Transactions of Society of Automotive Engineers of Japan
Online ISSN : 1883-0811
Print ISSN : 0287-8321
ISSN-L : 0287-8321
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Volume 46, Issue 2
Displaying 1-50 of 55 articles from this issue
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Technical Paper
  • Three-way Catalytic Performance of New Copper Catalyst for Precious Metals Reduction
    Kazuya Naito, Hiroshi Tsutsumi, Chihiro Matsuda, Yasutaka Nagao, ChunY ...
    2015 Volume 46 Issue 2 Pages 233-238
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.233
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    In order to reduce the amount of the precious metals for three way catalysts, we have investigated the catalysts utilizing 3d transition metals as alternative materials of precious metals, and have developed the Cu/Ce/Al2O3 catalyst with high catalytic activity. The new catalytic system was designed to suppress the deterioration according to the alloying Cu with precious metals, and to use effectively catalytic activity and the oxygen storage capacity of the Cu catalyst. The developed catalytic system containing the Cu catalyst with the amount of precious metals by 50% after the engine aging was able to achieve the J-SULEV standard.
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  • Development of Reduced PGM Three-Way Catalysts Enhanced NOx Purifying Activity
    Masahide Miura, Yuki Aoki, Nobusuke Kabashima, Takahiko Fujiwara, Tosh ...
    2015 Volume 46 Issue 2 Pages 239-244
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.239
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    In response to the growing awareness for environmental protection, automobile emissions regulations are gradually becoming more stringent all over the world. Moreover, the amount of precious metals used for automobile catalysts is required to decrease in order to lower the consumption of natural resources. As a consequence, further improvements to catalysts which contribute to a decrease in the amount of precious metals used while satisfying emission regulations are greatly needed. In this report, with the application of nanoparticle rhodium (Rh) clusters along with a high thermal stabilized pyrochlore-ceria/zirconia (CZ) catalyst, high performance three-way catalyst has been developed. Moreover, a zone coat strategy has been developed which improves cold start catalytic performance.
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Research Paper
  • The Improvements of Combustion and Emission from Hydrogen / Diesel Dual Fuel Engine
    Yasumasa Suzuki, Taku Tsujimura
    2015 Volume 46 Issue 2 Pages 245-251
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.245
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    Because hydrogen can be produced by renewable electricity and the combustion products from hydrogen mixture don’t include carbon monoxide or dioxide and unburned hydrocarbon components, we applied hydrogen to diesel dual fuel (DDF) engine and validated the method to improve combustion performance. H2 DDF operation could improve CO2, CO, THC and smoke emission that includes carbon without degradation of thermal efficiency, however, NOx emission gets worse than conventional diesel combustion. In addition, the operation was restricted by abnormal combustion occurred under high load and H2 ratio condition. For the reduction of NOx emission, combustion with advanced diesel fuel injection timing and EGR were effective methods. On the other hand, it is supposed that several percent of input energy was lost by unburned hydrogen remaining in the center of cavity and squish area and discharged from H2 DDF engine.
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  • Effect of Compression Ratio on the DME-HCCI Combustion in a 2-Stroke Spark-Ignition Engine
    Yuta Nagamine, Yuto Imada, Takuya Sakurai, C. González Palencica Juan, ...
    2015 Volume 46 Issue 2 Pages 253-258
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.253
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    In 2-stroke engines, intake or exhaust throttling is available to realize HCCI combustion due to the effect of the intemal EGR, Which gives another benefit of reduction in short-circuiting of the intake charge. DME (Di-methyl ether) having a high auto-ignition capability was applied to a 2-stroke engine, and its combustion characteristics, especially the effect of the compression ratio, the intake throttle opening, and the engine speed on the engine performance, were investigated. With the increase in the compression ratio and the intake throttle opening, the operation range of the engine shifts to leaner side because of the increase in the in-cylinder pressure and temperature. The BMEP decreases due to the decrease in the input heat, and the BSFC is determined by the balance of several parameters.
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  • Numerical Analysis of Air-Hydrogen Mixture Flow in Rectangular Indoor Space with Ventilators
    Hitoshi Sugiyama, Keita Takahashi, Naoto Kato, Atsuhiko Terada, Yu Kam ...
