Vibration characteristics of a CVT metal belt were evaluated in terms of vibration transmission characteristics of two bearing sections for the DR and DN pulleys. While the resonance phenomena occured in the inter-axial vibration on conventional belts at 800-840 Hz, they did not occure on the evolutionary type. It was clarified that this resonance phenomena is caused by the additioal spin by the spinning motion of the element in the string section.

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Stable supply of oil for lubrication and cooling into drive units has become an important issue. We focused on the shafts of transmissions installed in automobiles and applied the technology of current automatic transmissions. In this study, the behavior of oil lubricating a pipe simulating a shaft rotating at high speed in a multiphase state dominated by centrifugal and agitation forces was evaluated through experiments. The pipe geometry was varied, and the oil discharge behavior and discharge flow rate ratio were evaluated. The discharge velocity of lubricant in the pipe and the discharge behavior of oil from the discharge hole with changes in pipe velocity were evaluated in three patterns, and their correlations were evaluated.

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The impact of charging condition with wide operating SOC range on degradation of LFP-type lithium-ion batteries was analyzed. The battery degradation was evaluated from the two perspectives which are SOH (state of health) and SOS (state of safety). It was observed that repetition of charge-discharge in conditions with quick charging under low temperature causes a rapid decline in battery capacity and increased risk of thermal runaway. Chemical analysis for disassembled cells was also conducted in order to support the rationality regarding the risk increased.

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Aluminum is the main material of cell case of prismatic lithium ion battery, but using nickel electroplating steel sheets is expected to improve safety, increase volumetric energy density, reduce costs, and so on. In this study, prismatic lithium ion batteries using a nickel electroplating steel plate as a cell case was fabricated, and thermal runaway propagation was evaluated, it was confirmed that thermal runaway time was extended.

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Dynamic wireless transfer (D-WPT) of electric vehicles (EVs) will significantly extend the range of EVs, thus increasing the potential for electrification of passenger cars. For convenient usage in the real world, D-WPT systems must be light, affordable, and accessible by mixed traffic. The authors’ study group has proposed a 150kW D-WPT system. In this study, mechanical and electrical characteristics under different circumstances were verified. The ground assembly (GA) was buried in asphalt for loaded truck treading test, and distortion and durability were confirmed. Electrical characteristics were compared with asphalt, vehicle snow, and rain.

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To assess the impact of fuel cell output control methods on the lifetime of a fuel cell in the fuel cell hybrid test train, we developed a predictive model for the fuel cell output voltage degradation. We utilized the predictive model to evaluate the differences in fuel cell output control methods that affect the lifetime of the fuel cell. And we studied the effects of degraded fuel cell on the vehicle performance and the fuel economy.

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The present study uses an Ising machine to solve a multi-constrained, multi-objective optimization problem of car-body structure design. While Ising machines require explicit formulation in the context of QUBO, vehicle performance, such as impact performance, is generally a black box. Therefore, we apply FMQA, which approximates the black-box function using FM and solves QUBO for optimization. In FMQA, the difficulty lies in the appropriate weighting of evaluation functions and the suppression of local search. In this study, we propose their resolution and compare our method with conventional optimization methods to verify the usefulness of quantum (-inspired) computing in real problems.

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As the diversity of prime movers continues to grow, the applying the component-TPA to the finished off-road vehicles such as construction machinery and agricultural machines is ongoing to realize the modular design. In this study, the effects of the nonlinearity of accelerance in the forced vibration system excited by the prime mover and the condition number when identifying the blocked force using the inverse matrix method have been investigated.

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The previous study presented a method to predict road traffic noise using a model derived from a single vehicle test, focusing on three components: tire/road noise, powertrain noise without load (mechanical) and with load (dynamic). This study focuses EV model that tire torque noise, generated during acceleration, is treated as a dynamic component with load-adjusted coefficients. The necessity for re-measurement with different tires highlights the need for a theoretical model. The study introduces a new theoretical model for tire torque noise, validated through its impact on exterior vehicle noise, demonstrated with a passenger car, enhancing noise prediction accuracy and efficiency.

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Using one year of insured accident data, the accident rates for Toyota and Lexus vehicles equipped with the third-generation Toyota Safety Sense and Parking Support Braking (based on around view camera) systems are calculated. Each of these results are compared with the earlier generation systems. As a result, it was confirmed that rear-end collisions with vehicles and accidents with stationary objects in parking areas are reduced compared to the earlier generation.

