Table of Content

25 August 2021, Volume 43 Issue 8 Previous Issue    Next Issue

Select

Research on Dynamic Characteristics of Electric Drive System Under Regenerative Braking Condition Kun Liu,Changhong Du,Wei Wu,Guocheng Lu,Shihua Yuan 2021, 43 (8):  1121-1127.  doi: 10.19562/j.chinasae.qcgc.2021.08.001 Abstract ( 543 )   HTML ( 31 )   PDF (1945KB) ( 443 )   Save In order to study the dynamic characteristics of electric vehicle drive system in the regenerative braking process， the tire torsion characteristics are further coupled on the basis of considering static transmission error， backlash and time?varying meshing stiffness and the electromechanical coupling model of permanent magnet synchronous motor?two stage transmission mechanism?tire is established and verified by experiments. The influence of tire torsional characteristics and regenerative braking torque on the dynamics of the electric drive system is analyzed. The results show that the tire torsional characteristics introduce a new mode into the electric drive system， which changes the first?order mode of the system. Gear continuous impact events of the transmission mechanism occur when the regenerative braking torque is small， and with the increase of regenerative braking torque， the impact events gradually disappear， but the dynamic load of the transmission mechanism increases when the electromagnetic torque is reversed. The research provides theoretical support for dynamic load study and life prediction of the electric drive system. Figures and Tables | References | Related Articles | Metrics

Select

Analysis and Optimization Design of IPMSM with a Double⁃layer Permanent Magnet Structure of Electric Vehicles Xiping Liu,Jiesheng Fu,Longxin Du,Gaosheng Zhu Wenjian Guo 2021, 43 (8):  1128-1135.  doi: 10.19562/j.chinasae.qcgc.2021.08.002 Abstract ( 334 )   HTML ( 12 )   PDF (1987KB) ( 278 )   Save In order to accurately and quickly obtain the air?gap flux density waveform， the equivalent magnetic circuit method is used to analyze and calculate the air?gap magnetic field of the inter permanent magnet synchronous machine （IPMSM） with a double?layer permanent magnet structure. Considering the influence of the stator slotting effect， the air?gap length is corrected by the improved Carter coefficient. To reduce waveform total harmonics distortions （THD） of air?gap magnetic flux density and torque ripple， a Taguchi method is introduced for multi?objective fast optimization design analysis for the motor cores. The multivariable and multi?objective optimization design process of IPMSM with a double?layer permanent magnet structure is described using finite element simulation analysis and numerical calculation. The analysis shows that the output torque of the optimized double?layer IPMSM is improved by 2%， the torque ripple is reduced by 2.77%， the no?load air?gap magnetic density harmonic distortion rate is reduced by 4.28%. The experiments of the prototype have verified the reliability of the finite element and the validity of the theoretical analysis. Figures and Tables | References | Related Articles | Metrics

Select

Influences of Series and Parallel Permanent Magnet on Electromagnetic Force of Common Rail High⁃speed Solenoid Valve Peng Liu,Jiafu Deng,Liyun Fan,Gang Wu,Lin Hu 2021, 43 (8):  1136-1142.  doi: 10.19562/j.chinasae.qcgc.2021.08.003 Abstract ( 143 )   HTML ( 6 )   PDF (2832KB) ( 200 )   Save The performance of high?speed solenoid valve directly affects the characteristics of fuel injection system in high pressure common rail diesel engine. In order to reveal the hybrid excitation mechanism of series and parallel permanent magnet with electromagnetism for the novel high?speed solenoid valve， the effects of series and parallel permanent magnet on the electromagnetic force of the system are analyzed by numerical simulation. Firstly， the simulation model of novel high?speed solenoid valve is established by using ANSYS Maxwell software with its accuracy verified. Then， a simulation is conducted to analyze the effects of series and parallel permanent magnet rings and their interaction on the electromagnetic force of high?speed solenoid valve in full working condition. The results show that the electromagnetic force is positively correlated with the height of parallel permanent magnet ring， and is negatively correlated with the height of series permanent magnet ring. With the increase of driving current， the interaction between the height of series permanent magnet ring and the height of parallel permanent magnet ring gradually weakens. Figures and Tables | References | Related Articles | Metrics

