This document provides an introduction and overview of heat engines and their classification and components. It begins by defining heat engines and discussing their classification into internal combustion engines, external combustion engines, and other types. It then covers the basic operation and components of two-stroke and four-stroke engines. The rest of the document discusses engine systems like fuel, intake/exhaust, lubrication, and cooling systems. It also defines common engine terms and concepts.

1. Presented By:-
Er. Narendra Kumar Yadav

2. Objectives
• Introduction to heat engines
•Classification of engines
• Operation of systems
• Two stroke engines
• Four stroke engines
• Components and purposes of each
• Different systems of the engine

3. It is a device which converts the thermal energy
of the working substance into useful
mechanical energy
Or
Engine converts chemical energy into
mechanical energy
Or
A machine with moving parts that converts
power into motion.

4. About the Inventor
In 1893, German inventor Rudolph Diesel
developed the first single-cylinder diesel engine.
In fact it is a compression-ignition engine.

5. Classification of Heat Engine
Heat engine
EC Engine
(Steam Engine)
IC Engine
Wankel Engine
Rotary Turbine
Engine
Reciprocating
Engine
CI Engine
(Diesel)
SI engine
(Petrol)
2- Stroke 4- Stroke 2- Stroke 4- Stroke

6. EC ENGINE
Combustion chamber
Piston
Cylinder
Hot air

7. 4 stroke ENGINE
Exhaust valve
Inlet valve
2 stroke ENGINE
IC ENGINE
Exhaust port
Inlet port
Fuel +
air
Crank shaft
Connecting rod

8. Engine Classification
 Engine Cycle
 Number of stroke
 Fuel Used
 Types of Ignition
 Number & Arrangement of
Cylinder
 Valve Arrangement
 Types of Cooling

9. 1. Suction
2. Compression
3. Power
4. Exhaust
Four stroke Engine

10. Stroke Suction
Piston
movement
TDC to BDC
Valve
position
In Open
Ex Close
Action
Air is sucked
in

11. Stroke Compression
Piston
movement
BDC to TDC
Valve
position
In Close
Ex Close
Action Air is compressed

12. Stroke Power
Piston
movement
TDC to BDC
Valve
position
In Close
Ex Close
Action
Diesel is injected
& explosion

13. Stroke Exhaust
Piston
movement
BDC to TDC
Valve
position
In Close
Ex Open
Action Exhaust is out

14. Two stroke
 Upward stroke
Intake / suction stroke
Compression stroke
Power stroke
Exhaust stroke
 Downward stroke

15. Two vs. Four-Stroke Engines
Two-stroke advantages
• Higher power to weight ratio
• Less complicated valve train
Four-stroke advantages
• More efficient burning process
• As size increases, power-to-weight ratio
improves

16. 3D Model of Single Cylinder Engine

17. General Definitions
What is work?
work is changing of position of an object
against an opposing force.
distance times force equals works.
distance x force = work.
Unit of work : ft.lb or mkg.
What is torque?
force x distance = work.
Unit of torque : lb.ft or kgm.

18. Torque
Torque is twisting or turning effort. You apply a
torque to steering wheel to turn.
Do not confuse…
Torque is the twisting effort engine applies
through the shaft and gears to the wheels.
Power is the rate at which engine works. Both
work & power indicate motion.
Torque does not implies motion, it is a turning
effort which may or may not result in motion.
General Definitions

19. What is Power?
Power is rate of doing work. This defines how
fast a tractor can do the work.
The SI unit for power is the watt.
General Definitions

20. Horse Power
years ago , when engines
were being developed, their
ability to do work was
compared with the ability of
a horse.
A 10 hp engine, for example, could do the work of 10
horses.
James Watt noticed that a horse walks 100 feet in 1
minute lifting the 330 lbs. weight in the mines. A
horse power , therefore , was considered to be 100 x
330 = 33000 ft.lb. per minute.
General Definitions
100 Feet in
1 minute
330 Lbs

