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1. COOLING SYSTEM
Yo u c a n f i n d m e a t
ka u s h a l g a d a r i y a @ g m a i l . c o m

2. CONTENTS
▶ Introduction
▶ Effects of high temperature in the engine
▶ Purpose of cooling
▶ Types of cooling system
▶ Air cooling system & its components (merits & Demerits)
▶ Liquid cooling system & its components (merits &
Demerits)
▶ Coolant/Anti-freeze

3. COOLING SYSTEM
▶ An automobile's cooling system is the collection of parts
and substances (coolants) that work together to maintain
the engine's temperature at optimal levels.
▶ Comprising many different components such as water pump,
coolant, a thermostat etc.
▶ The system enables smooth and efficient functioning of the
engine at the same time protecting it from damage
▶ The temperature produced on the power stroke of an
engine can be as high as 1600 degree and this is greater
than melting point of engine parts.

4. TRANSFORMATION OF FUEL ENERGY
35%
Exhaust
&
Cooling
35 %
Heat Dissipation
25-30 %
Mechanica
l
Work
4

5. Effects of high temperature in
the engine
▶ Due to high temperature, the piston would seized in
cylinder and stop the engine.
▶ Lubricating quality of the oil inside the cylinder would be
destroyed.
▶ Preignition of fuel mixture which cause engine knocking as
well as loss of power.

6. PURPOSE OF COOLING
▶ To maintain optimum temperature of an engine for
efficient operation under all conditions.
▶ To dissipate surplus heat for protection of engine
components like cylinder, cylinder head, piston, piston
ring and valves.
▶ To maintain the lubricating property of the oil inside the
engine cylinder for normal functioning of the engine.

7. TYPES OF COOLING
▶ In order to cool the engine a cooling medium is required.
On the basis of medium ,in general use for cooling I.C.
engine ,types of cooling system are:-
▶Air cooling system
▶Liquid or water cooling system

8. AIR COOLING SYSTEM

9. AIR COOLING SYSTEM
▶ Air cooled engines are those engines, in which heat is
conducted from the working components of the engine to
the atmosphere directly.
▶ The cylinder of an air cooled engine has fins to increase
the area of contact of air for speedy cooling.
▶ The amount of heat dissipated to air depends upon :
▶Amount of air flowing through the fins.
▶Fin surface area.
▶Thermal conductivity of metal used for fins.

10. COOLING FINS

11. MERITS & DEMERITS OF AIR
COOLING SYSTEM
▶ MERITS:
▶ It is more simple in design and construction
thermostat,
▶ Water jackets, radiators, water pumps,
pipes, hoses etc. are not needed
▶ It is more compact
▶ It is comparatively lighter in weight
▶ DEMERITS:
▶ There is uneven cooling of engine parts
▶ Engine temperature is generally high during working
period

12. LIQUID COOLING SYSTEM

13. LIQUID COOLING SYSTEM
▶ A liquid is circulated around the
cylinders and absorb heat from the
cylinder walls and cylinder head.
▶ Coolant absorbs heat as it passes
through the engine and also
lubricates the water pump.
▶ Hot coolant enters the radiator in
which the heat is passed on to air
that is flowing through the
radiator.

14. Working principle of water-
cooled system.

15. MERITS AND DEMERITS OF LIQUID
COOLING SYSTEM
▶ MERITS:
▶ Uniform cooling of cylinder, cylinder head and valves
▶ Specific fuel consumption of engine improves by using water cooling
system
▶ If we employ water cooling system, then engine need may not be
provided at the front end of moving vehicle.
▶ Engine is less noisy as compared with air cooled engines, as it has water
for damping noise
▶ DEMERITS:
▶ It depends upon the supply of water
▶ If the water cooling system fails then it will result in severe damage of
engine
▶ The water cooling system is costlier as it has more number of parts

16. TYPES OF WATER COOLED SYSTEM
Open Jacket
System
Thermo syphon
Cooling System
Forced
Circulation
Cooling System

17. OPEN JACKET SYSTEM
This system is used where plenty of water is available.
The water is supplied from large tank or river through
the inlet valve of cooling water jacket.
The main specification of this system is that Hot water
is not cooled but simply discharged.

18. THERMOSYPHON COOLING SYSTEM
 The basic principle of this system is based upon the
relative density of the water.
 The main advantage of this system is it’s simplicity and
automatic circulation of cooling water.

19. FORCED CIRCULATION SYSTEM
▶ This system is used in large number of automobiles like
Cars, tractor and even Heavy Trucks.
▶ Here flow of water from radiator to the water jackets is
assisted by pump.

20. • To supply the water forcely into the system
WATER PUMP
• To dissipates the heat from coolant
RADIATOR
• To provide strong draft of air through the radiator
F
AN
• Designed to keep engine block and cylinder head
cool.
WATER JACKETS
• T
o control the flow of coolant, it opens at 70
degree and fully open at 82 degree
THERMOSTAT VALVE
• To store the coolant
STORAGE TANK
COMPONENTS OF LIQUID COOLING
SYSTEM

21. RADIATOR
 Radiators
exchangers
transfer
are
used
heat
to
thermal
energy from one medium
to another for the purpose
of cooling and heating.
21

23. THERMOSTAT
VALVE
 Its job is to block the
flow of coolant to the
radiator until the engine
has warmed up.

24. Thermostat Closed Thermostat Open
When engine is cold When engine reaches the
specified temperature

25. WATER JACKETS
water jackets are
the
▶ Cooling
provided
cylinder,
around
cylinder head,
valve
part
seats,
which
and any hot
are to be
cooled. Heat generated in
the cylinder is conducted to
the Jacket.

26. ANTIFREEZE MIXTURE
▶ To prevent the freezing of cooling water in western
countries antifreeze mixture are added to the cooling
water
▶ There are the following type of antifreeze mixtures :-
▶Ethylene glycol
▶Propylene glycol
▶Organic acid technology (OAT)
▶Hybrid organic acid technology (HOAT)

27. Coolant/Anti-freeze
▶ Engine coolant is a mixture of water and
antifreeze/coolant.
▶ Water alone has a boiling point of 100°C and a freezing
point of 0°C at sea level.
▶ Engine coolant has a higher boiling temperature and a
lower freezing point than water.
▶ The exact boiling or freezing temperatures depend on
the mixture.
▶ The typical recommended mixture is a 50/50 solution of
water and antifreeze/coolant.