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“Adherent odors” emitted from the evaporator in an air-conditioning (A/C) unit are caused by desorption of adherent odorant on the evaporator such as exhaust gas, cigarette odor, interior materials and so on. In an attempt to reduce adherent odors we have developed and initiated production of the ‘Adherent Odor Reductive Coating’. In this paper we investigate the adherent and desorption mechanisms of these odors by componential analyses and odor sensory tests. As the result of the investigation, we find that the odor emission relates to hydrophilic group on the evaporator surface and we design evaporator coating based on the result. This paper also reports the positive effects that our ‘Adherent Odor Reductive Coating’ has in reducing adherent odors.

Among aluminum heat exchangers used for automotive air conditioning, the evaporator is located in the instrument panel. We have developed a new evaporator by: 1) improving the heat transfer performance through use of thinner tubes and fins; 2) establishing technologies for improving corrosion resistance and enabling reduction in wall thickness (development of highly corrosion-resistant material and control of Zn diffusion by shortening brazing time); and 3) improving refrigerant distribution in the tanks. The new evaporator is equivalent to our conventional MS Evaporator (of Multi-Tank Super-Slim Structure)(1) in cooling performance and corrosion resistance, while being significantly thinner (35% reduction) and lighter in weight (40% reduction).

To improve the performance of the air conditioning evaporator, we have Introduced unique refrigerant circuit. This circuit has refrigerant paths for both upstream and downstream air, and these paths are overlapped to provide uniform temperature distribution at the cooling air side. In addition, the fin pitch has also been minimized by establishing a drainage improvement technology. These technologies have made a great contribution to minimizing the core depth of evaporators.

Every year the trucking industry demands lighter weight and lower cost truck components. But it is very difficult to achieve both these targets. This paper describes the example of a suspension system design which was conducted by computer simulation, so called CAE. The computer simulation by FEM was used completely to decide the detailed shape of each part. This paper also introduces a casting method to strengthen the aluminum alloy cast using high pressure during casting. By using this method, products have a precise metallographic structure. As a result, both the development cost and period were reduced by over the half the time required of the current system and lighter and strong parts were created.

This paper is an introduction to the design, development and heat transfer performance of a new drawn-cup plate evaporator for the refrigerant cycle of automotive air conditioning systems. This evaporator is characterized by the tank section at one side alone and U-turn refrigerant path in each tube. This system has reduced dead space and has superior overall heat transfer coefficient. Therefore, we expected that its potential performance would be much higher than any other conventional type. But, while developing it, we encountered some serious structural problems which affected the flow of the refrigerant and heat transfer in the U-turn sections. We isolated the causes of the performance degradation by analizing the refrigerant flow behavior in these sections. With this type of evaporator we finally achieved our target of 15% improved performance compared with the serpentine tube evaporator.