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Influence of periodic pressure on dendritic morphology and sidebranching

China Foundry 2020年第4期17卷 279-285页

作者： Shan Shang Zhi-peng Guo Zhi-qiang Han Xin-yu Zhang Yi-nuo Cheng Jun Li State Key Laboratory of automotive Safety and Energy Tsinghua UniversityBeijing 100084China School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China HiRain technologies Co. Ltd.Beijing 100191China

The influence of periodic pressure with low and high frequencies on microstructure and dendritic sidebranching was studied by using 3-D phase field method. In both low and high frequency cases, the variation trend of SDAS (secondary dendritic arm spacing) with increasing pressure frequency is opposite to that of sidebranching frequency, while the variation trend of the average length of secondary arms is consistent with that of sidebranching frequency. The high sidebranching frequency indicates that more secondary arms share the whole driving force of dendrite growth, resulting in lower driving force for each one and leading to less developed secondary arms. The smallest SDAS is obtained when perturbed by the periodic pressure with the frequency of 0.157/τ0 (τ0 is the physical unit of time in the dimensionless phase field model) and 2.200/τ0 in low and high frequency cases, respectively. Comparisons of dendritic morphology and secondary arms are made between the low and high frequency cases. Firstly, in the low frequency case, secondary arms are luxuriant especially when pressure frequency is low, with many high-order side branches stretching out. Secondly, the average length of secondary arms in primary dendrite is longer in the low frequency case than that without pressure, and much longer than that in the high frequency case. Thirdly, the dendrite tip without side branches in the high frequency case is much longer than that in the low frequency case. All of the differences in dendritic morphology and sidebranching in the two cases can be attributed to the different modulation mechanism. In the low frequency case, periodic pressure determines tip velocity and then modulates sidebranching directly. While in the high frequency case, periodic pressure cannot determine sidebranching directly, but via modulating tiny protuberances in dendrite tip, part of which evolves into side branch. In this case, the tiny protuberances take part of the whole driving force, leading

关键词： periodic pressure dendritic morphology SDAS phase field method

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Carbody Structural Lightweighting Based on Implicit Parameterized Model

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Chinese Journal of Mechanical Engineering 2014年第3期27卷 483-487页

作者： CHEN Xin MA Fangwu WANG Dengfeng XIE Chen State Key Laboratory of automotive Simulation and Control Jilin University Zhejiang Geely Automobile Research Institute Co. Ltd

Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher costs. Also, material substitution and processing lightweighting have to be realized through body structural profiles and locations. In the huge conventional workload of lightweight optimization, model modifications involve heavy manual work, and it always leads to a large number of iteration calculations. As a new technique in carbody lightweighting, the implicit parameterization is used to optimize the carbody structure to improve the materials utilization rate in this paper. The implicit parameterized structural modeling enables the use of automatic modification and rapid multidisciplinary design optimization （MDO） in carbody structure, which is impossible in the traditional structure finite element method （FEM） without parameterization. The structural SFE parameterized model is built in accordance with the car structural FE model in concept development stage, and it is validated by some structural performance data. The validated SFE structural parameterized model can be used to generate rapidly and automatically FE model and evaluate different design variables group in the integrated MDO loop. The lightweighting result of body-in-white （BIW） after the optimization rounds reveals that the implicit parameterized model makes automatic MDO feasible and can significantly improve the computational efficiency of carbody structural lightweighting. This paper proposes the integrated method of implicit parameterized model and MDO, which has the obvious practical advantage and industrial significance in the carbody structural lightweighting design.

关键词： carbody structural lightweighting implicit parameterization MDO BIW

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Predictive safety control for road vehicles after a tire blowout

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Science China(Information Sciences) 2018年第7期61卷 101-103页

作者： Fei WANG Hong CHEN Lulu GUO Yunfeng HU State Key Laboratory of automotive Simulation and Control Jilin University Department of Control Science and Engineering Jilin University

Since driver error is considered a major cause in over 90%of all road crashes[1],driving assistance systems are widely used to improve driving safety,and are an important research direction in the intelligent vehicle *** the rapid development of sensing,identification and communication technologies,the vehicle can obtain an increasing amount of information in real time,ranging from the vehicle status information to road information

关键词： Predictive safety control for road vehicles after a tire blowout

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Vibration analysis and control technologies of hydraulic pipeline system in aircraft:A review

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Chinese Journal of Aeronautics 2021年第4期34卷 83-114页

作者： Peixin GAO Tao YU Yuanlin ZHANG Jiao WANG Jingyu ZHAI School of Electromechanical and automotive Engineering Yantai UniversityYantai 264005China School of Mechanical Engineering Dalian University of TechnologyDalian 116024China

Vibrations in aircraft hydraulic pipeline system,due to multi-source excitation of high fluid pressure fluctuation and serious vibration environment of airframe,can cause the pipeline system vibration failures through overload in engineering *** the vibrations in hydraulic pipeline is a challenging work to ensure the flight safety of *** common vibration control technologies have been demonstrated to be effective in typical structures such as aerospace structures,shipbuilding structures,marine offshore structures,motor structures,***,there are few research literatures on vibration control strategies of aircraft hydraulic *** with the development trend of aircraft hydraulic pipeline system and the requirement of vibration control technologies,this paper provides a detailed review on the current vibration control technologies in hydraulic pipeline system.A review of the general approaches following the passive and active control technologies are presented,which are including optimal layout technique of pipeline and clamps,constrained layer damping technique,vibration absorber technique,hydraulic hose technique,optimal pump structure technique,and active vibration control technique of pipeline ***,some suggestions for the application of vibration control technologies in engineering field are given.

