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Journal Article

Development of Chemical Process for Recovering High-quality Rare-earth Oxides from HV Motor Magnets

In the automobile industry, interest in the prevention of global warming has always been high. The development of eco cars (HV, EV etc.), aimed at reducing CO2 emissions during operation, has been progressing. In the announcement of its "Toyota Environmental Challenge 2050", Toyota declared its commitment to creating a future in which people, cars, and nature coexist in harmony. In this declaration, Toyota committed to reducing CO2 emissions not only during operation but also over the entire life cycle of vehicles, and to using resources effectively based on a 4 R’s approach (refuse, reduce, reuse, and recycle). Although eco cars decrease CO2 emissions during operation, most of them increase CO2 emissions during manufacturing. For example, the rare-earths (Nd, Dy etc.) used in the magnets of driving motors are extracted through processes that produce a significant amount of CO2 emissions.
Technical Paper

Development of Thermoplastic CFRP for Stack Frame

Weight reduction for a fuel cell vehicle (FCV) is important to contribute a long driving range. One approach to reduce vehicle weight involves using a carbon fiber reinforced plastic (CFRP) which has a high specific strength and stiffness. However, a conventional thermoset CFRP requires a long chemical reaction time and it is not easy to introduce into mass production vehicles. In this study, a new compression-moldable thermoplastic CFRP material for mass production body structural parts was developed and applied to the stack frame of the Toyota Mirai.
Technical Paper

Improvement of Adhesion Properties between Epoxy Resin and Primer and between Primer and Ni Plating in Hybrid Vehicle Power Semiconductor Module under High Temperature Conditions

In this report, adhesion mechanism between epoxy resin and primer and between primer and Ni platting in Hybrid vehicle (HV) was investigated. Adhesion forces are thought to be a combination of mechanical bond forces (such as anchor effect), chemical bond forces and physical bond forces (such as hydrogen bonding and Van der Waals force). Currently there is insufficient understanding of the adhesion mechanism. In particular, the extent to which the three bond forces contribute to adhesion strength. So the adhesion mechanism of polyimide primers was analyzed using a number of different methods, including transmission electron microscope (TEM) and atomic force microscope (AFM) observation, to determine the contributions of the three bonding forces. Molecular simulation was also used to investigate the relationship between adhesion strength and the molecular structure of the primer.
Technical Paper

Development of Gasoline Injector Cleaner for Port Fuel Injection and Direct Injection

Port fuel injection (PFI) injector and direct fuel injection (DI) injector clogging from deposits caused by poor fuel quality, is a concern in emerging countries. Then DI injector deposits are sometimes cleaned by injector cleaners in such situation. However deposit cleaners for PFI injectors have not been developed, because of the lack of research of PFI injector deposits. Through chemical analysis, this study showed them to be water-soluble deposits. Subsequently success was achieved in developing a new gasoline injector cleaner applicable to injector deposits in both types of injectors, through optimization of a surface active agent.
Technical Paper

Two-Dimensional Temperature Measurements in Diesel Piston Bowl Using Phosphor Thermometry

Phosphor thermometry was used during fuel injection in an optical engine with the glass piston of reentrant type. SiO2 coated phosphor particle was used for the gas-phase temperature measurements, which gave much less background signal. The measurements were performed in motored mode, in combustion mode with injection of n-heptane and in non-combustion mode with injection of iso-octane. In the beginning of injection period, the mean temperature of each injection cases was lower than that of the motored case, and temperature of iso-octane injection cases was even lower than that of n-heptane injection cases. This indicates, even if vaporization effect seemed to be the same at both injection cases, the effect of temperature decrease changed due to the chemical reaction effect for the n-heptane cases. Chemical reaction seems to be initiated outside of the fuel liquid spray and the position was moving towards the fuel rich area as the time proceeds.
Technical Paper

Development of Direct and Fast Response Gas Measurement

Due to regulations for even lower levels of pollutants in exhaust gas, development of advanced combustion techniques and increasingly efficient catalysts has become more crucial than ever. One of the essential technologies to achieve this goal is an advanced measurement method, which can detect the characteristics of exhaust gas, such as temperature and chemical compositions, in real-time to clarify their reaction mechanisms. A direct and fast response (1ms) measurement technique was developed based on diode laser absorption spectroscopy and applied to practical engine exhaust measurement to prove the validity of this technology for various applications such as clarification of engine start phenomena and improvement of EGR controls.
Technical Paper

Analysis for Relationship between Vehicle NOx Emission and Roadside NO2 Concentration

NO2 sources of roadside atmosphere at Matsubarabashi monitoring station in Tokyo were investigated analytically. The result showed that contribution of urban background is dominant from November to February and NO oxidation with O3 has large contribution from April to September. NO2 air quality standard will be achieved by reducing vehicle NOx emission to post-new long-term regulation level. The analytical method was verified by using our developed simulation system, which consists of micro traffic flow analyzer and CFD-based, unsteady-state diffusion with chemical reaction solver.
Technical Paper

Characterization of Low Temperature Diesel Combustion with Various Dilution Gases

The effects of intake dilution with various dilution gases including nitrogen, argon, and carbon dioxide on low temperature diesel combustion were investigated in a naturally aspirated DI diesel engine to understand the mechanism of the simultaneous reductions in smoke and NOx with ultra-high EGR. NOx almost completely disappears with the intake oxygen concentration diluted below 16% regardless of the kind of dilution gas. Smoke emissions decrease with increased heat capacity of the charged gas due to promotion of mixture homogeneity with longer ignition delays. Intake dilution with the 36% CO2 + 64% Ar mixture which has a similar specific heat capacity as N2 shows lower smoke emissions than with N2. Chemical kinetics analysis shows that carbon dioxide may help to reduce NOx and soot by lowering the reaction temperature as well as by changing the concentrations of some radicals or/and species related to soot and NOx formation.
Technical Paper

Study of Plastic Plating Using Highly Concentrated Ozonized Water Pretreatment

In order to achieve good adhesive properties, typical decorative plastic plating technology uses a chromic acid process that creates an anchor effect. Due to environmental concerns with hexavalent chromium, there is a need to find alternative processes. Pretreatment using highly concentrated ozonized water was investigated as a novel approach to achieving this goal. In the conventional chromic acid process, strong adhesion between plating membranes is achieved by roughing the ABS (acrylonitrile-butadiene-styrene) resin surface by approximately 1 um. On the other hand, the highly concentrated ozonized water process achieves good adhesion with a smooth resin by changing the resin from ABS to ASA (acrylate-styrene-acrylonitrile). It was discovered that the difference in this strength of adhesion was the difference in resin surface strength (existence of deterioration or otherwise).