Exhaust gas recirculation

Patent · Tue Mar 26 04:00:00 EDT 1974

OSTI ID:7361776

Bolton, R A

An exhaust gas recirculation method for reducing nitrogen oxide emissions from internal combustion engines is described which utilizes the exhaust back pressure to recirculate exhaust gases at a rate proportional to air flow and in a manner by which recirculation of the exhaust gases through the carburetor is avoided. An exhaust gas recirculation passage is provided which extends from the engine exhaust passage to the engine air reduction passage at a point downstream of the engine throttle. An orifice is provided in the recirculation passage, and a valve disposed downstream of the orifice is operated to create a zone of substantially constant pressure the passage irrespective of the wide variations in exhaust back pressure and induction passage vacuum. The pressure in the zone may be maintained either above or below atmospheric pressure, and the rate of flow of exhaust gases into and through the zone will be proportional to the rate of induction air flow.

• Assignee: General Motors Corp.
• Patent Number(s): US 3799131
• OSTI ID: 7361776
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330701* -- Emission Control-- Nitrogen Oxides
CHALCOGENIDES
CONTROL
CONTROL EQUIPMENT
DESIGN
DUCTS
ENGINES
EQUIPMENT
EXHAUST RECIRCULATION SYSTEMS
EXHAUST SYSTEMS
FLOW REGULATORS
INTERNAL COMBUSTION ENGINES
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL EQUIPMENT
PRESSURE CONTROL
VALVES