various types of cooling systems in ic engine

1. I.C ENGINES
COOLING SYSTEMS
BY
VISWAASWARAN. J
II YEAR MECHANICAL ENGINEERING
DR.NGP INSTITUTE OF TECHNOLOGY

2. COOLING SYSTEM
• A cooling system is the collection of parts and substances
that work together to maintain temperature at optimum
levels.
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3. WHY COOLING SYSTEM IS NECESSARY IN AN IC
ENGINE?
• Over heating of the parts will result in engine breakdown.
hence it must be cooled properly.
ILL EFFECTS OF OVERHEATING
• Evaporation of lubricating oil.
• Setting up of thermal stress.
• Sticking of piston rings to the grooves.
• Burning of piston crown.
• Burning and warping of exhaust valves. 11 February 2018 3

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5. HEAT DISTRIBUTION
• Cylinder
• Cylinder head
• Valves
• Spark plug(petrol engine)
• Fuel injector (Diesel engines)
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6. OPTIMUM COOLING
• To avoid the overheating as mentioned above, the engine must be cooled in
order to run properly but it should not be cooled over.
EFFECTS OF OVERCOOLING
• Reduction in thermal efficiency.
• Increased corrosion in engine parts.
• Improper vaporization of fuel.
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7. TYPES OF COOLING SYSTEMS
• The excessive heat carried away by the engine components is to be
conveyed finally to the atmosphere by the cooling system.
Two general methods are generally used:
• Air cooled system.
• Liquid cooled system
(a)Thermosyphon
(b)Evaporative cooling system
(c)Force circulation cooling system
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8. AIR COOLED SYSTEM
• The engine have metal fins on the outer perimeter of the
engine.
• Heat is transferred from fins to atmosphere.
HEAT DISSIPIATING CAPACITY DEPENDS ON THE
FOLLOWING:
1. Shape and size of the fins and spacing of the fins.
2. Velocity and amount of the air stream flowing over the
fins
3. Temperature of the cylinder , fins and the cooling air
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9. MERITS AND DEMERITS OF AIR COOLING
MERITS
• Engine weight is reduced.
• Cheaper to manufacture.
• Overall size is reduced.
• Quick starting is possible even in frosty weather.
DEMERITS
• Greater mechanical noise.
• Not suitable for multi-cylinder engine.
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10. LIQUID COOLED SYSTEM
• FORCED CIRCULATION COOLING SYSTEM.
• THERMOSYPHON.
• EVAPORATIVE COOLING.

11. COMPONENTS OF COOLING
SYSTEM
LIQUID COOLED

12. FORCED CIRCULATION COOLING SYSTEM
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13. FORCE ASSISTED COOLING SYSTEM
WATER JACKET
In an internal combustion engine the water jacket is a series of holes either cast or bored through the main engine block
and connected by inlet and outlet valves to a radiator.
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14. WATER PUMP
• Its purpose is to circulate coolant .
• It is driven by the belt attached to the crank shaft
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15. RADIATOR
• It is the major part of the cooling system. There is a fluid in the inner core of the radiator and it transfers
the heat to the cooling fins that effectively remove heat from the coolant.
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16. COOLING FANS
• Fan blades are made up of sheet metal 1.2 -1.6 mm thickness and are riveted to the hub.
• The maximum velocity of the centrifugal fans reaches 70-100m/sec.
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17. PRESSURE CAP
The radiator pressure cap is a simple device that will maintain pressure in the cooling system up to a
certain point. If the pressure builds up higher than the set pressure point, there is a spring loaded valve,
calibrated to the correct Pounds per Square Inch (psi), to release the pressure.
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18. THERMOSTAT
• Thermostat is the very effective part of the cooling system of an engine which controls the small
amount of operating temperature. If the vehicle engine is cold, the thermostat will close so the engine
can warm-up speedily. It will open when the temperature allows coolant to go through the radiator.
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19. BYPASS
This system helps coolant to pass through the engine and then bypass the
radiator and helps the temperature in balancing.
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22. PROBLEMS WITH LIQUID COOLING
• Cooling jackets should be free from aeration or bubbles.
• Distortion of coolant jacket.
• Formation of scales in jacket.
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23. THERMOSYPHON
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24. COOLANT OIL & ANTI-FREEZE OIL
• GLYCOL-WATER MIXTURE
The specific heat of water or water/glycol is about twice that of oil, so a given volume
of water may absorb more engine heat than can the same volume of oil. Therefore, water may
be a better coolant if an engine is permanently producing large amounts of heat, making it
better for high-performance or racing engines.
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