The ignition delay times of n-C₇H₁₆/O₂/N₂ and i-C₈H₁₈/O₂/N₂ mixtures with different fuel, O₂, and N₂ concentrations were calculated using a detailed chemical kinetic model generated by KUCRS. Ignition delay times with high initial temperatures, where ignition process bypasses low-temperature oxidation, were analyzed. The dependence of ignition delay time on fuel concentration, O₂ concentration, heat capacity per unit fuel concentration, and third body concentration was distilled to establish a power law equation for ignition delay time using the scaling exponents for these parameters. For n-C₇H₁₆, the scaling exponents for fuel concentration, O₂ concentration, heat capacity, and third body concentration were 0.54, 0.29, – 0.38, and 0.08, respectively, and E/R was 14400 K. For i-C₈H₁₈, the scaling exponents for fuel concentration, O₂ concentration, heat capacity, and third body concentration were 0.40, 0.76, – 0.47, and 0.00, respectively, and E/R was 11900 K.

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We found that the deposit formed with oil/fuel mixture at the top of the cylinder liner and at the side face of the piston top land have lower ignition temperature than the deposit from cylinder head. We also found that the frequency of LSPI has strong correlation with the ignition temperature of the deposit which is varied by the additives in lubricant oil. We observed that the number of glowing particle as the ignition source is varied by air-fuel ratio. The LSPI frequency has been greatly decreased by the countermeasures for reduction of cylinder liner wetting and the enrichment control.

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The dynamics model and model-based controller (LQG servo controller) have been constructed to improve performance of diesel engine at transient condition. The input parameters of the dynamics model are injected fuel quantity, injection timing, external EGR ratio and boost pressure. In the model, one cycle is discretized into 7 representative points such as EVC, IVC, fuel injection, ignition, maximum pressure, EVO and IVO. The precision of the prediction of the model and the responsiveness of the controller were checked.

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The influence of diesel exhaust aftertreatment system on tailpipe emission of aldehydes during cold-starting of diesel engine was examined. Emission behavior of aldehydes at rear side of the aftertreatment system was compared with that of engine-out emission. Differences of the emission behavior indicate that dissolving of aldehydes in water and physical adsorption of aldehydes on wall surface had been taking place within the aftertreatment system during the early stage of after the engine start-up. Subsequently, the trapped aldehydes within the aftertreatment system were discharged from it as engine warm-up progressed. Emission trend of aldehydes roughly corresponds to that of exhaust odor intensity evaluated by sensory assessment.

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The effect of the compression speed on the auto-ignition of a single lubricant oil droplet was investigated by using a rapid compression and expansion machine. When the compression speed was the same as the automotive engine speed, the oil droplet with low temperature did not ignited. This result showed that the oil droplet does not initiate LSPI if it is compressed just after released from the cylinder liner. It was confirmed by using a single cylinder engine. LSPI did not occur when residual gas was totally swept out from the combustion chamber in order to excluding the contaminant which remains in the cylinder to the next cycle. This result indicated that the oil droplet with low temperature does not initiate LSPI.

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This paper describes that it applies to diesel truck engines with the tandem Pre-Turbocharger Catalysts (PTCs) set before the turbocharger. At first, it confirmed the advantages of the PTCs compared to a conventional Diesel Oxidation Catalyst (DOC) size and position. Then, it also confirmed that new emission reduction process hypothesized by tandem very small PTCs. Moreover, metal structure design substrate (LS-Design) is applied to the PTCs system. As a result, we have insight of the possibilities of multiple / tandem PTCs systems instead of the conventional DOC for truck applications with new-generation diesel engine and aftertreatment system.

