Unit 3:IC Engine

Dr. Jitendra Kumar Katiyar

POWER GENERATION
❖External Combustion Engines
❖Internal Combustion Engines
❖Power Plants

2
EXTERNAL COMBUSTION ENGINES
❖An external combustion engine (EC engine) is a heat engine
where an (internal) working fluid is heated by combustion in an
external source, through the engine wall or a heat exchanger.
❖The fluid then, by expanding and acting on the mechanism of
the engine, produces motion and usable work.
❖In this type of engine the of fuel takes
combustion outside the cylinder. place
❖These types of engines are used to
locomotives, ships Steam Engine, Steam Turbine, Closed cycle
gas turbine etc.
❖In locomotive steam is produced by the combustion of fuel and
this steam is used to move a piston in a cylinder.

3
4
 Internal Combustion
Engine
Function - Converts potential
chemical energy in fuel into heat
energy then to mechanical energy
to perform useful work.
Gasoline Engine, Diesel Engine,
Wankel Engine, Open cycle
Gas
Turbine
Chemical
Heat

Mechanical
INTERNAL COMBUSTION ENGINES
❖The internal combustion engine is an
engine in which the combustion of a fuel
(normally a fossil fuel) occurs with an oxidizer
(usually air) in a combustion chamber.
❖In an internal combustion engine the
expansion of the high-temperature and -pressure
gases produced by combustion applies direct
force to some component of the engine, such as
pistons, turbine blades, or a nozzle.
❖This force moves the component over a
distance, generating useful mechanical energy.

6
 Classification of IC Engines
Fuel used Type of cooling Operating speed
– Petrol – Air cooled – High
– Diesel – Water cooled – Medium
– Gas Type of lubrication – Low
Working cycle – Petroil (Mist) Application
– Otto cycle – Sump type – Automobile
– Diesel cycle Cylinder orientation – Marine
– Dual cycle – Horizontal – Power
Number of cylinders – Vertical generation
– Single cylinder Cylinder arrangement
– Multi cylinder – Inline / Radial
Type of ignition – V / W – type
– Spark ignition – X / H – type
– Compression – Opposed piston/
ignition cylinder
 COMPONENTS OF IC ENGINES
a) Crankshaft.
b) Exhaust camshaft.
c) Inlet camshaft.
d) Piston.
e) Connecting rod.
f) Spark plug.
g) Valves.
h) Cooling water jacket.
i) Valve Spring.
j) Piston pin.
k) Crank Case.
l) Cylinder Block.

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PISTON CONFIGURATIONS
Inline 6
Inline 4
Opposed
V-6
V-8
Connecting rod
Connects the piston to
the crankshaft
Converts reciprocating
piston motion to rotary
motion at the crankshaft.
Drop-forged steel
 Crankshaft

❖Works with connecting rod to change reciprocating

to rotary motion.
❖Transmits mechanical energy from the engine.
❖Made of heat-treated steel alloys.
Cylinder Bore
Diameter of the cylinder.

Crank Pin
Located at the end of the crank throw.
Holds the connecting rod bearing.

Dip Stick
For checking oil level.
 Internal Combustion Engine Terms
Top-dead center (TDC) –
• Position of the piston when it stops at the furthest
point away from the crankshaft.
• In some engines TDC is not at the top of the
engines.
• E.g . Horizontally opposed engines, radial engines
etc. We call this position Head End Dead Center
(HEDC).
• When the piston is at TDC, the volume in the
cylinder is a minimum called the clearance volume.
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• Bottom Dead Center (BDC):
• Position of the piston when it stops at the point closest
to the crankshaft.
• Some sources call this Crank End Dead Center
(CEDC) because it is not always at the bottom of
the engine.
• Some source call this point Bottom Center (BC).
• Stroke :
• Distance traveled by the piston from one extreme
position to the other : TDC to BDC or BDC to TDC.
• Swept volume/Displacement volume :
• Volume displaced by the piston as it travels
through one stroke.
• Compression ratio (r)
o The ratio of total volume to clearance volume of the
cylinder is the compression ratio of the engine.
o Typically compression ratio for SI engines varies form
8 to 12 and for CI engines it varies from 12 to 24.
V V1
r= max
= =
V V V2 v2
V min TDC
Displacement
BDC volume =
v1
V =V −V =V −V
disp BDC TDC 1 2
Mean Effective Pressure (MEP)
 Four stroke Spark Ignition (SI) Engine
Stroke 1: Fuel-air mixture introduced into cylinder
through intake valve 0.3 bar
Stroke 2: Fuel-air mixture compressed 8-13 bar
Stroke 3: Combustion (spark given ignition )
Stroke 4: Product gases pushed out of the cylinder through
A
FUEL the exhaust valve.
I Ignition
R

