Journal of Chongqing Jiaotong University(Natural Science)

Research on Visual Characteristics Law and Complexity Evaluation Method of Diagrammatic Guide Signs

DU Hongji1, XU Yachen1，2, ZHAO Xiaohua1, LI Zhenlong1, HUANG Lihua1

2019, 38(07): 1-6. DOI: 10.3969/j.issn.1674-0696.2019.07.01

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Taking four DGSs (two with high complexity, one with middle complexity and one with low complexity) of Beijing urban expressway with different complexity as examples, a dynamic driving test was carried out by using visual tracking technology and driving simulation technology, aiming to study the influence of DGSs on drivers visual characteristics. Drivers dynamic visual recognition process was analyzed and described. Six visual characteristics were extracted to carry out the repeated measurement variance analysis, including the number of eye hops, the total number of gazes, the number of gazes in the region of interest, the total gaze time, the average gaze residence time and the first gaze point time. The comprehensive evaluation of four DGSs was carried out by the factor analysis method. The results show that compared with low-complexity DGSs, the number of drivers gaze at high-complexity DGSs increases significantly. Over-complicated DGSs will distract drivers attention and have a certain impact on driving safety. High-complexity DGSs make the drivers search process grow and it is difficult to extract the target information. The more complex the DGS is, the lower the visibility of the sign is, and the greater the impact on driving safety is. Meanwhile, the visibility results are consistent with the complexity of the selected DGSs. The proposed quantitative evaluation model of DGS recognition can be used for general evaluation of the complexity of other DGSs.

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Design of Lateral Fuzzy Controller for Self-driving Cars

SHAO Yiming1, CHEN Yawei2

2019, 38(07): 7-13. DOI: 10.3969/j.issn.1674-0696.2019.07.02

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A vehicle lateral fuzzy controller was designed. First of all, a two-degree-of-freedom monorail model was established. Then, considering the nonlinearity and random external disturbance of vehicle lateral control, a vehicle lateral controller was designed, based on the drivers practical experience in actual traffic scene and combined with the theory of fuzzy control. According to the lateral error and yaw angle deviation, the appropriate front wheel rotation angle was deduced and output. Finally, the combined simulation was carried out by Carsim and Simulink. The research shows that the designed lateral fuzzy controller can make the vehicle track the center line of the road smoothly and accurately, and achieves the goal of autonomous driving along the desired trajectory.

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Application of TDOA and AOA Algorithm in Vehicle Access Management

LI Zhigang1,2, LV Jie3, DONG Xiaofei3, WANG Bin3, NIU Xinwei4

2019, 38(07): 14-19. DOI: 10.3969/j.issn.1674-0696.2019.07.03

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In order to promote the development of intelligent management technology for vehicle access, a vehicle access management system based on TDOA and AOA positioning algorithms was proposed. RFID technology was used to obtain vehicle’s identity information and location information in real time. The time difference and relative angle of signal propagation between each base station and the vehicle were substituted into TDOA and AOA positioning algorithms to estimate the location coordinates of each mobile node of the vehicle. Through the change of node coordinates, the vehicle entry and exit situation can be judged, and dynamic management of vehicle access can be realized by combining data transmission, automatic control and other technologies. Through the module development and experiment simulation, the proposed system can be applied to the intelligent judgment and management of vehicle access, which provides a theoretical basis for follow-up research.

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Hysteretic Behavior of Prefabricated Concrete Box Culvert Section Based on Drucker-Prager Cap Model

DU Qing, HAO Jingzhao, QING Longbang

2019, 38(07): 20-25. DOI: 10.3969/j.issn.1674-0696.2019.07.04

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In the analysis of hysteretic behaviour of prefabricated box culvert structure by finite element software ADINA, the calculation was often difficult to converge. The Drucker-Prager Cap model based on Drucker-Prager yield condition, tensile truncation and cap hardening criteria provided in ADINA was easy to converge and fast to calculate in numerical analysis of concrete. It is found that the hysteresis curves calculated by the numerical model based on the Drucker-Prager Cap model are in good agreement with the experimental results, and the simulation results are more accurate. The hysteretic curve and related data of prefabricated box culvert can be obtained by numerical simulation, which can be applied to anti-seismic calculation and design of prefabricated box culvert segment.