21. Horsepower
This is the unit of power. Power is rate of
doing work. This defines how fast a tractor
can do the work.
HP = British Horse Power = 745.7 watts.
PS = Metric Horse Power = 735.5 watts.
PS : Pferde Starke { German word }
1 HP = 1.014 PS
1 PS = 0.985 HP.
General Definitions

22. Low idle
Even to operate a engine without any load,
certain HP is required to run Water pump, Fuel
pump, Alternator, piston, timing gears, crank shaft
etc. Low idle is the RPM at which the engine
produces just enough HP to keep rotating these units
& sustain its motion without vibration.
It is - no load, no speed situation & accelerator
pedal is not pressed.
General Definitions

23. High idle
It is maximum speed of engine at no load
condition. It is - no load & accelerator pedal
fully pressed situation.
For 245 engine - High idle is 2140 - 2190 rpm.
Rated RPM
It is the RPM at which the engine can produce
maximum power.
It is - full load & accelerator pedal fully
pressed situation.
General Definitions

24. TDC
Top Dead Centre - the
highest point the piston
reaches.
BDC
Bottom Dead Centre -
the lowest point the
piston reaches.
Bore :- It is the Internal diameter of the liner.
Stroke:- Length from BDC to TDC.
General Definitions

25. Swept Volume
Volume swept by piston
from BDC to TDC.
Clearance Volume
Volume above the piston
crown { head } when the
piston is at TDC.
Swept Volume + Clearance Volume
Compression Ratio = --------------------------------------------------
-
Clearance Volume
General Definitions

26. Volumetric Efficiency
Ratio of actual volume of air sucked by engine to
theoretical volume.
Actual volume is less due to
time problem.
bends in the air cleaner , pipes.
inlet manifold shape.
air is heated due to engine heat reduces
mass of air.
Volumetric efficiency drops at higher speed due to
less time available . That is why HP curve drops. At
higher speed , the volumetric efficiency drops to
approximately to 80%.
General Definitions

27. Thermal Efficiency
Ratio of Power output & the energy in fuel burned to
produce this output.
It is also to be noted that, total heat generated is used
for:-
- About 30-35% lost in cooling system.
- About 30% lost in exhaust.
- About 10% lost in friction.
- About 20-33% of total heat producing brake
power
(useful work).
General Definitions
Mechanical efficiency
BHP
Mechanical efficiency = ---------- x 100
IHP

28. Tappet clearance
It is the clearance between
the rocker arm & tip of the
valve.
General Definitions
Inlet 0.004"
Ex. 0.006"
235 DI

29. Injection Timing
Theoretically, diesel is injected at TDC at the end of
Compression stroke.
But for complete burning of fuel, mixing of fuel with air is
very important. Moreover delivery of fuel also takes
some time.
So , to deliver the fuel in the cylinder & allow it to mix
with air properly, fuel is injected before end of
Compression Stroke at TDC.
General Definitions

30. Cubic Capacity or Displacement
It is the maximum air breathing capacity per
suction stroke of the engine. Generally given in
cubic-cm {cm3}.
1,000 cc = 1 liter.
General Definitions

31. Firing order
It is the sequence in which combustion is
initiated in the cylinder.
To obtain good distribution of the fuel to all
cylinders, it is desirable and usual to arrange the
induction alternately in the front & rear half of the
engine.
Uniformity in ignition interval, ease of crank
shaft manufacturing, optimal crank shaft load pattern
etc. all play a role in defining firing order.

32. Firing order sequence
1 – 3 – 6 – 8 – 4 – 2 – 7 – 5
1 – 4 – 7 – 3 – 8 – 5 – 2 – 6
1 – 3 – 2 – 5 – 8 – 6 – 7 – 4
1 – 6 – 2 – 5 – 8 – 3 – 7 – 4
8 cylinder
1 – 2 – 4 – 6 – 5 – 3
1 – 4 – 5 – 6 – 3 – 2
1 – 4 – 2 – 6 – 3 – 5
1 – 5 – 3 – 6 – 2 – 4
6 cylinder
1 – 2 – 4 – 5 – 3
5 cylinder
1 – 2 – 4 – 3
1 – 3 – 4 – 2 mahindra
4 cylinder
Inline
Engine

33. Engine Timing

34. IHP– Indicated Horse Power
(Theoretical HP)
FHP– Frictional Horse Power
(Losses)
BHP– Brake Horse Power
BHP= IHP– FHP.
Prony brake Dynamometer was used to
measure engine output.

