METHOD FOR DIAGNOSING ELECTRIC WATER PUMP OF A COMBUSTION ENGINE

摘要

A method for diagnosing an electric water pump of an internal combustion engine includes determining whether a present condition is a coil-open diagnosis condition that enables diagnosis of whether any coil of a sensorless 3-phase motor used in the electric water pump is open. When the coil-open diagnosis condition is satisfied, whether a coil of one phase is open is determined by using a change in phase currents. When the coil-open diagnosis condition is satisfied, whether coils of two phases are open is determined by using a magnitude of a motor torque or a magnitude of an average phase current. When the coil-open diagnosis condition is satisfied, whether any coil of the motor is open during driving of the motor is determined by using a variation in the motor torque.