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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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  • 2020, Vol. 11 No. 3 Published on:30 September 2020 Previous issue    Next issue
    Principles and typical applications of cloud control system for intelligent and connected vehicles
    LI Keqiang LI Jiawen, CHANG Xueyang, GAO Bolin, XU Qing, LI Shengbo
    2020, 11(3):  261-275.  doi:10.3969/j.issn.1674-8484.2020.03.001
    Abstract ( 1836 )   PDF (1241KB) ( 2603 )  
     This paper proposed the concept, structure, function and working principle of the system of coordinated control by vehicle- road-cloud Integration (as called cloud control system : CCS). It is a typical application of cyber-physical system theory in the field of intelligent and connected vehicles. The CCS has five features: ubiquitous interconnection of vehicles, roads and clouds, digital mapping of all traffic elements, global performance optimization, efficient computing and scheduling, and high reliability of system operation. It involves basic technical features such as integrated technology of vehicle – road - cloud and dynamic resource scheduling technology. Two typical applications of the CCS are introduced: Cloud-controlled Economic Driving System (CloudEDS), Cloud-controlled Traffic Control System (CloudTCS). The two system based on the technology of CCS can significantly improve the performance of vehicle driving and traffic operation safety and efficiency. The CCS needs to be designed from the top-level system planning, industrial environment construction, and unified standards. Furthermore, the implementation of technologies and industrial applications is necessary.
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    Challenges of energy transition needed to meet decarbonisation targets set up to address climate change
    Gautam Kalghatgi
    2020, 11(3):  276-286.  doi:10.3969/j.issn.1674-8484.2020.03.002
    Abstract ( 610 )   PDF (925KB) ( 600 )  
     There is widespread belief that climate change poses an “existential threat” and drastic and rapid cuts in greenhouse gas (GHG) emissions and hence fossil fuel use are needed to cope with it. However, empirical evidence shows that humanity has coped well with the past rise in temperature caused substantially by human activities. Moreover, fossil fuels supply 85% of global energy needs and replacing just 60% of these with carbon-free energy will require the world to build new capacity of around 9.4 TW CO2-free continuous power. Simultaneously, the existing energy infrastructure has to be dismantled e.g. oil, gas, coal, aviation, steel and cement industries have to be largely shut down. Such change is unlikely to happen, particularly as poorer countries try to grow their economies and continue to use fossil fuels so that global GHG levels are not likely to come down. It is perhaps better to recognise this reality and make societies more resilient to the effects of climate change. The paper will focus on transport, particularly, battery electric vehicles to illustrate some of the challenges. The focus is also on the policies in the U.K. but the general points are applicable to most other countries. 
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    Automotive Safety
    Impact energy-absorption performances of an automobile energy-absorbing-box with plate cubic-lattice core filled
    ZHANG Peng, QI Dexing, XIA Yong, LI Ying, WU Wenwang
    2020, 11(3):  287-295.  doi:10.3969/j.issn.1674-8484.2020.03.003
    Abstract ( 435 )   PDF (1319KB) ( 417 )  
     In order to meet the higher requirements of energy absorbing structure in the lightweight design of automobile, the mechanical design and impact energy absorption of plate cubic lattice are studied. Three kinds of basic cell structures of the plate-like cube, simple cube (SC), body centered cube (BCC) and face centered cube (FCC) are designed, and two composite cell structures SC-BCC, SC-FCC are obtained by combining the basic cells. The deformation mechanism and mechanical response of BCC, FCC, SC-BCC and SC-FCC lattice structures are analyzed systematically, and the energy absorption performance of four structures under 10 and 50 m/s impact velocity are evaluated and compared. The results show that the peak load of the energy absorbing box filled with plate cubic-lattice core is less than 100 kN under 4.4 m/s impact, and the average load is almost equal to the peak load, and the specific energy absorption (SEA) of the composite lattice core filled energy absorption box is higher than 32 J/g. Comparative study found that the plate-like cubic lattice has excellent impact resistance and energy absorption characteristics, and has a broad application prospect in the field of lightweight automobile passive protection.
