Through-flow Characteristics Of The Intake Process In Diesel Engine

The intake process is a very important part in the diesel engine working process, itplays a distinguised roles in the total quanity of intake air and the flowing status ofin-cylinder air,which make the intake process have a significant impact on the subsequentspray and combustion process, Thereby affecting the power and fuel economy of thediesel engine. In recent years, with the depth of the study, transient numerical simulationof the inner cylinder flow process has become a hot point in the scholars,researchingamong the world.In this article, the author had done some reseach about the through-flowcharacteristics of the diesel engine intake process. Reseach the fluence of Changing theoperating parameters and the cylinder structure parameters to the through-flowcharacteristics, by using the three-dimensional transient numerical simulation method.Firstly, doing reseach about the variation of the average flow coefficient, inflatablecoefficient and the average swirl ratio of diesel engine, by changing engine speed, strokebore ratio and Intake throat diameter bore ratio. Related variation curve is drawn andanalyzed.Secondly, analyzed the flow conditions inner cylinder at the moment of the end of theintake, including the inner cylinder turbulent situation and the formation and developmentof the swirling motion. Discussed the influence of changeing operating parameters andcylinder structure parameters to the cylinder turbulence and tumble conditions.At last, reseached the scavenging process and development of the cylinder in valveoverlap period, analysed the influence of changing the above parameters to scavengingeffect. Got the variation of scavenging efficiency and scavenging coefficient with theabove parameters, and done the corresponding analysis.Through the study above, have found that, the influence of changing the engine speedto various parameters have strong regularity, this study have strong significance in enginespeed design for the specific through-flow characteristics parameters; The influence of stroke bore ratio and intake throat diameter bore ratio to various parameters is morecomplicated, this study have some guidance in the design of structure parameters forspecific through-flow characteristics, but there are still a lot of work needs a furtherimprovement.