轻型汽油车实际行驶污染物排放的影响因素

为了研究车辆冷起动、行程动力学参数和不同数据处理方法对实际行驶排放(RDE)试验的影响,本文利用4辆轻型汽油车进行试验研究,通过CO2移动平均窗口法和欧6新方法进行排放计算。结果表明:冷起动对CO和NOx排放影响偏差均在10%以内,对于未装配汽油机颗粒捕集器(GPF)车辆的市区PN排放影响偏差最大可达32.25%,在国6车型标定时应重点关注。相对正向加速度(RPA)与PN排放成正相关,与CO、NOx排放相关性不明显;v*apos,95(速度与正向加速度乘积按升序排序的第95个百分位取值)与CO、PN排放成正相关,与NOx排放成负相关,与CO和PN的相关系数大于与NOx的相关系数。对于同一个有效行程的污染物排放计算结果,欧6新方法大于CO2移动平均窗口法,欧6新方法能更加真实地反映车辆在RDE试验中的污染物排放水平。     

汽油车低温冷起动和常温冷起动排放特性的对比分析

针对国Ⅲ标准中新规定的-7°的低温冷起动测试,采用对比试验的方法比较了低温冷起动(Ⅵ型试验)和常温冷起动(Ⅰ型试验)整个排放过程中CO、HC和CO2的排放差异。对两种温度条件下的催化器入口温度进行了比较分析。通过对排放特性的比较,简述了汽油车低温冷起动排放控制方法。     

2018年世界船舶市场评述与2019年展望

回顾了2018年世界经济、航运、造船市场,并对2019年进行展望。2018年世界经济平稳复苏,航运市场整体趋势向好,新船订单吨位量小幅上升;2019年世界经济风险偏于下行,航运市场将在压力中前行,各细分市场"几家欢喜几家愁",世界新造船市场呈现弱复苏态势,绿色和智能是市场增长的主要动力来源。     

怠速空气温控阀在摩托车上的应用

将怠速空气温控阀应用在骑式和弯梁摩托车上时,可大大提高摩托车的冷机起动、过渡和加速性能,摩托车发动机和化油器结构设计改动较小,成本增加也少,很值得在骑式和弯梁摩托车上推广使用。     

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。     

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.     

系泊船舶在不规则波中慢漂振荡的马尔可夫模型

一艘在非高斯慢漂波浪力激励下的系泊船舶的响应被用一个连续的马尔可夫过程来建模.提出了一个数值路径积分解法来计算该艘船舶的响应统计.该数值路径积分法是基于Gauss-Legendre插值方案,响应概率密度值是在子区间内的高斯分点上获得的.显示该数值路径积分解法有独特的能力在很低概率水平时生成精确解,这在系统可靠性分析时有重要意义.     

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.     

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。