Select

Influence of Pilot Injection Strategy Coupled with EGR on the Working Process of DN Dual Fuel Engine Guisheng Chen,Feng Wei,Renxin Xiao,Jingxian Zhang,Zhenjiang Zhang Han Wang 2021, 43 (8):  1143-1151.  doi: 10.19562/j.chinasae.qcgc.2021.08.004 Abstract ( 158 )   HTML ( 5 )   PDF (5284KB) ( 221 )   Save The influence of different pilot?injection strategies coupled with EGR on the combustion and emission characteristics of diesel/natural gas （DN） dual fuel engine are studied based on the three?dimensional fluid dynamics software. The results show that when the pilot diesel injection ratio （FDIR） is fixed and the pilot diesel injection timing （FDIT） is advanced beyond -10（°）CA ATDC， the burning center of gravity （CA 50） is closer to the top dead center. It is beneficial to reduce CH4， HC， CO and Soot emissions. But the NOx emission is higher than that of single injection and reaches the peak when the FDIT is advanced to -20（°）CA ATDC. When FDIT is advanced to -10（°）CA ATDC， the increase of FDIR has little influence on emission. When FDIT is advanced beyond -10（°）CA ATDC， larger FDIR can keep CH4， HC， CO and Soot emissions at a low level. As the EGR rate increases， the emissions of CH4， HC， CO， and Soot of different pilot?injection strategies are generally increased. When the EGR rate reaches 15%， the FDIT is advanced to -20（°）CA ATDC， and the FDIR is 30%， the emission value of each gas is generally lower than that of the single injection. When the EGR rate reaches 25%， the NOx emission of different pilot?injection strategies is reduced to the lowest level while the CO and Soot emissions exceed that of the single injection. Figures and Tables | References | Related Articles | Metrics

Select

Analysis on the Key Influencing Factors of Distributed Current Measurement in PEMFC Xudong Liu,Xuezhe Tao Jianjian Wei 2021, 43 (8):  1152-1160.  doi: 10.19562/j.chinasae.qcgc.2021.08.005 Abstract ( 224 )   HTML ( 15 )   PDF (1478KB) ( 368 )   Save Vehicle?mounted PEMFCs have obvious current density inconsistencies in a large effective area. Distributed measurement is a common method to study current density distribution. In order to study the key influencing factors of measurement accuracy， models of PCBs and cell components are established in COMSOL to perform finite element numerical simulation. The results show that the assembly pressure in the range of 0.5-3.0 MPa has little influence. Measurement accuracy is greatly reduced when resistance value of the resistance increases from 1 mΩ to 100 mΩ while resistance installation method and the number of segments have limited influence. The conductivities in x and y directions of the bipolar plate have more significant impact and the temperature drift has little influence. Therefore， to improve the measurement accuracy， there is no need to optimize the temperature drift and change the optimal assembly pressure. Resistor with small resistance should be used， choosing resistor installation method and the number of segments according to the needs and bipolar plate with smaller conductivity in x and y directions and larger conductivity in z direction should be selected. Figures and Tables | References | Related Articles | Metrics

Select

Study on Thermal Runaway Propagation Process of Battery Module Based on Phase Change Materials Na Yang,Yixin Tong,Lijun Zhao,Jianfeng Wang 2021, 43 (8):  1161-1167.  doi: 10.19562/j.chinasae.qcgc.2021.08.006 Abstract ( 190 )   HTML ( 4 )   PDF (2423KB) ( 369 )   Save For studying the heat transfer path in the process of battery thermal runaway propagation， a thermal runaway model for battery module is established and verified by needle punching experiments， which consists of a one?dimensional electrochemical model， an internal short circuit model， a three?dimensional heat transfer model and a side reaction model and coupled with each other. A thermal management scheme for battery module based on phase change materials and liquid cooling is proposed to analyze its suppression role to the thermal runaway propagation of battery module. The results show that the thermal management scheme proposed can extend the time interval of thermal runaway of each battery in a battery module and speed up the temperature decline of each battery， playing a good role in suppressing the thermal runaway propagation of battery module. Figures and Tables | References | Related Articles | Metrics

