Air-fuel ratio control system
In an air-fuel ratio control system for a carburetor of an internal combustion engine having an intake passage, and an exhaust passage from the engine, this patent describes the control system comprising an O/sub 2/ sensor for detecting concentration of a constituent of exhaust gases passing through the exhaust passage. There is an on-off electromagnetic valve for correcting the air-fuel ratio of air-fuel mixture supplied by the carburetor, an electronic control circuit comprising a comparator for comparing an output signal of the O/sub 2/- sensor with a reference value and outputting a correcting signal, an integration circuit operatively connected to the comparator and driving a circuit for producing driving pulses for driving the electromagnetic valve . The improvement comprises: detector means for detecting speed of the internal combustion engine for producing an air operation signal constituting an engine speed signal; current control circuit means responsive to the engine speed signal for producing an output current dependent on the speed signal; and delay circuit means responsive to the output current for delaying the correcting signal operatively received by the integration circuit by a delay time such that the delay time increases with decreasing engine speed, so as to keep the air-fuel ratio at a rich value dependent on the engine speed.
- Assignee:
- Fuji Jukogyo Kabushiki Kaisha, Tokyo
- Patent Number(s):
- US 4697564
- OSTI ID:
- 5776918
- Country of Publication:
- United States
- Language:
- English
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Air-fuel ratio control system
Air-fuel ratio control system