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  • 2017, Vol. 08 No. 03 Published on:28 September 2017 Previous issue    Next issue
    Progress & Prospects
    Progress of emission control standards for light-duty vehicles in China
    BAO Xiaofeng, LYU Meng, ZHU Rencheng
    2017, 08(03):  213-225.  doi:10.3969/j.issn.1674-8484.2017.03.001
    Abstract ( 395 )   PDF (2110KB) ( 954 )  

    Elevating standards for vehicle emissions is an effective approach to control vehicular emissions and improve air quality. Light-duty vehicles are the major contributors of HC and CO emissions for its large proportion in vehicle population, and controlling the light-duty vehicular emissions has always been the
    emphasis of air pollution prevention in China. The progress of the emission control standards in Chinese Mainland, Japan and developed countries in Europe and America were firstly introduced. And the features of China 6 emission standards were analysed, namely continuation of European standards, import of World Light-Duty Test Cycle, reference of American standards. Then the control method of light-duty vehicular emissions was proposed based on the analysis of the emission control technology, improvement of automotive fuels and the supervision of on-board diagnostics (OBD). The future development of emissions standards and emission control technologies were prospected.


     

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    Particulate Matter Emissions from Gasoline Direct Injection Engines: Research Review
    FANG Tiegang, WANG Libing, WANG Zhi
    2017, 08(03):  226-238.  doi:10.3969/j.issn.1674-8484.2017.03.002
    Abstract ( 264 )   PDF (1813KB) ( 645 )  

    Gasoline direct injection (GDI) engines produce more particulate matter (PM) emissions compared with port fuel injection (PFI) engines. Facing the upcoming stringent regulations in Europe and China, much attention has been paid to reduce the PM emissions of GDI engines. This article provided a brief overview of the research works on particulate matter emissions of gasoline engines, especially for GDI engines to reduce the particulate matter emission, and to meet the requirement of the upcoming stringent regulation. First, discussed the formation of particulate matter in gasoline engines and the difference between GDI and PFI engines. Then,  analysed the mechanisms leading to the GDI engines’ higher PM emission. Moreover, summarized some recent research and development trends of studies on particulate emissions of GDI engines. At last, discussed different approaches to reduce the particle emissions of GDI engines. The results show that gasoline particle filter (GPF) has good potential to be a suitable and cost effective solution, even when considering the fuel consumption and carbon dioxide penalties.

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    Automotive Safety
    Neck injury comparison between BioRID II and THUMS model in whiplash test
    HU Yuanzhi,HU Yuanyuan,JIANG Chengyue, LIU Xi,LIAO Gaojian
    2017, 08(03):  239-245.  doi:10.3969/j.issn.1674-8484.2017.03.003
    Abstract ( 400 )   PDF (1454KB) ( 2091 )  

    Neck-injuries were investigated in whiplash test by two different occupant models (the THUMS (total human model for safety) and BioRID II model) to design a better anti-whiplash seat with occupant-neck protection. A seat finite element model was established to simulate whiplash test according to the China New
    Car Assessment Programme (C-NCAP) (2015 Ed) evaluation procedures and principles of whiplash test score. The dynamic responses and neck-injuries were compared for the two models. The results show that the THUMS model has better biofidelity with larger neck injury index (NIC), neck shear force, and the torque and tension on neck than the BioRID II model. These will provide valuable references to improve biological fidelity of the BioRID II model.

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    Optimizational design for 40% offset vehicle frontal crash based on a modified EGO algorithm
    SONG Zhengchao, ZHANG Siliang
    2017, 08(03):  246-251.  doi:10.3969/j.issn.1674-8484.2017.03.004
    Abstract ( 338 )   PDF (1189KB) ( 575 )  

    An optimizational design was investigated at vehicle frontal crash cases for a multi-purpose vehicle (MPV) at 40% offset frontal crash to improve the optimization accuracy and efficiency. A modified Efficient Global Optimization (EGO) algorithm was built based on Kriging model considering the improved effect of
    sequence samples of target response and constraints with a new established sequential sampling process at constraint conditions of intrusion and deformation in vehicle crashes. The results show that using the proposed modified EGO algorithm has a mininal sample number of 112 and an error of less than 8.42% with the target acceleration reducing from 28.48 g to 26.77 g in the case of crash, compared with the algorithm without considering sequential sampling, Jones classical EGO sequential sampling algorithm and Schonlau constraint EGO sequential sampling algorithm; while all the other constrained crash performances meet the requirements with reduced mass of 2.89 kg. Therefore, the accuracy and efficiency of the method are verified.

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    Light-mass design of bumper beam system based on multiple modes
    ZHANG Junyuan, LIU Qian, ZHANG Le
    2017, 08(03):  252-260.  doi:10.3969/j.issn.1674-8484.2017.03.005
    Abstract ( 216 )   PDF (2173KB) ( 753 )  

    The light-mass design was performed for front bumper and crash box in the front bumper assembly, which are the important components that influence automotive performance during front impact. The front bumper assembly was decoupled under the automotive collision condition according to the deformation process, the energy absorption characteristics and the transmission relationship of section force between different components of the front bumper assembly. The independent evaluation mode of the front bumper assembly was established. The light-mass design was performed by changing cross-section shapes and materials of structures  based on the independent evaluation mode. The light-mass solution was integrated with automotive, simulated by Ls-Dyna software and compared the performance. The results show that the scheme achieves a 30% lightmass effect with optimizing the collision waveform, the intrusion volume and the average structural force. Therefore, the light-mass design scheme of the front bumper assembly based on the independent evaluation mode is feasible.

