| 摘要 |
PURPOSE:To enable the optimum air-fuel ratio control even at the transition stage for changing the number of cylinders by detecting the change in the number of operating cylinders by means of the pressure at the lower course of the throttle valve of a suction pipe, and controlling a solenoid valve for carrying out fuel injection in accordance with the detected value in a certain operating time. CONSTITUTION:A circuit 10 for judging the number of operating cylinders detects the load and the number of revolution of an engine 1 from the signals of a pressure sensor 6 and a rotation sensor 7 and, when judged that these are within a set area which represents a predetermined light load condition, outputs a command for a two-cylinder operation to a changeover device 11, stopping the operation of two cylinders out of the four cylinders. Then, when the quantity of suction air is reduced because of the stoppage of the two cylinders, a rise in pressure occurs in a suction pipe 3a, which is detected by means of a pressure sensor 6 and, when the width of the pressure change is reached a certain value DELTAP, judgement is made that a changeover operation is completed and a signal is outputted to a selection circuit 13, which is shifted from an arithmetic circuit 8 to an arithmetic circuit 9. Thereby, the operation of the changeover device 11 and the changeover between the arithmetic circuits 8, 9 for the quantity of fuel feeding can be simultaneously carried out, enabling the optimum air-fuel ratio control, even under the transient condition of changing the number of cylinders. |