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The goal of this study is to predict pedestrian injury severity using a deep learning method based on dashcam video for Advanced Automatic Crash Notification System (AACN). The developed injury prediction model detected pedestrians according to their injury severity from dashcam images based on pedestrian behaviors during an accident, and correctly predicted their injury severity. However, false detection and no detection were observed for accidents such as nighttime, rainy weather, rare behaviors, and children.

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This research aims to reveal the characteristics of injury levels of drivers who caused pedal misapplication accidents, analyzing drivers’ age groups, drivers’ injury levels, types of accidents, road types, and drivers’ maneuvers. The results indicated that single-vehicle accidents frequently led to fatalities and serious injuries among drivers, with a higher incidence among elderly drivers, and often occurred in parking lots. These accidents commonly involved collisions with houses, walls, guard fences, parked vehicles, and other structures. Furthermore, the incidence of fatalities and serious injuries was higher in cases where collisions with poles or where vehicles fell off.

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Data on the NOx purification performance of copper-based zeolite SCR catalysts installed in vehicles that comply with the 2016 exhaust gas regulations was collected continuously by conducting chassis dynamometer tests and actual road driving tests as the accumulated mileage increased. Using these, the NOx purification rate, space velocity, etc. were used as analytical indices to consider the NOx purification performance of the urea SCR catalyst during the use process. As a result, when the NOx purification performance of the urea SCR catalyst decreases during use, it was found that the NOx purification rate decreased significantly as the space velocity increases.

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The evaluation of delayed fracture resistance is one of the major issues to the application of high strength steel sheets to automotive parts. We are proposing a method for evaluating delayed fracture resistance using the four-point bending test specimen. The purpose of this study is to clarify the effect of the baking treatment on the delayed fracture resistance of the ultra-high strength steel sheets. The material used in this study is a martensitic steel sheet with a tensile strength of 1470MPa. The delayed fracture resistance was investigated by conducting an immersion test using a four-point bending test specimen in a solution of 0.1%NH4SCN+McIlvaine buffer for 96 hours. It was confirmed that the baking treatment was effective in improving the delayed fracture resistance. The hydrogen content decreased and the carbon segregation in the prior austenite grain boundary increased by the baking treatment. It was clarified that the mechanism of delayed fracture resistance improvement by the baking treatment was the reduction in the amount of hydrogen absorbed into the steel sheet and the increase in grain boundary cohesion strength through the increased carbon segregation at the prior austenite grain boundaries.

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In this study, fatigue tests were conducted on spot-welded tensile-shear joints made of 590MPa-class high-tensile steel sheet as the base material, with various load ratios in the load range after a single overload being applied, and the threshold load ratio at which the effect of the single overload disappears was experimentally determined. The threshold load ratio was linearly related to the repeated load range. The effective strain range after a single overload was obtained using the threshold load ratio. It was shown that the effective strain range can be used to evaluate fatigue life with and without a single overload.

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In this study, the load transfer method of a steel battery housing was investigated. Normally, an undercover is used to protect the lower part of the battery pack, but in this structure, the undercover is utilized to transfer the load of the steel battery pack to the front, rear, left and right of the vehicle.

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We investigated the effect of load frequency using thermoelastic finite element (FE) analysis on Lap fillet arc weld joint commonly used in automobile parts. To simulate the thermoelastic effect, we developed a stress field-temperature field thermoelastic FE analysis technique that calculates the heat transfer of heat generation and heat absorption according to compression and tensile stress. The calculated stress distribution showed a good agreement with thermoelastic stress distribution measured using an infrared ray method. Moreover, we verified the accuracy of estimating the fatigue limit obtained from the point of sudden increase in dissipated energy by infrared measurement.

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Paraffinic fuel has been received much attention and often studied its promising potential as a future low-carbon and cleaner emissions’ diesel alternative fuel by its less soot characteristics. However, the effects of each fuel property, which varies in a wide range along with other properties variation, on diesel combustion and emission characteristics has not been clearly revealed yet. That could make the preferrable fuel design difficult. This study investigated each fuel property effect on combustion and exhaust emission characteristics by adding several new fuels test to the previous study, and discussed the difference in combustion phenomena by utilizing combustion visualization technique.

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Fuel spray injected into diesel engine cylinder develops with entraining ambient air. Air entrainment flow surrounding the spray side boundary interferes with that of adjacent sprays. And the spray interferes with piston wall and develops along the wall surface. Then the spray interferes with the adjacent sprays developing along the wall surface similarly. In this study, the effect of each interference on combustion was investigated by using a single cylinder engine.

