Fuel economy comparison of conventional drive trains series and parallel hybrid electric step vans

A hybrid electric vehicle (HEV) is a vehicle that combines a conventional propulsion system with an on-board rechargeable energy storage system to achieve better fuel economy than a conventional vehicle HEVs do not have limited ranges like battery electric vehicles, which use batteries charged by an external source. The different propulsion power systems may have common subsystems or components. The objective of this study is to compare the fuel economies of a conventional step van, a series hybrid electric step van (HESV), and a parallel HESV by calculating the fuel consumption using the ADVISOR software by NREL. We also showed the results of the vehicles in different driving cycles including the Central Business District bus cycles, the New York City Cycle, and the US EPA City and Highway cycles.     

Experimental studies on low pressure semi-direct fuel injection in a two stroke spark ignition engine

In this work a two-stroke scooter engine was modified to work with semi-direct injection of gasoline at a pressure of 8 bar from an injector in the cylinder barrel pointed toward the cylinder head. The influence of injection timing, injection pressure, spark plug location and air-fuel ratio, on performance, emissions and combustion characteristics has been investigated. In addition, a comparison has been made with manifold injection of gasoline on the same engine at a given speed and various outputs. A significant reduction in HC emissions and fuel consumption with no adverse effects on NOx emissions and combustion stability was observed. A small drop in power and increase in CO emission were observed disadvantages of the new injection system. Injection timing was found to be the most important factor and a balance between reduction in shortcircuited fuel by late injection, and time for mixture preparation by advancing the injection, was found to be essential.     

管道技术

全世界正在以前所未有的速度消耗着石油和天然气,因此,需要以成本效益的方式开发新的资源。然而,最近管道设计公司面临更具挑战性的海上和海底环境,从而需要采取新的方式来克服不寻常的设计挑战     

Flutter and Divergence Instabilities in Systems of Railway Wheelsets with Semi-rigid Articulation

For railway vehicles having coned wheels mounted on solid axles there is, in general, a conflict between stability of lateral deviations from the motion along the track and ability to steer round curves. However, certain configurations of three-axle vehicle can satisfy the requirement of perfect curving and for certain values of the system parameters are dynamically stable. In the case where three wheelsets have semi-rigid articulation and either the distribution of conicity amongst the wheelsets or the position of the articulation joint are varied, it is shown that both flutter and divergence instabilities can occur at low speeds, in contrast to the more common dynamic instabilities of other forms of railway vehicle which are driven by the inertia forces.     

一种最佳的汽车混合动力总成

介绍了对混合动力总成进行优化的建模及仿真工具《汽车快速性能优化及报告工具包—汽车系统模块(RAPTOR^TM—VSM)软件包》，指出了优化混合动力总成需在混合动力发动机、电动机、电池、超级电容器、动力总成配置和自动／手动变速器(AMT)控制器等方面做的工作。     

工厂火灾,爆炸场所危险度综合评价法

为减少火灾事故，介绍了“工厂火灾、爆炸场所危险度综合评价法”，“道氏法”是该法的基础。分析了“道氏法”的不足，而提出了固定危险和现实补偿的综合性计算方法。还通过实例记述了新方法的优点、基本原理和应用方法。该法能用于评价工厂企业危险设备、装置与场所的火灾、爆炸危险程度。     

不同外加剂对OGFC混合料路用性能的影响

OGFC为开级配沥青混合料,主要由粗集料嵌挤组成,在世界各地越来越广泛地用于铺筑路面.OGFC混合料可以增大路表面渗透性,减少噪音,增强表面摩擦力,尤其是在潮湿条件下.该文主要研究不同外加剂对OGFC路用性能的影响,其混合料分别由再生聚乙烯改性沥青(RPEB)、橡胶粉改性沥青(CRMB)和70#基质沥青+纤维与矿料拌和而成.并分别采用析漏试验、肯塔堡飞散试验、渗水试验、劈裂试验、静态模量试验,车辙试验和抗滑试验评估OGFC混合料的路用性能.结果表明:纤维和聚合物可以有效地减小OGFC离析的可能性,混合料每面击实50次能相应地提高磨耗性和其他相关的性能.改性沥青混合料的抗拉强度比(TSR)低于纤维+基质沥青混合料的抗拉强度比.     

The Geometrical Contact between Track and Wheelset

In previous publications the author has described a so-called first-order theory for the motion of a railway vehicle wheelset on a tangent track. In the present report the geometrical aspect of this theory is further evaluated and a method for solving the constraint equations between the coordinates of the wheelset is indicated.