Select

Identification Method for Occupant Personalized Ride Comfort of Autonomous Vehicles Fengchong Lan,Shicheng Li,Jiqing Chen,Zongmao Shen 2021, 43 (8):  1168-1176.  doi: 10.19562/j.chinasae.qcgc.2021.08.007 Abstract ( 310 )   HTML ( 17 )   PDF (1820KB) ( 482 )   Save For the problem that autonomous vehicle trajectory planning control algorithm cannot meet the personalized comfort of occupants， combining natural driving data and occupant comfort requirements， a method for identifying occupants’ personalized comfort is established. Firstly， the subjective comfort evaluation method is determined. Based on the standard ISO2631， frequency domain and time domain weighted filter functions are built. Subjective and objective characteristic parameters of occupant comfort of autonomous vehicles are extracted and the relationship between occupant’s personalized comfort and autonomous vehicle driving planning parameters is identified. Then， a natural driving data acquisition platform is established to collect the driving parameters and subjective and objective parameters that affect comfort. Factor analysis is used to reduce the dimensions of driving parameters to obtain three?way motion （lateral impact， longitudinal acceleration， and vertical vibration）， driving risk and efficiency influencing factors. Finally， the weighted analysis method is used to identify the model， and the Kalman filter algorithm is applied to quickly and accurately identify the individual needs of the occupant， and the weighted root?mean?square threshold of comfort is obtained. The identification results show that the correlation between the subjective and objective comfort of the occupant reaches 85.81%； the three?way motion factor has a greater impact on the occupant comfort than the driving risk and efficiency factors； the identification rate of occupant personalized comfort is as high as 93%. The study can provide theoretical support for constructing personalized trajectory planning control algorithm considering occupant comfort. Figures and Tables | References | Related Articles | Metrics

Select

Cooperative Adaptive Cruise Control of Intelligent Vehicles Based on DMPC Ruoyu Lu,Jie Hu,Ruinan Chen,Wencai Xu,Kai Cao 2021, 43 (8):  1177-1186.  doi: 10.19562/j.chinasae.qcgc.2021.08.008 Abstract ( 382 )   HTML ( 19 )   PDF (3211KB) ( 370 )   Save Aiming at the cooperative adaptive cruise control （CACC） problem of nonlinear vehicle platoon with unidirectional communication topology， a distributed model predictive control （DMPC） strategy is proposed in this paper， which ensures the stability of platoon and meets the requirements of vehicle following performance， safety and occupant comfort of each vehicle in the platoon. Firstly， the dynamic model and communication topology structure model of vehicle platoon are established， the cost function and system constraints are designed based on the multiple optimal performance of the platoon system， an open?looped local optimization problem is solved for each following vehicle in the platoon based on the limited information it receives， and the optimal control quantity at the current moment is calculated as the input. This process is repeated constantly to fulfill the goal of rolling optimization， achieving the CACC of the vehicle platoon. Then， the Lyapunov candidate function is constructed by the sum of local cost functions of CACC system， and the sufficient conditions for the asymptotic stability of vehicle platoon system are proved. Finally， a Carsim/Simulink joint simulation is conducted to analyze the control performance of the algorithm for vehicle platoon with different forms of one?way communication topology in ideal state， followed by a real vehicle test to verify the control performance of the algorithm in a real vehicle conditions of the jitter in perception layer and delay and error in the bottom control layer. Simulation and real vehicle test results show that the control strategy proposed can enable the vehicle platoon fulfill its optimized performances with better robustness to external disturbances. Figures and Tables | References | Related Articles | Metrics

Select

A Dynamic Model Predictive Control Approach for Multipoint Preview Path Tracking of Articulated Vehicles Sixu Li,Biao Xu,Manjiang Hu,Yougang Bian,Xiaolong Sun Ning Chen 2021, 43 (8):  1187-1194.  doi: 10.19562/j.chinasae.qcgc.2021.08.009 Abstract ( 315 )   HTML ( 32 )   PDF (1814KB) ( 522 )   Save The existing path tracking control methods have large errors in the process of model linearization and preview， which leads to reduction of tracking accuracy. For path tracking control of articulated vehicles， a dynamic model of articulated vehicles is established.The model is linearized based on state trajectories so that the linearization error can be compensated， and the control target considering path multipoint preview errors is proposed. The model predictive controller based on the dynamic model is constructed to optimize the steering torque at the hinge point. To verify the effectiveness of the method， the joint simulation platform by Matlab/Simulink and Adams software is built for control verification by conducting simulation experiments. The results show that the controller designed can effectively improve path tracking accuracy for articulated vehicles. Figures and Tables | References | Related Articles | Metrics

