Table of Content

25 January 2022, Volume 44 Issue 1 Previous Issue    Next Issue

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Performance Analysis of Hydrogen Recirculation System of High Power Fuel Cell Vehicles Jiquan Han,Xiangcheng Kong,Jianmei Feng,Xueyuan Peng 2022, 44 (1):  1-7.  doi: 10.19562/j.chinasae.qcgc.2022.01.001 Abstract ( 354 )   HTML ( 205 )   PDF (2787KB) ( 366 )   Save High power hydrogen fuel cell commercial vehicles is the focus to promote the application of hydrogen energy and the design of an efficient hydrogen recirculation system is crucial for the performance of fuel cell vehicles. In this paper， four hydrogen recirculation schemes are analyzed for a 200 kW high power fuel cell vehicle system. The performance evaluation index of the hydrogen recirculation device is established， and the characteristics of each hydrogen recirculation scheme are analyzed from different aspects based on theoretical analysis and CFD simulation. The results show that the power consumption of the hydrogen pump can be reduced significantly with the combination of the ejector and hydrogen pump. Compared with the hydrogen pump mode， the maximum power of the hydrogen pump in parallel mode is reduced by 81.4%， and the maximum power in series mode is reduced by 85.3%. The analysis of the contribution rate and power consumption of hydrogen recirculation shows that the series mode of ejector and the hydrogen pump can make better use of the performance of ejector. Figures and Tables | References | Related Articles | Metrics

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Longitudinal Cruise Control of Intelligent Vehicles Based on Adaptive Dynamic Sliding Mode Control Jian Zhao,Jinpeng Du,Bing Zhu,Zhiwei Wang,Zhicheng Chen,Xiaowen Tao 2022, 44 (1):  8-16.  doi: 10.19562/j.chinasae.qcgc.2022.01.002 Abstract ( 378 )   HTML ( 187 )   PDF (2704KB) ( 618 )   Save To eliminate the effects of parameter uncertainty and external disturbances on the longitudinal cruise control of intelligent vehicles， a longitudinal cruise control method based on adaptive dynamic sliding mode is proposed. The vehicle longitudinal dynamics model is established with the derivative term of generalized longitudinal force as control input， and a novel sliding mode function is constructed based on the backsteping method to ensure that the vehicle speed and longitudinal acceleration converge to the desired value at the same time. On this basis， the dynamic sliding mode control law of the desired generalized longitudinal force is designed and the unknown disturbances in the control law are compensated adaptively by using RBF neural network. The actuator selection module is designed to convert the desired generalized longitudinal force into the desired control input in actuator layer， with the comparative simulation and real vehicle test conducted. The results show that the longitudinal cruise control method proposed for intelligent vehicles can effectively eliminate the influences of parameter uncertainty and external disturbance， improve the chattering of traditional sliding mode control， and achieve the stable and accurate tracking of the desired cruise speed. Figures and Tables | References | Related Articles | Metrics

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Path Tracking Control of Intelligent Vehicles Based on Fuzzy LQR Jie Hu,Xinkai Zhong,Ruinan Chen,Linglei Zhu,Wencai Xu,Minchao Zhang 2022, 44 (1):  17-25.  doi: 10.19562/j.chinasae.qcgc.2022.01.003 Abstract ( 474 )   HTML ( 194 )   PDF (3090KB) ( 454 )   Save In order to ensure the accuracy and stability of the path tracking of intelligent vehicles under different speeds, a fuzzy linear quadratic regulator (LQR) with rotation angle compensation using preview PID for path tracking control is designed in this paper. Firstly, the LQR controller is designed based on the path tracking error model, and the preview PID algorithm is used to compensate the rotation angle，eliminate the steady-state error and enhance the tracking accuracy. Then, aiming at the problem of poor adaptability to different speeds of the controller with fixed weighting factors, a speed-based fuzzy adjustment strategy of weighting factors is proposed. Finally, a real vehicle test is conducted to verify the control performance of the controller in real world environment. The results show that the controller designed has high tracking accuracy, and can maintain good accuracy and stability under different vehicle speeds. Figures and Tables | References | Related Articles | Metrics

