IC Engines- 2 stroke and 4 stroke

i c engine

1. BIRLA INSTITUTE OF BIRLA INSTITUTE OF
TECHNOLOGY TECHNOLOGY
((PATNA CAMPUS)PATNA CAMPUS)
DEPARTEMENT OF MECHANCAL DEPARTEMENT OF MECHANCAL
ENGINEERINGENGINEERING
PRESENTED BY:-
SHIVAM KUMAR (BE/15250/13)
PRAVEEN KUMAR
(BE/15251/13)
ABINASH PANDA
(BE/5271/13)

2. Introduction :Introduction :
 =
•Heat engine : It can be defined as any engine
that converts thermal energy to mechanical work
output. Examples of heat engines include: steam
engine, diesel engine, and gasoline (petrol)
engine.
• On the basis of how thermal energy is being
delivered to working fluid of the heat engine,
heat engine can be classified as an internal
combustion engine and external combustion
engine.

3. Types of EngineTypes of Engine
Internal Engine
Petrol Engine Diesel
Engine






External Engine
Steam Engine
Turbines

4. External Combustion External Combustion
EngineEngine•In an External
combustion engine,
combustion takes
place inside the
cylinder.

• -Steam engine is an
example of external
combustion engine,
where the working
fluid is steam.

5. IC EnginesIC Engines
•In an Internal
combustion engine,
combustion takes place
within the cylinder.
• Petrol engine is an
example of internal
combustion engine,
where the working fluid
is a mixture of air and
fuel .

6. Internal combustion engines may be classified as : Internal combustion engines may be classified as :
–Spark Ignition engines.Spark Ignition engines.
–Compression Ignition engines.Compression Ignition engines.
•Spark ignition engine (SI engine): Spark ignition engine (SI engine): An engine in which An engine in which
the combustion process in each cycle is started by use the combustion process in each cycle is started by use
of an external spark.of an external spark.
•Compression ignition engine (CI engine): Compression ignition engine (CI engine): An engine in An engine in
which the combustion process starts when the air-fuel which the combustion process starts when the air-fuel
mixture self ignites due to high temperature in the mixture self ignites due to high temperature in the
combustion chamber caused by high compression.combustion chamber caused by high compression.
–Spark ignition and Compression Ignition engine Spark ignition and Compression Ignition engine
operate on either a four stroke cycle or a two operate on either a four stroke cycle or a two
stroke cycle.stroke cycle.

7. •Four stroke cycle Four stroke cycle : It has four piston strokes : It has four piston strokes
over two revolutions for each cycle.over two revolutions for each cycle.
•Two stroke cycle Two stroke cycle : It has two piston strokes : It has two piston strokes
over one revolution for each cycle.over one revolution for each cycle.
SI Engine & CI Engine have two
types:-

8. Figure2: Engine components
Engine components :-

9. Internal combustion Engine Internal combustion Engine
ComponentsComponents:-:-
1. Block : Body of
the engine
containing
cylinders, made of
cast iron or
aluminium.

10. 2. Cylinder2. Cylinder

C
A cylinder is the central working part of
a reciprocating engine or pump, the
space in which a piston travels.

11. 3. Head 3. Head :: The piece The piece
which closes the end which closes the end
of the cylinders, of the cylinders,
usually containing usually containing
part of the clearance part of the clearance
volume of the volume of the
combustion combustion
chamber.chamber.

12. 4. Connecting Rod4. Connecting Rod

 In a reciprocating piston engine ,
the connecting rod or conrod connects
the piston to the crank or crankshaft.

13. 5. Piston5. Piston
Piston

The piston of an internal combustion
engine is acted upon by the pressure of
the expanding combustion gases in
the combustion chamber space at the top
of the cylinder.

14. 6. Piston rings6. Piston rings

A piston ring is a metal rings that fit into
circumferential grooves around the piston and
form a sliding surface against the cylinder
walls.

15. 7. Crankshaftt::
Rotating shaft Rotating shaft
through which through which
engine work engine work
output is output is
supplied to supplied to
external external
systemssystems..

