In the previous report, the effects of soot loading condition on soot oxidation rate in a Diesel Particulate Filter was investigated numeral analytically. This research reports to investigate the effect of engine operating condition at soot loading on PM structure and the soot oxidation rate experimentally and numeral analytically. As a result, PM structure change by engine operating condition and it is confirmed that PM structure and soot oxidation rate are related.

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In this study, using carbon particles as model soot, we evaluated the filtration performance of SiC fiber, which is potentially applied to gasoline particulate filter (GPF). SiC fiber is a material with high porosity and thermal stability. In experiments, we changed the filter thickness and porosity systematically. Hence, we could investigate the effect of filter thickness or porosity on the filtration efficiency and pressure drop. As the filter is thicker, the filtration efficiency increases on condition that the porosity is constant. On the other hand, as the porosity is lower by keeping the filter thickness constant, the filtration efficiency increases but the pressure drop also increases. The thin and wide filter is desirable to reduce the pressure drop on condition that the filter weight is constant.

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A control-oriented combustion control model with multiple fuel injections for a diesel engine has been developed by authors. In this paper, the model is installed as a feed-forward controller to a rapid prototyping system, its control performance is evaluated at the condition in which engine speed and torque demands are changing. The FF controller adjusts main fuel injection timing and fuel delivery ratio between main fuel injection and other injections, and controls incylinder pressure peak and its timing. The controller succeeded to control them and the availability of the model-based control system of the diesel combustion was clarified.

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Vehicle simulation for predicting fuel consumption needs to model a subsystem such as engine, transmission, tire, body and so on. However, it is not easy for non-automaker to develop a vehicle model without its design information. In this study, a method of subsystem modeling was developed for the vehicle fuel consumption simulation by the vehicle measurement using a chassis dynamometer. After that, the effect of tire rolling resistance coefficient performance on vehicle fuel consumption was evaluated quantitatively using this simulation model and a tire unit test rig.

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In order to reduce the fuel consumption of a light duty vehicle, sub-systems have been developed. In this study, to simulate the effects of such systems, a simulation code based on GT-SUITE was newly developed. Using this code, the fuel consumption at WLTC mode was predicted to see the future engine technologies, such as downsizing, variable compression ratio, cooled EGR, variable valve system and controlled cooling management system. As a result, by combining these systems, the fuel consumption may be reduced by 10%.

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Achieving cleaner air throughout the world requires reducing diesel emissions. Therefore, an after-treatment system called DPR-II has been developed in-house. It uses diesel fuel as a reducing agent (HC-SCR) to reduce NOx emission in diesel exhaust. The development of the fundamental technology could result in high NOx reduction performance at low to high temperature ranges. This study presents the exhaust reduction technology of the DPR-II system.

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NOx emission from a diesel passenger vehicle affects the atmospheric environment. It is difficult to estimate the NOx emission influenced by environmental conditions such as temperature and humidity, driving patterns, traffic conditions, and so on. In the authors’ previous study, a statistical prediction model of NOx emission was considered for efficient evaluation in the real world using real driving emissions and instantaneous vehicle data measured by portable emissions measurement system. In this study, additional considerations were made to improve the accuracy of model.

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The late combustion was visualized via high speed imaging of soot luminosity and UV chemiluminescence in a modern diesel engine. The mechanism of late combustion also was examined by 3-D RANS simulation. The phenomenon of late combustion in a diesel engine is the heat release occurs around the rich mixture at the spray tip, which is similar to the late combustion indicated by the single-shot diesel flame in a constant volume vessel. Engine experiments with an oxygenated fuel showed the fact that there was no significant effect of soot oxidation on the heat release of late combustion.

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We tried modeling of ammonia slip catalyst (ASC) for the purpose of model-based development of Urea-SCR system which is NOx purification device for diesel exhaust gas. In this report, we introduce the ammonia oxidation model on the PGM catalysts and the parameter identification method with genetic algorithm. The developed ammonia oxidation model can predict the influence of SV and PGM loading amount with high accuracy and is therefore expected to be useful as a kinetic model of PGM catalyst for the Dual layer (SCR+PGM)ASC.

