中介尺度内燃机甲醇-汽油混合燃料燃烧可视化研究OA北大核心

Based on the Tuoyang FS-S100AT four-stroke piston micro gasoline engine,an intermediate scale visual combustion test platform for micro internal combustion engines was established to investigate the effects of various methanol-gasoline mass fractions(M100,M75,M50,M25,M0)and excess air coefficients(λ=1.2,1.0,0.8)at a test speed of 10 000 r/min on the flame front.It was indicated that all the evaluated fuel samples exhibited a light blue flame during the preliminary phase of combustion.As the depth of combustion intensified,fuels with elevated methanol contents(M100,M75,M50)exhibited a faint yellow flame or intense yellow particulate emissions at the piston's periphery.Conversely,fuels with reduced methanol contents(M25,M0)experienced delayed flame propagation due to the constraints of gasoline's combustion velocity,resulting in cooler cylinder temperatures.Consequently,the flame predominantly maintained a light blue hue,with an occasional appearance of a yellowish flame or particulate matter.Generally,as the methanol blending ratio diminished,the rate of flame propagation correspondingly decreased.Nevertheless,within a specific range,an augmentation in the concentration of the mixture led to an elevated flame propagation velocity.When λ was 1.0,the yellow flame region within the combustion flame attained its peak.M100 fuel,in particular,experienced the most rapid escalation in yellow flame area,yet the rate of expansion tapered off as the methanol blending ratio diminishes.The augmentation of the yellow flame area is correlated with the inadequate oxidation of the lubricating oil,as well as the distinctive structures of the intake and exhaust valves within the internal combustion engine.