Table of Content

25 July 2018, Volume 40 Issue 7 Previous Issue    Next Issue

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Optimization on Power Distribution Strategy for a Dualmotor Integrated Battery Electric Bus Xie Shaobo, Liu Tong, Li Huiling & Wei Lang 2018, 40 (7):  749.  doi: 10.19562/j.chinasae.qcgc.2018.07.001 Abstract ( 247 )   Save The operation mode of a dualmotor integrated battery electric vehicle is optimized with minimizing its energy consumption as objective. A simulation using China city bus cycle is conducted with four power distribution strategies, i.e. optimizationbased dynamic programming (DP) strategy and instantaneous consumption minimization strategy (ICMS), and rulebased symmetric torque (ST) distribution strategy and mainauxiliary (MA) motor torque distribution strategy respectively. The results of simulation indicate that for dualmotor integrated battery electric vehicle, DP, as a global optimization strategy, tends to be degenerated into ICMS, meaning that ICMS should be the best scheme of operation mode distribution for dualmotor integrated battery electric vehicle, and the electricity consumption per 100km with DP/ICMS strategy is 507 and 229kW·h less than that with ST and MA strategy respectively. Related Articles | Metrics

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A Research on Optimal Curve Fuzzy Control Strategy for ExtendedRange Electric Vehicles Niu Jigao, Niu Dantong, Xu Chunhua & Pei Fenglai 2018, 40 (7):  757.  doi: 10.19562/j.chinasae.qcgc.2018.07.002 Abstract ( 235 )   Save In view of the energy assignment of multipower sources and the randomness and uncertainty of real vehicle driving conditions in an extendedrange electric vehicle, an optimal curve fuzzy control strategy is put forward. The strategy includes two fuzzy subcontrollers to perform the fuzzy adjustment of engine operation region and the fuzzy assignment of series power, for deciding the working interval on the optimal curve of engine and the output power assignment between engine/generator and traction battery respectively in series powertrain configuration. The results of offline HIL simulation indicate that the control strategy adopted has a high generality and good robustness and can achieve the preset control objectives with a better fuel economy. Related Articles | Metrics

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Real Time Prediction for Remaining Mileage of Battery Electric Vehicle Based on Modified PSORBF Algorithm Chen Dehai, Ren Yongchang, Huang Yanguo & Hua Ming 2018, 40 (7):  764.  doi: 10.19562/j.chinasae.qcgc.2018.07.003 Abstract ( 265 )   Save To solve the problems of the large error, poor adaptability and complex modeling in predicting the remaining mileage of battery electric vehicles, firstly, the combined parameters for the clustering algorithm of particle swarm optimization (PSO) are selected. Then, the clustering for the number of hidden layer nodes q, the center vector ci and standardization constant δi of Gauss function in hidden nodes is conducted with PSO, the best combined parameters with least error and best clustering results are determined and timely updated according to different conditions for achieving the dynamic adaptability of prediction results. The modified PSORBF prediction model is established with terminal voltage, current, temperature and load as inputs and remaining mileage as output, the dynamic adaptive standard battery capacity and standard driving mileage in the fix and common environment of vehicle operation are defined, and the mathematical model for nonessential energy consumption is set up to correct the modified PSORBF prediction model. Finally, the results of comparison between test values and predicted values by different algorithms for EV1 battery electric vehicle show that the maximum relative error with RBF, PSORBF and modified PSORBF algorithms is 99%,62% and 38% respectively, demonstrating the significant enhancement in the accuracy of remaining mileage prediction by modified PSORBF, compared with other algorithms. Related Articles | Metrics

