Air Conditioner Control
AIR CONDITIONER CONTROLOverview Air Conditioner LAN Control System
The LAN (local area network) system consists of front air control, air mix door motor, intake door motor, and mode door motor.
A configuration of these components is shown in the diagram.
System Construction
A small network is constructed between the front air control, air mix door motor, intake door motor, and mode door motor. The front air control and motors are connected by data transmission lines and motor power supply lines. The LAN network is built through the ground circuits of the two motors.
Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted through the data transmission lines connecting the front air control and each motor.
The following functions are contained in LCUs built into the air mix door motor, intake door motor, and the mode door motor.
- Address
- Motor opening angle signals
- Data transmission
- Motor stop and drive decision
- Opening angle sensor (PBR function)
- Comparison
- Decision (front air control indicated value and motor opening angle comparison)
Operation
The front air control receives signals from its various dials and switches. The front air control then sends air mix door, mode door and intake door opening angle data to the air mix door motor LCU, mode door motor LCU and intake door motor LCU.
The air mix door motor, mode door motor and intake door motor read their respective signals according to the address signal. Opening angle indication signals received from the front air control and each of the motor position sensors are compared by the LCUs in each motor with the existing decision and opening angles. Subsequently HOT/COLD, DEFROST/VENT or FRESH/RECIRCULATION operation is selected. The new selection data is returned to the front air control.
Transmission Data and Transmission Order
Front air control data is transmitted consecutively to each of the door motors following the form shown in given figure.
Start: Initial compulsory signal sent to each of the door motors.
Address: Data sent from the front air control is selected according to data-based decisions made by the air mix door motor, mode door motor and intake door motor. If the addresses are identical, the opening angle data and error check signals are received by the door motor LCUs. The LCUs then make the appropriate error decision. If the opening angle data is normal, door control begins.
If an error exists, the received data is rejected and corrected data received. Finally, door control is based upon the corrected opening angle data.
Opening angle: Data that shows the indicated door opening angle of each door motor.
Error check: Procedure by which sent and received data is checked for errors. Error data is then compiled. The error check prevents corrupted data from being used by the air mix door motor, mode door motor and intake door motor. Error data can be related to the following problems.
- Abnormal electrical frequency
- Poor electrical connections
- Interference from other signal transmission lines
- Signal level fluctuation
Stop signal: At the end of each transmission, a stop operation, in-operation, or internal problem message is delivered to the front air control. This completes one data transmission and control cycle.
Air Mix Door Control
The air mix door is controlled by the front air control based on input from the temperature dial setting.
Blower Speed Control
Blower speed is controlled by the front air control based on the position of the blower control dial. With the blower control dial set to any position except OFF, the blower will begin to operate.
Intake Door Control
The intake door is controlled by the front air control based on input from the recirculation switch setting, and the MAX A/C switch setting.
Mode Door Control
The mode door is controlled by the front air control based on input from the mode dial setting.
Magnet Clutch Control
The ECM controls compressor operation using input signals from the throttle position sensor and front air control.
Overview of Control system
The control system consists of an input sensor, switches, the front air control and outputs.
The relationship of these components is shown in the diagram given:
Control Operation
AIR CONDITIONER (A/C) SWITCH
The air conditioner switch controls the A/C system. When the switch is pressed with the blower ON, the compressor will turn ON. The indicator lamp will also illuminate.
The air conditioner cooling function operates only when the engine is running.
TEMPERATURE DIAL (Potentio Temperature Control)
Increases or decreases the set temperature.
BLOWER CONTROL DIAL/OFF SWITCH
Manually controls the blower speed.
In the off position, the compressor and blower are OFF, the intake door is set to the chosen position, and the air mode doors are set to the chosen position.
RECIRCULATION ( ) SWITCH
DEFROSTER SWITCH
Positions the air mode doors to the defrost position. Also positions the intake doors to the outside air position. The compressor remains ON until the ignition is turned OFF or if the customer turns the mode to a non-defrost mode and turns the A/C button to OFF.
MODE DIAL
Controls the air discharge through control of mode door, also controls MAX A/C function.
REAR WINDOW DEFOGGER SWITCH
This switch turns the rear window defogger ON and OFF.
Discharge Air Flow
System Description
SWITCHES AND THEIR CONTROL FUNCTION
CAN Communication System Description
Refer to Information Bus.