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  • 2017, Vol. 08 No. 02 Published on:25 June 2017 Previous issue    Next issue
    Progress & Prospects
    Research status of real driving emission measurement system for vehicles
    GE Yunshan, DING Yan,Yin Hang
    2017, 08(02):  111-121.  doi:10.3969/j.issn.1674-8484.2017.02.001
    Abstract ( 235 )   PDF (2186KB) ( 1529 )  

    The real driving emissions for vehicles are highly regarded within the automotive industry. The USA, EU and China all developed the real driving emission (RDE) regulation because there are obvious differences between the real driving emission and approval appliance. This paper summarized the type and application of the portable emission measurement system (PEMS) to control the vehicle emission; introduced the CO2 moving average window method and power binning method for light-duty vehicle, the work based windows method and not-to-exceed (NTE) method for heavy-duty diesel truck to reveal the research statues of the real driving emission. Therefore, the authors recommend China government constructing a special regulation of real driving emission measurement to suit the situation of road and transportation characteristics in China.

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    Automotive Safety
    Development and tests of control strategy for four-in-one integrated automotive driver assistance systems
    CAO Libo,LIU Zhongchen,WU Jun,Yao Yuan,Feng Xiexing
    2017, 08(02):  122-127.  doi:10.3969/j.issn.1674-8484.2017.02.002
    Abstract ( 166 )   PDF (1305KB) ( 532 )  

     An integration automotive active-safety assistance-driving system, named four-in-one, was designed with less vehicle-interior-space and with less miss-alarms. The four-in-one system included four typical automotive safety systems, which are lane departure warning system, forward collision warning system, blind spot detection system, and active preload safety belt. A control strategy was developed with a control-instruction priority being determined by controller-area-network (CAN) communication-protocol based on time-to-collision (TTC) signal to complete critical-reminder and grading-pretension by advanced safety belt. A real vehicle with the integration system was tested on highway field in different weathers. The results show that the “four-in-one” system can avoid frequent alarms and simultaneous alarms with driver reminding and restricting with less driver's wrong judgments. Therefore, the injury-risk in traffic accidents can be reduced for drivers and passengers.

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    Research on human injury with THUMS model based on SAE J2114 test
    HU Yuanzhi, HE Enze
    2017, 08(02):  128-135.  doi:10.3969/j.issn.1674-8484.2017.02.003
    Abstract ( 182 )   PDF (1864KB) ( 919 )  

     Injury responses were simulated by using total human model for safety (THUMS) model to represent the real injury situation for unconstrained drivers' head and neck in rollover tests. A rollover model for complete vehicles was built by using LS-DYNA finite element (FE) simulation. The simulation results were compared with the rollover test results of an SAE J2114 dolly from the crash test data based on Ford Explorer finite element model. The results show that the risk of skull fractures and cervical fractures was low within the first 1.1 s of the simulation but with an intracranial injury possibility. Therefore, the FE model can generally reflect occupants’ injury trends and crash characteristics of real roll-over accidents. The THUMS model can simulate the dynamic response of occupants and intuitively describe the injured parts of human body, while the Hybrid III 50% male dummies' neck could not reproduce the realistic occupant kinematics in rollover.

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    Algorithm and simulation verification of longitudinal collision avoidance for autonomous emergency break (AEB) system based on PreScan
    HU Yuanzhi, LV Zhangjie, LIU Xi
    2017, 08(02):  136-142.  doi:10.3969/j.issn.1674-8484.2017.02.004
    Abstract ( 485 )   PDF (1453KB) ( 1556 )  

     Using autonomous emergency braking (AEB) can assist car-drivers to avoid longitudinal collision. Five AEB algorithms to avoid collision were compared to verify the braking effect. Four kind of safety distance algorithms included Mazda, Honda, Berkeley, and SeungwukMoon, by using the distance between the selfcar and the front-car at the end of automatic braking, to judge the braking effect. The fifth algorithm was TTC algorithm with the time to collision (TTC) judging braking effect. Simulation was performed on the active safety car simulation platform PreScan running in the Simulink software. The results show that the vertical collision avoidance performance of the TTC algorithm is the optimal one among the five under the condition of normal driving without disturbing the driver.