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    Dummy performance comparative analysis based on WorldSID 50th dummy and ES-2 dummy
    ZHOU Huifeng, LI Bihao, WANG Dazhi
    2017, 08(03):  261-267.  doi:10.3969/j.issn.1674-8484.2017.03.006
    Abstract ( 173 )   PDF (1203KB) ( 1476 )  

    The difference between WorldSID 50th dummy and ES-2 dummy was studied deeply to clarify the response of WorldSID 50th dummy in vehicle side impact load case. By extending pendulum impact calibration method, the evaluation index regularity and the response character of dummy were investigated of the two
    dummy’s chest, abdomen and pelvis in different impact velocity so that the bearing capability of different part for different dummy was clarified. The result shows that the bearing capability of WorldSID 50th dummy’s chest is slightly better than that of ES-2 dummy, but the abdomen and pelvis of WorldSID 50th dummy has much better bearing capability than those of ES-2 dummy in same load case, which lay the good foundation for clarifying WorldSID 50th dummy response completely in vehicle side impact load case.

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    Automotive Energy Efficiency & Environment Protection
    Simulation of Hydrocarbon Injection used for Catalyzed Diesel Particulate Filter during Active Regeneration Process
    ABDALLA Aniseh, WANG Guoyang, ZHANG Jun, SHUAI Shijin
    2017, 08(03):  268-278.  doi:10.3969/j.issn.1674-8484.2017.03.007
    Abstract ( 236 )   PDF (2276KB) ( 594 )  

    Diesel oxidation catalyst (DOC) upstream of catalyzed diesel particulate filter (CDPF) with additional diesel injection (hydrocarbon injection, HCI) were used to control the particulate matter (PM) emissions to meet stringent emission regulations for heavy-duty diesel vehicles. This study optimized the location of injector
    upstream of DOC by evaluating the uniformity of HC distribution on the entrance of DOC. An HCI was used in active regeneration to enhance the exothermic heat of CDPF to initiate the soot regeneration. Numerical analysis was established for the combination of after-treatment technology DOC-CDPF, and a spray model for HCI was implemented into a commercial CFD code named AVL FIRE. Different locations and orientations of the injector were tested. The results show that injector location has a significant effect on the optimal mixing between the exhaust gas and injected hydrocarbon (HC). Optimum injector location is the injector located farthest from DOC, while the long distance between injector and DOC allows enough time for injected HC to form secondary droplets, as it mixes well with exhaust gas downstream. Using HCI upstream of DOC causes the exhaust gas temperature to increase and reaches 550 ℃ at the entrance of CDPF, which is enough to initiate active DPF regeneration.

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    Development of an inline 3-cylinder 1.0-L turbocharged direct injection engine
    ZHANG Shemin, DENG Limei, JIANG Nan, et al
    2017, 08(03):  279-286.  doi:10.3969/j.issn.1674-8484.2017.03.008
    Abstract ( 248 )   PDF (2505KB) ( 834 )  

    A 1.0 liter 3-cylinder turbocharged gasoline direct injection (TGDI) engine was designed and developed by Dongfeng Motor Corporation. In design and development, computational fluid dynamics (CFD) simulation, port flow test, transparent engine investigation and a series of advanced technologies were used
    to optimize the combustion system to improve the comprehensive performances. An efficient and low inertia turbocharger was selected, to ensure performance output and transient responsiveness. Effective technical measures including friction reducing, thermal management, variable oil pump and dual variable valve timing (DVVT) were applied to achieve the good fuel economy. Engine structure design, mass balancing strategy and mounting system optimization were made to achieve excellent noise vibration and harshness (NVH) performance. Bench tests and vehicle carrying tests were done. The results show that benefited from the modular design concept, the engine size is minimized with the advantages for packaging, especially for hybrid vehicles, therefore meeting the design goals of the engine performances.

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    State estimation and lateral stability control for electric vehicles based on EKF and MPC algorithm
    School of Mechatronics & Vehicle Engineering, Chongqing Jiaotong University, Chongqing 400074, China
    2017, 08(03):  287-295.  doi:10.3969/j.issn.1674-8484.2017.03.009
    Abstract ( 232 )   PDF (2476KB) ( 1090 )  

    The model predictive control (MPC) algorithm was used to establish the predictive control model of vehicle lateral stability to estimate the electric vehicle state accurately and improve the safety performance of vehicle, based on two degrees of freedom model. The vehicle sideslip angle, yaw angular and tire slip ratio were selected as state variables and the four-wheel torque distribution was treated as control variables. Considering the driver's operation load and the smooth of steering and driving/braking operations, the cost function of model was built. The extended Kalman filtering (EKF) estimator was designed to estimate and evaluate the current state of the vehicle. And the rolling horizon optimization was solved using Quadratic Program (QP) algorithm to obtain the optimal torque of the four wheels. The co-simulation platform of Simulink and Carsim was constructed and simulated under the high and low attached road surface respectively on the premise that the steering wheel was sinusoidal input. The results show that the MPC medel can effectively maintain the vehicle's lateral stability.

