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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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  • 2021, Vol. 12 No. 1 Published on:31 March 2021 Previous issue    Next issue
    Review, Progress and Prospects
    Coal-based synthetic fuel and its application and technical progress in automobile engines
    SUN Wanchen, JIANG Mengqi
    2021, 12(1):  1-17.  doi:10.3969/j.issn.1674-8484.2021.01.001
    Abstract ( 600 )   HTML ( 98)   PDF (1892KB) ( 538 )  

    With the increasing number of automobiles, energy security and low-carbon development have attracted increasing attention at home and abroad. In view of the energy structure of rich coal, poor oil and less gas in China, coal-based synthetic fuel which based on Fischer-Tropsch synthesis process has become an ideal alternative fuel for automobiles due to its good combustion and emission characteristics. The popularization and application of coal-based synthetic fuel in automobile and other power machinery is of great strategic significance and application value for realizing automobile energy diversification, reducing the dependence on foreign oil, realizing efficient and clean utilization of coal resources, and reducing automobile emission pollutants. This paper introduces the development history of coal-based synthetic fuel, the key technologies of coal-based synthetic process and the current production capacity in China. Based on the relevant research results on coal-based synthetic fuel, the spray, mixing, combustion and emission characteristics of coal-based synthetic diesel used as internal combustion engine fuel are expounded. Finally, the existing problems and future development trend of coal-based synthetic fuel market application are summarized and predicted, and reasonable suggestions are put forward for the promotion of coal-based synthetic fuel and its efficient and clean application in internal combustion engines.

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    Overview of vehicle steer-by-wire system control technologies
    ZHAO Wangzhong, ZHANG Han, ZOU Songchun, XU Kunhao, LIU Chang
    2021, 12(1):  18-34.  doi:10.3969/j.issn.1674-8484.2021.01.002
    Abstract ( 696 )   HTML ( 48)   PDF (1404KB) ( 3038 )  

    Steer-by-wire system can achieve the goal of personalized driving, assistant driving and unmanned driving through control-by-wire and intelligent control technology. It is the key technology of intelligent networked vehicle landing, and its related dynamic control technology is the core technology that affects the comprehensive performance of steer-by-wire system. This paper introduces the basic structure types and dynamic modeling of the steer-by-wire system, and summarizes the road feel control technology, stability control technology, fault-tolerant control technology and steer-by-wire control technology for intelligent vehicles in full scale. The development process and research status of the steer-by-wire system are analyzed in detail. Finally, the future research trend of steer-by-wire system is prospected. It can be predicted that the control technology of steer-by-wire system will be developed in the direction of accurate execution, full condition coverage, parallel driving, safe and reliable application, and intelligent network connection.

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    Automotive Safety
    Braking strategy and simulation of electric vehicle based on traffic information
    DONG Zhenpeng, ZU Bingfeng, ZHOU Jianwei, XU Jiachen
    2021, 12(1):  35-42.  doi:10.3969/j.issn.1674-8484.2021.01.003
    Abstract ( 277 )   HTML ( 35)   PDF (2109KB) ( 203 )  

    A braking coordination strategy of electric vehicles (EV) was proposed based on traffic information to improve the economy of coasting recovery and the safety and comfort of pedal braking. After analyzed slide braking economy, the coasting intensity was determined by the traffic condition and the vehicle state information. A vehicle safety distance model and a collision warning strategy were established based on the traffic information and the forward vehicle information with the warning information being used to coordinate the coasting braking and pedal braking strength. The strategies were verified by simulation. The results show that the comprehensive energy consumption is reduced by 1.1% in good traffic conditions; the braking fatigue of drivers is alleviated in congestion conditions by using the coasting strategy based on traffic information; warning and coordination strategies avoid frequent warning and reduce the probability of triggering emergency braking. Therefore, using traffic information can assist driver to brake more reasonably.

