Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Tetsurou Ishida

Kazuhide Togai

Katsunori Ueda

Yoshiaki Danno

Yoshiaki Kodama

Air-to-fuel ratio control system for internal combustion engine

Control device for internal combustion engine

An air fuel ratio detecting device has an air-fuel ratio sensor for producing an air-fuel ratio information indicative of the concentration of oxygen in an exhaust gas produced by a burned air-fuel mixture in the internal combustion engine. An air-fuel ratio is calculated on the basis of the air-fuel ratio information. A pressure in the exhaust gas is calculated on the basis of pressure information depending on the pressure of the exhaust gas. The difference between the pressure and a reference pressure which acts on the air-fuel ratio sensor when the air-fuel ratio sensor is placed in a reference environment, is calculated. The air-fuel ratio is corrected with the pressure difference. The corrected air-fuel ratio is free of pressure fluctuations of the exhaust gas, and is highly reliable for accurate air-fuel ratio control. The air-fuel ratio detecting device is effective for improved fuel economy, increased engine output power, a more stable idling engine speed, purified exhaust emission, and improved drivability.

Air-fuel ratio detecting device

An air-fuel ratio control system compares an air-fuel ratio indicated by air-fuel ratio information from an air-fuel ratio sensor and a target air-fuel ratio determined depending on operating conditions of a motor vehicle which incorporates the air-fuel ratio control system, for reliably determining at least a failure of the air-fuel ratio sensor. When a failure of the air-fuel ratio sensor is detected, an air-fuel ratio feedback control process is stopped or the air-fuel ratio sensor is disabled, preventing the air-fuel ratio from being corrected in error based on an output signal from the air-fuel ratio sensor which has failed. Therefore, the air-fuel ratio control system prevents problems such as poor exhaust gas purification, reduced drivability, and unstable engine idling from taking place.

Air-fuel ratio control system

Growing community of inventors

Kyoto, Japan

Tetsurou Ishida