Fuel/Air
Combustion
Mixture Products

Intake Compression Power Exhaust

Stroke Stroke
Stroke Stroke 17
Animation of 4stroke engine
 Four strokes of CI Engine Cycle :
• Intake/Suction Stroke :
The same as the intake stroke in an SI engine with one
major difference : no fuel is added to the incoming
air.
• Compression Stroke :
⮚ The same as in an SI engine except that only air is
compressed and compression is to higher pressures and
temperature.
⮚ Late in the compression stroke fuel is injected directly into
the combustion chamber, where it mixes with very hot
air.
⮚ This causes the fuel to ignite, causing combustion to start.
• Combustion is fully developed by TDC and
continues at about constant pressure until fuel
injection is complete and the piston has
started towards BDC.
• Expansion/Power stroke :
• The power stroke continues as combustion
ends and the piston travels towards BDC.
• Exhaust blowdown same as with an SI engine.
• Exhaust stroke : Same as with an SI engine.
2 stroke engine
❖It's called a two-stroke engine because
there is a compression stroke and then a
combustion stroke.
❖Completes a power cycle in only one crankshaft
revolution and with two strokes, or up and down
movements, of the piston.
❖Intake and exhaust valve are replaced by ports
(opening) in the cylinder wall.
Operation of Two-
stroke
 4 stroke 2 stroke
One stroke is obtained in two One stroke is obtained in each
revolution of crankshaft. revolution of crankshaft.
Valves are provided. Ports are provided.
Engine is cooled by water. Cooled by air.
More space is required. Less space required.
Heavier flywheel required. Lighter flywheel required.
Thermal efficiency is more. Less.
Volumetric efficiency is high Less.
Less fuel consumption. More fuel consumption.
Required more lubrication. Required less lubrication.
Heavier engine: car, bus, truck Scooter, moped etc.
Valve actuating is required. Valve actuating mechanism is absent.
Costlier for same output. Cheaper for same output.
A flywheel is a mechanical device specifically designed
to use the conservation of angular momentum so as to
efficiently store rotational energy; a form of kinetic
energy proportional to the product of its moment of
inertia and the square of its rotational speed.
Trevithick's 1802 steam locomotive used a flywheel to
evenly distribute the power of its single cylinder.
FACTOR SI ENGINE CI ENGINE
INTAKE CONDITION AIR AND FUEL AIR ONLY
SPEED CONTROL THROTTLE A/F MIXTURE UNTHROTTLE FUEL
CONTROL
MIXTURE UNFORMITY NEARLY HOMOGENOUS HETERGENEOUS

EQUIVALENCE RATIO 0.85-1.25 0-0.7

EXHAUST TEMPERATURE HIGHER LOWER

COMPRESSION RATIO 7 TO 10 14 TO 20

REQUIRED STRENGTH LOWER HIGHER

CYCLE USED OTTO CYCLE DIESEL CYCLE

FUEL PETROL DIESEL
EFFICIENCY HIGH LOWER
SPARK PLUG PRESENT ABSENT
 ALTERNATE FUEL USED
FUEL USED
Petroleum : Biofuel &
Gasoline
Diesel vegetable oil
LPG
CNG Biofuel
Jet fuel
Hydrogen Biobutanol
Biodiesel
Bioethanol
Biomethanol
Biogas
Vegetable oil like
jatropha
 Calorific value of fuel
The heat liberated by combustion of a fuel is known as calorific
value or heat value of the fuel. It is expressed in kcal/kg of the fuel

