The W12 engine is a type of internal combustion engine that has 12 cylinders arranged in a W-shaped configuration. It is a rare and powerful engine that is used in some high-performance cars from Volkswagen, Audi, and Bentley. In this article, we will explain what a W12 engine is, how it works, what are its advantages and disadvantages, and what are some of the cars that use it.
What is a W12 Engine?
A W12 engine is a 12-cylinder piston engine where either three banks of four cylinders, or four banks of three cylinders are arranged in a W configuration around a common crankshaft. The W12 engine is derived from the VR6 engine, which is a narrow-angle V6 engine that uses a single cylinder head for each bank of cylinders. By combining two VR6 engines at a 72-degree angle, a W12 engine is formed. The W12 engine has the same number of camshafts as a V12 engine, but it is more compact and shorter in length.
The W12 engine was first used in aircraft engines in the early 20th century, such as the Napier Lion and the Farman 12We. However, it was not until the late 20th century that the W12 engine was revived for automotive use by the Volkswagen Group. The first car to use the W12 engine was the 2001 Audi A8, followed by the 2003 Bentley Continental GT, the 2004 Volkswagen Phaeton, the 2005 Volkswagen Touareg, and the 2015 Bentley Bentayga. The W12 engine is also used in some low-volume sports cars from Spyker.
How Does a W12 Engine Work?
A W12 engine works by using four strokes of the piston to complete one cycle of combustion: intake, compression, power, and exhaust. During the intake stroke, the piston moves down and draws air and fuel into the cylinder. During the compression stroke, the piston moves up and compresses the air-fuel mixture. During the power stroke, the spark plug ignites the mixture and the piston is pushed down by the expanding gases. During the exhaust stroke, the piston moves up and pushes the burned gases out of the cylinder.
The W12 engine has two banks of six cylinders on each side of the crankshaft, and each bank has two rows of three cylinders. The cylinders are offset from each other, so that the pistons do not share the same crankpin. This reduces the length of the crankshaft and the vibration of the engine. The W12 engine also uses a dry sump lubrication system, which means that the oil is stored in a separate tank and pumped to the engine, rather than being stored in the oil pan. This improves the cooling and lubrication of the engine, and allows it to be mounted lower in the car.
The W12 engine can be naturally aspirated or turbocharged, depending on the model of the car. The turbocharged version uses two turbochargers, one for each bank of cylinders, to increase the power and torque of the engine. The turbochargers also have intercoolers, which cool down the compressed air before it enters the cylinders, to improve the efficiency and performance of the engine.
What are the Advantages and Disadvantages of a W12 Engine?
The W12 engine has several advantages and disadvantages compared to other types of engines. Some of the advantages are:
- It is very powerful and smooth, as it has 12 cylinders firing in a balanced sequence.
- It is very compact and lightweight, as it has a short crankshaft and a narrow angle between the cylinders.
- It has a low center of gravity, as it can be mounted lower in the car due to its dry sump system.
- It has a unique and distinctive sound, as it combines the growl of a V6 with the roar of a V12.
Some of the disadvantages are:
- It is very expensive and complex, as it has many parts and requires high-quality materials and engineering.
- It is very thirsty and polluting, as it consumes a lot of fuel and emits a lot of carbon dioxide.
- It is very rare and exclusive, as it is only used in a few models of cars from a few brands.
What are Some of the Cars that Use a W12 Engine?
The W12 engine is used in some of the most luxurious and powerful cars in the world, such as:
- Audi A8: The flagship sedan of Audi, which uses a 6.0 L W12 engine that produces 450 hp and 580 Nm of torque.
- Bentley Continental GT: The grand tourer coupe of Bentley, which uses a 6.0 L twin-turbocharged W12 engine that produces 626 hp and 900 Nm of torque.
- Bentley Continental Flying Spur: The luxury sedan of Bentley, which uses a 6.0 L twin-turbocharged W12 engine that produces 626 hp and 900 Nm of torque.
- Bentley Bentayga: The luxury SUV of Bentley, which uses a 6.0 L twin-turbocharged W12 engine that produces 600 hp and 900 Nm of torque.
- Volkswagen Phaeton: The luxury sedan of Volkswagen, which uses a 6.0 L W12 engine that produces 444 hp and 560 Nm of torque.
- Volkswagen Touareg: The mid-size SUV of Volkswagen, which uses a 6.0 L W12 engine that produces 444 hp and 600 Nm of torque.
- Spyker C12 La Turbie: The sports car of Spyker, which uses a 6.0 L W12 engine that produces 500 hp and 610 Nm of torque.
- Spyker C12 Zagato: The sports car of Spyker, which uses a 6.0 L W12 engine that produces 500 hp and 610 Nm of torque.
Characteristics of the W12 Engine
The following table summarizes some of the main characteristics of the W12 engine:
| Characteristic | Value |
|---|---|
| Configuration | 72° W-12 |
| Displacement | 6.0 L (5,998 cc) |
| Cylinder bore | 84 mm (3.31 in) |
| Piston stroke | 90.2 mm (3.55 in) |
| Valvetrain | 48-valve, DOHC, four-valves per cylinder |
| Compression ratio | 10.7:1 |
| Turbocharger | Twin-turbocharged (optional) |
| Fuel system | Fuel injection |
| Fuel type | Gasoline |
| Oil system | Dry sump |
| Power output | 414–700 hp (309–522 kW) |
| Torque output | 405–750 lb⋅ft (549–1,017 N⋅m) |
| Dry weight | 239 kg (527 lb) |
FAQ
Q: What is the difference between a W12 and a V12 engine?
A: A W12 engine is a 12-cylinder engine that has four banks of three cylinders, while a V12 engine is a 12-cylinder engine that has two banks of six cylinders. A W12 engine is more compact and lighter than a V12 engine, but it is also more complex and expensive.
Q: How many W12 engines are produced per year?
A: According to the Volkswagen Group, the W12 engine is produced at a rate of about 5,000 units per year at its factory in Germany. The W12 engine is mainly used for the Bentley models, which account for about 80% of the production.
Q: What is the fastest car that uses a W12 engine?
A: The fastest car that uses a W12 engine is the Bentley Continental GT Speed, which can reach a top speed of 331 km/h (206 mph). The car uses a 6.0 L twin-turbocharged W12 engine that produces 650 hp and 900 Nm of torque.
