Table of Content

25 June 2022, Volume 44 Issue 6 Previous Issue    Next Issue

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Intelligent Vehicle Autonomous Emergency Braking System Considering Safety of the Intended Functionality Dongkui Tan,Gangjun Hu,Bo Zhu,Lai Jin,Jie Zhang 2022, 44 (6):  799-808.  doi: 10.19562/j.chinasae.qcgc.2022.06.001 Abstract ( 445 )   HTML ( 47 )   PDF (2911KB) ( 650 )   Save The proposed safety of the intened functionality （SOTIF） has challenged the safety of traditional automatic emergency braking （AEB） system. To deal with it， this paper uses systems-theoretic process analysis （STPA） to obtain the SOTIF requirements of the AEB. On the basis of the traditional AEB， a safety speed planning strategy for the perceptual blind scenes is added. Then， based on the kinematics model of the encounter between the vehicle and the pedestrian in the perceptual blind scenes， the formula of blind scenes safe speed is constructed. Then a speed sliding mode controller with a nonlinear disturbance observer is designed to track and control the speed. Finally， the simulation test is carried out on the joint platform of CarSim and Simulink to compare the safety of the proposed system with the automatic emergency braking system without the intended functional safety requirements， which is further verified via the hardware-in-the-loop experiment. The results show that the AEB considering the SOTIF can effectively reduce the risk of pedestrian collision and ensure the efficiency of vehicles passing through blind spots safely. Figures and Tables | References | Related Articles | Metrics

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Pedestrian-Vehicle Micro-Interaction Model Based on Attention Field of Pedestrian Vision Wenli Li,Kaiwen Xiao,Xiaohui Shi,Fenghua Liang,Ping Li 2022, 44 (6):  808-820.  doi: 10.19562/j.chinasae.qcgc.2022.06.002 Abstract ( 199 )   HTML ( 12 )   PDF (5517KB) ( 225 )   Save From the perspective of pedestrian visual cognition， a pedestrian-vehicle micro-interaction model based on the atten-tion field of pedestrian vision is proposed. The attention field of pedestrian vision is constructed to drive the pedes-trian field of vision， and the artificial potential field is used to drive the pedestrian movement，. The target capture algorithm is used to control the target capture in the pedestrian visual field. In order to verify the effectiveness of the model， drones are used to collect the pedestrian-vehicle interaction data from the bird's-eye perspective and analyze them. Pedestrian crossing styles are divided into three types： conservative， cautious and adventurous. Simulation scenarios and interactive models are built on the Pygame platform， then， different types of interactive data are used as the model input， the similarity between the pedestrian spatiotemporal trajectory output by the model and the collected real spatiotemporal trajectory is experimentally compared. The results show that the pedestrian-vehicle mi-cro-interaction model based on pedestrian visual attention field is 25.48% more accurate than the conventional artifi-cial potential field model， and it can effectively reproduce the pedestrian-vehicle interaction process in the actual traf-fic scene. Figures and Tables | References | Related Articles | Metrics

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An Analysis on Longitudinal Driving Characteristics in Urban Intersection Based on Natural Driving Data Tian Yuan,Xuan Zhao,Rui Liu,Qiang Yu,Xichan Zhu,Shu Wang 2022, 44 (6):  821-830.  doi: 10.19562/j.chinasae.qcgc.2022.06.003 Abstract ( 183 )   HTML ( 9 )   PDF (3732KB) ( 214 )   Save In order to meet the higher requirements of driver assistance systems for human-like driving ability in urban intersection， the longitudinal driving characteristics of drivers in real traffic in that area are investigated in this paper. 778 sample data of drivers approaching urban intersections are extracted from natural driving data， and YOLOv4 is applied to identifying various types of road users in traffic scene. ANOVA is used to investigate the differences in reaction characteristics across motion types and traffic densities， and hierarchical regression models are established to analyze the relationships between braking characteristics and motion state， motion type and road users. The results show that high-density traffic significantly reduces approaching speed. Compared with right-turning drivers， stopping drivers have longer reaction distance and may approach intersection with higher acceleration and braking intensity in a shorter time with braking started 4.46s earlier when approach speed is higher or reaction distance is shorter. Different road users have different effects on braking characteristics： stopping drivers primarily pay attentions to the vehicles traveling in the same direction， and right-turning drivers are mainly concerned with pedestrians and cyclists. Figures and Tables | References | Related Articles | Metrics

