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  • 2016, Vol. 07 No. 03 Published on:25 September 2016 Previous issue    Next issue
    Developing trends of automotive safety technology: An analysis based on traffic accident data
    LI Yibing, SUN Yueting, XU Chengliang
    2016, 07(03):  241-253.  doi:10.3969/j.issn.1674-8484.2016.03.001
    Abstract ( 601 )   PDF (2781KB) ( 4505 )  

    Along with the development of economy and vehicle technology, traffic accidents have some particular characteristics including the high mortality of vulnerable road users and ‘nonstandard groups’ of people, crash incompatibility, high death rate of single-vehicle accidents, and a significant number of accidents caused by drivers’ insufficient perception. The developing trends of active safety technologies and passive safety technologies in terms of each subsystem by analyzing the traffic accident data in China, Europe and the United States since 2000. The main trends of passive safety include protection on vulnerable road users, adaptive passenger protection, crash compatibility and adaptive crashworthiness. The main trends of active safety include vehicle dynamic management and intelligent driving assistant. The comprehensive safety technology integrating the active and passive safety will be an important trend for the development of future vehicles.

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    Automotive Safety
    Design of a Head and Neck Restraint System for Use in City Cars
    David HENDERSON, ZHOU Qing
    2016, 07(03):  254-264.  doi:10.3969/j.issn.1674-8484.2016.03.002
    Abstract ( 217 )   PDF (2744KB) ( 601 )  

    City cars have various advantages in urban commuting and have become increasingly popular in Europe, Japan and China. However, due to their small size, city cars face significant challenge with collision protection. A new type of head and neck restraint was envisioned for providing similar motion control to that of race car systems but in such a way that it can be used in passenger cars. The concept of the design and its working principle were described in this paper. A rigid body model of the head restraint was developed to evaluate the requirements of an airbag inflator that can quickly deploy the system in a side impact and an energy
    analysis was used to comment on the feasibility of such a system. The results show that an airbag with a rate of pressure increase approximately four times that of a standard frontal airbag was sufficient to deploy the system within 15 ms. This new concept of head and neck restraint system will need further design and validation in application.

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    Risk assessment of vehicle ABS defects based on a modified fuzzy FMECA method
    CHEN Yuzhong, DONG Honglei, LI Chenfeng, LI Hui, ZHANG Bo
    2016, 07(03):  265-271.  doi:10.3969/j.issn.1674-8484.2016.03.003
    Abstract ( 330 )   PDF (2170KB) ( 1149 )  

    The defects of vehicle Anti-Lock Braking System (ABS) seriously affect the vehicle safety, and these cause defective vehicles' recall. But it is difficult to obtain accurate quantitative results according to the fuzzy description in defect hazard assessment with a traditional FMECA (Failure Mode, Effect and Criticality Analysis)
    method. After analyzed the defect modes of vehicle ABS, a modified fuzzy FMECA method was proposed by using fuzzy comprehensive evaluation method in FMECA with establishing three fuzzy evaluation indexes of defect severity, occurrence and detectability. The defect harm degrees of six failure modes were ordered taking
    an ABS motor as an example of defect risk assessment. The result shows that the modified fuzzy FMECA method can assess the risk of defects more accurate than traditional FMECA method because of considering the Risk Priority Number (RPN) of three defect fuzzy evaluation indexes. Therefore, by using this modified method can assess the vehicle brake system defects risk, and also has a positive meaning to improve the vehicle recall management efficiency.

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    Reliability optimal design of B-pillar for a hybrid electric vehicle in side impact
    CAO Libo1, LIU Heng, WU Hequan
    2016, 07(03):  272-278.  doi:10.3969/j.issn.1674-8484.2016.03.004
    Abstract ( 218 )   PDF (2340KB) ( 1558 )  

    A reliability optimization design was done for a B-pillar of a hybrid electric vehicle in side impact. The design combined using of experiments, the response surface models, the reliability theory and the reliability of design optimization method based on the product quality engineering, according to the side impact test regulations of the China New Car Assessment Program (C-NCAP) and the United States New Car Assessment Program (US-NCAP), and using the statistics from domestic and international traffic accident investigation. The design variables were considered choosing the dimensions (such as thicknesses) and the materials (such as yield strengths) of the inner panel, the outer panel and the reinforcing plate, which play a major role in the safety performance in side impact crashes. The results show that this design makes the B-pillar mass decrease 11.86% and 10.34% respectively with the reliabilities of 90% and 95% with the impact angle in -30°~30° and impact velocity in 40~60 km/h.

