Table of Content

03 July 2019, Volume 41 Issue 6 Previous Issue    Next Issue

Select

A Study on Finite Element Analysis and Structural AssessmentMethod for Aluminum-alloy Vehicle Body Wang Wanlin, Xu Congchang, Wang Zhenhu, Wang Zheyang, Li Luoxing 2019, 41 (6):  607-614.  doi: 10.19562/j.chinasae.qcgc.2019.06.001 Abstract ( 633 )   PDF (3949KB) ( 611 )   Save In order to explore the design method of lightweight aluminum-alloy vehicle body, the finite element analysis method and the overall evaluation method of aluminum-alloy body structure are emphatically discussed with an aluminum underbody as an example in this paper. Firstly, the shell element is used to simulate the welds of aluminum-alloy, a finite element model for vehicle body is built, and a simulation on its basic performance is conducted with a result showing that compared with the results of bending / torsional stiffness tests and modal test, the relative error of bending stiffness, torsional stiffness, 1st-order bending mode and 1st-order torsional mode are -2.45%, -3.59%, -3.43% and -2.73% respectively, verifying the correctness of the FE model for aluminum-alloy vehicle body. Then a concept of generalized structure stiffness is introduced for evaluating the force transfer performance of vehicle body, and by identifying the force transfer path of vehicle body the weak regions of vehicle body structure are located and a structural modification is performed. After optimization, the bending stiffness, torsional stiffness, 1st-order bending mode and 1st-order torsional mode of vehicle body increase by 5.59%, 1.99%, 2.42% and 0.65% respectively, while the body mass has a slight rise (0.19kg), demonstrating the effectiveness of the overall structure assessment method of vehicle body based on generalized structure stiffness. References | Related Articles | Metrics

Select

Multi-Fuzzy Control Based Energy Management Strategy ofBattery/Super-capacitor Hybrid Energy System of Electric Vehicles Yao Dizhao, Xie Changjun, Zeng Tian, Huang Liang 2019, 41 (6):  615-624.  doi: 10.19562/j.chinasae.qcgc.2019.06.002 Abstract ( 348 )   PDF (5226KB) ( 470 )   Save The energy management strategy of multi fuzzy control is proposed and designed, in order to overcome the shortcomings of the single fuzzy control strategy for electric vehicle with lithium battery-super-capacitor hybrid energy system. According to the actual parameters of the test bench, the vehicle model is built under the MATLAB environment. Through the comparison and analysis of the pulse modulation fuzzy control strategy, power allocation factor fuzzy control strategy and modified fuzzy control strategy based on pulse modulation under the ECE and UDDS driving cycle, the optimal modified fuzzy control strategy based on pulse modulation is embedded into the experimental bench for verification. The experimental results show that the control strategy proposed in this paper can achieve smooth control of the charging and discharging current of lithium batteries within 1C under different SOC conditions, which is conducive to the safe operation of the lithium battery and can effectively reduce driving cost of the vehicle. References | Related Articles | Metrics

Select

Energy Management Strategy Optimization of Hybrid Energy StorageSystem Based on Radau Pseudo-spectral Method Liu Yanwei, Zhu Yunxue, Lin Ziyue, Zhao Kegang, Ye Jie 2019, 41 (6):  625-633.  doi: 10.19562/j.chinasae.qcgc.2019.06.003 Abstract ( 617 )   PDF (781KB) ( 391 )   Save This paper proposes an energy management strategy optimization method based on Radau pseudo-spectral method (RPM). The global interpolation polynomial is used to approximate the state variables and control variables in the system. The derivative of the interpolation polynomial approximates the differential equation of the state variables in the dynamic equation. Then the optimal control problem (OCP) is transformed into a nonlinear programming problem (NLP) problem of the variable to be optimized. Taking the battery life model with penalty factor as the objective function, the battery life (the number of battery cycles) in the hybrid energy storage system (HESS) electric vehicle is compared with that with the single battery energy source under the NEDC cycle condition. The results show that the pseudo-spectral optimized HESS can reduce the Ah throughput of the battery pack and reduce the current and power fluctuation range. The battery power and ultracapacitor power have a segmented linear relationship with the required power, and the equivalent life of the battery in the HESS is 25.61% higher than that of the single battery energy source. This paper provides a fast and stable optimization method for the energy management strategy of the HESS, which lays a foundation for matching the optimal system parameters and can be used as an evaluation benchmark for other optimization strategies. References | Related Articles | Metrics

Select

Effect of EGR Exhaust Gas Composition and Temperature onMechanical Characteristics of Diesel Engine Particles Zhao Yang, Li Mingdi, Wang Zhihao, Xu Guangju, Yuan Yinnan, Wu Bin 2019, 41 (6):  634-640.  doi: 10.19562/j.chinasae.qcgc.2019.06.004 Abstract ( 289 )   PDF (2990KB) ( 576 )   Save Focusing on micro-mechanical properties of diesel engine particles, the variation of particle size, number and mass concentration were studied by using particle size analyzer and atomic force microscope for different EGR exhaust gas composition and temperature. The effect of EGR exhaust gas composition and temperature on the micro-mechanical properties such as particle elastic modulus, agglomeration forces and main action forms were analyzed. The results show that the total number concentration of nucleation mode particles has little change with the exhaust gas temperature increasing, however the total number concentration of accumulation mode particles increases significantly, and the particle elastic modulus, structure rigidity and agglomeration forces all increase significantly, while the force action type changes from liquid bridge force to Van Der Waals force. Compared with the introduction of exhaust gas, when N2 and CO2 are introduced respectively, the agglomeration force between particles is mainly in the form of Van Der Waals force and liquid bridge force. The N2 in exhaust gas is the main gas composition that leads to the increase of particle size, number concentration and mass concentration, structural rigidity and agglomeration force of accumulation mode particles with EGR introduced while the CO2 can significantly reduce the number and mass concentration of accumulated particles and reduce the structural rigidity and agglomeration force. References | Related Articles | Metrics

Select

A Research on Hybrid Energy Storage System for Battery Electric Mining Trucks Zhang Wei, Yang Jue, Zhang Wenming, Ma Fei 2019, 41 (6):  641-646.  doi: 10.19562/j.chinasae.qcgc.2019.06.005 Abstract ( 163 )   PDF (1144KB) ( 375 )   Save Aiming at the efficiency lowering of the battery in electric mining truck due to the impact of repeating charging and discharging with high power and large current,a life prediction model for a large-capacity lithium-iron phosphate battery in a 55 t battery electric mining truck is established. In a condition of meeting the power performance and energy requirements of vehicle, with enhancing vehicle fuel economy and battery service life as objectives, a parameter matching on battery-ultracapacitor hybrid energy storage system is conducted. With the rule-based hybrid energy control strategy, a simulation is performed on Matlab/Simulink platform by using ADVISOR2002. The results show that the hybrid energy storage system can effectively improve the energy efficiency of battery electric mining truck, extend the service life of battery and enhance the fuel economy and power performance of battery electric mining truck. References | Related Articles | Metrics

Select

A Study on the Influences of Grounding CharacteristicParameters on the Grip Performance of Tire Wang Guolin, Chen Xingpeng, Zhou Haichao 2019, 41 (6):  647-653.  doi: 10.19562/j.chinasae.qcgc.2019.06.006 Abstract ( 284 )   PDF (1110KB) ( 626 )   Save In order to evaluate the tire grip performance on both dry and wet roads from the angle of tire grounding characteristics, ten 205/55R16 tires from different manufacturers are studied. The overall footprint of tire is divided into three parts: shoulder region; transition region and central region, and tire grounding test is conducted to get the parameters of its grounding characteristics. Then a correlation analysis is performed to single out the high correlated grounding parameters and the quantitative relationships between grounding parameters and tire grip performance on both dry and wet grounds are revealed by using principal component analysis. The results show that good fitting results are achieved of the regression equations for the grip performance of tire on both dry and wet grounds characterized by tire grounding parameters, and the outcome of the research can play a good guiding role in the structural design of high-performance tires. References | Related Articles | Metrics

Select

A Research on Cooperative Path Tracking and Anti-roll Control ofCommercial Vehicle Based on Pareto Optimal Equilibrium Theory Li Yushan, Chi Yuanxin, Ji Xuewu, Liu Yulong, Wu Jian 2019, 41 (6):  654-661.  doi: 10.19562/j.chinasae.qcgc.2019.06.007 Abstract ( 155 )   PDF (1031KB) ( 371 )   Save In view of the coupling problem between lateral control and anti-roll control in path tracking of commercial vehicle, the lateral control and anti-roll control systems are regarded as participants in dynamic game process, and a cooperative lateral and anti-roll control strategy is proposed based on Pareto optimal equilibrium theory. Firstly, a yaw-roll coupling model of commercial vehicle is established, and is then augmented into an Intelligent vehicle-road closed loop model by using vehicle lateral position, heading angle and road preview information. Next, separate lateral and anti-roll controllers are designed based on the theory of linear quadric regulator for comparison. On the basis of separate optimal controllers and with further consideration of the control interaction between game participants, a cooperative lateral and anti-roll control strategy based on Pareto optimal equilibrium theory is devised. Finally, the simulation verification of slalom test with two control strategies are conducted and the results show that compared with separate optimal controllers, the proposed cooperative controller based on Pareto optimal equilibrium theory can effectively enhance the accuracy of path tracking while assuring better rolling and handling stabilities. References | Related Articles | Metrics

Select

A Research on Steering Wheel Resistance Torque of aCommercial Vehicle Based on LuGre Model Zhu Xianmin, Song Jian, Cheng Shuai 2019, 41 (6):  662-667.  doi: 10.19562/j.chinasae.qcgc.2019.06.008 Abstract ( 235 )   PDF (1038KB) ( 493 )   Save To study the resistance torque of the steering wheel of a commercial vehicle, the LuGre model is introduced into the steering dynamics analysis of a commercial vehicle, and the model for aligning torque and steering friction resistance torque of tire and the resistance torque model of steering wheel are established. With these models the relationship among steering resistance torque, steering angle and vehicle speed of a CA1045 light truck is analyzed. The comparison between the results of simulation and real vehicle test shows that their difference in steering resistance torque is less than 5 N·m. References | Related Articles | Metrics

Select

A Study on Vehicle Lateral Tracking Control Based on Arc-length Preview Li Shuang, Xu Yanhai, Chen Jing, Zhu Pengxin 2019, 41 (6):  668-675.  doi: 10.19562/j.chinasae.qcgc.2019.06.009 Abstract ( 492 )   PDF (1484KB) ( 751 )   Save In order to improve the computational efficiency and adaptability of path control algorithm based on preview theory,in this paper, an arc-length preview method is proposed to obtain the lateral displacement of preview point based on actual driving distance of the car on the basis of the preview optimal curvature model. With this method, the relationship between the lateral displacement of preview point and the rotation angle of front wheel is deduced . Then the lateral control model of path tracking is established through the derivation of lateral tracking closed-loop control system block diagram. Finally, in the CarSim/Simulink co-simulation environment, the effectiveness of the model and the factors which affect the steering wheel stability of the human-vehicle-road closed-loop system under this method are simulated and analyzed by establishing several typical simulation conditions. The results show that the method has the advantages of high tracking accuracy, fast calculation speed and good adaptability in lateral path tracking control. Furthermore, the steering wheel tends to be stabilized when the closed loop system satisfieds both the conditions that the direction of desired path points has continuity and the preview distance is greater than the critical forward distance. References | Related Articles | Metrics

Select

Performance Measurement and Analysis of the Active NoiseControl System for Mass Production Vehicle Liu Feng, Wu Ming, Yang Jun 2019, 41 (6):  676-681.  doi: 10.19562/j.chinasae.qcgc.2019.06.010 Abstract ( 284 )   PDF (2092KB) ( 455 )   Save Vehicle interior noise control is one of the most important research areas in vehicle noise, vibration and harshness (NVH). Conventional passive noise control technology is very effective for medium and high frequency noise (higher than 500 Hz), but ineffective for low frequency noise. Active noise control (ANC), base on destructive interference, is suitable for controlling low frequency noise and has been adopted as standard configuration by the whole series of many mass production vehicle models. So far researchers in academia concentrate on developing new algorithms and optimizing their performance mainly while the report on the effect of active noise control in industry is one-sided and there is little detailed measurement results published on ANC system installed in mass production vehicle. In order to provide reference for academic research and more detailed information about the actual effect of active noise control system to car makers, the performance and robustness of the ANC system installed in a commercial vehicle are tested when the car is stationary and running, respectively. Experiment results show that the ANC system has good control of the engine noise and good robustness. References | Related Articles | Metrics

Select

A Research on the Evaluation Method of High-frequencyWhining Noise in Electric Drivetrain Kang Qiang, Gu Pengyun, Li Jie, Zuo Shuguang 2019, 41 (6):  682-687.  doi: 10.19562/j.chinasae.qcgc.2019.06.011 Abstract ( 966 )   PDF (2810KB) ( 1426 )   Save Compared with the low-frequency ignition, mechanical and combustion noises in internal combustion engine, the main noise of the drivetrain of electric vehicle becomes higher-frequency whine caused by electromagnetic force and gear meshing, making people agitated. Since there is no such masking of the operating noise as in internal combustion engine, these high-frequency monotonic noises can be significant in electric drivetrain in some operating conditions. But battery electric vehicles still have noises caused by road, tire and wind, so it is necessary to consider both the sound pressure level of monotonic noise and the masking effect of other noises. The sound pressure level, TNR and subjective scores of the interior noise of seven battery electric vehicles are compared with a result showing that TNR is consistent with subjective perception in trend, while the sound pressure level cannot be directly used to evaluate the significance of whining noise. Based on the TNR distribution of the main orders of electric drive assembly, the range of TNR value corresponding to the whining significance of electric vehicle is obtained. Finally, the NVH target setting method and suggestions for the electric drive assembly is summarized. References | Related Articles | Metrics

Select

A Research on Drag Reduction Effect of AerodynamicDrag Reducing Device for Van Truck Xu Jianmin, Fan Jianming 2019, 41 (6):  688-695.  doi: 10.19562/j.chinasae.qcgc.2019.06.012 Abstract ( 310 )   PDF (3742KB) ( 342 )   Save In order to reduce the aerodynamic drag coefficient of a van type truck, different types of bionic cab spoiler, tail fairing and bionic non-smooth surface structure are designed. Then their effects on the aerodynamic drag coefficient of the truck are analyzed, with their drag reduction mechanism discussed in detail. Finally, the overall drag reduction effect is studied with different drag reduction devices installed on the same truck model. The results show that the drag reduction effect of bionic cab spoiler is better than that of traditional one, and with the increase of the extension length of cab spoiler‘s side skirt, the drag coefficient of the truck gradually reduces. When the inclination angle of the lower deflector of tail fairing is around 45°, the drag coefficient of the model gets a minimum value. Based on the bionic drag reduction theory for biological surface, both semi-spherical pits and semi-ellipsoidal pits arranged on the side of the truck have good drag reduction effect. The combination of three types of drag reducing devices on truck model can get a drag reduction rate of up to 22.7%. References | Related Articles | Metrics

Select

Safety Assessment of Child Occupant Exposure to Electromagnetic Field Generated by DC Power Cable in Battery Electric Vehicles Dong Xuwei, Lu Mai 2019, 41 (6):  696-702.  doi: 10.19562/j.chinasae.qcgc.2019.06.013 Abstract ( 395 )   PDF (2095KB) ( 284 )   Save To assess the level of child occupant exposure to electromagnetic field generated by DC power cables in battery electric vehicles, the models for passenger compartment, child body and DC power cables are established with finite element software Comsol Multiphysics, based on basic principle of electromagnetic dosimetry. A simulation on the models is conducted to analyze the magnetic flux density in different tissues of child body sitting on the different positions of compartment, which are then compared with the guidelines of International Commission on Non-Ionizing Radiation Protection (ICNIRP). The results show that in general low speed drive with a cable current of 27 A, the maximum magnetic flux density in child body tissues at different sitting position is: 0.18 μT (front passenger seat), 0.182 μT (left back seat), 1.26 μT (middle back seat), and 17.8 μT (right back seat) respectively, while in high-speed cruise drive with a cable current of 150 A, the corresponding maximum magnetic flux densities are around 5.5 times as high as that at low-speed drive. However, these levels are still far below the limit values recommended by ICNIRP, indicating that the magnetic flux density generated in passenger compartment by DC power cable will not cause health risk to child occupant. References | Related Articles | Metrics

