This presentation discusses the two-stroke engine. A two-stroke engine completes the combustion process in one crankshaft revolution, obtaining one power stroke per revolution. It has fewer parts than a four-stroke engine and is lighter in weight. The basic parts are the piston, piston ring, spark plug, connecting rod, and crankshaft. The working principle is that the intake and exhaust are controlled by piston movement, with the fresh charge entering due to pressure differences and being compressed by the pumping action of the piston. Applications include dirt bikes, lawn mowers, outboard engines, and others.

1. WELCOME TO
MY
PRESENTATION

2. Presentation Topic-
Two Stroke Engine

3. Stroke
 Reciprocating motion used in reciprocating engines and other mechanisms
is back and fourth motion .Each cycle of reciprocation consists of two
opposite motions , there is a motion in one direction and then a motion
back in the opposite direction . Each of this motion is called stroke.

4. 2 stroke
A two-stroke petrol engine is an internal combustion engine that completes
the process cycle in one revolution of the crankshaft . Thus one power stroke is
obtained in each revolution of the crank shaft.

5. Basic parts of 2-stroke petrol engine
 Piston
 Piston Ring
 Spark plug
 Connecting rod
 Crankshaft

6. Spark Plug
 Electronic match is used to begun the combustion process of burning air
and petrol to create heat.
 It provides the means of ignition when the petrol engine’s piston is at the
end of compression stroke close to Top Dead Central (TDC)

7. Connecting rod
 Connects the piston and piston point to the crankshaft

8. Piston
 A sliding plug that harness the force of the burning gases in the cylinder

9. Crankshaft
 Along the piston pin and the connecting rod is converts the up and down
motion ( reciprocating ) of the engine to spinning (rotary) motion

10. Working Principle of 2 stroke
 Here suction and exhaust strokes are eliminated . Instead of valves , ports are
used
 The exhaust gases are driven out of the cylinder by the fresh charge entering
the cylinder
 The intake & exhaust are controlled by movement of piston
 The fresh charge enter to cylinder due to difference of pressure
 The charge is compressed by the pumping action of the piston due to the
design of crankcase
 As the piston continues to move upward , exhaust and transfer port get closed
and the compression is continued
 In the end of the compression the spark is created which ignites the charge and
the products of combustion thrust the piston from TDC to BDC

11. This cycle is repeated continuously

12. Video clips…….

13. Advantages
 The power developed will be nearly twice that of four stroke engine of
same dimension and operating at the same speed
 The work required to overcome the friction of the exhaust and suction
strokes is saved
 Low weight
 Construction is simple
 Low thermal efficiency.
 Can run at higher speeds (5000 rpm)
 Low maintenance cost

14. Disadvantages
 As working on otto-cycle , a part of the fresh mixture is lost through exhaust
port
 Part of the piston stroke is lost
 Heavy consumption of lubricating oil
 Two-stroke engines are not fuel efficient, so we would get fewer miles per
gallon.

15. Use of 2-stroke engine
 Dirt Bike
 Lawn mowers
 Outboard engines
 Chain saws
 Line Trimmers
 Jet Skis
 Snowmobiles
 Model Air Planes
 Light Motorcycles
 Go Karts
 Ultra lights
 Scooters
Go-Karts

16. Example picture-
Dirt Bike Jet Skis
Chain sawsLawn mowers