Description of Related Art: During operation of the internal combustion engine, oil is taken from the oil pan, where it is typically stored, and circulated throughout the engine to lubricate the internal moving parts. For optimal engine operation and life, and for effective lubrication, the oil must be clean and maintain its lubricating qualities. To keep the oil free of the larger metal particles and dirt that inevitably are created and accumulate in the oil as the oil breaks down with continued engine use, the oil is typically filtered as it is circulated by a replaceable oil filter carried on the engine. Additionally, to eliminate the more minute particles and acid that builds up in the oil, which the filter cannot remove, the engine oil pan is periodically drained and replenished with new oil, and a new oil filter may be installed.

Up to half a quart of contaminated oil can remain in the oil pan after each oil change, so that even with periodic maintenance, over time an oily"sludge"is formed within parts of the engine from an accumulation of undissolved tars and insoluble particles, particularly in the oil pan. That sludge degrades engine performance, and can release particles after the oil has been replaced. The presence of those particles in the oil leads to premature engine wear.

To reach and remove accumulated sludge without disassembling the engine, an engine flushing apparatus can be used to treat the engine with a cleaning solution, circulating the cleaning fluid through the engine and oil drain pan from which the engine oil has been drained. A conduit from the flushing apparatus, typically a hose capable of withstanding high fluid pressure, is connected to the oil filter port leading to the engine's lubrication system, and another conduit is connected to the drain port at the engine's oil pan for returning the flushing fluid from the engine's lubrication system to the flushing apparatus. Since the size and type of oil filter port and oil pan drain port differs from automobile manufacturer to manufacturer and even among different models or model year of a single auto manufacturer, the flushing apparatus includes a necessary set of associated adapters to permit connection of the conduits to the respective oil filter and oil pan drain ports of the vast majority of automobile engines.

The flushing fluid is circulated from the apparatus through the oil lubrication system of the engine, where the fluid ideally dissolves the tars of the sludge and collects any undissolved particles in suspension. The flushing fluid exits the engine with dissolved sludge and suspended sludge along with undissolved particles via the oil pan drain port, through which the"dirty"flushing fluid is returned to the flushing apparatus for further processing or disposal.

The flushing apparatus ideally continues circulating the cleaning fluid for a prescribed treatment period. However, it has been found that a fundamental problem interfering with continuing circulation of the flushing fluid for the prescribed treatment period can arise when particulate matter and undissolved, suspended sludge clog the valves of conduits circulating the flushing fluid to and from the engine. Such valves are typically opened and closed during the cycling of the flushing apparatus, particularly as the flushing apparatus progresses through various stages of cleansing the oil lubrication system of the engine, allowing the solenoid valve particularly in the return line from the engine to become stuck with the suspended sludge from the engine.

In one conventional apparatus for cleaning internal oil lubrication chambers of internal combustion engines with a cleaning fluid circulated through the engine oil chambers from a cleaning fluid tank, the cleaning fluid is pumped from the cleaning fluid tank by a double diaphragm pneumatically driven pump that is energized

by an air compressor. The supply of air pressure to the pump is controlled by a solenoid valve, and the flow of cleaning fluid to and from the engine through the pump is controlled by inlet and outlet solenoid valves. Filters are provided in the return line between the pump and the cleaning fluid tank for removing dirt, oil, carbon and other undesirable material from the cleaning fluid before it is returned to the cleaning fluid tank.

However, it has been found that cleaning fluid from the engine circulating through solenoid valves, particularly through the return line, controlling the return flow of cleaning fluid, can become at least partially clogged, interfering with the operation of such a flushing apparatus. This problem has not only hampered the flushing of the internal oil lubrication passages of gasoline fueled internal combustion engines, but because the oil used in diesel engines can accumulate a thicker sludge with continued engine use, has also proved to be a significant obstacle to the successful performance of such a procedure for diesel engines.

