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排序方式: 共有446条查询结果,搜索用时 15 毫秒
101.
Jinseong Kim Gisu Kim Yeong-il Park 《International Journal of Automotive Technology》2018,19(4):743-749
In designing a parallel hybrid electric vehicle, it is essential to select the optimal capacity of power sources and the optimal gear ratio of the torque coupler. The capacity of the power sources and the gear ratio of the torque coupler should be optimized simultaneously. However, since this process is excessively time-consuming, previous studies have selected the gear ratio of the torque coupler and then selected the capacity of power source. However, this approach cannot guarantee global optimization. In this paper, a feasible region is defined to satisfy the required performance of vehicle such as maximum speed, hill-climbing. and feasible points are selected inside the feasible region. In the conventional technique, the global optimal solution is obtained by simulating all feasible points. In the optimization technique, optimal points are simulated within the feasible region using several optimal search algorithms, such as the golden section search algorithm and the hillclimbing search algorithm. And using these algorithms, the number of simulations is reduced and the capacity of the power source and the gear ratio of the torque coupler are optimized simultaneously. Finally, the validity of the component sizing results is verified by comparing the global optimal solution obtained by applying the conventional technique with the solution obtained by applying the proposed optimization technique. 相似文献
102.
Jae Woo Chung Nam Ho Kim Deok Jin Kim Seong Sik Jang 《International Journal of Automotive Technology》2018,19(2):209-220
Recently, to improve vehicle fuel economy, as well as the performance of internal combustion engines, optimized system matching between a vehicle’s drivetrain and engine has become a very important technical issue. For this reason, the need for simulation research on engine and vehicle performance improvement has increased. But in general, since both engine simulation and vehicle simulation require initial engine calibration map input, a simple engine calibration method is required for the efficient configuration of various virtual engine calibration map setups. On this background, in this study, an example of waste gate turbocharger (WGT) cooled — exhaust gas recirculation (EGR) Diesel engine calibration using a test-based mean value engine model is presented as a suitable engine calibration map setting method. Also, the feasibility of an engine calibration model is confirmed through various engine tests. Using the simple model presented here, it is possible for diverse engine operating conditions and engine performance maps to be acquired. 相似文献
103.
J.-H. Kim J.-M. Seo J. H. Jung N.-K. Hur 《International Journal of Automotive Technology》2011,12(3):417-423
Manufacturers of commercial vehicles are facing a substantial increase of heat release into their cooling systems. The main
sources for this increase are more stringent emissions leading to new combustion technologies and the increased power of these
engines. The total increase in the cooling requirement may be up to 20% over the current level. At the same time, the noise
levels must be decreased, and fuel economy has to improve. This forces manufacturers to consider new concepts and optimize
the efficiency of the cooling system. A bus engine cooling fan system is one of the main means of vehicular fuel efficiency
reduction. This is becoming a major factor in city noise, and the necessity of electromagnetic technical development is very
great. This study features a highly effective BLDC motor for engine cooling fans with high effectiveness and low noise, which
is most suitable for fan blade technical development and cooling fan performance evaluation technical development. 相似文献
104.
S. H. Lee T. W. Park K. H. Chung K. H. Choi K. K. Kim K. H. Moon 《International Journal of Automotive Technology》2011,12(1):75-82
HILS (Hardware In the Loop Simulation) and RBT (Requirement-Based Testing) are widely used to evaluate the performance and
reliability of automotive ECUs (Electronic Control Units). The HILS method is used to predict the behavior of ECU-installed
vehicles and to evaluate the performance of ECU controllers. RBT evaluates whether the embedded system satisfies the pre-defined
requirements. In this study, the behavior of a vehicle is regarded as a system requirement, and an embedded system test procedure
that evaluates the system requirement is proposed. In particular, a new method is introduced, which integrates HILS with RBT.
Using the proposed method, the behavior of an articulated vehicle equipped with an AWS (All Wheel Steering) ECU is evaluated
with RBT software. 相似文献
105.
This paper describes a drive controller designed to improve the lateral vehicle stability and maneuverability of a 6-wheel
drive / 6-wheel steering (6WD/6WS) vehicle. The drive controller consists of upper and lower level controllers. The upper
level controller is based on sliding control theory and determines both front and middle steering angle, additional net yaw
moment, and longitudinal net force according to the reference velocity and steering angle of a manual drive, remotely controlled,
autonomous controller. The lower level controller takes the desired longitudinal net force, yaw moment, and tire force information
as inputs and determines the additional front steering angle and distributed longitudinal tire force on each wheel. This controller
is based on optimal distribution control and takes into consideration the friction circle related to the vertical tire force
and friction coefficient acting on the road and tire. Distributed longitudinal/lateral tire forces are determined as proportion
to the size of the friction circle according to changes in driving conditions. The response of the 6WD/6WS vehicle implemented
with this drive controller has been evaluated via computer simulations conducted using the Matlab/Simulink dynamic model.
Computer simulations of an open loop under turning conditions and a closed-loop driver model subjected to double lane change
have been conducted to demonstrate the improved performance of the proposed drive controller over that of a conventional DYC. 相似文献
106.
