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At present, biodiesel fuels using natural-origin materials are expanding in share, and there are many different kinds. Biodiesel fuel generates organic acid when it deteriorates, so care is needed when evaluating the influence of the fuel on automotive fuel-line materials. A model biodiesel fuel was designed taking into account deterioration of the fuel and mixing of impurities into it. Durability of automotive fuel-line rubber and plastic materials were evaluated by using the model fuel. From the evaluation results, it was found that fluoroelastomer (hereafter referred to as FKM) and polyacetal resin (hereafter referred to as POM) deteriorate depending on specific fuel properties and deterioration state. In this paper, we report evaluating results of biodiesel fuels on the automotive fuel-line rubber and plastic materials, and the importance of biodiesel fuel property management.

In a previous study by the authors, austenite (γ phase) formed on the topmost of pulleys after long term operation of continuously variable transmission (CVT) [1]. In general, martensite arising from heat treatment forms on the surface of pulleys and gears. Therefore, the sliding surface has a body-centered cubic (BCC) metal structure, and transformation into and existence of austenite (γ phase) is difficult unless there is a thermal history exceeding the eutectoid point. For the verification of that possibility, it was crucial to obtain temperature variation on the sliding surface. The major problem for such measurements was rotation of parts inside an operating CVT. In this study, uniquely developed measurement system enabled non-contact temperature measurement near the contact portion. Results were substituted to heat conduction equation to predict the temperature at the exact contact portion.

Attempts were made to measure knocking phenomenon by an optical method, which is free from influences of mechanical noises and is allowing an easy installation to an engine. Using a newly developed high durability optical probe, the light intensity of hydroxyl radical component, which is diffracted from the emitted light from combustion, was measured. The intensity of this emission component was measured at each crank angle and the maximum intensity in a cycle was identified. After that, the angular range in which the measured intensity exceeded 85% of this maximum intensity was defined as “CA85”. When a knocking was purposely induced by changing the conditions of the engine operation, there appeared the engine cycles that included CA85 less than a crank angle of 4 degrees. The frequency of occurrence of CA85 equal to or less than 4 degrees within a predetermined number of engine cycles, which can be interpreted as a knocking occurrence ratio, was denoted as “CA85-4”.

1 A new surface modification heat treatment technology called Wonder Process Craft which is different from plating and coating, was applied to the skirt section, which is the sliding surface of the piston in an internal combustion engine. This was intended to improve fuel economy and mechanical characteristics by reducing sliding resistance. In the application of solid lubrication, this treatment does not require the usage of binder, which was necessary for conventional coating, leading to the highest level achievable for the low sliding resistance effect inherent of solid lubrication. Since this treatment does not involve any change in significant dimensions, shapes, surface roughness, and so on, applying this treatment is easy. The persistence of the effect, productivity and recyclability of waste and emissions during treatment were also taken into account.

A new piston secondary motion analysis has been developed that accurately predicts piston strength and the slap noise that occurs when the engine is running. For this secondary motion analysis, flexible bodies are used for the models of the piston, cylinder and cylinder head. This makes it possible to quantify the deformations and secondary motion occurring in each area of the engine. The method is a coupled analysis of the structure analysis and the multi body dynamics analysis. The accuracy of the results obtained in the new analysis method was verified by comparing them to measurement data of piston skirt stress and piston secondary motion taken during firing. To measure piston skirt stress, a newly developed battery-powered telemetric measurement system was used. The calculation results were close to the measurement results both for stress and for secondary motion from low to high engine speed.

When using aluminum for vehicle body parts to reduce weight, the high pressure die casting (HPDC) is widely applied due to its adaptability to thin-wall products, near-net-shape castability, and short casting cycle time. Since a hollow construction is advantageous to increase stiffness of body parts, there has been a need of development of techniques for casting of hollow parts by HPDC. So far, hollow casting by HPDC has been realized for small parts using sand cores. When applying that method to large parts, however, it is necessary to increase filling speed. When the filling speed is increased, the core tends to break. In this project, we have developed a method to estimate changes of pressure distribution when filling molten metal by the casting simulation in order to analyze damages to the core. Through the analysis, we discovered occurrence of impulsive pressure waves.