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    Test and evaluation method of pedestrian automatic emergency braking system
    LING Guoqing, LU Chao, HAN Longfei, WANG Ruixi
    2020, 11(3):  296-304.  doi:10.3969/j.issn.1674-8484.2020.03.004
    Abstract ( 430 )   PDF (1268KB) ( 1068 )  
    A variety of pedestrians autonomous emergency braking system (AEB-P) test conditions was formulated to establish a complete test and evaluation method of autonomous emergency braking system (AEB) in line with China's traffic conditions and driver's driving behavior by using China in-depth accident study (CIDAS) passenger car accident data, drawing lessons from domestic and foreign research results and referring to AEB pedestrian test method in China new car assessment programme (C-NCAP). The AEB-P hierarchical model was established with introducing the analytic hierarchy process. And the weight coefficients was built up, which was suitable for testing and evaluating AEB-P test scenarios and the corresponding scenarios. The results show that the proposed AEB-P test and evaluation method are verified to be reasonable.
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    Construction of hybrid electric vehicle A-ECMS based on cloud model recognitionof driving intention
    DENG Tao, LUO Yuanping
    2020, 11(3):  305-313.  doi:10.3969/j.issn.1674-8484.2020.03.005
    Abstract ( 411 )   PDF (2270KB) ( 232 )  
    An energy management strategy for hybrid electric vehicles (HEV) was constructed and simulated according to the adaptive equivalent fuel consumption minimization strategy (A-ECMS) based on driving intention cloud model recognition. The cloud model algorithm was used to identify driving intentions to obtain the intention recognition results under some typical driving conditions. By using a weighted average method to establish the look-up table of equivalent factor to calculate the corresponding equivalent factors under each intention. The results show that the proposed A-ECMS strategy improves fuel economy by 1.3% compared with the A-ECMS based on SOC (state of charge) feedback under the New European Drive Cycle (NEDC). By using ECMS strategy obtains a similar fuel economy under combination condition with a better SOC stability. Therefore, the proposed A-ECMS strategy improves the practical application of the old ECMS strategy with a good reflecting for different driving intentions. 
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    Multidisciplinary design optimization of an electric vehicle door based on pole side crash 
    HAO Qi, LI Hailun, CUI Hongwei, TIAN Yunan, LIU Zhenwu
    2020, 11(3):  314-321.  doi:10.3969/j.issn.1674-8484.2020.03.006
    Abstract ( 306 )   PDF (1167KB) ( 350 )  
    A multi-objective, multi-disciplinary design optimization (MDO) of an electric vehicle door was achieved with approximate model considering the door construction stiffness characteristics, the door vibration performance, and the door pole side crash safety comprehensively. Based on a single-row two-seater electric vehicle (EV) designed newly, an effective finite element models of the vehicle and the vehicle door were established and benchmarked experiments. According to the Euro Pole Side Crash Rules, the dimensions of 9 key parts were determined as design variables using a Hammersley experiment of design (DOE) method and a main effect analysis method. Based on the radial basis function (RBF) approximate method, a global respond optimization was achieved. The results show that by using an MDO method ensures the vibration performance with a good level, reduces the door mass of 7.5% with improving validly the stiffness of door and the pole side crash safety performances.
