| Characterised by “homogenization premixing,low temperature combustion”,internal combustion engine as a new ignition way,it is not only combined with the advantages of gasoline engine and diesel engine,but it can also reduce the emission of NOx and PM.In order to resolve the difficulty of ignition phase controlling,the research group has put forward the jet-flow flame igniting diesel oil premix mixture,which is called the jet controlled compression ignition(JCCI).The paper mainly probes into how different pre-chamber structure parameters(such as volume,orifice diameter d,length diameter ratio L/D.)affects jet-flow flame and premixed mixture ignition process.This research is experiment research,and it is finished on self-designed and self-established constant volume combustion bomb visual experimental platform.Matched with Schlieren and high-speed camera,the process of jet-flow flame spurt from the chamber and jet-flow flame igniting methane air premixed mixture can be photographed.The following conclusions are drawn in the study of the characteristics of jet flame characteristics.By comparing the pre-chamber of 1.9 m L and 1.0 mL,the length of 1.9m L pre-chamber L is long.The time that flame spread from the spark plug to pre-chamber orifice is long,which leads to jet time is late.The amount of the mixture of the gas in the 1.9ml pre-chamber is large,and the resulting pressure is high,leading to the penetration of the jet flame and the area of the flame are large.We make a conclusion by comparing the 1 mm,2 mm and 3 mm aperture pre-chamber,after 1 mm aperture pre-chamber between indoor and constant volume incendiary throttling effect is stronger.pre-chamber indoor mixture is on fire,inside short time pre-chamber indoor pressure rise even higher,causing jet flame jet ahead of time,and through the distance and flame area is larger.When the temperature of the pre-mixture is low,the 1mm aperture pre-chamber will cause the jet flame to quench,which will not ignite the pre-mixing gas in the combustion chamber.By comparing pre-chamber with the length of diameter ratio of 1.0 and 2.0,The time of length to diameter ratio of 1.0 pre-chamber indoor mixture in the combustion reaction is shorter,which causes the length to diameter ratio of 1.0 pre-chamber indoor mixture combustion that is insufficient.The following conclusions are drawn from the research on the characteristics of pre-mixed gas combustion.Inside the jet flame will produce ignition area,ignition area at the center of the constant volume vessel.Compared with the spark plug direct ignition,the flame propagation path reduced significantly.Because the effect of turbulence of the jet flame can be more to speed up the spread of flame.The pressure peak and the pressure rise rate of the pre-mixture is significantly greater than spark plug direct ignition.By comparing pre-chamber with different volume(1.0 m L and 1.9 m L)and different diameter(2 mm,3 mm).The jet time of jet flame will affect the mixture of ignition point.The pressure peak and pressure rising rate of 1.9 m L pre-chamber and 2 mm aperture pre-chamber ignition of the mixture obviously is very high at 400 k,which make the internal pre-mixture fully burning and burning rate is fast.By comparing the pre-chamber with the length to diameter ratio of 1.0 and 2.0,when fuel to air ratio is 1.0,the reaction time of length to diameter ratio of 1.0 pre-chamber indoor combustion is shorter.Inadequate burning can lead to adverse factors.The spread speed become slowly in later the mixture of flame.The peak pressure curve is low.The time of the mixture on fire becomes later. |
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