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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.

A new 0.9-liter 4-valve-per-cylinder liquid cooled engine was developed for 1984 model motorcycles. This new engine was optimized from the standpoint of performance, durability, and weight efficiency. Semi-Flat slide carburetors, high compression ratio, relatively short stroke and large valves were employed. This engine was upgraded every other year with changes in displacement. Induction system, exhaust system, and valve train. This paper describes, from the viewpoint of the designer, the evolution of the 4-valve liquid-cooled engine from the 1984 to 1988 models. In that evolutionary process we employed: (1) semi-down draft carburetors with smooth air ducts, (2) a computer-aided intake and exhaust port design and manufacturing system. (3) individual rocker arms. (4) a cool air intake system. (5) lightweight pistons. (6) angle -controlled tightening of connecting rod bolts.

In the closed environments such as manned space station, it is necessary to remove contaminant gas to keep a suitable environment. Removal of gaseous contaminants generated from crew, animals, and plants is important function to keep the environment below the allowable level in the Closed Ecology Experiment Facilities (abbreviated as CEEF). CEEF consist of three modules for habitat, animal and plant, the supporting facilities for each module and a plant cultivation facility. CEEF are scheduled to be constructed from 1994 in Aomori Prefecture, northern part of Japan. For designing Trace Contaminant Control Assembly (TCCA) for CEEF, the following six (6) trace contaminants have been selected as major contaminant gas in CEEF; Ammonia (NH3) Methane (CH4) Ethylene (C2H4) Carbon Monoxide (CO) Nitrogen Dioxide (NO2) Sulfur Dioxide (SO2) Ethylene is well-known as an aggressive contaminant to plant growth and maturity.

Motorcycle engines are operated at an extremely broad range of revolutions, from 1000 min-1 to 10000 min-1 or more. Ideally, the natural frequency of each part should never match the engine excitation frequency at any point over that entire range of revolution speeds, but practically, there are times when resonance cannot be avoided because the range is so broad, and therefore the vibration amplitude at resonance must be kept low. For this reason, it is important to grasp not only the resonance frequency but also the vibration amplitude at that point. This may be achieved by two methods, measurement and analysis. The direct measurement of vibration is generally difficult because the motorcycle muffler system has a complex shape and in addition it gets very high temperature when the engine is operating. For this reason, with the aim of being able to predict muffler vibration at the design stage, we carried out a vibration test and FEM (finite element method) analysis.

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.

This paper describes the predicted results of acoustic transmission loss (T.L.) for a motorcycle muffler. First, the T.L. of a prototype muffler with one expansion chamber was obtained by measuring sound levels at the inlet and outlet ports of the muffler by speaker test. T.L. was then calculated by using a three-dimensional Finite-Element Method (FEM) for acoustic fields in the muffler. There was good coincidence between the calculated T.L. and experimentally observed data. Second, T.L. of the prototype muffler while attached to a motorcycle engine was measured. On this step, however, a similarly calculated T.L. using FEM to consider the effect of exhaust gas temperature in the muffler showed differences from the measured one. It was estimated that muffler body vibration sounds may affect the result. A dynamic analysis of the structure was carried out using FEM to obtain the eigen modes of the muffler body.

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.

In port injection, it is difficult to control in-cylinder fuel supply of each cycle in a transient state as cold start (in this paper, cold start is defined as several cycles from cranking at low engine temperature). Hence, THC, which is one of regulated emission gases, is likely to increase at cold start. As one of THC emission reduction approaches at cold start, the optimization of fuel injection specifications (including injection position and spray diameter) is expected to reduce THC emission. Setting injection position as downstream position is expected to secure the in-cylinder fuel supply amount at cold start because of small fuel adhesion amount on an intake port wall and a short distance between the injection position and in-cylinder. The position injection contributes to reduction of THC emission due to elimination of misfire.

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.

Engine sound is one of the most important factors when selecting a motorcycle from various models. Therefore, it is necessary to create an appealing sound in the rider's ears in addition to complying with noise regulations. In this paper, how we control intake sound is described through the study of a sports-type motorcycle with an inline 4 cylinder engine. To control intake sound, both intake pressure pulsations generated by the engine and acoustic transfer characteristics of the intake system are important. It is shown by unsteady-state one-dimensional computational fluid dynamics analysis that specifications of the exhaust system affect intake pressure pulsations across the valve overlap period. Therefore, to emphasize high order components of the engine revolutions in the intake sound, for example, modifying the layout of the exhaust muffler is effective.

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.

Recently, motocross racetrack configurations have been changing from speed-oriented layouts to rider's talented performance-oriented layouts. This has created a demand for engines that can provide both power at high speeds and torque at low speeds as well as having quick response at all speeds. The most efficient way to achieve all round power range in the 2-stroke-racing engine was to increase the area of exhaust port and to vary the exhaust chamber volume at the same rate as the increased engine revolution. The authors developed an automatic exhaust control valve device called “KIPS”. In this paper we will describe how KIPS was developed, its output characteristics, and operation. Figure I shows a 1992 model KX250 motocross racing bike equipped with the newest KIPS device (3-Way KIPS).

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.

Though most street-use motorcycles are now equipped with 4-stroke engines, off-road motorcycles, especially moto-cross racers, still mainly use 2-stroke engines because of their high power and light weight. 2-stroke engines for moto-cross racers require the engine characteristics of high power and excellent throttle response on a wide range of engine speeds. These characteristics immediately require an effective exhaust device to improve output performance at the middle-speed range while maintaining high power at the high-speed range. The latest 2-stroke engines maintain such performance by using an exhaust device, and also by the application of extensively improved basic elements such as the scavenging passage arrangement, exhaust timing and passage shape, etc. This paper briefly summarizes continuous efforts for the improvement of our exhaust-system device from its beginning until the present.

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.