    2015 Volume 46 Issue 2 Pages 259-264
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.259
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    Numerical analysis has been performed for vertical buoyant flow of air-hydrogen mixture in rectangular indoor space with ventilators. The unsteady and laminar flow has been calculated by using the coupled conservation equations of hydrogen and momentum. Calculated results are compared with the experiment data of hydrogen concentration and velocity profile in order to confirm the validity of the presented numerical method and clarify the mechanism of hydrogen dispersion. Although agreement is certainly not perfect in all detail, the main features are reasonably reproduced. Adding to this, calculated results suggest that hydrogen concentration depends on Froude number.
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  • Development of EGR Reforming Catalyst for Gasoline Engine with Fuel Reformer
    Maki Hoshino, Takao Izumi, Hiroshi Akama, Masayuki Zaima, Koji Hiraya, ...
    2015 Volume 46 Issue 2 Pages 265-270
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.265
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    Stability of high EGR combustion is improved by the addition of hydrogen. So, we developed "EGR reforming catalyst" which produces hydrogen rich gas from fuel by using heat and water vapor of exhaust in order to realize on-board hydrogen generation. It was found that main issue to realize EGR reforming catalyst was a suppression of catalyst deterioration under the exhaust gas condition. We found out that water activation of the catalyst decreased with carbon deposition on the catalyst surface due to sulfur compounds adsorption. Catalyst degradation was inhibited by the improvement of water activation of the catalyst using rare earth component.
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  • A Study on Reduction of Heat Loss by Optimizing Combustion Chamber Shape
    Keita Arato, Teruyuki Takashima
    2015 Volume 46 Issue 2 Pages 271-276
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.271
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    The combustion chamber shape was optimized using three dimensional CFD simulations to reduce heat loss for a diesel engine with a high compression ratio. The resulting shallow dish-like combustion chamber showed potential for heat loss reduction with a better combustion state. In this optimized system, a portion of the fuel spray remained at the center of the combustion chamber because of wall impingement. The lower half of the fuel spray developed along the chamber wall. Furthermore, experiments using a single-cylinder engine were performed. The optimized chamber improved fuel consumption compared with its shallow dish-type counterpart. The thermal balance analysis revealed that heat loss from the cylinder decreased.
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Technical Paper
Research Paper
  • The Effects of Ignition Environments and Discharge Waveform Characteristics on Spark Channel Formation
    Taisuke Shiraishi, Atsushi Teraji, Yasuo Moriyoshi
    2015 Volume 46 Issue 2 Pages 283-288
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.283
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    In terms of the shift on the higher power side of the operating point by downsizing and improvement of real world fuel consumption, the improvement of ignitability is increasingly expected in the wide operating range also including high load and high engine speed region. In this study, the effects of gas pressure and gas flow near the spark gap at ignition timing, and discharge waveform characteristics on spark channel formation have been analyzed by using the constant volume chamber and the single cylinder engine, and the relation between spark restrike process and spark channel length was considered.
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  • Oil Going-up Mechanistic Analysis for Lube Oil Consumption Stabilization
    Hideshi Hitosugi, Fumihiro Nakada, Noritaka Yoshikawa
    2015 Volume 46 Issue 2 Pages 289-294
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.289
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    In order to realize stable oil consumption to the engine mode of operation in a market, the mechanism in a broad operating range needs to be grasped. Various evaluations of the piston ring motion, piston land pressure, and visualization in the operation range of a slowdown, a low speed, and high-speed fixed load were carried out. About visualization evaluation, it carried out drawing oil film distribution from image analysis. Examination and prediction of the oil action were performed for how it results in oil consumption generating.
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Technical Paper
  • Study of Ammonia Storage and Delivery Methods for SCR System
    Teruaki Kondoh, Kiyomi Kawamura, Matsuei Ueda, Susumu Nagano, Makoto K ...
    2015 Volume 46 Issue 2 Pages 295-300
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.295
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    The purpose of this study is to evaluate two methods of directly supplying ammonia for a selective catalytic reduction (SCR) deNOx system of a diesel engine. Unlike urea-SCR, direct ammonia supply methods for SCR enable NOx reduction in low temperature ranges. One supply method uses an ammonia salt called ammonia carbamate. This method generates large amounts of ammonia, but requires an apparatus temperature higher than 80°C to avoid re-precipitation of the ammonia carbamate. In contrast, a method utilizing an ammonia storage material is more compact than liquid urea and re-precipitation does not occur.
