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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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  • 2017, Vol. 08 No. 04 Published on:30 December 2017 Previous issue    Next issue
    Progress & Prospects
    Development of transmission technology for energy-saving vehicles and new energy resource vehicle
    XU Xiangyang
    2017, 08(04):  323-332.  doi:10.3969/j.issn.1674-8484.2017.04.001
    Abstract ( 444 )   PDF (1977KB) ( 1287 )  

    Transmission technology is the key of the vehicle powertrain. The development of energy-saving vehicle and new energy resource vehicles posed new challenges to the transmission technology. Based on energy-saving vehicle and new energy resource vehicle technology roadmap, the requirement of the traditional internal combustion vehicles, hybrid vehicle (HEV) and plug-in hybrid vehicle (PHEV), pure electric vehicle (EV) on the transmission system side were proposed, and the development of the transmission industry in Mainland China was also described. The characteristics of different types of automatic transmission was analyzed. The development direction of multi-shift, wide speed ratio, lighting weight, high power density, high efficiency and
    continuous optimization was described. The types of HEV/PHEV configuration schemes and their respective characteristics were introduced. The advantages and disadvantages of typical configuration schemes and the development of HEV/PHEV control technologies were analyzed. Finally, the development of centralized electric drive and distributed electric drive technology was introduced.

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    Challenges and opportunities of smart occupant protection against motor vehicle collision accidents in future traffic environment
    ZHOU Qing, JI Peijun, HUANG Yi, et al
    2017, 08(04):  333-350.  doi:10.3969/j.issn.1674-8484.2017.04.002
    Abstract ( 350 )   PDF (1881KB) ( 1618 )  

    This paper predicts new issues of vehicle collision accidents in the environment of future intelligent traffic, and reviews the trend of smart occupant protection driven by the development of future traffic technology.In the future, connected vehicles and autonomous driving technologies will reduce occurrence rate of motor vehicle collision accidents. In vehicle platoon with high-speed and small following distance, if any small probability incident triggers an accident, large number of severe injuries will result in multiple-vehicle collisions at high-speed. On the positive aspect, future intelligent transportation technologies will achieve more reliable pre-crash sensing. Accurate information of occupant status and pre-crash warning will enable development of smart occupant restraint system that can provide tailored protection for occupants with different sitting postures, statures and biomechanical characteristics, as well as different crash modes and crash severities. Referencing the concept of uniform restraint, current restraint system may be optimized, and new restraint modes may be envisioned and developed for protections from high-speed crash. Such a restraint system will be adaptive and tunable to different situations, and it will only be applied on occupant body when needed, offering safety function without sacrificing comfort and convenience.

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    Automotive Safety
    Distributed H∞ control of automated vehicular platoons with uncertain interaction topologies
    GAO Feng, LIU Bao, LI Keqiang
    2017, 08(04):  351-358.  doi:10.3969/j.issn.1674-8484.2017.04.003
    Abstract ( 173 )   PDF (2331KB) ( 679 )  

    A distributed H∞ control method for automated vehicular platoon interacted by uncertain network topologies was presented to improve the road efficiency and to alleviate the pressure of traffic. Based on the vehicle longitudinal dynamics compensated for by an inverse model, the vehicle node model and its parameter
    range were obtained by process identification. A decoupling method was proposed based on the platoon uncertain model set up to decompose the platoon system through linear transformation and eigenvalue decomposition of topological matrix. A numerical method was given to design and optimized the distributed H∞ controller with linear matrix inequality (LMI) approach, and its robust stability and tracking performance was validated by bench tests. The results show that the distance error and the speed error are less than 1 m and 0.3 m/s respectively with the model errors and environmental disturbances used in tests. The proposed distributed H∞ control strategy can attenuate the disturbances arising from model errors and environmental resistances, and accordingly a fine robust performance of platoon is ensured. 

