Air-fuel ratio learning control device for electronically controlled fuel injection internal combustion engines

Abstract

Abstract PURPOSE:To obtain stable controllability of an engine, by executing learning control to converge the base air-fuel ratio to lambda=1 (lambda is the excess air ratio), and thereby minimizing deviation of the excess air ratio from lambda=1 caused by the change of the base air- fuel ratio at the time of transient operation of the engine. CONSTITUTION:The base injection quantity Tp is calculated by an arithmetic means 1 from the engine speed N and the quantity Q of intake air, and comparison is made between the actual air-fuel ratio detected by an O2-sensor and the theoretical air-fuel ratio. Further, an air-fuel ratio feedback correction factor alpha is determined by a correction factor determining means 2 by way of proportional plus integral control, and a learning correction factor alphaL stored in an RAM to correspond to the conditions of engine operation is searched at a searching means 3. The learning correction factor alphaL is renewed successively by adding a certain part of the deviation DELTAalpha between the correction factor alpha and a reference value to the learning correction factor alphaL by a renewing means 4, and then the injection quantity Ti is calculated by an arithmetic means 5 by correcting the base injection quantity Tp by use of the renewed data and the correction factor alpha.

Inventors

• 👤 Naomi Tomizawa
• 👤 富澤　尚己

Bibliographic Details