The document provides an outline for the course ME329: Internal Combustion Engines. It covers three parts: 1) Introduction to ICEs, discussing types of engines and fuel systems. 2) Engine performance parameters and behavior. 3) Engine systems such as fuel, air intake, cooling, lubrication, electrical, emissions control. It also defines key engine components like the piston, crankshaft, valves and their functions in converting combustion energy to mechanical work in the engine cycle.

1. 1
ME329: Internal Combustion Engines
(ICE)
Dr. H. M. Rajabu
hmrajabu@gmail.com
Address: Block-O – Room 010
MIE Dept
SEMESTER-II
Tuesdays: 07:00 – 09:00 (A108)
16:00 – 17:00 (A106)

2. COURSE OUTLINE
Part 1: Introduction to ICEs
• Classification of internal combustion engines
• Air standard cycles, actual engine cycles, p-v diagram
• Spark Ignition (SI) and Compression Ignition (CI) engines
• Two and four -stroke engines
• Indicated and Brake parameters
• Fuels for ICEs
• Spark timing (SI) and fuel injection timing (CI)
• Engine Losses
• Power regulation
• Volumetric efficiency and air capacity of engines
• Engine mechanical and auxiliary friction
• Indicated, brake and friction mean effective pressure
2

3. COURSE OUTLINE
Part 2: Engine performance
• Basic performance parameters
• Engines Performance Behavior (maps)
Part 3: Engine systems
• Fuel and air intake systems
• Cooling system
• Lubricating system
• Electrical system
• Electronic Control Unit (ECU)
• Emission control systems
3

4. 4
Introduction to ICE
What is an engine?
…is a machine designed to convert one form of energy
into mechanical kinetic energy…
Examples of engines:
Petrol engine, Diesel engine, electric motor, wind turbines,
hydro turbines, steam engine, steam turbine, stirling
engine
What is a heat engine?
is an engine that convert thermal energy into mechanical
kinetic energy

5. 5
Introduction to ICE
What is an Internal Combustion Engine
• Is a heat engine in which the heat source is a combustible
mixture of fuel and air that also serves as the working fluid
• The working fluid is used either to:
-Produce shaft work by pushing on a piston or turbine
blade that in turn drives a rotating shaft or
-Creates a high-momentum fluid that is used directly as
propulsive force

6. 6
Introduction to ICE
Engines
Engines
Heat
engines
Internal
combustion
External
combustion
Other types
(electric motors, wind
turbines,..)

7. 7
Introduction to ICE
Why are ICEs so popular and not easily
replaceable?
• They use hydrocarbon fuels (HC fuels have very high energy
density)
• Use fuels with high energy density and can be economically
used in many applications (cars, pumps, etc
• Can be made of various power output (5W – 100 MW)
• Proven technology (the technology has been around for more
than 150 years)
• There is so much demand for motive power in many tasks

8. 8
Introduction to ICE:
Demand for motive power
TRANSPORTATION
CROPS HARVESTING AND PROCESSING

9. 9
Introduction to ICE:
of various power output
FROM VERY BIG ENGINES …TO VERY SMALL ENGINES

10. 10
Introduction to ICE:
Various application of ICEs..1/2
Utility…
Sports and
Entertainment
…
Mobility…
Industry…

11. 11
Introduction to ICE:
Various application of ICEs..2/2

12. 12
Introduction to ICE
Internal and external combustion engines
Heat
engines
Internal
combustion
External
combustion

13. 13
Introduction to ICE
Internal v External…1/8

14. 14
Introduction to ICE
Internal v External…2/8
• Internal Combustion Engines (ICE) are basically
any device which directly uses the hot gases from
combustion of fuel as a working fluid to increase
its temperature and pressure and to create force
and motion.
• Examples of fuels used include: Petrol/Gasoline,
Diesel, Kerosene, Natural gas, Alcohol, Aviation
Gas, biodiesel, vegetable oils…

