This document discusses fuel injection systems for two-stroke engines as an alternative to carbureted systems. It describes how a typical two-stroke engine works and problems with carbureted systems, such as inadequate scavenging and emissions. The document then covers placement of the fuel injector in the cylinder head or transfer port. It explains how these systems work to inject fuel directly into the combustion chamber or transfer port. Benefits include increased fuel economy, lower emissions and oil consumption compared to carbureted two-stroke engines. Applications mentioned include use in enduro motorcycles.

1. By
Prabhakar j
SNS COLLEGE OF TECHNOLOGY
(AUTONOUMOUS)

2. Contents:
 Introduction
 How normal 2 stroke engine works
 Problems in carbureted 2 stroke engines
 Fuel injection system
 Placement of fuel injector
 Kit to be installed
 Working and lubricating
 Advantages and Disadvantages

3. Introduction
Two stroke are far simple machines than four-
stroke engines . They’re also lighter, easier to work on,
and downright angrier, pumping out a lot more power
per cubic centimetre of displacement, which has won
them a lot of fans.

4. How normal 2 stroke engine works:
 Air and fuel mixed by
carburetor and enters into
crankcase.
 It is send to combustion
camber through transfer port.
 Then combustion takes place.

5. Problems in carbureted 2 stroke
engines
 Overall efficiency is less due to:
1. Inadequate scavenging as some combustion
products remain in cylinder.
2. Loss of fresh charge during scavenging.
3. Less effective compression ratio for same stroke
length.
 It let out huge amounts of emission.
 High lubricating oil consumption

6. Placement of fuel injection system
 In cylinder head
 In transfer port

8. Working
Fuel injector in cylinder head:
 In this method fuel injector is placed at the cylinder
head.
 Fuel is injected directly into the combustion chamber
as the exhaust valve closes.
 Fuel is injected by electronic fuel injector controlled
by ecu.

10. Fuel injector in transfer port:
In this fuel injector is placed in the transfer port
and it is also called as transfer port
injection(TPI).
The fuel is injected directly into transfer port,
so that the upward velocity of air being pump
upward will mist it into the combustion
chamber.

12.  In both system has a power valve that raises and lowers
a flapper valve in exhaust port to help manage power
output.
 When the size of exhaust valve is lowered the engine
will consume less fuel.
 When the size of exhaust valve is raised the engine
gives more power.

13. Lubrication
 In this engine instead of using petroil lubrication
system it uses electronic oil injection system.
 The oil injection system injects oil to the most critical
areas such as crankcase and exhaust valves by an
electronic pump.
 Oil can be replaced as similar to the four stroke
engines

14. Advantages
 Increased fuel economy.
 Low oil consumption.
 More horse power.
 Reduced emission.
 Light weight then four stroke bikes.
 Low noise.

15. Disadvantages
 Complicated operation.
 Less efficient then four stroke commuter bikes.

16. Applications
 Mainly suitable for Enduro bikes.
 Ktm unveils world’s first 2-stroke fuel injected bike.
 Honda is still working to build a two stroke efi bikes.

17. Thank you