Description of Automobile Engines-Principle and working

1. INTERNAL COMBUSTION
Mahesh 1
INTERNAL COMBUSTION
ENGINES

2. •I have always considered that the substitution of the
Internal Combustion Engine for the horse marked a very
gloomy milestone in the progress of mankind.
•-Winston Churchill
Mahesh 2
•If all the perverted ingenuity which was put into
making automobiles had only gone into improving the
breed of horses, we might be a lot better off today.
•-Joe Gould

3. CLASSIFICATION OF HEAT ENGINES
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4. CLASSIFICATION OF I.C. ENGINES
Mahesh 4

5. THEN
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NOW

6. THEN
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NOW

7. History of IC Engines
1860 Lenoir’s engine (a converted steam
engine) combusted natural gas in a
double acting piston, using electric
ignition
Mahesh 7

8.  1876 Nikolaus Otto patented the 4 cycle engine, it
used gaseous fuel
 1882 Gottlieb Daimler, an engineer for Daimler, left to
work on his own engine. His 1889 twin cylinder V was
the first engine to be produced in quantities. Used liquid
fuel and Venturi type carburetor, engine was named
“Mercedes” after the daughter of his major distributor
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 1893 Rudolf Diesel built successful CI engine which
was 26% efficient (double the efficiency of any other
engine of its time)

9. Complementary Technologies for IC
Engine-powered Automobiles
 Pneumatic tires (1888, Dunlop)
 Cheap liquid fuels (Oil industry born in PA 1859)
 Venturi effect carburetor (1892, Willi Maybach)
Variable mechanical transmission (primitive type
Mahesh 9
 Variable mechanical transmission (primitive type
by Levassor, 1891)
 Electric starter (Kettering 1912)

10. Mahesh 10

11.  1860 One-cylinder engine, kerosene- fuel.
 1864 Two-cylinder gasoline engine
 1876 Otto built four-stroke gas engine
 2-stroke engines accomplish the same steps, but less efficiently &
with more exhaust emissions.
 1885 Gasoline-powered engine mounted onto bicycle-
motorcycle &
 1887 First car- included steering tiller & 4- speed gearbox -
Daimler & Maybach
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Daimler & Maybach
 In 1885 German engineer Gottlieb Daimler mounted an engine of
his own design into a wood-framed vehicle.
 The vehicle had 4 wheels, including 2 round stabilizing wheels.
 World’s first motorcycle.

12. CLASSIFICATION OF INTERNAL COMBUSTION
ENGINES
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ENGINES

13. 1. Application
2. Basic Engine Design
3. Operating Cycle
4. Working Cycle
5. Valve/Port Design and Location
6. Fuel
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6. Fuel
7. Mixture Preparation
8. Ignition
9. Stratification of Charge
10. Combustion Chamber Design
11. Method of Load Control
12. Cooling

14. Operating Cycle
 Otto (For the Conventional SI Engine)
 Atkinson (For Complete Expansion SI Engine)
 Miller (For Early or Late Inlet Valve Closing type SI
Engine)
 Diesel (For the Ideal Diesel Engine)
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 Diesel (For the Ideal Diesel Engine)
 Dual (For the Actual Diesel Engine)

15. CLASSIFICATION OF INTERNAL COMBUSTION ENGINES
Mahesh 15

16. Horizontally
Opposed (Subaru)
In Line
(Automobile)
V
(Automobile)
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Radial (Aircraft)
Opposed Piston
(crankshafts geared
together)

17. Mahesh 17

18. Numbering and Firing Order

19. Cylinder Configurations
Straight Configuration
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Straight Configuration
V Configuration
Flat
Configuration
Displacement refers to the
volume inside each piston
chamber. For example: a 3.0
Liter engine with 6 cylinders
will have 0.5 liters per
cylinder.

20. ENGINE NOMENCLATURE
Mahesh 20

21. Parts of an
IC Engine
Air cleaner
Choke
Throttle
Intake manifold
Exhaust manifold
Piston rings
Piston
Wrist pin
Cylinder head
Breather cap
Rocker arm
Valve spring
Valve guide
Pushrod
Sparkplug
Combustion chamber
Tappet
Dipstick
Cam
Mahesh 21
Wrist pin
Cylinder block
Connecting rod
Oil gallery to piston
Oil gallery to head
Crankcase
Crankpin
Crankshaft
Camshaft
Water jacket
Wet liner
Connecting rod bearing
Main bearing
Oil pan or sump

