| 摘要 |
PURPOSE:To prevent the pulsation of pressure in a crank case at the time of low-load operation from spreading into a suction pipe while increasing the detecting accuracy of an air-flow meter by providing a passage-cross section controlling mechanism midway in the passage of a blow-by gas and controlling this mechanism in accordance with the load condition of an engine. CONSTITUTION:In a low-load and low-rotation regions of an engine, an actuator 25 is controlled to reduce the opening of a blow-by gas throttle valve 22, by means of a control circuit 26 into which the output signals of a potentiometer 29 which outputs the signal for opening of a suction throttle valve 2, and a distributor 3 which outputs the signal for the rotation of engine, are inputted. As a result, the pulsation of pressure generated in a crank case 19 is damped down at the throttle valve 22, and prevented from spreading into a suction pipe 1. On the other hand, except at the time of low-load operation, the opening of the blow-by gas throttle valve 22 is increased by means of the control circuit 26, allowing the gas which failed to flow into the suction pipe 1 through a blow-by gas return passage 7, to flow into the suction pipe 1 through the blow-by gas passage 6. |