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Experimental Study on Dynamic Response of Ballastless Track-Bridge Structure on High Speed Railway

LI Zhiming1,TANG Qianlong2

2019, 38(07): 26-33. DOI: 10.3969/j.issn.1674-0696.2019.07.05

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Taking the three-hole 32.0 m standard span prestressed simply supported box girder of a ballastless track-bridge on Shanghai-Kunming high-speed railway as the research object, a multi-section and multi-structure monitoring system was established to carry out the dynamic response test of the ballastless track-bridge structure, and to study the dynamic response law and the track structure-bridge coordinate deformation characteristics of the ballastless track-bridge structural layers at different driving speeds. The results show that: the vertical vibration acceleration of the beam of the prestressed simply supported box girder increases with the increase of train speed when the traveling speed is 290~350 km/h and reaches the peak at 320~340 km/h. The vertical and lateral accelerations of each stratum structure in the beam show a progressively decreasing trend from top to bottom, and the vibration attenuation is significant. There is no obvious correlation between vertical dynamic displacement of the measured points in the mid-span and 1/4-span of the beam body and the driving speed, and vibration deformation meets the requirements of specifications. The relative dynamic displacement between the track plate and the base plate is much greater than that between the base plate and the deck plate, and the vertical relative dynamic displacement is both greater than the lateral relative dynamic displacement. Under the condition of long-term dynamic cyclic loading and unloading, this kind of relative dynamic displacement may cause large plastic cumulative deformation, which should be paid attention to.

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Risk Assessment of Dismantling Project of Long-Span Cable Stayed Bridges

LI Yang

2019, 38(07): 34-39. DOI: 10.3969/j.issn.1674-0696.2019.07.06

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In order to further study the potential risks of dismantling project of long-span cable-stayed bridges, an appropriate risk assessment method for this type of projects was proposed. The main steps included: identifying risk factors by fishbone diagram method, calculating risk weight by analytic hierarchy process (AHP), and evaluating risk grade by fuzzy comprehensive evaluation. Then, the proposed method was used to evaluate the risk of a long-span cable-stayed bridge project. The results show that the overall risk level of this project is medium, and the four most influential factors are the risk of temporary fixture for cables, the risk of water pollution, the risk of crushing and cutting equipment, and the risk of design and calculation. Finally, the corresponding countermeasures for these four risk factors were proposed.

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Quality of Backlight Illumination Based on Different Visual Ranges

LIANG Bo1，2，CHEN Kai1，HE Shiyong1，2，HUANG Youlin1，3，ZHANG Yi1

2019, 38(07): 40-47. DOI: 10.3969/j.issn.1674-0696.2019.07.07

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The quality of lighting engineering is one of the focuses of the research in the field of tunnel lighting. Considering the differences in the resolving power of different regions of the human retina, the scale model of indoor tunnel was used to divide the measuring point area according to different visual ranges. The target brightness and background brightness at each measuring point were measured, and the STV value was corrected and calculated. The influence of central backlight illumination parameters on STV values in different visual ranges was obtained. The results show that: ① When the backlighting angle is 30°, the STV value both under foveal vision and peripheral vision is the largest; ② As the distance between lights increases, the STV value in the foveal vision first increases and then decreases, while the STV value in the peripheral vision gradually decreases; ③ The high diffuse reflectivity sidewall material slightly lowers the STV value, compared with the tile; ④The visual environment under foveal vision is better than that under peripheral vision, and it plays an important role in improving the visibility level of peripheral vision. The modified model of the visibility of small target was proposed, which provided a new idea for the design and evaluation of tunnel lighting quality.

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Dynamic Load Response Analysis of Heavy Vehicle on Unevenness Pavement

SUN Jishu1, LI Meng1, TIAN Hongbin2

2019, 38(07): 48-53. DOI: 10.3969/j.issn.1674-0696.2019.07.08

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In order to study the vibration response of heavy vehicles on the uneven pavement more accurately, the pavement coupling dynamic model of seven degrees of freedom (1+1+5) of the four-axle heavy vehicle was established, and the proposed model was decomposed and simplified into two DOF and one three DOF vehicle vibration models. And the dynamic load of the vehicle was calculated by programming with the help of MATLAB mathematical calculation software. The results show that: because of the vibration response of vehicle on uneven road surface, the trailer rear wheel of four-axle heavy vehicle produces the greatest dynamic load, and the difference between the front wheel and rear wheel of trailer is small, so the change trend is relatively flat. There are two peaks of vehicle dynamic load with the increase of the wavelength of road roughness. When the wavelength of road roughness increases to a certain extent, the maximum dynamic load approaches the self-weight of the vehicle vibration system, and it can be considered that the road surface tends to be flat. The pavement amplitude has rather a great influence on the dynamic load, and the maximum dynamic load is positively correlated with the amplitude. Overload is the main “killer” affecting the service life of road. In order to avoid further damage of the road and increase the service life, the relevant departments should strictly control the phenomenon of overload of vehicles.

