Majestic power
Audi is advancing to the cutting edge of diesel technology
development.
The Ingolstadt brand already has a host of landmark achievements
to its credit – and the list is about to be extended
with the advent of the first ever V12 TDI passenger car
engine. The six-litre unit under the bonnet of the Audi
Q7 V12 TDI study delivers a majestic 368 kW/500 bhp and
a formidable 1,000 Nm of torque. This injects the high-performance
SUV with the dynamism of a powerful sports car.
The colossal power of the Audi Q7 V12 TDI takes it into
a whole new dimension.
A time of 5.5 seconds for the sprint from a standstill
to 100 km/h and an electronically governed top speed of
250 km/h put the performance SUV from Audi on a par with
high-calibre sports cars. The engine limits its consumption
to an average of just 11.9 litres/100 km.
The new V12 TDI is the crowning glory of an engine line-up
brimming with dynamic performance – each and every
one of the diesel engines from Audi generates a high output
and tremendous pulling power for a sporty drive. This
character has emerged over and over again in the brand's
models, not least in the form of the six- and eight-cylinder
2.7 TDI, 3.0 TDI and 4.2 TDI models.
The pioneering role that Audi assumes in the field of
diesel technology stems from the peerless expertise it
has amassed over a period of decades. Since the 1970s,
the Audi engineers have been responsible for one vital
breakthrough after another, the most important being the
world's first ever TDI engine to be fitted in a passenger
car which made its debut in 1989. And in 2008, Audi intends
to start making inroads into the US diesel market with
Bluetec technology: thanks to Bluetec, TDI models bearing
the four-ring emblem are not just sporty and economical,
they can also run so cleanly that they comply with the
emissions legislation in all 50 US states.
A year ago, Audi added yet another new chapter to the
ongoing diesel success story on race tracks around the
world. Developing over 650 bhp, the V12 TDI fitted in
the R10 TDI sports prototype left its petrol-powered rivals
trailing in all of the races it participated in, including
the most challenging of them all, the classic Le Mans
24 Hours. The R10 TDI also triumphed in the LMP1 category
of the American Le Mans Series with an impressive string
of victories.
The V12 TDI – the new flagship
V engine
When working on the road-going version of the V12 TDI,
which will be built in its Györ plant in Hungary,
Audi drew on all of the know-how that underpins the racing
engine. The range-topping diesel is the new flagship model
in the Audi range of V engines, spanning petrol and diesel
units with 6, 8 and 10 cylinders.
The V12 TDI's cylinders actually sweep a greater volume
than the racing engine, which has a capacity of 5.5 litres.
Its 5,934 cc are produced by a bore of 83.0 millimetres
and a stroke of 91.4 mm, the same dimensions as the six-cylinder
3.0 TDI. The two banks of cylinders are positioned opposite
one another with an offset of 17 millimetres. Measuring
just 684 mm long, the V12 diesel has an extremely compact
design. Indeed, its compact size was one of the key prerequisites
for integrating the V12 into the Audi Q7.
The V12 TDI features the same 90 mm spacing between cylinders
as the other models in the V engine series. However, the
cylinder banks are placed at an angle of 60 degrees to
one another instead of the customary 90 degrees. This
particular V12 configuration suppresses all of the inertial
forces and mass moments which would otherwise cause vibrations.
Consequently, the engine's smoothness is flawless in every
regard.
Lightweight construction: crankcase made from vermicular
graphite
The V12 TDI's crankcase is made from a mixture of cast
iron and vermicular graphite – Audi already uses
this high-tech material, known as GJV-450, in the manufacture
of the V6 TDI and V8 TDI. GJV-450, which is produced using
a patented casting method, is around 40 percent more rigid
than cast iron and twice as resistant to fatigue.
This enabled the development team to make the walls thinner,
paving the way for a potential weight-saving of around
15 percent compared to conventional cast iron.
The crankshaft is forged from chrome-molybdenum alloy
steel and is mounted with the aid of an extremely rigid
main bearing bridge made from nodular cast iron. The forged
connecting rods are cracked, and the pistons are made
from aluminium.
The two cylinder heads each comprise three main elements.
