A vehicle engine includes a cylinder block, a cylinder head installed at an upper portion of the cylinder block and forming a combustion chamber therein, a piston installed at the cylinder block and reciprocating in the cylinder block so that the volume of the combustion chamber is compressed or expanded, an injector installed at the cylinder head for injecting fuel into the combustion chamber, a spark plug installed at the cylinder head for igniting the fuel injected from the injector, and a voltage generating member installed inside the piston so that a voltage is generated by a pressure generated during a compression stroke of the piston.

A carburetor for a two-stroke internal combustion engine whereby airtightness is maintained and intake of uncombusted fuel into an air path is prevented. The carburetor includes a circular cylindrical valve hole and a rotary valve fitted into the valve hole such that it can rotate and is disposed perpendicularly across a fuel intake path and an air intake path which are formed substantially parallel with respect to each other, and a fuel supply-side bore which controls the flow rate along the fuel intake path and the air supply-side bore which controls the air capacity along the air path pass through part of the cylindrical portion perpendicularly to the axial direction of the rotary valve, and annular recesses formed in part of a circumferential wall of an outer circumference of the rotary valve so as not to correspond to at least the fuel supply-side bore and the air supply-side bore.

A carburetor for a two-stroke internal combustion engine whereby airtightness is maintained and intake of uncombusted fuel into an air path is prevented. The carburetor includes a circular cylindrical valve hole and a rotary valve fitted into the valve hole such that it can rotate and is disposed perpendicularly across a fuel intake path and an air intake path which are formed substantially parallel with respect to each other, and a fuel supply-side bore which controls the flow rate along the fuel intake path and the air supply-side bore which controls the air capacity along the air path pass through part of the cylindrical portion perpendicularly to the axial direction of the rotary valve, and annular recesses formed in part of a circumferential wall of an outer circumference of the rotary valve so as not to correspond to at least the fuel supply-side bore and the air supply-side bore.

An engine includes a combustion chamber, a fuel injector, a spark plug, and a piston. The combustion chamber receives air from an intake valve, which receives air from an external environment of the engine. The fuel injector includes a fuel channel, a fuel port, an air port, a needle valve, and a premixing tube. The fuel channel receives fuel from a fuel supply. The needle valve initially covers the fuel port, and actuates to fluidly connect the fuel port to the fuel channel such that the fuel port receives the fuel. The air port draws air into the fuel injector, and the premixing tube mixes the air and fuel to create a mixture. The mixture is fed into the combustion chamber along a central axis of the premixing tube such that the mixture intersects the electrode of the spark plug, which ignites the mixture to actuate the piston.

A fuel injection valve is provided for a ceiling portion of a cylinder head. A tip of an ignition electrode is arranged in the vicinity of an injection tip of the fuel injection valve. A recess is provided for the ceiling portion. A center of a cavity is shifted with respect to a bore center of the cylinder. In a vertical cross-section of the inside of a combustion chamber taken along a plane passing through the injection tip of the fuel injection valve and the tip of the ignition electrode, a distance from the injection tip to a wall surface of the cavity at a side at which the ignition electrode is provided is longer than a distance from the injection tip to a wall surface of the cavity at an opposite side.

In certain embodiments, a two-stage precombustion chamber may be used to reduce engine NOx levels, with fueled precombustion chambers, while maintaining comparable engine power output and thermal efficiency. One or more fuel admission points may be located in either the first prechamber stage or the second prechamber stage. A more efficient overall combustion characterized by low levels of NOx formation may be achieved by a two-stage precombustion chamber system while generating very high energy flame jets emerging from the second prechamber stage into the main combustion chamber. A first prechamber stage may be substantially smaller than a second prechamber stage. The volumes and aspect ratios of the two prechamber stages, along with the location of the electrodes within the first stage prechamber, the holes patterns, angles and the separate fueling, may be selected to create a distribution of fuel concentration that is substantially higher in the first stage prechamber compared to the second prechamber stage.

Fuel management system for efficient operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder of the engine. A fuel management microprocessor system controls injection of the anti-knock agent so as to control knock and minimize that amount of the anti-knock agent that is used in a drive cycle. It is preferred that the anti-knock agent is ethanol. The use of ethanol can be further minimized by injection in a non-uniform manner within a cylinder. The ethanol injection suppresses knock so that higher compression ratio and/or engine downsizing from increased turbocharging or supercharging can be used to increase the efficiency or the engine.

Fuel management system for efficient operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder of the engine. A fuel management microprocessor system controls injection of the anti-knock agent so as to control knock and minimize that amount of the anti-knock agent that is used in a drive cycle. It is preferred that the anti-knock agent is ethanol. The use of ethanol can be further minimized by injection in a non-uniform manner within a cylinder. The ethanol injection suppresses knock so that higher compression ratio and/or engine downsizing from increased turbocharging or supercharging can be used to increase the efficiency or the engine.

A control device for an internal combustion engine is programmed, during a catalyst warm-up control, to perform first fuel injection by an injector in an intake stroke, control an ignition device so as to generate a discharge spark in a predetermined period in an expansion stroke, and perform second fuel injection, at a timing retarded from a compression top dead center, such that its injection period overlaps with at least a part of the predetermined period and an end timing of the injection period is advanced from an end timing of the predetermined period. Further, the control device is programmed, during the catalyst warm-up control, to control an actual tumble ratio depending on a result of determination using a first index value representing a speed of initial combustion accompanying an ignition by the ignition device and a second index value representing a speed of main combustion accompanying the ignition.

To improve the effect of preventing contamination of an element in an air cleaner. An air cleaner includes a first inlet (60) through which air is fed to an intake system air passage and a second inlet (62) through which air is fed to an intake system air-fuel mixture passage. An extended passage (72) leads to the second inlet (62), for example. A passage forming member (70, 204) forming the extended passage (72) is shaped to surround a periphery of the first inlet (60). The passage forming member (70, 204) forms a blown-back fuel diffusion preventing region (74) leading to the first inlet (60).