When Porsche unveiled the 918 RSR Hybrid Supercar concept, the world was fascinated with the idea of a true performance hybrid.
The 918 uses an electric motor in each of the front wheels. We know what you’re thinking. You probably think that the car runs each of these motors from a battery that is charged by the petrol engine.
Porsche have done something different to the hybrid norm. though.
Like the electric motors on, say, a Prius, the RSR’s can be switched to generators when the car is slowing down.
Where it gets a little different is what Porsche does with the electricity being generated. Instead of sending it into a battery, the system sends it to a third electric motor.
This electric motor has a rotor on the end of it. This is the part that Porsche refer to as the “Hybrid Flywheel”. The “flywheel” is made from a mix of carbonfibre and magnetic materials. So that there is less drag on the rotor, the whole shebang is set inside a vacuum.
The “flywheel” spins at up to 36,000rpm. When the driver of the car presses a button on the steering wheel, the system switches to generator mode and feeds the energy it has accumulated back into the motors on the front wheels.
This provides up to an 8 second burst of extra grunt. Think of it as a road going version of a Champ Car’s push-to-pass.
So, kinetic energy created by slowing the car down is turned into electrical energy via the generating front motors. This electrical energy is then stored as kinetic energy in the spinning “flywheel” and then sent back to the front motors as electrical energy again. The front motors turn the electrical energy back into kinetic energy at the tyres.
This is true storage of energy created by the tyres and then fed back to them, and all without a traditional battery.
It’s all kind of amazing. No doubt someone is working on a regulator for this contraption. So that the energy from the “flywheel” can be fed back into the wheels automatically and regularly, instead of via a button.
Michael Adams from World Car Reviews
Article Originally Written for Infinite-Garage