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RICARDO QUARTERLYREVIEW
Q2,
200
6Back on trackHas motor racing lost its relevance?
GM’s former sporting chief has answers
ParticulatesRicardo develops revolutionary
measuring technology
Diesel record bidJCB unveils world land speed
contender, supported by Ricardo
BUGATTI VEYRONSPECIALRicardo supports Bugatti to design,develop
and manufacture the driveline forthe Veyron – the world’s fastest
road car
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One thousand and one horsepower, sixteen cylinders, seven speeds
and over400km/h – transmission engineering challenges don’t come
much tougherthan Bugatti’s fabulous million-euro Veyron
supercar.Tony Lewin reports onthe support provided by Ricardo in
the development and manufacture of oneof the most sophisticated
driveline systems ever conceived
“The most advanc e
It’s the front-cover splash of almostevery car magazine in the
world.Everywhere, writers are strugglingto find new superlatives to
describe itsastonishing performance. Andeverywhere the message is
the same:this million-euro machine redefines,dramatically and
decisively, our ideaof what a car can do.
The concept of a road car faster thana Formula One car is no
longer fantasy
but fact; thanks to Bugatti, thisremarkable display is now seen
asachievable with a car that’s alsoelegant, luxurious and refined,
andwhich does not demand racing-driverskills at the wheel.
Bugatti has defied the doubters andproved that 400 km/h and
first-classcomfort can indeed go together. Yetwith expectations so
suddenly and sodramatically transformed, it is all too
easy to forget what a monumentaltechnical achievement the
Veyronrepresents. It is especially important torecall that, at the
time it was originallyproposed in 2000, the idea of the
1001horsepower sports car seemed a nigh-on impossible technical
challenge.
VW chief astounds the industryA moment of stunned silence
grippedthe audience of international
Bugatti Veyron
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-
ed car of our time”automotive journalists as the crowd
ofnormally talkative reporters choked indisbelief at what they had
just heard.The scene was the Nogaro HiltonHotel in Geneva in March
2000, whencorrespondents had assembled tohear Volkswagen’s then
CEO, DrFerdinand Piëch, deliver his annualstate-of-the-union
address to theworld’s business and technical media:in the middle of
a long stream ofcorporate results, sales predictionsand bland
technical statistics, Dr Piëchhad casually tossed in the
numberwhich was to astound everyone – onethousand and one
horsepower.
For this, said Dr Piëch, would be thepower output of the new
BugattiVeyron sports car. Only the absoluteultimate in power,
performance andsophistication would suffice for the
21st century revival of what had in itsheyday been the most
glamorousmarque in the world. “This will be themost exciting and
most advanced carof its time, no more, no less,” hepredicted.
Previously, only a select few racingcars had breached the
thousand-horsepower mark. It would clearly be amajor technical
challenge to feed thispower to the road safely enough fordrivers
with standard rather thancompetition licences: delivering
suchstupendous performance with thesmoothness and refinement
demandedby an elite millionaire clientele waslikely to be a bigger
issue still.
Bugatti’s HeritageIt is difficult from today’s perspectiveto
imagine the awe in which the
Bugatti marque was held during its1920s and 1930s golden age.
Its sportsand racing cars were engineered withabsolute purity of
focus, always light,ingenious and elegant; the integrity ofthe
road-car chassis attracted the verybest coachwork builders of the
era,producing style landmarks such as theAtlantique coupé and, at
the oppositeend of the scale, the mammoth Type41 Royale. In its
exotic aura Bugattiwas the Ferrari of its time, but with
theequivalent of Rolls-Royce luxury,radical thinking from Lotus and
hard-wired race heritage from McLarenthrown in too.
Undeniably, the task ofreinterpreting this unmatched legendfor
the 21st century customer hasbeen a daunting one.
