It has already reported that the coordination of roll and pitch motion has a great influence on roll feeling itself. In this paper, we developed a new damping force control method based on G-Vectoring concept. This method stabilizes a rotation axis of vehicle by the coordination of the roll and pitch rate. The validity and applicability of the control method has proven by computer simulations and the control equipped vehicle's test results.

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In order to enhance a cornering performance of a vehicle, we introduced new longitudinal force distribution method. The method aimed at active control of compliance steer, namely, applied longitudinal force to front inner tire for the increase of steering angle, and rear outer tire for enhancement of opposite steer of rear tire. The cornering performance was evaluated by simulation and test results of control equipped vehicle.

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In this paper, a minimum-time trajectory for cornering of a motorcycle is investigated by means of an optimal control theory. A U-shaped course or S-shaped courses are considered to evaluate the characteristics of cornering. Numerical results show that optimal trajectories are the out-in-out line. During cornering, a roll angle holds constant value while front and rear tire side forces use the maximum value. Furthermore, a velocity is increased during the S-turn maneuver in the middle of the S-shaped course.

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In this paper, we quantitatively verified the effect of a merging assistance system that passes information on approaching cars to the driver using 3D-sound-images.In the experiment with a driving simulator, the scene with a difficult merging action is reproduced, and the judgment of the confluence position by subjects was observed. Moreover, the effect of the system in the merging action was verified by Risk Feeling (RF). As a result of the experiment, in the case of using 3D-sound-image, though subjects almost didn't notice the existence of the 3D-sound-image, subjects came to do the behavior as the RF value became small.

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[in Japanese]

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The study examined the effects of impact velocity and fetus/placenta conditions in frontal impacts using the pregnant FE model developed in the previous study. The model indicated that the loading level to the mother's body was relatively greater when the impact velocity was higher, while no significant difference was found among head positions (up or down) of the fetus and placenta locations in the uterus. Relatively larger strain was found in the placenta when it's located at the anterior wall of the uterus. The results suggested that the loading level to the mother's body would not necessarily correlate to that to the fetus.

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Several control methods that improve the ride comfort of electric active stabilizer suspension system were examined. The examined control methods are the feedback skyhook control, the feed forward skyhook control, and the preview skyhook control. The characteristics of ride comfort performance and consumption energy estimated with the feature of these control methods is theoretically considered. In addition, the actual result of ride comfort performance and consumption energy is experimentally verified.

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Evaluation of body loading paths in a body structure under several loading conditions was performed using U*sum, which enables visualization of internal load paths of body structure. In order to quantitatively grasp the load path distribution characteristics of the frame parts and panel parts under two different loading conditions, an evaluation method using 2-dimensional correlation diagrams which show the U*sum distribution under each loading conditions is proposed.

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Sound Quality (SQ) improvement is one of the important issues in diesel engine development in the past two decades, which sound is composed of intermittent offensive sounds caused by impacting excitations like diesel combustions. The authors, therefore, developed a new method that provides us good SQ indices to establish objective criteria for diesel SQ assessment. Each function of human auditory organs was simulated by computer codes utilizing recent physiological knowledge that gives reasonable analytical explanations of typical human hearing responses to diesel noise. This paper also describes features of implemented functions and applications of the new SQ method on diesels.

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This paper investigates effectiveness and driver acceptance of a driver support system for collision avoidance with situation adaptive steering function. The system sets off an alert when the car is coming close to a pedestrian, and initiates a collision avoidance maneuver upon detecting the driver's braking or turning the steering wheel. The results of a cognitive experiment with a driving simulator showed that the safety was improved by the system and that the participants accepted the system's operation.

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Numbers of traffic accident fatalities in Japan have been decreasing in recent years. However, approximately 5,000 deaths were confirmed in 2009. Therefore, an injury prediction system is considered to be useful for reducing the traffic accident fatalities. In this study, computer simulations of side collision accidents were conducted, and a database of occupant injuries under various accident conditions was constructed. The database was also statistically analyzed in order to determine injury prediction formulas. The injury prediction formulas have explanatory variables that consist of vehicle characteristics, occupant characteristics and accident conditions, and have AIS of head and thorax as objective variables.