关键词： Aircraft Hydraulic pipeline Vibration analysis Vibration control Vibration failure

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Study on the Electric Actuation of Liquid Metal Column in Confining ystem

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Chinese Journal of Mechanical Engineering 2022年第3期 221-224页

作者： Shuting Liang Zengwei Wang Fengjiao Li Mengjun Huang Ge Ding China College of Chemical and Environmental Engineering Chongqing University of Arts and Sciences Chongqing Key Laboratory of Environmental Materials and Remediation technologies Chongqing University of Arts and Sciences Shenzhen automotive Research Institute Beijing Institute of Technology

Research on micro-machines is becoming popular. In this paper, the electric driving behavior of liquid metal columns in confining channel was studied. When the electric field was applied, the liquid metal near the negative electrode became flat, longer. The NaOH electrolyte(1.0 mol/L) could flow from the positive electrode to the negative electrode from a small space above the liquid metal column. Besides, the length and volume of the liquid metal would affect its motion and deformation behavior. Both cylindrical liquid column(R = 5 mm, L = 5 cm) and linear liquid column(R = 5 mm, L = 40 cm) exhibit deformable movements, which are similar to the bionic movements of earthworms. The electrically driven liquid metal in closed systems could provide a theoretical basis for droplet actuation in *** has a very wide application prospect in the field of micro-drive machines.

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Research on Green and Low-Carbon Development Path of China's automotive Industry

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Chinese Journal of Urban and Environmental Studies 2023年第1期11卷 66-82页

作者： ZHAO Dongchang ZHAO Mingnan SUN Xin ZHANG Hongjie LIU Huanran WU Jinlong LEI Zhenlu LI Jia’ang QIAN Bing LU Linfeng LIN Yu CHANG Wei China automotive Carbon Digital Technology Center Co. Ltd.

China’s automotive industry has been dedicated to a series of carbon-reduction efforts and has strived for comprehensive green and low-carbon transformation in order to achieve carbon peaking and carbon neutrality goals. On the basis of automobiles’ whole life-cycle(WLC) carbon emission accounting, this paper calculates life-cycle carbon emissions per vehicle, proposes green and low-carbon development path for China’s automotive industry, quantifies and analyzes implicated carbon-reduction potential, and puts forth suggestions for high-quality green and lowcarbon development of China’s automotive industry. The first is to establish a sound standard and data management system; the second is to promote research, development and application of lowcarbon materials and low-carbon technologies; the third is to accelerate the pace of fostering a new consumption model in the automotive industry. The research results can further support national policy-making regarding carbon emissions, promote corporations’ research, development and application of low-carbon technologies, encourage green and low-carbon consumption, and lead the automotive industry to achieve WLC neutrality.

关键词： Automobile life-cycle carbon emission low-carbon transformation

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Variability of fuel consumption and CO_(2) emissions of a gasoline passenger car under multiple in-laboratory and on-road testing conditions

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Journal of Environmental Sciences 2023年第3期125卷 266-276页

作者： Boya Zhou Liqiang He Shijian Zhang Rui Wang Luowei Zhang Mengliang Li Yu Liu Shaojun Zhang Ye Wu Jiming Hao China automotive Technology and Research Center Co. Ltd.Tianjin 300300China School of Environment State Key Joint Laboratory of Environment Simulation and Pollution ControlTsinghua UniversityBeijing 100084China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084China Beijing Laboratory of Environmental Frontier technologies School of EnvironmentTsinghua UniversityBeijing 100084China

An increasing divergence regarding fuel consumption(and/or CO_(2)emissions) between realworld and type-approval values for light-duty gasoline vehicles(LDGVs) has posed severe challenges to mitigating greenhouse gases(GHGs) and achieving carbon emissions peak and neutrality. To address this divergence issue, laboratory test cycles with more real-featured and transient traffic patterns have been developed recently, for example, the China Lightduty Vehicle Test Cycle for Passenger cars(CLTC-P). We collected fuel consumption and CO_(2)emissions data of a LDGV under various conditions based on laboratory chassis dynamometer and on-road tests. Laboratory results showed that both standard test cycles and setting methods of road load affected fuel consumption slightly, with variations of less than 4%. Compared to the type-approval value, laboratory and on-road fuel consumption of the tested LDGV over the CLTC-P increased by 9% and 34% under the reference condition(i.e., air conditioning off, automatic stop and start(STT) on and two passengers). On-road measurement results indicated that fuel consumption under the low-speed phase of the CLTC-P increased by 12% due to the STT off, although only a 4% increase on average over the entire cycle. More fuel consumption increases(52%) were attributed to air conditioning usage and full passenger capacity. Strong correlations(R2> 0.9) between relative fuel consumption and average speed were also identified. Under traffic congestion(average speed below 25 km/hr), fuel consumption was highly sensitive to changes in vehicle speed. Thus,we suggest that real-world driving conditions cannot be ignored when evaluating the fuel economy and GHGs reduction of LDGVs.

