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721.
J. N. Han N. J. Cho S. W. Chae Y. Choi 《International Journal of Automotive Technology》2008,9(5):633-640
A hybrid mesh generation algorithm using a modified plastering method for three-dimensional objects with variable thickness
is presented. The method starts with a quad-dominant surface mesh and generates layered elements with variable thickness by
using adaptive offsetting, resulting in hex-tet dominant mesh generation. Hexahedral and prismatic meshes are generated by
the inward offsetting of the initial boundary mesh. In order to generate a conforming mesh, pyramid elements are constructed
on top of hexahedral elements, and tetrahedral elements are generated for the remaining domain by using an advancing front
method. This method is applied to several different geometries, and the effectiveness of the proposed algorithm is demonstrated. 相似文献
722.
Prediction of interior noise by excitation force of the powertrain based on hybrid transfer path analysis 总被引:1,自引:0,他引:1
In the early design stage of a vehicle, simulation of interior noise is useful for assessment and enhancement of the noise,
vibration and harshness (NVH) performance. Traditional transfer path analysis (TPA) technology cannot simulate interior noise
since it uses an experimental method. In order to solve this problem, hybrid TPA is employed in this paper. Hybrid TPA uses
simulated excitation force as the input force, which excites the flexible body of a car at the mount points, while traditional
TPA uses the measured force. This simulated force is obtained by numerical analysis of the finite element (FE) model of a
powertrain. Interior noise is predicted by multiplying the simulated force by the vibro-acoustic transfer function (VATF)
of the vehicle. The VATF is the acoustic response in the compartment of a car to the input force at the mount point of the
powertrain in the flexible car body. The trend of the predicted interior noise based on the hybrid TPA corresponds very well
to the measured interior noise, with some difference due to not only experimental error and simulation error, but also the
effect of the airborne path. 相似文献
723.
Experimental study of the physical and chemical characteristics of biodiesel blended fuel using ultrasonic energy irradiation 总被引:1,自引:0,他引:1
The purpose of this study is to understand the physical and chemical characteristics of biodiesel blended fuel reformed by
ultrasonic energy irradiation. To do this, a mixture of commercial diesel fuel and biodiesel was compared and analyzed according
to whether or not ultrasonic energy irradiation was performed and the duration of irradiation. The results of the experiments
indicate that when ultrasonic energy irradiation was performed on biodiesel blended fuel, its viscosity decreased by 3–7%.
In the case of BD20, when ultrasonic energy irradiation was performed, its Sauter mean diameter (SMD) dropped by 12% on average.
As the irradiation duration increased, the volume ratio of olefins increased up to a maximum of 2.7%, and the higher heating
value increased to a maximum of 5.8%. On the contrary, the ratio of aromatics decreased by a maximum of 2.7%, and BI decreased
by a maximum of 7%. 相似文献
724.
串列双圆柱尾迹流的数值分析 总被引:1,自引:0,他引:1
为避免流体流动引起共振,采用有限体积法,对串列双圆柱尾迹流进行了数值分析,探讨了斯特劳哈尔数(Strouhal数)随圆柱间距比和雷诺数变化的规律.研究表明:在不同流场形态下,斯特劳哈尔数随圆柱间距比的变化规律不同;斯特劳哈尔数随雷诺数的增大而增大,但增大幅度与流场形态有关. 相似文献
725.
Relationships between characteristics of motorcycles and hydrocarbon emissions in Taiwan: A note 总被引:1,自引:0,他引:1
C.W. Lin Y.R. Chen S.J. Lu S.W. Cho K.S. Lin Y.C. Chiu X.Y. Tang 《Transportation Research Part D: Transport and Environment》2008,13(5):351-354
Taiwan’s inspection and maintenance (I/M) programs identifies high-emission motorcycles but, although these help reduce air pollution, they have been criticized for being cost-ineffective. This study examines the relationship between characteristics of motorcycles and hydrocarbon emissions in the Central Air Quality Basin of Taiwan. It is shown that engine size and type, age and manufacturer of a motorcycle significantly affect HC emissions. Larger-size engines emit smaller amounts of HCs; whereas older motorcycles emitted greater amounts. In addition, two-stroke-engine machines produced significantly higher HC emission levels than four-strokes. Variations in HC emissions testing are a result of various I/M testing locations and efficiency may be improved by modifying these. 相似文献
726.
