Compressor Control

SYSTEM

MANUAL AIR CONDITIONING SYSTEM : Compressor Control


DESCRIPTION

- When A/C switch signal is received from front air control, the thermo control amp. transmits A/C ON signal to the BCM according to evaporator fin temperature.
- When the front blower motor is operated, the front air control transmits blower fan ON signal to the BCM.
- BCM transmits the A/C ON signal and blower fan ON signal to ECM via CAN communication line. Refer to
"CAN COMMUNICATION : System Description" CAN Communication
- 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. Refer to "RELAY CONTROL SYSTEM : System Description" IPDM E/R (Without I-Key)

CONTROL BY THERMO CONTROL AMP.

Low Temperature Protection Control





- When thermo control amp. detects that evaporator fin temperature is 1.5�C (35�F) or less, thermo control amp. switches A/C ON signal to OFF and stops the compressor.
When the evaporator fin temperature returns to 3�C (37�F) or more, the compressor is activated.

CONTROL BY ECM

Refrigerant Pressure Protection
The refrigerant system is protected against excessively high- or low-pressures by the refrigerant pressure sensor, located on the liquid tank on the condenser. The refrigerant pressure sensor detects the pressure inside the refrigerant line and sends a voltage signal to the ECM. If the system pressure rises above or falls below the following values, the ECM requests the IPDM E/R to de-energize the A/C relay and disengage the compressor.
- 3.12 MPa (31.82 kg/cm2, 452.4 psi) or more (When the engine speed is less than 1,500 rpm)
- 2.74 MPa (27.95 kg/cm2, 397.3 psi) or more (When the engine speed is 1,500 rpm or more)
- 0.14 MPa (1.43 kg/cm2, 20.3 psi) or less
Compressor Oil Circulation Control
When the engine starts while the engine coolant temperature is 56�C (133�F) or less, ECM activates the compressor for approximately 6 seconds and circulates the compressor oil once.
Air Conditioning Cut Control
When the engine is under a high load condition, the ECM transmits an A/C relay OFF request to IPDM E/R, and stops the compressor. Refer to "AIR CONDITIONING CUT CONTROL : System Description" System Description.