Visualization Study On Combustion Characteristics Of Methanol By Ignition Chamber Jet-ignited

Further improvement and optimization of the combustion mode of internal combustion engines and the search for cleaner alternative fuels are effective means to achieve energy saving and emission reduction of internal combustion engines.Methanol has many advantages as an alternative fuel,and the jet ignition method of the ignition chamber can achieve rapid combustion.In this paper,under the guidance of JCCI(JCCI,Jet Controlled Compression Ignition)ideas,a visual study is made on the ignition and combustion process of ignition chamber jet igniting methanol.In this paper,a visual experiment is carried out on a constant volume chamber experimental platform.The shadow method is used to study the ignition and combustion processes of methanol premixes ignited in different ways and different ignition chamber parameters.The experiment first analyzed the main ignition period and combustion efficiency of the three ignition methods,follow-up experiment mainly analyzes the injection time of the jet medium in the ignition chamber,the moment the jet medium ignites the methanol premix in the main combustion chamber,the pressure curve of the ignition chamber and the main combustion chamber,the pressure rise rate curve of the main combustion chamber and the heat release curve.In this paper,the effects of ordinary spark plugs,high-energy spark plugs and ignition chamber jet ignition systems on the combustion effect of methanol premix in the main combustion chamber are mainly compared and studied.The experimental results show that the jet ignition system of the ignition chamber can not only ignite more methanol premix,increase the combustion efficiency by about 7%,but also shorten the main combustion period by about 72%.Therefore,in this paper,the effects of ignition chamber volume,injection hole diameter and injection hole number and other ignition chamber geometric parameters on the ignition chamber jet ignition methanol system were studied.At the same time,the article also studied the influence of the ignition chamber methanol premixed gas equivalent ratio and other mixture parameters on the ignition system of jet ignition methanol.The experimental research in this paper shows that increasing the volume of the ignition chamber can provide greater ignition energy,but a certain ignition delay will occur.And it is better to select a larger volume of the ignition chamber to ignite the ignition delay within an acceptable range.If the diameter of the injection hole of the ignition chamber is too small,it will cause the phenomenon that the jet medium is difficult to eject,thereby causing a major delay at the main moment.In this paper,the main combustion period of the single-hole 2mm ignition chamber is shortened by about 28% compared to the single-hole 3mm ignition chamber,but the combustion efficiency of the methanol premix in the main combustion chamber will be reduced by about 7%.The crosssectional area of the orifice of the double-hole 2.12 mm ignition chamber and the single-hole 3mm ignition chamber is fixed.Adding an orifice can advance the jet medium injection time and the ignition timing of the methanol premix in the main combustion chamber,but it will cause the main combustion period is extended by about 24%,and the combustion efficiency is reduced by about 5%.The dual-hole 2.12 mm ignition chamber has the same diameter as the single-hole 2mm ignition chamber.Adding an additional orifice will delay the jetting time of the jet medium and the main combustion period will be extended by about 64%,but the combustion efficiency can be increased by about 2%.The equivalent ratio of methanol premixed gas in the ignition chamber is between 1.1 and 1.3.There is an optimal equivalence ratio,which can realize the jet medium ejected from the nozzle and quickly ignite the methanol premixed gas in the main combustion chamber.The ratio is 1.2.Based on the above,this paper also conducted a certain research on the lean combustion limit that 6mL,2mm ignition chamber can expand.This study found that the 6mL,2mm ignition chamber can still quickly ignite the methanol premix in the main combustion chamber when the equivalent ratio of the main combustion chamber is 0.55.