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A Research on Driving State Estimation for Distributed Drive Electric Vehicle Based on NAEKF Geng Guoqing, Wei Binyuan, Jiang Haobin, Hua Yiding & Wu Zhen 2018, 40 (7):  770.  doi: 10.19562/j.chinasae.qcgc.2018.07.004 Abstract ( 240 )   Save It is greatly important to accurately estimate the driving state for the longitudinal and lateral stability control of a distributed drive electric vehicle (DDEV). Noise adaptive extended kalman filtering (NAEKF) algorithm is adopted to estimate the driving state of DDEV in this paper. The algorithm makes full use of the realtime statistical information of observed signal. By monitoring the dynamic change of innovations and residuals of filter, the state noise variance and measurement noise variance are constantly corrected, with filter gain and the proportions of predicted and observed state values in state values filtered adjusted, hence improving state estimation accuracy. Finally the algorithm adopted is verified by simulation with vehicle dynamics software veDYNA. Results show that compared with EKF, the algorithm adopted can effectively overcome the problem of inaccuracy in prior statistical information and the inaccuracy in estimation caused by complex conditions, with a mean error of state estimation not more than 27%, a root mean square error not more than 26%, and a rather small peak relative error. Related Articles | Metrics

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Effects of Fuel Injection Timing and Exhaust Gas Recirculation on Combustion and Emissions of Diesel /MF Blends Xiao Helin, Wang Ru, Zeng Pengfei & Hou Beibei 2018, 40 (7):  777.  doi: 10.19562/j.chinasae.qcgc.2018.07.005 Abstract ( 161 )   Save An experimental study is conducted on the combustion and emission characteristics of a compression ignition engine fueled with 2methylfuran (MF) and its blend with diesel fuel. The results show that incylinder pressure peak lowers when injection timing is close to top dead center (TDC) and the adoption of exhaust gas recirculation (EGR) can obviously reduce incylinder pressure peak and heat release rate. The advance of injection reduces CO emission while the retard of injection and the adoption of EGR can apparently lower NOx emission, and the use of MFdiesel blend fuel can significantly reduce soot emission. Under the same injection timing, the effects of EGR on larger particulates are more significant than that on small ones. The effects of EGR on the number concentration of particulates become larger when injection timing is closer to TDC, and under the effects of EGR, the number of large particulates increases and the mass concentration of particulates rises accordingly when injection timing is earlier than 125°CA BTDC. Related Articles | Metrics

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A Research on Crashworthiness of a Minivan Based on Platform Rolling Liu Changye, Mo Yimin, Wei Yong, Liang Yongbin & Xu Donghui 2018, 40 (7):  783.  doi: 10.19562/j.chinasae.qcgc.2018.07.006 Abstract ( 226 )   Save A finite element simulation model for the tumbling test of a minivan is established, with its reliability verified by the benchmarking on motion attitude, motion parameters and component deformation. According to the test and simulation results of deformation, force and energy absorption of the vehicle, two cross beams of roof and left and right Apillars are determined to be the key structures of target vehicle in rolling collision process. Based on the crashworthiness and energy absorption characteristics of vehicle body, with concurrent considerations of evaluation indicators, i.e. survival space intrusion and structural energy absorption, key structure optimization is completed by using Opt LHD design of experiment, Kriging approximate models, NAGAII multiobjective optimization and proportional coefficient optimization algorithms. After optimization, the total mass of key structures reduces by 2478%, the total energy absorbed by structures lowers by 1881% while the average specific energy absorption for key components increases by 1189%. Related Articles | Metrics

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Crashworthiness and Lightweight Design of Mule-car Body Based on Multi-objective Reliability Optimization Lü Xiaojiang, Zhou Dayong, Sun Guangyong, Liu Weiguo & Gu Xianguang 2018, 40 (7):  790.  doi: 10.19562/j.chinasae.qcgc.2018.07.007 Abstract ( 277 )   Save With a frontal 40% overlap deformable barrier crash as example, a multiobjective reliability optimization on the structure parameters of car body is conducted by using technologies of the design of experiment, RBF metamodel and multiobjective reliability analysis. The results show that after optimization, the structure of car body meets the requirements of crashworthiness and lightweighting, with the reliability of structure enhanced, providing an effective reference for the design of car body structure. Related Articles | Metrics

