The Flybrid kinetic energy recovery system (KERS) stores energy more efficiently than battery system

"with a flywheel each time the brakes are applied at least 65 per cent of the energy is available to re-accelerate the vehicle, whereas the best that can be achieved with existing battery technology is 45 per cent."


http://www.greencarcongress.com/2007/10/flybrid-flywhee.html

The Flybrid kinetic energy recovery system (KERS) incorporates Continuously Variable Transmission (CVT) technology sourced from the partnership of Torotrak Plc and Xtrac. Xtrac is using Torotrak’s full-toroidal traction drive technology for use in kinetic energy recovery systems within the motorsport industry. (Earlier post.) The FIA have defined the amount of energy recovery for the 2009 season as 400kJ per lap giving the driver an extra 80hp over a period of 6.67 seconds.

The mechanical KERS system uses flywheel technology developed by Flybrid Systems to recover and store a moving vehicle’s kinetic energy which is otherwise wasted when the vehicle is decelerated. The combination of gearbox-variator and flywheel form part of the driveline assembly. Energy is received from the driveline through the Torotrak CVT as the vehicle decelerates, and is subsequently released back into the driveline, again through the CVT, as the vehicle accelerates.

Compared to the alternative of electrical-battery systems, the mechanical KERS system provides a more compact, efficient, lighter and environmentally-friendly solution.

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On a directly comparable basis, a flywheel system offers up to twice the efficiency of a kinetic energy recovery system that stores its energy in a battery. The overall in-out efficiency of a mechanical drivetrain feeding energy into a flywheel and back out to the vehicle again via an ancillary transmission system is approximately 65-70 per cent compared with 35-45 per cent for a hybrid battery-electric system. Fundamentally, this is because a purely mechanical system doesn’t have to convert the kinetic energy into electrical and chemical energy as with a battery system.

What this means is that with a flywheel each time the brakes are applied at least 65 per cent of the energy is available to re-accelerate the vehicle, whereas the best that can be achieved with existing battery technology is 45 per cent.

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This is good for stop and go driving but for more extended demands for energy, obviously the battery is better. But for largley city stop and go driving this is an interesting technology.

attached to the brakes, and a hydrogen engine.

I think it ran around Frankfurt for a few years while they worked out the kinks. At the time, it ended up being far too complicated to actually put into production.

It's about time for it to come back. These wishful thinking exercises never really die; but they do take vacations.

of pro-nuke hype around here though ;-)
:rofl:

that a topic as important as Energy and Environment is open so many people whose most sophisticated response to important issues consist of internet giggly smileys.

In general the number of giggles so posted are most commonly found with the highest distribution among those who, having never opened a science book in their lives, do not now how to frame a scientific question, respond to one, or perform even the simplest task in analysis.

When they're not posting giggles, they're posting stuff put in the news by reporters who approach their own level of confusion, or else repeating verbatim some marketing hype they've heard on some advertising show or seen on some advertising writing.

I can't say I enjoy these people exactly - and in fact I hold them more or less responsible for the 390 ppm we're at right now with dangerous fossil fuel waste.

But it is probably a good thing that they do things like come to the internet to display their puerile obliviousness so that it can be exposed for what it is.

It is not fine to accept ignorance or tolerate. Ignorance must be shown for what it is, because ignorance is not neutral, not benign. On the contrary, ignorance kills.

...less dense than conventional liquid fuels (gasoline, ethanol), etc.

It would be nice to see flywheel efficiency get better though (build them of carbon nanotubes, would be orders of magnitudes more powerful).

Still the niggling problem of a car accident rupturing the flywheel storage device.