverted from the passageway 156 in Fig. 7. When the EETC valve 100 is in its first position, a portion of the TCF in the passageway 156 flows through the

opening 158 and into the passageway 160. The passageway 160 is connected to one end of passage 802 drilled through the engine block. The other end of the passage 802 is connected to the inlet end of the heat conductive tube 220 inside the engine block oil pan 94. The passage 802 is sealed at both ends by O-rings 804 to prevent leakage of the TCF into the oil pan 94. The O-rings 804 also function to insulate the passage 802 from the oil pan 94 and the passageway 160. Alternatively, if drilling a passage through the engine block is not practical or desired, the passageway 160 and the inlet end of the tube 220 can be connected to ends of an insulated tube exterior to the engine block. The outlet end of the heat conductive tube 220 is connected to a passageway leading to the water pump inlet (not shown). The tube 220 is secured inside the oil pan 94 by hanger 806 attached to the engine block. The hanger 806 is insulated to prevent it from conducting heat energy from the tube 220 into the engine block. The hanger 806 also cushions the tube 220 from engine vibrations. Suction through the tube 220 is enhanced by placing the outlet end close to the water pump inlet.

The passageway 160 can also lead to other passages and tubes disposed in other engine parts, thereby allowing the TCF to warm or heat those other parts too. For example, additional TCF passages can lead to tubes disposed in the reservoir of the automatic transmission, the brake system's master cylinder or ABS system, windshield washer fluid or the like. The TCF would then flow to these parts whenever it flows to the oil pan. Alternatively, flow to one or more of these parts can be controlled by a separate flow control valve so that when the TCF flows to the oU pan, the fluid selectively flows to desired parts in accordance with different temperature parameters.

The EETC valves described herein are designed to replace the prior art wax pellet type or bimetallic coil type thermostat. These thermostats are typically located in an opening connecting a radiator inlet passage to an outlet of an engine water jacket. Accordingly, the EETC valves are dimensioned to fit into that opening. Likewise, the EETC valve housing

includes holes to allow the valves to be mounted in that opening in the same manner as the prior art thermostats are mounted within the engine. Thus, the EETC valves can be retrofitted into existing engine TCF passageways. The only additional apparatus required to install the EETC valve 10, 500 and 600 are the hydraulic fluid lines and electrical wires for connection to the inlet and outlet hydraulic fluid injectors. These lines and wires can be placed inside the engine compartment wherever space permits. To install the EETC valve 100, the TCF passageway must be slightly modified to provide the extra passageways shown diagrammatically in Fig. 14. Likewise, if the EETC valve 100 is employed to control the intake manifold flow control valve 300, the fluid outlet tube 174 must be provided from the EETC valve 100 to the valve 300.

Notwithstanding the above discussion of the valve location, the EETC valve can alternatively be located wherever it can properly perform the function(s) attributed thereto. Likewise, the EETC valve can have other sizes which are appropriate for its alternative location.

The EETC valves are suitable for any form of internal combustion engine which opens and closes an engine block TCF passageway to a radiator. Thus, both gasoline and diesel engine environments are within the scope of the invention. Although the hydraulic fluid which controls the state or position of the EETC valve is preferably engine oil, it can be any type of pressurized hydraulic fluid associated with a vehicle powered by an internal combustion engine. In one alternative embodiment, the hydraulic fluid is power steering fluid wherein the source of the pressurized hydraulic fluid is the high pressure line of a power steering pump. The hydraulic fluid emptied from the EETC valve flows into the power steering fluid reservoir. In this embodiment, the power steering pump is modified so that it provides high pressure at all times. That is, high pressure can be tapped from the pump when the wheel is not being turned and when the engine is off, in addition to when the wheel is being turned. Also, this version employs a prior art pressure regulating valve in the

high pressure line to achieve a constant output pressure of about 10 to about 120 psi (69 to 827 kPa), regardless of the varying input pressure of the power steering unit, which can range up to 1000 psi 6895 kPa). In this manner, the EETC valve is never exposed to pressures exceeding about 120 psi (827 kPa), regardless of the output pressure of the power steering unit.

In another alternative embodiment, a separate hydraulic fluid system operates the EETC valve. This embodiment would require many components to be uniquely dedicated to the task, and thus would significantly increase the cost of the system. Dead heading or restricting TCF flow through portions of the water jacket reduces heat loss from the engine block. It also reduces the mass of TCF circulating through the water jacket, thereby raising the temperature of the circulating mass above what it would be if the mass was larger. Both of these effects allows the engine block to warm up more quickly. As noted above, heat energy is primarily transferred to and from the engine block by the flow of fluid. Therefore, dead heading or restricting the flow will have almost the same effect as shutting off the flow. Since dead heading or restricting TCF flow effectively traps all or part of the TCF in the dead headed or restricted passageway, the trapped TCF acts as an insulator. This insulation function further reduces heat loss from the engine block.

Some of the preferred materials for constructing the EETC valve and operating parameters were described above. In one embodiment of the invention, the following materials and operating parameters were found to be suitable for a diaphragm type EETC valve. Biasing spring - stainless steel

Valve housing and cover - glass filled nylon injection molded is preferred, aluminum is also acceptable

Wall thickness of diaphragm valve body and cover - .090 inches

(0.229 cm) Air bleed opening - .060 inches diameter (0.152 cm)

Valve rod - cored out to obtain uniform thickness for injection molding

Diaphragm stroke - up to one inch (2.54 cm)

U-shaped tube in oil pan - two feet length (0.6096 m), or more Minimum valve operation pressure - 20 psi (138 kPa) (i.e. , valve will open at 20 psi. [138 kPa]). This will be sufficient for most engines which operate with engine lubrication oil pressures in the range from about 37 psi. (255 kPa) (at the lowest idle speed) to about 75 psi (517 kPa). Maximum valve operation pressure - 120 psi (827 kPa).

The ECU 900 can be programmed with specific information to control the state of the EETC valves and any restrictor/shutoff valves 300 and/or 400 associated therewith. Figs. 19 and 20 show one example of how the ECU 900 is programmed with information to control the state of an EETC valve based upon the temperature of the TCF and the ambient air temperature, whereas Fig. 21 shows the state of prior art wax pellet type or bimetallic coil type thermostats within the same ranges of temperatures. Turning first to Fig. 21, prior art wax pellet type or bimetallic coil type thermostats are factory set to open and close at a preselected coolant temperature. Thus, the state of these thermostats are not affected by the ambient air temperature. That is, no matter how cold the ambient air temperature becomes, these thermostats will open when the coolant temperature reaches the factory set value. A thermostat designed for use in a cooling system employing a permanent type antifreeze (as opposed to an alcohol type antifreeze) is typically calibrated to open at about 188 (86.7°C) to about 195 (90.56°C) degrees Fahrenheit and be fully open between about 210 (98.9°C) to about 212 (100°C) degrees Fahrenheit. Since the EETC valves in the invention are computer controlled, their states can be set to optimize engine temperature conditions over a wide

range of ambient air temperatures and TCF temperatures. In one embodiment, the ECU 900 in Fig. 17 is programmed with the curve shown in Fig. 19. The curve is defined by a two-dimensional mathematical function of tl =/(t2), where tl is the temperamre of the TCF in the engine block and t2 is the ambient air temperature, tl and t2 being axes on an orthogonal coordinate system. The curve divides the coordinate system into two regions, one on either side of the curve.

