Air-fuel ratio controller for internal combustion engine

Abstract

Abstract PURPOSE:To reduce the exhaust emission and reduce the abnormal odor of catalyst exhaust by installing air-fuel ratio sensors on the upstream and downstream sides of a catalyst and varying the comparison voltage of the downstream side sensor according to the load. CONSTITUTION:Air-fuel ratio sensors 13 and 15 are installed on the upstream and downstream sides of a catalytic converter 12 in an exhaust pipe 11. A controller 10 detects the engine load by receiving the signal of an air flow meter 3, and varies the comparison voltage of the second air-fuel ratio sensor 15 according to the load. Further, the air-fuel ratio is controlled according to the result of the comparison of the both air-fuel ratio sensors 13 and 15 with each comparison voltage. In other words, the control to the rich side is performed in case of a high load, and control to the lean side is performed in case of a low load. Thus, the exhaust emission and abnormal exhaust door of catalyst can be reduced.

Inventors

• 👤 Nobuaki Kashiwanuma
• 👤 栢沼　信明
• 👤 Toshinari Nagai
• 👤 俊成 永井

Bibliographic Details