On-Center handling subjective evaluation by drivers and objective evaluation by low frequency sinusoidal torque input test clarify on-center handling mainly depends on the increasing characteristics both steering torque versus steering angle and steering torque versus yaw velocity from center point of steering. Steering stiffness for driver at the steering wheel decreases from the center point as the steer torque increase by the series of stiffness element and spring-friction elements. Spring-friction elements in the steering system make nonlinear steering stiffness smoother and shorter the delay of wheel steer. Adequate stiffness of steering system and proper friction torque in spring friction elements, proper distribution of the stiffness elements and spring-friction elements enable to realize the higher steering stiffness from the center point of steering.

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The purpose of this work is to analyze on-center steering feel by using a steering simulator. Firstly, it is revealed that the steering feel is evaluated based on equality of sensation while steering and the sensation is derived from steering torque and stiffness of steering system. Next, perceptual and discrimination characteristics of both the steering torque and the stiffness of steering system were examined. Finally, ideal steering characteristic which can provide the equal sensation is formulated by the perceptual characteristics. Moreover, it is confirmed that steering characteristics whose steering feel are highly evaluated are strongly correlate with the ideal characteristic.

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Aerodynamic coefficients and pressure distributions of flow around a bluff body with rounded edges were measured by wind tunnel test. Numerical simulations of flow around the bluff body were executed by using Large Eddy Simulation (LES) with Dynamic Smagorinsky Model (DSM). The experimental and numerical results were compared. Large Eddy Simulation accurately computed laminar separation around the rounded edges. However, the computational accuracy of laminar separation around the other corner edges was lower than that around the rounded edges. Therefore, the computational accuracy of the aerodynamic coefficients has decreased in case of yawing angle of 30 degrees.

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Exhaust noise level measured by current ISO5130 correlates weakly with accelerating vehicle noise by ISO362, because ISO5130 measures noise in engine coasting condition. In this study, a new alternative stationary exhaust noise test was proposed. In this test, exhaust noise is measured when the throttle is opened quickly and fully from the idle position. The exhaust noise levels were measured in the proximity of the exit of mufflers under the conditions of the alternative test and the current ISO362 simulated on the chassis dynamo meter. Those results were compared and the validity of the alternative test was investigated.

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In order to prevent the maneuver-induced rollover of a 3-axle straight truck, a rollover prevention system based on independent brake force control is proposed. The differential braking is calculated by solving a robust stabilization problem in consideration of the variation of vehicle speed and tire cornering stiffness. The criterion of rollover risk is also analyzed, and a logic combination of lateral acceleration and roll motion is used to judge rollover risk. Finally the proposed rollover prevention system is tested on a truck simulation model constructed by TruckSim. Simulation results of J-turn maneuver and lane change maneuver show that the proposed system can prevent rollover effectively.

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A driver and a passenger of a compact car died with abdominal injuries in a head-on collision accident. They are supposed to be pressed by the seat belts because the front parts of the seats deformed downward in the accident. So we tested the strength of the seats of some passenger cars. The test revealed that the seats of the crashed car were obviously weaker than the others. We think the seats of passenger cars must have the sufficient strength to support the occupants strained by the seat belts who move forward by crash.

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This paper describes a study of driver behavior and steering actions based on visual and motion stimuli using a vehicle with an electric active suspension system and a rolling simulator. The effects of vehicle lateral acceleration, visual/motion stimuli and steering operations on driver behavior, and steering operations were analyzed separately.

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A human FE model was used to clarify the mechanisms of the hip sliding. Using the model, the moment on hip around the center of gravity was investigated when it sit on a rigid seat. It was found that the backward moment around the hip CG induced by the interaction force between hip and seat was the main cause of hip sliding. A hip sliding equation was constructed based on the relationship of the cushion angle underneath of hip and the interaction force. And its validation against volunteer tests using car seats was introduced.

