醇类燃料发动机排气管保温降低醇醛排放研究

摘要

The effects of exhaust pipe insulation on unregulated emissions of a spark ignition (SI) engine fueled with M10 (10％ of methanol in blend by volume) and E10 (10％ of ethanol in blend by volume) blends respectively were experimentally investigated with gas chromatography (equipped with a pulsed discharge helium ionization detector,PDHID).Experimental results show that methanol and ethanol emissions decreased after exhaust pipe heat insulation.After exhaust pipe heat insulation designed,aldehyde emissions did not change obviously at low engine load conditions (Tc ＜ 850 K),but aldehyde emissions decreased significantly at middle-high engine load conditions (Tc ≥ 850 K),and the decreasing range of unregulated emissions increased with exhaust temperature rising.It is conducive to the oxidation of unregulated emissions with prolonging the reaction time of unregulated emissions in high temperature environment after exhaust pipe heat insulation designed.Unregulated emissions decreased significantly with exhaust pipe heat insulation when the exhaust temperature (Tc) was higher than about 900 K.Exhaust temperature and reaction time had a greater influence on the oxidation of alcohol and aldehyde emissions.%通过对发动机排气管隔热保温,在JL368Q3型电喷汽油机上开展了醇类燃料发动机排气管保温降低醇醛排放的研究,采用气相色谱-氦离子化检测器(PDHID)快速检测方法检测发动机的醇醛排放.结果表明:与排气管保温前相比,排气管保温后醇排放降低,低负荷工况下(Tc ＜850 K)醛排放变化不大,中高负荷工况下(Tc≥850 K)醛排放降低,醇醛排放降幅随排气温度升高而变大.排气管保温延长了排气在高温下的反应时间,有利于未燃醇、醛的快速氧化,转速为4 000 r/min、负荷高于21 N·m时(Tc≥900 K),排气管保温后未燃醇、醛排放降低70％以上.排气温度和高温下的氧化反应时间对醇醛的氧化影响较大.