A new type of lean NOx catalyst has been developed with improved thermal resistance. This lean NOx catalyst contains precious metals and NO2 adsorbents. The precious metals are used mainly for the oxidation reaction of NO, and the NO2 adsorbents are for the adsorption removal of generated NO2. The thermal resistance of the catalyst was raised by paying attention to the following points. 1) Improvement of thermal resistance for the NO oxidation activity by addition of a different precious metal element. 2) Prevention of thermal degradation of the NO2 adsorbent by addition of a new metal oxide. For item 1, Pd was added to the catalyst which had already included Pt. By having Pd coexist with Pt, the precious metal dispersion was kept high even after heat treatment, so the NO oxidizing ability was improved. For item 2, thermal degradation of NO2 adsorbent was prevented by addition of the new metal oxide (B) to the adsorbent.

When the alkali metal-supported catalyst was treated at 830°C, the NOx conversion decreased because the alkali metals in the catalyst layer gradually moved to the cordierite honeycomb layer and reacted with the cordierite elements. This phenomena decreased to be added the basic metal oxide (α) in the catalyst layer. The improved catalyst with α 2 showed higher performance than the conventional catalyst in the model gas test. Moreover, the emission values of NOx, HC, and CO were 50% or less than Japanese domestic regulation values even after 830°C×60h heat treatment in a vehicle test.

In this research, a new wire material made using surface-reforming heat treatment was developed in order to enhance the corrosion fatigue resistance of suspension springs. The aim of surface reforming is to improve hydrogen embrittlement characteristics through grain refinement and to improve crack propagation resistance by partial softening of hardness. The grain refinement method used an α'→γ reversed transformation by rapid short-term heating in repeated induction heating and quenching (R-IHQ) to refine the crystal grain size of SAE 9254 steel spring wire to 4 μm or less. In order to simultaneously improve the fatigue crack propagation characteristics, the possibility of reducing the hardness immediately below the spring surface layer was also examined. By applying contour hardening in the second IHQ cycle, a heat affected zone (HAZ) is obtained immediately below the surface.

In the automobile industries, weight reduction has been investigated to improve fuel efficiency together with reduction of CO2 emission. In such circumstance, it becomes necessity to make an electric power steering (EPS) more compact and lightweight. In this study, we aimed to have a smaller and lighter EPS gear size by focusing on an impact load caused at steering end. In order to increase the shock absorption energy without increase of stopper bush size, we propose new theory of impact energy absorption by not only spring function but also friction, and a new stopper bush was designed on the basis of the theory. The profile of the new stopper bush is cylinder form with wedge-shaped grooves, and when the new stopper bush is compressed by the end of rack and the gear housing at steering end, it enables to expand the external diameter and produce friction. In this study, we considered the durability in the proposed profile.

The two liter DOHC-VTEC engine developed for the Honda S2000 produces 179kW (240HP, which is 120HP per liter). It is the highest output power among all naturally aspirated two liter engines ever mass-produced. It also achieves an exhaust emission level within National LEV standards. The new engine utilizes a redesigned VTEC cylinder head, in which MIM (metal injection molding) rocker arms are used. The new cylinder block with a ladder frame structure for its lower part, a newly developed camshaft drive chain and gear system and a metal honeycomb catalyst with an air pump start-up system are also utilized.

This paper describes the development of non-contacting detection type torque sensor that realizes a small lost motion with light weight and low cost. Pedal-equipped electric vehicles are becoming popular in recent years. In those vehicles, torque sensors are usually necessary for measuring the pedaling force to determine the motor torque. We applied an integrated sensing structure and a non-contacting scheme utilizing inverse-magnetostrictive material to minimize the lost motions. As for the sensing material, nickel-iron alloy plating was used to obtain a wide dynamic range. In the tests using the actual structure, the output linearity deterioration occurred because of the strain distribution dispersion produced by the ratchet drive structure. Therefore, the effect of this strain distribution was examined. The inverse-magnetostrictive sensing material of nickel-iron alloy plating has an extremum on its output curve.

Nd₂Fe₁₄B sintered magnets are used in the drive motors of hybrid, electric and other vehicles. A magnet in which rare earth content is reduced by means of a localized diffusion method has been developed in order to reduce the volume of dysprosium. The distribution of the demagnetization fields in a motor is not uniform, so the necessary coercivity distribution for the magnets was quantified using Computer-Aided Engineering (CAE). Then material specifications of the localized dysprosium diffusion satisfied with this coercivity distribution was determined, and optimal manufacturing conditions including the position of dysprosium diffusion were set. The coercivity distribution in every position of the magnet using localized diffusion method was inspected. As a result, the magnet was satisfied with coercivity distribution demanded by CAE.