Accordingly,Volkswagen decided to call upon the
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1250 Nm of torque, but also forautomated shifting and
electro-hydraulic control of all key functions.The driveline, too,
was to be ofexceptional complexity, with drive toall four wheels,
an innovative activerear axle, a Haldex coupling built intothe
front axle, and all the electronicand hydraulic control systems
to
determine not just straightline tractionbut high speed vehicle
dynamics too.
What at the beginning was simplyan outrageously fast pure sports
carsoon found itself doing double duty as
10 RICARDO QUARTERLY REVIEW • Q2, 2006
Bugatti Veyron
very best skills on offer among theworld’s automotive
engineeringproviders to ensure the born-againBugatti would satisfy
theextremely high demandsplaced on it by customerswhose
automotiveportfolios already includethe likes of Bentley,Ferrari,
Porsche andMercedes-Benz.
For the embryo Bugattidivision, set up underVolkswagen’s
Wolfsburgroof pending thecompletion of the BugattiAtelier at the
marque’sfamous Molsheim homeacross the border in France,Ricardo was
the natural choiceof engineering partner for thetransmission and
driveline system.
Michael Kodra, Bugatti engineer incharge of the liaison with
Ricardothroughout the programme, explains:
“We had already worked withRicardo on smaller programmes –
theybuilt the axles for two different showcars that were presented,
and theseaxles worked perfectly and without anyfurther problems. We
also needed acompany which could supply us with agearbox at low
volume: most of theother big gearbox suppliers are seekingto make
money through volumes, andwe can only offer a run of about
300.Thanks to this and our previousexperience with them on the W18
andW12 sports car, we decided thatRicardo would be the best company
tosupport us on this job.”
Ricardo’s biggest-ever drivelineprogrammeThough Ricardo enjoys
anunparalleled reputation in the field ofultra high performance
transmissionsystems across both sports and racingcars (providing
drivelines for theJaguar XJ220, McLaren F1 and Audi’sLe Mans
winners, for example), oncethe specification of the Veyron
wasrevealed it soon became clear that theBugatti transmission
system would bemuch the most sophisticated thecompany had ever
built. As a result,the programme would be the largestever supported
by the company’sdriveline and transmission engineers.
Bugatti’s brief called not just for aseven-speed dual clutch
gearboxcapable of handling an unprecedented
With seven speeds, dual clutches, four wheel drive and an active
rear axle,the Veyron driveline (right) is one of the most complex
ever bulit
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a much moreluxurious, more
Bentley-like vehicle –while of course retaining
all its daunting performancerequirements. Attaining all
these demanding design goals,many of which would
conventionally be seen as totallyincompatible, was a major
achievement by Bugatti and all the
companiessupporting theVeyronprogramme.Yet, at thesame time,the
fact thatthe Veyron
programmebecame part of
the mainstreamVolkswagen
product developmentprocess provided what
was to be the most challengingtask of all.By bringing the Veyron
‘in-house’,
Bugatti’s new technical director, Dr Wolfgang Schreiber, ensured
thewhole vehicle met the same dauntingdurability targets that would
normallybe fulfilled by standard million-a-yearGolf-platform family
cars – modelswhich have to perform faultlessly inservice over many
years of hard use.Prior to the arrival of the Veyron, thenormal
life expectancy for a raresupercar was frighteningly short,
withnumerous pit-stops and replacementsystems required at frequent
intervals.What Schreiber prescribed wasmassively more demanding
than
Q2, 2006 • RICARDO QUARTERLY REVIEW 11
anything ever seen among normallyfragile supercars.
The durability requirements maketruly terrifying reading for
anyengineer with an ounce of mechanicalsympathy. Given that much of
its50,000 km is driven with thethousand-horsepower engine at
fullthrottle, the Veyron’s transmissiondurability programme must
rate asone of the toughest the auto industryhas ever devised.
Mike Everitt, senior programmesmanager at Ricardo, believes that
thisregime makes the Veyron thestrongest ultra high performance
carever built. “Wolfgang Schreiber hasgenuinely shifted the
goalposts in thesupercar segment,” he says.
