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

Exhaust gas recirculation system for internal combustion engine

Patent ·
OSTI ID:5944203
An internal combustion engine is provided with an exhaust gas recirculating passage for communicating the intake passage and the exhaust passage thereof. The recirculating passage is provided with a valve for controlling the amount of recirculated exhaust gas. A fundamental air-fuel ratio control value for regulating the air-fuel ratio of the intake gas to a predetermined value is corrected by an operating condition correction value according to the operating condition of the engine. The operating condition correction value is successively changed to an optimal value by comparing the actually obtained air-fuel ratio with a predetermined value. The operating condition correction value for correcting the fundamental air-fuel ratio control value when the exhaust gas recirculation is carried out is changed independently from the same for correcting the fundamental air-fuel ratio correction value when the exhaust gas recirculation is not carried out. The initial values of the former correction value and the latter correction value are compared with each other, while the present values of the former correction value and the latter correction value are compared with each other. The comparison value of the initial values and the comparison value of the present values are compared with each other to detect clogging of the recirculating passage. When clogging is detected, the valve is controlled to compensate for the clogging.
Assignee:
Toyo Kogyo Co., Ltd. (Japan)
Patent Number(s):
US 4471745
OSTI ID:
5944203
Country of Publication:
United States
Language:
English