35. POW ER CALCULATION:
PLANK
IHP= --------------------
33000
P= mean effective pressure in psi.
L=length of stroke in feet.
A=areaof cylinder in square inch.
N=no. of power stroke per minute ( rpm / 2)
K = no of cylinder.

36. Backup Torque :
It is the ability of the machine
to keep working as the engine
pulls down due to increased
load requirements over
and above the maximum power.
Max.Torque – Torque at Max.power
Back up Torque = --------------------------------------------------- x
100% Torque at max. Power
General Definitions

37. General Definitions
Backup Torque : is reserve torque available
so that when the load increases
1. No gear change required.
2. No increase in engine speed required.
3. No need to lift the implements.

38. General Definitions
The fuel consumption of a tractor depends on
many factor like load, speed, driving habits, type of
implements, soil condition, road condition etc. and
very difficult to measure in field conditions.
Fuel consumed/ min
SFC = --------------------------
BHP
Specific Fuel Consumption - SFC

39. General Definitions
Drawbar Horsepower or Pull
Drawbar horsepower is the power available at
the drawbar of the tractor after reduction of
horsepower due to losses at various stages, and
is much less than the claimed horsepower.

40. Engine
Components

41. Engine Block
 Metal foundation
 Supports crankshaft and usually camshaft
made of cast iron or aluminum, aluminum parts
that wear will have metal inserts that are
pressed or cast into the block.

42. Cylinder Sleeves
 Round pipe like liners

43. Piston
 Sliding plunger in cylinder creates vacuum on
intake stroke, compresses mixture on
compression stroke transmits and contains the
pressure of the firing stroke, cleans the cylinder
of burned gases on the exhaust stroke.

44. Piston Pins
 Steel pin used to connect piston to connecting
rod
 case hardened, soft center 0.004 outside
hardened highly polished

45. Types of Piston Pins:
a) Fixed pin
b) Semi floating pin
c) Full floating pin

46. Piston materials
 Aluminum - cast - most common,
 Forged- found in hi-performance engines

47. Piston rings
Compression ring and Oil ring

48. Heat dam
 Groove in head of piston that prevents or
lowers the amount of heat transferred to the
top ring
 Top ring groove insert, metal insert cast into
aluminum piston with piston groove cut out
of insert to help prolong the life of the piston

49. Connecting Rods
 Connect piston to the crankshaft upper end oscillates
lower or large end rotates lower end must be split for
installation of bearing and installation on crankshaft
journal. before removing number rod and rod cap on
same side with a number.

50. Connecting Rods
 Steel Rod Aluminum Rod

51. Insert Bearings
 Removable bearing split in two pieces for
easy installation and removal

52. Insert Bearings
 Steel back with soft lining, coating can be of
babbitt, copper-lead-tin or aluminum coating
 locating tabs help keeps insert bearing from
turning

53. THRUST
BEARINGS
 Thrust bearing, has sides on to help prevent end
play of crankshaft, sometimes use a separate
piece for the side.

54. Crankshaft
 Crankshaft, change reciprocating motion to
rotary motion
 made of Forged steel (should ring when you
hit it with a hammer) or cast iron
 counter balances, forged in crank to offset
weight of crankshaft throw

55. Crankshaft
 Crankshaft throw, the part of crankshaft that
the connecting rod fastens to also refer to as
rod journal
 Crank main journal, by use of main bearing
caps crankshaft is bolted to block
 Crankshaft is drilled so oil can be fed to main
bearings and rod bearings, crankshafts are
ground and highly polished

