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A new index for evaluating load path dispersion is proposed, using a structural load path analysis method based on the concept of U* , which expresses the connection strength between a load point and an arbitrary point within the structure enables the evaluation of the load path dispersion within the structure by statistical means such as histograms and standard deviations. Presenter Tadashi Naito, Honda R&D Co., Ltd.

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 index U* for evaluating load path dispersion is proposed, using a structural load path analysis method based on the concept of U*, which expresses the connection strength between a load point and an arbitrary point within the structure. U* enables the evaluation of the load path dispersion within the structure by statistical means such as histograms and standard deviations. Different loading conditions are applied to a body structure, and the similarity of the U* distributions is evaluated using the direction cosine and U* 2-dimensional correlation diagrams. It is shown as a result that body structures can be macroscopically grasped by using the U* distribution rather than using the stress distribution. In addition, as an example, the U* distribution of torsion loading condition is shown to comprehensively include characteristics of the U* distribution of other loading conditions.

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.

There have been a number of attempts to clarify the relationship between motorcycle specifications and shimmy phenomenon. Some of such efforts are based on equations of motion. The methods used in those efforts are suitable for analyzing motions in a fundamental structure. However, when the degree of freedom is large, it is extremely difficult to deliver an equation of motion. Therefore, a practical method cannot be found generally when applying the methods employing equations of motion. We also conducted the analysis of shimmy using multi-body dynamics simulation. The yielded results were useful only for clarifying the differences in shimmy levels among motorcycles. However, they were not helpful to understand the relationships between specifications and shimmy phenomenon.

Currently, there is a growing demand for application of plastic coverings for motorcycles in the market. Accordingly, decorative features for plastic coverings are increasingly important to enhance the attractiveness of exterior designs of those motorcycles. Under these circumstances, the magnetically formed decorative painting had been adopted to a mass-production model sold in Thailand in 2008. Magnetically formed decorative painting is a method in which the design patterns are formed by painting a material that contains flakes movable along with magnetic fields, while applying magnetic sheets in the ornamenting design shapes underneath the part being painted. It offers a three-dimensional appearance even though its surface has no protrusions or indentations. The degree of three-dimensionality on the paint surface appearance was defined as “plasticity” [1] (a term used in pictorial arts).

In brake squeal analyses using FE models, minimizing the discrepancies in vibration characteristics between the measurement and the simulation is a key issue for improving its reproducibility. The discrepancies are generally adjusted by the shape parameters and/or material properties applied to the model. However, the discrepancy cannot be easily adjusted, especially, for the vibration characteristic of the disc model of a motorcycle. One of the factors that give a large impact on this discrepancy is a thermal history of the disc. That thermal history includes the one experienced in manufacturing process. In this paper, we examine the effects of residual stress on the natural frequency of motorcycle discs. The residual stress on the disc surface was measured by X-ray stress measurement method. It was followed by an eigenvalue analysis. In this analysis, we developed a unique method in which the residual stress was substituted by thermal stress.

Exhaust heat recovery units that use a thermoelectric element generate electricity by creating a temperature difference in the thermoelectric element by heating one side and cooling the other side of the thermoelectric circuit (module). In this case, the general structure does not directly join the thermoelectric module with the heat sink, and instead presses the thermoelectric module against the heat sink using bolts or other means in order to prevent thermoelectric element damage due to the difference in linear expansion between the cooled and heated sides of the thermoelectric module. However, this poses the issues associated with a complex, heavy and expensive structure. Therefore, a new vacuum space structure was devised that houses the thermoelectric module in a vacuum chamber and presses the module against the heat sink using atmospheric pressure.

A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept.

Glass fiber reinforced plastic of polyamide is applied as one of the materials used for the high strength exterior parts of a motorcycle, such as a rear grab rail or a carrier, to which both strength and good exterior appearance are required. However, Glass Fiber reinforced Polypropylene (PPGF), which is relatively inexpensive material, has a property that the contained glass fibers are prone to be exposed at the surface and, therefore, the requirements for good appearance are hardly met by using PPGF. In this study, Heat and Cool molding method (H&C molding) was employed to realize a cost reduction by using PPGF yet without applying painting process, and the established method was applied to mass production while fulfilling the requirements for a good exterior appearance. In H&C molding, the metal molds are heated up by steam and cooled down by water after molding.

