Volkswagen has announced details of a new 1.4-litre TSI petrol engine that can shut down two of its four cylinders to cut fuel consumption and emissions.
Full specifications are yet to be revealed, but Volkswagen says that official fuel economy improves by about 3mpg compared with a normal 1.4-litre TSI engine.
Using the 121bhp 1.4 TSI in the Golf as an example, average fuel economy will be boosted from 45.6mpg to 48.7mpg, an improvement of just over 7%. CO2 emissions should be reduced by a similar amount, leading to a potential reduction from 144g/km to 134g/km.
Cylinder shut-off occurs between 1400 and 4000rpm, and when torque is between 18 and 55lb ft. Under the EU driving cycle to deteremine a cars fuel economy, the new 1.4 TSI would be running on two cylinders for 70% of the test distance.
Constant and moderate speeds bring about the greatest benefits from the technology. Volkswagen claims the new engine is still very quiet and low in vibration when running on two cylinders.
The cylinders reactivate as soon as the driver requires more power. If the system detects a sporty style of driving, it will remain in four-cylinder mode.
Volkswagen hasnt confirmed which models will be available with the new technology, or whether the new engine will replace an existing one. The new 1.4 TSI models will be available early next year.
Over time, the same technology is likely to be rolled out for various engines across the Volkswagen Group. Similar systems are already available for the new Audi S6, S7 Sportback and S8.