To analyze oil film behavior between piston and cylinder is a significant topic for reducing the friction loss. The oil film thickness is measured by LIF (Laser Induced Fluorescence) method in a visualization engine. Oil film pattern is visualized in test engine with pattern-coating pistons that have a difference in friction. It is clarified by the visualization that the oil film thickness is affected by the pattern coating.

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To analyze oil film behavior between piston and cylinder is a significant topic for reducing the friction loss in internal combustion engines. The oil film thickness is measured by LIF (Laser Induced Fluorescence) method in a visualization engine. Pattern-coating pistons with polka dots that had a difference in friction have been tested. As a result, the differences in oil film thickness by pattern coating that affects friction are observed.

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In order to regenerate the diesel particulate filters (DPF), temperature of the exhaust is raised by SFI (Secondary Fuel Injection). The purpose of this study is to predict spray feature injected by tailpipe injector in diesel engines. In this report, we calculated the spray in tailpipe considered multi-component of fuel simulated diesel fuel regarding numerical analysis. As a result, it is clarified calculation results can qualitatively reappeared real phenomena.

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In order to clarify the influence of fuels containing sulfur and ethanol on cylinder-bore wear, the wear measurements by utilizing a radioisotope technique were performed. The results showed that when fuels containing sulfur were used, bore wear rate increased at a specific water temperature and depended on the base number of the engine oil. For this reason, it is estimated that the corrosive wear is caused by sulfuric acid generated from sulfur in fuels.

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In the previous study, it had been found that bore wear increases with sulfur-containing fuels, which was assumed to be due to the corrosive wear caused by sulfuric acid generation. A hypothesis was also proposed that bore wear increases as increasing volume, acidity and reaction speed of the acid. In this study, the hypothesis was verified by investigating the influence of the bore-wall temperature on bore wear, and a wear measurement with in-cylinder injection of an acidic solution containing sulfuric acid. Furthermore, it was confirmed that those tendencies of corrosive wear does not depend on fuel injection types of engine.

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For improvement of thermal efficiency of diesel engines, it is effective to control the fuel injection timing and quantity by using the model-based control (MBC) on ECU (on-board) with cycle-by-cycle calculation. The authors previouslydeveloped an on-board in-cylinder wall temperature prediction model and wall heat transfer prediction model those area part of models for MBC. The present study measured the time evolution of local wall temperature and heat flux in thecombustion chamber to evaluate the models. As a result of the wall temperature prediction model, it was made clear thatthe maximum error was 1.3% at the liner. About the wall heat transfer prediction model, it was shown that the maximumerror of heat flux was 5.8% at liner except for the inner head, and the average error of heat flux was -5.8% at the innerhead except for the cavity side wall.

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The lean combustion of reformed gases has a potential for low NOx emissions and high thermal efficiency. The reformed gases are produced by piston compression of rich mixture in a reformer cylinder, introduced to a power cylinder with air, and ignited with diesel micro-pilot injection. The research is focused on the fuel reformation in the reformer cylinder. The reaction processes to the reformed gases and productions are first investigated by chemical kinetic simulations. Then, the engine experiments are conducted to validate the simulations, and the control of composition and productions of reformed gases by engine operations are discussed.

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The lean combustion of reformed gases has a potential for low NOx emissions and high thermal efficiency. The reformed gases are produced by piston compression of rich mixture in a reformer cylinder, introduced to a power cylinder with air, and ignited with diesel micro-pilot injection. The research is focused on the combustion characteristics of reformed gases in the power cylinder. The engine tests with representative reformed gases are conducted, and the operational ranges are investigated. Further, the optimum gas compositions for the various engine operations are analyzed from the points of ignitability and combustion duration with the kinetic reaction simulations.

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Due to their fuel economy, gasoline direct injection (GDI) vehicles are expanding their share of the market. However, different from traditional port fuel injection (PFI) gasoline vehicles, GDI engines emit considerably more particulate matter (PM). By considering that more stringent regulation is setting in the world for gasoline vehicles, a filter for gasoline soot will be needed even in Japan, which is called a gasoline particulate filter (GPF). In this study, using carbon particles as model soot, we have evaluated the filtration performance of SiC sponge potentially applied for GPF. Here, effects of the filter thickness, the pore size, and the porosity on the filtration efficiency were investigated, so that the condition for reducing the pressure drop with keeping the better filtration efficiency would be revealed.

