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Titanium alloy for forging and pure titanium material for exhaust systems have been developed. The forging alloy will be applied to production of lightweight motorcycle frames and the pure titanium will be applied to improve engine performance. The materials have been made inexpensive by the use of off-grade sponge that includes many impurities for production of titanium ingot. Stable characteristics have been obtained by controlling oxygen equivalent after setting the volume of tolerable impurities by considering mechanical properties and production engineering. In spite of low-cost, the material provides the same design strength compared to conventional material, and enables parts production with existing equipment. A review of manufacturing and surface treatment processes indicated a reduction in the price of titanium parts produced with this new material.

A computer simulation method for motorcycle rider motion in a collision on a passenger car has been developed. The computer simulation results were in two cases of collision, at 45 degree and 90 degree angles against the side of a passenger car. The simulated results were compared to the test results for validation. The simulation software of explicit finite element method (FEM) has been used, because of its capability for expressing accurate shape and deformation. The mesh size was determined with consideration for simulation accuracy and calculation time, and an FEM model of a motorcycle, an airbag, a dummy, a helmet and a passenger car were built. To shorten the calculation time, a part of the model was regarded as a rigid body and eliminated from the contact areas. As a result, highly accurate dummy posture and head velocity at the time of contact on the ground were simulated in the two cases of collision.

The tires are one of the most important parts of the vehicle chassis, as they significantly influence aspects such as vehicle's directional stability, braking performance, ride comfort, NVH, and fuel consumption. The tires are also a part whose size affects the vehicle's essential specifications such as wheelbase and track width. The size of the tires should therefore be determined in the initial stage of vehicle development, taking into account whether the size allows the vehicle to achieve the targeted overall performance. In estimations of vehicle performance, computer simulation plays more of an important role, and simulated tire models are designed to reproduce the measured tire characteristics of existing tires. But to estimate the chassis performance with various tire sizes or with tires of uncommon sizes, the prevailing modeling approach, “individual models for individual tires,” would not function well because of limited ability to expand tire models to unfamiliar sizes.

When the belt contacts a pulley in a pushing belt-type CVT, vibration is generated by frictional force due to rubbing between the individual elements that are components of the belt, which is said to increase wear and noise. The authors speculated that the source of that vibration is misalignment of the secondary pulley and primary pulley V-surfaces. To verify that phenomenon, a newly developed micro data logger was attached to an element of a mass-produced metal pushing V-belt CVT and the acceleration was measured at rotations equal to those at drive (1000 to 2500 r/m). In addition, the results of calculations using a behavior analysis model showed that changes in pulley misalignment influence element vibration, and that the magnitude of the vibration is correlated to the change in the metal pushing V-belt alignment immediately before the element contacts the pulley.

A model of a timing belt analyzed by FEM (a general non-linear finite element program:ABAQUS) successfully confirmed the mechanism that generates belt cord stress. Analysis revealed a good correlation between the experimental and computed results of stress distribution of the belt cord. Through calculation, it was discovered that belts broke near the tooth root, which is the point of maximum stress of the cord.

In this research, a material model was developed that has orthotropic properties with respect to in-plane damage to support finite element strength analysis of components manufactured from a randomly oriented long-fiber thermoplastic composite. This is a composite material with randomly oriented bundles of carbon fibers that are approximately one inch in length. A macroscopic characteristic of the material is isotropic in in-plane terms, but there are differences in the tension and compression damage properties. In consideration of these characteristics, a material model was developed in which the damage evolution rate is correlated with thermodynamic force and stress triaxiality. In-plane damage was assumed to be isotropic with respect to the elements. In order to validate this material model, the results from simulation and three-point bending tests of closed-hat-section beams were compared and found to present a close correlation.

The practical application of heat recovery using thermoelectrics requires the realization of reasonable cost effectiveness. Therefore, a thermoelectric generator (TEG) structure that can compatibly increase efficiency and reduce cost was investigated with the aim of enhancing cost effectiveness. To increase efficiency, a method of using a vacuum space structure to reduce the TEG size was investigated to enable installation just after the close-coupled catalyzer, which is subject to many space restrictions. It was found that by making it possible to use high temperature exhaust heat, power generation efficiency can be increased to approximately twice that of the typical under floor installation. In addition, coupled simulation of heat transfer and power generation using FEM, 1D cost effectiveness simulations, and bench tests were performed with the aim of reducing cost.

Turbine housings in car engine turbochargers, which use costly stainless steel castings, account for nearly 50% of the parts cost of a turbocharger. They are also the component which controls the competitiveness of the turbocharger, in terms of both function and cost. In this research, focusing on thermal fatigue resistance which is one of the main functions demanded of a turbine housing, achieving reduction in wall thickness while securing sufficient thermal fatigue resistance, it is possible to reduce the amount of material used in the turbine housing and aimed for cost reduction. Therefore, we built a method to quantitatively predict, using 3D FEM, the lifespan from the initiation of thermal fatigue cracking to the formation of a penetrating crack which leads to gas leakage.

The suitability of FM radio receivers for automobiles has conventionally been rated by evaluating reception characteristics for broadcast waves in repeated driving tests in specific test environments. The evaluation of sound quality has relied on the auditory judgment due to difficulties to conduct quantitative evaluations by experiments. Thus the method had issues in terms of the reproducibility and objectivity of the evaluations. To address these issues, a two-stage method generating a virtual radio wave environment on a PC was developed. The research further defined the multipath distortion rate, MDr, as an index for the sound quality evaluation of FM receivers, and the findings concerning the suitability of the evaluation of FM terminals for automobiles were reported at the 2015 SAE World Congress.