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Research Paper
  • Measurement of Fuel Injection Rate by LDA Flow Rate Meter and Spray Characteristics
    Shunsuke Kikuchi, Tetsuji Koyama, Kouhei Edure, Hisanobu Kawashima, Ts ...
    2015 Volume 46 Issue 2 Pages 301-306
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.301
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    It is necessary to clarify spray characteristics for improvement combustion efficiency. The author's group has been developed LDA flow rate meter based on Laser Doppler Anemometer (LDA) for the fuel injection rate measurement. The paper introduces the study of a flow rate measurement by LDA flow meter, Bosch type injection rate meter and of a visualization by high-speed camera. The fuel injection rate is measured with various fuel pressures and injection durations. It is clarified that the reflection pressure wave measured LDA flow rate meter does not affect spray characteristics.
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  • Diesel Combustion Characteristics of Coconut Oil Butyl Ester with Butanol
    Akira Itakura, Kenta Koide, Takeshi Otaka, Eiji Kinoshita, Yasufumi Yo ...
    2015 Volume 46 Issue 2 Pages 307-312
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.307
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    In order to improve the pour point and the smoke emission of coconut oil biodiesel, coconut oil butyl ester, trans-esterified from 1-butanol and coconut oil, was mixed with 1-butanol, and the fuel properties and the combustion characteristics and exhaust emissions of the blend fuel were investigated using a single cylinder DI diesel engine. From the experimental results, the pour point of coconut oil butyl ester was lower than that of coconut oil methyl ester, and when the 1-butanol content of the blend fuel increased, the pour point became lower and the smoke emission decreased.
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  • Numerical Simulation of Trapping Process in Hexagonal Diesel Particulate Filters
    Maki Nakamura, Katsunori Hanamura, Takumi Shibuta, Hajime Yoshino, Ken ...
    2015 Volume 46 Issue 2 Pages 313-317
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.313
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    The process of soot trapping in a hexagonal cell geometry diesel particulate filters (HEX DPF) in surface pores filtration made of aluminum titanium oxide were investigated through a simple analysis based on Darcy’s law through the wall and deposited soot layer. In this study, we focused on the trapping process of the HEX DPF cell in surface pores filtration by Numerical Simulation. The HEX DPF had two types of flow: one was a flow through a wall between inlet and outlet channels (inlet/outlet wall flow), and the other was a flow which was introduced into a wall between inlet and inlet channels, and was turned toward the direction parallel to the wall, and finally exited into the outlet channel (bypass flow). As a result, the process of soot trapping in surface pores filtration was shown by numerical simulation. It was possible to express the transition process from surface pores filtration to cake filtration.
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Technical Paper
  • Measurement Technique of Exhaust Valve Temperature
    Nobuyuki Tanaka, Kiyoshi Iwade, Akihiko Kawata
    2015 Volume 46 Issue 2 Pages 319-324
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.319
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    Thermal load caused by engine combustion is one of the important issues for the engines such as high-boosted downsized engines and engines with high compression ratio. In particular, it is necessary to maintain the reliability and durability of exhaust valves which are subject to the biggest thermal impact. For this reason, sodium filled hollow valves are utilized in preference to solid valves in order to decrease the exhaust valve temperature. The most common method for detecting the valve temperature is to estimate the temperature by measuring hardness on valve surface (Hardness test). However, the hardness test is only applicable to the condition up to 800°C. Therefore, this paper presents new techniques for measuring the temperature for sodium-filled valve using infrared thermography and thermocouple as an alternative hardness test. The authors also examined the valve temperatures at a variety of engine speeds and cooling of the sodium-filled valve during engine operation.
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Research Paper
  • Development of CFDMethod for Spray Shape Estimation
    Chikara Dodate, Motonari Yarino, Masato Kawauchi, Rio Shimizu
    2015 Volume 46 Issue 2 Pages 325-329
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.325
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    Although many CFD analyses have been applied for the prediction of spray behavior in the direct-injection gasoline engines, a priori estimation of the spray characteristics including the penetration length and the Sauter mean diameter is difficult, and the empirical determination of the model parameters are usually necessary. The purpose of this study is to develop a CFD modeling scheme to estimate the engine performance fromthe nozzle characteristics for the front-end loading design of injector nozzles.We have developed a method to predict the spray shapes by applying the LES turbulence model for the internal flow of the nozzles. The method has been applied to estimate the engine performance in conjunction with spray models.
