JPS5728856A - Exhaust gas recirculation device - Google Patents

Abstract

PURPOSE: To stop instantaneousely the recirculation of exhaust gas at the reduction of engine speed, by providing a negative pressure control valve adapted to lead atmosphere into a negative pressure chamber of an exhaust gas recirculation device only when the speed of the engine is reduced.

CONSTITUTION: Intake and exhaust manifolds 3, 4 of an engine 1 are intercommunicated through a recirculation conduit 5 having a control valve 6 for exhaust gas recirculation so as to recirculate exhaust gas. The negative pressure chamber 62 of the control valve 6 opens to an intake conduit positioned directly above in way of a negative pressure conduit 13 when a throttle velve 22 is closed perfectly. The conduit 13 is also communicated to a diaphragm chamber 82 of a negative pressure control valve 8 through a negative pressure delay valve 10, and the control valve is thus opened by a high negative pressure occurred when the speed of the engine is reduced. Furthermore, the conduit 13 can be communicated to an intake conduit in the upper stream of the valve 22 in way of a conduit 14 when the control valve is released. The exhaust gas control valve is thereby closed in such that atmosphere is led momentarily into the negative pressure chamber 72 by releasing the negative pressure control valve 8 when the speed of the engine is reduced.

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