· THE STORY
Recovering what engines throw away
In 2014 Formula 1 rebuilt the engine as a “power unit”: a small turbo V6 joined by two electric motor-generators — one harvesting energy from braking, one from the turbocharger itself — feeding a battery. The Mercedes W05 mastered the formula first and utterly: energy that every previous racing car wasted as heat now comes back out as lap time, and these engines convert fuel to work more efficiently than any other piston engine ever built.