JPS566055A - Exhaust gas recirculator - Google Patents

Abstract

PURPOSE: To reduce effectively NO_x which is generated in a large quantity on accelerating by providing, in the exhaust gas recirculating passage of an internal combustion engine, the first control valve which opens or closes the passage corresponding to exhaust gas pressure and the second control valve which opens the passage wider on accelerating.

CONSTITUTION: The suction and exhaust gas systems of an engine 1 are connected by an exhaust gas recirculating passage 4. In the passage 4, the first control valve 6 is provided and the degree of negative pressure introduced to its engative pressure chamber 62 is adjusted by a negative pressure adjusting valve 30 which opens or closes corresponding to the exhaust gas pressure in a constant pressure chamber 5. Also in the passage 4, the second control valve 7 is provided, and to its negative pressure chamber 72, the negative pressure of the suction system 3 is introduced via an atmosphertic pressure introducing valve 9. The introducing valve 9 is adjusted of its atmosphertic air introducing quantity by the suction negative pressure on the upstream side of a throttle valve 21, and utilizing the decrease of the degree of negative pressure when the engine is accelerated, reduces the degree of negative pressure chamber 72 and increases the opening of a valve 74.

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