16. 8. Camshaft 8. Camshaft ::
Rotating shaft used Rotating shaft used
to push open valves to push open valves
at the proper time in at the proper time in
the engine cycle, the engine cycle,
either directly or either directly or
through mechanical through mechanical
or hydraulic linkage or hydraulic linkage
(push rods, rocker (push rods, rocker
arms, tappets) .arms, tappets) .

17. 9. Intake manifold9. Intake manifold: :
Piping system which Piping system which
deliver incoming air to deliver incoming air to
the cylinders, usually the cylinders, usually
made of cast metal, made of cast metal,
plastic, or composite plastic, or composite
material . In most SI material . In most SI
engines, fuel is added engines, fuel is added
to the air in the intake to the air in the intake
manifold system either manifold system either
by fuel injectors or by fuel injectors or
with a carburetor.with a carburetor.

18. 10. Exhaust 10. Exhaust
manifold manifold :: Piping Piping
system which system which
carries exhaust carries exhaust
gases away from gases away from
the engine the engine
cylinders, usually cylinders, usually
made of cast ironmade of cast iron

19. 11. Spark plug 11. Spark plug : :
Electrical device Electrical device
used to initiate used to initiate
combustion in an combustion in an
SI engine by SI engine by
creating high creating high
voltage discharge voltage discharge
across an across an
electrode gapelectrode gap

20. 12. Flywheel 12. Flywheel : :
Rotating mass Rotating mass
with a large with a large
moment of inertia moment of inertia
connected to the connected to the
crank shaft of the crank shaft of the
engine.engine.
The purpose of The purpose of
the flywheel is to the flywheel is to
store energy store energy ..

21. 13. Fuel 13. Fuel
injector injector :: A A
pressurized pressurized
nozzle that sprays nozzle that sprays
fuel into the fuel into the
incoming air (SI incoming air (SI
engines )or into engines )or into
the cylinder (CI the cylinder (CI
engines).engines).

22. 14. Combustion chamber14. Combustion chamber: : The end The end
of the cylinder between the head and the of the cylinder between the head and the
piston face where combustion occurs . piston face where combustion occurs .
The size of combustion chamber The size of combustion chamber
continuously changes from minimum continuously changes from minimum
volume when the piston is at TDC to a volume when the piston is at TDC to a
maximum volume when the piston at maximum volume when the piston at
BDCBDC

24. Four Stock SI Engine & CI Four Stock SI Engine & CI
Engine Engine :-:-
1. SI Engine:- It this engine, cycle of operation is
completed in four stocks of the piston or two strokes
of crankshaft . Each stroke consists of 180 degree of
crankshaft rotation.
Four strokes are follows:-
A) Suction stroke.
B) Compression stroke.
C) Expansion stroke.
D) Exhaust stroke.

25. 1. Suction stroke:-1. Suction stroke:- In suction stroke fuel-In suction stroke fuel-
air mixture enters in the cylindair mixture enters in the cylinderer

26. 2. Compression Stroke:-2. Compression Stroke:-
compression ratio of petrol engine is 6-10compression ratio of petrol engine is 6-10

27. 3. Power or Expansion 3. Power or Expansion
strokestroke:-:-

28. Exhaust stroke:- Exhaust stroke:-

30. 2. CI Engine:- 2. CI Engine:-
The diesel engine was first patented in 1892 by Rudolph
Diesel. Like SI Engine, CI Engine complete cycle in 4 stroke.
Four stokes are:-
1. intake or suction stroke:-The intake valve
opens, and fresh air (containing no fuel), is drawn into the
cylinder.

31. 2. Compression stroke:- 2. Compression stroke:-
•Both valves stay
closed
•Piston moves from BDC to TDC,
compressing air to 22:1
increases the
temperature inside the
cylinder to above 1000
degree F.
•Compressing the air to
this extent

32. 3. Power stroke:-3. Power stroke:-
•When the piston is at the end of
compression stroke(TDC) the injector
sprays a mist of diesel fuel into the
cylinder.
•Both valves stay closed
•When hot air mixes with
diesel fuel an explosion takes
place in the cylinder.
•Expanding gases push the piston
from TDC to BDC

33. 4. Exhaust Stroke4. Exhaust Stroke
•Piston moves from BDC to
TDC
•Exhaust valve opens and the
exhaust gases escape
•Intake valve remains
closed

34. 2- Stroke Engine2- Stroke Engine
As the name itself implies,
all the processes in the two
stroke cycle engine are
completed in two strokes.
In the two stroke engine
there is a two opening called
ports are provided in place of
valve of four stroke engines.
One port known as a inlet
port and another port is
known as a exhaust port.

