System Description

AIR MIX DOOR CONTROL SYSTEM


System Description

The air mix doors are automatically controlled so that in-vehicle temperature is maintained at a preset value by the temperature setting, ambient temperature, intake temperature, in-vehicle temperature and amount of sunload.

SYSTEM OPERATION
- The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp. sends air mix doors, mode door and intake door opening angle data to the air mix door motor LCUs, mode door motor LCU and intake door motor LCU.
- The air mix door motors, mode door motor and intake door motor read their respective signals according to the address signal. Opening angle indication signals received from the unified meter and A/C amp. and each of the motor position sensors are compared by the LCUs in each door motor with the existing decision and opening angles. Subsequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection data are returned to the unified meter and A/C amp.

Door Motor Circuit






Air Mix Door Control Specification





When ignition switch is ON, unified meter and A/C amp. continuously and automatically controls temperatures regardless of air conditioning system operational condition. When setting a target temperature with temperature control dial, unified meter and A/C amp. corrects the set temperature and decides a target air mix door opening angle.
Unified meter and A/C amp. controls air mix door according to the target air mix door opening angle and current air mix door opening angle for keeping an optimum air mix door opening angle. When a temperature is set at 18.0�C (60�F), air mix door is fixed at full cold, and when a temperature is set at 32.0�C (90�F), it is set at full hot.

Potentio Temperature Control (PTC)





The PTC (1) is built into the preset switch. It can be set at an interval of 0.5�C (1.0�F) in the 18.0�C (60�F) to 32.0�C (90�F) temperature range by turning temperature control dial. The set temperature is displayed.