In operation, the ECU 900 continuously monitors the ambient air temperature and the TCF temperature to determine what state the EETC valve should be in. If coordinate pairs of these values lie in region 1 of the Fig. 19 graph, the EETC valve is closed (or remains closed if it is already in that state). Likewise, if coordinate pairs of these values lie in region 2, the EETC valve is opened (or remains open if it is already in that state). If coordinate pairs lie exactly on the curve, the ECU is programmed to either automatically select one of the two regions or to modify one or both of the values so that the coordinate pair does not lie exactly on the curve.

The curve shown in Fig. 19 has been experimentally determined to provide optimum engine temperature control in a typical internal combustion engine when an EETC valve replaces the typical prior art thermostats described above. However, the curve can be different, depending upon the desired operating parameters of the engine and its accessories. An engine employing an EETC valve which is controlled according to the curve in Fig. 19 will have lower emissions, better fuel economy and a more responsive vehicle climate control system than the same engine employing the thermostat. These improvements will be greatest in the lower ambient temperature ranges.

To illustrate some advantages of the EETC system, consider a vehicle which is first started up when the ambient air temperature is zero degrees Fahrenheit (-17.8°C). Until the coolant or TCF temperature reaches about 188 degrees Fahrenheit, the prior art system in Fig. 21 and the EETC system in Fig. 19 will both prevent the coolant or TCF from flowing through

the radiator. However, when the coolant temperamre exceeds about 188 degrees Fahrenheit (86.7°C), the prior art system wUl open the thermostat and allow either some or virtually all of the coolant to flow through the radiator, thereby lowering the coolant temperature. This reduces the abUity of the vehicle's heater/defroster to deliver hot air (i.e. , heat) to the vehicle interior and windows because the coolant flowing through the heater core will be cooler than if it did not flow through the radiator. Furthermore, this also unnecessarily removes valuable heat energy from the engine block.

When the ambient temperature is zero degrees Fahrenheit (-17.8 °C), typical internal combustion engines often do not need to be cooled by coolant flow through the water jacket since the ambient air presents a significant heat sink. Furthermore, when the ambient air temperature is about zero degrees Fahrenheit (-17.8 °C), the heat energy emitted by engine combustion often does not raise the oil temperature or the engine block above the level desired for safe and optimum operation. In fact, in sub-zero ambient air temperatures (below -17.8°C), the engine block of a typical internal combustion engine wiU have an average temperature of less than 150 degrees Fahrenheit (65.6°C) which is less than the ideal operating temperature. Accordingly, high oil viscosity and sludge build-up, which increases emissions and lowers fuel economy, are virtually unavoidable conditions when operating engines having prior art thermostat controlled cooling systems in sub-zero ambient air temperatures (below - 17.8°C).

Consider the same vehicle operating in the same ambient temperature environment with an EETC valve system. As shown in Fig. 19, the EETC valve will remain closed until the TCF exceeds about 260 degrees Fahrenheit (126.7 °C), a condition that might not even occur unless the engine is driven very hard and/or fast. Consequently, the TCF flowing through the engine water jacket will not unnecessarily remove valuable heat energy from the engine block and engine lubrication oil. Furthermore, the TCF flowing through the heater core will become hot more quickly and wiU remain hotter than the

coolant in the Fig. 21 scenario, thereby resulting in improved defrosting and vehicle interior heating capabilities.

In a control system employing the curve in Fig. 19, the EETC valve can be any of the valves described in the invention. If the EETC valve is employed in conjunction with one or more of the restrictor/shutoff flow control valves 300 or 400, the curve can be slightly modified to obtain optimum temperature control conditions. Specifically, the portion of the curve between about 58 (14.4°C) to about 80 (26.67°C) degrees Fahrenheit can have the same slope as the portion of the curve between about 60 (15.6°C) degrees to about zero (-17.8°C) degrees Fahrenheit.

When the EETC valve is employed in conjunction with the additional flow control valves, emission levels will even be lower, fuel economy even greater, and the vehicle climate control system even more responsive than the system employing only the EETC valve. If the EETC valve 100 is employed in the system, hot ETC will flow through the oil pan at virtually all times when the ambient air temperamre is zero degrees Fahrenheit (-17.8°C). This will improve the oil viscosity and reduce engine sludge build-up.

When the EETC valve is employed in conjunction with the intake manifold flow control valve 300, engine performance improvements will occur in high temperamre environments as a result of avoiding excessive heating of the intake mamfold, as discussed above with respect to the system in Fig. 14.

When the EETC valve is employed in conjunction with flow control valves associated with the cylinder head and/or cylinder block, very precise tailoring of engine temperamre can be achieved. For example, when the ambient temperamre is very low and the EETC valve is closed, the one or more flow control valves are likewise closed to restrict and/or dead head the TCF that would ordinarily flow through certain portions of the engine block. Preferably, the TCF is allowed to flow only through the hottest portions of the engine block, such as areas of the cylinder head jacket closest to the cylinders. This achieves at least two desired effects. First, the TCF flowing through the limited

portions of the engine water jacket will not unnecessarily remove valuable heat energy from the engine block and engine lubrication oil. Second, the limited amount of the TCF which exits the water jacket will be hotter than if the TCF flowed through all parts of the engine block. Thus, the TCF flowing through the heater core will become hot more quickly and will remain hotter than if the TCF flowed through all parts of the engine block, thereby resulting in improved defrosting and vehicle interior heating capabilities.

Fig. 22 A shows a valve state graph which employs a curve similar to the curve in Fig. 20 but which employs the valve states to control the state of the EETC valve and two restrictor/shutoff valves. In region 1, the EETC valve is closed and the restrictor/shutoff valves are in an restricted/blocked state. In region 2, the EETC valve is open and the restrictor/shutoff valves are in an unrestricted/unblocked state.

Fig. 23 graphically shows a dotted curve of the actual temperamre of the temperamre control fluid measured in an engine block of a GM 3800 transverse engine equipped with an EETC valve and two restrictor/shutoff valves when the state of the valves are controlled according to the Fig. 22 A scheme. The restrictor/shutoff valves are located on either sides of a V-shaped engine block in the outer TCF flow passages around the cylinder liner, and together restrict the flow through the engine block by about 50 percent in their fully restricted state. Fig. 23 also shows a dashed curve of the actual temperature of engine coolant measured in the engine block when a prior art wax pellet type or bimetallic coU type thermostat is employed and its state determined according to the prior art Fig. 21 scheme. The prior art thermostat operates to try to maintain a constant coolant temperamre in a range from about 180 (82.2°C) to about 190 (87.8°C) degrees Fahrenheit. However, when the ambient air temperature is very hot (e.g. , 100 degrees Fahrenheit [37.8°C]), the coolant temperamre will exceed the desired range even if the thermostat is fully open. This is because the ability of the vehicle's cooling system to cool the coolant is dependent upon the

capacity of the radiator. It is usually impractical and too expensive to install a radiator large enough to maintain temperamres below 200 degrees Fahrenheit (93.3 °C) at all times. Thus, regardless of the type of flow control valves employed in the vehicle's engine, coolant temperamres will exceed the optimal range in hot weather conditions.

In very cold ambient temperamres such as sub-zero temperatures (below -17.8°C), the coolant temperamre in the prior art system wUl be below the desired range and will continue to decrease with decreasing ambient air temperatures. This will cause a significant decrease in fuel economy and a significant increase in exhaust emissions for all of the reasons discussed above. Sludge formation will also be a significant problem.