Sl. No Name of fuel Calorific value, kcal/kg

1 Light Diesel Oil (L.D.O) 10300

2 High speed diesel oil (HSD) 10550

3 Power kerosene 10850

4 Petrol 11100
 Engine Pollution

The major pollutants

from the engines
includes
Carbon monoxide
Hydrocarbons
Oxides of Nitrogen
Particulates
IC ENGINES
DIFFERENT SYSEMS
• Fuel supply system
• Lubrication system
• Cooling system
• Ignition system
Fuel supply system
The fuel passes through a number of stages
before reaching the combustion chamber.
It includes the filtration and atomization of
fuel into fine particles.
It is necessary to atomize the fuel before
entering into the combustion chamber so that
complete combustion of fuel can take place.
Two types of fuel supply systems
Fuel supply system of spark ignition engine
Fuel supply system of compression ignited engine
Fuel Supply System Of SI Engine
In petrol engine the combustible mixture of fuel is prepared
outside the combustion chamber.
Proper air-fuel ratio is maintained with the help of a device
known as carburetor and this mixture is inducted into the
combustion chamber.
The air fuel ratio depends upon the various conditions. The
engine needs a richer mixture while starting and leaner
mixture at normal running conditions.
Such conditions must be fulfilled before entering the
combustion chamber.
The fuel from the tank is delivered to the float chamber
attached to the carburetor with the help of fuel pump.
The fuel pump maintains the constant pressure. In
carburetor fuel is mixed with air in required proportion.
After that the mixture of fuel and air is inducted into the
combustion chamber.
Fuel Supply System Of CI Engine
•In diesel engine only air is injected
during the suction stroke and it is
compressed during compression stroke.
•Fuel is injected into the combustion
chamber in the form of fine spray at the
end of compression stroke.
•A fuel injection system in a diesel
engine has to satisfy the following
requirements:
1. To inject the fuel at the right time in the cycle.
2. The fuel should be properly atomized.
3. The correct quantity of fuel should be injected depending upon the load.
Fuel pump takes the fuel from fuel tank
and delivers it to the fuel filter.
When the pressure is developed in the
injection pump the fuel flows from
injection pump to the fuel injector
under pressure.
The fuel injector is either a single hole
nozzle or multi-hole nozzle.
Cooling Systems
 Reasons for Cooling
❖to promote a high volumetric efficiency
❖to ensure proper combustion, and
❖to ensure mechanical operation & reliability.

Effect of Over-cooling
Thermal efficiency is decreased due to the
more loss of heat carried by the coolant
❖the vaporization of the fuel is less
resulting in lower combustion efficiency
❖low temperature increases the viscosity of
lubricant causing more loss due to friction.
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2
Types of Cooling System

❖ Air cooling (or direct cooling) system

❖ Liquid cooling (or indirect cooling)
system

Remark: Aviation engines, cycle

motor while the stationery and
engines
automobile engines are liquid cooled.

and scooter engines are

Air cooled;

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3
 Air cooling system
❑Air cooled engines depend on airflow
across their external surfaces of the engine
cylinders to remove the necessary heat. The
amount of heat dissipated depends upon:

❖the area of cooling

surface in contact with the air
❖ mass flow rate of air
❖temperature difference
between cylinder and air and
❖ conductivity of metal.

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4
 Cooling fins in air cooled system
❑The area of cooling surface is increased by
forming thin fins, either integrally by machining
them on the outer walls of the engine cylinder
and cylinder head or by attaching separate fins
to them.

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5
 Air cooling system - Advantages

❖The absence of radiator, cooling

jackets, coolant and pumps make
the cooled engine is an advantage.

❖ Handling of liquid coolant requires

climate where liquid may freeze.

❖ In places where water is scarce, air engine
lighter.
❖ The engine can be operated in
cold piping and pumping auxiliaries.

