W8 engine
Encyclopedia
A W8 engine is an eight-cylinder
piston
internal combustion engine
in a W configuration
.
The W8 can be imagined as flat plane crank V8 engine
combining two narrow-angle (15 degree) V4 engine
blocks, mounted juxtaposed at 72 degrees to each other and coupled to one crankshaft
. Nearly-square external dimensions mean the large eight cylinder engine will fit in the space typically taken by a V6 engine
.
in the Volkswagen Passat (B5.5) from September 2001 to September 2004, but sales were minimal at only 10,000 units worldwide per year. The Passat W8 was positioned as Volkswagen Passenger Cars'
"premium" car, before the Volkswagen Phaeton
was introduced.
The 4.0 litre
- 3998 cc W8 engine produced 202 kW at 6,000 revolutions per minute
(rpm) and 370 newton metres (273 ft·lbf) of torque
at 2,750 rpm, yet was considered a fuel-efficient eight cylinder engine due to the design. It also had a two stage resonance induction system to boost cylinder filling across the engine speed range. It had two simplex roller chain
-driven (relay method, using three chains) double overhead camshaft (two overhead camshaft
s per cylinder bank
, hence "quad cam"), and twin balance shafts to smooth out residual vibrations inherent in the layout. One additional advantage was that the W8 shared some components and machining with narrow-angle VR5 and VR6
engines, leading to cost reduction in one of the most expensive engines Volkswagen Passenger Cars has ever produced.
The 2006 redesign of the Passat (B6) changed the engine's mounting configuration to transverse
. The W8 is too large physically to be mounted in such a way, so the 'large' 3.6 litre VR6 engine has replaced its position at the top of the range.
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
piston
Reciprocating engine
A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...
internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
in a W configuration
W engine
A W engine is a type of reciprocating engine arranged with its cylinders in a configuration in which the cylinder banks resemble the letter W, in the same way those of a V engine resemble the letter V....
.
The W8 can be imagined as flat plane crank V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....
combining two narrow-angle (15 degree) V4 engine
V4 engine
A V4 engine is a V form engine with four cylinders and three main bearings.-Automobile use:Lancia produced several narrow-angle V4 engines from the 1920s through 1960s for cars like the Lambda, Augusta, Artena, Aprilia, Ardea, Appia, and Fulvia....
blocks, mounted juxtaposed at 72 degrees to each other and coupled to one crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
. Nearly-square external dimensions mean the large eight cylinder engine will fit in the space typically taken by a V6 engine
V6 engine
A V6 engine is a V engine with six cylinders mounted on the crankcase in two banks of three cylinders, usually set at either a right angle or an acute angle to each other, with all six pistons driving a common crankshaft...
.
Volkswagen W8 engine
The Volkswagen Group W8 engine was installed longitudinallyLongitudinal engine
In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back....
in the Volkswagen Passat (B5.5) from September 2001 to September 2004, but sales were minimal at only 10,000 units worldwide per year. The Passat W8 was positioned as Volkswagen Passenger Cars'
Volkswagen
Volkswagen is a German automobile manufacturer and is the original and biggest-selling marque of the Volkswagen Group, which now also owns the Audi, Bentley, Bugatti, Lamborghini, SEAT, and Škoda marques and the truck manufacturer Scania.Volkswagen means "people's car" in German, where it is...
"premium" car, before the Volkswagen Phaeton
Volkswagen Phaeton
The Volkswagen Phaeton is a full-size luxury sedan/saloon manufactured by German automaker Volkswagen, and is described by Volkswagen as their "premium class" vehicle...
was introduced.
The 4.0 litre
Litre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
- 3998 cc W8 engine produced 202 kW at 6,000 revolutions per minute
Revolutions per minute
Revolutions per minute is a measure of the frequency of a rotation. It annotates the number of full rotations completed in one minute around a fixed axis...
(rpm) and 370 newton metres (273 ft·lbf) of torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
at 2,750 rpm, yet was considered a fuel-efficient eight cylinder engine due to the design. It also had a two stage resonance induction system to boost cylinder filling across the engine speed range. It had two simplex roller chain
Roller chain
Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire and tube drawing machines, printing presses, cars, motorcycles, and simple machines like...
-driven (relay method, using three chains) double overhead camshaft (two overhead camshaft
Overhead camshaft
Overhead cam valvetrain configurations place the engine camshaft within the cylinder heads, above the combustion chambers, and drive the valves or lifters in a more direct manner compared to overhead valves and pushrods...
s per cylinder bank
Cylinder bank
Internal combustion piston engines are usually arranged so that the cylinders are in lines parallel to the crankshaft. Where they are in a single line, this is referred to as an inline or straight engine....
, hence "quad cam"), and twin balance shafts to smooth out residual vibrations inherent in the layout. One additional advantage was that the W8 shared some components and machining with narrow-angle VR5 and VR6
VR6 engine
The VR6 engine is an internal combustion engine configuration, consisting of six cylinders. It was developed by the Volkswagen Group in the late 1980s, and evolutions of the original variant are still produced by them....
engines, leading to cost reduction in one of the most expensive engines Volkswagen Passenger Cars has ever produced.
The 2006 redesign of the Passat (B6) changed the engine's mounting configuration to transverse
Transverse engine
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the long axis of the vehicle. Many modern front wheel drive vehicles use this engine mounting configuration...
. The W8 is too large physically to be mounted in such a way, so the 'large' 3.6 litre VR6 engine has replaced its position at the top of the range.