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    Evaluation of the influences of pressure relief valve on the ventilation air flow and pressure in a passenger cabin
    WANG Fuliang
    2020, 11(3):  322-328.  doi:10.3969/j.issn.1674-8484.2020.03.007
    Abstract ( 172 )   PDF (1229KB) ( 122 )  
    The influences of the pressure relief valve (PRV) on the ventilation flow and the pressure in a vehicle passenger compartment were evaluated. Some numerical simulation of the flow field in the passenger compartment were carried out. According to the calculation results, the relationship between the opening area of the relief valve, the ventilation flow and the pressure in the passenger compartment was established. Combined with the passenger cabin inside air flow and pressure testing results, the equivalent openings and evaluation process of controlled leakage and uncontrolled leakage were established, the dynamic flow status and path in cabin and its influence on passenger comfort were analyzed based on the numerical simulation results. The results show that the leakage opening area and the pressure inside the passenger compartment, the pressure inside the passenger compartment and the ventilation flow vary according to the quadratic polynomial law. Combined with ventilation flow, pressure testing data and numerical simulation of flow field inside passenger compartment, accurate equivalent controlled and uncontrolled leakage openings can be obtained. Therefore, this method can be used to design relief valve and to evaluate the flow state and comfort of passenger compartment
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    Design of AFS variable steering ratio considering road adhesion coefficient and vehicle speed
    LI Xueyun, ZHANG Ju
    2020, 11(3):  329-336.  doi:10.3969/j.issn.1674-8484.2020.03.008
    Abstract ( 248 )   PDF (2841KB) ( 204 )  
     A variable steering system transmission ratio function was proposed based on considering vehicle speeds and road adhesion coefficients to improve the steering portability at low speed and the steering stability at high speed of vehicles. After analyzed the design process of an ideal transmission ratio curve and the drive mechanism of active front steering (AFS) system, proposed some solutions including: (1) Modifying the ideal yaw rate gain according to the error variation law between the actual yaw rate gain and the ideal yaw rate gain of the vehicle positive; (2) Considering comprehensively the influence of vehicle speeds and road surface adhesion coefficients on transmission ratio with the help of deriving the functional relationship between road surface adhesion coefficients and vehicle speeds and transmission ratios. A simulation model was built for vehicle trajectory tracking in a Carsim/Matlab platform to simulating. The results show that the designed transmission ratio function can calculate the reasonable transmission ratio of steering system at different vehicle speeds and different road adhesion coefficients on low adhesion roads. Therefore, it improves the handling stability and steering portability for vehicles. 
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    Improved SSD algorithm for real time target vehicle detection in ADAS
    JIAO Xin, YANG Weidong, LIU Quanzhou, LI Zhanqi, JIA Pengfei
    2020, 11(3):  337-344.  doi:10.3969/j.issn.1674-8484.2020.03.009
    Abstract ( 250 )   PDF (1006KB) ( 430 )  
    An improved real-time target-vehicles detection algorithm SSD-P was developed focusing on overlapping small target-vehicles in actual traffic scenes to improve the detection accuracy using an advanced driver assistance system (ADAS). This algorithm was based on two methods: 1) a resolution reconstruction method of shallow feature image was proposed by increasing the number of small target feature extraction; 2) a quadratic determination method with embedded feature vector in non-maximal suppression to overcome the problems such as low precision and weak ability of overlapping target detection in a single shot multi-box detector (SSD) algorithm. Experiments were carried out in PASCAL VOC2012 data set, virtual traffic scene and real traffic scene. The results show that the mean accuracy precision (mAP) for target vehicle detection is 92.4% by using SSD-P algorithm, this is 4.8% higher than that by using the original SSD algorithm. Therefore, the SSD-P algorithm can improve the accuracy of ADAS.  
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    Predictive neural network model of diesel combustion based on Bayesian regularization
    XIE Hui, NIE Zhenhua, CHEN Tao
    2020, 11(3):  345-354.  doi:10.3969/j.issn.1674-8484.2020.03.010
    Abstract ( 332 )   PDF (1199KB) ( 413 )  
    A method to calibrate multiple Wiebe's heat release rate model was proposed by building predictive neural network model of combustion based on Bayesian regularization to solve the problem that Wiebe's combustion model needed to go through a lot of point-by-point parameter tuning and its universality and predictability was poor. ModeFRONTIER was used to pre-calibrate part points of the multi-Wiebe combustion model, which provided data for the establishment of combustion prediction model. The sensitivity analysis between operating condition boundary parameters and model calibration parameters was carried out, and the relationship between them was established by using the neural network based on Bayesian regularization, which endowed the multiple Wiebe combustion models with prediction and reduced the calibration workload of the combustion model. The results show that the average accuracy of the combustion prediction model is 93.2%, and the prediction accuracy of some operating points is more than 97%, manifesting that the neural network combustion prediction model has high model accuracy and model generalization ability.
