| 摘要 |
PROBLEM TO BE SOLVED: To achieve both drastic delay of ignition timing and combustion stability, and to realize rise in exhaust gas temperature when an engine is cold and reduction in HC emission amount. SOLUTION: In a warming up completion state where the temperature of cooling water exceeds 80°C, regular stratified charge combustion operation and homogeneous combustion operation are performed. In a cold engine state where the temperature of the cooling water is below 80°C, to promote activation of a catalytic converter, top dead center injection operation mode is performed. In this state, fuel pressure is corrected so as to become higher than that during the stratified charge combustion operation. In addition, injection start timing ITS becomes before a compression top dead center, injection completion timing ITE becomes after the compression top dead center, and fuel injection is performed astride the compression top dead center. Ignition timing ADV becomes timing delayed at 15°CA to 20°CA from the injection start timing ITS after the compression top dead center. Since the compression top dead center becomes stable due to collapse of a large flow and minute turbulence is generated by energy of spray itself, combustion stability is improved. This enables drastic delay of the ignition timing. COPYRIGHT: (C)2006,JPO&NCIPI |