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Analysis and Optimization on Time-varying Stability of Automotive Disc Brake Wang Hanbei, Yu Dejie & Huang Ya 2018, 40 (7):  795.  doi: 10.19562/j.chinasae.qcgc.2018.07.008 Abstract ( 210 )   Save To tackle the problem of reliability decline and braking noise caused by the wear of disc brake, an analysis / optimization method for the timevarying stability of vehicle disc brake system is proposed. With the method, the random process parameters are introduced to describe the brake structure with wear during operation. A parametric model covering random parameters and random process parameters for the brake system with uncertainty is constructed to perform the dynamic prediction of stable reliability during brake operation. On this basis and aiming at the reliability decline in the later stage of brake operation, an optimization on the timevarying stability of brake system is conducted by using the analysis theory for timevarying reliability, response surface technique and genetic algorithm, with minimizing the negative complex eigenvalue of damping ratio as objective, to ensure its reliability meeting requirements in the later stage of operation. Finally the method is effectively applied to the prediction on the timevarying reliability of a brake with floating caliper as an example, with its stable reliability in the later period of operation effectively enhanced by an optimization on the density and thickness of supporting back plate of the brake. Related Articles | Metrics

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An Experimental Study on Anti-lock Braking of Continuous Regenerative Braking System in Electric Vehicles Liu Zhiqiang & Pu Xian 2018, 40 (7):  804.  doi: 10.19562/j.chinasae.qcgc.2018.07.009 Abstract ( 228 )   Save Electric vehicles use conventional friction braking and the regenerative braking of drive motor to achieve antilock braking. In this paper, the advantages and disadvantages of antilock braking system (ABS) are analyzed, and an antilock control system based on PI control is proposed and then verified by real vehicle test. Three different structural configurations for ABS are designed: hydraulic ABS alone, regenerative ABS in front axle only and hydraulic and regenerative ABS in front axle and hydraulic ABS in rear axle, with their braking performances evaluated. Hydraulic ABS is based on rule controllers, while continuous regenerative ABS controls slip ratio through target gain, proportional integral and feedforward/feedback controllers. The results of test on lowadhesion road show that regenerative ABS can accurately track the ideal curve of wheel slip ratio in braking process, reduce the frequency of vehicle body vibration and improve the ride comfort of vehicles. Related Articles | Metrics

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A Study on Dynamic Characteristics of Differential Steering in Distributed-drive Wheeled Vehicles Xu Tao, Shen Yanhua, Zhang Wenming & Xie Jincheng 2018, 40 (7):  812.  doi: 10.19562/j.chinasae.qcgc.2018.07.010 Abstract ( 222 )   Save Aiming at the problem that the current theory on the differential steering in wheeled vehicles does not take into consideration of tire twist characteristics and the dynamic characteristics of steadystate differential steering, a study on the dynamic characteristics of differential steering in wheeled vehicles is conducted based on the twist and cornering characteristics of tire. The models for both singleand dualaxle distributed drive wheeled vehicles are set up to analyze the mechanism of the interaction between tire and road and the forming process of steadystate differential steering, and the effects of aligning torque, cornering force, which are caused by the twist and transverse deformation of tire, lateral force and the structural dimension of vehicle on steadystate differential steering are discussed. The results show that the hysteresis of tire twist and the aligning torque it produces have great effects on the steadystate differential steering of vehicle. The process of differential steering of dualaxle wheeled vehicles is a coupling action of cornering and sideslip and the essential condition for differential steering is that wheel track must be larger than wheel base. Related Articles | Metrics

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Finite Element Analysis and Test of the Transmission Error of Hypoid Gear in Drive Axle Liu Guozheng, Shi Wenku, Chen Zhiyong, Yang Changhai & Zhang Xiangcun 2018, 40 (7):  820.  doi: 10.19562/j.chinasae.qcgc.2018.07.011 Abstract ( 230 )   Save Based on the finite element model of drive axle assembly, the transmission error of hypoid gear is analyzed by simulation, and a test rig is also built to measure the transmission error of hypoid gear under different working conditions. The results of simulation show that the curve of hypoid gear transmission error moves down as the loading torque increases, while the amplitude of the transmission error reduces first and then increases. At light load, the amplitude of the transmission error curve decreases as the loading torque rises due to the deformation compensation of hypoid gear. But when the loading torque further increases to an extent that the transmission error curve is below the lowest end of the designed transmission error curve, the tooth edge contact of gears happens, making the amplitude of transmission error become larger. The results of test exhibit the same law as those of simulation do. Related Articles | Metrics

