| 摘要 |
<p>PURPOSE:To check a rise in suction temperature as well as to lighten a burden on a supercharger and furthermore improve an output variation characteristic to an opening variation in a throttle valve, by controlling pressure at the upstream side of the throttle valve in a load range so properly according to pressure at the downstream side of the throttle valve. CONSTITUTION:In an exhaust passage 3, there is provided with a bypass passage 6, interconnecting the upper and lower sides of a turbine 4a in a supercharger 4, and a waste gate valve 7 to be operated by an actuator 8 is installed in this passage 6. In addition, a passage 10 leading a constant positive pressure from a suction passage 2 and another passage 11 to be interconnected to the atmosphere both are connected to a pressure chamber 8c of the actuator 8, and each of solenoid valves 12 and 13 is installed in each of these passages 10 and 11. And, that whether engine load is more than the specified load approximating to a fully-opened state of a throttle valve 5 or not is examined, and when it is more than the specified load, by way of example, each of these solenoid valves 12 and 13 is controlled by a control unit 14 so as to cause supercharging pressure to become the desired pressure set according to a driving state.</p> |
