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821.
Hydraulically damped rubber mount (HDM) can effectively attenuate vibrations transmitted between an automotive powertrain and body/chassis and reduce interior noise in the car compartment. Predicting the dynamic characteristics of a HDM faces challenges due to fluid-structure interactions between the rubber spring and fluid in the chambers, nonlinear material properties of the rubber parts and turbulent flow in the chambers and fluid track linking chambers. In this paper, an experimental analysis and hydrostatic finite element (FE) modeling technique are integrated in a numerical simulation approach to modeling the dynamic characteristics of a HDM with a lumped-parameter HDM model. The dynamic characteristics of a typical HDM with a fixed decoupler are predicted and compared with experimental results, which verify the effectiveness of the proposed approach. Moreover, a parametric effect analysis is performed to demonstrate parameter influence on dynamic characteristic, which provides a concise design guideline for the parameter adjustments necessary for a HDM to meet the vibration isolation requirements of a powertrain mount system. 相似文献
822.
S. M. Park T. W. Park S. H. Lee S. W. Han S. K. Kwon 《International Journal of Automotive Technology》2010,11(1):49-56
In this study, a new concept for a power delivery system is developed. Power Shift Drive (PSD) Axle vehicle modeling and dynamic movement analysis are performed via simulation. The dynamic vehicle model is constructed from data obtained from the derived equation, considering the specific characteristics of each part. The model is composed of a torque converter, a gear box, a differential, hub reduction and an engine, which is the power source of the 1st forward and reverse PSD-Axle. By unifying the mathematical equations for each component, a mathematical model of the 1st forward gear is derived. The system dynamic model is created using MATLAB/Simulink based on the mathematical model. Simulation is carried out using Simulink to estimate the dynamic behavior of the PSD-Axle. In addition, the dynamo test result is used to verify the model. Finally, a successful model is created. This study will be used to establish the basic conceptual design for the PSD-Axle multi-gear system. 相似文献
823.
S. Lee D. H. Lee M. H. Kim K. C. Lee 《International Journal of Automotive Technology》2010,11(4):525-531
The controller area network (CAN) is the dominant protocol for in-vehicle network (IVN) systems because it provides bounded transmission delay among electronic control units (ECUs) at data rates between 100 Kbps and 1 Mbps. Many automotive companies have chosen the CAN protocol for their chassis network system of intelligent vehicles. However, the increasing number of ECUs in intelligent vehicles and the need for more intelligent functions require a network system with more network capacity and real-time capability. As one approach to enhance the network capacity of a CAN system, this paper introduces a CAN system with dual communication channels. This paper also presents a traffic-balancing algorithm that predicts the traffic of each channel and allocates frames to the most appropriate channel. An experimental testbed using commercial off-the-shelf microcontrollers with two CAN controllers was used to demonstrate the feasibility of the traffic-balancing algorithm. 相似文献
824.
沥青混合料烟雾与材料力学性能之间的关系 总被引：1，自引：0，他引：1
着重于研究热拌沥青混合料生产过程中产生的烟雾与沥青力学性能之间的关系,涉及的影响因素有温度、沥青种类以及一些动力学参数。研究者在试验室拌和机上安装了气体取样设备,能够在正常拌和的同时对热拌沥青混合料烟雾中的多环芳香烃(PAH)以及有机化合物(TOC)进行取样分析。通过对沥青材料进行室内性能指标的测试,发现在所有指标中回收沥青的复合模量与沥青烟雾排放量的相关性最好,因为它的结果同时反映了材料的物理性能以及沥青氧化和老化的程度。同时还建立了热拌沥青混合料烟雾排放与拌和参数以及混合料力学性能之间的关系。 相似文献
825.
Mechanisms with “negative” stiffness are a unique tool used to significantly improve vibration isolation for a vehicle driver via upgrade of the seat suspension. However, connection of such mechanisms to the suspension results in errors in the function generation process, and in most cases, makes motion impossible. An approach to type synthesis is presented in order to make this process more predictable, easy and thus more practical for the upgrade process. Structural classification of the suspensions is presented, and -an atlas of function-generating mechanisms for suspensions that reveals the effect of “negative” stiffness is completed. All of the function-generating mechanisms appear in the atlas as result of enumeration. Structural properties of novel and existing mechanisms are compared. Finally, some advantages in practical use of novel suspensions with “negative” stiffness are illustrated. 相似文献
826.