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In order to reduce the occupant injury risks by the collision, the optimization of the deceleration of the vehicle is needed. However, the relationship between the occupant response and the vehicle deceleration is too complex. In this study, a finite impulse response (FIR) was applied to predict the occupant responses. Using FIR, it was demonstrated that when the any random input (vehicle deceleration) was provided, the output (occupant responses) could be predicted in high precision.

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This paper focuses on reconstruction of pre-impact speed in a specific type of two-dimensional collision that one vehicle collides eccentrically with another stationary vehicle at a right angle. There is much less experimental data on two-dimensional collision than one-dimensional collision. This is why it is often difficult to reconstruct pre-impact speed in two-dimensional car accidents. This paper introduces effective collision speed (ECS) defined for one-dimensional collision into this type of collision, and confirms the usefulness of ECS for reconstruction of pre-impact speed using actual collision tests.

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NISSAN has succeeded to develop the 75 percent platium group metal (PGM) reduced emission control catalyst compared to conventional one. In order to achieve the PGM reduction for this catalyst, two key technologies are adopted. One is prevention of PGM sintering, which can keep PGM in single-dedigit nanometer range under high temperature conditions. Another is to be faster oxygen transfer rate between promoter and PGM compared to conventional catalyst by locating promoter particle in 1/10 distance from support material of .

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Weight reduction of a piston and wrist-pin causes larger distortion in pin-boss bearing and wrist-pin, and bring poor lubrication condition. Measurement of friction force between the wrist-pin and pin boss bearing is one of the effective ways for analysis of the lubrication condition. The accuracy of the friction force measurement was improved in this study, and quite low friction force of DLC coating was successfully measured.

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Ignition control technologies proposed so far, such as multiple sparks and plasma support ignition, generate active species, ions, atoms and radicals. Lifetime of these species is very short, however, they generate relatively stable OH. Influences of OH addition on Low Temperature Oxidation (LTO) are studied from the view point of chemical kinetics. It was found that when OH is seeded before LTO, extremely small amount of OH addition can shorten the ignition delay to LTO.

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Regarding the cam and valve-lifter with an offset shim for the direct-type valve train in engines, the friction diagram, characteristics and their changes with the test duration have been examined with the test rig, so that effects of the shim surface finish, coating, running-in and contact mechanism on the reduction of friction have been evaluated. Mainly the followings were made obvious. (1)The effect of the surface finish with smaller roughness like an ELID mirror face grind is very large,but that of DLC coating is not so karge. (2)The shim rotaion by the traction force of cam changes the contact mechanism from the sliding to the rolling to make the friction lower. (3)The design is required to promote the formation of hydrodynamic lubricating oil-film between the shim and the valve-lifter.

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The IDI 2-Stroke Cycle CI engine with DME was proposed and, to prevent the leakage of DME, the electrical controlled low-pressure injection system for gasoline engine was applied. The ignition delay could be shorted by the effect of sub-chamber so that the ignition timing could be accurately controlled by the injection timing. However a lot of THC was emitted and thermal efficiency worsened on high load region. Therefore, in this study, the engine performance was investigated for the influence of the engine speed and sub-chamber volume. The ignition timing on sub-chamber was earlier than on main-chamber when the injection timing was advanced. As ratio of sub-chamber volume was increased, on high load condition, high brake thermal efficiency and low THC emission could be achieved because a lot of air was included in sub-chamber. The engine speed 2000min-1 gave high brake thermal efficiency because charging efficiency was improved.

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In order to reduce NOx emissions and the fuel consumption in a direct injection (DI) diesel engine, we pursued combustion and exhaust emissions characteristics under the internal EGR and the external EGR by the theoretical and experimental method. As a result, the following conclusions were obtained. Under the same NOx emissions, the external EGR is excellent in the point of the fuel consumption and the smoke emission compared with the internal EGR. And we were able to find the behavior of EGR gas in the cylinder, combustion and exhaust emissions characteristics under the each EGR.