The system employing the EETC valve and restrictor/shutoff valves show an improved TCF temperamre curve because it maintains the TCF temperamre more closely to the optimum range throughout a greater ambient temperamre range. When the ambient air temperamre is very hot (e.g., 100 degrees Fahrenheit [37.8°C]) and full flow through the radiator has begun, the TCF temperamre will be slightly less than the coolant temperamre in the prior art system, mainly as a result of the greater flow allowed through the EETC valve, as compared to the prior art wax pellet type thermostat. However, the cooling capabUity of the system in the invention will still be limited by the fixed capacity of the radiator.

In cold ambient air temperamres, especially sub-zero temperatures (below -17.8°C), the system in the invention maintains the TCF temperamre at values significantly higher than the coolant temperature in the prior art system. This is because the restrictor/shutoff valves have been placed in the state where they restrict or shut off a portion of flow through the engine block. This flow restriction reduces the heat energy loss from the engine block, thereby allowing the limited amount of flowing TCF to reach a greater temperature. The engine block heat energy loss is reduced in at least two ways. First, less TCF flows through the water jacket so less heat energy is transferred to the TCF where it

is lost to the atmosphere. Second, the restricted and/or trapped TCF acts as an insulator around portions of the engine block. Since the limited amount of flowing TCF is at a greater temperamre than the prior art coolant, the TCF improves the operating capability of the vehicle interior heater and defroster. Furthermore, since the engine operates at a hotter temperamre, engine out exhaust emissions are lower, fuel economy is greater than in the prior art system. Also, sludge is less likely to form in the engine.

Instead of controlling the state of the EETC valve and restrictor/shutoff valves in accordance with the curve shown in Fig. 22A, the EETC valve and restrictor/shutoff valves can be controlled according to separate curves, as shown in Fig. 22B. By employing separate curves, the flow of TCF can be more precisely tailored to achieve a more optimum actual TCF temperamre in Fig. 23. At very high ambient air temperamres, the EETC valve should normally be fully open and the restrictor/shutoff valves should normally be fully unrestricted/unblocked. At very low ambient air temperamres, the EETC valve should normally be fully closed and the restrictor/shutoff valves should normally be fully restricted/blocked. However, it may be more desirable for ideal engine operating conditions to keep one or both of the restrictor/shutoff valves open in mid-temperature ranges, even after the EETC valve has closed. Fig. 22B shows a region 3 wherein these dual states are achieved. In one embodiment of the invention, a TCF temperamre differential of about 15 degrees Fahrenheit is employed.

A system employing the curves shown in Fig. 22B will allow the restrictor/shutoff valve(s) to open or unblock the TCF passageway shortly before the EETC valve opens flow to the radiator at a given ambient air temperamre. One advantage of this system is that the temperature of the TCF circulating through the engine block's water jacket wUl become more homogeneous by opening the restrictor/shutoff valves before the EETC valve is opened, thereby improving the overall accuracy of the system in determining when to open the EETC valve. This is because the total TCF mass wiU be

heated to the desired programmed temperamre (as determined by the EETC valve curve) before TCF flow is induced through the radiator.

When the restrictor/shutoff valves are in their restricted or blocked position, the temperamre TCF in different portions of the engine block can vary significantly. For example, if the fluid in the outer water jacket passageways is dead headed, it will be colder than the fluid in the inner water jacket passageways. When the restrictor/shutoff valves are opened, the hotter and colder fluids immediately begin to mix, thereby reducing the variation in temperature of the TCF in different portions of the water jacket. Thus, as the TCF continues to heat up, the measured TCF temperamre, which determines when to open the EETC valve, will be more accurate.

The EETC valve described herein can be employed with one or more restrictor/shutoff flow control valves to improve the temperamre control function of the system over that which would be achieved when employing only the EETC valve, with or without its optional oil pan heating feature. As noted above, the restrictor/shutoff flow control valves 300 and 400 shown in Fig. 14 can be any type suitable for the task. However, one type of novel restrictor/shutoff flow control valve particularly suitable for this task is disclosed in Figs. 24-30. The novel valve, labelled as 1000 in the figures, shares many characteristics with the flow-through piston type EETC valve 600 described with respect to Fig. 11, including the following similarities:

1. The state or position of the flow control valve 1000 is controlled by the position of a reciprocating piston mechanism. 2. The position of the reciprocating piston mechanism is controlled by pressurized hydraulic fluid in a valve chamber and a biasing spring.

The hydraulic fluid enter and exits the valve chamber through a pair of hydraulic fluid injectors.

Fig. 24 is a diagrammatic sectional view of a typical prior art four cylinder engine block showing three flow control valves 1000,, 1000 ₂ and 1000 ₃ which restrict TCF flow through portions of engine block TCF passageways 1002,, 1002 ₂ and 1002 ₃ , respectively, and one flow control valve 1000 ₄ which blocks TCF flow through intake line 1003 associated with an intake manifold. (The outtake line associated with the intake manifold is not visible in this view.) The manner in which a flow control valve 1000 blocks flow, as opposed to restricting flow, is best illustrated with respect to Fig. 29, described below. In one embodiment of a system shown in Fig. 14, the flow control valve 300 is similar to the flow control valve 1000 ₄ , whereas the flow control valve 400 is equivalent to one of the flow control valves 1000,, 1000 ₂ and 1000 ₃ .

Fig. 24 also shows EETC valve 1006 for controlling flow of the TCF to the radiator, and heater control valve 1008 for controlling flow of the TCF to the heater core. The state or position of the EETC valve 1006 and the flow control valves 1000,, 1000 ₂ , 1000 ₃ and 1000 ₃ are controlled by hydraulic fluid injector pairs 1010, as described above. Fig. 24 only shows one pair of hydraulic fluid injectors 1010 which simultaneously controls the state of the flow control valves 1000,, 1000 ₂ and 1000 ₃ . The state of the flow control valve 1000 ₄ may be controlled by a separate pair of injectors 1010 (not shown), or may be controlled by the injectors associated with the EETC valve 1006 (not shown). The pair of injectors 1010 shown in Fig. 24 includes fluid inlet tube 1012 connected to a source of pressurized hydraulic fluid 1014 and fluid outlet tube 1016 connected to hydraulic fluid reservoir 1018. In this embodiment, the source of pressurized hydraulic fluid 1014 is engine lubrication oil from an oil pump, whereas the hydraulic fluid reservoir 1016 is the oil pan.