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    Driver fatigue recognition based on approximated entropy and complexity of steering wheel angle
    LI Zuojin, LI Renjie, LI Shengbo, WANG Wenjun, CHENG Bo
    2016, 07(03):  279-284.  doi:10.3969/j.issn.1674-8484.2016.03.005
    Abstract ( 286 )   PDF (1989KB) ( 1131 )  

    A novel approach was proposed to recognize driver fatigue status under real driving conditions based on approximate-entropy (ApEn) and complexity of steering wheel angle (SWA). This approach first calculated a non-linear ApEn and complexity of SWA in a short time sliding window based on structural theory of
    dynamic time-series data analysis. Then a hard threshold based multi-level fatigue status detection model was designed to process the non-linear feature from first stage, and the pre-diagnosis of fatigue level was outputted from a two-input-two-output fatigue mapping rule based on observed samples. The pre-diagnosed fatigue statuses of the observed sample and its adjacent samples were compared to determine the three-level fatigue status of the observed sample. The experiment was set on real road driving environment. The results show that the approach performs an averaged accuracy of 84.6% for three-level fatigue detection on real road driving test. Therefore, the approach can be especially applied to several industrial applications.

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    Visual accurate positioning for vehicle based on vehicle rear features
    TAN Huachun, ZHOU Yang, LI Keqiang, ZHONG Zhiyu
    2016, 07(03):  285-290.  doi:10.3969/j.issn.1674-8484.2016.03.006
    Abstract ( 266 )   PDF (1412KB) ( 799 )  

    The vehicle detection and positioning of the road ahead is very important in the vehicle anticollision warning system. To achieve accurate positing of vehicle, and contribute to subsequent vehicle distance measurement, the primary vehicle detection was done by using the existing visual vehicle detection method (AdaBoost and aggregate channel feature). Then, filtering false positive results by using vehicle geometry constraints. At last, the vehicle accurate positioning based on the rear feature of the vehicle (the rear shadow and the rear wheel) in the area-of-interest. Compared to the positioning method without geometric constraint, the proposed method reduces the false detection rate of the vehicle by 2.28%, and the mean error of the vehicle location is reduced by 44.58%. Experimental results show that the method can effectively solve the problem of low vehicle position accuracy of traditional vehicle detection method.

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    Comparison of different response between Q3 and THUMS 3YO finite element models under ECE R129 test conditions
    HAN Yong, LU Xiaoping, XIE Jinping, WANG Fang, HUANG Hongwu, MIZUNO Koji
    2016, 07(03):  291-298.  doi:10.3969/j.issn.1674-8484.2016.03.007
    Abstract ( 256 )   PDF (2205KB) ( 594 )  

    The influence of the deference of the 3-year old finite element (FE) model on the evaluating performance of the Child Restraint System (CRS) was analyzed. Q3 dummy FE model and THUMS 3YO Human FE model were used to develop front sled test FE simulations with different types of CRS based on ECE R129 regulation. The kinematic behaviors of the FE models were compared, as well as the injury parameters of neck bend angle, chest deflection and chest resultant acceleration. The results show that in front-impact- shield CRS, Q3 were flipped upward, while THUMS 3YO with a motion of declination. The injury parameters of neck bendingangle, chest deflection and resultant acceleration of the THUMS 3YO were larger than Q3. The study shows that the neck and chest of THUMS 3YO FE model are more flexible and less stiffness than Q3 dummy FE model.This conclusion can be as reference for the future application and development of child dummies.

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      Verification method at component level based on B-pillar crashworthiness evaluation
    DONG Ruiqiang, XIAO Feng
    2016, 07(03):  299-304.  doi:10.3969/j.issn.1674-8484.2016.03.008
    Abstract ( 245 )  

    The crashworthiness verification of components level is an effective method to further shorten the development cycle of vehicle project, but there is no uniform and normative technical standards, resulting in the assessment objects and load cases have significant diversity characteristics. In order to find a set of system verification method of components level, with the vehicle side impact body structure design as an example, the evaluation matrix of components level simulation analysis is established according to the diversity of the component level model, and the crashworthiness evaluation standard of B-pillar is put forward. From
    the same object & different load cases, and the same load case & different objects in two different angles, it is identified that using the load case of quasi static and rigidity flat and the side body or B-pillar model to do the crashworthiness verification of components level by screening for various component level models. And, the B-pillar structure design of the three vehicle are analyzed using B-pillar verification model. The result is consistent with the subjective evaluation result.