关键词： Fuel consumption CO_(2)emissions Light-duty gasoline vehicle(LDGV) Real driving

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A novel application of fluidization-Integrating three processes in reclaiming foundry sand

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Particuology 2010年第6期8卷 595-598页

作者： Derek Geldart Jim Lewis Powder Research Ltd Leeds University UK Coastal River technologies PLLC USA

Immersion of automotive parts in a fluidized bed of foundry sand is used to both strip the castings free from moulding sand and to heat-treat the castings at 500℃. The fluid bed is heated by hot gases from a burner directed first into a serpentine heat exchanger located near one side-wall of the rectangular tank, and then into a distributor consisting of horizontal sparger pipes having maintenance standpipes fixed into their upper surfaces.

关键词： Removal of moulding sand Castings Fluidized beds Heat transfer Foundries

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Key technologies for polymer electrolyte membrane fuel cell systems fueled impure hydrogen

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Progress in Natural Science:Materials International 2020年第6期30卷 751-763页

作者： Pucheng Pei Mingkai Wang Dongfang Chen Peng Ren Lu Zhang State Key Lab.of automotive Safety and Energy Tsinghua University School of Mechanical-Electronic and Vehicle Engineering Beijing University of Civil Engineering and Architecture

Hydrogen energy and polymer electrolyte membrane(PEM) fuel cells become concerned issues in recent ***, the construction of hydrogen refueling infrastructure and hydrogen storage and transportation constrains the commercial development of fuel cells. In this review, sources, production, storage, transportation,and purification methods of hydrogen are extensively reviewed and compared. The advantages of utilizing industrial by-product hydrogen and steam reforming gas in PEM fuel cell systems are analyzed. Using industrial wasted hydrogen can significantly reduce the cost of hydrogen. Also, it is indicated that the onboard hydrogen generation by steam methanol reforming can solve the difficulties of efficient storage and transportation of gaseous hydrogen, which means that methanol has great potential to be a convenient carrier of hydrogen. The effects of impurities contained in the reformate gas are generally introduced. After the methanol steam reforming and pretreatment purification processes, the reformate gas can be fed to PEM fuel cells. Thus, a fuel cell system integrated with onboard hydrogen production and impure hydrogen treatment subsystems is introduced,and key technologies therein for pretreatment purification and in-situ poisoning mitigation methods are reviewed. Finally, suggestions are proposed for further studies.

关键词： Polymer electrolyte membrane fuel cell system Hydrogen production and storage Steam methanol reforming Impure hydrogen Hydrogen purification

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Adoption of precision agriculture technologies in India and in some developing countries:Scope,present status and strategies

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Progress in Natural Science:Materials International 2009年第6期19卷 659-666页

作者： Pinaki Mondal Manisha Basu Department of Agricultural and Food Engineering Indian Institute of Technology International Centre for automotive Technology 3. National Research Development Corporation

Rapid socio-economic changes in some developing countries, including India, are creating new scopes for application of precision agriculture (PA). The implications of dramatic shifts for economic development, urbanization and energy consumption in some developing countries are immense. High-tech nature of traditional PA technologies developed in advanced countries created a real challenge for engineers to search suitable PA technologies for developing countries. It is expected that application of balanced soft and hard PA technologies based on the need of specific socio-economic condition of a country will make PA suitable for developing countries also. ‘Soft’ PA depends mainly on visual observation of crop and soil and management decision based on experience and intuition, rather than on statistical and scientific analysis. ‘Hard’ PA utilizes all modern technologies such as GPS, RS, and VRT. Three components, namely, ‘single PA technology’, ‘PA technology package’ (for the user to select one or combination) and ‘integrated PA technology’, have been identified as a part of adoption strategies of PA in the developing countries. Therefore, the objective of this paper is to find out the scope, the present status and the strategies for adoption of PA in India and in some developing countries. Application of PA in cash crop, plantation crop, etc. has been discussed. Application of some medium and low-tech PA tools such as chlorophyll meter and leaf colour chart. in small farms has been included. This exhaustive review of the present status of PA in India and in some developing countries is expected to help to find out the adoption trend and direction of future research. Detailed strategy for the adoption of PA in India has also been proposed.

关键词： Precision agriculture Indian agriculture Developing countries Adoption

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