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The objective of this study was to investigate the change of relative local velocity in each pulley groove at sliding between the belt and pulleys for a metal-pushing V-belt type CVT where micro elastic slips were inevitably accompanied to transmit power, while the transmissions were widely adopted to provide comfortable driving by continuously automatically adjusting the speed ratio. Local changes of wrapping radial position and velocity of the belt in each pulley groove of the CVT were simultaneously measured by a potentiometer with a spinning roller in the experiments. The mechanical power generated by the AC motor was transmitted through the CVT unit from the driving axis to the driven axis as usual under practical conditions while the speed ratio was set to 1.0. Pulley clamping force was applied by oil pressure.

Fuel design concept has been proposed for low emission and combustion control in engine systems. In this concept, the multicomponent fuels, which are mixed with a high volatility fuel (gasoline or gaseous fuel components) and a low volatility fuel (gas oil or fuel oil components), are used for artificial control of fuel properties. In addition, these multicomponent fuels can easily lead to flash boiling which promote atomization and vaporization in the spray process. In order to understand atomization and vaporization process of multicomponent fuels in detail, the model for flash boiling spray of multicomponent fuel have been constructed and implemented into KIVA3V rel.2. This model considers the detailed physical properties and evaporation process of multicomponent fuel and the bubble nucleation, growth and disruption in a nozzle orifice and injected fuel droplets.

In previous study, the model for flash-boiling spray of multicomponent fuel was constructed and was implemented into KIVA code. This model considered the detailed physical properties and evaporation process of multicomponent fuel and the bubble nucleation, growth and disruption in a nozzle orifice and injected fuel droplets. These numerical results using this model were compared with experimental data which were obtained in the previous study using a constant volume vessel. The spray characteristics from numerical simulation qualitatively showed good agreement with the experimental results. Especially, it was confirmed from both the numerical and experimental data that flash-boiling effectively accelerated the atomization and vaporization of fuel droplets. However, in this previous study, injection pressure was very low (up to 15 MPa), and the spray characteristics of high pressure injection could not be analyzed.

We have proposed the application of EGR gas dissolved fuel which might improve spray atomization through effervescent atomization instead of high injection pressure. In this paper, the purpose is to evaluate the influence of the application of CO2 gas dissolved fuel on the combustion characteristics and emissions inside the single cylinder, direct injection diesel engine. As a result, by use of the fuel, smoke was reduced by about 50 to 70%. The amount of NOx was reduced at IMEP=0.3 MPa, but it was increased at IMEP=0.9 MPa.

The CO2 gas dissolved fuel for the diesel combustion is effective to reduce the NOx emissions to achieve the internal EGR (Exhaust Gas Recirculation) effect by fuel. This method has supplied EGR gas to the fuel side instead of supply EGR gas to the intake gas side. The fuel has followed specific characteristics for the diesel combustion. When the fuel is injected into the chamber in low pressure, this CO2 gas is separated from the fuel spray. The distribution characteristics of the spray are improved and the improvement of the thermal efficiency by reduction heat loss in the combustion chamber wall, and reduce soot emissions by the lean combustion is expected. Furthermore, this CO2 gas decreases the flame temperature. Further, it is anticipated to reduce NOx emissions by the spray internal EGR effect.

Diesel Particulate filter (DPF) is installed as after treatment device of exhaust gas in diesel engine, and collects the Particulate Matter (PM). However, as the operation time of engine increases, PM is accumulated in the DPF, resulting in deterioration of PM collection efficiency and increasing in pressure loss. Therefore, Post injection has been attracted attention as DPF regeneration method for burning and removing PM in DPF. However, Post injection causes oil dilution when fuel is injected at the middle to late stage of expansion stroke. Oil dilution are concerned to deteriorate the sliding property of piston and the thermal efficiency. For this reason, it is necessary to elucidate the mechanism and the behavior that spray impinges lubricating oil film. Therefore, in this study, we aimed to construct model of Computational Fluid Dynamics (CFD) that predicts amount of oil dilution which is concern for post injection in diesel engine, with high accuracy.

