EHD analysis has been utilized in the development of engine bearings, taking into account elastic deformation of the structure and solid contact. However, running-in process has not sufficiently considered irrespective of the importance for performance prediction. The relationship between the surface profile parameters of the Greenwood-Tripp elastic contact model and the amount of truncation at asperities is experimentally clarified. The amount of wear calculated by the proposed model, which updates the surface profile sequentially, agrees well with the experiment.

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CFD (Computational Fluid Dynamics) simulations are widely used for the research and development in the field of thermal fluidics, including internal combustion engines􀀑 Spray breakup models significantly affect the liquid film formation on the intake port wall impingement and mixture formation. However, there is no model for the atomization process under port fuel injection conditions with the plate-type multi-hole nozzles which have great atomization characteristics. The purpose of this study is to investigate the spray atomization process and predict the breakup process in multi-hole nozzle spray for port fuel injection. In previous studies, the authors have experimentally investigated the liquid sheet breakup process and droplet behavior of fuel sprays under port fuel injection conditions, and have modeled the droplet generation process based on the liquid sheet breakup theory. In this report, liquid sheet breakup model was modified and simulated the spray atomization process.

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In a spark-ignition engine with intake port fuel injection, fuel is sprayed into the intake port under flow conditions and atomized droplets flow into the cylinder, some of which adhere to the intake port wall and form a liquid film. The liquid film adhered to the intake port is a factor in combustion fluctuations due to cycle-to-cycle variations of the air-fuel mixture in the cylinder, as well as unburned hydrocarbons and soot emissions. In this study, a wind tunnel experimental apparatus simulated an intake port was constructed to understand the wall adhesion characteristics of fuel spray in the intake port during engine startup and cold startup conditions. Scattered light photography was used to observe fuel spray characteristics in static and flow conditions, and total internal reflection laser-induced fluorescence (TIR-LIF) was applied to analyze the wall adhesion characteristics of fuel sprays. As a result, in the static field, the spray interaction increased with increasing injection pressure, and the amount of wall adhesion increased. However, in a flow field, the spray follows the flow as the injection pressure increases, and the amount of adhesion decreases.

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In this study, author proposed motorcycle position measurement method that use image processing technology. Previous paper shows that an omnidirectional camera is useful to acquire angle information. In this paper, “Smart Pylon” is described as a new measuring equipment that keep correct position of an omnidirectional camera. Running test on a shape of the 8 figure with two smart pylons was carried out. The test vehicle is a small electric scooter equips with three inertial sensor units. Experimental results shows that the movies captured by omnidirectional cameras provide precision directional informations.

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This study conducted experiments to investigate the piston-connecting-rod coupled vibration for four types of connecting-rods with different I-beam section specifications. Furthermore, we analyzed the vibration-transmission and decay characteristics based on time-frequency-dependent combustion-noise-generation model for different connecting-rods and discussed the vibration characteristics on the engine outer surface. The results show that both the length and thickness of I-beam section of connecting-rod affect the piston-connecting-rod coupled vibration frequency, vibration-transmission efficiency, decay rate and the overall level of vibration acceleration. The change in vibration acceleration is mainly caused by the changes in vibration-transmission efficiency. For connecting-rods with same piston-connecting-rod coupled vibration frequency, an increase of thickness of the I-beam-section more greatly leads to a decrease of piston vibration and therefore to a decrease of the vibration-transmission efficiency.

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An order-based structural response function was developed as a simple intermediate index that indicates the quality of transmission characteristics when taking measures regarding transmission systems in order to enhance combustion noise quality. The index is the sum of the structural response functions from each cylinder for each typical order component, taking into account the different combustion timing of each cylinder. This enables identification of frequencies at which combustion noise is likely to be generated for each order. Comparison of the actual order-based structural response function and combustion noise showed that combustion noise quality deteriorates in frequency bands with high response amplitudes across multiple order components of the function. The results demonstrated that the function can be a useful intermediate index for structural measures.

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In recent years, commercial vehicles with leaf suspension has been demanded to be as quiet as passenger vehicles. Therefore, rear differential gear whine noise also should be reduced and not to be stick out from interior back ground noise. It is known that the gear whine noise is strongly influenced by resonance of leaf suspension and the resonance frequency varies widely. This paper reports control method of the vibration characteristics of leaf suspension by changing the contact position and stiffness between each leaf, which is the main factor of variation. Using this method, gear whine noise could be decreased effectively.