Figs. 25 and 26 show the restrictor/shutoff valve 1000. Fig. 25 shows a sectional side view of the valve 1000 mounted in a TCF passageway. The solid lines in Fig. 25 show the valve 1000 in a first position which is associated with a valve "open" or unrestricted/unblocked state. Fig. 25 also

shows, in phantom, the valve 1000 in a second position which is associated with a valve "closed" or restricted/blocked state. Fig. 26 shows an exploded view of the parts of the valve 1000. For clarity, Figs. 24, 25 and 26 are described together. The restrictor/shutoff valve 1000 includes, among other parts, valve mechanism casing or housing 1020, piston 1022, reciprocating shaft 1024 and piston valve seal or plug 1026. An inlet/outlet tube 1028 attached to the rear of the housing 1020 is in fluid communication with the pair of the hydraulic fluid injectors 1010 associated with the valve 1000. If the valve 1000 is not controlled by the remote pair of injectors 1010 (as shown in Fig. 24), the injectors 1010 are part of the valve 1000 itself. The pair of hydraulic fluid injectors 1010 are similar to the injectors 18, 20. The housing 1020 is a generally cylindrical solid structure having a bore 1030 therethrough. The bore 1030 has a generally uniform inner diameter of d _v The housing bore 1030 is partially closed at left end or near end 1032 by circular plate 1035, described in more detail below. Circular mounting flange 1038 extends perpendicularly outward from the outer circumferential walls of the housing's near end 1032. The mounting flange 1038 includes a plurality of holes 1040 therethrough for receiving a series of bolts 1042 which attach the valve 1000 to solid wall 1046 surrounding first passageway 1048. Gasket 1049 is disposed between the mounting flange 1038 and the outer facing surface of the wall 1046. When the valve 1000 is employed in the environment described herein, the solid wall 1046 is either part of an engine block or intake manifold surrounding a TCF passageway. The housing bore 1030 is closed at right end or far end 1034, except for opening 1036 therethrough. One end of the inlet/outlet tube 1028 is attached to the housing opening 1036, thereby placing the hydraulic fluid injectors 1010 in fluid communication with the housing bore 1030.

The piston 1022 and reciprocating shaft 1024 are disposed in the bore 1030 and have generally uniform outer diameters of d ₂ and d ₃ ,

respectively. Diameters d ₂ and d ₃ are generally equal, and are slightly less than d _j , thereby allowing the piston 1022 and reciprocating shaft 1024 to fit tightly in the bore 1030. The piston 1022 includes front or left outer facing surface 1050 and rear or right outer facing surface 1052. The piston 1022 also includes grooves around its outer circumferential surface for seating O-rings 1054 therein. The reciprocating shaft 1024 is a generally cylindrical hollow solid structure which is open at left end or near end 1056 and closed at right end or far end 1058. The shaft's far end 1058 has an outer facing surface 1060 and an inner facing surface 1062. The outer facing surface 1060 lies adjacent to, and in contact with the piston's left outer facing surface 1050. The shaft 1024 includes four cut-outs along a near end or leftmost portion of its longitudinal axis. One cut-out 1064 is labelled in Fig. 26. The cut-outs 1064 are equally spaced around the shaft's outer circumference. In this manner, the cut-outs 1064 form four fingers 1068 from that portion of the shaft's outer circumferential wall. Each finger 1068 has an end surface 1069 with shouldered edges 1094.

Biasing spring 1070 is disposed inside of the hollow reciprocating shaft 1024. One end of the spring 1070 lies against the shaft's inner facing surface 1062 and the other end of the spring 1070 lies against an inner facing surface of the circular plate 1035.

The plate 1035 includes four cut-outs 1072 therethrough which have the same general shape as the shaft finger's end surfaces 1069 as they would appear without the shouldered edges 1094. The location of the cut-outs 1072 match the location of the fingers 1068 when the finger's end surfaces 1069 are adjacent to the plate 1035. Furthermore, the cut-outs 1072 are slightly larger than the finger's end surfaces 1069 (without the shouldered edges 1094) so that the fingers 1068 can reciprocally slide through the cut-outs 1072, and thus through the plate 1035.

The piston valve plug 1026 also includes four cut-outs 1075 therethrough which also have the same general shape as the shaft finger's end

surfaces 1069. The location of the cut-outs 1075 match the location of the fingers 1068 when the finger's end surfaces 1069 are adjacent to the plug 1026. The cut-outs 1075 are slightly larger than the end surfaces 1069 to allow the end surfaces 1069 to fit snugly therein. The cut-outs 1075 function as attachment locations for welding or mechanically staking the fingers 1068 to the plug 1026. During valve assembly, the shaft's fingers 1068 are slid through the plate 1035. Then, the end surfaces 1069 of the shaft's four fingers 1068 are welded or mechanically staked to the piston valve plug 1026 at the cut-out locations 1075. The shouldered edges 1094 of the finger' end surfaces 1069 prevent the fingers 1068 from pushing through the cut-outs 1075 and facilitate attachment of the fingers 1068 to the plug 1026.

The valve 1000 is biased in the first position (i.e., valve "open" or unrestricted/unblocked state) by the biasing spring 1070. In this position, the force of the spring 1070 biases the reciprocating shaft 1024 in its rightmost position within the housing bore 1030. The length of the shaft 1024 and valve housing 1020 is such that in the first position, the shaft 1024 is fully retracted into the housing 1020 and the inner facing surface of the plug 1026 lies adjacent to the outer facing surface of the housing plate 1035, and in the second position, the outer facing surface of the plug 1026 lies adjacent to far wall 1071 of the first passageway 1048. Also, in the first position, the piston 1022 is in its rightmost position within the bore 1030, and in the second position, the piston 1022 is in its leftmost position within the bore 1030. In the embodiment shown in Fig. 25, the bore 1030 includes a small amount of space, labelled as chamber 1074, between the piston's right outer facing surface 1052 and the bore's far end 1034.

To move the valve 1000 from its first position to its second position, the valve associated with the inlet fluid injector of the pair of hydraulic fluid injectors 1010 is opened in response to a control signal from an ECU (not shown). Simultaneously, the valve associated with the outlet fluid injector of the pair of fluid injectors 1010 is closed. Pressurized hydraulic fluid from the

fluid inlet be 1012 flows through the inlet fluid injector of the pair 1010, through the mbe 1028 and into the chamber 1074, where it pushes against the piston's rear outer facing surface 1052. When the fluid pressure against the piston's rear surface 1052 exceeds the opposing force of the biasing spring 1070, the piston 1022 moves to the left, pushing the shaft 1024 along with it until the piston 1022 and the shaft 1024 reach the second position shown in phantom. This movement causes the shaft's fingers 1068 to move into the first passageway 1048, thereby partially restricting the flow of TCF therethrough. Fig. 25 represents unrestricted flow of TCF through the first passageway 1048 by straight arrow lines and represents restricted flow by dashed squiggly arrow lines. When the valve 1000 is in the second position, the flow of TCF is only partially restricted because the TCF can still flow through the shaft's cut-outs 1072 (i.e., between the fingers 1068) and/or around the shaft 1024. The percentage of restriction flow is determined by a plurality of factors, including the following four factors:

1. The total area of the cut-outs 1072.

2. The total number of valves 1000 in the first passageway 1048.

3. The extent that the shaft 1024 projects into the first passageway 1048. 4. The area, if any, between the outer circumferential surface of the shaft 1024 and the inner circumferential wall of the first passageway 1048 when the valve 1000 is in the second position.

If the valve 1000 is employed as a two-position valve which is either in a first or second position, only the first two factors will be relevant to the percentage of restriction.

After the valve 1000 is placed in the second position, the hydraulic fluid in the chamber 1074 remains trapped therein because the only outlet passageway, the valve of the outlet hydraulic fluid injector of the pair

1010 is closed. Thus, the shaft 1024 will remain in the second position as long

as the states of the fluid injector valves are not changed. The O-rings 1054 prevent the hydraulic fluid in the chamber 1074 from leaking out into other parts of the housing bore 1030, while also preventing the TCF (which may find its way into the housing bore 1030 and hollow shaft 1024 through the plate's cut-outs 1072) from leaking into the chamber 1074.

When it is desired to close the valve 1000, those steps are reversed. That is, the ECU sends a control signal to the solenoid of the inlet hydraulic fluid injector in the pair 1010 to close the injector's valve. Simultaneously, the ECU sends a control signal to the solenoid of the outlet hydraulic fluid injector of the pair 1010 to open that injector's valve. The pressurized hydraulic fluid inside the chamber 1074 flows out through the housing's opening 1036, into the mbe 1028, through the open valve of the outlet hydraulic fluid injector and into the fluid reservoir 1018. As the hydraulic fluid empties out of the chamber 1074, the biasing spring 1070 pushes the shaft 1024 and piston 1022 to the right and back into the first position, thereby causing the shaft's fingers 1068 to retract out of the first passageway 1048.

The chamber filling and emptying procedure is the same as described above with respect to the EETC valves. For brevity's sake, this procedure is not repeated herein. However, it should be understood that the valve 1000 shown in Fig. 25 is only one of a plurality of similar valves which are all connected to a single pair of hydraulic fluid injectors 1010. Only a single pressure sensor is required for each grouping of valves connected to a common pair of injectors 1010. Thus, the valve 1000 shown in Fig. 25 relies upon a pressure sensor in another valve in this grouping for a measurement of its chamber pressure. Since the mbe 1028 is in fluid communication with the other valve chambers, it is also in fluid communication with that pressure sensor. If it is desired to operate the valve 1000 in Fig. 25 independent of other valves, a pressure sensor and separate pair of injectors 1010 would be associated with the valve 1000.

Fig. 27 is a sectional view of the valve 1000 in Fig. 25, taken along line 27-27 in Fig. 25. This view shows, from the center outward, the housing plate 1035, biasing spring 1070, four shaft fingers 1068, housing 1020, bolts 1042 and solid wall 1046. Fig. 28 is a sectional view of the valve 1000 in the second position shown in Fig. 25, taken along line 28-28 in Fig. 25. However, the valve 1000 represented by Fig. 28 has an oval shaped plug 1026' instead of the round plug shown in Figs. 25 and 26. This view shows, from the center outward, the four shaft fingers 1068, plug 1026' and passageway far wall 1071. Fig. 28 highlights an important feature of the invention, that the plug 1026' can be shaped and sized to seat against a far wall 1071 having any shape or size.

That is, the plug 1026' can have any desired footprint. Thus, although the plug

1026 shown in Figs. 25 and 26 is a cylindrical disk, it need not have that shape.

Water jacket passageways and TCF passageways around an intake mamfold typically include odd shaped bends, curves and the like which cannot be easily dead headed or blocked by simple-shaped plugs. The novel valve 1000 described herein accepts an infinite variety of plug sizes and shapes, as long as the plug 1026 includes a region for welding or mechanically staking the end surfaces 1069 of the shaft's four fingers 1068 thereto. Fig. 29 shows a sectional side view of valve 1000' mounted to solid wall 1046' in first passageway 1048'. Fig. 29 illustrates how the valve 1000' can be employed for the dual function of restricting the first passageway 1048', while simultaneously dead heading or blocking a second passageway 1076. This embodiment of the restrictor/shutoff valve is not controlled by remote pairs of fluid injectors. Instead, the fluid injectors are attached to housing 1020' in a manner similar to the integral fluid injectors associated with the EETC valves 500 and 600. In the section shown in Fig. 29, one of the pair of fluid injectors 1010' (the inlet injector) is visible. Fig. 29 also shows fluid pressure sensor 1090' for detecting the fluid pressure in the valve chamber

1074'. The valve 1000' also includes an optional opening 1092' for allowing the pair of fluid injectors 1010' to be in fluid communication with chambers of other valves 1000 or 1000'. In this manner, the pair of fluid injectors 1010' controls the state of these other valves. In Fig. 29, the first and second positions of the valve 1000' are represented by solid and phantom lines, in the same manner as shown in Fig. 25. When the valve 1000' is in the first position, both passageways are unblocked and unrestricted by the valve's shaft 1024. When the valve 1000' is in the second position, the first passageway 1048' is restricted by the shaft's fingers 1068 and the second passageway 1076 is blocked by the plug 1026.

Alternatively, the plug 1026 may have openings (not shown) therethrough to allow a portion of the TCF in the second passageway 1076 to pass into the first passageway 1048'. In this embodiment, the valve 1000' functions as a restrictor/restrictor valve (i.e., it restricts, but not block the flow of TCF in the first and second passageways).

The major purpose of the restrictor/shutoff valves 1000 are to block or reduce the flow of TCF through TCF passageways. As shown in Fig. 29, the novel valve 1000 can simultaneously restrict flow through one passageway, while blocking or dead heading flow through a different passageway. This simultaneous restricting/dead heading function is particularly useful when one or more valves 1000 are employed in the engine block water jacket to selectively control flow of TCF through "interior" and "exterior" water jacket passageways. "Interior" passageways, as defined herein, are those which are associated with interior most regions of the engine block water jacket, whereas "exterior" passageways, as defined herein, are those which are associated with exterior most regions of the water jacket. In a typical engine, the interior passageways are closest to the engine's moving parts. Consequently, those passageways are typically closest to the oil lines which lubricate those moving parts and are closest to the hottest parts of the engine block.

Page 111 of the Goodheart-Willcox automotive encyclopedia, The Goodheart-Willcox Company, Inc. , South Holland, Illinois, 1979, notes that the heat removed by the cooling system of an average automobile at normal speed is sufficient to keep a six-room house warm in zero degree Fahrenheit (-17.8°C) weather. Although this passage refers to an operating mode where the thermostat is open and flow to the radiator is permitted, it is clear that tremendous quantities of heat energy are generated by an average automobile, even when the coolant is not hot enough to open the thermostat. Internal combustion engines manufactured today fail to take full advantage of such heat energy, especially in cold ambient temperamre environments.

In such cold ambient temperamre environments (e.g., sub-zero temperamres [below -17.8°C]), it is most important to retain heat energy in the interior passageways to keep the oil temperature within its optimum range. It is also desirable to remove some heat energy from the interior so that the heater/defroster and intake mamfold receive some warm or hot TCF. Furthermore, it is desirable to reduce the heat energy loss from the exterior passageways so that valuable heat energy from the engine block is not wasted to the atmosphere. The valve 1000 is ideally suited to perform this task.

Fig. 30 is a simplified diagrammatic sectional view of the water jacket in engine block 1078 showing two interior passageways 1080, two exterior passageways 1882 and valves 1000,, 1000 ₂ for respectively dead heading and restricting those passageways. That is, each valve 1000, and 1000 ₂ blocks flow through an exterior passageway 1082 and simultaneously restricts flow through an interior passageway 1080. In the embodiment shown in Fig. 30, the valve 1000, blocks flow through the lower exterior passageway, whereas the valve 1000 ₂ dead heads the flow through the upper exterior passageway. As noted above, dead heading the flow allows the TCF fluid trapped in the passageway to function as an insulator, further reducing undesired heat energy loss from the engine block 1078 to the ambient environment.

Fig. 30 thus shows how the valve 1000' shown in Fig. 29 is employed in a water jacket wherein the first passageway 1048' is equivalent to an interior passageway and the second passageway 1076 is equivalent to an exterior passageway.

Some of the preferred materials for constructing the restrictor/shutoff valve and operating parameters were described above. In one embodiment of the invention, the following materials and operating parameters were found to be suitable.

