Patent ID: 9515585
Filing Date: 2016-12-06
CPC Classification: G01R,H02P

Claim Text:
1. A method for diagnosing an electric water pump of an internal combustion engine, comprising steps of: a) determining whether a present condition of the electric water pump 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; b) determining whether a coil of one phase is open by using a change in phase currents when the coil-open diagnosis condition is satisfied; c) determining whether coils of two phases are open by using a magnitude of a motor torque or a magnitude of an average phase current when the coil-open diagnosis condition is satisfied; and d) determining whether any coil of the motor is open during driving of the motor by using a variation in the motor torque when the coil-open diagnosis condition is satisfied.