15. 15
Introduction to ICE
Internal v External…3/8
In External combustion engines (ECE)
• Combustion of the fuel takes place outside the engine
and heats up another fluid such as air or water/steam
which will be a working fluid in an engine.
• The heated fluid then enters the engine to create force and
motion from the gained internal energy.
• Examples are steam engine, stirling engine, steam turbine

16. 16
Introduction to ICE
Internal v External…4/8
In External Combustion Engines
• Working fluid coming out of the engine can be
re-used
Eg: steam engine, steam turbines, stirling engine
• Consists of additional equipment to heat the
working fluid
Eg: boiler to raise steam
....2015Clipsintro

17. 17
Introduction to ICE
Internal v External…5/8
In Internal Combustion Engines
• Heat is added by burning fuel in
air (combustion) inside the
engine cyclinder
• The combusted gases becomes
the working media
• Working media in ICE cannot
be re-used. Why?

18. 18
Introduction to ICE
Internal v External…6/8
Advantages of ECE over ICE are:
• Many type of fuels can be used,
ie, flammable (eg. diesel, petrol,
natural gas) and inflammable (eg.
coal, biomass, cow dung,…).
Solar heating also works. Note:
ICE use only flammable fuels.
• The working media can be re-
used in ECE.

19. 19
Introduction to ICE
examples of ICE and ECE
INTERNAL
COMBUSTION

20. 20
Introduction to ICE:
examples of ICE and ECE
GAS TURBINE (ICE)
....2015ClipsintroHow jet engines work (turbofan
animation).wmv....2015ClipsintroJet Engine
Animation.wmv....2015ClipsintroTurboprop Engine.wmv

21. 21
Introduction to ICE
examples of ICE and ECE
EXTERNAL
COMBUSTION

22. 22
Introduction to ICE:
examples of ICE and ECE
STIRLING ENGINE
(ECE)

23. 23
What is a fuel?
• Fuels are any materials that store energy in the form of
chemical energy that can be released through a reaction
as heat energy
• Most common reaction is combustion of fuel with oxygen
• Combustion is a highly exothermic chemical reaction
• Common fuels which release heat energy via
combustion reaction are biomass (wood, charcoal),
fossil fuels (coal, petrol, diesel, natural gas)
• Nuclear fuels (uranium, plutonium) release heat by
fission or fusion reactions, which in principle is not
combustion.
• Nuclear fuels are used in external combustion engines,
mostly in power plants (Rankine cyle)

24. 24
What is a fuel?
• Why are all internal combustion engines
powered by liquid and gaseous fuels?
– high energy density
– Easy mixing with air (fast combustion)
• Why not use solid fuels in ICE? Eg. Fuelwood,
charcoal, coal, which also have high energy
density?
-not easy to form a homogeneous mixture with air (very
slow combustion)
-abrasion of solids with cylinder walls

25. 25
Other Fuels
• Other types of fuels that can be used in heat
engines:
– Wood (ECE)
– Coal (ECE)
-Biodiesel (ICE and ECE))
-Vegetable oils (ICE and ECE))
-Alcohols (ICE and ECE)
– Natural gas (ICE and ECE)
• any fuel that is used in ICE can be used in ECE,
but not vice versa

26. 26
History of Engines..1/3
• Otto Cycle, basis for petrol engine: Dr. N.A. Otto

27. 27
• Diesel Engine; Dr. Rudolph Diesel
History of Engines..2/3
Dr. R. Diesel

28. 28
• 2-Stroke Cycle Engine; Dugal Clerk
History of Engines -3/3

29. 29
Introduction to ICE
CLASSIFICATION OF HEAT ENGINES
Heat Engines
Internal
combustion
Reciprocating
2 stroke
4 stroke
Rotary
Wankel
engine
Gas
turbines
External
Combustion
Reciprocating
Steam engine
Stirling
engine
Rotary
Steam
turbine

30. 30
Engines classification:
1- mode of combustion
Heat
engines
Internal
combustion
External
combustion