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Low Impact Development in Sponge Expressway Service Area Based on Storm Water Management Model

CHEN Fang1, ZHANG Haoyue2, HU Xiaohong1, LIU Huang1

2019, 38(07): 54-59. DOI: 10.3969/j.issn.1674-0696.2019.07.09

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In order to solve the problem of flood control in expressway service area, the specific content and application condition of various LID (low impact development) facilities were introduced in the perspective of LID theory, based on the overall idea of sponge-type service area. The principle of selecting LID facilities was proposed, and LID facilities were applied to Weilong service area in Chongqing. Under the rainfall scenario with an annual total runoff control rate of 80%, the storm water management model (SWMM) was used to simulate it. The results show that by installing LID facilities such as permeable pavement, green roof, grass swale and sunken lawn, waterlogging in service area can be alleviated, and the hydrological environment can be closer to the site before development. According to the LID concept, the design requirements for rain and flood control in service area were put forward to ensure the normal operation of expressway service area.

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Application of BIM Technology in the Design Phase of Municipal Interchange Project

ZHOU You，CHEN Jianfeng，FAN Yufeng，XIA Shihua

2019, 38(07): 60-65. DOI: 10.3969/j.issn.1674-0696.2019.07.10

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Through the application of BIM technology in the Xiaowan Interchange project, the idea and correct process of the establishment of the whole complex municipal interchange BIM model was combed in detail. And then the technology application of earthwork adjustment, collision detection, visual distance inspection and headroom inspection based on BIM technology were studied. Finally, BIM mapping and VR display were tried. The research shows that the application of BIM technology in the design of municipal interchange can effectively optimize the linear shape, longitudinal section, structure and position of the intersection; and the use of BIM model to carry out statistical review of engineering quantities and three-dimensional mapping can improve the quality of design documents and express the design intention more intuitively.

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Influence of Deep Excavation Construction on the Deformation of Adjacent Railway in Operation

ZHAN Tao1，HU Changming2，QIAN Weifeng3，JIANG Xinchi2

2019, 38(07): 66-71. DOI: 10.3969/j.issn.1674-0696.2019.07.11

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Based on the excavation engineering of Shangshagou Station near the existing railway line on Nanchang Metro Line 3, the whole process of foundation pit excavation was simulated by the finite element software. Meanwhile, the influence of foundation pit excavation on deformation of adjacent railway in operation and the reliability of railway reinforcement schemes were both analyzed. The results show that: during the excavation of foundation pit, the maximum track gauge deviation and horizontal differential settlement of track approach the alarm value, which affects the normal operation of train. After setting drilling piles and sealing up piles with jet grouting, the effect of foundation pit excavation on railway deformation can be effectively reduced, and the reinforcement effect is remarkable. The space effect of the deep excavation is obvious at the pit angle. The setting of the isolation structure makes the spatial effect more complex and causes the displacement mutation easily, which should be paid attention to in future practical projects.

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Experimental Research on the Influence of Water Content on Nonlinear Ultrasound Characteristics of Concrete

ZHENG Dan, LIU Li

2019, 38(07): 72-77. DOI: 10.3969/j.issn.1674-0696.2019.07.12

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Concrete specimens with different water contents were obtained by means of drying method, and nonlinear ultrasonic characteristic test of concrete was carried out. And the influence of moisture content on the harmonic amplitude and ultrasonic nonlinear coefficient in nonlinear ultrasonic testing of concrete was studied. The results show that with the increase of water content, the first and second order amplitudes of concrete ultrasonic spectrum increases; meanwhile, the ultrasonic nonlinear coefficient of the material decreases. When the concrete is filled with free water, the internal micro-crack deformation is inhibited by free water in the pores, and the reduction of deformation can be equivalent to the reduction of concrete damage, resulting in a reduction of the measured ultrasonic nonlinear coefficient. The research results can provide a reference for nondestructive testing of concrete structures in water environment.

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Derivation of 3D Model Formula Based on Stability Calculation of Chenqiangyan Dangerous Rock

WANG Jincai, CHEN Wei

2019, 38(07): 78-82. DOI: 10.3969/j.issn.1674-0696.2019.07.13

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Dangerous rock collapse is the main geological disaster type in the Three Gorges Reservoir area and even in the whole western region, which has such basic characteristics as generality, suddenness, concealment and disaster severity. The conformation of formation mechanism and failure mode of perilous rock is a prerequisite to carry out the effective treatment measures on perilous rock. The formula of three-dimensional model for stability of dangerous rock mass was deduced, which provided a more practical three-dimensional model for stability calculation of dangerous rock mass and provided a basis for the design of harnessing engineering. The stability analysis of dangerous rock is complex and difficult. It is more reasonable to use three-dimensional model to calculate and control dangerous rock mass than conventional two-dimensional model.

