The distance control assist system with an active gas pedal and a deceleration control was developed for the purpose of assisting a driver to maintain following distance to a lead vehicle. A field test was conducted to evaluate the effectiveness of this system. The result showed that, frequency and magnitude of deceleration by the driver were decreased, and, from the characteristics of TTC(Time to Collision)distribution, frequency of closing situations were decreased, that might contributed to the reductin of brake action by the driver. The AWWL(Adapted Weighted Workload)score on the NASA-TLX(Task Load Index)and the salivary amylaze activity score were also analyzed and the results showed the decrease of driver's workload by using the system.

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We suggest electo motion active suspension actuator of the rotary type that controls the movement of the roll, pitch, bounce direction of the vehicle. We clarified the effect of vehicle peroformance by using the skyhook control and the inertia control. We propose the example of active suspension actuator from the responsiveness nad consumption energy of the active suspension system.

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A urea SCR system was combined with a DPF system to reduce NOx and PM in a 4L turbocharged with intercooler diesel engine. Significant reductions in NOx were realized at low exhaust gas temperatures by increasing NH₃ adsorption quantity in the SCR catalyst. NH₃ adsorption control logic was developed for transient operations based on the NH₃ adserption characteristics. It has been shown that NOx can be reduced by 75% at the average SCR inlet gas temperature of 158 deg.C by adopting the NH₃ adsorption control in the JE05 made.

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In this research, new heat transfer engine model realizes the new way of Air/Fuel ratio controlling method. New heat transfer model uses two modeling methods which are a manifold heat transfer model and a lumped-mass heat transfer model which describes the heat transfer of the engine combustion. Heat transfer in intake port is one of the causes of A/F fluctuation, because the heated air in intake port expands and cuases charging efficiency variation which affects A/F fluctuation. A lumped-mass heat transfer model of vehicle gasoline engine and its feed forward A/F controller which use valve and port temperature is developed to eliminate A/F fluctuation.

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Diesel combustion is a complex process, including autoignition, premixed combustion and diffusion combustion. A novel TI(Time-scale Interaction) combustion model has been developed for simulating combsution phenomena with high accuracy from premixed charged combustion to diffusion combustion. This model is based on a reasonable combustion mode, taking into accout the characteristic time scale of chemical reactions and turbulence eddy break-up. Comparisons of measured and calculated heat release patterns and pressure histories showed good agreement for various operating conditions. The diesel combustion mechanism was analyzed under several fuel injection timings and engine loads using TI combustion model.

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A laser 2-focus velocimeter(L2F) with micro-scale probe was used for the measurments of velocity and size of droplets in diesel sprays near the spray center 15mn downstream from the nozzle. The injection pressure was set 70 and 100 MPa by using a common rail system. Droplets' light scattering was detected just after the spray tip reached the measurement position. It was confirmed that the rate of data-sampling should be increased to mega-hertz order for the measurement of narrow distance between droplets. With the increase in rail pressure, the droplet velocity increases and the droplet size dercreaes. It is understood that the droplet's number density increases with the rail pressure.

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To maximize the engine drive-ability and minimize the exhaust emission levels, oil companies have cotrolled the fuel distillations depending on the seasons and fuel distributed areas, but there is a possibility that the HCCI combustion characteristics change because of the c hange of the fuel composition. Though the crank angle at 50% burn(CA50), which is an important parameter to reduce unburned hydrocarbons, can be mechanically controlled, the mechanical controlling of high temperature heat release combustion period is difficult. The improvement of combustion characteristics from the standpoint of fuel composition is a purpose of this paper, and the interaction between fuel compositions and heat release patterns were fully investigated.

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This study investigated experimentally the effects of fuels stratification of Di-methyl Ehter (DME) which has large heat release in LTR and n-Butane which has smaller heat release in LTR than DME on Homogeneous Charge Compression Ignition (HCCI) combustion. With the four stroke single cylinder optical accessible engine, in addition to pressure measurement, chemiluminescence imaging was used as a means of visualizing stratified charge and evaluating local combustion characters. In some mixing methods, stratified charge reduced the maximum pressure rise rates during HCCI combustion. Chemiluminescence images showed that stratified charge, comparing to homogeneous charge, dispersed the start time of chemiluminescence.

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In recent years, for an automotive engine, there increases a demand of an environmental correspondence such as an exhaust gas performance and a high mileage, in addition to a demand of a high torque and a high output. For these demands, a CNG or LPG engine is one of the candidates for a low pollution engine. Thus, this paper proposes the high efficiency LPG engine system in which there is no return pass pipe to the fuel tank in the fuel pumping system. That is, by removing the return pass pipe that was considered to be impossible up to now, it is clear that the energy consumed by this return pass pipe is saved. In order to realize this system, the fuel supply by pumping should be precisely controlled so as to meet the fuel just required from the injector of the engine. Since the system is highly nonlinear, a sliding mode controller is used for this control purpose. The effectiveness of the proposed method is verified using simulation and experiments on the real system.

