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U.S. Department of Energy
Office of Scientific and Technical Information

Exhaust gas recirculation device

Patent ·
OSTI ID:7253296

An exhaust gas recirculation system is described whereby a part of exhaust gas is recirculated to the downstream of the carburetor throttle valve through an exhaust recirculation passage for removing the nitrogen oxides in exhaust gas discharged from an internal combustion engine. A pressure control valve is provided in the after-flow of the flow control valve which controls the rate of exhaust gas recirculated to the downstream of the throttle valve disposed halfway in said exhaust recirculation passage. The pressure control valve is arranged such that its opening will be reduced when negative pressure in the downstream of the throttle valve is high and that the opening will be enlarged when the negative pressure is low. The amount of exhaust gas taken into the engine is made basically proportional to the air intake so that the recirculation ratio will be maintained substantially constant over a wide range of operation.

Assignee:
Hitachi, Ltd.
Patent Number(s):
US 4027638
OSTI ID:
7253296
Country of Publication:
United States
Language:
English