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Currently, two consolidated aftertreatment technologies are available for the reduction of NOx emissions from diesel engines: Urea SCR (Selective Catalytic Reduction) systems and LNT (Lean NOx Trap) systems. Urea SCR technology, which has been widely used for many years at stationary sources, is becoming nowadays an attractive alternative also for light-duty diesel applications. However, SCR systems are much more effective in NOx reduction efficiency at high load operating conditions than light load condition, characterized by lower exhaust gas temperatures.

A new nitriding technology and material technology have been developed to increase the strength of microalloyed gears. The developed nitriding technology makes it possible to freely select the phase composition of the nitride compound layer by controlling the treatment atmosphere. The treatment environment is controlled to exclude sources of supply of [C], and H2 is applied as the carrier gas. This has made it possible to control the forward reaction that decomposes NH3, helping to enable the stable precipitation of γ′-phase, which offers excellent peeling resistance. A material optimized for the new nitriding technology was also developed. The new material is a low-carbon alloy steel that makes it possible to minimize the difference in hardness between the compound layer and the substrate directly below it, and is resistant to decline in internal hardness due to aging precipitation in the temperature range used in the nitriding treatment.

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.

A new motor has been developed that combines the goals of greater compactness, increased power and a quiet drive. This motor is an interior permanent magnet synchronous motor (IPM motor) that combines an interior permanent magnet rotor and a stator with concentrated windings. In addition, development of the motor focused on the slot combination, the shape of the magnetic circuits and the control method all designed to reduce motor noise and vibration. An 8-pole rotor, 12-slot stator combination was employed, and a gradually enlarged air gap configuration was used in the magnetic circuits. The gradually enlarged air gap brings the centers of the rotor and the stator out of alignment, changing the curvature, and continually changing the amount of air gap as the rotor rotates. The use of the gradually enlarged air gap brings torque degradation to a minimum, and significantly reduces torque fluctuation and iron loss of rotor and stator.

In the early stages of aerodynamic development of commercial vehicles, the aerodynamic concept is balanced with the design concept using CFD. Since this development determines the aerodynamic potential of the vehicle, CFD with high accuracy is needed. To improve its accuracy, spatial resolution of CFD should be based on flow phenomenon. For this purpose, to compare aerodynamic force, pressure profile and velocity vector map derived from CFD with experimental data is important, but there are some difficulties to obtain pressure profile and velocity vector map for actual vehicles. At the point of pressure measurement for vehicles, installation of pressure taps to the surface of vehicle, i.e., fuel tank and battery, is a problem. A new measurement method developed in this study enables measurement of surface pressure of any desired points. Also, the flexibility of its shape and measuring point makes the installation a lot easier than the conventional pressure measurement method.

When a vehicle is cruising, unpleasant noise in the 4 to 5 KHz high-frequency band can be heard at the center of all seats in the vehicle cabin. In order to specify the source of this noise, the correlation between the noise and airborne noise from the outer surface of the transmission was determined, and transfer path analysis was conducted for the interior of the transmission. The results indicated that the source of the noise was the 0th-order breathing mode specific to the drive motor. To make it possible to predict this at the desk, a vibrational analysis method was proposed for drive motors made up of laminated electrical steel sheets and segment-type coils. Material properties data for the electrical steel sheets and coils was employed in the drive motor vibrational analysis model without change. The shapes of the laminated electrical steel sheets and coils were also accurately modeled.

The performance of Gasoline Direct Injection (GDI) engines is governed by multiple physical processes such as the internal nozzle flow and the mixing of the liquid stream with the gaseous ambient environment. A detailed knowledge of these processes even for complex injectors is very important for improving the design and performance of combustion engines all the way to pollutant formation and emissions. However, many processes are still not completely understood, which is partly caused by their restricted experimental accessibility. Thus, high-fidelity simulations can be helpful to obtain further understanding of GDI injectors. In this work, advanced simulation and experimental methods are combined in order to study the spray characteristics of two different 3-hole GDI injectors.

The field of diesel combustion research is producing numerous reports on studies of premixed combustion, which promises simultaneous reduction of both NOx and soot, in order to meet increasingly stringent regulations on harmful emissions from automobiles. However, although premixed combustion can simultaneously reduce both NOx and soot, certain issues have been pointed out, including the fact that it emits greater quantities of unburned HC and CO gases and the fact that it limits the operating range. Furthermore, this combustion method sets the ignition delay longer with the aim of promoting the mixing of fuel and air. This raises issues with the product due to the combustion instability and sensitivity to the uneven fuel properties that are found on the market, the capability of the engine response under transient conditions, the deterioration in combustion noise, and so on.

Recently, the use of ethanol blended fuel is growing worldwide. Therefore, there is increasing needs for addressing issues relating to ethanol blended fuel use in gasoline engine fuel supply systems. In this paper, we focused on one of such issues, which is the reduced life of a multi-layered fuel filter used at inlet side of a fuel pump when it is used with ethanol blended fuel. In this study, we clarified that ethanol blended fuel tends to disperse dust particles contained in fuel to a greater extent than gasoline, and that it has a mechanism to accelerate clogging by concentrating the clogging only on the finest layer of the multi-layered filter. Also, in the process of clarifying this principle, we confirmed that dust particles dispersed by ethanol are coagulated when passing through the filter layers.