The bottom section, incorporating the intake and exhaust
ports and through which the coolant flows, is made from
a low-pressure die-cast aluminium alloy that has a high-strength,
lightweight construction. The top section, which conducts
the oil, is pressure-cast. The cylinder head is crowned
by a reinforcing ladder-type frame which holds the two
camshafts.
Perfect air ducting: flaps in the
intake ducts
The valves are actuated by four camshafts acting via low-friction
roller-type cam followers, the compression ratio is 16.0:1.
The map-controlled swirl variation of the combustion air
deployed in the V6 and V8 TDI models has been retained.
With this system, one of the intake ports for each cylinder
is either opened or closed by means of an electrically
operated flap, depending on the engine's operating point.
Intermediate flap positions are also possible. This allows
the swirl to be adjusted for optimum exhaust emissions
combined with high power delivery.
As is customary on V engines from Audi, the maintenance-free
chain drive is fitted in a space-saving location on the
rear face of the engine. The developers devised a new
layout for the V12 TDI, however. The crankshaft's sprocket
wheel meshes with an intermediate gear which in turn drives
the camshafts by means of two simplex chains. Two additional
chains drive the oil pump as well as both high-pressure
pumps for the common-rail injection system.
2,000 bars of pressure: ground-breaking common-rail technology
The injection technology featured in the V12 TDI is every
bit as revolutionary. The high-pressure pumps both form
part of the common-rail system supplied by system specialist
Bosch. The twin plunger pumps are capable of building
up pressures as high as 2,000 bar in the rails, considerably
more than the previous usual maximum of, at most, 1,600
bar.
The piezoelectric injectors with their eight-hole nozzles
have also undergone a thorough reworking. The tiniest
quantities of diesel fuel are injected into the combustion
chambers through their eight-hole nozzles, whose diameter
has now been reduced to a mere 0.12 milli¬metres.
The high pressure produces an optimum spray pattern inside
the combustion chamber, which makes for a faster, more
homogeneous and, as a result, more acoustically refined
ignition process. What's more, the improved combustion
efficiency increases power output whilst reducing both
fuel consumption and pollutant emissions.
Ultra-fast and ultra-precise: the piezoelectric injectors
The latest generation of inline injectors employs the
piezo effect: piezo crystals expand slightly when an electrical
voltage is applied to them. Over 300 piezo discs are packed
into each of the V12 TDI injectors, which transmit the
minimal expansion to the valve needle directly (inline)
without the need for any form of transmission mechanism
between the two. Each actuation takes just a few milliseconds
– by comparison, a wink of the eye lasts 100 ms.
The fuel pressure and quantity can be adjusted according
to requirements; the number of injection phases per power
stroke can be varied up to a maximum of five with the
piezoelectric technology in the V12 TDI. Main injection
can be accompanied by both pilot and post-injection phases.
Pilot injection lessens the harshness of the combustion
sound, which is particularly noticeable at low engine
loads. The delayed post-injection of fuel serves to increase
the temperature of the exhaust gas – this allows
any particulate residue to be burned off in order to regenerate
the two particulate filters which are included as standard.
Supercharging: a turbocharger for each bank of cylinders
Attached to the outside of the engine's V are the two
turbochargers which each supply compressed air to one
bank of cylinders. Their variable vane geometry ensures
that the full exhaust flow is directed through the turbine
at all times – the turbochargers offer fast response
even at low rev speeds and attain a high degree of efficiency.
Both turbochargers generate up to 2.6 bar of absolute
boost pressure and therefore have a vital role to play
in achieving the formidable peak torque of 1,000 Nm which
the new V12 TDI constantly has on tap between 1,750 rpm
and 3,000 rpm. The diesel's 368 kW/500 bhp equates to
a specific output of 62.0 kW/84.3 bhp per litre.
Cooling effect: two intercoolers to reduce the temperature
of the air
The temperature of the compressed air is reduced by two
large intercoolers. The V12 comes with a double-flow exhaust
system featuring two particulate filters. The intake system
is similarly structured – for each bank of cylinders
there is an air cleaner followed immediately by a hot-film
air mass meter. Two control units operating based on the
master-slave principle orchestrate proceedings inside
the engine.
