GB1450930A - Control system for exhaust gas recirculating valve - Google Patents

Abstract

1450930 Treating IC engine charge RANCO Inc 28 Dec 1973 [2 Jan 1973] 59982/73 Heading F1B [Also in Division G3] An exhaust gas recirculation system comprises an exhaust gas recirculation valve 14 controlling the flow of exhaust gas from the exhaust manifold 15 to the inlet manifold 13 of an I.C. engine, a fluid-pressure regulator 26 controlling the pressure applied to the valve 14 in dependence upon the rate of flow of air through venturi 12, and a secondary vacuum control valve 34 which overrides the regulator 26 to close the valve 14 whenever the throttle plate 11 of the carburetter moves to a closed or idle position. When the throttle plate 11 is fully open a low vacuum prevails at port 63 downstream of the venturi 12 which, when applied to a chamber 52 of the control valve 34 causes valve-member 56 to shut off the vacuum derived from the inlet manifold 13 and admit atmospheric air from vent 60 to the port 55 and thence chamber 20 of the valve 14 so that the valve-member 24 closes. When the throttle plate 11 is positioned in its mid range, the port 63, being downstream of the plate communicates an increased vacuum to the chamber 52 which in turn opens the valve 14. When the throttle plate 11 moves to its idle or closed position the port 63 becomes located upstream of the plate and once again a low vacuum prevails which, when applied to chamber 52 causes the valve 14 to close. A check valve or reservoir may be placed in conduit 27 so that a sudden drop in vacuum in the manifold 13 will not necessarily cause a loss in vacuum in chamber 20.