Honda Giken Kogyo Kabushiki Kaisha

Hiroki Munakata

Norio Suzuki

Shusuke Akazaki

Yusuke Hasegawa

Masuhiro Yoshizaki

Koichi Fujimori

Akira Kato

Hiroshi Kitagawa

Yoichi Nishimura

Naoto Fujimura

Yuh Yoshii

Kouichi Saiki

An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor arranged in the exhaust system of the engine. An ECU estimates the air-fuel ratio of a mixture supplied to each of the cylinders cylinder by cylinder in response to an output from the air-fuel ratio sensor, by using an observer for observing an internal operative state of the exhaust system, based on a model representative of the behavior of the exhaust system, and calculates cylinder-by-cylinder air-fuel ratio control amounts corresponding respectively to the cylinders for carrying out feedback control of the air-fuel ratio of the mixture supplied to each of the cylinders such that the estimated air-fuel ratio of the mixture supplied to each of the cylinders is converged to a desired value. Upper and lower limit values of the cylinder-by-cylinder air-fuel ratio control amounts are set according to at least one of an rotational speed change amount of the engine and atmospheric pressure, and the cylinder-by-cylinder air-fuel ratio control amounts are limited so as to fall within an allowable range defined by the upper and lower limit values.

Air-fuel ratio control system for internal combustion engines

An air-fuel ratio control system for an internal combustion has a plurality of cylinders and an exhaust system. The air-fuel ratio of exhaust gases emitted from the cylinders is detected by an air-fuel ratio sensor arranged in the exhaust system. The air-fuel ratio of a mixture supplied to each of the cylinders is estimated based on an output from the air-fuel ratio sensor by using an observer for observing an internal operative state of the exhaust system by means of a model representative of a behavior of the exhaust system. Feedback control of an amount of fuel to be supplied to the each of the cylinders is carried out in response to the output from the air-fuel ratio sensor by using a controller of a recurrence formula type, such that the air-fuel ratio of the mixture supplied to the each of the cylinders is converged to a desired value. The controller of the recurrence formula type adjusts adaptive parameters for use in the feedback control, for the each of the cylinders based on the estimated air-fuel ratio.

There is provided an air-fuel ratio control system for an internal combustion. An air-fuel ratio sensor arranged in the exhaust system detects an air-fuel ratio of exhaust gases emitted from the engine. An amount of fuel to be supplied to the engine is controlled in response to the output from the air-fuel ratio sensor by using a controller of a recurrence formula type, such that an air-fuel ratio of a mixture supplied to the engine is converged to a desired air-fuel ratio, to thereby effect feedback control of the air-fuel ratio of the mixture. The desired air-fuel ratio is determined based on operating conditions of the engine. The desired air-fuel ratio is smoothed when the engine is in a predetermined operating condition. The feedback control of the air-fuel ratio is carried out by the use of the smoothed desired air-fuel ratio.

There is provided an air-fuel ratio control system for an internal combustion engine installed on an automotive vehicle. The control system controls the air-fuel ratio of a mixture supplied to the engine to a value leaner than a stoichiometric air-fuel ratio immediately after the start of the engine. Operating conditions of the engine and/or operating conditions of the automotive vehicle is detected. Starting of the vehicle is predicted based on the detected operating conditions of the engine and/or the detected operating conditions of the automotive vehicle. The air-fuel ratio of the mixture supplied to the engine is changed to a richer value than the leaner value when the starting of the vehicle is predicted.

Air-fuel ratio control system having function of after-start lean-burn

A suction air control apparatus of an internal combustion engine which is subjected to an after-start lean-burn control to be operated at a lean mixture ratio rather than a theoretical mixture ratio is provided. According to the apparatus, a smooth operation of the engine in a transitional state when the after-start lean-burn control is canceled is ensured. The apparatus comprises throttle opening degree control means for driving a throttle valve of a suction system to control a throttle opening degree to a target throttle opening degree set in accordance with an operation state of the engine for regulating amount of the suction air, after-start lean-burn control cancel discrimination means for discriminating cancellation of the after-start lean-burn control of the engine, steep acceleration discrimination means for discriminating whether an acceleration of a vehicle is a steep acceleration higher than a predetermined acceleration or not, and throttle opening degree correction means for correcting the target throttle opening degree to limit increase of the target throttle opening degree when the after-start lean-burn control cancel discrimination means discriminates cancellation of the after-start lean-burn control and the steep acceleration discrimination means discriminates the steep acceleration of the vehicle.

Suction air control apparatus of internal combustion engine

There is provided an air-fuel ratio control system for an internal combustion engine installed on an automotive vehicle. The control system controls the air-fuel ratio of a mixture supplied to the engine to a value leaner than a stoichiometric air-fuel ratio immediately after the start of the engine. Operating conditions of the engine and/or operating conditions of the automotive vehicle are detected. Starting of the vehicle is predicted based on the detected operating conditions of the engine and/or the detected operating conditions of the automotive vehicle. The air-fuel ratio of the mixture supplied to the engine is changed to a richer value than the leaner value when the starting of the vehicle is predicted.

A fuel supply control system for an internal combustion engine calculates a basic amount of fuel to be supplied to the engine, based on the rotational speed of the engine and load on the engine. An amount of fuel adhering to the inner wall surface of the intake passage of the engine is estimated to calculate an adherent fuel-dependent correction amount. An amount of fuel carried off from the inner wall surface of the intake passage into at least one combustion chamber of the engine is estimated to calculate a carried-off fuel-dependent correction amount. The basic amount of fuel is corrected such that the air-fuel ratio of a mixture supplied to the engine becomes equal to a desired air-fuel ratio determined depending on operating conditions of the engine to obtain a corrected basic fuel amount, and at the same time the corrected basic fuel amount is corrected by the use of the adherent fuel-dependent correction amount and the carried-off fuel-dependent correction amount to calculate an amount of fuel to be supplied to the engine. At least one of the adherent fuel-dependent correction amount and the carried-off fuel-dependent correction amount is corrected according to the desired air-fuel ratio.

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Wako, Japan

Hiroki Munakata