This research is aimed at development of the catalyst for gasoline automobiles which uses only palladium (Pd) among platinum group metals (PGMs). And the conformity emission category aimed at LEV III-SULEV30. For evaluation, the improvement effect was verified for 2013 model year (MY) ACCORD (LEV II-SULEV) as the reference. As compared with Pd-rhodium (Rh) catalyst, a Pd-only catalyst had the low purification performance of nitrogen oxides (NOx), and there was a problem in the drop in dispersion of Pd by sintering, and phosphorus (P) poisoning.

Conventional HEV motors use neodymium magnets with added heavy rare earths, to realize high output and size reduction. However, deposits of heavy rare earths such as Dysprosium (Dy) and Terbium (Tb) are unevenly distributed, so it is important to reduce the amount used, because of supply issue and material cost. In this paper, the application of a heavy rare earth-free magnet is considered on the new motor for a two-motor hybrid system. Compared to conventional neodymium magnets, heavy rare earth free magnets tend to have low coercivity. Also, heavy rare earth-free magnet have low thermal durability, so it is not easy to apply them to motors for a two-motor hybrid system, which requires high output and small size. The motor requires twice as much torque and six times output than one-motor hybrid system. Increase demagnetization resistance and magnet cooling performance is studied by development of the new motor.

HONDA completed research and development of the Metal V-Belt for CVTs in-house for the purpose of reducing the minimum pitch radius. The newly developed belt is essential to the compactness of a CVT and increases the speed ratio range. Increase of ring stress caused by reducing the minimum pitch radius is treated by improvement of element shape, optimizing clearance between elements and between element and ring and improving materials.(1) In this paper, the optimization of clearance between elements, heat treatment of elements and optimization of ring material are described in detail. Optimum total clearance between elements for a virgin belt is defined by test results during operation using a specially engraved gap sensor and a telemeter system. Tolerance and conditions of heat treatment for elements are optimized concerning fatigue strength of the element nose.

Using sand cores, the weld-able, hollow die-cast parts have been developed. For casting, the transition flow filling method is applied to reduce gas containment and to minimize damages to the core. In designing the products, the newly developed core stress prediction system by melt pressure distribution and the newly developed in-product gas containment prediction system have been applied. The hollow die-cast frame made by the new method attains a 30% increase in rigidity and 1kg reduction of weight.

The technology for a new, high-strength piston material has been developed by using high pressure die casting (HPDC) method, which had a rapid rate of solidification. This method allowed the amount of Ni added to be increased to 5.5 mass%, raising the fatigue strength of the new material at temperatures of 523 K or higher by a factor of 1.5 over that of a conventional material made by gravity die casting (GDC). In addition, application of vacuum to the die cavity and using additional pressure enabled quality exceeding that of conventional GDC pistons. Pistons made from the newly developed material decreased engine friction by 4.4% and increased fuel efficiency by 2.2% in engine bench testing.

SUS301-EH is widely used as a material for exhaust system gaskets, however, at temperatures in excess of 400°C, it can not be used as gas-seal ability of the material declines due to its reduced hardness. The following methods were found to be effective in controlling the softening of stainless steel at high temperatures: (1) The addition of a nitrogen component; (2) Stabilization of the austenite structure; (3) The addition of a molybdenum component. The addition of 0.5% nitrogen to austenitic stainless steel containing molybdenum has enabled the speed of softening at high temperatures to be significantly reduced, due to strain aging by solid nitrogen below 600°C and the combined effects of precipitation hardening and control of growth of recrystallized grains through the precipitation of fine Cr2N on the dislocations and the grain boundary above 600°C.

The environmental performance of automobiles and automobile engines in particular is the foremost issue in the automotive industry today. In addition, engine durability performance is an essential aspect of engine oil performance. Four-cycle motorcycle engine oils formulated with dialkyl phosphate, a sulfur-free additive developed as an alternative to ZDDP, provide excellent environmental and durability performance in terms of longer drain intervals, cleanliness and low corrosion properties.