Apparatus and method for fan soft-start controller

A radiator fan soft-start controller for controlling operation of a radiator fan motor of a vehicle, wherein the radiator fan soft-start controller is communicatively coupled to an engine control module that receives engine block temperature information from an engine block temperature sensor that senses an engine block temperature of a vehicle engine block, wherein the engine control module outputs a first fan speed signal via a low-speed output connector when the engine block temperature exceeds a first temperature threshold, wherein the first fan speed signal is configured to operate the radiator fan motor at a first operating speed, wherein the engine control module outputs a second fan speed signal via a high-speed output connector when the engine block temperature exceeds a second temperature threshold, wherein the second fan speed signal is configured to operate the radiator fan motor at a second operating speed, and wherein the second operating speed of the radiator fan motor is faster than the first operating speed of the radiator fan motor, the radiator fan soft-start controller comprising:

• a low-speed fan input communicatively coupled to the low-speed output connector, wherein the low-speed fan input receives the first fan speed signal output by the engine control module;
• a high-speed fan input communicatively coupled to the high-speed output connector, wherein the high-speed fan input receives the second fan speed signal output by the engine control module;
• a pulse width modulator controllably coupled to an input of the radiator fan motor, wherein the pulse width modulator outputs a first power level that operates the radiator fan motor at the first operating speed, and wherein the pulse width modulator outputs a second power level that operates the radiator fan motor at the second operating speed;
• and
• a processor system communicatively coupled to the low-speed fan input and the high-speed fan input, and controllably coupled to the pulse width modulator,
• wherein the processor system controls the pulse width modulator to provide a first soft start of the radiator fan motor in response to receiving the first fan speed signal, wherein the first soft start is defined by a first increasing power ramp that starts at a zero-power level and ends at the first power level that operates the radiator fan motor at the first operating speed, and
• wherein the processor system controls the pulse width modulator to provide a second soft start of the radiator fan motor in response to receiving the second fan speed signal, wherein the second soft start is defined by a second increasing power ramp that starts at the zero-power level and ends at the second power level that operates the radiator fan motor at the second operating speed.