Simulation was employed to estimate the fuel economy enhancement from the application of an exhaust heat recovery system using a thermoelectric generator (TEG) in a series hybrid. The properties of the thermoelectric elements were obtained by self-assessment and set as the conditions for estimating the fuel economy. It was concluded that applying exhaust system insulation and forming the appropriate combination of elements with differing temperature properties inside the TEG could yield an enhancement of about 3% in fuel economy. An actual vehicle was also used to verify the calculation elements in the fuel economy simulation, and their reliability was confirmed.

Several processes, such as casting, forging, and pressing, were used in the manufacturing of the Honda NSX's aluminum chassis. For casting, a high grade method which utilizes program control of mold temperature was developed and put into practical use. For optimum forging, a selection of cold and hot processes were investigated and a process to save energy during processing was pursued. As a result, an overall weight reduction of approximately 50% was achieved.

A compact, low-cost fuel pump module has been developed for use in motorcycles with a small-displacement engine. Various considerations are given to make the module as compact as possible. The pump motor, which is one of the major component parts, is down-sized specifically for applications to small-displacement engines. The pressure regulator uses a simple construction consisting only of a ball and a spring without a diaphragm. Especially noteworthy is that with the volume reduced by approximately 40% from the conventional pressure regulator while using the construction that reduces self-excited vibrations caused by fuel pressure pulsations, the pressure regulator contributes significantly to the down-sizing and cost reduction of the module. Furthermore, the down-sized module remarkably reduces the size of fuel pump mount surface, allowing a modification from the flat-surface sealing to the radial sealing.

As a result of recent EPA (U.S. Environmental Protection Agency) gasoline permeation control regulations, the fuel tanks on motorcycles and ATVs (All-Terrain Vehicles) are required to change to lower gasoline permeation performance on 2008 models. Therefore, we determined to use a multilayer plastic fuel tank. There are some molding issues that are peculiar to motorcycle and ATV fuel tanks. First, when the insert is blow molded, there is a reduction in welding strength. Second, peeling of the adhesion occurs on impact in the inserted parts. Third, saddle shapes with large ductility deformation are easy to be punctured during molding. Finally, the appearance of the fuel tank is not acceptable. In order to address the first issue, the welding performance, the drawdown of parison and the melting damage of insert parts were balanced, focusing attention to the temperatures of the parison and the insert.

A hexavalent-chromium-free metal gasket for PWC engines was developed to correspond to the ELV (End of Life Vehicle) directive. In order to enhance the adhesive property, the ion capture to trap the chloride ion, an anti-rust pigment to reform the chemical coating, and an inorganic sealer to stop the passage of chloride ion were added to the adhesive and rubber raw material. A good adhesive property and rubber physical property was obtained through the addition of an anticorrosive pigment. The rubber vulcanization condition in the manufacturing process was reviewed. As a result, without modifying the current compound coating line for mass-production, a gasket with a blistering resistance more than hexavalent chromium conversion coating equivalence and coating adhesion was developed when using salt water for engine cooling.

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.

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.

In Japan, rear-end collisions occur at higher frequency than many other kinds of traffic accident. The causes of rear-end collisions were therefore investigated. Accident statistics was used to conduct a statistical traffic accident analysis and a questionnaire survey was used to conduct a detailed traffic accident analysis. Simulation was then used to perform an accident analysis on the basis of those studies. The results suggested that many of these accidents were caused by momentary inattention during daily driving. Research was therefore carried out to determine what kind of collision avoidance assist system would be effective for use at such times. Tests were carried out to measure the obstacle avoidance characteristics of drivers using actual cars, and control timing parameters were established. In this process, the warning timing was set so that it would not lose its impact as a warning and also so that it would not interfere with the driver.

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.