An in-vehicle front camera has come to be used a lot by a drive recorder, and a back camera is also popular. Then we propose a new method to detect following vehicles using these two cameras. A scene imaged by front camera will come out at back camera after a few seconds when a host vehicle is running. Therefore it is possible to detect following vehicles by comparing these front and back images. If we see the same road situation, it means no vehicle. If there is not the same object in the back image, there is a vehicle backward. To analyze these situations we use projective transformation. In this paper, we show details of our proposed method and validity by experiments in typical situations such as front and back vehicles, only front vehicle, only back vehicle and no vehicle in front and back.

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This paper presents a numerical analysis for trajectory optimization problem of a circuit racing car. Course examples are configured to be a part of real circuit. A solver used to analyze an optimal control problem is based on a pseudospectral method, a direct method, which can handle a state variable inequality constraint of a course restriction easily. Numerical results show that the racing car maneuvers at th limit of its performance envelope. Comparing with the real racing car data, an applied method yields appropriate results.

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This paper describes the estimation algorithm of the driving steering intention based on Brain-Computer Interface (BCI) using electroencephalogram (EEG). The estimation algorithm of the driving steering intention was examined and developed. Experiments were conducted with 3 able-bodied subjects using driving simulator (DS). The drivers were instructed to operate the vehicle according to the series of three kinds of instructions (right steer, left steer, straight running, and stand by). Those instructions were given to the subject with random order, after the operation trigger had been signaled. The off-line analytical result shows that the driver's steering intention can be estimated at the averaged probability of about 80%.

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Longitudinal force acting on a small size tire and sinkage due to the interaction with dry sand were measured on wheel drive test under constant-sinkage and constant-slip-velocity conditions, respectively. Based on the collected data, a tire model, which calculates longitudinal force and sinkage, utilized for vehicle motion analysis on sand was approximately expressed as simple functions of slip ratio, wheel normal load, and travel distance. In order to validate the tire model, a numerical simulation of self-driving wheel at a constant rotational velocity on sand was conducted. The numerical results showed good agreement with the experimental data.

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A tactile interface is expected to be effective information display for driver assistance systems. It is important to clarify the relation between the physical characteristics of seat vibrations and the perceived urgency carried by that signals. In this paper, we propose an urgency-map that shows the relation between the basic seat vibration characteristics of alarms (frequency, pithch and intensity) and the individual perceived urgency. And we conducted an experiment to study the efficacy of a seat vibration alerts and how they affect a driver's response to imminent situations while distracted.

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Reduction of unevenness of occupant injury index in frontal collision is important in vehicle development. The author analyzed the unevenness in chest deceleration on the passenger side by using a FE model. Results show that there is a wide unevenness in internal force of lumbar spine. It was found that modification of the seat structure layout reduces the unevenness in chest G by 40%.

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In addition to the requirement of crush safety improvement in resent years, a demand for an material-saving measure because of soaring material price is increasing.
This study shows the body structure enables high-efficiency energy absorption without weight increaseby improving on a frame structure to be conformed to the rear-offset crush test mode introduced in North America. And an appropriateness of the structure is demonstrated by CAE and experiments.

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3-D CFD HCCI combustion simulation was conducted with a newly developed PRF skeletal kinetic model. The developed model was based on auto-ignition model of Tanaka et al. with consideration of decomposed intermediates, olefines and aldehydes, and also a high-temperature oxidation path with a set of minimum reactions for ethylene oxidation. The new model was validated for shock tube experiments, HCCI gas-sampling and wide range of HCCI experiments, and validated results showed excellent agreements. The new PRF model was also applied to 3D-fine meshed CFD HCCI simulation of dual fueled HCCI combustion and the mechanism of ignition enhancement was discussed.

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The method to detect knock location was developed, which utilized the arrival time delays of the pressure wave between several pressure sensors in the combustion chamber of the gasoline engine. In this method, the time delays were derived from the time-frequency analysis. The calculated knock location by the least square method satisfied the result of the experimental time delays in a minimum error. This method was applied in various conditions in a single cylinder engine, showed effects of swirl and weak stratification with a port injection and a direct injection.