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In the previous study, it was found that the late combustion at medium to high load operations is caused by a rich mixture that stagnated at the tip of the spray flame. However, the causal relationship between thermal efficiency and late combustion has not been well clarified. Therefore, in this study, the detail mechanism of late combustion reduction by the split injections and also the influence on thermal efficiency were investigated. As a result, it was revealed that late combustion was reduced by main split injections, as the rich mixture in both the inside and outside the cavity was suppressed.

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Theoretical and experimental evaluations have been carried out for the straight-line stability during high-speed in motorcycles for many years, and have been also applied to actual development. On the other hand, stability is lost when traveling at extremely low speed, and method of maintaining the stability has also been studied in recent years. In addition, research on two-wheeled vehicles realizing the standing stability control by mounting a large-sized gyroscope has been performed. Here, we report the result of improvement of stability at extremely low speed and standing stability control not by adopting mechanical gyroscope but by adding flexibility to the structure of the body.

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This paper proposes a semi-active suspension control based on Bi-linear optimal control with piston speed dependent damping coefficient limitation. It is difficult to maintain body motion control and smoothness, while typical sky-hook control and Bi-linear optimal control with constant damping coefficient limitation. However, the proposed bi-linear optimal control with piston speed dependent damping coefficient limitation not only achieves body motion control, but also improves smooth ride comfort. The effects of a proposed method has been proven by computer simulations and the control equipped vehicle’s test results.

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Regularization is known as a method that enhances the generalization capability to attain a high statistical accuracy with wide variety of data. Ridge regression, which is commonly used as the regression method with the regularization, is expected to be suitable for constructing sound quality evaluation models for the sounds emitted from industrial vehicles that produce various sounds, as the method does not reject explanatory variables. This study has revealed that Ridge regression has the higher capability to generalize the sound quality evaluation models on such industrial vehicles than Stepwise regression which rejects explanatory variables.

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Engine starting vibration level of hybrid vehicles has a variation in the same vehicle and there are various factors such as intake air, fuel, state of battery and backlash of gears. In analyzing the effect of these factors on the variation, it is necessary to solve two difficulties: multicollinearity caused by adopting conventional statistical analysis for large amounts of factors, and high measurement load for simultaneous acquisition of several types of time-series data. In this paper, we adopted machine learning for the factorial analysis and narrowed down the analysis target to control output of powertrain related to the exciting forces, which can be collected easily from ECU of engine and motors. Factors not found in the past investigation were found by random forest, which was a kind of machine learning and could clarify the contribution of the factors toward target variables. Load of learning huge amounts of the data was reduced by automation of analysis process. It was confirmed by simulation that the newly found factors were primary factors in the variation of engine starting vibration.

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Sense of self-agency (perceived control) has been proposed in psychology field, and it is the sense that “I am the initiator or source of the action”. In this study, psychological experiments using a simple driving simulator, adding auditory information as one of multimodalities assumed support of visual processing, were conducted and then elicited how operator’s sense of self-agency changes corresponding to a degree of consistency between time-series waveforms of operation and of auditory information. The result suggested that noise and signal could be redefined from the view point of the sense of self-agency toward noise and vibration of vehicle-body design.

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To increase development efficiency, the authors developed an engine noise and vibration development process that uses a hierarchical desktop engineering tool and knowledge base in the early phase of design. The aim of this process is to raise the maturity level of the initial model of large scale 3D simulation in advance and thereby reduce the time and effort involved in multi-objective optimization at later stages. This process can discuss four engine noise and vibration phenomena. Those phenomena are investigated using large scale 3D simulation at the detailed design phase. As a preliminary step to that phase, an initial design process was added in which specifications of main engine components are investigated using three types of simple desktop engineering tool (conceptual parts design review, 1D/2D simulation, and light 3D simulation). In addition, the database accumulated in past developments and benchmark tests makes it possible to judge whether the specifications of component provide the required noise and vibration performance even when there is no assembly model at the initial design phase.

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Previously the authors devised a new engine noise and vibration (NV) development process using the hierarchical desktop engineering tool and the knowledge base. In this research the authors applied the new process to an engine development and verified its effectiveness. From the initial design stage before creating the fully assembled 3D drawings, the specifications of main components were concurrently investigated using three types of simple desktop tool (conceptual parts design review, 1D/2D simulation, and light 3D simulation) and the database accumulated in past developments and benchmark tests. This enabled to avoid that main components significantly deteriorated the NV performance, and also to reduce the time and effort required for multi-objective optimization using the large scale 3D simulation at the latter stage compared with the past. These results demonstrated that the new engine NV development process is effective for increasing the efficiency of engine development.

