초록 ▼

An EGR control valve is closably disposed in an EGR passageway connecting an intake passageway and an exhaust gas passageway which leads to an internal combustion engine. The EGR control valve is operated to control recirculated exhaust gas flow by varying the exhaust gas pressure in a chamber betwe

An EGR control valve is closably disposed in an EGR passageway connecting an intake passageway and an exhaust gas passageway which leads to an internal combustion engine. The EGR control valve is operated to control recirculated exhaust gas flow by varying the exhaust gas pressure in a chamber between a restriction disposed in the EGR passageway and the EGR valve, in accordance with variations in a venturi vacuum in the intake passageway to prevent the recirculated exhaust gas flow from being affected by the exhaust gas pressure in the EGR passageway upstream of the chamber. Furthermore, the EGR control valve is arranged to be controlled so that the amount of the recirculated exhaust gas flow is reduced during high engine speed and low load engine operation.

대표청구항 ▼

An exhaust gas recirculation (EGR) control system in combination with an internal combustion engine including means defining an intake passageway providing communication between the atmosphere and the combustion chamber of the engine, means defining a venturi formed in the intake passageway, a throt

An exhaust gas recirculation (EGR) control system in combination with an internal combustion engine including means defining an intake passageway providing communication between the atmosphere and the combustion chamber of the engine, means defining a venturi formed in the intake passageway, a throttle valve rotatably disposed in the intake passageway downstream of the venturi, and means defining an exhaust gas passageway providing communication between the combustion chamber of the engine and the atmosphere, said EGR control system comprising: means defining an EGR passageway providing communication between the exhaust gas passageway and the intake passageway for recirculating thereinto exhaust gas emitted from the engine; an EGR control valve disposed in said EGR passageway to separate said EGR passageway into two parts, said EGR control valve being operable in opposite directions to increase and reduce the pressure of engine exhaust gas in the part of said EGR passageway upstream of said EGR control valve for controlling the flow of recirculated engine exhaust gas; means for operating said EGR control valve in opposite directions to increase and reduce the exhaust gas pressure in the part of said EGR passageway upstream of said EGR control valve in accordance with a decrease and an increase in said exhaust gas pressure and in accordance with a decrease and an increase in a venturi vacuum in said venturi, respectively; and means for decreasing the degree of said venturi vacuum applied to said operating means during high speed and low load engine operation.