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We have proposed the LONG (Longitudinal Oriented Normative time Gap compensation) lighting system that enhances the conspicuity of motorcycles by enhancing the ability of oncoming drivers to evaluate the distance and speed of a motorcycle. It has been shown that the motorcycle with this system has almost the same conspicuity as a car by measuring critical time gaps. We state that both the layout of headlights and their number doesn't influence the conspicuity of the motorcycle with this system in terms of sense of distance and speed although the layout of the lighting system influences the conspicuity.

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The effects of Rh support materials and their loading amount on catalyst performance were investigated. As a result, Zirconium-based oxide (ZrO₂) showed better capability as a Rh support than alumina (Al₂O₃). Another finding was that the Rh dispersion rate in the washcoat is a key factor affecting the catalyst performance. The reasons for the superiority of ZrO₂ to Al₂O₃ are deemed as follows: 1) Even after severe thermal aging, ZrO2 can retain single-nano-size Rh particles by the SMSI. 2) On the ZrO2 support, Rh is more probable to retain metal state than on the Al₂O₃ support.

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The new catalyst technology,which makes it possible to improve the durability and reduce the loading amount of platinum group metals (PGM) for the three-way catalyst(TWC), has been developed. In the developed catalyst, the PGM particle is highly dispersed and strongly loaded on the ceramics support material to prevent their sintering. The diameter of the PGM particle in the developed catalyst was maintained to be lower than the conventional catalyst after the aging. The ceria oxide was used as one of the support materials for the developed catalyst, and its oxygen storage capacity and speed were increased as compared with the conventional catalyst. The developed catalyst has the excellent purification performance at lower PGM loading amount than the conventional catalyst.

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The driver's adaptive performance for the alteration of the steering system's characteristics is discussed in this paper. This report deals with the critical avoidance maneuver. Driving strategies on an initial stage of avoidance are the same even if the steering characteristics change. As a result, drivers feel high avoidance performance for quick gear ratio. On the other hand, too quick of a gear ratio is contrary to high controllability, but at the same time arranging the steering torque has the possibility to keep the high controllability. The relation was analyzed by using the driving simulator.

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A microscopic traffic simulator called STREET which evaluates the effectiveness to reduce traffic accidents by safety systems has been developed. The STREET simulates the behavior of drivers and traffic accidents caused by driver's error. We are proposing a detailed driver model which includes a cognition, a decision-making, and a operation behaviors. In cognition process, drivers recognize surrounding environment of vehicle affected by driver's characteristics which are described by combining the four typical parameters. And they decide the most appropriate driving maneuver affected by driver's characteristics accordingly. This decision model is easy to extend into complex conditions only by accumulating rules for each object.

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We have been developing a traffic simulator called STREET which evaluates safety systems. In this paper, we propose a method of reproducing the traffic accidents which are caused by driver's down-ability of non-driving tasks. In addition, we talk about an evaluation of the ratio of accidents and occupant's injury.

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From the viewpoint of coping with driving workload, "Workload Sensitivity Questionnaire (WSQ)" was developed to identify driver's characteristic. WSQ was constructed from a questionnaire servey and fector analysis which revealed 10 scales of the workload. In a survey on route choice preferences as one of driver's beharior, WSQ scales could make their differences clrarer than driver's conventional attributes such as age, gender, driving experience and habit. Furthermore since WSQ scales had good relationship to the preferences, it turned out that WSQ can explain differences of the preferences. These results show usefulness of WSQ toward understanding individual differences of driver's bahavior.

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By the results of computer simulation with orthogonal polynomial expansion of quality engineering performed on idling rattle of a manual transmission with backlash eliminator, the followings have been clarified. Using an additivity of factorial effects of first-order and second-order coefficients of orthogonal polynomial expansion and selecting signal factors separated into low and high oil temperatures, we propose a conditional inequality of design parameters that meet the objective values. By applying the aforementioned conditional inequality to idling rattle of a test transmission and an actual transmission, we could tune idling rattle levels to objective values with the design parameters.

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The possibility of wear reduction to the injector needle and of fuel rduction leakage from the injector is examined by using fatty acids and polymer type additives. The newly developed wear test equipment is used because of the implementation of an actual injector and DME as a fuel. A HFRR (High Frequency Reciprocating Rig) is also used to select a suitable concentration of additive. In this case, ETBE is used as a fuel instead of DME because of the similar SP value of DME. The concentration of fatty acids at around 300 ppm satisfies the recommended value (WSD<460μm) for diesel fuel. However there is some wear at the needle tip despite no evidence of wear at needle guiede. Therefore, the blend of fatty acid and polymer type additives is used to improve the wear resistance and increase the viscosity of DME to prevent a leam from the injector. As a result, the blend additives are effective for reducing wear at the needle tip and decreaing the possibility of leakage to almost nothing from the injector.

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NOx absorber is effective technology of after-treatment system to reduce the NOx emissions from diesel engine. We have studied after-treatment system with NOx absorber and combustion reactor. This after-treatment system has regenerator to supply the reductant as CO and H₂, and cleaner to purify the reductant passed through NOx absorber and harmful component generated at NOx absorber during the regeneration period. In this paper, we mentioned the characteristic of this after-treatment system, and we investigated the reduction ratio of exhaust emission from diesel enfine and additional energy ratio to regenerate NOx absorber in this after-treatment system.

