Patent ID: 8396647

Claim:
A control method for an internal combustion engine mounted on a vehicle, wherein an engine idle speed control for adjusting an engine speed to a target engine speed set in accordance with an engine operation state and an engine speed reduction prevention control for rapidly increasing the engine speed to suppress stalling of the internal combustion engine when the engine speed becomes equal to or lower than a threshold engine speed, which is lower than the target engine speed, are executed when the engine is idling and the target engine speed of the engine idle speed control is reduced when a speed of the vehicle is equal to or below a predetermined vehicle speed to shift the internal combustion engine to idle operation when stopping the vehicle from traveling, the control method comprising: determining whether the vehicle is stopping from traveling and the engine is shifting to idle operation; detecting whether the vehicle is traveling on a road surface with a low friction coefficient as compared to that of a standard road surface; and reducing the target engine speed and reducing the threshold engine speed of the engine speed reduction prevention control if the vehicle is traveling on a road surface with a low friction coefficient.