缸内直喷汽油车颗粒物数量及可溶性有机组分排放特性

以一辆国V排放缸内直喷汽油车为研究对象,试验研究了NEDC、FTP-75和WLTC对该车颗粒物质量、23nm~2.5μm固态颗粒物数量、5.6~560nm超细颗粒数量及粒径分布、颗粒物有机组分的影响.结果表明：NEDC、FTP-75、WLTC颗粒粒径分布基本相同,均呈对数双峰分布,在9nm和60nm两个粒径处出现峰值;5.6~23nm颗粒物数量排放占5.6~560nm颗粒物数量的43.1%~57.7%;与NEDC比较,加减速比例高、瞬态性强的FTP-75、WLTC循环的颗粒物质量、23nm~2.5μm固态颗粒数量、5.6~560nm颗粒数量排放增大;缸内直喷汽油车的颗粒物可溶性有机物组分占颗粒物的20.5%~27.9%,可溶性有机物主要为C16和C18的脂肪酸、C20~C29烷径和5环以上的高分子量多环芳烃,测试循环对颗粒SOF排放及组分产生影响,瞬态性强的FTP-75、WLTC的PAHs比例增加.     

怠速起停对汽油车油耗及颗粒数量排放的影响

以一辆配置怠速起停系统的国V缸内直喷汽油车为研究对象,使用底盘测功机试验系统、全流稀释采样系统和固态颗粒计数系统,试验研究怠速起停对缸内直喷汽油车油耗与颗粒数量排放的影响,并分析起动温度、试验循环等因素的影响.结果表明,NEDC循环车辆冷机起动时,车辆怠速起停系统开启的百公里油耗降低了5.1%,颗粒数量排放升高了16.7%;车辆热机起动,怠速起停开启产生的百公里油耗降幅增大到7.3%,颗粒数量排放升幅减小至9.3%;WLTC循环热机起动,车辆怠速起停系统开启的百公里油耗降幅减少到1.7%,颗粒数量排放升幅减少到6.2%.怠速起停有利于降低汽车的百公里油耗,但不利于缸内直喷汽油车颗粒数量排放的控制.     

汽油轿车NEDC循环超细颗粒物排放特性

以一辆采用电控燃油进气道多点喷射系统的桑塔纳汽油轿车为试验样车,采用排气颗粒数量及粒径分析仪EEPS,对该车NEDC循环的超细颗粒排放数量及颗粒粒径分布特性进行了试验研究.结果表明,NEDC循环中,车辆加速时排放的核模态颗粒、聚集态颗粒数量浓度均增加;车辆启动后40 s及EUDC循环高速工况（≥90 km.h-1）排放的超细颗粒数量浓度较高;NEDC循环的颗粒数量排放呈单峰对数分布,颗粒数量排放峰值的颗粒粒径集中于10～30 nm,几何平均粒径为24 nm;ECEⅠ、ECEⅡ～Ⅳ和EUDC循环,加速、减速、怠速及匀速驾驶工况的颗粒数量排放基本上呈单峰对数分布,颗粒数量排放峰值的颗粒粒径主要集中于10～30 nm,几何平均粒径集中于14～42 nm.该汽油车NEDC循环排放的超细颗粒主要以粒径小于50 nm的核模态颗粒为主.     

DOC+CDPF对国III重型柴油货车实际道路排放的影响

利用便携式车载排放测试系统（PEMS）对2辆加装氧化催化转化器（DOC）和催化型柴油颗粒捕集器（CDPF）与否的国III重型柴油货车进行实际道路排放测试.结果表明,2辆改造重型柴油车的CO、THC、固态颗粒物粒数（SPN）和黑碳（BC）实际道路排放因子分别为（1.31±0.37）g/（kW×h）、（0.20±0.03） g/（kW×h）、（7.13×10¹⁰±5.27×10¹⁰）个/（kW×h）和（0.69±0.06）mg/（kW×h）,相对于原始排放（拆除DOC+CDPF）分别降低52.48%、55.69%、99.91%和99.22%.从低速、中速到高速,CO和THC减排比例呈现上升趋势,然而运行工况对SPN和BC减排比例则无显著影响.加装DOC+CDPF会导致NO₂在NO_x中的占比升高,且从低速、中速到高速涨幅依次增大,但对NO_x无明显减排效益,其排放因子为9.53~9.83g/（kW×h）,远高于实验室排放限值.     

