| 摘要 |
PROBLEM TO BE SOLVED: To improve burning condition of homogeneous combustion in a cylinder injection engine. SOLUTION: In homogeneous combustion mode operation of the cylinder injection engine equipped with adjustable valve timing mechanisms 39, 40, it is determined whether or not there is valve overlap in which an intake valve 37 and an exhaust valve 38 are both opened, and when there is the valve overlap, fuel injection timing is set within the valve overlap period. In an operation range provided with the valve overlap, since internal EGR increases due to the valve overlap and cylinder temperature rises, when the fuel injection timing is set within the valve overlap period, atomization of injected fuel can be facilitated. In the operation range provided with no valve overlap, the fuel injection timing is set at or near valve opening timing of the intake valve 37. This can facilitate the atomization of injected fuel by low-pressure boiling or strong air current with reduction of cylinder pressure at the time of opening of the intake valve 37. COPYRIGHT: (C)2005,JPO&NCIPI
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