Search Results

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.

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.

There have been a number of attempts to clarify the relationship between motorcycle specifications and shimmy phenomenon. Some of such efforts are based on equations of motion. The methods used in those efforts are suitable for analyzing motions in a fundamental structure. However, when the degree of freedom is large, it is extremely difficult to deliver an equation of motion. Therefore, a practical method cannot be found generally when applying the methods employing equations of motion. We also conducted the analysis of shimmy using multi-body dynamics simulation. The yielded results were useful only for clarifying the differences in shimmy levels among motorcycles. However, they were not helpful to understand the relationships between specifications and shimmy phenomenon.

Currently, there is a growing demand for application of plastic coverings for motorcycles in the market. Accordingly, decorative features for plastic coverings are increasingly important to enhance the attractiveness of exterior designs of those motorcycles. Under these circumstances, the magnetically formed decorative painting had been adopted to a mass-production model sold in Thailand in 2008. Magnetically formed decorative painting is a method in which the design patterns are formed by painting a material that contains flakes movable along with magnetic fields, while applying magnetic sheets in the ornamenting design shapes underneath the part being painted. It offers a three-dimensional appearance even though its surface has no protrusions or indentations. The degree of three-dimensionality on the paint surface appearance was defined as “plasticity” [1] (a term used in pictorial arts).

In brake squeal analyses using FE models, minimizing the discrepancies in vibration characteristics between the measurement and the simulation is a key issue for improving its reproducibility. The discrepancies are generally adjusted by the shape parameters and/or material properties applied to the model. However, the discrepancy cannot be easily adjusted, especially, for the vibration characteristic of the disc model of a motorcycle. One of the factors that give a large impact on this discrepancy is a thermal history of the disc. That thermal history includes the one experienced in manufacturing process. In this paper, we examine the effects of residual stress on the natural frequency of motorcycle discs. The residual stress on the disc surface was measured by X-ray stress measurement method. It was followed by an eigenvalue analysis. In this analysis, we developed a unique method in which the residual stress was substituted by thermal stress.

The technology to estimate engine load using the amplitude of crankshaft angular velocity variation during a cycle, which is referred to as “Δω (delta omega)”, in a four-stroke single-cylinder gasoline engine has been established in our former studies. This study was aimed to apply this technology to the spark advance control system for small motorcycles. The cyclic variation of the Δω signal, which affects engine load detection accuracy, was a crucial issue when developing the system. To solve this issue, filtering functions that can cope with various running conditions were incorporated into the computation process that estimates engine loads from Δω signals. In addition, the system made it possible to classify engine load into two levels without a throttle sensor currently used. We have thus successfully developed the new spark advance system that is controlled in accordance with the engine speed and load.

A new hydrogen fueling protocol named MC Formula Moto was developed for fuel cell motorcycles (FCM) with a smaller hydrogen storage capacity than those of light duty FC vehicles (FCV) currently covered in the SAE J2601 standard (over than 2kg storage). Building on the MC Formula based protocol from the 2016 SAE J2601 standard, numerous new techniques were developed and tested to accommodate the smaller storage capacity: an initial pressure estimation using the connection pulse, a fueling time counter which begins the main fueling time prior to the connection pulse, a pressure ramp rate fallback control, and other techniques. The MC Formula Moto fueling protocol has the potential to be implemented at current hydrogen stations intended for fueling of FCVs using protocols such as SAE J2601. This will allow FCMs to use the existing and rapidly growing hydrogen infrastructure, precluding the need for exclusive dispensers or stations.

Most types of paint materials currently used for motorcycles contain large amounts of VOCs (Volatile Organic Compounds). VOCs are environmental load substances, and there is a demand to reduce emissions in recent years. Many of a motorcycle's exterior parts are made of ABS (Acrylonitrile-Butadiene-Styrene) plastics (henceforth ABS) or PA (Polyamid) plastics (henceforth PA). These two plastic materials have different film adhesion mechanisms and adhesion strength. Therefore it was necessary to use different conductive primers and that's was one of the factors which made time and material losses in the painting processes. We solved those two issues, the reduction of VOCs and the common use of the same conductive primer for different parts materials, by combining two kinds of resins originally designed as the conductive primers, i.e., urethane resins with carboxylic acid groups and acrylic resins with amide groups, which are different in properties.

As the motorcycle market grows, the fuel efficiency of motorcycle oils is becoming an important issue due to concerns over the conservation of natural resources and the protection of the environment. Fuel efficient engine oils have been developed for passenger cars by moving to lower viscosity grades and formulating the additive package to reduce friction. Motorcycle oils, however, which operate in much higher temperature regimes, must also lubricate the transmission and the clutch, and provide gear protection. This makes their requirements fundamentally very different from passenger car oils. Developing fuel efficient motorcycle oils, therefore, can be a difficult challenge. Formulating to reduce friction may cause clutch slippage and reducing the viscosity grade in motorcycles must be done carefully due to the need for gear protection.

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).