Select

A Study on Steady-state Performance of Winding Type Permanent Magnet Coupler in W-ECHPS System of a Heavy Vehicle Xia Lei, Jiang Haobin, Geng Guoqing 2019, 41 (6):  703-710.  doi: 10.19562/j.chinasae.qcgc.2019.06.014 Abstract ( 357 )   PDF (2799KB) ( 466 )   Save To solve the problems of poor steering feeling and high energy consumption in the hydraulic power steering system of a heavy vehicle, a winding type permanent magnet coupler (WTPMC)-based electronically controlled hydraulic power steering (W-ECHPS) system is proposed in this paper. The structural principles of W-ECHPS and WTPMC are introduced, the operating parameters of WTPMC under different driving conditions are determined to provide the basis for its design and performance study based on driving condition. Finite element simulations on WTPMC using Ansoft Maxwell software are conducted to study its steady-state performances, including electromagnetic, speed-regulating and slip power recovery performances. On the basis of simulation results meeting requirements, WTPMC prototype is manufactured and bench tests are carried out with their results compared with simulation ones in respects of line back-EMF in no-load condition, duty ratio of IGBT and terminal voltage of ultracapacitor. The results show that the outcomes of simulation basically agree with test data, WTPMC has good electromagnetic performance, can meet the requirement of operating limits, and can operate in different driving conditions by regulating the duty ratio of IGBT. In addition, it has good slip power recovery performance, with a slip power recovery rate between 67.4% and 72.5%. References | Related Articles | Metrics

Select

Dimensional Stability Analysis of Polylactic-acid StructuralParts Based on Time Hardening Theory Ma Fangwu, Han Lu, Chen Shixian, Pu Yongfeng, Shen Liang 2019, 41 (6):  711-716.  doi: 10.19562/j.chinasae.qcgc.2019.06.015 Abstract ( 168 )   PDF (3025KB) ( 395 )   Save The battery tray of polylactic acid in an electric vehicle is designed based on equal stiffness theory. Through topology optimization the maximum stress and displacement of battery tray reduce by 26.5% and 19.7% respectively while its mass drops by 8.5%. With consideration of the creep characteristics of nonmetallic materials, the creep model of the material is established based on the theory of time hardening, and a finite element analysis is conducted to get the creep strain of battery tray under long-term loading condition. The results show that polylactic acid parts meet the design requirements of product in terms of dimension stability, verifying the feasibility of the application of polylactic acid to automotive products. References | Related Articles | Metrics

Select

Multi-objective Optimization on Structure Layout of Sliding Door Keeper Zhou Qiaoying, Xue Zhigang, Zhou Wufeng, Lin Qiquan, Li Luoxing 2019, 41 (6):  717-722.  doi: 10.19562/j.chinasae.qcgc.2019.06.016 Abstract ( 295 )   PDF (2564KB) ( 489 )   Save A simulation analysis on the sliding door keeper of a benchmarking car is conducted with software LSDYNA, and the verification test is performed in accordance with the requirements of GB15086—2013. Then the parametric design of middle guide, hook and rear lock structural layouts are carried out, and the approximate model for the separation distance between the door and frame is built based on optimum Latin hypercube sampling method and RBF neural network model. Finally, a multi-objective optimization for the distances of middle guide, hook and rear lock along vertical direction is completed by using NSGA-II algorithm. The results show that the maximum upper and lower separation distances between sliding door and its frame is 65.42 and 65.99 mm respectively, and the guide wheel does not fall off from guide rail, with the total displacements of both B and C column side loading plates are less than 300 mm, meeting the performance requirements of door keeper according to the national standard. References | Related Articles | Metrics

Select

An Analysis on Thermal Comfort in Passenger CompartmentBased on Human Thermal Regulation Model Chen Jiqing, Zheng Xijiao, Lan Fengchong, Peng Rui 2019, 41 (6):  723-730.  doi: 10.19562/j.chinasae.qcgc.2019.06.017 Abstract ( 264 )   PDF (3370KB) ( 681 )   Save For studying the dynamic thermal reaction rule of occupants so as to enhance the thermal comfort in passenger compartment, with concurrent consideration of environmental parameters, body regulation, metabolism, clothing thermal resistance and other factors, a calculation method of coupling the interior thermal environment with human-body thermal regulation model is established, and the dynamic variations of average skin temperature of head, chest, arms and legs are calculated, with the heat regulation reaction and thermal comfort changing rule analyzed. The results show that the coupling calculation method can reliably analyze the dynamic thermal response and thermal comfort of occupants. When heating system is switched on, the interior thermal environment transiently changes and the skin temperature on different parts of occupant in different seating positions changes differently. In heat environment, the thermal regulation parameters of human-body, i.e. vasodilation and sweating increase, and hence heat is taken away from the body to maintain body temperature constant. References | Related Articles | Metrics