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In recent years, the achievement of the environmental quality standards in areas facing roads has been improved. On the other hand, many residents along arterial roads are still annoyed by road traffic noise. In this paper, focusing on roadside environments of arterial roads, we try to develop a hierarchical evaluation structure model of dissatisfaction with the roadside environments based on the answers to open-ended questions of residents themselves. By deciphering the evaluation structure model, we can clarify the reasons for the dissatisfaction with road traffic noise and measures to resolve them and comprehend the position of road traffic noise in roadside environments

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This paper describes the vibration phenomenon on vehicle motion from the perspective of energy propagation based on a two-degree-of-freedom vibration system. The energy transmissibility between the yaw and roll motions is analytically formulated by using their uncoupled natural angular frequencies, damping, and coupling characteristics. It is shown that the neutral steering character can be expressed by zero-energy transfer between the yaw and roll motion. The transmissibility is also useful to express the transient performance of the vehicle with under/over steering characteristics and the stable limit speed and so on. Finally, it is demonstrated that the transmissibility is useful to understand the transient performance under changing the roll stiffness and damping coefficient as examples.

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In the previous study, we developed a risk assessment test using a touch panel display, and attempted to measure self-monitoring ability based on the relationship between actual performance and its self-estimation. In this paper, in addition to this, we examined the relationship between the intention to compensate by velocity selection and the actual driving behavior on the road. In this study we increased the number of participants. In addition to this, a certified driving instructor rode along with the participants to evaluate their driving. Actual performance on the risk assessment test was uncorrelated with self-estimation of the test result. The self-estimation of the test result and the velocity considered appropriate for driving the same road again on the test were also uncorrelated. On the other hand, there was a significant correlation between the appropriate velocity selected on the test and the number of times the instructor rated the velocity as inappropriate. An analysis of variance of the two factors, with the adequacy of the self-assessment and the duration of the TMT-B time required as factors, revealed a significant interaction, with the group whose TMT-B time required exceeded 33.4 seconds (Median) and whose self-estimation deviated from the actual performance by more than 10% having significantly lower instructor driving score than the other groups.

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In this research, we proposed a method to artificially make a pedal misapplication on a driving simulator. Specifically, we used a method of remotely changing the pedal position so that the driver would not notice it. As a result, we were able to confirm the experimental participants who continued to step on the accelerator pedal without releasing it after pedal misapplication errors, as in recent accidents. It was possible to quantitatively investigate the driver reaction at the time of a pedal misapplication, which was difficult to observe in previous studies.

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Emergency Driving Stop System (EDSS), which can stop a vehicle when driver's sudden illness occurs while driving by pressing a switch, is beginning to be installed in vehicles such as large commercial bus etc. This study investigated the specification of the current emergency stop switches. Furthermore, the operation method of the emergency stop switch that is easy to press when the driver's sudden illness occurs was examined based on an ergonomic analysis. The authors evaluated the arrangement and shape of the emergency stop switch by questionnaire from the analysis considering the situation when the driver’s physical condition suddenly changed. As a result, it was found that the most optimal condition of the switch is when it is placed in front of the center console, with convex shape of 26-30 mm diameter. The characteristics make it easy to press the switch even when the driver’s eyes are closed and the posture is collapsed to the right due to sudden changes in physical condition.

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The steering reaction force characteristics in the on-center range were evaluated by subject experiments using a driving simulator. In these experiments, we analyzed correlations between the value of sensory evaluation and the physiological index. We found that sensory evaluation was possible for both evaluation drivers and general drivers using 38 sensory evaluation words. It was shown that CSI was correlated with the feeling of friction and viscosity for evaluation drivers. In contrast, SE was effective for the evaluation of the steering reaction force characteristics, which are unstable for general drivers. The electroencephalogram showed a common trend in both driver groups. The low beta wave index was effective for the evaluation of the steering reaction force characteristics, which allows the driver to concentrate on steering.

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The interaction between a Society of Automobile Engineers Level-3 automated vehicle and a fallback ready user is an important issue in automobile automation. We conducted a driving simulator experiment to investigate driver intervention during the system's emergency manoeuvre (EM) by steering when encountering an imminent collision risk during automated driving. As results of the experiment, many drivers intervened during the EM by steering, and drivers who intervened at a point when the lateral control force was particularly high tended to increase the risk. Based on the results of the first report and this experiment, we summarized the items that the system should consider when the driver intervenes during EM.

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We investigate the feasibility of gasoline engine boost pressure control using Non-linear Model Predictive Control (NMPC) in onvehicle ECU. First, we use a plant model based on the first-principles modeling with polynomial correction terms reduced in complexity by L1 regularization. Second, we adopt the barrier method as the constraint condition for optimization and propose a Pseudo-Barrier Function to improve the stability of numerical calculation. NMPC with the proposed method is implemented in an on-vehicle ECU, and we verify the feasibility of NMPC in an on-vehicle ECU.