22. Displacement / Clearance Volumes
Mahesh 22

23. Valve Location
Mahesh 23

24. Basic Engine Definitions
 Clearance volume
 Displaced volume
 Compression ratio
Mahesh 24
 Compression ratio

25. Engine Cutaway
Mahesh 25

26. Torque
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Torque = F x b

27. Power = Torque x Angular Speed
Power
P = 2NT
Mahesh 27
P = 2NT
5252
)ftlb(min)/rev(
)hp( F 

TN
P
7045
)(min)/rev( mNTN )kw(P =

28. Gallery of Engines
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29. Mahesh 29

30. Mahesh 30

31. Bore
Stroke
TDC
BDC
Intake
valve
Exhaust
valve
Top Dead Center (TDC) : Upper most position
Bottom Dead Center (BDC) : Lower most position
Stroke : Length of piston travel
Bore : Diameter of the cylinder
Clearance Volume (Vc) : V where piston is at TDC
Displacement Volume (Vd) :Swept Volume (Vmax-Vmin)
Compression Ratio (rv) = (Vmax/Vmin) = (VBDC/VTDC)
Mean Effective Pressure (MEP) :
Wnet = (MEP) x (Displacement Volume)
Diesel engine
Mahesh 31
Diesel engine, Compression Ignition
• Only air is drawn into the cylinder during intake stroke
• fuel is injected into the cylinder after the air is compressed
and the piston reaches TDC
• And continue injecting until reaches “Cut Off Volume, V3”
• Cut off ratio rc = V3/V2 = v3/v2
• Fuel is self ignited as a result of compression.
• Therefore, the Compression Ratio, rv , must be high enough,
Typical rv ~12 – 24
• During the combustion PRESSURE remains constant .
• Others processes are the same as Otto Cycle
• Thermal efficiency of actual Diesel engine ~ 30-40%

32. 4 Cycle Process
Intake
Manifold
Spark
PlugCylinder
Piston
Connecting
Rod Crank
1 2 3
4
Crankcase
Exhaust
Manifold
Exhaust ValveIntake Valve
Mahesh 32
Intake Stroke
Intake valve opens,
admitting fuel and air.
Exhaust valve closed
for most of stroke
Compression Stroke
Both valves closed,
Fuel/air mixture is
compressed by rising
piston. Spark ignites
mixture near end of
stroke.
Power Stroke
Fuel-air mixture burns,
increasing temperature
and pressure, expansion
of combustion gases
drives piston down. Both
valves closed - exhaust
valve opens near end
of stroke
Exhaust Stroke
Exhaust valve open,
exhaust products are
displaced from cylinder.
Intake valve opens
near end of stroke.

33. Mahesh 33

34. ANIMATION OF 4 STROKE ENGINE
Mahesh 34

35. Mahesh 35

36. Mahesh 36

37. Mahesh 37

38. Mahesh 38

39. Mahesh 39

40. Mahesh 40

41. Mahesh 41

42. Mahesh 42

43. Mahesh 43

44. Mahesh 44

45. Mahesh 45

46. 2 Stroke Process
Mahesh 46
Compression
(ports closed)
Air Taken Into
Crankcase
Combustion
(ports closed)
Exhaust
(intake port closed)
Air compressed in crankcase
Scavenging
and Intake
(ports open)

47. Two Stroke
Internal Combustion Engines
Mahesh 47
*How a two stroke engine works
*Advantages/Disadvantages

48. Introduction to the
Two Stroke Engine
 This type of engine is commonly found in
applications such as;
 lawn and garden equipment
 dirt bikes
Mahesh 48
 dirt bikes
 small outboard motors

49. Introduction to the
Two Stroke Engine
 Two stroke engines have advantages over
four stroke:
 simplified construction (no valves)
 fire once every revolution for a significant power
Mahesh 49
 fire once every revolution for a significant power
boost
 Great power to weight ratio

50. The two stroke cycle
 The two stroke engine ignites every
revolution of the crankshaft. These engines
overlap operations to reduce parts while
maintaining power.
Mahesh 50
maintaining power.

51. The two stroke cycle
 After the fuel air
explosion, the piston is
driven down. As the
piston reached the
bottom of it’s stroke,
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bottom of it’s stroke,
the exhaust port is
uncovered. Most of the
gases are driven out.

52.  When the piston has
bottomed out, the
intake port is
uncovered. The new
fuel enters and is ready
The two stroke cycle
Mahesh 52
fuel enters and is ready
for compression and
combustion.

53. The two stroke cycle
 When the fuel mixture
is being compressed a
vacuum is created in
the crankcase. The
vacuum opens a reed
Mahesh 53
vacuum opens a reed
valve and sucks
air/fuel/oil in from the
carburetor.

54. The two stroke cycle
 Simply put, in a two stroke engine you have
only:
 Compression
 Combustion
Mahesh 54
 Combustion
 Thus, Two Strokes.

