Study On The Diesel Spray Characteristics At Variable Injection Conditions With Invariable Oil Quantity

Nowadays,automotive engine’s better performance in its fuel economy,dynamic and emissions is required by today’s society.Ideal characteristic of spray can cause a great burning and improve engine’s dynamic,economy and emission performance.Therefore it’s particularly important to grasp how diesel engine’s spray and burning process is influenced by different environment conditions and injection conditions.By using EFS equipment to test the oil mass of single-hole electromagnetic injector nozzles(three different diameters-0.18 mm,0.22 mm,0.26mm),whose injection pressure ranges from 40 MPa to 160 MPa.As a conclusion,both improved injection pressure and nozzle diameter can increase oil quantity and injection speed.By using high pressure capacity,high speed camera and other test instruments to test three injection nozzles(0.18 mm,0.22 mm and 0.26mm)in eight fuel injection pressures,and the fuel injection quantity is set in 10 mg and 25 mg.The liquid phases and gas phases are token by directly shoot and shadow-shoot respectively,including liquid phases’ and gas phases’ penetration and triangle.It’s found that,liquid penetration will stop travel when it stops before the saturated penetration.Under the certain quantity of oil and nozzle diameter,the liquid spray at beginning stage penetrates faster by higher injection pressure,while the gas spray penetrates faster at all stage.And the angle of gas spray will be increased with the increase of injection pressure,however,angle of liquid spray will not.In the condition of certain quantity of oil(10mg and 25mg),With the increase of nozzle hole diameter,the penetration distance of liquid spray increases,the average penetration speed of gas spray increases,injection stops earlier.And it’s increased significantly with nozzle hole diameter’s increasing both angle of liquid spray and of gas spray.