In axial piston swash plate compressors such as used in motor vehicle air conditioning systems, it is common practice to employ a plurality of double-ended pistons that are driven by the swash plate and develop high pressure refrigerant gas in discharge chambers located in opposite ends of the compressor. The nature of this pumping mechanism is such that high pressure pulsations are generated that can cause noise and vibration problems throughout the air conditioning system. For this reason, it is common practice to either add a muffler to the system or incorporate a muffler arrangement directly in the compressor itself.
For example, in the compressor disclosed in U.S. Pat. No. 4,360,321 assigned to the assignee of this invention, there is a muffler arrangement incorporated directly in the compressor structure. In this particular muffler arrangement, one of the discharge cavities opens directly to a single discharge port leading from the compressor and the other discharge cavity (i.e. the remote one) communicates therewith within the compressor by a pair of attenuation chambers that are interconnected by an attenuation passage and ported to the respective discharge cavities. The volumes of the attenuation chambers are substantially equal and the length of the attenuation passage is substantially longer than the corresponding longitudinal dimension of the attenuation chambers so as to attenuate the discharge pulses from the remote discharge cavity and thereby the overall pulse effect to an acceptable output level totally within the structure of the compressor. While such a muffler arrangement has proven generally satisfactory, it has been found that the gas discharged directly from the one discharge cavity to the compressor outlet can cause undesirable noise and vibration disturbances in the air conditioning system under certain conditions.