The Detroit Motor Show in January saw the Porsche 918 RSR Supercar become one of the show-stoppers. Not only does it return supercar performance (0-100 in 3.2 seconds), but it returns consumption figures of only 4.7 liters per 100 km from its hybrid configuration. A truly ‘Green’ supercar.
Now whilst the Detroit Show car was a concept, it could be slated for limited production. The 918 is a performance hybrid with four distinct driving modes and an extra, KERS-type overboost feature like that found on some F1 cars in 2009. It is motivated by various combinations of its 500 plus bhp, 3.4 liter V 8 (derived from the RS Spyder LMP2 car) and two electric motors at the front. This means there is around 700 bhp when required.
Porsche 918 RSR
The move to use the flywheel technology in the 918 RSR to capture energy before reusing it in electric motors that can provide an additional 150kW to the front wheels is a departure from the original 918 Spyder’s hybrid setup that used lithium-ion batteries to store electricity and allow recharging through a regular powerpoint.
Porsche board member for research and design Wolfgang Durheimer says, “The energy for the two electric motors is stored and released by the flywheel accumulator located next to the driver … Charging occurs whenever the driver applies the brakes. At the push of a button the pilot is able to call up the energy stored and use it during accelerate or overtaking maneuvers.”
Unlike the hybrid 918 Spyder, which used lithium-ion batteries to power electric motors for extra motivation, the race ready 918 RSR uses the GT3 R’s flywheel accumulator system that was developed with the Williams F1 team.
The flywheel stores energy from braking, spinning to 36,000rpm and then returning the energy in the form of electricity to electric motors at the front wheels.
Unlike Dr. Porsche’s original “Mixte” over 100 years ago, the electric motors are not ‘in-wheel’, but drive the axles.
However, don’t expect to see one in Thailand, not now, or in the future.