T-Bird
06-23-2006, 11:46 PM
Engine Cooling System
Automotive engines generate a large amount of heat. About one-third of the heat energy developed by the fuel burning in the cylinders is converted into power to drive the vehicle. Another third is wasted and goes out the exhaust. The remaining third is absorbed by the metal of the engine and must be disposed of by the cooling system to prevent overheating.
An Engine will be damaged if the operating temperature gets too high, above the coolant boiling point, 260* F (125*C). This damage can show as preignition and detonation, a warped or cracked cylinder head or block, or piston-to-cylinder-wall scuffing.
Most modern engines are Liquid cooled: Liquid coolant is used to transfer heat to the airstream. Many small gas engines and motorcycles are air cooled. Air is blown across fins attached to the cylinders and heads to remove excess heat.
A conventional cooling system consists of five major parts a Radiator, Radiator Cap, Thermostat, Water Jackets, and a Water Pump.
The radiator is a device that hot coolant/antifreeze runs through in small tubes and then air moves along the outsides across fins that absorb a majority of the heat. The radiator usually gets airflow across it with the help of a fan and fan shroud to help direct the air across it.
The radiator cap is more than just a cap to keep coolant from spilling out, it is designed as a pressure relief valve that when the heat is getting too high and pressure builds within the system the cap will open up and relieve the pressure. The Thermostat is a valve that controls the flow of coolant within the engine itself.
The thermostat is made with a wax substance that when heated to a certain temperature will allow it to open up and permit flow through the engine. The main purpose of the thermostat is to allow an engine to get to operating temperatures in a reasonable amount
of time.
Water jackets are machined/cast into the block to direct flow of the coolant through the engine in an efficient manner. The water jackets mainly surround the cylinder walls to absorb the maximum amount of heat quickly.
The Water Pump is a nonpositive displacement centrifugal pump. In most vehicles the water pump is driven by the accessory drive belt. In some High Performance applications, the pump is controlled by a separate electrical motor. There are some applications where the water pump is gear driven also.
Coolant is the working fluid that transfers heat in a cooling system, much like the refrigerant in an A/C system. Water is the base coolant because it is plentiful, in-expensive, flows easily, and has an excellent ability to absorb and release heat. Water has drawbacks, though: It freezes at too high a temperature, boils at too low a temperature, and can cause metal corrosion (rust on metal and oxide on aluminum). The chemicals in high-quality antifreeze improve water to make it an excellent coolant. These chemicals are designed to lower its freezing point, raise its boiling point, reduce cavitation, and prevent rust and corrosion.
Automotive engines generate a large amount of heat. About one-third of the heat energy developed by the fuel burning in the cylinders is converted into power to drive the vehicle. Another third is wasted and goes out the exhaust. The remaining third is absorbed by the metal of the engine and must be disposed of by the cooling system to prevent overheating.
An Engine will be damaged if the operating temperature gets too high, above the coolant boiling point, 260* F (125*C). This damage can show as preignition and detonation, a warped or cracked cylinder head or block, or piston-to-cylinder-wall scuffing.
Most modern engines are Liquid cooled: Liquid coolant is used to transfer heat to the airstream. Many small gas engines and motorcycles are air cooled. Air is blown across fins attached to the cylinders and heads to remove excess heat.
A conventional cooling system consists of five major parts a Radiator, Radiator Cap, Thermostat, Water Jackets, and a Water Pump.
The radiator is a device that hot coolant/antifreeze runs through in small tubes and then air moves along the outsides across fins that absorb a majority of the heat. The radiator usually gets airflow across it with the help of a fan and fan shroud to help direct the air across it.
The radiator cap is more than just a cap to keep coolant from spilling out, it is designed as a pressure relief valve that when the heat is getting too high and pressure builds within the system the cap will open up and relieve the pressure. The Thermostat is a valve that controls the flow of coolant within the engine itself.
The thermostat is made with a wax substance that when heated to a certain temperature will allow it to open up and permit flow through the engine. The main purpose of the thermostat is to allow an engine to get to operating temperatures in a reasonable amount
of time.
Water jackets are machined/cast into the block to direct flow of the coolant through the engine in an efficient manner. The water jackets mainly surround the cylinder walls to absorb the maximum amount of heat quickly.
The Water Pump is a nonpositive displacement centrifugal pump. In most vehicles the water pump is driven by the accessory drive belt. In some High Performance applications, the pump is controlled by a separate electrical motor. There are some applications where the water pump is gear driven also.
Coolant is the working fluid that transfers heat in a cooling system, much like the refrigerant in an A/C system. Water is the base coolant because it is plentiful, in-expensive, flows easily, and has an excellent ability to absorb and release heat. Water has drawbacks, though: It freezes at too high a temperature, boils at too low a temperature, and can cause metal corrosion (rust on metal and oxide on aluminum). The chemicals in high-quality antifreeze improve water to make it an excellent coolant. These chemicals are designed to lower its freezing point, raise its boiling point, reduce cavitation, and prevent rust and corrosion.