Autobahn A8 runs between Munich and Stuttgart. The white Audi Q7 is headed for Augsburg. On a flat, straight stretch of autobahn, the tachometer is redlined at a leisurely 4200 rpm, yet the digital speedometer readout climbs to 287 kph - nearly 180 mph. That's what the world's only production twelve-cylinder diesel engine can do in a nearly three-ton SUV.
This 5.9-liter V-12 does Rudolf Diesel proud. When the engineer made this same trip more than a century ago, commuting between his mansion in Munich and the MAN research facility in Augsburg, he had to take the train, which was then pulled by a steam engine. "What a waste!" Diesel would rant. "In a year or two, my petroleum-fed compression-ignition design will ring in a new era. It's going to be three times more efficient, much more economical to run, and significantly cleaner than that noisy puff-puff device."
One hundred and sixteen years after the first patent was granted, diesel has long since become a global household name. It powers locomotives, ships, and motor vehicles; it drives factory equipment and electric generators. As far as automobiles are concerned, its most extreme variation can be found under the hood of our massive Q7. Inspired by the racing diesel engine that won Le Mans, the Audi V-12 demonstrates what can be achieved when the engineers work overtime and the accountants take a year or two off. No, this engine will never be profitable. Instead, its mission is to act as a high-tech brand enhancer. Does this burly overachiever send the wrong message for the times? Not really. Over about 2000 mostly lead-footed miles, our twelve-cylinder test car averaged a relatively impressive 16 mpg, considering its power and weight.
In the Manroland museum in Augsburg, one can still marvel at Rudolf Diesel's original work, such as his third prototype engine. Codenamed 25/40 and completed in 1896, the monstrous single-cylinder device developed 18 hp at 154 rpm - not exactly the stuff dreams are made of today. But back then, that was enough to elevate Diesel to the same elite level as Nicolaus August Otto, inventor of the four-stroke, spark-ignition gasoline engine. Both engineers were backed by powerful corporate supporters: Diesel had signed early licensing deals with MAN and Krupp, while Otto had teamed up with Deutz.
But there was also a dark side to Diesel's career, which stood in stark contrast to all the fame and fortune. "There is turmoil inside my head," he would complain repeatedly. "Turmoil which feels very much like lunacy." At the age of forty, he spent three months in a psychiatric hospital, and he never fully recovered from persistent nervous complaints. The other issue that overshadowed his whole life was the endless controversy concerning the validity of his patents. Every modification to the original concept required a legally acknowledged amendment - which was duly fought in court by his opponents, who quickly grew in number and strength.
In terms of traffic, Paris is a zoo. The most feral animals are taxis and buses, but bruised delivery vans driven by iPod junkies come a close third. Everybody parks by ear, most brains are either in neutral or on the phone, and turn signals function only as hazard flashers to double-park for the duration of a café au lait et un croissant. In this crazy environment, the Q7 is about as out of place as a peacock with a permanently spread fan. What helps at the traffic-light grands prix - which usually start even before the lights turn green - are the 738 lb-ft of torque that enable our great white beast to spring forward like the tongue of a chameleon aiming at a hapless insect.
Bienvenue à Paris, where Rudolf Diesel was born in 1858, where he lived in poverty until he was twelve, and where he returned to run Carl von Linde's ice-making factory from 1880 to 1890. Our Audi feels like a baby Kenworth as we maneuver through the narrow streets, passing landmarks like Sacré Coeur, the Eiffel Tower, the famous Opéra, and Place Pigalle. Right across the street from Diesel's birthplace at 38 rue Notre-Dame de Nazareth, we stumble upon a most modern antithesis to the diesel engine. In a redesignated parking bay, the city has installed one of about fifty bicycle charging racks, where your electric bicycle can be recharged overnight or during business hours. Diesel, who late in life studied biofuel and solar power, would have loved this scene. A few blocks away, he would have no trouble recognizing his parents' leather shop on rue de la Fontaine au Roi, which has been only mildly refurbished since the days when young Rudolf delivered handmade purses, belts, and satchels to customers after school.
