JPS6469752A - Air-fuel ratio learning controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the idle stability by carrying out the air-fuel ratio learning independently in opening and closing of a bypass passage which makes a detour around a throttle valve and separately using two learned correction values, in the constitution in which said bypass passage is opening/closing-controlled according to the increase/ decrease of the load outside an engine. CONSTITUTION:An opening/closing means A which opening/closing-controls a bypass passage which makes a detour around a throttle valve in an intake passage according to the increase/decrease of the load outside an engine is installed, and when the bypass passage is opened, the fundamental fuel injection quantity set by a setting means C is corrected towards increase by an increased quantity correcting means B. In this case, the correction value for correcting the fundamental fuel injection quantity which is corrected towards increase is learned and set on the basis of the air-fuel ratio deviation by the second learned correction value setting means E. When the bypass is closed, the correction quantity for correcting the fundamental fuel injection quantity is learned and set according to the air-fuel ratio deviation by the first learned correction quantity setting means D. Then, the fuel injection quantity is set by correcting the fundamental fuel injection quantity according to each correction quantity.