Big-name supercars all too oftenprove fragile in service. It is
rumouredthat one model is only capable ofdoing three full-bore
launches beforethe clutch needs to be replaced. TheVeyron, on the
other hand, completed200 consecutive full-throttle launcheswith
consummate ease. “The testersonly stopped because it was gettingtoo
dark,” remembers Everitt. “Theclutches were still fine.”
“When exposed to the full 1,250 Newton-metres torque of the
16-cylinder engine, the resistance of the air and even the force
ofgravity itself seem to have no chance: the EB 16·4 Veyron eats
upthe road as if these physical laws had just been abolished”
Bugatti publicity, 2003
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brings home the scale of the multi-national Ricardo and Bugatti
drivelineteam’s achievement. There are nofewer than 660 part
numbers for thedriveline’s 1200 components and thesystem breaks new
engineeringground – particularly in its use ofseven forward speeds
and twinclutches, and in its real-time role indetermining high
speed vehicledynamics through its active reardifferential and
Haldex coupling.
The use of ADAMS simulationmodelling of vehicle dynamicsallowed
Ricardo to provide Bugattiwith much necessary data to developand
optimise suspension kinematics,to fine-tune the car’s
drivingcharacteristics and present a range ofoptions to Bugatti
management.
“Bugatti engineers determined whatthe preferred calibration was
to be,”says Mike Everitt. “They have beenhighly successful in
calibrating the carin precisely the desired manner, withour
assistance. We have helped themgive the Veyron the character
theywere looking for.”
Driving the VeyronAs a key figure in the Veyrondevelopment
process, Mike Everittwas familiar with the astonishingabilities of
the 16-cylinder Bugatti longbefore the international press
wasfinally allowed access to the car inSicily in October 2005.
While the assembledcorrespondents were excited, effusiveand
often emotional in theircomments, Everitt retains the level-headed
detachment of an engineerprofessionally reviewing a
technicalmission successfully accomplished.
Complex though the transmissionhardware undoubtedly is, he says,
the
“
”
MICHAELKODRA Michael Kodra isthe Volkswagengroup engineer
incharge of liaisonwith Ricardo andother key suppliers
Did the experience with Ricardogearboxes on the Audi Le
Manswinners influence your choice ofdriveline partner?No. We
started this programme justbefore the Audi programme becamepublic.
Ricardo always keeps itsother customers secret, so even weat VW did
not know that this workhad been done for Audi in the racecars.
The driveline for this car is verycomplicated and has a huge
effecton the handling and drivingcharacteristics of the whole
vehicle.How is it that VW can work togetherwith an outside supplier
when it isreally determining how that vehiclewill drive?Using the
knowledge we havegained through working withRicardo we have
implemented thecorrect features into the car, such asthe rear axle
differential, theelectronic/hydraulic control, theHaldex coupling
which enables us tohave four wheel drive, and this dualclutch
gearbox. We have been verysuccessful in learning how tocalibrate
and to optimize them.
What about the active reardifferential?At that time the rear
differentialcontrol was something VW hadnever had in its ordinary
cars: wewere about to introduce it in theTouareg luxury SUV. This
isdefinitely an item where weneeded to have a close look andliaise
with these [Ricardo] guys in their work. On the gearbox side, we
have done the same gearbox, though much smaller and lighter, for
our ordinary passenger ranges such as the Golf. Here, Ricardo
learned from VW concerning some software strategies and so on. So I
think we both share a little bit, we both learn a little bit.
