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• 2013, Vol. 4 No. 1
  Published on:25 March 2013 Previous issue    Next issue
  Progress & Prospects

  Energy-saving technologies of the unconventional thermal cycle internal combustion engines

  PEI Pucheng, LU Yong

  2013, 4(1):  1-15.  doi:10.3969/j.issn.1674-8484.2013.01.001

  Abstract ( 1306 )   PDF (1482KB) ( 3022 )  

  Many unconventional thermal cycle internal combustion (IC) engines have been proposed which
  greatly enhance IC engine thermal efficiency. By reviewing some typical energy-saving technologies of the
  unconventional thermal cycle IC engines, two common characteristics are summarized in this paper, charger
  transit between cylinders and steam assistance. By using the technology of the charger transit between
  cylinders, a working cycle of an IC engine can be divided into several cylinders, so the compression ratio can
  be greatly increased, or the over-expansion cycle can be realized, both of which can substantially enhance the
  IC engine thermal efficiency. By using the technology of steam assistance, water can be heated and evaporated
  into steam by injection into hot gas or heat exchanger. The exhaust energy can be recovered when the water
  absorbs the exhaust heat and evaporates to perform further work, which can reduce the exhaust temperature,
  thereby the IC engine thermal efficiency can be enhanced. The technologies of unconventional thermal cycle IC
  engines provide new ideas for the development of the high efficiency IC engine technology.

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  Status and development tendency of the test and assessment#br# technique of the NCAP in different countries

  LIU Yuguang, LIU Zhixin

  2013, 4(1):  16-22.  doi:10.3969/j.issn.1674-8484.2013.01.002

  Abstract ( 1939 )   PDF (1856KB) ( 3488 )  

  Test items and protocols of NCAP (New Car Assessment Program) assessment systems in many
  countries are upgraded accordingly recent years, since road-condition varieties and safety-technology advances
  have been decreasing the discrimination abilities of vehicle safety performance by the initial NCAP systems.
  This paper discusses the history, basic characteristics and the present status of the NCAP of some countries
  and points out the development tendency. Some primary test items such as the frontal impact, side impact,
  rollover test, active safety assistance and overall assessment were analyzed from the angles of the test form,
  impact velocity, dummy positioning and assessment criteria. The results show that active-safety technology
  will be further strengthened, with test items being more comprehensive and rigorous and different NCAP rating
  systems being globalized and normalized in the future. Therefore, manufactures should perform prospective
  study to meet more critical vehicle-safety standards. These results can provide references for upgrading the
  protocols of C-NCAP, the NCAP in China.

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  Automotive Safety

  Effect of rear-seat submarine on dummy injury
  and it’s optimization

  2013, 4(1):  23-26.  doi:10.3969/j.issn.1674-8484.2013.01.003

  Abstract ( 1742 )   PDF (1918KB) ( 2204 )  

  Sled simulation crash tests were made for 100% front rigid barrier crash at 50 km/h according to
  the China New Car Assessment Program (C-NCAP) to develop a type of particular car. The results in the first
  test turn showed that larger deformation and submarining in the rear-seat fixed bracket led to more serious
  injuries on the chest and neck of the rear female dummy with the corresponding C-NCAP test total score of
  0.82. An improved program for the seat fixed bracket restraint system was then developed to overcome the seat
  fixed bracket submarining. Tests showed that the improved program reduces the chest and neck injury of the
  rear female dummy with the corresponding C-NCAP test total score of 1.10. Therefore, the results provide a
  reference for car body optimization.

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  Small-overlap frontal-impact assessments for a vehicle made in China

  Chen Keming, Hu Lijuan, Hu Yanshu

  2013, 4(1):  27-34.  doi:10.3969/j.issn.1674-8484.2013.01.004

  Abstract ( 1796 )   PDF (2674KB) ( 2467 )  

  In small overlap frontal impact, vehicle longitudinal structures, like side rails, fail to absorb impact
  energy that leads to potential risk to occupants. This crash mode has been paid close attention in the world,
  focusing on accident statistical analyses and vehicle crash tests, while no such work can be found in China. This
  paper analyzes the structure performance of a type of vehicle made in China under small overlap frontal impact
  by using CAE and a mature FEA full-vehicle model. A Madymo model calibrated with test results was utilized to
  evaluate the restraint-system performance. An assessment rating was provided based on the test protocol and
  rating guidelines published by IIHS (American Insurance Institute for Highway Safety). The results show that the
  evaluated vehicle only earns MARGINAL ratings in small overlap crash even it earns GOOD ratings in the 40%
  offset impact tests with deformable barrier.

