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This paper explains the specific measures taken to develop the body and underfloor of the newly developed Electric Vehicle for the purpose of reducing drag. Additionally, the headlamps and fenders were designed with innovative shapes to reduce wind noise that occurs near the outside mirrors. As a result of utilizing the aerodynamic advantages of an electric vehicle to maximum effect, The newly developed Electric Vehicle achieves a class-leading drag coefficient and interior quietness.

This paper describes a system for measuring unsteady pressure at up to 256 spatial points and at frequencies up to 300 Hz. The system consists of commercially available equipment for measuring steady pressures. It is based on the use of electronically scanned pressure (ESP) sensors, 16 A/D converters, and a personal computer to control the whole system and acquire data. The signal outputs through the tubes connecting the pressure taps and the ESP sensors are compensated, as are the phase delays between the scanned signals and the gain variation. A 1/5 scale model of a sedan was used in this experiment. The passenger car model was placed in a wind tunnel equipped with a moving belt, which was operated at the same speed as the uniform flow in the wind tunnel. Pressure measurements were obtained at 252 points in a plane behind the model perpendicular to the uniform flow. Measurements were made with the belt turned on and off.

Noise reduction of Automotive HVAC systems is a hard task because of the highly complicated and very sensitive turbulent flow in the blower fan unit. First, we identified the location of noise sources by the Sound Intensity (SI) method, then we investigated the flow pattern by the oil-mist method. As a result, two main noise generation mechanisms have been identified. One mechanism is generated by the interaction of the strong steady flow of air in the unit with the fan wheel, and the other is from the turbulent flow between the fan blades. Results: A new fan blade design was developed that had improved control of the turbulent flow, and which configuration caused a noise reduction of 2 dB-A over current blown fan systems.

Flow velocity distributions in the passenger compartment were measured from visualized images of particle flow paths obtained with a full-scale model. The flow paths were visualized using an approach that combined a particle tracing method with a pulse-laser light technique. Air was used as the fluid medium with the full-scale passenger compartment model and water was used as the fluid medium with a one-fourth scale model. A comparison of the results obtained with the two models confirmed that there was good agreement between the flow velocity distributions. Using the full-scale model, measurements were also made of the flow velocity distributions when two dummies were placed in the front-seats.

In this work, the flow velocity distribution was determined by measurements of visualized flow, obtained with a one-fourth scale three-dimensional model, and by numerical analysis. The measurements of interior flow were obtained using a method which combined the particle-tracking technique, a basic method conventionally employed for flow visualization, with a pulsed-laser-light-sheet technique. Flow images taken with a video camera were then processed by means of an image processing system. Flow velocity distributions were obtained for two different discharge modes - a dashboard-vent mode in which air was discharged from four vents provided along the top of the dashboard, and a bi-level mode in which vents at the foot position were added to those of the first mode. Three-dimensional numerical analyses using a direct-simulation method were conducted to calculate the interior flow, and a comparison was made with the measured results obtained in the visualization experiment.