Volkswagen are set to introduce their next piece of technology in the never-ending fight to make their engines greener. From 2012 their 1.4-litre TSI engine will feature cylinder shut-off, a first in a high-volume production four-cylinder engine.
In simple terms this technology aims to make the engine more efficient by shutting off two of the four cylinders when the engine is working under a light load. In this mode Volkswagen are claiming reductions of up to 0.4 litres per 100km on the European average cycle while the greatest gains are available at around 30mph. At this speed the improvement is almost 1 litre per 100km, a saving of just under 20% on the current 1.4 TSI Polo GTI (if my maths are anywhere near correct).
Cylinder shut-off is active whenever the engine revs are between 1,400 and 4,000 rpm and the torque output is between 25 and 75 Nm, conditions that match nearly 70 per cent of the EU fuel economy driving cycle. As soon as you squeeze the pedal hard enough cylinders 2 and 3 come back to life instantly. The system takes its information from the accelerator pedal sensor and will adapt to driving styles, so if you fancy a full-throttle blast down your favourite road the system will remain switched off until you return to ‘normal’ conditions.
So why should we care about this pandering to the eco-mentalists? Because it means that you can have your cake and eat it. In normal driving conditions the engine is even more fuel-efficient than the outgoing twin-charged 1.4 TSI but when you want some fun all four cylinders come back online and you get the full-fat experience. Road tax will be cheaper too thanks to the lower CO2 figures, and Volkswagen promise that driving refinement will be unaffected in two-cylinder mode. Sounds like progress to me.