There are several all-aluminum cylinder blocks. A typical example is a mono-block cylinder of alusil alloy produced by low pressure die casting. This material's resistance to abrasion and seizure, however, is not satisfactory for motorcycle; in addition, long processing time is another disadvantage. To cope with these problems, the authors developed a light and highly productive all-aluminum cylinder block with a cast-in liner through die casting. The liner is made from powder metallurgy composite (PMC) with 3 to 5 % alumina and 0.5 to 3 % of graphite additives. The PMC reconciles abrasion resistance and machinability. The hardness deterioration of the composite due to the heat at die casting is avoided by using heat-resistant rapidly-solidified powders, made from an aluminum-silecon-iron alloy, for the matrix.

The cooling performance and the heat resistance performance of commercial vehicle are balanced with aerodynamic performance, output power of powertrain, styling, cost and many other parameters. Therefore, it is desired to predict the cooling performance and the heat resistance performance with high accuracy at the early stage of development. Among the three basic forms of heat transfer (conduction, convection and radiation), solving thermal conduction accurately is difficult, because modeling of “correct shape” and setting of coefficient of thermal conductivity for each material need many of time and efforts at the early stage of development. Correct shape means that each part should be attached correctly to generate the solid mesh with high quality. Therefore, it is more efficient and realistic method to predict the air temperature distribution around the rubber/resin part instead of using the surface temperature at the preliminary design stage.

In this research, a simulation method was developed in which it was able to estimate, in the early stage of design, the strains that potentially lead to damages to motorcycle engine parts when tipped over from a stationary state. Splitting a series of phenomena from the start of tilting of motorcycle from the upright position up to the end of collision of engine parts after the contact on the ground to two groups by before and after the contact of engine parts on the ground, we applied the multi body dynamics analysis to the first group, and the elastro-plastic FEM analysis to the latter one. In the computer simulation of collision using the elastro-plastic FEM analysis, we minimized the FEM models from the entire motorcycle models and treated others as a solid model to shorten the computation period. It is also realized that the strains occurring in the engine parts can be simulated by considering only the mass of the parts which are rigidly mounted on the engine.

With a growing demand for high-power diesel engines, a key issue in engine development is to create efficient methods for developing highly durable cylinder heads, without having to repeat trial-and-error testing. Especially, it was difficult to accurately predict the occurrence and origin of cracks on the surfaces of cylinder heads in hot and cold cycle engine operation. This paper describes a thermal fatigue evaluation method developed by analyzing areas around the glow plug hole where cracks often occur during hot and cold cycle engine operation. To reveal the conditions of edges from which cracks were formed under engine durability tests, we used two procedures. One was estimating local temperature of edge areas based on material hardness determination, in order to compensate for the accuracy of the thermal analysis. The other was analyzing the strain amplitudes on the cylinder head surface using computer simulation.

4C3B (4 coat 3 bake) painting system (see Figure 1) which needs a bake process after the primer surfacer paint was very general and common process for the automotive body painting system. In the beginning of the 2000s, 4C2B painting system (Reference 1) was developed which changed the oven after the primer surfacer paint to a pre heat area, so it can reduce the carbon dioxide (Figure 1, and Figure 2). But unfortunately in this 4C2B painting system, the base coat will be painted on the primer surfacer paint wet-on-wet. By that reason, the appearance deterioration will occur often. The authors used a low temperature crosslinking agent “Polycarbodiimide” to a water born primer surfacer paint, to control the viscosity of primer surfacer paint at the pre heat area. Controlling the viscosity is important to avoid the layer mixing of the primer surfacer paint and the base coat which makes appearance deterioration.

Technology has been developed to increase the fatigue strength of powder-forged connecting rods. The fatigue strength of powder-forged materials was increased without adding special alloy components or lowering workability by adjusting the ratios of the conventional main mixed powders (iron, carbon, copper). In addition to solid solution strengthening of the ferrite using copper, reducing porosity, which is a material surface defect, is also an effective method of increasing fatigue strength. Reducing carbon content greatly reduced the occurrence of defects in the forging stage. The results of this research showed that the fatigue strength of high strength powder-forged connecting rods can be increased by 30% or more over that of conventional materials, allowing powder-forged connecting rods to be applied to even higher output and higher load engines than before.

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 multi-use road simulator for reproducing various road loads on motorcycles and buggies has been developed on a test bench by using computer-controlled hydraulic actuators. The device is controlled by a low-priced personal computer and an interface system with custom software. An unique feature is the capability to simulate loads related to such phenomena as the bottoming of suspension and the movement of a telescopic type front fork on the road.

This paper discusses a method of predicting the torque distribution on planet gears originating in manufacturing errors, which is necessary for appropriate strength design of the gears in planetary gear sets. First, an expression of relation between manufacturing errors and the torque on the planet gears in a normal n-planet planetary gear set was derived. As a result, an equation expressing the distribution of torque to the planet gears was obtained. Tests were conducted to verify the validity of the equation in the case of a 4-planet planetary gear set. In order to predict the distribution of torque, it was necessary to estimate the stiffness of the planetary gear set that was the subject of the relational expression. These stiffness values were calculated by numerical analysis using a 3D FEM, into which blueprint values and material property values were input.

For detailed temperature estimates in the engine of a running motorcycle, newly researches were conducted on the method for calculation of temperature distribution using a three-dimensional (3D) thermal conductivity simulation after calculating the total balance of heat generation and heat dissipation of the engine using a one-dimensional (1D) thermal simulation. This project is targeted at air-cooled engines in which the cooling conditions vary significantly depending on the external shapes of the engines and the airflow around them. The heat balance is calculated using the 1D thermal simulation taking into account all the routes and processes for dissipation to the atmosphere of the heat that is generated by the combustion in the engine. The 1D engine cycle simulation is applied to calculate the heat transmission to the engine from the combustion. For the calculation of heat transfer within the engine, the engine components are converted to a one-dimensional model.

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.