System addicts

To stay relevant and command the large investments needed to keep itself at the cutting edge of technology, motorsport has to stay somewhat relevant to the mainstream, road car-based automotive industry.

More and more, electric powertrains are being incorporated into high-level racing. Formula 1 was ahead of the curve in 2009 with its hybrid Kinetic Energy Recovery System (KERS), while in 2012 Audi led the way in the Sportscar world with the R18 e-tron Quattro LMP1 platform with its diesel-electric hybrid powertrain.

More recently, Formula E launched in 2014 as the first full-electric race series backed by the FIA and, with the recent announcement of the Electric GT series planned for 2023, seemingly the industry is not looking back.

In hybrid systems, the working concept is clear – incorporate an electrical element to the powertrain to augment the output of the internal combustion engine (ICE). The intent is not just to ‘add on’ power to the IC engine in the same way as something like turbocharging, it’s intended to increase the efficiency of the vehicle, capturing kinetic energy that would otherwise be wasted as heat through the friction braking system and using that to drive electric motors. The result is a decrease in fuel consumption over the duration of a race.

Close competition

With hybrid prototypes competing against non-hybrids in the World Endurance Championship and Le Mans, regulations generally stipulate a similar maximum energy output across the grid to ensure the championship remains competitive. Logically, hybrids have downsized engine capacity relative to non-hybrids due to this.

From a performance point of view, the penalty incurred through the additional weight of the system is offset by traction advantages and reduced fuel consumption over a stint, meaning fewer fuelling stops. There is certainly an inherent performance advantage to using the technology, so in practice Equivalence of Technology (EoT) balancing is used to keep non-hybrids and hybrids competitive.

Hybrid boosting is achieved with different configurations, but, so far, motorsport has always been a parallel arrangement in which the electric motor, ICE or both have the capacity to supply torque to the wheels at any moment.

In LMP1 platforms such as the R18, the electrical system supplied and harvested energy from the front wheels only. Combined with the ICE, this created a 4WD system, which had obvious benefits to traction at corner