| 摘要 |
An internal combustion engine having a direct cylinder injection and including a variable valve timing mechanism for at least changing the time of closing of the intake valve. The fuel injection timing and intake valve closing timing are controlled so that under low and mid-range engine speeds, but high loads, the intake valve is closed before the piston reaches bottom dead center position on its intake stroke so as to reduce the effective compression ratio. Fuel injection timing is begun before the piston has reached its bottom dead center position during the intake stroke under high-speed, high-load conditions and is not initiated until after the piston has reached its bottom dead center position and begun its compression stroke under other engine running conditions. The engine is provided with an injector location and piston with a bowl in its head that improves fuel stratification under at least some running conditions so as to permit lean burn operation. The intake valves are offset to one side of a plane containing the axis of the cylinder bore, and the fuel injector is disposed between a pair of intake ports and below them so as to direct its injection axis toward the exhaust side and toward the recess in the head of the piston.
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