The Audi Q7 V12 TDI already complies with the Euro 5 emissions
standard, which is due to come into force in mid-2010
and will make especially tough demands in terms of reducing
nitrogen oxides. It was with this in mind that the Audi
engineers devoted particular attention not only to the
new common-rail system and its high-precision fuel metering,
but also to the exhaust gas recirculation system.
At partial throttle, up to 50 percent of the exhaust gases
are fed back into the intake air in order to reduce NOx
emissions. The extensive recirculation system incorporates
a water cooler which reduces the temperature of the exhaust
gases sharply.
The awesome V12 TDI directs its power as standard to a
fast-action, smooth-shifting new six-speed tiptronic transmission.
From here, the forces flow to a quattro driveline, which
splits the drive power 40:60 between the front and rear
wheels under normal driving conditions. This results in
slightly tail-heavy, sporty handling characteristics,
exceptional agility and exemplary steering precision.
To ensure that its phenomenal performance can be safely
harnessed, the Audi Q7 V12 TDI is equipped with powerful,
ventilated disc brakes. The ESP dynamic handling control
system features a hill descent assist as well as a special
off-road mode. The safety specification is rounded off
by the pairs of front, side and head airbags in the interior.
An elaborate double-wishbone independent suspension has
been used for each of the four wheels, while the majority
of the axle components are made from aluminium. The adaptive
air suspension, incorporating an electronically controlled
damper system, comes as standard, creating a perfect synthesis
of sporty handling on the one hand and silky ride comfort
on the other. The body's ride height can be adjusted from
its starting position of 180 mm above the ground up to
the lift mode offering a whole 240 mm of ground clearance.
The Audi Q7 V12 TDI study rides on 20-inch cast aluminium
wheels.
Design: the best of both worlds
The Audi Q7 V12 TDI is just as fascinating to look at
as it is to drive. The principal feature which distinguishes
it from its lesser-powered siblings is the contrasting
paintwork of the underfloor panels at the front and rear.
The striking, almost vertical single-frame radiator grille
has a chromed finish and echoes the dynamic Audi S6 and
Audi S8 models, which both head their respective ranges
powered by V10 FSI engines. Flanking the grille are wide
headlight units with visible light tubes.
The Audi Q7 styling has a thrilling air of elegance blended
with dynamism, and displays both tremendous sportiness
and the robustness of an accomplished off-road vehicle.
The Audi Q7 cuts a powerful, elongated figure, boasting
the sportiest proportions in its segment, with a length
of 5,086 millimetres, a width of 1,983 mm and a height
of 1,737 mm.
The high side panelling gives the vehicle's body a muscular
feel, particularly in the way it contrasts with the flat,
sporty styling of the window area. The dynamic line above
the wheel arches, the powerfully contoured shoulder section
and the flowing roof line combine with the standard-fit
roof rails to emphasise the car's athletic looks. The
distinctive tapering at the front end and the tail with
its steeply angled D-pillars form the end markers of a
distinctly coupé-like silhouette.
The Audi Q7 offers outstanding levels of spaciousness
courtesy of a wheelbase measuring 3,002 mm. The three
rows of seating accommodate up to seven people. The seats
in the second row can be specified with fore-and-aft adjustment
as an option and offer occupants a class-beating footwell
length. Both of the rear rows of seats can be folded down
flat, increasing load capacity to a maximum of 2,035 litres.
The 5-seater version of the Audi Q7 offers 775 litres
of load space in its luggage compartment, while the 6-seater
version features individual second-row seats. The tailgate
of the Audi Q7 V12 TDI opens and closes electrically at
the push of a button.
Amply sized interior plus innovative operating concept
The interior and cockpit area of the Audi Q7 create the
impression of a light and airy expanse, flawless ergonomics
and top quality. The standard-specification deluxe automatic
air conditioning regulates heating and ventilation separately
for the driver's and passenger's side, taking sunlight
levels into account in the process. The Audi Q7 also comes
equipped as standard with the MMI operating system which
has already earned high praise in the A8 and A6 and can
be expanded to include numerous additional functions.
