Compressor HVAC: Description and Operation

The compressor used on this vehicle can be one of two models, depending upon the air conditioning system in the vehicle. All vehicles use the Nippondenso 10S20 compressor. This compressor use an aluminum swash plate, teflon coated pistons and aluminum sleeveless cylinder walls. This compressor includes an integral high pressure relief valve. The compressor is secured low in the right front corner of the engine compartment to a mounting bracket on the cylinder block (2.4L engine), or directly to the cylinder block (3.3L and 3.8L engines) is integral to the compressor. This compressor cannot be repaired. If faulty or damaged, the entire compressor must be replaced. The compressor clutch, pulley, and clutch coil are available for service replacement.

The compressor is driven by the engine through an electric clutch, drive pulley and belt arrangement. The compressor is lubricated by refrigerant oil that is circulated throughout the refrigerant system with the refrigerant. The compressor draws in low-pressure refrigerant vapor from the evaporator through its suction port. It then compresses the refrigerant into a high-pressure, high-temperature refrigerant vapor. The compressor pumps high-pressure refrigerant vapor to the condenser through the compressor discharge port. The mechanical high pressure relief valve is designed to vent refrigerant from the system to protect against damage to the compressor or other system components, caused by condenser air flow restrictions or an overcharge of refrigerant. The valve only vents enough refrigerant to reduce the system pressure, then re-seats itself. The valve opens at a discharge pressure of 3445 to 4135 kPA (500 to 600 psi) or above, and closes when a minimum discharge pressure of 2756 kPa (400 psi) is reached.