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Simulation on Occupant Surface Temperature Distribution and Thermal Comfort in Passenger Compartment Zhou Sheng & Fu Haiming 2018, 40 (7):  826.  doi: 10.19562/j.chinasae.qcgc.2018.07.012 Abstract ( 230 )   Save The simulation on the temperature distribution of human body surface is very important to the evaluation of mobile air conditioner comfort. In order to simplify the boundary conditions for human body simulation for analyzing the thermal comfort of passenger compartment, the human body is regarded as an internal homogeneous heat source. Based on the physiological heat transfer equation of human body, a numerical simulation on the surface temperature distribution of human body in car and thermal environment of passenger compartment is conducted. By using RNG kε turbulence model and SIMPLE algorithm, with consideration of the effects of solar radiation and the radiation between human body and the environment on the temperature and airflow velocity distributions of human body and passenger compartment, the influences of second and third category boundary conditions on the simulation on the temperature distribution of human body are analyzed. In addition, UDF is compiled to simulate the distributions of temperature, airflow velocity, PMV/PPD and draft sensation of human body and compartment. The results show that the simulation results of body surface temperature distribution agree well with the test results in literature, in which the simulation results with third category boundary conditions are closer to the test results than that with second category boundary conditions. With the second category boundary conditions, the correctness of the simulation results mainly depends on the selection of heat flux density, while with the third category boundary conditions, simulation is more convenient, and the airflow velocity, human body temperature, PMV/PPD and draft sensation in passenger compartment are well distributed. Related Articles | Metrics

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An Experimental Study on Engine Heat Balance and Its Influencing Factors Yong Anjiao, Fu Yonghong, Zhang Linbo & Guo Jianfeng 2018, 40 (7):  834.  doi: 10.19562/j.chinasae.qcgc.2018.07.013 Abstract ( 263 )   Save In view of the vital importance of the accuracy of heat balance test to the selection and matching of vehicle cooling system, a measure is proposed to increase the difference between outlet temperatures and inlet temperature for reducing test error based on an analysis on the error mechanism of heat balance test, and a modification design of existing test bench is conducted with good results achieved. On this basis, the effects of key factors such as different coolant temperatures, different inlet air temperatures and with or without test fan etc. on the results of heat balance test are also studied. Related Articles | Metrics

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Misfire Fault Diagnosis of Diesel Engine Based on Wavelet and Deep Belief Network Jia Jide, Jia Xiangyu, Mei Jianmin, Zeng Ruili & Zhang Shuai 2018, 40 (7):  838.  doi: 10.19562/j.chinasae.qcgc.2018.07.014 Abstract ( 361 )   Save In order to deeply understand the mechanism of misfire fault of diesel engine and increase the correct rate of misfire fault diagnosis, a misfire fault diagnosis method of diesel engine is proposed based on wavelet and deep belief network (DBN) in this paper. Firstly, equalangle sampling method is used to sample the cylinder head vibration signals of diesel engine, with smooth angulardomain signals obtained and the disturbance of cyclic fluctuation eliminated. Then, by means of continuous wavelet transform, an angularfrequency analysis is conducted on angulardomain signals, which are then reconstructed after the frequency band near ignition frequency is extracted. Next, in accordance with the working cycle of diesel engine, 12 commonlyused feature parameters such as variance, kurtosis and peak value and so on are extracted section by section from reconstructed signals with the diagnostic parameter matrix constructed. Finally, by using DBN, the dimension of the diagnostic parameter matrix is reduced and the features are extracted second time, based on which misfire faults are diagnosed. The method is applied to a diesel engine, with a result showing that the method can accurately extract fire failure information and effectively diagnose misfire faults. Related Articles | Metrics

