高原缺氧环境下生物质燃料对柴油机性能和排放的影响

为了研究不同类别的含氧生物质燃料在高原缺氧环境下对发动机性能和排放的影响,在一台卧式双缸柴油机上分别燃用柴油、乙醇柴油E10(含10%体积分数的乙醇和90%体积分数的柴油)及生物柴油-乙醇-柴油B10E10(含10%体积分数的生物柴油,10%体积分数的乙醇和80%体积分数的柴油)3种燃料进行了对比试验。试验结果表明,在不对柴油机做任何调整的情况下,分别燃用E10和B10E10 2种含氧生物质混合燃料后,柴油机动力性下降,外特性转矩平均下降幅度分别达到4.24%和5.49%;当量燃油消耗率基本低于柴油,经济性有所改善。燃用含氧生物质燃料后,柴油机的经济性变化情况除了与燃料本身的属性相关,还与转速和负荷相关。燃用E10混合燃料后,柴油机的一氧化碳(CO)排放在低负荷时高于柴油,高负荷时低于柴油;碳氢化合物(HC)排放高于柴油水平,升高幅度范围达4.9%~27.4%;氮氧化物(NOX)排放在低负荷时低于柴油,高负荷时趋于柴油水平。燃用B10E10混合燃料后,一氧化碳(CO)和碳氢化合物(HC)排放在低负荷时都趋于柴油水平,高负荷时都低于柴油水平;氮氧化物(NOX)排放在低负荷时低于柴油,高负荷时高于柴油水平。柴油机在燃用E10和B10E10 2种混合燃料后,碳烟排放均低于柴油水平。柴油机燃用B10E10混合燃料后的碳氢化合物(HC)排放,碳烟排放以及低负荷时的一氧化碳(CO)排放均低于E10,氮氧化物(NOX)排放基本高于E10。与E10燃料相比,B10E10混合燃料在柴油机的一氧化碳(CO)和碳氢化合物(HC)以及碳烟排放方面具有更好的改善效果;但是动力性下降幅度较大,氮氧化物(NOX)排放增加。该研究可为含氧生物质燃料在高原缺氧地区的应用提供参考。

Effects of biofuels on performance and emissions of diesel engine under high-altitude hypoxic condition

Abstract: In order to study the influence of different categories of oxygenated biofuels on the performance and emissions of a diesel engine in a high-altitude anoxic condition, comparative experiments on a horizontal two cylinder diesel engine by use of three fuels: pure diesel, ethanol-diesel E10 (containing 10% ethanol in volume percentage and 90% petroleum diesel in the blend fuel), and biodiesel-ethanol-diesel B10E10 (containing 10% biodiesel, 10% ethanol, and 80% petroleum diesel) blends were carried out. In the process of the test, the engine was not adjusted or modified. The test results showed that when fueled with the E10 and B10E10 oxygenated blended biofuels respectively, the power performance of the diesel engine decreased, and the average drop of the engine brake torque at full-load are 4.24% and 5.49%. And the brake specific energy consumptions (BSEC) of the blended fuels were basically lower than those of the diesel fuel, and the fuel economy improved. The properties of the blended fuels had effects on the changes of the engine fuel economy, and the changes were also related to the engine speed and load. When fueled with the E10 blended fuel, the carbon monoxide (CO) emissions of the engine increased at low loads and decreased at high loads. The hydrocarbon (HC) emissions of the engine were higher than those of the diesel fuel and the percentage range of increment was 4.9%~27.4%. And the nitrogen oxide (NOX) emissions were lower than those of the diesel fuel at low loads, which tended to be the same level of the diesel fuel at high loads. When fueled with the B10E10 blends, the carbon monoxide (CO) emissions and the hydrocarbon (HC) emissions of the engine tended to be the pure diesel fuel level at low loads and decreased at high loads. And the nitrogen oxides (NOX) emissions decreased at low loads, and increased at high loads. The soot emissions of the engine with the E10 and B10E10 fuels both decreased. The hydrocarbon (HC) emissions, the soot emissions, and the carbon monoxide (CO) emissions at low loads of the diesel engine fueled with the B10E10 fuel were all lower than those of the E10 fuel, while the nitrogen oxide (NOX) emissions were basically higher than the E10 fuel level. Compared with the E10 fuel, the B10E10 blended fuel had a better effect on the improvement of the carbon monoxide (CO) emissions, the hydrocarbon (HC) emissions, and the soot emissions of the diesel engine. But the decline in the engine power performance was larger, and the nitrogen oxide (NOX) emissions increased. The study can provide a reference for the application of oxygenated biofuels in high-altitude anoxic regions.