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增压直喷柴油机燃用生物柴油调整特性研究
Study on the Performance of the Diesel Engine Fuelled with Diesel and Biodiesel with Different Injuction Timings
【作者】 袁居安;
【导师】 张春化;
【作者基本信息】 长安大学 , 载运工具运用工程, 2008, 硕士
【摘要】 生物柴油是一种代用燃料,它可以从植物油,餐饮废油或动物脂肪中制得。在生物柴油制造过程中,动植物油与低碳醇进行酯交换反应生成脂肪酸甲酯,即生物柴油,并伴生有副产物甘油。生物柴油与石化柴油具有相似的理化性质,可以应用于大多数柴油机上而不需要对发动机进行改动或只需进行少量的改动。由于生物柴油属于可再生性和环境友好性燃料,被认为是柴油的战略性替代燃料,受到国内外的广泛关注。为了掌握柴油机燃用生物柴油及其与石化柴油调合燃油的性能,优化燃用生物柴油的使用技术,本文在充分认识生物柴油制取及其理化性质的基础上,对生物柴油及其与石化柴油调合燃油的使用性能进行了实验研究,并通过调整发动机喷油正时,进一步改善发动机燃用生物柴油及其混合燃料时的动力性、经济性和排放特性。在生物柴油使用性能实验研究中,试验燃油为石化柴油、纯生物柴油及纯生物柴油以25%体积比与石化柴油调合成混合燃油,其中纯生物柴油为大豆脂肪酸甲酯。试验用发动机为索菲姆四缸增压直喷式柴油机,试验中对喷油正时进行调整,包括原机的喷油正时、喷油正时提前2 oCA和4oCA以及推迟2 oCA和4oCA。在试验过程中,全面测试柴油机在各喷油正时下分别以石化柴油、纯生物柴油、调合燃油为燃料时的动力性、燃料经济性和排放特性,并进行对比研究。试验结果表明,柴油机燃用纯生物柴油和调合燃油时,柴油机的动力性基本可以保持,燃油消耗率略有升高,但比能耗略有降低,NOx排放增多,但碳烟排放减少。随喷油正时提前,柴油机的经济性提高,NOx排放增多,碳烟排放减少,改变喷油正时使柴油机动力性普遍降低,只有在喷油正时提前2 oCA下,燃用混合燃油时动力性会有提高。
【Abstract】 Biodiesel is one kind of alternative fuel, which can be manufactured from vegetable oils, recycled cooking greases or oils, or animal fats. In the process of biodiesel manufacturing, vegetable oil and animal fats are converted into fatty acid methyl esters or FAME, the major content of the biodiesel, and the Glycerine as by-product. It has the similar characteristics with diesel and can be used as alternative fuel on diesel engine with no or only minor modifications. Biodiesel gradually attracts people’s attention and is seen as the strategic alternative fuel for diesel because of its renewable character and friendly character to environment.For deeply understanding diesel engine performance when fueled with biodiesel and the blend of biodiesel/diesel and optimizing the applying technology of biodiesel on diesel engine, the study on diesel engine fueled with biodiesel was conducted. Based on deeply understanding to biodiesel produce process and its physical and chemical characteristics, the paper studied the using performance of biodiesel and the blend of biodiesel/diesel. Futhermore, injection timing is adjusted for finding a way to improve diesel engine’s performance and emission when fuelled with biodiesel and blend.Fuels used in the experimnet are Petroleum Diesel, biodiesel and the blend of 25% biodiesel and 75% Petroleum Diesel in volume ratio. the biodiesel used in the experiment is soybean fatty acid-first ester. the engine used in the experiment is a Sofim four-cylinder turbo charged direct injection diesel engine. Injection timing is changed into five different injection timings ,which include : original injection timing, advanced injection timing in 2 oCA and 4oCA, retarded injection timing in 2 oCA and 4oCA.the result shows that engine power could be remained or even higher, the fuel consumption slightly increased, but the specific energy consumption decreased slightly, though NOx emission level gets to be higher, the particulate matter(PM) emssion is decreased when the engine fuelled with biodiesel or blend. With injection timing starts to take place earlier the fuel consumption becomes less, NOx emission level is higher and PM emission level is lower. Adjusting the injection timing leads to general decrease of the engine power, but only the power could increase when fuelled with blend and the injection timing is 2 oCA advance.
【Key words】 diesel engine; biodiesel; injection timing adjustment; optimization;