The document provides a comprehensive overview of internal combustion engines, discussing their classifications based on ignition type, cycle of operation, cooling method, and various components such as the cylinder block, piston, and fuel injection systems. It also details the working mechanisms of four-stroke and two-stroke engines, comparing their performance and applications. Additionally, it covers lubrication systems, governing methods, and properties of liquid fuels used in these engines.

1. BY
G.K. Manikandan
Professor – Department of Mechanical Engineering
SSM College of Engineering, Komarapalayam
Namakkal District – 638183
Tamil Nadu
INTERNAL COMBUSTION
ENGINEES

2. • Gasoline ignited in the small space can
throw a potato upto 500 feet.
Principle Behind An I.C Engine

3. HEAT ENGINE Converts
CHEMICAL ENERGY into THERMAL ENERGY

4. HEAT ENGINES
INTERNAL
COMBUSTION
EXTERNAL
COMBUSTION

5. Classification of I.C. Engines
1. TYPE OF IGNITION
a. Spark ignition b. Compression ignition

6. Classification of I.C. Engines
2. CYCLE OF OPERATION
a. Otto cycle b. Diesel cycle
c. Dual Cycle

7. Classification of I.C. Engines
3. METHOD OF COOLING
a. Air cooled b. Water cooled

8. Classification of I.C. Engines
4. NO. OF STROKES
a. Two stroke – Petrol b. Two stroke - Diesel

9. Classification of I.C. Engines
5. TYPES OF FUEL USED
a. Diesel Engine
b. Petrol Engine
c. Gas Engine
6. TYPES OF LUBRICATION SYSTEM
a. Wet sump lubrication
b. Dry sump lubrication

10. Classification of I.C. Engines
7. VALVE LOCATION
a. L-head b. I-head c. F-head d. T-head

11. Classification of I.C. Engines
8. SPEED OF ENGINE
a. Low speed
b. Medium speed
c. High speed

12. Classification of I.C. Engines
9. NUMBER OF CYLINDERS
a. Single b. Two
c. Three d. Four
e. Six f. Eight
g. Twelve h. Sixteen

13. Classification of I.C. Engines
9. NUMBER OF CYLINDERS

14. Classification of I.C. Engines
10. ARRANGEMENT OF CYLINDERS
a. Inline b. Horizontal
c. Opposed cylinder d. V – type
e. Radial f. Rotary

15. Classification of I.C. Engines
10. ARRANGEMENT OF CYLINDERS

16. Classification of I.C. Engines
IN LINE ENGINE

17. Classification of I.C. Engines
OPPOSED ENGINE

18. Classification of I.C. Engines
V - ENGINE

19. Classification of I.C. Engines
11. METHOD OF GOVERNING
a. Quality
b. Hit and Miss
c. Quantity

20. Classification of I.C. Engines
11. METHOD OF GOVERNING

21. Classification of I.C. Engines
12. FIELD OF APPLICATION
a. Automobile, truck etc.
b. Locomotive engine
c. Stationary engine
d. Marine engine
e. Aircraft engine

22. Classification of I.C. Engines
12. FIELD OF APPLICATION
f. Power Generation
i. Portable ii. Fixed
g. Earth Moving Equipments
i. Dumpers ii. Tippers iii. Mining equipment
i. Home Use
i. Lawn Movers ii. Snow Blowers iii. Tools

23. COMPONENTS & ITS FUNCTIONS
1. CYLINDER BLOCK:
Main supporting structure

24. COMPONENTS & ITS FUNCTIONS
2. CYLINDER HEAD:
Top part of the cylinder block which houses
inlet and exhaust valves.

25. COMPONENTS AND ITS
FUNCTIONS
3. CRANK CASE:
Supports crank shaft and cam shaft with the
help of connecting rod bearings .

26. COMPONENTS & ITS FUNCTIONS
4. OIL SUMP:
Fitted at the bottom of the crank case
containing lubricating oil.

27. COMPONENTS & ITS FUNCTIONS

28. COMPONENTS & ITS FUNCTIONS
5. CYLINDER LINERS:
Materials in the form of sleeves inserted to
cylinder bore to avoid cylinder wear

29. COMPONENTS & ITS FUNCTIONS
6. PISTON:
Cylindrical shaped mass
reciprocating inside the cylinder.

30. COMPONENTS & ITS FUNCTIONS
7. PISTON RINGS:
Used to maintain airtight sealing between
piston and cylinder to prevent gas leakages
.

31. COMPONENTS & ITS FUNCTIONS
8. CONNECTING ROD:
Used to connect piston and crank shaft
with the help of bearings..

32. COMPONENTS & ITS FUNCTIONS

33. COMPONENTS & ITS FUNCTIONS
9. CRANK SHAFT
Used to covert reciprocating motion of piston
to rotating motion.

34. COMPONENTS & ITS FUNCTIONS
9. CRANK SHAFT

35. COMPONENTS & ITS FUNCTIONS
9. CRANK SHAFT

36. COMPONENTS & ITS FUNCTIONS
10. CAM SHAFT
Used to convert rotary motion of cam shaft into
linear motion of lifter.

38. COMPONENTS & ITS FUNCTIONS
11. SPARK PLUG:
Used to ignite air-fuel mixture after completing
compression stroke in petrol engine.

