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The demand to reduce noise in the passenger cars is increasing. Tire vibration characteristics must be considered when studying road noise because of the strong interaction between tire vibration characteristics and interior car noise. Car manufacturers are keenly interested in studies on the prediction of NVH (Noise, Vibration and Harshness) performance, including viewing tires as substructure. Recently, studies have illustrated the effect that tire lateral bending mode have has on road noise, while most past studies of tire vibration focused on the circumference mode, which excited the vertical spindle force. Therefore, further study of tire lateral bending mode is necessary. Modeling of the tire lateral bending mode is described in this paper. First, lateral spindle force is measured under tire rolling conditions. Second, experimental modal analysis is performed to grasp tire lateral bending mode. Finally, a tire vibration model is built using the cylindrical shell theory.

Researches for automated construction machinery have been conducted for labor-saving, improved work efficiency and worker's safety, where a tracking control function was proposed as one of the key control system strategies for highly automated productive hydraulic excavators. An optimized digging trajectory that assures as much soils scooped as possible and less energy consumption is critical for an automated hydraulic excavator to improve work efficiency. Simulation models that we used to seek an optimized digging trajectory in this study consist of soil models and front linkage models of a hydraulic excavator. We developed two types of soil models. One is called wedge models used to calculate reaction forces from soils acting on a bucket during digging operation, based on the earth pressure theory. The other is called Distinct Element Method (DEM) model used to analyze soil behaviors and estimate amounts of soils scooped and reaction forces quantitatively.

The authors have explored the potential of fuel to control spray and its combustion processes in a diesel engine. Fuel has some potential for low emission and high thermal efficiency because its volatility and ignitability are one of the ultimate performing factors of the engines. In present study, the ignition process of mixed fuel spray was investigated in a constant volume combustion vessel and in a rapid compression and expansion machine, The ignition delay based on the diagram of rate of the heat release, the imaging of natural flame emissions and the numerical simulation were carried out to clarify the effect of the physical and chemical properties of mixed fuel on ignition characteristics.

In the urea SCR system, urea solution is injected by injector installed in the front stage of the SCR catalyst, and NOx can be purified on the SCR catalyst by using NH3 generated by the chemical reaction of urea. NH3 is produced by thermolysis of urea and hydrolysis of isocyanic acid after evaporation of water in the urea solution. But, biuret and cyanuric acid which may cause deposit are sometimes generated by the chemical reactions without generating NH3. Spray behavior and chemical reaction of urea solution injected into the tail-pipe are complicated. The purpose of this study is to reveal the spray behavior and NH3 generation process in the tail-pipe, and to construct the model capable of predicting those accurately. In this report, the impingement spray behavior is clarified by scattered light method in high temperature flow field. Liquid film adhering to the wall and deposit generated after evaporation of water from the liquid film are photographed by the digital camera.

Diesel sprays injected into a combustion chamber of a small sized high-speed CI engine impinge surely on a piston surface and a cylinder wall. As a consequence, their vaporization, mixture formation and combustion processes are affected by impingement phenomena. And the other important factors affecting on the processes is the injection pressure. Then, the distribution of the vapor concentration in a single diesel spray impinging on a flat and hot wall was experimented by the exciplex fluorescence method, as a simple case. The injection pressure was varied in the range from 55 MPa to 120 MPa. It is found that the distribution of the vapor concentration in this case is much leaner than that in the case of the low injection pressure of 17.8MPa.

The purpose of this study is to clarify how the residual stress determined by the configuration of weight reduction holes affects the crack initiation in the brake discs for large motorcycles under the over loading condition. Two kinds of test samples of the one-piece type brake disc were used where the configuration of the weight reduction holes were different. The test result showed that the crack initiation life was significantly changed due to the configuration of weight reduction holes. The 3D FEM results of heat transfer and thermal stress analysis explained that the stress relaxation was dependent on the configuration of weight reduction holes of the disc because the initial thermal stress was directly determined by the simple stress distribution around each hole. This study confirmed that the configuration of weight reduction holes plays a decisive role in determining the design of the brake disc.

