ACT is active over an engine speed range between 1,400 and 4,000 rpm and torque outputs between 25 and approx. 100 Nm – a range that covers nearly 70 per cent of all driving states in the EU driving cycle! If the driver presses the accelerator pedal hard, both cylinders begin to work again without a noticeable transition. The high efficiency of the system has no negative effects on smooth running: even with two cylinders the excellently balanced the 1.4 TSI engine of the Polo BlueGT runs very quietly and with low vibration.

All mechanical switchover processes take place within one-half of a camshaft rotation; depending on engine speed this takes between just 13 and 36 milliseconds. Accompanying interventions in ignition and throttle valve processes smooth the transitions. What’s more, thanks to an accelerator pedal sensor and intelligent monitoring software, the system can also detect irregular driving profiles – such as during a drive through a roundabout or in sporty shifting on a highway. In such cases, cylinder shut-off is deactivated. The driver is aware of whether two or four cylinders are active by a related indicator in the multifunction display between the speedometer and tachometer.

Article source: www.volkswagen.co.uk