某船冰机起停频繁原因分析

介绍了某船冰机起停频繁的故障现象、原因分析及排除方法。     

船舶在纵倾状态下稳性的粗略计算法

对初稳性高度GM的通常求法是先根据本船平均吃水,以此查静水力曲线图,再据一系列公式求得,在船舶吃水差不大的情况下,此方法计算出的GM与实际GM接近,当船舶吃水差很大,计算GM可能与实际GM有较大出入,这对船舶的安全可能是不利的。文章从求稳性最原始方法入手,采用较粗略的方法提出了船舶在较大的纵倾状态下船舶初稳性高度计算和相关曲线图绘制的方法。     

锚杆静压桩处理一项目地基实例

通过具体的工程实例,介绍了承载力锚杆静压桩在一项目的应用,详细介绍了锚杆静压桩施工技术。     

烃类添加剂改善M100甲醇发动机冷起动的试验研究

针对M 100甲醇发动机在低温环境下起动困难的问题,在M 100甲醇中添加烃类添加剂,改善甲醇发动机的低温起动性能.按体积比在M 100甲醇中分别添加15%汽油、8.5%异戊烷、10%石油醚作为添加剂,采用试验的方法测量了-20℃,-10℃,0℃三种环境温度下,甲醇发动机的起动性能.结果表明:甲醇中添加15%的汽油、8.5%的异戊烷、10%的石油醚,-20℃时M 100甲醇发动机可以正常起动,起动时间小于3.5 s,在-10℃时起动时间小于2.5s,在0℃时起动时间小于1.5s;环境温度为-10℃时,增大首循环喷射脉宽有利于缩短起动时间,首循环喷射脉宽从110 m s增大到130 m s,添加上述比例添加剂后,M 100甲醇发动机的起动时间分别缩短0.2s,0.2s,0.05s.     

埋地燃气管道带压开孔技术应用

埋地管道铺建时预留的分支管道接口不合适,需要在管道带压正常运行的状态下进行开孔施工.介绍了埋地燃气管道带压开孔技术的专用设备组成、操作方法、步骤和技术要点.实践证明:这项带压开孔技术的应用会更加广泛.     

Measurement of hydrocarbon and carbon monoxide emissions during the starting of automotive DI Diesel engines

Most of hydrocarbon (HC) and carbon monoxide (CO) emissions from automotive DI Diesel engines are produced during the engine warm-up period and are primarily caused by difficulties in obtaining stable and efficient combustion under these conditions. Furthermore, the contribution of engine starting to these emissions is not negligible; since this operating condition is highly unfavorable for the combustion progress. Additionally, the catalytic converter is ineffective due to the low engine temperature. In conjunction with adequate engine settings (fuel injection and fresh air control), either the glow plugs or the intake air heater are activated during a portion of the engine warm-up period, so that a nominal engine temperatures is reached faster, and the impact of these difficulties is minimized. Measurement of gaseous pollutants during engine warm-up is currently possible with detectors used in standard exhaust gas analyzers (EGA), which have response times well-suited for sampling at such transient conditions. However, these devices are not suitable for the measurement of exhaust emissions produced during extremely short time intervals, such as engine starting. Herein, we present a methodology for the measurement of the cumulative pollutant emissions during the starting phase of passenger car DI Diesel engines, with the goal of overcoming this limitation by taking advantage of standard detectors. In the proposed method, a warm canister is filled with an exhaust gas sample at constant volumetric flow, during a time period that depends on the engine starting time; the gas concentration in the canister is later evaluated with a standard EGA. When compared with direct pollutant measurements performed with a state-of-art EGA, the proposed procedure was found to be more sensitive to combustion changes and provided more reliable data.     

西安地铁渗漏水原因及应对措施

地铁工程大多处于地下水位附近及以下,因此做好地铁防水显得尤为重要。以西安地铁2号线一期工程为背景,在详细调查研究车站、暗挖隧道、盾构隧道渗漏水现状和特点的基础上,重点从外包防水、施工缝、诱导缝、变形缝和混凝土裂缝等方面分析渗漏水原因并提出应对措施,就地铁防水设计和施工中需要注意的问题进行讨论。     

电厂用柴油发电机组的电气控制

针对电厂用柴油发电机组应急、快速启动、可靠性高的特点,结合实际调试应用中遇到的问题,依据技术协议要求,提出一种功能要求全面的典型设计思路,为今后电厂用柴油发电机组的电气控制设计提供一定的依据。     

西安北站综合交通枢纽信息集成管理平台研究

根据西安铁路枢纽规划,西安北站将成为西安市的一个综合交通枢纽。为了实现枢纽内运营资源的协调一致和效能最大化,很有必要从综合交通枢纽的高度建立一个统一的管理信息系统平台。文章从西安北站搭建这么一个管理信息系统平台的需求着手,分析了系统平台的功能和实现技术;并着重探讨了信息集成的手段,主要包括信息集成的服务功能需求和总体结构;然后,从理论上构造了一个西安北站综合交通枢纽信息集成管理平台的总体体系架构,并分析指出了该平台的作用。     

控制电路故障导致康明斯柴油机无法启动的分析与排除

康明斯柴油机的控制电路出现问题经常会引起柴油机不能启动,在分析柴油机控制电路基础上,结合启动机运转情况给出柴油机不能启动故障诊断流程图,依次对直流供电系统、转速传感器、执行器和转速控制器进行检查,查找故障点,通过调整和更换相关元件排除柴油机无法启动的故障。