AW18 engine is an eighteen-cylinderpiston engine with three banks of six cylinders in aW configuration.
The W18 layout is rarely used, with the only production examples being several aircraft during the 1920s and 1930s. Prototype W18 engines were produced for concept cars predecessors to the Bugatti Veyron in the late 1990s.
The first example was the GermanMercedes D.VI aeroengine, which were built since 1915.A later example is the 1929Hispano-Suiza 18R, an aircraft racing engine produced in limited quantities in France.[1] This was followed in 1934 by theIsotta Fraschini Asso 750, which was built in Italy and used in several flying boats.[2] The Asso 750 was water-cooled and used an angle of 60 degrees between banks. The 1943 Tatra T955 was a prototype diesel aircraft engine which used a W18 layout.[citation needed]
The W18 layout has rarely been considered for use in motor vehicles by car manufacturers, and none have reached production.
In 1967,Scuderia Ferrari built a prototypeW3 engine as a feasibility study for a 3.0 L (183 cu in) W18 engine to use in Formula One.[3]
A W18 was considered as a flagship option for theMercedes-Benz W140 S-Class and a potential futuresupercar to supersede theM120 V12, which was still being developed at the time. Internally classified as the M216, it was to share many internal components with existing Mercedes-Benzinline-six engines in order to save on development and production costs. Development of the engine was halted when prototypes of the M120 engine proved satisfactory, and it was decided there was no need for a larger engine.[4]
In the late 1990s, theBugatti EB 118,Bugatti EB 218,Bugatti 18/3 Chiron andBugatti EB 18/4 Veyron concept cars were fitted with W18 engines,[5][6] prior to the production version of the Bugatti Veyron using aW16 engine instead.
In 2025,Porsche filed a patent for a W18 with intake manifolds atop each cylinder head. The patent also details the potential for turbocharging.[7][8]
The W18 layout has been used on the high seas;CRM Motori SpA marine engines.