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    Effect of dilution ratio on size distribution of particles in the emission of premixed burner
    ZHANG Shuaihu, GAO Yunqi, GUO Yuejie, ZHAO Jingyi, CHEN Longfei
    2020, 11(3):  355-361.  doi:10.3969/j.issn.1674-8484.2020.03.011
    Abstract ( 314 )   PDF (958KB) ( 356 )  
    The influences of the dilution ratio on the particle size distribution in the exhaust gas of diesel engines were investigated to measure the number concentration and the size of particulate matter in the premixed combustion exhaust. A small-size injection dilutor was used to control the dilution rate. The size distributions of nano particles in premixed combustion emission of methane and ethylene were measured by using the scanning mobility particle sizer. Transmission electron microscope was used to observe the microscopic morphology and analysis the size distribution. The results show that the particle size of methane combustion exhaust gas is mainly about 40 nm, and its concentration can reach up to 108 /mL; the particle size of ethylene combustion exhaust gas is about 250 nm, and its concentration reaches 107 /mL. When dilution rate increases, the particle number concentration first increases and then decreases, and the particle size distribution will also change, which will cause the measurement results to deviate from the actual results.
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    Parameter matching and control strategy of multi-energysource for fuel-cell for electric bus
    YANG Kun DONG Danxiu, WANG Jie , MA Chao, LI Yuewei , LIU Guodong
    2020, 11(3):  362-370.  doi:10.3969/j.issn.1674-8484.2020.03.012
    Abstract ( 243 )   PDF (1283KB) ( 201 )  
    For development of fuel cell electric buses with multi-energy-source composite, taking multi-energysource composite of fuel-cell + power-cell + ultra-capacitor as research object, a vehicle mathematical model was built based on MATLAB/Simulink/Stateflow. Based on power index, economy index and characteristics of three energy sources, parameter matching and checking of multi-energy-source system were completed. Based on principle that fuel cell is main energy source, battery is auxiliary, and ultra-capacitor prevents overload of fuel cell and battery, control strategy of logic threshold was proposed. And simulation verification was finished under Chinese typical city circle and Changchun driving cycle. Simulation results show that maximum vehicle speed is 73 km/h, maximum climbing gradient is 22%, and acceleration time from 0 to 50 km/h is 16.7 s. Driving range under Chinese typical city circle is 263 km and that in Changchun driving cycle is 282 km and power and economic indexes of vehicle exceed design requirements.
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    Equivalent consumption minimization strategy for PHEV based on driving condition adaptation
    LIU Lingzhi, ZHANG Bingzhan, JIANG Tong
    2020, 11(3):  371-378.  doi:10.3969/j.issn.1674-8484.2020.03.013
    Abstract ( 287 )   PDF (2403KB) ( 335 )  
    The driving condition adaptability method of instantaneous optimal energy management strategy was proposed to improve the fuel economy of plug-in hybrid electric vehicle (PHEV). The driving condition identification model was established based on back propagation (BP) neural network algorithm. The equivalent fuel factor sequence of standard driving condition was obtained by using dynamic programming algorithm under the constraints of battery power balance. According to the real-time identificated results of the model and the state of charge (SOC) of battery, the real-time application of the equivalent consumption minimization strategy (ECMS) was realized by using the interpolation method to solve the equivalent fuel factor at this time. The results shows that the proposed method can improve fuel economy and ensure battery power balance comparing with  the traditional equivalent consumption minimization strategy without considering the condition identification, and the fuel economy under 5 driving conditions are improved by 2.2%, 2.5%, 3.3%, 2.4% and 4.0%, respectively. 
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    Estimation of state of charge for power battery based on an unscented Kalman filter algorithm 
    WANG Chao, CHEN Dehai, WANG Yuzhao, ZHU Zhengkun, ZOU Zhengming
    2020, 11(3):  379-389.  doi:10.3969/j.issn.1674-8484.2020.03.014
    Abstract ( 361 )   PDF (1513KB) ( 570 )  
    A new battery capacity calibration method was proposed to estimate the state of charge (SOC) of power batteries online with combining an unscented Kalman filter (UKF) algorithm. The actual capacities of the batteries were calibrated according to temperature coefficient and current probability, a second-order RC equivalent model was established to simulate the dynamic response characteristics of the battery, and to call the unscented Kalman filter (RLS-UKF) algorithm of recursive least squares with forgetting factor to estimate battery SOC online. The estimation process considered the influence of the change of the OCV (open circuit voltage) -SOC curve caused by the sudden current change. The DST (dynamic stress test) working conditions and the constant current conditions were used to verify the algorithm’s accuracy through MATLAB simulation model. The results show that the RLSUKF algorithm has an average error of 1.2% at DST cycle conditions, and of 1.41% at constant current discharge conditions. Therefore, the method has a better prediction effect than the current mainstream prediction methods.
