‘Not firing on all cylinders’ is usually an expression used to describe something that is not working as well as it should.
However, in the case of Volkswagen’s forthcoming 1.4TSI petrol engine, it will actually be a fuel-saving feature of the engine. When torque is not required, two of the engine’s four cylinders will shutdown, saving fuel and reducing emissions. The new engine will meet the forthcoming Euro 6 emissions standard.
Volkswagen says that the engine shutdown two cylinders ‘whenever the engine speed of the 1.4-litre TSI is between 1,400 and 4,000 rpm and its torque is between 25 and 75 Nm.’
The largest savings will be when driving at 30mph in third or fourth gear, when fuel consumption will reduce by nearly 1 litre per 100km (62.5 miles). When the driver presses down on the accelerator more firmly, the unused cylinders will be reactivated, which Volkswagen says happens ‘imperceptibly’.
If your are driving in a ‘non uniform’ manner (e.g. in a sporty style), then VW says that cylinder cutoff will be disabled, ensuring that the neither driving experience nor safety will be compromised.
This is not a new idea – it has been in use for some years on certain much larger engines with more cylinders (e.g. large American V8 car engines) – but this is the smallest engine I have heard of receiving this treatment.
For all those who think that a 1.4l engine is pretty feeble to start with and should not be made any slower, remember that the current 1.4TSI engine has both a supercharger and turbocharger and puts out 160PS (158bhp) – as used in the new Tiguan.
You can see the system in action in this video: