how does this work...anyone have any ideas?

Cien features the new Northstar XV12, a 7.5-liter dual-overhead cam (DOHC) engine that generates an amazing 750 horsepower and 450 ft-lbs of torque. Advanced features include GM's Displacement on Demand technology, which allows the engine to run seamlessly on six cylinders at times to maximize fuel savings, plus a direct injection gasoline combustion system for increased engine power, and a combined starter generator.