12 RICARDO QUARTERLY REVIEW • Q2, 2006
Bugatti Veyron
Design, development andmanufactureThe complexity of the
driveline and itscontrol system was such that MikeEveritt and his
colleagues at bothRicardo and Bugatti had to bring inextra
engineers to ensure theprogramme would keep to the verydemanding
schedule set by Bugatti: atits peak, Bugatti’s engineering teamwere
supported in the programme byover 50 Ricardo driveline
andtransmission engineers, with a further12 -15 electronics
specialists workingon the transmission control systemand additional
engineers in vehicleengineering too. Two Ricardoengineers even took
up residence inVW’s home city of Wolfsburg.
“One mustn’t forget the absoluteenormity of the task that
facedBugatti,” explains Everitt. “It designeda car that’s not only
the fastest andfastest-accelerating car in the world,but one which
is technically far moreadvanced than any of itspredecessors.
“It has far more features in it,”continues Everitt. “It’s
four-wheeldrive, it is turbocharged, it has anactive differential
and an active drivetransmission system with dualclutches. The car
is very sophisticatedand is entirely new: new engine, newdriveline,
new chassis, new everything– and it’s attacking the market as
themost prestigious sports car ever built.It has been a very
formidablechallenge.”
Even a quick glance at the cutawayof the Veyron driveline on
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key throughout is the software thatcontrols it – even though the
driver isunlikely ever to sense it doing its job.
Yet even Everitt cannot resistbeaming broadly as he revels in
theexperience of driving the sixteen-cylinder, 400 km/h
machine:
“If you are driving the car you justpull a lever and all you see
or sense(of the gearshifts) is that the revcounter needle falls or
rises: it is slickand smooth but in the backgroundthere are a dozen
valves controllingkey parameters, changing clutchpressures,
shifting which gear isengaged and which is the next pre-
selected gear and so on.”One of the key challenges of the
gearbox is that it has, on VW’sinsistence, a non-interlocked
gearselection system. This enables super-fast shifts but, in
contrast toconventional gearboxes where it isphysically only
possible to engage onegear at a time, the mechanicalarrangement of
the Veyron box makesit theoretically possible to engage upto four
gears at once. It is a vital taskof the control software to ensure
thatsuch a damaging occurrence cannever happen, and to this end
Ricardospecified twin control networks, eachrunning on different
software codes,written by different teams usingdifferent
methodologies. The task ofthe first is to control the
transmission,
R icardo is no stranger to low-volume, high precision
transmissionmanufacture: its workshops have witnessed the assembly
not only of thedrivelines for the McLaren F1, Jaguar XJ220 and
Volkswagen W12 Nardo recordbreaker, but also five years of Le Mans
winners for Audi and numerous othersuccessful but less well known
products. Even so, such is the importance ofBugatti and the
complexity of its driveline that a whole separate area of
theRicardo transmissions facility is dedicated exclusively to the
assembly of theVeyron system.
Conditions in the Bugatti assembly area are akin to those of a
scientific cleanroom, with each of the driveline’s 1200 components
receiving a three-stagecleaning process – culminating in an
ultrasonic phase – before assembly.Component tolerances are close
to aerospace levels at 6-8 microns, and exoticmaterials include
rare-earth magnets located on the gear selector forks forextremely
precise position sensors mounted on the external casing to
monitorthe exact location of selectors. This information is used in
the control strategyand helps rule out double gear engagements.
“This is a very high quality, and clearly very high cost
operation,” says AdrianTurner, manager of Ricardo’s low volume
production operation, of themanufacturing process. “It’s more akin
to an advanced prototype build thanseries production – we call it
dedicated cell manufacture.”
The cell system sees two technicians each assemble a single
transmission aweek. Each stage of the assembly process is
meticulously documented, withthe technician confirming every
operation, measuring every tolerance andcritical dimension and
noting the thicknesses and positions of all shimsemployed. The
multi-page document is held in the Ricardo database so that
anyin-service problems can be traced back to individual parts of
known history.
while the second continuouslymonitors it to double check that
adouble engagement is not about totake place.