35. Working of the two stroke Working of the two stroke
petrol enginepetrol engine
•At the beginning of the first stroke piston
Is at the TDC. Piston moves from TDC to
BDC
First stroke:-
•Another A/F/O mixture is sucked into
crankcase while First one is compressed in
cylinder
Intake/ compression StrokeIntake/ compression Stroke

36. Fig. B
Piston uncovers transfer port
During first stroke
Fig. A
Beginning of the first stroke

37. Second stroke Second stroke :- :- Power/Exhaust Power/Exhaust
StrokeStroke
•In this stroke piston moves from BDC to
TDC.
•Exhaust port is uncovered and
exhaust starts leaving.

38. Fig. C.
Transfer port covered
Fig. D.
Compression commenced

39. •Because it is light, can be used at any Because it is light, can be used at any
angle, operates at high RPM Weed eatersangle, operates at high RPM Weed eaters
Chain sawsChain saws
BoatsBoats
SnowmobilesSnowmobiles
Dirt bikesDirt bikes
Good uses of two stroke Good uses of two stroke
enginesengines

40. 11/2001 40
Usually don’t use 2 strokes Usually don’t use 2 strokes
in :-in :-
Because of pollution, efficiency, lack of low
RPM power, and convenience of not mixing
oil
–Cars
–Trucks
–Road bikes
–Lawn mowers
–Generators

41. Difference between 4 Difference between 4
stroke & 2 strokestroke & 2 stroke
Principle 4 stroke 2 stroke
1.Stroke per cycle
2.Crank rotation per cycle
3.Power stroke per cycle
4.Power
5.Fly wheel
6.Sizeof engine
7.Admission of charge
8.Valves
9.Crankcase
10.Direction of rotation the
crankshaft
11.Lubricant oil consumption
12.Thermal efficiency
13.Mechanical efficiency
14.uses
Four piston stroke
Two crank rotation
Half of speed of crankshaft
In every alternate revolution
Heavy flywheel
Heavier , larger and more
space
Directly into cylinder
Inlet and exhaust valves
It is not hermetically sealed
In one direction
Less
Higher
Low
Cars, tractors, buses
Only two piston stroke
Only one crank rotation
Equal to speed of crankshaft
In every revolution
Lighter flywheel
Lighter , more compact and less space
First admitted into crankcase, then
transfer to engine
In place of valves, ports are there
Hermetically sealed
In both directions
More
Less
High
Mopeds, scooter, motor, cycle

43. Gasoline vs. Diesel EngineGasoline vs. Diesel Engine

44. Wartsila-Sulzer RTA96-C is the largest IC
engine, but the Space Shuttle Solid Rocket
Boosters are the most powerful (≈ 42
million horsepower (32 hp/lb); not shaft
power but kinetic energy of exhaust stream)
Most powerful shaft-power engine: Siemens
SGT5-8000H stationary gas turbine (340
MW = 456,000 HP) (0.52 hp/lb) used for
electrical power generation
Most powerful internal Most powerful internal
combustion enginecombustion engine

45. Safety PrecautionsSafety Precautions
Noise
Fuel Flammability
Maintenance
Water Issues

46. •http://www.small-engines.com/4cycleth.html
•http://en.wikipedia.org/wiki/Engine_displacement
•http://en.wikipedia.org/wiki/Stroke_(engine)
•http://en.wikipedia.org/wiki/Internal_combustion_engine
•http://www.howstuffworks.com/diesel-two-stroke.htm
•http://www.mustangmonthly.com/techarticles/97278_how_engines_work/index.ht
ml
•http://www.kruse-ltc.com/Otto/otto_cycle.php
http://www.kruse-ltc.com/Diesel/diesel_cycle.php
•http://www.answers.com/topic/internal-combustion-engine
http://www.britannica.com/EBchecked/topic/162716/diesel-engine
ReferencesReferences::

47. THANK YOUTHANK YOU