System Diagram

System Description

REFRIGERANT CYCLE

Refrigerant Flow
The refrigerant from the compressor, flows the condenser with liquid tank, the evaporator, and returns to the compressor. The refrigerant evaporation in the evaporator is controlled by an expansion valve.

Freeze Protection

Automatic air conditioner • When intake sensor detects that evaporator surface temperature is 2°C (36°F) or less, A/C auto amp.

requests BCM to turn the compressor OFF.

• BCM requests ECM to turn the compressor to OFF by the signal from A/C auto amp., and ECM makes A/C relay to OFF, and stops the compressor.

Manual air conditioner
• When thermo control amp. detects that evaporator surface temperature becomes 2°C (36°F) or less, BCM requests ECM to turn the compressor OFF, and stops the compressor.

REFRIGERANT SYSTEM PROTECTION

Refrigerant Pressure Sensor • The refrigerant system is protected against excessively high- or low-pressures by the refrigerant pressure sensor, installed at the condenser exit. The refrigerant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the ECM if the system pressure rises above, or falls below the specifications.

• ECM turns the A/C relay to OFF and stops the compressor when the high-pressure side detected by refrigerant pressure sensor is following conditions;

- Approximately 3,120 kPa (31.2 bar, 31.8 kg/cm2, 452 psi) or more (Engine speed is less than 1,500 rpm.) - Approximately 2,740 kPa (27.4 bar, 27.9 kg/cm2, 397 psi) or more (Engine speed is 1,500 rpm or more.)
- Approximately 120 kPa (1.2 bar, 1.2 kg/cm2, 17 psi) or less

Pressure Relief Valve The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.

The release port on the pressure relief valve automatically opens and releases refrigerant into the atmosphere when the pressure of refrigerant in the system increases to an unusual level [more than 3,800 kPa (38 bar, 38.8 kg/cm2, 551 psi)].