| 摘要 |
PROBLEM TO BE SOLVED: To improve a specific power of an internal combustion engine, eliminating restrictions in knocking. SOLUTION: The internal combustion engine includes a turbocharger and a variable compression ratio mechanism for varying a mechanical compression ratio. In a first operating range where a torque is increased by supercharging but a load is relatively small, a spark ignited combustion mode (SI) is set, where combustion approximated to a constant volume combustion cycle by a spark ignition of a premixed air fuel mixture is achieved. In a second operating range where the load is relatively large, a constant pressure combustion mode is set, where combustion approximated to a constant pressure combustion cycle by a control of a heat generating ratio is achieved. In the spark ignited combustion mode, a target compression ratio is set lower as the load increases. On the other hand, in the constant pressure combustion mode, the target compression ratio is set higher in order to compensate a time loss due to lengthening of the combustion. Thereby, a greater amount of fuel and fresh air can be supplied into a cylinder to improve the specific power. COPYRIGHT: (C)2010,JPO&INPIT |