Surprising though it may seem for acar of such phenomenal
performance,the concept of everything workingfaultlessly and
seamlessly in thebackground is an important part of theBugatti’s
make-up – again making apotent contrast to supercarcompetitors
which can be famouslytemperamental and tricky to drive.
Mike Everitt describes it as silkysmooth and easy. “When the
caraccelerates it is so fast that if you havea clear road in front
of you and youcan accelerate up to 150 mph (240km/h) – which it
will do in a matter of afew seconds – it will be up to fourth
orfifth gear and you really didn’t evencount them.
“If you are not watching the geardisplay change or watching the
revcounter needle change, if you’re justlooking at the road and get
to 150 mphand back off, you won’t actually knowwhat gear you were
in because it doesit so smoothly,” he enthuses. “Even ifyou were in
manual mode, if you don’tdo anything the transmission will shiftup
for you anyway when you reachmaximum revs.”
Step-change for VW engineeringFrom the customer side, VW
liaisonengineer Michael Kodra is open inacknowledging that
Ricardo’s expertisehas been invaluable:
“I think that by being able to bringthis car to the market with
its drivingbehaviour every bit as [good as] weexpected it to be, we
have done a verygood job. Using the knowledge wehave gained we have
implemented thecorrect features into the car, such asthe rear axle
differential, theelectronic/hydraulic control, theHaldex coupling
which enables ushave four wheel drive, and this dualclutch gearbox.
We have beensuccessful in achieving a goodcalibration and
optimisation of them.”
“The toughest part in mostprogrammes is always the
timing,”explains Kodra. “Right from thebeginning of this job we had
a verytight timetable to get this car intoseries production. You
need toremember that almost all thecomponents of the car are brand
new– the monocoque and suspension, acomplete new engine, gearbox
andaxles – all the systems have neverplayed together in one car. We
had thistimetable because the car was
MANUFACTURING THE VEYRON DCT
Q2, 2006 • RICARDO QUARTERLY REVIEW 13
Left: Complex seven-speed dual clutch gearboxtakes one week to
assemble at Ricardo’sprecision manufacturing facility
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Zothecas conubium santet lascivius fiduciasuis. Pessimus
utilitas cathedras spinosus
presented quite early on, but as aprototype car.”
Such striving for engineeringperfection is of course precisely
whatthe Bugatti marque stands for. MikeEveritt cites the example of
thesignificantly raised durabilityrequirements applied from
2004onwards: new gear tooth designswere employed to ensure they
couldnot only last the distance, but alsomaintain the level of
expectedrefinement at the end of the 50,000 kmdurability test. The
new gears solvedthat issue conclusively.
"Nothing is too beautiful, nothing istoo expensive"It was with
this idealistic maxim that,almost a century ago, Ettore
Bugattifounded the company that, like nonebefore and precious few
since, wasdedicated to absolute purity in designand perfection in
every detail. And,though in 2006 the stakes are vastlyhigher and
the regulations governingautomobiles are infinitely stricter,there
can be little doubt that the re-incarnated Bugatti has produced
a
“
”
MIKEEVERITTChiefprogrammesengineer MikeEveritt led thework on
theVeyron driveline since joiningRicardo in November 2000
Ricardo has a lot of experience in highperformance
transmissions. Can youbuild on designs you have done in thepast, or
does it have to be completelynew? You have to visualize the project
astwo distinct elements, the first beingmechanical and the second
thecontrol. For both elements we workedvery closely with the
VW/Bugattiengineering team to ensure both thatthey got what they
wanted and thatwe could incorporate their knowledgeof specific
lessons learned from theirown DCT programme in the VW Golfinto the
programme. In terms of the mechanical side it is tosome extent an
analytical andformulaic process, but it is heavilyinfluenced by the
experience basethat Ricardo and the VW/Bugattiengineering teams
possess. Knowinghow the transmission needs to bedesigned for this
sort of application,with its very demanding andspecialist
environment, is somethingthat few companies have experienceof, but
it is ground on which Ricardofeels comfortable.
