2. Post Injection Process in Port Injection Systems P M V Subbarao Professor Mechanical Engineering Department Models Based Predictions of Multi-physics of Spray …...

3. Frequency diagram of droplets mean diameter Distribution Rosin & Rammler Distribution

4. Representative Mean Diameter Introducing the definition of SMD: where d nozz is the nozzle diameter, μ f, μ g are the fuel and gas dynamic viscosity, respectively, Re the Reynolds number and We the Weber number. German scientist J. Sauter : 1920 Empirical Formula for prediction of possible SMD:

5. Injection Characteristics

6. Fuel Droplet Dynamics : Prediction of Arrival

7. YAMAHA MOTOR TECHNICAL REVIEW Shoichi Kato, Takanori Hayashida, Minoru Iida

8. Proposal - 1

9. Proposal - 2

10. Proposal - 3

11. Proposal - 4

12. Experimental Results to Select Right Arrival Time AFR 14.5, Coolant Temp. 80 ℃ MEP 380 kPa,

13. The System Reliability

14. Flow Simulation Considering the air velocity distribution and distance between the injection nozzle and intake valve, the timing at which the fuel spray reaches the intake valve and enters the cylinder is predicted.

15. Droplet dynamics During the spray penetration, there is a drag force exerted on the droplets from the surrounding gases, which tends to decrease the relative velocity between the drop and the gas flow. From the Newton's Second Law, the equation is: Where d is the droplet diameter, u g and u f are the velocities of the gas flow and the liquid fuel droplet, respectively. And the drag coefficient C D is given as:

17. Droplet Impingement Process

18. Variation of Volume Fluxes

19. Deposited Film Mass Fraction

20. Spray Length

21. Simplified Engineering fuel Evaporation model In a simplified engineering model a representative diameter for the entire group is defined to compute evaporation rate. Equivalent diameter of same number of uniformly sized droplets having same total surface area.

22. Details of Heat and Mass Transfer across Droplet

23. Droplet evaporation The droplet evaporation rate is given by where d is the droplet diameter, D AB the gas diffusivity, Sh* the non-dimensional Sherwood number, and B m the mass transfer number. The mass transfer number B M is equal to: