Natural wind influence on fuel consumption (WIF),β_f for a highway heavy truck (80km/h(22.2m/s)) is studied of which the aerodynamic drag to yaw angles is approximated for a flat body. The quartered mean wind directions in the real wind model which was previously proposed for passenger cars (100km/h(27.8m/s)) to understand the short-term WIF by us is here similarly applied to a heavy truck to obtain the short-term averaged WIF,β_fi for mean head wind(i=1 ,|Θ|<45°C), mean side wind(i=2 and 4, 45°C<|Θ|<135°C) and mean tail wind(i=3, |Θ|>135°C) where Θ denotes wind direction. The short-term WIF for a truck at headwinds is shown to be large while the long-term WIF estimated with the extended application of SAE J1252(1981) is small.

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Recent years, the regulation of emission and fuel consumption have been becoming stricter. On the other hand, additional devices of engine make the cold-start emission calibration more complicated. For these reasons it is difficult to optimize cold-start emission. In this paper, the new methodology of cold start emission calibration is proposed, and it is shown that cold-start emission behavior is simulated by dynamic modeling methodology and optimal engine operating condition from the start to the end of FTP 1st. hill is obtained by optimization using dynamic model.

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An instantaneous fuel flow and an in-cylinder pressure of every cylinder and cycle were measured in actual vehicle. The indicated work and the indicated specific fuel consumption during driving cycle were calculated, and fuel economy diagnosis system was developed by using those results.Using this system,fuel economy improvement of CVT vehicle compared with 4AT and 5MT vehicle was quantitatively analyzed.

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New combustion and fuel technologies were applied to a multi-cylinder diesel engine to improve both emission and fuel consumption. Performance of the multi-cylinder engine with 3-stage turbo charging system was investigated with JIS#2 diesel and an optimum fuel derived from a previous study to determine engine control parameters for each fuel. Steady-state operations for representative engine speed/load conditions were conducted to clarify the relationship between engine performance and engine control parameters. Also transient-state operations (JE05 mode) were conducted to achieve simultaneous reduction in emission and fuel consumption. The results shows that both emission (NOx < 0.2 g/kWh, PM < 0.01 g/kWh) and fuel consumption (10 % improvement) targeted in this study could be achieved with the optimum fuel as well as JIS#2 diesel. And especially it's clarified that the optimum fuel can simultaneously reduce NOx and PM in contrast to the conventional diesel fuel.

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Global emission legislation becomes more stringent and requires drastic reduction of NOx emission. Future legislation has a focus on real-world, in-use emissions. Calibrating urea SCR systems has become complex and time consuming. A model-based approach is presented which cuts development time and costs. A phenomenological SCR model fitted on engine dyno experiments is used for off-line simulation and on-line urea dosing control. A control strategy which incorporates the real-time model for NH₃ storage control is demonstrated to accomplish good NOx conversion and low NH₃ slip. The addition of a feedback sensor allows correction for system deviations in a closed-loop manner.

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According to the worldwide enhancement of emission regulation, auto manufacture adopts Urea SCR system on bigger diesel engines and is required to develop its OBD monitoring method.
This paper investigates the accuracy improvement of NOx conversion ratio determination as SCR catalyst deterioration detection parameter by analysing the internal NOx conversion mechanism of the catalyst.

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Datsko-Yang method is that, it is able to easily judge about fracture limits in bending of flat shape plate made of extruded aluminum. However, in extruded aluminum square tube, fracture in bending is often occurred at corner of edge. So, this paper describes the fracture judgment formula that improve of Datsko-Yang method. That formula fits not only flat plate but also corner of edge.

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The purpose of this study is to improve the prediction accuracy of bending fracture in impact CAE analysis of aluminum beams. In previous report, the fracture judgment formula was derived from improvement of Datsko-Yang formula that can judge the bending fracture limit. By applying this judgment formula to the FEM simulation, bending fracture of the corner part was predictable in CAE. In addition, the prediction accuracy of bending fracture was verified in static and dynamic test.

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To investigate the events that could arise when fighting fires in vehicles with compressed hydrogen CFRP (carbon fiber reinforced plastic) composite cylinders, we conducted experiments to examine whether a hydrogen jet flame caused by the activation of the pressure relief device (PRD) can extinguished and how spraying water influences the cylinder and PRD. The experiments clarified that the hydrogen jet flame cannot be extinguished easily with water or dry powder extinguishers and that spraying water during activation of the PRD may result in closure of the PRD, but is useful for maintaining the strength of CFRP composite cylinders for vehicles.

