| 摘要 |
PURPOSE:To aim at reduction in a rate of fuel consumption at the time of partial load in a multistage turbosupercharged engine, by opening the valve set up in a bypass passage of a small discharge turbine at the high pressure side selectively at the time of the partial load. CONSTITUTION:A multistage turbosupercharged engine regulates a gas flow rate of a small discharge turbine 8 by a flow control valve 11, while a gas flow rate of a large discharge turbine 9 is regulated by a waste gate valve 13. Supercharging pressure PB is fed to each of actuators 21 and 22 for these turbines, and controlled by control pressure regulating valves 25 and 26 which output according to the supercharging pressure PB and an engine speed NE. When attaching importance to accelerability in a car, a manual economy switch 32 is turned off in advance. When aiming at the retrenchment of fuel consump tion at driving on an urban district, if the economy switch 32 is turned on, a gate valve 31 is opened whereby negative pressure in a suction manifold 23A at the time of partial load in an engine 1 is led into a spring chamber 21B of the actuator 21, thus the flow control valve 11 is opened. |
