Home Archive
Archive
2024 Volume 14 Issue 1  Published: 2024-02-20
   Next
    Review and Rrospect
  • Geng ZHANG , Chao YANG , Weida WANG , Ying LI
    doi: 10.3969/j.issn.2095–1469.2024.01.01

    Simultaneous localization and mapping (SLAM) technology enables autonomous vehicles to estimate their own poses and establish the map of an unknown environment according to the data collected by onboard sensors. SLAM can provide localization information to the decisionmaking module for vehicle planning, and has become one of the research hotspots of autonomous driving technology in recent years. Based on the point cloud data collected by LiDAR, this paper focuses on the SLAM technology applied in autonomous driving. The related research at home and abroad has been reviewed including the frontend odometry, the backend optimization and loop closure detection. Due to the limitations of a single sensor, the opportunities and challenges of multisensor fusion SLAM technology for autonomous driving are discussed based on the research hotspots and difficulties in the field of multisensor fusion.

  • Low-Carbon Technologies Setion
  • Jiangkun SHI , Caiying SHEN , Xin CHEN
    doi: 10.3969/j.issn.2095-1469.2024.01.02

    Focusing on a hybrid electric vehicle equipped with a lithium battery and supercapacitor, the paper establishes a realtime wavelet transformfuzzy control energy management control strategy. The objective is to enable the supercapacitor to handle high frequency signals at a reasonable state of charge (SOC) and the lithium battery to manage low frequency signals, all under the premise of satisfying dynamic performance requirements. Secondly, the vehicle model was developed based on Matlab/Simulink and ADVISOR software, and simulation tests were carried out under NEDC cycle conditions. The simulation results show that, compared with the single lithium battery, the peak driving current of the lithium battery in the composite power supply is reduced by 20.68% and its lifespan is increased by 16.75% under the wavelet transformfuzzy control strategy. Finally, a scaleddown experimental platform of the composite power system was built and tested under NEDC conditions. The experimental results show that the proposed control strategy effectively manages the energy of the hybrid electric vehicle.

  • Low-Carbon Technologies Setion
  • Yongtao LIU , Yongjie LIU , Shiquan YUAN , Yulong LI , Yisong CHEN
    doi: 10.3969/j.issn.2095–1469.2024.01.03

    To quantitatively evaluate the environmental benefits of the recycling process for new energy vehicle power batteries, and to provide support for the improvement of the management system and relevant standards for endoflife power batteries, thereby assisting in the implementation of the national “twocarbon" goal, the paper selects ternary lithium batteries as the research subject. The paper identifies typical scenarios for power battery recycling and utilization, divides the lifecycle of ternary lithium batteries into four stages: raw materials acquisition, manufacturing and assembly, usage, and scrap recovery and establishes the corresponding GaBi model. Based on different recycling methods, such as wet recycling A, wet recycling B, and firewet combined recovery, a life cycle evaluation model for ternary lithium batteries was built and the carbon reduction efficiency of the recycling and reuse process was calculated. The research results show that the recycling of ternary lithium batteries significantly reduces carbon reductions. Specifically, the carbon dioxide emission reductions for each recycling method are as follows: 60.71 kg CO2/kWh for wet recycling A, 150.00 kg CO2/kWh for wet recycling B, and 153.57 kg CO2/kWh for firewet combined recycling. The carbon dioxide emission reduction efficiency of the three different recovery processes is ranked from best to worst as follows: firewet combined recovery, wet recovery B and wet recovery A. Proper recycling of power batteries can significantly reduce carbon emissions during the recycling process, thus producing greater environmental benefits.

  • System Dynamics Setion
  • Xiang FU , Maojia TANG , Luzhe SUN
    doi: 10.3969/j.issn.2095–1469.2024.01.04

    To achieve multiobjective optimization of power performance and stability for inwheelmotor driven offroad vehicles in complex environments with variable adhesion conditions and undulating road surfaces, the paper proposed an adaptive torque control strategy based on pavement impact factors. Five characteristic parameters, namely, the difference in rolling resistance, normalized proportion of air resistance, normalized proportion of ramp resistance, variance of road adhesion difference and the minimum road adhesion coefficient, were used as inputs to establish a fiveparameter identification model of pavement impact factors based on fuzzy theory. Considering the identified pavement impact factors, an adaptive torque control strategy was developed for the multiobjective optimization of vehicle power performance and stability, and a threelayer control architecture was constructed. At the top of the strategy, the pavement impact factors are introduced to determine the urgency of acceleration, and the model predictive control algorithm is used to obtain the desired total driving force. The middle layer serves as the target decisionmaking layer, which governs the antiskid torque based on the optimal slip rate, and determines the desired feedforward compensation torque according to the road resistance. The base layer servers as the torque distribution level, taking the total demand driving force and the tire utilization ratio as the control objectives. It introduces the pavement impact factors to optimize the weight coefficients of these two objectives. A hybrid optimization algorithm with multiple constraints is applied for adaptive torque control. Simulations were conducted using the Matlab/SimulinkCarSim cosimulation platform, with real vehicle trials for verification. The results show that on lowadhesion road surfaces, the wheel slip control can be achieved rapidly within 0.2 s. On the split road surfaces, the lateral displacement is nearly negligible, showing excellent lateral stability. On highly twisted road surfaces, the system prevents large slip rates of the freespinning wheel from exceeding 0.2.

  • System Dynamics Setion
  • Kai CHEN , Shaoyang SHI , Shanshan CHENG , Yechen QIN
    doi: 10.3969/j.issn.2095–1469.2024.01.05

    Road surface unevenness significantly affects both the driving safety of road vehicles and their dynamic responses. However, the existing datadriven methods for road surface classification struggle to efficiently handle timevarying parameters and vehicle speeds. Meanwhile, the existing modelbased road surface recognition algorithms require known and accurate vehicle models, facing the challenge of acquiring vehicle physical parameters in realworld applications. This paper proposes a novel pavement classification algorithm that begins by backcalculating the equivalent pavement profile, followed by data preprocessing. Subsequently, it computes time and frequency domain features for the equivalent pavement profile and response information, and key features are extracted using the ReliefF algorithm. A radial basis function neural network is used to construct a classifier for pavement grading and recognition. Finally, the robustness of the proposed algorithm is verified through simulation tests and realvehicle tests with different vehicle parameters and speeds.

  • System Dynamics Setion
  • Qingyang WANG , Yao XIAO , Yanfei WU , Zhiming ZHAO , Fayue MA
    doi: 10.3969/j.issn.2095–1469.2024.01.06

    Optimizing the aerodynamic performance of the vehicle chassis has an important impact on reducing the aerodynamic drag and lift of the vehicle. The optimized design in the chassis area is a crucial approach to improve the fuel economy and power of the vehicle. In this paper, a Computational Fluid Dynamics (CFD) simulation analysis of the external flow field is conducted for a sport utility vehicle (SUV). The paper compares the simulation accuracy of Realizable kɛ and SST kw turbulence models, ultimately selecting the Realizable kɛ turbulence model for the aerodynamic design of the chassis. Combining the SUV chassis characteristics and the flow field analysis, and aiming to minimize the overall cost, the paper designed five aerodynamic proposals for the chassis, including the front lower spoiler, the front wheel baffle, the subframe rear spoiler, the middle chassis guard and the tail muffler shape optimization. A fullscale wind tunnel test was carried out to verify the CFD simulation results. The results show that all five chassis proposals contribute to the improved aerodynamic performance. The tail muffler shape optimization has a notable impact on drag reduction, decreasing the vehicle's drag coefficient by 2.99%. When the five proposals are combined, the drag coefficient and lift coefficient are reduced by 5.16% and 21%, respectively. The study effectively achieves energysaving and drag reduction, and improves driving stability of the vehicle.

