Cooling system
The movement of the coolant and the removal of heat from the coolant require a system called the cooling system..The only purpose of of the engine’s cooling system is to remove excess heat from the engine, to keep the engine operating temperature at its most efficient level, and to get the engine up to the correct temperature as soon asa possible after starting.
A cooling sysytem is also required to prevent the internal engine parts from melting from the heat of the burning fuel.There are two types of the cooling system found on cars: liquid-cooled and air-cooled.
Air cooling
Some older cars, and very few modern cars, air-cooled.Instead of circulating fluid through the engine, the engine block is covered in aluminum fins that conduct the heat away from the cylinder.A powerful fan forces air over these fins, which cools the engine by treansferring the heat to the air.
Liquid cooling
The cooling system on liquid-cooled cars circulates a fluid through pipes and passageways in the engine. As this liquid passes through the hot engine it absorbs heat, cooling the engine. After the fluid leaves the engine, it passes through a heat exchanger, or radiator, which transfers the heat from the fluid to the air blowing through the exchanger.Most auomotive enginestoday are liquid cooled.
This system is made uo of a number of parts: the coolant pump, radiator, radiator hoses, radiator pressure cap, coolant recovery system, thermostat, fan, and drive belts.
Coolant and Coolant Pump
Most cars use a liquid cooling system that circulates liquid around hot engine parts to carry off the heat. The liquit is called a coolant,Cooling system now use a mixture of ethylene glycol and water.Ethlene glycol has long been used as antifreeze, which is a solution that prevents the cooling system liquid from freezing.If the coolant freezes If the coolant freezes in the radiator and the engine block, expanding ice could cause severe damage. Depending on the percetage of ethylene glycol used, the system can be protacted from freezing in temperatures well below zero.
When the liquid in a cooling system boils, the coolant turns to steam.When this happens, coolant circulation is stopped, and the engine and the engine temperature gets dangerously high.An advantage of ethylene glycol is that it has a boiling temperature far above the water.A half-and-half mixture of coolant and water has a boiling temperature of approximately 109℃.
The coolant pump, commonly called the water pump, circulats the coolant through the engine and into a heat exchanger.The pump is usually located on the front of the engine.Coolant passages in the engine are connected to the pump. A drive belt from a crankshaft pulley is connected to the coolant pump.When the engine is running, the crankshaft turns the drive belt. The hot coolant is pumped out of the engine and through a heat exchanger, that is, a radiator.
Radiator
The radiator is mounted in front of the engine comparment just behind the grill. Air in front of the car is directed into the radiator.The job of radiator is to transfer the heat to the outside air. Atypical radiator consists of two tanks and a center core. The coolant pump circulates hot coolant out of the engine block and through a large radiator hose into the right side tank. The hot coolant then flows across the core of the radiator through long, narrow tubes. These tubes are made from aluminum or copper for good heat transfer.
The radiator presssure cap fits on the top of the radiator. It can be removed to fill the radiator with coolant.The radiator cap has two other important jobs. The radiator cap controls the pressure and vacuum in the cooling system.
Thermostat
A thermostat is needed in an automobile cooling system to regulate the flow of heat.Most thermostat work by opening or closing a valve to control the flow of coolant. thermostat is usually mounted in a housing in the forward part of the intake manifold, or cylinder head, under the manifold outlet. Thermostat are designed to open and close at predetermined temperatures to maintain efficient engine opreating temperatures.The closed thermostat. As soon as the coolant heats up, the thermostat opens and allows coolant to flow to the radiator.
auther:candy.www.sinodiesel.com
