| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve consumption by optimizing the ignition timing of a pre-mixed air-fuel mixture in spite of a large change in EGR rate and variation of the temperature condition of circulating exhaust emission and a combustion chamber 4 in a direct-injection type diesel engine 1 in which when the engine 1 is in a pre-mix combustion region (H) on low load side, fuel is relatively early main-injected by an injector 5 facing to the combustion chamber 4, and the EGR rate is heightened to achieve pre-mix compression ignition combustion. <P>SOLUTION: Fuel is sub-injected near BTDC17° in CA, for example, in response to cool flame reaction in a pre-mixed air-fuel formed by main injection fuel, and the temperature of the pre-mixed air-fuel is lowered by the vaporized latent heat of the fuel to delay the ignition timing near TDC. According to the change in estimated value of EGR rate and crank angular speed, the sub-injection amount is controlled to optimize the ignition timing of the pre-mixed air-fuel, whereby heat generation pattern having high cycle efficiency can be realized to improve fuel consumption. <P>COPYRIGHT: (C)2004,JPO |
