| 摘要 |
PURPOSE:To hold engine characteristics in an excellent state, by a method wherein an air-fuel ratio and an ignition timing are controlled so that a ratio between a pressure average effective pressure in a cylinder and a fuel weight per 4 cycles, detected from a rotation speed and an injection period, is held at a given value. CONSTITUTION:During running of an engine, an incylinder pressure signal, detected by a pressure pickup 11 mounted in a state to be attached to an ignition plug, is inputted to a pressure signal processing circuit 12. An average effective pressure is calculated therein to generate an electric signal responding to an average effective pressure, and the signal is inputted to a microcomputer 8 for controlling an engine and an ignition control circuit 10. A ratio between the average effective pressure and a fuel weight per 4 cycles (suction, compression, explosion, and exhaust), detected from an engine rotation speed obtained from an output from a crank angle sensor 17 and a separately computed injection period, produces one variable, and a fuel injection amount from an injection valve 4, i.e. an air-fuel ratio, is controlled and the ignition timing of the ignition plug is controlled so that the ratio is held at a given value.
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