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Mechanism of suddenly occurring behavior of low speed pre-ignition (LSPI) in boosted direct injection spark ignition engines was analyzed by using a single cylinder engine with an endoscope and a visualization engine with oil lubrication. Endoscope-visualized 1st cycle of LSPI showed droplet-like distributed luminous flame from spray-wetting exhaust side as the origin of flame propagation before spark ignition. For the validation of droplet flying mechanism, behavior and amount of flying droplet were visualized with the visualization engine. Droplet flying was observed only after enough fuel accumulation at piston crevice and time to start flying was found its dependence on the amount of liner wetting fuel. Finally, it was confirmed that subsequent abnormal cycles of LSPI occur only after enough operation time to accumulate fuel, by artificial LSPI input experiment with one cycle spark timing advance logic. These results indicated that accumulation of fuel and saturation of local oil dilution by fuel at piston crevice can be a contributing factor to the sudden occurrence of LSPI.

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LSPI is a big issue to enhance a load range of boosted gasoline engine. Although a lot of researchers have studied the cause of LSPI phenomena, a precise mechanism and procedure of LSPI are still not clarified. The authors have investigated the mechanism and procedure, utilizing an engine combustion experiment, numerical simulations and visualizing technique to understand the phenomena of LSPI.

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In order to realize a substantially eco-friendly tire which simultaneously offers appreciable drivability along with decent performance in necessity, authors have developed and proposed the large and narrow tire technology as one of the next generation tire technologies. For the expansion of the proposed tire, the authors have developed and evaluated a series of large and narrow tires in comparison with conventional original equipment tires for proposing them towards the next generation eco-friendly vehicles with various segment sizes. The first production of the proposed tire has been equipped by the premium electric vehicle which has been world-widely launched.

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Based on root locus comparisons between a 3 degree-of-freedom coupled model and approximate models (plane model, cross section model, simple roll model), effects of vehicle parameters on coupled dynamics, such as cornering stiffness using to determine the plane motion characteristics and roll stiffness using to determine the roll motion characteristics, were confirmed. Moreover, effects of vehicle parameter interactions on coupled dynamics were also explored. It is shown that the natural frequency ratio ω_n2/ω_n1 between a simple roll model and a plane model has a dominant influence on coupled characteristics. Additionally, effects of inclinations of principal inertia and roll axes on motion characteristics were also confirmed using the root locus analysis.

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This research deals with proposed draft for construction of a new personal mobility vehicle controlled using camber angle. We have discussed about vehicle stability and steady state characteristics. As a result, it was shown that this type of vehicle has very high potential from a viewpoint of vehicle behavior. We have proposed that the relation between roll angle and steering angle is set to functional relation. In such vehicles, however, it is found that yawing response of the vehicle has so much delay to the sideslip response. In order to solve the problem, we considered to improve the response using a control of steering angle or yawing-moment. From this analysis, it is shown that the vehicle characteristics can be improved using the control.

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In this paper, injury prediction algorithm for Advanced Automatic Collision Notification (AACN) based on Japanese traffic accident situation was developed. AACN algorithm was applied to Japanese large accident database by using a logistic regression modeling technique. Risk factors associated with driver’s risk of severe injury were Delta V, crash direction, seat belt use, multiple impact, occupant’s age, vehicle class(Passenger car, Kei car). Cut off value of severe injury risk of AACN algorithm was clarified by using ROC analysis. In addition, In-depth accident data base was applied to AACN algorithm to compare a relation between algorithm output and actual injury results.

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The influence of road surface conditions on traffic accidents is remarkable, especially in snowy countries. And accidents caused by polished ice on the surface of roads are still serious problem in winter. A remote sensing method for road surface conditions will be effective for the reduction of accidents. In this paper an NIR spectroscopic method was applied for the various roads whose surfaces were covered in ice. And the possibility to detect a road friction coefficient precisely by using around 1500 nm wavelength incident light at 60 degree reflection angle was obtained.

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The influence of road surface conditions on traffic accidents is remarkable, especially in snowy countries. And accidents caused by polished ice on the surface of roads are still serious problem in winter. A remote sensing method for road surface conditions will be effective for the reduction of accidents. NIR spectroscopic method was applied for the various surfaces covered in ice and the possibility to detect the friction coefficient was reported on the previous study. In this paper shows a theoretical verification for this method and the possibility for applying a snow surface.