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In vehicle dynamics analysis on the on-center, vehicle transient response characteristics to steering wheel torque have attracted attention. In this study, factors to decide the characteristic of yawing motion to steering torque was analyzed by using a driving simulator that presents subjects only image information. As a result, it was found that it is important that perceptual thresholds of both steering wheel torque recognition and yawing motion recognition are almost matched, and relationship between the sensation of steering wheel torque and the sensation of the vehicle dynamics which is received from angular velocity of driver's gaze angle change is linear.

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The trade-off between fidelity and computational performance must be considered when selectinga suitable vehicle model for numerical analysis studies.This paper explores the effects of model fidelity in the minimum-time cornering of a vehicle. An optimal control problem is constructed to evaluate both a point-mass model and a rigid-body model including a time-axis folding method to configure a U-shaped course layout. Employing a direct, pseudospectral method results in optimal trajectories that are similar for both models, if characteristics of the tire friction force are the same. However, it is possible to obtain time history characteristics of each tire's friction force by rigidbody model analysis. By comparing experimental data of a radio controlled vehicle with numerical results, the proposed computation approach yields adequate results.

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In this study, we focus on rear-end collision accident when following a preceding car. We performed experiments with a test driver in order to analyze drivers' brake initiation timing in normal safety driving. We concluded that drivers' braking timing can be characterized well in phase plane of the Gap(D) between two cars and the proposed index (K_{dB_C}) that is modified version of the index (K_dB) by adding the preceding vehicle's velocity.

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led tests were conducted using a pregnant dummy to study injury risks pregnant occupants have potential to receive in frontal impact accidents. Based on tolerance value generated by leading-edge technology, dummy kinematics, injury value etc. measured under with and without seat belt condition and seat belt misuse condition were compared. Then, effect of protect performance gained by wearing seatbelt properly was confirmed.

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While a human finite element (FE) model for crash simulations incorporating failure models is capable of predicting occurrence or nonoccurrence of bone fractures, it is difficult to quantitatively estimate probability of fractures using the results of the FE simulations. Simple injury indices that can be used for estimating probability of fractures using human FE models without failure functions are needed for avoiding check of element stress or strain at unpredictable fracture locations. The goal of this study was to develop a pelvis injury index that can be used for quantitatively estimating probability of pedestrian pubic rami fractures.

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In this study, sled tests were carried out using Hybrid III 3YO and Q3 dummies seated in impact shield CRSs and 5-point harness CRSs under the impact conditions specified in ECE R44. The Hybrid III 3YO and Q3 kinematic behavior and injury measures were compared for these various types of CRSs. The global dummy kinematic behavior was comparable between the Hybrid III 3YO and Q3 dummies and was different between 5-point harness CRSs and impact shield CRSs. In the impact shield CRSs, the chest deflection was large and depended on the shield structure.

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Toward the commercial production of gasoline HCCI engines, it is important to understand the effect of fuel characteristics on HCCI and SI combustion. The model fuels used in this study have the same octane number but consist of different components. Using these model fuels, the effect of fuel components against two Auto-Ignition phenomena, which are 1) HCCI combustion and 2) knocking in SI combustion, was analyzed with experimental approaches. As a result of the analysis, an experimental equation was proposed for the HCCI timing of the multi component fuels, and it showed good agreements against gasoline fueled HCCI timing.

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In this study, a Homogeneous Charge Compression Ignition (HCCI) engine was operated on blended test fuels of dimethyl ether (DME) and methane, which have different ignition characteristics. The simultaneous measurement of light emission and absorption of HCCI combustion were used to examine the combustion characteristics of the HCCI combustion. This is to investigate the effects of the mixing ratios and quantities of two types of fuel on the combustion characteristics. Also, we analyzed cool flame reaction behavior in detail on the basis of in-cylinder spectroscopic measurements. As a result, it was found that the light emission intensity at wavelength corresponding to HCHO had the peak for the period when the absorbance at wavelength corresponding to HCHO increased rapidly. The behavior of the light absorption (timing, absorbance) depends on the quantities of DME. Additionally, the behavior of the absorbance at wavelength corresponding to HCHO and calculated result of HCHO mole fraction were qualitatively corresponding.

