In the present study, we perform the systematic survey for the effect of friction boundary on deformation behavior of coned disc springs subjected to axial load. A simplified method for predicting the load-deflection curves, including hysteresis due to friction at edges, is proposed based on the equivalent of energies and the friction law. The validity of the present method is then verified by the comparison of FEM analysis results obtained under various conditions. Furthermore, the resonance characteristic of coned disc springs subjected to axial forced vibration is examined by using the proposed method. The effect of friction boundary, i.e. frictional damper, is examined for several frictional conditions and forced amplitudes.

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In this paper, a new linear suspension actuator with a suspension control law based on a novel energy-based optimal control method is proposed for self-powered active suspension systems. Since the effective inertia of such actuators along suspension motion axis directly affects the suspension performance, proposed actuator is specifically designed to reduce this effective inertia. Anti-parallel relief valves are utilized in design aiming more effective shock input force suppression. Hybrid actuator is controlled by a novel optimal control method. Overall system is evaluated by a hardware-in-the-loop simulation. Results reveal the superior performance characteristics of the proposed hybrid actuator and suspension control law both for random roughness road and smooth road with a road bump.

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Some tire manufacturers have commercialized efficient tires called "Eco-friendly tire" which improve fuel economy. However, measurement methods of tire loss affected by driving force, which occurs during transient mode driving, have not been established, therefore, it's difficult to properly analyze and evaluate the efficiency of those tires.
Solving this problem, the advanced testing system for tires which conducts dynamic tests under various conditions of revolution, torque transfer, and perpendicular load equivalent to those of mode driving was developed.
Using this system, different type of tires were tested both in static and dynamic operations and tire loss was analyzed.

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This research deals with influence of tire characteristics and of rider's lean angle on characteristics of two-wheeled vehicle. At first, the influences of two parameters calculated by front and rear camber thrust and of lean angle of a rider on characteristic of the two-wheeled vehicle are analyzed. Next, influences of rider's lean angle on slalom are analyzed using the quasi-steady state analysis. It is found that these have strong influence to the sideslip angle of the vehicle.

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This paper describes the development of a vehicle model for a steering control system on the platooning system of a heavy truck of the energy ITS project, which is targeted at CO2 reduction and energy saving. For a vehicle model used for some control systems, not only reproducing the state quantity of a real vehicle accurately but also the parameter identification method and the real time calculation are the important factor. The proposed model is a physical model with minimum dimensions and it describes the planar motion of the vehicle. In the vehicle model, the sideslip characteristic and steering characteristic were obtained from the measurement data by a steady-state turning test performed using an experimental vehicles for obtaining the equivalent cornering stiffness. The vehicle model corresponded to the measurement data of the experimental vehicle. Therefore, it was confirmed that the vehicle model had a high performance in the identification accuracy.

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In this paper, probability of survival (Ps) on road accident in Japan was analyzed. A total of 5,005 road accident injury data from Japan Trauma Data Bank (JTDB) were used to estimate Japanese Ps model by using logistic regression modeling. These were statistically significant relation between Ps and RTS, ISS and age score. The Ps model has shown a good correlation with actual survival rate. In addition, Ps model by road user type was estimated. It was found that Bicycle accident patients with sever head injury are classified to high risk group based on Ps analysis. From the result, Ps analysis has a good possibility for injury prediction of post crash safety.

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Finite element human models (FE model) are developed worldwide to assess injury mechanisms caused by collisions by using numerical simulations. Bio-fidelity of the model is important in order to clarify the injury mechanisms with the model. In this report, a full body human FE model to assess injuries in an event of front impact is presented. Chest of the model was validated based on experimental results from component tests and table-top tests with Post Mortem Human Subjects (PMHS). Moreover, kinematics of full body of the model has been evaluated by results of impact sled tests with PMHS.

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A human FE model with muscular bar elements including skeletal and muscular parts of whole body was applied to frontal impact simulations with a vehicular sled model. Muscle activity was estimated based on EMG data obtained from volunteer tests and was assigned to the muscle models in order to simulate occupant bracing conditions in pre-impact braking. In this study, we investigated how occupant bracing conditions could affect occupant motions and impact forces on the human body during frontal impacts.

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A human finite element model for low speed rear-end impact analysis was developed. This model can reconstruct not only whole body motion but cervical vertebral motion to investigate intervertebral deformation based on the hyposis that neck pain is evoked by local strain on the intervertebral soft tissue caused by hyper translation and rotation of cervical vertebrae. The human model was validated with the published rear impact test data using Post Mortem Human Subjects (PMHS) and the model response showed good agreement with the PMHS response.

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To measure brain activity directly during the execution of driving operations, an experimental vehicle was fitted with a functional near infrared spectroscopy system and measurements were made of the blood flow changes in the prefrontal cortex. Evaluations of the relation between blood flow changes and driver workload were also made. Driver workload was defined as the task of driving on narrow roads with different levels. These levels of difficulty corresponded to subjective workload using the NASA-TLX. The results revealed that the levels of driving task difficulty significantly effect the change in oxygenation concentration. In addition, the oxygenation concentration in the right lateral portion was found to be significantly higher compared with that of other portions. The results suggest the possibility that brain activity in the right lateral portion of the prefrontal cortex is related to driving on narrow roads.

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For realizing automatic parking system, there are many important issues that are recognition of circumstance, estimation of own position, selection of destination, path planning, vehicle control and so on. In this paper, we propose the method to create the scanning map of the obstacles using lidar and to estimate own position by matching the obtained scanning data in real time to the created map. We also show the result of the position estimation by proposed method using the scanning data of the parking lot.

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This study proposes the control method for vehicles to pass through an intersection by cooperating with each other on contact with the intersection-traffic control which manages the schedule of vehicles to enter the intersection. And a vehicle control algorithm for reaching the intersection at the scheduled time is also proposed. The proposed vehicle control and intersection-traffic control are validated by experiments using electric light vehicles.

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In previous paper, it was revealed that ignition timing for homogeneous charge compression ignition engine in which ethanol-gasoline blends are used is advanced compared with gasoline's one under a certain condition. And a factor was analyzed by using chemical kinetics simulation under constant pressure and adiabatic condition. In this paper, effects of in-cylinder temperature history and residual gas on ignition timing were examined by the chemical kinetics simulation in combustion chamber condition to further clarify the difference in ignition characteristics between ethanol and gasoline.

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In gasoline engines, fuel spray adheres and impinges on the wall of intake ports and cylinder. Adhered fuel affect exhaust emissions. It is important to understand the behavior of impinging on a wall for decision of injector position and spray properties. In this paper, the tendency of breakup droplet became clearly with the behavior of impinging by measurement of the droplet size on variety of impingement wall angles.

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The new method to measure in-cylinder flame propagation and mixture distributions has been developed. These distributions are derived from analyzing the time history of flame spectrum CH* and C2*, which are detected by the spark plug type sensor having multi-optical fibers. The validity was confirmed that the measurement results of this method correspond to the high speed flame visualization and LIF measurement results. Additionally, this method was applied to the analysis of cyclic combustion fluctuation of DI gasoline engine, and the availability was confirmed.

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The premixed charge compression ignition combustion combined with EGR and high pressure fuel injection at the early stage of the compression process favorably reduce the emissions from direct-injection diesel engines. In this study, numerical analysis was conducted to investigate the above-mentioned combustion regime by using the fuel spray model that considers the collapse energy of cavitation bubbles formed in the fuel nozzle based on the computational fluid dynamics code, KIVA-3V.

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In-Direct Injection (IDI) two-stroke cycle compression ignition engine with DME low pressure electronically controlled direct injection system is proposed to increase engine output power. The brake mean effective pressure of 1000kPa was achieved by this engine system. When the cross-sectional area of connecting passage of the divided-chamber increased, the ignition delayed, combustion duration became long and maximum combusition pressure reduced because the swirl in sub-chamber was weakened. The engine was stably operated for DME injection timing between 12 and 2 deg. ATDC and combustion process was strongly influenced by the cross-sectional area of connecting passage regardless of DME injection timing.

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Recently many issues related to automotive engineering, such as the environment and energy problems have gained attention. These social-related issues are giving impetus to the adoption of urgent measures such as alternative fuels and new combustion techniques for the internal combustion engines. In this context, dimethyl ether is thought to be a potential alternative fuel, as it has lower overall pollutant emissions and better economy. The purposes of this paper are to examine the combustion properties of DME flames at elevated pressure up to 2.0MPa. Laminar burning velocities of DME-air mixtures were determined experimentally over a wide range of equivalence ratio under the various pressures of 0.1MPa, 0.3MPa and 0.5MPa, employing spherically expanding flames. In addition, the combustion properties of DME flames at elevated pressure up to 2.0MPa were examined to clarify the dynamic behavior of the effect of initial pressure corresponding to the practical engine condition.

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In order to obtain higher thermal efficiency in future Dimethyl ether (DME) engines, it is necessary to consider the effect of high pressure injection. However, the influence of high pressure injection on a DME engine has not yet been understood. In this study, the influence of injection pressure on the brake thermal efficiency was examined using a common rail type DME injection system with injection pressures up to 100 MPa, and influencing factors of brake thermal efficiency and the drive work of the high pressure pump in the injection system were also investigated. These results demonstrated that the effective injection pressures to obtain better brake thermal efficiency.

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The purpose of this paper is to study PM reduction mechanism of DMC blended fuel in DI diesel engine. A direct sampling system was used to obtain spatial and temporal information of combustion products in a combustion chamber. Experiments were conducted using gas oil and DMC blended fuel. The experiment data was arranged with isoconcentration maps. As a result, maximum concentration THC and SOF reduce, the fuel spray volume of DMC blended fuel which is low boiling temperature was slightly increased than gas oil.
In addition, DMC blended fuel have oxygen. Therefore, local excess air ratio increased.

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Backwards reaction tracking method proposed by the authors was applied to define the cross reactions. When alkane and alkane are mixed, RO₂+R'·RO+R'O and RO₂+R'O₂·RO+R'O+O₂ was found to be the possible cross-reactions. In alkane-alkane mixture, however, the influence of these cross reactions is negligible. Chemical kinetics of nC₇H₁₆ - iC₈H₁₈ mixture was analyzed. When the portion of iC₈H₁₈ is increased, ignition delay until LTO, τ₁, increased, and ignition delay from LTO to thermal ignition, τ₂, decreased and temperature at the end of LTO, T_LTO decreased. By replacing iC₈H₁₈ with N₂, it was clarified, that iC₈H₁₈ addition prevents 2-step OH reproducing paths causes longer τ₁, and higher T_LTO causes longer τ₂.

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Precise combustion control becomes more important to achieve lower emissions and fuel consumption. A piezo-driven diesel injector equipped with needle-lift sensor was newly developed for detailed analysis of the relation between fuel injection and combustion. Exhaust emission test and combustion visualization analysis were conducted the injector in order to clarify why lower smoke level was achieved using after-injection with short interval. Visualization results showed that fuel spray of after-injection was ignited immediately, and combustion region of after-injection was separated from that of main injection. Consequently soot oxidation was promoted, and smoke emission was reduced.

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It is reported that the particulate matter in exhaust gas is reduced when oxygenated agents are added to diesel fuel, but the inhibition mechanisms are not established. To explain this mechanism, we investigate the amount of particulate formation and analyze thermal cracking and condensation polymerization components with a fluid reaction tube apparatus and nitrogen atmosphere. As a result of experiment, Starting formation temperature, and PM concentration depends on the fuel properties, and the combustion temperature of PM.

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To evaluate effect of washcoat in SiC-Diesel Particulate Filter (DPF) on the initial PM filtration efficiency, we measured particle number concentration in diesel exhaust gas downstream of SiC-DPF by EEPS. The amount of washcoat materials was changed. Results show that the particle number concentration is largely reduced in washcoated DPF. Thus, it is considered that soot layer is easily formed during initial filtration process. Depending on PM diameter, different effects of washcoat are observed. This is because PM filtration mechanism is different in the range of PM size.

