System Description

MANUAL AIR CONDITIONING SYSTEM


System Description


SYSTEM DESCRIPTION
- Manual air conditioner system is controlled by each function of BCM, ECM or IPDM E/R.

Control by BCM
- Compressor control

Control by ECM
- Compressor control
- Cooling fan control. System Description.
- Air conditioner cut control. System Description.

Control by IPDM E/R
- Relay control. Without I-Key.
- Cooling fan control. Without I-Key.
- Fan speed of blower fan motor is changed by the combination of fan switch operation and blower fan resistor control.

OPERATION

A/C Control
















COMPRESSOR CONTROL

Description
- BCM transmits the A/C ON signal and blower fan ON signal to ECM via CAN communication line only when the compressor operational condition is satisfied, and A/C indicator is turned ON.

NOTE:
Compressor operational condition
- Thermo control amp. signal ON
- Blower fan signal ON
- A/C switch signal ON
- ECM judges the conditions of each sensor (Refrigerant pressure sensor signal, accelerator position signal, etc.), and transmits the A/C compressor request signal to IPDM E/R via CAN communication line.
- By receiving the A/C compressor request signal from ECM, IPDM E/R turns the A/C relay to ON, and activates the compressor.

Compressor Protection Control at Pressure Malfunction
The high-pressure side value that is detected by refrigerant pressure sensor is as per the following state, ECM requests IPDM E/R to turn A/C relay OFF and stop the compressor.
- 3.12 MPa (31.8 kg/cm2, 452 psi) or more (When the engine speed is less than 1,500 rpm)
- 2.74 MPa (27.9 kg/cm2, 397 psi) or more (When the engine speed is 1,500 rpm or more)
- 0.14 MPa (1.4 kg/cm2, 20 psi) or less

Low Temperature Protection Control





- When the thermo control amp. detects that evaporator surface temperature is 2�C (36�F) or less, thermo control amp. signal becomes OFF, and stops the compressor.
- When the air temperature returns to 3.5�C (38�F) or more, the compressor is activated.

Operating Rate Control
- Thermo control amp. detects the positions of air temperature control dial and MODE dial.
- Thermo control amp. corrects the stopping temperature of A/C compressor depending on the condition of A/C operation, and prevents too much heating by turning thermo control amp. ON - OFF.

Air conditioner Cut Control
When the engine condition is high load, ECM makes the A/C relay to OFF, and stops the compressor. System Description.

SWITCHES AND THEIR CONTROL FUNCTIONS
















AIR DISTRIBUTION

Without Rear Foot Duct






With Rear Foot Duct