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    Test and characterization on mechanical properties of curing degree correlated damping adhesive
    XIA Yong,GUO Sai,QIU Rongying,YAO Li,WANG Detian
    2017, 08(02):  143-148.  doi:10.3969/j.issn.1674-8484.2017.02.005
    Abstract ( 135 )   PDF (1588KB) ( 457 )  

     Local depression deformation after curing is observed in damping adhesive structures in vehicle body manufacturing. To solve this problem, sample tests and real car measurement were conducted and material properties of damping adhesive were tested, to reveal the formation mechanisms of curing deformation. Curing characteristics, expansion behaviors and viscoelasticity properties of commonly used damping adhesive were obtained from the experiments on the material properties of damping adhesive and a series of mechanical and thermal tests. The correlations between expansion behavior / viscoelasticity property and curing degree were investigated. The results show that modulus and expansion property of adhesive are two important factors to curing deformation. The conclusion guides material selection and structural design in vehicle body manufacturing.

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    Development and application of semi-automated driving vehicle on highway
    BIAN Ning, ZHAO Baohua, LAI Feng, LIU Jifeng, CHEN Ji, ZHOU Jianguang
    2017, 08(02):  149-156.  doi:10.3969/j.issn.1674-8484.2017.02.006
    Abstract ( 229 )   PDF (1809KB) ( 1241 )  

    The advanced driver assistance system (ADAS) in longitudinal vehicle dynamics which included full speed adaptive cruise control (FS ACC), automatic emergency braking (AEB) and forward collision warning (FCW), was developed to carry on the effective exploration and for the technical accumulation for the system mass production on the developing platform of the integrated active safety system Dongfeng Fengshen AX7. By using the extended electrical power steering, lane centering assist (LC), lane keeping assist (LKA) and lane departure warning (LDW) were applied on the developing platform; more than the integrated chassis control, integrated active driving adjustment, active braking and active steering were firstly proposed and employed. FS ACC with steering intervention has been realized on highway. All of the related components, subsystems and systems on the platform were realized to be produced in mass. And the on-line test was also carried out on high way. The results shows that a low-cost technical approach for semi-automated driving vehicle on the highway is preliminarly proposed.The system is proved to be practicable.

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    Plastic mechanical behavior and constitutive modeling of high-strength steel at high strain rates
    LAI Xinghua, YIN Bin
    2017, 08(02):  157-163.  doi:10.3969/j.issn.1674-8484.2017.02.007
    Abstract ( 312 )   PDF (2001KB) ( 3219 )  

    The applicability of the model with strain-rate dependence was investigated in view of the strain rate effect of high strength steel. Using hydraulic-servo high speed testing machine, the tension tests of low alloy high strength cold rolled steel HC340LA were carried out at the intermediate-to-high strain rate (0.1~500 s-1). Finite element simulation of the material at different loading speeds was performed with non-linear dynamic explicit code LS-DYNA. Different constitutive models (e.g., Johnson-Cook, Cowper-Symonds) for depicting strain rate effect and plastic yield stress of steel material were compared. The results show that Swift-HockettSherby hardening law is preferable for characterizing the plastic flow stress behavior of high strength steel, and interpolation method is better than constitutive modeling for accurate simulation of strain rate effect of the material.

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    Vehicle rear-end collision warning algorithm based on DSRC
    CHEN Tao, FANG Wei, AN Lingfang
    2017, 08(02):  164-169.  doi:10.3969/j.issn.1674-8484.2017.02.008
    Abstract ( 215 )   PDF (1469KB) ( 389 )  

     Traditional vehicle rear-end collision warning algorithms are not able to give comprehensive consideration to false alarm rate and timeliness at the same time. A novel method of warning algorithm was proposed based on front vehicles to solve the problem, it applied dedicated short range communication (DSRC) technology to achieve a stable and efficient information exchange between vehicles. The critical safety vehicle distance was calculated by a safety vehicle distance warning model. The vehicle on board unit (OBU) transmitted the safety information to the front OBU through an adaptive broadcasting algorithm. The simulation and analysis were carried out with VanetMobiSim and network simulator version 2 (NS2). The results show that the vehicle rear-end collision warning algorithm is feasible and effective, it solves the contradiction between the false alarm rate and the alarming timeliness, and increase the road traffic safety, which has important significance to the development and improvement of vehicle rear-end collision warning system.

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    Vehicle stability control based on integrated-electro- hydraulic brake system
    HE Xiangkun, YANG Kaiming, JI Xuewu﹡
    2017, 08(02):  170-177.  doi:10.3969/j.issn.1674-8484.2017.02.009
    Abstract ( 199 )   PDF (1768KB) ( 1177 )  

    A vehicle dynamics control strategy based on integrated-electro-hydraulic brake system (IEHB) was proposed to improve the driving stability of vehicle under extreme conditions. IEHB system actuator and a 15- DoF vehicle nonlinear dynamics physical simulation model were established in advanced modeling environrnent for performing simulation of engineering systems (AMESim). A hierarchical control structure adopted: yaw moment control layer was designed by utilizing linear proportional control and nonlinear compensation control method; The design of braking torque distributing layer and actuating layer ensured tracking quality of the controlled vehicle to output of reference model layer. The results show that the proposed control method can make the plant track the reference model output under extreme conditions rapidly and accurately. Compared with vehicle dynamics stability control system based on conventional electronic stability control system (ESC), the peak tracking error of yaw rate is reduced by 13.6%, and the convergence time is shortened by 1.3 s. The performance of some vital dynamic parameters, including roll angle, sideslip angle and lateral acceleration, are significantly improved. Vehicle driving stability is optimized remarkably. Therefore, this control method can guarantee the vehicle quickly and accurately track the output of reference model under extreme driving condition.

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    Automotive Energy Efficiency & Environment Protection
    On-line correction method for SOC of Li-ion battery based on current integration method
    LIU Xiongfei,CUI Bin,LIU Junjie,LIN Yong
    2017, 08(02):  178-182.  doi:10.3969/j.issn.1674-8484.2017.02.010
    Abstract ( 221 )   PDF (1597KB) ( 1380 )  

     An on-line correction method was proposed for Li-ion battery to reduce the cumulative error from state of charge (SOC) estimation method witch is industrial commonly used. Li-ion battery discharging experiments were carried out with measuring the voltages, currents and temperatures at 0~60 ℃ with discharge rate of 1 C, 2 C, 3 C and 0.33 C to build a Li-ion battery discharge database. Open-circuit voltages were obtained using this database under SOC of 20% and 80% at the same arrange of discharge temperatures and discharge rates mentioned above to determine a straight line of SOC and open-circuit voltage. The SOC corresponding a voltage point on the straight line and a correction factor α were used to correct the SOC obtained by the current integration method. The results show that the error between estimation SOC and actual SOC is less than 4%, which meets industrial demand.

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    Analysis on performance index of battery electric passenger car in China’s tax-free NEV catalog
    2017, 08(02):  183-189.  doi:10.3969/j.issn.1674-8484.2017.02.011
    Abstract ( 175 )   PDF (1545KB) ( 556 )  

     This paper analyzed the key parameters for passenger battery electric vehicles (BEVs) to evaluate the technical level for different vehicle types, to determine the key technical parameters for new design vehicle type, and to make related policies. The data came from the 275 kinds of vehicle model from 9 batches of the catalogue of new energy vehicles (NEVs) from 2014 to 2016 with purchase-tax-exemption released by government. Analyzed the average, the maximum and the minimal value, as well as the quantity distribution with different curb mass (m) for passenger BEVs. As results, the energy consumption per 100 km is ranged at 7.60~34.84 kWh, the energy density of traction battery is 50.53~199.4 Wh/kg, the ratio (λ) is 9.95%~31.65% between traction battery gross mass and vehicle curb mass, and the consumption per mass-mileage-energy is 78.05~225.90 Wh·(km·t)-1; the ratio λ with an average value of 21.43% is much higher than the ratio between engine-mass and curb-mass for traditional-vehicles; the energy economy performances for BEVs within the mass segments of m ≤ 1 t are much higher than the value desired by Chinese government; it might make an opposite conclusion when evaluating BEVs energy consumption by using energy consumption per 100 km and by using mass-mileage-energy consumption. Therefore, it is recommend to adopt mass-based grouping limit or fitted straight-line method when regulate BEVs energy consumption.