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It is predicted that the amounts of both N₂O and CH₄ having greenhouse effect in vehicle exhausts will increase in real-world drive because of the reduction in catalyst temperature and so on. Then, in order to investigate this phenomenon, the on-board FT-IR gas analyzer, which is possible to continuously analyze both gas compositions in road driving test, has been developed. The road tests were conducted by installing this analyzer in gasoline vehicles. With those test results, the increase of both N₂O and CH₄ emissions exhausted from gasoline vehicles were analyzed and the cause of this phenomenon was investigated.

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For the reduction of green house gas emission in transportation sector, an eco-driving has been promoted. Though the eco-driving will have the reduction effect of CO₂ emission, the influence of the eco-driving on air pollutant emission such as NOx is not clear. In this study, the effect of the eco-driving on real-world emission has been analyzed using the diesel freight vehicle with the on-board measurement system.

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We have investigated the display conditions for drivers to notice the existence of human in infrared images. In practical use, resolution of infrared camera is more effective than conventional LCDs. It has shown around 6 pixels corresponding to human's face height on the photo-cells are the threshold level to know that existence, which is expressed in ppf (pixels per face height) here. It is also shown the part of the head or the upper part of the human body plays an important role to notice that existence. We used positive infrared images to avoid seasonal temperature difference in the experiment.

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Induction hardening is widely used for chassis components to add compressive stress there to control crack growth, since wear resistance and fatigue fracture strength are highly required. Therefore, it is crucial that the defect influence is examined with being compressive residual stress on the parts.
In this report, the relationship between crack depth and compressive residual stress was evaluated using cylindrical specimen and torsional fatigue test. Consequently, the test results followed CAE obtained in advance. In future, it is necessary to make this method applicable to the product design to improve
vehicle safety performance further.

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Our company works on the improvement of fuel efficiency by driving behavior in addition to the improvement of the fuel efficiency of the car.
This time, we developed the ECO pedal system which was characterized in tangible user interface by the accelerator pedal additional force for driver's guide of fuel economy, and adopted it in a new car.

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Exhaust and evaporative emissions systems have been developed to match the characteristics and usage of THS II plug-in hybrid vehicle (PHV). Based on a conventional hybrid vehicle, The PHV features an additional external charging function, which allows it to be driven as an electric vehicle (EV) in urban areas, and as an hybrid vehicle (HV) in high-speed/high-load and long-distance driving situations.
To reduce exhaust emissions, the conventional catalyst warm up control has been enhanced to achieve emissions performance that satisfies Super Ultra Low Emissions Vehicle (SULEV) standards in California in every state of battery charge. In addition, a heat insulating fuel vapor containment system (FVS) has been developed using a plastic fuel tank based on the assumption that such a system can reduce the diffusion of vapor inside the fuel tank and the release of fuel vapor into the atmosphere to the maximum possible extent.

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Effects of impurities of fuel, which are worried to mix during producing and delivering when DME fuel for vehicles is put on a market, on DME fuel lubricities were investigated by special modified HFRR (High-Frequency Reciprocating Rig). Adding 100 ppm of fatty acid type lubricity improver in DME could be reduced the wear scar diameter 400 μm below. Water contamination of around 500 ppm and above increased wear scar diameter clearly. Methanol contamination did not affect on DME fuel lubricity.

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Sub-freezing, cold start is one of the important issues of FCVs. The main cause of the voltage drop during cold startup is clogging the catalyst layer by the product water generated on the cathode side. The transfer phenomena of the product water during cold startup has been investigated and it was found that to improve water transfer in the membrane was effective for cold startup. The improvement has been adopted to the membrane of the new FC stack and the FCV equipped with the stack has been confirmed its enough cold start capability for launching in the real world.

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Cold start was a major issue for fuel cell vehicles. It is known that if the oxygen or hydrogen supply is limited, the concentration overvoltage increases and the conversion efficiency decreases, thereby increasing the amount of waste heat generation. The rapid start-up operation method takes advantage of this characteristic to increase waste heat generation, directly warming the fuel cell stack more quickly. With this procedure, the system can increase its waste heat generation more than 16.5 times above normal.
This operation method was applied to Fuel Cell Hybrid Vehicle (FCHV) with modification of circuit topology and air supply control logic. The FCHV achieved the performance to start in 30 s from a fuel cell temperature of -15 °C and also demonstrated cold start capability in temperatures down to -30 °C.
In this paper, the concept of rapid start-up operation is introduced and examples of vehicle application are explained.