❖Air cooled engines have no coolant

leakage or freezing problems. 4
6
 Air cooling system - Disadvantages

❖Relatively large amount of poweris

used to drive the cooling fan.
❖Engines give low poweroutput.
❖Cooling fins under certain
conditions may vibrate and amplify the noise
level.
❖ Cooling is not uniform.
❖Engines are subjected
working temperature. To high
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Liquid cooling systems -
Types
❖ Direct or non-return system
❖ Thermosyphon system
❖ Forced circulation cooling system
❖ Evaporative cooling system

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 Liquid
❖ Direct or non-return convectioncurrent
system Liquid stagnant film
Scale film
❑The heat released from Metal cylinder
wall Oil film
the combustion of air- Gas stagnant film
fuel mixture is transferred Gas convection
current Radiation
in all directions to the through gas

walls of the combustion

chambers, cylinders and
pistons convection Combustio
n of air-
Conductio

Liquid convection movement

n
currents of gas fuel
charge
Conductio
❑ by direct radiation, by n

rubbing against a Conductio

n
stationary gas film, then by
conduction
❑and through this stagnant
boundary layer of gas and
Heat Transfer through a
an oil film to the metal liquid cooled cylinder wall 10
wall.
Thermo-syphon system
❑ In this system, a fan
rotated by the crankshaft
Radiator
draws cold air from outside
through the radiator. The Cylinder

radiator is connected to the

engine block by means of
two pipes.
Piston
The hot water passes
through some thin pipes built
in the radiator, where it gets
cooled.
Thus, the fluid circulates
through the system in the
form of convective currents. Schematic diagram of a
thermosyphon system

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Forced circulation cooling system
❑This system is used in a large
number of vehicles like cars,
buses, trucks and other heavy
vehicles. Here, circulation of
water takes place with
convection currents helped by a
pump.
The water or coolant is circulated
through jackets around the parts
Of the engine to be cooled, and is
kept in By a centrifugal motion
pump, driven from the engine.
A thermostat is
used to control the water
temperature required for Schematic diagram of a
forced circulation system
cooing.
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Pump-cooling or forced cooling
• Pump is introduced between radiator and engine
block

• Rotated by crankshaft by means of a belt

• Water is circulated with force => heat is removed quickly

Limitation
Cooling is independent of temp. =>Engine is overcooled
(range of temp.=75-900C)
Pump cooling system

Can be overcome
by using
thermostat.

1
3
Cooling fan

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 Liquid cooling system - Advantages
❖Because of even cooling of cylinder barrel
and head (due to jacketing) makes it
possible to reduce the cylinder head and
valve seat temperatures.
❖The volumetric efficiency of water cooled
engines is higher than that of air- cooled
engines.

❖Compact design of engines with

appreciably smaller frontal area is possible.
❖In case of water cooled engines,
installation is not necessarily at the front of
the mobile vehicles, aircraft etc. as the
cooing system can be conveniently located.
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 Liquid cooling system - Disadvantages

❖The system requires more maintenance.

❖The engine performance becomes
sensitive to climatic conditions.
❖The power absorbed by the pump is
considerable and affects the power
output of the engine.

❖In the event of failure of the cooling

system serious damage may be caused
to the engine.
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 Use of Anti-freezers
During winter or when the engine is kept out of
operation in cold places, the cooling water in the
cylinder jackets, radiator tanks and and lead pipes
will freeze, expand leading to their fracture.
To prevent damage to the engine and radiator
during winter weather, suitable liquids or
compound substances (known as anti-freezers)
which go into solution are added to the water to
lower the freezing temperature of the coolant.

❖Ethylene glycol is the most widely used

automotive cooling-system antifreeze,
although methanol, ethanol, isopropyl alcohol,
and propylene glycol are also used.
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Lubrication
Systems
 Purpose of Lubrication
❖Reduce the frictional resistance of the
engine to a minimum to ensure maximum
mechanical efficiency.
❖Protect the engine against wear.

❖Serve as a cooling agent by picking up

heat.

❖Remove all impurities from the

lubricated region.

