Heater Core - AbsoluteAstronomy.com

A heater core is a radiator

Radiator (engine cooling)

Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine....

-like device used in heating the cabin of a vehicle

Vehicle

A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....

. Hot coolant

Coolant

A coolant is a fluid which flows through a device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor...

from the vehicle's engine

Engine

An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

is passed through a winding tube of the core, a heat exchanger between coolant and cabin air. Fins attached to the core tubes serve to increase surface for heat transfer to air that is forced past them, by a fan, thereby heating the passenger compartment.

How it works

The internal combustion engine

Internal combustion engine

The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

in most car

Čar

Čar is a village in the municipality of Bujanovac, Serbia. According to the 2002 census, the town has a population of 296 people.-References:...

s and truck

Truck

A truck or lorry is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, with the smallest being mechanically similar to an automobile...

s is cooled by a water and antifreeze mixture that is circulated through the engine and radiator by a water pump

Water Pump

Water Pump is one of the neighbourhoods of Gulberg Town in Karachi, Sindh, Pakistan. It is near main Water Pump that supplies fresh water to the city of Karachi....

to enable the radiator

Radiator

Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...

to give off engine heat to the atmosphere. Some of that water can be diverted through the heater core to give some engine heat to the cabin.

A heater core is a small radiator

Radiator

, located under the dashboard

Dashboard

A dashboard is a control panel placed in front of the driver of an automobile, housing instrumentation and controls for operation of the vehicle....

of the vehicle and consists of conductive aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

or brass

Brass

Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...

tubing with cooling fins to increase surface area. Hot coolant passing through the heater core gives off heat before returning to the engine cooling circuit.

The fan

Fan (mechanical)

A mechanical fan is a machine used to create flow within a fluid, typically a gas such as air.A fan consists of a rotating arrangement of vanes or blades which act on the air. Usually, it is contained within some form of housing or case. This may direct the airflow or increase safety by preventing...

for the vehicle's ventilation system forces air through the heater core to transfer heat from the coolant to the cabin air, which is directed into the vehicle through vents at various points.

Control

Once the engine has warmed up, the coolant is kept at a more or less constant temperature by the thermostat. The temperature of the air entering the vehicle's interior can be controlled by using a valve limiting the amount of coolant that goes through the heater core. Another method is blocking off the heater core with a door, directing part (or all) of the incoming air around the heater core completely, so it does not get heated. Some cars use a combination of this system.

Simpler systems allow the driver to control the valve or door directly (usually by means of a rotary knob, or a lever). More complicated systems use electronics

Electronics

Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

to control the valve or doors.

Cars with dual climate function (allowing driver and passenger to each set a different temperature) may use a heater core split in two, where different amounts of coolant flow through the heater core on either side to obtain the desired heating.

Air conditioning

In a car equipped with air conditioning

Air conditioning

An air conditioner is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. The cooling is done using a simple refrigeration cycle...

, outside air is first forced through the air conditioner's evaporator coil. This can be thought of as a heater core filled with very cold gas, which cools rather than heats the incoming air. In order to obtain the desired temperature incoming air may first be cooled by the air conditioning and then heated again by the heater core. In a vehicle fitted with manual controls for the heater and air conditioner, using both systems together will dehumidify the air in the cabin, as the evaporator coil removes moisture from the air due to condensation. This can result in increased air comfort levels inside the vehicle.

Engine cooling function

Because the heater core cools the heated coolant from the engine it can act as the radiator of the engine. If the radiator is working improperly, the operator may turn the heat on in the passenger cabin, resulting in cooling the engine coolant and then cooling the engine. This idea only works to a certain degree, as the heater core isn’t large enough nor does it have enough cold air going though it to cool large amounts of coolant significantly.

Possible problems

The heater core is made up of small piping that has numerous bends. Clogging of the piping may occur if the coolant system is not flushed or if the coolant is not changed regularly. If clogging occurs the heater core will not work properly. If coolant flow is restricted, heating capacity will be reduced or even lost altogether if the heater core becomes blocked. Control valves may also clog or get stuck.

Another possible problem is a leak in one of the connections to the heater core. This may first be noticeable by smell (ethylene glycol

Ethylene glycol

Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...

is widely used as coolant and has a sweet smell); it may also cause (somewhat greasy) fogging of the windshield

Windshield

The windshield or windscreen of an aircraft, car, bus, motorbike or tram is the front window. Modern windshields are generally made of laminated safety glass, a type of treated glass, which consists of two curved sheets of glass with a plastic layer laminated between them for safety, and are glued...

above the windshield heater vent. Glycol may also leak directly into the car, causing wet upholstery or carpeting.

Electrolysis

Electrolysis

In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

can cause excessive corrosion leading to the heater core rupturing. Coolant will spray directly into the passenger compartment followed with white colored smoke, a significant driving hazard.

Because the heater core is usually located under the dashboard inside of the vehicle and is enclosed in the ventilation system's ducting, servicing it often requires disassembling a large part of the dashboard, which can be time-consuming and therefore expensive.

Air cooled engines

Engines that do not have a water cooling system can not use a heater core; one alternative is to guide air around the (very hot) engine exhaust manifold

Exhaust manifold

In automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word manifold comes from the Old English word manigfeald and refers to the folding together of multiple inputs and outputs.In contrast, an inlet manifold is the part of an engine...

and then in to the vehicle's interior. Temperature control is achieved by mixing with unheated outside air. Depending on the design, this can cause a safety issue where a leak in the exhaust system will begin to fill the passenger cabin with deadly fumes.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

How it works

Control

Air conditioning

Engine cooling function

Possible problems

Air cooled engines

See also

External links