First, the effect of roll axis layout on vehicle lateral motion is explained by basic dynamic equilibrium. A high roll axis enables a four wheel vehicle to roll inward in a turn. The high roll axis vehicles are compared with a conventional low roll axis vehicle by full vehicle model simulation for emergency obstacle avoidance. Double lane change test and fishhook test simulations are executed. Besides flat road condition, tramping road condition which has a disadvantage for high roll axis vehicle is applied. In consequence, the high roll axis dose not affects emergency obstacle avoidance performance on both these conditions.

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This paper investigates and considers the effect of steering torque hysteresis for steering behavior. Simulations have performed by torque controlled drive-vehicle closed system in 3 types of course trace tasks. Simulation results have proved smooth increasing characteristics of steering torque hysteresis are good for steering settlement in steady state cornering and precise steering, and also have proved difference of steering damping and steering torque hysteresis.

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The relation between disk brake squeal and pad stiffness is analyzed. Pad stiffness is commonly measured as static pad stiffness. On the other hand, dynamic pad stiffness, which is evaluated by exciting a pad at the frequency and vibration amplitude that cause brake squeal, is measured in this report. The study shows that brake squeal is influenced by dynamic pad stiffness, not static pad stiffness. Hence dynamic pad stiffness is taken into account for FEM analysis, and the analytical results of brake squeal agree well with the experimental results.

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The adult and elderly FE thorax models reported at 2009 JSAE Spring Congress could achieve less biofidelity in chest impact, one of the reasons for which was assumed to be less biofidelic bone models other than ribs developed with few biomechanics data published. In this study, the sternum and the costal cartilage models were updated referring newly published test results. Incorporating these bone models, the thorax models showed improved response in chest impact.

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In order to build a useful and comfortable in-car human machine interface systems, the information presentation method should be easy to understand (low mental workload). Moreover, the driver should be able to respond with ease to the presented information (low response workload).We are trying to establish an evaluation method of the mental workload independent to the response workload. Here, we present the results of our trial using brain waves measurements (Eye Fixation Related Potentials). We focus on the relation between P3 latencies and drivers response workload compared to mental workload in a task involving eye movements.

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This paper proposes a new velocity guidance system with haptic HMI in the aim at realizing more economical and smooth traffic by using information from Intelligent Transport Systems (ITS). The proposed system uses accelerator pedal reaction force as the information presentation. The system consists of two parts mainly: the Desired Pedal Stroke Calculator (DPSC) and the Pedal Reaction Force Characteristic Controller (PRFCC). The purpose of this paper isevaluating the effect of guidance by reaction force with Driving Simulator (DS). The evaluation experiment is carried out with six subjects who have difference in age and experience. As a result, the questionnaires show that the reaction force guidance has effectiveness in reducing workload in information processing, while not bothering the drivers during driving, and the experimental results show the feasibility of drivers′ operation guidance by the haptic interface with pedal reaction force.

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Developing a driving state estimation framework is important to improve the core technologies of individual adaptation technique. This paper proposes a scientific method to detect deviated driving by using individual reference driver behavior model. First, the model treats the car-following state as a spring-mass-damper system. Next, to diagnose the driver, the deviated driving is detected from the distribution of deviation of each state variable compared to the reference model. The driver model parameters are identified at every certain sampling time duration for the diagnosis function. Finally, the proposed algorithm is implemented in the test vehicle to examine its feasibility.

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In Japan, the issue to reduce the CO₂ emission made by the automobiles has become very serious. As one measure, the eco-driving has been evaluated to be effective and promoted actively by the central and local governments. The eco-driving means changing the driving styles to be much more economically and ecologically. It is necessary to propose the effective driving styles in order to promote the eco-driving. However, regarding the effects of the eco-driving, there are quite different research outputs from the different studies. By considering most of the studies up to now had been based on the computer simulations and there were only a few had been based on the real situation, we conducted a group of test run on the public roads under the normal traffic conditions using passenger car. This paper is to report the results of our studies.

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The Low Pressure Loop (LPL) EGR system is well known as an effective technology to reduce NOx emission and fuel consumption. A system that combines both LPL-EGR and a NOx storage reduction (NSR) catalyst will be able to achieve further lower emission levels. However, this combined system has to overcome the issue of combustion fluctuations due to the recirculation of rich gases coming from the NOx reduction control. In addition, the time required to re-circulate rich gases vary in accordance with the engine operating conditions. This paper proposes a countermeasure based on the usage of Air-Fuel Ratio (A/F) sensors and a simple recirculation delay model.

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To reduce vehicle development time and cost, it is necessary to predict parts temperature accurately in the advanced study stage. But it is difficult to calculate the temperature of exhaust system in a short time. So we developed an efficient approach to predict parts temperature by considering the effects of radiation, convection and heat transfer, using the loosely coupled computing method.

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The improvement in fuel consumption was kept down to a compression ratio of 14:1, because of lower friction losses. However, low compression ratio engines have issues of poor starting performance, white smoke, and combustion instability in low temperature environments or in high altitude conditions. Through this study, we managed to keep the fuel mixture temperature high. Large numbers of fuel injection nozzle holes, multi-pilots with good mixture spreading, and large diameter of combustion chamber have been evaluated as being effective countermeasures. These methods have realized a compression ratio of 14:1.

