EGR技术对生物柴油混合燃料发动机性能的影响研究

Research on the effect of EGR technology on the performance of biodiesel hybrid engine

为缓解柴油掺烧生物柴油导致的NO_(x)排放过高问题,将4190ZLC船用中速柴油机作为试验台架,通过AVL_FIRE软件建立燃烧室模型,并验证该模型准确性。设置生物柴油掺混比0~40%等4组变量,EGR率0~12.5%等4组变量,进行柴油机燃烧、性能和排放分析。结果表明,掺烧适量生物柴油能够降低柴油机缸内温度,降低Soot排放,但同时会导致NO_(x)排放明显升高;EGR的引入能够实现低温燃烧,显著降低NO_(x)排放,但EGR率过高会增加Soot排放。生物柴油掺混比B40、EGR率12.5%组合NO排放比原机降低47.7%,Soot排放质量分数比原机降低98.13%。本文结果将为柴油掺混生物柴油燃烧并结合EGR技术提供一定的研究方向。

In order to alleviate the problem of high NO_(x)emissions caused by diesel mixed with biodiesel,a dual-fuel combustion chamber model was constructed by AVL_FIRE software on the basis of the 4190ZLC marine medium-speed diesel engine bench,and the accuracy of the model was verified.Four sets of variables of biodiesel mixing ratio 0~40%and EGR rate of 0~12.5%were set to analyze diesel engine combustion,performance and emissions.The results show that the mixing of an appropriate amount of biodiesel can reduce the temperature in the diesel engine cylinder and reduce the Soot emission,but at the same time,it will lead to a significant increase in NO_(x)emission.The introduction of EGR enables low-temperature combustion and significantly reduces NO_(x)emissions,but too high an EGR rate increases Soot emissions.The biodiesel blending ratio of B40 and EGR rate was 12.5%,the combined NO emission was reduced by 47.7%compared with the original unit,and the mass fraction of Soot emission was 98.13%lower than that of the original machine.The research results can provide a certain guiding basis for the low-temperature combustion of diesel/biodiesel/EGR in marine diesel engines.