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The influence of the engine oil property and the cam follower surface coating on the friction characteristics was examined with a cam follower friction test apparatus. It was found that the friction changes with the contact load, the camshaft rotation speed and the lubricant temperature such as the contact condition is governed under the mixed lubrication regime. It also changes markedly with both the property of low SAPS engine oil to protect the exhaust gas after-treatment device for diesel engines and the surface coating condition of the follower surface. The followings were made obvious. (1) The friction changes under the running-in with the frequency of test. (2) The friction is influenced by the combination of the follower surface treatment and the low-SAPS engine oil. (3) The effect of it on the reduction of friction becomes the largest when the DLC coating and the DH-2 class oil are combined.

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The wear of nozzle valve seat of the diesel fuel injector affects the fuel spray behavior. In this study the influence of fuel injection condition and fuel property upon the wear was investigated with a newly developed wear testing machine which is constructed based on a commercially used common-rail injection system. The temperature at nozzle valve seat and the fuel lubricity were changed as the parameter, and the result indicated that the higher temperature gives larger wear volume. Observation of worn surface by FE-SEM and surface elemental analysis by means of EPMA are also conducted.

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The premixed charge compression ignition combustion (PCCI) can reduce NOx and Smoke simultaneously. In this study, the start of combustion was delayed to decrease the maximum pressure rise rate (dP/dθ)_max of PCCI in a single cylinder diesel engine which is installed digital hydraulic variable valve actuation. The result of exhaust emissions and (dP/dθ)_max of PCCI was compared with the result of diesel combustion. Also PCCI was applied at light load from low to high engine speed. At an engine speed of 1000rpm, PCCI can decrease much more NOx than the conventional diesel combustion at the loads of between 0.1 and 0.6 MPa. And also PCCI is able to decrease lower (dP/dθ)_max to the same level as the diesel combustion at the loads of between 0.1 and 0.4 MPa

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In this study, cold startability of E85 was researched with a focus on the vaporization characteristics. Cold startability was tested with E85 of which Reid Vapor Pressure (RVP) is equivalent to gasoline. The engine failed to start when the E85 was used. The vaporization simulation was conducted on the fuels. As a result, it was revealed that E85 vaporization is lower than gasoline even if RVP are the same. To enhance the fuel vaporization, increase of injection quantity and usage of a high RVP fuel were effective. To keep the same engine startability as the gasoline, need about 3 to 6 times fuel injection or 30-50kPa higher RVP would be needed.

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A direct cylinder injection system is expected as a fueling system in hydrogen fueled S.I. engines since it has a potentiality to mitigate decrease in output power which is disadvantageous nature of gas fuel engines. Technology to reduce fairly high NOx emissions level that is characteristics of direct injection SI hydrogen engines, however, is still underway of development In this study new concept of optimizing combination of injection, ignition and combustion based on an application of high pressure injection up to 20 MPa, which enables notable reduction in NOx emissions without any tradeoffs on decrease in output power and thermal efficiency is introduced in direct injection S.I. engines.

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The reaction paths were analyzed in order to clarify the relationship between the fuel molecular structure and its ignition characteristics. The differences of molecular structure appear in RO₂ Chemistry and Fuel Fragment Chemistry. Almost all hydrocarbons are converted into ketohydroperoxides and fuel fragments, such as aldehyde, ketone, alkene and smaller alkyl radical, during Low Temperature Oxidation (LTO) range. The contents of fuel fragments are mainly controlled by the length of straight chains in the molecule. LTO start is dominated by both fuel size and smaller ketohydroperoxides reactions. And then, LTO ends when the reaction rate of CH₂O + OH is faster than Fuel + OH. Finally, H₂O₂ concentration and temperature at the end of LTO determine the timing of ignition.

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We have performed the chemical kinetic analysis on the oxidation of binary mixtures of n-heptane with methane, ethane, propane, n-butane and iso-butane. Effects of different ignitability fuel addition on the kinetic mechanism are summarized in the following; (1) decrease of the net reaction rate due to the change of fuel concentration, (2) OH radical consumption and regeneration by main and sub fuels, (3) aldehyde production, and (4) change of the fuel oxidation mechanism due to radical environment in the low temperature oxidation (LTO) range. H₂O₂ concentration and temperature at the end of LTO determine the ignition timing.

