Reference To Related Applications

This is a continuation in part application of my two prior pending patent applications, U.S. application Serial No. 381,197 filed July 18, 1989, for an invention titled HYDROSTATIC POWER TRANSFER SYSTEM and U.S. application Serial No. 414,254 filed September 29, 1989, for an invention titled ACTIVE ACCUMULATOR VIBRATION ABSORBING SUPPORT SYSTEM.

Technical Field This invention relates to a power transfer system for vehicles. My application Serial No. 381,197 relates to a hydrostatic power transfer system which utilizes an active pressure accumulator interposed between the vehicle engine and hydraulic drive motor(s) for the drive wheels of the vehicle. This arrangement provides for an effective vibration isolation of the vehicle engine and pump driven thereby from the hydraulic motors for the vehicle drive wheels.

My prior application serial No. 414,254 relates to the use of a pressure accumulator for supplying fluid pressure for active vibration isolation mounts, such as engine mounts and the like.

The present invention is directed toward improving upon the systems of my above two mentioned prior applications, including utilization of an active pressure accumulator for additional functions on a vehicle.

Background Art

In typical motor vehicle operations, the vehicle engine must drive many auxiliary systems in addition to providing power to the power train which eventually

drives the propelling wheels of the vehicle. For example, with water cooled engines, a water pump is connected by a belt or chain drive to the engine crankshaft. Additionally, the engine oil lubrication system pump is driven directly from the vehicle engine. Further, an electric power generator is powered by the engine with a chain or belt drive connection to the engine crankshaft. Other auxiliary systems that are powered by the vehicle engine include ABS braking systems, air conditioner compressors, and windshield wiper driver motor systems and other auxiliary systems.

The driving connection of these auxiliary systems to the vehicle engine, all require some type of mechanical drive train connection between the engine crankshaft and the auxiliary system pump or motor. Each of these drive trains involve energy losses in the engine and units of the drive trains and also provide for the transfer of torque, pulsations, and vibration, between the engine and the auxiliary system pump(s) or motor(s) being driven thereby. Such torque, vibration, and noise transfer in the drive trains between the engine and the auxiliary systems may result in bearing wear problems and generate vibrations which are transferred not only to the engine and the auxiliary systems, but also to the vehicle frame, causing vehicle noise problems, as well as wear problems on the entire vehicle system. Furthermore, since the auxiliary systems operate with varying load demands on the engine such as caused by the switching on and off of a vehicle air conditioning compressor drive motor in response to the air conditioning needs of the vehicle, there are frequently occurring transient start-up and shut-down phases for each of the auxiliary systems, which when they coincide with one another, cause major fluctuations in required engine

torque as well as in torque feedback to the engine from the auxiliary systems.

Furthermore, the varying loads imposed by the operation of the auxiliary systems necessarily require varying engine torque output demands on the engine, thereby requiring the engine to operate over a range of different speed and torque values. Optimum engine efficiency may be realistically designed for only a very narrow engine speed and torque range. Such fluctuating loads inherently adversely affect the vehicle engine operating efficiency due to the requirement to design the engine to operate over wide engine speed and torque ranges.

Disclosure Of Invention

An object of the invention is to provide improved power transfer systems for vehicles which provide for the smooth and efficient operation of vehicle auxiliary devices, while minimizing wear and tear on the vehicle engines. This and other objects are achieved according to preferred embodiments of the present invention by providing that, rather than coupling the auxiliary systems to the engine directly, they are driven by fluid pressure from a hydraulic fluid accumulator, which accumulator in turn is maintained as a continuously active accumulator at a constant required pressure by means of a pump driven by the engine. In especially preferred embodiments, the pump and engine are designed so as to provide the maximum required accumulator pressure and volume, with the consequence that the engine and pump can be designed to operate very efficiently over a desired narrow speed and torque range. A microprocessor control unit is provided for controlling a manifold valve interposed between the pump and the active accumulator so as to maintain the

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desired pressure in the accumulator system. The auxiliary system motor(s) and pump(s), such as the water pump, oil pump, air conditioner compressor motor, and the like are all driven by the fluid pressure from 5 the active accumulator but with the control unit operating to control manifold valves interposed between the accumulator and each of these respective auxiliary drive motors and pumps.

In certain preferred embodiments, where the

10 pressure required for the auxiliary system is substantially lower than the maximum pressure maintained in the main accumulator, capillary tubes are interposed so as to provide automatically for a pressure reduction between the auxiliary system and the

15 main pressure accumulator.

In especially preferred embodiments, the control unit is provided with auxiliary system operating condition signals representative of the auxiliary system hydraulic pressure power needs, and the control

20 unit then controls the manifold valve between the main accumulator and the respective auxiliary unit to provide the desired fluid pressure and fluid volume.