❖Form a seal between piston rings and the

cylinder walls to prevent blowby.
Lubrication Systems
❖ Mist lubrication Two Stroke
system Engines
❖ Wet sump lubrication
system Four Stroke Engines
❖ Dry sump lubrication system

6
0
Mist lubrication system is mainly employed in
two- stroke cycle engines, whereas wet and dry
sump systems are used in four-stroke cycle
engines.
The wet sump system is employed in relatively
small engines, such as automobile engines,
while the dry sump system is used in large
stationary, marine and aircraft engines.
 Mist Lubrication Systems

❑In two-stroke engines, the charge is compressed in the

crankcase, and as such it is not suitable to have the lubricating oil
in the sump.
❑Therefore, such engines are lubricated by adding 3 % to 6 %
oil in the fuel tank itself. The oil and fuel mixture is inducted
through the carburetor. The fuel gets vaporized in the form of
mist goes into the cylinder through the crankcase walls
lubricates the crankcase.

❑The oil that impinges the main and connecting rod

bearings, and the rest of the oil lubricates the piston,
piston rings and cylinder.
❑The main advantage with this system lies in the simplicity
and low cost as the system does not require any oil pump,
filter etc.

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 Wet Sump Lubrication Systems

❑In the wet sump system, the bottom of the

crankcase contains an oil sump (or pan) that
serves as the oil supply reservoir.
❑Oil dripping from the cylinders and bearings
flows by gravity back into the wet sump
where it is picked up by a pump and re-
circulated through the engine lubricating
system. The types of wet sump systems used
are:

❖ the splash and circulating pump system

❖ the splash and pressure system
❖ the full force-feed system
Splash and Circulating Pump System

C a m s ha f t

C onnec t in g r o d
be a r i n g s
M a in be a r in g

m a in
bea rin g

Lo w e r O il
o il pan t rou ghs

O il pum p

O il S t r a i n e r
Splash and circulating pump
system
•This type of lubrication is generally used
in some small four-stroke engines.
•In its construction a cap is present on the
big end of the connecting rod which
consists of a scoop.
•When the connecting rod is at the lowest
position, the scoop gets dipped into the oil,
thus it directs the oil into the holes present
in the bearing.
 Splash and Pressure System

Camshaft

C onnec t in g r o d
be a r i n g s
M a in be a r in g

m a in be
a rin g

O il pum p

O il S t r a i n e r
6
5
Forced feed lubrication system
In this system oil is pumped from oil sump
and it is distributed to various parts
requiring lubrication. The oil
from the oil sump through a is filter and it is
drawn
pumped by means of gear pump. Here oil
is delivered at a pressure of 1.5 bar to 4 bar.

The oil with pressure is supplied to the

main bearing in the crankshaft and
Forced feed
syste
m
 Properties of Lubricating Oil

❖The oil used in an engine must serve as a

lubricant, a coolant and an agent for
removing impurities.

❖It must be able to withstand high

temperatures without breaking down. The
oil must operate over a good range of
temperature.

❖They must not oxidize on the chamber

walls, piston crown or at the piston rings.
Oil should have high film strength to
prevent metal-to-metal contact even under
extreme loads.
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Ignition Systems
What is Ignition System ???
⮚ The system in an internal-
combustion engine that produces the
spark to ignite the mixture of fuel and
air: includes the battery, ignition coil,
distributor, spark plugs, and
associated switches and wiring.
 IGNITION FUNCTION

⚫ Produces 30,000 volt spark across spark plug

⚫ Distributes high voltage spark to each spark plug
in correct sequence
⚫ Times the spark so it occurs as piston is nearing top
dead center
⚫ Varies spark timing with load, speed, and other
conditions
 BASIC IGNITION SYSTEM
COMPONENTS
⚫ BATTERY
⚫ IGNITION SWITCH
⚫ IGNITION COIL
⚫ SWITCHING DEVICE
⚫ SPARK PLUG
⚫ IGNITION SYSTEM WIRES
 BASIC IGNITION SYSTEM
⚫ Battery supplies power
to entire system
⚫ Ignition Switch
turns engine on or
off
⚫ Coil transforms volts
⚫ Switching device
triggers ignition coil
⚫ Spark Plug and
wires distribute
spark
 IGNITION
COIL
⚫ Transformer
⚫ 2 sets of windings
⚫ Primary windings
⚫ Secondary
windings
⚫ Iron core
⚫ Produces
magnetic field
IGNITION SYSTEM TYPES

