A straight-12 engine or inline-12 engine is a twelve-cylinder

piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...

with all twelve

cylinders A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infini ...

mounted in a straight line along the

crankcase In a piston engine, the crankcase is the housing that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block. Two-stroke engines typically use a crankcase-compression design, resulting in the fuel/a ...

Land use

Due to the very long length of a straight-twelve engine, they are rarely used in automobiles. The first known example is a engine in the 1920 French ''Corona'' car; however it is not known if any were cars sold.

Packard Packard or Packard Motor Car Company was an American luxury automobile company located in Detroit, Michigan. The first Packard automobiles were produced in 1899, and the last Packards were built in South Bend, Indiana in 1958. One of the "Thr ...

also experimented with an automobile powered by an inline 12 in 1929. The straight-12 has also been used for large military trucks.

Marine use

Some Russian firms built straight-12s for use in ships in the 1960s and 1970s. MAN Diesel & Turbo 12K98ME and 12S90ME-C and the

Wärtsilä-Sulzer RTA96-C The Wärtsilä RT-flex96C is a two-stroke turbocharged low-speed diesel engine designed by the Finnish manufacturer Wärtsilä. It is designed for large container ships that run on heavy fuel oil. Its largest 14-cylinder version is 13.5 meters ...

are examples of contemporary marine engines in L-12-cylinder configuration. These are popular for propulsion in container ships.

References

Piston engine configurations 12-cylinder engines 12 {{Mech-engineering-stub