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Segmented current diagnostics for mode switching and fuel cell mode startup behavior in unitized regenerative proton exchange membrane fuel cells

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Energy Conversion and Management 2025年 336卷

作者： Chen, Wenshang Meng, Kai Luo, Zongkai Deng, Qihao Zhang, Ning Chen, Ke Chen, Ben Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China School of Mechanical and Electrical Engineering Wuhan Business University Wuhan430056 China

In dual-mode operation, the unitized regenerative proton exchange membrane fuel cell (UR-PEMFC) experiences complex water–gas dynamics, particularly during mode switching in the constant-electrode (CE) configuration, where hydrogen and oxygen channels can cross-contaminate. Optimizing the mode-switching strategy enhances both round-trip efficiency and the speed and stability of transitions between electrolysis cell (EC) and fuel cell (FC) modes. This study introduces printed circuit board (PCB) segmented current technology for the first time in UR-PEMFC testing, enabling in-situ monitoring of current density distribution in both FC and EC modes. By analyzing the current density distribution and uniformity index under typical mass transfer faults, an in-situ diagnostic system for mass transfer was developed, facilitating optimized mode switching. Results indicated that, despite nitrogen and hydrogen–oxygen purging, FC mode startup was susceptible to flooding and dehydration risks. At 0.3 A/cm2, flooding occured when the uniformity index exceeded 125 mA/cm2, while dehydration risk was observed when the index ranged from 30 to 125 mA/cm2. Stable startup was achieved when the uniformity index was below 30 mA/cm2. Case comparisons suggested that nitrogen purging at 70 % humidity (1200 ml/min for 2 min) and hydrogen–oxygen flow at 200 ml/min, with a 300-second delay at 0.2 A/cm2, ensured rapid and stable mode switching from EC to FC at 0.3 A/cm2. This work provides valuable insights into optimizing mode switching in UR-PEMFC systems and offers a reliable approach for enhancing their operational efficiency and stability. © 2025 Elsevier Ltd

关键词： Diffusion in solids

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Microstructure inheriting evolution and strength-plasticity collaborative improvement mechanism of multidirectional rotary forged Al7075 sheets during T6 heat treatment

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Journal of Materials Science & technology 2024年第36期203卷 14-38页

作者： Xuan Hu Xinghui Han Lin Hua Jishi Zhang Jing Xu Fang Chai Wuhao Zhuang Fangyan Zheng Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

Al7075 sheets are widely used in aerospace industry and their higher strength-plasticity collaborative improvement requirement is *** this study,the microstructure inheriting the evolution and me-chanical properties of Al7075 sheets during multidirectional rotary forging(MRF)and T6 heat treatment are *** results show that the average grain size exhibits near-parabolic evolution with increas-ing MRF deformation ***20%+T6(20%MRF deformation amount+T6)condition possesses the largest grain size of 72.6μm,and its abnormal grain growth mechanism is that the medium deformation energy and high deformation heterogeneity in MRF20%deformed grains could cause asynchronous re-crystallization behavior during T6 heat treatment,and the grains with comparatively higher deformation energy get recrystallized firstly and devour adjacent grains along preferred011or223misorientation ***70%+T6 condition possesses the finest grain size of 14.2μm,and its fine grain inheriting mech-anism is that the uniformly high deformation energy in MRF70%deformed grains causes uniformly rapid recrystallization,and rapidly recrystallized grains effectively suppress grain boundary motion from adja-cent *** increasing MRF deformation amount,tensile strength and elongation values both exhibit near-antiparabolic ***70%+T6 condition possesses the largest tensile strength(563 MPa)and elongation(17.73%),which increases by 8.27%and 80.55%compared to as-annealed+T6(MRF0%+T6)condition(tensile strength is 520 MPa and elongation is 9.82%),*** strength-plasticity col-laborative improvement is mainly because the combination of effectively inherited fine grains,refined inclusion particles,and uniformly distributed fineη’particles after T6 heat treatment could promote smooth dislocation movement and coordinated slip behavior in most matrix grains,which contributes to the delay of stress localization and strength-plasticity collaborative improvement.

关键词： Al7075 sheets Multidirectional rotary forging T6 heat treatment Microstructure inheriting evolution Strength-plasticity collaborative improvement

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Picosecond laser ultrasonic imaging detection of near-surface micro defects using PCS and SAFT algorithm

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Ultrasonics 2025年

作者： Kangwen Huang Xiaokai Wang Shutong Dai Yu Peng Yan Zeng Lin Hua Shanyue Guan Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan 430070 China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Wuhan 430070 China School of Automotive Engineering Wuhan University of Technology Wuhan 430070 China College of Power Engineering Naval University of Engineering Wuhan 430030 China

The effective detection and imaging of near-surface micro defects has been the key problem in the ultrasonic inspection field for a long time. Laser ultrasound has high resolution and sensitivity which is the effective technology to detect micro defects. In this paper, the time and frequency domain characteristics of the picosecond laser ultrasound and the interaction mechanism between micro defects and ultrasonic waves are studied by simulation and experiment. A picosecond pulsed laser is used to excite ultrasonic waves in samples with near-surface micro defects of different depths, and the propagating ultrasonic waves are detected by an optical interferometer. Through the analysis of the experimental results, the near-surface micro defects with diameters of 0.13 mm and depths of 0.3 mm, 0.5 mm, 1 mm and 2 mm can be detected. In addition, a defect imaging algorithm combining principal component subtraction (PCS) and synthetic aperture focusing technique (SAFT) is proposed, which can effectively suppress the detection blind areas and artifacts caused by Rayleigh (R)-wave interference. Compared with the conventional total focusing method (TFM) of water-immersion ultrasound, the average SNR is increased by 25.57 dB. This research is poised to contribute to the resolution of quality assessment challenges in product manufacturing and service processes.

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On the deformation behavior of heterogeneous microstructure and its effect on the mechanical properties of die cast AZ91D magnesium alloy

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Journal of Magnesium and Alloys 2022年第7期10卷 1981-1993页

作者： Mengwu Wu Yingying Hou Lin Hua Huijuan Ma Xiaobo Li Shoumei Xiong Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

Both a conventional flow distributer and an improved one with a flow buffer were applied respectively during the high pressure die casting(HPDC)process,and samples of AZ91D magnesium alloy with different microstructure mainly consisting ofα-Mg grains,β-phase and porosities were *** to the grain orientation analysis,the predominant deformation behavior inα-Mg grains was dislocation slip,supplemented by deformation *** slip was more difficult to occur in the samples with the improved flow distributer on account of the fact that the size ofα-Mg grains in the microstructure was finer and more *** the in situ tensile deformation test,cracks were observed to initiate from gas-shrinkage pore and island-shrinkage,and two main crack propagation mechanisms,porosity growth and coalescence were found *** the crack was in contact with theβ-phase,it would pass through and fracture the networkβ-phase,whereas bypass the islandβ-phase by detaching it from the surroundingα-Mg *** property tests showed that the samples with relatively more homogeneous microstructure would perform higher mechanical properties,which was the combined effect of matrixα-Mg grains,β-phase,and porosities.

关键词： Magnesium alloy High pressure die casting Microstructure Deformation behavior Mechanical properties

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Homogeneity of microstructure and Vickers hardness in cold closed-die forged spur-bevel gear of 20Cr Mn Ti alloy

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Journal of Central South University 2015年第5期22卷 1595-1605页

作者：董丽颖兰箭庄武豪 School of Materials Science and Engineering Wuhan University of Technology School of Automotive Engineering Hubei Key Laboratory of Advanced Technology of Automotive PartsWuhan University of Technology

Cold closed-die forging is a suitable process to produce spur-bevel gears due to its advantages, such as saving materials and time, reducing costs, increasing die life and improving the quality of the product. The homogeneity of microstructure of cold closed-die forged gears can highly affect their service performance. The homogeneity of microstructure and Vickers hardness in cold closed-die forged gear of 20 Cr Mn Ti alloy is comprehensively studied by using optical microscopy and Vickers hardness tester. The results show that the distribution homogeneity of the aspect ratio of grain and Vickers hardness is the same. In the circumferential direction of the gear tooth, the distribution of the aspect ratio of grain and Vickers hardness is inhomogeneous and they gradually decrease from the surface to the center of the tooth. In the radial direction, the distribution of the aspect ratio of grain and Vickers hardness is inhomogeneous on the surface of the gear tooth; while it is relatively homogeneous in the center of the gear tooth. In the axial direction of the gear tooth, the distribution of the aspect ratio of grain and Vickers hardness is relatively homogeneous from the small-end to the large-end of the gear tooth.

关键词： cold closed-die forging 20Cr Mn Ti alloy microstructure Vickers hardness

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A method of generating car sounds based on granular synthesis algorithm

Noise Control Engineering Journal

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Noise Control Engineering Journal 2022年第4期70卷 384-393页

作者： Xie, Liping Lu, Chihua Liu, Zhien Zhu, Yawei Song, Weizhi Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan528200 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China

The active sound generation technique for automobiles, where car sounds can be synthesized by means of electronic sound production, is one of the effective methods to achieve the target sound. A method for active sound generation of automobile based on the granular synthesis algorithm is put forward here to avoid the broadband beating phenomena that occur due to the mismatch of parameters of sound granular signals. The comparison of the function expression of sound signal and Hilbert transformation is performed based on the principle of overlap and add;moreover, those parameters (phase, frequency and amplitude) of sound signals are interpolated by means of the Hermite interpolation algorithm which can ensure the continuity of the phase, frequency and amplitude curves. Thus, the transition audio is constructed by means of the sound signal function here to splice the adjacent sound granules. Our simulations show that our method can be applied to solve the current broadband beating issue for splicing sound granules and achieve natural continuity of synthesized car sounds. The subjective test results also indicate that our transition audio can produce high quality audio restitution. © 2022 Institute of Noise Control Engineering.

关键词： Granulation

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Effects of Electric and Magnetic Treatments on Microstructures of Solid Metals: A Review

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Chinese Journal of Mechanical Engineering 2023年第6期36卷 1-21页

作者： Yanli Song Wenlin Wu Yongqing Yu Lin Hua Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430070China School of Automotive Engineering Wuhan University of TechnologyWuhan 430070China Hubei Research Center for New Energy&Intelligent Connected Vehicle Wuhan University of TechnologyWuhan 430070China

An external electric or magnetic field can transfer high-intensity energy directly to the electronic scale of materials,and change the spin,energy level arrangement and trajectory of *** changes produce tremendous and profound impacts on the microstructure and mechanical properties of metal materials,which may be impos-sible with traditional *** paper reviews the effects of electric or magnetic field on the microstruc-tures of solid metals including phase transformation,precipitation,recrystallization,dislocations and so *** on the existing research results,the mechanisms of these effects have been ***,some typical applications of electric and magnetic treatments on solid metals have been described and the challenges in this field have also been discussed.

关键词： Electric field Magnetic field Microstructures Mechanical properties Solid metals

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Control Strategy Research of a Selective Catalytic Reduction System for Heavy-Duty Application

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Journal of Shanghai Jiaotong university(Science) 2017年第5期22卷 577-588页

作者：王天田林峰胡杰柯于强张岳秋 Hubei Key Laboratory of Advanced Technology for Automotive Components & Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Dongfeng Liuzhou Motor Co. Ltd. Beijing Municipal Vehicle Emission Management Center

An AdBlue dosing control strategy of the selective catalytic reduction (SCR) system is developed for a heavy-duty diesel (HDD) engine. The strategy includes a raw emission prediction model, an ammonia (NH3) coverage prediction model, a transient heat hysteresis correction algorithm, an NH3 leakage control model for transient operation conditions, and a feedback controller (FBC). FBC has been developed by using mathematical manipulation to change output signal of sensor based on cross-sensitivity of nitrogen oxide (NOx) sensor to NH3. The quantification of control parameters is based on experiments and Nyquist stability criterion. FBC is enabled in most test conditions to satisfy the stability requirements. NOxconversion (DeNOx) efficiency of SCR system is 82.4% in European steady-state cycle (ESC) test and 80.3% in European transient cycle (ETC) test, while the leakage of NH3 is under 10−5volume fraction in average. © 2017, Shanghai Jiaotong University and Springer-Verlag GmbH Germany.

关键词： Nitrogen oxides Stability criteria

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Numerical and experimental study on failure behavior of steel-aluminium mechanical clinched joints under multiple test conditions

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International Journal of Lightweight Materials and Manufacture 2019年第1期2卷 72-79页

作者： Song, Yanli Yang, Lulu Zhu, Genpeng Hua, Lin Liu, Runze Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of Technology Wuhan430070 China School of Automotive Engineering Wuhan University of Technology Wuhan430070 China

In this work, the numerical and experimental study was performed to explore the mechanical properties and failure behavior of steel-aluminium mechanical clinched joints under multiple test conditions. The stress distribution of the clinched joints and the failure mode were analyzed using finite element analysis software ABAQUS. The Gurson-Tvergaard-Needleman (GTN) model was used to simulate damage and failure of the joints. The experimental tests were conducted for the verification. It was found that the clinched joints under shear condition had a peak force of 4354N, which was much higher than that of the peel (624N) and cross tensile (1046N) conditions, while the peak load displacement and failure displacement have the opposite law. The failure mode of shear condition was neck fracture, while that of tensile and peel conditions were both pulling out failure. The finite element simulation results were in good agreement with the experimental ones and the failure mode was consistent. The Gurson-tvergaard-Needleman (GTN) model can accurately predict the mechanical properties and failure mode of clinched joints. © 2018 The Authors

关键词： Failure modes

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Joining Performance and Microstructure of the 2024/7075 Aluminium Alloys Welded Joints by Vaporizing Foil Actuator Welding

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Journal of Wuhan University of technology(Materials Science) 2019年第2期34卷 368-372页

作者：孟正华 WANG Xu GUO Wei HU Zhili Anupam Vivek HUA Lin Glenn S DAEHN Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Department of Materials Science and Engineering The Ohio State University

Vaporizing foil actuator welding(VFAW) was used for joining 2024-T3 and 7075-T6 aluminum alloy sheets, and the resulting joint microstructure was analyzed. 2024/7075 aluminum alloy pairs with suitable processing parameters can be prepared by using VFAW. Dynamic preform addresses the poor formability problem of target material and advantage of VFAW on dissimilar materials in some conditions. But with standoff sheet inserting in the flyer and target, 2024/7075 welded pairs gets the better weld strength, compared with flyer preformed method. The microstructure of the circular weld area of the welded joint showed a wave interface, in which a thin melt layer formed at the center and edge parts. The crystal grains near the bonding interface were remarkably elongated and refined. Therefore, the joining of the 2024/7075 pairs was facilitated through plastic forming and melting.

关键词： impact welding dissimilar materials vaporizing foil actuator joining interface

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