不同燃料柴油机多环芳烃排放特征的试验研究

在一台直喷式柴油机上,采用玻璃纤维滤纸及XAD-2吸附管采集、超声和索氏提取、气质联用分析等技术,测量了燃用柴油、生物柴油及其调合油B50排气中的多环芳烃类污染物（PAHs）.研究表明,柴油机颗粒相PAHs排放随着负荷的增大呈现降低的趋势,气相PAHs排放随着负荷呈现先降低后升高的趋势.与柴油相比,生物柴油的颗粒相和气...     

Effects of continuously regenerating diesel particulate filters on regulated emissions and number-size distribution of particles emitted from a diesel engine

The effects of continuously regenerating diesel particulate filter (CRDPF) systems on regulated gaseous emissions, and number-size distribution and mass of particles emanated from a diesel engine have been investigated in this study. Two CRDPF units (CRDPF-1 and CRDPF-2) with di erent specifications were separately retrofitted to the engine running with European steady-state cycle (ESC). An electrical low pressure impactor (ELPI) was used for particle number-size distribution measurement and mass estimation. The conversion/reduction rate (RCR) of hydrocarbons (HC) and carbon monoxide (CO) across CRDPF-1 was 83% and 96.3%, respectively. Similarly, the RCR of HC and CO and across CRDPF-2 was 91.8% and 99.1%, respectively. The number concentration of particles and their concentration peaks; nuclei mode, accumulation mode and total particles; and particle mass were highly reduced with the CRDPF units. The nuclei mode particles at downstream of CRDPF-1 and CRDPF-2 decreased by 99.9% to 100% and 97.8% to 99.8% respectively; and the particle mass reduced by 73% to 92.2% and 35.3% to 72.4%, respectively, depending on the engine conditions. In addition, nuclei mode particles increased with the increasing of engine speed due to the heterogeneous nucleation initiated by the higher exhaust temperature, while accumulation mode particles were higher at higher loads due to the decrease in the air-to-fuel ratio (A/F) at higher loads.     

缸内直喷汽油发动机电子装备振动环境试验的标准化和要点

对缸内直喷汽油发动机上装用的电子装备振动环境试验标准化过程和要点作了介绍.也列举了一些验证中可能产生影响的因素.供产品标准制修订和实验室在设计试验时参考.     

基于GIS的灾害应急管理系统业务数据和空间数据的集成

常用的关系数据库缺乏直接管理空间数据的成熟的通用方案。借助于空间数据库引擎(SDE)技术,扩展了关系数据库功能,使关系数据库成为业务数据和空间数据的统一存储管理平台,并在此基础上建立了基于Geodatabase模型的灾害应急管理系统数据库,对系统数据整体结构进行研究设计,解决了空间数据和业务数据的关联问题,实现了灾害应急管理系统空间数据和业务数据的无缝集成和一体化存储。该方法已在省级应急管理信息示范平台上成功应用。     

La0.7Sr0.3Mn1-xCoxO3-δ催化剂降低天然气发动机尾气排放的研究

采用喷雾热分解法制备了钙钛矿型催化剂La0.7Sr0.3Mn1-xCoxO3-δ(x=0、0.3、0.5、0.7),利用X射线衍射(XRD)和扫描电子显微镜(SEM)对催化剂进行了表征,在微型固定床反应器上优化了催化剂的B位掺杂Co.在天然气发动机排放试验台架上进行了空燃比特性、CH4排放和发动机尾气排放达标等测试试验.结果表明:在La0.7Sr0.3Mn1-x Co x O3-δ中掺杂适宜量的Co有助于提高催化剂的催化燃烧活性,改善催化剂比表面积和孔容积.当Co掺杂量为0.5时,所形成的La0.7Sr0.3Mn0.5Co0.5O3-δ催化剂对天然气发动机尾气排放物呈现出良好低温催化燃烧活性,对甲烷催化燃烧的起燃温度(T10)、半转化温度(T50)和完全转化温度(T90)分别为175、350和400℃,CO、NO x、非甲烷碳氢化合物(NMHC)和CH4的最大比排放量分别为3.01、1.72、0.31和0.85 g·kW-1·h-1,达到了国Ⅴ排放法规对天然气发动机有害排放物的限值要求,表明了La0.7Sr0.3Mn0.5Co0.5O3-δ适宜用于天然气发动机尾气低温催化燃烧的催化剂.     

