Simulation analysis of the effects of methanol-polyoxymethylene dimethyl ethers blends on combustion and emissions of a PCCI engine

¹ School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013, China
² Science Research Institute, Weichai Power Co., Ltd, Weifang 261061, China

^* Corresponding author’s e-mail: jq@ujs.edu.cn

Abstract

The effects of methanol/polyoxymethylene dimethyl ethers (PODE) mixture with different blending ratios on premixed charge compression ignition (PCCI) combustion and emission performance have been researched through the anlysis of CFD software CONVERGE. Premixed combustion is achieved by a single early injection of fuel into the cylinder. The results show that the combustion start point delays and the peak pressure decreases with the increase of methanol blend ratio. The effects of injection timing on the combustion and emission characteristics of PCCI were studied by using a mixture of the same proportion of methanol. The results show that the advance of injection time leads to more homogeneous mixture and higher peak heat release. But too early injection reduces the temperature in the cylinder and makes the combustion worse, resulting in the increase of HC, soot and CO emissions. NO_x emissions decrease with the advance of the injection time.