Biasing spring - stainless steel

Valve housing - aluminum die casting - machined or stainless steel sheet metal

Shaft, plug - powdered metal or aluminum die cast

Piston/shaft stroke - aluminum die casting - machined or stainless steel sheet metal

Flow restriction - variable from about 50 percent to about 100 percent

Although the pair of hydraulic fluid injectors 1010 associated with the restrictor/shutoff valves may be similar to the injectors 18, 20, the preferred inlet fluid injector will most likely require a larger flow capacity than the inlet fluid injector 18. Likewise, the fluid inlet mbe 1012 will also most likely require a larger flow capacity than the fluid inlet mbe 36 associated with the injector 18.

The larger flow capacity may be required because the restrictor/shutoff valve will usually be operated (i.e. , moved into a restricted or blocked position) in much lower ambient air temperamres than the EETC valve. If engine lubrication oil is employed as the hydraulic fluid, such oil will have a higher viscosity in a cold temperamre environment. When the oil is thick and slow flowing, the valve chamber will fill more slowly than when the oil is at a

higher temperamre, and thus at a lower viscosity. If the ambient air temperamre is very low (e.g., sub-zero degrees Fahrenheit [below -17.8°C]), the filling time could become unacceptably long. By increasing the flow capacity through the inlet injector and into the chamber, the filling time is decreased to compensate for the higher viscosity oil.

To increase the flow capacity through the inlet fluid injector when employing a fluid injector such as the DEKA Type II injector shown in Fig. 16A, the orifice 710 should be increased. Also, the lift of the needle valve 706 should be greater. The greater lift will probably require a greater capacity solenoid 704.

The outlet fluid injector associated with the restrictor/shutoff valve is only opened when the valve is moved into an unrestricted or unblocked position. Since this will normally occur only after the engine has warmed up and the oil viscosity has decreased, this injector and its associated outlet tube need not necessarily be designed to handle a greater flow capacity. Likewise, since the chamber of the EETC valve is filled (thereby allowing TCF fluid flow to the radiator) only when the engine and engine oil are relatively hot, the injectors 18, 20 will usually not encounter this flow capacity problem either.

The slow filling of the valve chamber caused by high oil viscosity will not be a problem in prolonged extremely cold temperamre environments (e.g. , prolonged sub-zero degree Fahrenheit [below -17.8°C] temperatures). In such conditions, it is entirely possible that the restrictor/shutoff valve will remain in a restricted or blocked position for days or weeks at a time without being moved into its unrestricted/unblocked state. The restrictor/shutoff valves can be employed in an anticipatory mode to lessen the sudden engine block temperature peaks caused when a turbocharger or supercharged is activated, in the same manner as the anticipatory mode described above with respect to the EETC valves. When the turbocharger or supercharger is activated, a signal can be immediately delivered to the restrictor/shutoff valves to cause the valves to be placed in their

unrestricted/unblocked state, if they are not already in that state. A short time after the turbocharger or supercharger is deactivated, the valves can then be returned to the state dictated by the ECU.

In extremely hot ambient air conditions, a system wherein the states of the EETC valve and restrictor/shutoff valves are controlled according to one or more of the curves will perform better upon engine start-up than a cooling system having a thermostat controlled solely by coolant temperamre. This is because the curves allow the designer to anticipate expected engine operating conditions based on the present TCF and ambient air temperamre. Accordingly, the EETC valve can be immediately opened and the restrictor/shutoff valves can be immediately placed in an unblocked/unrestricted state in anticipation of an expected engine operating condition that would call for such states.

Consider a prior art vehicle which has been sitting in the sunlight when the ambient air temperamre is 100 degrees Fahrenheit (37.8°C). In such an environment, the underhood and vehicle interior is likely to be at least 120 degrees Fahrenheit (48.9°C). The coolant temperamre will likely be at least 100 degrees Fahrenheit (37.8°C). When the driver enters the vehicle and starts the engine, the air conditioning is typically immediately turned on to its maximum setting. Due to the hot conditions and the extra stress on the engine due to the air conditioning system, the coolant temperamre quickly rises. Although it is virtually certain that the coolant will need to flow to the radiator to keep the engine block at an optimal operating temperamre, the thermostat must nevertheless wait until the temperamre has reached the appropriate level before it opens to allow flow to the radiator. The result is that full engine cooling is temporarily delayed. If the vehicle is equipped with a prior art wax pellet type or bimetallic coU type thermostat, there will an even greater delay before the coolant can flow to the radiator due to thermostat hysteresis. These delays may cause a sudden engine block temperamre peak which, in turn, may

cause the coolant temperamre and engine oil temperamre to temporarily reach levels which exceed the ideal range.

However, if the vehicle is equipped with a novel EETC valve and restrictor/shutoff valves controlled by the programmed curve, all of the TCF will immediately flow through the radiator upon engine start-up. Accordingly, the likelihood of a sudden engine block temperamre peak will be reduced. This is because the curves shown in Figs. 19, 20, 22A and 22B indicate that at an ambient temperamre of 100 degrees Fahrenheit (37.8°C) and a TCF temperamre above 100 degrees Fahrenheit (37.8°C), the EETC valve should be in the open state and the restrictor/shutoff valve should be in the unblocked/unrestricted state. Of course, there will be a two or three second delay before the valves can be placed in these states after starting the engine to allow the hydraulic fluid system to reach proper operating pressure. This anticipatory feature is an inherent benefit of controlling the state of a flow control valves according to a programmed curve.

A problem may occur after the engine has been shut-off if the hydraulic fluid does not fully drain out of the hydraulic tubes 36, 38 and back into the reservoir. As a consequence, if the engine is in an environment where the ambient temperamre is very cold, the viscosity of the fluid that remains in the tubes may increase such that the fluid becomes thick (e.g., molasses-like). When the engine is subsequently turned on and a signal is sent to actuate the EETC valve 10, the thick fluid may lengthen the time required to fully actuate the valve to change its state. Accordingly, the engine wiU not be operating as efficiently as desired. In extreme conditions, the fluid may become so thick so as to completely inhibit the actuation of the EETC valve.

In order to address this problem, the present system "dithers" the solenoids. That is, the engine control unit (ECU) 900 determines when the engine has shut-off, at which point control signals are sent to the solenoids. The control signals result in the solenoids causing the injectors to "open" and "close" a series of times. Each time the injector opens, the upper end of the

fluid mbe is exposed to air pressure in the EETC valve. The air pressure, working in combination with the force of gravity, causes the fluid in the mbe to retreat back into the reservoir. The dithering will even work on the fluid input mbe 36 which is normally filled with pressurized hydraulic fluid because, with the engine shut-off, pressure is no longer being supplied to the hydraulic fluid in the inlet mbe 36. Accordingly, opening the hydraulic injector 18 associated with the fluid inlet mbe 36 will not result in fluid entering passage 76 but, instead, will result in the air pressure from passage 76 entering the fluid inlet mbe 36 causing the hydraulic fluid in the line to retreat to its starting point, e.g., oil pump.