氧化催化转化器对甲醇压燃尾气中甲醛排放的影响

在一台经过改装的压燃式发动机上,采用柴油/甲醇组合燃烧(DMCC)模式进行了台架实验,利用气相色谱分析技术检测了1800r·min<'-1时发动机尾气中甲醛的排放特性,对比研究了负荷、甲醇掺烧比、排气温度.催化转化器对甲醛排放的影响.研究结果表明,在压燃式发动机上采用DMCC模式,低负荷运行时,尾气中甲醛含量随甲醇掺烧比的增加而增多,在甲醇掺烧比为46%时.甲醛排放量达到180 x 10<'-6(体积分数),催化后可以减少25%～45%;在中,高负荷运行时.甲醛排放量随甲醇掺烧比的变化基本不变,高负荷比中负荷运行时甲醛排放稍高.但尾气经催化处理后,甲醛排放反而增加,最高增加1倍.催化转化器的转化效果与排气温度密切相关,当排气温度在大约300°C以下时,催化转化器可以降低甲醛排放量;当温度为300°C～410°C时,催化后尾气中的甲醛排放较催化前有所增加;当排气温度高于425°C时.催化后尾气中甲醛排放显著减少.     

基于ISO 26262的甲醇/柴油喷射控制系统功能安全概念开发

为提高甲醇/柴油双燃料发动机的安全性和可靠性,基于ISO 26262功能安全标准,定义甲醇/柴油喷射控制系统相关项,分析系统结构和功能;参照DFMEA分析方法,构造出相关项失效模型,得到系统功能失效导致的整车级危害;分析在最坏潜在事故场景下,危害事件的严重度、暴露率、可控性等级,得到汽车安全完整性等级,确立安全目标;提出系统功能安全要求,根据分解规则,将功能安全要求分配到系统各要素当中去,确立安全机制;在Isograph软件中搭建FTA故障树模型,评估系统硬件随机失效指标与安全目标一致性,验证功能安全概念。结果表明:利用功能安全概念更新系统架构,评估各个要素失效率和安全机制诊断覆盖率后,系统随机硬件失效指标为9.405E-09/h,符合ASILD等级安全要求。     

Quantification of emission variability for off-road equipment in China based on real-world measurements

• Emissions from 53 in-use diesel-fueled off-road equipment were measured. • There exists a large off-road equipment variability in emissions. • Engine operations have significant impacts on real-world tailpipe emissions. • Emission inventory development should take into account job duties and operations. The objective of this paper is to quantify the variability in emissions of off-road equipment using a portable emission measurement system. A total of 53 commonly used equipment for agriculture, base construction, paving construction, and material handling were selected. Time-based and fuel-based emissions were quantified by different duty and engine modes. Three duty modes (idling, moving, and working) were used. Ten engine modes were defined based on normalized engine revolutions-per-minute and manifold absolute pressure, respectively. Composite emission factors taking into account both duty modes and its corresponding time percentage during a typical duty cycle were estimated. Results showed that there existed a large off-road equipment variability in emissions. Depending on duty and engine modes, time-based NO emissions ranged from 3.1 to 237.9, 29.1‒1475.6, 83.2‒681.6, and 3.2‒385.2 g/h for agriculture, base construction, paving construction and material handling equipment, respectively while for fuel-based NO emissions these ranges were 5.3‒52.0, 11.7‒69.0, 4.8‒30.8, and 11.0‒54.6 g/kg, respectively. Furthermore, emission factors derived from this study exhibited a much larger variability compared to those used in NONROAD by US EPA and National Guideline for Off-road Equipment of China. This implied that localized measurements of emissions are needed for improvement of accuracy of emission inventory. Furthermore, both equipment types and operations should be considered for development of emission inventory and control strategy.     

车辆冷却系统高原热平衡性能研究

目的 分析海拔高度(大气压力)、环境温度、冷却液温度以及冷却风量等对车辆冷却系统高原散热性能的影响.方法 采用模拟试验与仿真相结合的方法 .结果 海拔升高1000 m,发动机水套散热量平均增加约5.3％;冷却液温度升高10℃,发动机水套散热量平均降低约14.5％;海拔升高1000 m,若保持发动机热平衡状态不变(出口冷...