  • 2023 SAEAAC
  • Lijun TANG , Yafei CAO , Hu WANG , KUBO Tsunenori , Fengli ZHANG , Quili LUO , MASAKI Suzuki , Bo LU
    doi: 10.3969/j.issn.2095–1469.2024.01.07

    As the first pure electric sedan of BYD TOYOTA EV Technology Co., Ltd, the bZ3 has extremely high energy consumption requirements, which brings great challenges to its aerodynamic development. To achieve this target, CFD simulations and wind tunnel tests were conducted by the aerodynamics team. Optimizations were primarily focused on areas including styling, undercover design, cooling air inlet management, wheels and sealing. The final production car was tested in the wind tunnel, achieving a drag coefficient of 0.218, which is at a leading level among vehicles in its class. Different CFD methods were compared with test results, showing that the LBM has better accuracy, although its precision in simulating underbody airflow still needs to be improved.

  • 2023 SAEAAC
  • Zheming DONG , Jianwei QIANG , Rui SHI , Xiaobi WANG , Weimin WANG , Jing FU , Yu TANG , Xiaojia FU , Qifu HE
    doi: 10.3969/j.issn.2095–1469.2024.01.08

    With the continued expansion of the pure electric vehicle market, it is necessary to optimize the overall thermal management control strategy for BEVs in low temperatures. The optimization is crucial to better suit the application scenarios, particularly to meet the growing demands of customers in northern cold regions and to alleviate the decline in driving range of BEVs in lowtemperature environments. Based on research and realvehicle validation of the thermal management control strategies for waste heat source heat pumps and air source heat pumps in different lowtemperature scenarios for a BEV model, the paper has extended the effective operating lower temperature limit of the heat pumpbased thermal management system from 15 °C to 20 °C. Moreover, the attenuation rate of driving range has been significantly reduced to 31.2% under the CLTC driving condition at 7 °C.

  • 2023 SAEAAC
  • Zhicheng ZHU , Xiaohan ZHANG , Qiuli LUO , Fengli ZHANG , Wenjiang WANG
    doi: 10.3969/j.issn.2095–1469.2024.01.09

    The hollow roof spoiler has become a new trend in automotive styling design, significantly impacting the vehicle's aerodynamic performance. To study the influence of the spoiler parameters on aerodynamic drag coefficient, CFD simulations were conducted to analyze cases with different spoiler angles, passage sizes, and Dpillar spoilers based on a BYD hatchback model with a hollow roof spoiler. The simulation results agree well with wind tunnel experiment results. It is found that the volume of the upper tail flow increases with a decrease in the spoiler angle, a reduction in the passage size or the addition of a Dpillar spoiler. A lower drag coefficient is obtained when the upper tail flow more effectively matches with the lower tail flow. The findings of this paper are valuable for guiding future designs of hollow roof spoilers.

  • Other Technologies
  • Weixing WANG , Chunbo XIA , Quanzhou ZHANG , Yafei DU , Lei XU
    doi: 10.3969/j.issn.2095-1469.2024.01.10

    Due to factors that the wiper swing frequency does not match the structure of the waterguiding channel and the air conditioning (AC) external circulation inlet, some vehicle models under rainy conditions experience water droplets or even water flow entering the AC system through the inlet, leading to the unpleasant odors from the air conditioning, and even water leakage into the passenger compartment, causing serious perceived quality issues. By employing the SPH method considering wiper movement, body posture, and the effects of airflow conditions, the paper uses PreonLab software to simulate a vehicle in rainy scenarios to address the water management issues. By adding a baffle at the position of the AC external circulation inlet, the entry of the rainwater into the AC system is significantly reduced, and this solution is verified through the real vehicle tests under rainy conditions. The proposed method can find and rectify the unreasonable flow path designs for vehicles in the rainy scenarios during the development stage without relying on real vehicle tests. The method can also be applied to other performance quality control of vehicle water management, such as wading and rain pollution.

