Patent ID: 8739564

Claim:
A method for controlling a fan that cools devices of a vehicle comprising: (a) comparing the current temperatures of at least first and second said devices to multiple temperature ranges of each of said devices and determining on the basis of said comparisons whether fan speed should be decreased, increased by a step change, increased over time or maximized; (b) increasing fan speed to a maximum fan speed if at least one of said comparisons indicates that the maximum fan speed is desired; (c) increasing fan speed in a step change to a reference fan speed if at least one of said comparisons indicates that a step increase in fan speed is desired; (d) increasing fan speed to a reference fan speed at a reference rate of change if at least one of said comparisons indicates that an increase in fan speed over time is desired; (e) decreasing fan speed to a reference fan speed if said comparisons indicate that a decrease in fan speed is desired; (f) determining a first magnitude of power required to drive a compressor of a refrigeration system and the fan at a first speed; (g) increasing fan speed to a second fan speed and determining a second magnitude of power required to drive the compressor and the fan at the second fan speed; (h) if the first magnitude of power is greater than the second magnitude of power, increasing the fan speed to the second fan speed at a desired rate; and if the first magnitude of power is less than the second magnitude of power, decreasing the fan speed at a desired rate.