Diesel went to school in Paris, but he spent most of his free time in the grand Musée des Arts et Métiers, where he devoured every detail of such pacesetting new technologies as steam power, electricity, photographic film, telecommunications, and the phonograph. Nicolas-Joseph Cugnot's steam vehicle, in particular, left a lasting impression on the boy. Diesel emigrated to England with his family in 1870. Later that year, a relative helped get him into the university in Augsburg. In 1880, the certified engineer Rudolf Diesel returned to the Seine, and in 1883, he married the love of his life, the American-born teacher Martha Flasche, with whom he had three children.
In the cut and thrust of Paris, the Q7 V12 TDI drinks fuel at a prodigious rate. On the autoroute headed toward the Belgian border, however, the onboard computer indicates truly ascetic consumption of about 26 mpg. Considering the heavily enforced 81-mph speed limit, four cylinders would have been plenty for this leg of our trip, which takes us to Ghent, Belgium. We entertain ourselves by playing with gadgets like the remarkable Bang & Olufsen sound system; the adjustable air suspension, which features three different calibrations and five different ride-height settings; and the multimedia system, which boasts digital audio and TV, CD and MP3, DVD navigation, Bluetooth connectivity, and a rear-seat entertainment package. This Audi beats the train in terms of creature comfort but not in speed, as is repeatedly demonstrated by the near-silent TGVs that keep overtaking us.
All that's missing is the new Q5's drive-select system, which allows you to dial in your preferred steering, throttle, transmission, and suspension tuning. And rather than a dual-clutch transmission, the Q7 V12 TDI makes do with a standard automatic with six, rather than seven or eight, forward speeds. Those who prefer to change ratios manually can do so via the manu-matic gate or the steering-wheel-mounted paddles. Options include radar-based cruise control, which is better than previous iterations; lane-maintaining and -changing assistants, which range from useful to annoying; and the advanced parking system, which adds a real-time image relayed by a camera to the familiar mix of beeps and warning lights.
The unrivaled prime attraction of our snow-white sport-ute is, of course, the mighty diesel engine. Thanks to its 60-degree bank angle, the V-12 is devoid of shaking forces and moments. You might think that this guarantees absolute smoothness, but that isn't the case. Although the engine is well composed at idle, even mild accelerator action has the same effect as poking a stick at the glowing core of a nuclear reactor. In fact, there is so much low-end torque on tap that an extra brigade of computer chips had to be assigned to protect the driveline. Push the accelerator halfway to the firewall, and the 5.9-liter engine lays down a carpet of sound that even the Audi R8 can't match in intensity.
Although not as heavy as Rudolf Diesel's first engine - which was ten feet tall and weighed 4.5 tons - the 48-valve Audi V-12 is no featherweight. This despite the fact that the cylinder heads are aluminum and the block is made of compacted graphite iron, which is significantly stronger, stiffer, and lighter than ordinary gray iron.
Give it stick, and the V-12 will accelerate the Q7 from 0 to 62 mph in 5.5 seconds, according to Audi. We hate to admit it, but going flat out on the autobahn in this behemoth is a priceless pleasure. Eyes glued to their rearview mirrors, the drivers of other cars just cannot believe that they are about to be chased out of the fast lane by a truck.
Continuous patent infringement issues dogged Diesel from the moment his Wundermotor started knocking and fuming. Despite recurrent setbacks, though, he kept on selling the rights to build his engine around the world. At the height of his commercial success, the mustachioed entrepreneur was a millionaire ten times over. As good as he was at making money, however, he was even better at spending it. He founded the General Diesel Corporation, which bought all his patents and aimed to further develop the fuel-oil engine - but it went bust after only twelve years, in 1911.
In 1900, the superstar engineer was awarded the grand prize at the Paris Exposition, a coup he managed to repeat in 1910 with his first small four-cylinder engine conceived to power trucks and buses. But once more, glory and drama sat precariously close together. Persistent quality and reliability problems required the chief's own helping hand in the most faraway places, and the evolution of the truck and locomotive business drained resources. Under increasing financial pressure, Diesel's health suffered severely. Worst of all, the patents on his engine were about to run out, which had a devastating effect on his income. In 1912, period publications reported combined personal losses of nearly 10 million German marks. Diesel was bankrupt - but his engines had finally come to the fore. The first zeppelin took off, the first diesel-engine ocean liner was launched, and the first diesel locomotive rolled off the line. Rudolf Diesel himself, however, had arrived at the point of no return. He had spent, given away, or lost all his wealth. His illness, which had by then taken full control of body and mind, required extreme medication. His ambition, his visions, and his "dedication to form a better and fairer society" had reached a tragic dead end.
