In this study, we proposed a numerical method to estimate the behavior of PM distribution in DPF both in PM-deposition and regeneration process. In the result, we found that PM oxidation was occasionally incomplete and partially remained in the DPF even if the PM deposition-regeneration process was repeated in the DPF. In such case, the phenomenon that the oxygen supply slightly decreased towards the rear part of the DPF was found, so that the remained PM in the DPF induced the new PM deposition. By using a novel model, PM deposition distribution and modeling of the oxidization reaction, where deposition-regeneration is especially repeated within DPF, could be performed and time-dependent behavior of pressure loss was considered. The present modeling will make possible suggest the required timing which performs compulsive reproduction control of DPF.

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This paper demonstrates the improvement of combustion and exhaust characteristics by adding hydrogen to city gas in a lean burn gas engine for power generation in half load. In the tests, excess air ratio is changed from 1.0 to 2.0 with various hydrogen additional ratios in half load. Furthermore, the combustion and exhaust characteristics are investigated by using heat balance and calculation formula for laminar burning velocity. As a result, it is revealed that hydrogen addition into city gas in lean burn is effectual not only for increasing brake thermal efficiency but also for reducing NOx and THC.

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Our diesel combustion calculation code using chemical calculation with a reduced elementary reaction model has brought enough accuracy for practical use on engine development. Aiming to obtain much more accuracy, a new idea was involved in a spray atomization model. This idea is that one of the parameters in the spray atomization model is varied by the velocity at injector valve sheet. The breakup just after the injection start is promoted by changing themodel constant. This new spray atomization model shows remarkable improvement on the heat release ratio estimation at the combustion calculation. Some calculation results are shown in this paper, and the validity of the idea is discussed here showing unstable in-injector flow calculated with a CFD code and observed with an experimental enlarged injector model.

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Based on the detailed analysis of properties of two types of SCR/DPF catalysts, which are used for aftertreatment systems for diesel automobiles, the hydrothermal aging factors have been investigated. Using the aging factors, the model for estimating the rate constant of the standard SCR reaction over hydrothermally aged SCR/DPF catalyst was constructed. It is confirmed that the rate constant of the standard SCR reaction is estimated using the determined aging factor regardless of the types of the catalysts.

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Reactivity of monolith Cu-exchanged chabazite (Cu-CHA) catalyst was analyzed to investigate the reaction mechanisms of ammonia selective catalytic reduction (NH₃-SCR). The reactions, namely Ammonia adsorption/desorption, NO reduction, NO₂ reduction, and NH₃ oxidation, were identified using monolithic H-CHA and Cu-CHA catalyst. A kinetic model for the steady-state NH₃-SCR over monolithic Cu-CHA has been developed based on the experimental results. The adsorption heat of NH₃ was measured by temperature programmed desorption (TPD). Arrhenius parameters for NO reduction and NH₃ oxidation were also collected using a surrogate gas bench apparatus. The model predicted the catalyst efficiencies well in various conditions.

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To understand decline of SCR activity by catalysts aging is important for expand of commercial vehicle lifetime. In this report, the deactivation of active sites caused by hydrothermal aging effect was modeled by NH₃ storage capacity decreasing with the rising of hydrothermal treatment temperature. Simulation results of developed hydrothermal aging SCR model showed good agreement with the experimental results of synthetic gas bench. Based on analysis of reaction path changing by developed aging model, activity at low temperature was decreasing and selectivity of NOx conversion at high temperature was changing for deactivation of active sites.

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The particulate matter (PM) discharged from the diesel engine is collected by a diesel particulate filter (DPF) and then removed. Deterioration of fuel consumption is a serious problem since exhaust gas temperature must be increased when PM removal is performed. In this study, the numerical computation for both the behavior of PM distribution in the DPF during PM deposition-regeneration process and the heat distribution in the DPF was performed. The temperature-distribution and its change in DPF as a function of the time during PM combustion were calculated by a newly developed model. It was concluded that the amount of increasing temperature change was far larger backside in direction than that near the entrance of an inflow way. The present model can be used for optimal designing of DPF with a catalyst by assuming several operation modes of DPF device before an experimental approach.

