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As for automobile, the mass production period of Electric Vehicle(EV) has begun by the rapid progress of the battery performance. But for EV-Motorcycle(MC), it is limited for the venture companies' releases. The design and evaluation methodologies are not yet established or standardized so far. This paper provides the practical and the experimental examples. To study the feasibility of EV-MC, we developed the prototypes in the present technical and suppliers' parts environments, and evaluated them by the practical view of the MC usage. The developed EV-MC has the equivalent driving performance of the 250cc internal combustion engine(ICE)-MC and a cruising range of 100km in normal use.

In the modern aircraft manufacturing, the cost reduction, the manufacturing time reduction, and the weight saving of aircraft are strongly demanded. The Refill Friction Spot Joining [1,2](FSJ, in other words FSSW, Friction Stir Spot Welding), which is one of innovative solid-state joining methodologies based on the Friction Stir Welding[3], is a promising technology that can replace rivets and fasteners. This technology is expected to offer cost reduction and weight saving for the aircraft manufacturing. In this study, to make stronger and reliable joints, the shoulder-plunging process of Refill FSJ was employed. The weldability of the Alodine or Chromic Acid Anodize coated materials along with a faying-surface sealant was investigated. The joint properties, such as tensile shear strengths and corrosion resistance, were evaluated.

In this study, the technology that can predict fatigue life for motorcycle exhaust systems is developed. To predict the fatigue life, analyzing the engine vibration, modeling the vibration characteristics of exhaust systems and evaluating the fatigue damage of welded joints are considered essential. This paper shows an integrated numerical simulation and evaluation method. Furthermore, it is also shown with the result of a component vibration test of the muffler assembly to validate the technology. The results indicate a good correlation between the numerical simulation and the test.

In this study on the motorcycle engine, we investigated the geometry of the newly developed intake port with an objective of improving the fuel consumption and the torque in practical range. Herein we present the results obtained. We believe that an effective measure for achieving the stated objective is to improve the combustion speed and combustion stability. To realize that, it is necessary to increase the turbulence during combustion and improve the homogeneity of air-fuel mixture. To investigate the feasible shape of the port, the CFD simulation (including fuel spray analysis) was performed and a geometry that improved the turbulent kinetic energy and mixture homogeneity at the time of ignition was selected. For confirming the combustion improvement effect achieved by tumble strengthening, an engine test was conducted with the same amount of intake air as that used in.

The rocker arm has a function to lead the cam shaft rotation to the valve operation. There are cases when damages are caused due to abnormal wear at the sliding part, causing certain problems. Authors classified the wear phenomenon, and realized a systematic analysis on the possible cause of the damage. As a result, it was revealed that the damage was of two types, and to prevent the hard wear, it is effective to apply shot peening before plating. The prototype rocker arm was test under various lubricating conditions, thus actually confirming that the occurrence of wear was largely reduced.

Electroimpact and Kawasaki Heavy Industries (KHI) have produced a new riveting process for the forming of Briles type rivets in Boeing 777 and 777X fuselage assemblies. The Briles rivet is typically used for fuselage assembly and is unique in that it has a self-sealing head. Unlike conventional headed rivets such as the NAS1079, this fastener does not require aircraft sealant under the head to be fluid tight. This unique fastener makes for a difficult fastening process due to the fact that interference must be maintained between the hole and fastener shank, as well as along the sides of the fastener head. Common issues with the formed fasteners include gapping under the fastener head and along the shank of the fastener. Electroimpact has employed a host of different technologies to combat these issues with Briles fastening. First, Electroimpact’s patented “Air Gap” system allows the machine to confirm that the head of the rivet is fully seated in the countersink prior to forming.

Several elements affect the structure of eutectic silicon in hypoeutectic aluminum alloys [1, 2, 3, 4]. Among them, calcium has been investigated to a lesser extent compared to the typically used sodium and strontium. In order to enhance the thermal fatigue strength of a small engine, the morphology of eutectic silicon in hypoeutectic aluminum-silicon alloys is controlled by the addition of calcium. In addition, the castability and mechanical properties are investigated. Hence, samples containing different amounts of calcium are prepared at different cooling rates during solidification. The results revealed that, with the increase in the calcium amount and the cooling rate, eutectic silicon exhibits a fine morphology in cross-sectional images. Particularly, with the addition of at least 62 mass ppm of calcium in a specific range of cooling rates, refined eutectic silicon is obtained.

