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Many automated guided golf cars using the electromagnetic guide technology are used in Japan to obtain more convenient and safer golf play. Now this technology is beginning to be used outside of the golf course as an on-demand people mover system. This paper presents an example of the engineering system of automated guided golf cars along for the 2 principles of automated guided vehicle. The first principle is “the steering control system including the automatic sensitivity adjustment function”, and the other principle is “the vehicle speed control system”.

Connecting rod design factors, such as geometric shape, capscrew torque and materials can significantly affect bore distortion and assembly stress. In this paper, experiments using different materials were conducted on several connecting rod big-ends with various shapes, bosses and bolts. The results show that the distortion of the big-end bore and the bolt stress are influenced considerably by the big-end shape, the bolt axial tension and the material under inertia force. It was also observed that the bolt bending stress and the load separating the big-end joint surface could be calculated with high accuracy using three-dimensional FEM in the initial connecting rod design.

The behavior of the liquid in the motorcycle fuel tank is an interesting theme from the viewpoint of the fuel meter construction, as effected by variance in the fuel pressure resulting from acceleration or deceleration, etc. It can be assumed that the behavior of the liquid in the fuel tank will be affected by the running pattern, the shape and capacity of the fuel tank, etc. Here is a report on an experiment recently made to observe how the liquid behaves in a partially fully enclosed tank. We simplified the tank shape and the involved conditions (to actually observe the behavior of the inside liquid by the suspension method.) Then we have analized the effectes according to different liquid containers, to different velocities, and to different liquid volumes as well as the time history variance in the internal pressure.

This paper presents an approach for efficiently evaluating motorcycle main frame strength using external loads predicted from measured strain data in our development process. The loads are calculated by simple matrix inversion, and can be used as boundary conditions of static analysis that resembles actual phenomena. The advantage of this method is that it allows relatively precise reproduction of actual boundary conditions without the data usually needed for dynamic simulation such as tire and suspension characteristics which often take large amount of time and man-hour to obtain. Although this approach is simple and common practice, there are a lot of things to be concerned for gaining useful results in a broad range of stages in the motorcycle main frame development process. How we effectively make use of this approach is going to be introduced here.

Recently it is becoming more necessary than ever to carry out performance prediction and factor analysis at the initial design by-computer aided engineering (CAE), in order to ensure the high performance, safety and reliability of motorcycles and also to shorten the lead time of product development. Finite element method (FEM) plays a crucial role in this respect. In particular, since the vibration characteristic is one of the most important evaluation items, the demand for accurate vibration prediction at the initial design has become much more intense. In recent years, vibration simulation methods have achieved remarkable progress, and especially the substructural synthesis method (SSM), combined with FEM, is used as an effective tool for the requirements.

Yamaha Motor Co., Ltd. has developed the new model EC-03 designed and engineered with technology developed under the Company's Smart Power ideal. Launched on the market in September 2010, the Model is an “electric commuter” entry in the personal mobility category that is expected to show increasing demand in the future.

This paper presents a practical simulation model of the rubber V-belt CVT which is widely used as a low cost driveline element for small displacement motorcycles. The characteristic of this CVT is determined by the axial force balance between driver and driven pulleys, and the elastic force of a rubber V-belt. Because these axial and elastic forces are calculated by the kinematic and FEM analysis, a large-scale simulation model which costs long execution time for the calculation is needed to estimate the characteristic of CVT. This calculation uses the one-dimensional simulation model built up with MATLAB and SIMULINK environment, so that it was possible to get the calculation result with relatively low execution time. The elastic deformation of the rubber V-Belt was calculated by a simple spring model which was verified by experiments and FEM.

