The purpose of this study is to estimate the amount of splashing lubricating oil by secondary droplets from a single oil crown. Therefore, the secondary droplet diameter and the number of secondary droplets were estimated from the model formulation. Moreover, the mass fraction of lubricating oil contained in the secondary droplets was measured by the laserinduced fluorescence method. As a result, it was found that the amount of splashing lubricating oil increased with the increase of K-factor, which is a non-dimensional number using Weber and Laplace numbers.

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The purpose is to construct a model to predict the impingement behavior of diesel spray on lubricating oil film in postinjection. In this report, the impingement behavior of different liquids simulating spray droplets and lubricating oil is measured, and the critical K-factor is calculated to classify the droplet splashing and deposition behavior considering the difference of dynamic viscosity coefficient and the impingement angle of droplets. The critical K-factor was calculated from the experimental results as follows. K_cr=(We_d・La_d^0.2・(2θ/π)^-2.06)_cr=2100+6270δ_non^1.44・κ^1.10, We_d is Weber number, Lad is Laplace number, θ is impingement angle, κ is dynamic viscosity ratio.

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Introducing LNT catalyst into the market requires improvement of NOx storage amount and also catalyst poisoning countermeasures against sulfur contained in fuel. This study developed a high performance LNT catalyst along with two findings. First, since too much Ba causes the sintering of Pt particles, we found out that the LNT catalyst has a balance point of Ba amount corresponding to catalyst specifications. Secondly, an issue caused by the amount of sulfur remained on the LNT catalyst was improved by enhancing Pt density in the upper layer of the coating. As a result, high sulfur-purge performance was achieved.

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Homogeneous charge compression ignition (HCCI) combustion is promising a new combustion system reducing NOx and PM simultaneously without any penalty of fuel consumption. However, the operational range of the HCCI combustion system is limited because of some issues such as poor control of ignition timing and the excessive rate of pressure rise. In this study, a new combustion system based on the HCCI combustion process has been proposed. The combustion system has a divided combustion chamber of two parts, one is small and the other is large. On the combustion system, at first, ignition takes place in the small chamber, and then the burned gas ejected into the large chamber to ignite the mixture in the large chamber. In the combustion system, the combustion process in the large chamber is aimed to go on same manner of the HCCI combustion process. This paper presents the effects of compression ratio, supplying same fuel to the large chamber and the small chamber and EGR on engine performance, combustion characteristics and exhaust emissions.

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To remove ammonia slip during in-use commercial vehicles lifetime, there is an increasing need to accurately evaluate the aging of ammonia slip catalysts. In this study, modeling of the hydrothermal aging effect for platinum group metal catalyst was investigated. The model was developed by correlation between the hydrothermal treatment temperature, hydrothermal treatment time and ammonia oxidation reaction parameters. As for experiment and simulation results of developed model, the change of ammonia oxidation reactivity and selectivity by hydrothermal aging could be calculated accurately. In addition to this, reaction path analysis revealed selectivity at low temperature are more sensitive compared to one at high temperature.

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The lean NOx trap (LNT) catalyst model for the purpose of Model-based development of LNT, which is one of the NOx purification devices for diesel exhaust gas, have been developed. This report focuses on the systematic modelling method of the redox reaction during LNT regeneration. Since many reactions proceed simultaneously on LNT catalyst, it is necessary to observe each reaction independently for determining the reaction rate constants. Therefore, we first classified reactions on LNT catalyst into six categories according to the reaction atmosphere and the active components. For modelling of one of them, the redox reactions in LNT regeneration, we developed a ″build-up method″ that identifying rate constants of each reactions step by step using genetic algorithm. The LNT model, developed according to a 15-step systematic procedure, was able to simulate accurately the concentrations of H₂, CO, THC, NH₃, NO, NO₂, and N₂O at outlet of LNT catalyst. The developed reaction model showed the importance of water gas shift and steam reforming in LNT regeneration. Furthermore, the importance of NH₃ and N₂O as intermediates in the NOx reduction process was also suggested.

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The authors propose a novel concept of energy system which is named “virtual grid system” combining electric vehicles with a renewable energy such as the photovoltaic power generation. In this system, generated PV power is stored and transported by various types of electric vehicles. In this system, generated PV power is stored and transported by various types of electric vehicles. As the results of having studied to apply VG to Gifu University, the virtual grid system that is constructed with PV, commuter EVs and city buses can reduce more than 70% of CO₂ emissions of whole economically. Furthermore, CO₂ emissions can be reduced more than 25% compared with the system that PV power is supplied via conventional power grid.

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In order to overview the dynamic characteristics of vehicle, it is necessary to know the interrelationship of motion in each direction. For steering input, the three main movements are lateral, yaw, and roll. Among them, there are many studies on the relationship between lateral motion and yaw motion, as represented by rear wheel steering technology. In this paper, the relationship between roll motion and yaw motion are focused on, which has been rarely studied so far, and considered the characteristics of the relationship between the two motions. The structure of the transfer function of a linear 3-degrees-of-freedom model are theoretically analyzed, and verified by simulation calculations and experiments. As these results, the contribution of the design parameters that determine the response balance between roll and yaw are clarified.

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The dynamic characteristics of vehicle motion changes greatly depending on driving speeds. Now that autonomous technology and electrification technology is evolving, and the need for model-based development is increasing, it is important to design vehicle dynamics and its control strategies considering dynamic characteristics changes from extremely low speed to high speed. In this paper, the root loci of a threedegrees- of-freedom model considering tire lateral relaxation time were analyzed comparing with two simple two-degrees-of freedom models. In addition, the dynamic responses to steering inputs and road excitations were explored using simulations and actual vehicle experiments. According to the results, the structural principles of dynamic characteristics changes from extremely low speed to high speed were clarified.

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In a PMV that tilts inward on cornering, as with a motorcycle, the lateral force is mainly generated by the tire camber angle. Therefore, the steering angle required to drive on a trajectory is generally independent from the vehicle speed, as same as motorcycles. This PMV is steered by the steering wheel like a car, and there is a room to consider the matching between this steering interface and the steering characteristics. In this paper, the steering characteristics and the steering torque characteristics are compared with automobiles and motorcycles, and preliminarily consider the way to warn the cornering limit to drivers. In PMVs that do not show understeer characteristics or saturation of steering torque like cars and are not suitable for touchdown of the vehicle body like motorcycles, it seems necessary to warn the limit with additional torque to the steering wheel.

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Adaptive Driving Beam has parameters as design specifications, which are resolution of light-shielding, margin of light-shielding, luminous intensity, blur degree on boundary area of light-shielding and so on. In this study, we research effects of design parameters for Adaptive Driving Beam, especially for resolution of light-shielding and margin of light-shielding, to reduce pedestrian traffic accidents during nighttime using "A Survey Simulator to Evaluate Safety Systems (ASSESS)"

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With the social demand to reduce traffic accidents, understanding of driving behavior in traffic accident is important for not only developing automobiles but also for discussion on the standardization of ADAS(Advanced Driver-Assistance Systems). In this study, we conducted an experiment using driving simulator, and investigated the differences in driving behavior by age group (elderly, middle-aged, and young) when they were avoiding unexpected collisions. As a result, it was found that many drivers avoid collision by steering in high speed situation, and the avoidance direction is on the driver’s side. ESF (Emergency Steering Function) operation timing that less interfere with driver's steering maneuver has also been proposed.

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Aluminum is needed as power busbar for electric vehicle in place of Copper, which has price hike risk and weight problem. However, Aluminum surface generates insulative oxides easily, so that Aluminum power busbar needs surface plating. This reports Nickel coating development for Aluminum busbar that solved both cost and electrical performance issues. This technique would be applied for power battery of mass-produced electric vehicle.

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In the development of can-sealing, the aluminum welding is usually employed. However, it often causes trial and errors in the actual test. To prevent the errors, many simulation models were developed, but the accuracy was not enough. This paper presents the new methodology using model parameters. First, we identified the absorption ratio of fiber laser for solid and liquid aluminum by combining measured temperature with heat transfer simulation. Second, we optimized parameters for Fresnel absorption and recoil pressure model using response surface methodology. Finally, we demonstrated that the simulation result matches well with the actual test.

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In this paper, air entrainment into diesel spray was investigated. To visualization of the ambient air flow and measurement of entrainment characteristics, the Laser Induced Fluorescence-Particle Image Velocimetry (LIF-PIV) method was applied to the surrounding air of the spray upstream in a non-evaporative conditions. Also, we investigated the effects of injection pressure on the entrainment characteristics. The results show that the entrainment velocity increases and the tangential velocity decreases as the downstream of the spray. In addition, in the set-off region of the quasi-steady diesel spray, the entrainment velocity and entrainment mass flow rate increase with increasing injection pressure, although the ratio of entrainment mass flow rate to fuel injection rate changes slightly with injection pressure.

