What is the importance of tumble ratio in a GDI engine. In my study i can see variation in tumble ratio for different injection timings.
Tumble ratio at what point is more relevant. Either spark or while mixing.
Can anyone suggest me some good references regarding the same.
Hi!
Refer this...
http://www.tandfonline.com/doi/full/10.1080/19942060.2016.1157099
https://www.sciencedirect.com/science/article/pii/S1110016816302988
TR is the ratio of angular speed of flow in certain direction after injection to crank shaft is the angular speed of crank shaft which represents the strength of bulk fluid motion in the engine cylinder. The TR governs the mixture formation and availability of combustible air-fuel mixture near the spark plug The high pressure fuel injection certainly disturbs the bulk motion of the in-cylinder flow. For constant 𝝫 and spark timing the effect of fuel injection pressure on bulk motion of air is negligible because of symmetrical positioning of fuel injector holes about the axis of the injector. TR does not vary much till cerain crank angle degree and for higher combustion chamber volume reduces, which restricts incylinder fluid motion and thus TR reduces. TR is higher at higher engine speeds during the fuel injection phase because of higher piston velocity at higher engine speeds which helps tumble motion.
Thank you for the reply it was really informative. To Dr. Saad & Dr. Mahesh