In the previous report, it makes an experimental study that effects of soot loading condition for pressure drop on DPF. This research report conduct an experiment of engine bench test that effects of soot loading condition for soot oxidation rate on DPF. As a result of soot loading condition have difference effect on soot oxidation rate. And it makes experimental consideration of influential factor (mean particle size of soot aggregation and space velocity of soot loading).

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In the previous report, the effects of soot loading condition on soot oxidation rate in a DPF was investigated experimentally. This research reports to construct the numerical oxidation model of a soot loaded. In the model, the effects of soot loading conditions including the mean soot particle diameter and space velocity on the contact area between the catalyst and cake layer are taken into account. As a result, the model developed can predict experimental results well.

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Lean combustion using sub-chamber was studied aiming at improvement in thermal efficiency of spark-ignition engines for automobiles which use compressed natural gas as fuel. By engine experiment, basic experiment by RCEM(Rapid Compression Expansion Machine), and numerical calculation, effect of improvement in heat efficiency by sub-chamber was clarified, and reason for combustion stabilization was investigated. The results show that gas jets from the sub-chamber promote flame propagation in lean fuel-air mixture, and sub-chamber-nozzle specifications and position of a spark plug are important factors for combustion improvement.

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Knock characteristics were investigated by means of engine experiments for hydrogen, ethane, propane and butane, and for methane-based binary fuel mixtures, in which one of these species is added as a secondary fuel. Knock of the methane-based fuel depends not only on the ignitability of the secondary fuel, but also on the specific heat ratio and burning velocity when the secondary fuel ratio is high. For this reason, hydrogen scarcely affects knock resistance of methane/hydrogen blends in the case of lower hydrogen ratios, whereas the knock resistance is sharply lowered for the higher hydrogen ratios.

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Impacts of hydrogen and carbon dioxide addition on knock resistance of methane-based fuels were investigated with a view to rationalize the improving effect of steam reforming of natural gas on methane number. Addition of hydrogen and carbon dioxide with a same volumetric amount to methane showed no impact on the knock resistance of fuels regardless of a volumetric proportion of methane. This is due to the fact that shortening effect of hydrogen on the ignition delay time and decreasing effect of carbon dioxide on specific heat ratio, which suppresses temperature increase in the unburned gas temperature, cancel out each other.

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Previous reports show that smaller-hole nozzle diameter and larger number of holes or highly compressed air can suppress soot emission in smaller-bore size engine adopted by the size similarity theory. In this report, other approach has been applied to achieve highly dispersed spray which was induced by the enlarged spray cone angle adopting redesigned nozzle-hole shape. The results show that ‘geometrical similarity of fuel spray’ can be obtained, which keeps soot emission at the same level while bore size is reduced.

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In the HCCI combustion, it is known that the influence of the combustion characteristics by the fuel property is large, and it is one of the issues to practical use. Therefore, to perform the three-dimensional combustion calculated using the reduced reaction scheme can correspond to a multi-component fuel authors constructed so far, and we studied the combustion control method corresponding to the ignition timing changes due to the fuel component. As a result of this study, the coolant temperature of cylinder head hasmore influence than that of liner. So, the possibility of combustion control was shown.

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The exhaust gas recirculation (EGR) is a widely used technology in internal combustion engines. However, its effect on combustion is the result of complex combination of many physical and chemical effects and it has not been fully broken down into the basic elements. In this study, the effects of EGR on the elemental combustion phenomena, laminar burning velocity and autoignition delay times, have been systematically investigated by numerical simulation using detailed kinetic mechanisms of combustion. Large effect was found for the laminar flame velocities while the effect of EGR on the ignition delay times was shown to be modest compared to the effect of the fuel in contrast to the small effect of fuel properties on the flame velocities. The effect of fuel reforming using exhaust gas was also discussed.

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Many previous experimental studies showed significantly decreased thermal efficiency in Dual Fuel combustion at low load compared conventional diesel combustion. In the present study, a combustion strategy is proposed based on engine tests to utilize high dispersed pilot diesel injection to promote flame propagation of premixed natural gas in a heavy-duty Dual Fuel natural gas engine. Then, the in-cylinder phenomena were investigated by using a 3D-CFD code. The results indicate that the combustion strategy proposed in the present study can achieve higher thermal efficiency than that of conventional diesel combustion at low load.

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An experimental study was carried out with a diesel/natural gas dual fuel engine to discuss the control method of intake gas using supercharging and exhaust gas recirculation (EGR). The base engine was a 4-cylinder 3L diesel engine and gas injectors were attached at the intake ports to supply natural gas. The performance and exhaust gas were measured and analyzed. The results show that hot-EGR is effective to reduce not only nitrogen oxides but also carbon monoxides and unburnt hydrocarbons for wide range of load, and appropriate supercharging should be applied at high load operation.

