预喷正时对甲醇-柴油双燃料发动机超细颗粒物和NO_(x)排放的影响  

Effects of diesel pre-injection timing of methanol-diesel dual-fuel engines on ultrafine particulate matters and NO_(x)

作　　者：李阳阳[1,2] 陈欢 程志腾[1] LI Yang-yang;CHEN Huan;CHENG Zhi-teng(School of Automobile,Chang’an University,Xi'an 710064,China;Key Laboratory of Shaanxi Province for Development and Application of New Transportation Energy,Xi'an 710064,China)

机构地区：[1]长安大学汽车学院,西安710064 [2]陕西省交通新能源开发应用与汽车节能重点实验室,西安710064

出　　处：《安全与环境学报》2021年第5期2309-2318,共10页Journal of Safety and Environment

基　　金：陕西省重点研发计划项目(2018ZDCXL-GY-05-06,2019ZDLGY15-07);中央高校科研业务费项目(300102220112)。

摘　　要：为探究预喷正时对甲醇-柴油双燃料发动机超细颗粒物和NOx排放的影响,通过优化甲醇-柴油双燃料技术,以减少污染物排放。将一台电控共轨柴油机改造的双燃料发动机作为试验对象,在1800 r/min,30%、70%负荷,10%~40%掺烧比下,调整预喷正时,以对放热率、缸内平均温度、数浓度、平均粒径等指标进行计算和归纳。结果表明:相比单次喷射,预喷射可明显改变燃烧过程,放热过程更平缓;大负荷掺烧比30%~40%时,预喷引起放热双峰更明显;随预喷正时提前,预喷引发的第一阶段放热越来越少;预喷柴油策略可提高缸内温度。除小负荷掺烧比30%~40%工况,预喷射可使超细颗粒物数量增多、平均粒径增大,且提前预喷正时可降低50%颗粒物数量。预喷射会提高NOx排放,但提前预喷正时可降低NOx排放,除小负荷10%~30%掺烧比,NOx排放均高于单次喷射。The paper aims to explore the effects of diesel pre-injection timing of methanol-diesel dual-fuel engines on ultrafine particulate matters and NOx,optimizingmethanol-diesel dual-fuel technology and reducing the emissions.In this paper,the test methanol-diesel dual-fuel combustion was modified from an electronically controlled common rail 4-cylinder engine.At 1800 r/min,30%and 70%load rates,10%-40%co-combustion rates conditions,we adjusted the pilot diesel injection timing and tested the cylinder pressure signals,ultrafine particles,and NOx emissions.The heat release rate and average temperature in-cylinder were calculated using a zero dimension model based on cylinder pressure signals.The particle-size spectra,total number concentration,and mean diameter were calculated using the ultrafine particles and NO emissions data.It can be revealed that the diesel pre-injection significantly changes the combustion process of the test methanol diesel dual fuel engine.Compared to the single injection mode,the ignition delay period caused by the diesel main injection is much shorter,and the heat release process of the double injection mode is smoother.The two peaks in the heat release rate curve aremore obvious with the pre-injection strategy at 30%-40%co-combustion rates at high load conditions.The released heat caused by the pre-injection at the first combustion process decreases with the advance of pre-injection timing.The average temperature in the cylinder increases with the application of diesel pre-injection.At 30%load,with the advance of pre-injection timing,the temperature in the cylinder decreases.However,at 70%load,with the advance of pre-injection timing,the temperature in the cylinder first increases then decreases.The ultrafine particle numbers and mean diameters increase with the application of diesel pre-injection,except 30%-40%co-combustion rates at low load conditions.The advance of diesel pre-injection timing could decrease the ultrafine particle numbers(e.g.,it decreases by 50%at 30%-40%co-combustion rate

关 键 词：环境工程学 甲醇-柴油双燃料 预喷正时 超细颗粒物 NO_(x) 

分 类 号：X511[环境科学与工程—环境工程]