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• 2012, Vol. 3 No. 2
  Published on:18 June 2012 Previous issue    Next issue
  Progress & Prospects

  Key technologies and fundamental academic issues for traction battery systems

  ZHANG Jianbo, LU Languang, LI Zhe

  2012, 3(2):  87-104.  doi:10.3969/j.issn.1674-8484.2012.02.001

  Abstract ( 3151 )   PDF (2451KB) ( 8269 )  

  The limitation of traction battery systems in performance, cost, life, and safety constitutes the bottleneck for
  the diffusion of electric vehicles. This paper analyzes dozens of electric vehicles in the phase of R & D and several major
  commercialized electric vehicles, identifies and reviews four key technologies for the traction battery system, the assembly
  of cells into the battery, thermal management, electric energy management, and safety. Underlying these key technologies,
  two fundamental academic issues are specified: 1) the generation, transfer, and removal of heat in the stacked composite
  system comprising cells and heat conduction plates/flow fields; 2) the modeling, identification, and control of the battery
  system comprising a multitude of non-linear, time-varying cells connected in parallel and series. Further development
  tendency for traction battery systems are viewed, such as the smart cell and the integration with the grid and internet.

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  Recent Progress in HCCI Combustion for a Practical Usage as a Gasoline Engine

  Yasuo MORIYOSHI, Tatsuya KUBOYAMA

  2012, 3(2):  105-115.  doi:10.3969/j.issn.1674-8484.2012.02.002

  Abstract ( 2636 )   PDF (3653KB) ( 3089 )  

  Internal combustion engines are widely used in cars, trucks and buses. Among them, the spark
  ignition engine with gasoline fuel is mainly employed for passenger cars. As the number of cars is extremely
  increasing in the world, thermal efficiency in gasoline engines must be improved urgently with less expensive
  cost-up. The homogeneous charge compression ignition (HCCI) combustion system has been attracted as
  the promising and alternative combustion system to the spark ignition. Although many researchers have been
  conducted to this system to solve the challenging issues, the practical usage is still unclear. This review paper
  covers the technical methods examined so far, including the authors' idea of blow-down super-charged HCCI, to
  introduce interesting ideas helping researchers who like to find a new way or to start investigating on the system,
  leading to accelerate the practical usage of HCCI systems for the energy saving in the world.

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  Automotive Safety

  Developing Methodology for Design and Assessment of
  Active and Integrated Safety Systemsfor Automobiles

  Martijn TIDEMAN, Thijs VERSTEEGH, Roy BOURS, Xuejun LIU

  2012, 3(2):  116-122.  doi:10.3969/j.issn.1674-8484.2012.02.003

  Abstract ( 2594 )   PDF (6896KB) ( 2687 )  

  Developing active and integrated safety systems for automobiles is a complicated and timeconsuming
  activity. TNO (The Netherlands Organization for Applied Scientific Research) has created a new
  methodology for design and assessment of active and integrated safety systems to make the development
  process more effective and efficient. The main tools used within the method are PreScan, VeHIL and MADYMO.
  The method is based on seamless integration of simulation tools and test facilities to convert real world accident
  statistics and/or user requirements to a system design and, from there, to a prediction of real-world accident
  rates and injury levels. Experimental results are used to validate the simulation model. The validated simulation
  model is then used to design and test the system to predict the system’s real world effects, and to define the set
  of experiment needed for final verification of the system. Concrete examples demonstrate how these tools can
  together be applied in the development process of active and integrated safety systems.

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  Relativity between whiplash test assessment systems of different countries based on sled tests

  YANG Yunsheng, ZHANG Xiaolong*, LOU Lei

  2012, 3(2):  123-128.  doi:10.3969/j.issn.1674-8484.2012.02.004

  Abstract ( 2183 )   PDF (3177KB) ( 2373 )  

  Abstract: Vehicle low speed rear-end impact is a familiar traffic accident type. In order to prevent the
  occupants’ cervical whiplash injury in this accident, different countries are promoting the development of passive
  safety technologies. This paper analyses similarities and differences of the test methods, scoring methods and
  assessment systems of Chinese, European, Japanese and American whiplash test programs. The whiplash
  test is added to China New Car Assessment Program (C-NACP) of 2012 new version which is different from
  European New Car Assessment Program (Euro-NCAP), Japanese New Car Assessment Program（J-NCAP） and
  that of the American Insurance Institute for Highway Safety (IIHS). This paper scores the same test data based
  on the above scoring methods and assessment systems, transforms the scoring results into the 3 points system
  and analyses the results. The results show that although various assessment systems have differences, but
  assessment results have high consistency. The C-NCAP assessment score is higher than the others.

