"Active cylinder" refers to an individual component of an engine that is currently producing power by burning fuel and generating force to propel a vehicle forward. Full definition
Thanks to the cylinder shut - off (ACT or active cylinder management) used exclusively for this engine, it offers maximum dynamic performance together with maximum fuel efficiency. (topspeed.com)
The four new petrol engines are - 1.4 - litre TSI which generates 122 bhp of power, 1.4 - litre TSI with Active Cylinder technology that generates 145bhp of power, 1.8 - litre TSI that generates 175bhp of power and a 2.0 - litre TSI engine that generates 214bhp of power. (carwale.com)
The more powerful four - cylinder TSI units also come with Active Cylinder Management. (drivemag.com)