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The present study aims to clarify how the information regarding winter road conditions ahead affects driver's risk avoidance behavior using static driving simulator. We precisely simulated the 11km expressway under winter road conditions. A total of 48 participants drove the expressway with ACC-ON condition after several training runs. Results indicated that the drivers took lower risk avoidance behavior when they were provided with information to encourage override in addition to winter road conditions.

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Reduced model of car deformation during frontal impact of NCAP was established from data base of one hundred of FE results. Predicted deformation of front side rail by the reduced model showed good correlation to FE sampled results, while the FE sampled results were clustered to four groups by referring buckling modes of front side rail. Relationships between accuracy of the reduced model and clustering of the database were discussed.

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As vehicle collision testing is both costly and time-consuming, various kinds of each vehicle component parts evaluation test are suggested. The boundary conditions were identified by means of simulation (FE Analysis). This method brings about a degree of side sill deformation equivalent to that which takes place in a vehicle collision test. Finally, the development of the vehicle component parts evaluation test for side sill was completed.

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This paper presents Wide Angle Fovea Disparity Map as a new concept of a disparity map. Wide Angle Fovea Vision Sensor achieves acquiring the input image with both wide field of view and high spatial resolution in in the central field of view simultaneously by a single sensor without increasing the number of image pixels. By applying this special-made vision sensor for the stereo vision system, the authors propose a method to generate the disparity map by which we can not only measure a distance of a vehicle very far away in front of the stereo vision system very accurately (this needs enough high spatial resolution) but also measure that of a bicycle located just aside the vision system by some reasonable accuracy (this needs also enough wide field of view). This unique disparity map has been inspired based on making an efficient use of the Wide Angle Fovea Vision Sensor. In this paper, the authors implemented the proposed method and experimented distance measurement of vehicle and bicycle in outdoor environment by using Wide Angle Fovea Disparity Map. In addition, we considered accuracy of its distance measurement from results, as paying attention to camera calibration problem we should improve for its practical realization in the near future.

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A field experiment was conducted in winter 2017-2018 using an automated vehicle equipped with adaptive cruise control (ACC), a vehicle for measuring lateral friction on the snowy and icy road surface using the Real-Time Traction Tool-Curve and a meteorological measurement vehicle, where various winter road conditions were recorded in Hokkaido, Japan. On an experimental route, we determined where the driver overrode the ACC and decelerated, an action we herein call a “driver interaction”. The study used an ACC-equipped vehicle to investigate how the road surface condition and the road configuration affect the likelihood of driver interaction in winter. The experimental route passed through two types of road: a nationally administered road, and a regionally administered road. Driver interactions were found to occur only rarely on the nationally administered road. Based on the results of this study, drivers are expected to be able to use an automated vehicle equipped with an ACC system in winter on roads whose geometric road design is on par with that of nationally administered roads, except under slippery road conditions on curves and slope sections.

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This study discusses the effects of stability control for tractor and three-trailer combinations on the lane-keeping performance. The stability control is applied to a tractor and three-trailer combination using active steering of the trailer wheels. The control effects are evaluated by examining computer simulation with the driver-vehicle system which consists of a vehicle model, a driver model and the stability controller. The stability control suppresses amplification of the lateral displacement of rearward trailers, whereas the lane-keeping performance of the vehicle without the stability control deteriorates. The lane-keeping-assistance system improves the lateral deviation of the tractor and the driver’s effort.

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Driver fatigue is contributed by various factors. One possible factor of driver fatigue is head movements and another is visual discomfort caused by visual blur. During whole-body vibration, vestibule-ocular reflex (VOR) function decreases visual blur. However, the VOR function may change based on the driver state. This study aims to clarify which factor has a relationship for subjective driver fatigue during long term driving, magnitude of head movements, changing characteristics of VOR functions, or consequent visual blur. A multiple regression analysis showed that visual blur had a greater relationship with driver fatigue than head movements had.

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At present, external-stimulation methods such as sounds or vibrations are popular; on the other hand, there has been little research on a method focusing on human psychological state. Therefore, we propose a method for maintaining arousal by inducing intrinsic motivations. This arousal maintenance was found to work well during manual driving, but there were stress accompanying the method of inducing intrinsic motivation during autonomous driving. Therefore, a method that does not become stress during autonomous driving was applied. This arousal maintenance was found to work well during autonomous driving.

