German Car Forum

Xtrac Formula 1 Kinetic Energy Recovery System

Recent rule changes in Formula 1 have drawn heavy criticism from some camps for their tendency to clamp down on innovation and technological development, which they see as the heart and soul of the series. Others see the measures as overdue steps to combat the skyrocketing expense and shrinking number of teams. Whichever camp you’re in, you have to like the 2009 addition of Kinetic Energy Recovery Systems (KERS) because it’s a prime example of Formula 1 pushing the boundaries of technology to gain more performance and efficiency, while simultaneously giving the sport a greener (and hence more popular) image. Initially announced in June of 2007, the Xtrac system is being shown this weekend at Autosport International in England.

The KERS system is basically a CVT connected to a flywheel that engages on deceleration, recuperating some of the energy that would otherwise be converted to heat in the brakes. This spins the flywheel up, which continues spinning until called upon to boost acceleration. Under the new rules, which go into effect in 2009, the driver can only use the boost provided by the KERS system for a predetermined amount of time and at an established rate, much like the ‘Push to Pass’ technology in Champ Car World Series racing. This - especially in combination with the lack of traction control - will hopefully help with the difficult overtaking situtation currently plaguing Formula 1.
Although it sounds relatively simple, the actual construction of the KERS unit is a marvel of complexity and compactness. Packing a flywheel and a full CVT transmission capable of withstanding Formula 1 rigors - and transmitting enough torque to meaningfully improve a car’s performance - into a 5kg package, the KERS is also dimensionally compact, an obvious necessity for applications inside the already tiny space of a Formula 1 car. The ‘variator,’ as the CVT portion of the KERS unit is called, operates at over 90 percent mechanical efficiency. The efficiency of the entire unit will remain cloaked for some time, as the flywheels will designed and built by the individual Formula 1 teams themselves.
The other primary benefit to the highly efficient mechanical system is that unlike the energy-storing systems we encounter in road-use cars such as the Prius, there are no batteries involved. No batteries means the drivers are safer, less weight and space are occupied and the KERS system is even more environmentally friendly, since it won’t be made of - or involve the disposal of - highly toxic lithium-based batteries. The system is even being eyed for application in consumer vehicles, since its flywheel-based nature makes it ideal for stop-and-go traffic use.
http://www.motorauthority.com/news/motorsport/xtrac-formula-1-kinetic-energy-recovery-system/