Air-fuel ratio controlling apparatus

Abstract

Abstract PURPOSE:To raise the accuracy of air-fuel ratio control, by determining a target exhaust temperature on the basis of the intake temperature and the conditions of engine operation, and feed-back controlling the air-fuel ratio to keep the exhaust temperature of an engine at said target exhaust temperature. CONSTITUTION:In operation of an engine, a target base exhaust temperature TEMH is determined from the air-flow rate QA and the engine speed N in a taget-value determining means 21, and then a target exhaust temperature TEM is obtained by correcting the target base exhaust temperature TEMH on the basis of the cooling-water temperature TW and the intake temperature TA representing the conditions of engine operation. Thereafter, comparison is made between the target exhaust temperature TEM and the actual exhaust temperature TE in a comparing means 22, and a base pulse width TPO is calculated in a base pulse width calculating means 23 on the basis of the air-flow rate QA and the engine speed N. Further, a required pulse width TI is obtained by correcting the base pulse width TPO by use of a correction factor or the like that is determined by a correction factor determining means 25 according to the result of the above comparing means 22 and a control zone judging means 24 which judges whether fuel supply is interrupted.

Inventors

• 👤 Hatsuo Nagaishi
• 👤 初雄 永石
• 👤 Takeshi Kitahara
• 👤 剛 北原

Bibliographic Details