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A newly developed small-sized IES circuit with semiconductor switch at turn-off action was successfully applied to an ignition system. This IEC circuit can generate repetitive nanosecond pulse discharges. In this paper, the ignition system using repetitive nanosecond pulse discharges was investigated as an alternative to conventional spark ignition systems. The experiments employed were conducted using spherically expanding flame configuration for C₃H₈-air mixtures under various conditions. In conclusions, the ignition system using repetitive nanosecond pulse discharges was found to extend lean flammability limits compared with conventional spark ignition systems. In addition, the ignition system using repetitive nanosecond pulse discharges could shorten ignition delay time.

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The effect of NVO combustion on thermal efficiency was investigated with a cycle simulation software realizing an HCCI combustion analysis. As a result, it was found that shorter NVO duration with NVO combustion was able to ensure better thermal efficiency keeping ignitability. It is necessary to set EVC, IVO, and the NVO fuel split ratio in consideration of the ignition timing, the pumping loss, and the expansion ratio of NVO combustion to obtain the best thermal efficiency in the case of NVO combustion.

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In this study, unburned hydrocarbon (HC) emissions of a Premixed Compression Ignition (PCI) engine fueled with DME (Dimethyl ether) were investigated by experiment and numerical simulation. According to the results of experiment, it was shown that a considerable amount of HC emission was exhausted during the advanced injection timing, and as the injection timing was delayed, HC emission increased temporarily, and then it decreased remarkably. The volume of the piston top land and piston ring crevice effect the HC emission strongly. Both of the contribution of injection timing and the volume of the piston top land and piston ring crevice on HC emission were analyzed by simulation of mixture formation using GTT code.

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The new material having new soot burning mechanism was found out as high-performance soot burning catalyst for diesel particulate filter, which mechanism was different from conventional materials having oxygen exchange reaction property. The material showed the superior effect on soot burning performance even with low precious metal loading condition and possessed high thermal durability. High soot burning performance was confirmed even at actual emission gas condition.

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To independently analyze the effects of lowered combustion temperature and improved fuel-air mixing with ultra high EGR on smoke reduction,fuels with five cetane numbers as well as three compression ratios were systematically examined.Smokeless combustion was realized 1)at the "premixed-combustion state" when the premixed duration defined as the period between the end of fuel injection and ignition is larger than 4°CA regardless of combustion temperature; and also 2) with sufficiently low combustion temperature at the "premixed-combustion transition state" when the premixed duration is between 0 and 4°CA. A combination of low compression ratio and low cetane number fuel is advantageous to realize smokeless combustion.

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Pre-mixed compression ignition (PCI) combustion of low NOx emission was performed in a multi-cylinder diesel engine in a previous paper. In this study, a two-stage turbocharger was applied on test engine to actualize PCI region expansion and emission improvement. The test result showed a large reduction effect of emission was provided by applying a two-stage turbocharger and by controlling EGR gas temperature during test cycle. Further, the emission of the conventional diesel combustion also improved by performance improvement of supercharge with new turbo system. Finally, adaptability of engine out NOx emission on US Tier2 regulation was examined.

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A laser 2-focus velocimeter (L2F) with a micro-scale probe was used for measurements of velocity and size of droplets in diesel sprays near the spray center 15 mm downstream from the nozzle exit. The injection pressure was set at 40 MPa by using a common rail injector. The data sampling rate of the L2F system has been increased to 15 MHz. The number density of droplets was estimated by data of velocity, size, and time interval between droplets. In the first half of hte injection period, the velocity of droplets which appeared later was higher than the velocity of droplets which appeared earlier. Large droplets with a relatively high number density were observed near the spray tip region.

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Exhaust particulate from diesel engines is affected by fuel properties, but the reasons for this are not fully understood. As a result there is a need to obtain a better understanding of particulate formation mechanisms and factors to be able to decrease particulate formation. This report investigates the amounts of particulate formation and analyzes thermal cracking and condensation polymerized components with a fluid reaction tube, thermal cracking apparatus and nitrogen atmosphere. The investigation shows that the temperature at which particulate formation starts depends on the properties of the fuel.

