In this research, the influence of Ash deposition in the Diesel Particulate Filter on the pressure difference across the catalyst has been analytically investigatedby observing the configuration of real Ash deposition and the numerical simulation. Furthermore, from this calculation result, it is suggested that pressure loss can be predicted when Ash deposition density is known, and the importance of a model of Ash deposition mechanism that quantitatively predicts density was shown.

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In this study, fuel droplet of about 20μm diameter that is assumed to be in combustion chamber is injected by experimental apparatus. After that, droplet goes to high temperature atmosphere. We observed and experimentally considered that fuel droplet evaporation and self-explosion phenomenon. Heat flux was changed by initial velocity in this study. It was found that even if the heating rate is low, it shows self-explosion phenomenon in the diffusion flame when he distillation temperature of the fuel droplet decreases. Furthermore, the evaporation rate increased linearly as the initial velocity became faster, but it does not affect breakup diameter.

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Air management system for high boost and high exhaust gas recirculation (EGR) rate was assumed as a key technology for reduction of fuel consumption and exhaust emissions. The concept of air handling system has been proposed using relatively small turbocharger combined with late intake valve closing. Essence of the proposed concept is an improvement in the disadvantages of high boosting system. The basic ideas of the concept were constructed by simulation and improved fuel economy and emissions reduction were demonstrated using a multi cylinder diesel engine.

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The system we developed enables to detect knocking by sound signals even under a circumstance, where mechanical noises that continuously changing with driving conditions exist. The effective feature values are calculated with the spectrum analysis from sound data captured near the TDC with a microphone. Threshold values for detecting knocking are decided by online update anomaly detection techniques. Thereby realizing knocking detects system, which is resistant to change trend of background noises. The system is effective for detection and objective rating of knocking. It is useful for the monitoring of knocking on automatic operation.

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The clarification of knock phenomena is necessary for further improvement of the thermal efficiency of gasoline engines. In order to clarify the factor that influences knock intensity, the propagating flame and behavior of end gas on knock occurrence process were observed using a constant volume vessel in this study. In the experiments, strong pressure oscillation occurred after auto-ignition in thermal boundary layer by end-wall. Then, one-dimensional numerical simulations were carried out under several thermal boundary conditions in order to investigate the influences of thermal boundary layer on knock intensity. It was suggested that knock intensity was affected by thermal boundary layer.

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The deactivation model of Diesel Oxidation Catalyst (DOC) was investigated on HydroCarbon oxidation test under the low exhaust gas temperature by changing HC species and PGM loading amount. Based on the assumption that the activation energy was independent of the PGM amount, the whole reaction model could be identified considering adsorption, reaction and desorption on the activation site of catalyst. It was found that the influence of PGM loading amount was expressed as the increase of the frequency factor, and that this model suggested the unique mechanism of different reaction behavior in C₃H₆ and C₁₀H₂₂.

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This study models short circuits of spark channels and discharge blow-outs. In the short circuit model, spark channels are short-circuited between two arbitrary locations when the electric potential difference between the two locations exceeds a certain threshold. The threshold is varied as a function of distance between the two locations as well as the discharge current. In the discharge blow-out model, discharge blows out when discharge current fall below a certain threshold, which increases with spark channel length. Furthermore, this study suggests modifying the Kim et al.’s equation which predicts electrical resistance of spark channels.

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The submodels of spark channel short circuit and blow-out, which were described in the 1st report, were implemented into a spark ignition model. The short circuit, whose major factor is electric potential differences between two arbitrary locations, occurs in the early phase of the discharge period and the blow-out, whose major factor is discharge current, occurs in the latter phase of the discharge period respectively. The behavior of spark channel, current and voltage of the secondary circuit and the ignition limit by increase of EGR rate agreed with a measurement data of a spark ignition process in a chamber.

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We propose a new cylinder head gasket model for the precise prediction of cylinder deformation. The proposed model is based on the high-order deformation modes of cylinder head gasket with the material characteristics of rubber coating and metal plate. This improvement affects the shear behavior of the contact surface between cylinder head gasket and cylinder block. According to the comparison with experiment results, it is found that the proposed model increases the prediction accuracy of the frictional shear force and contact status of cylinder head gasket without matching parameters for experiment conditions. The proposed model provides a useful design method for cylinder head gasket and engine structure.

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A higher compression ratio is necessary for further thermal efficiency improvement of internal combustion engines. However, irregular combustion phenomena such as pre-ignition and knocking are critical issues. This paper reports a new combustion concept to overcome these issues using high pressure gasoline injection. Functional capability was evaluated with spray measurements in a constant volume vessel and the feasibility was confirmed.