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Technical Paper
  • A Study on Effects of Wear and Deformation of Nozzle Seat of Diesel Fuel Injector
    Kou Satake, Jeonggee Son, Equo Kobayashi, Masabumi Masuko, Susumu Sato ...
    2015 Volume 46 Issue 2 Pages 331-336
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.331
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    Wear of nozzle’s body seat of diesel fuel injector, which is caused by the collision of needle on the body seat in a nozzle, affects fuel spray behaviors and injection characteristics. In this study, in recent years, the nozzle DLC coated needle in the DLC that came to be used as wear protection, the wear test conducted, it was subjected to various analyzes. A result of the FE-SEM observation for the wear surface of the body seat, in the DLC nozzle, corrosive wear scar observed on the Non-DLC conventional nozzle is not observed and machine wear scar remained. In addition, the result of hardness measurements on the wear portion below the surface, the hardness was increased. Therefore, it was likely that rather than corrosion wear was a major cause of wear of the Non-DLC nozzle, plastic deformation is the main cause in the DLC nozzle.
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Research Paper
  • Investigation of In-Cylinder Soot Distribution in a DISI Engine
    Takeshi Ueki, Eiji Murase
    2015 Volume 46 Issue 2 Pages 337-342
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.337
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    In order to reduce Particulate Matter (PM) emitted from Direct Injection Spark Ignition (DISI) engine, the key is to figure out the soot formation process in the cylinder in addition to the exhaust gas measurement. In this study, the distribution of soot diameter and soot number density in the cylinder was investigated by Time-Resolved Laser Induced Incandescence (TR-LII) technique with a glass cylinder engine. At fast idle, high density of soot was observed at the side of piston lip at the around bottom dead center of expansion stroke. And, on this timing, the soot shifted to large size.
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  • The Influence of Oxygen Concentration on the Ignition Characteristics of Ethanol – PRF Blends
    Ryosuke Okada, Naozumi Isobe, Mitsuru Konno, Kotaro Tanaka
    2015 Volume 46 Issue 2 Pages 343-348
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.343
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    Experimental ignition delays of ethanol, PRF 90 and ethanol – PRF 90 blend fuels were measured using a rapid compression machine at an equivalence ratio of 1.0 with oxygen concentrations 8～16% in nitrogen, and argon, in the temperature range 862～911 K and pressure range 2.52～2.73 MPa. The measured ignition delays were compared with the numerical predictions. The ignition delays for ethanol were found to decrease with an increase in the temperature and the simulated ignition delays using the detailed PRF kinetic model constructed by KUCRS, which included the ethanol oxidation mechanism, were in reasonable agreement with those obtained from experiments. The addition of ethanol to PRF 90 increased the ignition delays with oxygen concentrations 12, 16%, while the ignition delays were almost kept constant with oxygen concentration 8%. We found that the oxygen concentration had influence on the ignition characteristics of ethanol-PRF blend fuels.
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  • Study on the Ignition and Flame Structure of Diesel Combustion by Using Dual-component Fuels
    Masashi Ajioka, Tomoyuki Mukayama, Satoshi Miyata, Yu Kuwahara, Yoshim ...
    2015 Volume 46 Issue 2 Pages 349-354
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.349
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    The authors have proposed the combustion control by using multi-component fuel spray. In this report, spray and ignition characteristics and flame structure were investigated for various two-component fuels. Various low boiling point components were mixed into high boiling point component to change vaporization and ignition characteristics of mixed fuel spray. In this step, the control of flame structure prevents the flame contacting with the chamber wall, and reduces heat loss. The optical measurements were carried out under the constant volume vessel. As an experimental result, physical and chemical characteristics of low boiling point fuel contained in mixed fuel affects with the ignition characteristics and flame structure.
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Technical Paper
  • Prediction Method of Outer Ring Creep Phenomenon of Ball Bearing under Bearing Load
    Takayuki Teramoto, Yutaka Sato
    2015 Volume 46 Issue 2 Pages 355-360
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.355
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    In this paper, prediction method of outer ring creep phenomenon of ball bearing under bearing load was studied. The mechanism of creep was verified by the 2D-analysis model. As a result, the elliptic motion on the outer ring surface was observed under bearing load with the rotation of bearing element. We established the 3D-analysis model to be predictable of a relative creep speed. The contribution of the design parameters for the creep speed was analyzed by using this model and the design of experiment. As a result, the contributions in bearing are large, and they in the casing are small.