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To improve the thermal efficiency of diesel engines, increasing the compression ratio by extending the stroke length without combustion chamber volume reduction has been suggested as an effective approach by engine combustion CFD simulations. Therefore, experimental evaluation of extended stroke specification about indicated thermal efficiency improvement effects was carried out using a single-cylinder test engine. As a result, extending the stroke length is verified to be an effective approach to improve indicated thermal efficiency, as cooling loss is significantly reduced in high load conditions. In low load conditions, reduction of exhaust loss contributed to improve indicated thermal efficiency.

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In order to improve the power transmission efficiency of the MID ratio of the evolutionary metal belt, the type of contact between the pulley and the element was changed from linear contact to point contact. It is revealed that the torque transmission efficiency is improved by changes in the torque transmission distribution by the element and the ring.

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Recently, electrification of the powertrain is required for heavy-duty vehicles as well. In this study, a heavy-duty PTO (power-take-off) type parallel hybrid electric vehicle (HEV) model for fuel economy simulation is developed using the OpenModelica which handles the Modelica language to analyze its fuel economy impact by the electrified powertrain. The second report first presents a method for identifying each component model using data measured on a chassis dynamometer. Next, the accuracy of the developed model is verified. Finally, the fuel economy impact for different hybrid powertrain control strategies is analyzed using the developed model.

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This study reports the development of a method for calculating an Order-based FRF using CAE analysis with a finite element model (FEM) for enhancing the sound quality of engine combustion noise. An FEM was created from a power plant model equivalent to a bench vibration test, and it was confirmed that an Order-based FRF similar to the experiment could be calculated. In order to simplify the analysis model, verification was carried out, so the main motion system model was omitted and a method of inputting the excitation force to the main bearing was considered. As a result, it was found that an Order-based FRF equivalent to the actual machine experiment could be calculated with only the power plant structure model. By using the CAE analysis method constructed in this study to calculate the Order-based FRF, it is possible to identify the frequency band and mode of concern for sound quality deterioration and to consider countermeasures at the pre-prototype stage.

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This paper proposes a neural network classify car driving sounds based on multiple psychoacoustic metrics such as Time-frequency analysis, correlation between carrier frequency and modulation frequency. The data classification contribution of each parameter and the characteristics of the sound for that parameter are extracted by visualizing the data classification basis of the neural network.

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In order to study the relation of safety level between automated driving vehicle and human driver, analysis of driving behavior of human drivers is necessary. In this research, the experimental test by using the driving simulator was conducted in some dangerous traffic scenes, which were selected from the accident patterns assumed to occur in the root where the automated driving demonstration on the public road and mixture traffic with other traffic participants were planned.

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In powertrain development, in addition to performance design that maximizes the reduction of CO2 emissions, efficient development process with no rework and MBD (Model Based Development) are also necessary. Furthermore, fuel economy performance that assumes actual usage environment is required, EPA (U.S. Environmental Protection Agency) 5-cycle which evaluates various environments as fuel economy performance evaluation has been applied. The performance prediction considering engine temperature is essential in the EPA 5-cycle, and it is necessary to assume MBD from performance design stage to performance verification stage. This study summarizes migration from conceptual model described in previous report to detailed model and its utilization in vehicle development process.

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An accurate prediction of engine coolant temperature is important for applying simulation technology to vehicle development under various environmental conditions. In particular, the Co-Simulation environment proposed in this study requires high prediction accuracy of the thermal plant model, because it has a controller model and a performance plant model corresponding to the engine coolant temperature. The thermal plant model integrates a power unit and its associated heat exchangers. However, because of fluid behavior around radiators in a radiator fan operating conditions is complex, there are issues with representation using a 1D model. This paper proposes a model enhancement method that considers airflow through the clearance between the radiator and surrounding components.

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In four-wheeled vehicles, an imbalance between front and rear roll moments and roll stiffness influences steer characteristics through changes in tire vertical load. However, few studies have logically analyzed the effect of body rigidity on vehicle handling characteristics. Especially for three-wheeled PMVs (Personal Mobility Vehicles), no research has been conducted. Therefore, this study first organizes the effect of body rigidity on tire vertical load in four-wheeled vehicles using a simplified body rigidity model. Based on this, we examined the influence of body rigidity on vehicle dynamics in a three-wheeled PMV with two front wheels and one rear wheel equipped with an active tilting mechanism. The results suggest that an optimal torsional rigidity around the vehicle’s longitudinal axis may exist for transient tasks in real-world scenarios, such as obstacle avoidance. Although no clear optimal value was found in simulations conducted using a vehicle dynamics analysis tool, it was observed that obstacle avoidance capability saturated at around 70% of the torsional rigidity typical of monocoque structures, confirming the impact of torsional rigidity on vehicle dynamics and validating the effectiveness of using a simplified body rigidity model for dynamic analysis as conducted in this study.

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