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Several field problems are anticipated with HFC-134a systems. To be evaluated and clarified are the impacts upon: compressors and systems of chlorine based solvents left in the system from flushing or parts cleaning; mixing in CFC-12; mixing the new lubricants with mineral oil; the effects of certain lubricants and HFC-134a's high hygroscopicity and others. The whole industry should share information and endeavor to maintain the reliability of the new systems from a service engineering standpoint. STARTING IN 1991 the ozone safe HFC-134a refrigerant is expected to replace the conventional CFC-12 in car air conditioning systems and in model years 1994-1995 the major portion of the market will be the new systems. The components/elements and parts used in the new air conditioning systems will embody different designs with new materials which are now considered to be compatible with the new refrigerant-lubricant mixtures.

Certain important factors must be considered when the current refrigerant for automotive air conditioning systems, (A/C), is changed from CFC12 to the ozone safe HFC134a. This paper will focus on lubricant compatibility by presenting a screening process which will cover: a screening table of essential physical properties general information on types of available lubricants tests of chemical stability lubricity compatibility with elastomers methods for testing compressor durability service engineering

A realistic air conditioning system for electric vehicles, (EV), which minimizes the sacrifice of drive range is proposed in this paper. A variable speed semi-hermetic scroll compressor and an automatic louver outlet air temperature control method for a small delivery van are used to attain suitable cooling performance and interior temperature controllability with acceptable noise characteristics. This air conditioning system, (A/C), offers a pre-cooling feature simply by tapping power from commercial electricity outlets before departing for service. The effect of a practical heat influx reduction applied to the vehicle, and of condenser improvement, is evaluated in terms of the electric power consumption and the actual sacrifice of the vehicle's drive range.

In commemoration of the 50th anniversary of the world's automotive air conditioning technology, this historical review is given of the compressor in general, and then of the wobbleplate and scroll types specifically. Sanden has been producing these for the world market since 1971 and 1981, respectively. A new era of the two types of compressors embodying the variable capacity feature is also described.

The discharge valve impact force on the valve retainer and valve plate play a critical role on the NVH characteristics of the wobble plate compressor. Another contributing factor to compressor NVH is in-cylinder bore over-pressure. In order to improve the NVH characteristics, a reduction in the valve impact forces and in-cylinder over-pressure is essential. The focus of this paper will be a new valve plate assembly change utilizing a unique design arrangement. This new design change significantly improved compressor NVH characteristics due to reduction in the the valve impact force as well as in-cylinder over-pressure. A slight reduction in compressor cooling capacity was observed. Research efforts are continuing to overcome this reduction.

Mobile Air Conditioning Compressors with the scroll mechanism design are superior in noise, vibration and harshness (NVH) levels, and in efficiency. For further NVH improvements; for improved comfortability; to enhance the manufacturability to meet the increasing market volumes; and to give better vehicle compatibility in weight reduction and increased durability, the New Type TR Compressor is presented.

The SD-5 Series, five cylinder wobble plate compressors have again been improved to meet the requirements of further size and weight reduction; rapid car interior cool down at the lower speed range; yet maintain an adequate capacity saturation in the high speed range, and lower operating noise. Featured in this paper is an explanation of how the new technology is incorporated. 1) Use of dual TFE piston ring technique, 2) Reduction in the oil circulation ratio in the refrigerant circuit. 3) Optimizing of bore to stroke ratio.

Various physical conditions of the friction surfaces were studied to increase the breakaway torque of the electromagnetic clutch for the automotive air conditioning compressor. The conventional ground steel-ground-steel combination had a disadvantage of low breakaway torque in the running-in period of engagement cycles. This situation was greatly improved by using the combination of the ground armature plate and the machined rotor with zinc plating. In this new technique, the pitch and depth of the machining mark relative to the plating thickness was found to be important. Combinations of machined armature plates and the machined rotors, with or without zinc plating, were also promising, and the mechanism of friction with these surface combinations were analyzed.

Traditionally there have been two types of automotive fixed-displacement air-conditioning compressors on the market. One is the wobble plate (single sided) compressor, and the other is an opposed (double sided) swash plate compressor. Due to the increasing demand for high speed, high performance, quiet compressors, a single sided, swash plate compressor with a fixed displacement was developed. This compressor combines the positive attributes from both types of compressors into a new superior product designed to surpass market requirements.

Performance of the improved serpentine evaporator for automotive air conditioner made with the NOCOLOK ® brazing technique is evaluated and compared with the conventional serpentine, plate fin, and fin-and-tube types, using a proposed method which combines the cooling capacity characteristic and pressure drop from blower to discharge air louvers for a typical duct system. Computer simulation results are also discussed.