31. 31
Engines classification:
2. working motion
Reciprocating Vs Rotary
• In reciprocating engines, the
linear piston motions are
converted to rotary motion by
mechanical arrangement of
connecting rod and crankshaft
• Rotary engines do not have
many parts, and power
produced is more constant
• Both ICEs and ECEs have
reciprocating and rotary
engines

32. 32
....2015Clips1CON
CEPT WANKEL
MOTOR PT1.mp4.wmv
Engines classification:
2. working motion

33. 33
Engines classification:
3. strokes per cycle
• This classification is for reciprocating
engines only. Rotary engines do not
have pistons and hence strokes
• 4-strokes engines:
-Needs 4 piston motions (strokes)
to complete one “engine cycle”
• 2-stroke engines:
-Needs only 2 strokes to complete
an engine cycle
• ICEs have both 4- and 2-stoke
engines.
• ECEs have 2-stroke engines only

34. 34
Engines classification:
3. strokes per cycle

35. 35
Engines classification:
3. strokes per cycle
• 2- stroke engines

36. 36
Engines classification:
4. Number of cylinders
• Engines can have one or
more working chambers
(cylinders)
• The more the cylinders the
more the engine power
• Limit on the number of
cylinder is crankshaft length
(torsional vibrations, space,
etc)
• All pistons/cylinders have to
share a common crankshaft
Single cylinder engine
Four cylinder engine

37. 37
Engines classification:
5. Cylinder arrangements
• Single-cylinder engines and multi-cylinder engines can have
their cylinders arranged in different orientation and
configuration

38. 38
Engines classification:
5. Cylinder arrangements

39. 39
Engines classification:
6. cooling type
• Engines have to be cooled
because combustion
temperatures are much higher
than the melting temperature of
most metals
• Hence ICEs have to be cooled
to protect material from failure.
• Common cooling methods are
by liquid or air, and can be
classified as such.
• Air-cooled cylinders have
external extended surfaces and
others adds a blowers to
enhance heat transfer to cool
the cylinder surfaces
Air-cooled
liquid-cooled

40. 40
Other Engine classifications:
ENGINES
cooling
cycle
Fuel
No. of cylinders
Cylinder
arrangement
Valve
location
Ignition
fuel
Chamber
design
Other classification:
• Valves Location
• Camshaft location
• Type of ignition
• Type of fuel burned
• Combustion chamber design
• Air induction (natural or turbo
charged)
• etc

41. 41
PISTON
CRANKSHAFT
BLOCK
CONNECTING ROD
FLYWHEEL
Main engine parts: 1/17

42. 42
PISTON
CAMSHAFT
VALVES
Main engine parts: 1/17

43. 43
Basic engine components
and engine operation.
Main engine parts: 1/17

44. 44
4-Stroke Engine working
strokes....2/17
1-Intake stroke
• Air-fuel mixture enters the cylinder
2-Compression stroke
• Mixture compressed
3-Power stroke
• Spark ignites and mixture combust to
high temp.
4-Exhaust stroke
• burned gases out
(NEXT CYCLE)
1-Intake stroke
• Air-fuel mixture enters the cylinder

45. 45
4-Stroke Engine working
strokes....2/17
VALVES OPERATION
-Camshaft operate the valves
-Cam is driven by crankshaft
-Valves are synchronized with piston
position

46. 46
4-Stroke Engine working strokes..3/17

47. 47
4-Stroke Engine....4/17
The 1st stroke-INTAKE:
Events
• Inlet valve opens at TDC (ex.
valve closed)
• Piston moves from TDC to BDC
• Air-fuel mixture enters (pulled)
into the cylinder (for CI engines
only air)
• Inlet valve closed at BDC

48. 48
4-Stroke Engine....5/17
The 2nd stroke-Compression:
• Both Inlet and exhaust valves
closed
• Piston moves from BDC to TDC
• The reduction in volume and
sealing of valves compresses the
trapped mixture
Note: The mixture is more
combustible when compressed

