Experimental Study Of Dual-fuel Combustion Mode On Compression Ignition Engine Fueled With Biogas/Diesel

Nowadays,in consideration of energy shortage and environmental pollution issue around the world,experts in the field of internal combustion engine have been committed to finding and using renewable energy,improving the engine’s combustion mode,to achieve efficient and clean in-cylinder combustion.As renewable energy,biomass is getting widely attention because of its wide range of raw materials and the growing maturity of preparation process.Specially,biogas fuel has the advantage of low pollution and high efficiency,also has been widely used,and new combustion mode has been studied in recent years,so a dual-fuel combustion mode fueled with biogas and diesel is studied in a modified diesel engine in this paper.Firstly,this paper studies the influence of biogas substitution rate and load on engine emissions and thermal efficiency.The experimental results indicate that because of the large proportion of non combustion gas-N₂,the in-cylinder combustion temperature and air input quantity can be greatly influenced,so it is not suitable for the injection of high proportion biogas at low load;with an increase in the premixed ratio of biogas,the soot emission can be effectively suppressed.The high hydrogen content in biogas is helpful to increase the burning rate,reduce CO and HC emissions,and improve the engine thermal efficiency.When the low level of premixed ratio of biogas,the phenomenon of early burning appears at high load,which can reduce engine thermal efficiency and increase NOx emission.At high load,with an increase in EGR,the ignition delay,therefore,the optimization of combustion phase can be achieved by EGR,which can effectively inhibit the occurrence of early burn,and reduce NOx emission;through the analysis of the cyclic variation,the stability of in-cylinder combustion is not too large even at the high EGR level.Further adjusting the injection parameters of DI diesel,this paper founds that by changing the main injection timing and the pre-injection ratio,the combustion phase can be effectively controlled and emissions can be improved,which can achieve the optimization of biogas/diesel dual-fuel combustion mode.