Select

A Method of Vehicle Detection at Night Based on RetinaNet and Optimized Loss Functions Bingli Zhang,Haoran Qin,Shang Jiang,Jieyu Zheng,Zhenghai Wu 2021, 43 (8):  1195-1202.  doi: 10.19562/j.chinasae.qcgc.2021.08.010 Abstract ( 317 )   HTML ( 26 )   PDF (1243KB) ( 357 )   Save In view of the high false detection rate and poor detection results for distant small target in vehicle detection at night for intelligent driving system， the loss functions are comprehensively optimized based on RetinaNet. For classification loss function， both the generation mechanism and the influence on training results of the IoUs of negative and positive samples are analyzed， the classification loss function of correlated IoU is constructed， the IoU of negative sample is used to make network lay emphasis on the training of negative samples， which are hard to classify， meanwhile the IoU of positive sample is used to enhance the locating accuracy of detection frame. For locating loss function， the normalization way of traditional L1 loss is improved and the ability of small target detection is enhanced. In addition， a design optimization is conducted on network structure for the vehicle features in night scene， and a test verification is performed on vehicle data at night. The results show that the average detection accuracy of the model optimized increases by 14.6 percentage point. Figures and Tables | References | Related Articles | Metrics

Select

Study on Driving Behavior Detection Method Based on Improved Long and Short⁃term Memory Network Dongmei Shi,Feng Xiao 2021, 43 (8):  1203-1209.  doi: 10.19562/j.chinasae.qcgc.2021.08.011 Abstract ( 227 )   HTML ( 11 )   PDF (2430KB) ( 335 )   Save Fatigue driving and unsafe driving behavior are the main causes of traffic accidents. With the progress of intelligent transportation technology， using deep learning algorithm to detect driving behavior has become one of the hotspots of research. On the basis of convolution neural network （CNN） and long?term memory neural network， a hybrid dual stream convolution neural network algorithm is proposed by combining attention mechanism to improve network structure. In spatial flow channel， CNN is used to extract the spatial feature values of video image and the traditional mean pooling is replaced by spatial pyramid pooling is used to replace mean pooling， with the transformation of feature map unified. In time stream channel， single shot detection algorithm is adopted to calculate two adjacent frames of optical flow images of video sequence for detecting small facial targets such as human eyes. Then the fusion and classification of image features are carried out. Finally， experiments are performed on LFW dataset and self?built dataset. The results show that with the method adopted the accuracy of face recognition and fatigue driving detection is 1.36 and 2.5 percentage points higher than other methods respectively. Figures and Tables | References | Related Articles | Metrics

Select

A Simulation Investigation of Eye Injury Risk of Vehicle Occupant Shaopeng Li,Shucai Xu,Shuang Chen,Binbing Huang,Jiwei Yin 2021, 43 (8):  1210-1215.  doi: 10.19562/j.chinasae.qcgc.2021.08.012 Abstract ( 147 )   HTML ( 11 )   PDF (1415KB) ( 180 )   Save Based on the anthropometric parameters of Chinese 50th percentile adult male， a head model of Chinese physical sign safety dummy with biomechanical response of eye tissue is developed. The acceleration response of the head model in the drop calibration test is verified in LS?DYNA software， and the influence of airbag on eye tissue damage under frontal impact condition is explored. The damage risk curve of normalized energy and damage probability of eye tissue is established by using the simulation data. The results show that in the head drop simulation test， the head acceleration response of the Chinese physical sign crash dummy is higher than that of the Hybrid III dummy； in the frontal crash condition， the simulation test results of the occupant restraint system show that when the crash speed is higher than 55 km/h， the risk of retinal detachment will increase， and the von Mises stress and deformation of sclera will reach the threshold of eyeball rupture. Figures and Tables | References | Related Articles | Metrics