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Trajectory Planning of Intelligent Vehicles in Lane Change for Collision Avoidance Based on Segmented Optimization Bin Tang,Zhanxiang Xu,Haobin Jiang,Yingfeng Cai,Zitian Hu,Zhengyi Yang 2022, 44 (6):  831-841.  doi: 10.19562/j.chinasae.qcgc.2022.06.004 Abstract ( 252 )   HTML ( 19 )   PDF (3847KB) ( 335 )   Save In order to enhance the safety and comfort of intelligent vehicle during lane change for collision avoidance under complex road scenes， a trajectory planning method of intelligent vehicle lane change for collision avoidance is proposed based on segmented optimization. Firstly， according to the state of ego vehicle and multiple sampling points， candidate y-x curve clusters and x-t curve clusters are generated based on quintic polynomials with consideration of various possibilities of lane change. Then， by designing an obstacle risk evaluation function based on exponential function， and combined with the smoothness， altruism and driving efficiency of the trajectory， a comprehensive evaluation system is constructed to select the optimal reference trajectory， providing the direction and speed references for intelligent vehicle lane change for obstacle avoidance and preventing the solution from falling into local optimum in trajectory optimization. For suiting to the time-varying features of the obstacle movement state， the piecewise quintic polynomial y-x curve and x-t curve are constructed with the reference trajectory as a guide， and the optimization objective function is also established with consideration of the risk of collision with obstacle vehicles， converting the trajectory optimization problem into a constrained nonlinear programming one to find out the optimal trajectory by exterior point method. Finally， the simulation verification is performed on MATLAB platform with a result showing that the trajectory planning method proposed enhance the environmental adaptability and obstacle avoidance adjustment ability of vehicles， while meeting the requirements of lane-change smoothness and ride comfort. Figures and Tables | References | Related Articles | Metrics

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Research on the Test and Evaluation Technique of Real Roads for Automated Driving Vehicles Based on OEDR and ODC Hang Sun,Zhijun Li,Linlin Zhang,Zhenyu Chen,Shilong Li 2022, 44 (6):  842-850.  doi: 10.19562/j.chinasae.qcgc.2022.06.005 Abstract ( 240 )   HTML ( 7 )   PDF (1226KB) ( 669 )   Save In this paper， a classification method of test roads is proposed based on the object and event detection and response （OEDR） task of the automated driving system， the road element fundamental model is constructed based on the operation design domain， and the effective Jaccard similarity method is modified for the conformity assessment of test road. In addition， a test and assessing method based on the boundary of operation design condition is also put forward according to the selection of test road， and combined with occupant subjective evaluation， a test and evaluation system for automated driving vehicles on real road is built. The results of test on typical roads in China show that the test and evaluation system proposed has good feasibility and universality， being able to be widely applied as a standardized method. Figures and Tables | References | Related Articles | Metrics

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Research on Eco-driving of Fuel Cell Vehicles via Convex Optimization Xiaodong Wei,Bo Liu,Jianghao Leng,Xingyu Zhou,Chao Sun,Fengchun Sun 2022, 44 (6):  851-858.  doi: 10.19562/j.chinasae.qcgc.2022.06.006 Abstract ( 301 )   HTML ( 19 )   PDF (3157KB) ( 333 )   Save In order to realize eco-driving of fuel cell vehicles in the multi-signal scenario， a fast speed planning and energy management method based on hierarchical convex optimization is proposed in this paper. Combined with the static hydrogen consumption map of the vehicle， dynamic programming is used to obtain the optimal period of green light for the vehicle while passing through the traffic light， and to determine the search area for the optimal driving route. A quadratic programming problem is established to obtain the acceleration with the minimum accumulated power demand as the optimization objective， and the Matlab/OSQP solver is used to obtain the optimal driving path of the vehicle. According to the optimal driving route， an energy management strategy based on the alternating direction method of multipliers is established to realize the reasonable distribution of the output power of each power source. The simulation results for the scenario with 9 traffic lights show that the average efficiency of the motor operating point of the proposed method is 10% higher， and the hydrogen consumption is 45% lower than that of the intelligent driver model. In addition， the method has fast calculation speed and the potential for real-time optimization. Figures and Tables | References | Related Articles | Metrics