  • Other Technologies
  • Yu FU , Haitao MIN , Weiyi SUN , Fang YANG
    doi: 10.3969/j.issn.2095–1469.2024.01.11

    Under transient conditions, the opening of the car's active grille system(AGS) and the rotational speed of the fan are adjusted in realtime, leading to continuous changes in the air intake volume of the heat exchanger. Consequently, the fan of the thermal management test bench cannot provide accurate and immediate transient air supply for the heat exchanger. In this paper, computational fluid dynamics (CFD) simulation technology is used to analyze the relationship between the inlet air volume of the heat exchanger and factors such as vehicle speed, AGS opening and fan speed. Subsequently, a mathematical model is constructed with a prediction error of less than 6.6%. The model is then integrated into the CANOE device, connected to the VN1640 device and the fan system. The system can collect realtime CAN signals for vehicle speed, AGS opening, and fan speed, calculate the inlet air volume of the heat exchanger, and control the corresponding air volume output from the fan. It achieves the goal of providing the heat exchanger with accurate and realtime air supply through the bench fans.

  • Other Technologies
  • Hong YANG , Li CHEN , Chenqi ZOU , Mengyan ZANG
    doi: 10.3969/j.issn.2095–1469.2024.01.12

    Studying the impactinduced failure phenomenon of automotive coatings is of great significance for predicting damage and guiding the structural design and optimization of the coatings. A finite element model for the singleparticle impact failure of automotive coating samples is established, and this model is solved by using an inhouse explicit finite element solver, FTWGPU. The predicted failure patterns of inply failure and interface delamination of the automotive coatings are in good agreement with the experimental outcomes, which verifies the effectiveness of this numerical method and reveals the failure mechanisms of inply failure and interface delamination in coatings under impact load.

  • Other Technologies
  • Xiaoling WEI , Yong CAO , Guoqiang ZHAN , Jiuru XIAO
    doi: 10.3969/j.issn.2095–1469.2024.01.13

    The forward development of vehicle integration indicates the R&D capabilities of the automobile industry. Therefore the paper studied the evaluation and comparison of the forward development of vehicle integration among different automobile companies. According to the work content of forward development, a Vshaped development process was adopted and revised. An model involving 9 firstlevel indicators and 33 secondlevel indicators was built to evaluate the forward development of vehicle integration of seven Chinesebranded vehicle companies. It is found that the maximum value of the weight coefficient of product planning leads to the largest value of the forward development capability. The Company J with the best comprehensive performance has clear advantages in product planning, project management, vehicle function definition and vehicle performance integration without any unfavorable indicators. The evaluation scores of other companies are affected by their unfavorable indicators.

  • Other Technologies
  • Zhao XIE , Yalian YANG , Changdong LIU
    doi: 10.3969/j.issn.2095–1469.2024.01.14

    According to the definition rule of A2L file in automobile calibration system, the regular expression is designed to match the internal key information of A2L file, and the information of A2L file is represented by class structure and multitree model. In addition, the corresponding general analysis flow is proposed for different data modules in the file. Aiming at the problems of measurement value visualization and calibration value download, the conversion formula of raw quantity to physical quantity is designed according to various predefined types and conversion methods, which can provide conversion tools for upper computer software. The A2L data analysis management software is developed by using C# and window applications to realize the visual management and modification of the analysis results. The software design pattern of "high cohesion and low coupling" and dynamic link library are used to further develop the measurement calibration software. Finally, the effectiveness of the proposed A2L file parsing method is verified by experiments.

  • Other Technologies
  • Rongrong ZHANG , ZHANG Charles , Weifang HONG , Yongchao LI
    doi: 10.3969/j.issn.2095–1469.2024.01.15

    To overcome the challenges of NTF simulation accuracy in vehicle NVH simulations, the paper designed and constructed a “rigidwall occupant cabin", which reduced the coupling effect between the "acoustic cavity mode” and the “container" to a negligible extent. Based on the rigidwall passenger cabin, the influence of subacoustic cavities on the overall acoustic cavity mode was analyzed, and the modeling method for porous materials was discussed. The porous material models such as seats and carpets were established, and the effect of front wall sound insulation material on the coupling of sheet metal vibration and acoustic cavity mode was analyzed quantitatively. The simulation and test results show that the cavity mode, airborne sound transfer function, structural vibration transfer function and sound transfer function all achieve good simulation accuracy. The findings of this paper provide a reference for the control of low frequency road noise and engine noise.