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A Method of Engine State Evaluation Based on Improved Kmeans Algorithm Gu Guangyu, Liu Jianmin & Qiao Xinyong 2018, 40 (7):  844.  doi: 10.19562/j.chinasae.qcgc.2018.07.015 Abstract ( 191 )   Save In view of the present difficulty in engine state evaluation under the condition of prior knowledge absence, an evaluation method of engine state based on improved Kmeans clustering algorithm is proposed in this paper. This method uses Kmeans algorithm to avoid the influence of subjective factors during evaluation. Correlation indicators are put forward, the algorithm is modified, and the corresponding weights are given according to the properties of feature parameters. A selection method of initial clustering centers with minimum variance heuristic algorithm is used to avoid the interference of acnodes and noise points during initial clustering center selection in the condition of small sample size, and Bootstrap small sample statistical method is adopted to weaken the effects of the randomness of test samples on evaluation model. Finally, the feasibility and validity of the method are verified by real example evaluation, indicating that compared with the traditional method, this method is more objective and stable. Related Articles | Metrics

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Analytic Calculation and Analysis of Magnetic Field in Surfacemounted Permanent Magnet Motor Zhang Heshan, Deng Zhaoxiang, Yang Jinge, Tuo Jiying & Zhang Yu 2018, 40 (7):  850.  doi: 10.19562/j.chinasae.qcgc.2018.07.016 Abstract ( 427 )   Save A global analytic model for the electromagnetic field of surfacemounted permanent magnet motor is established by using Fourier series method and the noload and load electromagnetic characteristics of the motor are analyzed. In 2D polar coordinate system, the solution domain of the motor is divided into five subdomains: permanent magnet, air gap, armature slot, stator slot opening and auxiliary slot. The Laplace equation or Poisson equation for each subdomain is solved with variable separation method, and the harmonic coefficients in the general solution are determined according to boundary conditions, with the analytic expressions of each subdomain obtained. The electromagnetic parameters including the magnetic density in air gap, noload back EMF, cogging torque and electromagnetic torque are calculated, and the correctness of analytic method is verified by finite element analysis. On this basis, the influences of polar arc coefficient, auxiliary slot size and slot opening width on cogging torque and electromagnetic torque are studied. In addition, an analytic model for unequal slot openings matching is proposed to reduce cogging torque peak and electromagnetic torque ripple. The method can reflect the relationship between the designed motor performance and its size and parameters and can be used in the initial design and optimization of the motor. Related Articles | Metrics

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Driving Intention Recognition Based on HMM and SVM Cascade Algorithm Liu Zhiqiang, Wu Xuegang, Ni Jie & Zhang Teng 2018, 40 (7):  858.  doi: 10.19562/j.chinasae.qcgc.2018.07.017 Abstract ( 291 )   Save In order to reduce the false alarm rate of the advanced driver assistance system, a method for identifying driving intention is proposed by using the difference of “drivervehicleroad” parameters under different tasks. Experiments are carried out in driving simulator system, 1150 driving samples of 12 testees are recorded, and a driving intention recognition indicator system with 6 parameters are determined by comparing the sample difference of different driving intentions: lane keeping, lane change and overtaking. Using HMM and SVM cascade algorithm to establish driving intention recognition model. The results show that the correct recognition rate of driving intentions based on the algorithm reaches 9584%, obviously higher than that using HMM or SVM model alone, with an average single recognition time of 0017s, meeting the requirements of reaction time of driver to emergency events. Related Articles | Metrics

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Effects of Surface Treatment on Bonding Performance of 5182 Aluminum Alloy Used in Vehicle Body Joints Chen Shuochen, Li Guangyao & Cui Junjia 2018, 40 (7):  865.  doi: 10.19562/j.chinasae.qcgc.2018.07.018 Abstract ( 195 )   Save In this paper, adhesive bond technique is employed to achieve the bonding of 5182 aluminum alloy used in vehicle body, different surface treatments are adopted to change the surface quality of panel, and the effects of surface parameters such as surface roughness and microscopic surface area on the morphology of joint interface and mechanical properties are studied. The wettability, mechanical properties and the features of fracture surface are analyzed by means of surface free energy measurement, tension / sheer tests and optical microscope measurement. The results show that emery cloth scraping can increase the surface roughness and bonding area of aluminum alloy panels, strengthen the mechanical seizing effects between adhesive and panel, and enhance joint bonding strength. Among them, scraping by P360 can get a greatest enhancement in joint bonding strength, and higher or lower roughness will cause a reduction in effective contact area between adhesive and panel, leading to the lowering of the bonding strength of joints. Related Articles | Metrics