✓ Battery ignition system

✓Magneto ignition system
✓Distributor less ignition system
 BATTERY IGNITION SYSTEM

⮚ A battery ignition system has a 6- or 12-volt battery

charged by an engine-driven generator to supply
electricity, an ignition coil to increase the voltage, a
device to interrupt current from the coil, a distributor
to direct current to the correct cylinder, and a spark
plug projecting into each cylinder.
⮚ Current goes from the battery through the primary
winding of the coil, through the interrupting device,
and back to the battery.
 The primary circuit consist of the battery, ammeter, ignition
switch, primary coil winding, capacitor, and breaker
points. The function of these components are :

⮚ Battery – Provides the power to run the system

⮚ Ignition switch – allows the driver to turn the system
on and off
⮚ Primary coil – produces the magnetic field to create
the high voltage in the secondary coil.
⮚ Breaker points – a mechanical switch that acts as
the triggering mechanism
⮚ Capacitor – protects the points from burning out.
 The Secondary circuit converts magnetic induction into high
voltage electricity to jump across the spark plug gap, firing
the mixture at the right time.

The function of the components are –

⮚ secondary coil – the part of the coil that creates the

high voltage electricity.
⮚ Rotor – spin around on the top of the distributor shaft,
and distributes the spark to the right spark plug.
⮚ spark plug – Take the electricity from the wires and give it
an air gap in the combustion chamber to jump across to
light the mixture.
MAGNETO IGNITION SYSTEM
⮚ The simplest form of spark ignition is that using a
magneto.
⮚ An ignition magneto, or high tension magneto, is
a magneto that provides current for the ignition system of
a spark-ignition engine, such as a petrol engine.
⮚ The engine spins a magnet inside a coil, or, in the earlier
designs, a coil inside a fixed magnet, and also operates a
contact breaker, interrupting the current and causing the
voltage to be increased sufficiently to jump a small gap.
⮚ The spark plugs are connected directly from
the magneto output.
 What is Magneto Ignition System?
Magneto ignition system is an ignition system in
which magneto is used [produces high voltage] for
the generation of electricity and further that
electricity is used in several things like to run the
vehicles.
This is basically used in two-wheeler vehicles (Spark
Ignition Engine) nowadays.
Parts of Magneto Ignition System:

The main parts of Magneto Ignition System are:

1. Transformer core
2. Contact Breaker
3. Cam
4. Capacitor
5. Ignition Switch
6. Distributor
7. Spark Plug
Working Principle of Magneto Ignition System:

• In the Magneto Ignition System, magneto is used.

• When the engine of the system starts, it helps the magneto to rotate
and thus it’s producing the energy in the form of high voltage then, one
end of the magneto is grounded through a contact breaker, and the
ignition capacitor is connected to its parallel.
• The contact breaker is regulated by the cam and when the breaker is
open, current flows through the capacitor and charges it.
• Now the capacitor is acting as a charger now, the primary current flow is
reduced, thus reducing the overall magnetic field, generated in the
system.
• This increases the voltage in the capacitor.
• This increased high voltage in the capacitor will act as an EMF thus
producing the spark, at the right spark plug through the distributor.
• And at the starting stage, the speed of the engine is low and hence the
voltage generated by the magneto is low.
• But as the rotating speed of the engine increases, it also increases the
voltage generated by the magneto thus the flow of the current is also
increased.
 Rotor
Magneto Unit
Arm
Spark
Generation

Condenser

Power
Generation

Coil
Distribution

Contact
Magneto
Breaker

Ignition
Switch

IGNITION SYSTEM – Magneto

System
 DISTRIBUTOR LESS IGNITION SYSTEM
Distributor less Ignition System (DIS) is the ignition system in which the distributor of the
electronic ignition system is replaced with the number of induction coils i.e. one coil per cylinder
or one coil for pair of cylinders, and the timing of the spark is controlled by an Ignition control unit
(ICU) and the Engine control unit (ECU), which makes this system more efficient and accurate.
1. Battery:
Same as the electronic ignition system, the battery is used as the
powerhouse for the DIS.