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Engine oil consumption should be reduced as it causes particulate matter, and an estimation calculation for engine oil consumption is required. The target of this study was clarifying oil behavior under an oil control ring, which assumed to affect oil supply volume for piston rings. Distribution of oil pressure in the circumferential direction under the oil control ring was measured. An increase in oil pressure was found in the piston down-strokes, and highest pressure was found at the center of the piston skirt. A negative pressure was found after the bottom top dead center, then pressure became as same as crankcase pressure because the negative pressure caused oil film rupture.

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In order to improve the fuel economy of the heavy duty trucks at a highway driving condition, the heavy duty hybrid truck with new type of hybrid electric assist engine system was proposed at the previous report. The new system consists of a downsizing diesel engine with a two-stage charging structure, which has an electric supercharger with bypass circuit and a conventional turbocharger, the hybrid electric motor and the small-capacity battery. The electric power consumption of an electric supercharger is equivalent to the amount of the regeneration power produced during high-speed driving where the opportunity of the regeneration is small. In this study, an electric supercharger for the heavy duty hybrid truck is produced experimentally. Next, the fuel economy of this heavy duty hybrid truck driving in an in-city mode and an intercity mode was investigated by using the “Hybrid Powertrain Test Bed System”.

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This paper presents an engine-in-the loop HEV simulation system constructed on CRUISE. In the presented system, the model of vehicle dynamics with driveline, motor and battery is driven by the actual engine torque which enable us to test real engine state and the performance of combustion engine operated at HEV mode under a given energy management strategy. The control issues of the system are introduced and a testing example is demonstrated.

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The extensive use of computer-aided design (CAE) is a standard approach in car crash simulation. As high-performance computation gets more available at a reasonable cost, it is becoming possible to produce huge amount of intermediate data such as the displacement of individual nodes. However, little is known about how to extract useful insights from the intermediate data. This paper proposes a data mining approach to CAE-based crash simulation. Using a dimensionality reduction technique, we demonstrate that the proposed method can automatically extract useful features from the data.

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Some tire cavity noise reduction devices have been commercialized in recent years. However, the use of these devices has been limited to only some high-end vehicle models because of cost constraints. This paper describes the proposal for a new device structure that achieves a 50% or greater reduction in weight and cost over previous devices as an approach to enable general use of Helmholtz resonators that can be fitted to road wheels. And this device has been successfully applied to mass-production models on the market.

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Micro-perforated panels with honeycomb core joined or contacted behind are molded by 3D printer, and their sound absorption coefficients are measured by an acoustic impedance tube. When the thickness of panel becomes as thin as 0.1mm, its bending natural frequencies concentrate and couple with Helmholtz resonance. Based on the interpretation of such thin MPP’s sound absorbing mechanism, a new type of MPP with cylinder around each hole is proposed so as to effectively control the natural frequency of panel bending and Helmholtz resonance separately. It is evaluated for such type of MPP to improve the performance of lower frequency range.

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In this study, we investigated an impression of engine automatically start sounds for charging electricity of hybrid electric vehicles having idling reduction function. Subjective evaluation test employing various idling sounds of hybrid vehicles were carried out. As a result, uneasiness feeling was found to be increased by the automatic engine start sound. In addition, appropriate range of engine rotational speed and loudness of the engine sound were investigated not to deteriorate the uneasiness feeling in cabin at the idling condition.

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This research attempts to analyze the factors affecting the stop or go decision at dilemma zone and to infer its driver intent. Distance to stop line, velocity and acceleration rate are selected as the factors for the decision making. Logistic Regression Analysis (LRA) is then employed to investigate how they contribute to the driver decision whether drivers stop or pass the intersection. The drivers’ intent is finally inferred through the LRA and the performance of the estimator was evaluated by Receiver Operation Characteristics (ROC) curve. Numerical analyses showed that the velocity influences the stop intent most among three factors, and the LRA was succeeded in inferring the drivers’ intent accurately at most one second after the amber onset.

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This paper describes results of occupant kinematics with different body sizes and reasons why these results occurred. FE model of Rollover Buck was built and human FE models(THUMS) were seated and positioned. The following two results were clearly observed. 1)lateral head displacement of AM95 case on the right side was largest in all the cases, and 2)direction of occupant kinematics was changed from inboard to outboard on the right side, which was not observed on the left side. Some discussions were made from the viewpoint of differences in restraint force, which originated from different body size.

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There are curtain shield air bag (CSA) and a side air bag as a main restriction device protecting an occupant at the time of a side collision. Therefore, this article studies CSA. CSA is a restriction device with two functions mainly. At first functions, CSA has a function to reduce the head injury of the occupant at the time of a primary collision. Therefore, it is desirable for CSA to be able to restrict the head by weak power for a long time. When the head is restricted in CSA, CSA is pushed on the head, therefore the volume of CSA decreases, the internal pressure of CSA increases and the head reaction force increase. Therefore, it is necessary to lower the CSA internal pressure during head restriction to avoid it. Therefore, the representative structure to lower internal pressure is a vent hall. At second functions, CSA has a function to reduce the possibility that an occupant is released outside a car. Therefore, it is necessary for CSA to maintain the internal pressure for a certain period of time. However, the second functions contradict the first. Therefore, in this article, CSA was based on structure without the vent hall. Achievement means to lower the reaction force at the time of the primary collision is to adopt structure to divert the gas of the chamber that the head is restricted to other chambers. With the main subject, two structures are considered. The first study is a method to gain the number of the duct. The second study of two pipe eyes is a method to increase the size of the duct. Therefore, it is the second study to have been effective. At last, it was inspected why it turned out such with the theory.