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Improved Design of Battery Module Cooling System Under the Influence of Busbar Heat Generation Yuming Peng,Mingxiao Yuan,Zhuoxin Jing,Yonglin Zhang,Gang Huang 2022, 44 (6):  859-867.  doi: 10.19562/j.chinasae.qcgc.2022.06.007 Abstract ( 171 )   HTML ( 6 )   PDF (3248KB) ( 205 )   Save In this paper， a reliable cell heat generation model is established by using Bernardi heat generation rate equation through simulation and experimental verification， and the simulation and experimental error is less than 2%. Based on this， the heat generation model of the module under the influence of the bus-bar heat generation is established. For improved design of the original cooling system for insufficient cooling effect on the top area of the module and the bus bar， for the cooling plate arrangement， it is proposed to install the cooling plate on the side of the module， and then to select the appropriate cooling plate thickness， cooling fluid volume concentration and the coolant inlet velocity through simulation analysis. In the final design， the average temperature rise of the bus-bar of the cooling system module， cell and top surface of the module is reduced by 15.56%， 11.48% and 20.34% respectively， and the temperature distribution on the cell of the module is more uniform. Figures and Tables | References | Related Articles | Metrics

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Capacity Estimation of Lithium-ion Battery Based on Deep Learning Under Dynamic Conditions Guihong Bi,Xu Xie,Zilong Cai,Zhao Luo,Chenpeng Chen,Xin Zhao 2022, 44 (6):  868-878.  doi: 10.19562/j.chinasae.qcgc.2022.06.008 Abstract ( 215 )   HTML ( 10 )   PDF (2323KB) ( 236 )   Save In the aging course of lithium-ion battery， nonlinear complicated changes occur inside the battery， therefore directly using the operation data of lithium-ion battery such as current， voltage and temperature in certain time sections to conduct real-time estimation on the battery state of health under dynamic condition is a challenging issue. In this paper， the random charging and discharging data of lithium-ion battery are selected， the time and frequency features of some segments of dynamic data are extracted to compose time and frequency feature matrices as input， a cascaded convolutional neural network and a gated recurrent unit capacity estimation model are constructed to extract the intrinsic features of input data， and the related features of each time sequence are further explored to fulfill the estimation of battery capacity under dynamic condition. The results of experimental verification utilizing NASA's lithium-ion battery random use data set show that the method adopted can accurately estimate the capacity of lithium-ion battery under the condition of only the nominal capacity of battery is known. Finally， the effects of the setting of model’s hyper-parameters， the time-sequence length of raw data， network input and model structure on the accuracy of battery capacity estimation are analyzed. Figures and Tables | References | Related Articles | Metrics

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Simulation Analysis on Blunt Aortic Injury of Vehicle Occupants Fang Tong,Xiong Li,Fengchong Lan,Jiqing Chen 2022, 44 (6):  878-885.  doi: 10.19562/j.chinasae.qcgc.2022.06.009 Abstract ( 142 )   HTML ( 4 )   PDF (3372KB) ( 182 )   Save The refined heart aorta model established earlier are filled with blood based on the fluid-cavity function of software Abaqus， a blood-heart aorta liquid-solid coupling model is constructed， and the fluid exchange with different flow rates are set on aortic valve according to the pressure difference between left ventricle and aorta. Simulations on the frontal crash of driver against steering wheel are carried out under different working conditions to analyze the effects of the cardiac blood output and the inclined angle of steering wheel on the blunt aortic injuries of driver. The results show that ：（1） The blood flow from left ventricle to aorta reduces the peak blood pressure of left ventricle and alleviated the blood pressure fluctuations in the aorta， but the effect on the maximum stress of aorta is not significant； （2） When the tilted angle of steering wheel is 30°， the maximum stress in the aorta reaches 2417 kPa， which is caused by the pressing of anterior chest wall on ascending aorta； （3） When the tilted angle of steering wheel is 60°， the maximum stress in the aorta lowers to 1375 kPa， which is caused by the relative tensile displacement between aortic root and descending aorta. Figures and Tables | References | Related Articles | Metrics

