Patent Document ID: 6016787
Application ID: 09109095
Patent Flag: 1

Claim One:
1. An idle rotation speed learning control apparatus of an engine in which a target air-fuel ratio is set to a leaner value than a theoretical air-fuel ratio in a predetermined driving region including at least an idle state, the apparatus comprising: an idle rotation speed learning control means for learning a decreasingly changed portion of an opening area by age in an intake system of the engine based on the result of performing a feedback control of an intake air quantity of said engine so as to approximate an engine rotation speed to a target idle rotation speed during an idle drive, and in response to said learned results, controlling the intake air quantity during said idle drive; and a lean burn prohibition means for prohibiting the combustion in said lean air-fuel ratio and setting said target air-fuel ratio forcibly to said theoretical air-fuel ratio when the learning by said idle rotation speed learning control means is performed.