In addition, it has been found that collection of water in the air pressure line from the compressor to the pneumatic pump due to condensation in the line can interfere with operation of the solenoid valve controlling the supply of air pressure to the pump, which can also cause an interruption of the cleaning process for clearing of the air pressure line. It would be desirable to provide a flushing system for flushing the oil circulation lubrication systems of internal combustion engines without the need for solenoid valves, that will allow for the control of the cycling of the system, such as through different cleaning stages, without clogging of the flushing fluid supply or return lines, and that would thus avoid interruption of the cycling of the system due to clogging of the flushing fluid solenoid valves or air pressure solenoid valves.

Such pneumatically or hydraulically driven pump systems also require a relatively heavy and bulky, energy inefficient air compressor system that makes it difficult to move or transport such a system. It would be desirable to provide a flushing system that is lighter and more mobile, so that it can be moved where necessary to a desired service area, that uses less power than is typically required for powering such as system with an air compressor, that can provide a continuous, even flow of flushing fluid when required. It has heretofore also been difficult to achieve any satisfactory flushing

of the internal oil lubrication chambers of diesel engines, and it would be desirable to provide a system that lends itself to flushing of the internal oil lubrication chambers of diesel engines, and particularly large diesel engines. The present invention meets these needs.

SUMMARY OF THE INVENTION Briefly, and in general terms, the present invention provides for an improved, clog resistant engine flushing system utilizing relay controlled electric pumps for flushing the oil lubrication systems of internal combustion engines. The use of relay controlled electric pumps allows the flushing apparatus of the invention to be lighter and more mobile and results in a lower power consumption than for comparable pneumatic pump driven systems. The flushing apparatus of the invention can provide a continuous, even flow of flushing fluid when required, and at higher rates of flow than are typically achievable with comparable pneumatically driven pump systems, and is suitable for flushing of the internal oil lubrication chambers of a variety of internal combustion engines, including both gasoline and diesel engines.

The present invention accordingly provides for an engine flushing system for circulating a flushing fluid through an internal combustion engine having an internal oil lubrication system to clean the internal oil lubrication system of the engine, the engine being of the type having an engine block with a first port for receiving a supply of flushing fluid and a second port for returning flushing fluid from the engine to the engine flushing system. The engine flushing system includes a reservoir for flushing fluid, a supply conduit in fluid communication with the first port of the engine for supplying flushing fluid from the reservoir to the first port of the engine, and a return conduit connected in fluid communication with the second port for returning flushing fluid from the second port of the engine to the reservoir. A supply electrical pump is connected in fluid communication with the supply conduit for pumping flushing fluid through the supply conduit from the flushing fluid reservoir to the first port of the engine, and a return electrical pump is connected in fluid communication with the return conduit for pumping flushing fluid through the return conduit from the engine lubrication system to

the reservoir.

A control unit is also provided that is electrically connected with the supply electrical pump and the return electrical pump for controlling operation of the supply electrical pump and the return electrical pump, and in a presently preferred embodiment, the control unit is advantageously connected with each of the supply and return electrical pumps by relays. The control unit preferably comprises a microprocessor controller, and in a presently preferred embodiment, the control unit includes a user interface for receiving instructions from a user for operation of the flushing fluid system, and the interface typically includes a keypad, and a display for displaying a summary of the status of the programming and/or operation of the flushing apparatus.

In one presently preferred embodiment, a coarse filter is provided between the oil pan port of the engine and the return electrical pump. In another presently preferred embodiment, another filter is provided between the return electrical pump and the solution reservoir. In another presently preferred embodiment, a filter is provided in the flushing fluid supply line between the flushing fluid reservoir and the first port for receiving flushing fluid for the engine lubrication system.

In a currently preferred aspect of the flushing system of the invention, the flushing apparatus includes a housing for the flushing fluid reservoir, the supply and return electrical pumps, and for the control unit. The housing also preferably includes reels for supply and return conduits, and electrical connectors between microprocessor and the first and second relays. The housing may also advantageously have a base with wheels, to allow the flushing apparatus to be readily mobile.