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    Numerical analysis of thermal runaway of lithium-ion battery by heating form polar
    XU Xiaoming, YUAN Qiuqi, ZHANG Yangjun, HU Hao
    2020, 11(3):  388-396.  doi:10.3969/j.issn.1674-8484.2020.03.015
    Abstract ( 518 )   PDF (1071KB) ( 305 )  
    A thermal-chemical coupling model of lithium-ion batteries was established in a COMSOL software to investigate the thermal runaway characteristics of lithium-ion batteries at local high temperatures. The model contains five side reactions: the solid electrolyte interface membrane decomposition reaction, the reaction between negative electrode active material and electrolyte, the reaction between positive electrode active material and electrolyte, the electrolyte decomposition reaction, and the binder decomposition reaction. By using this model analyzed the influence of local high temperature on the heat generation of the side reactions of the lithium-ion battery and the temperature distribution of the diaphragm. The results show that heating only a single tab does not cause thermal runaway inside battery; All the five side-reactions generates heat when heating simultaneously both ends of lithium-ion battery tabs, this phenomenon will lead to trigger battery thermal runaway; Thermal-runaway inside lithium-ion battery propagates firstly in the horizontal direction and then in the vertical direction. 
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    Strategy of fast charging of lithium-ion batteries without lithium plating in a wide temperature range
    ZHOU Xuan, ZHOU Ping, ZHENG Yuejiu, HAN Xuebing, CHU Zhengyu, LIU Jinhai, YANG Yinghua, XUE Gang
    2020, 11(3):  397-405.  doi:10.3969/j.issn.1674-8484.2020.03.016
    Abstract ( 540 )   PDF (2051KB) ( 717 )  
     A calibration method of fast charging map without lithium plating for power lithium-ion battery was proposed to solve the safety problem of lithium-ion battery fast charging. Based on the potential criterion, the threshold value of negative electrode potential without lithium plating was set up by using the reference electrode to monitor the negative potential. Five fast charging strategy curves were obtained by adjusting different charging initial temperature points. State of change-temperature-current contour map (SOC-T-I Map) is obtained with piecewise linear interpolation method. The contrast experiment of rapidity and the cycle experiment of 25 ° C fast charging strategy were designed to verify the map's rapidity and no lithium plating. The results show that the fast charging strategy is 45.3% and 18.0% shorter than that of constant current 1 C and 1.5 C at 25 ° C. After 200 fast charging cycles, the differential curve of relaxation voltage has no minimum value, and the battery maintains a capacity retention rate of 99.7%, indicating that there is no metal lithium plating. The method of calibrating the current map provides the idea of mining the fast charging ability of the battery, and the calibrated map is suitable for fast charging of electric vehicles under diffident working conditions. 
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    Cooling strategy of a dual fuel injector needle valve under micro pilot ignition condition 
    HE Ping, RUAN Haoda , MEI Jiahua , WANG Congyang , LI Zhaoyang
    2020, 11(3):  406-412.  doi:10.3969/j.issn.1674-8484.2020.03.017
    Abstract ( 204 )   PDF (742KB) ( 306 )  
     The cooling effect of needle valve was investigated to improve the durability and reliability of an engine injector under micro pilot ignition condition. The temperature fields of an injector needle valve were simulated in a dual fuel mode of heavy oil and natural gas by using a multiphase flow model and a k-ε standard turbulence model in a CFD (computational fluid dynamics). The cooling effects of different inlet temperature of cooling lube were simulated numerically and verified experimentally. The results show that the needle valve head has the highest temperature point at the needle valve bottom. The cooling effect of needle valve enhances at beginning and decreases at following when the inlet temperature of cooling lube increases continuously. The needle valve head reaches its lowest temperature of 256.8 ℃ for heavy oil mode and of 361.1 ℃ for natural gas mode, when the inlet temperature is 80 ℃ , so that having the best cooling effect. Therefore, it is feasible to investigate the cooling performance of the needle valve of dual fuel engine with CFD numerical simulation method. 
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