Research On Ignition Characteristics Of Gasoline Droplet On The Hot Surface Of Automotive Three-way Catalytic Converter

The ignition mechanism of oil on hot surface is very complicated,which is affected by many factors such as hot surface material,surface roughness,oil properties,and surface temperature.In this paper,under the conditions of controlling oil properties,hot surface materials,ambient temperature and humidity,a self-designed and built ternary catalytic converter hot surface oil experimental bench is used to simulate a car driving for a long time or the exhaust system fails.The heat generation of the three-way catalytic converter and surrounding devices,combined with high-speed photography technology and the in-house Matlab image processing program,explore the ignition characteristics of gasoline droplet on the three-way catalytic thermal surface.The main conclusions drawn by the paper include:Under the experimental conditions of this paper,the minimum temperature at which 92#gasoline can be ignited on the hot surface is 604.6?.With the increase of oil quantity,the ignition probability of gasoline on the hot surface increases significantly;in a single oil drop experiment,the minimum temperature at which 10?l of gasoline can be ignited is 609.8?,and the minimum temperature at which 6?l of gasoline can be ignited is 637.8?,and the minimum temperature required for other oil to be ignited by a hot surface is somewhere in between.In the three cumulative oil drop experiment,the ignition probability of the 6?l and 8?l oil drop is large for the third time,and the first ignition probability is large when the oil amount is above 8?l;the way of dripping oil has little effect on the ignition law of gasoline hot surface;92#gasoline dripping on the hot surface can be divided into four levels of danger.Three-stage flame structure of hot surface ignition gasoline is obtained,which is divided into blue flame structure,blue flame-hot flame double structure and hot flame structure;summarize the characteristic flame parameter range of blue flame and hot flame at various oil amounts and temperatures,in which the temperature of blue flame is 200?500? and the temperature of hot flame is 600?1350?;the larger amount of oil and the more times the oil is dropped,the sooner the flame height reaches a dangerous value of 8 cm.The spread speed of blue flame can be as high as 6.85m/s,which is larger than that of hot flame.The lateral flame propagation speed is faster than the longitudinal direction.The maximum lateral propagation speed of the blue flame is 1.03?2.04 times of the longitudinal direction,and the lateral propagation speed of the yellow flame is 1.36?7.04 times of the longitudinal direction.According to the minimum temperature,probability and flame temperature hazard analysis required to ignite 92#gasoline on a hot surface,it is concluded that more than 10?l of gasoline dripping on a high temperature hot surface and burning will cause a great risk of automobile fire.