B. Liu T.X. Mei S. Bruni 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(3):429-444
This paper describes a study for the optimisation of the wheel profile in the wheel–rail system to increase the overall level of adhesion available at the contact interface, in particular to investigate how the wheel and rail profile combination may be designed to ensure the improved delivery of tractive/braking forces even in poor contact conditions. The research focuses on the geometric combination of both wheel and rail profiles to establish how the contact interface may be optimised to increase the adhesion level, but also to investigate how the change in the property of the contact mechanics at the wheel–rail interface may also lead to changes in the vehicle dynamic behaviour. 相似文献
727.
S. H. Yoo N. T. Jeong K. S. Kim S. M. Yang J. H. Lee S. H. Choi M. W. Suh 《International Journal of Automotive Technology》2016,17(4):681-687
The use of plastic in vehicle development has increased. In particular, a design trend has resulted in chromiumplated plastics being used in exterior panels. Recently, as the appearance has become more important in design, the plastic radiator grille has become larger, to where it can become the primary member when a front collision happens. The radiator grille should be designed with considerations of the geometric structure, such as delamination, and material characteristics, when plastics are plated with chromium. The enlarged grille has to pass regulations like FMVSS Part 581. Although the material property of plastic has been studied before, what seems to be lacking is study on the crashworthiness of plastic radiator grilles that are plated using chromium. In this paper, in order to evaluate the crashworthiness, tensile test and front collision analysis using finite element method are performed. Tensile test is conducted with 4 types of materials, and then material properties of chromium-plated plastics are obtained. Meanwhile radiator grille’s crashworthiness is evaluated using finite element analysis method. Analysis result is evaluated according to failure criterion. Through this study, method of the assessment of plastic radiator grille’s crashworthiness considered material properties of chromium plated plastics is proposed, and it can be predicted the delamination and the failure point of radiator grille at the design step. 相似文献
728.
Some gears in an automobile transmission have to be mounted by being press-fitted on a shaft instead of splines. The torque capacity of the press-fitted gear will be proportional to the radial interference. The excessive interference, however, will increase the gear radial deformation. In this paper, the press- and shrink-fit and the subsequent torque capacity test were investigated by finite element analysis, theoretically and experimentally. The static and dynamic coefficient of friction were determined. 相似文献
729.
This paper presents a fault-tolerant brake torque controller for four-wheel-distributed braking systems with in-wheel motors and Electro-Mechanical Brakes (EMB). Mechanical and electrical faults can degrade the performance of the EMB actuators and, thus, their effects need to be compensated in vehicle dynamics level. In this study, the faults are identified as performance degradation and expressed by the gains of each actuator. Assuming the brake force distribution and the regenerative braking ratios, the over-actuated braking system is simplified into a two-input system. A sliding mode controller is designed to track the driver’s braking and steering commands, even if there exist faults in EMBs. In addition, adaptive schemes are constructed to achieve the fault-tolerant control in braking. The proposed controller and strategies are verified in the EMB HILS (Hardware-in-loop-simulation) unit for various conditions. 相似文献
730.
This study proposes a design for an idle speed controller to compensate for varying engine load and friction torque in passenger car diesel engines. An active disturbance rejection control (ADRC) framework, comprised of a disturbance compensator and a feedback controller, is applied to an idle speed controller to compensate for disturbances such as engine load and friction torque. In addition, a feedforward compensator is designed into the ADRC framework to improve disturbance rejection performance. The proposed controller is validated by engine and vehicle experiments and the experiment results are compared with a commercial controller. 相似文献