16802 engine cooling system
Post on 12-Sep-2014
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DESCRIPTION
TRANSCRIPT
ENGINE COOLING SYSTEM
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
Types of Cooling Air cooling Liquid cooling
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
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)
How it Works:
Liquid Cooled Systems - A pressurized closed circulation systemLiquid Cooled Systems - A pressurized closed circulation system
Parts of a Liquid Cooling System
Radiator & Pressure Cap
Fan & Belt Coolant Pump Water Jackets Thermostat Hoses Coolant
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
Water jackets
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
Water Pump
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
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
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.
Transmission oil coolers
Thermostat Thermostatic device Wax pellet 85 to 90°c It is placed at passage from cylinder
head to upper tank of radiator
Radiator Pressure cap Sealing and pressurizing
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)
Temperature indicator Balancing coil gauge Bimetallic thermostat gauge Indicator light