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  Elimination of rib stiffness difference for a Hybrid-Ⅲ dummy
  in frontal crash test

  WANG Hongchuan, SHANG Enyi, ZHAO Yang, WANG Wei, CHEN Xanling, SHI Yutao

  2013, 4(1):  35-40.  doi:10.3969/j.issn.1674-8484.2013.01.005

  Abstract ( 1665 )   PDF (2564KB) ( 1735 )  

  Thorax compressed distortion in frontal crash tests is an important appraisal for vehicle safety
  according to the China New Car Appraise Program (C-NCAP). In current frontal crash dummy tests, different
  rib inconsistent performance may lead to different data of the thorax compression. This paper investigates the
  influence of dummy rib stiffness characteristics and their differences on the chest compression deformation
  through calibrating frontal impact tests for two 50th percentile Hybrid-III male dummies, and revising the
  sensitivity coefficient of chest displacement sensors in the calibrating measurement. The results indicate
  that revising sensitivity coefficient can eliminate the differences caused by rib stiffness characteristics.
  Therefore, this method can improve the test accuracy, strongly supporting the vehicle constraint system
  development.

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  Automotive Energy Efficiency & Environment Protection

  Energy charging and discharging process and the drive circuits
  design of automotive EC actuators

  LI Jianqiu, WANG Jinli, SONG Ziyou, XU Liangfei, YANG Fuyang, OUYANG Minggao

  2013, 4(1):  41-47.  doi:10.3969/j.issn.1674-8484.2013.01.006

  Abstract ( 1249 )   PDF (2573KB) ( 1707 )  

  The injector solenoid valve of a diesel common rail system determines the performance of multiinjections.
  Time delays caused by the inputs /outputs or the network communications strongly influence the
  responsibility and stability of automotive electronic control (EC) systems. This paper analyzes the energizing
  and dis-energizing processes of a typical high speed actuator, and presents an equation to estimate the energy
  release rate. A drive circuit with high voltage was designed, in which different freewheel circuits were disposed
  in different drive stages. The results show that the driver circuit with high voltages obviously shortens the
  energizing and release processes. The current response during the build-up and fall-down of the common-rail
  system injector-valve were shorten to 100-300 μs from original 500-1 000 μs. Therefore, the circuit ensures the
  real-time performance and flexibility of the control system.

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  Review on the research of vehicle windshield heat insulation films

  GAN Shuyi, ZHAO Teng, CHEN Dapeng, ZHANG Lin, ZHOU Jianan

  2013, 4(1):  48-53.  doi:10.3969/j.issn.1674-8484.2013.01.007

  Abstract ( 1834 )   PDF (2138KB) ( 3353 )  

  This paper reviews the research progress of energy-saving and heat-insulation films of vehiclewindshields
  to reduce energy consumption caused by air conditioners. Some typical film design methods were
  introduced, with several experimental results being compared. The films include heat-insulating coating, indiumtin-
  oxide (ITO) coating, mono-silver-base or dule-silver-base low-emissivity (Low-E) coating, transparentinsulation
  coating and sol-gel coating. The results show that the heat-insulating film technology is most widely
  used in the vehicle market, but to obtain both high visible light transmittance and good thermal insulation is
  difficult. Transparent-insulation coating and sol-gel coating are the latest rise of insulation films with low infrared
  light reflectance. Dual-silver based low-E films which can bear thermal bending are the best solution to obtain
  high visible-light transmittance and high infrared reflectance. In the future research focus is to find an excellent
  protection material of Ag-layer to slow down or eliminate the oxidation, agglomeration and diffusion phenomenon
  of Ag at high temperatures.

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  Business patterns of charging or swapping battery service for
  EV taxis in Shenzhen and Hangzhou in China

  CAI Yixin, WANG Hewu, YE Qiang, OUYANG Minggao

  2013, 4(1):  54-60.  doi:10.3969/j.issn.1674-8484.2013.01.008

  Abstract ( 1988 )   PDF (2037KB) ( 3233 )  

  Shenzhen and Hangzhou are two demonstration cities for electric vehicle (EV) applications in China.
  The organization pattern and profitability of EV taxi business were compared between battery-charging service
  in Shenzhen and battery-swapping service in Hangzhou to promote the EV industrialization in China. The
  Shenzhen pattern is quick-charging, vehicle-purchasing, and third-party-operating, while the Hangzhou pattern
  is battery-swapping, vehicle-purchasing without batteries, and battery-renting. The net present value (NPV) and
  the internal rate of return (IRR) of the two patterns were calculated using the value chain analysis method and
  the cash flow calculation method. The results show that the NPV and IRR of the two patterns for business units
  are both negative, indicating a low profitability even with government allowances. Therefore, each pattern needs
  to be improved by developing profitable business and by enlarging local EV market scale.

