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In this study, the optimization calculation of a HVAC configuration upstream the evaporator which governs evaporator transit flow distribution uniformity and the HVAC total pressure drop was tried. The optimization calculation has been mainly applied to structural analysis whose calculation speed is rapid. But we realized a calculation method which can be applied to the design process in fluid analysis by utilizing the response surface method and efficient response surface making method using the mesh morphing technology and validated the result by experimental verification.

CFD has been actively applied for developing automotive air conditioning system in recent years. In addition to automobile interior air conditioning, an automotive air conditioning system has the important function of providing a clear field of view by defogging (or defrosting) the windows. Although many CFD application methods have been reported for estimating windshield defogging pattern, few examples of simulation show accurate result of transient clearing pattern. To predict transient clearing pattern accurately, using a correct model of window glass fogging-clearing is important. As the result of our observation on fogged glass surfaces, fogging was found out to be an aggregation of water drops, so that new dropwise condensation-evaporation model was developed and applied. Transient defogging patterns were simulated with the CFD code including this model, and accuracy was verified on a simplified compartment model and actual automobiles.

In view of the shorter development period for new automobiles, we have developed a computer-aided engineering (CAE) system to aid in commensurately speedy development of automotive air conditioners. This system consists of three tools: one that calculates various design specifications instantaneously, one that enables designers to easily examine air-conditioner shape, and one that converts shape data into calculable model data to enable 3D (three-dimensional) processing. Effective use of these tools cuts air-conditioner development lead time to half that of the conventional process.

With development of high grade and high performance vehicles, there's a growing demand for improvement of thermal comfort in the car. Such comfort is evaluated by the passenger's thermal sensations, such as “hot” or “cold”. For improvement, we need to develop an air conditioning system which can reflect the passenger's sensory feelings as a thermal sensation. In part 1, we described thermal sensation of a passenger in a car depends on not only the skin temperature, but also the rate of change of the skin temperature, and we propose a thermal sensation evaluating equation. For this paper, we used this equation to replace the thermal sensation with the skin temperature, and studied a system which reflects the thermal sensations through on air conditioning control based on the skin temperature. We also verified the advantages of the system under various thermal conditions.

The purpose of this study is to present a new method for controlling a car air conditioning system, in which the air temperature can be controlled to produce any level of occupants' thermal sensation by utilizing car occupants' skin temperatures as a controlling index. In this paper, an equation for a quantitative evaluation of car occupants' thermal sensation, in steady and non-steady states, by face skin temperature and its rate of change was developed and was confirmed by experiments in an environmental chamber to be applicable for all seasons with an accuracy of ±1 in the thermal sensation voting scale we used.