Air-fuel ratio control method for internal combustion engine

Abstract

Abstract PURPOSE:To estimate the actual engine temperature accurately by estimating the high temperature state of an engine for judging the feedback control of the air-fuel ratio on the basis of the engine speed, the load and the air-fuel ratio of supplied mixture. CONSTITUTION:An engine control unit 5 feedback-controls the fuel injection quantity from a fuel injection valve 6 in such a way that the air-fuel ratio becomes the specified value according to the exhaust gas component density detected at an O2 sensor 15, as well as stops the feedback control and enriches the air-fuel ratio of mixture when an engine 1 is detected to be in the state of the specified high load and high temperature. In this case, the temperature of the engine 1 is estimated on the basis of the engine speed by a sensor 11, the engine load (fuel injection quantity) and the air-fuel ratio of the supplied mixture. The actual engine temperature can be thus estimated accurately so as to perform the appropriate enrichment of the air-fuel ratio and thereby prevent the excessive rise of catalytic temperature.

Inventors

• 👤 Fumio Hosoda
• 👤 細田　文男
• 👤 Yukito Fujimoto
• 👤 藤本　幸人
• 👤 Katsushi Watanabe
• 👤 渡辺　勝志
• 👤 Atsuo Fujii
• 👤 藤井　厚雄
• 👤 Yasunari Seki
• 👤 関　康成
• 👤 Shigeto Kashiwabara
• 👤 柏原　重人

Bibliographic Details