Air-fuel ratio control system

Patent · Tue Mar 24 04:00:00 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
• Country of Publication: United States
• Language: English

Related Subjects

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