AIRFLOW TEMPERATURE CONTROL OPERATION


BHE074061190T06

Airflow Temperature Automatic Control

• The A/C amplifier calculates the air mix actuator opening angle (airflow temperature) by adding the correction input from the ECT sensor and evaporator temperature sensor to the target temperature that was calculated based on the set temperature and input from each sensor, operating the actuator.

• The actuator opening angle moves towards MAX COLD as the input temperature (heater core temperature) from the ECT sensor increases, and it moves towards MAX HOT as the input temperature from the evaporator temperature sensor (evaporator temperature) decreases.

1
A/C amplifier
2
Target temperature
3
Air mix actuator opening angle calculation
4
ECT sensor
5
Evaporator temperature sensor
6
Air mix actuator

Correction

Air mix actuator opening angle correction

• The A/C amplifier maintains the actuator at the opening angle calculated based on the position signal from the potentiometer inside the air mix actuator.

1
A/C amplifier
2
Position signal
3
Air mix actuator
4
Operating
5
Stopped
6
Target opening angle-actual opening angle

MAX HOT and MAX COLD correction

• When the set temperature is at 32.0, the air mix actuator becomes fully open, when it is at 18.0, it becomes fully closed.