The tire is one of the most important parts, which influence the noise, vibration, and harshness of the passenger cars. It is well known that effect of rotation influences tire vibration characteristics, and earlier studies presented formulas of tire vibration behavior. However, there are no studies of tire vibration including lateral vibration on effect of rotation. In this paper, we present new formulas of tire vibration on effect of rotation using a three-dimensional flexible ring model. The model consists of the cylindrical ring represents the tread and the springs represent the sidewall stiffness. The equation of motion of lateral, longitudinal, and radial vibration on the tread are derived based on the assumption of inextensional deformation. Many of the associated numerical parameters are identified from experimental tests.

n-Tridecane is a low boiling point component of gas oil, and has been used as a single-component fuel for diesel spray and combustion experiments. However, no reduced chemical kinetic mechanisms for n-tridecane have been presented for three-dimensional modeling. A detailed mechanism developed by KUCRS (Knowledge-basing Utilities for Complex Reaction Systems), contains 1493 chemical species and 3641 reactions. Reaction paths during ignition process for n-tridecane in air computed using the detailed mechanism, were analyzed with the equivalence ratio of 0.75 and the initial temperatures of 650 K, 850 K, and 1100 K, which are located in the cool-flame dominant, negative-temperature coefficient, and blue-flame dominant regions, respectively.

In a typical mechanical product such as an automobile or construction machinery, it is important to identify deformation modes, for which experiments and analyses can result in significant improvements. It is also important to consider how to improve the structure with high rigidity by using a technique such as the strain energy method in conventional design and development. However, the abovementioned method often generates conflicting results with regard to weight saving and cost reduction of development requirements. Transfer path analysis (TPA) using the finite element method (FEM) is an effective way to reduce noise and vibration in the automobile with respect to these issues. TPA can reveal the transfer path from the input to the response of the output point and the contribution of the path, and to efficiently consider improved responses.

Fuel design approach has been proposed as the control technique of spray and combustion processes in diesel engine to improve thermal efficiency and reduce exhaust emissions. In order to kwow if this approach is capable of controlling spray flame structure and interaction between the flame and a combustion chamber wall, the present study investigated ignition and flame characteristics of dual-component fuels, while varying mixing fraction, fuel temperature and ambient conditions. Those characteristics were evaluated through chemiluminescence photography and luminous flame photography. OH radical images and visible luminous flame images were analyzed to reveal flame shape aspect ratio and its fractal dimension.

In direct injection spark ignition (DISI), spray characteristics such as the penetration, spatial dispersion, droplet size distribution and the spray wall interaction process are extremely important to control the combustion process through the mixture formation process. Furthermore, the spray basic feature including the spatial and temporal changes is the key issue to reduce the Particulate Matter (PM) & HC emissions. In this study, we reveal both of the macroscopic and microscopic structures of the spray dynamics by Super High Spatial Resolution Photography (SHSRP). Furthermore, it is found that the simulated spray structure such as the penetration and droplet size distribution using Computational Fluid Dynamics (CFD) code is well consistent with the experimental results.

In order to reduce CO₂, Electric Vehicles (EV) and Hybrid Vehicles (HV) are effective. Those types of vehicles have powertrains from conventional vehicles. Those new powertrains drastically improve their efficiency from conventional vehicles keeping the same or superior power performance. On the other hand, those vehicles have an issue for thermal energy shortage during warming up process. The thermal energy is very large, and seriously affects the fuel economy for HV and the mileage for EV. In this paper, we propose VHDL-AMS multi-domain simulation technique for the estimation of the vehicle performance at the concept planning stage. The VHDL-AMS is IEEE and IEC standardized language, which supports not only multi-domain (physics) but also encryption. The common modeling language and encryption standard is indispensable for full-vehicle simulation.

Auto-ignition and combustion processes of dual-component fuel spray were numerically studied. A source code of SUPERTRAPP (developed by NIST), which is capable of predicting thermodynamic and transportation properties of pure fluids and fluid mixtures containing up to 20 components, was incorporated into KIVA3V to provide physical fuel properties and vapor-liquid equilibrium calculations. Low temperature oxidation reaction, which is of importance in ignition process of hydrocarbon fuels, as well as negative temperature coefficient behavior was taken into account using the multistep kinetics ignition prediction based on Shell model, while a global single-step mechanism was employed to account for high temperature oxidation reaction. Computational results with the present multi-component fuel model were validated by comparing with experimental data of spray combustion obtained in a constant volume vessel.