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This study examines a driver assistance system to improve safety and fuel economy at a signalized intersection by indicating predicted signal aspects on road. The predicted signal aspects are calculated by the current vehicle velocity and the signal cycle. The driver assistance system informs the driver visually of the predicted signal aspects on the road by assuming a Head-Up Display (HUD). The driving simulator experiments are carried out to evaluate the driver assistance system. The assistance system encourages the earlier deceleration and prevents the emergency braking behavior or the risky passage through the intersection. In addition, the assistance system avoids the unnecessary deceleration and improves the fuel economy.

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This part describes the outline of equivalent temperature (teq), measurement of equivalent temperature in vehicle cabin and development of numerical thermal manikin. A measurement method of teq by a clothed thermal manikin was examined. Then teq measurement was conducted in a vehicle cabin. The teq, including the effects of air temperature, air velocity and radiation, was measured properly. In addition a numerical thermal manikin, including clothing model, was developed. The developed manikin model was used for the calculation of teq in Part2. The measurement results of teq were also used as validation data to confirm the accuracy of a simulation in part 2.

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This paper (Part 2) describes the outline of the proposed mesh-free simulation method and discusses the comparisons between equivalent temperature (teq) in the calculations and measurements under summer cooling and winter heating conditions based on the 3D-laser scanned clothing surface of the thermal manikin in a vehicle cabin by the mesh-free simulation. It is found calculation results of the teq and cabin thermal environment reproduce the measurements on the whole. The key factors for evaluating teq on each body segment of the clothed thermal manikin under cooling and heating conditions are also discussed.

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Loop heat pipes (LHPs) are two-phase heat-transfer devices using evaporation and condensation and are widely applied to various thermal control devices used in spacecraft, automobiles, PCs, LED, power semiconductor devices, etc. This paper reports development of the LHP using copper porous media for IGBT cooling on trains. The effects of wick shape, porous structure of the wick, and contact state between the evaporator case and wick on the evaporator heat-transfer coefficient are evaluated experimentally. This cooling system using the LHP and vehicle traveling wind can be applied to thermal management of transportation.

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In the actual driving on the road, it is important to maintain the emissions level of the time of type approval. In this report, we installed the PEMS in diesel vehicles, and measured emissions under various driving conditions. Next, we paid attention to the fact that the NOx emission can be regarded as a function of the engine speed and the engine torque. Furthermore, from measurement data, we devised and verified a method for grasping whether or not the NOx emission level at the type approval is maintained based on the Moving Averaging Window (MAW) method being studied in Europe.

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An autonomous driving system using GNSS and a high definition map can continue to drive autonomously even when the road condition are bad. However, under slippery road conditions such as on a snow-covered road, it is expected that the performance of tracking a target path deteriorates or in the worst case the vehicle could start spinning. Therefore, vehicle control to accurately follow the target path is important. In this study, integrated longitudinal and lateral vehicle control to follow the target path is formulated as a nonlinear model predictive control scheme using a nonlinear tire model and a single-track vehicle model. We prepared two types of tire models for asphalt and a snow-covered road, and simulated a double lane change on the snow-covered road. Furthermore, we implemented this controller in GNSS based autonomous driving system and its control performance is validated based on tests with an actual vehicle.

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Many organizations have tried to establish novel communication style among passengers using on-board electronic devices related with modern automotive systems that consists of various hardware and software. Although several robotic middle-wares have been proposed to manage and develop such systems, it is too difficult for artists to implement user experiences. To overcome the problem, we introduce a practical framework inspired by building blocks of Internet of Things, which consists of three elements based on IPv4 communication type related with the blocks. Applying an example implementation to several prototyping products on vehicles, suitability and feasibility of our framework are practically confirmed.

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This paper proposes a design methodology for SOA (Service-Oriented Architecture) of automotive software systems. The connectedness and autonomous-driving drive the fundamental change of the architecture of automotive systems from individual ECU-based to service-oriented. However, the quality requirements of the automotive software systems are diverse and stringent, including safety and real-time-ness. Therefore, conventional design methods to SOA for Web systems are not directly applicable. The authors propose QDDM4SOA (Quality-Driven Design Methodology) for SOA. In this article, the authors extend the QDDM4SOA to the service-bus of automotive SOA, a key platform component of automotive SOA, and demonstrate the effectiveness of the proposed method by experimenting the prototype systems.

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