HVAC System - Mechanism & Function: Compressor: Function

As the rotor rotates, the volume of each cylinder chamber changes. This creates the compressor's suction, compression and discharge functions as explained in the following:

1. Suction: 

   Low-pressure gaseous refrigerant is forced out from the evaporator by rotation of the compressor. It enters the low-pressure chamber in the rear head through the check valve. The refrigerant is then drawn into the cylinder by rotation of the vane-fitted rotor through the two suction ports provided in the rear side block. Air tightness of the cylinder chambers is maintained by the compressor oil.

   Fig 1: Identifying Compressor Function (Suction)

   Courtesy of SUBARU OF AMERICA, INC.
2. Compression: 

   Further rotation of the rotor after suction makes the volume of each cylinder chamber smaller, thus compression occurs.

   Fig 2: Identifying Compressor Function (Compression)

   Courtesy of SUBARU OF AMERICA, INC.
3. Discharge: 

   When the pressure of refrigerant in the cylinder chamber exceeds a predetermined pressure, the roll valve opens to discharge the refrigerant through a pipe-shaped passage built in the front side block into the high-pressure chamber in the front head. The gaseous refrigerant in the high-pressure chamber is led to a baffle, which separates the compressor oil contained in the refrigerant before it flows into the high-pressure piping.

   Fig 3: Identifying Compressor Function (Discharge)

   Courtesy of SUBARU OF AMERICA, INC.