Patent ID: 7950368

Claim:
A method for controlling an engine of a vehicle, the method comprising: cold starting an engine; during a first idle speed control mode when catalyst temperature is below a first predetermined threshold, setting a spark timing to a first nominal value retarded from a peak torque timing, and adjusting spark timing about the first nominal timing while maintaining spark timing retarded from the peak torque timing, said adjusting including advancing spark timing from the first nominal timing in response to decreases in engine idle speed; and during a second idle speed control mode when catalyst temperature is above the first predetermined threshold and engine coolant temperature is below a second predetermined threshold, setting the spark timing to a second nominal value advanced from the peak torque timing, and adjusting spark timing about the second nominal timing while maintaining spark timing advanced from the peak torque timing, said adjusting including retarding spark timing from the second nominal timing in response to decreases in engine idle speed.