56. Flywheel
 1. smooth out engine speed
 2. mounting surface for clutch
 3. starter motor engage ring gear to start engine
 4. carry engine through power strokes

57. Camshaft
 opens the valves in engine cam lobes open the
valves one per valve shape of lobe determines
how long valve stays open and how far it
opens also gear to drive the distributor and oil
pump an eccentric may be ground or bolted
onto cam to drive the fuel pump

58. Timing chain, belt and
gears
 Drive chain or belt that connects the crankshaft
gear(driving force) to the cam shaft gear (the
driven force) camshaft turns at 1/2 crank shaft
speed.
 light duty chain, heavy duty - double roller,
driven by all gears, crank gear - steel, cam
gear - steel, aluminum, pressed fiber, plastic,
must be aligned

59. Timing chain

60. Timing gears

61. Valves
 Device used to open and close
the valve port, engines have 2, 3
or 4 valves per cylinder
 some valves have a special hard
facing on the face stellite faced
valves
 Valve faces are ground at different
angles 29-30 and 44-45 most
common.

62. Valve seat
 Part of head or block that valve face comes in
contact with to seal cylinder. Can be part of
head or an insert that is pressed in. most now
are hardened seats valve seat angle 30 and
45.
 Cooling, heat dissipates through valve seat
and valve guide some valves (heavy duty
truck) are sodium filled to help transfer heat.

63. Valve springs
 closes valve when lifter comes off cam lobes
some valves use 2 springs per valve, Must
measure valve spring installed height, coil bind -
spring can only go together so far.

64. Valve spring
retainer
 Holds spring in place with a valve lock or
keeper

65. Valve keepers
 holds valve in place maybe called a stem lock

66. Valve guide
 hole through which valve
passes to keep it in proper
alignment can be cast into
head or pressed in must
have 0.002 - 0.003
clearance

67. Valve lifter/ Tappet/ Cam
follower
 Mechanical - solid
 lifters are solid or hollow made
of cast iron bottom that
contacts camshafts is
hardened adjustment is taken
care of in rocker arms on most
engines some lifters are
adjustable.

68. Rocker Arm
 Transmit cam lobe action to the valve stem,
two type adjustable and non adjustable can be
mounted on shaft or a individual stud,
overhead cam-rocker arm operates on
camshaft (eliminates the middle man), roller
rockers

69. Push rod
 Transmits valve train motion from valve lifter to
rocker arm

70. Crank case or oil pan
 Reservoir for oil usually made of stamped steel
attached to the bottom of block the oil pump is
usually with in this reservoir.

71. Engine system
 Fuel system
 Intake and exhaust system
 Lubrication system
 Cooling system
 Governing system

72. Fuel system
 Fuel storage tank
 Fuel transfer pump
 Fuel filter
 Injection pump
 Injection nozzles or injectors

73. Fuel system

75. The major parts of the diesel fuel system are . . .

76. The major parts of the diesel fuel system are . . .
OPTIONAL

77. The major parts of the diesel fuel system are . . .

78. The major parts of the diesel fuel system are . . .

79. The major parts of the diesel fuel system are . . .

80. The major parts of the diesel fuel system are . . .

81. The major parts of the diesel fuel system are . . .

82. MDI – 4 cylinder Fuel system layout

83. The diesel fuel injection system must :
WHAT FUEL INJECTION MUST DO
1 Supply the correct quantity of fuel.
2 Time the fuel delivery.
3 Control the delivery rate.
4 Break up or atomize the fuel.
5
Distribute fuel evenly through the
cylinder.

84. WHAT FUEL INJECTION MUST DO
1 Supply the correct quantity of fuel.
The fuel system must supply the exact amount
of fuel to each cylinder, each and every time.
2 Time the fuel delivery.
Fuel delivered too early or too late during the
power stroke causes a loss of power.
3 Control the delivery rate.
Delivery Rate - Smooth operation from each
cylinder depends on the length of time it takes to
inject the fuel. The higher the engine speed the
faster the fuel must be injected.