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Research Paper
  • Development of Electrocatalysts for Platinum-free Liquid-feed Fuel Cells
    Hirofumi Kishi, Tomokazu Sakamoto, Koichiro Asazawa, Hirohisa Tanaka, ...
    2015 Volume 46 Issue 2 Pages 361-366
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.361
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    The performance of fuel cells depends on catalytic activity strongly. The interaction between catalytic activity and iron chelate (Fe-N-C) structure applying Rotating Ring-Disk Electrode (RRDE), evaluation of MEA performance, Hard X-ray Photoelectron Spectroscopy (HAXPES) and in-situ X-ray Absorption Spectroscopy (XAS). From the results of the investigations, it is confirmed that Fe is one of the active sites and find that the pyrrolic nitrogen structure enhances the catalytic activity.
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Technical Paper
  • Performance Evaluation of Short Range Frequent Charging Electric Bus (First Report)
    - Detailed Analysis of Inductive Charging Performance over Long-term Operation of Development Bus -
    Yushi Kamiya, Shunsuke Takahashi, Yasuhiro Daisho
    2015 Volume 46 Issue 2 Pages 367-372
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.367
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    A long-term operation test of a specially developed electric bus has been performed as part of a project organized by the Japanese Ministry of the Environment. The following information related to the inductive power supply (IPS) system was obtained. (1) One practical issue of the IPS system is misalignment between the transmitting coil and receiving coil when the vehicle is parked outside the optimum position. After measuring and evaluating this issue over a period of five months using the developed mini bus, it was found that misalignment tended to be greater in the longitudinal direction than the lateral direction. After the driver became fully accustomed to parking the mini bus, the evaluation found that the maximum misalignment was approximately 6.5 cm. (2) The degree of misalignment measured in the test had virtually no adverse effect on the efficiency of the adopted IPS system (86% when the coils are aligned directly opposite each other). (3) The feasibility of moderating the system performance was examined, principally to help reduce costs. Specifically, a new system design theory was proposed that moderated the design requirement for the reduction in the coupling coefficient that occurs when misalignment increases. After studying and adopting the proposed method, it was found that, even with a large moderation in coupling coefficient performance, it could be possible to realize a system with only a comparatively small drop in efficiency.
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  • Performance Evaluation of Short Range Frequent Charging Electric Bus (Second Report)
    - Detailed Analysis of Battery Deterioration over Long-term Operation of Development Bus -
    Koichiro Taniguchi, Yushi Kamiya, Yasuhiro Daisho
    2015 Volume 46 Issue 2 Pages 373-378
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.373
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    A long-term operation test of a specially developed electric bus has been performed as part of a project organized by the Japanese Ministry of the Environment. The following battery-related information was obtained. (1) The bus was driven for 48,714 km over 1,872 days and charged 4,958 times. As a result, the capacity of the on-board lithium-ion batteries (LIB) fell by approximately 25% and the internal resistance increased by approximately 50%. An evaluation method was proposed and adopted that estimated the capacity and internal resistance from easily obtainable terminal voltage and current data without removing the battery and performing detailed measurements. (2) Various measures were proposed and adopted to extend the battery lifetime. These included rotating the batteries between installation positions under different temperature environments, and adopting a battery-friendly seasonally variable charging rate method that reduces the charging power in seasons with lower power consumption. Simulations predicted that these measures have the potential to increase capacity retention by several % over 10 years from battery manufacture.
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Material
Research Paper
  • A Study on Change of Roll Natural Frequency
    Hideki Sakai
    2015 Volume 46 Issue 2 Pages 385-391
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.385
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    As a vehicle speed increases, roll natural frequency modes changes from that around its roll axis to that around its center of gravity of its body. To understand this phenomenon, the illustrated method for the change of roll natural frequency is proposed. Further a characteristic equation is considered and the combination of four kinds of design parameters which determine roll character frequency is found out. Parameter study was performed about the influence which the combination of those parameters has on roll natural frequency. As a result, the change of roll character frequency was understood.
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  • Influence of Wheel Stiffness on Vehicle Dynamic Performance
    Atsushi Hirano
    2015 Volume 46 Issue 2 Pages 393-398
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.393
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    The purpose of this study was to clarify the factors affecting how vehicle dynamic performance changes due to changes in wheel stiffness. First, actual vehicle dynamic performance tests were conducted to compare the influence of wheel stiffness on vehicle dynamic performance. The results confirmed that wheel disk stiffness and wheel rim stiffness influence actual vehicle performance differently. Tests were also conducted to investigate the relationship between wheel stiffness and the tire contact patch characteristics, and these results confirmed that wheel stiffness greatly influences the tire contact patch characteristics. Furthermore, it was also confirmed that appropriate values and threshold values exist for wheel stiffness.
