甲醇/柴油双燃料发动机超低排放集成控制试验研究

Experimental Study on Ultra-low Emissions Integrated Control of Diesel/Methanol Dual-fuel Engine

在一台非道路共轨柴油机上增设一套甲醇喷射系统,实现了甲醇/柴油双燃料燃烧模式,在非道路国Ⅳ排放法规稳态八工况(NRSC)测试条件下,利用尾气分析仪和FTIR对比研究了纯柴油模式和双燃料模式的排放特性,并系统分析了DOC+DPF+SCR后处理系统对双燃料发动机尾气排放的转化效率。试验结果表明:甲醇/柴油双燃料燃烧模式的NO_(x)和Soot排放明显低于纯柴油模式,而CO、HC、甲醇和甲醛排放却高于纯柴油模式;经过后处理系统后,对CO和HC排放的转化效率高于99%,同时NO_(x)和Soot的平均降幅分别为84%和90%,而双燃料模式的甲醇和甲醛排放能够被高效氧化,平均净化效率在90%以上。NRSC测试结果表明双燃料发动机加装DOC+DPF+SCR后CO、HC、NO_(x)和PM比排放指标均低于非道路国Ⅳ和欧Ⅴ排放法规限值。

A methanol injection system is installed on a non-road common-rail diesel engine to realize the methanol/diesel dual-fuel combustion mode.Based on the non-road China-Ⅳ regulation Non-Road Steady Cycle(NRSC) test conditions,the emission characteristics of pure diesel mode and dual-fuel mode were comparative studied by using exhaust gas analyzer and FTIR.And the conversion efficiency of DOC+DPF+SCR post-treatment system on the dual-fuel engine exhaust emissions was systematically analyzed.The results show that the NO_(x) and Soot emissions of methanol/diesel dual-fuel combustion mode are significantly lower than those of pure diesel mode,while the CO,HC,methanol and formaldehyde emissions are higher than those of pure diesel mode.After the post-treatment system,the conversion efficiency of CO and HC emissions is higher than 99%.Meanwhile,the conversion efficiency of NO_(x) and Soot emissions is 84% and 90%,respectively.The methanol and formaldehyde emissions of dual-fuel mode can be oxidized efficiently,and the average efficiency is more than 90%.NRSC test results show that the CO,HC,NO_(x) and PM specific emission indexes of dual-fuel engine equipped with DOC+DPF+SCR are lower than the limits of non-road China-Ⅳ and Euro-V regulations.