2. Ignition Switch:
It governs the ON and OFF of the ignition system, same as the electronic
ignition system.

3. Ignition coil and Ignition Control Module

In the Distributor less ignition system, a complete assembly of ignition
coils and module is used to make the system compact and less
complicated.
(i) Ignition Coils: Unlike the electronic ignition system in which a single ignition
coil is used to generate high voltage ,DIS uses a number of ignition coils i.e.
each coil per spark plug which generates high voltage individually for each spark
plug.
(ii) Ignition Control Module (ICM) or Ignition Control Unit: It is the
programmed instruction given to the chipset which is responsible for setting the
primary coil circuit to ON or OFF,
4. Magnetic Triggering Devices:
These are the devices used to control the timing of the spark plug by
sensing the position of the crankshaft and camshaft both, a magnetic
triggering device consists of triggering wheel having teeth along with a
sensor, two magnetic triggering devices are used in Distributorless ignition
system that are-
(i) Camshaft Triggering Device: Mounted on the camshaft and used for
sensing valve timing.
(ii) Crankshaft Triggering Device: Mounted on the crankshaft and used
for sensing the piston position or stroke.

5. Spark Plug:
It is used to generate spark inside the cylinder.
Advantages of Magneto Ignition System:

These are the following advantages of Magneto Ignition

System:

This system requires less maintenance as compared to the Battery

ignition system.
This is more useful because no battery is used.
It occupies less space.
An electric circuit is generated by the magneto
No battery is needed, so no problem of battery discharge
Efficiency improves due to high-intensity spark.
Disadvantages of Magneto Ignition System:

Although there are some disadvantages:

During starting, the quality of spark is poor due to low speed.

This is a little expensive as compared to another ignition system.

Applications of Magneto Ignition System:

• Magneto Ignition System nowadays widely used in:

• This system is used for the generation of electricity (In case of

Battery system their Battery is used) and to run the vehicles.

• This is basically used in two-wheeler vehicles (SI Engine)

nowadays.
• A rotating magnet produces high voltage.

• And also this is used in various places like: Tractors, Outboard

Motors, Washing Machines, Buses, Power Units, Marine
Engines, and Natural Gas Engines.
 Cap Connector

Ceramic
Body

Hexagon

Outer Casing

Copper Sealing

Gasket Securing
Gap
Thread
Outer
Electrode

IGNITION SYSTEM – Spark Plug

IC ENGINES NUMERICAL
PROBLEMS
FORMULAES USED
 Questionnaire :
• Question1 : In which stroke does the engine produce
power?
– Answer : The engine produces power in the
expansion stroke of the engine cycle.
• Question2 : What is spark ignition engine and
compression ignition engine ?
– Answer : Spark ignition engine requires external
spark to iginite fuel and air mixture for initiating
combustion.
– In Compression ignition engine the air fuel
mixture self ignities due to the high temperature
caused by high compression. 7
• Question3: Define valve overlap and when it occurs in
the engine cycle?
– Answer: The duration of crank angle in which both
inlet and exhaust valve remains open is called as
valve overlap.
– It occurs at the end of exhaust stroke when the
piston is about to reach TDC and continues for a
few degree of crank angle after TDC, refer valve
timing chart.
 References:
• 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.html
• http://www.kruse-ltc.com/Otto/otto_cycle.phphttp://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

8
 References:
• http://content.answers.com/main/content/img/BritannicaConcise/images/72180.jpg
• http://www.howcarswork.co.uk/modules/content/index.php?id=23http://
www.howcarswork.co.uk/modules/articles/index.php?cat_id=1

• Internal Combustion engine fundamentals John B. Heywood

• Engineering Fundamentals of the Internal combustion Engine.
Willard W. Pulkrabek