In order to limit the size of the recovery systems – and therefore the budgets required to develop them – the ACO and FIA mandated that a maximum 500 kilojoules of energy could be transmitted between two braking phases.

Hybrid cars are therefore permitted to recover energy at the corners where braking is sufficiently heavy to be taken into account. While there were five such zones at Spa-Francorchamps – where Audi’s hybrid made its debut – there will be seven for the 24 Hours.

The Dunlop, Forza Motorsport and Michelin chicanes are among the seven areas/ Michelin, Mulsanne, Indianapolis, Porsche and Ford are the other four zones where hybrids will be permitted to use energy recovery systems.

Audi’s #1 R18 E-Tron Quattro finished second to its non-hybrid R18 Ultra cousin at the 6 Hours of Spa-Francorchamps.