Green issues are as important in motorsport as they are in the wider motor industry. For 2009, Formula 1 will introduce new rules aimed at improving environmental performance in the sport.

These include a system to recover the energy lost in braking and deceleration, store it and then use it when it's needed for acceleration.

These are the same basic principals that hybrid cars use, where deceleration energy is converted into electrical energy, stored in batteries and then used to drive a motor to help propel the car when accelerating. But they are not without problems. 

Each time energy is converted into another form, there's a loss in efficiency and hybrids convert movement (kinetic) energy into electrical energy, then chemical energy in the batteries, before converting it back to electrical, then kinetic energy again.

In addition, the batteries are difficult to recycle because of the toxic metals they contain and the system adds the weight of the batteries, electric motor and control systems to a conventional car.

Torotrak and Xtrac have come up with a far simpler solution for Formula 1. A flywheel can store kinetic energy directly. It works like a child's spinning top. Spin it and it will keep spinning for a very long time. It can also be a source of energy by feeding its spinning motion back into another moving system.

Xtrac has a global reputation for building transmission systems for motor sport, while Torotrak has considerable experience of constantly variable transmission systems.

A flywheel is connected to the Xtrac transmission via a Torotrak toroidal traction drive variator. We'll skip the technical details here, the important thing is that it is a simple lightweight automatic transmission that can respond very quickly, either by transmitting power to the flywheel or transmitting it from the flywheel on demand.

Xtrac's chief engineer Martin Halley told us, "The system can convert low speed input of around 1,500rpm to 30,000 or even 60,000rpm at the flywheel." Compared with the 36 per cent efficiency of the electrical based hybrid drive, the Xtrac/Torotrak solution offers around 90 per cent efficiency and can be developed for use on the road. Are the hybrid's days already numbered? 

See also: UK: Torotrak enters F1 technology agreement with Xtrac