The environmental performance of automobiles and automobile engines in particular is the foremost issue in the automotive industry today. In addition, engine durability performance is an essential aspect of engine oil performance. Four-cycle motorcycle engine oils formulated with dialkyl phosphate, a sulfur-free additive developed as an alternative to ZDDP, provide excellent environmental and durability performance in terms of longer drain intervals, cleanliness and low corrosion properties.

A compact, low-cost fuel pump module has been developed for use in motorcycles with a small-displacement engine. Various considerations are given to make the module as compact as possible. The pump motor, which is one of the major component parts, is down-sized specifically for applications to small-displacement engines. The pressure regulator uses a simple construction consisting only of a ball and a spring without a diaphragm. Especially noteworthy is that with the volume reduced by approximately 40% from the conventional pressure regulator while using the construction that reduces self-excited vibrations caused by fuel pressure pulsations, the pressure regulator contributes significantly to the down-sizing and cost reduction of the module. Furthermore, the down-sized module remarkably reduces the size of fuel pump mount surface, allowing a modification from the flat-surface sealing to the radial sealing.

As a result of recent EPA (U.S. Environmental Protection Agency) gasoline permeation control regulations, the fuel tanks on motorcycles and ATVs (All-Terrain Vehicles) are required to change to lower gasoline permeation performance on 2008 models. Therefore, we determined to use a multilayer plastic fuel tank. There are some molding issues that are peculiar to motorcycle and ATV fuel tanks. First, when the insert is blow molded, there is a reduction in welding strength. Second, peeling of the adhesion occurs on impact in the inserted parts. Third, saddle shapes with large ductility deformation are easy to be punctured during molding. Finally, the appearance of the fuel tank is not acceptable. In order to address the first issue, the welding performance, the drawdown of parison and the melting damage of insert parts were balanced, focusing attention to the temperatures of the parison and the insert.

Honda R&D has developed a throttle-by-wire (TBW) system that meets the needs of motorcycles where the attitude of the vehicle body is controlled by operation of the throttle. To gain high response and following for the throttle valve, we employed a new adaptive control algorithm. The newly developed system has an idling combustion stabilization function and a three-dimensional control function for the throttle-opening map based on running gear and engine speed. With those functions, we improved the controllability of the motorcycle, especially for small throttle openings. Furthermore, we improved the feeling of the limiter control used in maximum-speed limitation. For the overall system, intake system related devices are consolidated to improve the layout flexibility and expand the mounting options on the motorcycle.

Super-sport motorcycles have shorter wheelbases than other category motorcycles. Due to this, strong braking occasionally causes large pitching motions to occur, including rear-wheel-lift. In order to reduce such pitching motions and achieve an effective braking force, the authors have developed a brake-by-wire system that uses a pressure sensor to detect the braking input pressure and an electric actuator to variably control the hydraulic pressure. This system makes it possible to precisely control the braking force compared with the previous ABS. Large pitching control was performed by the distribution of a front wheel and a rear-wheel braking forces, CBS (Combined Brake System), by using electronic control, and Brake-by-Wire has been suitable for sport riding. As a result, stable braking performance could be obtained without spoiling the handling characteristics of super-sport motorcycles.

Because the seat bottom of a scooter, which has luggage box under the seat, needs a high rigidity, and it tends an increase of the weight, therefore lightening is required. The application of the injection foam molding was examined to lighten the seat bottom of polypropylene (PP) resin. The injection foam molding is a molding method applicable by a simple modifying to ordinary injection molding machine, and it will enable lightening and making a high rigidity. By CAE analysis and the injection foam molding method, over 15% of lightening and the equal cost were achieved compared with the ordinary one.

Using sand cores, the weld-able, hollow die-cast parts have been developed. For casting, the transition flow filling method is applied to reduce gas containment and to minimize damages to the core. In designing the products, the newly developed core stress prediction system by melt pressure distribution and the newly developed in-product gas containment prediction system have been applied. The hollow die-cast frame made by the new method attains a 30% increase in rigidity and 1kg reduction of weight.

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 new automatic transmission, A-HMT (Advanced Hydro-Mechanical Transmission) has been developed for the Honda ATV (All Terrain Vehicle), which is for wide applications such as utility, recreation, etc. The A-HMT system features high performance, durability and reliability attained by improving the structures from the original hydro-mechanical automatic transmission used for the scooter called “Juno”, which Honda had produced many years ago, working on the same principle. In addition to it, by applying the electronic control system, the highly responsive driveability that suits the requirements of ATV's has been realized. The A-HMT is installed in the new 500 cm3 ATV, FOURTRAX FOREMAN RUBICON, which has been introduced in the USA market since June 2000.

The variable intake and exhaust control valve system for the in-line four-cylinder motorcycle engine was developed for realization of high engine power in all the engine speed ranges. Both the variable intake and exhaust control valves are operated by one servomotor. For high engine speeds, the exhaust collector pipe design for merging of each exhaust gas flow at 180 degrees phase difference is used. For mid engine speeds, the design for merging of each exhaust gas flow at 360 degrees phase difference is used. Two modes are provided to the intake control, and three modes are provided to the exhaust control. Along with exhaust-gas treatment systems such as the catalyst and air-injection system, high engine performance with optimum driveability and reduced emission are realized.