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    Experimental study on influence of physical properties of lubricating oils on particle emissions of diesel engine
    ZHANG Wugao, WANG Zhiyu, TIAN Qiang, GAO Shen
    2017, 08(03):  296-392.  doi:10.3969/j.issn.1674-8484.2017.03.010
    Abstract ( 177 )   PDF (1210KB) ( 709 )  

    The effect of lubricating oils on diesel particle emissions was investigated by the experiments in a production engine D19TCI produced by Kunming Yunnei Power mounted on a bench test dynamometer with six different lubricating oils. The effect of evaporation loss rate, lubricant temperature and engine load were
    analyzed. The results show that low ash lube causes an outstanding decrease on total particle emissions, oils with low rate of evaporation loss can cut down the lube-level particles (over 300 nm) emission by 56%. Hydrofining oil reduces exhaust particle number concentration more significantly than base oil ⅡCI4 by
    8.7% - 20.4%. Synthetic oil PAO has the best particle emission reduction performance at high load. Lube-level particle emissions decline with a lower lubricant temperature at low load, and lube-level particle emissions increase at heavy load while total particle emissions decrease by 57.9%.

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    Air conditioning control multi-stage heating system for new energy vehicle
    DING Peng, WANG Zhong, GE Ruhai, WANG Ying, LI Qinglian
    2017, 08(03):  303-309.  doi:10.3969/j.issn.1674-8484.2017.03.011
    Abstract ( 242 )   PDF (1666KB) ( 842 )  

    The power, comfort and mileage of electric bus are affected by the performance of warm air conditioners. A kind of warm air conditioning system based on multi-stage heating and co-existence control was designed to provide integrated management for lithium battery cooling water, motor cooling water waste heat and positive temperature coefficient (PTC) heating. The system of air conditioning was heated between −25℃ and 25 ℃ by multi-stage to different temperatures, and the heat load of air−conditioned room of electric bus was analyzed. The mathematical model of the air conditioning system was established, and the fuzzy neural network algorithm was used to control the heat load of the air−conditioned room. The results show that the air conditioning system works well and achieves the expected affects (22.1-27.4 ℃ ), which satisfies the human body's thermal comfort evaluation index.

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    Combustion characteristic of a downsized turbocharged compressed natural gas engine
    LI Weixin, YANG Chen, YIN Jiandong, SHEN Yuan, WANG Ruiping
    2017, 08(03):  310-316.  doi:10.3969/j.issn.1674-8484.2017.003.012
    Abstract ( 190 )   PDF (1781KB) ( 671 )  

    A turbocharged spark-ignition engine with port fuel injection (PFI) was developed suing compressed natural gas (CNG) based on a secondary development for a downsizing gasoline engine to reduce both vehicle tailpipe CO2 emissions and other exhaust gas emissions without compromising driving performance. This paper quantified the advantage of fuel performance characteristics of the downsized CNG engine with reduced knock sensitivity, optimized compression ratio, and improved combustion efficiency. While peak cylinder pressure was controlled below 12 MPa, peak torque 180 Nm, same level as gasoline variant, was realized from 3 000 r/min. With adapted compression ratio for CNG operation, effective combustion efficiency is over 38%, which is even higher than turbocharged gasoline direct injection (TGDI) version. Therefore, compared to gasoline application, operation with CNG will lead to 24.2% of CO2 emission reduction as well as 46.4% of mileage-specific fuel cost saving.

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    Experimental study on rapid aging test method of standard bench cycle (SBC) for three way catalytic converter
    CHENG Jiankang, LIU Xiaofang, SHUAI Shijin, XIAO Hongjun, LIN Xihe, ZHUANG Min
    2017, 08(03):  317-322.  doi:10.3969/j.issn.1674-8484.2017.03.013
    Abstract ( 188 )   PDF (1442KB) ( 894 )  

    It was explored how to determine the engine conditions that meet the control requirements of temperatures, air fuel ratios and so on in the standard of GB18352.6-2016 using an experimental engine. The  experimental scheme meeting standard bench cycle (SBC) was proposed, based on the investigation to the SBC cycle used in the rapid aging of the catalytic converter. Through the experiments carried out in the steady state catalytic converter temperature field, the influence of different factors on the temperature of catalyst was studied, such as the air-fuel ratio, ignition advance angle, air injection and etc. The results show that the working mode of the catalytic converter prototype that satisfies the temperature of 800 ℃ distributes in the strip area of 2 000 r/min high load to 3 800 r/min low load. Compared with the ignition time, air-fuel ratio and air injection affect the converter temperature more obviously. Different cycle options can be selected through cyclic consistency, aging time, and transition time.

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