Select

Comparative Study on the Injury of Different Percentile Dummies in Vehicle Oblique Crash Yongqiang Wu,Aifa Lou Lei Zhang 2021, 43 (8):  1216-1222.  doi: 10.19562/j.chinasae.qcgc.2021.08.013 Abstract ( 343 )   HTML ( 3 )   PDF (3573KB) ( 236 )   Save Oblique crash is one of the most common types of traffic accidents. However，there are only few researches and related regulations available on oblique crash and their protection object is mainly the 50th dummy， without paying due attention to 5th and 95th dummies. In order to improve the relevant standards on vehicle safety and further reduce the casualties in oblique crash accidents， a test platform for 18° oblique crash is built， three test methods are established， and data of 69 tests for 15 vehicle models are compared to analyze the injuries of different parts of the 5th， 50th and 95th dummies. The results show that the neck， pelvis and right thigh of the 50th dummy have the highest risk of injury， the head and chest injury indicators of the 5th dummy are 12.2% and 34.1% higher than that of the 50th dummy respectively， while the left thigh force of the 95th dummy is 456.8% higher than that of the 50th dummy， indicating that all drivers with different statures shall suffer injury to different degrees in 18°oblique crash. This study provides the most powerful data and technical supports for further improvement of related vehicle safety standards and also has guiding significance for vehicle enterprises in optimizing vehicle design. Figures and Tables | References | Related Articles | Metrics

Select

Study on the Injury of THOR Dummy in Vehicle MPDB Test Ming Liu,Bo Shang,Qingjiang Zhao 2021, 43 (8):  1223-1227.  doi: 10.19562/j.chinasae.qcgc.2021.08.014 Abstract ( 300 )   HTML ( 9 )   PDF (1705KB) ( 200 )   Save A vehicle MPDB （mobile progressive deformable barrier） test is conducted to study the relationship between crash severity and vehicle mass， the injury features of dummy and the influence of crash severity and seatbelt force limit on the injury of THOR dummy. The results show that the crash severity is negatively correlated with vehicle mass， while the injury of THOR dummy is positively correlated with the crash severity. The thorax of THOR dummy is the part with highest risk of injury， and the level of seatbelt force limit is the key factor affecting chest compression. Finally， the level of seatbelt force limit required for reducing the chest compression of THOR dummy is calculated based on test data analysis. Figures and Tables | References | Related Articles | Metrics

Select

Intrinsic Parameters Modeling for LiDAR and Point Cloud Correction Method Xiaolong Zhang,Kun Jiang,Kai Sun,Maolin Liu,Zhenlei Shao,Pengchuan Xiao,Diange Yang 2021, 43 (8):  1228-1237.  doi: 10.19562/j.chinasae.qcgc.2021.08.015 Abstract ( 302 )   HTML ( 17 )   PDF (4649KB) ( 382 )   Save In this paper， an intrinsic parameter model with less parameters and dedicated to mechanical LiDAR is established， and in view of the effects of eccentric structure on point cloud， two point?cloud correction methods （angle and distance corrections） are proposed. A simulation is conducted on the effects of two correction methods， with its results verified by real point cloud. Finally， a pose estimation algorithm is also used to validate the effectiveness of the correction methods proposed. Figures and Tables | References | Related Articles | Metrics

Select

Study on Crosswind Stability of Van Truck on Sea⁃crossing Bridge Zhiqun Yuan,Lü Hengqing,Li Lin,Xiaobo Lin,Xiujing Gao 2021, 43 (8):  1238-1247.  doi: 10.19562/j.chinasae.qcgc.2021.08.016 Abstract ( 141 )   HTML ( 5 )   PDF (8374KB) ( 193 )   Save An aerodynamics and system dynamics-based unidirectional coupling numerical model for a van truck on the sea-crossing bridge is established and verified by wind tunnel test. Then a simulation is conducted to study the high-speed aerodynamic stability of a truck on the bridge under the action of step gust and comparatively analyze the wind-resistance performance of the wind barrier with different types and structural parameters and its effects on the aerodynamic stability of vehicle. Finally， a quantified evaluation method for the wind-induced diving safety and the wind resistance design of bridges is put forward. Figures and Tables | References | Related Articles | Metrics