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In the previous paper, a new combustion concept using high pressure gasoline injection was proposed and feasibilities were suggested. In this paper, combustion concept and performance validation were conducted with a high compression ratio single cylinder engine. As a result, high efficiency was achieved by avoiding irregular combustion, with rapid combustion and smoke reduction brought by high pressure injection and high-functioned combustion chamber.

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The goal of this paper is to enable more accurate investigation of the influence of wheel stiffness on driving stability, which has thus far relied mainly on heuristics. The experimental method used was as follows. Analysis used wheel specifications with differing stiffness, and proceeded in steps starting with the relationship between wheel stiffness and tire contact patch characteristics, then the relationship between wheel stiffness and tire dynamic performance, and lastly the relationship between wheel stiffness and driving stability. The factors and effects were clarified in each step. Analysis of the relationships between the wheel stiffness ratio and driving stability and reduction of wheel weight were investigated.

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Automobile interior is one of the most crucial factors for evaluating products’ value. During the evaluation, tactile cue must play an important role in deducing product’s quality, however, the regionality of customer’s tactile perception is in most cases neglected in previous studies. This study conducted sensory evaluation tests of door armrests in three countries, Japan, USA and Denmark, which are representatives of East Asia, North America and Europe, respectively. Eight samples of door armrests and 29 words expressing tactile sensations were used in the test. 167 participants in total participated in the evaluation test, 53 from Japan, 64 from USA and 50 from Denmark. As results of factor analysis, cluster analysis and multiple regression analysis, the following conclusion can be derived, i.e., although there is no significant difference in preference perception of door armrests, the tactile perception structures are different among three countries.

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The research discussed in this paper studied a method of quantifying the sound quality of combustion noise identified using a method of extracting the contribution of combustion noise from vehicle interior noise during acceleration in the time domain. Subjective evaluation tests using Scheffe’s paired comparison method were conducted, involving the presentation of multiple types of combustion noise to 14 NVH development experts via a headphone-playback system. Based on the results of subjective evaluation tests, fluctuation intensity, a psychoacoustic metric, was employed in the development of the dissonant combustion noise index (DCNI) as a new objective evaluative index for the sound quality of combustion noise. A new technique that couples the method of extraction of the contribution of combustion noise in the time domain with the new index DCNI was used to analyze the combustion noise of Japanese Kei small car models, and the results demonstrated that the technique is able to provide an accurate quantitative grasp of the relative sound quality of combustion noise.

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Previously the authors reported on a sound quality evaluation method using a dissonant combustion noise index (DCNI) that is a new objective index for the contribution of combustion noise separated from vehicle interior noise during acceleration in the time domain. The research in this paper investigates a method of applying the DCNI to combustion noise acquired in an engine acoustic test cell. Due to differences in structural response functions, the combustion noise in the engine acoustic test cell differs in its sound pressure level and frequency characteristics from the combustion noise in the vehicle interior. Consequently, the DCNI is not directly available for combustion noise in an engine acoustic test cell. Therefore, focusing on the sensitivity differences in the structural response functions of the vehicle and the engine unit, the authors created a pseudo vehicle body response filter (PBR filter) that provides acoustic simulation of a standard vehicle body's response sensitivity. The PBR filter can convert the combustion noise in the engine acoustic test cell into a simulated equivalent of combustion noise in the vehicle interior, and makes it possible to use the DCNI. The PBR filter and the DCNI were used for an actual evaluation of the combustion noise from a prototype engine, and the results successfully confirmed the validity of this method.

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From 2016 the outside noise regulation becomes severe. And from 2020 fuel efficiency standards will become strict too. However, it is extremely difficult to achieve both further weight reduction and higher performance of soundproofing properties. Therefore, we focused on the material itself of the fibrous porous material. In the development of soundproof materials, prediction method of the acoustic properties is important. The purpose of this study is to formulate the relationship between fibrous characteristic and Biot parameters. Therefore, we prepared 60 samples with different fiber diameter and bulk density and measured Biot parameters of them.

