Evaluation of the International Vehicle Emission （IVE） model with on-road remote sensing measurements

Intemational Vehicle Emissions （IVE） model funded by U.S. Environmental Protection Agency （USEPA） is designed to estimate emissions from motor vehicles in developing countries. In this study, the IVE model was evaluated by utilizing a dataset available from the remote sensing measurements on a large number of vehicles at five different sites in Hangzhou, China, in 2004 and 2005. Average fuel-based emission factors derived from the remote sensing measurements were compared with corresponding emission factors derived from IVE calculations for urban, hot stabilized condition. The results show a good agreement between the two methods for gasoline passenger cars＇ HC emission for all 1VE subsectors and technology classes. In the case of CO emissions, the modeled results were reasonably good, although systematically underestimate the emissions by almost 12%-50% for different technology classes. However, the model totally overestimated NOx emissions. The IVE NOx emission factors were 1.5-3.5 times of the remote sensing measured ones. The IVE model was also evaluated for light duty gasoline truck, heavy duty gasoline vehicles and motor cycles. A notable result was observed that the decrease in emissions from technology class State II to State I were overestimated by the IVE model compared to remote sensing measurements for all the three pollutants. Finally, in order to improve emission estimation, the adjusted base emission factors from local studies are strongly recommended to be used in the IVE model.     

HT240材料发动机缸体疲劳试验及性能分析

目的确定HT240材料发动机缸体疲劳寿命,从而验证其可靠性。方法参照AVL的缸体疲劳试验标准,根据该型发动机的爆发压力,选取一定安全裕度的脉动液压压力,在疲劳试验机上模拟实际工况对四件样品进行缸体脉冲加载试验。结果在缸体上部易出现裂缝。对缸套的实验数据进行处理,确定了其在运行一定次数下不发生破坏的条件疲劳极限为17.89MPa。同时明确了缸体主轴承壁在21MPa下未破坏的循环次数及其他破坏位置。结论该批次缸体基本满足设计要求。为该材料发动机缸体的批量生产及进一步优化设计提供了理论依据。     

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.     

电动与内燃机汽车的动力系统生命周期环境影响对比分析

以国内某两款同一车型的电动与内燃机汽车的动力系统为研究对象,通过生命周期分析软件GaBi建立生命周期评价(LCA)模型,在清单数据分析的基础上,采用CML2001模型对两种动力系统分别进行了定量的生命周期环境影响评价.评价结果表明,电动汽车动力系统的全生命周期综合环境影响比内燃机汽车动力系统高60.15％,并分别通过回收阶段分析、电能结构分析和敏感性分析对这一结果进行了解释:回收阶段中酸化、富营养化和光化学臭氧合成3种环境影响类型的直接排放大于回收得到的环境效益;电动汽车动力系统的环境影响随着火力发电比例的下降而减小,增大水能、风力和核能发电在电力系统中所占比例能有效降低电动汽车对环境的影响;动力系统重量对电动汽车动力系统的环境排放影响最为敏感,电池充电效率次之,制造阶段能耗的敏感度最小.将动力系统使用阶段的环境影响分配到整车,则电动汽车的生命周期环境影响比内燃机汽车低0.14％,且主要环境影响类型是全球变暖、酸化和富营养化.     

贵金属和助剂负载量对柴油公交车CDPF颗粒净化性能的影响

为研究CDPF(催化型颗粒捕集器)贵金属和助剂负载量对柴油公交车颗粒排放特性的影响,对一台满足国Ⅲ排放法规的柴油公交车进行改造,加装4种不同后处理装置,并进行道路实车排放试验.结果表明,CDPF贵金属负载量越高,排气颗粒数量浓度越低,在中高车速下尤为明显(60 km·h-1车速下贵金属负载量增加5 g·ft-3,颗粒排放总数降低70.8%).贵金属负载量对排放颗粒物中核态颗粒的影响大于聚集态颗粒.在保证对排气颗粒的净化效果的前提下,在CDPF中添加适量镧系助剂,可使贵金属和助剂负载量大幅降低.不同后处理方案对加速工况不敏感,净化效果差异较小,但减速工况,各方案对颗粒的净化效果差异较大.     

汽油机燃用乙醇和汽油的混合燃料的试验研究

对摩托车汽油机进行了燃用乙醇 汽油混合燃料的试验,并与燃用汽油时的结果进行了对比分析.结果显示,汽油机燃用乙醇和汽油的混合燃料,当混合燃料中乙醇比例为10%和15%时,即使发动机的结构不变、燃油系统和点火系统不作任何调整的时候,发动机的全负荷输出不受影响,发动机的能耗率得到改善,HC和CO排放有所降低,但是NOx排放会有显著增加.     

飞机发动机室内开车尾气排放引射喷淋降温仿真分析

目的将气候实验室飞机发动机开车时产生的高温高噪声尾气实时顺利排出室外,保持试验所需的稳定环境场,避免排气不畅或可能的高温尾气回流对试验及试验设施产生破坏,保证试验安全可靠进行。方法设计一套发动机开车尾气排放系统,对关键的气体引流喷淋降温进行CFD数值模拟。结果喷流环孔径、喷射角度及数量分布均直接影响引射喷淋雾化效果。结论获得可以满足发动机开车尾气排放塔出口温度分布的喷淋环参数,指导引流管喷淋环的详细设计。     

弹箭贮存寿命预测预报技术综述

概述了弹箭系统贮存寿命预测预报技术的研究现状及研究方法。对弹箭系统的橡胶构件、发射药、推进剂、固体发动机的贮存寿命预测预报技术进行了详细介绍。阐明了现有技术的优点及缺陷．并且表明针对不同的产品应选择适当的方法及条件才能得出相对比较可信的预估贮存寿命。     

柴油发电机环境低频噪声影响防治初探

以设在民用住宅里的柴油发电机环境低频噪声对环境的影响为研究对象,就柴油发电机环境低频噪声对环境敏感点的影响进行监测,了解民用住宅里的柴油发电机环境噪声对环境的影响水平,参照我国的国家标准作环境影响评价,探讨民用住宅里的柴油发电机环境低频噪声对环境的污染防治对策.     

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...