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Compressed hydrogen gas is currently the most popular choice for a fuel storage mode for vehicles. For the practical design of suitable vessels and hydrogen filling stations, it is necessary to be able to accurately predict the temperatures of the vessel wall and gas during charging. Recently, Monde et al ⁽¹⁾ . proposed a thermodynamic model for the gas in the vessel during charging. In this paper, on the basis of the Monde et al. model, the temperature of the precooled hydrogen and the filling time are analyzed for a practical vessel and hydrogen charged range. Equations predicting them are derived using the calculated values.

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Numerical analysis has been performed for turbulent flow with heat transfer in a square duct with 45 degree ribs by using an algebraic Reynolds stress and turbulent heat flux models. Calculated results are compared with the experiment in order to confirm the validity of the presented model. It has been found that the calculation can reproduce reasonably the measured velocity profiles including secondary flow vectors. Besides, two kinds of turbulent models are applied to temperature field and the difference between turbulent heat flux model and constant turbulent Prandtl number model are described by showing the distributions of Nusselt number.

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Attributes of visual displays in vehicle are critical factors to give drivers safety information adequately. The aim of this study was to investigate effects of attributes of the visual displays on drivers' impression and readability of the information. Questionnaire and a laboratory experiment are conducted a survey to solve this aim. The result of factor analysis showed that four factors existed under drivers' impression of the displays; readability, attractiveness of display, priority of information, feeling of accuracy. Those impressions were influenced by amount of information, colors, attention expression by letters. The result of the laboratory experiment revealed that amount of information had effects on readability of information. Amount of information and colors are important factor to design visual displays in vehicle.

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What factor how contributed to the gap between on-road real fuel economy and certified (catalog) fuel economy of passenger cars was analyzed and understood quantitatively by using data that united the index of result of the questionnaire concerning the execution condition of the ecodriving and meteorological elements, etc. for the on-road real fuel economy self-reported by drivers. As a result of the analysis, the potential of ecodriving of the on-road real fuel economy improvement was clarified.

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This paper addresses a method of unusual driving behavior detection based on naturalistic driving database in urban area. This contributes to the development of an active safety system such as advisory and warning devices to prevent accidents in early stages. Naturalistic driving behavior data in real-world traffic situation is the key point of good cooperative characteristics between driver and driver assistance system. On-road experiments are conducted to capture the data by using continuous sensing drive recorder. The acceleration during pedal operation and time headway during following situation are analyzed to understand the differences of these feature values in running speed region, road environment and driver. In addition, the feature values in hurry driving classified by the distinctive factor are analyzed compared to usual driving data.

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Recently, the technology of safety driving and cruise assistance services has been being introduced in many ITS devices. By the increased number of vehicles with ITS devices, there would be traffic conditions where both vehicles with and without ITS devices are running in the road environment. In this study, influences toward driver behavior of following vehicles when preceding vehicles had either ITS devices or not was examined using a driving simulator. Comparative evaluation was also conducted between in-vehicle ITS device and variable message sign on roadside when safe driving and cruise assistance services were given to driver.

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This paper proposes a method for detecting deviation of driving behavior that a driver is going to execute from usual driving behavior in that situation for the purpose of preventing accidents caused by human error. The method is applied to a problem of detecting deviation from usual right-turn behavior of an oncoming vehicle in the opposite lane at an intersection. And, the performance of the method is evaluated with an experiment on a driving simulator.

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We propose face orientation estimation system to detect driver's behavior at the intersection. At first, we detected driver's face and face parts from images shooted by near infrared camera on the dashboard in the car. And then, estimated face orientation using detected face parts positions, 3D face model and particle filter. We show the algorithm of face and face parts detection by SVM(Support Vector Machine) and face parts tracking and orientation estimation by particle filter and also show the result of estimation

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In this study, we conducted hydrogen gas filling tests to examine thermal behavior in hydrogen storage tank. In all previous test, we tested only a storage tank. Therefore, we conducted fast filling test with the storage system which is assumed to confirm the effectiveness of the previous test data, and to examine influence of components and constraction of components. As a result, it was confirmed that we could utilize the previous test data. On the other hand, it is feared that pressure between tanks will be unbalanced when we use tanks that show different thermal behavior as a storage system.

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