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Welcome to Journal of Automotive Safety and Energy,
汽车安全与节能学报

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  • 2019, Vol. 10 No. 3 Published on:30 September 2019 Previous issue    Next issue
    Progress & Prospects
    Review and Some Perspectives on Different Methods to Estimate State of Charge of Lithium-Ion Batteries
    Gregory L. Plett
    2019, 10(3):  249-272.  doi:10.3969/j.issn.1674-8484.2019.03.001
    Abstract ( 553 )   PDF (3113KB) ( 3670 )  

    Battery-management systems (BMS) must continuously update estimates of state-of-charge (SOC) in order to compute and calibrate estimates of state-of-health, state-of-energy, and state-of-power (state-offunction), and to prevent cell overcharge and undercharge conditions. There are many methods used to estimate SOC, with some having advantages over others. This paper reviews different SOC-estimation approaches for lithium-ion batteries and hopes to provide the reader with perspectives and insights based on experience working in the field. The physical significance of SOC was described, which can help distinguish between methods to estimate physical SOC versus engineering SOC. Different estimation approaches were discussed in some detail. The problem of defining a battery-pack SOC metric was presented and effcient methods to compute cell SOC for every cell in the pack were reviewed. Finally, some perspectives on the present state of the art and on needed future work in the area were presented.

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    Electrification of automobile and construction of electricityhydrogen binary secondary energy network for automobile transportation
    YU Zhuoping, DU Runben, WANG Xueyuan, WEI Xuezhe
    2019, 10(3):  273-284.  doi:10.3969/j.issn.1674-8484.2019.03.002
    Abstract ( 265 )   PDF (1730KB) ( 943 )  

    The status of new energy vehicle technology and the existing hydrogen-electricity energy and infrastructure construction are analyzed. The technical difficulties brought by the transformation of automotive energy network is also discussed, The concept of traffic electric-hydrogen binary secondary energy network is proposed to achieve the goal of optimizing energy conversion efficiency chain and circulating the material utilization in transportation area. The three technical problems of renewable energy power stability, energy consumption and large-scale concurrent charging of electric vehicles are analyzed, and corresponding solutions are also proposed. Since both of the electric energy and hydrogen energy have the characteristics of widerange of sources, renewable, emission and pollution controllable, it has become the key point for the future transportation and energy technology to build an automotive power system with electrification as the core and an energy network system with two secondary energy sources of electricity and hydrogen.

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    Automotive Safety
    Nonlinear suspension predictive control based on piecewise affine model
    HU Qiguo, LU Wei
    2019, 10(3):  285-292.  doi:10.3969/j.issn.1674-8484.2019.03.003
    Abstract ( 163 )   PDF (3238KB) ( 380 )  

     An active control method for the vehicle nonlinear suspension was proposed based on the multimodel predictive control to avoid the suspension breakdown when the vehicle passes through the rough road. A 1/4 nonlinear suspension model was established with a linear piece wise affine (PWA) model related to the active force and the body displacement by using data clustering and parameter identification based on the improved particle swarm algorithm. The rolling time domain optimal control problem of the semi-active suspension was investigated based on the multi-model predictive control theory to obtain the optimal control signals. The simulation of random road and sinusoidal road surface was carried out in Matlab/Simulink. The results show that the adoption of multi-model control could make the vehicle maintain stable body posture when driving through the rough road, and the suspension dynamic travel is well controlled at the same time, which reduces the probability of suspension breakdown. 

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    Two continuum damage mechanic models for characterization of plain woven carbon fiber composites
    LIU Zeng, WEI Xinqi, XIA Yong
    2019, 10(3):  293-299.  doi:10.3969/j.issn.1674-8484.2019.03.004
    Abstract ( 347 )   PDF (2685KB) ( 529 )  

    After discussed two continuum mechanic models – Mat58 and Mat261 in Ls-Dyna for mechanical characterization of plain woven composites, the characteristics of these two material models were compared and analyzed by incorporating both experiment and finite element (FE) simulation of off-angle tension and punch test. The results show that better performance can be expected from Mat261 than that from Mat58 in simulation of off-angle tension since direct input of shear stress versus strain curve is allowed in Mat261. Due to the possession of complex failure criterions for Mat261 compared with Mat58, higher of accuracy can be reached for simulation with Mat261 of punch which presents complex stress failure states. Simulation of axial crushing of corrugated plate with Mat261 is conducted and satisfactory results, with a difference of 4.2% for specific energy absorption between the simulation and the experiment. Therefore, this verifies the advantage and feasibility of model Mat261.

