Analysis Of Combustion Process Of Wall-guided Two-stroke LPG Direct Injection Turbocharged Engine

With the rapid development of science and technology and the continuous progress of human society,the number of vehicles worldwide has also increased year by year.In response to the country's call for energy-saving and emission reduction,this paper further studied the combustion technology in the cylinder.The AVL fire software was used to numerically analyze the combustion process of the wall-guided two-stroke LPG direct injection turbocharged engine.This paper first introduces the specific arrange structure and working principle of the wall-guided combustion system,and builds the grid model of the combustion system accordingly.Secondly,in order to shorten the calculation time and improve the work efficiency,the mechanism of LPG chemistry was simplified using CHEMKIN,simplifying the detailed mechanism model containing 155 components and 689equations into a simplified mechanism consisting of 32 components and 69 equations.The model verifies the effectiveness of the simplified mechanism model and couples it into the Fire.At the same time,in order to make the research results more precise,this paper verifies the feasibility of free spray,in-cylinder gas mixture and combustion model.Comparing with the experimental outcomes,the calculated outcomes are persistent substantially,indicating that the calculation method and the calculation model are feasible.After completing the above-mentioned preliminary work,this article describes the formation process and partial load conditions of the homogeneous mixture under heavy load conditions?4800 rpm,80%load?,cold start-warm conditions?2000 rpm,20%load?.?4800 rpm,50%load?The formation of the lower stratified gas mixture was numerically analyzed.The results showed that under heavy load conditions?4800rpm,80%load?under 45°CA ABDC injection,cold start-up conditions?2000 rpm,20%load?,50°CA ABDC injection,part load conditions?4800 rpm,50%load?Under the 55°CA BTDC injection,the homogeneous mixture formed in the cylinder at the end of the compression stroke is optimal.Based on the formation of the ideal mixture in the early stage,this article also carried out the combustion and discharge of the mixture in the cylinder under partial load conditions?4800 rpm,50%load?and cold start-warm conditions?2000 rpm,20%load?.Numerical analysis.The results show that the 20°CA BTDC ignition under cold start-warm conditions?2000 rpm,20%load?has the highest peak heat release rate and the best combustion characteristics of the engine;under partial load conditions?4800 rpm,50%load?,25°CA BTDC ignition,the maximum peak heat release rate,the best combustion characteristics;by comparing the combustion conditions of the mixture under different conditions,we can see that the average pressure and heat release rate of the engine cylinder in the same general trend,but due to the impact of factors such as fuel injection The average pressure and the rate of heat release are different.The average pressure and heat release rate in homogeneous combustion are significantly greater than those in stratified combustion.The moment of ignition has a certain impact on the emission of CO,CO₂,and NO.Properly postponing the ignition timing within a certain range is beneficial to reducing CO,CO₂,and NO emissions.