Although the motoring measurement method is generally used in comparison of engine friction losses, the condition of motoring engine is different from firing engine. Furthermore, in order to evaluate friction losses in each part of engine component, the firing measurement method in crank angle domain must be required. Therefore, the firing measurement method for total engine friction loss has been improved. This method is based on the fact that fluctuation of angular velocity in crankshaft system is related to indicated, brake and friction torque variation. Finally, this technique is applied to new diesel engine to confirm the reduction of friction losses.

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The 3.0L diesel engine friction loss was reduced by the piston ring tension reduction, the cylinder bore and the piston roughness reduction, the width reduction and the MoS2 coating of the crank bearings, the camshaft needle bearings. The dummy head machining prevented the worsening of the LOC and the blow-by gas by the piston ring tension reduction. The MoS2 shot peening that prevented the scuff by the low roughness cylinder bore and piston skirt was demonstrated for the first time. And the dimples that reduced the friction loss of the piston ring was demonstrated for the first time.

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This study focuses on the capability of 2-ethylhexyl caprate, laurate, and palmitate for diesel engine, of which pour points are -50 and lower, -32.5, and -2.5 degree Celsius respectively. All of them have excellent oxidative stability and high cetane number. The engine-bench test results show that 2-ethylhexyl laurate and palmitate produce short ignition delays compared to diesel fuel. Then, the rate of heat release due to the initial premixed combustion is suppressed. As the result, high brake thermal efficiency together with low combustion noise is achieved. Furthermore, laurate and palmitate give not only lower NOx emission, but also unburned gaseous emissions due to their short ignition delay.

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A study has been carried out to measure the particle mass, size, and number emissions from the latest direct injection gasoline passenger car equipped with idling reduction under urban driving cycles. The test vehicle emitted ultra-fine particles which have a concentration peak in 70 to 80 nm diameter. The particle mass emissions were lower than the Japanese PM limit for diesel passenger cars, however particle number emissions measured by EEPS(Engine Exhaust Particle Sizer) exceeded the EURO 5b and 6 limit for diesel passenger cars. The idling reduction was effective in CO₂ reduction; however it was shown that idling reduction enhances the particulate mass emission at the acceleration just after the engine start.

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It was shown that the trade-off of NOx and CO₂ emission from diesel engine fueled with DME is improved by setting an EGR system to Low Pressure Loop by past researches. In this paper, for the further low fuel consumption and emission of DME diesel engine, the influences of change of compression ratio, nozzle diameter and chamber shape on engine performance and emission characteristics were investigated.

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Recently many issues related to automotive engineering, such as the environment and energy problems have gained attention. These social-related issues are giving impetus to the adoption of urgent measures such as alternative fuels and new combustion techniques for the internal combustion engines. In this context, dimethyl ether is thought to be a potential alternative fuel, as it has lower overall pollutant emissions and better economy. The purposes of this paper are to examine the combustion properties of DME flames at elevated pressure up to 2.0MPa. The combustion properties of DME flames at elevated pressure up to 2.0MPa were examined to clarify the dynamic behavior of the effect of initial pressure corresponding to the practical engine condition. In addition, laminar burning velocities of DME-air mixtures were determined experimentally under the various pressures of 0.1MPa to 2.0MPa, employing spherically expanding flames diluted with Helium.

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The ignition timing of homogeneous charge compression ignition (HCCI) combustion engines is the important factor which should be controlled. In this study, the influences of the adding reaction intermediates to auto-ignition delay time were evaluated, by using a constant volume combustion simulation with detailed chemical reaction models of n-heptane. The lower the initial temperature becomes, the larger the effect of additives on the ignition promotion becomes. Therefore, it is appropriate to supply additives at the temperature which is dominated by low temperature oxidation reaction, in order to control the auto-ignition timing of HCCI combustion.

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This study aims at obtaining the after-injection strategy to reduce smoke emissions in a diesel engine, where after injection is employed in combination with pilot injection. The experiments were performed using a single-cylinder diesel engine under various conditions of pilot and after injection at a fixed load. The results show that small after-injection quantity with short interval offers reduced smoke emission. Larger pilot-injection quantity provides larger smoke reduction from the level in the case without after injection. The smoke-reduction effect is scarcely affected by pilot-injection timing in the case of a larger pilot-injection quantity. These tendencies are explained with attention to the interaction between main-spray flame and after-injection spray.

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In recent years, improving the engine fuel economy is strongly required. To enhance the engine thermal efficiency, it is important to improve the engine anti-knock quality and to decrease the engine cooling heat loss. To keep the compatibility with improving the anti-knock quality and reducing the cooling heat loss, it is important to analyze the thermal flow in the engine. This paper describes the thermal flow in the engine by using CAE and a single cylinder engine. It is shown that CAE can simulate engine thermal flow quantitatively. CAE can also demonstrate that cooling the upper part of the liner on exhaust side gives large effect on improving the anti-nock quality. This result is certified by conducting some tests with a single cylinder engine.

