Air-fuel ratio control system
An air-fuel ratio control system is disclosed for an internal combustion engine having an intake passage, an exhaust passage, an air-fuel mixture supply, on-off type electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply, a dither signal generating circuit for producing a periodical dither signal having a constant wave pattern, a shift control circuit for shifting the level of the center of the dither signal, a driving circuit for producing a driving output according to the dither signal, and an O/sub 2/ sensor for detecting the concentration of oxygen in exhaust gases passing through the exhaust passage. The system is provided with a device for detecting a transient state of the engine operation, and a control circuit including an integrating circuit connected to the O/sub 2/ sensor and a square wave generating circuit for generating square pulses according to the integration output of the integrating circuit for driving the electromagnetic valve. A switching circuit is provided for connecting the O/sub 2/ sensor to the control circuit and disconnecting the shift control circuit from the O/sub 2/ sensor in dependency on the output signal of the device for detecting the transient state. Thus, in the transient state, the air-fuel ratio is controlled by the integration output signal of the control circuit, whereby the air-fuel ratio may be quickly controlled to the stoichiometric air-fuel ratio.
- Assignee:
- Fuji Jukogyo Kabushiki Kaisha (Japan); Nissan Motor Co., Ltd. (Japan)
- Patent Number(s):
- US 4402293
- OSTI ID:
- 5440674
- Country of Publication:
- United States
- Language:
- English
Similar Records
Air-fuel ratio control system
Air-fuel ratio control system
Related Subjects
330100* -- Internal Combustion Engines
CONTROL EQUIPMENT
CONTROL SYSTEMS
DETECTION
ELECTRONIC CIRCUITS
ELEMENTS
ENGINES
EQUIPMENT
EXHAUST GASES
FLOW REGULATORS
FLUIDS
FUEL FEEDING SYSTEMS
FUEL SYSTEMS
FUEL-AIR RATIO
GASEOUS WASTES
GASES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
NONMETALS
OXYGEN
SIGNALS
VALVES
WASTES