某船用柴油机匹配STC及EGR系统试验研究

Experimental Study on Matching STC and EGR System of a Marine Diesel Engine

针对传统船用增压柴油机低负荷时动力性较差及NOx排放较高问题,对某船用增压柴油机进行相继增压(STC)结合EGR系统改造,通过试验,研究推进特性负荷下,STC结合不同EGR率对柴油机动力性、经济性以及排放性能的影响。试验表明:在低负荷且0≤ηEGR≤0.06时,相比原机,Pk上升,Pz上升、gi下降、Soot值下降,同时,NOx值在STC的基础上显著降低;在高负荷且0≤ηEGR≤0.06时,可保证Pk、Pz、gi及Soot值与原机变化不大的基础上显著降低NOx值,弥补STC系统在高负荷时降NOx排放能力上的不足,如100%负荷、ηEGR=0.06时,相比原机,Pk降低4.32%,Pz降低1.45%,gi上升2.56%,Soot值增加0.037m-1,NOx值降低18.8%。

Aiming at the problem of poor power at low load and low NO x emissions in the traditional marine turbocharged diesel engine, the sequential supercharging (STC) combined with EGR system reform for a marine supercharged diesel engine.Through the test, the propulsion characteristic load is used, the STC combined with different EGR rates is applied to the diesel engine's influence of power, economy and emission performance, shows that :at low load and 0≤η EGR ≤0.06,compared with the original machine, Pk rises, Pz rises, gi decreases, Soot value decreases ,and NO x value decreases significantly on the basis of the STC .When the load is high and 0≤η EGR ≤0.06, Pk ,Pz, gi and Soot values can be significantly reduced on the basis of little change from the original machine, and significantly reduce the value of NO x, making up for the high pressure of the STC system that insufficient in reducing NO x emission capacity, for example,at 100% load and η EGR =0.06, compared with the original machine, Pk is reduced by 4.32%, Pz is decreased by 1.45%,gi is increased by 2.56%, and the Soot value is increased by 0.037m-1 the NO x value is reduced by 18.8%.