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For the realization of Carbon Neutrality, hydrogen is considered to contribute to decarbonize various industriesand being focused. In transportation sector, hydrogen engines are studied in addition to FCEVs. Since hydrogenhas the property of being ignited more easily than gasoline, abnormal ignition is likely to occur. In this paper, themechanism of abnormal ignition peculiar to hydrogen is studied.

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This paper proposes the predicting methodology of the motor parts damage in the fatigue test when the motor case is excited randomly. In the past, we usually repeated trial and error in the actual test and fixed within the required fatigue standards. However, this developing process took much time. In this way, predicting the damage methodology was required widely.

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Dynamic wireless power transfer is widely studied to improve the short cruising distance and long charging time of electric vehicles. The receiving power control is very important to avoid the battery from overcharging. The authors have reported the receiving power control using pulse density modulation (PDM), however, the accuracy of the zero current switching (ZCS) is not good and the evaluation of the control performance is not deeply discussed. In this paper, the ZCS is improved using a comparator circuit and the control performance of receiving power control using the PDM is evaluated.

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In dynamic wireless power transfer (DWPT), maximum transferrable power is getting higher and higher to improve its commercial value. However, too much power transfer may cause damage in battery, especially when accompanied with regenerative braking. This work focuses on battery protection by on-board power control of DWPT. Active rectifier is chosen as a control device, and its controllability is evaluated in testing on electric vehicle running at low speed, which shows overshoot due to unmanaged switch timing. A new method, frequency deviation in active rectifier, is proposed as a countermeasure to the overshoot, and its effectiveness is validated in simulation.

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This study focuses on the deformation behavior of tread blocks and investigates its effect on tire road noise. Specifically, the strain, acceleration, and direct sound of individual tread blocks were measured and compared with the frequency response of tire road noise. Measurements were made by measuring the strain of the tread blocks using an image processing with a sequential phase-shift stroboscope, and by directly attaching compact-typed accelerator and microphone meters to the tread blocks to measure the acceleration and ambient sound field of the tread blocks themselves. The results obtained suggest that although the tread blocks are a source of vibration, the generation of tire road noise is not dependent on the vibration characteristics of the blocks alone.

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This paper deals with the possibility for construction of the database of the braking friction coefficient on the actual roads from the viewpoint of traffic safety. In order to construct a measuring device for road friction characteristics, a measurement algorithm is determined and the device is designed according to this. Next, the tires use for measurement are selected and the characteristics are measured using bench tire characteristic tester, and the measuring device is constructed based on this data. Finally, an experiment is conducted using this device, and the measurement results of the road friction characteristics are obtained.

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In the development of a pre-chamber jet combustion gasoline engine that improves thermal efficiency by realizing rapid combustion, an increase in high-frequency combustion noise in the 6-9 kHz band has become an issue. Such combustion noise is often an issue in the development of diesel engines, not gasoline engines, and is known to be caused by acoustic resonances in the combustion chamber. Therefore, the resonance modes of the combustion chamber of this engine were analyzed through calculations using finite element models and experimental modal analyses. As a result, it became clear that changes in the resonance frequencies occurring in conjunction with changes in combustion chamber volume affect the characteristics of the in-cylinder pressure, which is the cause of the combustion noise described above.

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This paper presents a method using energy transmissibility to discuss the vibration frequency-averaged response of a 2-DOF system. First, it is shown that the response of a simple 2-DOF vibration system composed of two masses and two springs can be simply predicted from the formula of the energy transmissibility. Next, previous studies on engine shake reduction are presented and the measures to reduce the shake response are reviewed, which measures are considering the coupling of bouncing and pitching motions and the employment of the hydraulic engine mount which are equivalent to dynamic dampers. It is then shown that these measures can also be derived in terms of the energy transmissibility. Finally, we argue that the energy transmissibility is useful for understanding vibration phenomena, designing vibration response, and enhancing new ideas for vibration response reduction.

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In this research, we study the effectiveness of images and point clouds for drivable area estimation. In previous approaches, the effectiveness of image and point cloud cannot be calculated and algorithm designers cannot interpret the role of image and point cloud. Therefore, we propose a network structure that explicitly calculates weights when integrating these features and analyze the effectiveness of image and point cloud. Experiments show that image information has more impact than point cloud for the recognition results. Especially, images features are used for recognizing surface of road, while point cloud features are used to recognize tall-objects.

