W18 engine
A W18 engine is an eighteen cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

 piston engine
Reciprocating engine
A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...

 which usually has a single crankshaft with three banks of six cylinders arranged in an inverted broad arrow configuration. Recent W18 engines powered the Bugatti EB 118, Bugatti EB 218 and Bugatti 18/3 Chiron
Bugatti 18/3 Chiron
The Bugatti 18/3 Chiron was a concept sports car designed by Giorgetto Giugiaro. It was a mid-engine design with the same W18 engine found in the EB 118 and EB 218 concept cars. The front resembles the Bugatti Veyron...

 concept cars in the late 1990s
File:1990s decade montage.png|From left, clockwise: The Hubble Space Telescope floats in space after it was taken up in 1990; American F-16s and F-15s fly over burning oil fields and the USA Lexie in Operation Desert Storm, also known as the 1991 Gulf War; The signing of the Oslo Accords on...

. This engine featured three banks of six cylinders set 60 degrees apart. The W18 engine was abandoned due to shifting problems.

The variation developed by Volkswagen
Volkswagen Group
Volkswagen Group is a German multinational automobile manufacturing group. , Volkswagen was ranked as the world’s third largest motor vehicle manufacturer and Europe's largest....

  retained the 18 cylinders but instead of three cylinder banks, it had four. This confused many who saw the specification in print at motor shows since 18 isn't evenly divisible by four. The design was loosely based on the concept Volkswagen used for its V5 engine
V5 engine
The V5 engine is a V form engine with five cylinders.- Volkswagen :Volkswagen introduced the first V5 engine, though this engine is not a true twin-bank V engine, but rather a VR5, or staggered bank straight-5 engine, and therefore not a true V5. It does not have one cylinder bank with 2 cylinders...

s which had one bank with three cylinders and one bank with only two. Essentially the four-bank W18 was two V9 engines (one bank of five cylinders and one bank of four) mated to a common crankshaft. Ultimately the design proved to be impractical.

An earlier example is the Isotta Fraschini Asso 750 used to power the Italian Savoia-Marchetti S.55
Savoia-Marchetti S.55
|-References:NotesBibliography* Yenne, Bill. Seaplanes & Flying Boats: A Timeless Collection from Aviation's Golden Age. New York: BCL Press, 2003. ISBN 1-932302-03-4.-External links:* *...

 seaplanes flown by Italo Balbo into Chicago in 1933. This engine used the same layout as the above-mentioned Bugatti - basically a vertical six with two adjacent banks set at 60 degrees each to make a W-18.

In 1967, Scuderia Ferrari
Scuderia Ferrari
Scuderia Ferrari is the racing team division of the Ferrari automobile marque. The team currently only races in Formula One but has competed in numerous classes of motorsport since its formation in 1929, including sportscar racing....

 built an experimental 500cc W3 engine in order to assess the potential for a 3-litre W18 Formula 1 engine. Although the engine developed 80 bhp at 11000rpm and 160 bhp per litre, the idea was abandoned, and subsequently, in 1972, Formula 1 rules were changed to outlaw the use of engines with more than 12 cylinders.

External links

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