There is a linear relationship between emitting pulse directions of bats and yaw velocities of bats flight. This paper shows that an emitting pulse direction coincides with the direction of the point which the bat is expected to reach some "look-ahead time" later. This implies that the linear relationship signifies an extremely simple "look-ahead model". Then, it is shown that the simple look-ahead model can express driver-operated vehicle motions with accuracy. Furthermore, it is shown that the unified model contains single adjustable parameter, "look-ahead time". The proposed simple look-ahead model is expected to be used for applying vehicle dynamics control.

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For an autonomous driving vehicle, it is important to generate smooth trajectory, which the vehicle can follow. Additionally, in complex environment like urban road, it is necessary to update the trajectory real-timely in response to environment information measured from on-board sensors. In this case, the trajectory must be taken into account with a connectivity of old trajectory. Therefore, in this study, we propose a trajectory generation method considering these assumptions. In this method, the trajectory curvature is parameterized by cubic spline, and optimal trajectory is generated based on non-linear numerical optimization method. From some simulation results, it was confirmed that our method can generate a trajectory adequately smooth and real-timely.

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This paper proposes a function extension of the forward obstacle avoidance system proposed by the authors in the previous paper so that it enables to avoid a moving obstacle like a pedestrian jumping out from the side of the road. In the newly proposed system, the avoidance trajectory is not derived against the current obstacle position itself, but against the predicted colliding position based on obstacle motion prediction. Then, the newly proposed system is examined by real-car experiments and its effectiveness is shown from the results.

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Pedestrian collision avoidance in urban environments is an important active safety technology to protect vulnerable road users and realize zero-traffic-accident society. This paper focuses on the intersection right turn driving situation which drivers need to negotiate pedestrians or bicycles near crosswalk region. This paper describes an autonomous collision avoidance by electric braking torque of electric vehicle. The intensity of braking maneuver is determined by the application of Potential Fields theory with considering occlusions in intersection environments. Finally, the effectiveness of the autonomous collision avoidance system is verified by the computer simulation.

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This paper describes the development of an algorithm for the real-time trajectory generation of a control target for an autonomous steering control system in the platooning system of a heavy truck. This algorithm is composed by the driver model, in which the risk potential is considered, as well as the vehicle dynamics model. The proposed algorithm was validated by a simulation that used the vehicle dynamics model with multiple degrees of freedom. In addition, the feasibility of the real-time processing for the control target was determined by a field test that loaded the algorithm on to the control hardware of the experimental vehicle.

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A human whole body FE model with muscular solid elements was developed to simulate 3-D geometry of each muscle and the muscle stiffness change for inputted muscle activation level. The model was validated against thoracic impact responses and the model responses showed good agreement with cadaveric test data. We investigated how occupant bracing conditions just before crashes would affect thoracic injury risks from frontal and side crash simulations using the model.

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This study proposes new injury predictors for concussive brain injuries, which do not contain any skull fractures. The new predictors describe characteristic features of rotational head motions due to impact, which can be calculated from 3-2-2-2 array head acceleration data on Hybrid-III dummies. CSDM (Cumulative Strain Damage Measure), which could predict concussive brain injuries, was obtained from a well validated human brain finite element model using concussive and non-concussive head acceleration data obtained from football games. The new predictors were also calculated using the data. This study found significant correlations between new injury predictors and the CSDM.

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The full body kinematics of the adult and elderly finite element (FE) models incorporating the thorax, lower limb and lumbar spine models were validated against the frontal sled test. The properties of the shoulder muscle were modified with reference to published thoracic belt loading table-top test results. It was found important to adjust the initial posture of the models to the Post Mortem Human Subject (PMHS) in order to get good agreement in the full body kinematics between the models and the PMHS.

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Intensity of the shock wave propagated in translational and radial direction was evaluated by brightness of the experimentally observed light emission and by calculated field in numerical simulation. Light emission from the shock wave was acquired from the optical observation with a high-speed video camera. Dependence of the brightness and pressure on the length of the shock wave were investigated. As a result, it is found that the brightness and pressure of the shock wave increases with shorting shock wave length due to convergence in cylinder.

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The reduction of belt vibration was studied. Research conducted previously had shown that belt vibration associated with amplitude fluctuations was generated by multiple frequency components centering on the natural frequency. Focusing on this phenomenon, the effects of the natural frequency of the belt, the fundamental order of amplitude fluctuation, and the excitation from engine were determined using simulations. The results indicated that increasing the natural frequency, increasing the fundamental order by using engines with a larger number of cylinders, and reducing the change rate of engine speed would be effective in reducing vibration.