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The prediction of friction mean effective pressure (FMEP) is important when engine performance is estimated with model-based development (MBD) process. In this study, prediction of the FMEP of a single cylinder heavy duty diesel engine was attempted by utilizing a neural network technique. The experimental results, in which various operating and combustion parameters are included, taken by the engine under various operating conditions (5227 points) were evenly divided into training data (3684 points) and validation data (1543 points), and machine learning was performed by using training data. FMEP of the evaluation data were predicted by the pre-trained neural network model. As the result, it was confirmed that the predicted results of FMEP show good agreement with the actual results of FMEP of the evaluation data (experimental data).

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Using Pt-Pd fine-particles on a membrane filter made of alumina nano-sized particles, it was clarified that a cake layer of particulate matters deposited on the catalyzed membrane could be oxidized under the condition of temperature around 400 degrees Celsius. Nitrogen monoxide introduced is reacted with oxygen by the Pt-Pd catalyst to produce nitrogen dioxide which is diffused toward upstream side particulate matters layer. Depending on a wall flow superficial velocity, the diffusion of nitrogen dioxide is useful for low temperature oxidation of particulate matters.

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Highly efficient internal combustion engine is still important powertrain to meet a future carbon neutral society. The cooling loss gives a large impact to improve the thermal efficiency. This paper presents a study of the heat transfer mechanism in the SI engine for reduce the cooling loss. This article is highlighting the effect of wall temperature on local heat flux. To simplify the heat transfer phenomena, the experiment was carried out using rapid compression machine. The results indicate the heat flux increases with higher wall temperature caused by wall-flame interaction.

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A novel total hydrocarbon (THC) emission concentration estimation model is proposed for reducing engine development cost and simplifying measurement systems. In our previous report, we proposed a THC estimation model using the absorbance spectra of the Fourier transform infrared (FTIR) spectroscopy. In this report, the model is improved by employing a piecewise linear method to estimate lower THC concentrations in post-catalyst exhaust gas. The prediction error for THC concentration below 100 ppmC is less than 10 ppmC under both steady state and transient operating conditions. We also validate the model using a different engine and the same accuracy was obtained.

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In this paper, the fatigue strength of the roller chain is investigated by varying the press-fitting ratio between the bush and the inner plate. A single plate specimen with two bushes press-fitted into two holes at the plate ends is used in the fatigue test. The FEM analysis is performed to obtain the stress amplitude and the average stress on the fatigue endurance limit diagram. The results show that the fatigue strength can be improved under suitable press-fitting ratio δ/D <1.8×10-3 compared to the fatigue strength at the press-fitting ratio δ/D=0.

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In order to improve operability and traveling performance on off-road drive, off-road was categorized based on surface grain size and driver’s operations were analyzed. Drivings at Rock and Sand were chosen as a typical off-road driving in this study. Important characteristics in terms of driving force control design were identified by the analyses of wheel slip, rolling resistance, and drawbar pull. As the result, operability and traveling performance on sand drive were improved by proposed driving force control design.

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The purpose of this paper is to suppress clutch judder by machine learning, and the research was conducted on a two-speed transmission for EVs. The deep reinforcement learning model was developed for seamless gearshift control, and the gearshift results without control were compared with the gearshift results after training. As a result, a control rule that achieves seamless gear shifting while suppressing judder was automatically designed by applying deep reinforcement learning to gear shifting control. In addition, seamless gear shifting can be achieved for various patterns of friction coefficients, enabling the development of a robust controller for changing friction coefficients.

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The casting constraint for topology optimization with both-sided casting is discussed. Combining the relaxed one-sided casting constraint on a non-orthogonal grid and the automatic estimation of the separation plane by the power of gravity center, a method to realize both-sided casting without specifying the separation plane by the user is developed. Good one-sided casting performance was confirmed by using a cone-shaped exploration range for the downstream element. In addition, using the p-norm gravity center on the casting axis, the separation surface was set on the expected density ridge, and a good both-sided casting constraint was achieved. The directional dependence of the rigidity of the 3D cantilever beam and decelerator mount bracket are investigated by optimizing several casting directions. The peak stiffness increased in directions other than the orthogonal directions, such as straight front and side.

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We investigated the influence of connecting-rod I-beam-section specification on combustion-induced vibration by both experiment and simulation. Main findings are as follows: By shortening the length of connecting-rod I-beam section, the natural frequency of piston-connecting rod coupled vibration shifts from 2.5 kHz to 2.8-2.9 kHz. The biggest value of vibration transmission efficiency, which represents the transmission degree from the combustion impact to the vibration on the outer surface of the engine, is around the natural frequency of piston-connecting rod coupled vibration. The decay rate of vibration at the natural frequency of piston-connecting rod coupled vibration is bigger than the that of the other connecting rod on same frequency. These two results may come from the asperity contact of main bearing.

