Patent ID: 6128948
Filing Date: 2000-10-10
Classification: G01M

Abstract:
A method for diagnosing warm-up behavior of a cooling system of an internal combustion engine of a vehicle upon start of the engine, comprising the steps of:a) setting a target temperature for a coolant of a cooling system of an engine;b) measuring a start-up temperature of the coolant;c) measuring engine run time since engine start;d) determining a present ambient air temperature;e) calculating a present threshold amount of energy needed to be produced by the engine to raise the coolant temperature from the start-up temperature to the target temperature;f) determining a present actual amount of energy produced by the engine since engine start;g) comparing present coolant temperature to the target temperature;h) comparing the present threshold amount of energy to the present actual amount of energy; andi) continuously repeating steps c) through h);wherein a pass report is generated when the present coolant temperature is at least equal to the target temperature, and the present threshold amount of energy is at least equal to the present actual amount of energy, and the engine run time is less than a predetermined maximum engine run time.