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Method and apparatus for controlling air-fuel ration in internal combustion engine

Patent ·
OSTI ID:6879829
A method is described for controlling the air-fuel ratio in an internal combustion engine having a throttle valve within an intake air passage thereof, and lean mixture sensor means for generating a signal in accordance with a concentration of a specific composition in the exhaust gas. The signal changes in value as an atmospheric pressure around the lean mixture sensor is changed. The method comprises: calculating a reference signal value in accordance with predetermined parameters of the engine; detecting an atmospheric pressure; correcting the calculated reference signal value in accordance with the detected atmospheric pressure; and controlling the feedback of the air-fuel ratio so that the signal is brought close to the corrected reference signal value. An apparatus is described for controlling the air-fuel ratio in an internal combustion engine, comprising: a throttle valve within an intake air passage thereof; lean mixture sensor means for generating a signal in accordance with a concentration of a specific composition in the exhaust gas, the signal changing in value as an atmospheric pressure around the lean mixture sensor means is changed; and means for calculating a reference signal value in accordance with predetermined parameters of the engine.
Assignee:
Toyota Jidosha Kabushiki Kaisha, Toyota
Patent Number(s):
US 4651700
OSTI ID:
6879829
Country of Publication:
United States
Language:
English