Description
The name VR6 comes from the combination of German words "Verkürzt" and "Reihenmotor" meaning "shortened inline engine"
This engine configuration can also be described as a "staggered six", in keeping with the narrow angle geometry of the Lancia Fulvia staggered-four, developed in the late-1950s (a continuation of Lancia's V4 design practice dating back to the 1920s).
The Volkswagen VR6 was specifically designed for transverse engine installations in front-wheel drive vehicles. The narrow angle of 15° between the two 'rows' in the VR6 engine is a more compact size than a conventional V6 design. This made it possible for Volkswagen to install six-cylinder engines in existing four-cylinder cars. The wider configuration of a conventional V6 engine would have required an extensive redesign of the vehicles to enlarge the engine compartment. The VR6 is also able to use the firing order of a straight-six engine.
The narrow angle between cylinders allows the use of just one 'cylinder bank', and one cylinder head - whereas conventional Vee engines have two cylinder banks and require two separate cylinder heads. This arrangement also allows for two overhead camshafts to drive all the valves. This simplifies engine construction and reduces costs. In early 12 valve VR6 engines, there were two overhead camshafts with six cam lobes on each. The forward camshaft has three intake valve lobes and three exhaust valve lobes to control the frontmost three cylinders. The rear camshaft is designed the same way, but controls the rearmost three cylinders. The operating principle of this design is most similar to a single overhead camshaft (SOHC) design. Later 24 valve VR6 engines still had two overhead camshafts, but with 12 cam lobes each. However, the operation of the camshafts in the 24 valve engine is different from that of the earlier 12 valve engine, in that the front camshaft only operates the intake valves, and the rear camshaft only operates the exhaust valves. The operating principle of this design is most similar to a double overhead camshaft (DOHC) design.
There are several different variants of the VR6 engine. The original VR6 engine displaced 2.8 litres and featured a 12 valve design (two valves per cylinder). These engines produced a DIN-rated power output of 128 kW (174 PS; 172 bhp), and 240 N·m (177 lbf·ft) of torque.
Read more about this topic: VR6 Engine
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