Basic requirements for a motorcycle brake system include achieving adequate deceleration and improving motorcycle stability during braking by easy operation. To help realize these requirements, Combined Brake System (CBS) and Antilock Brake System (ABS) for motorcycle have been researched and developed. A new brake system which combines CBS with ABS has been recently researched and installed on a test motorcycle. The results of braking tests showed high performance in deceleration and good braking feeling especially during ABS actuation.
Four forces act in rings for a metal pushing V-belt. These forces are: two kinds of intercepting forces which prevent blocks from going outside of pulleys (one caused by pulley thrust, the other caused by centrifugal force), frictional force acting between the rings and the blocks, and bending force in longitudinal direction. In the previous paper (1)(2)(3)(5), distribution of three forces, excluding centrifugal force, were presented at low belt speed. We successfully measured all four kinds of forces including centrifugal force continuously at practical operation conditions for layered rings. In this paper, distribution of these four forces on the innermost ring is described at steady states.
Gas shielded metal arc welding is generally applied to automobile chassis parts. However, the weld parts with the E-coat show poor corrosion resistance. Therefore, the corrosion mechanism of the weld parts was investigated. The results found two reasons why the weld parts corroded faster than the non weld parts:(1)inadequate phosphating (2)defects in the E-coat. After detailed investigation, it was clarified that the major cause of poor corrosion resistance was the defects in the E-coat caused by slags formed on the surface of the weld bead. Therefore the amount of slag has to be decreased to improve the corrosion resistance. The effect of shielding gas composition on the amount of slag was then investigated. In the case of Ar and oxidizing gas mixture, the corrosion resistance improved as the oxidizing gas content decreased. This was due to the reduction of slags.
The moment of inertia of the crankshaft cannot be ignored when analyzing the dynamics of a motorcycle. In this research, the tire friction force (calculated by drag and tire side force) was used as an index of the drive performance. The ratio of roll rate and steering torque (here after referred to as a roll rate gain) was used as an index of the cornering performance, and it was analyzed as the influence of the moment of inertia of a crankshaft on the drive performance as well as cornering performance. As a result, the influence on drive performance and cornering performance by the moment of inertia has been found.
High viscosity index(HVI) petroleum base stock, with excellent temperature-viscosity characteristics, oxidation resistance, and low-evaporation properties, offers advantages as the base stock for high fuel economy engine oils, particularly because of its low-friction properties in the boundary and/or “E.H.L (Elastohydrodynamic Lubrication)” area due to its rheological characteristics. This research evaluated HVI base stock's low-friction properties. Upgrading the oil from 5W-30 to 5W-20 was also investigated. The friction properties of the HVI base stock were measured by a unit friction platform. The results show a 28% reduction in friction coefficient compared with the conventional, solvent refined oil, which is attributable to the high-pressure viscosity of the base oil.
Using stabilizing yaw-moment diagrams, the authors analyzed three methods of active chassis control for their effect and effective ranges during cornering maneuvers. The following results were obtained: controlling the transverse distribution of driving and braking forces cancels the changes in a vehicle's dynamic characteristics caused by acceleration and deceleration. Controlling the distribution of roll stiffness is only effective in ranges with high lateral acceleration, and the effect varies depending on the longitudinal weight distribution. Controlling the rear wheel steering angle is most effective in a range with a small side slip angle, but this effect decreases with an increase in the angle, especially during deceleration.
There are several all-aluminum cylinder blocks. A typical example is a mono-block cylinder of alusil alloy produced by low pressure die casting. This material's resistance to abrasion and seizure, however, is not satisfactory for motorcycle; in addition, long processing time is another disadvantage. To cope with these problems, the authors developed a light and highly productive all-aluminum cylinder block with a cast-in liner through die casting. The liner is made from powder metallurgy composite (PMC) with 3 to 5 % alumina and 0.5 to 3 % of graphite additives. The PMC reconciles abrasion resistance and machinability. The hardness deterioration of the composite due to the heat at die casting is avoided by using heat-resistant rapidly-solidified powders, made from an aluminum-silecon-iron alloy, for the matrix.
An electronically controlled fuel injection system for controlling the air/fuel (A/F) ratio has been looked forward as a means for improving drivability, output characteristics, and fuel consumption of two-stroke cycle motorcycle racer engines. However, actual installation of such a system on a high output two-stroke cycle engine (which utilizes exhaust gas pressure pulsation effects) has been considered difficult for the following reasons. Fluctuation in the delivery ratio (L) during firing and misfiring becomes great due to effects from the exhaust pipe. Applying the control method used for conventional four-stroke cycle engines (by which the delivery ratio (L) is measured) would necessitate a large and heavy system. The authors have eliminated such problems by developing an electronically controlled fuel injection system, the PGM-FI (Programmed-Fuel Injection) system, which employs basic intake air flow data according to engine speed (NE) and throttle opening (θTH).
Honda developed a 750cm3 V-4 engine adopting an elliptical piston, and began selling the “NR” motorcycle with the engine installed in 1992. The adoption of an elliptical piston and cylinder achieved a compact layout of eight valves, which consists of four intake valves and four exhaust valves per cylinder. This paper explains the features of an engine with such a layout, focusing on the following: 1) Multiple valves and short-stroke enable the 750cm3 engine to achieve 15,000rpm. 2) The engine is more compact and lightweight than an engine having the same displacement, and more powerful than one with twice as many cylinders (8 cylinders). Also, this paper describes the techniques giving improved blowby gas and oil consumption characteristics as related to the sealing property of the piston, cylinder and piston ring and achieving performance equivalent to a conventional motorcycle engine.
