| 摘要 |
PURPOSE:To keep the conbustion of an automobile engine good despite the deterioration of a measuring instrument or the change in compression ratio, by controlling the air fuel ratio or ignition time to maintain the ratio of indicated mean effective pressure to the fuel weight at a predetermined value. CONSTITUTION:In an engine with an electronic controller, the ratio of indicated mean effective pressure Pi to fuel weight Gf/N per four cycles is almost constant even if the rotational frequency or shaft torque of the engine changes. The position X of a piston is determined from the angle of a crank to calculate the indicated mean effective pressure Pi in accordance with a formula Pi=(integral Pdx)/Xs where P denotes the pressure of a cylinder corresponding to the position X of the piston and Xs denotes the length of cycle. The value of a variable of DELTAPi/DELTA(Gf/N) is then determined and compared with a reference value previously stored in a control circuit, to control the quantity of fuel (ratio of fuel to air) or the angle of spark advancement by the difference between the compared values. |
