Fuel consumption of fuel cell hybrid vehicles considering battery SOC differences

Fuel cell hybrid vehicles (FCHVs) have become one of the most promising candidates for future transportation due to current energy supply problem and environmental problem. Fuel economy is an important factor in FCHVs. In order to properly evaluate the fuel economy of an FCHV, the initial battery state of charge (SOC) and the final battery SOC have to be identical so that the effect of the battery energy usage on the fuel economy is neglected. In the simulation or in the real driving, however, the final battery SOC is usually different from the initial battery SOC, and the final battery SOC often depends on the power management strategy. To consider the difference between the two battery SOC values, the concept of equivalent fuel consumption is presented by two methods. One is based on the relationship between delta SOC and delta fuel consumption, and the other is based on the optimal control theory. Two rule-based power management strategies for an FCHV are presented, and for each strategy, the fuel economy is evaluated based on the two methods. The characteristics of the two methods are discussed and compared, and the superior one is selected based on the comparison.     

New lead-acid battery management system based on generator regulation

A novel regulation system for a vehicle generator and lead-acid battery is proposed in this paper. By integrating the regulation method, the output voltage of the generator is determined and controlled by the algorithm to save electrical energy and protect the lead-acid battery. The regulation algorithm is implemented in Matlab/Simulink, and the logic function of the system is verified using the dSPACE/AutoBox workbench. The experimental results show that the new algorithm improves the performance of the fuel economy of the vehicle and the battery state-of-health compared to the traditional control method.     

Course stability and yaw motion of a ship in steady wind

In order to achieve safe navigation, it is important to be able to understand and calculate the effects of an external force on the maneuvering behavior of a ship. This paper analyzes the course stability and yaw motion of a ship traveling under steady wind conditions. A course stability criterion and approximate formulae for the yaw motion in steady wind, including the aero/hydrodynamic force derivatives for the ship, are derived. To confirm the reliability of the criterion and formulae, they were used to investigate a pure car carrier in steady wind. The results of this investigation revealed that course instability appears in the head and following wind directions, mainly under the influence of aerodynamic derivatives with respect to the yaw restoring forces. However, this course instability can be reduced by applying steering control. For winds ranging from head winds to beam winds, yaw oscillation appears when the period is relatively long and the damping is small. The analytical formulae derived here can be used to gain a better understanding of ship maneuvering behavior in steady wind.     

New method for predicting full-scale power performance of pumpjet propulsion system based on statistical learning北大核心CSCD

[目的]针对“适配于螺旋桨的船尾线型+泵喷推进器”构成的船舶泵喷推进系统,提出一种基于统计学习的实船快速性预报新方法。[方法]以某大型水面船舶泵喷推进系统为对象,通过神经网络学习典型推进泵的推力系数图谱曲线,综合运用船-桨配合时的K_(T)-J曲线和船体-喷泵配合时的推力特性曲线,建立“仅需船舶阻力曲线就能实现船舶泵喷推进系统实船快速性预报”的新方法,并基于船模阻力试验、泵喷模型敞水试验及船体-泵喷自航试验的测量换算结果对实船推进性能的预报结果开展精度校验。[结果]校验结果表明:在航速18~30 kn范围内,船舶泵喷推进系统的自航转速、推力和功率的预报误差可控制在5.4%以内,其中设计航速附近的误差甚至小于2%;船体-泵喷的相互作用程度介于船-桨与船体-喷泵之间且幅值相对较小,推力减额系数为趋向于0的极小值,故船舶泵喷推进系统是介于桨轴推进系统和喷水推进系统之间的产物。[结论]该预报方法有利于提升船舶泵喷推进系统实船快速性预报的能力,可为新型舰艇泵类推进系统总体设计/研究提供参考。     

A citation network analysis of sustainability development in liner shipping management: a review of the literature and policy implications

ABSTRACT

Based on an analysis of 253 related papers drawn from the Web of Science database, this study examines holistic sustainability research in liner shipping management literature using a citation network analysis (CNA) approach followed by a qualitative analysis of findings. We identify four major research domains, namely shipping performance, port selection and management, shipping markets, and environment, as well as related sub-domains of shipping performance. We discuss the current research trends and focal issues in these domains with a focus on their implications for policy development. Our results indicate that while the sustainability discourse in the literature has developed and matured significantly over the last decade, generating valuable insights for practitioners and regulators alike, it still struggles with blurry terminology and a lack of holistic frameworks jointly addressing the different aspects of sustainability: Economic considerations of liner shipping are still the main concern, while environmental and social issues are less regarded in the academic discourse. Furthermore, we identify a dearth of studies rooted in managerial or economic theory. In this regard, our study provides insights on the scope of the holistic sustainability discourse in liner shipping management, its contributions to theory and practice, and its implications for the further development of policies addressing sustainability in liner shipping management. We advocate further construct development for sustainability in liner shipping, as well as empirical tests of the antecedents of sustainability practice adoption in the industry for future research.     