A multi-use road simulator for reproducing various road loads on motorcycles and buggies has been developed on a test bench by using computer-controlled hydraulic actuators. The device is controlled by a low-priced personal computer and an interface system with custom software. An unique feature is the capability to simulate loads related to such phenomena as the bottoming of suspension and the movement of a telescopic type front fork on the road.
The PVC(poly-vinyl chloride) underbody coating was specifically designed for the automotive underfloor area in order to prevent chipping damage as well as the onset of rust propagation from a scratched point. This superior anti-chipping performance can also be achieved without increasing film thickness of the PVC by balancing film strength and adhesion strength. Also, by incorporating plastic balloons in the PVC formulation, a dried film specific gravity of less than 1.0 is achieved, and consequently a 2 kg weight reduction becomes possible when compared to conventional materials used for underbody coating.
The one-way clutch mechanism seen on bicycles, etc. greatly ease the load of riders at times of coasting or descending downhill. Their use on motor vehicles are restricted to some automatic drive four-wheeled vehicles with torque converters. There are neither any example of mass-produced motorcycle with one-way clutch between the engine and the drive system nor any reports of quantitative study on its impact on the performance of the vehicle including fuel economy. The present paper reports the results of experimental research on one-way clutch employed in the drive system, obtained for motorcycles having five kinds of two-cycle engines of different displacements. The test on fuel economy showed an improvement of 4 - 9%.
A theoretical and experimental investigation of the effects of antilock braking (ALB) on motorcycle braking in a turn (BIT) is described. The analyses involved computer simulation of the dynamic interaction among rider, motorcycle, ALB, and roadway during BIT maneuvers; and instrumented full scale BIT tests with expert and novice riders. The analyses and full scale tests used an example all mechanical, independent front and rear ALB system. The results showed that ALB can help maintain motorcycle stability in straightline and gradual turns at high and excessive brake force levels. In more severe turns, the motorcycle can capsize at low brake force levels, below those which are typically needed to trigger ALB operation. As a consequence, from a fundamental standpoint, contemporary conventional ALB systems cannot be considered to influence or improve motorcycle stability during limit braking in moderate or near limit turns.
The application of inverter technology has enabled the realization of a lightweight, portable power generator. It produces an 80% duty, square wave alternating current (AC). Protective features are incorporated to safeguard internal transistors and other electrical components, as well as various pieces of electrical equipmemt utilizing the power it produces.
The recent development of electronics has led to increased research efforts to put the active control technique to practical use in various fields of automotive technology. This report tries to identify the goals likely to be achieved by the active control technology and the subjects of study involved in research activities for this end. As a promising approach to the solution of these subjects, the report discusses the problem areas of the existing evaluation method for vehicle handling performance and then proposes feasible ideas in this field. Finally the report gives a few examples of the research methods we have successfully applied to the development of a four wheel steering system.
In motorcycles traveling at medium to high speed, roll stability is usually maintained by restoration forces generated by a self-steering effect. However, when the vehicle is stationary or traveling in low speed, sufficient restoring force does not occur because some of the forces, such as centrifugal force, become small. In our study, we aimed at prototyping a motorcycle having roll stability when the vehicle is stationary or at low speed with a steering control for self-standing assist, while maintaining stability properties in medium to high speed. A model was built to represent dynamics of roll motion, which is composed of a fixed point mass located above the vehicle’s center of gravity and another movable point mass below that gravity center. According to the model, when steered, the roll moment direction generated by the shift of the movable point mass becomes the same as the direction generated by the ground contact point shift of the front tire.
Regulations that limit emissions of pollutants from gasoline-powered cars and trucks continue to tighten. More than 75% of emissions through an FTP-75 regulatory test are released in the first few seconds after cold-start. A factor that controls the time to catalytic light-off is the heat capacity of the catalytic converter substrate. Historically, substrates with thinner walls and lower heat capacity have been developed to improve cold-start performance. Another approach is to increase porosity of the substrate. A new material and process technology has been developed to significantly raise the porosity of thin wall substrates (2-3 mil) from 27-35% to 55% while maintaining strength. The heat capacity of the material is 30-38% lower than existing substrates. The reduction in substrate heat capacity enables faster thermal response and lower tailpipe emissions. The reliance on costly precious metals in the washcoat is demonstrated to be lessened.
This study aims to build a conceptual simulation used at the early stage of PHEV development. This simulation enables to design vehicle concept and fundamental architecture with regard to fuel economy, vehicle acceleration and electric range. The model based on forward-looking method comprises of plant-model and controller-model which are made by one-dimensional simulation tool “GT-SUITE” and Matlab/SIMULINK respectively. In order to automatically couple between them and to implement iterative calculations of SOC (State-of-Charge) convergence, optimization and automation tool “modeFRONTIER” was used. As a case study of this simulation, we adopted series-parallel type plug-in hybrid electric vehicle (PHEV) and demonstrated the results on fuel economy of a legislative driving cycle and 0-60mph vehicle acceleration. Moreover, procedures to identify component specifications meeting vehicle targets and requirements at the early stage of vehicle development were concretely described.
At past ESV conferences, we have reported on a series of studies on how the driver's control performance is affected by vehicle steering response. These studies showed that a four-wheel steering system can reduce the delay in lateral acceleration response to steering action, which may result in better control performance of the driver. The present report examines the handling performance of an experimental vehicle fitted with a four-wheel steering system under a wider range of operating conditions. The studies were conducted using mathematical models and simulation of the driver-vehicle system, plus road tests. The findings indicate that the four-wheel steering system may provide better vehicle handling performance than a conventional two-wheel steering system. A vehicle incorporating this steering system may exhibit improved accident avoidance capabilities.