| 摘要 |
PROBLEM TO BE SOLVED: To make compatible the large retardation of ignition timing and combustion stability, and to achieve the rise of an exhausted gas temperature at cooling-down, and the reduction of an HC discharge amount. SOLUTION: Normal stratified combustion operation and homogeneous combustion operation are performed in a warming-up finished state. An operation mode is set to a top dead center injection operation mode for promoting the activation of a catalytic converter and reducing HC emission in a cold engine state, fuel injection is performed over a top dead center to set injection start timing ITS before a compression top dead center and injection completion timing ITE after the top dead center. Ignition timing ADV is set after the top dead center. Since a swirl and a tumble are attenuated and minute turbulence is activated and a position change of a piston is small at the compression top dead center, stable combustion is achieved. At a transient time in which a load increases at predetermined change speed or higher, at least part of fuel is injected during an intake stroke as early stage injection I2 as indicated in "b". Consequently, a torque response at a transient time is improved. COPYRIGHT: (C)2007,JPO&INPIT
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