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The most important issues to introduce FCVs into the market are downsizing and cost reduction of the fuel cell stacks and its system components. From one of them, simplifying the hydrogen supplying system is highly expected. With the aim of eliminating the hydrogen recirculation system, transient mass transport analysis which are the CFD analysis with compressive low Re number flow field and a time-series measurement with mass spectroscopes to investigate the gas distribution in the anode flow channel have been implemented. This paper presents the time-varying gas concentration distribution.

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A measurement method for wireless power transfer (WPT) system with 0-ohm source impedance is shown. WPT systems are often designed by the BPF design theory and a vector network analyzer (VNA) is normally used for measurement. Here, some difficulty comes up for 0-ohm system that is common for high-efficient switching power sources. This paper describes the transmitted power and the transmission efficiency of 0-ohm system which are calculated by S parameters measured by VNA. The method is very simple and easy. The method is applicable not only for 0-ohm system, but also for other impedance systems.

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The vehicle fuel consumption improving is becoming important recently. Tire rolling resistance contribution to the fuel consumption is known to exceed 10%. However, the mechanism of rolling resistance related to tire alignment is not known clearly. This report discusses the rolling resistance generation mechanism by using FE tire model for chassis design.

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To achieve higher efficiency of HEVs, the optimization of each size and weight of power train components becomes more important for various vehicle segments because its system is more complex rather than conventional ICE vehicles. To solve this problem, models of a Diesel ICE, a motor and a battery are constructed for various sizes and weights. These models are used for optimization of hybridization of power train under NEDC mode conditions. The optimization algorithm is also used for optimization process. As a result, the optimum combination of the components for each vehicle segment is estimated.

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In this paper, the Component Mode Contribution Analysis is proposed, by which one can evaluate the mode contributions of the body and the suspension for a full vehicle interior noise. The basic idea of this technique is calculating the contribution of each component by using individual modal model of the body and the suspension based on the technique of Modal Differential Substructure (MDS). It is shown that this is an effective technique for the Eigenvalue Optimization and the Cascade Analysis, which are well used in automotive NVH problems.

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Research to reduce fuel consumption has become more important. In case of making more progress for fuel consumption by combustion improvement, it is better to employ combustion which occurs near the top dead centre (TDC) for better thermal efficiency. The combustion near the TDC, however, has a tendency of intensifying combustion noise. A study on an optimal cylinder pressure waveform with a multi-objective optimization simulation was undertaken in order to improve both fuel consumption and combustion noise simultaneously. This paper shows the simulation technique and results of a feasibility study of the optimal cylinder pressure waveform calculated by the simulation.

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Accurate prediction of occupant's head-neck motion during rear-end impacts is necessary to elucidate whiplash injury mechanism. This study applied a muscle control system using reinforcement learning, which is supposed to be a mathematical model of learning process in the basal ganglia, to a human head-neck finite element (FE) model and predicted muscle activity and motion of head-neck region during low speed rear-end impacts. Effects of muscle activity and individual variation of muscular physiological cross-sectional area for the head-neck responses were investigated.

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Abstract? In this paper, a dedicated on-board `sensor' utilizing wireless communication devices was developed for the collision avoidance around intersection. Four ZigBee wireless receivers are installed in the four corners of the driver's vehicle. Each receiver is shielded and has slightly directivity. These setting enable `sensor' to estimate the positions of the transmitters on pedestrians, bicycles, motor cycles, and vehicles based on a comparison of four signal strengths received from the four receivers. Since the estimation algorithm considers relative values obtained from the four wireless receivers, the detection results should not be affected by the transmission power. In addition to this, we improved our previous work considering the ground reflection model. On-board sensors utilizing vision, Laser Imaging Detection and Ranging (LIDAR), and radar cannot detect objects hidden by road facilities and other vehicles. Although infrastructure sensors for vehicle-to-infrastructure (V2I) cooperative systems can detect such hidden objects, they are substantially more expensive than on-board sensors. The on-board wireless `sensor' developed in this work would function as an alternative tool for collision avoidance around intersections.

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The relation between vehicle′s wiggly behavior and reaction time of the driver of the vehicle was analyzed for general drivers when they ran local streets like usually in the state of usual awakening level. Gas-pedal reaction time of a driver to brake lamp lighting of a leading vehicle was used as the reaction time. As a result, the wiggly behavior while a vehicle runs along a straight lane was statistically related to the reaction time of the driver of the vehicle. And, statistical relation between the mean log power in the frequency band of 0.2-0.8 Hz of each of lateral displacement, deviation of lateral displacement, and steering angle of a vehicle and the distribution of the reaction time was revealed.

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An estimation method for vehicle aerodynamic noise considering characteristic of acoustic near field and far field is suggested. Wave length of low frequency sound is so long that local pressure fluctuations which are called pseudo-sound are predominant over acoustic waves. Therefore low frequency aerodynamic noise inside the cabin is affected by pseudo-sound on a vehicle body surface. On the other hand, wave length of high frequency sound is shorter than that of low frequency one. Pseudo-sound attenuates and a vehicle body surface is excited by not only it but also acoustic waves.

