Air Conditioning
AIR CONDITIONING (OPTIONAL)The present vehicle can be optionally provided with an air conditioning.
This Section covers the description, charge of refrigerant, etc; of the air conditioning.
MAJOR COMPONENTS AND REFRIGERANT FLOW OF AIR CONDITIONING SYSTEM
FUNCTION OF EACH COMPONENT
COMPRESSOR
Compresses the gas vaporized in the evaporator.
Thus compressed gas is sent to the condenser where it is changed into liquid refrigerant whose heat of vaporization can be reused.
Compressors used for the air conditioning of vehicle include reciprocating-,swash plate-,and wobble plate-types. This model employs the swash plate-type less in vibration and excellent in durability.
MAGNETIC CLUTCH
A device used,with the engine running,for operating the compressor only when the air conditioning is needed and stopping it otherwise. Employs a powerful electromagnet.
CONDENSER
Serves to change the compressor-compressed,high temperature/high pressure-obtained refrigerant into liquid refrigerant by forcibly taking heat therefrom.Constructionally the same as the radiator. Installed at the frontmost of the vehicle for increased heat radiation,and cooled compulsorily by the cooling fan.
RECEIVER/DRYER
The receiver/dryer has the three roles as described below:
A) The receiver section serves as a temporary storage container of condenser-liquefied refrigerant so that it is possible to supply the evaporator with the condenser-liquefied refrigerant just conforming to the demand of the cooling load.
B) The dryer section serves to remove the dirt and water mixed in the cycling refrigerant by means of the filter and desiccant sealed therein.
C) The sight glass, installed atop the receiver,serves to look at thereby the flowing state of the refrigerant.
DUAL PRESSURE SWITCH
A control switch to stop further rotation of the compressor by turning OFF the electric circuits of the magnetic clutch and condenser cooling fan when the cycling refrigerant is abnormally dropped or risen in pressure.
EXPANSION VALVE
A device to eject the receiver/dryer-passed liquid refrigerant from fine holes for sudden expansion to produce atomized refrigerant of low temperature and low pressure.
EVAPORATOR
Passes therethrough the cold atomized refrigerant to lower the ambient temperature.
The refrigerant,now changed into hot gas,is sent to the compressor.
Functionally,the evaporator acts just inversely to the condenser.
(The refrigerant takes a state of liquid when entering the evaporator and a state of gas when leaving therefrom.)
FUNCTION OF EACH CONTROL COMPONENT
RELAY (condenser fan/magnet clutch)
A relay to operate the condenser fan motor and magnetic clutch.
The motor continues operation as long as the air conditioner (compressor) is under operation.
EVAPORATOR THERMISTER
When the evaporative temperature of a refrigerant drops toss to 1 °C (34°F) or below, the evaporator fins get stuck with frost or ice,reducing the airflow,lowering the cooling capacity.
The thermister is a sensor which is used to prevent this frosting or icing.
The termister installed to evaporator converts the evaporative temperature into a resistance value and send it to A/C amplifier.
COOLANT (WATER) TEMP SWITCH
A switch to stop compressor operation when the coolant temperature exceeds 110°C (230°F).
DUAL PRESSURE SWITCH
A control switch to stop the compressor operation when the cycling refrigerant is dropped in pressure due to its leakage, lack of refrigerant or has reached too high a level.
The switch is installed in the high pressure line behind the receiver dryer.
A/C AMPLIFIER
A/C amplifier is installed to the lower evaporator case.
It controls operation of the compressor magnet clutch and condenser fan motor according to the signals from the sensors which detect the state of the engine and driving conditions.Main system control functions are as follows (at A/C switch ON).
- Idle speed control (idle-up).
- Magnet clutch delay control:0.8 second delay after solenoid vacuum valve on or outputting A/C ON signal to ECM.
- A/C ON-OFF control:
High refrigerant pressure:
above 3140 kPa
(32 kg/cm2,455 psi) ...... OFF
below 2550 kPa
(26 kg/cm2,370 psi) ...... ON
Low refrigerant pressure:
below 196 kPa
(2.0 kg/cm2,28.4psi) ..... OFF
above 226 kPa
(2.3 kg/cm2,32.7 psi) .... ON
Engine coolant temperature:
above 110°C (230°F) ......... OFF
below 103°C (217°F) ......... ON
While engine cranking with
starter on ........................ OFF
Evaporative temperature:
below 1°C (34°F) .............. OFF
above 2°C (35°F) .............. ON
While accelerating rapidly:
(when throttle opened 90%
within 10 seconds) ........... OFF