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    Cyclist head responses in electric-bicycle-to-SUV accidents based on decision tree model
    LI Huan, BAI Zhonghao, GAO Wenrui, CHOU Clifford C., JIANG Binhui
    2021, 12(1):  43-51.  doi:10.3969/j.issn.1674-8484.2021.01.004
    Abstract ( 460 )   HTML ( 39)   PDF (1117KB) ( 286 )  

    A multi-rigid body model for electric-bicycle (E-bike) -to-SUV (sports utility vehicle) impact was used to adjust the parameters to obtain the cyclist’s head kinematic responses in different accident conditions to improve the protections on the head of cyclists. Through the C4.5 decision tree algorithm, the decision tree models of cyclist’s head kinematic responses were then created from this dataset and verified accordingly. The results show that initial impact velocity of SUV is a key factor affected the cyclist head responses. Increasing the initial impact velocity of SUV increases the cyclist’s head relative impact velocity, WAD (wrap around distance) of head impact location, and head injury criterrion (HIC15). And the WAD of cyclist’s head impact location is also significantly affected by the body size of cyclist. The WAD of head impact location becomes higher with increasing body size of cyclist. Therefore, the decision tree model will be used to predict and decision for guiding develop tests for cyclist’s head safety assessment regulatory and for investigating head protection.

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    Vehicle global path planning algorithm based on spatio-temporal characteristics of traffic
    DU Mao, YANG Lin, JIN Yue, TU Jiayu
    2021, 12(1):  52-61.  doi:10.3969/j.issn.1674-8484.2021.01.005
    Abstract ( 420 )   HTML ( 36)   PDF (1283KB) ( 255 )  

    A path planning algorithm based on spatiotemporal dynamic traffic information was proposed to reduce the travel time and energy consumption of hybrid electric vehicles (HEV). The factors that affect the vehicle travel time and the minimum energy consumption in the whole path were analyzed. The travel time and the path energy consumption are calculated based on the generalized regression network (GRNN) model. A vehicle path planning algorithm based on parallel A * algorithm was constructed to plan a shorter time-consuming or more energy-saving path for vehicles after determining the starting and ending positions. The virtual simulation test was implemented. The results show that the proposed algorithm can obtain a better travel path and reduce vehicle energy consumption by more than 11% or driving time by more than 13% compared with the calculation methods through average speed or power parameters. Therefore, the proposed algorithm can plan a better route for vehicles.

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    Localization estimation algorithm under cyber delay attack for autonomous vehicle based on LGSVL/Apollo
    FENG Minjian, ZHANG Hui, JU Zhiyang, XU Qing
    2021, 12(1):  62-69.  doi:10.3969/j.issn.1674-8484.2021.01.006
    Abstract ( 468 )   HTML ( 47)   PDF (1707KB) ( 291 )  

    An unbiased finite impulse response filter (UFIR) under delay model was proposed to improve the accuracy of autonomous vehicle location estimation algorithm under delayed attack. A vehicle kinematics model under delayed attack was established and extended to a finite length time window. A batch and iterative forms of UFIR algorithms were derived. The embedding position of the algorithm was selected by analyzing the data flow of Apollo functional modules. A co-simulation test platform was built based on LG Silicon Valley Lab (LGSVL) Simulator and Apollo system, and conducted experiments. The results show that compared with the Kalman filter (KF), the algorithm has higher estimation accuracy, faster response speed, smaller fluctuation amplitude, and stronger robustness when the delay data changes greatly. The estimation effect is great when the data delay time is less than or equal to 1 s. Therefore, the result verifies the feasibility of the autonomous driving simulation experiment based on LGSVL and Apollo system.

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    The influence of rotational speed of pedestrian head-to-vehicle collision on brain tissue response
    LIU Jinming, MA Huaxing, LI Kui, LI Guibing
    2021, 12(1):  70-78.  doi:10.3969/j.issn.1674-8484.2021.01.007
    Abstract ( 290 )   HTML ( 32)   PDF (1041KB) ( 318 )  

    A distribution of pedestrian head-vehicle impact linear/rotational speed was firstly obtained by kinematics reconstruction of 46 real world cases to investigate the effect of pedestrian head rotational speed on brain injury risk in vehicle collisions. A finite element (FE) simulations of head-to-windscreen and head-to-bonnet impacts was conducted with these data, and the brain response was analyzed under different head rotational/linear speeds and collision locations. The results show that in head-to-windshield impacts, the maximum principal stress and Von Mises stress increase with the increase of head rotational speed when the linear speed is less than 40 km/h, and the rotational speed has no significant effect on brain response when the linear speed is greater than 40 km/h; for head-to-bonnet impacts, the maximum principal stress and Von Mises stress increase with the increase of head rotational speed under all impact conditions, leading to significant increase in brain injury risk. It is suggested that the effect of head rotational speed and the difference between windshield and bonnet impact should be considered in vehicle safety evaluation.