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Technical Paper
Research Paper
  • Study on Combustion Chamber Resonance with a View to Improving Diesel Engine Sound Quality
    Hisashi Ozawa, Kenro Nakashima
    2015 Volume 46 Issue 2 Pages 425-430
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.425
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    Multi-objective optimization simulation to improve combustion noise, fuel consumption and exhaust emission was proposed. The simulation verified sound level improvement, however improvement of the combustion sound quality remained an issue. To improve diesel engine sound quality induced by combustion, investigations for a combustion chamber resonance was carried out. As a result, an acoustic characteristic of actual combustion chamber was acknowledged with an acoustic excitation test for in-cylinder and a pressure distribution measurement under operating condition. This report shows the results following the investigation focusing on the relationship between the combustion process and the resonance phenomenon.
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Material
Research Paper
  • Development of Steering Control System Based on Optical Flow Model
    Hiroshi Inou, Takanori Fukao, Seiji Totsuka, Yuki Okafuji
    2015 Volume 46 Issue 2 Pages 443-448
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.443
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    An expert driver can track the line precisely and gives better feeling of confidence． In our previous works, it was indicated that an expert driver uses optical flow information while driving, and we constructed a driver model focused on optical flow． Applying this optical flow model to automatic steering systems, a human-oriented system might be able to be developed． In this paper, we propose a nonlinear controller to apply the optical flow model to a vehicle control system． We implement the nonlinear controller to a vehicle control system, and in-vehicle researches are performed． Then, the experimental results are also presented to confirm the proposed controller works well．
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  • Effect Evaluation of Vehicle-Infrastructure Cooperative Right-Turn Collision Prevention System
    Shunsuke Nakamura, Hideaki Suganuma, Kazunori Kikuchi, Ryohei Homma
    2015 Volume 46 Issue 2 Pages 449-454
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.449
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    Right-turn accidents have occurred most often in the signalized intersection accidents. For preventing these right-turn accidents, we are working on research and development of a right-turn collision prevention system using the 700MHz band infrastructure-to-vehicle communication. In order to put into practical use the system, the effect evaluation is important. Therefore, we carried out a 101-person field operation test, and analyzed the obtained data, and quantified the effect of the system. In this paper, we will report about evaluation method we've considered for quantification.
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  • Cyclist Head Protection with Helmet in Impact against A-pillar
    Daisuke Ito, Keiji Oida, Goich Kobayashi, Koji Mizuno, Ryoich Yoshida
    2015 Volume 46 Issue 2 Pages 455-460
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.455
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    The head protection with cyclist helmets in impacts against the A-pillar was investigated from experiments and finite element (FE) analyses. In the A-pillar impact tests at 35 km/h, the HIC was above the injury acceptance level even with helmet. The FE simulations of the headform impacts indicated that the helmet liner deformed locally, whereas the A-pillar deformation was small. In the FE analysis of a human head model with a helmet, the skull fracture did not occur but the brain strain was large. From a simple model of the head acceleration, the helmet liner characteristics has a little effect on the HIC at high velocity impacts.
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Technical Paper
  • A Round Robin Test of Piezoresistive Shock Accelerometers between Shock and Centrifuge Calibrations
    Hideaki Nozato, Akihiro Oota, Wataru Kokuyama, Sakae Chiba, Masao Shim ...
    2015 Volume 46 Issue 2 Pages 461-466
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.461
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    A round robin test of piezoresistive accelerometers was carried out to confirm a consistency between shock and centrifuge calibrations among five participants; AIST, KYOWA, TTDC, JARI and NICS. AIST evaluated the accelerometers using shock calibration system in compliance with ISO 16063-13, and the shock calibration included various frequency components. On the other hand, the others evaluated them using centrifuge calibration system in compliance with ISO 5347-7, and the centrifuge calibration based on DC (direct current) measurement. Finally, the shock and centrifuge calibrations were implemented from 1000 m/s2 to 5000 m/s2, and the consistency using Z scores with the standard deviation of 0.9 % was satisfied among five participants.
