gearbox and the logical way to do that is
with a continuously variable transmis-
sion (CVT). You need a speed range of
about 6:1 and by happy coincidence a
Torotrak toroidal CVT is about 6:1.’
The other key element of the system,
developed by the Silverstone-based
project leader Flybrid Systems, is the
flywheel itself. Featuring a specially-
designed hermetic seal that runs at 64,000
rpm and a containment system that
addresses the safety concerns associated
with running a flywheel at high-speeds,
its developer claims that it represents a
fundamental breakthrough in the devel-
opment of mechanical KERS systems.
‘Our flywheel runs at least three times
faster than any previously known
vehicle-mounted example,’ claimed Fly-
brid’s Jon Hilton. ‘This makes it nine
times smaller and lighter which reduces
the size of our hybrid system enormously
and gets us to a position where it could
almost be considered an accessory.’
Designed to be activated manually by
F1 drivers, Moore said the system could
be deployed in a number of ways. ‘You
can’t use it until you’re doing 100kph, but
you could deploy it once you’ve reached
that speed meaning you end up with a
potential gain of several metres by the
first corner. You could use it to improve
your maximum velocity on the fastest
part of the circuit — on some you could
end up with a 20m or 30m gain by the end
of the straight. You could use it as an
overtaking tool or to prevent people from
overtaking you.’
But while Moore and the rest of the
team are keen to explore other opportuni-
ties for their system in motorsport (Le
Mans, for example, with its numerous cor-
ners looks set to really benefit from
KERS) the big potential for the technology
is to make road cars and other vehicles
more fuel efficient. ‘Motorsport provides a
way of demonstrating that the technology
is completely viable,’ said Moore.
Indeed, thanks partly to the rigorous
challenges of designing a device for F1,
Moore believes that the group’s fully
mechanical system could have distinct
advantages over the electrical hybrid
solutions that are already on the road.
‘There’s a very big efficiency advan-
tage because it’s mechanical,’ he said.
‘Obviously there are some mechanical
losses, but the wheel-to-wheel efficiency
is much higher than it is for electrical
systems; you could be talking a 70 per
cent-plus efficiency level, whereas electri-
cal systems, which convert energy from
kinetic energy into electrical energy,
chemical energy and ultimately back in
to kinetic energy are down in the 30s.’
And it looks like we may be seeing
flywheel-enabled hybrids on the roads
‘The wheel-to-wheel efficiency is much higher
than it is for electrical systems which convert
kinetic into electrical energy’ Jon Hilton, Flybrid
sooner rather than later. Hilton said he
is engaged in vehicle discussions with a
number of road car OEMS, while
Moore claimed that the technology is
likely to appear on a production
prototype within the next three years.
Moore suggested that one way the
device may be applied to road cars is as
a bolt-on complement to existing elec-
trical systems. ‘There are some advan-
the EnGIneeR 21 APRIL–4 MAY 2008 31
tages to using an electrical system and
then a mechanical one for bursts of
power if you suddenly want some accel-
eration,’ he said.
But unlike the F1 application, the
consumer version of KERS is unlikely
to feature a ‘big red button’. ‘You would
have no driver input at all,’ said Moore.
‘The driver will just drive the car and if
he requests a certain acceleration mode
via the throttle the car would work out
whether you do it by battery or
whether you use some of the flywheel
energy you have recovered.’
Straying even further from the
world of motorsport, Moore said that
the system could even help boost the
efficiency of public transport. Trains,
which have a highly structured start
and stop cycle are ripe for a KERS
device while buses, somewhat
ironically given their lumbering
nature, have a very similar duty cycle
to an F1 car.
‘An F1 car goes through a corner
very slowly and then accelerates very
quickly down the straight and slows
again and accelerates and stops every
now and then for a pit stop.
That’s pretty much what a bus does, ’
joked Moore.
INSIGHT
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