49. 49
4-Stroke Engine....6/17
The 3rd stroke-Power:
Events
• Both Inlet and exhaust valves
remain closed
• Mixture is ignited (or fuel injected
for CI) and it burns, resulting in
high increase of T and P
• The piston is pushed from TDC to
BDC with a tremendous force –
spinning the crankshaft
• The energy in the gases has been
converted to mechanical power
and becomes useless.. Waiting to
be expelled out of the cylinger

50. 50
4-Stroke Engine....7/17
The 4th stroke-Exhaust:
• The exhaust valve opens
• Piston moves from BDC to
TDC
• ..and pushes the burned
gases out of the engine
…ready to repeat the cycle
(intake stroke)

51. 51
4-Stroke Engine....7/17
• ....2015Clips23
D movie - how a
car engine
works.wmv

52. 52
Compression Ignition (CI) engines..8/17
Difference between SI engine (or petrol
engine) and CI engine (or Diesel engine):
• In SI cycle:
>Air and fuel enters the cylinder together
>Both Air and Fuel are compressed together
>Ignition of the mixture is assisted by external
means (spark plug)
• In CI 4-stroke cycle:
> Intake stroke-Air enters the cylinder alone
> Compression stroke – air alone
>Fuel is added inside the cylinder at the end
of compression stroke
> the fuel ignites (no spark) when injected in
hot compressed air

53. 53
Main engine
parts....9/17
Spark plug
• Spark plugs are used in SI engines only
• SI engines needs a source of ignition of
mixture
• a spark gap in a spark plugs located in a
combustion chamber is used to ignite the
air/fuel mixture so that combustion can
occur.
• The spark produced must be strong and it
has to happen at the right moment for the
engine to work properly.
• ....2015ClipsintroSpark Plug
Animation.wmv
• ....2015ClipsintroHow Spark Plug

54. 54
Main engine
parts..10/17
Valves
• The intake and
exhaust valves open at
the proper time to let in
air and fuel and to let
out exhaust.
• They are opened by
the cams in camshaft
and closed by springs

55. 55
Main engine parts
..11/17
Camshaft
• The camshaft has
lobes (called cams)
that push against the
valves to open them
as the camshaft
rotates
• springs on the valves
return them to their
closed position.
• ....2015Clips1Camshaft
& Valve Animation
Training - Automotive
Appreciation Part 2.wmv

56. 56
Main engine
parts..12/17
Piston
• A piston is a flexible side of
combustion chamber that
moves up and down inside
the cylinder.
• It transfers the pressure of
combustion to connnecting
rod (conrod) and crankshaft

57. 57
Main engine parts..13/17
Piston rings
• Provide a sliding seal between
the piston and the cylinder. The
rings serve two purposes:
• They prevent the fuel/air
mixture and exhaust in the
combustion chamber from
leaking into the sump during
compression and combustion.
• They keep oil in the sump from
leaking into the combustion
area, where it would be burned
and lost.

58. 58
Main engine parts..14/17
Connecting rod or
Conrod
• The conrod connects
the piston to the
crankshaft.
• It rotate at both ends
so that its angle can
change as the piston
moves and the
crankshaft rotates.

59. 59
Main engine
parts..15/17
Crankshaft
• The crankshaft
converts the piston's
(up and down) motion
into circular motion.
• Connected directly to
the machine to be
driven, often via a
gearbox

60. 60
Main engine parts..16/17
Sump
• The sump
surrounds the
crankshaft. It
contains oil,
which collects
in the bottom of
the sump (the
oil pan).

61. 61
How fast?..17/17
• How fast?
Normal engine (crankshaft)
rotation is between 600-6000
revolutions per minute (RPM)
!!!
• It means at 600 RPM the
piston takes 50 milliseconds
or 1/20 of a second, to move
from top to bottom!
• …. at 6000 RPM it only takes
5 ms or 1/200 of a second !