Influence Of Premixed Ignition Parameters On Combustion Cycle Variation Of Natural Gas Engine

With the increasingly prominent problem of oil supply contradiction in China in recent years,coupled with the increasingly strict laws and regulations related to automobile emissions,natural gas has gradually become the main fuel to replace the power machinery,which can effectively solve the problem that the traditional power machinery relies too much on traditional fuel fuels.However,due to the excessively slow combustion rate of natural gas,it is very easy to have the problem of combustion cycle change,and the application of lean burning technology leads to the aggravation of combustion cycle change.Therefore,through simulation experiments,this paper explored the premixed ignition parameters in the cylinder of natural gas engine,and carried out research on the influence of combustion cycle variation.Taking 12V190 natural gas engine as the experimental bench research object,combined with the engine data acquisition system proposed by LabVIEW as the development platform,the high-speed acquisition card was used to collect premix point parameters in the cylinder to study the specific influence of ignition parameters on combustion cycle changes.In this study,by using a new type of venturi-mixer,the indicator diagram under a certain working condition can be obtained as a random continuous variable distribution,and the distribution function can be fitted by solving the maximum burst pressure and the probability density optimization of the corresponding crankshaft Angle,and the optimal fitting distribution curve can be drawn.It can be found that the optimal fitting distribution function of the maximum burst pressure is the gamma right-skewed shape distribution.Maximum explosion pressure value maximum probability,the corresponding crank Angle optimization fitting distribution normally distributed,with the mean as the numerical concentration area,and produce the probability density function curve of the maximum explosion pressure steeper,reflect the size of the crank Angle of existence value,the maximum explosion pressure fluctuates significantly smaller.In this paper,the FIRE software is used to change the core location and the size of the breakdown core.By studying the influence of combustion cycle changes caused by premixed ignition parameters in the cylinder,the research conclusions are as follows:(1)Through the optimization design of this paper,the starting difficulty of natural gas engine was found to be the main cause of the problem through data analysis:due to the excessive air coefficient in the starting state,the mixture concentration could not be adjusted in time,which eventually led to the problem of misfire.Therefore,this paper optimized the design of the mixer,through the addition of one-way valve,regulating valve,through MATLAB/SIMULINK to determine the optimal model size,through the experimental confirmation of the proposed design optimization scheme,for the natural gas engine starting difficulties to effectively solve the problem,to ensure that the later stage of bench test smoothly carried out.(2)Breakdown fire nuclear radius and(2)the center position,will produce the most significant influence the maximum explosion pressure,and the breakdown of fire nuclear radius size determines the nuclear fire location and axis deviation degree,the two were positively correlated,that is,the greater the breakdown of the nuclear radius of fire can lead to fire nuclear location and axis deviation,thus caused the maximum explosion pressure,and at the same time,the smaller the corresponding crank Angle;(3)Through the simulation study in this paper,the optimized fitting regression equation between the radius,position of the core of fire and the maximum explosion pressure can be established,and the optimized fitting regression equation among the maximum explosion pressure,radius of the core of fire and the deviation from the axial position of the core of fire can be obtained through the orthogonal simulation experiment.Through the test,the size of the radius of the core and the result range of the core's position deviating from the axis are determined,and it is found that the cycle of combustion has started at the ignition breakdown stage,until the end of the final combustion,so it is confirmed that the premixed ignition parameters in the cylinder are one of the main influencing factors to cause the cycle of combustion.