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In this study, numerical analysis of diesel combustion and particulate matter formation and oxidation in wide intake O2 concentration condition was conducted by 3D-CFD code KIVA-3V combined with Finite-rate elementary chemical reaction and phenomenological soot model. This numerical analysis could predict in-cylinder pressure, rate of heat release, NOx emission and Soot mass under wide intake O2 concentration condition with high accuracy and there is possibility that predicts smokeless low-temperature diesel combustion. In addition, this report showed the effect of intake O2 concentration on Soot formation and oxidation.

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The effect of changing compression ratios (ε=14~22) on fuel consumption has been studied. As results of experiment, ε=18 can improve fuel consumption without remarkable deterioration on exhaust emissions. With ε=18, the high boosted and high EGR rate diesel combustion which has the feature of the maximum cylinder pressure = 28MPa and high degree of constant volume ηgl was experimented at full load for the improvement of fuel consumption. Finally, the minimum fuel consumption (BSFC=181.2g/kWh, ηe=46.3%) was achieved by these engine specifications.

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Evaluating active safety measure effectiveness using accident data, it is sometimes hard to estimate the scenario leading to accident. The effectiveness of Collision Mitigating Brake and Electronic Stability Control are quantitatively analyzed using Hiyari-Hatto (near-miss incident) data recorded by drive recorders equipped on taxies in three regions. Hiyari-Hatto data are collected only from taxies and contain different properties from accident data. This paper discusses the problems and the countermeasures in utilizing Hiyari-Hatto database.

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To establish a more effective method of injury prediction is an important concern related to enhancing the survival rate and/or reduction of permanent disabilities of injured persons in automobile accidents. The injury prediction method based on the accident reconstruction methods using mathematical simulations (multi-body, FEM) is proposed, and the applicability of the method is discussed. Furthermore, the methodology for the injury risk prediction method based on the results of the mathematical simulations is likewise discussed.

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An electric power steering system (E.P.S) is replacing a hydraulic power steering system recently. Estimation of rack bar axial force during stationary steering is indispensable for system design, because not only the capacity of the motor, but also the layout of suspension and the system depend on maximum rack bar axial force. In order to estimate the accurate rack bar axial force, new method is developed based on precise moving tire contact patch distorted figure. Additionally, the rack bar axial force fluctuation factors of tire trajectory prescribed suspension layout is investigated.

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Vehicle pull is a phenomenon of straight-driving performance that causes customer dissatisfaction. This paper describes the vehicle pull improvement utilizing the Quality Variation Control Process which is developed by Nissan to improve quality variation. Design countermeasures and key characteristics to be controlled in the manufacturing process are clarified by conducting the design response analysis and the variation effect analysis. Appling the countermeasures to a new model in US market the vehicle pull nominal value and variation improvement is confirmed.

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In-Wheel Motor drive units have been developed since 1990's. The motor output has 10 times more than the first assist drive unit in the rear for FF vehicle. But it is still much difficult to install a motor in the space of the wheel. The development of a new drive unit has been started for good installability of a motor in many kinds of suspensions. The reduction mechanism is the combination of planetary gears and counter gears that enables to offset the motor axis from the tire axis. Thus, the motor can coexist with suspension arms and brake caliper. The increase of unsprung mass with 40kW motor incl. cooling and lubrication system is +23%.

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In this study, we conducted hydrogen gas fueling and defueling cycling tests to examine the thermal behavior in hydrogen storage tanks under actual use conditions. As a result, it was confirmed that the gas temperature in the tank varied depending on the initial test conditions such as the ambient temperature of the tank and the fueling gas temperature, and that the gas temperature tended to stabilize after several gas fueling and defueling cycles.

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We conducted in-vehicle effect measurement for a system that prevent dangerous driving, by stimulating the drivers′ sense of competition by displaying their safe driving scores in a ranked format that were determined by their velocity and following distance data. The results on road experiment showed that the system we proposed effectively promoted the participants to drive with large time gap and this suggests that the system has potential to have the drivers drive safely.

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To improve the readability of the text typography on a multi information display (MID), the quality engineering was applied. We aimed at the deriving the optimum condition and the factors that influenced readabilities most efficiently. The sentence of the reading object on the display was indicated intermittently, that was simulated driver's behavior to watch the MID while driving, and the time-length to read was measured. As a result, the optimal condition which is able to be read at a steady rate of time even in different visual situations, has been found, quality engineering is a verification method for focusing on the items that had to be examined emphatically.

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A new generation horizontally opposed gasoline engine was developed in order to adapt to strengthening global environmental regulations. The engine was completely reviewed and redesigned from its main structures. Reduction of fuel consumption is done from two perspective combustion improvement and friction reduction. Combustion improvement was achieved by introducing a new dual AVCS, TGV, EGR cooler. The new engine included friction reduction achieved 11.8% fuel consumption gain.

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