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By applying high pressure direct injection of 20 MPa in SI hydrogen engines, high output power compatible to conventional natural aspirated diesel engine and low NOx emissions were achieved in addition to CO2 emissions and PM free which is the feature of the engine system. It was also predicted by driving mode trace simulation that NOx level of a quarter of the new-long-term regulation target by JE05 driving mode would be realized with combination of EGR and NSR catalyst(NOx Storage and Reduction catalyst).

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A technology to convert an existing gasoline MPI engine into an LPG engine with liquid fuel injection (LFI) system was developed. In this report, in order to achieve a good balance between an increase of the engine power and a reduction of the fuel consumption and the exhaust emissions in the LPG engine with LFI system, these performances were evaluated and ignition timing and A/F were optimized. As a result, it was clear that the LPG engine with this system possessed the great potential to improve these performances at high load condition. Moreover, this system could reduce exhaust emissions at partial load compared with the gasoline engine.

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In a LPG liquid-phase injection engine, the pressure in a LPG fuel supply system is controlled at some constant high pressure for anti-vapor-lock of a fuel by an engine heat. In this study, it is found out that at the low temperature especially at a high output of injection fuel follow, the pressure is not necessarily controlled at such a high pressure. Thus in this paper, the optimal pressure is determined experimentally and the experiments are followed to control the pressure at the lower optimal pressure for different outputs of the injection fuel follows for the different speeds of the engine. As a result, the exploited engine system is proved to be a fuel-efficient engine system. For the experiments, the fuel supply system without the return pipe and the regulator which is also exploited in our laboratory is used.

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From durability test, if we use conventional gasoline specified valve and valve seat for LPG liquid fuel injection system, we found that durability in unachievable. To improve this problem, it is more efficient to use conventional self-lubrication and high-hardness gaseous engine technology for exhaust-side. But we still found that we cannot solve this problem for intake side with the conventional technology. Because when injected LPG liquid fuel, it evaporates around the intake-valve and decreasing the temperature around it, and cannot built up oxidization layer, and consequence of adhesive wear. This problem can be solved surface treatment by soft nitride for the intake valve.

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The purpose of this study is to improve the transmitting efficiency of CVT by reducing pulley thrusts and preventing a rapid increase of belt slipping speed. The transition of belt slip from micro slip to macro slip was simulated by a spring-mass model. It was revealed that the power transmitting behavior could be expressed by the magnification factor. We proposed a new control strategy of pulley thrust using the magnification factor. The torque ratio was stabilized on around 1.0 and the transmitting efficiency was improved at any condition of input torque.

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The converting system has enabled on-board units to obtain information from the Internet. It is the world's first system to provide the Internet content to on-board units. Content providers can deliver more effective information to the on-board units by using extended RSS specification. This paper presents the details of the content converting system and the extended RSS specification and illustrates the potential of telematics.

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We developed new testing machine that enables fatigue testing in the high pressure hydrogen gas environment.And, we investigated the fatigue strength of quenched and tempered chromium molybdenum steel (SCM435) with this Machine. As a result, it was confirmed that the endurance limit of this steel has almost no influence by hydrogen gas though fatigue strength at low cycle side was remarkably decreased. We think that this fatigue testing will become a powerfulmeans of materials selection of the high pressure hydrogen system components of fuel cell vehicle.

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Cold-stamped door impact beams made of TS1180MPa grade cold-rolled high strength steel have been developed. The newly developed parts achieved both of weight-reduction and cost-reduction from former hot-stamped parts. Cold-stamping is successfully performed by developing the high strength steel with high ductility. To avoid delayed fracture, the map which shows conditions (applied stress, strain and hydrogen) of the steel that hydrogen cracking occurs was drawn, and the condition of the parts was set far from the hydrogen cracking region.

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Exhaust emissions from a vehicle under road driving condition is affected by the control state of ECU. This control state highly depends on the driving force of the vehicle. One of the contributing factors to determine the driving force is the hill climbing resistance, and for the evaluation of the resistance, it is necessary to take an accurate measurement of the road gradient. In this study, the measurement methods of the road gradient and the altitude with GPS, gyro sensor and height sensor are reported. The method of road gradient that was estimated from both pitch angle measured by a gyro sensor and vehicle gradient calculated by measured values of height sensors was invented.

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This study aims to regulate the sensitivities of various driving related measures that are used to assess the driver interfaces in driving support systems. In the tracking situation, generally, measures of drivers' operations were relatively sensitive than vehicle location measures, and it was confirmed the measures that revealed significant differences during driving on a simulator were also valuable during actual driving. In the detection-response situation, ratio of collisions detected interface difference only when the situation had relatively high urgency. However, operation measures, e.g., reaction times to press brake pedal, and glance behaviors were sensitive to detect differences even if no-collisions were observed in less urgent situations. Subjective ratings and glance behaviors revealed generally good sensitivities. Based on the obtained results, primary and secondary importance of driving measures were discussed.

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