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Modeling and Validation for the Hysteretic Behavior of an Automatic Belt Tensioner

South China University of Technology-Shangbin Long, Xuezhi Zhao, Wen-Bin Shangguan
BYD Auto Industry Company Limited-Pu Xu
Published 2019-06-05 by SAE International in United States
An automatic tensioner used in an engine front end accessory drive system (EFEADS) is taken as a study example in this paper. The working torque of the tensioner, which consists of the spring torque caused by a torsional spring and the frictional torques caused by the contact pairs, is analyzed by a mathematic analysis method and a finite element method. And the calculation and simulation are validated by a torque measurement versus angular displacement of a tensioner arm. The working torques of the tensioner under a loading and an unloading process are described by a bilinear hysteretic model, and are written as a function with a damping ratio. The rule of the action for the damping devices is investigated based on the simulation and a durability test of the tensioner. A finite element method for the tensioner without damping device is established. Then the radial deformation for the torsional spring under an unconstrained state is obtained. The analysis results have a good correlation with the measurements. The method presented in this paper is beneficial for…
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Fault Feature Extraction of Elliptically Shaped Bearing Raceway

South China University of Technology-Yingying Guo, Xuezhi Zhao
Published 2019-06-05 by SAE International in United States
The elliptically shaped bearing (ESB) with a rigid, elliptical inner race and a flexible, thin-walled outer race is the most easily damaged core component of harmonic drive. The ESB rotates under cycle load of alternating stress due to its special elliptic structure. Hence, the fault features of ESB such as fatigue spalling and pitting are apt to be concealed by the excitation of impulses caused by alternating between major axis and minor axis. In order to diagnose the fault on raceway surfaces of ESB, a new method of CMWT-FH based on Continuous Morlet Wavelet Transform (CMWT) and FFT-based Hilbert (FH) spectrum analysis is proposed to extract the fault feature. First, the formulas of feature frequency is deduced based on the geometry and kinematics characteristics of ESB; then the CMWT method is employed to decompose the fault signal of ESB; finally, the FH spectrum analysis is performed to extract the feature frequency of faulty ESB from the decomposition signal with the maximum kurtosis in the first several layers. Compared with the traditional FH method, the feature…
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A Novel Kind of Proportional Electromagnetic Dynamic Vibration Absorber

South China University of Technology-Tao FU
Published 2019-06-05 by SAE International in United States
A new proportional electromagnetic dynamic vibration absorber (EDVA) is proposed for control of engine vibration during idling. The device consists of an electromagnetic actuator attached to the primary structure through elastic element, where the driving force pair is implemented between the reaction-mass and the primary structure. The design of the proportional electromagnetic actuator is realized considering the geometric parameters of the core to achieve nearly constant magnetic force over a broad range of its dynamic displacement but proportional to square of the current. A methodology is proposed to achieve magnetic force proportional to square of current and consistent with the disturbance frequency. The proportional EDVA is subsequently applied to a single-degree-of-freedom primary system with an acceleration feedback control algorithm for attenuation of primary system vibration in a frequency band around the typical idling vibration frequencies. The effectiveness of the hybrid proportional EDVA is evaluated through simulations and laboratory experiments under harmonic excitations in the 20-30 Hz frequency range. Both the simulation and measurements show that the hybrid proportional EDVA can yield effective attenuation of periodic…
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Kinematic Analysis and Simulation of the Double Roller Tripod Joint

South China University of Technology-Yinyuan Qiu, Wen-Bin Shangguan
Published 2019-06-05 by SAE International in United States
The kinematic model of the double roller tripod joint is established in order to analyze its kinematic characteristics and provide theoretical basis for its application and improvement. By means of spatial coordinate transformation, the translational and rotational motion equations of the rollers relative to the tracks and trunnions, the motion equation of the center of the tripod and the equations of the input/output angular displacement error and bending angle are derived. The motion simulation of the double roller tripod universal joint was carried out in ADAMS so as to verify the established kinematic model. The results show that the rollers of the double roller tripod joint only have periodic translational motions relative to the tracks while the rollers have both periodic translational and rotational motions relative to the trunnions. The tripod’s center does the circular motion on the tripod plane with the angular velocity 3 times of the input angular velocity. The input/output angular displacement error and bending angle have volatility, and their fluctuating frequency are 3 times of the input rotational frequency. Hence, the…
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A Control Strategy to Reduce Torque Oscillation of the Electric Power Steering System

South China University of Technology-Duo Fu, Wen-Jun Yan, Wen-Bin Shangguan
Concordia University Montreal-Subhash Rakheja
Published 2019-06-05 by SAE International in United States
This paper proposes a new evaluation method of analyzing stability and design of a controller for an electric power steering (EPS) system. The main purpose of the EPS system’s control design is to ensure a comfortable driving experience of drivers, which mainly depends on the assist torque map. However, the high level of assist gain and its nonlinearity may cause oscillation, divergence and instability to the steering systems. Therefore, an EPS system needs to have an extra stability controller to eliminate the side effect of assist gain on system stability and attenuate the unpleasant vibration. In this paper, an accurate theoretical model is built and the method for evaluating system quality are suggested. The bench tests and vehicle experiments are carried out to verify the theoretical analysis. The evaluation method proposed in this paper can not only guide the design of controller parameters, but also evaluate the control effect while the performance of several controllers are all excellent.
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Interior Sound Quality Refinement Base on Mechanism Study of Crankshaft Impact Noise

