ENGINE EQUIPED WITH SUPERCHARGER

摘要

PURPOSE:To restrain the occurance of torque shock by arranging a mechanical supercharger and a throttle valve in series and by providing a return passage to the supercharger whereby leaving the return passage open for a specified period of time when the supercharger starts operating. CONSTITUTION:A throttle valve 3 and a root pump 2 in order from the upstream side are provided in series in a suction passage 11 wherein the root pump 2 is driven by an engine main body 1 by way of an electromagnetic clutch and the like. And a bypass passage 13 bypassing the root pump 2 and a return passage 14 are provided in parallel each other in the suction passage 11 wherein a bypass valve 5 and a return valve 9 are provided to each of the passages 13 and 14 respectively. And a bypass passage 17 bypassing the throttle valve 3 is provided wherein a closing valve 7 is provided to the passage 17. And when the root pump 2 starts operating, both of the closing valve 7 and the return valve 9 are kept open for a specified period of time thereby making the difference in pressure small between the upstream and downstream of the throttle valve 3 and between the upstream and downstream of the root pump 2.