A number of state-of-the-art driver assistance systems
may be specified as an option. These include the radar-assisted
"Audi side assist" for lane-changing manoeuvres,
the "Audi parking system advanced" featuring
both visual and acoustic guidance as well as a rearview
camera, plus the latest-generation automatic proximity
control system, Audi cruise control with braking guard,
which is capable of braking the vehicle to a standstill
if required.
The seats are upholstered in leather, and the front seats
are heated. Carbon panels give added emphasis to the interior's
sporting flair. And to ensure that drivers can enjoy supreme
operating convenience there is a cruise control system,
a driver information system and a multifunction steering
wheel.
Audi already offers the Q7 with a choice of three engines:
the 3.6 FSI has an output of 206 kW/280 bhp, the 4.2 FSI
generates 257 kW/350 bhp and the 3.0 TDI delivers 171
kW/233 bhp. The eight-cylinder 4.2 TDI is due to be added
to the model line-up in mid-2007.
Low-emission TDI engines for the
USA
Green power
The trend towards diesel engines is becoming ever more
pronounced in the United States too. Audi, the inventor
of the modern-day TDI, is going on the offensive in an
effort to bolster this tendency. 2008 will see the arrival
of the Q7 3.0 TDI in US showrooms. Thanks to the exceptionally
low emissions resulting from its cutting-edge Bluetec
technology, this engine is able to meet even the most
stringent emissions limits.
In Europe, diesel-engined cars have been enjoying an inexorable
rise in popularity for years now – in Germany, for
instance, they accounted for over 45 percent of new car
registrations in October 2006. Today's diesel engines
are powerful, fast, efficient, smooth and dependable –
virtues which Audi, in its capacity as a pioneer of diesel
technology since 1989, has been instrumental in achieving.
The diesel market is also beginning to take off in the
USA. In 2006, diesel-powered passenger cars and light
trucks secured a market share of around 3.5 percent, and
this figure is widely predicted to keep on rising. Firmly
convinced that the TDI engine represents the powerful
and economical alternative for the future of motoring,
Audi is seeking to reinforce this trend: the Ingolstadt
brand is embarking on its US diesel initiative.
Strict LEVII standard in California
The stringent legislation governing emissions represents
a key criterion for all passenger car engines in the USA.
The emission standard entitled US Tier II Bin 8, which
is in force in 45 of the 50 US states, limits emissions
of nitrogen oxides (NOx) to 0.20 grams per mile and particulate
emissions to 0.02 g/mile. The LEVII standard, which is
enforced in California and a number of states in the north-east,
goes much further again, restricting emissions of nitrogen
oxides to 0.07 g/mile and particulates to 0.01 g/mile.
The LEVII limits are simply beyond the capabilities of
the emission control technologies required to meet the
current Euro 4 standard in Europe.
This is why Audi has teamed up with Volkswagen and DaimlerChrysler
to develop a revolutionary new technology – it is
called Bluetec and denotes exceptionally clean-running
diesel engines.
The Bluetec technology is built around a dedicated catalytic
converter which goes under the abbreviation of SCR (Selective
Catalytic Reduction) and is positioned downstream from
the oxidation catalytic converter and the particulate
filter. The second system component is an auxiliary tank
containing an aqueous carbonyl diamide solution. The solution,
which has been labelled "AdBlue", is injected
into the exhaust system in small doses. Once in the hot
flow of exhaust gases, it decomposes into ammonia which
in turn breaks down the nitrogen oxides into nitrogen
and water.
The "AdBlue" reducing agent is routinely topped
up at the workshop each time the vehicle is serviced,
without the customer having to lift a finger. Audi ensures
that there is sufficient "AdBlue" to safely
cover the distances between services. Additional benefits
include the fact that "AdBlue" is biodegradable
and the system's guaranteed effectiveness for the duration
of the vehicle's service life.
Audi is a driving force behind the advancement of diesel
engines
The ultra-clean Bluetec diesel engines see Audi hold true
to its tradition of always being at the cutting edge of
diesel technology development. The Ingolstadt brand developed
direct injection technology back in 1989 – since
then, the fuel efficiency of diesel engines has been improved
by around 30 percent on average. Compared to 1989 levels,
the European emission standard Euro 4 heralds a
93 percent reduction in passenger car particulate emissions;
long before the standard came into effect, Audi had already
brought out models onto the market which complied with
the stipulated limits, even without a particulate filter.
