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In our preceding report [1], we showed that the thermal conductivity of a heat pipe dramatically improves during high-speed reciprocation. However, this cooling method has rarely been applied to car engine pistons because the thermal conductivity of commercially available heat pipes does not increase easily even if the pipe is subjected to high-speed reciprocation. In consideration of the data from our preceding report, we decided to investigate heat pipe designs for car engine pistons, propose an optimum design, and conduct thermal analysis of the design. As a result, we found that it is possible to transport heat from the central piston head area, where cooling is most needed, to the piston skirt area, suggesting the possibility of efficient cooling.

Car engine piston cooling is an important technology for improving the compression ratio and suppressing the deformation of pistons. It is well known that thermal conductivity improves dramatically through the use of heat pipes in computers and air conditioners. However, the heat pipes in general use have not been used for the cooling of engines because the flow of gas and liquid is disturbed by vibration and the thermal conductivity becomes excessively low. We therefore developed an original heat pipe and conducted an experiment to determine its heat transfer coefficient using a high-speed reciprocation testing apparatus. Although the test was based on a single heat pipe unit, we succeeded in improving the heat transfer coefficient during high-speed reciprocation by a factor of 1.6 compared to the heat transfer coefficient at standstill. This report describes the observed characteristics and the method of verification.

In this study, we developed a simulation method for rough road running condition to reproduce the behaviors of a vehicle body and to precisely estimate the input loads to the frame. We designed the simulation method focusing on a front fork model and a rider model optimized for this type of analysis. In the suspension model development, we conducted detailed measurement of the suspension characteristics on a test bench. Based on the yielded results, the friction force, as well as the spring reaction force and the damping force, was reproduced in the suspension model. The friction of the suspension varies depending on the magnitude of the reaction force associated with bending and this effect was also implemented in the model. Regarding the rider model, the actual behavior of a rider was investigated through the recorded motion video data and used to define the necessary degrees of freedom.

We have developed a bench test method to assess driver distraction caused by the load of using infotainment systems. In a previous study, we found that this method can be used to assess the task loads of both visual-manual tasks and auditory-vocal tasks. The task loads are assessed using the performances of both pedal tracking task (PT) and detection response task (DRT) while performing secondary tasks. We can perform this method using simple equipment such as game pedals and a PC. The aim of this study is to verify the reproducibility of the PT-DRT. Experiments were conducted in three test environments in which test regions, experimenters and participants differed from each other in the US, and the test procedures were almost the same. We set two types of visual-manual tasks and two types of auditory-vocal tasks as secondary tasks and set two difficulties for each task type to vary the level of task load.

This paper summarizes the piston pin noise mechanism and show the way to reduce noise level of semi-floating system. A mechanism of piston pin noise of semi-floating system was clarified by measurement of piston and piston pin behavior and visualization of engine oil mist around piston and piston pin. Piston and piston pin behavior was measured by accelerometer and eddy current type gap sensor with linkage system at the actual engine running condition. Engine oil behavior was visualized and measured its flow vector by Particle Tracking Velocimetry (PTV). For PTV, engine oil mist particle image was taken by high speed camera with fiber scope attached to linkage system. From themeasurement, it was cleared that engine oil doesn't reach to piston hole from undersurface of piston land and come rushing out from piston broach via groove. The result shows that lacking of engine oil between piston and piston pin makes noise larger.

The use of electric vehicles (EV) is becoming more widespread as a response to global warming. The major issues associated with EV are the annoyance represented by charging the vehicles and their limited cruising range. In an attempt to remove the restrictions on the cruising range of EV, the research discussed in this paper developed a dynamic charging EV and low-cost infrastructure that would make it possible for the vehicles to charge by receiving power directly from infrastructure while in motion. Based on considerations of the effect of electromagnetic waves, charging power, and the amount of power able to be supplied by the system, this development focused on a contact-type charging system. The use of a wireless charging system would produce concerns over danger due to the infiltration of foreign matter into the primary and secondary coils and the health effects of leakage flux.

