W Engine - The Modern "four-bank" Design

The Modern "four-bank" Design

Volkswagen Group created the first successful automotive W engine, with the introduction of its W8 (as a testbed for the W12). The W12 combines two narrow-angle VR6 engine cylinder heads around a single crankshaft for a total of four banks of cylinders. For this reason, the four-bank configuration is sometimes, and more accurately, referred to as a "VV" ("vee-vee" or "double-vee") or "VR", to distinguish it from the traditional three-bank "W" design (the earlier W8 combined two VR4 engines.)

The W8 was used in the B5.5 Volkswagen Passat and the W12 is used in the Volkswagen Phaeton, the Volkswagen Touareg, the Audi A8, and the Bentley Continental GT — though in the latter application, the engine has been highly modified by Bentley, and fitted with twin turbochargers. As a result, it produces considerably more power than the original version. The narrow (15°) angle between bank pairs makes this resemble a V12 engine, in that it has just two cylinder heads and two sets of camshafts. The W12 engine has bore-stroke of 84.0 millimetres (3.31 in) and 90.2 millimetres (3.55 in).

Volkswagen Group went on to produce a W16 engine prototype which produced 465 kilowatts (632 PS; 624 bhp) for the Bentley Hunaudières concept car. A quad-turbocharged version of this engine went into production in 2005 powering the 736 kilowatts (1,001 PS; 987 bhp) Bugatti Veyron EB16.4. The major advantage of these engines is packaging; that is, they contain high numbers of cylinders but are relatively compact in their external dimensions.