法规工况下轻型汽油车氨排放特征

为掌握轻型汽油车NH₃排放实际状况,以一辆配备三元催化转化器(three-way catalytic converter,TWC)的国Ⅵ轻型汽油车为研究对象,分别在全球轻型汽车驾驶工况(worldwide light-duty test cycle,WLTC)、中国轻型汽车行驶工况(China light-duty vehicle test cycle,CLTC)和美国联邦测试规程(federal test procedure,FTP-75)下进行NH₃排放测试,分析WLTC工况下的瞬时NH₃排放特征,以及不同环境温度(?7、0、23、35 ℃)对NH₃排放的影响,并对比3种测试工况下的NH₃排放因子. 结果表明:①在WLTC工况下,车辆冷起动前50 s未检测到NH₃,NH₃排放主要集中在低速段和中速段(前900 s),在高速段和超高速段,仅有极少量的NH₃生成. 轻型汽油车在低速(v<40 km/h)的加速区间内,NH₃排放量较高. ②随着环境温度的升高,NH₃排放因子呈下降趋势,35 ℃时略微有所上升. 其中,?7 ℃下低速段的NH₃排放因子分别是0、23和35 ℃下的1.4~2.2倍;在WLTC工况下,各种测试环境温度下车辆的NH₃排放因子均表现为低速段>中速段>高速段>超高速段;在3种工况下,轻型汽油车的NH₃排放因子差异较大. 其中,测试车辆在WLTC工况下的排放因子最小. 研究显示,在低温(?7 ℃)环境下轻型汽油车NH₃的排放量相对较高.      

进料浓度对鸡粪长期高温甲烷发酵的影响

通过固定水力停留时间（HRT）为20d,逐步提高进料总固体（TS）浓度为5.0%,7.5%和10.0%的方式提高有机负荷（OLR）,在高温（55±1）℃条件下开展鸡粪长期甲烷发酵实验并测定了各阶段污泥的比产甲烷活性（SMA）,探究氨氮浓度对鸡粪高温甲烷发酵的影响.结果显示,当进料TS由5.0%增至10.0%,出料氨氮浓度由（2.5±0.3）g/L增至（6.1±0.2）g/L,挥发性脂肪酸（VFAs）由（0.4±0.1）g/L增至（26.1±1.5）g/L,pH值由（8.3±0.2）降至（6.9±0.1）,产气率由（267.2±12.5）mL/g TS_in降至49.8±8.2mL/g TS_in,甲烷浓度由（67.2±1.3）%降至（36.0±1.7）%.长时间采用TS 10.0%的进料浓度,发酵系统中氨氮浓度最高达到7.5g/L,VFAs浓度达到27.0g/L,产气下降明显.氨氮抑制鸡粪高温甲烷发酵产气的初始浓度为2.5~3.0g/L.进料TS大于7.5%,鸡粪高温甲烷发酵会受到氨氮抑制.氨氮浓度的升高导致高温发酵体系利用乙酸产甲烷的能力降低,氨氮浓度达到5.5g/L,SMA降低60.0%;氨氮浓度达到7.0g/L,污泥利用乙酸产甲烷的活动几乎停止.     