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It is important in determining whether we get low temperature heat release (LTHR) or not For instance, if we ran the engine with boosted intake pressure and low temperature, we could see LTHR but LTHR disappears if the same fuel is run with low intake pressure and high intake termperature. Thus whether we see LTHR in HCCI tests depends much on the operating conditions. The purpose of this study is to obtain fundamental knowledge about the effect of Intake gas Pressure and Temperature on HCCI combustion. The computational work is conducted using a multi-zone model and detailed elementary reaction mechanism. In this study, we use PRF which is the mixture of n-heptane and iso-octane.We can see the deference of the effect of intake gas pressure and temperature in HCCI engine between fuel structure.

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The purpose of this study is to evaluate the potential use of combustion phasing retard for reducing the pressure-rise rates in HCCI engines by going through numerical analysis with multi-zones modeling. The computations are conducted using the custom multi-zone version of the Senkin application of the CHEMKIN II kinetics rate code, and kinetic mechanisms for Di-Methyl Ether(DME), n-Butane and Methane. To objective of calculation with the multi-zones model is to examine the mechanism of combustion phasing retard to reduce an excessive pressue-rise rates. It is found that combustion phasing retard have the effect of reducing the pressure-rise rates and have potential for extending the upper load limit in HCCI engines.

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Regulated and unregulated emission components were measured for five Urea SCR vehicles under commercial using. One of them emitted high rate of NOx, PM and NH₃. A major reason of this deterioration would be HC poisoning, as NOx and NH₃ increased drastically in the case of other vehicles tested after long time idling, and as over 20 minutes of high load operating could recover the NOx emission performance. Global warming effect including N₂O were also investigated. From results, N₂O emission from urea SCR vehicles was quite high and total amount of global warming effect of Urea SCR vehicle was 20 % or more worse than it of an old vehicle of same sized without after treatment devices.

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A homogeneous charge compression ignition (HCCI) engine was investigated in an effort to improve the efficiency of 1kW class natural gas co-generation systems. A single-cylinder engine of 163cc was tested at 2050rpm. The effect of the compression ratio on HCCI combustion was investigated, as this is most important factor determining the operating conditions. The compression ratios were 27:1, 30:1 and 33:1. As the compression ratio increased, the intake air temperature could be decreased to below 75 degrees Celsius. The 1kW class natural gas HCCI engine could operate using only its own exhaust heat without requiring external energy. A natural gas HCCI with cooled EGR method was tried in order to increase the output and to improve the thermal efficiency. The cooled EGR increased the BMEP and improved the thermal efficiency. When the EGR ratio was 16.3%, the BMEP was 475kPa, NOx emissions were 170ppm(O₂=0%) and the brake thermal efficiency reached 31.0% (lower heating value), which was 1.6% higher than that in an SI engine.

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In hydrogen engine, high thermal efficiency and low nitrogen oxide (NOx) emissions are required. For the achievement of them, there are many possible combinations of injection pressure, injection timing and ignition timing that can be used in a system that injets the fuel directly into the cylinder. In this study, different combinations of injection and ignition timings were classified as three combustion regimes, and experiments were codnucted to make clear the differences in combustion characteristics attributable to the operating cinditions.

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A new technique of cross-correlation for PIV has been developed to more accurately measure the integral length scale for in-cylinder flow using a rapid compression/expansion machine. The new technique takes into account the rotational motion of gas blobs in addition to the translational motion in the calculation of cross-correlation between two consecutive images of an in-cylinder flow field. The measurements of integral length scale, turbulence energy and turbulence viscosity validate those calculated by a CFD code. Furthermore, temporal variation in turbulence viscosity during compression/expansion has been theoretically analyzed and the result explaines a general tendency of the experimantal results.

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The operation load of alcohol ignition interlock system on driving was measured by various driving scenes. It has been afraid that measuring the expiration while driving might make the driver anxious. Moreover, a change with the lapse of time of an expiration alcoholic density after non-alcoholic food and drink had been taken was measured. As a result, it is necessary to note that the engine might not be able to be started to detect alcohol immediately after drivers take food and drink including alcohol.

