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Audi Introduces V12 Diesel Passenger Car Concept

The Audi V12 TDI. Click to enlarge.

Leveraging the work it did with its V12 TDI R10 racing car (earlier post), Audi has applied a 6.0-liter, Euro-5 compliant 12-cylinder diesel TDI engine—the first V12 passenger car engine—in a concept version of the Audi Q7. The Audi Q7 V12 TDI study delivers 368 kW (493 hp) and a massive 1,000 Nm (737 lb-ft) of torque.

The power of the turbocharged V12 TDI takes the SUV from 0 to 100 kph in 5.5 seconds, with fuel consumption of 11.9 liters/100km (20 mpg US).

Performance of the engine. Click to enlarge.

The Q7 V12 TDI’s cylinders actually sweep a greater volume than the racing engine, which has a capacity of 5.5 liters. Its 5,934 cc are produced by a bore of 83.0 millimeters 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 millimeters. Measuring just 684 mm long, the V12 diesel has an extremely compact design that enables it to fit into the 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.

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% more rigid than cast iron and twice as resistant to fatigue.

Use of this material enabled the development team to make the walls thinner, paving the way for a potential weight-saving of around 15% 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.

Piston and valve system for the V12. Click to enlarge.

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.

Bosch supplies a 2,000-bar injection system for the V12. The hole diameter of the eight-hole injector nozzles has now been reduced to a mere 0.12 millimeters. 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. The improved combustion efficiency increases power output while reducing both fuel consumption and emissions.

More than 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.

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.

Two variable vane geometry turbochargers supply compressed air—each to one bank of cylinders. The 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 are key in achieving the peak torque of 1,000 Nm.

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 Q7 V12 TDI study.

The Audi Q7 V12 TDI is Euro-5 compliant. At partial throttle, up to 50% of the exhaust gases are fed back into the intake air via the Exhaust Gas Recirculation system to reduce NOx emissions. The extensive recirculation system incorporates a water cooler which reduces the temperature of the exhaust gases sharply.

The V12 TDI is coupled with a new six-speed tiptronic transmission. The quattro driveline 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.



The power/torque specs of this engine is a bit much. From an engineering standpoint, I like this. There are many technologies featured here in this showpiece that can go into smaller engines for highly efficient B or C segment car (subcompacts & compacts). Some of which are already in production, in one form or another.


Perhaps Audi should put this engine in a light tank or some such.


Oops, I was looking for GCC. I must have stumbled into Brown Car Congress by mistake.

Roger Pham

A marvelous piece of technology, nevertheless, still belongs in "Brown Car Congress!" However, divide this engine into 3 or 4 pieces, and each piece will fit neatly in GCC!

Thomas Pedersen

All the technology in this engine really gets the saliva flowing, but 20 mpg is remarkably low for a 2007 diesel :-(


I suppose it is usefull to see what the stupid half of the population are up to!

Mark A

Consider the outcry if GM had introduced this?


What are you people going on about? This is a fantastic engine, and an excellent example of advanced diesel technology.
A new Ford GT (on petrol) with half the torque and same engine capacity gives you a wopping 6-10mpg.

Take the Audi engine and divide it into three and you have yourself something like a lightened 2.0l VW Golf TDI engine, and you know what mpg that puppy would provide.

Oh, sorry, its not like a Prius, which is the most marvelous car eva coz it runs on flowers and joy.
Well correct me if I'm wrong but doesn't the much loved Toyota company also make the Tundra.
Here's a quote from an earlier post:
"An all-new 5.7-liter i-Force V8 engine is available for all the Tundra models. The 5.7-liter engine develops 381 hp (284 kW) at 5,600 rpm and 401 lb-ft (544 Nm) of torque at 3,600 rpm. Tundra 4x2 and 4x4 models equipped with the 5.7-liter engine will have city/highway fuel economy rating of 16/20 mpg and 14/18 mpg respectively." Wuu,. half the torque.

And no, I'm not simple in comparing both the Ford GT and Toyota Tundra petrol engines against the diesel equivalent in the Audi.

What I am comparing however is large capacity performance engines on the market. (for road vehicles)
And from where I stand Japan and the US don't appear to have an equivalent capacity engine (diesel or otherwise) that offers the same power, torque and economy in one package. So stop bagging it.

And before you go off on a "V12 is excess" speech, consider that this engine can just as easily be nestled in a bus or truck chassis, easily justifying that fuel economy (which is not that bad considering my crappy 1.8 litre 1987 Toyota Celica had that fuel economy. We've come far.)