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  Online estimation of internal temperature fields of lithium-ion
  batteries using a transfer function

  LIU Guangming, OUYANG Minggao*, LU Languang, LI Jiangqiu, LIANG Jinhua, HAN Xuebing

  2013, 4(1):  61-66.  doi: 10.3969/j.issn.1674-8484.2013.01.009

  Abstract ( 1541 )   PDF (2633KB) ( 2377 )  

  The authors found a normal transfer function to calculate online lithium-ion battery temperaturefields
  for estimating battery-performances, which strongly influence electric vehicle (EV) performances. The
  internal-external temperature differences and the heat transfer parameters were measured for a type of lithiumiron
  phosphate-graphite (LFP-G) energy-cell, with a 3-D thermal model then established. The temperature fields
  simulated using a Fluent software under natural convection situation were tested by experiments, with a normal
  transfer function between the internal heat powers and the internal-external temperature-differences then being
  found. The results show that the 3-D model calculation results correspond well with the experimental results
  with a maximum error of 0.7 K, with internal-external temperature-differences having an error of 0.1 K when
  using the transfer function estimation is compared with using the 3-D model. Therefore, the transfer function
  estimation can be used to online estimate the internal temperature field of lithium-ion batteries

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  Modeling of battery management system software in virtual
  simulation environment

  CHEN Ping, PIAO Changhao , DUAN Chongxi, LU Sheng

  2013, 4(1):  67-74.  doi:10.3969/j.issn.1674-8484.2013.01.010

  Abstract ( 1717 )   PDF (2857KB) ( 1734 )  

  Virtual simulation environment was made to test and verify the design of battery management
  system software in the early stage for electric vehicles (EVs). An external module was determined to connect the
  battery management system according to the input/output parameters of battery management system software,
  mainly including state of charge (SOC) estimation, power estimation, fault diagnosis and emergency control. A
  simulation environment model for battery management system software was established in the vehicle working
  environment with the integration of the developed model and the existed models. The results show that using
  the simulation environment model for the battery management system achieves virtual simulation of the battery
  system in the vehicle's working environment, and verifies the effectiveness of the software modules of battery
  management system.

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  Analysis and forming construction of an on-vehicle
  communication protocol Flexray network

  CHENG Chi, SHUAI Zhibing, LI Jianqiu, XU Liangfei, OUYANG Minggao

  2013, 4(1):  75-81.  doi:10.3969/j.issn.1674-8484.2013.01.011

  Abstract ( 1288 )   PDF (2155KB) ( 1530 )  

  The on-vehicle communication protocol Flexray, which can replace the traditional network CAN, can
  adapt to the control-data communication demand of power-train and chassis on automobile due to advantages
  of more nodes, wider band-width, real-time, safety function and time-triggered. This article analyzes the detail
  of the time level and frame construction of the key part of the network, sets up a simple 3-node Flexray network,
  and analyzes the configuration of the protocol parameters including global parameters and local parameters.
  A 3-node Flexray network was built. The results demonstrate the actual communication of the pre-assumed
  signals according to the assumed parameters, therefore, proving the achievability of the constructed network,
  which can be used as a reference to build more complex networks.

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  Influence of penetration speeds on power Li-ion-cell’s
  safety performance

  LIU Shiqiang, WANG Fang, FAN Bin, ZHANG Zhending, PEI Feng

  2013, 4(1):  82-86.  doi:10.3969/j.issn.1674-8484.2013.01.012

  Abstract ( 2080 )   PDF (2753KB) ( 2144 )  

  Power-battery safety performance is a key factor in electric vehicle applications. The inner shortcircuit
  is a root cause of battery safety issues, which is usually simulated by nail-penetration tests in the
  mechanical abuse tests. This paper studies the influence of nail-penetration speeds on the power battery
  safety performance. Two types of lithium iron phosphate (LFP) ion batteries, cylindrical cells and soft-package
  cells, were tested referring the standard of "Lithium-Ion Batteries for Electric Vehicle" for vehicle industries in
  China. The nail-penetration tests were conducted at different nail-penetration speeds for nails, which can bear
  high-temperature, with a diameter of 3 mm. The cell voltage and the surface temperature were monitored and
  analyzed to reflect the influence of different nail speeds on the safety performance. The results show that the
  nail-penetration speeds have low impact on the cylindrical cells compared with that on the soft-package cells.
  As for the soft-package cells, the thermal run away becomes more serious with increasing nail speeds.

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  Approximate calculation of electric-vehicle inverter power-loss in
  two control strategies

  ZHU Yuan, LI Gensheng, WU Zhihong, TIAN Guangyu

  2013, 4(1):  87-92.  doi:10.3969/j.issn.1674-8484.2013.01.013

  Abstract ( 1893 )   PDF (2503KB) ( 1766 )  

  An approximation method for calculating inverter power loss was proposed to guide selecting power
  module and design heat sink with higher efficiency of permanent magnet synchronous motors for space vector
  pulse width modulations (SVPWM) which are widely used in the electric vehicle drive system. Power losses in
  different vector sectors were calculated using this method, and then compared according to the characteristics
  and parameters of insulated gate bipolar transistors (IGBTs) for two drive-system control-strategies of
  permanent magnet synchronous motors. For one control strategy, the d-axis armature current is zero (), and the
  other is with the maximum torque per Ampere (MTPA). The results show that the total power loss of the inverter
  under the MTPA control strategy is smaller than that for the other control strategy, thereby resulting in lower
  temperature rise of inverter heat sink.

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