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  Case analysis of US NHTSA 2010 version of new car assessment program

  YUE Guohui, CHEN Xianling, ZHANG Kai

  2012, 3(2):  129-135.  doi:10.3969/j.issn.1674-8484.2012.02.005

  Abstract ( 2058 )   PDF (3056KB) ( 2093 )  

  The US National Highway Traffic Safety Administration (NHTSA) released the 2010 version of New
  Car Assessment Program (NCAP) in 2008, which has been used since 2011. This paper analyzes the new
  NHTSA-NCAP to provide technical supports and references for vehicle models of Great Wall Motor Co., Ltd or
  other companies who want to enter the U.S. vehicle market. The result s show that major changes take place
  in increasing new testing projects, applying new test dummies, optimizing associated injury criteria, assessing
  star rating, and so on. A model which has passed the 2011 NHTSA-NCAP star rating was used as an example
  to assign its star rating according to the analytical content, and was then compared to the results posted on the
  NHTSA official website to validate the analytical content’s correctness. The results show that more attention
  should be paid to the vehicle’s rollover resistance performance.

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  Simulation of driving stability of a tractor semi-trailer in cross-wind

  ZHANG Yipeng, DING Nenggen*

  2012, 3(2):  136-141.  doi:10.3969/j.issn.1674-8484.2012.02.006

  Abstract ( 2186 )   PDF (2283KB) ( 2035 )  

  A vehicle dynamics model and a cross-wind model were constructed using TruckSim software to
  study the stability of a tractor semi-trailer in cross-wind. Digital simulations were carried out at different wind
  heading angles, wind speeds and vehicle speeds with step steering input to analyze different vehicle responses
  of the roll angle, the yaw rate and the hitch angle and then to obtain the critical vehicle speed and critical wind
  speed for the tractor semi-trailer with stability driving. The trailer turns over first when the wind speed is more
  than the critical value. The tractor semi-trailer turns to be drifting, rollover and unstable seriously when the
  vehicle speed is larger than the critical value. The analyses show that the effect on the tractor semi-trailer with
  step steering in a counter direction cross-wind is stronger than those in a positive direction cross-wind. The
  results can provide stability analysis references for tractor semi-trailers in cross-wind.

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  Analysis of Euro-NCAP pedestrian protection testing protocols (v5.3.1 and v6.0)

  LIU Yang, SUN Xiaoguang, YANG Zhanjun, CHEN Xianling, SHI Yutao*, YANG Jinsong

  2012, 3(2):  142-150.  doi:10.3969/j.issn.1674-8484.2012.02.007

  Abstract ( 2426 )   PDF (4663KB) ( 2472 )  

  European New Car Assessment Program (Euro-NCAP) is most influential for new car assessment.
  Euro-NCAP is constituted by non-government consumer group that will select well sold vehicles in the European
  market to run safety performance test, and then publish the result to people for reference. This paper analyzes
  and compares Euro-NCAP pedestrian protection testing protocols (v5.3.1and v6.0) to make China vehicle
  manufacturers obtain better score when participating in the Euro NCAP test. The differences between v5.3.1
  and v6.0 of Euro NCAP pedestrian protection testing protocols were comparatively analyzed including the grid
  point, correction factor, HIC (head injury criterion) tolerance, and principle of assessment to summarize advice
  to supply reference to China’s vehicle manufacturers. China vehicle manufacturers should have CAE (Computer
  Aided Engineering) simulation capacity and pedestrian protection testing ability or else their vehicle development
  will be influenced.

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  Automotive Energy Efficiency & Environment Protection

  Safety control strategy of large format Li-ion batteries and test verification

  2012, 3(2):  151-157.  doi:10.3969/j.issn.1674-8484.2012.02.008

  Abstract ( 2313 )   PDF (3851KB) ( 3318 )  

  Whether the lithium-ion battery can enter the EV, HEV and PHEV markets depends on its safety, and the
  thermal runaway control is the most critical challenges. This paper discusses the field failure abuse thermal runaway
  of large format lithium ion batteries in vehicular applications, focusing on the evolution of the insight process of thermal
  runaway. In terms of the positive electrode, negative electrode, electrolyte, separator and current collector, the impacts on
  safety of the key materials are reviewed, with the battery safety control strategy proposed. The LiNi1/3Co1/3Mn1/3O2 based
  battery with nominal capacity of 12 Ah was developed with modified key materials with energy density of 160 Wh/kg and
  power density of 1.25 kW/kg. Tests were carried out for 0.5 C rate / 20 V overcharge and fully charged state (4.2 V) hot-box
  at 150 °C for 4 h. The results show that the batteries are safe, the effectiveness of the proposed safety control strategy is
  verified, and the self-discharge and chemical stability of the safe batteries arebetter than those of traditional batteries.