An example of the dithering process is as follows. After the ECU 900 determined that the engine is shut-off, the ECU sends signals to the solenoids controlling the fluid injectors in communication with the fluid inlet and outlet tubes 36, 38. The signals direct the fluid injectors 18, 20 to open and close a predetermined number of times or according to a preprogrammed schedule. This causes air pressure from the passage 76 to enter the fluid inlet and outlet tubes 36, 38 which, acting in combination with the force of gravity, causes the fluid in the lines to return to their respective reservoirs (e.g. , oil pump 94, oil pan 90). It is preferable to dither the solenoids while the hydraulic fluid is still sufficiently warm since the viscosity of hydraulic fluid increases as its temperamre decreases. Hence, when the hydraulic fluid is very warm, the dithering of the solenoids will allow the hydraulic fluid to naturally and readily flow back to its reservoir. If the dithering occurs after the hydraulic fluid has cooled, the higher viscosity of the hydraulic fluid will likely slow down its natural flow back into the reservoir. That is, the viscosity of the hydraulic fluid may increase such that the force of gravity and the pressure created by the dithering may not be sufficient to drive the fluid back into the reservoir. Accordingly, it is preferred that the dithering occur soon after the engine ignition has been turned off.

A variety of different techniques for dithering the solenoids may be practiced within the scope of this invention. For example, it may be desirable, depending on the configuration of the system, to open both hydraulic injectors simultaneously and hold them in the open position for a sufficient amount of time to permit the fluid to return to the oil pan. Alternately, and more preferably, it is desirable to open and close the injectors in a 50% duty cycle (i.e., 50% off/50% on). This is equivalent to a step function map or schedule which is, preferably, programmed into the memory of the ECU 900. The amount of cycles, the length of time that a injector is open, and the total duration of the dithering will vary depending on the system configuration (e.g. , diameter of fluid mbe, length of fluid mbe, type of fluid utilized, etc.). Additionally, other scheduling functions may be utilized, e.g. sinusoidal, linear, logarithmic, exponential, etc. In a GM 3800 V6 transverse internal combustion engine, it has been found that dithering the injectors in a 50% duty cycle for between 5 and 30 seconds and at about 6 Hz is sufficient. More preferably, the dithering is performed for a total time of 10 seconds.

Referring now to Fig. 35A, a flow chart is shown depicting one embodiment for controlling the dithering of the hydraulic injectors. The subroutine begins by determining whether the engine ignition has been turned off. Since the dithering of the valves should only be accomplished when the engine is no longer running, this step determines when dithering is needed. In order to determine whether the ignition is on or off, the ECU 900 receives engine operating state parameters (shown in Fig. 17). A variety of signals may be utilized to determine if the engine is running, such as an ignition signal, a signal from the distributor, the engine RPM, or the engine manifold vacuum.

Once it has been determined that the engine is no longer running, the system can begin to dither the solenoids. This is accomplished by starting a timer and sending signals to the hydraulic solenoid injectors 18, 20 to open and close according to a predetermined schedule. As stated above, the predetermined schedule may simply comprise an oscillating step function curve.

The dithering is continued until the timer expires whereupon the subroutine ends. The amount of dithering time required is empirically determined and, as stated above, depends on the configuration of the system. The predetermined schedule for controlling the dithering is also empirically determined based on the system configuration.

In an alternate embodiment not shown, the timer is eliminated and, instead, the predetermined schedule would control the duration of the dithering. That is, the injectors are opened and closed according to the preprogrammed schedule. Once the program schedule is complete, the dithering ends.

In the above example, the dithering was initiated immediately after the engine was shut-off. However, it is also within the purview of this invention to control the point at which the dithering of the injectors begins. That is, it is not necessary, and in many cases not preferable, to automatically dither the injectors upon engine shut-off. For example, after engine ignition shut-off, the system continuously monitors the temperamre of the hydraulic fluid. When it is determined that the temperamre of the hydraulic fluid has fallen below a predetermined threshold valve, T ₀ , which is chosen to be indicative of a relatively warm, low viscosity hydraulic fluid state, the system begins to dither the injectors to remove any hydraulic fluid in the tubes. This embodiment of the invention eliminates unnecessary actuation of the injectors and, therefore, does not needlessly reduce the operational life of the injector.

An alternate and more preferred embodiment of the invention is illustrated in Fig. 35B. In this embodiment, the system determines when the engine has been shut-off as described above. The system then determines whether the valve, which is this case is the EETC valve, is open or closed. If the valve is closed, i.e., inhibiting TCF flow to the radiator, the system begins to dither the solenoids/injectors as discussed above. If the valve is not closed, i.e., the valve is open, permitting TCF flow to the radiator, then the system

continuously monitors the valve state to determine when it closes, at which point the dithering of the solenoids commences.

This preferred embodiment of the dithering system is related to the "hot engine off soak" described above. More specifically, after the system determines that the engine has been shut-off, it then determines the state of the valve 40 by comparing the sensed temperamre control fluid and ambient air temperamres to the predetermined temperamre control curves, such as those discussed above and shown in Figs. 19 and 20. If the valve state is "open" according to the curves, the system keeps the injectors closed, continuing to trap the hydraulic fluid in the upper chamber 58 of the EETC valve 10, and thereby maintaining the flow path to the radiator. After the sensed TCF and ambient air temperamres have changed so as to define a "closed" valve state according to the temperature control curves, the ECU 900 sends a signal to open the fluid injector 20 in communication with the fluid outlet mbe 36 permitting the upper chamber 58 to empty. The ECU 900 then sends a sequence of signals to the fluid injectors 18, 20 to begin dithering in accordance with a predetermined schedule.

This embodiment provides the greatest benefit in engines that are frequently shut-off for only short periods of time before being restarted, such as delivery vans in urban environments. During these short periods of shut-off, the temperamre of the hydraulic fluid in these engines is not likely to fall below the temperature at which the viscosity begins to become excessive. Accordingly, there is no need to dither the hydraulic injectors unless it is determined that the engine is beginning to cool significantly. Additionally, when the engine is restarted and whUe the hydraulic oU is very hot, it is preferable that the temperature control fluid be allowed to circulate through the radiator for cooling. Hence, maintaining the EETC valve in its open position after the engine is initially shut-off permits this desired result to be immediately achieved without the delay associated with the actuation of the valve.

P 8640

72

While the above embodiments have been directed, primarily, to the dithering of the solenoids associated with valves such as the EETC valve 10, the invention also encompasses the dithering of the hydraulically actuated restrictor/shut-off valves discussed above. However, after the engine ignition is shut-off, if it is determined that the restrictor/shut-off valves are in the actuated position such that the flow of TCF is restricted in the water jacket, then it is preferable that the solenoids associated with the restrictors/shut-off valves and not be dithered regardless of the temperamre of the hydraulic fluid. The primary intent with this embodiment of the invention is to prepare the engine for start-up. That is, if it is determined that the restrictor/shut-off valves are actuated just prior to engine ignition shut-off, then it is likely that the engine is relatively cold (i.e., below its optimum operating temperature) and, accordingly, the valves are restricting the flow of TCF through the water jacket in order to increase the engine temperamre. Therefore, since the temperamre of the engine would not likely have risen after it was shut- off, upon restarting the engine will need to be heated up as quickly as possible to bring it to its optimum operating temperamre. In order to achieve this, the restrictor/shut-off valves should be in their actuated (restricted) position. Hence, by preventing dithering of the injectors in the restrictor/shut-off valves when they are already actuated, the system assists in preparing the engine for restarting.

It should be apparent that, in this embodiment of the invention, if the restrictors are already actuated, the viscosity of the hydraulic fluid in the lines leading to and from the restrictor/shut-off valves is of no concern at restarting. Additionally, based on the temperature control curves, the hydraulic fluid will be at a significantly higher temperamre (and lower viscosity) when it becomes desirable to retract the restrictor/shut-off valves.

