The partial oxidation phenomena of post injected fuels in diesel engines are the topics in this paper. In engine experiments, a dual fuel engine was operated by HCCI operation with n-hexane port injection, and the inhomogeneities of temperature and equivalence ratio in cylinder were changed by the after-diesel-fuel DI operation. The heat release and CO and HC emissions were measured and the progress in partial oxidation of post injected fuel was evaluated. Further, a CFD simulation was introduced, and the ignition mechanism of post injected fuel was analyzed. The results suggest that the inhomogeneity of incylinder temperature is an important factor that determines the progress in partial oxidation of post injected fuel.

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Spray characteristics of diesel mini sac nozzles are unsteady during initial and end stages of injection. In this paper, modeling the effect of needle lift on sac internal flow and high dispersion spray due to sac vortex flow during low needle lift at the initial and end stages of injection are reported. The injection velocity with the sac pressure and the sac vortex energy and the injection droplet diameter generated by the liquid film thickness of high-dispersion spray are estimated. The model results were compared with experimental results obtained from fuel spray visualization. The results show that the proposed injection model can reproduce the unsteady dispersion characteristics of spray during low needle lift.

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A prototype of a newly invented two-way roller clutch was produced, its operation was verified, and its performance was measured using a test machine consisting of two servo motors and torque meters. The clutch could transmit power without slipping within the capacity range of the test machine. The force required to disconnect the actuator was in good agreement with the calculated value, and it was experimentally confirmed that the clutch could be clamped in as short a time as 0.1 s with a differential rotation of 100 rpm.

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The behavior of commercial trucks is subject to large fluctuations in vehicle characteristics due to significant changes in the payload. The selfdriving controller needs to maintain a specified tracking performance against such fluctuations. This study proposes a control system to improve tracking performance during turning under large variations in vehicle characteristics such as vehicle weight and center of gravity position. The truck model is hierarchically divided into a kinematic model and a dynamic model, considering the variations in load and tire force in the dynamic model. Then, we construct the system which applies NMPC and feed-forward gain scheduling control to each model. Thus, the effect due to loading are reduced while the dimension of the computationally intensive NMPC is suppressed. In addition, the NMPC predictively decelerates the truck to prevent deviation from the path by incorporating an evaluation of the magnitude of centripetal acceleration into the stage cost. Finally, we verified the performance of the present controller using a multi-body dynamics simulator. As a result, we confirmed the effectiveness of the deceleration generated by NMPC in preventing deviation during cornering, even when the load is increased from empty to the maximum loaded state and the center of gravity position is shifted significantly. It was also confirmed that highly accurate tracking control was achieved whereby the maximum lateral deviation was fewer than 0.15 m.

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Semi-active suspensions can control damping force and provide a good ride comfort. However, it requires dedicated sensors on four wheels, which increases cost and tuning man-hours. Therefore, development of sensor value prediction technology based on CAN data has been promoting to achieve low cost sensorless semi-active suspension system. This paper describes the suspension control method to replace the sensor function to the neural network by getting data of the vehicle with the sensors as a teacher data, and training. As a result of verifying with the data in the test course, the neural network could almost predict the sensor value.

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Since the past year, Hanshin Expressway Company has been studying a method to evaluate the contact risk due to lane changes, targeting straight sections of the expressway without merging, using a wide range of vehicle trajectory data observed from certain positions. Now, as the next step, we propose a method to evaluate the contact risk during merging by probabilistic expression and classify them based on coordinated driving behavior, targeting the vicinity of merging.

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We developed a method to detect bumps/Humps, which are small bumps placed on the road, using an in-vehicle stereo camera. Therefore, we developed a CNN discriminator that uses depth-height waveforms obtained from 3D shape measurements as input. We investigated the performance and processing time of a configuration that can be scaled to the processing capacity of an embedded device.

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This paper deals with a lane-keeping control under a tire blowout. A steering assistance system under a tire blowout situation is proposed that assists the driver’s steering behavior by the steering assistance torque after the occurrence of the tire blowout. Driving simulator experiments were carried out to confirm an effectiveness of the proposed steering assistance system. The experimental results showed that a lateral deviation of the vehicle was able to be reduced by the steering assistance system. Then, the risk of a lane departure under the tire blowout was able to be reduced by the system. On the other hand, it was also confirmed that increasing the assist torque might lead to conflict between the driver and the assistance system.

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We analyzed the muscle activity focused on a changes of lower limb motion during pedal operation. When the moving directions of a pedal and a ball of the foot were matched, the linearity between a soleus muscle activity and force exerted on a pedal was high and the muscle activity of a soleus muscle was low, consequently the easy driving feel was obtained.

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The purpose of this study was to investigate the accidents caused by pedal missteps in the elderly. We applied the method of examining missteps by driving simulator in the previous report to the elderly. When the foot position was displaced during braking, the elderly failed to correct, and multiple cases of misstepping were confirmed. Additionally it was considered that it is not recommended for both elderly and nonelderly people to step on the floor with the heel attached to the floor because the lateral movement of the foot is insufficient when the heel is attached to the floor during braking.