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Geo-hazard Risk Assessment in Shijiba Town at Longnan Area in Gansu Province

ZHANG Chao1，TIAN Yuntao1，ZHANG Yufei2

2019, 38(07): 83-89. DOI: 10.3969/j.issn.1674-0696.2019.07.14

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According to the latest investigation and cataloguing data of geological hazards in Shijiba township of Baishuijiang River Basin in Longnan area, Gansu province, and on the basis of the analysis of the geological environment background and the characteristics of the development and distribution of geological hazards in the study area, the influence of disaster-causing factors on the development and distribution of geological hazards was analyzed comprehensively by using Arcgis 10.2 software platform. The disaster-causing factors included such as topography and geomorphy, geological structure, engineering geological rock formation, slope structure type, river erosion, vegetation cover, rainfall, earthquake and human engineering activities. By using information quantity method, the geo-hazard susceptibility and geo-hazard risk were assessed and zoned successfully. The method of combining information quantity method with qualitative evaluation method was used to realize the division of the susceptibility and risk assessment of debris flow geological hazards. The research results show that the area with high risk of landslides covers 14.22 km2, accounting for 3.30%; the area with medium risk of landslides covers 51.05 km2, accounting for 11.83%; the area with low risk of landslides covers 95.32 km2, accounting for 22.09%; the area with little probability of landslides covers 270.93 km2, accounting for 62.79% of the total study area. There are 17 high risk debris flows, 59 medium risk debris flows and 1 low risk debris flow. The assessment results can provide reference for the geo-hazard risk assessment and geo-hazard prevention and mitigation.

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Travelers Subjective Path Selection Model Considering Road Network Congestion Status

ZHANG Weihua, YAN Peng，HUANG Zhipeng

2019, 38(07): 90-95. DOI: 10.3969/j.issn.1674-0696.2019.07.15

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In order to accurately describe the travelers route choice behavior in uncertain environment, a subjective route choice model considering the congestion state of road network was proposed. Firstly, a probabilistic model of route travel time based on segment unit was constructed to reflect the impact of congestion state of road network on route travel time. Then, the cumulative foreground theory was used to model the travelers path choice behavior, and the solutions of subjective utility function, subjective probability function and path foreground value in the model were given. Finally, the influence of road network status, reference point and other factors on path selection behavior was analyzed by an example. The results show that the foreground value calculated by the model is not only related to the selection of psychological reference points, but also related to the congestion state of the road network, which can better reflect the actual travel path selection behavior.

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Discrimination of Urban Road Traffic Based on Set Pair Analysis

DAI Xuezhen1, YUAN Renteng1, PEI Wenjie2, PENG Zhipeng1

2019, 38(07): 96-101. DOI: 10.3969/j.issn.1674-0696.2019.07.16

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In order to improve the traditional way of judging the operation status of urban road traffic, a method of judging the operation state of urban road traffic based on set pair analysis and triangular fuzzy number α-cut set was proposed, according to the analysis of the evaluation method of traffic operation state at home and abroad. In the proposed method, the average travel speed, the ratio of road congestion mileage, the ratio of travel time and the ratio of road network delay time were taken as the discriminant indexes. Set pair H (An, Bk) was composed of set An (measured data) and set Bk (criteria for discriminating indicators), furthermore, the hierarchical relationship between similarities, differences and inverses of set pair theory was analyzed. Based on the coupling of set pair analysis and triangular fuzzy number α-cut set, the expression of connection degree was constructed, and the comprehensive evaluation model of weight and construction connection number was determined. Taking the measured data of the eastern section of the South Second Ring Road in Xian as an example, the proposed method was proved to be more accurate to reflect the road operation, through comparison and analysis with the traditional evaluation results.

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Evolution Modeling and Solution of the Integrated Passenger Transportation System

SONG Chengju1, ZHANG Yaping2

2019, 38(07): 102-106. DOI: 10.3969/j.issn.1674-0696.2019.07.17

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The integrated passenger transport system is evolving under the combined action of internal and external factors, but it is not clear about the mechanism of various modes of transport and the evolution trend of the whole system. By analyzing the self-organizing characteristics of the integrated passenger transport system, the passenger turnover was taken as the system variable, and the fluid motion equation was used to describe the system evolution process. Logistic model was used to describe the evolution process of the integrated passenger transport system. By introducing system random variables, the evolutionary equations were divided into two parts: Logistic equations part and the stochastic part. Matrices least squares method and K-order Fourier series fitting method were used to solve the evolutionary equations respectively. Combined with the actual data in Harbin, the validity of the proposed model was verified. The results show that the integrated passenger transport system presents obvious self-organizing characteristics. The evolution process of the integrated passenger transport system can be better described by the method of partial fitting, and the prediction accuracy meets the requirements.