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Digital Image Correlation method (DIC) was applied to evaluate a dynamic deformation behavior of car body structure under a side crash test. Relative displacement of cabin inner (Center pillar, Roof side rail, Roof cross member) was measured by onboard high speed stereo camera. Deformation behavior including spring-back from maximum deformation to final state was successfully observed by DIC. Displacement measured by DIC and draw-wire sensor as a reference were well corresponding. The difference of these data on 120 ms after collision was 2.0%. It’s concluded that DIC is useful for the detailed evaluation of dynamic deformation of car body in crash test.

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Some approaches to understanding “Interaction” of driver’s control maneuvers and the vehicle behavior based on the idea of the ecological psychology are studied in this paper. It pays attention into driver’s dynamic energy first and evaluation index of “Interaction” is derived. Evaluation index shows the possibility of decided the distribution ratio of correction FB of driver’s steering angle and the steering torque by the Simulation and the experiment. In addition, evaluation index shows effectiveness as detection of driver’s steering intention on the switch timing of the steering turning operation and returning operation by the vehicle test.

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Cars have used speech recognition and guidance for navigation systems from the early 2000s, however, the complicated mixture of multi-mode controls, such as a switch, touch panel, and speech, continues to be problematic. In this paper, we first discuss the problems with the conventional design of speech interface as equipped on a vehicle. Furthermore, to make clear the effect of equipping a spoken dialogue system, we experimentally compare the speech interface that includes natural language understanding (NLU) and spoken dialogue management (SDM) technology with the conventional speech command interface type of input. According to our evaluation, the total task time and the response time against LED stimuli showed significant differences between the two speech interface types. The NLU/SDM system showed a quicker response time for each task than did the command input system.

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The immersed boundary method (IB method), which combines an LES method with the law of wall (two-layer model) and local mesh refinement, was applied to the flow simulations around shapes of a vehicle. It was confirmed that the calculation results of the proposed approach showed good agreement with the experimental data and achieved short turn-around time owing to considerable reduction in time of the mesh generation process. Consequently, it was found the proposed approach is quite useful especially for the early stage of a vehicle development process.

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Heat storage system is expected as one of methods which are able to upgrade exhaust heat to valuable heat. Above all, CaO/H₂O chemical heat storage has greater potential because it generates not only hot heat but also cold heat. In this study, the authors aimed to realize a heat exchanger which operates at low temperature and low pressure and to demonstrate cold heat generation for air conditioning with CaO/H₂O chemical heat storage.

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We acquired NOx emission data, etc. by carrying out chassis dynamometer tests and road tests with using the sensor-based emission measurement system (SEMS) consisting of the NOx sensor, the digital tachograph and the gas flow meter. Based on these tests, we examined NOx emission evaluation method of a heavy-duty truck driving on road. Consequently, it was found that the indication of new proposal “NOx emission (g) per CO₂ 1 kg” has the advantage of canceling the measurement error of the instantaneous exhaust gas flow, furthermore the relationship between this new indication and the engine workload-based NOx emission (g/kWh) is strong correlative.

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On vehicles’ development, there are various calibration processes for each country and region, and the work load increases every year. Especially evaluation of exhaust gas emission is significantly important for the calibration processes. Nowadays, direct real-time mass emission measurement by using raw exhaust gas flow meter and exhaust gas analyzer without dilution has attracted attention. The usability of this measurement method was verified by comparing CVS method which is an official method of analysis, and a good correlation was observed at some transient test cycles. The result suggested that the measurement method has a potential of usability for real-time mass emission analysis relating to behavior of the engine for research and development.

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The accurate traffic light detection is an important role of automated vehicle driving. This paper focuses on a traffic light recognition algorithm by using computer vision and machine learning. In order to improve accuracy and reduce false detections, Region-Of-Interests generated from GPS and predefined map information is useful to identify target traffic signals. Therefore, we have used traffic signal database based on a precise point cloud map. We have evaluated the performance of typical detection methods such as AdaBoost, template matching and deep learning for driving images on public road. The results show the reasonable performance within practical computational time.

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