If the restrictor/shut-off valves are not actuated (unrestricted flow position) when the engine is shut-off, then the temperature of the TCF at shut- off is relatively hot. When the engine is later restarted, it is preferable that the

restrictor/shut-off valves be actuated immediately to reduce the flow of TCF and, thereby, heat up the engine quicker. In order to prepare the restrictor/shut-off valves for immediate actuation, the present invention dithers the valves in a similar fashion to the embodiments described above for the EETC valve. This will minimize any delay in the actuation of the valves caused by the high viscosity hydraulic fluid.

Figure 35C illustrates a flow chart of the preferred embodiment for dithering the restrictor/shut-off valves.

It should be noted that in the above embodiments directed to the EETC valve, the "open" position or state (permitting TCF flow to radiator) of the valve corresponds to the "actuated" position of the valve wherein the hydraulic fluid fills the chamber 58. However, it is well within the purview of this invention to encompass an embodiment wherein the "actuated" position of the EETC valve corresponds to the "closed" position of the valve (inhibiting TCF flow to radiator). In such an embodiment, the dithering of the valve would be similar to the restrictor/shut-off valve. More specifically, if the valve is actuated in the closed state when the engine is shut-off, (inhibiting TCF flow to the radiator), then the temperamre of the TCF is relatively low. In this condition, the solenoids on the EETC valve are not dithered after engine shut- off and the hydraulic fluid is kept trapped in the chamber 58 so as to maintain the valve in the actuated (closed) position. If, on the other hand, the valve is open (unactuated) after engine shut-off (permitting TCF flow to the radiator), then the temperature of the TCF is relatively hot and, therefore, it is preferable to dither the solenoids after engine shut-off to remove the hydraulic fluid in the lines. More preferably, the dithering occurs after the valve closes in accordance with the "hot engine off soak" described above.

Although the EETC valves disclose fluid injectors which are integrated into the valve housing, the scope of the invention includes an embodiment wherein the fluid injectors are physically separated from the reciprocating EETC valve components and connected by fluid lines

therebetween. Likewise, the fluid injectors associated with the restrictor/shutoff valves can be either integrated into the valve housing as shown in Fig. 29, or can be physically separated from the reciprocating valve components as shown in Figs. 24 and 25. Alternatively, fluid injectors associated with an integrated valve such as shown in Fig. 29 can control the state of other restrictor/shutoff valves which do not have their own fluid injectors.

The inlet hydraulic fluid injector employed in the novel EETC and restrictor/shutoff valves must tap into a source of pressurized hydraulic fluid to fill the respective valve chambers. Typical valves will tap into that source for about six seconds to fully change state. A slightly longer time period may be required for systems where a single injector fills the chambers of multiple restrictor/shutoff valves. These time periods are very short compared to the average length of a vehicle trip. Since valve states are unlikely to be changed more than a few times during a normal vehicle trip, the percentage of time that the pressurized source is tapped is anticipated to be very small, typically under one minute for every hour of driving, or less than 2%. Accordingly, there should be little, if any, effect on the normal functioning of the hydraulic fluid system. Thus, if the engine lubrication oil pump outlet lines are the source of the hydraulic fluid, the operation of the novel valves should not have any significant effect on the normal operation of the lubrication system. Nor should it be necessary to modify existing oU pumps or lubrication systems to accommodate the novel valves.

The novel EETC and restrictor/shutoff valves described above reciprocate between a first position for allowing unrestricted flow of fluid through at least one passageway and a second position for restricting the flow through the passageway. The flow restriction is either partial or complete (i.e. , 100 percent). Each of the valves are biased in one of the positions by a biasing spring and placed in the other position by hydraulic fluid pressure pushing against a piston member. In the EETC valves, the piston member is either a

diaphragm or a piston shaft. In the restrictor/shutoff valve, the piston member comprises a combination of a separate piston and shaft.

Although the EETC and restrictor/shutoff valves are shown as having a first position associated with a pressurized, fully filled chamber and a second position associated with an unpressurized, empty chamber, each of the valves can be designed to operate in reverse. That is, the position of the chambers and biasing springs can be reversed so that the valve is in a first position when the chamber is unpressurized and empty and is in a second position when the chamber is pressurized and fully filled. The scope of the invention includes such reversed configurations.

Likewise, the scope of the invention includes embodiments wherein the EETC and restrictor/shutoff valves are placed in positions between the first and second positions by only partially filling and pressurizing the respective chambers. To achieve a desired mid-position for a particular valve, chamber pressure values and/or filling or emptying time periods must be empirically determined for that valve. For example, if a particular EETC valve is fully opened by pressurizing the chamber to 25 psi~(172 kPa) and continuing to pressurize for two seconds after the chamber reaches 25 psi (172 kPa), a procedure of pressurizing until the chamber reaches 15 psi (103 kPa) might place the valve in the desired mid-position. Alternatively, if it is desired to move an open EETC valve to a mid-position, partial chamber depressurization could be employed. Again, the particular pressure values and additional time periods must be empirically determined for a given novel valve. Once those values are determined, the ECU can be pre-programmed with the values to achieve the desired mid-position(s). Alternatively, a feedback control system employing valve position transducers connected to the ECU could be employed.

The present invention provides additional consequential benefits.

By providing the means to increase the actual temperature of the TCF fluid in cold temperature environments (see Fig. 23), the physical size of the heater can be decreased. This is because the hotter the temperature of the TCF, the less

heater core surface area is required to extract the necessary amounts of heat energy from the TCF to warm the vehicle's passenger compartment.

An engine employing the EETC valve and one or more restrictor/shutoff valves will have less engine out exhaust emissions and greater fuel economy than a prior art engine cooling system employing only a prior art thermostat. Since the reduction in emissions and improvement in fuel economy will be greatest in cold temperature environments and during engine start-up, the invention offers the possibility to significantly reduce vehicle exhaust pollution levels. Currently, the United States Environmental Protection Agency conducts its emissions testing in relatively warm ambient air temperamres. Testing in these warm temperamres does not expose the actual polluting effects of vehicles when they are started and operated in cold temperature climates. For example, the current testing procedure requires that a vehicle "cold soak" in an ambient air temperamre of 68 to 80 degrees Fahrenheit (20 to 26.7 degrees Celsius) for 12 hours. That is, the vehicle must sit unused for 12 hours in this temperamre environment so that the engine parts stabilize to that ambient air temperamre. Then, the engine is started and emissions are measured to verify that they are within acceptable limits. Since the ambient air temperamre is relatively warm, the engine and catalytic converter quickly heat up to an efficient operating temperamre. Most vehicles today would fail the current emissions standards if the "cold soak" test was required to be performed in significantly lower ambient air temperamres, such as 28 to 40 degrees Fahrenheit (-2.2 to 4.4 degrees Celsius). An engine employing the EETC valve and one or more restrictor/shutoff valves will show a substantial improvement over current systems towards meeting current emissions standards under a "cold soak" test at such lower ambient air temperamres.

The inventions disclosed above provide an effective way to harness the underestimated one-third of heat energy handled by a vehicle's cooling system (see the exceφt in the Background of the Invention from page

111 of the Goodheart-Willcox automotive encyclopedia). The EETC valve, the restrictor/shutoff valve, and the use of programmed curves for determining their states are the basic building blocks for an engine temperamre control system that effectively tailors the performance of the engine cooling system with the overall needs of the vehicle.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.