A W engine is a reciprocating piston engine with three banks of cylinders that are arranged in the shape of a "W" (with equal opening angles less than 90 °), which - similar to the V engine - accommodates more cylinders with the same engine length can. The classic W-engine according to the engine theory has three rows of cylinders (analogous to the V-engine with two rows of cylinders also called Y-engine), while the engine design designated by Volkswagen AG as "W" consists of four rows of cylinders with different opening angles and thus according to engine construction theory a double V engine or more precisely a double VR engine (here with a crankshaft).
The disadvantage is the direct vicinity of the hot exhaust system of the middle cylinder bank with fuel-carrying parts of the intake system of one of the outer cylinder banks. In the W engine, the forces from three pistons are also transferred to a single crank pin via connecting rods, which means that large crankshaft cross-sections are required.
Use of W motors
Classic W motor (Y motor)
An example of a classic W engine with three rows of cylinders at the same angle ( Y engine ) is the motorcycle racing engine made by the French motorcycle manufacturer Alcyon in 1904 . With him the three cylinders had an angle of 45 ° to each other. Alessandro Anzani drove a machine with this unusual engine. The Curtiss 10 hp , published in 1907 , had cylinders at an angle of 50 degrees.
- The only W engines from the Volkswagen Group that can correctly be referred to as W engines are that of the Audi W12 super sports car prototype Avus quattro (1991) and the W18 engine of the Bugatti Chiron 18.3 prototype (1999). All current engines marked with "W" have four rows of cylinders and are of the double V design (V-VR design).
- Other examples of W engines (Y engines) are the twelve-cylinder Napier Lion , the W18 engines from Isotta Fraschini ( Asso 750 and Asso 1000 ) and from CRM Spa Motori Marini ( 18 D / SS BR-2 with 40 ° / 40 ° cylinder bank angles) and Guy Nègre's W12 Formula 1 engine. The Lion engines achieved some fame through their use in racing planes (Supermarine p. 5 in Schneider Trophy ), as well as in record vehicles (including by Malcolm Campbell ).
- In Rumpler Tropfenwagen at the beginning of the 1920s was initially installed W6 a motor, in which the six cylinders in the W were arranged with 60 ° opening angle and poured together in pairs.
- In the 1950s, Mitsubishi built a 24-cylinder W two-stroke diesel under the name W24-WZ as a test engine for speedboats. The engine developed 2200 kW (2991 hp) at 1600 revolutions per minute.
- The small French company Moteurs Guy Nègre (MGN) designed a 3.5- liter 60 ° / 60 ° W12 engine for use in Formula 1 at the end of the 1980s . The engine was equipped with three rows of four cylinders each, had no conventional valves and should produce around 630 hp at 15,000 revolutions per minute . The project became known at the beginning of 1989, but after unsuccessful test drives in an AGS JH22 chassis and due to financial and technical problems, it was discontinued without having driven a single racing kilometer. Later the MGN W12 (Moteurs Guy Nègre) was used in a Norma M6 sports car. Guy Nègre has now developed an air motor .
- The only W-configuration Formula 1 engine used at Grand Prix events is a Life Racing W12 engine . The former Ferrari engineer Franco Rocchi, who designed the legendary eight-cylinder of the brand in the 1970s, built a twelve-cylinder naturally aspirated engine with three rows of four cylinders each in the late 1980s. Apart from the cylinder arrangement, the concept of the engine was conservative; Rocchi's engine did not have any special features as planned by Guy Nègre. The Rocchi-W12 was developed at a time when Formula 1 was reorienting itself. Turbo engines were banned after the last race of the 1988 season; all teams had to use naturally aspirated engines again. During this time, it was initially not clear which number of cylinders and which concept would be the most successful. Therefore, some manufacturers tried different ideas. In 1989 eight, ten and twelve-cylinder cylinders with different cylinder bank angles were seen , Motori Moderni , for example, tried a boxer concept with a 180 ° cylinder bank angle for Subaru , which was used unsuccessfully by the Coloni team in 1990 . Rocchi's W engine was another variant, albeit conceptually the extreme idea. The Italian businessman Ernesto Vita acquired the rights to the engine and tried in the course of 1988 to win a Formula 1 team to use the engine in the 1989 season. There were talks with Coloni, but they were unsuccessful. Other teams also refused. Ultimately, Vita had to found its own racing team, Team Life Racing, which competed with a used car and Rocchi's engine in the 1990 season. What was intended as an attempt to convince other teams of the success of the concept soon turned into a disaster: the engine was not efficient; Employees spoke behind closed doors of 450 hp, which hardly corresponded to the level of performance of the Formula 3000. In addition, the engine was not resilient. Whenever the drivers Gary Brabham or Bruno Giacomelli pushed into higher speed ranges, the engine exploded. Rarely did the drivers manage a full timed lap.
Fake W engines (double V engines) in the Volkswagen Group
The top model of the VW Passat was equipped with a W8 engine and all-wheel drive between 2001 and 2004. It is a double V engine with two VR4 cylinder banks.
The VW W12 Coupé was developed in collaboration with Italdesign between 1997 and 2002 with a W12 engine, but did not go into series production. From 2001 onwards , he set up several world records and international class records on the high-speed track in Nardò , hence the later name Nardo.
The Volkswagen Group's first production vehicle with a W12 engine is the Audi A8 , which was available with this engine from 2001 to 2017. The VW Phaeton was available with a W12 engine between 2002 and 2011, the first generation of the VW Touareg was also available with a W12 engine from 2004 to 2010.
The Volkswagen Group currently offers the W12 engine in the following models:
In spring 2007, the Golf GTI W12-650 designed by VW as a show car with a W12 mid-engine , an output of 478 kW (650 hp) and a top speed of 325 km / h was presented at the annual GTI meeting at Wörthersee .
The "W16" with a maximum output of 883 kW (1200 PS) in the Bugatti Veyron 16.4 is a double V engine with two VR8 cylinder banks (15 degree cylinder angle, 90 degree bank angle). This arrangement of the cylinders made it possible to construct a space-saving 16-cylinder engine with a displacement of 7,993 cm³. The engine is equipped with four exhaust gas turbochargers (hence 16.4). For the successor model, the Bugatti Chiron , presented in 2016 , it has been completely revised, according to Bugatti, and its output increased by 25% to 1103 kW (1500 PS).
- The new W engines from Volkswagen with 8 and 12 cylinders. In: Motortechnische Zeitschrift No. 62, 2001.
- Spyker C12 Spyder. With the power of an Audi. spiegel.de from December 12, 2004, accessed on August 8, 2018