Abstract: A system and method are disclosed for fabricating and running an engine in two modes. The first mode is an efficiency mode having a high compression ratio and efficiency for low to medium loads. The second mode is a power mode having high power density for higher loads. The system may use a lean mixture in the efficiency mode, which mixture is made richer for more power in the power mode. The system may also use ignition timing to allow the efficiency mode and the high power mode to be at the same mixture.

Abstract: An internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.

Abstract: A sleeve valve assembly. The assembly includes a valve seat, a sleeve valve and an oil path-defining piece. The sleeve valve includes a distal end with a cavity. The distal end contacts the valve seat when the sleeve valve is located in a closed position. The oil path-defining piece includes an inlet port, an outlet port and a plurality of cooling passages. The flange of the sleeve valve is slidably in contact with the oil path-defining piece such that cooling fluid travelling into the inlet port and through the cooling passages enters into the cavity before exiting out the exit port.

Abstract: An internal combustion engine. The engine includes at least one cylinder having a bore diameter, a piston for traveling within each cylinder between a first position and a second position, wherein the distance between the first position and the second position defines a stroke length, and thermal barriers on the surfaces of the combustion chamber near top dead center. In one embodiment, the engine utilizes asymmetric effective compression and expansion strokes. To maximize efficiency of the engine, a ratio of the bore diameter to stroke length of the internal combustion engine comprises a range between 0.5 to 1.0.

Abstract: An internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.

Abstract: An internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.

Abstract: An internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.