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In this study, differences of the fatigue characteristic of a bolted joint without a nut and the fatigue characteristic of a bolt/nut joint under transverse vibration have been investigated. Experiments were performed for those joints with same grip lengths to see the influence of the grip length on their fatigue characteristics. The results showed that the apparent fatigue limit of the bolted joint was smaller than that of the bolt/nut joint. The results also showed that the grip length has a direct influence on the lowest threshold for amplitude of transverse vibration force of both the bolted joint and the bolt/nut joint.

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This paper discusses a method to reproduce the rear-end collision risk based on data acquired Drive Video Recorder and to simulate the appropriate driver's brake operation. In this method, the appropriate brake including time and level is verified by an index called "Margin to Collision (MTC)". The result demonstrates that it is able to clarify the cause of accident or near accident from a viewpoint of driver's error of brake operation. Further, the arrangement of the relation between 420 brake conditions and ends is effective to evaluate both degree of the risk and appropriateness of driver's actual brake operation. Finally, the possibility to evaluate an active safety device was explored assuming two driver's conditions of reaction after automatic brake system.

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It is necessary for drivers to understand current and subsequent mode of driver-support system function adequately in order to prevent the misunderstanding and wrong use of the function. Display interfaces can accurately convey the modes to driver and may lead a driver to understand transitions of the modes adequately. This research aims to investigate each effect of visual and auditory display on driver's understanding of the mode transitions. The results of driving simulator experiment found that it was important to use both visual character and auditory signal simultaneously as to inform a driver of the current mode and increasing possibility of collision, especially when a driver was needed to avoid a collision. In addition, it showed that voice message was available when there were large margins for a driver to avoid collision with lead vehicle. The results suggest necessity of use of both visual and auditory display to inform drivers that it was necessary for them to avoid a collision in emergency situation.

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The effects of conversation task on drivers' visual behavior and detection performance were examined using a binocular gaze-tracking device and fixed-based driving simulator. The participants were engaged in various conversation tasks (mental imaging/mental arithmetic/shadowing) while following a lead vehicle. The results indicated that demands of conversation task, even if the contents are only slightly subjectively demanding, can affect a driver's visual detection performance. Follow-up study, by means of brain function imaging with fMRI (functional magnetic resonance imaging), suggested a conversation task that increment disparity angle of both eyes gaze direction also corresponds to the degradation of visual information processing at visual cortex.

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This study developed an algorithm for estimating sensor information at failure of the sensor on constituents of a platoon. The estimation is realized by using other vehicles' information in the platoon shared via inter-vehicle communication. For example, if a position sensor such as RTK-GPS on the leading vehicle fails, the position of the leading vehicle is estimated by motion information of the leading and following vehicles and position information and laser radar information of the following vehicle. The estimation algorithm is constructed using the Kalman filter and the algorithm is validated by simulation and experiments.

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Energy consumption in air conditioning (A/C) has a significant effect on overall vehicle fuel consumption. However, there are some technical problems to evaluate its quantitative effect. We conducted chassis dynamometer and on-road vehicle tests to measure fuel consumption. The vehicle tests included normal and high ambient temperature conditions with and without using air conditioning to identify its effects. The results show that it is necessary to evaluate increased fuel consumption due to high ambient temperatures to be taken into account the reduction in road load caused by the lowered tire rolling resistance and the increment in energy needed by A/C.

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We have developed a simulator for evaluating safety systems(STREET). In this paper, we focus on a driver visual behavior modeling to solve some assignments of traffic reproduction in street. This paper specifically shows an overview of a driver behavior analysis using driving simulator, and some issues for modeling of the driver behavior. Then, we employ a model-based approach for modeling the behavior. Finally, experiments show the proposed model is useful for representing the behavior.

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It is important to consider adequate designs of display interfaces in order to avoid drivers' confusions caused by a lot of information in vehicle when some driver support system functions were worked simultaneously. This research aims to investigate ways of selecting visual and auditory displays to facilitate drivers' adequate expectations of mode changes of system functions when two kinds of the functions are worked simultaneously. The results of driving simulator experiment found that it was important to use physical features of visual and auditory displays based on priority of each information in starting up two functions. The results also revealed that if two functions were worked to the same emergency situation, it is necessary to present visual and auditory displays for the only one mode of a function which had higher priority. On the other hands, if two functions were worked to the different situations respectively, it may be important to use visual and auditory displays on each function to show occurrences of two different events.