Braking tests under overloading were carried out using large one-piece brake disks having eyebrow-shaped holes as decoration. When the number of braking cycles was more than five, permanent deflection of the disks was observed. When the number of braking cycles was less than six, no appreciable deflection occured. The experiment revealed that such deflection occurrs during the cooling process after the final braking cycle. The mechanism for this phenomenon is explained based on the deflection-time record in conjunction with the temperature distribution of disks and its variation with respect to time. The key for this phenomenon is yielding in tension at the bridges between holes. The deflection occurs due to elastic-plastic buckling caused by shrinkage of the flange. Numerical simulations were successfully conducted by using a general 3D FEM in consideration of geometrical and material non-linearities.

The purpose of this study is to propose an effective model to estimate the excitation force accompanied with stick-slip between shoe and disc, considering the strain distribution on contact surface of the shoe, and then to propose an effective concept to design the brake which reduced the brake squeal under practical use. In order to investigate the influence of configuration of the hole, three types of discs were prepared in which the size of holes was different. The SPL (Sound Pressure Level) and the frequency of squeal for three types of discs were measured when the brake squeal was observed at conditions of low sliding speed. The change of stability of the brake shoe passing on hole was analyzed by 2-D simplified brake system model.

The premixed charge compression ignition (PCCI) combustion in a compression ignition (Cl) engine is one of countermeasures against the very much severe regulation for exhaust gas of engine out. The authors have been proposed to use the fuel mixed with high volatility component and low volatility component to actualize PCCI combustion. This kind of fuel injected forms a fine and lean spray by the flash boiling phenomena which depends on the pressure and the temperature. The role of the former fuel is to decrease in the generation of particulate matters (PM) and that of the latter one is to break out the ignition. Thus, it is very much significant to find the distribution of vapor concentration of both fuels in a spray. This paper describes both distributions in a single diesel spray by use of the technique of laser induced fluorescence (LIF) in a constant volume chamber with high temperature at high pressure as the fundamental research.

It is significant for understanding the phenomena in a stratified charge engine and an SI engine with direct injection system to carry out the fundamental research. The experiments were conducted in a constant volume chamber with atmospheric condition. The pre-mixed charge composed of ethylene and air was charged with various equivalence ratio, the second charge with the same composition was injected into the chamber, thereafter, the combustion started by a spark plug. The phenomena were analyzed by use of the experimental results of shadowgraph, [OH] natural emission, pressure history and NOx and UHC in the exhaust gas.

In Metal V-belt type CVT, an elastic deformation of blocks determines the shifting speed and the pulley thrusts at transitional state. Both driving and driven pulley thrusts were calculated by considering the forces acting on blocks at a pulley entrance, which agreed with the experimental results at not only steady state but also transitional state. The frictional performance of CVT fluids and the frictional characteristics between blocks and a pulley were evaluated by applying the mean coefficient of friction as a friction parameter. It was found from the experiments that the estimated coefficient of friction of CVT fluids was not constant with respect to operating conditions. It changed due to relative sliding speed between blocks and the pulley, sliding direction and normal pressure acting on V-surface of the block.

The combustion of a diesel spray includes very complex processes, that is, atomization, evaporation, diffusion, turbulent mixing and burning. On the other hand, there are no phenomena of atomization and evaporation in the combustion of a transient gas jet. However, the latter jet can be treated as a fundamental of the former spray. From the standpoint mentioned above, acetylene gas was injected into the ambient during short duration as a transient gas jet and its flow characteristics were investigated by means of photography with a sheet of laser light and LDV to detect the turbulent vortex generated in the boundary layer between it and surroundings, in the experiments presented here. And the experimental results show that the jet itself is divided into four peculiar regions and the modelling of each region is carried out by use of the results to understand the mixture formation process owing to the turbulent diffusive mixing.

It is very important to know the load distribution in pulleys to predict the life of toothed belts. In this study, a simple model consists of springs and friction elements has been developed for numerical analysis of the load distribution. A sample problem with steady pulley motion for a two pulley system was analyzed. The analytical result was compared with the experimental result. It was also compared with the numerical result by the alternative model using FEM. Relatively good agreements between them were obtained. A typical problem for the two pulley system subjected to fluctuating torque loadings was also analyzed by the present model. The calculated result shows a large difference in tooth load distribution between the steady state case and the unsteady state one.

