Air-fuel ratio control device

Abstract

Abstract PURPOSE:To control the air-fuel ratio properly in an air-fuel ratio feedback control method which uses an air-fuel ratio sensor, by forming a judgement in a simple and accurate manner on the basis of the activity judgement which is made according to whether the amplitude of the air-fuel ratio sensor output is held to a prescribed value. CONSTITUTION:When an internal combustion engine is operated, firstly, the outputs of a suction air temperature sensor 20 and a cooling water temperature sensor 21 are accepted to a control circuit 24 in which a first correction value K1 is calculated and stored. Secondly, the output of an air-fuel sensor 22 is inputted to the control circuit 24 and a second correction value, that is a feedback correction value K2 as the function of the time elapsed is added to or subtracted from the first correction value K1. Subsequently, a third correction value, that is a learning correction value K3 is calculated to be added or subtracted. In the operation, the output of the air-fuel ratio sensor 22 is compared with a prescribed monitor level and when the output remains either side above or below the monitor level until a prescribed time is elapsed, the air-fuel ratio sensor 22 is judged as to be inactive. When it is judged as active, a correction value corresponding to the suction air quantity is obtained by using the above correction value K2.

Inventors

• 👤 Takashi Kaji
• 👤 恭士 梶
• 👤 Shigenori Isomura
• 👤 磯村　重則
• 👤 Toshio Kondo
• 👤 利雄 近藤

Bibliographic Details