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It is considered that door mirror drag is composed of not only profile drag but also interference drag that is generated by the mixing of airflow streamlines between door mirrors and vehicle body. However, the generation mechanism of interference drag remained unexplained, so elucidating mechanism for countermeasures reducing drag have been needed. In this study, the prediction formulas for door mirror drag expressed by functions in relation to velocities around the vehicle body were derived and verified by wind tunnel test. The predicted values calculated by formulas were compared with the measured values and an excellent agreement was found. In summary, new prediction formulas made it possible to examine low drag mirror including profile and interference drag.

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.

Incompressible viscous unsteady airflow around three types of automobiles are simulated. A thirdorder upwind-difference scheme is used in these simulations. In all the analyses, computational grids are generated by a multi-block transformation and a transfinite method in each block. The first two types of automobile have almost the same shape in the front half of the body, and the accuracy of predicting the difference in drag coefficient is investigated. In this case, the bodies are simplified. They have flat under-floors and no wheels. These calculated results are compared with experiments using 1/5 scale models. The difference in drag coefficient between the two types agrees well with the experiments, and also the values themselves agree well. In the last case, a car with wheels and an under-floor resembling a production model is studied. Simulated results are compared with experiments using a real production car with closed front opening and without mirrors.