Air-fuel ratio control system for engine
AssigneeMazda Motor Corporation
InventorsFutoshi Nishioka, Tetsushi Hosokai
Life of this patent
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Abstract
An air-fuel ratio control system for an engine for controlling an amount of a fuel mixture to be delivered into a combustion chamber so that an air-fuel ratio of the fuel mixture attains a target air-fuel ratio performs selecting one of a plurality of predetermined target air-fuel ratios according to engine operating conditions, controlling an amount of a fuel mixture so as to attain a selected target air-fuel ratio, and changing a speed at which the target air-fuel ratio is changed from one to another ratio higher with an increase in deviation of the other target air-fuel ratio from the one target air-fuel ratio.
Claims16
An air-to-fuel ratio control system for an internal combustion engine for controlling the amount of a fuel mixture to be delivered into a combustion chamber so as to bring an air-to-fuel ratio toward a target air-to-fuel ratio, said air-to-fuel ratio control system comprising:
- engine load monitoring means for monitoring an engine load at which the internal combustion engine operates;
- and
- air-to-fuel control means for setting the target air-to-fuel ratio to a predetermined lean level at which a lean fuel mixture is delivered while said engine load monitoring means monitors an engine load in a high range of engine loads higher than a specified level of engine load and to a predetermined rich level at which an enriched fuel mixture is delivered while said engine load monitoring means monitors an engine load in a low range of engine loads lower than said specified level of engine load, and varying said target air-to-fuel ratio between said lean level and said rich level faster when said engine load monitoring means monitors a change in engine load from said high range to said low range than when said engine load monitoring means monitors a change in engine load from said low range to said high range, and controlling an amount of fuel injection so as to deliver said target air-to-fuel ratio.
An air-to-fuel ratio control system for an internal combustion engine for controlling the amount of a fuel mixture to be delivered into a combustion chamber so as to bring an air-to-fuel ratio toward a target air-to-fuel ratio, said air-to-fuel ratio control system comprising:
- engine operating condition monitoring means for monitoring an engine operating condition under which the internal combustion engine operates;
- and
- air-to-fuel control means for setting the target air-to-fuel ratio to a predetermined lean level at which a lean fuel mixture is delivered while said engine operating condition monitoring means monitors an engine operating condition in a high range of engine operating conditions where engine speeds are higher than a specified speed and to a predetermined rich level at which an enriched fuel mixture is delivered while said engine operating condition monitoring means monitors an engine operating condition in a low range of engine operating conditions where engine speeds are lower than said specified speed, and varying said target air-to-fuel ratio between said lean level and said rich level faster when said engine operating condition monitoring means monitors a change in engine operating condition from said high range to said low range than when said engine operating condition monitoring means monitors a change in engine operating condition from said low range to said high range, and controlling an amount of fuel injection so as to deliver said target air-to-fuel ratio.
An air-to-fuel ratio control system for an internal combustion engine for controlling the amount of a fuel mixture to be delivered into a combustion chamber so as to bring an air-to-fuel ratio toward a target air-to-fuel ratio, said air-to-fuel ratio control system comprising:
- engine operating condition monitoring means for monitoring an engine operating condition under which the internal combustion engine operates;
- and
- air-to-fuel control means for setting said target air-to-fuel ratio to a level differently according to engine operating conditions, changing said target air-to-fuel ratio from one level to another level according to a change in engine operating condition at a rate increased with an increase in deviation in said target air-to-fuel ratio between said one level and said other level, and controlling an amount of fuel injection so as to deliver said target air-to-fuel ratio.
Dependencies are inferred from the claim text.