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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.

This study investigates if particulates from a GDI engine can be significantly suppressed by use of ultra-high injection pressures under 2 different engine conditions known to be associated with high particulate numbers (PN): warm-up and transients. Experiments were carried out in a single-cylinder GDI engine equipped with an endoscope connected to a high-speed camera to enable combustion visualization. To mimic the warming-up, the coolant temperature was varied between 20 °C and 90 °C. A Diesel injector with modified nozzle was used and the injection pressures were varied between 400 and 1500 bar. The results revealed that increasing the fuel injection pressure decreased engine out HC and PN under warming-up conditions. However, the coolant water temperature was the most dominant factor affecting the emissions. For coolant temperature of 20 °C, the use of 1500 bar fuel injection pressure in comparison to lower fuel pressures resulted in significantly lower PN.

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.

Continuous improvement of gasoline engine emissions performance is required to further protect the global environment and also the impact of emissions on a local level. During real world driving, transient engine operation and variation in fuel injection, airflow, and wall temperature are key factors to be controlled. Due to the limited opportunity for optimization of engine control, generation of a well-mixed fuel spray is necessary to create a suitable combustion environment to minimize emissions. Optimum spray performance achieves minimum surface wetting as well as promoting evaporation and diffusion if wetting occurs. Improvement in spray homogeneity is an important step to achieve this. Higher fuel pressure is initially considered to achieve improvements, as it is expected to improve mixture formation by reduction of wall wetting due to high atomization and lower penetration, as well as improvement in spray homogeneity.

According to the advance of engine control development, demands for direct sensing of physical quantity have been growing. Regarding pressure sensing, key properties for direct sensing are robustness against high temperature and pressure, and response time in addition to accuracy. In this work, a pressure sensor module with these key properties was developed. First of all, a piezoelectric device was selected as a suitable sensing principle for the required properties because of its thermally stable piezoelectric effect and potential for simple installation structure. Regarding robustness against temperature, the sensor module was designed to form thermal isolation layer with outer housing which is optimized according to its application. Regarding robustness against pressure and response time, breakage of the piezoelectric element is the main technical issue.

This paper describes new method for selecting optimal field points in Inverse-Numerical Acoustic analysis (INA), and its application to construction of a sound source model for diesel engines. INA identifies the surface vibration of a sound source by using acoustic transfer functions and actual sound pressures measured at field points located near the sound source. When measuring sound pressures with INA, it is necessary to determine the field point arrangement. Increased field points leads to longer test and analysis time. Therefore, guidelines for selecting the field point arrangement are needed to conduct INA efficiently. The authors focused on the standard deviations of distance between sound source elements and field points and proposed a new guideline for optimal field point selection in our past study. In that study, we verified the effectiveness of this guideline using a simple plate model.

The coming Diesel powertrains will remain as key technology in Europe to achieve the stringent 2025 CO2 emission targets. Especially for applications which are unlikely to be powered by pure EV technology like Light Duty vehicles and C/D segment vehicles which require a long driving range this is the case. To cope with these low CO2 targets the amount of electrification e.g. in form of 48V Belt-driven integrated Starter Generator (BSG) systems will increase. On the other hand the efficiency of the Diesel engine will increase which will result in lower exhaust gas temperatures resulting in a challenge to keep the required NOx reduction system efficiencies under Real Drive Emissions (RDE) driving conditions. In order to comply with the RDE legislation down to -7 °C ambient an efficient thermal management is one potential approach. Commonly utilized means to increase exhaust gas temperature are late injection and/or intake throttling, which enable sufficient NOx reduction efficiency.

In general, CFD analysis with porous media is precise enough to simulate airflow behavior in a heat exchanger core, placed in the vehicle. In a case when the airflow behavior is complex, however, the precision lowers according to our study. Therefore, we developed a new modeling method to keep high-precision and applied it to analysis of airflow in the vehicle. The concept is at first that the shape of tubes and the distance between the tubes are as the actual product so that the airflow with an oblique angle is to pass through a core. With this concept, airflow with an oblique angle hits the surface of tubes and passes through a core with changing the direction. Next, the concept is to reproduce the air pressure loss in actually-shaped fins, and therefore, we use a porous medium for the modeling of the fins instead of the product shape modeling to combine with the the tubes.

Tightening global emissions standards are driving automotive Original Equipment Manufacturer’s (OEM’s) to utilize Three Way Catalyst (TWC) aftertreatment systems that can perform with greater efficiency and greater measured control of Precious Group Metals (PGM) use. At the same time, TWC aftertreatment systems minimize exhaust system pressure drops. This study will determine the influence of catalyst substrate cell geometry on emission and PGM usage. Additionally, a study of lightoff and backpressure comparisons will be conducted. The two substrate configurations used are hex/750cpsi and square/750cpsi.

Emission regulations in many countries and regions around the world are becoming stricter in reaction to the increasing awareness of environment protections, and it has now become necessary to improve the performance of catalytic converters to achieve these goals. A catalytic converter is composed of a catalytically active material coated onto a ceramic honeycomb-structured substrate. Honeycomb substrates play the role of ensuring intimate contact between the exhaust gas and the catalyst within the substrate’s flow channels. In recent years, high-load test cycles have been introduced which require increased robustness to maintain low emissions during the wide range of load changes. Therefore, it is extremely important to increase the probability of contact between the exhaust gas and catalyst. To achieve this contact, several measures were considered such as increasing active sites or geometrical surface areas by utilizing substrates with higher cell densities or larger volumes.