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Semantic Segmentation Method of On-board Lidar Point Cloud Based on Sparse Convolutional Neural Network Xiangteng Xia,Dafang Wang,Jiang Cao,Gang Zhao,Jingming Zhang 2022, 44 (1):  26-35.  doi: 10.19562/j.chinasae.qcgc.2022.01.004 Abstract ( 190 )   HTML ( 18 )   PDF (3725KB) ( 300 )   Save The semantic segmentation of point cloud obtained by on-board lidar scanning is one of the important means for ensuring driving safety and enhancing the driver's understanding of surrounding environment. Due to memory limitation and the sparse characteristics of large-scale point cloud scenes， directly continue to apply the traditional neural network approach to the large-scale point cloud scenario does not work well. Therefore， taking the advantage of the sparseness of large-scale point cloud， sparse convolutional neural network （sparse CNN） is used to extract the characteristics of voxel cloud in this paper. With consideration of the information loss cause by density inconsistence in point-wise processing sub-branch suppressed point cloud data， additional 3D-CA and 3D-SA modules are designed to improve the characteristics extraction of sparse CNN. The results of experiment show that compared with traditional convolutional neural network method and point cloud projection on plane method， the sparse CNN method for the semantic segmentation of large scale point cloud can have 4.1% and 3.4% higher IOU respectively， demonstrating the effectiveness of the method adopted. Figures and Tables | References | Related Articles | Metrics

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Research on Ergonomic Evaluation of Driver-based Intelligent Cabin Shucong Yu,Jian Meng,Bin Hao 2022, 44 (1):  36-43.  doi: 10.19562/j.chinasae.qcgc.2022.01.005 Abstract ( 351 )   HTML ( 31 )   PDF (1862KB) ( 438 )   Save For the interactive experience of intelligent cabin of car driving， this paper studies and proposes a test and evaluation method for smart cabin. The function points of the cabin are divided according to the vehicle scenarios， and subjective indicators， vehicle indicators， eye movement indicators and other multi-dimensional index systems according to the function points are combined to build a comprehensive evaluation model of cabin interactive experience based on the combination of subject and objective evaluation methods. Then the analytic hierarchy process is used to determine the weight of the index by level. Finally， a driver-based smart cabin ergonomic evaluation model is established. Validation through cabin interaction cases proves that this model can quantitatively evaluate the comprehensive scores of cabin function points in various vehicle scenarios， which can provide a theoretical basis for the optimization and research and development of the intelligent cabin interactive experience for driving. Figures and Tables | References | Related Articles | Metrics

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Micro-Structure and Oxidation Characteristics of Particulate Matter of Typical Biodiesel Combustion Changkai Jia,Dengpan Zhang,Genrui Zhao,Li Su,Deqing Mei,Yinnan Yuan 2022, 44 (1):  44-51.  doi: 10.19562/j.chinasae.qcgc.2022.01.006 Abstract ( 243 )   HTML ( 5 )   PDF (3112KB) ( 168 )   Save The micro-structure and oxidation characteristics of combustion particulates in high pressure common rail diesel engine are analyzed for three types of biodiesel with different iodine values， respectively soybean oil methyl ester （SME）， palm oil methyl ester （PME） and waste cooking oil methyl ester （WME）， by using the EEPS particle size spectrometer， high-resolution transmission electron microscope and synchronous thermal analyzer. The results show that compared with diesel combustion particulate matter （PM）， biodiesel PM has smaller particle size， higher aggregation degree and more disordered microcrystalline carbon layer， and lower initiation temperature （Ti）， burnout temperature （Te） and peak temperature of maximum weight loss rate （Tp） . The box dimensions of PM of SME， PME and WME are 0.8%， 0.9% and 1.1% larger than that of diesel PM. Besides， compared with diesel PM， the average particle size decreases by 5.1%， 6.7%， 13.9% and the apparent activation energy decreases by 12.4%、13.4% and 16.9% respectively and the energy required for oxidation reaction decreases. With the decrease of iodine value of biodiesel， the quantity concentration of biodiesel combustion PM decreases， the box dimension increases， the internal carbon layer of PM becomes shorter and curved， and the oxidation activity increases. Figures and Tables | References | Related Articles | Metrics

