Honda Giken Kogyo Kabushiki Kaisha

Naoto Fujimura

Yuji Yasui

Akira Kato

Hiroshi Maruyama

Hiroki Munakata

Akihiro Shinjo

Tatsuhito Esaki

Atsushi Ishii

Yuh Yoshii

An air fuel ratio controller for an internal combustion engine includes an exhaust gas sensor, an identifier and a control unit. The exhaust gas sensor detects oxygen concentration of exhaust gas. The identifier calculates model parameters for a model of a controlled object based on the output of the exhaust gas sensor. The controlled object includes an exhaust system of the engine. The control unit is configured to use the model parameters to control the air-fuel ratio so that the output of the exhaust gas sensor converges to a desired value, and to stop the identifier from calculating the model parameters during and immediately after the engine operation with a lean air-fuel ratio. The calculation of the model parameters may be also stopped during and immediately after fuel-cut operation that stops fuel supply to the engine. Such a stop of the calculation of the model parameters reduces the emission of undesired substances contained in exhaust gas when the engine shifts from lean operation to stoichiometric/rich operation.

Air fuel ratio controller for internal combustion engine for stopping calculation of model parameters when engine is in lean operation

A control system for an internal combustion engine having an exhaust system provided with a catalyst is provided. The control system comprises a catalyst temperature rise accelerating control in which the intake air amount is increased and the ignition timing is retarded according to the engine rotational speed. A transient control from the catalyst temperature rise accelerating control to the normal control, is started when the speed of a vehicle driven by the engine reaches a predetermined vehicle speed or higher during the catalyst temperature rise accelerating control. During the transient control, the intake air amount is gradually reduced and the ignition timing is set according to the vehicle speed.

Control system for internal combustion engine

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.

Air-fuel ratio control system for internal combustion engines

Growing community of inventors

Wako, Japan

Naoto Fujimura