The Audi philosophy has always been to offer customers
the best possible solution. And as the only good emissions
are those which are not created in the first place, Audi
engineers gave top priority to implementing internal engine
measures that would further refine the combustion process.
The common-rail technology in the new Audi Q7 V12 TDI
with an injection pressure that has now reached the 2,000
bar mark is, for the moment at least, the last link in
a long chain of diesel developments.
Others include the four-valve-per-cylinder technology
and the accompanying swirl and inlet ports for controlling
the airflows, as well as the controlled and cooled system
of exhaust gas recirculation; the latter of these innovations
is of great importance for the future of diesel engines
at Audi.
Higher fuel prices, improved diesel infrastructure
The growing trend towards diesel power which is emerging
in the US has been prompted by a number of developments.
The sharp increase in energy prices has raised public
awareness of the importance of making economical use of
resources.
The infrastructure of filling stations stocking diesel
fuel for passenger cars is growing, at the same time increasing
availability of the low-sulphur diesel fuel (containing
less than 50 ppm sulphur) that is one of the fundamental
requirements for using Bluetec technology and particulate
filters. Irrespective of this, Audi is promoting the development
of sophisticated synthetic fuels derived from biomass
or natural gas, which by their nature contain considerably
fewer pollutants.
The Q7 3.0 TDI will be the first model from Audi to showcase
the all-new, ultra-clean Bluetec technology when it is
launched in the US in late 2008. Further models are set
to follow. And other countries apart from the United States
have voiced an interest in the new, extra-green diesel
engines, including Japan, China and, not least, the Europeans.
High-tech diesel engines from Audi
Technical superiority
The new V12 TDI with its supreme performance is a trademark
Audi engine. Ever since it first invented the TDI engine
18 years ago, the brand has played a pivotal role in advancing
technology in this field. Diesel engines from Audi are
powerful, efficient and smooth, and they have demonstrated
their superiority both on the road and the racetrack.
368 kW/500 bhp – the new V12 TDI engine in the Audi
Q7 is a veritable pageant of technology and represents
the new pinnacle of passenger car diesel development.
The twelve-cylinder power unit provides unquestionable
proof of the pre-eminent technological expertise at Audi.
18 years after the Ingolstadt brand invented the modern-day
TDI engine, it is presenting it in an all-new high-tech,
range-topping guise.
The wide-ranging pool of know-how at Audi is also plainly
in evidence in the brand's other large diesel engines
which likewise succeed in fusing sheer power with excellent
efficiency. The two V6 TDI units summon 132 kW/180 bhp
and 171 kW/233 bhp respectively from their capacities
of 2.7 and 3.0 litres, with the V8 TDI drawing 240 kW/326
bhp from its 4.2 litres. The TDI engines from Audi are
full of power and torque, yet they are also efficient
and economical, as well as being quiet and smooth.
TDI engines are full of power
The three-litre TDI unit propels a variety of Audi models,
ranging from the mid-size A4 up to the Audi Q7 high-performance
SUV. Its 171 kW/233 bhp equates to an output of 57.6 kW/77.9
bhp per litre – a figure which up until just a few
years ago was unprecedented outside of the sports car
faction. In all of the models it is fitted in, the 3.0
TDI drives all four wheels via the quattro permanent four-wheel
drive system, yet another Audi technology whose tremendous
potential for motoring pleasure and driving safety underscores
the brand's sporty essence.
The three-litre diesel engine ensures dynamic performance.
It powers the Audi A8 luxury saloon, for example, to a
majestic top speed of 243 km/h and from nought to 100
km/h in just 7.8 seconds. Yet more evidence of the Audi
brand's exclusive expertise can be found in the A8 3.0
TDI quattro: its body tips the scales at a mere 222 kilograms
thanks to its state-of-the-art Audi Space Frame (ASF).
ASF reverses the weight spiral. Recently, Audi received
the European Body Car Award for the TT body with its hybrid
construction that makes intelligent use of aluminium combined
with steel.