曝气策略调控CANON工艺降温降基质稳定运行

通过调整曝气策略,研究了降温降基质（氨氮）运行过程中实现全程自养脱氮（CANON）序批式生物膜反应器（SBBR）稳定运行的可行性.结果表明,在中温（35℃）高基质[（446.47±43.77）mg NH₄⁺-N/L]曝气/停曝=60min/60min条件下,反应器稳定运行223d,总氮去除负荷（TNRR）和总氮去除率（TNRE）分别为（0.49±0.07）kg N/（m³·d）和（84.3±4.6）%.温度降至20~23℃,根据一个运行周期内NO₂^--N积累速率和去除速率之比调整曝气工况为曝气/停曝=40min/80min,运行69d后TNRR和TNRE分别降至（0.43±0.04）kg N/（m³·d）和（69.5±5.7）%.而后逐步梯度降低基质至（105.6±16.1）mg NH₄⁺-N/L,采用相同策略分别调整曝气/停曝时间为40min/80min、30min/90min和8min/32min,运行93d后TNRR降至（0.16±0.02）kg N/（m³·d）,TNRE升至（71.5±7.5）%.高通量测序结果从群落组成角度证实了降温和降基质过程中实施的曝气调控策略维持了CANON系统脱氮功能菌的主导地位,亚硝酸盐氧化菌NOB相对丰度一直被控制在0.1%以下.     

北京上甸子大气本底站氢氟碳化物在线观测研究

在北京上甸子区域大气本底站利用气相色谱/质谱联用（GC-MS）系统对大气中11种氢氟碳化物（HFCs）开展在线观测研究.2018年1~12月,HFC-23、HFC-32、HFC-125、HFC-134a、HFC-143a、HFC-152a、HFC-227ea、HFC-236fa、HFC-245fa、HFC-365mfc、HFC-4310mee本底数据浓度分别为：（31.9±0.4）×10^-12、（22.1±1.7）×10^-12、（29.3±1.3）×10^-12、（110.2±2.4）×10^-12、（24.0±0.3）×10^-12、（10.3±0.7）×10^-12、（1.59±0.04）×10^-12、（0.19±0.01）×10^-12、（3.30±0.08）×10^-12、（1.27±0.03）×10^-12、（0.28±0.01）×10^-12;本底数据出现频率分别为：34.5%、23.4%、22.5%、24.6%、24.5%、42.5%、24.3%、46.4%、38.3%、68.1%、77.9%;非本底数据浓度分别为：（39.2±11.1）×10^-12、（47.7±21.8）×10^-12、（38.6±8.7）×10^-12、（137.3±15.7）×10^-12、（26.1±2.2）×10^-12、（15.9±7.0）×10^-12、（2.77±1.11）×10^-12、（0.25±0.06）×10^-12、（4.10±0.97）×10^-12、（1.34±0.06）×10^-12、（0.30±0.01）×10^-12.HFC-32、HFC-125、HFC-134a、HFC-143a、HFC-227ea本底浓度呈线性上升趋势,年增长率分别为：4.4×10^-12,3.8×10^-12,7.3×10^-12,1.0×10^-12,0.14×10^-12a^-1,而HFC-152a呈现明显的季节变化.以CO为示踪物利用示踪物比值相关法估算了HFC-23、HFC-32、HFC-125、HFC-143a、HFC-152a、HFC-236fa、HFC-245fa排放量,分别为6.4,17,14,27,4.0,0.10,1.3kt/a.     

满足国六排放的缸内直喷汽油车污染物排放特性试验研究

以满足国六排放的某缸内直喷轻型汽油车为研究对象,试验研究了该车国六Ⅰ型测试循环(WLTC循环)排放的CO、THC、NOx和固态颗粒数量,以及包含挥发性/半挥发性组分的颗粒物数量和粒径分布特性.结果表明:WLTC循环工况覆盖范围广、车速高、加速度大的特点导致污染物排放增加;车辆冷机起动、暖机过程、瞬态过渡工况和高速大负荷工况对车辆的污染物排放影响较大,研发合理的车辆起动、催化剂起燃和暖机热管理策略、提高发动机瞬态过渡工况响应性是控制排放的重点;包含挥发性/半挥发性组分的颗粒物数量排放呈单峰分布,在15 nm附近达到峰值.     