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The purpose of this study is to investigate the effect of striking vehicle body types on the struck vehicle's occupant injuries in side impact crashies. The accident investigation findings indicated that the ratio of fatal and serious injuries to all injuries of occupants in struck passenger vehicles was highest when the struck vehicle was impacted laterally by an SUV or one box type vehicle. The results from side impact crash testing, where an ECE/R95 MDB, a passenger vehicle, and a one box type vehicle impacted the side of the same model passenger vehicle, indicated that the injuty measures for HPC was lowest and thoracic rib deflection and V^*C were highest when the one box type vehicle was the impacting vehicle.

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From the energy security and CO2 discharge reduction point of view, much attention has been paid to the usage of bio-fuel. Yet, the major subject in applying highly concentrated ethanol in SI engines is to sustain stable cold startability and emission. This is due to the characteristics of ethanol, large latent heat required to vaporize. In this Paper, evaporation of highly concentrated ethanol at HC cold temperature, which is a determining factor of exhaust emission, are analyzed quantitatively.

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There was concern that a variable compression ratio engine fitted with a multi-link mechanism might produce louder booming noise due to the inertial forces caused by the lateral swing of the links. Accordingly, a relational expression between the inherent characteristics of the links was found to counterbalance those forces. Therefore, this engine, which has no balance shaft, is expected to have a booming noise level lower than that of conventional engines.

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A hybrid combustion of flame propagation and end-gas auto-ignition by applying hydrogen addition to low octane number fuel has been successfully demonstrated. Stable lean combustion with significantly low NOx emission and less unburned fuel has been observed. The effects of hydrogen ratio and fuel octane number have been investigated with RCEM experiment, as well as the effect of hydrogen addition to ignition delay time has been studied by using detailed chemical kinetic simulation.

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Owing to the flat-shaped combustion chamber and the extremely strong one-way mixture flow, the combustion characteristics of Rotary Engine(RE) are quite different from those of ordinary reciprocating gasoline engines. In this paper, detailed RE combustion was observed using a high-speed camera and visualization apparatus such as optical RE and Rapid Compression Machine. As a result, the ignition and the flame propagation of RE-specific combustion was clarified. Furthermore, to achieve faster RE combustion for improving the fuel economy, or reducing CO₂ emission, the effect of spark-plug arrangement on flame propagation was observed, that is, the multipoint ignition was examined using the combustion simulation, the visualization apparatus, and the real RE.

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Multi-ignition method using auto ignition of diesel oil as ignition source was studied with the aim of improvement of anti-knock performance in a gasoline engine. The experiment and numerical analysis showed that combustion duration was controlled by combustion start timing and spatial distribution of diesel oil, respectively. The widely spreaded distribution of diesel oil prior to ignition onset could realize fast combustion without knock, therefore, indicated thermal efficiency was improved.

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For the reduction of exhaust emissions of diesel engine, an improvement of DI diesel engine system were carried out by using GTL fuel, which is expected as an alternative fuel. In this study, the combustion chamber, injection pattern and EGR calibration were modified utilizing combustion characteristics of GTL fuel. In addition, after-treatment system for zero sulfur fuel was studied to realize high conversion efficiency of NOx catalyst. As a result, it was found that the optimization of the engine system with GTL fuel enables to realize an excellent potential of exhaust emissions.

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The effect of combining high pressure loop (HPL-) and low pressure loop (LPL-) EGR systems on engine performance and emission characteristics were investigated using a multi-cylinder diesel engine under steady-state conditions. At low load, increasing HPL-EGR rate causes higher soot emission whereas increasing LPL-EGR rate causes higher fuel penalty. To solve this problem, combining HPL- and LPL-EGR systems at low load can reduce exhaust emissions without fuel penalty. At high load, in contrast, since pumping loss is low effect on fuel consumption, increasing LPL-EGR rate with higher boost pressure can reduce NOx and soot emissions simultaneously.

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Improvement of diesel combustion and emissions with promotion of premixing by ethanol port injection as well as with reduction of combustion temperature by EGR was attempted. The smoke emission was reduced with promotion of premixing due to longer ignition delay and shorter injection period of diesel fuel with ethanol port injection, and the NOx was reduced with decreases in intake oxygen content by EGR regardless of ethanol quantity. When ethanol quantity was set at 20% in total energy supply and intake oxygen was reduced to 15% with EGR, smokeless and low NOx operation was established for wide load range.