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The new generation luxury hybrid coupe was developed and launched in 2017. During the development of the hybrid coupe, major improvements were made to the hybrid system by adopting the newly-developed multi stage hybrid system. In the new system, a multi stage shift device was installed between the previous hybrid system and the output shaft of the transmission to maximize the acceleration and environmental performance and to improve the drivability. This article introduces the characteristics of the new hybrid system and controls to solve one of the big issues that arose due to adopting the new hybrid system.

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Basically, there are two parts in car interior design, one of which is shape design. The first procedure of drawing 2D sketch, constructing 3D data and creating mockups is iterated until the final design is decided, which takes lots of time and cost. The subsequent part is surface texture design, where designers compare every texture sample to decide the texture to be used in the final design. It is hard to exchange the texture on the interested mockups to evaluate the whole impression. In order to solve these problems practically, this paper proposes a novel system “MOrse” with projection-based mixed reality technology, which enables visual deformation and texture manipulation simultaneously. Two subjective experiments verified the degree of perceived deformation for character lines and subtle continuous and discontinuous surface deformation and confirmed with and without ambient light on-the-fly change of the impression of the surface texture in several terms such as roughness and colorfulness. The result implies the usability of the proposed system as an interior design support system under certain conditions in which validation of discontinuous deformation is used with its validation around 10mm and roughness or colorfulness is manipulated.

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In this study, the acceleration sound of CVT vehicle is focused on the improving acceleration feeling. First, subjective evaluation is used for grasping the impression changes when rise time of engine speed and increasing engine speed per second changes. Second, the prediction model for acceleration feeling is constructed by multiple regression analysis. Finally, the model is considered by the experiment in consideration of driving motion and acceleration which uses driving simulator and practical vehicle.

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The test damper developed for a micro vibration suppression of a car body can produce a velocity-independence nearly constant damping force in a very small velocity range. Previous report elucidated the generation mechanism of damping force in quasi-static state. In this paper, firstly the attenuation model is enhanced to estimate damping characteristics of the test damper more precisely in dynamic state by introducing the time-delay elements into the previous model. Then the validity of modeling of damping mechanism is verified on the basis of comparison of simulations with experiments. Finally it is concluded clearly that the modified model can simulate the characteristics of damping force vs piston speed more precisely.

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This study focuses on the high-risk scene for pedestrian accidents wherein drivers pass a parked vehicle. In this experiment, using a test vehicle called JARI-ARV, the behavior 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 suddenly crossing pedestrian were examined in the traffic situations with an oncoming vehicle and with multiple parked vehicles. Based on our analyses, we clarified that the expert drivers pass the parked vehicles with better attention to multiple collision targets in the high-risk scene for pedestrian accidents.

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Driving at insufficient headway distance is the main factor of a rear-end collision. Therefore, in order to consider ways to prevent rear-end collision, it is necessary to survey the velocity and headway distance of vehicles driving on the road. In this research, we described an analysis method and an example of analysis results on the headway times, headway distances, velocities and vehicle types by a measuring system using light detection and ranging devices.

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This paper is a literature review on the methods of estimating field effectiveness for safety equipment such as automatic brake. We review and arrange these methods and their subjects systematically. Six methods on estimating field effectiveness are classified by the perspective of methodology and database type. That is five deductive methods using reference data, fault tree analysis, accident database, near-miss incident database and experiments. Furthermore, an inductive method using accident database. Each method has advantages and disadvantages. Common subjects are exposure estimated and selection of travel scenarios, which influence the accuracy of effectiveness. Therefore, it is important to interpret the results in the proper way after understanding these characteristics.

