Audi’s Cylinder Deacativation Technology

Audi’s use of cylinder deactivation technology (coined by the brand as Cylinder on Demand – CoD), means it can effectively half the number of cylinders used by the engine. But how does it work? The video below explains just how this simple yet effective system is managed.

Simple as it may look, what is the point of the shutting down of four cylinders? Well the answer is simple: to save fuel.

Using the V8 engine of Audi’s powerful S8 super saloon as an example, for a large percentage of journeys made in the developed world, having 512bhp is almost pointless. When cruising on the motorway, edging forward in traffic or even steadily increasing speed, forcing fuel into all eight cylinders of the S8’s engine would be unnecessary.

Audi has therefore developed this technology to an advanced stage, enabling it to use significantly less fuel by cutting off fuel injection to half of the engine’s cylinders. Running on four of the S8’s cylinders provides more than adequate power, but most impressively allows the car to achieve a combined mpg figure of 28. For a car that weighs just shy of two metric tons and holds a four-litre engine under the bonnet, that figure is undeniably impressive.

With global pressure increasing on lowering the emissions of vehicles, the resulting 235 grams of CO2/km is also of significant importance. Even though this figure is still fairly large, considering the size of the S8 it is another impressive feat. And with this technology making its way into smaller cars in the Audi range, it is exciting to think of the combination of power and efficiency future models can posses, emitting significantly reduced CO2 levels without compromising performance. In fact, the technology has already been fitted to Audi’s baby hatchback, the A1, allowing it to produce an impressive 120bhp from a 1.4-litre engine whilst emitting just 126 grams of CO2/km.

No doubt the mixing of performance with efficiency is certainly an attractive prospect for all drivers, so including this CoD technology throughout the Audi range would be a very welcome prospect.

Sources: [Online] Available at:

Audi News. [Online] Available at:


About sam sheehan Freelance automotive writer and MA Automotive Journalism student


  1. What a thing! Valve stems are disconnected through specially designed movable camshaft profiles! Def. has a future that engine!

  2. Agreed, if only it was standard practice on more cars. Economy with uncompromised performance sounds good to me!

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