The document discusses the basics of fuel injection systems in compression ignition (CI) engines. It outlines the key objectives of a fuel injection system which are to meter the correct amount of fuel demanded based on engine load and speed, distribute fuel equally among cylinders, inject fuel at the proper timing and rate, and ensure proper atomization. It also provides details on the typical injection timing window and angle. To achieve these objectives, the key functional components are identified as the pumping element to transport fuel, a metering element to control the fuel supply, a metering control to adjust the metering based on load/speed, and a distribution element to divide fuel evenly among cylinders. Finally, it lists some common types of fuel injection systems used in

1. Basics of fuel injection
system in CI Engine
Rampal Singh
B.E. (Mechanical), M.Tech (Production Engineering),
Thrice GATE Qualified

2. Objectives of fuel Injection system
• Metering the quantity of fuel as demanded by load and speed of the
engine
• Distribute the metered fuel equally among cylinders for multi cylinder
engines
• Inject the fuel at correct instant in the cycle
• Inject the fuel at correct rate
• Inject the fuel with spray pattern and atomization as demanded by
engine
• Begin and stop supply of fuel sharply

3. Fuel Injection system in CI ENGINE
• Fuel Injection starts at point a
(20-25 before TDC)
• Fuel injection stops at point B
(20 -25 after TDC)
• Angle of injection = 50 degree

4. To accomplish these objectives, CI Engine
must have following functional components
• Pumping Element – transportation of fuel from fuel tank to engine
cylinder
• Metering element – to measure and control the supply of fuel
demanded by engine
• Metering control- to adjust rate of metering element for change in
load and speed of engine
• Distribution element- to divide fuel equally into all cylinders

5. Types of fuel
injection system in CI
Engines
Air injection system
Air injection system
Solid Injection system
Individual pump and
Nozzle system.
Unit Injector system.
.
Common rail system.
Distributor system
.
Distributor system