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In recent year, the research on new ignition system with low temperature plasma for gasoline engine was reported by authors. In this study, the findings in which the low temperature plasma technology was applied to the autoignition promotion of the HCCI combustion were reported. The low temperature plasma igniter of a barrier discharge model was provided in the combustion chamber, and the ignition characteristics of the HCCI combustion by the low temperature plasma assistance was investigated.

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This paper describes the fuel properties, combustion characteristics and exhaust emissions of methyl esters of saturated fatty acid with 6 to 10 carbons in the molecule. The blend fuels (50/50 mass%) of three saturated fatty acid methyl esters (methyl caproate, methyl caprylate, methyl caprate) and methyl laurate as a base fuel are tested using a DI diesel engine. From experimental results, the blend fuel of saturated fatty acid methyl ester with lower carbon number has lower kinematic viscosity, pour point and smoke emission though longer ignition delay, as well as long chain saturated fatty acid methyl ester with lower carbon number.

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Observing the driver's behavior by reproducing traffic accidents and conflict situations are effective in investigating the causes of accidents. In previous studies, driving simulators were often used in reproducing accident and conflict scenes, but such systems had difficulties in reproducing in realistic situations. Therefore, a novel instrumented vehicle was developed to reproduce realistic traffic accident and conflict scenarios without the dangers of an actual collision. A person could drive the instrumented vehicle by viewing a frontal driving scene projected to LCDs which were fixed to the front of the driver. In this paper, we confirmed acceptability and controllability of the instrumented vehicle in driving. After that, three critical situations were reproduced by superimposing virtual objects on the frontal scene, rear end, angle and pedestrian. The results indicated that the instrumented vehicle might be effective to reproduce these critical situations.

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This paper proposed a new approach to evaluating collision risk of multiple car-following vehicles based on microscopic shockwave propagation theory. Macroscopic traffic flow “q” and density “k” are proved to be transformed into the microscopic variables such as inverse of time headway and that of spacing between vehicles. Speed difference weighted by the spacing between vehicles is proved to be the microscopic shockwave speed and used as the collision risk index of three-vehicle car-following. The applicability of the proposed approach is evaluated through real-world car-following data observed at a test track.

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HEV have regeneration capability, and can recover the energy on downward slope which stored on rising slope the as potential energy. This time we study the function of root guidance with energy saving for HEV, and have developed the expression of fuel consumption which include regeneration capability. To verify the effective of root guidance with energy saving for HEV, we set up the root which has altitude difference and ran the root measuring actual fuel consumption. Then we confirmed the effectiveness of root guidance for HEV

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CO₂ reduction is becoming one of the primary responsibilities for manufacturers. There is an urgent requirement to meet the conflicting demand of fuel economy and other vehicle performance. In order to meet the demand, the energy analysis of the whole vehicle for the optimization is becoming indispensable. In this study, multi-domain simulation using IEEE and IEC standardized Hardware Description Language was applied to the whole vehicle model and validated. The result was agreed to measured data. The accuracy of the fuel consumption was 1.1% errors for 3.5L V6 AT vehicle and 1.4% errors for Hybrid Vehicle at the LA#4 driving pattern. The multi-domain simulation is effective for discussing vehicle performance at planning stage. The simulation can be embedded real software. It is also effective as a SILS (Software In The Loop Simulation) for system control developing stsge.

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In a measurement of running resistant force, rolling resistance coefficient directly measured with coast-Down method is converted to the compensated value corresponding to standard atmospheric conditions. The compensation is prescribed to use an equation including ambient temperature when the coast-down test conducted. However, the validity of this procedure has not been verified enough. In order to investigate how temperature conditions influences the rolling resistance coefficient, vehicle tests on the proving ground were conducted under various temperature conditions. Furthermore, using advanced tire testing system which can control tire ambient temperature, the authors examined temperature influences on rolling resistance characteristics.

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This paper describes the development of a design method and process for quality variation. Quality deployment has been introduced as the tool for breaking down hierarchically vehicle performance/function to the level of parts characteristics. Combining Quality deployment and the concept of Taguchi methods enables the execution of designs that simultaneously reflect nominal design values and their variations. This approach is referred to as design response analysis and variation effect analysis. These tools make it possible to quantify the effects of variation in parts characteristics on the vehicle or system characteristics.