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    Control algorithm on automotive emergency collision avoidance based on road surface identification
    WEI Minxiang,YAN Mingyue, WANG Yan, et al
    2017, 08(04):  359-366.  doi:10.3969/j.issn.1674-8484.2017.04.004
    Abstract ( 177 )   PDF (2807KB) ( 470 )  

    A control algorithm, which combined the lane changing for collision avoidance under different road conditions with the adaptive cruise control, was established to deal with the dangerous conditions of emergency braking from the preceding vehicle. The scene model of emergency collision avoidance was proposed based on PreScan software, and the recursive least square algorithm was used to discriminate of road surface. The path for collision avoidance was planned based on distinguishable road, and the distance model which met the multivehicles movement constraints for the safety of lane changing was set. The collision avoidance system was used to monitor the motion states of vehicles to control of the vehicle to change lane for collision avoidance. The adaptive cruise control was used to keep a safety distance to avoid the rear collision between the own vehicle and the preceding vehicle in slow lane. The results show that the proposed algorithm was verified to be effective based on the co-simulation of PreScan and Matlab / Simulink, and the vehicle can avoid collision safely on the bituminous and ice-snow road.

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    Parameter sensitivity analysis of vehicle head shape for vehicle-pedestrian accidents
    LI Hua, LI Yuelin, ZOU Tiefang, et al
    2017, 08(04):  367-373.  doi:10.3969/j.issn.1674-8484.2017.04.005
    Abstract ( 198 )   PDF (1380KB) ( 299 )  

    The simulation tests were conducted with the Pc-Crash software based on the measured data of 411 vehicles’ head shape to obtain more information about the influence of the vehicle head shape on the dynamic response of the pedestrian in vehicle-pedestrian accidents. All parameters about the dynamic response of the pedestrian were measured. A exist parameter sensitivity analysis method was adopted to analyze the sensitive of the vehicle head shape. The results show that in the orders of 8 sensitivity parameters used to describe the pedestrian dynamic response, the first is the height between the front windshield bottom and the ground, the second is the length of hood, the last is the height between the bumper bottom and the ground. Combining the velocity analysis, the orders of the sensitivity parameters is velocity, the length of car head, the height of car head. It is clarified that the most sensitivity parameters is the height between the front windshield bottom and the ground among the 8 parameters which have the influences on difference dynamic response. The research is practical meaningful in the fields of accident area, the trace measurement and the design of the vehicle shape.

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    Conducted electromagnetic interference in electric vehicle wireless charging system and its effects on system safety
    GUO Yanjie, WANG Lifang, ZHANG Junzhi, et al
    2017, 08(04):  374-380.  doi:10.3969/j.issn.1674-8484.2017.04.006
    Abstract ( 199 )   PDF (2984KB) ( 663 )  

    The equivalent electromagnetic interference (EMI) sources were analyzed to clarify the conducted electromagnetic interference characteristics in electric vehicle (EV) wireless charging system (WCS) and its effects on system safety. WCS equivalent circuit model was established. Harmonic gains of the conducted EMI
    transfer functions were studied based on the actual parameter values. The experiments were carried out to investigate the conducted EMI characteristics and their effects on system safety under the conditions of system rated state, coil large misalignment, and discontinuous conduction mode (DCM) of the rectifier. The results show that coil large misalignment and rectifier DCM would bring high frequency conducted EMI, and some measures need to be taken for EMI suppression. Meanwhile, the rectifier input inductance should be big enough to avoid conducted EMI brought by rectifier DCM, for the sake of improving system safety.

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    Analysis of two-wheelers kinematics before/during/after vehicle collisions based on video records
    HAN Yong, HE Wei, LI Quan, et al
    2017, 08(04):  381-387.  doi:10.3969/j.issn.1674-8484.2017.04.007
    Abstract ( 182 )   PDF (1652KB) ( 478 )  

    The kinematics of riders was analyzed based on the 200 two-wheelers accident videos which downloaded from Internet to more clarify the accidents characteristics and the kinematics of two-wheelers before/during/after vehicle collisions. The rider’s collision parameters (e.g., accident scenarios, avoidance
    motion, kinematics and trajectory during vehicle impact, and ground contact) were examined. The results show that 60% of vehicles are sedan in these cases, 85% of accidents occur in the crossroad, 80% of accident vehicles are travelling straight ahead and 53.5% of the riders show avoidance motions before collisions. In the ground impact, the most frequency of the landing posture is the head and lower limbs to make the first impact to the ground. The order of riders’ body regions making contact against the ground depends on the landing posture. The research results can provide reference for making the safety countermeasures to reduce the accidents and the injury of the two-wheelers.