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    Kinematic analysis and optimization synthesis for double front axle steering mechanism
    WANG Chengzhi, WANG Yunchao
    2019, 10(3):  300-307.  doi:10.3969/j.issn.1674-8484.2019.03.005
    Abstract ( 301 )   PDF (2287KB) ( 357 )  

    An analytical co-relationship between the steering angles of the steering wheels in a double front axle steering vehicle was deduced by using space coordinate transformation theory to optimize a steering mechanism. A design problem of the steering mechanism was optimized and improved mathematically in a double front axle steering vehicle according to the Ackermann′s principle, by taking the maximum absolute value of steering error as the objective function, with the help of visualization technology such as contour maps of the maximum absolute steering errors of wheels and the minimum transmission angles in steering mechanism. The results show that the absolute steering errors on all steering wheels are less than 1.18° in allowable range of the wheel steering motion, and the steering trapeziums have a suitable minimum transmission angles. This method avoids the blindness in optimization process, and is easy to get suitable trapezoidal parameters that meet actual conditions. The suggestions are taking suitable steering trapezium arm length as the lower limit of optimization, and ensuring the steering wheels exactly fulfill the pure rolling at three positions when vehicle travelling.

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    Analysis of the optimization trend of restraint system in two car oblique crash
    CAO Libo, ZHANG Chao，YAN Lingbo, DAI Hongliang, ZHANG Ruifeng
    2019, 10(3):  308-316.  doi:10.3969/j.issn.1674-8484.2019.03.006
    Abstract ( 199 )   PDF (4095KB) ( 423 )  

    Some driver restraint system models were developed for sport utility vehicle (SUV), medium-sized car and small-sized car to explore the optimization trend of restraint system in car-to-car oblique crash of 30°. The restraint system optimizations were conducted based on the sensitivity factors for the subject vehicle, the partner vehicle and the combination with the consideration of crash compatibility by minimizing the sum of weighted injury criterion (WIC) value of both. The results show that to the types of the vehicles mentioned above, there are certain optimization trends for the factors of restraint system: the air bleed area and mass flow of airbag tend to increase, the seatbelt force limit tends to decrease, and the pre-tensioner action time tends to be postponed. During the combined optimization, the parameters’ optimization trend is closer to that of the vehicle with the larger initial WIC value.

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    Design method of vehicle body stiffness chain combined with strain energy analysis
    ZHUANG Hongjie, LIU Zijian, ZHONG Haolong, LIU Yu
    2019, 10(3):  317-325.  doi:10.3969/j.issn.1674-8484.2019.03.007
    Abstract ( 247 )   PDF (2281KB) ( 1075 )  

     A conceptual design process of vehicle body structure was presented with a simplified space frame model being established since conceptual design is important for vehicle body design. A stiffness chain model of vehicle body was established by using a semi-rigid beam and transfer matrix method. The strain energy and strain energy density of the optimized beam element were analyzed by solving the optimization model with constrains only including the static and dynamic performance. The coefficient of variation was introduced as the constraint index to coordinate and optimize the utilization and distribution of materials under multiple working conditions. The design method considered the vehicle body semi-rigid beam stiffness chain and the strain energy factor. Body lightweight was taken as the objective function, and the vehicle body static stiffness, natural frequency, and the uniformity of the strain energy density at each working condition were taken as constraints for optimization. The genetic algorithm was used to solve the optimization problems and determine the main crosssection parameters. The results of the design method were compared with the simulation results of benchmark vehicle. The results show that the uniformity of strain energy density can improve the utility of the material and the performance of the vehicle body. Therefore, the design method is feasible. Key

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    Lateral and longitudinal motion control of unmanned vehicles using model predictive control
    XIE Hui, LIU Shuangshuang
    2019, 10(3):  326-333.  doi:10.3969/j.issn.1674-8484.2019.03.008
    Abstract ( 332 )   PDF (1910KB) ( 1573 )  

     A coordinated lateral and longitudinal control method was developed by using a model predictive control (MPC) to solve the motion control with high nonlinearity and strong coupling for unmanned vehicles. According to the curvature of the reference path, the reference speed profile was determined, and then tracked by a layered longitudinal controller. An upper longitudinal controller was used to calculate the desired acceleration through the MPC, while a lower controller was used to coordinate the driving and braking by an inverse-longitudinal-dynamic-model. A lateral controller was used to predict the changes of the system state based on the kinematic model to solve the vehicle front- wheel steer- angle when taking the current system state and a longitudinal-velocity-prediction-sequence as the inputs. The simulation results show that the root mean square error is 0.086 km/h for longitudinal vehicle speed compared to the reference speed, and is 94 mm for lateral position compared to the reference path. Therefore, this method achieves an effective control of vehicle motion.

