Cooled Seat Operation

When the cool seat switch is pressed for High Cool, the CCSM will transition to the COOL state. In response to this command, the CCSM applies a pre-determined voltage through the ventilation module cool control circuits to the cool side of the TEDs while providing a ground through the ventilation module heat control circuits to the heat side of the TEDs. A pre-determined voltage is also applied to the blower motors. The CCSM uses the following sequence, beginning with the Cool SoftStart Mode, to achieve the set point temperature before it can enter the Open Loop Cool Mode.

• Cool SoftStart Mode - The intent of the Cool SoftStart Mode is for the CCSM to bring the TED fin temperature to maximum cool temperate. The CCSM does this by setting the blower motor speed control voltage to 0 V, while ramping up the TED voltage duty cycle from 0 V to maximum voltage duty cycle over a period not to exceed 5 seconds. Then, with the TEDs at maximum voltage, the CCSM will increase the blower speed to maximum voltage, and keep these settings for the MAX COOL DURATION. After which the system transitions to the Open Loop Cool Mode.
• Open Loop Cool Mode - At the completion of Cool SoftStart Mode, the CCSM will initiate Open Loop Cool Mode. The intent of this mode is to maintain the set point fin temperature based on the input of the cool seat switch. First, by controlling the speed of the blower motor, then secondly, by controlling TED voltage. The CCSM updates these voltages once every second.