The continuously variable transmission (CVT) with a rubber belt used in scooters is also regarded as a potential automatic transmission mechanism for conventional motorcycles. By making this system more compact and building it into the engine, a motorcycle CVT engine has been developed that is about the same size as a manual transmission (MT) engine. During driving with a CVT, heat is generated by friction at the sheaves, and therefore it was necessary to secure a certain length of belt to ensure that external air flows efficiently to the sheaves. However, making the CVT more compact restricted the belt length, which decreased cooling performance and increased the number of bends in the belt, making it difficult to maintain durability. To address this issue, a plastic resin drive belt and newly designed sheaves were adopted, and durability of more than that of a scooter was achieved.

The fracture splitting (FS) method for case hardened connecting rods has been developed to improve engine performance while decreasing production costs. The FS method is widely used for automotive connecting rods because it effectively improves their productivity. Normalized forging steels, microalloyed forging steels and powder metals have generally been used as the material in the FS method as they are easily split due to their brittleness. On the other hand, the materials to be used for high performance motorcycles are case hardened low carbon steels because they allow the connecting rods to be lightweight due to their high fatigue strengths. These materials, which have a hardened area of approx. 0.5mm in depth from the surface, have a ductile texture inside. This texture obstructs the crack propagation and makes the split force too high to split without deforming the bearing area.

A connecting rod made of titanium alloy is effective for lower fuel consumption and higher power output comparing to a steel one because the titanium connecting rod enables to reduce the weight of both of reciprocating and rotating parts in an entire engine substantially. But up to now, it has been adopted only to expensive and small-lot production models because a material cost is high, a processing is difficult and a wear on a sliding area should be prevented. In order to adopt the titanium connecting rods into a more types of motorcycles, appropriate materials, processing methods and surface treatment were considered. Hot forging process was applied not only to reduce a machining volume but also to enhance a material strength and stiffness. And the fracture-splitting (FS) method for the big-end of the titanium connecting rod was put into a practical use.

A control system for auto driving of motorcycle using anthropomorphic robot has been developed to efficiently evaluate a motorcycle with high accuracy, the performance of which is becoming higher. For magnetostriction-type load sensor, which is absolutely necessary for this system, the strain gauge type load cell has been used conventionally. However, the detection sensitivity, strength, and responsibility have not been satisfied completely under engine vibration conditions. To solve this problem, a magnetostriction-type load sensor has been newly developed. As a result of the tests with actual machines, it is found that this magnetostriction-type load sensor satisfies the conditions necessary for the motorcycle drive control system and measurement system.

Recently the response of the engine speed at starting has more importance than ever for quick start satisfying rider’s needs, as well as exhaust emissions. We have developed a simulation for studying engine and starter specifications, engine control algorithm and other engine control parameters. This system can be utilized to realize appropriate starting time by considering air-fuel ratio under various conditions. This paper addresses what are taken account of in our method. Examples applying this to a conventional motorcycle engine are shown.

This paper describes the development of a new concept two-wheel steering system for realizing motorcycle motion control. By considering the whole of the main frame as the rear-wheel steering axis, it was possible to move the rear-wheel steering system from the conventional installation position at the rear arm to the head pipe. As a result, the developed two-wheel steering system is both lightweight and compact. This two-wheel steering system was installed in a motorcycle, and starting and stopping tests were carried out with two people riding on the motorcycle. The test results confirmed that the two-wheel steering system is capable of changing the motion characteristics of the motorcycle in actual riding. Furthermore, by calculating the equivalent wheel alignment of this system, this paper also theoretically demonstrates that these changes in motion characteristics are caused by changes in caster and trail.

An original multi-body dynamics simulation program for reciprocating engine system with elastically deformable piston skirt was developed in order to understand and examine the secondary motion of piston. This program uses specialized equations of motion using only the rotational degree of freedom of each components taking the valiation of rotating speed of crank into account. In order to validate the practical use of this program, the calculations were compared with the measurements on the piston motion of a two-stroke engine for motorcycles and a four-stroke engine for automobiles, and good agreements were obtained between them.

