| 摘要 |
1475349 IC engines - exhaust & gas recirculation NISSAN MOTOR CO Ltd 28 Aug 1974 [31 Aug 1973] 37653/74 Heading F1B The invention relates to an exhaust gas recirculation system for an I.C. engine in which a conduit 18 inter-connects an exhaust conduit 17 and an intake manifold 16 of the engine for recirculation of engine exhaust gas into the intake manifold. A control valve 22 is disposed in the conduit 18 being controlled by a diaphragm unit 26 which is responsive through ducts 70, 72, 74 to suction pressure i.e. vacuum in the intake manifold, there being means operable to delay the transmission of vacuum from the intake manifold to the vacuum chamber 58 upon increase of vacuum. The delaying means is constituted by the ducts 70, 72, the duct 70 being provided with a restriction 76, and the duct 72 being provided with a check-valve 78, the check-valve acting to close the duct 72 when the vacuum in the intake manifold is increased, and acting to open the duct 72 when the vacuum in the intake manifold is reduced at a rate which exceeds a predetermined value. An auxiliary control valve 20 is provided in the recirculation conduit 18 to reduce the flow of engine exhaust gas when the degree of opening of the valve 22 is small. The auxiliary control valve 20 is controlled by a diaphragm unit 24 in response to the vacuum in the Venturi section 14 in the intake conduit 11; the control valve 20 acts to reduce and increase the flow of exhaust gases when the vacuum in the Venturi is low and high respectively. The chambers 54 and 52 opposed to the vacuum chambers 58 and 56 are open to atmosphere. |
