ENGINE ENGINE COOLINGCOOLING

NEED FOR COOLINGNEED FOR COOLING

ONLY ABOUT 20% OF HEAT IS USED ONLY ABOUT 20% OF HEAT IS USED AS POWER AT CRANK SHAFTAS POWER AT CRANK SHAFT

35% OF HEAT IS TRASMITTED TO 35% OF HEAT IS TRASMITTED TO THE CYLINDER WALLS WHICH THE CYLINDER WALLS WHICH CONSTITUTES POWER LOSSCONSTITUTES POWER LOSS

THE HEAT SHOULD BE PREVENTED THE HEAT SHOULD BE PREVENTED FROM BEING TRANSFERRED TO FROM BEING TRANSFERRED TO CYLINDER WALLS AS IT CAUSES CYLINDER WALLS AS IT CAUSES PREIGNITION OF CHARGEPREIGNITION OF CHARGE

LUBRICANT MIGHT ALSO BE BURNED LUBRICANT MIGHT ALSO BE BURNED BECAUSE OF EXCESSIVE HEATBECAUSE OF EXCESSIVE HEAT

THE BURNING OF LUBRICANT LEAD TO THE BURNING OF LUBRICANT LEAD TO SEIZURE OF THE PISTONSEIZURE OF THE PISTON

WHILE ENGINE IS RUNNING HEAT WHILE ENGINE IS RUNNING HEAT MUST BE REMOVED CONTINOUSLY MUST BE REMOVED CONTINOUSLY FROM THE ENGINEFROM THE ENGINE

TYPES OF COOLINGTYPES OF COOLING

DIRECT COOLING OR COOLING DIRECT COOLING OR COOLING BY AIRBY AIR

INDIRECT COOLING OR LIQUID INDIRECT COOLING OR LIQUID COOLINGCOOLING

AIR COOLINGAIR COOLING Air coolingAir cooling is a method of dissipating is a method of dissipating

heat

It works by making the object to be It works by making the object to be cooled have a larger surface area or have cooled have a larger surface area or have an increased flow of air over its surface, an increased flow of air over its surface, or both.or both.

An example of the former is to add An example of the former is to add fins to to the surface of the object, either by making the surface of the object, either by making them integral or by attaching them tightly to them integral or by attaching them tightly to the object's surface (to ensure efficient heat the object's surface (to ensure efficient heat transfer). transfer).

In the case of the latter it is done by using a In the case of the latter it is done by using a fan blowing blowing air into or onto the object one into or onto the object one wants to cool. wants to cool.

In many cases the addition of fins adds to the In many cases the addition of fins adds to the total surface area making a total surface area making a heatsink that makes that makes for greater efficiency in cooling. for greater efficiency in cooling.

In all cases, the air has to be cooler than the In all cases, the air has to be cooler than the object or surface from which it is expected to object or surface from which it is expected to remove heat. remove heat.

ADVANTAGES ADVANTAGES NO NEED OF RADIATOR COOLANT NO NEED OF RADIATOR COOLANT

AND WATER PUMPAND WATER PUMP LESS WEIGHT AND LOW COSTLESS WEIGHT AND LOW COST IN DESERTS AIR COOLING IS THE IN DESERTS AIR COOLING IS THE

PREFFERABLE METHODPREFFERABLE METHOD IN COLD COUNTRIES AIR COOLING IS IN COLD COUNTRIES AIR COOLING IS

UTILIZED FOR THE VEHICLES AS UTILIZED FOR THE VEHICLES AS WATER FREEZES INSIDE THE SYSTEMWATER FREEZES INSIDE THE SYSTEM

DISADVANTAGESDISADVANTAGES The cooling tends to be uneven and leads to The cooling tends to be uneven and leads to

cylinder distortion. Even though this has been cylinder distortion. Even though this has been remedied by placing the fins in a different remedied by placing the fins in a different manner, it is a problem nonetheless.manner, it is a problem nonetheless.

It is almost impossible to manage with air-It is almost impossible to manage with air-cooling if the number of cylinders increases cooling if the number of cylinders increases beyond two. beyond two.

The fins vibrate sometimes leading to a The fins vibrate sometimes leading to a lot of noiselot of noise

LIQUID COOLINGLIQUID COOLING IN WATER COOLING SYSTEMS, IN WATER COOLING SYSTEMS,

WATER JACKETS ARE PROVIDED IN WATER JACKETS ARE PROVIDED IN THE CYLINDER BLOCK AND THE THE CYLINDER BLOCK AND THE CYLINDER HEAD.CYLINDER HEAD.

WATER FILLS UP THESE JACKETS WATER FILLS UP THESE JACKETS AND THE HEAT IS TRANSFERRED TO AND THE HEAT IS TRANSFERRED TO THE WATER IN THE WATER JACKETS THE WATER IN THE WATER JACKETS THUS COOLING THE CYLINDERTHUS COOLING THE CYLINDER

TYPES OF LIQUID TYPES OF LIQUID COOLING SYSTEMSCOOLING SYSTEMS

THERMOSIPHON SYSTEMTHERMOSIPHON SYSTEM

PUMP COOLINGPUMP COOLING

THERMOSIPHON SYSTEMTHERMOSIPHON SYSTEM

ThermosiphonThermosiphon refers to a method of passive heat refers to a method of passive heat exchange based on natural convection which exchange based on natural convection which circulates liquid without the necessity of a circulates liquid without the necessity of a mechanical pump.mechanical pump.

