1. THERMAL ENGINEERING BY
PRABHAKARAN.T

3. Perfect, good and incomplete combustion

4. THREE T’S OF COMBUSTION
The objective of good combustion is to release all of the heat in the fuel.
This is accomplished by controlling the "three T's" of combustion which are  
(1) Temperature high enough to ignite and maintain ignition of the fuel
(2) Turbulence or intimate mixing of the fuel and oxygen, and
(3) Time, sufficient for complete combustion.
Too much, or too little fuel with the available air in the combustion chamber may potentially result in unburned fuel and carbon monoxide generation.

8. An indirect injection system sprays fuel into the engine  intake  manifold.   Most  gasoline  injection systems are of this type.
Direct injection forces fuel into the engine combustion chambers. Diesel injection systems are direct type.

15. Carburettor….

16. CARBURETOR
The carburetor must do under all engine operating conditions:
Measure the airflow of the engine
Deliver the correct amount of fuel to keep the fuel/air mixture in the proper range
Mix the A/F ratio too finely and evenly

17. Carburetor
It must provide the proper fuel/air mixture across a wide range of ambient temperatures, atmospheric pressures, engine speeds and loads:
Cold start
Hot start
Idling or slow-running
Acceleration
High speed / high power at full throttle
Cruising at part throttle (light load)

18. Fall of the Carburettor
No exact metering of air fuel mixture
No closed loop control which affects the performance of catalytic converter
Drop in volumetric efficiency due to presence of throat and hence low power output
Complicated designs
Variation of a/f ratio across the cylinders due to inertia.
Slow response
Unable to meet emission norms

19. WHY EFI ?
Strict emission standards require precise fuel delivery
ECU used to calculate fuel needs
EFI very precise, reliable & cost effective
EFI provide correct A/F ratio for all loads, speeds and temperature ranges

20. BASIC FUNCTION OF EFI
The process of determining the amount of fuel, and its delivery into the engine, are known as fuel metering
An electronic engine control unit calculates the mass of fuel to be injected
The fuel injector acts as the fuel-dispensing nozzle. It injects liquid fuel directly into the engine's air stream

21. EFI COMPONENTS Injectors Fuel Pump Fuel Pressure Regulator
ECM - Engine Control Module; includes a digital computer and circuitry to communicate with sensors and control outputs
Wiring Harness
Various Sensors:
Crank/Cam Position sensor
MAF sensor/ MAP sensor
Oxygen sensor

22. W h a t i s M P F I ?
It is an electronically controlled injection system in which there is one injector per cylinder placed in the inlet manifold.
It facilitates effective air-fuel ratio for all dynamically varying conditions so that pollution comes down.

24. MULTI POINT FUEL INJECTION

29. INJECTOR

32. COMMON RAIL DIRECT INJECTION
Direct fuel injection evenly distributes fuel throughout the system, from injector to injector.
Pressure generation is decoupled from and independent of engine speed.
The direct injection system can be programmed for optimal performance over the entire engine speed range.

33. THE CRDI DIFFERENCE
In conventional engines, the amount of fuel injected rarely changed in accordance with the demands of the driver.
However, the CRDI engine achieved the set goals by isolating the two functions — generating pressure and maintaining a real-time check on the amount of fuel injected.
Diesel is stored in the common rail at a constant pressure ranging from about 1,600 bar for passenger cars and 1,800 bar for commercial vehicles.
Because of the high pressure injection, the fuel gets atomized finely and quickly which reduces the physical delay associated with the combustion process.

35. How direct injection works
Utilizes a lightweight, compact solenoid requiring less energy to motivate.
Fast solenoid speed permits fine metering of pilot and main injection.
Capability of pressure up to 1600 bar.
Feedback system analyzes the quality of combustion and permits the adjustment of the fuel system.

36. Fuel Rail

38. ADVANTAGES
Low Black Smoke emissions because of 1600 bar system pressure even at low engine speed
Low NOx emissions because of post injection
Low Engine noise because of pilot injection
Cold start capability with Heavy Fuel Oil (HFO)
Fast injector operating enables pilot- and post injection

39. Advantages Contd…
Free control of begin of injection, injection-duration and pressure
High Efficiency because of 1600 bar System
Optimized Combustion development due to independent control of injector opening and closing
Application of special fuel parameters in the engine mapping

40. GASOLINE DIRECT INJECTION

41. GASOLINE DIRECT INJECTION
First French - Aircraft
First Automobile - Bosch - used in Mercedes-Benz 300SL sports car - in cylinder block.
GDI reappeared in Mitsubishi - the first Japanese car
In 2000 VW Lupo - Fuel Stratified Injection (FSI) and Turbo Stratified injection (TFSI)
Fuel injected directly into the combustion chamber
This allows engine to operate in two modes, viz.
Homogeneous mode (Early Injection) - During suction stroke
Stratified mode (Late Injection) - During compression stroke
Combines the advantages of petrol engine and diesel engine

44. Advantages Improved Volumetric Efficiency Increased Compression ratio
Lesser Fuel Consumption and higher power
Upright straight intake ports
Reduced Emissions
Resistance to Pre-Ignition
Improved Throttle response

45. THANK YOU!