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    Automotive Energy Efficiency & Environment Protection
    Optimal Control Plant for Switch-Mode Architecture of a Regenerative Braking System
    Samir SACI, ZHANG Junzhi
    2016, 07(03):  305-312.  doi:10.3969/j.issn.1674-8484.2016.03.009
    Abstract ( 242 )  

    The limited torque capacity of the electric motor (EM) is a major concern for regenerative braking systems (RBS). Therefore, several strategies have been designed to coordinate the electric motor (EM) and hydraulic friction brake (HFB). However, these strategies drastically decrease the amount of energy recovered per braking to ensure braking safety and comfort. An optimal control plant was designed to calculate the duty ratio using the mathematical model of the switch-mode architecture. The design inherited from an analogy of the DC-DC booster used a clutch, a torsion spring and a brake actuator to couple the vehicle and the EM. Like for the DC-DC booster, a variating duty ratio was used to modulate the braking torque while optimizing the energy recovered. The model was built in Matlab/Simulink with the algorithm being testified by simulation. The results show a more stable output torque while conserving high regeneration performance.

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    Degradation mechanism of lithium-ion power battery with LMO + NMC blended positive electrode
    LIU Yulong, LOU Zhongliang, SONG Shaoling, WU Ke, WU Ningning, HUANG Jun,ZHANG Jianbo, LIAW Bor yann
    2016, 07(03):  313-321.  doi:10.3969/j.issn.1674-8484.2016.03.010
    Abstract ( 301 )   PDF (2633KB) ( 1098 )  

    The capacity degradation patterns and mechanisms of a cell comprising graphite negative electrodes and {LiMn2O4 (LMO) + LiNi1/3Mn1/3Co1/3O2 (NMC)} blended positive electrodes were investigated and analyzed. The contributions of positive and negative electrodes to the full cell degradation were distinguished by
    measuring the charge/discharge curves, direct current resistance and electrochemical impedance spectroscopy, via embedded lithium metal reference electrode, as a function of cycle number during cycle aging. The results show that 1) In the blended positive electrodes, the lithiation of NMC was hindered by the progressive loss of lithium inventory as well as the growing graphite impedance. Gradually, LMO became the predominant capacity contributor in the blended positive electrodes in the later stage of cycle aging; 2) During cycle aging, the cell capacity faded along with the impedance increase largely at the negative electrode. These results provide evidence for improving the cycling performance of graphite/{LMO + NMC} cells.

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    Energy Recovery System for an Electro-Hydraulic Variable Valve Actuation System
    ZHANG Jian, HUANG Yanjun, HUANG Chao, Amir KHAJEPOUR
    2016, 07(03):  322-329.  doi:10.3969/j.issn.1674-8484.2016.03.011
    Abstract ( 286 )   PDF (2697KB) ( 599 )  

    The electro-hydraulic variable valve actuation (VVA) system ensures variable valve timing and lift, and expends a lot of energy. To improve the energy efficiency of VVA, this paper introduces an energy recovery system (ERS). An accumulator was used to store the surplus, otherwise wasted energy of the discharged oil from the cylinder, so the accumulated pressure of this accumulator was guaranteed the lower energy consumption of the main pump. The valve timing and lift was optimized in GT-power model to achieve the minimum Basic Specific Fuel Consumption (BSFC) of the engine with this VVA system. The results show that the addition of ERS adjusts the timing and lift of the valve flexibly and decreases the VVA energy consumption with a 7% - 11% of engine power increasing and a 6% - 9% of economy increasing.

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    Experimental study on the influence of polyoxymethylene dimethyl ethers (PODE) on ultrafine particle emission of a compression ignition engine
    ZHANG Wugao, WEI Xiaodong, LIN Da, ZHU Yijia
    2016, 07(03):  330-336.  doi:10.3969/j.issn.1674-8484.2016.03.012
    Abstract ( 175 )   PDF (2351KB) ( 832 )  

    Experimental study was done on a turbocharged four-cylinder compression ignition engine fueled with diesel, PODE and diesel/PODE blended-fuel in order to reduce the particle material emission of compression ignition engines. Scanning mobility particle sizer (SMPS) was used to measure the particle size distribution. The test results showed that the particle emission of PODE engine was concentrated on the small diameter scale of less than 30 nm, whereas the diesel engine was mainly between 10 nm and 200 nm. Both ultrafine particle emission and total particle volume of blended-fuel engine was obvious decreased compared
    with original diesel engine at a proper blending ratio. At fixed engine speed, the number concentration of particle emission increased with the increase of engine load, while the specific number concentration decreased. On the other hand, the specific number concentration of particulate became more with the increase of engine speed under the same engine load.

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