85. WHAT FUEL INJECTION MUST DO
4 Break up or atomize the fuel.
Fuel Atomization - The fuel must be thoroughly
mixed with the air for complete combustion. For
this reason the fuel must be broken up into fine
particles.
5 Distribute fuel evenly through the cylinder.
The fuel must be spread evenly in the cylinder to
unite with all the available oxygen. This makes
the engine run smoothly and develop maximum
power.

87. Feed pump for supplying the fuel from the fuel tank to the
suction gallery of fuel injection pump through fuel filter.

88. hand primer
feed pump FILTER

89. Cleaning fuel feed pump filter
Cleaning fuel feed pump filter
i Close the fuel cock.

90. Cleaning fuel feed pump filter
Cleaning fuel feed pump filter
i Close the fuel cock.
ii
Remove the feed pump bowl by rotating in
anticlockwise direction.

91. Hand primer
The hand primer is screwed
into the feed pump above the
suction valve. With the aid of
the hand primer the fuel can be
pumped from the fuel tank
through the filter to the fuel
injection pump when the
engine is at rest. The quantity
delivered per stroke is about 6
cm3.
Accessories

93. Type of MICO Fuel filter inserts – old design
Secondary
Primary
Star type Paper insert
Cloth type insert

94. Type of MICO Fuel filter inserts – New design
Secondary
Primary
Coil type Paper insert
Cloth type insert

95. Type of MICO Fuel filter inserts – Current design
Secondary
Primary
Coil type Paper insert
Coil type Paper insert
# Primary & Secondary Fuel filter inserts are not same.
10  5 

96. Fuel Injection Pump
Functions:
 Supply correct quantity of fuel
 Time the fuel delivery
 Control the rate of delivery
 Atomize the fuel
 Distribute the fuel

97. Injection nozzles
 Atomized the fuel for the better combustion
 Spread the fuel spray to fully mix it with the air

98. Intake and exhaust system
Intake system
 Air cleaner
 Supercharger
 Intake manifold
 Intake valve
Exhaust system
 Exhaust valve
 exhaust manifold
 Turbocharger
 Muffler

99. Or another way to increase mass of air without
increasing the size of engine is to have a Air Pump
in the system for air as we have Fuel Pump for the
fuel.
This Air Pump will suck the air from air cleaner,
pressurized it, and then send it to cylinders.
When this Air Pump is driven by some external
means like fan belt from crank pulley, it is called
SUPERCHARGER.
But when this Air Pump is driven by back pressure
of the exhaust gases, it is called TURBOCHARGER.
What is a turbocharger

101. Intake and exhaust
system

104. Wet type Air Cleaner

107. Dry type Air Cleaner

108. Muffler

109. Lubrication system
Functions:
 Reduce friction between moving part
 Absorb and dissipate heat
 Seal the piston rings and cylinder walls
 Clean and flushes moving part
 Help deaden noise of engine

110. Types of lubrication system
Types:
 Splash lubrication system
 Force feed lubrication system
 Combination of both

111. Circulating Splash System

112. Force feed lubrication
system

113. What is Viscosity ?
High Viscosity
Low Viscosity
Viscosity = Resistance to Flow

114. Viscosity
Viscosity varies as the fluid temperature changes
High temperature low viscosity
Low temperature high viscosity
Low High
Temperature

115. Viscosity Classification
SAE “W” (W means Winter)
viscosity measurements are
conducted at cold temperatures.
0W 5W 10W 15W 20W
thinner thicker
SAE 10W Range

116. thinner thicker
20 30 40 50 60
SAE 40 Range
Viscosity Classification
SAE high temperature viscosity measurements
are conducted at 100 ºC, the approximate
engine operating temperature.

117. Traditional monogrades
SAE 10W
SAE 20W
Low viscosity
for winter (thin)
SAE 30
SAE 40
SAE 50
High viscosity for
summer (thick)
Had to change the oil twice a year !

