Table of Content

25 December 2019, Volume 41 Issue 12 Previous Issue    Next Issue

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Research on Energy Management Strategy of Fuel Cell Vehicle Based on Fuzzy Logic Control Wang Qian, Li Dinggen, Miao Huachun 2019, 41 (12):  1347-1355.  doi: 10.19562/j.chinasae.qcgc.2019.012.001 Abstract ( 576 )   PDF (2802KB) ( 869 )   Save For the problem of shortened service life of the fuel cell vehicle due to frequent over-discharge and the rapid increase of economic cost caused by high power demand module, a control strategy model of energy management for fuel cell compensated power battery discharge based on micro-variable fuzzy logic control is proposed by combining fuel cell vehicle with power battery module. Through the secondary development and optimization of ADVISOR, the simulation results verify the rationality of the energy management control strategy of the fuel cell-battery hybrid model, which ensures the power and economic performance of the vehicle. In addition, the total energy utilization efficiency of the system at the end of the driving cycle is optimized. The results show that the fuel cell-battery hybrid vehicle based on micro-variable fuzzy logic control meets the requirements of power and the economic performance is improved. References | Related Articles | Metrics

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Research on Hybrid Mode Transition Control with Engine Start Yang Ye, Zhang Youtong, Shan Xiaoming 2019, 41 (12):  1356-1364.  doi: 10.19562/j.chinasae.qcgc.2019.012.002 Abstract ( 276 )   PDF (1538KB) ( 525 )   Save Plug-in hybrid electric buses have two kinds of power sources. Switching between different power sources will lead to longitudinal impact, which will affect the power and comfort of the vehicle. Taking the coaxial parallel hybrid bus as the research object, the dynamic switching process from pure electric mode to hybrid drive mode is analyzed. Based on state space theory, the mode conversion process is divided into four sub-states, and the dynamic coordinated control strategy is designed. Taking the longitudinal impact and mode switching time of vehicle running as evaluation indexes, the proposed dynamic coordinated control strategy is verified by bench test and is compared with the traditional motor torque compensation strategy. The results show that the designed control strategy can effectively suppress the speed fluctuation, shorten the mode switching time, reduce the longitudinal impact, and improve the driving performance. References | Related Articles | Metrics

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Study on Passive Regeneration Characteristics and Regeneration Balance Condition of CDPF Chu Guoliang, Wang Guoyang, Qi Jinzhu, Yang Bo, Shuai Shijin 2019, 41 (12):  1365-1369.  doi: 10.19562/j.chinasae.qcgc.2019.012.003 Abstract ( 286 )   PDF (865KB) ( 550 )   Save Based on Arrhenius equation, a chemical reaction model for passive regeneration of catalyzed diesel particulate filter (CDPF) is established and then calibrated and verified by the bench test on a heavy-duty diesel engine. The calibrated model can well predict the reaction rate of soot oxidation by NO2 in CDPF. Results show that soot oxidation rate, i.e. passive regeneration rate rises with the increases of the soot loading and temperature of CDPF, and under the operation condition of a 3.8 g/L soot loading and a 550×10-6 NOx concentration, the balance temperature of CDPF is around 283 ℃. Higher NOx emission is beneficial to CDPF passive regeneration and can reduce the soot loading and temperature at DCPF balance point. The regeneration balance curve depends on the preset soot loading of CDPF, as the preset soot loading increases, the regeneration balance curve moves downward, and hence the passive regeneration region enlarges. References | Related Articles | Metrics

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Study on Counterflow Mixer Design and Urea Crystallization Risk Assessment Method Han Feng, Zhang Xiaoli, Wang Yibao, Hu Xiaoyan, Wang Xia, Shi Dailong 2019, 41 (12):  1370-1376.  doi: 10.19562/j.chinasae.qcgc.2019.012.004 Abstract ( 245 )   PDF (2359KB) ( 441 )   Save Urea crystallization is easy to form on the wall of traditional double-tube SCR mixer at low exhaust temperature condition. In order to solve this problem, a new type of counter-flow SCR mixer and its integrated layout scheme with nozzle seat are designed in this paper. By combining CFD technology and bench test, the anti-urea crystallization ability of the counterflow mixer as well as its influence on NOx emission is verified. The mechanism and risk assessment of urea crystallization are studied in depth. The method based on urea crystallization Excess Energy Ratio (EER) is proposed to compare urea crystallization risk under different operating conditions. The emission test in transient state and 30 h engine bench test on urea crystallization of the counterflow SCR catalytic converter are conducted. The bench test results show that the transient conversion efficiency of nitrogen oxides of the counter-flow mixer has increased by 1.8% while the 30 h bench test results show that no urea crystallization appear on the wall of the counter-flow mixer. References | Related Articles | Metrics