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  Experiments and modeling of anisotropic thermal conductivity of lithium-ion batteries

  FENG Xuning, LI Jianjun, WANG Li, GAO Jian, HE Xiangming, OUYANG Minggao

  2012, 3(2):  158-164.  doi:10.3969/j.issn.1674-8484.2012.02.009

  Abstract ( 1852 )   PDF (2448KB) ( 3110 )  

  Since thermal property affects the performance, safety and longevity of the lithium-ion battery,
  specific research is necessary. This paper conducts thermal modeling of a lithium-ion battery which is
  simplified as a cuboid with anisotropic thermal conductivity. Experiments were made to get the anisotropic
  thermal conductivity. Supposing that the thermal conductivity and the convection coefficient are unknown,
  based on model simulation, relationship was found between the isotherms of characteristic points and the
  modeling thermal parameters. By analyzing the relationship, a graphic method was proposed named three lines
  concurrent to determine the thermal parameters in modeling. Using the results of the graphic method, simulation
  results matches well with the experimental data. The results verify that the parallel-direction thermal conductivity
  is higher than the perpendicular-direction thermal conductivity in punch type lithium-ion batteries.

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  Automotive Energy Efficiency & Environment Protection

  Model predictive control for parallel hybrid electric vehicles with potential real-time capability

  ZENG Xiangrui, HUANG Kaisheng*, MENG Fanbo

  2012, 3(2):  165-172.  doi:10.3969/j.issn.1674-8484.2012.02.010

  Abstract ( 1999 )   PDF (2994KB) ( 2724 )  

  The control strategy of the hybrid electric vehicle (HEV) plays an important role in the fuel economy
  and emission performance. This paper presents a model predictive control (MPC) torque-split strategy for
  parallel hybrid electric vehicle powertrains based on a simplified first-order diesel engine transient model. A
  torque request prediction method based on the driver’s accelerator pedal is presented for the MPC strategy.
  With consideration of the motor’s compensation to the engine’s dynamic torque response delay, the optimization
  constraints and objectives were designed with the non-linear HEV torque-split problem simplified to a linear
  programming problem. In the simulation the MPC torque-split strategy, which is potentially real-time-capable,
  operates in less than 150 ms. Simulation results show that the MPC strategy can improve the fuel economy by
  2.5% compared with a rule-based strategy.

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  Experiment of a gasoline engine fueled with gasoline-DMF#br# blends and gasoline-alcohol blends

  MA Zhiyan, SHEN Haiqing, WEI Jianqin, XU Cangsu

  2012, 3(2):  173-178.  doi:10.3969/j.issn.1674-8484.2012.02.011

  Abstract ( 2193 )   PDF (2539KB) ( 1663 )  

  In the test conditions without changing the ignition advance angle and the fuel supply system, the
  performance characteristics of gasoline-2,5-dimethylfuran (DMF) blends and gasoline-alcohol blends were
  investigated in a gasoline internal combustion engine using biomass fuel to reduce dependence on oil and impact
  on environment. Tests show that the power performance of gasoline-DMF blends is superior to that of gasolinealcohol
  blends. Compared with using gasoline-DMF blends with DMF mass proportion of 10%, the maximum output
  torque and output power decrease by 5.2% and 11.3% when using the gasoline-alcohol blends with methanol mass
  proportion of 10%; the fuel consumption rate of gasoline-DMF blendsis superior to gasoline-alcohol blends and that
  of blends with DMF mass proportion of 10% is lowest at different rotate speeds. But the energy consumption rate
  of gasoline-DMF blends is larger than that of gasoline-alcohol blends. Traditional legislated emissions of gasoline-
  DMF blendsare less than that of gasoline-alcohol blends as a whole.

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  Influence of biodiesel/diesel blends proportions on emission particle microscopic characteristics of diesel engines

  ZHANG Xiaoyu; MA Zhihao* ; MA Fanhua; XU Bin; WU Jian

  2012, 3(2):  179-183.  doi:10.3969/j.issn.1674-8484.2012.02.012

  Abstract ( 2325 )   PDF (2813KB) ( 1631 )  

  Tests were carried out in an electric controlled high pressure common rail diesel engine to research on
  microscopic characteristics of particle emitted from a diesel engine fueled with biodiesel. A diesel engine fueled with
  different proportions of biodiesel/diesel blends was operated stably at 2 000 r/min and 225 N·m. The fractal dimension
  of the particles emission was calculated according to the Brasil algorithm using high-resolution transmission electron
  microscope (HRTEM). The results show that spherical primary particles of which mean diameter ranged between 26.56
  nm and 28.61 nm consist of the particles exhibiting characteristics of fractal structure generated by the combustion of the
  fuels with biodiesel volume fraction of 0%, 10% and 50%. Mean diameter of primary particles for fuel with volume fraction
  of biodiesel of 100% is 45.57 nm, which is quite different from the other three kinds of fuels. With increasing percentage of
  Pistaciachinensis Bunge seed biodiesel, fractal dimension increases gradually and primary particles become more close
  while mean fringe separation distances decrease and the oxidation activities become lower.

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