In certain preferred embodiments, the engine or other power source is permanently connected to the main

25 pump via a shaft or constant velocity universal joint, such that no shiftable transmission is required between the engine and the main pump, thereby providing for a smooth, quiet, hesitation-free drive of the pump. The interposition of the constantly active accumulator

30 between the vehicle wheel drive systems and the auxiliary systems effectively isolates the transfer of any vibrations, torque and noise between the engine and pump and these auxiliary systems. Since the main pressure accumulator is maintained at substantially

35 constant pressure and acts as a ^M source" of fluid

pressure for all of the connected vehicle wheel drive systems and auxiliary systems, there is minimal fluid flow velocity within the main accumulator. Thus the accumulator can be constructed of various shapes so as to accommodate space considerations within the vehicle environment. Further, since the mechanical drive train connections between the engine crankshaft and the auxiliary systems are eliminated, the entire auxiliary drive system can be readily designed to fit into the available vehicle space. Utilization of the present invention in a motor vehicle results in quiet running, hesitation free operations of the vehicle wheel driver and the drive trains for all auxiliary systems. That is, by interposing the main constantly active accumulator (and using valves and the microprocessor to control the operation of the accumulator) between the engine-pump and the rest of the drive train and auxiliary serving units of the vehicle, the vibration, torque, pulsation and noise of the engine, pump and auxiliary units are effectively prevented from being transported to the chassis and cab of the vehicle. This enables a smooth, quiet and far more efficient operation of the total vehicle as compared with known systems. Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Brief Description Of Drawing

Figure 1 is a schematic view depicting the continuously active pressure accumulator power transfer

system construction according to a preferred embodiment of the present invention.

Best Mode For Carrying Out The Invention

Figure 1 schematically depicts a continuously active pressure accumulator power transfer system constructed according to a preferred embodiment of the present invention. Referring to Figure 1, a vehicle engine 1 is provided which includes a rotatable output shaft 2 drivingly connected to pump 3. Pump 3 has its outlet connected to a control valve manifold 4 which controls the supply of pressurized fluid to a main active accumulator 5. Lines 6 and 7 represent return lines to and from a fluid system reservoir. The active accumulator 5 is maintained at a substantially constant pressure by an essentially constant velocity running engine 1 and pump 3. For this purpose, the microprocessor unit 8 is provided which includes an output control signal line 9 controlling the manifold valve 4 as a function of the pressure sensed by pressure sensor 10 and the pressure signal line 11. At least a substantial portion of the fluid in the accumulator 5 is a pressurized gas which, because of its elastic properties, acts as a shock and vibration absorber for the whole drive to avoid jerks. The active accumulator 5 is continuously communicated via main pressure output line 12 with a plurality of vehicle auxiliary units described below, as well as the vehicle wheel drive units 13. The wheel drive units 13 are controlled by the schematically shown manifold valve assemblies 14, controlled by the microprocessor line 15 as a function of the detected and desired wheel drive condition via detection line 16. The operation of the vehicle wheel drive unit 13 is described in detail in my co-pending application Serial

No. 381,197 the disclosure of which is hereby incorporated by reference. The wheel drive units 13 could also be operated in a conventional manner.

The first shown auxiliary vehicle unit 17 is a vibration isolation mount system of the type disclosed in my prior application Serial No. 414,254. The vibration isolation mounts 17 have their fluid supply controlled by the manifold valve assembly 18 and the control line 19 from the microprocessor 8, which operates in response to the detected vibration isolation mount conditions via detection line 20. The disclosure of my prior application Serial No. 414,254 is hereby incorporated by reference. It is also envisioned that other, conventional fluid pressure operated vibration isolation mount systems and suspension systems could be employed.

The engine water pump 21 is connected with the accumulator 5 via line 12 and manifold valve 22, which manifold valve is controlled via control line 23 in response to detected water pump need conditions via line 24.

The engine oil pump 25 is operatively driven by the fluid pressure from the accumulator 5 via line 12 and manifold valve assembly 26, which is controlled via control line 27 in response to detected desired oil pump conditions transmitted via line 28.

The vehicle electric generator 29 is driven via the fluid pressure from the accumulator 5 via the main pressure line 12 and the manifold valve assembly 30, which valve assembly 30 is controlled by control line 31 from the microprocessor unit 8 based upon detected generator need conditions via line 32.Some or all of the electrical units of the vehicle can be electrically powered by the generator.

The air conditioner compressor motor 33 is also driven via the fluid pressure from accumulator 5 via line 12 and manifold valve assembly 34, which valve assembly 34 is controlled via control line 35 from the microprocessing unit 8 in response to the detected and desired condition via line 36.

The ABS system 37 is supplied with operating pressure via the accumulator line 12 and manifold valve assembly 38, controlled by line 39 from the microprocessing unit 8 in response to the detected need requirements via line 40. it should be understood that an interface piston cylinder connection will be utilized in the ABS pressurizing system whenever the fluid in the ABS system is different than the active accumulator fluid.

The windshield wiper drive motor system 41 is also powered by the fluid pressure in line 12 via manifold valve assembly 42, in turn controlled by the microprocessing unit 8 in response to the detected desired condition via lines 43 and 44, respectively. It should be understood that the microprocessing unit 8 will cooperate together with any manual controls and/or other automatic controls for controlling the windshield wiper operation, the drawing really depicting the supply of pressurized fluid for the windshield wiper motor.

Although the preferred embodiment illustrated and described relates to a vehicle with a wheel drive system, it should be understood that the invention could also be implemented in conjunction with a boat, where the boat propeller drive would be substituted for the wheel drive 13. Other vehicle arrangements such as air craft and the like could also utilize the present invention according to preferred embodiments thereof.

9

Further, although vehicle environments have been described in conjunction with the preferred embodiment illustrated, the invention could also be used for certain stationary non-vehicle environments wherein similar requirements are needed for driving a plurality of auxiliary devices which exhibit varying loads on the system during operation. Also, the auxiliary vehicle units powered by pressurized fluid from the accumulator 5 could include other types of units than those shown and described, such as a small turbine or a high pressure pump whose output is in turn used to drive one or more auxiliary units.

Although the present invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.