奥迪轿车人为故障一例

故障现象：一辆大众原装奥迪200轿车,装备V6电控直喷式汽油机（发动机排量为2．6L）,自动变速器。该车在我厂进行发动机大修后一直不能起动,经检查没有高压电,断定为点火模块损坏,但更换点火模块后发动机仍不能起动。     

Influence on the hydrodynamic performance of a variable vector propeller of different rules of pitch angle change

To design a more effective blade pitch adjustment mechanism,research was done on changes to the hydrodynamic characteristics of VVPs(Variable Vector Propeller) caused by different rules for changing pitch angle. A mathematical method for predicting the hydrodynamic characteristics of a VVP under unsteady conditions is presented based on the panel method. Mathematical models for evaluation based on potential flow theory and the Green theorem are also presented. The hydrodynamic characteristics are numerically predicted. To avoid gaps between panels,hyperboloidal quadrilateral panels were used. The pressure Kutta condition on the trailing edge of the VVP blade was satisfied by the Newton-Raphson iterative procedure. The influence coefficients of the panels were calculated by Morino's analytical formulations to improve numerical calculation speed,and the method developed by Yanagizawa was used to eliminate the point singularity on derivation calculus while determining the velocities on propeller surfaces. The calculation results show that it's best for the hydrodynamic characteristics of the VVP that pitch angle changes follow the sine rule.     

自主水下航行器变浮力系统研究现状及控制技术

变浮力系统（VBS）在自主水下航行器（AUV）上的应用极大地提高了AUV的操纵性能、续航能力、对环境变化的适应能力以及完成多种任务的能力。AUV种类繁多,配置的VBS也各不相同,有必要深入研究AUV的变浮力系统及其控制技术。首先,针对AUV不同类型VBS的原理和特点进行详细说明,并总结其适用场景;然后,对VBS在AUV操纵控制上的典型应用进行介绍,包括均衡、悬停以及着陆、坐底等;接着,对变浮力AUV现有的浮力调节技术、浮力观测技术以及协同操控技术进行综述与评价;最后,对变浮力AUV的发展前景进行展望。     

“双碳”目标下国家中心城市绿色交通水平评价方法

为衡量国家中心城市绿色交通水平,探寻了制约其绿色交通发展的关键因素,以制定针对性的发展策略,推动交通运输领域“双碳”目标的实现。首先,根据国家中心城市绿色交通系统的特点,采用驱动力-压力-状态-影响-响应（Driver-Pressure-State-Impact-Response, DPSIR）模型构建国家中心城市绿色交通水平评价指标体系。然后,分别采用直觉模糊层次分析法（Intuitionistic Fuzzy Analytic Hierarchy Process, IFAHP）和熵权法确定评价指标的主、客观权重,并借鉴博弈论思想提出评价指标的综合赋权方法。之后,采用改进的集对分析-可变模糊集耦合模型评价国家中心城市绿色交通水平。最后,引入障碍度模型识别限制国家中心城市绿色交通发展的关键因素和制约类型。结果表明：2020年9个国家中心城市绿色交通均属于“一般”水平,呈现出“边高中低”的空间分布特征;日均轨道交通客运量占城市人口比重、交通干线噪声平均值、节能环保支出占财政支出比重、人均GDP和交通运输支出占财政支出比重是制约国家中心城市绿色交通水平的关键因素。     

发动机内的魔术可变进气歧管技术

前两期我们把发动机可变气门正时技术与大家交流了一番,这次我们将把影响发动机性能的另一大因素——进气系统大卸八块展示给我们的读者。[编者按]