Research On The Effect Of Injection Strategy On The Combustion Mode Of Reactivity Control Compression Ignition

In the research of many combustion technologies,the Reactive Control Compression Ignition mode has attracted extensive attention of internal combustion engine researchers due to its high degree of controllability of combustion phase.In order to better understand the in-cylinder combustion process in the RCCI combustion mode,it is necessary to explore the influence of the injection strategy on the combustion performance and analyze the combustion mechanism.Therefore,based on the test bench and simulation platform of the RCCI combustion mode,this paper analyzes the influence of the injection strategy on the combustion performance of the RCCI engine in the methanol-diesel dual fuel mode.The main research contents are as follows:Based on the methanol-diesel dual-fuel test platform modified in the laboratory,this paper firstly studies the change of methanol substitution rate（30%,40%,50%,60%）,the first injection time of diesel,and the At the time of secondary injection,the injection pressure and excess air coefficient of diesel direct injection,the influence of different parameters on combustion was analyzed.The research results show that: the increase of methanol substitution rate will lead to the increase of ignition delay period and the shortening of combustion duration;the advance of the first injection time of diesel will lead to the lag of the combustion center of gravity,and the influence will increase with the increase of methanol substitution rate;the secondary injection time of diesel The advance will lead to the rise of the cylinder pressure peak and the change of the heat release pattern.The increase of the injection pressure of diesel direct injection will lead to the concentration of heat release and the decrease of the excess air coefficient will lead to the delay of the heat release.In order to further study the methanol substitution rate,which has the greatest influence on the fuel activity control in the methanol-diesel compression ignition mode,n-heptane was selected as the substitute fuel for diesel,and the detailed in-cylinder combustion process of methanol/n-heptane with different methanol substitution rates was carried out.Simulation analysis.Set the spray model,turbulence model,and combustion model through CONVERGE,select the appropriate reaction mechanism for simulation calculation,observe the change of the temperature field in the cylinder through Tecplot 3D software,conduct dynamic analysis from the perspective of chemical reaction kinetics,and study the effect of methanol substitution rate on RCCI The combustion process further improves people’s understanding of the combustion process of methanol-diesel RCCI.