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In order to reduce exhaust emissions and the fuel consumption in a direct injection(DI) diesel engine, we pursued the intake swirl ratio and the after injection characteristics under the common rail fuel injection system and the high compression ratio. As a result, we could find the conditions improving the relation between NOx emissions and the fuel consumption. The conditions are to delay the fuel injection timing under the low intake swirl ratio and to have a little after injection near the main injection.

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This study aims at finding the favorable combination of combustion-chamber shape and injection parameters when using two-stage injection. The experiments were carried out with various injection conditions, such as spray angle and injection timings and fuel-quantity ratio of two-stage injection, using three types of combustion chamber at low and middle loads. The results show that the strong flow in reentrant-type combustion chamber makes over-lean mixture from first-stage injection at a low load leading to an increase in unburned species emissions, while smoke emission is markedly reduced at a middle load. Increasing first-injection quantity reduces unburned species emissions at a low load but increases NOx emissions. The larger bowl diameter is effective to reduce unburned species emission for later first-stage injection at a low load; however, it causes an increase in smoke emission at a middle load.

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Fuel properties are an important factor affecting diesel ignition, combustion and emissions. An experimental study was conducted to investigate the potential of test fuels to control combustion and emissions without changing the operating parameters. The fuels including paraffinic or naphthenic diesel fuels with or without cetane improvers were prepared in comparison with a conventional diesel fuel. It has been shown that some combinations of these fuels and additives affect ignition characteristics depending on engine load.

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The new diesel combustion concept in the first report was examined in more practical conditions using a multi-cylinder engine. A micro multi-hole injector was designed to create more diluted fuel-air mixture for NOx reduction, and near-zero swirl ports and lip-less cavity were to restrict in-cylinder flows. Such diluted mixture increases more unburned hydro-carbon, and results in worse fuel economy, generally. The restricted flows, however, improve it owing to reducing heat-loss. As a result of complementary effects, our engine showed NOx were reduced to a half of Euro6 standards in the equivalent New European Driving Cycle, without deteriorating fuel economy.

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Response surface modeling of a diesel spray is carried out to achieve the robust and optimal designs of a fuel injection nozzle. A total of seven parameters of the nozzle geometry are chosen as the explanatory variables. They are the number of holes, the diameter, the inclined angle, K-factor, the length, the hydro-grinding level and the sac diameter. The effect of the geometries on the spray penetration and the spread is systematically investigated through the numerical simulations based on D-optimal design. The accuracy of the response surface model is improved by Leave-one-out cross validation method. We conclude that the full second-order polynomial model enables us to estimate the penetration and the spread with practically high accuracy, while it slightly misestimates the largest value of the spray spread. The response surface model is successfully applied to the Pareto optimal design for a penetrating and spreading spray through the multi-objective genetic algorism to elucidate the optimization mechanism.

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The Electro-Hydraulic Variable Valve Actuation (Camless) System, which is one of the key devices for further improvement of fuel consumption and exhaust emission, was being developed. In this study, multi-cylinder engine testing was conducted, which engine has geometric compression ratio of 20 and camless system, and test results are reported in this paper about improvement effect for fuel consumption and exhaust emission under steady-state and transient operation.

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This paper examines a heat recovery alpha-type stirling engine for vehicle exhaust gas energy with respect for its high efficiency and high specific power. First prototype with 0.5L piston displacement, which had zero-side force mechanism and gas lubrication between the piston and the cylinder for minimizing mechanical loss was built and tested. About 710W was generated from exhaust gas with equivalent load of small vehicle at the speed of 100km/h. It was established that this stirling engine had high potential as heat recovery system.