When an electronically controlled fuel injection device is located at downstream in intake port (hereinafter defined as downstream injection, on the other hand, upstream injection is defined as that fuel injection device is located at upstream in intake port), the possibilities of an improvement in the engine startability, increase in maximum power, and decrease in THC during warming have been reported in visualizations of the intake port. In addition, the amount of wall adhesion decreased with downstream injection in previous paper [1]. In this paper, we examine the influence on the amount of wall adhesion due to the difference in injection position on fuel transport in the intake port during transient operation and the obtained exhaust A/F and the amount of exhaust gas emitted during transient operation are evaluated.

In the expansion of composite material application, it is one of the most important subjects in assembly of aircraft structure how drilling of composite/metal stack should be processed in an efficient way. This paper will show the result of development of a drill bit for CFRP/Aluminum-alloy stack by Kawasaki Heavy Industries (KHI) and Sumitomo Electric Hardmetal (SEH). In order to improve workability and economic performance, the drill bit which enables drilling CFRP/Al-alloy stack: at 1 shot; from both directions; without air blow and coolant (just usual vacuuming); was required. A best mix drill bit which has smooth multi angles edge and pointed finishing edge was produced as a result of some trials. Developed drill bit achieved required performance and contributed to large cost reduction, labor hour saving, production speed increase and work environment improvement.

The two-stroke engine has a small displacement and high output, and therefore saves space when the engine is installed in a vehicle. Thus, the application of two-stroke engines to HEVs is a very effective means of reducing vehicle weight and securing engine space. On the other hand, the unfired element increases in the exhaust gas with a two-stroke engine because the air-fuel mixture is blown through to the exhaust system during the scavenging process inside the cylinder. Moreover, combustion becomes unstable due to the large amount of residual burnt gas in the cylinder. To solve these problems, we propose a two-stroke engine that has intake and exhaust valves that injects fuel directly into the cylinder. We describe the engine shape and the method that can provide high scavenging efficiency and stable combustion in such a two-stroke engine.

In the development of a motorcycle frame, the balance between high performance and reliability and a short development period are important. In this study, a fatigue durability evaluation technique for a motorcycle frame was developed to enable highly accurate development within a short period of time. Furthermore, we developed a shaking table excitation system as a means to supplement the road test.

The authors developed a gasoline engine that combined direct injection and port fuel injection in order to improve fuel economy for motorcycles. Compared to passenger car engines, motorcycle engines generally have smaller displacement and operate at higher engine speed, so the bore and stroke are generally smaller than those of passenger cars. Therefore, the direct injection spray characteristics optimized for small bore and stroke were selected to reduce fuel adhesion to various parts of the combustion chamber wall. In addition, this engine employed the high tumble intake port that can both strengthen turbulence intensity and suppress the decrease in volumetric efficiency to a lower level. Also, stratification of air-fuel mixture and split injection were employed for reducing catalyst warm-up time and soot. The results showed that excellent fuel economy was achieved without sacrificing engine output performance while meeting emissions regulations.

Environmental and energy independence concerns have stimulated the development of an apparatus for alternative fuel. It estimates the ethanol content in the fuel in order to perform a reliable combustion. One means for measuring the ratio of ethanol present in the fuel tank is to provide a fuel composition sensor. However, such a fuel composition sensor increases the number of parts and causes the cost issues in motorcycles. We used an oxygen sensor disposed to the exhaust pipe to estimate the ethanol content without increasing the parts and costs. The common method of the estimation is the oxygen feed-back in stoichiometric air fuel ratio condition. Unfortunately, two-wheel vehicles are often operated in rich conditions and have less chance of stoichiometric condition. In this study, we used a one-liter four-cylinder motorcycle, and have developed a practical method to estimate the ethanol content even in the not-stoichiometric condition.

