A method for controlling transitions between activating and deactivating a vehicle air conditioner compressor is disclosed. In one example, displacement of the air conditioner compressor is adjusted before the air conditioner is coupled to an energy conversion device. The method may provide smooth transitions between different air conditioner compressor control modes.

A cam driven compressor includes a cam coupled to a plurality of cylinder and piston assemblies. Each cylinder and piston assembly comprises a piston located and movable within a respective cylinder. Each cylinder has a cylinder head. The compressor comprises a housing defining a cavity configured to receive a portion of a source gas from one or more of the cylinders in order to maintain a positive gas pressure within the cavity.

A variable displacement swash plate type compressor which smoothly supplies oil contained in a refrigerant inside a crank-case to a drive shaft seal region of a front housing, and thus the frictional heat temperature between the drive shaft and a sealing member can be reduced, leakage of refrigerant and pressure is prevented, and durability can be improved.