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Recently, as for the rod guide bush bearing materials for shock absorbers, lower friction and the improvement of durability are required along with ride quality and longer life of automobile. Usually, lead is contained in bearing materials. However, the addition of the lead in bearing material is being restricted from the earth environmental problem. Bearing materials for shock absorbers are composite material consists of steel backing and covered with polymer surface layer. This basic material structure hasn't been changed till now, though it has been improved by changing its components and compositions based on the customer's requirement. Bearing material with both lower friction and excellent wear resistance has been developed in this study.

Since the modal density of a drum brake system is higher than that of a disc brake system, it is very difficult to identify the cause of brake squeal. The causes of squeal were examined by both complex eigenvalue analysis and experimental analysis. It was confirmed that a complex eigenvalue analysis of a finite element model, a technique so far generally applied to disc brake squeal studies, was effective in analyzing squeal problems of drum brakes.

Road Noise is generated by the change of random displacement input inside the tire contact patch. Since the existing 3 or 6 directional electromagnetic shakers have a flat surface at the tire contact patch, these shakers cannot excite the vehicle in a manner representative of actual on-road road noise input. Therefore, this paper proposes a new experimental method to measure the road noise vehicle transfer function. This method is based on the reciprocity between the tire contact patch and the driver's ear location. The reaction force sensor of the tire contact patch is newly developed for the reciprocal loud speaker excitation at the passenger ear location. In addition, with this equipment, it is possible to extract the dominant structural mode shapes creating high sound pressure in the automotive interior acoustic field. This method is referred to as experimental structure mode participation to the noise of the acoustic field in the vibro-acoustic coupling analysis.

Wheels play an important role in determining the aerodynamic drag of passenger vehicles. This is because the contribution of wheels to aerodynamic drag comes from not only the wheels themselves, but also from the interference effect between wheel wakes and the base wake. As far as the authors are aware, there have been no reports about aerodynamic drag sensitivity to wheel shape factors for different vehicle types and different exterior body shapes. The purpose of this study was to clarify CD sensitivity to wheel shape factors for a sedan and an SUV, including different rear fender shapes. Many different wheel configurations were investigated in terms of the CD, base pressure and flow fields in wind tunnel tests. Multiple regression analyses were conducted to clarify CD sensitivity to each wheel shape factor based on the test data. This study revealed high CD sensitivity factors for both the sedan and SUV.

At Nissan we have developed a new parallel hybrid system for rear-wheel-drive hybrid vehicles. As the main components of the hybrid system, both the motor and the inverter have been developed and are manufactured in house to attain high power density for providing responsive acceleration, a quiet EV drive mode and improved fuel economy. Because the motor is located between the engine and the transmission, it had to be shortened to be within the length allowed for the powertrain. Therefore, new technologies have been developed such as high-density, square-shaped windings and an optimized magnetic circuit specially designed for concentrated winding motors. The inverter is sized to a 12V battery, which it replaces in the engine compartment. Despite its compact size, the inverter must have rather large current capacity to drive a high-power motor. Heat management is critical to the design of a small but high-power inverter.

This paper presents the electrically driven intelligent brake system that has been developed for electric vehicles, which are expected to penetrate markets rapidly amid the ongoing energy paradigm shift. This brake system achieves a cooperative energy regeneration function and high responsiveness while providing braking performance, system reliability and vehicle mounting ease equal to that of conventional brake systems with a vacuum booster. This paper outlines the newly developed brake system and describes how to decide the target brake force which is achieved a regenerative braking capability for recovering energy efficiently without sacrificing braking.