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    High voltage safety design and protection based on an electric vehicle collision
    ZHANG Yajun, REN Gaohui, LI Junjie
    2017, 08(04):  388-396.  doi:10.3969/j.issn.1674-8484.2017.04.008
    Abstract ( 184 )   PDF (1997KB) ( 878 )  

    The response mechanism of the geometrical shape, properties and arrangement form under impact load was clarified for the special parts of electric vehicle (EV) such as high voltage battery module and power battery pack to provide reference for electric vehicle design and development. In combination with the results of the collision test of electric vehicle, the probability statistics of collision accident and the typical traffic accident conditions, a high-voltage collision safety protection design scheme was designed based on collision poweroff protection and real-time insulation monitoring. By using computer aided engineering (CAE) simulation calculation, the space layout of high voltage components was optimized to solve more than 90% of medium-speed and low-speed traffic accident problems. The corresponding collision safety boundary under the high speed collision condition was developed, and the response signal of power of protection was extracted. The result shows that double protection, including monitor the insulation resistance of electric vehicle in real time and
    performing power of function by the electric relay, can avoid the failure of electrical safety protection caused by a single factor failure, by which the actual high voltage protection of electric vehicle is realized.

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    Automotive Energy Efficiency & Environment Protection
    Evaluation method of energy consumption index of pure electric vehicle based on minimum limit energy consumption
    LI Xinghu
    2017, 08(04):  397-402.  doi:10.3969/j.issn.1674-8484.2017.04.009
    Abstract ( 155 )   PDF (1312KB) ( 400 )  

    Determining the limit target value of energy efficiency and driving range under ideal conditions is of great significance to the evaluation and improvement of energy consumption of pure electric vehicles. A new evaluation method of advanced energy consumption index was given for pure electric vehicle, with defining
    the concept of four new parameters, such as minimum limit energy consumption, maximum limit driving range, energy efficiency ratio and driving range ratio. In addition, giving a method of determining the four parameters, deduces its formula and calculates values of these parameters under the flat road and the New Europe Driving Cycle (NEDC) test conditions. The results show that the minimum limit energy consumption and the maximum limit driving range represent the minimum energy consumption and the longest drive range under the ideal condition of pure electric vehicle power system without any energy conversion loss. Energy efficiency ratio and driving range ratio are reciprocal, can be used to evaluate the energy conversion efficiency of pure electric vehicles, the value of these two parameter closer 1, the energy conversion efficiency of pure electric vehicle is higher.

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    Development of a new control platform for compression ignition engines
    FANG Cheng, YANG Fuyuan, OUYANG Minggao, et al
    2017, 08(04):  403-411.  doi:10.3969/j.issn.1674-8484.2017.04.010
    Abstract ( 154 )   PDF (2857KB) ( 300 )  

    A new control platform for compression ignition engines was developed to improve the performance of engine control systems and support the research of new combustion modes with gasoline-diesel blended fuel. An integration architecture was introduced based on a new automotive grade multi-core microcontroller
    MPC5746R. Automotive Open System Architecture (AUTOSAR) rules were applied to the basic software and coordination mechanisms between two cores were designed. Engine position detection, injection control and cylinder pressure acquisition were included in the complex drivers. Engine control and combustion control (combustion indexes calculation, combustion mode recognition and feedback combustion control) were integrated into the application software. Verification tests were done on a 1.9 L diesel engine. The results show that it is able to acquire cylinder pressure information, calculate combustion indexes and do the feedback combustion control in real-time applications by using this control platform.

