Air Conditioning
Air Conditioning
The air conditioning (A/C) system is a clutch cycling, fixed orifice tube type.
The A/C compressor is driven by the engine. The A/C compressor primes the gaseous refrigerant out of the suction accumulator and compresses it. The refrigerant heats up and is passed to the condenser core under high pressure.
At this point heat is drawn from the refrigerant by the air being forced past the cooling fins. Because of this heat loss, the refrigerant liquefies and leaves the condenser core.
An evaporator core orifice, which separates the refrigerant at high pressure from that at low pressure, is located between the condenser core and the evaporator core. This evaporator core orifice slows down the flow of the refrigerant from the A/C compressor, so that the pressure builds up in the condenser core.
After passing through the evaporator core orifice the liquid refrigerant expands in the circuit to the evaporator core. In the evaporator core the liquid refrigerant converts back into the gaseous state and this causes heat to be extracted from the air coming into the vehicle. The air therefore cools down and the moisture it contained is given up at the evaporator core. The refrigerant enters the suction accumulator and is primed up again by the A/C compressor.
The system is protected by the pressure transducer. The pressure transducer is used to control over pressure in the high side of the A/C system.
A/C Compressor and Clutch Assembly
NOTE: Internal A/C compressor components are not serviced separately. The A/C scroll compressor is serviced only as an assembly.
The compressor has a variable capacity via an internal valve, which can by-pass volume through the compressor when required. Compressor output varies from 100% to 30% depending on refrigerant demand, the variation being governed by the internal valve within the compressor housing. The compressor has protection in the form of a pressure relief valve and a sensing element for over temperature conditions.
A/C Compressor and Clutch Assembly:
The magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When battery positive voltage is applied to the A/C clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley.
- The magnetic force locks the clutch disc and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate.
- When battery positive voltage is removed from the A/C clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch pulley.
A/C Condenser Core
The A/C condenser core has the following characteristics:
- It is an aluminum fin and tube design heat exchanger located in front of the vehicle radiator.
- It cools compressed refrigerant gas by allowing air to pass over fins and tubes to extract heat and by condensing gas to liquid refrigerant as it is cooled.
A/C Evaporator Core
The A/C evaporator core is mounted within the passenger compartment and is situated with the heater core in a single housing.
Suction/Accumulator
The suction/accumulator is mounted under the right-hand front wheel arch liner.
The suction/accumulator is connected to the low pressure side of the A/C system and is used to make sure only refrigerant gas is passed to the compressor and not liquid.
The suction/accumulator also removes moisture from the refrigerant.
A/C Pressure transducer
The pressure transducer is used to control over pressure in the high side of the A/C system.
Fixed orifice tube
The fixed orifice tube system allows the compressed liquid to expand, by metering the liquid into the low pressure area of the evaporator.
The low pressure being created by the restriction of the fixed orifice tube and the suction of the scroll type compressor.
The liquid begins to change state by transferring from a high pressure liquid into a low pressure gas immediately it leaves the fixed orifice tube.
Service Gauge Port Valves
The service gauge port valves are located on the right-hand side at the rear of the engine bay.
The fitting is an integral part of the refrigerant line or component.
- Special couplings are necessary for both the high side and low side service gauge ports.