Automatic Aircondition Systm Airflow Temperature Control


1.Individual A/C control for left and right
In some models, the temperature and airflow control can be performed based on individual temperature setting of driver’s side and front passenger side.
The temperature and airflow control is performed in the following ways:
Control with damper
The air mix damper is fitted for the left and right to allow individual temperature control.
Control with film damper
The step motor retracts the film damper with holes and adjusts the location of the holes to allow individual temperature and airflow control.
Not all vehicles use the duct sensors for individual temperature control for the left and right vents.
In some models airflow is controlled individually for the left and right by airflow control even when the vehicle utilizes damper (plate type).

Airflow Control

When the A/C is switched between heater and cooler, the A/C mode is automatically switched for the desired airflow.
The airflow control is switched in the following way:
When lowering the interior temperature: FACE
When the interior temperature is stable around the set temperature: BI-LEVEL
When heating the interior: FOOT

Blower Speed Control

The air volume is controlled by automatic adjustment of the blower motor speed based on the gap between the interior and set temperatures.
When there is a big difference in temperature:
Hi blower motor speed
When there is a small difference in temperature:
Lo blower motor speed
2.Auto control
The current to the blower motor is controlled by adjusting the base current of the power transistor. Based on the gap between the interior and set temperatures, the blower speed is continuously controlled with TAO value.
3.EX-HI relay control
EX-HI relay directly grounds the motor when the MAX air blow is required.
As this relay avoids voltage loss of the power transistor, the “saved” voltage can be utilized to generate the maximum blower speed.
4.Manual control
The blower speed can be adjusted manually by the blower speed selector setting.
Function of LO resistor:
A large amount of current flows when the blower motor is activated. In order to protect the power transistor, LO resistor receives current first before the power transistor turns on

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