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We have been developing a Traffic Simulator called STREET which evaluates safety systems. To evaluate occupant's injuries in a traffic accident, it is important to evaluating safety systems. In this report, using the injury model, we tried to evaluate the occupant's injury observed in a real traffic accident in which a passenger car was involved. Consequently, we confirmed that the proposed injury model is available as an effective tool for evaluating the effectiveness of safety systems.

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The drivers' risk feeling during following and approaching to a lead car was quantified using a large scale driving behavior database of normal drivers in the real world which was obtained by the 100-Car Naturalistic Driving Study. Time to collision (TTC) was used as an index of drivers' risk feelings in those situation and the frequencies in different TTC levels during car following were quantified. It was also evaluated how often younger and older drivers were exposed to situations with a range of TTCs during driving.

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We evaluate the probability of stopping inside a railway crossing due to lead vehicle's sudden stopping when "stop" before entering the railway crossing is deregulated. Road environment of driving along the railway crossing was reproduced in a driving simulator. 30 drivers participating this experiment drove with various kinds of driving contexts, such as driving at low speeds or at high speeds while following a lead vehicle. The headway distances to the leading vehicle and drivers' reaction time to the brake lamp of leading vehicles were measured in the driving simulator experiment. Additionally, the deceleration from the application of brake pedal to the vehicle stop was collected from a driving behavior database. The probability of stopping inside the railway crossing was estimated based on the measured data. The results suggest that the probability of entering the railway crossing differs according to the driving speed range: higher driving speed and fast reaction time lead to low probability of stopping inside the railway crossing.

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We have proposed an instruction system for improving the parking operation by elderly drivers with the use of the trajectory of each driver at a parking lot. Experiments on the evaluation of the system with 18 elderly drivers were conducted. The results of comparison between the trajectories before and after the instruction show that the average precision of parking trajectories was improved. In addition, with questionnaire on the system concept, the use fee, the impression and so on, we classified the drivers into several classes by the method of the standardized driving style questionnaire. Results of the experiments and questionnaire show that the gender, a driving style, and use fee are the factors much influencing the proposed system.

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In recent years, the number of traffic accident shows gradual decreasing in severe injuries, whereas increasing the total number of accidents. It is necessary to investigate the drivers' behaviors in intersections since many traffic accidents occur in the area. During yellow light at signalized intersections, drivers occasionally fall into dilemma either passing through the intersection or stopping at stop-line. In this paper, using the drive recorder equipped vehicle, many incident data that occurred during yellow light has been investigated. Using the collected data, actual dangerous zone during yellow light is extracted. Because the zone is one of the targets for accident prevention, the obtained understandings are useful in considering measures for enhancing safety.

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Various computer-based simulation tools such as 3D-CAD systems and CAE are widely used to design automotive body structure at the early phase of design. Designers must search the optimal solution that satisfies a number of performance requirements by using their tools and a trial-and-error approach. In the three previous reports, a set-based design approach has been proposed for achieving design flexibility and robustness while capturing designer's preference, and its effectiveness has been illustrated with a simple vehicle side-door impact beam design problem and real vehicle side-door structure design. This report presents the applicability of our proposal for obtaining the multi-objective satisfactory design solutions by applying to an automotive front-side frame.

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This paper presents the development of tire contact patch measurement system under actual vehicle driving conditions and its applications. The contact patch of the tire/road interface is an essential factor regarding vehicle dynamics, tire-wear and so on. For many years the characteristics of the tire contact patch have been studied, however, those characteristics could not be confirmed under actual vehicle driving conditions. Therefore, we started to develop the tire contact patch measurement system. Since the pressure sensor seat was damaged under cornering or braking condition., the seat form has been redesigned so that the damage is reduced and the characteristics can be measured.