55. 2 stroke compared to 4 stroke
 In two stroke engines
the crankcase is a
pressurization chamber
to force fuel/oil/air into
the cylinder. Here you
 In four stroke engines
the crankcase is
separate from the
compression chamber.
This allows the use of
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the cylinder. Here you
mix oil and gas to
lubricate internal parts.
This allows the use of
heavy oil for lubrication.

56. Disadvantages of a two stroke
 The engines do not last as long due to poor
lubrication.
 You have to mix two cycle engine oil with
gasoline.
Mahesh 56
gasoline.
 The engines do not use fuel efficiently.
 These engines produce a lot of pollution.

57. Summary
 Two stroke engines are great for the power to
weight ratio and their simple design,
however, due to there pollution concerns
these engines will be harder to find.
Mahesh 57
these engines will be harder to find.

58.  Two-stroke advantages
 Higher power to weight ratio
 Less complicated valve train
Two vs. Four-Stroke Engines
Mahesh 58
 Four-stroke advantages
 More efficient burning process
 As size increases, power-to-weight ratio
improves

59. Rotary “Wankel” Engine
Mahesh 59

60. ANIMATION OF VALVE MECHANISM
Mahesh 60

61. Choke Throttle
How do we get the mixture of fuel and air?
Venturi-type Carburetor
The carburetor of our engine
P+1/2 V2 = Constant
Bernoulli Effect:
Mahesh 61
Fuel
Higher Pressure
Outside Engine
Venturi
Choke Throttle

62. Venturi-type Carburetor in the
car
P+1/2 V2 = Constant
Bernoulli Effect:
Valve StemFuel Inlet
Throttle Plate
Air/Fuel Mixture To Engine
Atomized Fuel
Mahesh 62
Ref. Obert
Constant level is
maintained in bowl -as
float moves down,
valve stem moves down,
allowing more fuel into
bowl, float moves up and
closes valve
Float
Metering Orifice
Choke Plate
Fuel
Nozzle
Inlet Air
Bowl
Venturi

63. How do we initiate the combustion?
Image resource:
http://www.nhsnowmobilemuseum.com/burdicksledshed
/1974%20Alouette%20Super%20Brute%20440.htm
Mahesh 63
But how do we get the spark plug spark?
•Megneto system ( which our engine uses)
•Mechanical ignition
•Electronic ignition
•Engine management system
…………….

64. Anything else important related to
the combustion?
 Think about following situations:
-What will happen if the intake or exhaust valve
are not closed during the compression stroke
(just before the power stroke)?
Mahesh 64
(just before the power stroke)?
-What will happen if the intake or exhaust valve
open during the power stroke?
•Solution?
Right timing of the valves.
The valve mechanism.

65. piston
valve
rocker
valve lifter
push rod
Valve Mechanisms:
How you get the right timing
Image from :
Automotive mechanics, 8th ed. By William H. Crouse
Mahesh 65
valve lifter
camshaft
cam
crankshaft
Timing marks

66. So now you think you can prevent
all the leaking from the cylinder?
Mahesh 66
Piston

67. How do we output the work into
useful energy?
Reciprocating to rotary
motion
Crankshaft
Mahesh 67

68. Anything else to notice?
Piston, crankshaft,
& fly wheel
Mahesh 68
time
Output
torque

69. Have a better idea how engines work?
How does the engine complete these
Primary Functions?
 Get started?
Suck in fuel/air?
Mahesh 69
 Suck in fuel/air?
 Mix air and fuel?
 Ignite the mixture?
 Make the work available to somebody?
 Exhaust the gases?
 Shut off?

70. Have a better idea
how engines work?
How does the engine complete these
Secondary Functions?
Mahesh 70
 Stay lubricated?
 Operate the valves at the right time?
 Smooth out the power pulses?
 Store the fuel?
 Keep cool?
 Make it easy to start?

71. 1971 DeTomaso Pantera Engine
Mahesh 71

72. Mahesh 72
Busch Winston Cup Engine

73. Mahesh 73
Spark Plug Wires

74. Mahesh 74
V-12 330 GT Ferrari Engine Block

75. Mahesh 75

76. Largest Diesel Engine in the World:
The The Wartsila-Sulzer RTA96-C Turbocharged
Two-Stroke Diesel Engine
 Total engine weight: 2300
tons (The crankshaft
alone weighs 300 tons.)
 Maximum power: 108,920
hp at 102 rpmhp at 102 rpm

77. Fuel Injection (electronic, multi-port)
Monitored Engine
Operating Conditions:
Manifold Pressure
Engine Speed
Air Temperature
Coolant Temperature
Acceleration
COMPUTERTRIGGER
Mahesh 77
50 psi typical
INJECTOR DRIVE UNIT
Pressure Regulator Fuel
Filter
Fuel
Pump
FUEL TANK
Injectors

78. Real and Idealized Cycle
Mahesh 78

79. PV DIAGRAM OF IC ENGINE
Mahesh 79