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The localized fire test provided in the Global Technical Regulation for Hydrogen Fuel Cell Vehicles gives two separate test methods: the ‘generic installation test – Method 1’ and the ‘specific vehicle installation test – Method 2’. Vehicle manufacturers are required to apply either of the two methods. Focused on Method 2, the present study was conducted to determine the characteristics and validity of Method 2. Test results under identical burner flame temperature conditions and the effects of cylinder protection covers made of different materials were compared between Method 1 and Method 2. The results indicated that, where the cylinder had no protection cover and the burner flame was regulated under identical propane gas flow rate conditions, Method 2 registered higher burner flame temperatures than did Method 1. However, when the burner flame temperatures were set identical, the cylinder’s surface temperature and the time of thermal pressure relief device (TPRD) activation were both found practically identical between the two methods. Where the cylinder was protected with a steel cover, Method 2 gave lower cylinder surface temperatures during the TPRD pre-activation period. Where a thermoplastic (polypropylene) protection cover was installed, under a localized fire the cover melted into pools and drips of burning liquid and spread fire to other areas of the cylinder, thus leading to an expedited activation of TPRD. Nevertheless, the advantage of expedited TPRD activation varies according to how and where fire pools are generated by a melting thermoplastic cover in relation to the propane burner, it is necessary to examine the melting and burning behaviors of flammable protective devices in real world fire situations.

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Typically, many features are utilized to detect pedestrian by using LIDAR. However, to implement a pedestrian detector based on SVM algorithm, it is necessary to manually determine the features and their parameters. In addition, there are a large number of combinations of parameters, and it is also necessary to change the parameters according to the variety of the performance of LIDAR. To overcome above problems, we proposed automatic selection of features by using Real AdaBoost which is a one of statistical learning techniques. In some pedestrian detection experiments, our proposal method was compare to previous method based on SVM.

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NIR spectroscopic method was applied for road surfaces in winter and the feasibility of real-time detection for the friction coefficient was reported on the previous study. In this paper, a real-time two-dimensional measurement method, polarized spectroscopic analysis, with an image from conventional CCD camera ready on board in current vehicle was tested. First of this study, methodology of spectral polarization measuring, “Fresnel equations” were applied and build the theoretical formulas for the tested road conditions. Furthermore, by the experimental analysis, the possibility to distinguish road conditions and estimate a road surface friction coefficient at vehicle forward are observed.

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The purpose of this study is to clarify the situation of accidents involving bicycles carrying children for accident prevention and damage mitigation. We performed two rear-end crash tests in order to understand the behavior of cyclists and children in the accidents. As a result, the value of HIC of the child dummy at the collision with the road surface was much higher than that at the collision with the hood. In addition, depending on the behavior of a child falling to the road surface, it was suggested that the seat belt could lower the risk of child’s head injury.

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In penetration phase of automated vehicle into market, adapting automated vehicle control to the driver’s individual driving style is assumed to contribute to feeling of safety and acceptability. In this study, we proposed and demonstrated a modeling method with a small number of parameters to adapt distance to preceding vehicle during automated vehicle control to the driver’s individual driving style. An experiment using a real vehicle on a proving ground showed the effectiveness of our method to increase the driver's feeling of safety and acceptability.

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In the right turn at intersection, driver’s eyes are directed to right traveling direction while monitoring oncoming vehicle. This situation is a dual task which requires appropriate attention allocation by central view and peripheral view. In this study, a performance test to measure this kind of attention allocation ability was proposed. Through an experiment with 18 participants, it was found that sum of response errors to visual stimulus may reflect the ability, especially in the highest level of task difficulty. As for reaction time to the visual stimulus, it correlated with the scale for independent and interdependent construal of self.

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The present study aims to clarify effect of display position to show message for take-over request on driver's response during automated driving at low speed. We conducted an experiment on a test track using 20 participants. The conditions of the experiment were designed to examine the take-over process of inattentive drivers engaged in an interaction with the secondary task at low speed. There were two take-over requested conditions which were system boundary condition and system failure condition. The on-board display using for the secondary task and the center display in the instrument cluster were used to show messages for the take-over request. The study found that the response time to take control during the automated driving using the on-board display and the central display was shorter than that using the central display only under both of take-over requested conditions. Also, the drivers took appropriate gaze reaction when the takeover request indicated on the on-board display rather than on the central display under both of take-over requested conditions. It is supposed that indicating the message of the take-over request on the display showing the secondary task might reduce the driver's response time and lead appropriate driver's gaze reaction during automated driving at low speed.

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The amount of air into IC engine’s cylinders is affected by the heat transfer at the intake system, which is changed by the development of thermal boundary layer, the opening and closing of intake valve, and so forth. Our previous study developed the empirical equation for the intake manifold model assuming as the cycle-averaged quasi-steady state heat transfer. On the other hand, the present study also improved the newly empirical equation with the quasi-steady state heat transfer for the intake manifold of the actual IC engine. Consequently, the Nusselt number used in the newly empirical equation was expressed by using the Reynolds number, the Gratez number and the Strouhal number, which represents the effects of the intake air gas flow rate, the development of thermal boundary layer and the engine speed, respectively. In addition, the outlet air temperature at the intake port was estimated with the accuracy of maximum error of 5.6%, which was improved in comparison with the results obtained from the Colburn equation.