When a vehicle drives over road seams or a bumpy surface, low-frequency noise called drumming is generated, causing driver discomfort. The generation of drumming noise is closely related to the vibration characteristics of the suspension, body frame, and body panels, as well as the acoustic characteristics of the vehicle interior. It is therefore difficult to take measures to get rid of drumming after the basic vehicle construction has been finalized. Aiming to ensure drumming performance in the drawing review phase, we applied the Finite Element Method (FEM) to obtain acoustical transfer functions of the body, and Multi Body Simulation to get suspension load characteristics. This paper presents the results of the study of drumming prediction technology using this hybrid approach.

The use of low-density materials in body panels is increasing as a measure to reduce the weight of the vehicle body. Honda has developed an aluminum/steel sheet hybrid door that is more effective in reducing weight than an all-aluminum door. Because aluminum was used in the door skin, bimetallic corrosion at the connection between the aluminum and the steel sheets represented an issue. It was possible that the difference in the electrical potential of the two metals might promote corrosion at the connection between the aluminum door skin and the steel sheet door panel, in particular at the lower edge of the door, where rainwater and other moisture tend to accumulate, with the result that the appeal of the exterior of the door might decline.

The strength characteristic of CFRP composite materials is often dependent on the internal micro-structural fracture mode. When performing a simulation on composite structures, it is necessary to take the fracture mode into account, especially in an automobile body structure with a complex three-dimensional shape, where inter-ply fractures tend to appear due to out-of-plane load inputs. In this paper, an energy-based inter-ply fracture model with fracture toughness criteria, and an intra-ply fracture model proposed by Ladeveze et al. were explained. FEM analyses were performed on three-dimensional test specimens applying both fracture models and the simulated results were compared with experimental ones. Reproducibility of the fracture mode was confirmed and the importance of combining both models was discussed.

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.

Piston ring wear in gasoline engine induces deterioration of emissions performance due to leakage of blow-by gas, instability of idling caused by reduced compression in combustion chamber, and to generate early degeneration of engine oil. We examined anti-wear performance of DLC coating on piston ring, which had been recently reported as an effective method for improving the abrasion resistance. As a result, wear rate remained low under the condition of DLC existence on sliding surface, but once DLC was worn out completely, wear of the piston ring was accelerated and its life became shorter than piston ring without DLC. In this research, we designed reciprocating test apparatus that operates at much higher velocity range, and characterized the frictional materials of the piston ring and sleeve and the DLC as a protective film, a vapor phase epitaxy (VPE) was actively used as a means to form certain level of convex and concave shape on its surface.

This paper describes the establishment of a new method for predicting piston skirt scuffing in the internal combustion engine of a passenger car. The authors previously constructed and reported a method that uses 3D piston motion simulation to predict piston slap noise and piston skirt friction. However, that simulation did not have a clear index for evaluation of scuffing that involves piston skirt erosion, and it impressed shortage of the predictive accuracy of a scuffing. Therefore, the authors derived a new evaluation index for piston skirt scuffing by actually operating an internal combustion engine using multiple types of pistons to reproduce the conditions under which scuffing occurs, and comparing with the results of calculating the same conditions by piston motion simulation.

Initiation and propagation of ductile fractures in crashed automotive components made from high strength steels are investigated in order to understand the mechanism of fracture propagation. Fracture of these components is often prone to occur at the sheet edge in a strain concentration zone under crash deformation. The fracture then extends intricately to the inside of the structure under the influence of the local stress and strain field. In this study, a simple tensile test and a 3-point bending test of high strength steels with tensile strengths of 590 MPa and 1180 MPa are carried out. In the tensile test, a coupon having a hole and a notch is deformed in a uniaxial condition. The effect of the notch type on the strain concentration and fracture behavior are investigated by using a digital imaging strain measurement system.

