An Experiment Study On Fuel Spray On Heavy-duty Diesel Engine

With the shortage of energy and the increasing demand for power,economy,and emission characteristics of automobiles,scholars have also paid more and more attention to the research of fuel atomization for vehicle engines,because the quality of fuel atomization is one of the most important factors determining the combustion process.However the theoretical research on fuel atomization is still far from mature.In recent years,new emission regulations have been introduced to reduce the emission of particulate and nitrogen oxides from diesel engines.High pressure fuel injection has become the development of technology,and the research of fuel atomization has become the focus of research in the field of engine.Therefore,it is of great engineering value and academic significance to carry out the research on the electronically controlled high pressure fuel injection system of diesel engine and its fuel atomization characteristics.In this paper,a model of heavy-duty diesel fuel injection system is taken as the research object and spray constant volume vessel,environmental temperature and pressure control device,image acquisition system and synchronous trigger system were designed.The structure of the spray constant volume vessel was completely symmetrical.Its quartz glass component was the most vulnerable parts,so the strength of the quartz glass component was checked and its size was optimized.Height and wall temperature regulating platform for fuel impingement was developed,and the effect of injection pressure,environmental pressure,wall distance,wall temperature and roughness could be studied with the platform.The envirornment pressure and temperature control device were developed,which can adjust the temperature and pressure.The hardware and software modules of the synchronous trigger system of the injector and high speed photogrammeter were developed and a visual spray test platform for electronic control high pressure fuel injection system was set up.In this paper,sample standard deviation was selected as an evaluation index for evaluating the spray uniformity of a porous injector and penetration distance,cone angle and projection area were selected as evaluation indexes for evaluating the atomization quality of the single hole injector and spreading radius and reel height were selected evaluation index for evaluating spray atomization quality of impinging wall spray.With MATLAB software,different image processing software was developed for different evaluation parameters.The free jet spray test of a porous injector and a single hole injector was carried out in this paper.The spray uniformity of the porous injector was studied under different injection pressure and ambient pressure.The spray characteristics of the single hole injector under different injection pressure,ambient pressure,hole diameter and ambient temperature were studied.The influence of the injection pressure,the environmental pressure and the diameter of the jet hole was compared by the differential analysis.It was proved that the main factor that affected the penetration distance and the area of the oil beam was the diameter of the jet hole,and the influence on the cone angle of the oil beam was the environmental pressure.In this paper,the influence of injection pressure,ambient pressure,impinging distance,wall temperature and wall roughness on the spray characteristics of impinging wall was analyzed.The influence of the influence factors on the spray characteristic parameters was compared by the influence index.