- Air-cooled engine
Air-cooled engines rely on the circulation of air directly over hot parts of the
engineto cool them.
internal combustion engines are cooled by a closed circuit carrying liquid coolant through channels in the engine block, where the coolant absorbs heat, to a heat exchangeror radiatorwhere the coolant releases heat into the air. Thus, while they are "ultimately" cooled by air, because of the liquid-coolant circuit they are known as "water-cooled". In contrast, heat generated by an air-cooled engine is released directly into the air. Typically this is facilitated with metal fins covering the outside of the cylinders which increase the surface area that air can act on.
In all combustion engines, a great percentage of the heat generated (around 44%) escapes through the exhaust, not through either a liquid cooling system nor through the metal fins of an air-cooled engine (12%). About 8% of the heat energy finds its way into the oil, which although primarily meant for
lubrication, also plays a role in heat dissipation via a cooler. [http://www.avweb.com/news/maint/182883-1.html]
motorcycles use air-cooling for the sake of reducing weight and complexity. Few current production automobiles have air-cooled engines, but historically it was common for many high-volume vehicles. Examples of past air cooled road vehicles include:
* VW-Porsche 914 (1969-1976)
Porsche 911(1964-1998) (While the 911 and the 914 are classified as air-cooled, they are in fact oil-cooled vehicles, with hot oil circulated to an external oil cooler for cooling. This may be true of other air-cooled automobiles)
Volkswagen Beetle, Type 2, SP2, Karmann Ghia, and Type 3 all utilized the same air cooled engine (1938-2003) with various displacements.
Volkswagen Type 4(1968-1974)
Citroën 2CV(1948-1990) (Featured a high pressure oil cooling system, and used a fan that was both axial and radial).
* Some early
* The East German
Tatra (company)all wheel drive military trucks.
piston engines are air-cooled, including most of the engines currently (2005) manufactured by Lycoming and Continental and used by major manufacturers of light aircraft Cirrus, Cessnaand so on. Notable exceptions have included the Allison V-1710and Rolls-Royce series of (most well known, the Merlin V-1650) liquid-cooled V12 engines which powered P-51 Mustangs, Avro Lancasters, Hawker Hurricanes and Spitfires.
Other engine manufactures using air-cooled engine technology are
ULPowerand Jabiru, more active in the Light-Sport Aircraft (LSA) and ultralight aircraftmarket. Rotaxuses a combination of air-cooled cylinders and liquid cooled cylinder heads.
Some small diesel engines, e.g. those made by
Deutz AGand Lister Petterare air-cooled.
Wikimedia Foundation. 2010.
Look at other dictionaries:
air cooled engine — An engine which generally has large fins or ribs and is often exposed to the outside air. The heat of the engine is dissipated through the fins of the engine. In contrast, the heat in a liquid cooled engine is reduced by channels throughout the… … Dictionary of automotive terms
air-cooled engine — A reciprocating engine that depends on cooling by the air mass rather than on liquid coolants. The cooling is directed by radiating heat to the air flowing between the fins around the cylinder head or around a hot rotor casing in the case of a… … Aviation dictionary
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air-cooled — [er′ko͞old΄] adj. 1. cooled by having air passed over, into, or through it [an air cooled engine] 2. air conditioned * * * … Universalium
air-cooled — [er′ko͞old΄] adj. 1. cooled by having air passed over, into, or through it [an air cooled engine] 2. air conditioned … English World dictionary
air-cooled — adjective cooled by a flow of air an air cooled engine • Similar to: ↑cool * * * adjective see air cool * * * airˈ cooled adjective • • • Main Entry: ↑air * * * … Useful english dictionary
air-cooled — ADJ: usu ADJ n An air cooled engine is prevented from getting too hot when it is running by cool air that passes over it, rather than being cooled by a liquid. The car was powered by a four cylinder air cooled engine … English dictionary
cooled engine — See air cooled engine … Dictionary of automotive terms
air cooled — See air cooled engine … Dictionary of automotive terms
Air-cooled — Air cooling Air cooling In devices generating heat, such as gasoline engine motor vehicles, the cooling of the device by increasing its radiating surface by means of ribs or radiators, and placing it so that it is exposed to a current of air. Cf … The Collaborative International Dictionary of English