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In a vehicle crash analysis which has a strong non-linearity, the prediction accuracy of machine learning (ML) using FE simulations data is considered to depend on the number of training data. In this paper, the correlation between the number of training data and prediction accuracy of machine learning was researched using a large number of parametric FE simulation data in the small overlap frontal crash with fractures in vehicle structure.

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Occupants with various body shapes and sizes can sit in various postures, which probably affects impact responses in collisions. In this study, we conducted finite element frontal impact simulations using male models with different body shapes and a female model in 3 sitting postures to examine the lap belt-pelvis interactions. Seating postures affected the risk of submarining due to changes in the pelvis angle and the overlap of the lap belt to the pelvis. The high BMI occupant model had fewer submarining cases due to a more effective overlap of the lap belt to the pelvis than the mid-size male.

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We developed a new type of hand support that enables passengers to keep their smartphones at shoulder height by supporting two points of an occupant's arm, an elbow and a back of the hand, to reduce carsickness and neck fatigue while passengers use their smartphones in a car. A field experiment using a minivan showed that the hand support reduced the rating of carsickness by almost half compared with a normal armrest. In addition, the hand support reduced neck fatigue and improved the ease of viewing the display of the smartphone while traveling.

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In order to collect fundamental data for preventing accidents caused by pedal misapplication of the elderly drivers, we measure the pedal operation in actual driving scenes on the same vehicle.􀀃 We use motion capture system and on-dash cams, and analyze the foot movement and the heel position, in the various driving scenes such as stopped, backed up and parked. The heel fixation group showed a greater distance from the center of the brake pedal and a smaller foot travel distance compared to the heel shift group.

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A numerical procedure using an artificial neural network (ANN) has been developed to identify the model parameters of 0-dimensional radiator heat balance models. This model parameter identification method includes two steps as follows. The first step is an ANN learning step. The second step is a computational analysis step to identify the model parameters using learned ANN. The model parameters to be identified are radiator-water thermal conductance as a function of water flow rate, radiator-air thermal conductance as a function of air velocity, and radiator heat capacity as a constant. The validation results indicate that the present method can be applied to identify model parameters.

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Real world fuel economy is affected by driving style, traffic flow, and other so on. Therefore, especially driving style improvement effect quantification has been difficult because the previous traffic condition can’t be clarified so far. This paper presents a possible quantification of the effect of users driving style improvement by using a traffic flow simulation with randomized traffic conditions and deviations. In this study, Traffic flow and driving style were modeled on simulation by measured data. This paper’s conclusion is that a good prospect is now in my current method to estimation of real world fuel economy effect by driving style improvement.

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A measurement system (SEMS) using NOx sensor, etc. was attached to a heavy-duty vehicle for the transportation business, and exhaust gas data and vehicle driving data during the transportation business driving was acquired for a long period of time. Based on these data, we investigated the driving conditions such as general road driving, highway driving, idling, etc. and the frequency of DPF automatic regeneration, and considered the relationship between the frequency of DPF automatic regeneration and the deterioration of PM collection performance.

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Regarding the calculation methodologies for future high performance computing (HPC) in variety of automotive research, quantum computing technologies are one of the promising candidate that could potentially instead conventional multi-core super computers. The functional material design, that idealize high performance electric vehicle or fuel cell electric vehicle, would be a suitable target for this novel HPC technologies. In this article, for the purpose of elucidating the practical possibility of quantum computer algorithms in future, we apply quantum gate simulations combining with classical molecular dynamics modelling to reproduce thermodynamic behavior of molecular composite materials. (Quantum gate simulator is as the exact simulator of quantum computer with no harmful quantum noise in limited small sized systems.) Liquid hydrogen, a potential candidate for hydrogen storage, are studied as the simplest case of this benchmark. Notable quantitative improvements of prediction performance in molecular dynamics modelling are obtained.

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A method was developed to enhance the bending strength of vehicle structural components by applying the work-hardening characteristics of steel sheet. When stamping the components, a corrugated shape is first formed, then the relevant part is flattened. Doing this lessens the reduction of sheet thickness and causes application of strain. The significance for yield strength of steel sheet obtained by these processes was clarified. When applied to hat-shaped components, the processes were demonstrated to have an effect on bending strength. It is considered that this approach will realize a reduction in vehicle body weight.

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In automotive wiper systems, nonlinear friction between the blade rubber and the windshield disturbs smooth motion, which causes tracking errors and increases operational noise. This paper proposes simple friction compensation based on linear feedback control with sign reversal of an integration. In simulation and experiment with a linkless wiper, the proposed method compensates for the nonlinear friction of the wiper motor and the blade rubber, and reduces the tracking error in particular for the slow motion after the wiper motion reverses.

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