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This paper introduces a new active suspension system and discusses the application of the energy optimal control theory. In this new suspension system, an actuator and a damper are arranged in series. Thanks to this new design, the suspension system without an additional mass consists of an active mass-damper system. Applying the energy optimal control theory, it is shown by-the computer simulations that the riding comfort can be improved over wide range of frequency including the resonance frequency of the unsprung mass. The results show that the vibration of the sprung mass is reduced to a level which is lower than that of a Shinkansen car without causing an increase in the vibration of the unsprung mass. Additionally, the control law is interpreted and the mechanism behind the decrease in the vibration of the sprung mass is analyzed.

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This paper describes the development of modeling method to consider manufacturing conditions (injection machine settings, output parameters in injection simulation and so on) for polymer parts with analysis method for predicting a crack. It is well known that the material properties of polymers are influenced by molding conditions. Relationships between material properties and manufacturing conditions were quantitatively determined by various investigations on the test plate. The method for applying the effects by manufacturing conditions to material models and crash simulation model was proposed.

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It is well known that sufficient consideration must be taken for ammonia sampling because it has strong adsorptivity and high solubility in water. In this study, direct measurement and dilute measurement was compared as ammonia measurement methods to clarify the effect on the mass emission measurements. Furthermore, the influence of the sampling position at direct measurement was verified. As a result, it was suggested that the dilute measurement is more susceptible to the adsorption / dissolution loss of ammonia. It was also shown that sampling immediately after the tail pipe is the most advantageous for accurate measurement.

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The heavy-duty vehicle exhaust gas measurement system using the ZrO₂ type NOx sensor can be directly inserted into the exhaust pipe and is suitable for long-term road driving tests. However, this measurement system has a problem that the measurement accuracy of NOx concentration is inferior to that of the chemiluminescence analyzer, and NH₃ is erroneously detected as NOx. In this report, as a measure to improve the measurement accuracy, the calibration curve for calculating the NOx concentration is modified to match the exhaust gas of heavy-duty vehicles, and we examined the introduction of a NH₃ sensor to correct NH₃ interference.

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Evaluation and prediction methods of the outer panel sink mark by mastic adhesive hardening are few, and the generation mechanism is not sufficiently clarified. A tool for quantitative evaluation of the sink mark was developed, and the effects of panel thickness, amount of mastic adhesive, and distance between panel and reinforcing parts on the sink mark were investigated. In addition, a CAE prediction model was also developed to reproduce the experimental results.

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Thermal Interface Material (TIM) would be used to have efficient heat transfer in cooling system for Battery module of Electric Vehicle. Thermal Pad used to be applied in many electric devices with small size, so sticking process with few air is easy. Bigger size of thermal pad would be applied for Battery cooling system of Electric Vehicle, so air void is one of considering point for ensuring thermal resistance. This reports the measurement way with production size and massproduction process sample on the thermal resistance of thermal pad for Battery module of Electric Vehicle.

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In this study, based on the NHTSA-ODD classification, we define JASPAR-ODD, which can be utilized to define a basic architecture to be shared and referred in distributed development for ADS level3. The JASPAR-ODD consists of traffic participants, environmental conditions, physical infrastructure, zone, connectivity and operational constraints. The system model is built to define the ADS basic architecture by using SysML, and the hazardous scenario is analyzed to derive the safety requirements to minimize the unknown-hazardous region following the approach of Clauses 5-8 of ISO/DIS 21448. It is shown that another case than ISO/DIS 21448 can be extracted from this approach.

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In recent years, there has been an increasing demand for software updates using OTA and hardware upgrades using PnP, and there is a need for dynamic software control of network settings in automotive Ethernet. To address this need, the concept of SDN, which is used in the ICT field, is useful: SDN is a network system that separates the frame forwarding function from the network device control function, and centrally manages multiple SDN switches with an SDN controller. In order to realize this system, abundant computing resources are required. However, in an invehicle environment, these resources are limited. Therefore, in this paper, we propose an in-vehicle SDN that can be implemented with limited resources by limiting the role of the SDN controller. In addition, we implemented the proposed system on an in-vehicle microcontroller, evaluated the required resources, and confirmed that the system is feasible in an in-vehicle environment.

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