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Effect of Air Flow Conditions in Cylinder and Double-Point Ignition on Flame Propagation Characteristics and Thermal Efficiency of CNG Engine Miao Yang,Xuedong Lin,Degang Li,Yingshu Liu 2022, 44 (1):  52-57.  doi: 10.19562/j.chinasae.qcgc.2022.01.007 Abstract ( 213 )   HTML ( 4 )   PDF (2633KB) ( 139 )   Save Improving the indicative thermal efficiency of CNG-DI engine is an important way to meet the requirements of low carbonization. In this paper， CFD software AVL FIRE is used to simulate and analyze the combustion process and in-cylinder flow field characteristics of CNG-DI engine modified with 2.0 L diesel engine. Firstly， the correctness of the calculation model is verified by experimental results of CNG-DI optical engine. Then， based on the simulation model， the effect of turbulence intensity of different combustion chamber structures on flame propagation process in CNG direct injection and the effect of double point ignition mode on flame propagation velocity in flat top combustion chamber are analyzed. The results show that the shape of combustion chamber has great influence on turbulence characteristics and concentration field distribution characteristics. The increase of turbulence intensity accelerates the flame propagation process， but excessive turbulence intensity will lead to the fracture of flame surface and insufficient local combustion， which will reduce the combustion efficiency and thus lead to the decline of indicating thermal efficiency. Double point ignition can not only increase the flame front area， but also form mutual driving effect between the two flame masses， with more sufficient combustion， so as to improve the indicating thermal efficiency. Figures and Tables | References | Related Articles | Metrics

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Study on Real Driving Fine Particles Emission Characteristics for a Heavy-duty Diesel Vehicle Based on Engine-in-the-Loop Methodology Xiaowei Wang,Xiaojun Jing,Tao Gao,Xuejing Gu,Youyuan Zhang,Linlin Wu 2022, 44 (1):  58-63.  doi: 10.19562/j.chinasae.qcgc.2022.01.008 Abstract ( 424 )   HTML ( 9 )   PDF (2014KB) ( 451 )   Save In this paper， a 7.8 L heavy-duty diesel engine is selected to run WHSC （world harmonized steady-state cycle）， hot and cold WHTC （world harmonized transient-state cycle）， as well as real driving emission test （PEMS） based on engine-in-the-loop （EIL） methodology on the engine test bench. The fine particle emissions are measured by using a particle counter which can simultaneously measure PN10 （number of particles above 10 nm） and PN23 （number of particles above 23 nm） . The results show that the transient emission of PN10 and PN23 have basically the same trends under different cycles. The specific emission of PN10 is higher than that of PN23. The PN emission of heavy-duty vehicle in the middle and high-speed and high-load range of PEMS test increases rapidly with a larger particle size， resulting in an minor difference between PN10 and PN23.In the mid-speed range， PN10 emissions are significantly higher than PN23. The engine operating points of the two test conditions of WHTC and EIL-based PEMS are quite different. The EIL-based methodology enables the assessment of PN emissions for heavy-duty vehicle PEMS test on the engine test bench. Figures and Tables | References | Related Articles | Metrics

