this ppt explains the complete working ,parts and all process in 2 stroke engine .for futher details watch videos in youtube. for engineering students please refer foreign author book to develope knowledge .from this 11 slides a complete engine is explained

1. Two-Stroke Engines
ByBy
M.GopinathanM.Gopinathan
311814114018311814114018

2. Two-Stroke

3. Applications
Two stroke engines are found on:Two stroke engines are found on:

Weed trimmersWeed trimmers

SnowmobilesSnowmobiles

Older dirt bikesOlder dirt bikes

ChainsawsChainsaws

Nitro R/C CarsNitro R/C Cars

Small outboardsSmall outboards

Older Jet skisOlder Jet skis

4. The Basics
Two stroke engines operate on the same principles as aTwo stroke engines operate on the same principles as a
four stroke engine.four stroke engine.

Intake- Fuel mixture is drawn intoIntake- Fuel mixture is drawn into crankcasecrankcase duringduring upstrokeupstroke

Compression- mixture is compressed in theCompression- mixture is compressed in the crankcasecrankcase duringduring
downstroke and again during upstroke before combustiondownstroke and again during upstroke before combustion

Combustion-fuel is recompressed and ignited in cylinder duringCombustion-fuel is recompressed and ignited in cylinder during
upstrokeupstroke

Exhaust- burned mixture is forced out byExhaust- burned mixture is forced out by fresh mixture beingbeing
forced in during downstrokeforced in during downstroke
Piston fires once every revolution. No traditional valves like a four-Piston fires once every revolution. No traditional valves like a four-
stroke. Piston serves as a “valve” by covering the ports.stroke. Piston serves as a “valve” by covering the ports.

5. Two-Stroke

6. Upstroke (compression)
One-way valve opens and fuel mixture isOne-way valve opens and fuel mixture is
drawn into crankcasedrawn into crankcase
Transfer port is coveredTransfer port is covered
Fuel mixture is compressed (again) andFuel mixture is compressed (again) and
ignitedignited
Piston covers exhaust port duringPiston covers exhaust port during
compressioncompression

7. Downstroke (Combustion)
Combustion forces piston downCombustion forces piston down
compressing fuel mixture in crankcasecompressing fuel mixture in crankcase
Intake port is covered and valve is forcedIntake port is covered and valve is forced
closedclosed
Transfer port is uncovered forcing fuelTransfer port is uncovered forcing fuel
mixture into cylindermixture into cylinder
This fuel mixture pushes the exhaust outThis fuel mixture pushes the exhaust out
the exhaust portthe exhaust port

8. Two-Stroke

9. Advantages
Less parts = LighterLess parts = Lighter
Fires once every revolution = 2x power ofFires once every revolution = 2x power of
four strokefour stroke
Cheaper, less complex and easier to workCheaper, less complex and easier to work
onon
Can work in any orientation (upside down,Can work in any orientation (upside down,
sideways)sideways)

10. Disadvantages
No dedicated lubrication system (not asNo dedicated lubrication system (not as
durable)durable)
Not fuel efficient and require expensive oilNot fuel efficient and require expensive oil
to be mixed with gas (one gallon oil/1,000to be mixed with gas (one gallon oil/1,000
miles)miles)
Produce a lot of pollution due to burning ofProduce a lot of pollution due to burning of
gas and oil.gas and oil.

11. THANK YOUTHANK YOU