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The camera that monitors bus drivers’ glance behavior and pose must be placed behind the steering-wheel to avoid obstructing driver’s view. The problem is that the steering-wheel occludes part of driver’s body, which would reduce the accuracy of driver’s pose estimation. In this study, we propose an approach to estimate the steering-wheel area by using semantic segmentation and remove this area from the image by using Image Inpainting. Our experimental results showed that the accuracy of pose estimation could be improved and using Pluralistic Image Completion (PIC) for removing the steering wheel had the best results. In addition, the experimental results showed that adjusting the variable z of PIC before driving can detect posture with higher accuracy.

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For three types of induction-hardened shafts with different effective case depths, we measured the hardness distribution and observed the microstructure to quantitatively evaluate the effective case depths. The distribution of axial residual stress on the cross-section was measured by contour method. It was found from comparison between hardness and residual stress distributions that the maximum tensile residual stress occurs at a position equivalent to the hardness of the inner non-hardened material.

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In turning at high speed, a vehicle tends to deviate from a target path because the moment to car rotating becomes large. Taking lateral acceleration and transient moment into calculation is valuable to plan vehicle running speed within longitudinal, lateral, and angular acceleration, which can be generated by front and rear tires. Through analysis and verification with the test vehicle, it's shown that the proposed speed planning method that reflects generating rotating moment improves traceability onto trajectory.

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Pattern coating pistons are generally used to reduce friction loss in automobile engines. The friction reduction seems to be due to the change in oil film distribution depending on the coating pattern type. The oil film distribution is affected by the oil properties as well as the pattern type. However, there are many unclear points about the effects of oil properties on the oil film distribution. In this paper, the oil film distribution on the skirt was visualized using three types of oil. The calculated friction loss and oil film thickness were also investigated. As a result, the relationship between oil properties and oil film thickness and distribution was discussed.

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Hydrogen has excellent combustion characteristics such as high diffusion coefficient, wide limits of inflammability and fast burning velocity. The purpose of this study is to reduce cooling loss in a gas engine using hydrogen and hydrogen Mixer system (Mixer) engine was improved to hydrogen Port Injection (PI) system engine. As a result, the PI forming a heterogeneous mixture and making a localized hydrogen-rich in the combustion chamber, resulting in a shorter ignition delay. In addition, the PI has decreased cooling loss and increased brake thermal efficiency compared to the Mixer.

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In this study, abnormal combustion during high speed and high load operating conditions in a commercially available turbocharged SI engine was visualized using an endoscopic technique. Also, simultaneously measured in-cylinder pressure at different locations were thermodynamically analyzed. As a result, it is found that two abnormal combustion events occurred, and the second event was followed by the in-cylinder pressure oscillation with high intensity.

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Durability of a three-way-catalyst particles membrane filter was investigated experimentally. After manufacturing of the membrane filter similar to trapping of soot, a working-gas flow was changed from a wall flow type to a straight flow type to make a constant shear stress on the surface of the membrane. Then, by integrating the fitting curve of peeling rate obtained from the experimental points from zero to infinite time, the total peeling percentage was calculated.

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An injector with staggered nozzle hole arrangement is proposed to improve diesel combustion with suppression of interactions among fuel sprays. The injector has twelve spray holes, staggered on two injection angles of 79º and 55º from the central axis. The improvements in thermal efficiencies and the smoke reduction can be established with the staggered nozzle. The rate of heat release from the staggered nozzle has more active main combustion and smaller afterburning. The CFD simulations showed that the staggered nozzle can efficiently suppress the interactions among fuel sprays at the combustion chamber wall, resulting in reductions in the afterburning.

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Main reaction pathways of n-heptane and isooctane in low-temperature oxidation reactions have been considered to be the similar. In this study, n-heptane and isooctane were oxidized in low temperature oxidation condition using flow reactor and the products were analyzed using a comprehensive two-dimensional gas chromatograph equipped with a time-of-flight mass spectrometer. When n-heptane was used as fuel, reaction products containing two or three oxygen atoms were detected, suggesting that these products are the intermediates produced by low temperature oxidation reactions. In contrast, when isooctane was used as fuel, only several products has been detected. Notably, the several products originated from the oxidation of n-heptane and isooctane in flow reactor experiments are not existed in the detailed chemistry model of low temperature oxidation.

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For the purpose of reducing torsional vibration, we have developed a variable dynamic damper (VDD) whose stiffness is continuously variable so that the resonance point follows the rotation speed. The structure has been simplified by using rolling mechanism. We also conducted a transient dynamo test assuming an actual vehicle and clarified its performance. Furthermore, a theoretical analysis model was constructed and compared with the experimental results to clarify its validity.