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Research on Optimization Control Strategy for Braking Energy Recovery of a Battery Electric Vehicle Based on EMB System Jiujian Chang,Yufan Zhang 2022, 44 (1):  64-72.  doi: 10.19562/j.chinasae.qcgc.2022.01.009 Abstract ( 337 )   HTML ( 22 )   PDF (2913KB) ( 338 )   Save In order to increase the energy recovered during electric vehicle braking and reduce energy waste， a regenerative braking force distribution method based on electro-mechanical braking （EMB） system is proposed. Firstly， the current braking strength is obtained according to the signal of brake pedal， and the braking forces of the front and rear axle are obtained respectively based on the strategy for braking force distribution between the front and rear axles. Then， the fuzzy controller is created with the vehicle speed， the battery SOC and the travel of brake pedal as inputs and the proportion of regenerative braking as output， and the fuzzy controller is optimized by using PSO algorithm， with maximizing the energy recovered during braking as optimization objective. Finally， a Simulink/AVL-Cruise joint-simulation is carried out. The results show that the energy recovered is increased by 2.5% under NEDC condition and by 1.56% under CLTC-P condition. Figures and Tables | References | Related Articles | Metrics

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Analysis and Validation on the Asymmetry of Ground Contact Angle and Contact Print of Rolling Heavy-duty Tire Based on Boundary Analysis Zhihao Liu,Yixun Liu,Qinhe Gao,Xiuyu Liu 2022, 44 (1):  73-81.  doi: 10.19562/j.chinasae.qcgc.2022.01.010 Abstract ( 90 )   HTML ( 3 )   PDF (3429KB) ( 221 )   Save Based on flexible carcass model with analytical elastic foundation and with consideration of the coupling relationship between the radial and tangential deformations of carcass ring， a 2D low-frequency tire dynamics model with flexible ring is established for heavy-duty tire with high-aspect ratio. The solution method of ground-contact boundary is adopted to look into the nonsymmetrical characteristics of ground-contact angle and contact print during tire rolling movement， and an experimental validation is also conducted on the nonlinearity of ground-contact stiffness and tire print. The results indicate that the solution method of ground-contact boundary can accurately calculate the ground-contact angle and contact print， and the contact print estimation method using in-tire strain sensor can indirectly measure the contact print in the process of tire rolling movement. Figures and Tables | References | Related Articles | Metrics

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Research on Redundant Anti-lock Braking Algorithm Based on eBooster Xiaohui Liu,Liangyao Yu,Sheng Zheng,Zhenghong Lu,Jian Song 2022, 44 (1):  82-93.  doi: 10.19562/j.chinasae.qcgc.2022.01.011 Abstract ( 183 )   HTML ( 4 )   PDF (5476KB) ( 337 )   Save A semi-decoupled electronic booster （eBooster） with a pedal push rod is autonomously developed and the precise control is applied on the hydraulic pressure of eBooster based on variable gain PID control algorithm. When the antilock-braking system （ABS） of vehicle fails， the hydraulic pressure of brake master cylinder is actively adjusted based on eBooster through the estimation and monitoring of all the state variables of vehicle. A redundant ABS control algorithm is proposed based on sliding mode control with achieving the function of redundant ABS as requirements and enhancing braking strength and comfort as objectives. The mathematical models of complete vehicle， tires， eBooster， wheel braking cylinders and redundant ABS are constructed with simulations conducted， and the eBooster-based redundant ABS control algorithm is verified on test vehicle Haval 6. The results indicate that the eBooster-based redundant ABS control algorithm can well achieve the function of redundant ABS and enhance the safety of vehicle on the premise of ensuring braking strength and comfort. Figures and Tables | References | Related Articles | Metrics