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RUL Prediction of Lithium-ion Battery Based on Improved Particle Filtering Algorithm Wei Haiyan, An Jingjing, Chen Jing, Wang Huimin, Pan Haihong, Chen Lin 2019, 41 (12):  1377-1383.  doi: 10.19562/j.chinasae.qcgc.2019.012.005 Abstract ( 323 )   PDF (1218KB) ( 628 )   Save When using traditional particle filtering (PF) algorithm to predict the remaining useful life (RUL) of lithium-ion battery, a phenomenon of losing particle diversity occurs, leading to low accuracy in RUL prediction. In view of this, an idea of linear optimization resampling is introduced to establish a battery RUL prediction method based on linear optimization resampling particle filtering (LORPF). The method adopts the double exponential model as battery aging model, and the model parameters are iterated and updated by LORPF algorithm to achieve battery RUL prediction with an uncertainty expression of prediction result given. Finally, the method proposed and the traditional PF method are comparatively verified based on the battery data of NASA PCoE in the US and the experimental platform self-built. The results show that the method proposed effectively enhances the RUL prediction accuracy with an error less than 5%. References | Related Articles | Metrics

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Research on Differential Steering by Wire in a Hub-motors-driven Vehicle Wang Qidong, Cao Ye, Chen Wuwei, Zhao Linfeng, Tan Hongliang, Xie Youhao 2019, 41 (12):  1384-1393.  doi: 10.19562/j.chinasae.qcgc.2019.012.006 Abstract ( 296 )   PDF (1793KB) ( 651 )   Save Aiming at the features of the independently controllable and quick and accurate response of torque of each wheel in a hub motor-driven electric vehicle, differential steering is studied. Firstly, a differential steering by wire system is constructed, and through equivalent simplification, the dynamics equation of the system is established. Next, the control system for differential steering by wire is designed. Based on the system model, with the displacement of steering rack as the closed-loop control variable, the control law of nonlinear controller is designed in three steps. The torque distribution scheme is determined to realize the coordinated distribution of torque in each wheel. Then, simulation verifications under classical conditions are carried out. The results show that differential steering by wire can well drive the vehicle to make a turn following driver's intention, the nonlinear controller designed has good control effect, and the involvement of differential steering will affect the steering performance and stability of the vehicle. Finally, based on NI PXI real-time platform and dual-hub-motor test bench, a hardware-in-the-loop test is conducted to verify the effectiveness of the differential steering by wire system constructed. References | Related Articles | Metrics

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Study on Automatic Parking Planning Algorithm Based on Driver's Experience Hu Wen, Tan Yunsheng, Kang Longyun, Yu Zongguang 2019, 41 (12):  1394-1400.  doi: 10.19562/j.chinasae.qcgc.2019.012.007 Abstract ( 437 )   PDF (1087KB) ( 1015 )   Save In order to solve the issues of pivot steering, poor real-time performance and insufficient accuracy in existing vehicle parking algorithms, on the basis of drawing on the experiences of skilled drivers, the mechanism of each stage of vehicle parking process is analyzed with corresponding mathematical models worked out, and a novel automatic parking programming algorithm is designed. The algorithm covers three parts: parking control, steering control and speed control. In parking control, parking path is planned and the desired steering angle and vehicle speed are output. Steering control is for controlling the starting moment of reverse steering, while speed control aims to control the vehicle speed in parking process. Results of simulation show that the algorithm proposed can achieve accurate automatic parking, meeting the requirements of both accuracy and real-time performance in parking control. References | Related Articles | Metrics