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Topological Structure Model and Node Importance Analysis of Rail Transit Network

CHEN Weiwei1,ZHANG Fugui2,ZHAO Xiaobo2

2019, 38(07): 107-113. DOI: 10.3969/j.issn.1674-0696.2019.07.18

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The construction of rail transit network is becoming more and more complex, and the research on its key nodes and important transit stations is of great significance. The complex network theory was used to study the network topology and node importance of rail transit network. Firstly, the topological structure model of rail transit network based on second-order tensor was constructed. Then, the feature indexes such as the degree, degree distribution, network diameter, average path length and clustering coefficient of the model were analyzed, and the network node importance was evaluated by three central indexes. Finally, the proposed method was validated with Chongqing rail transit network as an example. The results show that in the long-term complex network of Chongqing rail transit — “Seventeen Lines and One Ring”, only 4% of the stations are directly connected with another station, and the connectivity of the network is quite good. The four stations of Wulidian, West Chongqing, Shapingba and Ranjiaba have the greatest impact on the connectivity of the network.

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Modal Optimization of BIW Based on Concept Feature Model

ZHANG Yu1, CAO Youqiang2

2019, 38(07): 114-118. DOI: 10.3969/j.issn.1674-0696.2019.07.19

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First of all, using the mechanical properties of the body joint unit, the modeling method of the joint conceptual model was studied, and the high-precision BIW concept feature model was established. Then, the sensitivity of main beams and joints was analyzed and calculated based on the BIW concept feature model. The sensitive area of bending and torsion modes of BIW was identified as an index, and the modal optimization guidance was proposed. Finally, the modal optimization measures were transplanted to the real car model of BIW. The calculation and verification results show that the bending and torsion modal frequencies of BIW are optimized. It is a convenient and effective method to optimize the BIW structure by using the conceptual feature model to form a complete set of modal optimization process of BIW, which greatly improves the efficiency of NVH performance development of BIW.

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Development and Research on Analysis Process of Whole Vehicle Noise Subjected to Road Surface Spectrum

SHEN Yang, HUANG Yuanyi, LIANG Jingqiang, CHANG Guangbao, LV Zhaoping

2019, 38(07): 119-125. DOI: 10.3969/j.issn.1674-0696.2019.07.20

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In order to analyze the interior noise in the vehicle caused by the road random excitation, a standard road noise analysis process based on HyperWorks-NVHD was formulated. On the basis of modeling theory of modal tire, the modal tire model was built and integrated with the simulation model of whole vehicle. Then, the actual road surface excitation was obtained by road testing. The road noise random response analysis method was developed, and OptiStruct solver was used to diagnose the peak value of the noise problem. The main cause of noise problem was found out, and then the body structure and transmission path were optimized. The problem of road noise risk of a certain type of vehicle was successfully solved. The validity and feasibility of the proposed process were verified by the test of sample production.Because the analysis process does not depend on the specific vehicle type, the portability of the method is realized to the greatest extent.

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CO2 Emission of Fuel and Pure Electric Vehicle in the Process of Circulation

HE Yituan, ZHANG Pengbo, SHAO Yiming, TAO Youdong

2019, 38(07): 126-130. DOI: 10.3969/j.issn.1674-0696.2019.07.21

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With the continuous progress of social production technology and the increasing number of vehicles, the problem of environment and energy has become increasingly prominent. Based on the consumption of oil resources in China in 2016 and the energy structure of the State Grid, the CO2 emission of traditional fuel vehicles and pure electric vehicles in the process of circulation was calculated. If half of the fuel consumption in 2016 was replaced by electricity, a additional power generation of 809.6 bill. kW·h woule be needed, which accounted for 13.18% of the total power generation in 2016. To cut CO2 emissions by half and mainly replace gasoline vehicles with electric vehicles, more than 190 million additional electric vehicles needed to be added and charging power of 570.06×106 kW would be increased, which put forward higher requirements for the current grid load. Compared with the electrification of traditional fuel vehicles, reasonable reduction of coal consumption in power grid structure has more positive significance for reducing CO2 emissions.

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