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    Algorithm for lane region segmentation based on fullyconvolutional-network
    WEI Minxiang, TENG Decheng
    2019, 10(3):  334-341.  doi:10.3969/j.issn.1674-8484.2019.03.009
    Abstract ( 224 )   PDF (1755KB) ( 452 )  

     A method of implementing lane region segmentation was proposed by using fully convolutional network (FCN) for lightweight and real-time detection of intelligent vehicles with a high accuracy and robustness of lane recognition. A symmetry-structured fully convolutional network was used to predict the lane area pixel by pixel: the convolution and pooling were used to extract the lane features, and the up sampling wes aided by pooling indices, and convolution were used to recover the feature information. Under the established network structure, the effects of convolution kernels of 3×3, 5×5 and 7×7 sizes on the performance of the model were compared. The FCN with skip layers and the FCN without skip layers were compared with the proposed network based on FCN-32s and FCN-16s. The results show that the proposed algorithm is accurate, robust and accurate in real-time processing, and the segmentation is better than traditional FCNs. The small convolution kernel (3×3) method has the best real-time handling speed of 53 frames per second among the three different sizes. Therefore, the proposed algorithm is suitable for road perception for autonomous driving.

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    Analysis on the factors of affecting the estimation accuracy of lithium battery's state of charge
    ZHANG Zhuo, LIU Jianyu, WANG Luping, JIN Peng
    2019, 10(3):  342-348.  doi:10.3969/j.issn.1674-8484.2019.03.010
    Abstract ( 206 )   PDF (2607KB) ( 311 )  

    A hybrid pulse power characteristic (HPPC) experiment was carried out on a battery pack composed of three lithium iron phosphate batteries to investigate the different effects of various factors causing the state of charge (SOC) estimation error. A second-order Thevenin battery model was used to construct a state equation, and SOC was estimated using the unscented Kalman filter (UKF) algorithm, and the influences of the errors of the model parameters, input current, terminal voltage, and open circuit voltage (OCV) on SOC estimation were analyzed. The results show that the SOC estimation error is 19.1%, 20.6% and less than 3%, when 1% noise is added to the OCV, terminal voltage, and input current, or when the parameters of the battery (ohm internal resistance, polarization resistance, polarization capacitance) are fixed, respectively, showing that the OCV and the terminal voltage have a great influence on the SOC estimation accuracy. The estimation error of the SOC of the lithium battery can be greatly reduced by the improvement of the measurement accuracy of the terminal voltage and the accuracy of the OCV curve fitting.

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    Automotive Energy Efficiency & Environment Protection
    Simulation analysis of control algorithm for dual three-phase permanent magnet synchronous motor
    LI Weichao, MENG Yonggang, GAO Dawei
    2019, 10(3):  349-356.  doi:10.3969/j.issn.1674-8484.2019.03.011
    Abstract ( 378 )   PDF (4327KB) ( 528 )  

    Since dual three-phase permanent magnet synchronous motor (DTP-PMSM) has strong electromagnetic coupling in natural coordinate system with complex control model, a vector control algorithm of the DTP-PMSM was explored and a model of the DTP-PMSM was established based both on a space vector decoupling theory and on a double-dq transform theory to analyze the relationship and the difference of the two algorithms. A control model was built on a simulation platform of the motor with realizing a constant speed control for the two vector control algorithms. The differences of control performance between the two vector-control-algorithms were compared through analyzing simulate results. The results show that the spacevector decoupling-control and the dual-dq transform control are highly consistent in theory. The space-vector decoupling control algorithm can achieve a better energy decoupling-control relative to the dual-dq transform control algorithm.