Select

Flow Field Simulation of Engine Compartment in a Commercial Vehicle and Design Optimization of Flow Guiding Shroud Yan Shi,Yao Li,Peipei Xu 2021, 43 (8):  1248-1253.  doi: 10.19562/j.chinasae.qcgc.2021.08.017 Abstract ( 211 )   HTML ( 10 )   PDF (3360KB) ( 266 )   Save In order to enhance the heat dissipation capacity of a commercial vehicle in maximum torque condition， the flow field characteristics and cooling performance of engine compartment are studied by using CFD technology. Though the comparison between the simulation results and wind tunnel test data， the mesh size and the reliability of model are verified. To tackle the reflux phenomenon of hot air occurring at the upper part and both sides of the radiator， a flow guiding shroud is added on the base of original fan guard， with its structural parameters optimized by using CFD technology combined with the design of experiments. The simulation results show that the inverse flow of hot air is greatly reduced after the flow guiding shroud is added， with a minor rise of the flow rate of cooling air. Finally a validation road test for thermal balance is performed with a result indicating that with the low guiding shroud added， the allowable extreme ambient temperature is raised by 3.4 ℃， verifying the effectiveness of flow guiding shroud added. Figures and Tables | References | Related Articles | Metrics

Select

Optimization of Eddy Current Loss of the New Cooling System of Axial Flux Motors Jiujian Chang,Chen Wang,Xinxin Zheng,Jianping Fang,Xiaolin Wang,Peng Kang 2021, 43 (8):  1254-1262.  doi: 10.19562/j.chinasae.qcgc.2021.08.018 Abstract ( 175 )   HTML ( 8 )   PDF (4463KB) ( 243 )   Save The internal cooling system of stator yokeless axial flux motor has eddy current loss， which leads to the reduction of motor efficiency and temperature increase. In this paper， a cooling system of a stator yokeless axial flux motor is modeled with a vehicle hub motor as the research object. Through simulating and analyzing the eddy current loss of the cooling system during the operation of the motor， and performing two?dimensional finite element equivalence of the motor， the mechanism of eddy current loss of fins is further investigated. Based on this， the eddy current loss is optimized from three different perspectives， namely， optimizing the stator tooth shape to reduce the magnetic field strength at the fins， optimizing the fin height through magneto?thermal coupling analysis， and slotting the fins to increase the eddy current path resistance， which finally reduces the eddy current loss to 32.7% of the original one. The experimental tests of the prototype are carried out. The results show that the finite element simulation and experimental test results are consistent and the efficiency of the optimized motor is improved at different speeds， with the efficiency of the optimized motor 3.1% higher than that of the unoptimized motor at 4 000 r/min. Figures and Tables | References | Related Articles | Metrics

Select

Subjective⁃Objective Test and Correlation Analysis of Automobile Seat Vibration Comfort Liangsong Chen,Jun Song,Yi Qiu,Zunming Wang 2021, 43 (8):  1263-1269.  doi: 10.19562/j.chinasae.qcgc.2021.08.019 Abstract ( 358 )   HTML ( 18 )   PDF (2271KB) ( 495 )   Save The vibration characteristic of automobile seat directly affects the ride comfort. In order to comprehensively evaluate the vibration comfort of the seat， the correlation between the objective comfort of the seat and the subjective comfort of the occupant is studied and analyzed in this paper. Firstly， the automobile seat is tested under different excitation amplitudes in the vertical direction. The transmission of vibration from the floor to the human body interface is measured to characterize the dynamic performance of the Seat-occupant Coupling System （SoCS）. Then， the relative amplitude estimation method is designed for subjective evaluation， and the subjective-objective correlation analysis is carried out. Finally， a parameter characterizing the vibration isolation performance of the seat is proposed. The results indicate that： （1） The resonance frequency of SoCS becomes lower when the vibration magnitude increases. In addition， the vertical in line FRF and cross axis FRF have strong correlation at the first resonance frequency； （2） The correlation between the subjective evaluation and the objective test is pretty good （the fitting accuracy is 99.05%）， which verifies the effectiveness of the amplitude estimation method； （3） The proposed seat vibration isolation performance parameter is in good agreement with the subjective evaluation， which can provide a theoretical basis for the optimization and improvement of the vibration comfort of the automobile seat. Figures and Tables | References | Related Articles | Metrics