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Path Planning for Autonomous Parallel Parking Based on Piecewise Gauss Pseudospectral Method Qian Lijun, Wu Bing, Qiu Duoyang, Hu Weilong 2019, 41 (12):  1401-1409.  doi: 10.19562/j.chinasae.qcgc.2019.012.008 Abstract ( 459 )   PDF (1833KB) ( 575 )   Save A piecewise Gauss pseudospectral method is proposed as a path planning scheme for autonomous parking in different parking spaces in this paper. Firstly, the path planning problem for autonomous parking is transformed into an optimal control problem by establishing a vehicle kinematics model with dynamics constraints, end-point constraints and path obstacle avoidance constraints applied, and the optimal control problem is discretized into a nonlinear problem by Gauss piecewise pseudospectral method in different parking spaces. Then with minimizing total parking time as the objective, an optimization is conducted on nonlinear problem by using interior point method to obtain the optimal parking path. Next, a simulation model is built with Matlab/Simulink, and five autonomous parallel parking conditions with different lengths of parking slot defined, in which the length of parking slot is 1.1-1.8 times of vehicle length. The results of simulation show that the proposed method can uniformly and effectively solve the problem of path planning for autonomous parking, with a shorter parking time and a significantly higher convergence speed in simulation compared with the traditional pseudospectral method. Finally a real vehicle test is also performed to further verify the effectiveness of the method proposed. References | Related Articles | Metrics

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Research on Pedestrian Recognition in Cross-country Environment Based on KDTree and Euclidean Clustering Fan Jingjing, Wang Li, Chu Wenbo, Luo Yugong 2019, 41 (12):  1410-1415.  doi: 10.19562/j.chinasae.qcgc.2019.012.009 Abstract ( 267 )   PDF (1108KB) ( 512 )   Save Pedestrian recognition in cross-country environment is a fundamental requirement of group accompanied automatic driving vehicle. Aiming at the problem of pedestrian recognition in lidar point cloud data, especially under cross-country environment, a clustering-based solution is proposed in this paper. On the basis of theoretical analysis, combined with the geometric and physical features of human being, a pedestrian recognition algorithm based on KDTree and Euclidean clustering is designed and a corresponding test is carried out on tracked vehicle under corss-country environment. The results show that the lidar-based pedestrian recognition algorithm designed can accurately identify the pedestrians in lidar point cloud data, with a good recognition rate in cross-country environment. References | Related Articles | Metrics

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Real-time Pedestrian Detection in Advanced Driver Assistance Systems Based on Improved YOLOv2 Model Bai Zhonghao, Li Zhiqiang, Jiang Binhui, Wang Penghui 2019, 41 (12):  1416-1423.  doi: 10.19562/j.chinasae.qcgc.2019.012.010 Abstract ( 364 )   PDF (2588KB) ( 473 )   Save In order to solve the problem of low detection accuracy of pedestrians with small stature or in complex background in advanced driver assistance systems (ADAS), a real-time pedestrian detection model named YOLOv2-P for ADAS is established based on a deep neural network model YOLOv2. Firstly, the parametric rectified linear unit activation function in feature extraction network is adopted to adaptively learn parameters from training data, and the multi-feature map fusion method is used to fusion low-layer feature map and high-layer feature map in feature extraction network. Next, cross entropy loss function is used instead of sigmoid activation function in model YOLOv2, and the width and height loss functions are normalized. Finally, a clustering is performed on the pedestrian boundary frame size in pedestrian data set by utilizing iterative self-organizing data analysis algorithm. The results of test show that the detection accuracy of the pedestrians with small stature or in complex background with YOLOv2-P model has a significant rise, compare with that with YOLOv2 model, meeting the requirements in accuracy and real-time performance for the pedestrian detection in ADAS. References | Related Articles | Metrics