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Gear whine is a major source of unwanted noise in automotive applications. It is tonal in nature which makes it more apparent to the human ear than other stochastic noise mechanisms.
Prediction of gear whine behavior in automatic transmissions is a particularly complex problem where the conventional FEA approach precludes the rapid assessment of 'what if?' scenarios due to the slow model buidling and solution times .This paper will present an alternative approach, which is a fully parametric functionality-based model, including the effects of and interactions between all components in the transmission. It will be shown how the transmission error in all gear pairs can be predicted and how this can be used to excite the transmission model dynamically to predict the vibration response in any part of the system, including the housing.
Examples will be given to demonstrate the ability of this approach to rapidly investigate the system-wide effects of variation in parameters such as bearing pre-load and casing-bearing bore positional tolerance.

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A mono-tube type shock absorber incorporating the magneto rheological fluid (MR fluid) was designed to control the damping force electronically. The FEM magnetic field analysis was performed focally at the main part of the piston, where the magnetic field was controlled by an embedded coil. It is known that a saturated magnetic flux could be seen and also that the magnetic intensity at the orifice became maximum at a certain number of coil turn. The initial damping force and the coefficient of the yield stress of the MR fluid showed good linearity in accordance with the piston speed.

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In traditional three-way catalyst, precious metals have been dispersed on honeycomb structured materials such as metal or ceramics by wash coating technique. Recently, we have found and reported that precious metals were well dispersed in unique pores in the structured catalyst-paper, which was prepared by a papermaking method. In this paper, we will report the porosity of the paper structure for exhaust gas purification, since it was found that the catalyst-paper has meso-pores as well as macro-pores. The honeycombs prepared were two kinds of catalyst-papers, one is of high porosity [H-type;69%] and the other is of low porosity [L-type;52%] for monolithic catalyst. CO and NO conversions observed for H-type catalyst-paper were higher than those for L-type. For cold start performance, the HC combustion on H-type catalyst-paper was accelerated at lower temperature than HC combustion on L-type. It was concluded that the paper-catalyst could be applied to the actual catalystic converter.

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Recently, clean diesel engines are equipped with several variable mechanisms such as CRS, EGR, VG turbo, and VVT. Therefore, a huge variety of parameters must be optimized in order to improve the engine performance including engine efficiency and exhaust gas properties. In this paper, we focus on the improvement of the engine performance and robustness, which were achieved by the optimization method.

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It is well known that surface defects are decreased the fatigue strength. The cavitation peening method is in the limelight as a new possible surface refining method, which is a shot-less peening method and increases compressive residual stress. On studying the effects of the cavitation peening to the defects, the authors conducted an experiment using the smooth specimen with an artificial semi-circular slit and evaluated its refined surface characteristic and fatigue limit. The results obtained are:slit depth of the acceptable defect with the smooth specimen was 0.055 mm.

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Nationwide "ECO-DRIVE(Green Driving) Contest 2007" was held by the Environmental Restration and Conservation Agency and Ministry of the Environment. 534 companies took part in the Contest and 14,449 vehicles were registered. Through the analysis of their fuel consumption, it was proven that the participants had reduced CO₂ emissions by 1t-CO₂/year/vehicle through 'ECO-DRIVE' activities. In addition, some facts about the management system were revealed. Generally, the PDCA(Plan-Do-Check-Action) cycle is applied to the establishment of an environmental management system. However, while most of the companies maintained strict control of fuel consumption(the 'D'), they didn't develop their in-house system enough(the 'P'). Moreover, a lot of companies didn't carry out an assessment and review of the management system(the 'C' and 'A'). This result indicates that the promotion of 'ECO-DRIVE' activities will make an important contribution to the reduction of CO₂ emission in Japan.

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In order to study driver's behavior resulting in accidents and effectiveness of traffic accident-reducing active safety systems, a Driving Simulator was developed.
The Driving Simulator was equipped with a real vehicle cockpit, a visual 360-degree spherical dome screen, a turntable system, a hexapod system, a vehicle vertical vibration system and a XY-axis motion system with a movement range of 35m by 20m. This Driving Simulator enables to simulate an actual situation a driver experiences, as for example, driving at an accident-prone intersection.

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