Harvey D.

Marvelous engine. Just in the wrong vehicle. Can't see the 110 lbs Mrs taking the kids to school or go shopping with a V-12, 500 HP ++.

Powerful enough for medium and large trucks and buses. May be the ideal engine for war machines.


This engine maybe also suitable for Police Patrol boat, Search and Rescue boat, Passenger boat, Jet Boat engine for Jet Boat tour (which popular in New Zealand), medium size - high speed modern Bus, Fire fighting truck (which need speed in order to race with time), or any added value purpose rather than hauling SUV with only 5 passengers.

Thomas Pedersen


You are actually right. Moving a house at 0-60 mph @ 5.5 s while maintaining 20 mpg is actually quite impressive.


Nick, NooGums, Harvey D,
Perhaps in a wheeled IFV, like the B1
or the Piranha
family (includes US Stryker and LAV III). The torque is a bit low for military diesels or commercial/military trucks, and the cylinder count a bit high for these markets. Perhaps a 7-8L V8 version, with 300-400hp, and 1000lb-ft torque will do.

Rafael Seidl

Gents -

interesting that so many of you should advocate putting this engine to work in heavy-duty applications. Unfortunately, it is derived from a race engine and probably wouldn't last long enough in the vehicles you mention. An HDV engine has a life expectancy of 1-1.5 million kilometers, many of which would be driven near full load. 24 hours at Le Mans is an extremely tough test but it does not prove suitability for heavy-duty apps.

Still, the military might be interested in this engine for supply trucks, lightly armored wheeled reconnaissance vehicles and UAVs, because it's small and fuel efficient for its rated power.


Well, at 490hp it would be ideal for the Class 8 truck category.
But will Audi able to convince the Good-0-Boys to give up their Peterbilts and Kenworths.

my name

"what the stupid half of the population are up to"

This is a European car. In Europe vehicles with such a powerful engine are owned only by really rich people. So it's not like in the USA where average people can afford V-8-10-12 cars.


I only have two words for the V12 TDI. MODERN MARVEL.


my name:

Let's see, manufacturers of 12 cylinder engine cars include: Aston Martin, Lamborghini Murciélago, Mercedes Benz, Bentley, Ferrari, Audi, BMW, Maybach, and Rolls Royce. Average cost $300,000.00. Which is clearly why an "average" American drives these cars.

Such are the unfortunate myths of the rich against poor ministers.


I think this engine would also be appropriate for ambulances, and perhaps for some armored trucks which transport cash.

my name

OK, I admit that it is not correct that average Americans can afford V-12 cars.

But I think it is correct to say that average Americans can afford V-8 and even V-10 cars, for example the European made VW Touraeg V-10. While most Europeans who buy a Touareg, buy it with a V-6 engine. And V-8, V-10 is only to be found in luxury cars in Europe, while common in affordable US cars.


Um audi is and always will be about performance and luxury.

The people that buy thier cars dont need toworry about fuel costs. They do in general need to worry about being attacked and thus very likely many of these v12 cars will in fact get aftermarket armor installed.


I pesume it will be used to power the luxury cars that cart around the psychopaths that are running most big buisness today , no empathy = no respect for the eviroment!


Actauly for an engienof this power the fuel econ is amazing. I know many cars with engineslike this thatare alot ligter then an suv get sub 8mpg.


Stick it in the R8 and it will be amazing.


kick ass engine. This is so much better than a prius


Jorge said:
"But I think it is correct to say that average Americans can afford V-8 and even V-10 cars, for example the European made VW Touraeg V-10. While most Europeans who buy a Touareg, buy it with a V-6 engine. And V-8, V-10 is only to be found in luxury cars in Europe, while common in affordable US cars"

The average american cannot afford a $70000 V10 Touraeg, sorry. Sure, V8 engines are common in the larger american cars, but most cars that the average american drives have V6 engines - Accord, Camry, all the minivans, etc. Most Detroit family cars even have V6's.

In any case, the power to consumption of this engine seems nice, and the application in the Q7 in this case is definitely targetted at the rich folks (top 10%, maybe even top 5% income earners). For this market, the power and performance is what people look for. The comparatively better mileage this provides vs. gasoline engines is a bonus. The cars will sell regardless of their environmental impact, so why not make them a bit better for the environment?


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