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Study on Damping Characteristics of Composite Leaf Spring Based on Vehicle Performance Ke Jun, Shi Wenku, Yuan Ke 2019, 41 (12):  1424-1429.  doi: 10.19562/j.chinasae.qcgc.2019.012.011 Abstract ( 292 )   PDF (1293KB) ( 452 )   Save In order to study the damping characteristics of a composite leaf spring,the loss factor test of E-glass fiber/polyurethane laminate plate specimens with typical ply angle is carried out. Based on test results,the loss factor and specific damping in each direction of the laminate plate specimen with 0°ply angle are calculated. Both bench test and vehicle test for the damping performance of composite leaf spring are conducted,with the suitable range of damping parameters of composite leaf spring obtained. The test result of laminated plate is in the same numerical order as that of composite leaf spring assembly, so the test results are credible. Based on test results and related theory, the effects of damping characteristics of composite leaf spring on the handling stability and ride comfort of vehicle are analyzed. The results of vehicle test show that compared with original vehicle, the prototype vehicle equipped with composite leaf spring exhibits the same level of handling stability but an improved ride comfort, being consistent with the results of theoretical analysis. References | Related Articles | Metrics

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Study on the Effects of Pre-compression on Fatigue Performance of Automotive DP590 Steel Plate Wang Qingxia, Wang Guangyao, Zhao Yibing, Fan Peigeng, Zhao Yan 2019, 41 (12):  1430-1434.  doi: 10.19562/j.chinasae.qcgc.2019.012.012 Abstract ( 237 )   PDF (1838KB) ( 499 )   Save In order to analyze the effect of pre-compression on the fatigue performance of steel plate, an experimental study on the fatigue performance and fracture morphology of automotive DP590 steel plates in initial hot rolled state and with 10% pre-compression are conducted respectively. The results show that by applying 10% pre-compression, the fatigue limit of the material increases by 10.6% from 282 to 312 MPa. Meanwhile, the fracture surfaces of specimens in two states are also analyzed, and original region, extended region and instantaneous broken region can be clearly seen. The first fatigue crack appears at the corner of specimen, and there exist a large number of dimples and micro-cracks with different lengths in instantaneous broken region. References | Related Articles | Metrics

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Time-domain Transmission Path Analysis of Vehicle Interior Noise Quality Lu Yuan, Jin Peng, Wang Yulei, Liao Yi 2019, 41 (12):  1435-1441.  doi: 10.19562/j.chinasae.qcgc.2019.012.013 Abstract ( 301 )   PDF (1520KB) ( 470 )   Save The traditional frequency-domain transfer path analysis method is easy to obtain the spectrum characteristics of vibration signals, but it is difficult to combine with the subjective feelings in the vehicle, which leads to low efficiency of analysis and the shortcomings of misjudgement. In order to solve this problem, the correlation between the interior sound quality and the method based on time-domain transfer path analysis is studied. Based on the regression equation of subjective evaluation and objective data of sound quality, the evaluation model of sound quality is established, and the target parameters are set. Then the reliable analysis model of transmission path is obtained by using the method of time-domain transmission path analysis. Finally, through analyzing and calculating the time-domain characteristics of powertrain noise, the in-vehicle contribution of different excitation sources is obtained, and the transmission path is optimized. As a result, the second-order noise pressure level of the engine is reduced by 5 dB(A), and the interior sound quality of the vehicle is improved. References | Related Articles | Metrics

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Application of Volterra Mode of Variational Mode Decomposition and Morphology Fractal Dimension in Engine Fault Diagnosis Zhou Xiaolong, Liu Weina, Jiang Zhenhai, Ma Fenglei 2019, 41 (12):  1442-1449.  doi: 10.19562/j.chinasae.qcgc.2019.012.014 Abstract ( 394 )   PDF (1740KB) ( 289 )   Save A novel engine fault diagnosis method based on volterra mode of variational mode decomposition (VMD) and morphology fractal dimension is proposed to solve the problem of the nonlinearity of the measured engine fault signal and that morphology fractal dimension can not estimate this signal effectively. Firstly, the engine fault signal is decomposed by VMD method, and the noise and false interference components are separated from the signal by the component elimination algorithm of the false intrinsic mode function (IMF) based on mutual information entropy and energy entropy increment. The sensitive IMF components with fault information are reconstructed. Then the Volterra adaptive prediction model is established by reconstructing the phase space of reconstructed signal to obtain the model parameters. Finally, the morphology fractal dimension of the model parameter matrix is calculated and these characteristic parameters are used to identify engine working states and fault types. Through analysis of the measured engine sound vibration signals at different states, the experimental results show that the proposed method can effectively extract the state information characteristics of the engine and realize fault diagnosis for engine abnormal sound signals. References | Related Articles | Metrics

