高压缩比甲醇发动机的排放仿真研究

Emission Simulation of High Compression Ratio Methanol Engine

为了满足未来更为严格的排放法规要求,以某款传统柴油发动机为例,采用一维GT-Power和三维CFD仿真软件搭建火花点火式甲醇发动机的一维、三维物理模型,通过调整点火时刻,分析不同的当量比和EGR率对发动机排放的影响。研究结果表明:随着点火时刻的推迟,CO排放先减少后增加,NO_(x)排放和CO_(2)排放都减少,未燃甲醇和甲醛排放近乎于0,其中点火角为-10°ATDC时,排放性较好;点火角为-10°ATDC时,随着当量比增大,CO排放增加,NO_(x)排放减少,CO_(2)排放则先增加后减少,未燃甲醇和甲醛排放近乎于0;点火角为-10°ATDC时,随着EGR率增大,CO排放增大,NO_(x)和CO_(2)的排放都减少,未燃甲醇和甲醛排放近乎于0。

In order to meet the requirements of stricter emission regulations in the future,one-dimensional GT-Power and three-dimensional CFD simulation softwares were used to build the one-dimensional and three-dimensional physical models of spark ignition methanol engine by taking a traditional diesel engine as an example.By adjusting the ignition timing,the effects of different equivalent ratios and EGR rates on engine emissions were analyzed.The results show that CO emission decreases first and then increases,NO_(x) and CO_(2) emissions both decrease,and the emissions of unburned methanol and formaldehyde are almost close to 0 with the delay of ignition timing.When the ignition angle is-10°ATDC,the emission is better.With the increase of equivalent ratio or EGR rate,CO emissions increase,NO_(x) emissions reduce,and the emissions of unburned methanol and formaldehyde are almost close to 0.CO_(2) emission reduces in the end,but first increases with the increase of equivalent ratio.