The effects of CNBR (cross-linked acrylonitrile butadiene rubber) modification on the fracture characteristics of epoxy adhesives were investigated under Mode I static loading. Fracture tests were conducted by using DCB (double cantilever beam) specimens. Rubber content, adhesive thickness and loading rate were changed. The crack extension resistance (given by energy release rate) of the epoxy adhesives was much improved by CNBR modification. For the rubber modified epoxy adhesives, the crack extension resistance becomes high with an increase in adhesive thickness as well as loading rate. The reason why the CNBR modification improves the crack extension resistance was explained based on the surface observation and fractal dimension of the fractured surface.

The effects of inclusion of glass beads and rubber modification on the fatigue fracture characteristics of an epoxy adhesive were investigated. Hybrid effects were also investigated when not only the epoxy adhesive was rubber modified but also when glass beads were mixed simultaneously. Fatigue crack growth resistance was greatly increased due to glass beads, CTBN and CNBR modifications at the second stage of crack growth (da/dN=10-4-10-3 mm/cycle). However, the energy release rate at threshold for both CNBR and CTBN modified adhesives were lower than that for the unmodified adhesive. No significant hybrid effects were distinguishable.

The effects of temperature, crack tip opening rate and rubber content on static fracture characteristics of CNBR (Cross-linked acryloNitrile Butadiene Rubber) modified epoxy adhesives were investigated under mode I loading. Loading-unloading tests were statically performed by using DCB (Double Cantilever Beam) specimens. The fracture toughness increased with increasing the rubber content. The fracture toughness of CNBR modified and unmodified epoxy adhesives was much influenced by temperature and crack tip opening rate. The surface topology of fractured surface was changed by temperature and type of adhesive.

This paper deals with the particle distribution in Diesel spray under the non-evaporating condition from the analytical aspect based on our experimental results. In the analysis, TAB method of KIVA II code and the k-ε turbulent model were used, and the mono-disperse distribution of the initial parcel's diameter, whose size equals to the nozzle hole diameter, was utilized in conjunction with the breakup model. The size distribution of atomized droplets (i.e. the χ-squared distribution function) is justified with the degree of freedom. It is shown that the ambient gas, which is initially quiescent, is induced and led to a turbulent gas jet. The turbulent gas jet which has a equivalent momentum with the Diesel spray was also examined by Discrete Vortex method. The quantitative jet growth was shown to be possible for the estimation and determination in its initial boundary values at the nozzle.

In order to reveal the shifting mechanisms for CVT using a metal pushing V-belt, three shifting rates were introduced. The belt motion in the pulley groove was also characterized using mean coefficients of friction as parameters, which identify the slippage condition of the belt in the pulley groove. The experimental results showed that one of shifting rates, dR/ds was almost constant in the narrowing pulley regardless of both rotational speed and transmitted torque. Here, R is the belt pitch radius in the pulley and s is the length measured along the belt pitch line. This fact indicates that the shifting is primarily governed by elastic deformation of blocks of the belt. Power transmitting states were also evaluated using a different type of lubricating oil whose nominal coefficient of friction was higher than that for the conventional AT oil. The observed mean coefficients of friction vary due to oil although the basic response of the CVT unchanged.

Six forces act on the block of a metal pushing V-belt. Previously, we successfully measured these forces at steady states using devised blocks and a telemeter system. In this paper, six forces are measured using the same testing and measuring systems at transitional states where a speed ratio varies from low to high, or vice versa. The experimental results reveal that distributions of four forces at transitional states except normal and frictional forces between rings and blocks are different in shape from those at steady states.

Block compression force and ring tension of a metal pushing V-belt type CVT have been experimentally measured at steady states. The peculiar transmitting mechanisms for this type of belts has also been outlined based on the experimental results in the previous works. In this paper, other forces simultaneously acting on a block at steady states were measured using newly developed devised blocks. These forces are frictional force between blocks and rings, normal force between blocks and pulleys, frictional forces between blocks and pulleys in radial and tangential directions. The transmitting mechanisms for the metal pushing V-belt type CVT were drawn in detail based on new experimental data. The following conclusions are emphasized in the present work. (1) A cohesive point where the block coheres with the ring exists in the pulley having a larger pitch radius at all conditions. This is not dependent on speed ratio and transmitting torque.