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US 4,475,517 AGranted
Air-fuel ratio control method and apparatus for an internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsNobuyuki Kobayashi, Hiroshi Itoh, Yoichi Sugiura
Life of this patent
Estimating the term…
Abstract
The proportion constant for proportional calculation and/or the integration time-constant for integral calculation with respect to the air-fuel ratio correction factor is changed in accordance with the engine warm-up condition, and the fuel-feeding rate is controlled in accordance with the calculated air-fuel ratio correction factor.
Claims8
An air-fuel ratio control method of an internal combustion engine, comprising the steps of:
- detecting the concentration of a predetermined component in the exhaust gas to generate a first electrical signal which indicates whether the air-fuel ratio in the engine is on the rich side or on the lean side with respect to the stoichiometric condition;
- detecting the warm-up condition of the engine to generate a second electrical signal which indicates the detected warm-up condition;
- calculating a proportional plus integral value of said first electrical signal to produce an air-fuel ratio correction factor which corresponds to said proportional plus integral value, at least one of the proportion constant of proportional calculation and the integration time-constant of integral calculation being changed in accordance with said second electrical signal, so that the proportion constant, when changed, being made greater when the engine is fully warmed-up than when the engine is warming-up, the integration time-constant, when changed, being made smaller when the engine is fully warmed-up than when the engine is warming-up, causing said air-fuel ratio correction factor to change more quickly in response to change of said first electrical signal when the engine is fully warmed-up than when the engine is warming-up;
- and
- correcting the feeding rate of the fuel supplied to the engine in accordance with said air-fuel ratio correction factor.
2 more elements
An air-fuel ratio control apparatus of an internal combustion engine, comprising:
- means for detecting the concentration of a predetermined component in the exhaust gas to generate a first electrical signal which indicates whether the air-fuel ratio in the engine is on the rich side or on the lean side with respect to the stoichiometric condition;
- means for detecting the warm-up condition of the engine to generate a second electrical signal which indicates the detected warm-up condition;
- means for calculating a proportional plus integral value of said first electrical signal to produce an air-fuel ratio correction factor which corresponds to said proportional plus integral value, at least one of the proportion constant of proportional calculation and the integration time-constant of integral calculation being changed in accordance with said second electrical signal, so that the proportion constant, when changed, being made greater when the engine is fully warmed-up than when the engine is warming-up, the integration time-constant, when changed, being made smaller when the engine is fully warmed-up than when the engine is warming-up, causing said air-fuel ratio correction factor to change more quickly in response to change of said first electrical signal when the engine is fully warmed-up than when the engine is warming-up;
- and
- means for correcting the feeding rate of the fuel supplied to the engine in accordance with said air-fuel ratio correction factor.
2 more elements
Dependencies are inferred from the claim text.