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Study on Crashworthiness of Self-Similar Hierarchical Honeycomb Structure Under Multiple Collision Conditions Fangwu Ma,Hao Sun,Hongyu Liang,Wenting Ma,Qiang Wang,Yongfeng Pu 2022, 44 (6):  886-892.  doi: 10.19562/j.chinasae.qcgc.2022.06.010 Abstract ( 148 )   HTML ( 7 )   PDF (6656KB) ( 153 )   Save Enlightened by horsetail plant， a bionic self-similar hierarchical honeycomb structure is proposed in this paper. Based on the finite element model verified by test， the crashworthiness performance of the novel and traditional honeycomb structures under multi-angle oblique collision conditions are comparatively analyzed， including deformation modes， stress-strain curves and energy absorption characteristics. The results show that the self-similar hierarchical honeycomb structure has stable deformation mode under both ideal frontal and oblique impact conditions， and stable and excellent energy absorption performance when the impact angle changes. Figures and Tables | References | Related Articles | Metrics

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Research on Assessment Method of Lower Extremity Injury of Child Pedestrian Under Typical Conditions Specified in Euro NCAP TB024 Haiyan Li,Kun Li,Yongqiang Huang,Lijuan He,Shihai Cui,Lü Wenle,Shijie Ruan 2022, 44 (6):  893-899.  doi: 10.19562/j.chinasae.qcgc.2022.06.011 Abstract ( 136 )   HTML ( 2 )   PDF (4258KB) ( 153 )   Save In this paper， the finite element models for the front-end structure of four typical vehicles， i.e. family car （FCR）， multi-purpose vehicle （MPV）， roadster （RDS） and sport utility vehicle （SUV） specified in Pedestrian Human Model Certification （TB024） of the Euro NCAP protocol and a finite element model for six-year-old child pedestrian with detailed anatomical and structural features are used to simulate the child pedestrian-car crash accident with the effects of the structural parameters of vehicle front-end on the lower extremity injuries of children pedestrians analyzed under typical conditions. The results show that the RDS causes the fractures in the greater trochanter of impact-side femur of children pedestrians due to the smaller ground clearance of the front edge of engine hood， and the high ground clearance of the spoiler in MPV and SUV leads to the more severe injuries in tibia， fibula and knee ligament of lower limbs. Finally a parameter of sectional bending moment of long bones is proposed for assessing the lower extremity injury of six-year-old child pedestrian based on the simulation results， providing references for the development and digital assessment of child's leg impactor. Figures and Tables | References | Related Articles | Metrics

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Cooperative Control of Vehicle Lateral and Longitudinal Stability Based on Dynamic Stability Region Sensen Cong,Feng Gao,Shucai Xu 2022, 44 (6):  900-908.  doi: 10.19562/j.chinasae.qcgc.2022.06.012 Abstract ( 292 )   HTML ( 23 )   PDF (1910KB) ( 304 )   Save The transverse and longitudinal stability control of chassis is one of the important aspects of vehicle safety. According to the transverse and longitudinal parameter characteristics of the vehicle in the stability region， based on the stability analysis of dynamic region and the corresponding stability controller， a transverse and longitudinal cooperative stability control method is designed. Firstly， the stability analysis method is established based on the traditional vehicle foundation stability region； secondly， a dynamic stability region suitable for different vehicle working conditions is constructed， so that the stability region does not need to be re-estimated for different steering angles and vehicle speeds； on this basis， a stable amplitude limiting control algorithm is designed； finally， taking the sliding mode surface as the boundary of the stability region， a dynamic sliding mode controller is designed to keep the vehicle state stable all the time. Through the joint simulation of Matlab/Simulink and CarSim， the effectiveness of the transverse and longitudinal stability control method is verified in the high-speed steering scene and double line shifting scene. Figures and Tables | References | Related Articles | Metrics

