/ Method for determining rich/lean state of oxygen sensor by cooling water temperature

摘要

PURPOSE: A deciding method for density of an oxygen sensor according to coolant temperature is provided to control the air fuel ratio regardless of deviation of an engine by applying a feedback map according to coolant temperature. CONSTITUTION: An oxygen sensor is heated in starting an engine of a vehicle, and temperature of the oxygen sensor is detected by a sensor temperature detecting unit. Forbidden feedback time or water temperature is detected by a timer or a water temperature sensor after starting in increasing temperature of the oxygen sensor. The feedback control is performed in case of forbidden feedback time and water temperature to be over the reference values. The air fuel ratio is controlled by applying the feedback map according to temperature of coolant.