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Application of biodiesel to diesel engine is very effective to reduce CO₂ emission. However, it is likely that biodiesel causes the deterioration of emission characteristics of modern diesel engines. In this study, the effects of biodiesel blending on combustion and emission characteristics of modern diesel engine were investigated. Biodiesel blending reduced engine-out CO and HC emissions and these components were sufficiently oxidized by oxidation catalyst. On the other hand, biodiesel blending increased engine-out NOx emission and deteriorated the NOx reduction performance of NOx storage reduction catalyst. Tail-pipe PM emission was also increased by biodiesel blending in high concentration, in spite of low engine-out soot emission.

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The authors have completed measurement of instantaneous temperature on all the combustion chamber wall surfaces (i.e. the piston, the cylinder head, the cylinder liner, the intake and exhaust valves), and evaluated instantaneous heat flux from the combustion gas to each part of the combustion chamber by heat transfer analysis of the measured temperature. In this paper, distributions of the surface temperature and the heat flux on respective combustion chamber wall surfaces are presented.

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Exhaust gas aftertreatment system are thought to be necessary for low emission diesel engine. Combustion control and aftertreatment control must be optimized because the reduction performance of aftertreatment system strongly depends on exhaust gas temperature, components, and so on, and the aftertreatment control consumes some amount of fuel. In this paper, the possibility of controlling NO₂ emission quantity is investigated and reported, because NO₂ is known to be effective for continuous oxidation of particulate matter (PM) in catalyzed soot filter, and it is absorbed as nitrate in NOx storage type catalyst. .

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The combustion characteristic timescale model by Kong et al. was applied to zero-dimensional chemical kinetics calculation with a detailed elementary reaction scheme in order to predict combustion processes under various operating conditions in a gasoline HCCI engine, and it has been shown that combustion processes as well as ignition timings can be predicted by means of this method. The effects of initial chemical species compositions on ignition timing were investigated by zero-dimensional chemical kinetics calculation, and the mechanism of ignition promotion due to CO was inferred on the basis of Kuwahara's contribution matrices.

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Thermal and mixing stratifications have been thought as one of the way to avoid a sharp pressure rise on HCCI combustion. The purpose of this research is to evaluate the potential of thermal and mixing stratifications for reducing pressure rise rate on HCCI combustion. The pre-mixture with thermal and mixing stratifications is charged in Rapid Compression Machine. After that, the pre-mixture is compressed and on that process, in cylinder gas pressure and chemiluminescence images are obtained and analyzed.

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The effects of NO₂/NOx ratios at the inlet of SCR catalyst on NOx reduction efficiency were investigated by using a multi-cylinder diesel engine. NOx reduction efficiency at low exhaust gas temperatures significantly improved in NO₂ rich conditions by increasing NH₃ adsorption quantity on the SCR catalyst. NH₄NO₃ formation reaction is enhanced by NO₂ and NH₃ contributed to reducing NO₂. In contrast, the improvement rates of NOx reduction efficiency in NO rich conditions with enough NH₃ adsorption quantity were limited due to the temperature dependence of the standard SCR reaction.

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In reciprocating HCCI engine, in-cylinder gas pressure and temperatue rise rate chane during Compression stroke depending on engine speed. As a result, auto ignition timing and rate of heat release change. Then, the purpose of this study is to investigate influence of engine speed on combustion characteristics such as temperature of ignition, combustion duration and combustion efficiency by using numerical analysis. And this study used methane without negative temperature coefficient and DME with negative temperature coefficient as fuels to deliberate the relation between characteristics of shock tube's ignition delay and HCCI combustion.

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In the previous report, the authors have explained the difference of combustion characteristics and diesel emissions between rapeseed oil methyl ester (RME) and diesel fuel in high boost charged system and high-pressure common-rail injection system. In this study the mass of exhaust particulate matter (PM) of RME and diesel fuel were measured quantitatively at various experimental conditions, which were changed from 0% to 40 % of EGR rates at 1200rpm and full load in single cylinder engine. The soluble organic fraction (SOF) in PM was analyzed in order to separate fuel and lubricating oil by gas chromatograph.

