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为研究同时运用废气再循环(EGR)技术和燃用生物柴油对柴油机排气颗粒纳米结构的影响,分别采集0%,15%,30%EGR率下186F柴油机燃用生物柴油时的排气颗粒,并用激光拉曼光谱仪测得颗粒光谱,使用五带法对一阶拉曼光谱进行拟合,分析拟合曲线参数,计算颗粒微晶尺寸和碳碳键长度。结果表明:EGR率为30%时,生物柴油颗粒光谱的半高宽(FWHM)最大,代表化学异相性最强并且颗粒中的物质种类最多,随着EGR率降低,半高宽逐渐减小;当EGR率从0%升高到30%,ID/IG逐渐增大,代表石墨化程度降低,颗粒中的石墨结构减少;同时,ID1/ID2从0%EGR率的8左右降低到15%和30%EGR率的4左右,代表EGR率升高,颗粒内部缺陷由空位缺陷向石墨烯边缘缺陷发展;随着EGR率升高,微晶尺寸逐渐减小,碳碳键长度基本不变。
In order to study the influence of exhaust gas recirculation (EGR) technology and biodiesel on diesel engine exhaust particle nanostructures, exhaust particles of 186F diesel engine with biodiesel at 0%, 15% and 30% , And the particle spectra were measured by laser Raman spectroscopy. The first-order Raman spectra were fitted by the five-band method. The fitting curve parameters were analyzed to calculate the crystallite size and carbon-carbon bond length. The results show that when the EGR rate is 30%, the FWHM of the biodiesel particle spectrum is the largest, which indicates the strongest chemical heterogeneity and the largest species in the particles. As the EGR rate decreases, the full width at half maximum decreases. When the EGR rate increases from 0% to 30%, the ID / IG increases gradually, which means the degree of graphitization decreases and the graphite structure in the particles decreases. Meanwhile, the ID1 / ID2 decreases from about 8% at 0% EGR rate to 15% 30% EGR rate of about 4, on behalf of the EGR rate increased, the internal defects within the particle defect from graphene edge defects development; with the EGR rate increases, the crystallite size decreases, the carbon-carbon bond length substantially unchanged.