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    Chassis dynamometer tests of particle mass emissions and particle number emissions from light-duty vehicles
    2017, 08(02):  190-197.  doi:10.3969/j.issn.1674-8484.2017.02.012
    Abstract ( 146 )   PDF (2174KB) ( 609 )  

    Particle mass (PM) emissions and particle number (PN) emissions per km were measured for 55 light-duty vehicles in China to quantitatively evaluate the particle emissions for domestic light-duty vehicles. Some diesel, gasoline direct injection (GDI) and multi-point injection (MPI) gasoline vehicles were tested on a chassis dynamometer according to the driving cycles by using the methods of laser condensation particle counting and filter paper weighing. The results show that the particle emissions of gasoline vehicles are significantly lower than those of stage 4 diesel vehicles. The PM average emission of gasoline vehicles is 6% of those of stage 4 diesel vehicles, and PN average emission of gasoline vehicles is 5% of those. The PN emissions of MPI vehicles are lower by one magnitude than those of GDI vehicles. The PN emissions of MPI and diesel vehicles increase largely due to the high-speed and long-acceleration working conditions of Worldwide Harmonized Light Vehicles Test Cycle (WLTC). The PN emission peak of GDI vehicles in the coldstart stage lasts a longer time compared with MPI and diesel vehicles. Other emission peaks occur obviously in the subsequent acceleration dynamic working conditions.

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    Effect of sensor errors on state of charge estimation for ternary lithium-ion cells
    ZHENG Yuejiu, XU Shuangshuang, ZHANG Zhendong
    2017, 08(02):  198-204.  doi:10.3969/j.issn.1674-8484.2017.02.013
    Abstract ( 211 )   PDF (1955KB) ( 1167 )  

    The accurate estimation of state of charge (SOC) of lithium-ion cells is the key technology of battery management system. The influence of SOC estimation accuracy with the drift or white noise of voltage or current sensor was analyzed to determine the sensor errors on the accuracy of SOC estimation using genetic algorithm to identify model parameters and extended Kalman filter based on the second-order RC equivalent circuit model. The results show that the relationship between offset values and the mean of SOC estimation error has an approximately linear when the voltage or current sensor has drift, but the white noise of the voltage and current sensors has no influence on the mean of the SOC estimation error. If the estimation accuracy of SOC is less than 5% for lithium-ion cell used in the experiment, the voltage and current offset should be controlled respectively within 10 mV and 1/30 C.

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    Reliability-based design optimization for lightweight design of vehicle body based on sequential Kriging model
    LI Fangyi, WEN Zhongwu, LIU Jie, RONG Jianhua, LI Fengling
    2017, 08(02):  205-212.  doi:10.3969/j.issn.1674-8484.2017.02.014
    Abstract ( 239 )   PDF (1781KB) ( 903 )  

    A reliability-based design optimization method was presented based on the sequential Kriging method to decrease the computational intensity and to improve the accuracy of the traditional reliability-based design optimization of automobile body structure for the lightweight design of vehicle body. The vehicle mass was selected as the objective of optimization, and the crashworthiness responses were chosen as the reliability constraints to establish the reliability optimization design model. The sampling data of finite element model forvehicle frontal crash was generated and calculated by using the Latin hypercube design of experiment, and Kriging models for objective and constraint functions were built up according to the simulation results to improve the computational efficiency. The sequential optimization and reliability assessment (SORA) method was used to decouple the nested optimization into a single level optimization. On each iteration, a performance measure method was adopted to evaluate probabilistic constraints based on Kriging model to enhance the computational accuracy. The results show that the method can meet the needs of the efficiency and accuracy for the engineering design, and meet the reqirements of automotive safety, light weight and reliability. The vehicle mass is reduced by about 1.4%.

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