A W engine is a type of piston engine where three or four cylinder banks use the same crankshaft, resembling the letter W when viewed from the front.[1][2][3]
W engines with three banks of cylinders are also called "broad arrow" engines, due to their shape resembling the British government broad arrow property mark.[1][4]
The most common W-type engine is the 4-bank type, with the Volkswagen Group experimenting with the Passat W8 and it’s 4.0 liter, 4-bank W8 engine and later implementing the concept with their Bentley division, creating a 6.0 liter W12 in both naturally aspirated and turbocharged variants. Due to the pre-existing VR-type engine only needing one cylinder head despite having two banks of cylinders, a Volkswagen 4-bank W-type engine is structured more similarly to a conventional 2-bank Vee engine as opposed to a “true” W engine.
W engines are significantly less common than V engines. Compared with a V engine, a W engine is typically shorter, but wider. In Volkswagen’s case, this allows for superior packaging in engine compartments intended for 6 and 8 cylinder engines, the Passat W8 being one such example.
- ^ a b Domonoske, Arthur Boquer; Finch, Volney Cecil (1936). Aircraft engines: theory, analysis, design, and operation (Engineering textbook). J. Wiley & Sons. p. 7. Retrieved 2014-04-25.
The W, or broad arrow engine, has three rows of cylinders of which the central row is vertical with the other two rows forming equal angles with the vertical.
- ^ Taylor, Charles Fayette (1985) [1968]. The Internal-combustion Engine in Theory and Practice: Combustion, fuels, materials, design. Massachusetts Institute of Technology. ISBN 0-262-70027-1. LCCN 84028885. Retrieved 2013-12-17.
W engine is similar to a V engine but with three banks of cylinders. The two V angles are usually equal.
- ^ Rajput, R. K. (December 2005). Internal Combustion Engines. New Delhi, India: Laxmi Publications. ISBN 817008637X. Retrieved 2013-12-17.
W-engine Same as V-engine except with three banks of cylinders on the same crankshaft.
- ^ "The New Sunbeam Overhead Valve Type Engines", Aviation Week and Space Technology, vol. 3, McGraw-Hill, p. 32, 1917