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The toroidal traction-drive CVT transmits power by the shearing action of lubricant film under heavy loads at the contact ellipse on the rollers. Furthermore, due to the geometry of the toroidal CVT, spin motion is produced in the contact ellipse. These contact ellipses are where shear stress of the lubricant generates frictional heat. In this report, temperature rise in the traction contact areas of toroidal CVTs were analyzed using a traction analysis program after measuring temperature rise with a twin-disc test machine and comparing experimental results with calculated results. The influences of half-cone angles on temperature rise were discussed.

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A subject of reducing the PGM applied on a catalytic converter is a decline in its NOx conversion efficiency. This paper investigates the primary factor of this decline to be HC poisoning. To maintain higher NOx conversion efficiency as the PGM reduces, the Rh activation improvement becomes significant, overcoming the HC poisoning. As analysis conducted on Rh deterioration mechanism, it is effective to separately arrange Rh and CeO2 on the converter, improving the Rh activation. By this improvement, we confirmed a reduction effect more than 25% of Rh loading.

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Since natural speech includes a large variety of expressions, natural speech recognition is much more difficult than recognition of specific commands. We developed a language model template that can generate language models which can recognize various expressions. Designed to facilitate recognition of voice commands consisting of various expressions, this template is based on modification structures of keywords. The evaluation results showed that this proposed model was capable of recognizing nearly 630,000 patterns with a high correct recognition rate of approximately 96%.

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A position information of a vanishing point is necessary to estimate three dimensional information using optical flow in the image obtained from in-vehicle camera, however, the vanishing point would not exist when a host vehicle turns. Therefore, in this paper, we propose a new technique for estimating three dimensional information in which the vanishing point is not used by extracting optical flow in each area classified into vehicles, the road surface, and the background regions.

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Connection stability in vehicle-to-vehicle (V2V) communication is important for applications handling urgent message, such as cooperative driving. Many kinds of mobile ad-hoc network protocols have been proposed; however, there should be possibility to improve data dissemination performance specially for V2V communication by using characteristics of vehicle location information and camera sensor information. We propose a method of ad-hoc network construction with the characteristics to improve connection stability and evaluate the performance with a network simulator. A camera sensor detects each vehicle's location. Vehicles driving in each lane form a group and a network address is assigned to each lane.

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It is very important to develop the high performance three-way catalysts for meeting regulations world-wide. We found that double layered catalyst loaded Pt and Rh suppresses Pt-Rh alloying and that makes its catalytic performances higher. Therefore the developed catalyst could reduce about 40% PGM amount.

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This study addresses the experimental investigations into the solution stability of oxidized biodiesel in petro-diesel. When extremely oxidized biodiesel is blended in petro-diesel, highly viscous polymer is separated from biodiesel/petro-diesel blend because of difference in polarity. With reference to this phenomenon, reforming of biodiesel fuel by means of a solvent fractionation has been demonstrated to improve the oxidation stability of biodiesel. Firstly, unsaturated fatty-acid methyl esters, which have poor oxidation stability, are polymerized by oxidation treatment, and secondly, they are removed by a solvent fractionation. As the result, content of saturated fatty acids is successfully increased.

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In this research, BDF is made light quality by mixed with low boiling point fuel that is lower than BDF. This method has the effect that physical characteristic of BDF is improved. Purpose of this study is to evaluate soot formation and exhaust characteristic of the mixing fuels. The soot formation characteristic of the mixing fuels are investigated by Laser Induced Incandescence(LII) using a constant volume combustion vessel. The exhaust characteristic of the mixing fuels are measured with a stationary engine. The result of the engine experiment shows that smoke decrease without NOx increase by mixing BDF with low boiling point fuel.

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Contactless rapid charging inductive power supply (IPS) system has been developed and tested as a charger for small size electric-driven vehicles. By using the developed system, charging can be carried out safely, easily, and in a short period. Optimizing the external circuits of track and pick up of IPS achieved significant improvements in efficiency, power factor during non-contact power transmissions. This paper also reports on the development of Waseda Advanced Electric Vehicle (WEV) equipped with developed IPS system.