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    Visualization and emission for a GDI engine using double injection at cold start in-cylinder process
    GONG Yanfeng, SONG Zhiping, LI Xian, et al
    2017, 08(04):  412-418.  doi:10.3969/j.issn.1674-8484.2017.04.011
    Abstract ( 159 )   PDF (1959KB) ( 533 )  

    Pollutant emissions for a Gasoline Direct Injection (GDI) engine with double injection at cold start in cylinder process were investigated using a visualization method. The spray and combustion images in an optical single cylinder engine were recorded simultaneously from two directions perpendicular to each other utilizing two high-speed cameras. A combustion analyzer and a micro-soot-sensor were used to analyse combustion stability and soot emission. A CLD500 type fast NOx system and a HFR500 type fast Flame Ionization Detector (FID) system were used to sample nitrogen oxide and hydrocarbon emission. The results show that the main reason for high soot emission caused by impinging more fraction fuel on piston crown and forming oil film under cold start condition using delayed second injection timing. While, advancing second fuel injection improves combustion stability. Increasing first injection fraction decreases the emissions of soot, NOx and HC with a slight negative effect on the combustion stability.

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    Emission tests on real driving passenger cars
    ZHANG Ni, CHEN Rong, LONG Yongsheng
    2017, 08(04):  419-424.  doi:10.3969/j.issn.1674-8484.2017.04.012
    Abstract ( 285 )   PDF (2753KB) ( 396 )  

    Actual vehicle emission tests were carried out according to the Ⅱ type-approval test requirements of Real Driving Emssion (RDE) with an on-sell car to verify whether the selected driving routes can meet the RDE test requirements, while investigating the engine work areas. The results show that the selected route
    can effectively meet the basic requirements of the test (urban-city-highway) with driving pattern satisfying the validation of driving dynamics characteristics. And the emission results from the real route show that Conformity Factor (CF) values, calculating from Worldwide harmonized Light Vehicles test Cycle (WLTC) results, are higher than those given by the regulation. Therefore, the emission regulations need to consider the CF value setting. The engine work area is significantly larger than that in WLTC, thus significantly increasing work of calibration optimization.

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    Developing of hybrid bus by optimizing drivability and fuel economy
    DU Zhiliang, ZHANG Ke, LI Cheng, et al
    2017, 08(04):  425-431.  doi:10.3969/j.issn.1674-8484.2017.04.013
    Abstract ( 161 )   PDF (2503KB) ( 486 )  

    A new method and process for the development and optimization of hybrid bus were built to improve the drivability and fuel economy for a hybrid bus. Based on Chinese typical City Bus Driving Cycle (CCBC) and the city part of adapted world transient vehicle cycle (C-WTVC), the parameters of engine torque and motor
    torque on target hybrid bus were adjusted. After the optimization, the bus’s fuel consumption is reduced greatly (12.8% under the city part of C-WTVC and 23.5% under CCBC) without sacrificing drivability. Therefore, the bus's powertrain efficiency is improved significantly, and the purpose of energy-saving and emission-reduction is realized. This method can also be used to optimize vehicle performance according to customer’s actual road spectrum.

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    Effect of leading edge swept on low specific speed centrifugal compressor performance
    WANG Chenfang, ZHANG Ruidong, ZHUGE Weilin, et al
    2017, 08(04):  432-436.  doi:10.3969/j.issn.1674-8484.2017.04.014
    Abstract ( 193 )   PDF (1515KB) ( 388 )  

    The forward-swept blade flow control method on low specific speed centrifugal compressor was studied to promote the application of vehicle electric supercharger. Three dimensional simulation model of low specific speed centrifugal compressor was established. The performance and the flow mechanism of centrifugal compressor with forward-swept blade was clarified . The results show that the pressure ratio, efficiency and stable working range of the forward-swept angle of 20° and original compressor are of little difference; the leaf tip load and leakage flow of the front part of the forward-swept compressor main blade reduce, while there is no significant improvement of flow condition at back end of the main blade. The distribution of arc angle of the main blade should be optimized of the centrifugal compressor with forward-swept blade to improve the performance.

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