Patent Document ID: 4747379
Application ID: 07089545
Patent Flag: 1

Claim One:
1. An idle speed control device for adjusting a flow passage area of a bypass passage connecting portions of an intake passage upstream and downstream of a throttle valve to control an idle speed, said idle speed control device comprising: an idle speed control valve provided in said bypass passage for changing a flow passage area thereof; means for feedback control of the degree of opening of said idle speed control valve, said feedback control means controlling the degree of opening to maintain the idle speed at a predetermined value when a predetermined feedback condition is satisfied; means for setting a learning value of the degree of opening of said idle speed control valve needed to maintain the idle speed at a predetermined value, said setting means determining said learning value when a predetermined learning condition is satisfied; and means for opening said idle speed control valve which, when said feedback condition is not satisfied, maintains the degree of opening of said idle speed control valve if the present degree of opening is larger than said learning value, and increases the degree of opening of said idle speed control valve to said learning value if the present degree of opening is smaller than said learning value.