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The research and development of the eco-car are advancing rapidly. On the other hand, only little information about merits to environment by the recycling of the car can be obtain. Particularly, the merits are not understood well when plastic parts are recycled. In this study, the LCA of the compact car was studied as a case study. The amount of CO₂generated in life cycle of a car was calculated. A lot amount of CO₂ generated by the combustion of fuel in traveling was estimated as compared with stage of car production. The reduction of CO₂ by mechanical recycling of ferrous metal and aluminum parts was a lot due to weight of parts. It is difficult to decrease CO₂ by thermal recovery using plastics waste. It had been found that a little CO₂ can be decreased by reduction of manufacturing of virgin plastics by mechanical recycling of plastics.

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Modeling that high stresses exist in the flange pipes of mufflers caused by the vibration of a moving vehicle or an operating machine, fatigue strengths of MIG outer, MIG inner and TIG inner peripheral side welded samples were defined through bending fatigue experiments. Factors affecting fatigue to failure, such as welding bead shapes, notch sizes and metallographic structures were identified through local stress measurements, FEM stress simulations, microscope observations and SEM-EDS composition analyses. Fatigue strengths decreased according to stress concentration factors in some cases but not in samples with different welding, and stress intensity factors were used for analyses.

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To clarify the mechanism in which a 0.1C-2Si-5wt%Mn fresh martensitic steel shows high strength and high ductility, the relationship between work hardening behavior and dislocation density change during tensile test using high intensity X-ray diffraction in synchrotron radiation in SPring-8. The increase in Mn content from 1.5 to 5% enables martensitic structure to increase dislocation density from 2.5x10¹⁵ to 4.4x10¹⁵mm/mm³, resulting in higher work hardening rate. The dislocation arrangement parameter obtained by the XRD result and TEM observation revealed that the addition of 5% Mn brought about retarding the formation of dislocation cell structure enable to increase dislocation density.

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In order to quantify the relationship between the meteorological environment and automobile interior part temperature, outdoor exposure tests were conducted in Yomitan village, Okinawa prefecture, for 5 months from August 1, 2016 to December 31, 2016. We were able to estimate the temperature history of interior part by data of total solar insolation and the lowest temperature and specific heat 1 / Ci inherent in the automobile. By using this method, it is possible to easily estimate the temperature history of the interior part exposed to the actual weather environment.

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Research on autonomous driving is vigorously progressing. In city areas, autonomous driving to destinations reduces driver’s load and enables efficient logistics. In this paper, decision making methods for the city autonomous driving are proposed, which consists of One Dimensional Situation Map (ODSM) and individual driving judgments for events. The ODSM is implemented as a series of event points (c.f. intersection, lane change, and merging) with driving decisions. Consequently, the autonomous vehicle can drive in complicated city areas with the simple ODSM. The proposed methods were implemented on a test vehicle and verified on the public road.

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One of the expected effects of the autonomous cars is that it can support the mobility for elder people. For example, it could be used as a driverless taxi for supporting mobility. This study investigates the contributing factors on intention of using driverless taxi using survey results of an autonomous cars ride test. Meanwhile, it also gives some insights into demonstration and implementation of a driverless taxi in future.

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The regulations for internal combustion vehicles, CO2 emission or NOx emission or noise and so on, are strengthened, .Therefore EV (electric vehicle)'s market is expanding. The amount of EV get more, the amount of electric get more and the impact for grid that are voltage fluctuation and frequency fluctuation is concerned. The short driving range is also problem for usability. It is important to inform driver not only SOC but possibility to arrive at destination without charge. So predicting to traffic condition is important. As the basic technology, the prediction the vehicles’ state that is drive or stay is important to solve two problems. In this research, Algorithm for predicting vehicle fleet's condition is developed. The data for study and test is obtained by person-trip survey conducted by Ministry of Land, Infrastructure and Transport. The location was divided into3 areas. And the state was stay or drive from an area to an area. The algorithm is based on left to right Markov-model. Future state probability is predicted using the latest observed state and state transition probability. As the result, prediction error is 3 % as parking. The prediction error of stay is less than the prediction error of drive. The frequency of stay is more than the frequency of drive, and robustness of stay for outliers is stronger. Therefore study data and test data are separated into week day and holiday, prediction error is about 1 %.

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