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We simulated a system which displays mild visual stimulus on head-up display, in conjunction with slow deceleration or lane change of preceding vehicles while automated driving on the expressway with a driving simulator. The visual stimuli were of an appropriate intensity to maintain driver's attention to the surroundings. When no visual stimuli were provided during automated driving, braking response times were longer than during manual driving. When visual stimuli were provided, the times were shorter than when no visual stimuli were provided. It will be possible to help keep the driver aware of the surroundings during automated driving by providing mild visual stimuli according to other vehicles’ behaviors.

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We made a prototype of the sensor-based portable emission measurement system (SEMS) consisting of a NOx sensor, a digital tachograph and a gas flow meter. This on-board device was connected to the tail pipe of a heavy-duty truck and traveled on the road, and the measurement performance of NOx and CO2 concentration was verified. Moreover, the operating condition of the EGR and the urea SCR system during road driving was estimated by using index of “NOx emission (g) per CO₂ 1 kg” which was calculated by the SEMS, the exhaust gas temperature and the engine cooling water temperature.

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There are few researches to respond to fluctuations in concentration of bio-methane fuel and load fluctuation of a generator using a co-generation gas engine generator of approximately 1kW. For this reason, in a relatively small scale local production type energy circulation system such as the GET system, it is necessary to develop a co-generation gas engine generator which can use the generated unpurified bio-methane gas to accommodate to the load fluctuation. The GET system is a bio-methane gas production paddy field of sustainable resource recycling type, and does not special auxiliary facilities. We have researched by using the bio-methane gas produced from the GET system as the fuel of a co-generation gas engine generator for usage of the electric energy and thermal energy supply to the air conditioning for the greenhouse. We have researched to apply the robust engine controller by combination of model matching and optimal observer (MM_OBSV controller) to the electronic governor of the co-generation gas engine generator. We indicate that a control system which is adapted to the input disturbance (load fluctuation and fuel concentration fluctuation) with the MM_OBSV controller embedded in the electronic governor of co-generation gas engine generator.

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Japan Petroleum Energy Center (JPEC) has been implementing the evaluation of the various reduction technologies to the evaporative emission from gasoline vehicles on refueling, parking, etc. In this study, we evaluated and analyzed the effect on the reduction technologies such as ORVR to the evaporative emission. We also experimented to study the effect of the refueling rate on the evaporative emission on refueling to ORVR.

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Diesel Particulate Filter (DPF) regeneration requires high exhaust gas temperature by post -injections, which causes issues of fuel penalty and emissions. Therefore, it is desirable to shorten the DPF regeneration period. Ag catalysts by conventional coating method can’t exhibit their capabilities expected, due to their poor contact between PM and catalysts. To improve PM-catalysts contact condition, a new coating method which enables to achieve “tight contact” between PM and catalysts was developed. Abnormal temperature rising characteristic accompanying improvement in PM combustion performance was able to coexist by adjusting coat length in DPF. This method enables to promote DPF regeneration, making improve fuel economy and emissions.

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In this study, the strain rate concentration factor is considered for high speed tensile test, which is now being recognized as a standard testing method for polymeric materials. For notched flat bar specimens, the strain rate at the notch root𝜀̇_notch cannot be determined experimentally and has to be studied analytically. In this study, therefore, the strain rate concentration factor defined as 𝐾_𝑡𝜀̇ = 𝜀̇_notch/𝜀̇_smooth is calculated by varying the notch geometry and specimen length. It is found that the strain concentration factor 𝐾_𝑡𝜀̇ can be estimeted from stress concentration factor 𝐾^∗_𝑡. The effects of specimen length and notch opening angle are also discussed to clarify the strain rate concentration factor.

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This paper presents a high-accuracy localization method for autonomous cars. In the method, we use inertial navigation system (INS) and a multilayer light detection and ranging. Three-dimensional normal distributions transform scan matching is employed and its estimation result is fused with the result from INS on the basis of a Kalman filtering algorithm. To determine uncertainty of the scan matching result, we utilize Hessian of the cost function. The localization method robustly estimates smooth and accurate vehicle trajectory. We conducted autonomous driving demonstrations with the method in public roads and these results are used to show the performance.

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