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The authors have developed a control technique of mixture distribution, ignition and combustion processes by use of dual-component fuel and/or two-stage injection. It is still necessary to develop an understanding of the effects of the mixture distribution conditions on the spatial-temporal ignition and combustion processes. Therefore, the present study conducted a fundamental experiment in a rapid compression and expansion machine which uses two injectors. The ignition, combustion and emissions characteristics were investigated for injection timings and mass ratio of fuel injected from two injectors by pressure history analysis, optical diagnostic and burnt gas measurement.

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In order to adapt to the future stringent diesel vehicle emission regulation, it is very important to develop the high performance catalyst for oxidation of diesel particulate matter (PM). We have been trying to develop active catalysts from the viewpoint of activity of oxygen species on or in the catalytic materials, and it has turned out that the Ag/Ce material exhibits high performance particularly. In addition, we investigated the relationship between the contact degree of catalyst/PM and oxidation activity in detail, and developed the new catalyst coating method to DPF to show high performance. In this paper, we report (1) the origin of high activity of the Ag/Ce catalyst and (2) consideration of contact degree of catalyst and PM.

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Experimental studies were performed on effects of emulsified fuel in a diesel engine. At high load, NOx and PM emissions were decreased by 41% and 74% compared to those of diesel fuel respectively. On the other hand, cooling loss and unburned fuel loss were increased and fuel consumption was increased at low load. These increases could be controlled by optimization of the pressure of fuel injection. Estimated emissions on NEDC mode indicated that the emulsified fuel has the potential to comply with Euro6 regulation.

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A diesel particulate membrane filter (DPMF) was proposed to improve the filtration performance and to reduce the oxidation temperature of soot. It consists of two-layer sintered filters, where a SiC-nanoparticle membrane covers the surface of a conventional SiC filter. Soot trapping and oxidation on the surface of the DPMF were investigated in detail using an optical microscope and exhaust gas analysis, and were compared with those of the conventional DPF. The membrane layer plays a significant role for filtration performance because it acts like a soot cake layer. Moreover, the DPMF had some catalytic activity for soot oxidation.

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The potential of alcohol addition by port injection and blended fuel for improving combustion in diesel engines was investigated. NOx reduction and thermal efficiency improvement at middle and high loads were achieved as a result of the characteristics of oxygen content, low cetane number and low viscosity of the fuel. The NOx reduction effects during New European Driving Cycle were shown to be 38% with port injection method and 24% with blended fuel method. Differences in soot generation were analyzed by combustion visualization using an optical research engine.

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This study aims to comprehend the factors of NOx emission increase and to improve this emission performance in a diesel engine fuelled with biodiesel. In this report, the basic combustion characteristics of biodiesel were analyzed by using a single-cylinder diesel engine with applying double and single injection. In addition, the factors of NOx emission increase were considered in detail with using a zero-dimensional simple cycle simulation model. As a result, the factors of NOx increase in biodiesel seem to be changing of fuel spray characteristics or concentrations of chemical species consumed in expanded Zel dovich mechanism.

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Methyl decanoate (MD) is a surrogate for biodiesel fuels. According to results from detailed chemical kinetics modeling, this methyl ester shows shorter ignition delays than long alkanes such as n-heptane and n-dodecane over the whole range of initial temperature. Even at high initial temperatures without low-temperature oxidation, due to easier abstraction of an α-H atom to the carbonyl group, MDxj + O2 → MDxO2 proceeds to MDxO2 → MDxOOH2j (x = 3, m). Also, MDxj → Mymj + olefine and Mymj + O2 → MymO2 proceed to MymO2 → MymOOH2j (x = 4, 5, 6, 7, 10. y = E, P). Here, the nomenclature of species refers to the LLNL's one. These O2 addition reactions to fuel-fragment methyl-ester radicals considerably contribute to heat formation in the initial stage of ignition process, resulting in the short ignition delays.

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An experimental study was conducted to investigate effects of diesel fuels blended with simulated biodiesel fuel (Fuel A) and with BTL (Fuel B) on performance and emissions in a diesel engine for passenger car applications. The results show that both fuels tend to reduce ignition delay, thereby reducing CO and HC emissions without changing NOx. PM emission could be reduced due to oxygen contained in Fuel A. Significant NOx and PM reductions were possible by PCCI combustion using both fuels.

