| 摘要 |
PROBLEM TO BE SOLVED: To provide a clean internal combustion engine allowing expansion of an operation range of compression self-ignition combustion, improving fuel consumption and emission, with high thermal efficiency. SOLUTION: Using a variable valve timing mechanism 19 capable of being set to minus overlap at the self-ignition combustion time and a swirl control valve 20 capable of blocking one intake port 11, an inner EGR gas layer-a high temperature gas layer-and a new gas layer-a low temperature gas layer-are laminated in a combustion chamber, and fuels are injected to the EGR gas layer and the new gas layer, respectively. The fuel injection to the new gas layer is performed prior to that to the EGR gas layer, and the fuel injection to the EGR gas layer is varied according to an operation condition near a compression upper dead point. When the fuel is injected to the EGR gas layer that is compressed to the proximity of the compression upper dead point and heated up to about 1000 K, high temperature oxidation reaction is instantly started to cause the self-ignition with little ignition delay time. Pressure increase by the combustion of the EGR gas layer transmits to cause self-ignition of the new gas layer. |