Fault diagnosis of marine diesel engine intake and exhaust system based on dynamic feature fusion北大核心CSCD

[目的]船舶系统由多设备的复杂机构组成,各组件参数具有动态性和非线性的特点,所以故障诊断过程复杂。为提高诊断效率,提出一种动态特征融合方法。[方法]利用分形理论、动态理论及核主元分析(KPCA)法对系统状态数据进行重构、映射及筛选,得到主元特征数据矩阵,求得平方预测误差(SPE)及相应的控制限,构建出基于船舶柴油机进排气系统健康数据的离线监测模型,利用该模型对系统进行故障诊断分析。为验证模型的有效性,选取某船舶柴油机进排气系统的故障数据进行验证分析。[结果]结果表明,动态特征融合分析方法可有效实现对系统动态非线性状态数据的精确分析,实现对系统故障的高效分析和诊断。与KPCA及支持向量机(SVM)方法相比,所提方法具有更好的故障诊断性能。[结论]该方法可实现船舶柴油机进排气系统故障的检测和诊断,提升系统运行的可靠性和安全性。     

盾构隧道整体道床剥离病害规律研究北大核心CSCD

盾构隧道整体道床的剥离病害已严重影响地铁的安全运营。为研究整体道床剥离病害的规律,文章以国内某运营地铁线路为工程背景,建立整体道床-管片-注浆层数值模型进行分析研究。结果表明:列车轮组作用在道床一侧靠近伸缩缝位置时会引起较大的道床剥离变形,是最不利位置;列车荷载在振动作用下引起的剥离量远大于静载作用时的,且两者间存在函数关系;伸缩缝位置是最易发生剥离的区域,剥离首先发生在伸缩缝两侧边缘,随列车动载作用时间增加,剥离区域扩展至伸缩缝1.5 m范围内;注浆层刚度与接触面黏结强度均是影响剥离量的重要因素,提升注浆层刚度和道床-管片接触面的黏结强度可有效减少剥离量。     

襄阳汉江沉管隧道设计关键技术北大核心CSCD

基于襄阳汉江沉管隧道的工程设计实践,针对该隧道强冲刷、强透水地层深厚、防洪要求高等特点,对隧道平纵布置、管节及接头止水结构、干坞选型及结构、沉管基础及回填、沉管最终接头及对接端止水结构等进行了研究。结果表明:(1)内河沉管隧道采用长距离双轴线干坞布置方式,通过格形地下连续墙、超深落底式帷幕、地下连续墙预应力锚索垂直支护和混凝土封底组合技术解决了强透水地层深基坑支护及隔水难题;(2)采用全断面顺浇技术进行整体式管节预制,实现了管节接头止水设施的全国产化;(3)在内河沉管隧道采用高精度浮式整平先铺卵石基础,并提出了强冲刷区管顶防冲保护解决方案;(4)采用了不设独立止推构造的陆域最终接头,并针对工程需求设置了大直径锁口钢管桩配合外侧止水墙的对接端支护结构及分片整体吊装双壁钢围堰二次止水结构。     

Application of interval Multi-attribute Decision-Making Method to Aeroengine Performance Ranking

Introduction The performance deterioration of aeroengine isone of the key factors which may induce aircraft cata-strophic events. With the expansion of airline fleets,the number of aeroengines increase dramatically.Because performance parameters can refle…     

厚壁球壳的杂交／混合有限元分析

本文对８一节点四边形轴对称杂交／混合元ＡＸＨＭ１６进行了系列考核：（１）考查ＡＸＨＭ１６是否含有零能变形模式，以查明它的含秩状况；（２）通过受内压作用的厚壁球壳考题，观察ＡＸＨＭ１６的转轴不变性和其它性能表现。事实表明：ＡＸＨＭ１６满足单元合理足秩的必要条件和充分条件，不含零能变形模式，单刚合足秩。数值考核表明：ＡＸＨＭ１６具有很好的位移精度和应力精度，对坐标转轴的敏感程度并不明显，且在近乎相同的