The VR5 engines are a family of petroleum fuelled

Internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...

s developed by the

Volkswagen Group Volkswagen AG (), known internationally as the Volkswagen Group, is a German multinational automotive manufacturer headquartered in Wolfsburg, Lower Saxony, Germany. The company designs, manufactures and distributes passenger and commercia ...

and produced from 1997 to 2006. They are derived from the VR6 engine family, also developed by

Volkswagen Volkswagen (),English: , . abbreviated as VW (), is a German Automotive industry, motor vehicle manufacturer headquartered in Wolfsburg, Lower Saxony, Germany. Founded in 1937 by the German Labour Front under the Nazi Party and revived into a ...

, but with one less cylinder. VR5 engines are narrow-angle V5

petrol engine A petrol engine (gasoline engine in American English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends (such as ' ...

s, with a V angle of 15° and a displacement of . The VR5 was the first production block to use five cylinders in a V design with a 15-degree angle.

Technical Information

A VR5 engine block consists of two

cylinder A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an ...

banks, one bank containing three cylinders and the other containing two. In a

transverse Transverse may refer to: *Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle * Transverse flute, a flute that is held horizontally * Transverse force (or ''Euler force''), the tange ...

layout the three cylinder bank is located towards the front and in a

longitudinal Longitudinal is a geometric term of location which may refer to: * Longitude ** Line of longitude, also called a meridian * Longitudinal engine, an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, ...

layout towards the right. Due to the narrow angle the cylinder arrangement appears like a staggered inline five cylinder. The engines have a firing order of 1-2-4-5-3. The VR5 was initially made with 2 valves per cylinder as the AGZ engine from 1997 until 2000, resulting in a 10 valve engine producing at 6000 RPM and of torque at 3200 RPM. The engine was updated in 2000 as the AQN/AZX engine adding an additional 2 valves per cylinder and variable valve timing, resulting in an 20 valve engine now with 4 valves per cylinder, producing at 6200 RPM and at 3300 RPM. Both versions of the engine had cast aluminium alloy

cylinder head In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas in more modern o ...

s and cast iron cylinder blocks.

AGZ engine

Valvetrain and cylinder head

The AGZ engine was the first version of the VR5. It had ten valves in total, with two unequal sized valves per cylinder and chain driven camshafts. Due to the use of a single

, a key design principle of the VR engines, exhaust and intake ports were of unequal length between the two cylinder banks. To mitigate this, Volkswagen used unequally sized valves to ensure even flow and power output from the cylinders.

Engine block and pistons

The AGZ engine used a cast iron cylinder block with five staggered cylinders. Each cylinder was bore x stroke, resulting in per cylinder with a 0.90:1 stroke ratio (undersquare/long stroke). The top of each piston was angled to accommodate for the use of the 15° narrow V angle.

Aspiration, fuel system, and engine management

The AGZ engine was managed by a Bosch Motronic M3.8.3 engine management system. The engine used multi-point common rail sequential fuel injection, with fuel injected indirectly into the lower intake manifold section just before the cylinder head intake ports. Fuel and air delivery was controlled by a cable operated throttle body, with a potentiometer monitoring throttle position and allowing the Motronic ECU to deliver the correct amount of fuel. The engine also had a vacuum actuated variable intake manifold, controlled by the ECU via a valve part of the engines vacuum system. The valve is opened and closed depending on engine load, engine speed and throttle position. This allows the engine to take advantage of pressure waves created by the intake valves opening and closing.
The VR5 was used in the Volkswagen

Golf Golf is a club-and-ball sport in which players use various clubs to hit balls into a series of holes on a course in as few strokes as possible. Golf, unlike most ball games, cannot and does not use a standardized playing area, and coping wi ...

, Bora, New Beetle and Passat. The engine was also included in the Toledo, a saloon car made by Volkswagen Group's subsidiary SEAT.

References

{{reflist Volkswagen Group engines Piston engine configurations V5 engines V engines