PURPOSE: To prevent the reduction in output due to the deficiency of intake air quantity, by providing a timing valve which opens or closes the intake air passage for each cylinder, and further by operating so as to close the timing valve for the cylinder in which intake air flows for a prescribed time at the initial stage of inflow.
CONSTITUTION: Into a control circuit 29, detected signals such as those of throttle opening, engine speed, turning angle of an eccentric shaft, or the like are input, and when it is in a pumping-loss control region, a control valve 20 is brought into a NON- advance D condition via a advancer 23, and a negative pressure is introduced into an actuator 28 by changing over a threeway solenoid 31 to open a communicating valve 27, so that the pumping loss control can be carried out by communicating neighbouring cylinders. In other words, a spitting preventive valve 21 is closed to prevent the spitting to be caused in the cylinder on the side to which intake air flows through a communicating passage 26. In this case, although the opening period of the control valve 20 becomes short, since the required intake air quantity is relatively less in a partial load region, the required air quantity can be sufficiently maintained. Further, when it is not in a pumping-loss control region, the communicating pipe 27 is closed via the three-way solenoid 31 and the actuator 28.
HIDEHIRA YOSHIHIRO
OKIMOTO HARUO
TAJIMA SEIJI
