Air-fuel ratio control system

Patent · Tue Mar 24 00:00:00 EST 1987

OSTI ID:6652608

Ohtacki, K; Hara, K

This patent describes an air-fuel ratio control system for an internal combustion engine comprising an induction passage; means for supplying air-fuel mixture to the engine; an electromagnetic valve for correcting the air-fuel ratio of the air-fuel mixture supplied by the supply means; an O/sub 2/ sensor for detecting oxygen concentration in exhaust gases of the engine; and a feedback control circuit including the following, comparator means for comparing the output of the O/sub 2/ sensor with a reference value for producing a first output signal, PI circuit means responsive to the first output signal of the comparator means for producing a PI value. The PI circuit means has a constant. A pulse generating circuit means is responsive to the PI value for generating pulses having a duty ratio which is dependent on the PI value. The pulses are for driving the electromagnetic valve to correct the air-fuel ratio. The feedback control circuit is operatively connected to the O/sub 2/ sensor and to the electromagnetic valve performing closed loop air-fuel ratio feedback control. The improvement described here comprises: engine operating condition detecting means responsive to pressure in the induction passage for producing a second output signal dependent on the pressure; and engine acceleration detecting means responsive to the second output signal for producing a first acceleration signal when fluctuation of the second output signal is within a predetermined range and continues for a predetermined time, and for producing a second acceleration signal when the fluctuation is out of the predetermined range.

• Assignee: Fugi Jukogyo Kabushiki Kaisha, Tokyo
• Patent Number(s): US 4651695
• OSTI ID: 6652608
• Resource Relation: Patent File Date: Filed date 15 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
INTERNAL COMBUSTION ENGINES
CONTROL SYSTEMS
FUEL-AIR RATIO
COMPARATOR CIRCUITS
ELECTROMAGNETS
EXHAUST GASES
FEEDBACK
INTAKE STRUCTURES
MIXTURES
OXYGEN METERS
SIGNALS
VALVES
VELOCITY
CONTROL EQUIPMENT
DISPERSIONS
ELECTRICAL EQUIPMENT
ELECTRONIC CIRCUITS
ENGINES
EQUIPMENT
FLOW REGULATORS
FLUIDS
GASEOUS WASTES
GASES
HEAT ENGINES
MAGNETS
MEASURING INSTRUMENTS
MECHANICAL STRUCTURES
METERS
WASTES
330100* - Internal Combustion Engines