机动车轮胎磨损颗粒物化学组分特征研究

为研究机动车道路行驶过程中轮胎磨损排放的颗粒物理化特性,利用轮胎轮廓仿真磨耗仪,对国内主流17种轮胎胎面进行仿真磨耗实验,获得颗粒物样品,提取并检测其中18种元素和20种多环芳烃（PAHs）的含量.结果显示,元素和PAHs含量因轮胎品牌和速度等级的不同而差异显著.18种元素平均含量为（99.04±68.43）mg/g,占样品总重的9.90%,其中Si（88.97±67.85）mg/g、Zn（6.77±1.64）mg/g和Na（1.05±0.75）mg/g的平均含量均超过1mg/g,Cd的含量最低,为（0.43±0.31）μg/g.20种PAHs含量之和（∑20PAHs）在12.13~433.64 μg/g,平均为（94.13±110.18）μg/g,PY的平均含量最高（30.98±31.27）μg/g,其次是CHR、BaP、FA、PHE和BghiP,平均含量最低的是AC（0.58±0.2）μg/g;从环数看,以4环PAHs为主（占∑20PAHs的45.03%~67.93%）,其次为3环（平均含量为15.45%）和5环（平均含量为12.62%）.总体来说,国外品牌轮胎样品中元素和PAHs含量略高于国内品牌,而主要PAHs环数略低于国内品牌.     

Influence of driving cycles on exhaust emissions and fuel consumption of gasoline passenger car in Bangkok

The influence of different driving cycles on their exhaust emissions and fuel consumption rate of gasoline passenger car was investigated in Bangkok based on the actual measurements obtained from a test vehicle driving on a standard chassis dynamometer. A newly established Bangkok driving cycle (BDC) and the European driving cycle (EDC) which is presently adopted as the legislative cycle for testing automobiles registered in Thailand were used. The newly developed BDC is constructed using the driving characteristic data obtained from the real on-road driving tests along selected traffic routes. A method for selecting appropriate road routes for real driving tests is also introduced. Variations of keyed driving parameters of BDC with different driving cycles were discussed. The results showed that the HC and CO emission factors of BDC are almost two and four times greater than those of EDC, respectively. Although the difference in the NOx emission factor is small, the value from BDC is still greater than that of EDC by 10%. Under BDC, the test vehicle consumes fuel about 25% more than it does under EDC. All these differences are mainly attributed to the greater proportion of idle periods and higher fluctuations of vehicle speed in the BDC cycle. This result indicated that the exhausted emissions and fuel consumption of vehicles obtained from tests under the legislative modal-type driving cycle (EDC) are significantly different from those actually produced under real traffic conditions especially during peak periods.     

Real-world vehicle emission factors in Chinese metropolis city--Beijing

The dynamometer tests with different driving cycles and the real-world tests are presented. Results indicated the pollutants emission factors and fuel consumption factor with ECE15 EUDC driving cycle usually take the lowest value and with real wodd driving cycle occur the highest value, and different driving cycles will lead to significantly different vehicle emission factors with the same vehicle. Relative to the ECE15 EUDC driving cycle, the increasing rate of pollutant emission factors of CO, NOx and HC are - 0.42--2.99, - 0.32--0.81 and - 0.11--11 with FTP75 testing, 0.11--1.29, - 0.77--0.64 and 0.47--10.50 with Beijing 1997 testing and 0.25--1.83, 0.09--0.75 and - 0.58--1.50 with real wodd testing. Compared to the carburetor vehicles, the retrofit and MPI TWC vehicles‘ pollution emission factors decrease with different degree. The retrofit vehicle (Santana) will reduce 4.44%--58.44% CO, - 4.95%--36.79% NOx, -32.32%--33.89% HC, and -9.39%--14.29% fuel consumption, and especially that the MPI TWC vehicle will decrease CO by 82.48%--91.76%, NOx by 44.87%--92.79%, HC by 90.00%--93.89% and fuel consumption by 5.44%--10.55%. Vehicles can cause pollution at a very high rate when operated in high power modes; however, they may not often operate in these high power modes. In analyzing vehicle emissions, it describes the fraction of time that vehicles operate in various power modes. In Beijing, vehicles spend 90% of their operation in low power modes or decelerating.     