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    Research on full speed range adaptive cruise control
    HU Yuanzhi, DING Xiaomu, LIU Xi, LI Hao
    2019, 10(3):  357-365.  doi:10.3969/j.issn.1674-8484.2019.03.012
    Abstract ( 238 )   PDF (2923KB) ( 637 )  

     A full speed range adaptive cruise control (FSRA) strategy was designed based on the requirement of BS ISO-15622 to improve the practicality of the adaptive cruise system. Based on the existing vehicleto-vehicle spacing strategy, the acceleration of the preceding vehicle was used as a reference factor to design a follow-up strategy that meets the characteristics of the driver. Taking the following efficiency, safety, comfortability and economy as the control target, model predictive control (MPC) was used to design the controller which met multi-objective optimization. The real time test platform was built in the environment of SCANeR, Matlab/Simulink, veDYNA and NI-PXI system to test and verify the control method. The results show that the control method can complete the vehicle control well in the full speed range.

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    Simulations and experiments of effect of deep Miller cycle on a turbocharged gasoline direct injection engine
    CHEN Hu, JIA Ning, LIU Xiaoping, LIU Yongliang, LI Zefeng, HU Guorui
    2019, 10(3):  366-373.  doi:10.3969/j.issn.1674-8484.2019.03.013
    Abstract ( 249 )   PDF (5273KB) ( 392 )  

     The effects of deep Miller cycle (DMC) on fuel consumption, power and emissions were invest- igated to reduce the fuel consumption of an 2.0-L in-line four cylinders gasoline direct injection (GDI) original engine by simulation and experiment. The cam lift , phase position and higher compression ratio (CR) for DMC were optimized wih one-dimensional simulation software, and the tumble motion and atomization characteristic were analyzed with computational fluid dynamics (CFD) software, and the effects of DMC on combustion performance, pumping mean effective pressure (PMEP), brake specific fuel consumption (BSFC), power, emission and others were investegated with design of experiment (DOE). The results showed that the fuel consumption of the engine were greatly reduced in the middle and small load areas by using the DMC. The fuel consumption of the vehicle with the engine were reduced 4.1% under the New European Driving Cycle (NEDC) by the ananlysis with the one-dimensional simulation.

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    Automotive Energy Efficiency & Environment Protection
    Experiments and modeling on the fuel consumption consistency of a front-engine front-drive vehicle
    LIANG Wei, MAN Xingjia, WANG Wei
    2019, 10(3):  374-382.  doi:10.3969/j.issn.1674-8484.2019.03.014
    Abstract ( 162 )   PDF (2246KB) ( 266 )  

     A fuel consumption consistency problem was analyzed for a front-engine front-drive (FF) vehicle with a poor fuel consumption (FC) consistency to meet the four-stage fuel consumption limit and corporate average fuel consumption (CAFC). A vehicle energy flow method was used to simulate and test an idle fuel consumption and a subsystem interchange to eliminate some influencing factors such as engine, gearbox and exhaust system. The source of fuel consumption differences was focused on the electrical system through disconnected motor tests. Generator efficiency was tested to eliminate the impact of generators on power consumption. The results show that electrical power consumption accounts for 34%, and battery charging power consumption accounts for 66%. Therefore, the difference in power consumption comes from electrical appliances and batteries, and the initial charge of battery is the major factor. 

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    Fast charging method of vehicle lithium battery based on three-stage optimization method
    CHEN Dehai, ZOU Zhengming, WANG Chao, HUA Ming
    2019, 10(3):  383-390.  doi:10.3969/j.issn.1674-8484.2019.03.015
    Abstract ( 211 )   PDF (1619KB) ( 679 )  

     A three-stage optimization method was proposed for constant current constant voltage (CCCV) charging to improve the charging speed and the charging efficiency of on-board lithium batteries. The threestage optimization method was modified based on the battery charging model of the Next Generation Automotive Cooperation Program (PNGV). The polarization voltage and the open circuit voltage were used to correct the control object in the constant current and constant voltage process, so that the current and voltage change in real time with the actual state of charge of the battery. An implementation scheme was designed on an embedded chip STM32F103 platform. Experiments with 4 different charging methods were performed. The results show that compared with the other three charging methods, the three-stage optimization method can increase the charging efficiency to 94.25%, and the charging time can reach 900 s, and the battery capacity attenuation value is reduced by 45% compared with the un-optimized. Therefore, the method has a good fast charging effect.

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