COOLING FAN CONTROL

id304000201200


Outline

•  The PCM rotates the cooling fan according to the vehicle conditions for improved reliability and cooling/heating performance of the EV system.

Block Diagram

a30zzn00001191

Operation


Coolant temperature conditions

During READY on:
•  The PCM controls the output duty ratio according to the coolant temperature so that the EV system component parts do not exceed the temperature for correct operation.
•  The PCM fixes the output duty ratio in a part of the high-speed rotation range to reduce unpleasant cooling fan operation noise fluctuations.
•  When the PCM detects a coolant temperature sensor malfunction, it operates the cooling fan at maximum speed (duty ratio 90%).
During READY off:
•  When the user charges the high voltage battery externally and the climate control timer control is operated, the PCM controls the output duty ratio according to the coolant temperature so that the EV system component parts do not exceed the temperature for correct operation.
•  The PCM operates the cooling fan at an extremely low speed before transitioning to control of the output duty ratio based on the climate control timer control, charging, and power supply conditions, thereby preventing injury due to user involvement.


Climate control conditions

•  During climate control operation (A/C switch on) or high voltage battery cooling, the PCM controls the operation according to the requested duty ratio from the heat pump control unit.
Cooling and high voltage battery cooling operation:
•  During cooling and high voltage battery cooling, the PCM determines the required airflow (duty ratio) of the cooling fan based on the refrigerant pressure and vehicle speed.
•  When heating with the heat pump, the PCM determines the required air volume (duty ratio) from the refrigerant temperature at the condenser outlet in the electric motor compartment and vehicle speed.
•  During the heat pump defrosting operation at low ambient temperatures, the cooling fan operation is stopped (duty ratio 0%) to ensure heating performance.


High-voltage part temperature conditions

•  If the temperature of a high voltage part is high, the PCM operates the cooling fan at maximum speed (90% duty ratio) until the temperature decreases to the appropriate temperature for part protection and assuring drivability.