TDI engines are full of torque
The great strength of all diesel engines from Audi is
their immense torque. The pulling power of diesel engines
clearly surpasses that of comparable petrol units. What's
more, their power is on tap at very low revs, just above
idling speed in fact – meaning that the driver merely
has to coax the accelerator pedal for a smooth yet persistent
build-up of thrust. Consequently, the pulling power is
there whenever it is needed, making for a composed and
relaxed driving style.
Built in the vein of a classic American small block, the
three-litre V6 transmits as much as 500 Nm of torque to
the crankshaft at engine speeds as low down as 1,400 -
1,500 rpm. The diesel powerplant generates an exceptional
168.5 Nm for each litre of capacity.
TDI engines are efficient and economical
Diesel engines make more efficient use of the energy contained
in the fuel they run on than petrol engines do. Audi has
played a decisive role in the development of the many
different solutions that have been devised to capitalise
on this fundamental principle of physics – four-valve-per-cylinder
technology for an optimum cylinder charge in any operating
situation is just one example, as is the principle of
variable turbine geometry used in turbochargers.
The A8 is a saloon of stately proportions, measuring 5.06
metres in length, but even in such a large car the 3.0
TDI demonstrates astounding restraint in terms of fuel
consumption. On the EU driving cycle, it limits itself
to an average of 8.5 litres per 100 km, while the 2.7
TDI in the Audi A4 is even more frugal, burning just 6.7
l/100 km.
Such high efficiency heralds more than just financial
benefits for drivers, especially on long journeys: thanks
to the 90-litre tank capacity, motorists adopting a relaxed
driving style can cover far in excess of 1,000 km between
refuelling stops – not only does this cut costs,
it saves time and nerves too.
TDI engines are quiet and smooth
The sound from Audi's latest direct-injection diesel units
is barely perceptible to passengers' ears, as they run
every bit as quietly as their petrol counterparts. This
is partly down to the extensive development work carried
out by the acoustic engineers at Audi. Carefully positioned
finning on the cylinder blocks nips vibrations in the
bud, while all of the potential paths via which vibrations
could be transmitted into the interior have been eliminated
from the engine mountings and bodyshell.
One of the key advances can be attributed to the common-rail
technology, as it virtually gives the control unit free
rein over the injection of fuel, which can take place
up to five times during each power stroke. The pilot injection
phases take place well in advance of the main injection
to produce a more gradual pressure build-up for smoother
combustion. The innovative piezoelectric injectors used
by Audi in its large diesel engines heighten this effect
with their extremely fast, high-precision actuation, finally
putting an end to the harsh knocking and metallic rattling
sounds normally heard at partial throttle.
Audi – drawing on a wealth
of TDI expertise
The engine unveiled by Audi at the Frankfurt Motor Show
in the late summer of 1989 was nothing less than an absolute
sensation: exhibited in the Audi 100, the five-cylinder
turbodiesel mustered 88 kW/120 bhp and 265 Nm of torque
from its capacity of 2.5 litres. It was the first ever
passenger car diesel engine to feature direct injection
and fully electronic management – in short, the
world's first TDI.
The beefy power of the five-cylinder drive unit redefined
standards in the diesel segment when it went into series
production in 1990. And Audi has been consolidating its
head start ever since with one new development after another.
1991 marked the debut of a four-cylinder TDI model which
extracted 66 kW (90 bhp) and 182 Nm from its capacity
of 1.9 litres. Four years later its output was upped to
81 kW/110 bhp, thanks partly to the inclusion of a brand
new turbocharger with turbine vanes that could be adjusted
flexibly to match current requirements. The advertising
slogan "Where's the tank?" made the TDI's proverbial
economy and its tremendous operating range famous in Germany
– the 66 kW/90 bhp variant of the 1.9 TDI made do
with a mere 5.1 l/100 km in the Audi A4.
The five-cylinder engine's output was uprated to 103 kW/140
bhp in 1994; coupled to a six-speed gearshift and optional
four-wheel drive, it advanced to the status of the first
TDI quattro. With vital statistics reading 290 Nm of torque
at 1,900 rpm, a top speed of 208 km/h, 9.9 seconds for
the 0-100 km/h dash and a Euromix fuel consumption of
6.0 l/100 km, it set a new benchmark for sporty touring
saloons to measure themselves by.