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This paper proposes a velocity control method in order to achieve automated driving in city area. Firstly, this paper introduces “safe velocity,” the upper limit of velocity for ensuring collision avoidance toward pedestrians’ any direction changes. Next, a direction prediction model is constructed to obtain the future positions of pedestrians in accordance with other obstacles. Thirdly, a velocity control method based on the prediction is proposed. This method adopts Final-State Control algorithm to minimize square sum of jerk (differential of acceleration) for improvement of comfortableness. Simulations and driving tests are conducted to confirm the effectiveness of the proposed method.

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The aim of this stydy was to investigate driver behavior when resuming control from a lower level of automated driving system. Fourteen drivers participated in a driving simulator experiment to investigate the aim. The driver’s vehicle could automatically adjust a headway distance to a lead vehicle and keep its lateral position in a lane. After automated driving for about twenty-five minutes, the lead vehicle unexpectedly slowed down and the driver’s vehicle could not adjust the headway distance automatically. Drivers had to step on the brake pedal to avoid collision with the lead vehicle. Both visual display and auditory tone were given to drivers to signal limited automated driving. The results of the driving simulator experiment showed that many drivers were unable to react to the limited automated driving appropriately, and the risk of the collision with the lead vehicle increased because it was difficult for drivers to notice both visual and auditory displays. the findings suggest that it is important to design both visual and auditory displays so that drivers could notice the limited automated driving.

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This paper describes the results of driver reaction time and annoyance when various type of visual target is presented on head-up display. In the experiment, a tracking task with steering wheel and accelerator pedal was conducted to measure reaction time to various type (size, color, etc) of visual target and to evaluate annoyance when such target was presented. Young and elderly drivers were instructed to perform the tracking task under situation that the target was presented in random interval. Based on the results, the influence of the type of visual target on reaction time and annoyance was analyzed and discussed.

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Fuel consumption and emission performance comparison between Worldwide harmonized Light vehicles Test Procedure (WLTP) and JC08 test cycle were investigated by chassis-dynamometer tests using 12 test vehicles in which newer technologies were installed. In most of the vehicles, fuel consumption in WLTP was almost as equal as that in JC08, though CO and NMHC emissions increased in WLTP because of a couple of reasons such as cold start control, high rate of acceleration and inertia weight setting.

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Zinc coated steel sheet that doesn't need de-scaling treatment in hot-stamping process was developed. We investigated its formability and weldability. The developed steel sheet had less friction resistance and better unti-galling properties than that of uncoated steel sheet because the oxide scale doesn't occur. As a result, the developed steel sheet exhibited better hat-channel drawability in hot stamping. Also, the mechanical properties of spot welded joint of hotstamped developed steel sheet are similar to that of de-scaled uncoated hot-stamped steel sheet. Moreover, the developed steel sheet had good consecutive spot weldability and low delayed failure sensitivity of spot welds.

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This paper investigates the real-time optimal feedback control of a micro ground vehicle (MGV) in the Kturn caused by a nonholonomic system characteristic. The modified Carathéodory-π (MC-π) solutions, which implemented the tracking controller into the Carathéodory-π (C-π) solutions, is used to drive the MGV in realtime. The optimal control problem is prescribed as a minimum-time maneuver of the MGV to traverse from an initial start point and reach its goal, and it is solved using pseudospectral (PS) optimal control theory during each interval of the sampling time of MC-π solutions. Experimental results demonstrate the advantages of the MC-π solutions over the real-time optimal feedback K-turn maneuver.

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An approach to identification of dynamical model with real-time experiment design is proposed in this paper. The approach consists of parameter identification loop and receding horizon optimization loop for real-time design of experiment (DoE). D-optimality is chosen as cost function for the DoE and C/GMRES algorithm is exploited to solve the receding horizon D-optimization problem, which enables us to combine the DoE algorithm with the parameter identification loop. Finally, application result in identification of transient model of a combustion engine is demonstrated.

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Both ride comfort and following performance are important for passengers who are in a car. However, there is a trade-off between the two in automatic steering control of automobiles because ride comfort requires slow response and following performance requires quick response. In this paper, a new automatic steering control method is proposed to improve the trade-off by applying nonlinear weight functions to the lateral position error and the yaw angle error of automatic steering control. Consequently, the efficiency of the proposed method is confirmed by simulations and actual vehicle experiments.

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