汽油车技术发展对尾气排放影响研究进展

近年来，汽油车尾气排放已成为城市大气污染的主要来源之一.为减少油耗、温室气体和大气污染物的排放，汽油直喷技术(GDI)、醇类燃料替代以及混合动力系统等新兴技术被应用到汽车产品中，该研究对GDI发动机汽车、醇类燃料车和混合动力车的颗粒物(PM)、氮氧化物(NO_x)、总碳氢化合物(THC)的排放研究进行梳理和总结，综合评估先进动力技术和醇类燃料的环境影响.结果表明:GDI汽油车的PM排放因子为进气道喷射(PFI)汽油车的1.2~5倍，加装汽油颗粒物捕集器(GPF)后GDI汽油车的PM排放大幅下降，同时具备催化能力的GPF可减少NO_x和THC排放.与汽油车相比，乙醇燃料车PM排放量减少了35%~56%，尾气THC排放减少了10%~44%，但挥发性有机物(VOCs)蒸发排放增加了20%~41%，其主要来自于日呼吸损失.各类型车辆的NO_x排放差异较小，比较结果存在一定的不确定性.混合动力车相比传统内燃机汽车污染物减排优势明显，可积极推广其在公共交通和私家车队中的应用.建议今后研究应着重关注以下几个方面:①GDI和混合动力车在实际条件下排放污染物的环境影响；②醇类燃料车VOCs蒸发排放控制技术及相关法规标准的完善；③新兴技术汽油车排放污染物的生成机理及其影响因素. 

Research Progress on Impact of Gasoline Vehicles Technology Development on Exhaust Emission

In the current era, exhaust emissions of gasoline vehicles have become one of the primary sources of urban air pollution. The latest technologies such as gasoline direct fuel injection (GDI), alcohol fuels and hybrid power systems are being used in automotive products to reduce petroleum consumption so that emissions of greenhouse gases and other pollutants can be minimized in the environment. In this paper, particulate matter (PM), nitrogen oxide (NO_x) and total hydrocarbon (THC) emissions from GDI engine vehicles, alcohol fuel vehicles and hybrid electric vehicles were summarized. Furthermore, the environmental impact of advanced power technologies and alcohol fuels were comprehensively evaluated. The results show that the PM emission factor of GDI vehicles was 1.2-5 times that of port fuel injection (PFI) vehicles. After the addition of gasoline particulate filter (GPF), the PM emission decreased significantly, and the catalytic GPF reduced the NO_x and THC emissions. Compared with gasoline, the PM emissions of alcohol fuel decreased by 35%-56%, and the NO_x emission factor was similar to that of gasoline. Compared with gasoline, the THC from exhaust emission reduced by 10%-44%, but volatile organic compounds (VOCs) from evaporative emissions increased by 20%-41% mainly due to diurnal breathing loss. The differences in NO_x emission of different types of vehicles were small, and there was a certain degree of uncertainty in the comparison results. For reduction of pollution, hybrid electric vehicles show obvious advantages over the traditional vehicles, so that their promotion in public and private transportation is recommended. The following research subjects are urgently needed:(1) The environmental impact of pollutants emitted by GDI and hybrid electrical vehicles under actual conditions. (2) The improvement of VOCs evaporation emission control technology and relevant regulations and standards for alcohol fuel vehicles. (3) The impacts and formation mechanism of pollutant emission from emerging technology vehicles.