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    Automotive Energy Efficiency and Environment Protection
    Are domestic electricity prices higher in countries with higher installed capacity of wind and solar? (2019 data)
    Gautam Kalghatgi
    2021, 12(1):  79-83.  doi:10.3969/j.issn.1674-8484.2021.01.008
    Abstract ( 317 )   HTML ( 37)   PDF (481KB) ( 907 )  

    Domestic electricity price (P) from twenty different countries in Europe, Asia and America is compared with various combinations of the total electricity generation, the installed capacity and the actual energy delivered by wind and solar (variable renewable energy, VRE) in 2019. There is a positive correlation between P and per capita installed capacity of VRE but it is weaker than reported in the past just for Europe. The strongest correlation, with an R2 of 0.71, of P is with the ratio of the maximum possible energy from wind and solar working continuously at rated capacity to the actual total electricity generation. The various correlations suggest that, though there would also be other policy options, the impact of VRE on P can be moderated by reducing the fraction of electricity supplied by VRE through the use of other CO2-free energy sources and/or more efficient VRE via higher capacity factors.

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    Energy management strategy of plug-in hybrid electric vehicle based on system comprehensive efficiency optimization
    TONG Shengwen, CHEN Tao, XIE hui
    2021, 12(1):  91-99.  doi:10.3969/j.issn.1674-8484.2021.01.009
    Abstract ( 325 )   HTML ( 39)   PDF (1580KB) ( 496 )  

    A energy management strategy for a plug-in hybrid electric vehicle (PHEV) power system was investigated according to the optimal overall energy efficiency to improve the true energy efficiency of a power system of PHEV. A system efficiency evaluation model was established to evaluate and dynamically modify the efficiency of a battery storage of electric energy aiming at the time-varying and coupling of the system's overall efficiency. A energy management strategy was constructed with the goal of optimal system overall efficiency and particle swarm optimization algorithm. The application effect of the energy management strategy was analyzed based on the GT-Suite and Simulink joint simulation platform. The results show that the optimized engine and motor operating conditions are more reasonable compared with the energy management strategy, which does not consider comprehensive energy efficiency, under two consecutive “Worldwide Harmonized Light Vehicles Test Cycles (WLTC)”; The comprehensive energy consumption is reduced by 10.6%; The distribution of the optimized engine and motor operating conditions is more reasonable; The system energy consumption is effectively reduced under different working conditions. Therefore, the energy management strategy improves the energy efficiency of plug-in hybrid power systems.

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    Tests of exhaust emission characteristics for diesel vehicles driving on the mountain road
    PENG Meichun, LIAO Qingrui, WANG Hailong, YE Weibin
    2021, 12(1):  100-105.  doi:10.3969/j.issn.1674-8484.2021.01.010
    Abstract ( 255 )   HTML ( 28)   PDF (1837KB) ( 163 )  

    Reality driving emission (RDE) tests were carried out on loads in mountains and plains for diesel vehicles of the CHINA Phase V. The data of speed, altitude, NOx and PN emission concentration, etc. were collected to investigate the influence of the slope of mountain road, the vehicle mass loads and the output power on NOx and PN emissions of diesel vehicles. The results show that NOx emission factors on mountain road with an average slope of about 6% are 20% at least higher than that on flat road, and PN emission factors are 20% at least lower than that on flat road. With the increased of gradient from 0 to 8%, NOx emission concentrations increased by more than 1 times, and PN emission concentrations increased by 20%-60%. As the gradient increases further, NOx and PN emission concentration increases slowly and then decreases. When the load increased, NOx and PN emission concentrations increase. The emission rates of NOx and PN are high in 10-40 kW region, and the high emission regions of NOx and PN become wider with increased of load. The results can provide a reference for the setting of vehicle operating conditions for RDE test.

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    Control method of switching between series and parallel drive modes of dual-motor hybrid electric vehicle
    ZHU Hao, ZHANG Tianqiang, LIU Yuanzhi, XU Jialiang
    2021, 12(1):  106-115.  doi:10.3969/j.issn.1674-8484.2021.01.011
    Abstract ( 314 )   HTML ( 29)   PDF (2314KB) ( 137 )  

    A non-power interrupt switching method was proposed based on a coordinated control of three power sources with analyzing of series and parallel driving modes for a dual-motor hybrid electric vehicle (HEV) to realize a series-parallel switching control of the dual-motor HEV. The series-to-parallel switching process includes three stages: engine operating point transferring, clutch coupling, and power source switching. The parallel-to-series switching process includes three stages: power source switching, clutch opening, and engine operating point transferring. The results show that the vehicle tests at a speed of 80 km/h verify the control method, the series-to-parallel switching process lasts 1.76 s, the switching impact is less than 10 m/s 3. and the parallel-to- series switching process lasts 2.57 s, the switching impact is less than 5 m/s 3, and there is no power interruption during the whole switching process. Therefore, the series-parallel switching control method can be successfully implementedy.

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    Simulation and analysis of large-format lithium-ion power batteries
    KUANG Ke, REN Dongsheng, HAN Xuebing, ZHENG Yuejiu, SUN Yuedong
    2021, 12(1):  116-124.  doi:10.3969/j.issn.1674-8484.2021.01.012
    Abstract ( 310 )   HTML ( 36)   PDF (2347KB) ( 392 )  

    A two-dimensional simulation model was established based on a pseudo-two-dimensional (P2D) theory to explore the inconsistency performances of large-format lithium-ion power batteries. The potential distribution and boundary conditions in the current collector region was introduced in the model to analyze electrical performance such as the rate capacity, the capacity utilization rate, the resistance, and the local lithium plating to model electrodes with the length from 10 cm to 150 cm. The results show that the voltage loss of the positive current collector reaches 0.1 V at 3 C rate for a 100-cm electrode, the charging capacity utilization rate drops to 82.2 %, and the normalized polarization internal resistance of a 100-cm battery is nearly twice as big as that of a 10-cm battery; For the 100-cm battery, local lithium plating occurs at 85 s during the charging process due to non-uniform current density; and the temperatures at the two tab-area are 8.6 K higher than that at other area due to high current density. Therefore, the optimizations of battery structural design and the thermal management system are urgently required for large format lithium-ion batteries.

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    Bi-directional circulating preheating method based on waste heat reuse of engine and battery for hybrid electric vehicle
    DING Peng, ZHOU Ye, ZHANG Meijuan, JIANG Hao, ZHNAG Pengbo
    2021, 12(1):  125-132.  doi:10.3969/j.issn.1674-8484.2021.01.013
    Abstract ( 354 )   HTML ( 31)   PDF (1154KB) ( 546 )  

    A new way to utilize the waste heat resources of engine-battery cooling was explored and a two-way cycle preheating method of waste heat reuse was conceived to improve the low-temperature survivability of engine and power battery of parallel hybrid electric vehicle and to put forward a new method of low-temperature preheating of engine and power battery. The numerical model of engine and power battery waste heat was established, the rising characteristics and distribution of the temperature in the waste heat system were quantitatively analyzed and studied, revealing the heat transfer law of engine-power battery waste heat. An automatic bidirectional thermal control device based on phase change material was designed and the low temperature test was carried out. The results show that the proposed method realizes the integrated application of engine-power battery endothermic cooling and heating, the power battery can be preheated through the heat exchanger, keeping the internal temperature of the battery at 29 ℃, and can transfer the cooling waste heat of the power battery to the engine block in reverse circulation, so as to preheat the internal coolant temperature of the engine to 51 ℃. It can significantly improve the low temperature operation ability of the engine and the power battery with saving energy, verifying the advantages of the proposed method.

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