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We performed molecular level simulations so as to elucidate the atomistic operation mechanism of fuel cell systems, which used the noble metal catalyst as an electrode. The performance of these catalysts is closely related to the energy efficiencies or maximum power of fuel cell vehicles, especially in the case of proton exchange membrane type fuel cell (PEMFC) that thought to be the current standard for automotive application. To this end, we have developed a simulation model that allows catalytic activity prediction based on quantum mechanics simulations.

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This paper proposes the control for platooning and the control for changing formations of a platoon. The platooning of vehicles has been developed in the field of Intelligent Transport Systems aiming at enlarging traffic capacity or laborsaving. If the platooning of electric light vehicles with very short inter-vehicle distance is realized, it is expected to stretch the limitation of electric light vehicles, because small capacity of the electric light vehicles is timely enlarged, resulting in giving a potential to apply them to more various purposes. This study is aiming at enhancing the maneuver at platooning of electric light vehicles and has developed the control method for changing formations from a single-line formation to a double-line formation and from a double-line formation to a single-line formation. This paper describes the proposed method of control for changing formations and reports the experimental results using four electric light vehicles.

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This paper presents the development of the modeling of human driving behavior based on a mode segmentation of the measured driving data. In our modeling, a relationship between the diver's sensory information and the output of driver is expressed by the piecewise ARX (PWARX) model, which can represent wide variety of dynamical characteristics by assigning different ARX models to different modes. By introducing the PWARX model, it becomes possible to find not only parameters appearing in the operation in each mode but also parameters in the logical switching (decision making) conditions between modes from the measured driving data. Furthermore, the obtained model is exploited for the design of assist system.

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The purpose of the study is to classify elderly drivers in order to clarify their driving behavior. The classification approach will help us to understand the characteristics and will lead to develop driver assistance systems and education programs in order to prevent traffic accidents of aged drivers. We first applied cluster analysis to driver parameters acquired in driving simulator and questionnaire studies. The result classified subjects into several clusters. We then performed linear discriminant analysis . Depending on the results, we can classify aged drivers with high probability. Evaluation of the linear discriminant functions also revealed characteristics of each cluster.

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Authors conducted indoor test to investigate the difference of brake response time due to four kinds of workloads for information processing. The fifteen participants were instructed to gaze at the display in vehicle and to press down the brake pedal when the stop lamps on the lead vehicle were lit after returning his/her line of sight to the forward direction. The results show that the difference of workload levels causes the delay of 0.3 seconds of brake response time. However, compared with the case of straight looking forward without looking aside, the safety level is greatly deteriorated when the driver is gazing at the display device.

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This report discusses driver's normal avoidance behavior to the crossing pedestrian systematically. Some factors which influence driver's avoidance behavior are picked up by observing real traffic situations. The factors which influence the behavior largely are selected by the driving simulator tests based on experimental design. It is clarified how each factor influences the behavior. The sequence of driver's avoidance behaviors is as follows. A driver releases the accelerator by predicting danger to the pedestrian. Then, a driver puts on the brake by judging danger. Finally a driver presses the accelerator by confirming departure from the lane.

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In this study, field tests with passenger vehicles were conducted to develop a method to provide useful "smart" information to drivers. The proposed method is a three-step procedure to train navigators to enhance their skill to serve a useful information to the driver. Conversations between drivers and navigators were recorded during driving. After each driving session, the contents of conversations were further investigated by conducting interviews to the participants in order to clarify the elements that make the information to the drivers useful and acceptable. The result shows that the followings are the elements of useful information: cntents of the regional specific information, information to change driving operation more smoohtly, and information that matches driver's favor.

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The present paper proposes DCA (Deceleration for Collision Avoidance) as a new index to determine the warning provision threshold of a FOCWS (Forward Obstacle Collision Warning System). The DCAs in the case when the preceding vehicle keeps the current acceleration and in the case when it will decelerate hardly are defined as ODCA (Overt DCA) and PDCA (Potential DCA), respectively. Numerical simulations are performed to compare the DCAs with the TTC (Time-To-Collision) and MTC (Margin-To-Collision), which are well-known indexes to evaluate the potential collision risk in the situation where the collision risk against the forward obstacle becomes high.

