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 combus ...

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 commercial ...

and produced from 1997 to 2006. They are derived from the

VR6 engine VR6 engines are V6 piston engines with a narrow angle between the cylinder banks and a single cylinder head covering both banks of cylinders. Volkswagen Group introduced the first VR6 engine in 1991 and VR6 engines currently remain in producti ...

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 ''E ...

s, with a V angle of 15° and a

displacement Displacement may refer to: Physical sciences Mathematics and Physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...

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 infin ...

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 tangen ...

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 ov ...

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

camshaft A camshaft is a shaft that contains a row of pointed cams, in order to convert rotational motion to reciprocating motion. Camshafts are used in piston engines (to operate the intake and exhaust valves), mechanically controlled ignition systems ...

s. 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 In a reciprocating piston engine, the stroke ratio, defined by either bore/stroke ratio or stroke/bore ratio, is a term to describe the ratio between cylinder bore diameter and piston stroke length. This can be used for either an internal com ...

(undersquare/long stroke). The top of each

piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tig ...

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 An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by re ...

. The engine used multi-point common rail sequential

fuel injection Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All comp ...

, with fuel injected indirectly into the lower

intake manifold In automotive engineering, an inlet manifold or intake manifold (in American English) is the part of an engine that supplies the fuel/air mixture to the cylinders. The word ''manifold'' comes from the Old English word ''manigfeald'' (from the ...

section just before the cylinder head intake ports. Fuel and air delivery was controlled by a cable operated

throttle body A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ...

, 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 The Volkswagen New Beetle is a compact car, introduced by Volkswagen in 1997, drawing heavy inspiration from the exterior design of the original Beetle. Unlike the original Beetle, the New Beetle has its engine in the front, driving the fron ...

and

Passat The Volkswagen Passat is a series of large family cars manufactured and marketed by the German automobile manufacturer Volkswagen since 1973, and now in its eighth generation. It has been marketed variously as the Dasher, Santana, Quantum, Mago ...

. The engine was also included in the Toledo, a saloon car made by Volkswagen Group's subsidiary

SEAT A seat is a place to sit. The term may encompass additional features, such as back, armrest, head restraint but also headquarters in a wider sense. Types of seat The following are examples of different kinds of seat: * Armchair (furniture), ...

References

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