The finite element method (FEM) is generally utilized to investigate the chassis strength of a motorcycle. However, it is difficult to determine the load conditions for FEM analysis of a drop test. Therefore, a method of drop test strength prediction at the basic design stage has been developed by combining stress analysis with vehicle dynamics analysis. A mathematical model and computer simulation system have been developed to predict the load conditions obtained by accelerations at several chassis locations. The model is constructed using flexible bodies (e.g., front fork and rear arm) as well as rigid bodies. The flexible front fork model was made by combining beam theory with substructural methods. Also, the model includes a front fork friction model which describes Coulomb's friction in slide bushings. If dynamic analysis is replaced by an equivalent static analysis, the force can be predicted from the acceleration data and the mass distribution.

Any improvements of the fuel economy with engines are always required for all petroleum fuel vehicles. The goal of such improvements must lead to reduce fuel consumption of the engines. However it may cause some deterioration with riding feeling that is one of the most important characteristics of the motorcycles. Yamaha has developed the strong hybrid motorcycle "HV-X"(hereafter the motorcycle). The motorcycle consists of a 4-stroke 250 cm₃ a cylinder engine and two 300V AC motors with a planetary gear set. The motorcycle reduces fuel consumption without severe influence onto the drive performance by utilizing the electric power.

Carburized and quenched materials with high fatigue strength are often used for motorcycle engine parts. Nitrided materials exhibit less deformation during heat treatment than carburized and quenched materials, so if the same or higher fatigue strength can be achieved with nitrided materials as with carburized and quenched materials, the geometric precision of parts can be increased and we can reduce engine noise as well as power loss. When the fatigue strengths of a nitrided material with its compound layer surface put into γ’ phase through nitriding potential control (hereafter, G), and a nitrided material put into ε phase (hereafter, E) were measured, the results showed the fatigue strength of the G to be about 11% higher than that of carburized and quenched materials. It was inferred that the strength of the compound layer determines fatigue strength.

In this study, lean combustion concept was investigated to realize better Fuel Economy (FE) on a single cylinder motorcycle engine. A low-pressure direct injection (DI) system was applied to realize lean stratified combustion concept with good combustion stability. In addition, Exhaust Gas Recirculation (EGR) system applicable to small motorcycle engines was used to attain FE improvement and NOx reduction. EGR gas temperature and EGR return position were focused on and effects on FE and NOx were investigated. Computational Fluid Dynamics (CFD) was used to reveal EGR distribution and air motion in both the intake port and the cylinder. As a result, the influence of the stratified charge, EGR temperature and EGR return position on FE and NOx were explained quantitatively. These techniques were effective in reducing NOx and improving FE for a single cylinder motorcycle engine.

Direct methanol fuel cell (DMFC) system is a compact lightweight system as it eliminates the need of a complex reformer unit. Moreover, since the methanol-water-solution used as fuel does not correspond to a flammable substance, it is thought that convenience is high. We have developed the hybrid scooter integrated with the DMFC system and the Li-ion rechargeable batteries, and optimized various parameters related to the performance and the efficiency. The power output of the DMFC system was adjusted to the value necessary for a constant ground run in 30 km/h of a commercial small electric scooter. All the system components had to be constituted in the limited space and under the restricted weight conditions. The net-power-output of the system was examined under various air flow rate, fuel flow rate and methanol concentration conditions.

Attempts have been made to develop an electronically controlled fuel injection system that is ideal for small motorcycles, cost-efficient, compact, and electric power-saving while maintaining accuracy. For reducing the number of sensors and cost, highly accurate methods have been developed for the measurement of intake air mass, detection of acceleration, distinction of engine stroke, and estimation of atmospheric pressure without using a throttle position sensor, cam timing sensor, and barometric sensor in such a manner as to carry out sampling with the intake manifold pressure of single-cylinder engines synchronizing with the crank angle. For compactness and electric power saving, an injector and in-tank fuel pump module have been developed for small motorcycles.