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The present paper proposes a method to provide a collision warning of a FOCWS (Forward Obstacle Collision Warning System) based on DCA (Deceleration for Collision Avoidance). First, driving simulator experiments are performed to identify a reaction time which is an essential parameter for calculation of the index. Next, we propose a new FOCWS which provides drivers with a real-time indicator of the DCA as visual information in addition to a warning sound as auditory information. Driving simulator experiments are conducted to verify the effectiveness and acceptability of the proposed system.

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In preparation for realizing assistances and educations drawn on the concept of "keeping off the accidental risk", general drivers' unsafe driving behaviors were collected and analyzed on the basis of the frequency and the risk. Furthermore, the effects of the instructor's advice on the behavior modifications were analyzed for the purpose of the future investigations into the effects of the new assistances and educations. Through these fundamental reaserches, a new concept of accident prevention, the reformation of driving habits prior to getting into danger, was introduced.

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The computer graphics simulator that reproduced the driver's view was developed. This simulator can consider the change in the glare veiling by aging. How the glare sensation of headlight changed according to the age and the road shape was analyzed by this simulator. It was clarified to be able to attempt the improvement of glare by the optical axis control. An aged driver occasionally decreases the visibility of the pedestrian crossing the road by glare veiling.

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A laboratory experiment which simulated error of overlooking while driving was conducted. Since relationship between mental workload and depression of function of eye movement and dynamic visual acuity was not clear, individual attentional characteristic was introduced to clarify. From the fact that the eye movement was depressed by the increasing workload only in low "ability to control cognitive processes" group, and from analysis by "tnedency to perform tasks concurrently" group, it was through that the eye movement was affected interactively by the workload and the attentional characteristic, and that intrduction of individual characteristic to visual cognitive error study was useful.

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We have proposed "Judgement Line of Brake Initiation" (a discriminant which models a driver's timing to start decelerating) in phase plane of the index(KdB_c) and the gap(D). It was determined by a test driver's brake initiation in moderate danger levels. We conducted experiments wiht several subjects in a proving ground and recognized differences among individuals. In this paper, we propose a mehtod to adapt "Judgment Line of Brake Initiation" to individual drivers in public roads.

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Drivers' properties detecting visual targets were investigated. White dot targets were presented on a screen and both the error rate the detection times were measured. Investigated factors effecting on these detection performances were follows; presentation type(appearance or changing size), size of target, and the background. As the results of experiments, more detection errors were observed in the case of the small target presented at far from the fixation point with dot-texture background. The following factors increased the target detection times; target presenting at peripheral regions, lower rate of changing size, small size, wiht dot-texture background. "Detection maps" were illustrated in order to understand the drivers' properties of visual detection intuitively.

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Vehicle-infrastructure cooperative safe driving support systems driving are introducing into road traffic environment in Japan. It is important to consider better designs of display interfaces in order to maximize effects of the systems. The research aims to suggest some ideas of designing better visual displays which give drivers information about traffic situations that can not be seen directly by them. The driving simulator experiment was carried out. In the experiment, the simulated system worked on the dangerous traffic situation of crossing-path collision at intersection. The results showed the visual display by letters was able to make drivers' reaction time to the dangerous vehicle faster than by moving image if there was no enough time for drivers to see the vehicle. It is necessary to select visual displays according to the traffic situations where the vehicle-infrastructure cooperative system works.

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This paper presents an approach to minimize weight of suspension parts while keeping the fatigue strength base on a non-parametric boundary shape optimization theory. As an index for the fatigue failure, we considered the maximum valueof absolute principle stress in a suspension part evaluated from actual loading history. For reshaping, we employed the traction method to keep the smoothness of original boundary.To reduce computational time, we considered a conventional method to select critical loading cases from actual loading history. By our approach, we obtained about 10% weight reduction while keeping the maximum value of absolute principle stress constant.

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