JPS5776255A - Exhaust gas recirculating device - Google Patents

Abstract

PURPOSE:To prevent the misfunction due to the deposit of carbon and as well as contrive to obtain the high precision operation by a method wherein the improvement is introduced around the pressure detecting chamber of a negative pressure regulator at the captioned device equipped with the negative pressure regulator to control a pressure controlling valve insertedly provided in an exhaust gas recirculation (EGR) passage. CONSTITUTION:The exhaust gas recirculating device is equipped with a pressure controlling valve 4 provided within an exhaust gas return passage 3, a pressure chamber 5 and a recirculating valve 6. The pressure controlling valve 4 is controlled to open by being introduced with the negative pressure regulated by the negative pressure regulator 50 into the working pressure chamber 43 of the valve 4. The negative pressure regulator 50 is equipped with the pressure detecting chamber 52 and a suction pressure chamber 53, both of which are separated from each other by a diaphragm 51, a valve body 56 arranged at the suction pressure chamber side of which regulates the opening degree of a valve port 54 or the negative pressure introduced to the working pressure chamber 43. On the other hand, the pressure detecting chamber 52 is rendered to be communicated not only to the pressure chamber 5 through a secondary fixed restrictor 57 but also to a suction port 60 upstream a throttle valve 7 through a primary fixed restrictor 58.