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Emission regulations of NOx have become stricter in recent years. Commercial vehicles are equipped with Urea-SCR system with high NOx purification performance. Simulation technology is utilized for efficient development of Urea-SCR system. The previously proposed SCR catalyst model had problem with prediction accuracy of NOx purification performance under high NO₂/NOx condition. In this report, SCR catalyst model was improved by considering of NH₄NO₃ and N₂O formation. As a result, simulation results of improved SCR catalyst model was good correlation with NOx purification performance and N₂O emissions of synthetic gas bench test results and engine bench test result.

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The deep learning model we developed estimates knocking sound pressure and in-cylinder pressure from engine radiation noise captured by a microphone. This model obtains the time frequency mask and transfer function from many engine radiation noise and in-cylinder pressure pair data. The input to the model is a time-frequency spectrogram of the engine radiation noise calculated by the short time Fourier transform. The time frequency mask extracts the knocking sound from a spectrogram. The transfer function is to convert the extracted knocking sound into an estimated in-cylinder pressure. We propose a knocking detection method that applies this model.

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Multi Stage Hybrid Transmission has employed four speed shift device with wide shift range to maximize both fuel economy and acceleration performance. It has top level quietness in luxury vehicle class, and hydraulic control system with high response and high accuracy to accomplish excellent shift performance. This paper describes these items in detail.

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Driving with trailer towing is useful for large capacity transport. Especially in the United States, trailer towing is common as a means of transportation. However, hitching to a trailer is very difficult task even for skilled drivers. This paper presents a steering control system which makes a driver hitched easier. To realize the system, we selected a four-wheel-steering as a steering system, and in-phase and out of phase steering control method based on the relative position of a trailer. We show the system effectiveness from experimental results.

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We propose a novel method to estimate operation characteristics of the following driver. If the lead vehicle suddenly decelerates to avoid collisions with interrupting vehicles, it may lead to an accident with the following vehicle since human drivers require a reaction time. This research assumes a driving scene when a human driver follows the autonomous vehicle. The proposed method estimates operation characteristics of the following driver and predicts the trajectory of the following vehicle. It is demonstrated that the proposed method shows great accuracy of the prediction compared to previous methods.

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To elucidate the mechanism of traumatic abdominal injury in vehicle occupants, a new modeling method for the small intestine, mesentery, and mesenteric vessels was developed by simulation based on the mechanism which the small intestine grew into a loop morphology. Injury of the small intestine, mesentery, and mesenteric blood vessels in abdominal impact predicted using the model was similar to the results of a cadaveric test. Therefore, this model has the potential to predict injury of the small intestine, mesentery, and mesenteric blood vessels. In the future, it is necessary to verify the model using many abdominal injury data.

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In this study, such kind of experimental tests were conducted by using the driving simulator. Normal drivers was following the forward vehicle while driving on the highway, and then Emergency Driving Stop System of the frontal vehicle started to operate. The frontal vehicle decelerated and finally stopped in the lane. The driving behavior of the driver who was driving the following vehicle was evaluated. From the experimental data, for this system, the method of information to the other vehicles and the method of vehicle deceleration were studied

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The deposition of snow on the radome surface, which significantly lowers the millimeter wave transmissivity, is a big problem for millimeter wave radar systems. The installation of a heater near the radome surface is an effective solution. However, electric conductivity of heater elements inevitably lowers the transmissivity. We tested various heater patterns and evaluated their effect on the transmissivity at 76.5 GHz. Heater patterns were fabricated on polycarbonate plates using a silver paste with a sheet resistivity of 0.2 Ω/square. We have succeeded in finding heater patterns having both sufficient heating and transmitting properties.

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Advanced Driver Assistance Systems (ADAS) are necessary for safe driving in complicated traffic environments. In some ADAS applications, it is necessary to recognize the free space area using multi sensors. In order to fuse and integrate the output of sensors, we need to handle the measurement conflicts between different sensors. Conventional methods such as Bayesian Filter increase the unknown or ambiguous information in the case of measurement conflicts between sensors. We propose an algorithm to decrease unknown information caused by sensors conflicts. We provide experimental results to compare the proposed method with conventional algorithms.