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Fuels which have different composition ratio of saturated and unsaturated fatty acid methyl esters (FAME) are made by mixing several plant based FAMEs. The power is slightly reduced when CME (Coconut ME) mixed with SME (Soybean ME) or PME (Palm ME) because of lower calorific value of CME, however thermal efficiency and exhaust gas emissions are improved, because CME has a lot of oxygen atoms and superior ignitability. The fuel which is equal mixture of SME and CME shows almost the same ignitability as that of PME because weight proportion of saturated and unsaturated FAMEs is almost equal to that of PME.

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Cold weather operation has been a major issue for fuel cell hybrid vehicles (FCHV). In order to counteract this effect on FCHV operation, an approach for rapid warm-up operation based on : concentration overvoltage increase and conversion efficiency decrease by limiting oxygen or hydrogen supply, was adopted in a running fuel cell hybrid vehicle. In order to adjust the output power response of the fuel cell to the target power of the vehicle, -the inherent capacitance characteristics of the fuel cell were measured- based on the oxidation-reduction reaction and an electric double-layer capacitor, and an equivalent electric circuit model of a fuel cell with the capacitance was constructed. This equivalent electric circuit model was used to develop a power control algorithm to manage absorption of the surplus power, or deviation, to the capacitance. It was confirmed that the rapid warm-up operation could follow the output power response and warm-up performance reasonably well, and this control was applied to the FCHV-adv, released in 2008.

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To detect lane-markings and estimate its curvature is the most important technology for autonomous driving. Some conventional methods to detect it were based on forward-looking sensors. However, if relative distance to a preceding vehicle becomes short, it will become difficult to detect it. For this problem, in this paper, side-looking lane-marking detection system using laser range finders is proposed. By this system, it will become more easily to detect it all the time. Moreover, by tracking its position based on Kalman Filter, its curvature is estimated. Based on some experiments, it was confirmed that our method is effective under expressway.

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This study aims to clarify appropriate setting of dual task methodology to grasp the impacts of in-vehicle voice-command interfaces on actual driving behavior. Steering wheel tracking, accelerator pedal tracking, and visual detection response tasks were examined as the candidates of performance measurement task that would be carried out with the target assessed tasks. As the results of experiments, it was found that pedal tracking task was superior as the performance measurement task in terms of the sensitivities among target task differences and the correlations with measures of vehicle lateral displacement and headway distance in actual driving.

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The motor core is usually manufactured from magnetic steel sheet with press machine. However, usually most parts of the plate are scalped, and only about 16% of the sheet is used for the core. The spiral accumulating core system is suitable for manufacturing the core more ecologically because in this system more than 50% of the magnet steel sheet can be used. In this study, a unit cell model is assumed considering periodic character of the actual core under plane strain condition in the z direction. Using this simple model, the effects of the diameter and width of the core are discussed. Also, the effects of the numbers of the slit and embossing interlocking are analyzed. It is found that around the slits the core should be considered as zero elastic modulus because no tangential stress exists. Also, a simple evaluation method is proposed to estimate the effective elastic modulus by applying the rule of mixture to the simple model.

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This paper describes the method of calculating nominal structural stress which is correlated with the fatigue strength of the spot-welded joints. The stress analysis is curried out using plate theory in elasticity and the data of displacement field around the spot weld derived from analyzing the finite element model of the spot-welded structure is used but no general loads are used. It is confirmed that the proposed method makes the value of the nominal structural stress excellent and the transferability of spot-welding S-N test data can be established using the nominal structural stress based parameters.

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In the case of a hydrogen gas cycle, the gas temperature rises by filling, and temperature falls by discharge. On the other hand, a hydraulic pressure cycle is conducted at a constant temperature. We investigated the stress state of VH3 compressed-hydrogen tank when environmental temperature and filling pressure are changed. As a result, it is revealed that the stress range of the hydraulic pressure cycle is larger than the gas cycle by heat stress.

