Diesel Data: Automotive Repair

System Outline

System Outline

Air conditioning system operates when SW of multi-display or that of steering wheel is turned on. Turning on the SW sends signal to A/C control assembly, running the air conditioning system.

1. Heater Blower Operation

Manual operation
When the blower speed is set to a certain level using the blower control SW, the A/C control assembly sends the signals to the blower control to control the blower motor speed.

Auto operation
When the auto SW is pushed, the A/C control assembly calculates necessary blower speed from setting of SWs and input of the sensors and sends the signals to the blower control to automatically control the blower motor speed.

2. Air Inlet Control Servo Motor Control
When the FRESH/RECIRC select SW is set to RECIRC, the air inlet control servo motor starts rotating to move the damper toward the RECIRC side. The damper position is detected by the TERMINAL TPI of the A/C control assembly. The motor continuously rotates until the damper reaches its stop position. When the FRESH/RECIRC select SW is set to FRESH, the air inlet control servo motor starts rotating to move the damper toward the FRESH side. The damper position is detected by the TERMINAL TPI of the A/C control assembly. The motor continuously rotates until the damper reaches its stop position. In auto mode, A/C control assembly controls the damper to move to the best position for the conditions without operating the mode select SW.

3. Air Vent Mode Control Servo Motor Control
When the mode select SW is pushed, the ECU in the A/C control assembly activates the air vent mode control servo motor. The servo motor rotates to the position (FACE, BI-LEVEL, FOOT, FOOT/DEF, DEF) selected by using the mode select SW, and moves the damper.
In auto mode, A/C control assembly controls the damper to move to the best position for the conditions without operating the mode select SW.

4. Air Mix Control Servo Motor Control
Based on the set temperature by the temperature control SW, the ECU in the A/C control assembly sends a signal to the air mix control servo motor. This signal drives the motor to reach the temperature set by the temperature control SW, and moves the film damper.

5. Humidity Sensor Control
A/C control assembly detects humidity in passenger room when A/C is turned on, with humidity detecting function of A/C room temperature sensor and controls to dehumidify for comfortable condition.

6. Air Conditioning Operation
A/C control assembly calculates target cooled temperature from information such as that of operating SWs, room temperature, humidity, ambient temperature and insolation to have target running speed of compressor assembly (Motor). The calculated control signal is sent to inverter to drive compressor assembly (Motor) (Electric motor) with control of inverter, resulting in operating A/C.