39. SPARK PLUG

40. COMPONENTS & ITS FUNCTIONS
12. FLY WHEEL:
Perfectly balanced wheel usually connected to
rear end of crank shaft.

41. COMPONENTS & ITS FUNCTIONS
13. VALVES
• Used for closing and opening
passage of cylinders.

43. WORKING OF 4-STROKE
(S.I.) PETROL ENGINE
1. SUCTION STROKE:
• Piston moves from TDC to
BDC.
• Inlet valve opens
• Air fuel mixture enters into the
cylinder.

44. WORKING OF 4-STROKE
(S.I.) PETROL ENGINE
2. COMPRESSION STROKE:
• Both valves close.
• Piston moves from BDC to TDC.
• Temperature of compressed air
reaches about 600 to 700
o
C.

45. WORKING OF 4-STROKE
(S.I.) PETROL ENGINE
3. POWER STROKE:
• Fuel injector opens
• Fuel injects at the starting of
this stroke.
• Due to combustion, piston is
moved to BDC.

46. WORKING OF 4-STROKE
(S.I.) PETROL ENGINE
4. EXHAUST STROKE:
• Exhaust valve opens.
• Piston moves from BDC to TDC.
• It blows out burnt gases from
cylinder

47. WORKING OF 4-STROKE
(S.I.) PETROL ENGINE

48. WORKING OF 4-STROKE
(S.I.) DIESEL ENGINE

49. 2 STROKE PETROL ENGINE
1. FIRST STROKE: (SUCTION
AND COMPRESSION)
• Piston moves from BDC to
TDC.
• Fuel enters into the cylinder
through suction port.
• At the end of first stroke
compression & ignition takes
place

50. 2 STROKE CYCLE ENGINE
2. SECOND STROKE:
(EXPANSION AND EXHAUST)
• Piston moves from TDC to BDC
due to the power produced by
combustion.
• Same time exhaust port opens
and burnt gases exhaust.

51. 2 STROKE CYCLE ENGINE

53. THEORETICAL P –V DIAGRAM
4 STROKE - OTTO CYCLE ENGINE

54. ACTUAL P –V DIAGRAM
4 STROKE - OTTO CYCLE ENGINE

55. THEORETICAL P –V DIAGRAM
4 STROKE - DIESEL CYCLE ENGINE

56. ACTUAL P –V DIAGRAM
4 STROKE - DIESEL CYCLE ENGINE

57. P –V DIAGRAM
2 STROKE DIESEL - CYCLE
THEORETICAL ACTUAL

58. P –V DIAGRAM
2 STROKE PETROL ENGINE
THEORETICAL ACTUAL

59. THEORETICAL VALVE TIMING
DIAGRAM
4 STROKE – OTTO ENGINE

60. ACTUAL VALVE TIMING
4 STROKE – OTTO ENGINE

61. ACTUAL VALVE TIMING
4 STROKE – DIESEL ENGINE

62. PORT TIMING DIAGRAM
2 STROKE CYCLE ENGINE

63. COMPARISON OF
4 STROKE & 2 STROKE
ENGINES

64. 1. COMPLETION OF CYCLE
4 S – One Power troke in 2 revolutions
2 S – One Power stroke in each revolution
2. FLY WHEEL
4 S – Heavier
2 S – Lighter

65. 3. POWER PRODUCED FOR SAME ENGINE
SIZE
4 S – Less
2 S – More
4. VALVE AND VALVE MECHANISM
4 S – Valves are Present
2 S – Only Ports are Present

66. 5. COOLING AND LUBRICATION
4 S – Lesser Cooling & Lubrication
2 S – More Cooling & Lubrication
6. VOLUMETRIC EFFICIENCY
4 S – Higher due to more time of of induction
2 S – Lesser due to less time of of induction

67. 7. THERMAL EFFICIENCY
4 S – Higher
2 S – Lower

68. COMPARISON OF
SPARK IGNITION
&
COMPRESSION IGNITION
ENGINES

69. 1. THERMODYNAMIC CYCLE
S.I : Otto
C.I : Diesel for Slow Speed Engines
Dual for High Speed Engines
2. FUEL USED
S.I : Petrol
C.I : Diesel

70. 3. AIR FUEL RATIO
S.I : 10 : 1
C.I : 18 : 1
4. COMPRESSION RATIO
S.I : 7 to 9 Limited by knocking
C.I : 15 to18 Limited by Thermal & Mechanical Stresses

71. 5. FUEL SUPPLY
S.I : Carburettor
C.I : Injection
6. OPERATING PRESSURE
S.I : Compression Pr: 7 to 15 bar
Max Pr : 30 to 50 bar
C.I : Compression Pr: 30 to 50 bar
Max Pr : 60 to 120 bar

72. 7. CONTROL OF POWER
S.I : Quantity governing – by Throttle
C.I : Quality governing – by Rack
8. RUNNING COST
S.I : High
C.I : Low

73. 9. MAINTENANCE COST
S.I : Low
C.I : High
10. APPLICATIONS
S.I : Motor Cycles, Cars, Aircrafts
C.I : Buses, Trucks, Locomotives, Tractors, Gen Sets etc.