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For the reduction of green house gas emission in transportation sector, an eco-driving has been promoted. To clarify the CO₂ reduction and the effects on NOx emissions by eco-driving, an on-road driving test using diesel freight vehicle equipped with the on-board measurement system has been conducted. This paper reports the analytical result about CO₂ reduction effects and NOx emission changes under each payload condition by eco-driving techniques, such as idling stop, early-shift-up and gentle acceleration.

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A practical detection system of engine load is required especially for a spark advance control system. We have successfully developed a system to estimate Indicated Mean Effective Pressure (hereafter, IMEP) by detecting the crankshaft angular velocity variation during one cycle of a four-stroke single-cylinder gasoline engine. This system has been commercially applied to the spark advance control system for small-displacement motorcycles. The system consists of the conventional hardware and the modified software. This paper clarifies the possibility of IMEP estimation using the crankshaft angular velocity variation based on the experiments and theoretical considerations.

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At interurban transportation, improvement of fuel economy of hybrid electric heavy-duty diesel vehicles, which assist drive-axle by using regeneration energy, is minimum, compared to heavy-duty diesel vehicles. One of the factors is that hybrid electric heavy-duty vehicles are not able to balance regeneration energy (input) and power energy (output) at high speed driving. The reason that the vehicles at high speed driving is not chance braking timing. In this research, we focus on the method used for the battery energy, and propose a new concept of hybrid electric system to efficiently utilize battery energy. That system consists of electrical booster for supercharging intake air into engine cylinder. We have confirmed the feasibility of the electric system of a new HEV concept by using the simulation I created.

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With the progress of sensors in terms of downsizing, accuracy, durability, and so on, measurement technology of characteristics of dynamic tire contact patch behavior has been developed in many ways. Understandings of those tire characteristics would be essential for those of vehicle behavior; however, detailed, accurate and reproducible contact force distribution measurement technology under severe rolling conditions could not be seen. Therefore, dynamic tire contact patch measurement and visualization system has been developed. Application of the measurement system for the development of the latest eco-tire is presented in this paper.

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By using FEM, the effects of cross sectional shape and material strength on torsional buckling behavior of thin walled square tubes were studied to establish a design scheme of high tensile strength steel with thin thickness for structural parts. Optimized cross sectional shape was clarified to improve torsional rigidity of thin-walled square tubes. Moreover, analytical result showed that not only cross sectional shape but also the strength of material affects the buckling moment, Mc of it. Particularly, controlling larger radius of curvature at ridge line of thin-walled square tube is needed when the strength of materials is increasing.

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As expanding the usage of adhesives in automotive bodies, non-destructive inspection techniques for them are increasingly required. The aim of this study is to evaluate adhesive regions with non-contact air-coupled ultrasonic technique. First, ultrasonic transmittance of steel plates was investigated theoretically and experimentally. As a result, transmitted waves at adhesive regions can be detected using oblique incidence and reception where the sensor angle is adjusted to the critical angle of A0 mode of Lamb waves. Secondly, images of the adhesive regions were obtained by scanning ultrasonic sensors and taking amplitude distributions of transmitted waves.

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Our previous study showed that images of adhesive regions between auto body steel sheets can be obtained using air-coupled ultrasonic sensors in oblique beam setting. This study introduced focus type sensors to improve spatial resolution and to reduce spaces required sensor arrangement. First, flat type and focus type sensors were compared in through transmission tests. Secondly, in the imaging tests of square holes with various sizes, it was confirmed that spatial resolution was improved using focus type sensors. Then, images of adhesive regions were obtained with high resolution by scanning the focus type sensors.

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As the number of ECUs in an automobile steadily increases, demand for increasing the number of ECUs connected to Controller Area Network (CAN) also rises significantly. However, the number of connectable ECUs in a linear passive star of CAN is restricted because of the ringing phenomenon in communication signals. In this paper, we propose a ringing restraining circuit activated on high level ringing voltages. As a result, we can expand the number of connectable ECUs in a linear passive star, which enables to construct low-cost communication networks by reducing the number of gateways.

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PCI (Premixed Compression Ignition) combustion is a potential breakthrough technique to simultaneously reduce NOx and particulate matter in engine exhaust emissions. In addition, it is advantageous for fuel consumption by igniting around a top dead center. Moreover, dual mode combustion concept that combined conventional diesel combustion and PCI combustion was proposed as a practical use means. Noise reduction and sound quality improvement technique when the combustion mode is switched depending on the engine operating condition in dual mode combustion concept were developed as a step toward the practical use of PCI combustion.

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The objective is to indicate driver's preview time to cope with the many kinds of driving situations. A number of studies have attempted to quantify the preview times, although study results are not consistent. We performed literature review about driver's preview times. Based on reviewing results, it is found that the minimum preview time was minimum 2 seconds, and appropriate preview time was 5 seconds. Average preview time was 3-4 seconds. It could be concluded that driving assisting system which is contributed to traffic safety should consider driver's preview time.

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An estimation model for CO₂ emissions volume, which includes a database of future improvements of technologies for fuel economy, has been developed. The database has information about improvement effects and cost for fuel consumption for each technology. Cost and effectiveness analysis using this model for two scenarios was carried out. In the results of scenario analysis, in the Technology Advanced Case, CO₂ emissions volume decreased to50% from 2008 to 2030 in the passenger car sector.

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