1. Fuel Induction Systems for S.I. Engines
P M V Subbarao
Professor
Mechanical Engineering Department
Hardware to Satisfy the Needs of Otto Cycle.…...

2. Thermo-flow Model for Carburetor1

3. One dimensional Isentropic Flow Through A Venturi

4. Reversible Subsonic Flow Nozzle : Venturi
pthroat
p1 = p2s > pthroat p1 p1
p2s p

5. Real Flow Through A Venturi
pthroat
p2a < p2s p1 p1
p2s p
p2a

6. Practical Carburetor Venturi

7. Actual Air Flow Through Venturi
Where
Fuel Flow Through Orifice

8. Carburetor Performance

9. Carburetor Performance

10. Carburetor Performance

11. Control of Equivalence Ratio using Carburetor
p, kPa

12. Modern Carburetor

13. Need for Fuel Injection in SI Engine
One of the main factors to achieve near complete combustion and better engine performance is the generation of a homogenous mixture of air and fuel in the cylinder.
The most of fuel should evaporate in the ports and mix with the inlet air.
Formation a liquid fuel layers at the port and the cylinder walls should be minimized.
The better solution is injection of fuel even in in the inlet port of gasoline (SI) vehicles using MPFI system.

14. Artificial Induction of Fuel
The fuel-induction systems for current (high percentage) spark-ignition engines inject the fuel.
There are both mechanical and electronically controlled injection systems.
Helps in achieving better volumetric efficiency
More uniform fuel distribution
More rapid response to changes in loading conditions
More precise control of the equivalence ratio.

15. Overview of Electronic Fuel Injection System

16. Port Fuel Injection System

17. Control of Wall Wetting in Port Injection

18. The Need for Multi Physics Processes Modeling in Port Injection
Large-scale introduction of
Port Fuel Injection (PFI) in the mid-1980s.
Metered fuel is introduced into each engine intake runner individually with a low-pressure, port fuel injector, by means of a brief injection event during each engine cycle.
Early dynamometer tests indicated that numerous engine performance and emission parameters were significantly influenced by both;
the cone angle of the spray plume and
its direction relative to the back face of the intake valve.

19. Anatomy of EFI
Solenoid Magnet