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Cross-Country Road Classification Method Based on Vehicle Dynamic Response Characteristics Jian Zhao,Yaxin Li,Jing Tong,Bing Zhu,Weixiang Wu,Bohua Sun,Jiayi Han 2022, 44 (6):  909-918.  doi: 10.19562/j.chinasae.qcgc.2022.06.013 Abstract ( 198 )   HTML ( 12 )   PDF (2433KB) ( 264 )   Save Terrain classification based on vehicle dynamic response is one of the key technologies of off-road intelligent vehicles. In this paper， a method of off-road terrain classification， combining the terrain roughness features and mechanical characteristics， is proposed， with the sand， dirt， cement and snow roads classified. In this method， the equivalent terrain profile and the vertical acceleration of vehicle body are selected as the characteristics of terrain roughness， with the driving resistance and wheel speed fluctuation as the mechanical characteristics， the cross-country road classifier is designed based on LSTM model， and the training and testing are conducted on the cross-country driving dataset of vehicle. The results show that the correct rate of terrain classification reaches 95.5%. Finally， the post-processing of classification is fulfilled by using HMM model to solve the issue of the abrupt change of continuous data， enabling the correct rate of the algorithm in terrain classification with off-road continuous data rises from 88.44% to 90.13%. Figures and Tables | References | Related Articles | Metrics

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Active Control of Engine Noise in Vehicle Based on FPSC-FxLMS Algorithm Yansong He,Hao Jiang,Zhifei Zhang,Tao Zhou 2022, 44 (6):  919-928.  doi: 10.19562/j.chinasae.qcgc.2022.06.014 Abstract ( 158 )   HTML ( 3 )   PDF (6154KB) ( 203 )   Save The key to active noise control is to accurately estimate the amplitude and phase of the controlled noise. PSC-FxLMS algorithm adds the phase information of noise signal onto the Command signal and thus can emit a smaller anti-noise than Command-FxLMS algorithm does， but it is restricted by the estimation accuracy of secondary path and the phase extraction speed of Fourier transform. Taking the engine noise in a SUV as the object of research， the filter PSC-FxLMS （FPSC-FxLMS） algorithm is proposed in this paper， and with the noise information collected at the 4 seat headrest positions in the SUV as the primary noise， a simulation is conducted to compare the effects of the FPSC-FxLMS algorithm proposed and Command-FxLMS algorithm in the concurrent control of 2nd and 3rd order engine noise. Then a real vehicle test is also carried out on another SUV based on DSP hardware platform to compare again the effects of two algorithms. The results show that in controlling the engine noise at the left and right ear positions of the driver and the occupant behind driver， the anti-noise amplitude of 4th order noise with the algorithm proposed is lower than that with Command-FxLMS algorithm by over 25% in 800 r/min idle condition， while the anti-noise amplitude of 2nd order noise with the algorithm proposed is lower than that with Command-FxLMS algorithm by over 50% in a 1 900 r/min no-load condition. So it is demonstrated that the FPSC-FxLMS algorithm proposed can rapidly and accurately extract the phase information of engine noise at different rotational speeds， enabling the speaker emit a smaller anti-noise than the Command-FxLMS algorithm does. Figures and Tables | References | Related Articles | Metrics

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Nonlinear Dynamic Stiffness Model of Rolling-Lobe Air Spring Based on Payne Effect Mingyu Wu,Zhigang Chen,Hao Tong,Jing Wang,Hang Yin,Wenbo Zheng,Yao Li,Zhen Yu,Yintao Wei 2022, 44 (6):  929-935.  doi: 10.19562/j.chinasae.qcgc.2022.06.015 Abstract ( 164 )   HTML ( 6 )   PDF (1735KB) ( 181 )   Save In this paper， a nonlinear dynamic stiffness model of rolling-lobe air spring with consideration of the Payne effect of the rubber and the hysteresis characteristics of the thermodynamic equivalent stiffness and damping is proposed to overcome the difficulty in modeling the nonlinear dynamic stiffness of air spring and provide a theoretical basis for the structural design and material selection of rolling-lobe. Firstly， parameter identification is conducted for the real and imaginary parts of dynamic stiffness by indicator diagram test， showing that the Payne effect of rubber causes the increase of dynamic stiffness under small amplitude with the correctness of the model under the excitations with different amplitudes and frequencies verified. Then， the physical explanation of the changing trend of the contribution of each decoupled variables is given from the two dimensions of amplitude and frequency. The results indicate that due to the Payne effect of the rubber， the real part of dynamic stiffness reduces and its imaginary part increases first and then gradually reduces with the increase of amplitude. And due to the stiffness of air and the equivalent damping generated by heat exchange， the real part of dynamic stiffness gradually increases and its imaginary part increases first and then reduces with the increase of frequency. Finally， a new evaluation indicator reflecting the contribution ratio of the dynamic stiffness of the rubber lobe is given， which can directly characterize the low-amplitude dynamic performance and the rationality of structural design and material selection of air spring. The test results indicate that this indicator obviously reduces with the increase of amplitude， so the dynamic stiffness at low amplitude generated by rubber lobe should not be ignored. Figures and Tables | References | Related Articles | Metrics

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Research on Vehicle Thermal Balance and the Effects of Parameters on Thermal System Performances Based on 3D/1D Strongly Coupled Model Yingchao Zhang,Jiesong Jian,Jintao Zhang,Guohua Wang,Yuanbin Yu 2022, 44 (6):  936-944.  doi: 10.19562/j.chinasae.qcgc.2022.06.016 Abstract ( 188 )   HTML ( 12 )   PDF (3652KB) ( 221 )   Save The parameter changes of the vehicle thermal management system affect its performances， so it is necessary to use new methods to concurrently study multiple performance indicators in different dimensions. In this paper， an 1D/3D strongly coupled model of the vehicle thermal management is constructed by using the AMESim and the STAR-CCM+. This model can study various performances including the 3D and 1D temperature and flow fields under different thermal balance conditions at the same time. The corresponding 1D analysis results show that the heat dissipation capability of the cooling system is the worst under climbing condition， and the refrigeration capacity of the air conditioning system is the worst under idle condition. In order to study the influence of the parameter changes of thermal management system on its performance， the effects of the fan and water pump speeds on the cooling capacity of cooling system under climbing condition， and the influence of the fan and compressor speeds on the refrigeration capacity of air conditioning system under idle condition are analyzed. Figures and Tables | References | Related Articles | Metrics

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Selection of Body-in-White Material Based on Life Cycle Assessment Lijun Zhang,Ze Gao,Haiyan Yu 2022, 44 (6):  945-952.  doi: 10.19562/j.chinasae.qcgc.2022.06.017 Abstract ( 196 )   HTML ( 9 )   PDF (5774KB) ( 259 )   Save In this paper， life cycle assessment method is adopted to analyze the equivalent carbon emission and energy consumption of a fuel vehicle with four different materials i.e. common steel， advanced high strength steel （AHSS）， aluminum alloy and carbon fiber reinforced polymer （CFRP） as the material of its body-in-white in different stages of production， use （driving operation） and recovery after discard， with the influences of driving mileage on the emission reduction effects of different materials discussed. The results show that under current technical conditions， using AHSS and aluminum alloy to replace common steel as the material of body-in-white can reduce carbon emission and energy consumption， while using CFRP to replace common steel may increase the carbon emission and energy consumption. The life cycle carbon emission of aluminum alloy mainly depends on that in its production stage， while the selection of material is related to the carbon emission and energy consumption level in the region： in the region with general carbon emission and energy consumption level， aluminum alloy is superior than AHSS， while in the region with high carbon emission and energy consumption level， AHSS is superior than aluminum alloy. With the increase of driving mileage， the emission reduction effects of aluminum alloy become more remarkable. In a condition that the driving mileage of the fuel vehicle reaches 150 thousand km， it will get the comprehensively optimum carbon emission and energy consumption level when the materials of its body-in-white have a proportion of 77.9% AHSS versus 22.1% aluminum alloy. Figures and Tables | References | Related Articles | Metrics