74. FUEL SUPPLY SYSTEM
PETROL ENGINES

75. SIMPLE CARBURETTOR

76. OPERATING CONDITIONS OF
S.I. ENGINE
1. STEADY RUNNING
Continuous operation at a given Mean Speed
2. TRANSIENT OPERATION
 Starting
 Warming
 Idling
 Acceleration & Loading

77. ZENITH CARBURETTOR
1. STARTING JET
- Provides Rich Mixture
2. COMPENSATING JET
- Reduces the Mixture Richness
3. ACCELERATION
- Provides Rich Mixture

78. ZENITH CARBURETTOR

79. FEED PUMP FOR CARBURETTOR

80. FUEL SUPPLY SYSTEM
DIESEL ENGINES

81. REQUIREMENTS OF FUEL
INJECTION SYSTEM
INJECTION OF
• Constant Supply of Fuel for Each Cylinder / Cycle
• Fuel at the correct time / correct quantity
• Change the Qty of fuel according to the Load
• Atomize the fuel

82. INJECTION SYSTEM TYPES
1. Air Injection
2. Air – Less or Solid or Mechanical injection

83. COMMON RAIL SYSTEM

84. DISTRIBUTOR SYSTEM

85. INDIVIDUAL PUMP & NOZZLE
SYSTEM

86. FUEL PUMP

87. FUEL ATOMISER / INJECTOR

88. IGNITION SYSTEM
PETROL ENGINES
BATTERY OR COIL IGNITION SYSTEM
&
MAGNETO IGNITION SYSTEM

89. PRINCIPLE OF INDUCTION

90. BATTERY / COIL IGNITION
SYSTEM

91. MAGNETO IGNITION SYSTEM

92. COOLING SYSTEM
AIR COOLING
LIQUID COOLING

93. AIR COOLING

94. LIQUID COOLING

95. 1. THERMO – SYPHON
Water becomes light on heating

96. 2. FORCED / PUMP SYSTEM

97. 3. THERMOSTAT COOLING

98. Thermostat

99. PRESSURISED WATER COOLING
• Water Pressure is Kept between 1.5 to 2.0 bar
• Vacuum valve is used to avoid vacuum
formation when engine is stopped
• Pressure relief valve is used

100. EVAPORATIVE COOLING

101. LUBRICATON SYSTEM

102. NECESSITY OF LUBRICATION
Reduce friction & Wear and Tear
Cool the surface
Seal the space between two surfaces
Absorb shock between bearings and
other parts

103. PROPERTIES OF LUBRICANTS
• Viscosity
• Fire Point
• Flash Point
• Pour Point

104. PROPERTIES OF LUBRICANTS
• Cloud Point
• Corrosion
• Film Strength
• Oiliness
• Emulsification

105. PARTS TO BE LUBRICATED
• Piston rings & Cylinder walls
• Main Crankshaft bearings.
• Camshaft and its bearings

106. PARTS TO BE LUBRICATED
• Big – end bearings
• Small end Gudgeon Pin bearings
• Timing Gears
• Valve guides, tappet, rocker arms

107. TYPES OF LUBRICATION
SYSTEM
1. WET SUMP
a. Splash
b. SemiPressure
c. Full Pressure
2. DRY SUMP
3. MIST

108. WET SUMP LUBRICATION SYSTEM

109. WET SUMP - SPLASH

110. WET SUMP – SEMI PRESSURE

111. WET SUMP – FULL PRESSURE 1.5 – 4 bar

112. DRY SUMP 3 – 8 bar

113. MIST LUBRICATION SYSTEM
• Used for 2 STROKE Engines
• 2 – 3 % of oil is added to the fuel

114. MIST LUBRICATION SYSTEM
Advantage:
Low Cost
Disadvantage:
A Portion of oil is burnt
Oil Loses its anti corrosion properties

115. GOVERNING OF I.C ENGINES
 Keeping the Engine Speed CONSTANT
when LOAD on the Engine CHANGES
 This is Performed by a GOVERNOR which
CONTROLS the FUEL SUPPLY SYSTEM

116. GOVERNING OF I.C ENGINES
1. Hit and Miss Method
Used in Gas Engines
2. Quality governing
Mixture Strength is altered
3. Quantity governing
Quantity of Mixture entering the
cylinder is altered

117. PROPERTIES OF LIQUID FUEL
1. Self Ignition Temperature
Depends on Pressure
2. Calorific value
Should be High
3. Enthalpy of vaporization
Should be Less
4. Volatility
Promotes Fast Reaction

118. LIQUID FUELS FOR RECIPROCATING
COMBUSTION ENGINES

119. LIQUID FUELS FOR RECIPROCATING
COMBUSTION ENGINES