The Grand Hotel de la Poste was torn down in 1968. Located close to the opera house, it was the plushest and most exquisite choice for a well-to-do traveler who wanted to spend the night in Ghent, Belgium. On September 26, 1913, Rudolf Diesel checked in at the famous hotel, where he had first met Martha Flasche thirty-one years earlier. We drove to Ghent to retrace the last hours of Diesel's life. It is a fabulous city full of charm, color, and canals that meander in a generous grid through the busy postcard setting. Most of the old town is now a cordoned-off pedestrian zone, but we eventually find a parking spot for the Q7 and help ourselves to hot chocolate with whipped cream and a tall stack of Belgian waffles. From Ghent, it's on to Antwerp, the Q7 tip-toeing through dense fog, heading for the Schelde River and the old Antwerp harbor, where Diesel boarded the SS Dresden.
Nobody knows what happened aboard that ship during the smooth channel crossing to Ipswich on September 29, but Diesel never made it to England. On October 10, a body was found floating in the Schelde estuary. The man's belongings - a pillbox, a pocketknife, a wallet, and a spectacle case - were later identified by Eugen Diesel to be his father's. Some believe that Rudolf Diesel was pushed overboard. Was he done in by a politically motivated German assassin sent to punish the engineer for licensing his engine to England and France? Or was a killer paid by American oil magnate John D. Rockefeller, who allegedly was concerned that Diesel's biofuel findings might undermine his flourishing petroleum business? Or perhaps Diesel met his end at the hands of a British secret service agent, who reportedly had been sent to steal construction drawings of a diesel-engine submarine. The murder theory is also supported by a long list of private and professional projects that seem to indicate that Diesel was, against all odds, still keen to embark on a multitude of new ventures.
The truth is, we don't know what happened that night. But to most of those who have tried to separate the rumors from the facts, suicide seems to be the most credible explanation. After all, Diesel left behind a suitcase crammed with 20,000 marks in small notes and a cryptic letter to his wife. His diary ended on September 29. The only entry for the following day was a small black cross.
Sadly, Rudolf Diesel did not live long enough to witness the first passenger car powered by an engine bearing his name, the Mercedes-Benz 260D introduced in 1936. Whenever he might look down from his vantage point in a different dimension, the gifted thinker and ingenious engineer is bound to be pleased about what has come of his combustion principle, which has proved to be suitable for a variety of fuels.
We could have chosen a lot of other cars for this trip, perhaps the ultraefficient Volkswagen BlueMotion Golf or the clean-burning Mercedes-Benz E300 Bluetec. But a self-made pioneer like Rudolf Diesel, who single-handedly changed the world of engines, deserves the most extreme exponent of his concept. More so than any other diesel engine, this V-12 combines awesome flexibility with commendable frugality. It's a torque monster, yet it uses substantially less fuel than comparable gasoline units. So, even in 2009, Diesel still beats Otto's efficiency.
Does that mean we'd spend ¤130,000 (about $165,000) on a Q7 V12 TDI? Probably not. The Q7 is in many ways an outmoded vehicle - too big, too heavy, too in-your-face, too poorly packaged. But if Audi releases its expected turbo-diesel R8 with this same 5.9-liter TDI, we'll find it much harder to resist. Having said that, there can be little doubt that the Q7 V12 TDI will remain a one-off. Even more than the discontinued V-10 TDI and the threatened V-8 diesel, the V-12 is a reminder of a past that is swiftly being pushed aside by a much tougher and more pragmatic present. What's next? Smaller displacements, fewer cylinders, more turbochargers. And very soon the so-called DiesOtto combined-combustion principle, in which the efforts of the long-ago rivals, messieurs Diesel and Otto, are united at last.