掺烧生物柴油耦合EGR对柴油机性能的影响及优化

Optimization of the Effect of Blending Biodiesel Coupled with EGR on Diesel Engine Performance

为探究掺烧生物柴油耦合废气再循环(EGR)技术对柴油机燃烧和排放性能的影响,基于TBD234V6型柴油机,运用AVL-fire软件建立仿真模型,对柴油机在75%中高负荷下运行时,0%、5%、10%和15%等4组不同EGR率与10%、20%、30%和40%等4组生物柴油掺混比进行仿真分析。仿真结果表明:在相同EGR率下,随着生物柴油掺混比增大,爆压、CO排放量和Soot排放量均呈下降趋势,NO排放量明显上升,当掺混比为40%时,柴油机各项性能值相比原机变化最为明显,爆压下降约16.3%,CO排放量下降约34.2%,Soot排放量下降约92.8%,NO排放量升高约35.7%;在相同掺混比下,随着EGR率的增大,爆压下降且滞后,NO排放量下降,当EGR率为15%时,相比掺混比为40%、EGR率为0的情况,爆压下降1.3%,NO排放量下降49.9%。通过增大喷油提前角对掺烧生物柴油耦合EGR技术进行优化,选取喷油提前角为29°CA、27°CA、25°CA、23°CA和21°CA进行研究。优化结果表明:增大喷油提前角有助于提升掺烧生物柴油耦合EGR技术的动力性,降低Soot和CO排放,当掺混比为40%、EGR率为15%时,喷油提前角由25°CA改为27°CA,其爆压上升3.8%,NO排放仍低于原机,整体排放依旧更优。

In order to explore the impact of blended biodiesel coupled with EGR technology on diesel engine combustion and emission performance,based on the TBD234V6 diesel engine,AVL-fire software is used to establish a simulation model,and the diesel engine is selected at 75%medium and high load operation,0%,5%,10%and 15%,which is a total of 4 groups of different EGR rates,10%,20%,30%and 40%,a total of 4 groups of different biodiesel blending ratios are simulated and analyzed.The results show that under the same EGR rate,as the biodiesel blending ratio increased,the explosion Pressure,CO emissions,and Soot emissions all show a downward trend,while NO emissions increase significantly.When the blending ratio is B40,the performance values of the diesel engine have the most significant changes compared to the original engine,the explosion pressure drop by about 16.3%,CO emissions decrease by about 34.2%,Soot emissions decrease by about 92.8%,NO emissions increase by about 35.7%.At the same mixing ratio,as the EGR rate increases,the explosion pressure decreases and lags behind,and the NO emissions decrease.When the EGR rate is 15%,compared to B40,the EGR rate is 0,the explosion pressure drops by 1.3%,and the NO emissions are lowered by 49.9%.After that,by increasing the fuel injection advance angle,the blended biodiesel coupled EGR technology is optimized,and the fuel injection advance angles of 29°CA,27°CA,25°CA,23°CA,21°CA are selected for research.The optimization results show that increasing the fuel injection advance angle helps to improve the dynamics of the biodiesel coupled EGR technology and reduce Soot and CO emissions.When the blending ratio is 40(B40)and the EGR rate is 15%,the fuel injection advance angle is changed from 25°CA to 27°CA,the burst pressure increases by 3.8%,the NO emission is still lower than the original machine,and the overall emission is still better.