Patent ID: 9567893
Date: 2017-02-14
CPC Classifications: F01P,F02B,F02M,Y02T

Claim:
1. A method of operating a cooling system for a vehicle engine, the cooling system including a motor operable to rotate a fan and a motor controller operable to drive the motor, the method comprising: supplying electrical power to the motor controller from an electrical power source; determining if a control signal has been received by the motor controller; determining if an enable signal from a source separate from the source of the control signal has been received by the motor controller; and operating the motor controller to drive the motor at a non-zero speed if at least one of the control signal and the enable signal is received, wherein the control signal is a pulse-width modulated signal having a duty cycle ranging from 0% to 100% and wherein the non-zero speed is a predetermined speed if the control signal is received with a duty cycle that is less than a standby duty cycle and the enable signal is received by the motor controller, and wherein the standby duty cycle is 3%.