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This study focuses on fluctuations in the aerodynamic load acting on a hatchback car model under steady-state conditions, which can lead to degeneration of vehicle motion performance due to excitation of vehicle vibrations. Large eddy simulations were first conducted on a vehicle model based on a production hatchback car with and without additional aerodynamic devices that had received good subjective assessments by drivers. The numerical results showed that the magnitudes of the lateral load fluctuations were larger without the devices at Strouhal numbers less than approximately 0.1, where surface pressure fluctuations indicated a negative correlation between the two sides of the rear end, which could give rise to yawing and rolling vibrations. Based on the numerical results, wind-tunnel tests were performed with a 28%-scale hatchback car model.

In order to enhance the catalytic performance of the NOx Storage-Reduction Catalyst (NSR Catalyst), the sulfur tolerance of the NSR catalyst was improved by developing new support and NOx storage materials. The support material was developed by nano-particle mixing of ZrO2-TiO2 and Al2O3 in order to increase the Al2O3-TiO2 interface and to prevent the ZrO2-TiO2 phase from sintering. A Ba-Ti oxide composite material was also developed as a new NOx storage material containing highly dispersed Ba. It was confirmed that the sulfur tolerance and activity of the developed NSR catalyst are superior to that of the conventional one.

Recently, the demand of shortening the period of development of Mold and Die and the demand of reducing costs are increasing more and more with the shortening of the life cycle of products. In such a situation, Production workplaces for Molds and Dies need development of the environment that more efficiently produces a product with higher added value. Therefore, development of a high performance machine tool and automation of manufacturing by using computer support are more important. However, the determination of the machining process still depends on the experience of the workers and the past actual results. In this work, support of the computer is not fully developed. In this research, we develop process-planning systems for the machining of Molds and Dies (Mill-Plan) as one of the technologies, which solves such a problem. This report reports the result applied to the composition of this system, and some examples.

We studied the adoption of plastics derived from plants (bioplastics) such as poly(lactic acid) (PLA) for automotive parts in order to contribute to suppressing the increase in CO, emissions. For this application. major improvements of heat and impact resistance are needed. As a method to improve heat resistance, we developed PLA combined with clay of high heat resistance. As a result. we succeeded in synthesizing a PLA-clay nanocomposite using 18(OH)2-Mont. In-mold crystallization of PLA-clay nanocomposite lead to the great suppression of storage modulus decrease at high temperature. which in turn improved the heat resistance of PLA.

In order to improve corrosion resistance and thermal efficiency of the air conditioner evaporator, a coating which provides hydrophilicity was formed over the chromate coating. In addition, there has been greater demand for air with fewer smells. This report describes the cause of “dusty odor” and a method to reduce it. The dusty odor is caused by a little corrosion of the substrate aluminum. Hydrophilic coating film dissolves little by little in condensed water, and substrate aluminum is exposed. A method to prevent the odor was developed by forming a coating giving hydrophilicity and durability to the evaporator surface.

In conventional gasoline engine vehicles, three-way catalysts are used to simultaneously remove HC, CO and NOx from the exhaust gas. The effectiveness of the catalyst to remove these harmful species depends strongly on the oxygen concentration in the exhaust gas. Deterioration of three-way catalyst results in a reduction in its purification activity and OSC (oxygen storage capacity). In this investigation, additive elements were used to enhance the durability and OSC of the catalyst support material. An optimized formulation of a CeO2-ZrO2 and a ZrO2 material was developed to have excellent durability, improved OSC, enhanced interaction between precious metals and support materials, and increase thermal stability. Using these newly developed support materials, catalysts with increased performance was designed.

This paper presents a design method for continuous fiber composites in three-dimensional space with locally varying orientation distribution and their fabrication method. The design method is formulated based on topology optimization by augmented tensor field design variables. The fabrication method is based on Tailored Fiber Placement technology, whereby a CNC embroidery machine prepares the preform. The fiber path is generated from an optimized orientation distribution field. The preform is formed with vacuum-assisted resin transfer molding. The fabricated prototype weighs 120 g, a 70% weight reduction, achieving 3.5× mass-specific stiffness improvement.

Two-layered surface materials composed of a thermoplastic olefin elastomer (TPO) skin and a cross-linked polypropylene (PP)foam are increasingly replacing the conventional PVC skin/PVC foam for interior trims. In the past, recycled material obtained by melt-blending TPO skin and PP foam could not be re-used for TPO skin because of its appearance. A new recycling technology using the reaction biaxial extruder with a reaction agent can decompose the network structure of PP foam. As a result, PP foam is dispersed into TPO uniformly and the recycled material has properties and an appearance similar to virgin TPO. These new properties may allow the application of the recycled material as a surface material.

In order to reduce the energy consumption of the automotive air conditioning system, adsorption heat pump (AHP) system is one of the key technologies. We have been developing compact AHP system utilizing the exhaust heat from the engine coolant system (80-100 °C), which can meet the requirements in the automotive application. However, AHP systems have not been practically used in automotive applications because of its low volumetric power density of the adsorber. The volumetric power density of the adsorber is proportional to sorption rate, packing density and latent heat. In general, the sorption rate is determined by mass transfer resistance in primary particle of an adsorbent and heat and mass transfer resistance in packed bed. In order to improve the volumetric power density of the adsorber, it is necessary to increase the production of the sorption rate and the packing density.

Growing concerns about the depletion of raw materials as vehicle ownership continues to increase is prompting automakers to look for ways of decreasing the use of platinum-group metals (PGMs) in the exhaust systems. This research has developed a new catalyst with strong robustness against fluctuations in the exhaust gas and excellent nitrogen oxide (NOx) conversion performance. One of the key technologies is a new OSC material that has low surface area (SA) and high OSC performance. We enhanced the pyrochlore- ceria/zirconia (CZ) which has a very small SA. In order to enhance the heat resistance and promote the OSC reaction, we selected and optimized the additive element. This material showed high OSC performance especially in the temperature range of 400 degrees or less. Another key technology is washcoat structure that has high gas diffusivity by making connected pore in the washcoat (New pore forming technology).