These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings, which illustrate by way of example the features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of an engine flushing system, illustrating the flushing apparatus according to the principles of the invention connected to an engine for

flushing of the engine's lubrication system, showing connection of a conduit or hose to the oil pan drain port for returning flushing fluid to the flushing apparatus; Fig. 2 is an enlarged perspective view of a portion of the engine of Fig.

1 illustrating a conduit or hose connected to an oil filter port adapter assembly for delivering the fluid output from the flushing apparatus to the engine; Fig. 3 is a perspective view of a portion of the flushing apparatus control subsystem of the flushing apparatus of Fig. 1; Fig. 4 is a cutaway view of the conduits or hoses of the flushing apparatus and the flushing fluid holding tank of the flushing apparatus for delivering flushing fluid to the engine's lubrication system and for returning flushing fluid to the flushing fluid holding tank; and Fig. 5 is a schematic diagram of the operation of the flushing fluid apparatus of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS While prior engine flushing systems have been used to clean the internal oil lubrication passages of an internal combustion engine with a cleaning solution, it has been found that particulate matter and undissolved, suspended sludge can clog solenoid valves of the engine flushing system circulating the flushing fluid to and from the engine.

Water in the air pressure line from an air compressor to a pneumatic pump can also interfere with operation of the solenoid valve controlling the supply of air pressure to the pump. Such prior pneumatically or hydraulically driven pump systems can also be relatively heavy and bulky, making such systems difficult to move or transport. There is thus a continuing need for an engine flushing system that can address these and other problems.

As is illustrated in the drawings, the invention is accordingly embodied in an improved, clog resistant engine flushing system utilizing relay controlled electric pumps for flushing the oil lubrication systems of internal combustion engines. Referring to Fig. 1, the engine flushing system 10 includes a housing 12 with a base 13 with wheels 14 so that the engine flushing system can be highly mobile, and can be moved within a

service area for servicing of an engine of a vehicle as desired, and allowing the engine flushing system to be easily transported, as necessary. The housing typically conveniently includes one or more boxes 15 or compartments for adapters and tools that may be required during the servicing of an engine of a vehicle. The type of engines that can be serviced by the engine flushing system of the present invention are typically an internal combustion engine 16, having an engine block 17 with internal passages for an internal oil lubrication system, such as a gasoline internal combustion engine, or a diesel internal combustion engine, although other types of engines utilizing alternative fuels, and other types of internal passages of an engine or similar machinery may also be suitable for servicing by the engine flushing system of the invention. Other details of the internal passages of an internal combustion engine and of the types of adapters available for connection of the engine flushing system to the engine are described in U. S. Patents 5,474,098 and 5,791,310, each of which are hereby incorporated by reference herein.

With reference to Figs. 1 and 2, the engine flushing system includes a flushing fluid supply conduit or hose 18 that is connectable to a suitable opening in the engine block for introducing flushing fluid into the internal oil lubrication passages, such as an oil filter port 20, by a suitable oil filter port adapter assembly 22 appropriate for the particular engine. A return conduit or hose 24 is also provided that is connected to the engine oil lubrication passages for receiving"dirty"flushing fluid after it has passed through the internal oil lubrication passages by a suitable oil drain pan port adapter assembly to an oil pan 26, typically at the drain plug port 28.

As is illustrated in Figs. 1,3,4 and 5, the engine flushing system includes a control unit 30 that is preferably a microprocessor controller 32, shown in Figs. 3 and 5, having an appropriate power supply 34 that is connectable to standard line current, and preferably having a user interface 36 allowing for the input of instructions to the control unit from a user for the operation of the flushing fluid system. The control unit is typically located on a lid 37 of the housing, allowing a user or technician to access the electronics and electrical connections of the control system. The control unit can be used to initiate the operation of the engine flushing system, and can include various interfaces and subsystems for controlling the operation and the duration of the flushing treatment.