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Research Paper
  • Driving Lane Evaluation Using Camera and Map Data
    Masato Imai, Masao Sakata
    2015 Volume 46 Issue 2 Pages 467-472
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.467
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    Identifying the vehicle’s position on the multi-lane roads is necessary for the route guidance system. The basic method to figure out the running lane is to detect the lane change behavior by using cameras. When the vehicle runs on the roads with unclear lane markings, a yaw rate sensor is useful to detect the lane change maneuver. But through the curve, it is difficult for the system to distinguish turning maneuver and lane-change maneuver only from the yaw rate sensor's signal. To distinguish those two maneuvers, we used the radius of road curvature from the map data additionally.
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  • Headway Estimation of Platooned Vehicles by Dual Filter Integrated with Car-Following Model
    Hironori Suzuki, Norikazu Ikoma, Takashi Nakatsuji
    2015 Volume 46 Issue 2 Pages 473-478
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.473
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    This paper applies a dual Unscented Kalman filter (DUKF) and a dual particle filter (DPF) for estimating the headway distance of vehicles traveling in a longitudinal platoon. Assuming that prior knowledge on the car-following model parameter is different from what is observed in a real car-following, DUKF and DPF attempt to estimate the headway by measuring the acceleration rate and velocity of all vehicles in the platoon. Numerical analysis showed that DUKF and DPF estimated the headway accurately with a satisfactorily level of estimation precision.
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Technical Paper
  • Curb Detection Based on Disparity Gradients and Template Matching
    Kiyosumi Kidono, Hiroyuki Ishida, Yoshikatsu Kimura, Takashi Naito, To ...
    2015 Volume 46 Issue 2 Pages 479-484
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.479
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    Road boundary detection on the roads without lane markings is one of the key technologies for advanced driver assistance systems. In particular, curb boundaries are important because curbs mean the physical boundary for the vehicle. This paper presents a method of detecting the curb boundary using an on-board stereo camera which can provide dense depth maps. The proposed method utilizes both the 3D road structure and the image texture. First, difference in level between streets and sidewalks is extracted from gradients of the dense disparity images at the short range. Next, the template image is set based on the position of the difference in level, and then the curb boundary at the long range is searched for using the template matching techniques. Some experiments in a road environment have confirmed the effectiveness of the proposed method.
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Research Paper
  • Analysis of Bicyclists' Head Impact Situation Against a Car and the Ground in Bicyclist and Car Traffic Accidents Using a Computer Simulation Method
    Yuichi Omoda, Atsuhiro Konosu
    2015 Volume 46 Issue 2 Pages 485-490
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.485
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    The purpose of this study is to clarify the situation of how a bicyclists’ head impacts against a car and the ground for consideration of their head protection methods. To analyze the situation, computer simulation analyses were carried out using a commercialized software called MADYMO. As a result, it was found that the values of head injury criteria became severely high at the head impact on the A pillar and the ground. Therefore, it was clarified that the necessity of taking countermeasures for both the A pillar and the ground to promote a bicyclist's head protection.
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  • Impact Analyses Using a Pedestrian FE Model with Muscular Solid Elements
    Yuko Nakahira, Masami Iwamoto
    2015 Volume 46 Issue 2 Pages 491-496
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.491
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    A human whole body FE model with muscular solid elements, which can represent 3-D geometry of each muscle and stiffness change of the muscle for inputted muscle activation, was applied to sedan-to-pedestrian impact analyses. After the model without muscle activations was validated against cadaver test data of sedan-to-pedestrian impacts, we investigated how muscle activations of a pedestrian in bracing conditions just before crashes would affect the kinematics and injuries of the pedestrian during sedan-to-pedestrian impacts.
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  • Study on Autonomous Driving Intelligence System by Using Optimal Control Considering Risk Potentaial
    Takahiro Hasegawa, Raksincharoensak Pongsathorn, Akito Yamasaki, Hiros ...
    2015 Volume 46 Issue 2 Pages 497-502
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.497
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    Recently, automatic braking systems have been deployed in current automotive markets. However, the existing systems cannot avoid collisions in critical scenario such as a pedestrian suddenly darting out from a poor-visibility blind corner. Therefore, this study proposes a motion planning and control system based on situational risk assessment characteristics of expert drivers. By solving the problem combining potential field and optimal control theories, the desired yaw rate and the desired longitudinal deceleration are independently calculated. In addition, the validity of the proposed motion planning and control system is verified by comparing the simulation results with the actual driving data by expert drivers.