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Optimal Design of Normally-open Airbag for “Out of Position” Child Occupant Gang Liu,Liang Hong,Ruhai Ge 2022, 44 (1):  94-104.  doi: 10.19562/j.chinasae.qcgc.2022.01.012 Abstract ( 148 )   HTML ( 5 )   PDF (4217KB) ( 181 )   Save Children often present a variety of “Out of Position” sitting positions when taking school buses. It is necessary to carry out the optimal design of the normally-open airbag for the condition of various child sitting positions. Firstly， the injury thresholds of the 12-year-old children are determined. The simulation model of the school bus is built and verified； and the coupling model of the school bus and the normally-open airbag is established. Then， the slouchy sitting position and the right-leaning sitting position are selected as the typical “Out-of-Position” sitting positions of the 12-year-old child occupant. Finally， for the normal sitting position， the slouchy sitting position and the right-leaning sitting position， taking the weighted injury criterion as the optimization target， based on the response surface proxy model and the improved NSGA-Ⅱ algorithm， the optimal configuration of the normally-open airbag’s main design parameters are weighed and determined， with the opening degree of the snuffle valve 199.73%， the initial pressure of the snuffle valve 1.1628×105 Pa， the height of the installation position 0.3628 m and the middle strap length 0.3152 m. Under the three types of child sitting positions， the normally-open airbag with the optimal configuration can maximally improve the safety of the 12-year-old child occupant. Figures and Tables | References | Related Articles | Metrics

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Research on Ride Comfort of an Off-road Vehicle with Compound Suspension Wen Sun,Chenyang Li,Junnian Wang,Haozhe Qian,Wentong Zhang 2022, 44 (1):  105-114.  doi: 10.19562/j.chinasae.qcgc.2022.01.013 Abstract ( 238 )   HTML ( 23 )   PDF (3008KB) ( 292 )   Save In order to solve the problem of poor ride comfort of off-road vehicle on complex roads， an air spring is added on the original suspension of an off-road vehicle to form a novel compound suspension structure in this paper. Firstly， for exploring the vibration mechanism of the suspension system of off-road vehicle， through the idealized structure analysis on the air spring and the original suspension system， a compound suspension system model incorporating air spring and coil spring in parallel is constructed. Then， according to the driving requirements of off-road vehicles， a new control strategy for switching working mode is proposed with its effectiveness verified and the control system of compound suspension improved. Finally， taking the complex road surface as the working condition of the compound suspension， with the vertical acceleration of vehicle body， the dynamic travel of suspension and the dynamic deformation of tire as evaluation indicators， the influences of the complex road surface on the ride comfort and road friendliness of the compound suspension are analyzed. The results show that with complex road surface， the off-road vehicle with compound suspension system has better ride comfort than that with traditional suspension， and the wear and tear problem of air spring in normal driving is also effectively solved. Figures and Tables | References | Related Articles | Metrics

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Vehicle Yaw Rate Estimation Based on Reliability Indexed Sensor Fusion Weihua Liao,Zhicheng He,Zujian Jiang,Tianlong Yu,Yibo He 2022, 44 (1):  115-122.  doi: 10.19562/j.chinasae.qcgc.2022.01.014 Abstract ( 225 )   HTML ( 13 )   PDF (2532KB) ( 223 )   Save The yaw rate measured by on-board angular velocity sensor is inevitably contaminated by sensor noise， and is also with hysteresis. In order to improve the accuracy of yaw rate estimation， this paper presents an estimation algorithm based on Reliability Indexed Sensor Fusion （RISF） multi-source sensor information fusion . Firstly， the yaw rate sensor’s measured value is filtered by an algorithm of adaptive cubature Kalman filter（ACKF）. Secondly， the yaw rate is estimated using kinematics method by a single track model， which takes road bank angel into account. Through this model， recursive formulas are established using velocity， front wheel steering angel and lateral acceleration as input， and also using Ackermann steering geometry's output as update value. Lastly， an adaptive Kalman filter based on RISF （RISF-AKF） is applied to fuse the filtered value with the model estimation. A real vehicle road test shows that the RISF-AKF method can estimate road bank angel precisely， and the RISF fusion value has a better performance than the single sensor processed value. Figures and Tables | References | Related Articles | Metrics