118. Multigrade oils
An oil whose flow characteristics are
defined at both high and low
temperatures.
SAE 10W – 30
Low Temperature High Temperature

120. Mechanical
Mechanical designs
employ an element made
of pleated filter media to
entrap and sequester
suspended contaminants.
As material builds up on
the filtration media, oil flow
is progressively restricted.
This requires periodic
replacement of the filter
element (or the entire
filter, if the element is not
separately replaceable).
Types of oil filter
FULL FLOW – SPIN ON type engine
oil filter with inbuilt Oil filter – by
pass Valves

121. Engine Oil Filter
In MDI & Arjun, filter is
mounted vertically as
shown .
In 235DI filter is mounted horizontally.
Hence filter construction of 235DI is
different compared to others.

122. 005556868 R91
MDI engine except
595 DI & 295 DI.
NEF engine
000020316 E05

123. 006001547B91
595 DI & 295 DI.
006000789 B91
235 & 245 engine

124. Cooling system
Functions:
 Prevent overheating and
 Regulate the temperature

125. Running the engine to hot can
cause
 Pre-ignition
 Detonation
 Knock
 Burn – piston and valves
 Lubrication filature

126. Running the engine to cold can
cause
 Unnecessary wear
 Poor fuel economy
 Accumulation of water -Sludge in the crank
case

127. Types of cooling system
 Air cooling system
 Liquid cooling system

128. Part of Liquid cooling system
 Radiator and pressure
cap
 Fan and fan belt
 Water pump
 Engine water jackets
 Thermostat valve
 Connecting hoses
 Liquid or coolant

129. Cooling system layout

130. Cold Engine
Pump Circulation System
When an engine is cold,
the thermostat is cold.
Coolant flow is through
the bypass hose and the
water jackets. This
allows the engine to
warm up evenly.

131. Warm Engine
 Pump Circulation System
The thermostat opens
when the engine warms
up. This allows coolant
to circulate through the
radiator and the water
jackets.

132. Engine
An engine is a device which transforms one form of
energy into other form.
An engine is a machine that produces mechanical
force and motion from another form of energy. The
chemical energy of fuel is first transferred to thermal
energy & then to mechanical energy.
It is also referred to as a prime mover.

134. Cooling system with
Recovery Bottle are known
as Closed Cooling system.
They are assigned to catch
& hold any coolant that
passes through the
pressure cap when the
engine is hot.
When the engine is shut
down, the coolant begins to
shrink. The vaccum spring
inside the Radiator Cap
opens & the coolant in the
Recovery Bottle is drawn
back into the cooling
system.
Recovery Bottle

135. The cooling system used on M & M Tractor is
pressurized & sealed by a radiator cap which
increase the boiling point of the coolant.
For every PSI (0.07 bar) increase, the boiling
point is raised by 1.8°C.
Ensure that proper Radiator cap is always used.
Radiator cap

136. Role of the Radiator Cap

137. 1. Water loss due to splashing.
Effect of not using proper Radiator cap
Do not remove Radiator cap when the
engine is HOT.
2. Water loss due to evaporation.
3. Closed cooling system will become Open
cooling system .

138. Thermostat Valve

139. Thermostat is a temperature – responsive coolant flow
control valve. It controls the temperature & amount of
coolant entering the radiator.
When the engine is cold, the thermostat remains closed &
allows the coolant to circulate only inside the engine thru
by pass circuit. This allows the engine to warm up quickly.
When the coolant reaches the opening temperature of the
thermostat, the thermostat begins to open & allows the
part of flow of coolant to radiator.
Thermostat Valve
The thermostat controls the minimum operating
temperature of the engine. The maximum operating
temperature is controlled by the amount of heat being
produced by the engine at that time & the cooling system’s
ability to dissipate the heat.

140. types of Thermostat Valve
By pass open type – as used in MDI engines.
Flow from By pass circuit continues even at thermostat
fully open condition.

141. types of Thermostat Valve
By pass closed type – as used in NEF engines.
Flow from By pass circuit completely stops at thermostat
fully open condition.

142. Governing system
 Maintain a selected speed
 Limit the slow and fast speed
 Shut down the engine when if over speed

144. Questions?