Torque control of engine clutch to improve the driving quality of hybrid electric vehicles 总被引:1,自引:0,他引:1
H. S. Hwang D. H. Yang H. K. Choi H. S. Kim S. H. Hwang 《International Journal of Automotive Technology》2011,12(5):763-768
As a powertrain for hybrid electric vehicles (HEVs), the automatic transmission (AT) is not only convenient for the driver
but also reduces hybridization costs because the existing production line is used to produce the AT. However, it has low fuel
economy due to the torque converter. To overcome this disadvantage, this paper studies HEVs equipped an AT without a torque
converter. In this case, additional torque control is needed to prevent the driving quality from deteriorating. This paper
suggests three different torque control methods and develops a simulator for an HEV that can simulate the dynamic behaviors
of the HEV when the engine clutch is engaged. The HEV drive train is modeled with AMESim, and a controller model is developed
with MATLAB/Simulink. A co-simulation environment is established. By using the developed HEV simulator, simulations are conducted
to analyze the dynamic behaviors of the HEV according to the control methods. 相似文献
107.
Jinggao Li I. Kim S. Lee S. Han C. Lee S. Cheon W. Lee K. An G. Cho J. Hwang D. Mun 《Journal of Marine Science and Technology》2011,16(1):76-83
In the shipbuilding industry, different computer-aided design (CAD) systems are used for different design domains, structure, and outfitting. We need to exchange data among different CAD systems such as Tribon, AutoCAD, Intergraph or PDMS to complete the whole design and production process. There are two approaches to data exchange. One is direct translation; the other is indirect translation, which is based on a neutral format. If we use a neutral format, the data specification is open to the public and the design model can be used by other CAD systems, including next-generation CAD systems. In this paper, we propose an indirect method that uses ISO 10303 (STandard for the Exchange of Product model data) AP227 and ISO 15926 to define neutral formats. A separate ShapeDB is constructed to manage the geometry information, referenced to the catalogue data defined by ISO 15926. An experimental implementation for data exchange between Tribon and PDMS is described. 相似文献
108.
Quantitative assessment of hydrocarbon explosion and fire risks in offshore installations 总被引:1,自引:0,他引:1
Jeom Kee Paik Jerzy CzujkoBong Ju Kim Jung Kwan SeoHan Seong Ryu Yeon Chul HaPiotr Janiszewski Beata Musial 《Marine Structures》2011,24(2):73-96
A risk-based design framework should involve both risk assessment and risk management. This article introduces and describes a number of procedures for the quantitative assessment and management of fire and gas explosion risks in offshore installations. These procedures were developed in a joint industry project on the explosion and fire engineering of floating, production, storage and off-loading units (the EFEF JIP), which was led by the authors. The present article reports partial results, focussing on defining the frequency of fires and explosions in offshore installations. Examples of the aforementioned procedures’ application to a hypothetical floating, production, storage, and off-loading unit (FPSO) are presented. A framework for the quantitative risk assessment of fires and explosions requires the definition of both the frequency and consequences of such events. These procedures can be efficiently applied in offshore development projects, and the application includes the assessment of design explosion and fire loads as well as the quantification of effects of risk control options (RCO) such as platform layout, location and number of gas detectors, isolation of ignition sources etc. 相似文献
109.
Sang-Yeob Kim Kyong-Hwan Kim Yonghwan Kim 《Journal of Marine Science and Technology》2012,17(1):47-58
This paper considers a comparative study on model-scale sloshing tests. There are two primary scopes of this study: the comparison
of sloshing pressure measured in 1/50-scale model tests at Seoul National University (SNU) with (1) the data measured at the
other facility for the same model, and (2) the data measured on a smaller scale model. For the comparative study, model tanks
are excited with the same irregular motions with Froude scale, and sloshing pressure signals are measured at the same locations.
The statistical quantities of 1/50-scale model tests are compared with those of other facility and 1/70-scale model tests.
In this study, it is found that peak pressure measured at SNU are slightly lower than those of other facility, and this difference
may be due to different sensor types and sensing diameters. 相似文献
110.
S. O. Kang S. O. Jun H. I. Park K. S. Song J. D. Kee K. H. Kim D. H. Lee 《International Journal of Automotive Technology》2012,13(4):583-592
This research aims to develop an actively translating rear diffuser device to reduce the aerodynamic drag experienced by passenger cars. One of the features of the device is that it is ordinarily hidden under the rear bumper but slips out backward only under high-speed driving conditions. In this study, a movable arc-shaped semi-diffuser device, round in form, is designed to maintain the streamlined automobile??s rear underbody configuration. The device is installed in the rear bumper section of a passenger car. Seven types of rear diffuser devices whose positions and protrusive lengths and widths are different (with the basic shape being identical) were installed, and Computational Fluid Dynamics (CFD) analyses were performed under moving ground and rotating wheel conditions. The main purpose of this study is to explain the aerodynamic drag reduction mechanism of a passenger car cruising at high speed via an actively translating rear diffuser device. The base pressure of the passenger car is increased by deploying the rear diffuser device, which then prevents the low-pressure air coming through the underbody from directly soaring up to the rear surface of the trunk. At the same time, the device generates a diffusing process that lowers the velocity but raises the pressure of the underbody flow, bringing about aerodynamic drag reduction. Finally, the automobile??s aerodynamic drag is reduced by an average of more than 4%, which helps to improve the constant speed fuel efficiency by approximately 2% at a range of driving speeds exceeding 70 km/h. 相似文献