Diesel common rail injectors are required to utilize a higher injection pressure and to achieve higher injection accuracy in order to meet increasingly severe emissions, less fuel consumption, and higher engine performance demand. In addition to those requirements, in conjunction with optimized nozzle geometry, a more rectangular injection rate and stable multiple injections with shorter intervals are required for further emissions and engine performance improvement by optimizing the combustion efficiency.

In automobiles, Integrated Starter Generators (ISGs) are important components since they ensure significant fuel economy improvements. With motors that operate at high voltage such as ISGs, it is important to accurately know partial discharge inception voltages (PDIVs) for the assured insulation reliability of the motors. However, the PDIVs vary due to various factors including the environment (temperature, atmospheric pressure and humidity), materials (water absorption and degradation) and voltage waveforms. Consequently, it is not easy either empirically or analytically to ascertain the PDIVs in a complex environment (involving, for example, high temperature, low atmospheric pressure and high humidity) in which many factors vary simultaneously, as with invehicle environments. As a well-known method, PDIVs can be analyzed in terms of two voltage values, which are the breakdown voltage of the air (called “Paschen curve”) and the shared voltage of the air layer.

Recently, diesel engine manufacturers have been improving the tolerance of fuel injection quantity and timing in response to the strengthening of emissions regulations and the introduction of various kinds of diesel fuels. This paper describes the Intelligent Accuracy Refinement Technology (i-ART) system, which has been developed as a way of achieving substantially improved tolerances. The i-ART system consists of a fuel pressure sensor installed in the injectors. It calculates the injection quantity and timing at high speed using a dedicated microcomputer designed for pressure waveform analysis. As the injector can directly measure the fuel injection pressure waveform for each injection, it can compensate the injection quantity and timing tolerance at any time. Toyota Motor Corporation has introduced this system in Brazilian market vehicles. In Brazil, the PROCONVE L6 emissions regulations will be introduced in 2012, and the market also uses various kinds of diesel fuels.

A hydraulic excavator cab is mounted on a viscous mount. When the weight of the cab is heavy, the neutral position is depressed. Besides, at a large load, the cab receives compressive repulsion power of oil thereby restricting its damping ability. In addition, it is difficult to obtain an arbitrary damping performance separately. To overcome these problems, which combines the shear force due to viscous fluid with elastic force due to air-spring a mount, was invented. The neutral position of composite mount is adjustable by air-spring according to the weight. And viscous oil is not sealed up. So, viscous oil can flow at a large load. Therefore, it may not experience the repulsion force of oil in spite of a large load. Moreover, the generated elastic force is adjustable according to change of pressure in the air spring, and the generated damping force is adjustable according to change of viscous fluid's viscosity or volume.

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.

It is very significant to take the intermediate products in diesel combustion for understanding the generation of exhaust emissions like SOF, dry soot and so on. The products generated in a constant volume combustion chamber were sampled by pricking a sheet of polyester film installed in the chamber to freeze the chemical reaction. The gas was analyzed by a gas chromatography. The fuel used was n-heptane. It is able to explain the generation of exhaust emissions by the experimental results. The other objective is to simulate the intermediate products. It is capable of explaining the relation between the simulated and experimental results.

The maximum liquid-phase penetration and vaporization behavior was investigated by using simultaneous measurement for mie-scattered light images and shadowgraph ones. The objective of this study was to analyze effect of variant parameters (injection pressure, ambient gas condition and fuel temperature) and fuel properties on vaporization behavior, and to investigate liquid phase penetration for the single- and multi-component fuels. The experiments were conducted in a constant-volume vessel with optical access. Fuel was injected into the vessel with electronically controlled common rail injector.

This work presents the ignition delay time characteristics of oxygenated fuel sprays under simulated diesel engine conditions. A constant volume combustion vessel is used for the experiments. The fuels used in the experiments were three oxygenated fuels: diethylene glycol dibutyl ether, diethylene glycol diethyl ether, and diethylene glycol dimethyl ether. JIS 2nd class gas oil was used as the reference fuel. The ambient gas temperature and oxygen concentration were ranging from 700 to 1100K and from 21 to 9%, respectively. The results show that the ignition delay of each oxygenated fuel tested in this experiments exhibits shorter than that of gas oil fuel for the wide range of ambient gas conditions. Also, NTC (negative temperature coefficient) behavior which appears under shock tube experiment for homogenous fuel-air mixture was observed on low ambient gas oxygen concentration for each fuel. And at the condition, the ignition behavior exhibits two-stage phase.

This paper provides new insights on the mechanism of the smokeless diesel combustion with oxygenated fuels, based on a combination of soot kinetic modeling and optical diagnostics. The chemical effects of fuel compositions, including aromatics - paraffins blend, neat oxygenated fuels and oxygenate additives, on sooting equivalence ratio ‘ϕ’ - temperature ‘T’ dependence were numerically examined using a detailed soot kinetic model. To better understand the physical factors affecting soot formation in oxygenated fuel sprays, the effects of injection pressure and ambient gas temperature on the flame lift-off length and relative soot concentration in oxygenated fuel jets were experimentally investigated. The computational results show that the leaner mixture side of soot formation peninsula on the ϕ - T map, rather than the lower temperature one, should be utilized to suppress the formation of PAHs and ultra-fine particles together with the large reduction in particulate mass.