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Automobile air-conditioning system is indispensable for automobiles, and it is required the air-conditioning control system which actualizes thermal comfort and optimal energy use. In this paper, we firstly introduce the dynamical thermal environment model of the automobile that can be used directly for the design of the air-conditioning system. Then we adopt local SET* as thermal comfort index, and evaluate the thermal comfort of passengers quantitatively.

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Accident data of side collisions show that the head was the most frequently injured body region of child, and main sources of head injuries were the rear door and side window glass. It is not demonstrated how the child head contacted the vehicle side interior. From this study, the hard contact between the child head and the vehicle interior that occurs frequently in side collision accidents was reproduced in a car-to-small car oblique side crash test. Factors of a sled test were identified that reproduce the child occupant kinematic behavior in the SUV-to-small car side crash test.

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Fuels with uncertain property may result in the deposit formation inside the nozzle holes and it causes injection characteristics to deteriorate. In this research, engine tests with zinc added fuels, deposit analyses, laboratory tests and numerical calculations were carried out to clarify the nozzle coking mechanism. Initially, lower zinc carboxylate formed close to the outlet side of the nozzle holes by the reaction between zinc in the fuel and lower carboxylic acid in the combustion gas. In the growth phase, the amount of deposits at the inlet side gradually increased and the main component changed from lower zinc carboxylate to zinc carbonate by the reaction with H₂O and CO₂ in the combustion gas. Zinc concentration, combustion gas and the nozzle tip temperature have effects of deposit formation and the cavitation inside the nozzle holes has an effect of removing deposit.

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In this study, we combined a diesel engine with a hybrid system developed by our company (THS) for better fuel economy. However, the THS could not be utilized to its full advantage, since a conventional diesel engine has high NOx emissions in high load where fuel economy is good. Therefore, reducing engine friction, lowering the compression ratio, and a low pressure loop exhaust gas recirculation system (LPL-EGR) were examined to achieve both low fuel consumption and low NOx emissions over a wide operating range. Applying this system to a test vehicle, it was verified that the fuel economy greatly surpassed that of a conventional vehicle and that NOx emissions could be reduced below the Euro 6 regulations without DeNOx catalysts.

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The organic fraction of automotive exhaust particles is usually analyzed by Gas Chromatography (GC) or mass spectrometer (MS) after solvent extraction. However, it takes a long time to get analytical results. Progress in understanding and mitigating these problems is limited by the ability of existing instruments to provide real-time, size-resolved, quantitative measurements of aerosol mass and chemical composition. A number of measurement techniques possessing some of the required aerosol analysis capabilities have emerged recently. Real-time aerosol mass spectrometers aim to provide information on chemical composition of particle ensembles. Most of these instruments also provide information on particle size. An Aerosol Mass Spectrometer (AMS) with quadrupole (Q)/MS developed at Aerodyne Research has been designed to provide mass loadings for semi-volatile chemical componets that are present on ambient aerosol particles. AMS was improved to use Time of Flight (TOF)/MS exchanged from Q/MS for continuously measuring semi-volatile chemical compositions of automotive exhaust particles. AMS with TOF/MS is called TOFAMS. In this study, we would like to introduce analysis results of semi-volatile chemical composition of some automotive exhaust particles measured by TOFAMS.

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We developed an analysis method for steering and seat performances under dynamic environments. The movements of driver′s body were measured by using a motion capture system. The steering forces were measured by using the steering wheel with 6-axis transducers on the spoke, and the pressure distributions between the driver and the seat were measured by capacitive sensor mats. The interactions among driver, seat and steering wheel were analyzed by the software with a multi-body human model. The developed method was applied to a driver′s steering maneuver with an experimental 6-axis motion generator. Some of the results indicate an effectiveness of the proposed method.

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To achieve environmental performance and easy drive at the same time, many types of Automated Manual Transmission (AMT) for trucks & buses have been developed and evolved. However, AMT has a fundamental disadvantage. That is the torque interruption while changing the gear and it reflects on driver's feeling as a sense of Jerk/shock. To overcome this, Dual Clutch Transmission (DCT), that overcomes the past issue for the trucks & buses, was put to practical use for the first time in the world and has been installed in light duty truck.

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