| 摘要 |
PROBLEM TO BE SOLVED: To prevent self-ignition at starting an engine even if the engine is supplied with fuel with an octane number easy to be self-ignited. SOLUTION: The octane number of the fuel is calculated according to knock limit ignition timing (or a lag amount of the ignition timing) set by knock control during engine operation. When the octane number of the fuel is in a predetermined area of self-ignition generation (an area where the self-ignition due to compression of fuel/air mixture might occur at starting the engine), the timing of closing an intake valve 35 at starting the engine is delayed more than usual by a variable valve timing device 36 so as to execute starting time real compression ratio lowering control for making a real compression ratio of the fuel/air mixture at starting the engine lower than usual, thus lowering the real compression ratio of the fuel/air mixture at starting the engine to a degree that self-ignition does not occur. The generation of the self-ignition caused by the compression of the fuel/air mixture at starting the engine is prevented thereby, even if the engine 11 is supplied with the fuel easy to be self-ignited. COPYRIGHT: (C)2009,JPO&INPIT
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