The world's first V6 TDI passenger car engine followed
in 1997. Fitted with a four-valve cylinder head –
yet another major innovation on the TDI front –
it had an output of 110 kW/150 bhp. Audi premiered its
first diesel engine with the pioneering common-rail injection
system in 1999 when it unveiled the
165 kW/225 bhp V8 TDI. The very same technology is employed
by the current family of V diesel engines, ranging from
the 2.7 V6 TDI and the 3.0 V6 TDI to the 4.2 V8 TDI and
finally the new six-litre V12 TDI.
For 18 years now, Audi has been harnessing all of the
innovative flair it has amassed in this field to constantly
push back the limits of what is possible. The TDI engines
have been pivotal in the Audi brand's rise to the rank
of sporty premium manufacturer; today, every second Audi
that is sold worldwide has a diesel engine under the bonnet.
The TDI engines have enjoyed an unparalleled triumph –
and the success story is set to continue apace.
TDI on the racetrack: a quiet,
efficient, dominating force
Initially, even the drivers could not believe their ears
– seasoned professionals of the likes of Tom Kristensen
and Frank Biela suddenly had to change their habits. Previously,
they had used the engine noise emanating from their open
sports cars as an important yardstick – and now
the engine noise faded out altogether above a certain
speed, so quiet was the V12 TDI in the new R10.
The V12 diesel race car from Audi has taken motorsport
into a whole new era. Designed in accordance with the
regulations that govern the Le Mans 24 Hours, the 5.5-litre
TDI racing engine is a cut above the rest. With its prodigious
torque of over 1,100 Nm, it comfortably outperforms any
petrol model. At its rated engine speed, over 478 kW/650
bhp is on tap – translating into a top speed in
the region of 330 km/h.
A further forte of the V12 TDI is its low fuel consumption.
Measured against its already extremely efficient predecessor,
the R8 with petrol direct injection, the R10 TDI burned
considerably less fuel at Le Mans. This was despite the
fact that the diesel was unable to make the very most
of its strengths on the Sarthe circuit with its long straights
and a full throttle ratio approaching the 75 percent mark.
The high range was crucial to victory
The high range and the resulting reduction in the number
of refuelling stops proved to be a crucial factor in the
victory at the classic 24 Hours. Frank Biela (Germany),
Emanuele Pirro (Italy) and Marco Werner (Germany) only
had to call in at the pits 27 times in their car with
start number 8.
They completed 380 laps – 5,187 km – at an
average speed of 215.409 km/h.
Spurred on by its triumph at Le Mans, Audi went on to
achieve something that no other manufacturer had before
it – the R10 TDI won all eight of the races it competed
in over the course of the 2006 season. The sequence of
victories spanned the breadth of the United States, starting
in March at the 12 Hours of Sebring in Florida and culminating
at Laguna Seca in California in October.
In the American Le Mans Series, Scotsman Allan McNish
together with Dindo Capello from Italy emerged as the
overall champions of the large LMP1 category long before
the season had drawn to a close. With a total of 23 wins
under his belt, Capello is the most successful ALMS driver
of all time. Audi also took the constructors title in
the large LMP1 category by a substantial margin after
racking up 215 points ahead of Lola in second on 160 points.
A panel of judges from the British magazine "Race
Engine Technology" voted the V12 TDI in the Audi
R10 TDI "Race Engine of the Year 2006" and "Alternative
Race Engine of the Year". The engine's design engineer
Ulrich Baretzky, Head of Engine Technology at Audi Sport,
and the Head of Audi Motorsport
Dr. Wolfgang Ullrich perceive the V12 TDI as a perfect
illustration of motorsport and series production cooperating
closely with one another.
Transfer between motorsport and series production
"We can avail ourselves of the expertise and test
facilities of our colleagues in series development,"
remarks Dr. Ullrich. The know-how flows both ways though,
with technological highlights from the racetrack often
injecting vital new stimulus into series development.
Audi performed a similar technology transfer back in the
late 1980s. At that time, the touring cars from Ingolstadt
were dominating the TransAm and IMSA races thanks to their
quattro drive and turbocharged petrol engines that generated
in excess of 700 bhp in some cases. 20 years on, large-scale
series development is once again reaping the benefits
of motorsport technology.