The regulation for emission gas of the motorcycle is rapidly being strengthened as the concern about global environment grows around the world, and manufacturers are facing the problem to reduce the toxic materials in the emission gas more. As the technology to reduce the toxic materials, it is common to install a three way catalyst (TWC) on an exhaust system and optimize the oxygen concentration at the inlet of TWC by maintaining air fuel ratio (A/F) on stoichiometric A/F with the control of fuel injection quantity. Furthermore, TWC itself is designed to maintain proper oxygen concentration by the addition of a substance with oxygen storage capacity (OSC), which is able to suppress the variation of the oxygen concentration.

At the upstream part of the Three-Way Catalyst (TWC) an O₂ sensor (UpO₂S) is used for O₂ Feedback Control (O₂F/B) that controls the air-fuel ratio (A/F) close to the stoichiometric level. O₂ sensor has a bit of individual characteristic difference as for the switching the excess air ratios of output (λ shift). This phenomenon becomes remarkable according to the effects of unburnt elements in exhaust gas. Despite the O₂F/B implementation, A/F isn't controlled to the stoichiometric level and the conversion efficiency of the TWC could be lower. Maintaining a higher level of TWC conversion efficiency requires more accurate A/F control and corrections of the UpO₂S λ shift issue. Therefore, using an O₂ sensor at the downstream part of the TWC (DownO₂S)~where the effects of unburnt elements in exhaust gas are smaller~can be an effective way to restore these challenges.

Abnormal combustion, which is a cause for engine failure, is explicated to be high speed knocking by multi-cycle analysis of the cylinder pressure data of snowmobile two stroke cycle engines operated at high speed and wide open throttle condition. A mini-computer was used for the analysis of the cylinder pressure data. Calculation of the entire cycle was conducted until an engine actually failed and the relationship between the engine failure and the conditions surrounding the knocking was made clear. Using the rate of pressure change as a quantitative evaluation method for high speed knocking, a combustion chamber shape with less knocking occurrence possibility was selected.

Generally, it is thought that control is simpler than an Internal Combustion Engine (ICE)-Motorcycle(MC) as for the Electric Vehicle(EV) type MC. However, there is few characteristic to the ICE-MC to the EV-MC and it cannot get good performance without control for EV-MC. We study the methodology for design and evaluation an EV-MC. In this approach, we developed the prototype EV-MC having manual transmission. In our study, we think that EV-MC having manual transmission is feature in comparison with other general EV-MC. From this feature, we had to develop the function control in addition to standard EV-MC function control. This paper provides a function control for EV-MC having manual transmission. In this paper, we arrange the problem points of EV-MC which put electric propulsion motor and manual transmission together at first. And report the result that studied a method to solve the problem points.

As for automobile, the mass production period of Electric Vehicle(EV) has begun by the rapid progress of the battery performance. But for EV- Motorcycle(MC), it is limited for the venture companies' releases. The design and evaluation methodologies are not yet established or standardized so far. This paper provides the practical and the experimental examples. To study the feasibility of EV-MC, we developed the prototypes in the present technical and suppliers' parts environments, and evaluated them by the practical view of the MC usage. The developed EV-MC has the equivalent driving performance of the 250cc internal combustion engine(ICE)-MC and a cruising range of 100km in normal use. In the prototype development, the reliability and the ability of protection design of the battery in the whole vehicle against the environmental loads are mainly studied, especially, heat and cold, water, shock, and the accident impact.

In recent years, there has been a need to reduce CO2 emissions from internal combustion engines in order to achieve an energy-saving and low-carbon society. Against this backdrop, the authors have focused attention on Homogeneous Charge Compression Ignition (HCCI) combustion that achieves both high efficiency and clean emissions. With HCCI combustion, a premixed mixture of fuel and air is supplied to the cylinder and autoignited by piston compression to drive the engine. Autoignition makes it possible to operate the engine at a high compression ratio, enabling the HCCI combustion system to attain high efficiency. However, HCCI combustion also has some major unresolved issues. Two principal issues that can be cited are ignition timing control for igniting the mixture at the proper time and assurance of suitable combustion conditions following ignition to prevent incomplete combustion and knocking.