| 摘要 |
PURPOSE:To suppress torque changes of an engine by splitting imdividual cylinders of the engine into high compression ratio cylinders and low compression ratio cylinders and by controlling so as to make the air-fuel ratio of the high compression ratio cylinders small based on the output from an O2 sensor provided on the exhaust side of the low compression ratio cylinders. CONSTITUTION:When a four-cylinder engine is applied, the No.1 cylinder is set at a low compression ratio and the No.2 through No.4 cylinders are set at a high compression ratio, for instance. An injection valve with flow characteristics of the alpha times (alpha>1) injection quantity per equal valve opening time that of other injection valves (b)-(d) is used for the injection valve (a) corresponding to the No.1 cylinder. The injection quantity is controlled by feeding back so that the air-fuel ratio of the No.1 cylinder is kept at the theoretical air-fuel ratio by a control circuit 29 in accordance with the output from an O2 sensor 6 fitted to only the exhaust passage 27 on the No.1 cylinder side. At the same time, the injection quantity of the No.2 through No.4 cylinders is controlled by the above feedback signal or the other signal proportional to it to obtain a desired thin air-fuel ratio. |