H. S. Kook S. R. Shin K. D. Ih D. B. Kim D. H. Yu 《International Journal of Automotive Technology》2009,10(1):55-63
The large-scale shear flows over the sunroof opening of a mid-sized SUV measured using a PIV system were investigated. The shear flows were measured for five different cases of deflector protrusion (one case was the baseline test without deflector) at two different free stream flow velocities below the critical velocity where the buffeting noise level reached a maximum. The structures of the shear flows were observed to differ, apparently depending on whether the radiated buffeting noise is relatively strong or not. For strongly buffeting experimental cases, the momentum thicknesses of the shear layers were observed to grow rapidly and saturated at a station near the downstream edge of the sunroof opening, where the saturation of the transverse velocity fluctuations was also observed, and where the vortex coalescence process was presumably completed. On the other hand, no discrete large-scale vortex structures were observed for none-buffeting or weakly buffeting cases. Streamwise growth of the velocity fluctuations was found to be well predicted by a linear hydrodynamic instability analysis for the strongly buffeting cases. Numerical results obtained from a linear inviscid instability analysis using a hyperbolic tangent mean velocity profile were used to calculate the amplification factors with the initial momentum thickness and the streamwise fluctuation wavenumber. The shear flows were found to form large-scale discrete vortices when the linear inviscid amplification factors exceeded a threshold amplification factor. 相似文献
827.
A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future. 相似文献
828.
Y. T. Son B. Y. Kim K. J. Park H. Y. Lee H. J. Kim M. W. Suh 《International Journal of Automotive Technology》2009,10(5):635-644
To guarantee the efficiency of maintenance strategies for a complex structure, safety and cost limitations must be considered. This research introduces RCM-based (Reliability Centered Maintenance) life cycle optimization for reasonable maintenance. The design variable is the reliability of each part, which consists of a complex structure, while the objective is to minimize the total cost function in order to maintain the system within the desired system reliability. This research constructs the cost function that can reflect the current operating condition and maintenance characteristics of individual parts by generating essential cost factors. To identify the optimal reliability of each component in a system, this paper uses a Neuro-Evolutionary technique. Additionally, this research analyzes the reliability growth of a system by using the AMSAA (Army Material Systems Analysis Activity) model to estimate the failure rate of each part. The MTBF (Mean Time Between Failure) and the failure rate of the whole system, which is responding to the individual parts, are estimated based on the history data by using neural networks. Finally, this paper presents the optimal life cycle of a complex structure by applying the optimal reliability and the estimated MTBF to the RAMS (Reliability, Availability, Maintainability, and Safety) algorithm. 相似文献
829.
For planning and design of a bus rapid transit system and for the analysis of multimodal corridors, methodology is required for simulating bus traffic operation on a Transitway. Macroscopic models of vehicle flow are gaining popularity due to their capability to analyze complex operations and yet offer efficiency in development and applications. A macroscopic model is developed for the investigation of travel time, energy and emissions that correspond to bus volume levels on the Transitway. This paper describes the travel time part of the model. The model treats stochastic characteristics of bus traffic and passenger activities. Also, safety regimes in vehicle flow and factors affecting minimum headways in station areas are incorporated. The model is verified by comparing simulated travel time for the Ottawa-Carleton Transitway with actual data. 相似文献
830.
W.X. Wu B.V. Brickle J.H. Smith R.K. Luo 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1998,30(3):229-236
A model for the numerical simulation of vehicle/track interaction and stick-slip vibration is presented. A finite element model is developed to calculate vertical contact forces. These forces are then coupled through the contact patch into a non-linear time-domain model by which the stick-slip vibration behaviour of a wheel-rail system is analysed. The investigation suggests that stick-slip vibration may occur if a vehicle which has a maligned or an initial 'wind-up' wheeiset meets a vertical irregularity or contaminants on the track. 相似文献