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Study on Crosswind Stability Control of High-speed Vehicle Based on Sliding Mode Theory Baoyu Liang,Yiping Wang,Xun Liu,Qianwen Zhang,Jianbo Xiong,Xingjun Hu,Jingyu Wang 2022, 44 (1):  123-130.  doi: 10.19562/j.chinasae.qcgc.2022.01.015 Abstract ( 164 )   HTML ( 8 )   PDF (2366KB) ( 272 )   Save For crosswind stability of high-speed vehicles， a two-way coupling platform of multi-body dynamics （MBD） and computational fluid dynamics （CFD） is built， and a crosswind stability control system is designed based on the platform. Based on the sliding mode theory， the upper controller calculates the additional yaw moment required for the stability of high-speed vehicle under crosswind disturbance， and the lower controller distributes the yaw moment to each wheel， so as to complete the anti-crosswind control of the vehicle. The kinematic and aerodynamic characteristics of uncontrolled vehicle and direct yaw-moment control （DYC） vehicle under step crosswind are analyzed. The results show that the maximum yaw angle of the uncontrolled vehicle is 5.7° and the maximum lateral displacement is 4.0m in the step crosswind. After DYC is applied， the yaw angle of the vehicle is basically 0 and the maximum lateral displacement is 0.41m， with the vehicle maintaining the straight driving state well. It shows that the crosswind interference resistance of high-speed vehicles is improved effectively under the crosswind stability control system. Figures and Tables | References | Related Articles | Metrics

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Analysis on the Correlation Between Human Physiological Thermal Responses and Subjective Thermal Sensation in Inhomogeneous Thermal Environment of Passenger Compartment Weijian Li,Jiqing Chen,Fengchong Lan,Hailiang Xie 2022, 44 (1):  131-141.  doi: 10.19562/j.chinasae.qcgc.2022.01.016 Abstract ( 120 )   HTML ( 14 )   PDF (3805KB) ( 343 )   Save Clarifying the correlation between occupants' physiological thermal response and thermal sensation is the imperative requirements for achieving the intelligent control of compartment thermal environment. In order to investigate the relationship between human thermal sensation and physiological thermal regulation， a passenger compartment climate test platform is constructed， a subjective thermal sensation evaluation is conducted， and a two-scale evaluation system for human thermal sensation is established through thermal sensation and thermal comfort tests. Then the physiological thermal responses including pulse rate， oxygen saturation of blood， blood pressure and skin temperature etc. are measured by the sensors the testees wear. The test data are processed and analyzed and the T check values indicate that the pulse rate and its changing rate show significant positive correlation with subjective thermal sensation with the Pearson correlation coefficient of 0.943 and 0.955 respectively； while the changing rate of mean arterial pressure and the changing rate of diastole pressure exhibit apparent negative correlation with subjective thermal sensation with the Pearson correlation coefficient of -0.955 and -0.948 respectively. Figures and Tables | References | Related Articles | Metrics

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Inverter Fault Diagnosis Method Based on Convolutional Neural Network Hai Yu,Junjun Deng,Zhenpo Wang,Fengchun Sun 2022, 44 (1):  142-152.  doi: 10.19562/j.chinasae.qcgc.2022.01.017 Abstract ( 186 )   HTML ( 13 )   PDF (3425KB) ( 236 )   Save For the risk of inverter failure in the permanent magnet synchronous motor （PMSM） drive system of the electric vehicles during long-term operation， a fault diagnosis method based on convolutional neural network （CNN） is proposed in this paper. Firstly， three-phase stator current data is normalized and filtered to an electric cycle current data， reducing the impact of variable torque and variable speed conditions of the motor drive system on the fault diagnosis effect. Then， the CNN， for the advantage of fault feature extraction and noise immunity， is used for inverter fault diagnosis. In MATLAB/Simulink， the PMSM drive system model of the electric vehicle is built. The fault injection simulation and experimental data is used to construct the dataset for the CNN， and the effectiveness of the proposed fault diagnosis method is verified. In addition， the applicability of the method is explored in the case of training sample dataset sparsification and motor model differentiation.The simulation results show that the fault diagnosis method proposed in this paper is robust and universal under the conditions of noise data and sparse data. Figures and Tables | References | Related Articles | Metrics