In this research, we aim at the construction of a steering cooperation-type front-wheel steering control system to reduce the rider's steering load by stabilizing the behavior of the motorcycle when turbulence in the direction of a roll occurs during low-speed driving. Finally, a front-wheel steering control system that considers cooperation with a rider's steering based on the experimental result is constructed, and the utility is verified by simulation.

This paper describes the relationship between the rider's evaluation of feeling of pulse and the seat vibration of the cruiser-type motorcycle. A simulated running condition was created to measure the seat vibration and engine speed. Next, the seat vibration was reproduced on the hydrodynamic shaker. Finally, we examined the influence of which order of rotational speed effects evaluation of feeling of pulse in a forced vibration test. As a result, it is known that 0.5th and 1st orders of seat vibration contribute to evaluation of feeling of pulse near 1,500 to 2,000 rpm of engine rotation.

It’ll be expected that tandem riders increase in the future. So, there is a need to improve the motorcycle stability of tandem riding from the perspectives of safety and comfort. In this research, we focus on tandem riding at low speed because the motorcycle especially becomes unstable. In order to improve the stability of a motorcycle after disturbance is input by the passenger’s posture change, we design a front wheel steer control system that assists the rider’s driving operation. And we simulate it. It is necessary to consider cooperation with the rider’s driving operation. In this study, as a means to consider the cooperative control of the man-machine system, the fuzzy logic was applied to this system.

The particulate matters (PM) containing in the exhaust gas through a CI engine affects strongly the human health. Thus, it is very significant to measure the mechanism of PM itself generation for actualization of a clean CI engine. On the standpoint mentioned above, the authors carried out the experiments of the characteristics of PM generated from a small high speed DI CI engine with a single cylinder. The variables were the equivalence ratio, the injection timing, the EGR rate and the sort of fuel. As a result, the effect of experimental condition on the distribution of PM is clear through experiments.

Three-dimensional large eddy simulation (LES) has been conducted for a diesel spray flame using KIVALES which is LES version of KIVA code. Modified TAB model, velocity interpolation model and rigid sphere model are used to improve the prediction of the fuel-mixture process in the diesel spray. Combustion is simulated using the Eddy-Dissipation model. CIP method was incorporated into the KIVALES in order to suppress the numerical instability on the combustible flow. The formation of soot and NO was simulated using Hiroyasu model and KIVA original model. Three different grid resolutions were used to examine the grid dependency. The result shows that the LES approach with 0.5 mm grid size is able to resolve the instantaneous spray with the intermittency in the spray periphery, the axi-symmetric shape and meandering flow after the end of injection as shown in the experimental results.

It is thought that the synthetic gas, including hydrogen and carbon monoxide, has a potential to be an alternative fuel for internal combustion engines, because a heating value of the synthetic gas is higher than one of hydrogen or natural gas. A purpose of this study is to acquire stable auto-ignition and combustion of the synthetic gas which is supposed to be applied into a direct-injection compression ignition engine. In this study, the effects of ambient gas temperatures and oxygen concentrations on auto-ignition characteristics of the synthetic gas with changing percentage of hydrogen (H2) or carbon monoxide (CO) concentrations in the synthetic gas. An electronically-controlled, hydraulically-actuated gas injector was used to control a precise injection timing and period of gaseous fuels, and the experiments were conducted in an optically accessible, constant-volume combustion chamber under simulated quiescent diesel engine conditions.

This study discussed the mechanism of the low speed judder for wave type brake disc developed newly for recent motorcycles. Wavy disc was examined to investigate the effect of wave configurations on the BTV (Brake Torque Variation) behavior. Torque amplitude in braking was compared with respect to the revolution order which represented the multiple number of the number of revolutions. To explain the mechanism at the mode showing largest BTV, the elastic deformation of the pad was analyzed by finite element method concerning geometrical nonlinearity with commercial code. This study found that most crucial BTV appeared on low speed judder was observed at the 3 rd peaks on the revolution order. Test data showed that this crucial BTV was related with the number of waves at the disc periphery, and caused by the indentation of the pad into notched part at disc periphery.