Internal-combustion engines – Two-cycle – Rear compression
Reexamination Certificate
1999-01-07
2001-02-20
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Two-cycle
Rear compression
C123S06900V
Reexamination Certificate
active
06189495
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to internal combustion engines and more particularly to direct cylinder fuel injection for an internal combustion engine.
BACKGROUND OF THE INVENTION
Internal combustion engines are used in a wide variety of applications to power things such as motor boats, power tools, lawn and garden equipment and a wide range of vehicles. As concern for the environment increases government regulations have been and are being promulgated requiring reduced emissions and improved fuel economy from internal combustion engines. One method used to lower the emissions and fuel consumption of internal combustion engines has been the use of fuel injectors as opposed to carburetors to meter and supply fuel to the engine. Electronic fuel injectors can be precisely timed to deliver metered quantities of fuel to the engine at the appropriate times to reduce emissions and fuel consumption and have therefore been widely used. However, electronic and computer monitored fuel injectors add considerable cost and complexity to the system and are impractical for many small engine systems which do not have a battery or generator to power and control the electronic fuel injection systems.
Another approach to lowering the fuel consumption and emission rates of internal combustion engines is to directly inject the fuel into an engine cylinder as opposed to an intake manifold of the engine which permits better timing of the injection to reduce fuel losses in the exhaust scavenge gases thereby reducing hydrocarbon exhaust emissions and decreasing the fuel consumption of the engine. In some present systems, a fuel injector delivers fuel, usually at a relatively low pressure, to a compression chamber wherein the fuel is mixed with air creating a combustionable mixture which is injected directly into the cylinder of the engine. While these systems have been effective at reducing fuel consumption and emissions from the engine they are relatively expensive due to the fuel injector and the overall complexity of the systems and also increase the size of the engine as the compression chamber is located on top of the cylinder head with one fuel injector mounted adjacent to the compression chamber of each cylinder. This is undesirable for small engines such as those in lawn and garden equipment, boat motors and small motorcycle engines and the like where a compact engine is required. Further, as discussed above fuel injectors add complexity and greatly increase the cost of the engine system.
SUMMARY OF THE INVENTION
For an internal combustion engine having at least one cylinder each with a combustion chamber defined between a cylinder head and a reciprocating piston, a valve selectively communicates a compressor, which has a reciprocating piston driven by a power transmission member, with the engine cylinder to compress a fuel and air mixture within the compressor and inject the mixture directly into the combustion chamber of each cylinder. The mixture is ignited by a spark plug to drive the piston of the engine through its power stroke and rotate the associated crankshaft which is linked through the power transmission member to a crankshaft operably associated with the piston of the compressor to rotate its crankshaft and reciprocate the piston within the compressor and thereby compress and then inject the fuel and air mixture into the engine cylinder.
The valve preferably has a passage therethrough which selectively communicates the compressor with each engine cylinder to inject a precise portion of the mixture into each engine cylinder. For an engine with a single cylinder, the compressor is preferably driven by the transmission member at a 1:1 ratio relative to the main cylinder such that the compressor causes a portion of the mixture to be injected into the main cylinder during substantially the same portion of each cycle of the piston of the main cylinder. Preferably, the injection into the main cylinder is timed so that the fuel mixture loses in the exhaust scavenge gases are minimized to reduce hydrocarbon exhaust emission and also to reduce fuel consumption of the engine.
For an engine with a pair of cylinders, the valve preferably selectively communicates the compressor individually with each of the engine cylinders to inject a precise amount of the fuel and air mixture separately into each of the engine cylinders. In a two-stroke engine application, the compressor is preferably driven by the transmission member at twice the speed of the engine cylinder such that the compressor injects substantially the same amount of the fuel and air mixture into each of the engine cylinders during substantially the same portion of each cycle of each of the engine cylinders.
To reduce the cost and complexity of the system, a carburetor preferably supplies the fuel and air mixture to the compressor and the carburetor and compressor are preferably exteriorly mounted and spaced from the engine providing a compact engine and also reducing heat transfer between the components. When so mounted, a flexible fluid conduit preferably communicates the compressor with a manifold to distribute the fuel and air mixture to the combustion chamber of each cylinder. The manifold preferably has a nozzle adjacent each of its outlets to improve dispersion and atomization of the mixture into the combustion chambers.
Objects, features and advantages of this invention include providing an engine with a fuel and air mixture mechanically injected directly into the combustion chamber of each engine cylinder which provides improved combustion within the combustion chamber, provides a precisely controlled injection event driven by the movement of the piston in the main cylinder, reduces fuel consumption of the engine, reduces exhaust emissions from the engine, allows for simple adjustment of the injection timing, provides improved injection timing to reduce the introduction of fuel into the cylinder exhaust scavenge gases, can be adapted to various existing engine designs with minimal modifications, improves run quality and starting of the engine, can be used with single or multiple cylinder engines, is compact, relatively inexpensive, of relatively simple design and economical manufacture, readily adaptable to a wide range of engine applications, and durable, requires little maintenance and has a long in-service useful life.
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Doerr, co-successor trustee by Barbara E.
Tuckey Charles H.
Tuckey J. D.
Tuckey, co-successor trustee by Jay D.
Huynh Hai
Reising Ethington, Barnes, Kisselle, Learman & McCulloch, P.C.
Walbro Corporation
Yuen Henry C.
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