2. Purpose
Keep engine at its most efficient
temperature
In combustion process the temperature
of gases is 2200°c
Coming to walls of cylinder it is 180 -
260°c
This temperature should maintain
More heat should not absorb by cooling.
up to 35% of heat
4. Air cooled Engine
Metal fine are extended to cylinder walls
Engine exposed to air
Shrouds and fans are used in some
engines
Engines are open not grouped
5. Water Cooled Engines
Coolant circulate around cylinder walls
It takes the heat by convection process
Coefficient of heat transfer is higher in
liquids
Coolant is a mixture of water and
antifreeze. (Normally 40/60 mixture)
6. How it Works:
Liquid Cooled Systems - A pressurized closed circulation system
7. Parts of a Liquid Cooling System
Radiator & Pressure
Cap
Fan & Belt
Coolant Pump
Water Jackets
Thermostat
Hoses
Coolant
8. Water jackets
Open space between outside and inside
walls of cylinder
The coolant circulates freely around
engine hot spots
It includes valve seats and guides and
upper parts of cylinder where piston and
rings slides
10. Water pump
Impeller type centrifugal pumps
Placed at front end of cylinder block and
back to radiator
It can circulate 28,390 lit of coolant per
hour
It consist inlet, outlet, impeller, bearings
and seals
12. Engine Fan
To pull air through radiator
It improves cooling at slow speeds
Four to six blades, shrouds
Variable speed fan
Flexible blade fan
Electric fans
13.
14. Radiator
Heat exchanger device
It holds large volume coolant in close
contact with large amount of air
Cores and pipes
Inlet tank and sink
Down flow and cross flow
15.
16. Expansion tanks
Separate plastic reservoir
Recovery tank
Connected to over flow
Coolant in engine is expands…contrasts
Surge tank
An advantage to the use of an expansion
tank is that it eliminates almost all air
bubbles from the cooling system. Coolant
without bubbles absorbs heat better.
23. Anti Freeze Solutions
An antifreeze is a chemical additive which
lowers the freezing point of a water-based
liquid
Lowers galvanic corrosion
Maintain small viscosity to water
methanol (methyl alcohol)
propylene glycol
5% additives
sodium silicate, disodium phosphate, sodium
molybdate, sodium borate, and dextrin
dye (commonly a green, red, orange, yellow,
or blue fluorescent)