The control element of this gearboxwas, however, the really
innovativeside: there are increasing industry andmarket moves
towards dual clutchtransmissions because of the benefitsyou get in
fuel economy andefficiency and driver feel. But to dosomething in
this area ofperformance was quite a challenge:things that work on a
“normal” carsimply don’t just scale up when youget into this class
of vehicle.
When you discuss a programme like thiswith a customer, who sets
out the basicprinciples? Did VW simply want atransmission for a 400
km/h car?No. VW had some quite firm ideas at afeature level –
minimum seven gears,very fast speed of shift and so on. Also,the
fundamental layout options possiblewere largely dictated by the
definedvehicle architecture, but lots of detailswere not defined at
all. This meant forinstance that the gearbox in front and the
rear axle behind the engine was defined,but we explored issues
such as whetherthe rear axle should form part of theengine cylinder
block or should it beseparate.
Did you know the power and torqueoutputs? Did the very high
valuesforce you to think differently?Yes, we knew the power and
torque, butonly as headline numbers, and also thewheelbase and the
predicted weight. Weknew that they wanted it to be fourwheel drive
and that they wanted it to beactive not passive, meaning
activedifferential controls and active torquedistribution from
wheel to wheel. Mostthings about this project forced us tothink
differently.
Is the transmission seven speedbecause with a Vmax of over
400km/h you have to cover such a largespeed range?Yes: it’s also
seven speed becausereverse is in there as well, givingeight gears
in total, with foursynchronizers and two gears persynchronizer – so
that works verynicely. It also gives a nice even gearspacing on a
car that will go seriouslyfast. Another advantage we had withthis
transmission was that we couldmake first gear tall: this car will
do its0-100 km/h dash in first gear.
In terms of the mechanical design ofthe system, is it more like
a racing cartransmission than a road cartransmission?No: I wouldn’t
say it is like a race cartransmission at all, it is like a race
cartransmission in the limited sense thatit uses race car
transmission typematerials and very high grade steelsfor the gears
and shafts. It is fullysynchronized on all gears includingreverse,
and all the gears includingreverse are fully helical rather
thanstraight-cut. The emphasis onsmoothness of shift and
pull-awaycontrol is absolutely key to the wholenature and character
of the car. I think everyone will be amazed at justwhat a pussycat
it can be. You canbumble around at walking pace allday long with
absolutely perfectcontrol: you have no juddering, nokangarooing,
nothing that manysupercars suffer from. It is absolutelythe easiest
car to drive in terms of theclutch and transmission as can beseen
from the many complimentarypress reports of the car.
14 RICARDO QUARTERLY REVIEW • Q2, 2006
Bugatti Veyron
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THE VEYRON IN FIGURES
model of rare distinction and trueengineering integrity – a
model whichdoes genuine justice to the Bugattilegend.
Yet, having designed, developedand built what is pretty
convincinglythe world’s fastest, most powerful andmost exclusive
road car, there is justone cause for regret. No more than300
examples of the Veyron will bebuilt over its production
lifespan;
many will go straight into privatecollections, while the
remainder arecertain to lead a pampered existencein air-conditioned
garages under 24-hour security guard. So, regrettably,only a few
elite individuals worldwidewill ever be able to savour the
uniqueexperience of 16 cylinders, 1001horsepower and the
sensational returnof the most illustrious marque theauto industry
has ever known.
Engine: 8.0 litre W16, four turbochargers
Power: 1001 hp at 6000 rev/minTorque: 1250 Nm at 2500
rev/minTransmission: Ricardo 7-speed
dual clutch; drive to all four wheels
Performance: 0-100 km/h: 2.5 sec0-200 km/h: 7.3 sec0-300 km/h:
16.7 sec
Kerb weight: 1950 kg
Veyron speedometer reads up to 420 km/h;left-hand gauge shows
horsepower deployed
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