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Using the road friction measurement method constructed in previous our studies, the measurement results of friction characteristics on dry and wet surfaces are shown. From this comparison, it is confirmed that the characteristics of the wet and dry roads studied so far can be expressed. Next, we study the velocity dependence of these properties. As a result, it is shown that the velocity dependence of μ-s characteristics on ordinary roads is almost non-existent. Finally, a method of expressing μ-s characteristics obtained by continuous friction measurement, which is a feature of this measurement system, is presented. And, it is shown the peak μ and lock μ obtained from these, and also shown the superiority of this measurement method.

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A detailed FEM model was used to simulate the relationship between the lateral force Fy generated on the contact patch of a rolling tire and the deflection of tire tread. On the other hand, we used a tire testing machine to measure in detail the force generated on the contact surface of the tire during rolling and observed the distribution of the force generated within the contact surface. As a result, the measurement results were obtained as predicted by the simulation. As a result, the validity of the concept of modeling the tread portion of TM Tire Model was directly confirmed for the first time through experiments.

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For further reduction of vehicular occupant fatalities, we must establish the vital body regions requiring protection for future safety technological developments. This study aimed to understand the main body regions affected in serious or fatal injuries of vehicle occupants during traffic accidents. We analyzed the detailed distribution of body regions using the Abbreviated Injury Scale (AIS) codes from the database of the National Automotive Sampling System-Crashworthiness Data System (2001–2015) in the USA. Based on the analysis results, the head (cerebral injury) and thorax (multifocal rib fracture and lung injury) are frequently injured in AIS 4 (severe injury) and AIS 5 (critical injury). In particular, elderly people are more likely to have thorax injuries in AIS 4 and 5 due to decreased bone mineral content. As the general population ages, we propose that future development of safety devices should be focused on both the prevention of body movement and reduction of the load on the thorax during activation of the inertia force in a vehicular cabin.

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Snow accretion on a radome makes millimeter-wave radar unusable big problem. We developed a structure in which a m-PPE foamed resin is placed as an insulator on the back of the ABS solid resin to obtain effective snow-melting ability to a radome with a heater element. The impact of reduced power consumption was computed employing heat transfer simulations. The millimeter-wave transmittance of the foamed resin was experimentally determined by measuring the dependence of the complex permittivity on the foaming factor. Thus, design factors for a radome with both high snow-melting efficiency and millimeter-wave transmittance are proposed.

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Aim of the present study is to obtain basic knowledge on lateral control in winter driving environment. We measured the displacement from the lane center position from the road frontal image recorded by on-board video camera. Also, influencing factors on the lateral deviation, such as road alignment, were analyzed. The results of the measurement revealed that the lateral deviation of the vehicle pass to the shoulder side is large in the winter driving environment. In particular, the lateral deviation to the shoulder side was greater in curved sections than in straight sections. It is supposed that the drivers’ fear of passing an oncoming vehicle may affect the lateral deviation of the travel track. It is desirable to be able to perform lateral control of traveling on snow trajectories where the paved road surface is exposed.

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A human predictive characteristic may affect the traffic accident factors such as prediction failure. In our latest research, we observed the area in front view where a human pays attention unconsciously while driving, using deep neural networks which reproduce human vision perception. In this paper, we analyzed the relation between the observed area and the eye movement of a person who is looking at front-view recordings. As a result, the hypothesis that large prediction errors attract stronger attention is validated by measuring the gaze of 14 participants.

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In this study, we conducted the experiment with recording driving behaviors using a driving simulator. In the experiment, the subjects would be impatient state caused by time constraints and they performed city driving including several driving situations in which their impatient state would change driving behaviors. As a result, using the driving behavior index such as driving operation and vehicle state, we have deepened our understanding of the driver's impatience driving behavior.

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Recently, a new Head-Up Display (HUD) which has a more inclined virtual image along the road surface than before has been proposed. In this study, we used a driving simulator to evaluate the conditions under which the shape of the vehicle information, such as speed, was acceptable or not; even when the vehicle information was deformed by the driver's head motion. As a result, the specification was defined as the parallax angle of the upper and lower ends of the vehicle information zone.

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The SQ-CCDC, a simplified questionnaire with a variety of driving-related variables, was developed using items that can represent differences among elderly drivers, and it is better to be able to provide feedback immediately after answering in order to operationalise it. It is not realistic to estimate the latent rank of respondents from their response patterns using LRT software. It is more practical to be able to estimate the latent rank from the sum score. In this report, we examined the cut-off points so that ranks can be analogously estimated from the sum scores of each subscale.

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The purpose of this paper is to propose a method to construct a surrogate model which can predict flow filed of velocity and temperature aiming at decrease the computational cost of CFD. In the proposed method, training data are corrected from CFD simulation based on a Design of Experiments (DOE). Then, after performing missing value interpolation on the training data, Tucker decomposition is applied to training data to extract features from the tensor type training data. For regression model, Gaussian process is introduced to construct surrogate models. The feasibility of the proposed method is illustrated by an application for CFD model using for the heat damage design problem.

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