Honda diesel engine vehicles that go on the market in 2018 will be equipped with a newly developed silver (Ag)-type catalyzed diesel particulate filter (cDPF). Ag has high particulate matter (PM) oxidation performance, but conventional catalyst-carrying methods cause weak contact property between PM and Ag; therefore, the newly Ag-type cDPF was developed on the concept of enhancing the property of contact between PM and the catalyst to realize contact property enhancement at the macro, meso, and nano scales. As a result, the newly developed catalyst showed an enhancement of T90 performance by a factor of approximately 2 relative to the conventional Ag-type catalyst in fresh condition. Durability in the environment of an automobile in use was examined through hydrothermal aging, lean-rich (L/R) aging, sulfur (S) poisoning, and ash deposition. The results have confirmed that hydrothermal aging is the greatest factor in deterioration.

Power generation systems employed in small gas engine cogeneration were examined to compare losses in the converter, which converts three-phase alternator power to direct current (DC) voltage, and losses in the inverter, which converts power to high-quality alternating current (AC) voltage that can be connected into electric utility power lines. It is a characteristic of alternators that their efficiency and output voltage decline in the heavy load range. It was found, therefore, that step-down methods using thyristors operate in a low-efficiency range in order to provide a satisfactory supply of the targeted DC output voltage. Use of switching regulator methods, on the other hand, can generate the target voltage by regulating a switching device after first storing the alternator output in a choke coil. It was found, therefore, that these use the high-efficiency range of the alternator. The converter was found to have a resulting loss decrease of 19.4 W.

In an attempt to decrease the amount of CO2 emitted by engines and yet improve engine output power, various approaches to the development of variable valve-lift mechanisms and the application of direct fuel injection and supercharger mechanisms are rapidly gaining popularity. In the case of the swing motion which takes place in variable valve-lift mechanisms, the relative speed between the two components reaches zero at the location where the load is high and the oil film tends to break, thereby leading to wear. Furthermore, the use of a supercharger and a direct injection device generates soot, which promotes further wear. Therefore establishing a reliable method for estimating wear has become a pressing issue. Wear problems caused by the swing motion occur during boundary lubrication, and we have devised a solution for them.

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.

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.

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.

1 Many different bolts are employed in automobiles for different purposes and uses, and their strength generally ranges from 700 N/mm2 to 1200 N/mm2. Automobiles face the issue of making improvements in fuel economy as an environmental measure, and there is consequently a requirement to lighten component parts. The creationof higher-strength bolts is an important factor in achieving lighter weight. Increasing the strength, however, can also bring about an increased incidence of delayed fracture, and the conventional solution used to require the application of special steels such as expensive maraging steel. The present development addressed this issue by focusing on high carbon steel rod, which had been considered less susceptible to delayed fracture, although heading was also considered to be difficult. Heading techniques were therefore devised that made it possible not only to form bolts from this material, but also to provide satisfactory strength.

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.

For reduction of NOx and soot emission with conventional diesel diffusion combustion, the authors focused on enhancement of the rate of injection (hereafter referred to as RoI) to improve air availability, thus enhancing the fuel distribution and atomization. In order to increase opening ramp of the RoI (hereafter referred to as fast injection rate), a hydraulic circuit was improved and nozzle geometries were optimized to make the greatest use of the advantages of the hydraulic circuit. Two different common rail injectors were prepared for this research. One is a mass production-type injector with piezo actuator that achieved the EURO-V exhaust gas emission standards, and the other is a prototype injector equipped with the new hydraulic circuit. The nozzle needle of the prototype injector is directly actuated by high-pressure fuel from common rail to improve the RoI.

In recent years, adhesive bonding is increasingly being applied in the construction of vehicle frames in order to improve body stiffness and crash performance. Regarding crash performance, the behavior of impacted components is affected by the fracture energy value of the adhesive. However, the relationship between the ductility and fracture energy values under mixed-mode loadings has not been sufficiently evaluated. In this paper, the fracture energy of three structural adhesives in a static mixed-mode loading using Double Cantilever Beam (DCB) specimens is presented. To derive the fracture energy values, the Compliance Based Beam Method (CBBM) was used, which allowed for precise determination of fracture energy values. Static mixed-mode loading tests were performed in six configurations of mixed-mode loading, ranging from pure peel mode state to almost pure shear mode state.

Several attempts have been reported in the past decade or so which measured the sizes of particles in lubricant oil in order to monitor sliding conditions (1). Laser light extinction is typically used for the measurement. It would be an ideal if only wear debris particles in lubricant oil could be measured. However, in addition to wear debris, particles such as air bubbles, sludge and foreign contaminants in lubricant oil are also measured. The wear debris particles couldn't have been separated from other particles, and therefore this method couldn't have been applied to measurement devices for detection when maintenance service is required and how the wear state goes on. It is not possible to grasp the abnormal wear in real time by the conventional techniques such as intermittent Ferro graphic analysis. In addition, it is no way to detect which particle size to be measured by the particle counter alone.