The user interface typically includes a keypad 38 and a display 40 that typically provides

a display of a summary of the status of the programming and/or operation of the engine flushing system, to allow the user to monitor the programming and operation of the engine flushing system. The control unit is currently preferably connected by an electrical connector 42 to a first relay 44 electrically connected to a first or supply electrical flushing fluid pump 46 connected in fluid communication through the flushing fluid supply conduit with a reservoir or holding tank 48 for the flushing fluid for pumping the flushing fluid through the return conduit from the engine lubrication system from the flushing fluid reservoir. The flushing fluid reservoir can be filled through a fill line 49 having a coupling for connection to a supply tank (not shown). The control unit is also preferably connected by another electrical connector 42 to a second relay 50 electrically connected to a second or return electrical pump 52 connected in fluid communication with the flushing fluid return conduit for pumping flushing fluid through the supply conduit from the flushing fluid reservoir to the engine oil lubrication system.

The supply and return electrical pumps are currently Model 80 electrical diaphragm pumps available from Pump Engineering.

Referring to Fig. 5, the flushing fluid return conduit preferably includes one or more filters for filtering the sludge and other undesirable materials from the flushing fluid, and in a currently preferred embodiment, the flushing fluid return conduit includes a first filter 54 that is a coarse filter for removing larger particles, such as a 2 millimeter or 2.5 millimeter pore size filter for example, connected in fluid communication between the oil pan port of the engine and the first pump. A finer filter can also be provided in the flushing fluid return conduit for removing smaller particles from the flushing fluid, such as a second filter 56 that is currently preferably a 5 micron filter, connected in fluid communication between the first pump and the flushing fluid reservoir. Referring to Fig. 3, the first filter 54 and second filter 56 can have transparent coverings so that the filter media can be viewed, and can be disposed externally on the housing, or behind a viewing window, so that the progress of the filtration of the flushing fluid can be observed. In order to further purify the flushing fluid before it is recirculated through the engine oil lubrication system, the engine flushing system can also provide a third filtration stage for removing even finer particles, such as a third filter 58 that is currently preferably a 3 micron hydraulic filter connected in fluid

communication with the flushing fluid supply line 18 between the flushing fluid reservoir and the engine lubrication system.

Referring to Fig. 4, the engine flushing system housing 12 also typically includes reels 62 for convenient storage and retraction of the supply and return hoses, and houses the flushing fluid reservoir or tank, as well as the supply and return pumps and filters, which can also be disposed within the flushing fluid tank, the control unit and the electrical supply lines connected between the first and second relays and the supply and return pumps for controlling the supply and return pumps.

Referring to Figs. 4 and 5, the control unit can also receive signal input via cable 64 from level sensors 66a, 66b, and 66c disposed in the flushing fluid reservoir for indicating the level of flushing fluid in the flushing fluid reservoir, and the control unit can be programmed to halt the flushing operation if the level of fluid in the reservoir is insufficient.

It should be appreciated that the supply and return electrical pumps of the invention could alternatively be replaced by other suitable types of pumps, such as pumps driven by a small gasoline engine or other suitable power source, or by a single supply side pump where drainage of the"dirty"flushing fluid and return to the flushing fluid reservoir from the engine can be assured, and that the supply pump and the return pump can optionally be supplemented with backup pumps, or the supply pump and return pump may also be replaced by pairs of pumps so that the load on each individual pump is reduced, and so that if one of the pumps should fail, the procedure would not need to be aborted. The control of the operation of the pumps can also be provided through means analogous to the electrical relays of the present invention, such as hydraulic control relays having a control fluid circuit separate from the flushing fluid circuit, that can avoid the problem of condensation in the control line, and that can avoid the problem of clogging of solenoid valves that would otherwise be required to open and close the circulation of sludge carrying flushing fluid.

It will be apparent from the foregoing that while particular forms of the invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.