Flybrid Automotive Ltd., a small, innovative and privately-owned
company with a hand-picked team of engineers at Silverstone, UK, has been
working on flywheel-based kinetic energy recovery systems (KERS) for a few
years with leading vehicle- builders, including JaguarLandRover (JLR).
In the case of JLR, the
KERS has been linked to a continuously variable transmission (CVT) activated at
the rear axle. The work has proved particularly beneficial and is now being
extended. Initially commissioned to demonstrate fuel economy gains, the
technology, still using the same basic rear axle mounted flywheel and CVT, is
being directed towards enhancing vehicle performance.
However, at this juncture,
JLR does not appear to have a platform that is design-ready to accept a
flywheel-based KERS. In any case, Jaguar has a number of other vehicle programmes
it is anxious to bring to market more quickly.
In the case of Volvo however,
it appears that Flybrid Automotive entered the scene at just the moment the
Swedish company was designing a new platform. And its new platform is flywheel-ready
and could be introduced with a couple of years.
‘It is suitable for our technology
and could be launched around the end of 2016,’ notes Tobias Knichel, Flybrid Automotive’s
commercial manager.
Although Knichel is
unwilling to be drawn further, it is not unreasonable to surmise that Volvo
could introduce KERS as a performance-enhancing feature in a vehicle (as this
is one area where KERS has been demonstrated to offer impressive gains) before
being offered to improve fuel economy. On the other hand, KERS could be used as
part of Volvo’s downsizing programme.
‘All those we have worked
with are open to the technology and keen to investigate and learn,’ added
Knichel.
The road-car application is
one of a number of areas where Flybrid Automotive is seeking to apply
flywheel-based KERS. Others include motorsport, off-highway and urban bus and
truck. But of these the first production application of a flywheel hybrid is
likely to appear in the Wrightbus StreetLite product range by 2014.
Breakthrough
This marks a breakthrough for Flybrid Automotive which has pioneered the application of mechanical flywheel KERS using either the clutched flywheel transmission (CFT) or the continuously variable transmission (CVT) of the type developed by Torotrak (Development) Ltd. of Leyland, Lancs, UK.
As well as Wrightbus,
Flybrid Automotive is working with Productiv, transmission maker Voith Turbo
and bus operator Arriva. It is a unique opportunity for Flybrid Automotive to
demonstrate the technology as Wrightbus and Voith both have European customers.
The final choice has yet to
be made as whether the Wrightbus application will adopt CFT or CVT. It is
understood that Flybrid Automotive, as systems integrator, will be largely responsible
for the choice.
‘That is why it is
important to see that Wrightbus is fully up to speed and into production. That
is our first target,’ confirmed Knichel.
A prototype vehicle fitted
with KERS will undergo extensive testing at the Millbrook Proving Ground in
Bedfordshire (currently up for sale), with in-service trials with leading
operating partner Arriva also scheduled as part of the project.
The aim is to make
Flybrid-powered StreetLites available from 2014 onwards, both for new vehicles
and as well as an upgrade in buses already in service.
The Flybrid Automotive
project is part-funded through the Low Carbon Innovation Platform (LCVIP) scheme
managed by the Technology Strategy Board (TSB), itself sponsored by the UK
Department for Business, Innovation and Skills. The TSB has provided funding of
£700,000 for this project, match funded by the project partners in a total
project investment of £1,400,000.
Manufacture
The small Silverstone-based company aims to manufacture its units in-house and is currently assessing the best route to take to achieve this. More than likely it will expand its manufacturing facilities and increase it staff complement.
Flybrid Automotive employs
about 20 people and has a turnover of around £2 million. It is currently
recruiting for more staff.
‘For the volumes we are
looking at for the Wrightbus application, we think we can cope within Flybrid Automotive,’
said Knichel. ‘We are looking at expanding our facilities. It is on our wish
list of how we want to grow. We think the volumes that will be required for the
bus and truck market can be achieved within Flybrid.’
The point at which Flybrid
Automotive expands its facilities, both in terms of testing, machining and
assembly to accomplish the requirements is one that has to be finely judged.
Timing is critical.
Should a road-car
application come along as the Wrightbus programme gathers momentum, though extremely
welcome, will nonetheless pose additional challenges.
Meanwhile, the urban bus
application, with its stop-start duties, could provide valuable information for
another possible area of application, namely commercial vehicles used for urban
delivery duty cycles. In this respect, test results from the Millbrook experience
will be invaluable.
However, according to
Knichel, truck applications of flywheel hybrids are likely to appear after
urban bus and off-highway applications.
Knichel claims that off-highway
duty offers the same level of timing as the urban bus application. Dump truck
and shovel loaders could each use a flywheel-based KERS as a power boost power
with a smaller-sized engine, or to achieve fuel economy gains.
However, all three –
off-highway, bus and truck – are quite similar in terms of flywheel hybrid
requirements and how quickly they can enter production and appear in the market.
Road-car applications are seen as being longer term; they can take longer to
evolve as more people (in product planning and manufacture) are involved in
decision-making.
Motorsport applications, as
Flybrid Automotive has proved, can move fastest of all from design, through manufacturing
to on-road experience.
The city car application,
in theory can offer huge potential for the relatively simple CFT transmission.
A three-clutch CFT linked to a two-ratio range extender would generate a ratio
width of six. At the other end of the range, for example in a luxury car, a seven-speed
gearbox linked to a three-clutch CFT could generate 21 ratios – while a four-clutch
CFT would generate 28.
Flywheel hybrid engineers
claim a CFT offers a more flexible design and manufacturing solution than a CVT;
for example when scaling up it can use four clutch packs instead of three. Also
a CFT uses widely known and understood technology and components, and it has no
requirement for special and expensive lubricants. ∎