基于车载诊断系统的轻型乘用车实际道路油耗特征分析

近年来的一系列研究表明,轻型车实际道路油耗与型式认证油耗间的差异在不断增大,之前的实际道路油耗研究大多基于用户上报数据或车载排放测试系统(PEMS).车载诊断系统(OBD)是一种监测发动机及排放控制系统实时工作状态的仪器.本研究通过OBD解码器采集瞬时发动机进气量计算机动车瞬态油耗并通过2辆轻型汽油车的实验室台架测试证明该方法具有很好的准确性(差异在±5%以内).本研究进一步在北京选取了7辆轻型汽油车,利用OBD解码器开展实际道路油耗测试,并研究运行工况及车辆载重对其实际道路油耗的影响.实际道路结果显示测试车辆在典型工况下的油耗比型式认证油耗高23.1%~46.4%,平均差异为29.2%.通过微观运行模态方法将实际道路油耗修正到法规测试循环(NEDC工况)的交通特征下,道路油耗仍然比型式认证油耗高18.7%±7.1%.研究表明,平均速度与实际道路油耗具有很强的相关性.实际道路油耗在30 km·h-1以下时会随速度降低而显著上升.此外,研究还发现如果车辆载重增加260 kg,实际道路油耗将上升6.2%±2.2%.     

Variability of fuel consumption and CO2 emissions of a gasoline passenger car under multiple in-laboratory and on-road testing conditions

An increasing divergence regarding fuel consumption(and/or CO₂ emissions) between realworld and type-approval values for light-duty gasoline vehicles(LDGVs) has posed severe challenges to mitigating greenhouse gases(GHGs) and achieving carbon emissions peak and neutrality. To address this divergence issue, laboratory test cycles with more real-featured and transient traffic patterns have been developed recently, for example, the China Lightduty Vehicle Test Cycle for Passenger cars(CL...     

Modeling and predicting low-speed vehicle emissions as a function of driving kinematics

An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system (PEMS) under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics (speed and acceleration) of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data.     

Optimization of gasoline hydrocarbon compositions for reducing exhaust emissions

Effects of hydrocarbon compositions on raw exhaust emissions and combustion processes were studied on an engine test bench. The optimization of gasoline hydrocarbon composition was discussed. As olefins content increased from 10.0% to 25.0% in volume, the combustion duration was shortened by about 2 degree crank angle ( CA), and the engine-out THC emission was reduced by about 15%. On the other hand, as aromatics content changed from 35.0% to 45.0%, the engine-out NOx emissions increased by 4%. An increment in olefins content resulted in a slight increase in engine-out CO emission, while the aromatics content had little e ect on engine-out total hydrocarbon (THC) and CO emissions. Over the new European driving cycle (NEDC), the THC, NOx and CO emissions of fuel with 25.0% olefins and 35.0% aromatics were about 45%, 21% and 19% lower than those of fuel with 10.0% olefins and 40.0% aromatics, respectively. The optimized gasoline compositions for new engines and new vehicles have low aromatics and high olefins contents.     

纯电动汽车驱动电机全生命周期评价

基于生命周期评价(LCA)理论,运用Ga Bi 6软件建模,对荣威E50纯电动汽车驱动电机全生命周期环境排放和资源消耗进行了评价,对比分析在中国不同区域使用下驱动电机生命周期过程资源环境影响,并对驱动电机生命周期过程中的生产制造能耗、使用能耗和原材料回收率做敏感性分析.结果表明,驱动电机全生命周期过程各环境影响类型指数排序为APGWPPOCPEPODP,且对环境的影响主要发生在使用阶段,其次是原材料获取和制造阶段.各大区域电网下驱动电机全生命周期过程环境排放影响从大到小为华东电网东北电网西北电网华北电网南方电网华中电网.从敏感性分析结果可知,使用能耗对驱动电机生命周期环境排放影响的敏感度大于生产制造能耗;铜的回收率对矿产资源消耗影响的敏感度远大于钢和铝的回收率.