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The car accident occurs easily at nighttime. Especially, the fatal accident ratio occupies half of vicinity at nighttime. Moreover, the accident to the pedestrian because of the low beam use at dark night is pointed out, and the remedial measures are requested. In this research, the driver view of driving at nighttime was analyzed by using the computer graphics simulation that was able to consider the visual characteristics. It was clarified that there was a possibility that the visibility decreases oppositely by glare veiling, too, when there was an oncoming car to be near.

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We are developing A Survey Simulator to Evaluate Safety Systems (ASSESS) that virtually reproduces a real intersection and traffic flow in which vehicles run autonomously in the computer. In this study, the validation of the reproducibility of ASSESS for real traffic flow is confirmed. Furthermore the algorithm to simulate the driver's recognition error and operation error is verified based on the change in number of accidents and near miss incidents.

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We have established an index of the longitudinal risk estimate called "PRE" based on human perception (feelings of "approaching" and "coming") and validated it by actual vehicle tests. The PRE was compared with other indices such as TTC, RF, and KdB_c, and it was shown that the PRE is a comprehensive and enhanced model of those indices.

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The topmost cause of accidents among older drivers is an unintended stop-sign violation. We investigated the environmental factors that cause older drivers to fail to see a stop sign and unintentionally pass through an intersection. Ten older (67-78 years) and ten younger drivers (21-24 years) participated in this study. Participants drove a car following the experimenter's navigation guidance, and were asked to obey the traffic rules. The results indicated that, unlike the younger drivers, older drivers sometimes did not stop at the stop lines under specific conditions, and that these non-stop behaviors were observed in only half of the older participants. hese findings indicate that awareness of stop signs among older drivers is not only related to visual barriers and the prominence of signs, but also other environmental conditions and individual differences.

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The number of traffic accident casualties has been decreasing due to the improvement in automobile body structure, occupant protection system, and emergency medical care. However, the number of the persons injured in traffic accident remains high. Therefore, it is crucial to analyze actual accidents in order to design concrete safety measures for future automobile safety. In this study, a database linking traffic accident, permanent disability, and traumatic injury was developed. By using this database, an in-depth analysis of injuries, occurrence of permanent disabilities, and accident types in relation to the different affected parts of the human body were conducted.

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This paper addresses the method of estimating hazardous routes by utilizing the near-miss incident data collected by probe-cars. To discriminate a near-miss incident from usual deceleration behavior, the discrimination method using jerk and maximum deceleration is proposed, through analyzing JSAE's database of near-miss incidents and data of intentional deceleration behaviors. The frequency rate of near-miss incidents data discriminated by the proposed method is compared with that of fatal accidents on each route of three high-accident intersections in Hiroshima city. Each rate of straight-ahead and left-turn routes has shown similar tendency, so the proposed method could be valid.

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The key point of the research is to improve the eco-driving performance in a hybrid truck among various drivers. In the previous paper, a hybrid electric vehicle (HEV) controller consisting of an automatic gear controller and a hybrid torque distribution controller with a driving torque feedback compensator has been proposed and verified by simulations. In this paper, the proposed hybrid control system has been verified by a driving simulator with several real drivers. The result indicates that the driving performance and fuel economy of the HEV among various drivers were improved by using proposed hybrid control system.

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It is understood that the tyre characteristics change with tyre temperature. This paper shows the influence that tyre temperature has on tyre cornering characteristic. This influence was also mathematically modeled utilizing vehicle characteristics. In addition, the tyre temperature was measured on the public road, and then vehicle performance was estimated based on the measured tyre temperatures.

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This paper describes a development of dummy FE models to be used for side impact simulations. The precise geometries of the ES-2re dummy and the SID-IIs dummy were measured at a pitch of 1.0 mm using X-ray CT scans. The material properties and the mechanical responses of the components were measured in static and dynamic tests and were used for the model validation. Both dummy models showed a good correlation when compared their kinematics and injury index values to those in the full vehicle side impact tests.

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