Exhaust gas recirculation system for an internal combustion engine
The disclosed engine exhaust gas recirculation (EGR) system has an EGR passage for recirculating exhaust gases from an exhaust system of an engine back into an intake system thereof downstream of a throttle valve. The EGR passage has a restriction orifice therein and an EGR control valve responsive to a vacuum signal to control the recirculation of exhaust gases through the EGR passage. A pressure comparator and modulator is pneumatically connected to the EGR passage upstream and downstream of the restriction orifice, to the carburetor venturi, to the intake manifold and to the EGR control valve and operative to compare the venturi vacuum with the exhaust gas pressure difference across the restriction orifice thereby to modulate the intake manifold vacuum to be fed to the EGR control valve so that the latter is controlled by the thus modulated vacuum to keep the exhaust gas pressure difference proportional to the venturi vacuum whereby the volumetric quantity of recirculated exhaust gases is made proportional to the volumetric quantity of engine intake air.
- Assignee:
- Nippon Soken, Inc.
- Patent Number(s):
- US 4148286
- OSTI ID:
- 6299486
- Resource Relation:
- Patent Priority Date: Priority date 1 Oct 1976, Japan
- Country of Publication:
- United States
- Language:
- English
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