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To realize the high performance of the three-way catalyst, this development focused on the heat resistance of the CeO2-ZrO2 solid solution (CZ) that possesses the oxygen storage capacity (OSC). A new concept of the OSC compound with high durability is proposed. We devised a new method of inhibiting the coagulation of the primary CZ particles by placing diffusion barrier layers made of alumina among the primary CZ particles. This material is called “ACZ”. The specific surface area of ACZ was larger than that of the conventional CZ after durability test. The sintering of Pt on the ACZ-added catalyst is inhibited and the crystal size of CZ in the ACZ-added catalyst is smaller than that in the CZ-added catalyst. The OSC and the light off temperature of the ACZ-added catalyst are improved.

The objective of this study is to improve tire hydroplaning performance by examining the arrangement of the tread grooves, based on water flow. It is important to smoothly channel the water through the tread grooves to improve performance. For this purpose, flow around the tire contact area was visualized by particle tracing. The velocity and the direction of flow in front of the contact area became clear as a vector map. This vector map indicated that the direction of the flow depends primarily on the lateral position, i.e., the distance from the tread center. Tread grooves parallel to the flow vector were designed based on this result. The visualization of the improved tire demonstrated that water flowed smoothly along the grooves. In addition, a drum test indicated increased cornering force at high speed.

To clarify the thermal deterioration mechanism of three-way catalysts quantitatively, we investigated the relationship between the catalytic performance and the catalyst characteristics for thermally aged Pt/Rh catalysts. 1. Experimentally, the HC oxidation reaction, which occurs on the surface of Pt/Rh particles on catalysts, is approximated by a first-order reaction of HC concentration with a constant activation energy. 2. The relationship between the Pt mean diameter D and the HC 50% conversion temperature T50 is described by the following equation; where E and kB are the activation energy of the reaction and the Boltzman constant, respectively. 3. The sintering rate of Pt particles on the three-way catalysts was found to depend on the aging temperature(T) of catalyst and the concentration of oxygen in the gas phase([O2]).

It is said that a four-wheel drive (4WD) system which can control the distribution of driving torque to the front and rear axles will result in remarkably improved tractive and cornering performance. However, because of the difficulty in obtaining accurate vehicle speed information and in identifying the influence of engine brake torque on performance on slippery roads, it has been difficult to apply an anti-lock braking system (ABS) to vehicles equipped with such a 4WD system. This paper discusses a solution to this problem achieved through the utilization of a vehicle dynamic simulation model and a new integrated anti-lock and traction distribution control method. The existence of an optimum front/rear torque split which makes it possible to estimate vehicle speed accurately and to obtain the best level of ABS control performance is shown.

Microprocessor-based control technology has found widespread application in automotive engineering. Nissan has been studying the effective application of a microprocessor to an automatic transmission system. A new microprocessor controlled automatic transmission has been introduced to meet the demands for better fuel economy and driveability. The microprocessor controls the optimum operation of the lockup clutch in all four speeds which provides improved fuel economy and driving performance. Engagement and disengagement of the clutch are carried out precisely without degrading shift quality. The other controls for down-shifting while coasting and automatic selection of the shift schedule also improve driveability. These controls are the first of their kind to be applied in the world.