Fuel supply control device in internal-combustion engine

Abstract

Abstract PURPOSE:To improve the distribution of air-fuel ratio among engine cylinders to improve the output performance of an engine, by discriminating whether the air-fuel ratio of mixture is rich or lean for every engine cylinder in accordance with the concentration of O2 component in exhaust gas to compensate the amount of fuel injection from an auxiliary injection valve for each cylinder. CONSTITUTION:The output of an O2 sensor is composed of a low frequency component due to feed-back control and a high frequency component which varies discontinuously in accordance with the exhaust strokes of engine cylinders. Accordingly, the output of the O2 sensor indicates the air-fuel ratio of each cylinder for each cycle period of the high frequency component. The output of a band path filter (BPF) which is a high frequency component extracted from the output of the band path filter is compared with the averaged value VR of the O2 sensor to discriminate whether the mixture is rich or lean. The timing of the high frequency component of output of the O2 sensor varies relative to the timing of a crank angle sensor, depending upon the time during which exhaust gas flows from an exhaust valve to the attachment section of the O2 sensor. The air-fuel ratio for each engine is determined for each timing of the output of the exhaust valve, thereby the amount of fuel injection from an auxiliary injection valve is compensated.

Inventors

• 👤 Toshinari Nagai
• 👤 俊成 永井
• 👤 Shoji Watanabe
• 👤 昭二 渡辺

Bibliographic Details