Air Conditioning Control System

The fin and plate, brazed aluminium evaporator is installed in the cooling unit behind the passenger's side of the fascia, to absorb heat from the exterior or recirculated inlet air. Low pressure, low temperature refrigerant changes from liquid to vapour in the evaporator, absorbing large quantities of heat as it changes state.

Most of the moisture in the air passing through the evaporator condenses into water, which is drained away from the air inlet casing via a drain tube routed to beneath the vehicle.

Refrigerant Lines To maintain similar flow velocities around the system, the diameter of the refrigerant lines varies to suit the two pressure/temperature regimes. The larger diameters are installed in the low pressure/temperature regime and the smaller diameters are installed in the high pressure/temperature regime. Low and high pressure charging connections are incorporated into the refrigerant lines for system servicing.

Air Conditioning Control System

In conjunction with the Engine Control Module (ECM), the air conditioning control system operates the cooling/ condenser fans and the compressor clutch to control the flow of refrigerant through the system.

The air conditioning control system comprises of a compressor clutch relay, an evaporator temperature sensor, a refrigerant pressure sensor, a cooling fan control module and control switches. These controls, in conjunction with the cooling fans, compressor clutch, blower and heater distribution and blend unit, maintain the required environment inside the vehicle with minimal input from the driver.

When air conditioning is not selected, air is supplied by ram effect or blower operation to the areas selected by the air distribution control. The air mix flap on the heater assembly blend unit controls the temperature of the air being delivered. No cooled air is available. HEATING AND VENTILATION, DESCRIPTION AND OPERATION, Description.

Selecting air conditioning provides the added facility of cooled air available to be mixed with heated air in the blend unit. When required, a fully cold condition can be selected by turning the temperature control selector to the cold position, this automatically closes the path of inlet air through the heater matrix.

Mixtures of cooled, fresh, and hot air can be selected to give the required interior environmental conditions by selection at the control panel.