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  • Study on Driver-Vehicle Cooperative Characteristics of Autonomous Driving Intelligence System by Using Steer-by-Wire
    Kou Iwano, Raksincharoensak Pongsathorn, Akito Yamasaki, Hiroshi Mouri ...
    2015 Volume 46 Issue 2 Pages 503-508
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.503
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    Recently, autonomous steering systems for emergency obstacle avoidance have been studied extensively in order to reduce collision accidents. Among these researches, there is a research issue how the autonomous steering assistance function should be designed in order to obtain good driver acceptance when both human and the system conduct the driving task simultaneously as a shared control task. This paper describes the evaluation of shared driving characteristics between human drivers and the active steering system for obstacle avoidance assistance system using the steer-by-wire system. The shared driving characteristics between the driver and the active steering system are investigated by theoretical man-machine system analysis and the driving simulator reconstructing a dangerous scenario.
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Technical Paper
Research Paper
  • The Effects of Attention Allocation while Driving for Preventing Traffic Accident Related to Pedestrians
    Genya Abe, Kenji Sato, Nobuyuki Uchida, Masao Fukushima
    2015 Volume 46 Issue 2 Pages 515-520
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.515
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    The effects of attention allocation and multiple factors (attention allocation with obstruction of view) on drivers' visual and driving behaviour while driving were investigated by using a driving simulator to gain knowledge about characteristics of driving scenes in which traffic accidents related pedestrians may happen frequently. Results showed that there was a possibility that attention allocation led to delayed recognition of a pedestrian resulting in decreased time to the pedestrian and increases in variations in braking response time. Moreover multiple factors induced decreased gazing time of a pedestrian or increases in missing of a pedestrian.
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  • Fundamental Study on Cognitive Performance of Elderly Driver When Approaching Intersection by Using Dual-task Method
    Toshiki Nakamura, Tatsuru Daimon, Toshihiko Oda
    2015 Volume 46 Issue 2 Pages 521-526
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.521
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    This study describes characteristics of cognitive performance of elderly driver when approaching an intersection. In the experiment using a motion-based driving simulator (DS), a dual-task method was conducted, driving task was designed as primary task and memory task was designed as a secondary task. As the memory task, the experiment utilized one-back memory task with single-digit provided by visual or auditory modalities. Driving maneuver, performance of the dual-task and subjective report were analyzed and compared between the elderly and the young and also based on the combination of distance from the intersection and the type of turn there.
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  • Estimation of Switching Condition between Primitive Tasks of Overtaking Behavior on Highway
    Hiroyuki Okuda, Yosuke Abumi, Yuichi Tazaki, Tatsuya Suzuki
    2015 Volume 46 Issue 2 Pages 527-531
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.527
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    This paper presents a technique to estimate a switching condition of the driver between primitive tasks which compose a part of driving scenarios. Overtaking behavior of the driver is focused and measured in the virtual expressway implemented on a driving simulator. Measured overtaking behavior is segmented into several primitive tasks, and the decision making models of the driver to switch the primitive tasks are constructed by logistic regression models. In addition, many candidate variables which can be measured in the driving environment are tested by a chi squared test if the variable plays an important role as the explanatory variable in the model. A quantitative interpretation of the overtaking behavior is provided by considering the obtained model structure and the weights of corresponding explanatory variables.
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  • Numerical Analysis of Turbulent Flow in a Rectangular Duct Containing Straight Cylinder Placed Near a Bottom Wall
    Hitoshi Sugiyama, Toshiki Otemori, Naoto Kato, Atsuhiko Terada, Yu Kam ...
    2015 Volume 46 Issue 2 Pages 533-538
    Published: 2015
    Released on J-STAGE: January 25, 2018
    DOIhttps://doi.org/10.11351/jsaeronbun.46.533
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    Numerical analysis has been performed for three-dimensional developing turbulent flow in a rectangular duct containing straight cylinder placed near a bottom wall. In this kind of turbulent flow, it has been pointed out as a characteristic features that anisotropic turbulence generates the secondary flow of the second kind and pulsation flow is measured in narrow gap region located between cylinder and bottom wall. Comparisons with the experimental results suggest that the present method is able to predict velocity profiles correctly and reproduce both the secondary flow of the second kind and the generation of pulsation flow near the narrow region between cylinder and bottom wall.
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