South China University of Technology-Xuelu Cao
GAC Automotive Engineering Institute-Zhangming Su, Hanshuang Chen, Qi Yang, Dandan Kong, Weizhe Xing, Yanghui Xu
Published 2019-04-02 by SAE International in United States
A rumbling noise is audible in a vehicle passenger compartment during acceleration. Mechanism detail of the rumbling noise is studied. A series of preliminary transfer path experiments investigation on chassis dynamometer shows that the interior rumbling noise is mainly induced by abnormal crankshaft impact at particular crank angle. Spectrum analysis indicates that high level half order harmonic components significantly affects the rumbling noise. Multi-body dynamics model of the powertrain is developed to further investigate the root cause of the abnormal crankshaft impact. Experiment results are used to verify the numeric model. High deviation of main bearing forces at the crank angle 0° to 180° after the Fire Top Dead Center of the no.l cylinder is considered to fundamentally induces the high level half order components. The force ripple coupled with the crankshaft resonance induces the crankshaft rumbling. Sensitivities analysis of various bearing seat structure, crankshaft structural parameters were carried out. The ladder frame, a stiffened crankshaft with bigger overlap and shortened the front end offset distance seem effectively reduce the rumbling impact and improve interior…
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Analysis and Simulation of Low-Speed Collision of Car Front Bumpers

South China University of Technology-Min Li, Wenbin Shangguan
Zhuzhou Times New Material Technology Co. Ltd.-Zhangyang Xia
Published 2018-04-03 by SAE International in United States
Bumper systems are vital to improving automotive passive safety and reducing the maintenance cost in low-speed collision. Automotive companies need to develop bumpers with adequate strength, high energy absorption rate, minimum weight and least expense. To shorten the product development period and lower the development cost, four evaluation conditions were proposed to assess the behaviors of car front bumpers based on the three main low-speed collision regulations of the US Part 581, the Canadian CFVSS215 and the European ECE-R42. A finite element method was put forward to model the car front bumper and to analyze the low-speed collision performance of the bumper system. A drop hammer impact test was carried out to verify the validity of the method, and experiment results indicated the correctness of the finite element model. The dynamic response and the energy absorption parameters of the bumper system were calculated, including structural deformation, collision force and energy absorption ratio. The maximum longitudinal deformation and the energy absorption ratio were chosen as the evaluation standards to determine whether the bumper meets the collision…
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Effect of Magnetic Nanorefrigerant on Electric Vehicle

South China University of Technology-ZhenYang Liu, Xihui Wang
Published 2017-10-08 by SAE International in United States
The ever increasing popularity of electric vehicles and higher requirement on safety and comfort has led heat pump air conditioning system indispensable in electric vehicle. Many studies have shown that the addition of nano particles contributes to great improvement on thermal conductivity than that of conventional refrigerants. Therefore, the application of the magnetic nanorefrigerant in heat pump air conditioning system has massive potential to heighten the heat transfer efficiency. This paper aims at studying the magnetic nanorefrigerant comprised of the magnetic nano powder Fe3O4 and refrigerant R134a. According to the relevant theoretical analyses and empirical formula, the heat transfer coefficient, density, viscosity, and other physical parameters are calculated approximately. In the heat pump air conditioning system of a certain type of electric vehicle, the special working condition parameters are selected to carry out calculation analysis with numerical analysis software. The results show that the heat exchange amount of this nanorefrigerant is 21.23% higher than the pure refrigerant R134a and increases with the volume fraction of the nano particles. Moreover, after adding Fe3O4 nano materials to…
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Study on Steering Angle Input during the Automated Lane Change of Electric Vehicle

South China University of Technology-Hongluo Li, Yutao Luo
Published 2017-09-23 by SAE International in United States
The trajectory planning and the accurate path tracking are the two key technologies to realize the intelligent driving. The research of the steering wheel angle plays an important role in the path tracking. The purpose of this study is to optimize the steering wheel angle input during the automated lane changing. A dynamic programming approach to trajectory planning is proposed in this study, which is expected to not only achieve a quick reaction to the changing driving environment, but also optimize the balance between vehicle performance and driving efficiency. First of all, the lane changing trajectory is planned based on the positive and negative trapezoidal lateral acceleration method. In addition, the multi-objective optimization function is built which includes such indexes: lateral acceleration, lateral acceleration rate, yaw rate, lane changing time and lane changing distance. The fuzzy logic controller is designed to distribute the weight coefficient in multi-objective function, which can adapt to different real situations. Subsequently, the optimal steering angle can be derived when the obtained optimum trajectory curve is used as the input of…
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Design of Powertrain Mounting System for Engine with Three Cylinders

South China University of Technology-Xiao-Ang Liu, Wenbin Shangguan
TDC, SAIC GM Wuling Automobile Co., Ltd.-Zhaoping Lv
Published 2015-06-15 by SAE International in United States
The inline 3-cylinder engine is taken as an object, the imbalance resultant rotating inertia moment and resultant reciprocating inertia moment generated by piston-crank mechanisms are analyzed. The balance theories of two different balance methods are presented and the additional moment generated through each method is derived. Three different balance conditions are proposed. The imbalance moments and mount reaction forces in each condition are calculated and compared. The powertrain mounting system design method is developed. The optimal mount stiffness not only satisfy the powertrain's natural frequencies and energy distributions but also meet the requirement for mount reaction forces in “50% balance condition”.
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