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The nitrogen components (NO, NO₂, N₂O and NH₃) analyzer has been developed utilizing Quantum Cascade Laser (QCL). The QCL can emit coherent light in a mid-infrared region where these nitrogen components have strong absorption. This laser optics configuration can give us a super fine resolution of the mid-infrared spectrum. Therefore, utilizing this spectrometer it is possible to reduce the interference caused by the spectral overlap of co-existing gases in engine exhaust gas. In this report, improvement of the response time of NH₃ measurement has been attempted. Moreover to achieve wide measurement ranges two detectors with two different light path lengths have been used.

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The occupied bandwidth of an UWB radar system is more than 450 MHz, in such wide frequency bandwidth there are restrictions in order to share with other wireless systems. In this paper, the regulatory status in Japan is reported by referring a report issued by the Ministry of Internal Affairs and Communications (MIC), which has started to investigate about interference effect to existing wireless systems from December 2006.

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This paper examines effectiveness of representing fuel consumption information for improving fuel economy and investigates its influence on performance and situation awareness of driver. An experiment has been conducted to compare two type of indicators: (1) instantaneous fuel consumption meter and (2) average consumption meter. The result shows that the fuel consumption rate was improved when a driver used instantaneous or average fuel consumption meter while the driver's situation awareness was degraded by the use of the instantaneous fuel consumption meter.

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In this study, we develop a simulation technique to predict sound isolation performance in the low frequency range below 500Hz so that the technique can support a study to improve the quality of sound generated from exhaust system. This technique consists of two steps: (1) prediciton of sound pressure sound pressure distribution in sound field outside vehicle utilizing infinite element, (2)prediction of sound pressure in passenger cabin loading the pressure obtained in the first step. We demonstrate the first step which is crucial in the technique can provide results with good accuracy and the practical computation time.

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There are two methodologies for the transfer path analysis (TPA). One of them is force-based TPA, which is theoretically clear and has been used widely. The other is acceleration-based TPA, which was recently proposed and of which software has been commercially released already. In this paper, structural vibration is focused on to investigate the meaning of the acceleration-based TPA firstly. Secondly, on the basis of the interpretation, the possibility of a new generalized method is referred to, where force and acceleration are both considered as system inputs. Lastly, the qualitative characteristics of input contributions calculated by the method are discussed and then shown using simple simulations.

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Recently, the demand on an improvement of comfort in the automobiles has increased. When it is considered the car as a room, the space planning of the seat arrangement influences the comfort greatly. In this research, the seat arrangement with rotating seat for improvement of passenger comfort is proposed. To rotate seat inside the room of the car can increase communication of passenger. To rotate seat outside the room of the car can produce private space. Therefore the comfort can be improved. In this paper, the sensory evaluation is performed. This result shows the effect of comfort-improvement.

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Despite several studies regarding the evaluation of the criteria for arousal level reduction, the method of predicting the reaction time (RT) delay and its relationship with the criteria was unclear. Therefore, we evaluated the arousal level reduction by developing a new measurement index for the eyelid, named the “eye opening rate.” Herein, we investigated the correlation of RT with the eye opening rate and other indexes (blink rate and eye closure rate) for evaluating arousal level reduction. As a result, the significant correlation between eye opening rate and RT was observed for all the participants. This suggests that it is possible to predict the RT delay by measuring the eye opening rate while driving.

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The particle size distribution and number density at engine-out were measured by changing EGR rate and injection pressure in a single cylinder diesel engine. This engine was adopted high-boost, wide-range and high EGR system and high injection system. The particle size distribution and number density were measured at BMEP=0.9MPa as medium load and at BMEP=0.2MPa as light load at 1200rpm, which are high frequently used for JE05 transient test mode. Brake specific particle number emissions were 4.3×10¹³#/kWh at BMEP=0.9MPa and 1.1×10¹⁴#/kWh at BMEP=0.2MPa.

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