System for and method of controlling air-fuel ratio in internal combustion engine
AssigneeUnisia Jecs Corporation
InventorJunichi Furuya
Life of this patent
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Abstract
In an air-fuel ratio control system for an internal combustion engine, a proportional part for determining a feedback correction factor is corrected by a value proportional to an intake air flow corresponding value, whereas an integral part for determining the feedback correction factor is corrected by a value proportional to a square of the intake air flow corresponding value.
Claims4
A system for controlling an air-fuel ratio of air-fuel mixture to be supplied to an internal combustion engine, the system comprising:
- an air-fuel ratio sensor means for providing an output value variable in response to a concentration ratio of a constituent in exhaust, said concentration ratio being variable according to the air-fuel ratio;
- an air-fuel ratio feedback control means for comparing said output value of said air-fuel ratio sensor means with a reference value corresponding to a target air-fuel ratio and controlling the air-fuel ratio to be close to said target air-fuel ratio by using a feedback correction factor;
- a proportional part setting means for setting a proportional part for determining said feedback correction factor, said proportional part being corrected by a value proportional to an intake air flow corresponding value;
- and
- an integral part setting means for setting an integral part for determining said feedback correction factor, said integral part being corrected by a value proportional to a square of said intake air flow corresponding value.
A method of controlling an air-fuel ratio of air-fuel mixture to be supplied to an internal combustion engine, the method comprising the steps of:
- providing an output value variable in response to a concentration ratio of a constituent in exhaust, said concentration ratio being variable according to the air-fuel ratio;
- comparing said output value of said air-fuel ratio sensor means with a reference value corresponding to a target air-fuel ratio and controlling the air-fuel ratio to be close to said target air-fuel ratio by using a feedback correction factor;
- setting a proportional part for determining said feedback correction factor, said proportional part being corrected by a value proportional to an intake air flow corresponding value;
- and
- setting an integral part for determining said feedback correction factor, said integral part being corrected by a value proportional to a square of said intake air flow corresponding value.
Dependencies are inferred from the claim text.