| 摘要 |
PURPOSE:To control an EGR quantity and a supercharge pressure accurately by leading a supply air pressure and a pressure in the upstream of EGR regulation valve to a waste gate valve while switching in accordance with the vehicle speed such that when the upstream pressure is led in, the supply air pressure is led to EFR regulation valve so as to close the EGR regulation valve. CONSTITUTION:A waster gate valve 66 arranged in a bypath 62 for a turbine 16 of a supercharger 4 is driven by an actuator 68 to which the pressure supply is switched by a changeover valve 80 between a first pressure conduit 82 for leading in the pressure from an air supply path and a second pressure conduit 84 for leading in the upstream pressure of a regulation valve 22 arranged in an EGR path 20. When the vehicle speed is higher than a setting level, the changeover valve 80 switches to the second pressure conduit 82 side by means of a control section 52 which receives signals from a rotation sensor 54, a throttle sensor 56, a supply air pressure sensor 58 in the downstream of a throttle valve, etc. Under low load or when the changeover valve 80 is switched to the second pressure conduit 82 side, a changeover valve 50 for regulating EGR leads in the supply air pressure in the upstream of the throttle valve through a conduit 46 so as to close the EGR regulation valve 22. |
