Abstract: The invention is applied to a compressor assembly wherein a coating is applied to the pocket in the piston for sliding engagement with a shoe for reciprocating the piston. The coating is a composite of solid particles of a lubricant, suspended in an adhesive, bonded to the to the aluminum alloy defining the pocket. More specifically, the coating comprises particles of polytetrafluoroethylene (PTFE) suspended in an epoxy resin having a low cross-linking characteristic. The particles of PTFE are sub-micron in size and the ratio of PTFE to epoxy resin is optimally one to one. The thickness of the coating is between two and ten microns and preferably substantially four microns.

Abstract: An accumulator-dehydrator for use in an air conditioning system having a delivery tube that has an unobstructed free end for drawing in vaporized refrigerant and an oil pickup tube for drawing in oil and liquid refrigerant into the hollow delivery tube. The hollow delivery tube includes a venturi portion, which creates the draw necessary to pull the oil and liquid refrigerant into the hollow delivery tube. An equalization hole is also provided to prevent a liquid slug from migrating to the compressor, thereby damaging the compressor.

Abstract: An accumulator-dehydrator for use in an air conditioning system. The accumulator-dehydrator has a hollow delivery tube for delivering vaporized refrigerant and entrained oil to the compressor of the air conditioning system. The delivery tube has an expansion chamber and a separator to eliminate noise within the system.

Abstract: An improved method and apparatus for diagnosing the condition of an automotive HVAC refrigerant compressor based on information contained within the signal produced by a high-side pressure sensor provided for system control purposes. The output signal of the pressure sensor is divided into its DC and AC components, with the DC component being used for system control purposes, and the AC component being used for diagnosing the condition of the compressor. Pulsations of the AC component (which conventionally are removed by filtering for control purposes) correspond to individual piston stroke cycles. The pulsations indicate compressor operation and are counted for purposes of determining the actual compressor speed. Since existing pressure sensor information is utilized to verify compressor operation and to determine compressor speed, the system cost impact due to the diagnostic evaluation is minimal.

Abstract: A baffle for use in an accumulator-dehydrator used in an air conditioning system having at least a first and a second evaporator and a compressor interconnected by refrigerant lines containing refrigerant. The accumulator-dehydrator first and second inlets all connected to the evaporators and an outlet is connected to the compressor through the refrigerant lines. The baffle is mounted inside the accumulator-dehydrator at either the first or second inlet. The baffle has a housing with an opening to allow liquid refrigerant and oil discharged from one of the evaporators to enter the accumulator-dehydrator and prevent liquid refrigerant and oil from within the accumulator-dehydrator from re-entering the inlet.