| 摘要 |
<p>PURPOSE:To prevent an engine from damage, by relatively reducing the upper limit value of a supercharging pressure if the engine load exceeds a specified value, when the upper limit value of the supercharging pressure is set high. CONSTITUTION:The pressure chamber 53 of an actuator 50 which drives the waste gate valve 43 of a supercharger 18 is communicated to the down stream side of a compressor 19 through a passage 54, and at the same time, communicated to the upperstream side of the compressor 19 through a supercharging pressure control valve 57, and a throttle 58. An electronic control unit 70 receives various operating status detection signals to control the supercharging pressure control valve 57 on the basis of those signals. In case of the rapid acceleration, etc., the control valve 57 is turned on and opened to elevate the upper limit value of the supercharging pressure, however, when the engine load exceeds the specified value, the control valve 57 is turned of and closed, and the upper limit value of the supercharging pressure is reduced, Thus any engine damage can be prevented.</p> |