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Research on Fatigue Durability of Automotive Coil Spring Under 2D Random Loading Based on Monte-Carlo Fitting Teng Ruipin, Song Xiaolin, Liu Guoyun, Zeng Junwei 2019, 41 (12):  1450-1458.  doi: 10.19562/j.chinasae.qcgc.2019.012.015 Abstract ( 423 )   PDF (1473KB) ( 357 )   Save A fatigue life calculation method by numerical integration on the probability density function of equivalent load of 2D random load is proposed. The load spectra data of a city SUV on the reinforced pavement in proving ground are collected, and the sample interception method is adopted to conduct parameter estimation and distribution check. The results show that the method can achieve a good fitting of acquired load spectra data in middle and high load section. Meanwhile Monte-Carlo method is applied to generate random series for fitting the probability density function of equivalent load of 2D random load. Finally load spectra grading method and Monte-Carlo probability density function fitting method are used to extrapolate the acquired 2D random loads of four coil springs in suspension, and to calculate their accumulated damage and fatigue life. The results of comparative analysis show that the fatigue life calculation method adopted is feasible, which can well resolve the problem of inability in deriving the probability density function of 2D random load with rather complicated distribution. References | Related Articles | Metrics

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Analysis on Influencing Factors of Whiplash Test Based on Simulation Chen Changliang, Dong Yude, Chen Chao, Li Longqing 2019, 41 (12):  1459-1465.  doi: 10.19562/j.chinasae.qcgc.2019.012.016 Abstract ( 438 )   PDF (2345KB) ( 605 )   Save In order to obtain the law of the influence of some key parameters of car seat on the results of whiplash test, both computer simulation and test are conducted, and the results of simulation are compared with test data. After the feasibility and accuracy of simulation are verified, a few rounds of simulations are carried out. The results show that the smaller the backrest stiffness and the greater the rotational stiffness of backrest, the higher score the whiplash test will get, with the effect of backrest stiffness is more obvious than that of rotational stiffness. The greater the headrest stiffness and the headrest rotational stiffness, the higher score the whiplash test will get, in which the effect of headrest rotation stiffness is more obvious. The higher the headrest and the smaller the headrest back gap, the higher score the whiplash test will get. References | Related Articles | Metrics

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Application of CVDA Sequential Sampling Method to Lightweight Design of Aluminum Alloy Frame Wang Zheyang, Wang Zhenhu, Zhang Songbo, Li Luoxing 2019, 41 (12):  1466-1472.  doi: 10.19562/j.chinasae.qcgc.2019.012.017 Abstract ( 390 )   PDF (2336KB) ( 386 )   Save In lightweight optimization design of aluminum alloy frame, a surrogate model is usually constructed to replace its finite element model for reducing computation effort. For further enhance computation efficiency so as to establish a high-accuracy surrogate model with lesser sample points, an improved sequential sampling method named CVDA is proposed and compared with three existing sampling methods (OLHD, MDA and CVA) through a calculation sample. The results show that the prediction accuracy of surrogate model built with CVDA sampling is 11.1%, 11.1% and 30.3% higher than that with OLHD, MDA and CVA sampling methods respectively with a R2 value reaching 0.95. Then the CVDA method is applied to building the surrogate model of aluminum alloy frame in bending and torsion conditions, and with the same number of sample points, the prediction accuracy of surrogate model built with CVDA method is apparently higher than that with other sampling method. On this basis, a lightweight optimization is conducted on aluminum alloy frame, and as a result, the bending stiffness, torsional stiffness, 1st order bending modal frequency and 1st order torsional modal frequency increase by 2.54%, 3.38%, 0.68% and 2.75% respectively, and the mass reduces by 7.47 kg with a mass reduction rate of 7.20%, showing an obvious optimization result. References | Related Articles | Metrics