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Towards reduction of right-turn accidents at intersections involving pedestrians, we investigated the influence of traffic environments on rightturn driving behavior. Aiming to apply the driving behavior indices, which we proposed in our previous study, to right turns at intersections on public roads, we investigated the relationship between the indices and traffic environment using Naturalistic Driving Study (NDS) data. Analysis results of NDS data revealed that presence of stop signs and traffic signals, width of both intersections’ entrance and exit roads and crossing angle of the intersection are traffic environment elements that need to be considered when assessing collision risk with the driving behavior indices.

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This study describes the influence of positional relationship between real environment and virtual contents on driver's uncomfortable feeling when using 3D head-up display with adjustable image position. As the experimental environment, a straight and curve road was conducted in a test track. The radius of curvature was set to 60 meters. Participants were instructed to evaluate uncomfortable feeling for relationship between virtual contents and road environment which represented road alignment or route guidance on 3D-HUD in the environment. Based on the results, we discussed how the driver’s uncomfortable feeling was influenced by positional relationship between lane marking and virtual contents.

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Protection of vulnerable road users (VRUs) is a key focus. FMVSS111 required all vehicles to have a rearview camera installed in the US. New UN Regulation on visibility and detection of VRUs is developing in the Informal Working Group on Awareness of VRUs during Lowspeed Maneuvers. Many referenced studies investigated in nose-in situations although reverse parking is more common in Japan. This study evaluated the effectiveness of a rearview camera, a parking sensor and both a sensor and a camera system. The results indicated the three systems were effective in preventing collision with a moving child-size object when reverse parking.

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This study focuses on the high-risk scene for bicyclist accidents wherein vehcile drivers overtake a bicycle. In particular, this study focuses on the situations where a Bicycle potentially Sways. In this experiment, using a test vehicle called JARIARV, the behaviors of drivers with different driving skill, including expert, young-aged, middle-aged, and senior drivers, were examined. The driving indices of potential collision risk to a bicyclist suddenly change the travelling direction were examined in the traffic situations where a bicycle travels in front of the vehicle. Based on our analyses, we clarified that the expert drivers overtake a bicycle with better attention to both the risk magnitude and risk duration time in the highrisk scene for bicyclist accidents.

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Driving simulator experiments were performed to measure the driver’s trust state and driving behavior while using ACC. The results showed the followings: 1) the right foot position when using ACC differs for each driver, and 2) as the trust in the ACC increases, the possibility that operation intervention will be delayed when the system faces the unavailable situation increases.

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In a car under summer solar radiation, the surface and air temperatures become very high, for example the air temperature around driver’s seat was over 65 degree C. Thus, a ventilation system is one of the important methods for keeping comfortable thermal environment. In this study, in order to clarify the effect of temperature reduction in a car cabin by changing ventilation methods, the experiment of measuring temperature and the numerical simulation in a car cabin were conducted. In case of middle or high flow rate (100～150 m³/h), it was found that the effects of temperature reduction on the driver’s seat with FOOT mode ventilation and around the driver’s seat with FACE mode ventilation were remarkable.

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In order to increase the Kansei value of the glove box, we constructed a model to predict the opening behavior preferred from the relationship between impression evaluation and opening behavior characteristics. Based on this prediction model, we created a preferred opening behavior and verified its effect. From a result of the effect verification, we confirmed that the accuracy of the model structure and the preference were improved.

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In this paper, the stress distribution around the spot welds under the combined loads of shear, bending, peeling and torsion was separated into the components of each load by giving the displacement boundary conditions in the nominal structural stress calculation method for each load. Using this method, the contribution of each load to the nominal structural stress of the spot welded structure was calculated. The calculation results are useful for devising a simple fatigue test specimen that reproduces the fatigue phenomenon of the actual structural member.

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This study deals with the standing stability of two-wheeled vehicle at extremely low speed. Most of studies on vehicle behavior for two-wheeled vehicle are studying for characteristics beyond medium speed, and analyzes on low speed and stopped state characteristics have hardly been performed. Standing stability at extremely low speeds for two-wheeled vehicle is one of the major problems for ordinary riders. In this study, the equation of motion for two-wheeled vehicle at extremely low speed is constructed by two parts, one is the model for standing stability at zero speed, and the other is the geometrical model for vehicle trajectory. Using this equation of motion, it is shown that the effect of each design parameter on standing stability.

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