Its intended purpose is to simplify the pumping of Its intended purpose is to simplify the pumping of liquid and/or heat transfer ,by avoiding the cost and liquid and/or heat transfer ,by avoiding the cost and complexity of a conventional liquid pumpcomplexity of a conventional liquid pump

PUMP COOLING SYSTEMPUMP COOLING SYSTEM A water pump is an important part of the engine A water pump is an important part of the engine

cooling system. It provides circulation of the engine cooling system. It provides circulation of the engine coolant (antifreeze) through the cooling system.coolant (antifreeze) through the cooling system.

A water pump pushes the coolant through the A water pump pushes the coolant through the passages (water jackets) in the engine cylinder passages (water jackets) in the engine cylinder block and cylinder head and then out into the block and cylinder head and then out into the radiator.radiator.

This helps to keep the engine from overheating; the This helps to keep the engine from overheating; the hot coolant passes through the radiator where it hot coolant passes through the radiator where it cools down and then returns back to the engine. cools down and then returns back to the engine.

Water pump problemsWater pump problems

Typical water pump problems include Typical water pump problems include coolant leaks, noisy or defective bearing, coolant leaks, noisy or defective bearing, damaged or corroded impeller.damaged or corroded impeller.

Faulty water pump might cause the Faulty water pump might cause the engine to overheat, which can result in engine to overheat, which can result in serious engine damage. If defective, a serious engine damage. If defective, a water pump is replaced as a unit. water pump is replaced as a unit.

THERMOSTATTHERMOSTAT Any liquid-cooled car engine has a small Any liquid-cooled car engine has a small

device called the device called the thermostatthermostat that sits between that sits between the engine and the radiatorthe engine and the radiator

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

When the engine is cold, no coolant flows When the engine is cold, no coolant flows through the engine. Once the engine reaches through the engine. Once the engine reaches its operating temperature (generally about 95 its operating temperature (generally about 95 degrees C), the thermostat opens. degrees C), the thermostat opens.

By letting the engine warm up as quickly as By letting the engine warm up as quickly as possible, the thermostat reduces engine wear, possible, the thermostat reduces engine wear, deposits and emissions. deposits and emissions.

RADIATORRADIATOR A radiator is a type of A radiator is a type of heat exchangerheat exchanger. . It is designed to transfer heat from the hot It is designed to transfer heat from the hot

coolant that flows through it to the air blown coolant that flows through it to the air blown through it by the fan. through it by the fan.

These radiators are made by brazing thin These radiators are made by brazing thin aluminum fins to flattened aluminum tubes.aluminum fins to flattened aluminum tubes.

The coolant flows from the inlet to the outlet The coolant flows from the inlet to the outlet through many tubes mounted in a parallel through many tubes mounted in a parallel arrangement. The fins conduct the heat from the arrangement. The fins conduct the heat from the tubes and transfer it to the air flowing through tubes and transfer it to the air flowing through the radiator. the radiator.

RADIATOR CAPRADIATOR CAP It keeps the cooling system sealed from It keeps the cooling system sealed from

outside contaminants.outside contaminants.

By keeping pressure on the cooling By keeping pressure on the cooling system, it raises the boiling pointsystem, it raises the boiling point ..

It contains pressure valve and the vaccum It contains pressure valve and the vaccum valve.valve.

ANTI FREEZE SOLUTIONANTI FREEZE SOLUTION A fluid, such as methanol or ethylene glycol, A fluid, such as methanol or ethylene glycol,

which is added to vehicle engine coolant or which is added to vehicle engine coolant or used in solar heating system heat transfer used in solar heating system heat transfer fluids, to protect the system from freezing.fluids, to protect the system from freezing.

The expansion of water exerts high pressure The expansion of water exerts high pressure inside the cooling system and causes serious inside the cooling system and causes serious damage to the pipe in the cooling systemdamage to the pipe in the cooling system

SCALES AND CORROSIONSCALES AND CORROSION ScaleScale formation and formation and corrosioncorrosion or rust are the or rust are the

most common problems encountered in the most common problems encountered in the cooling systems of engines cooling systems of engines

The composition of the water used for cooling The composition of the water used for cooling leads to scale formationleads to scale formation

The impurities present in water combine with The impurities present in water combine with air sucked into the cooling systemthrough the air sucked into the cooling systemthrough the water pump to produce rust.water pump to produce rust.

CORROSION AND SCALE CORROSION AND SCALE PREVENTIONPREVENTION

A special rust inhibitor is addedwith water in A special rust inhibitor is addedwith water in the cooling system to prevent the formation of the cooling system to prevent the formation of rust.rust.

Alkalies and acids are added to prevent scale Alkalies and acids are added to prevent scale formation.formation.

Kerosene and alkalies like washing soda Kerosene and alkalies like washing soda reduce oil or grease in the cooling system.reduce oil or grease in the cooling system.

THANK YOUTHANK YOU