Just as CO2 reduction is required of four wheeled vehicles for environmental protection, similar environmental concerns drive the development of motorcycle oil technology. Zinc dialkyldithiophosphate (Zn-DTP) type additives are widely used for engine oil formulations. However, phosphorus compounds are environmental load materials. The reduction of the quantity of phosphorus compounds in engine oils is required to reduce poisoning of three-way catalysts used to purify exhaust gases from internal combustion engines. Mr. Ito and his co-authors1) reported that they developed a sulfur-based additive as a substitute for Zn-DTP. Their non-phosphorus engine oil formulation for four-wheeled vehicles with a sulfur-based additive was examined to evaluate its anti-wear performance using the following test methods:JASO M328 for gasoline engines (KA24E) and JASO M354 for Diesel engine (4D34T4).

This paper describes the oil-film bearing analysis simulation was utilized for the optimization of pin boss form which reduces a piston-pin noise. It is clear from the mechanism analysis of the piston-pin noise which is the last research that an oil-film flow inside a pin boss is an important factor for pin noise reduction. So, in this research, the oil-film simulation of the piston-pin-boss bearing part was performed using oil-film bearing analysis tool. After setting up the simulation conditions of the oil-film bearing part so that actual pin behavior and high correlativity might be shown, a parameter, effective hydrodynamic angular velocity, and an oil flow rate of change suitable for evaluation of a pin noise were found out. The pin noise in semi floating piston was reduced to the same level as full floating type by applying pin boss form to which each evaluation parameter becomes the optimal to a piston.

Catalyst simulation, which can analyze the complicated reaction pathway of exhaust gas purifications and identify the rate-determining step, is an essential tool in the development of catalyst materials. This requires an elementary reaction model which describes the detailed processes, i.e. adsorption, decomposition, and others. In our previous work, the elementary reaction model on Pt/CeO2 catalyst was constructed. In this study, we focused on extending the Zeolite catalyst and including the gas diffusivity through the catalyst layer. The reaction rate of a Zeolite catalyst was expressed by an Arrhenius equation, and the elementary reaction model was composed of 17 reactions. Each Arrhenius parameter was optimized by the catalytic activity measurements. The constructed model was validated with NOx conversion in cyclic experiments which were repeated with Lean phase (NOx adsorption) and Rich phase (NOx reduction).

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.

A multi-objective optimization model using a piston behavior simulation for the prediction of NV, friction and scuffing was created. This model was used to optimize the piston skirt form, helping to enable well-balanced forms to be sought. Optimization calculations, involving extended analyses and numerous design variables, conventionally necessitate long calculation times in order to achieve adequate outcomes. Because of this, in the present project data was converted into functions in order to help enable the complex piston skirt form to be expressed using a small amount of coefficients. Using the limit values for manufacturability and the degree of contribution to the target functions, the scope of design variables was restricted, and the time necessary for the analysis was significantly reduced. This has helped to enable optimal solutions to be determined within a practical time frame.

The Honda NSX, made entirely of aluminum, introduces a concept of using chromium chromate as a method of chemical pretreatment. For other parts that contain a different type of metal, such as various parts of the chassis, a DACRO coating system as well as many other inventions are used. For the paint process itself, a new waterborne basecoat technology is also introduced to obtain a high-class appearance level for the NSX.

Japanese accident statistics show that despite the decreasing trend of the overall traffic fatalities, more than 1,000 pedestrians are still killed annually in Japan. One way to develop further understanding of real-world pedestrian accidents is to reconstruct a variety of accident scenarios dynamically using computational models. Some of the past studies done by the authors' group have used a simplified vehicle model to investigate pedestrian lower limb injuries. However, loadings to the upper body also need to be reproduced to predict damage to the full body of a pedestrian. As a step toward this goal, this study aimed to develop a simplified vehicle model capable of reproducing pedestrian full-body kinematics and pelvis and lower limb injury measures. The simplified vehicle model was comprised of four parts: windshield, hood, bumper and lower part of the bumper. Several different models were developed using different combinations of geometric and stiffness representation.