Are Diesels The Future For Luxury Sport Sedans? Audi Says Yes

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2013 Audi A6 TDI

2013 Audi A6 TDI

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As gas-mileage standards tighten steadily through 2025, how do you have a big, powerful, luxurious sedan more efficient?

The Tesla Model S shows one way--make it all-electric--but other makers are taking other routes.

Audi, perhaps more than any other German luxury make, says the answer is diesel engines.

It's long sold its low-volume A3 compact hatchback and Q7 large sport-utility vehicle with TDI diesel engines as an option. One third to more than half of customers order them, depending on the model.

From two to six TDIs

But this year, as part of a wave of new diesel cars for 2014, Audi has added diesel options to four more models: its A6 mid-size sedan, A7 "four-door coupe," A8 full-size luxury sedan, and Q5 compact crossover utility vehicle.

All four vehicles in their TDI form are fitted with a 3.0-liter V-6 turbodiesel, which puts out 240 horsepower and a substantial 406 pounds-feet of torque. Urea aftertreatment to reduce emissions is standard.

'Diesel fuel only' caution on Audi Q7 TDI

'Diesel fuel only' caution on Audi Q7 TDI

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The older A3 TDI uses the same 2.0-liter turbodiesel as the Volkswagen Jetta TDI and Golf TDI models, though that will be replaced in the all-new 2015 A3 with a new, more efficient four-cylinder diesel from the VW Group lineup.

Scott Keogh, CEO of Audi of America, told attendees at last week's Management Briefing Seminars in Traverse City, Michigan, that "diesel is absolutely getting ready for the marketplace."

As quoted in Ward's, Keogh suggested that "far more universal adoption" of the latest diesel engines was on the horizon--and that Audi was "waiting" for customers to catch on.

And while the article reports that Keogh had "little to contribute to his panel’s discussion on sustainability," the Audi chief stressed the company's longstanding experience in winning races--specially the 24 Hours of Le Mans--with high-performance diesel cars.

Highest on highway

Diesels return their best fuel-economy numbers in high-speed highway use, but have slightly less of an advantage in stop-and-go city and suburban use.

That's why many makers quote EPA highway ratings when contrasting optional diesel engines to the gasoline alternatives.

The Audi A6 TDI quattro, for example, is rated at 38 mpg highway--compared to 27 mpg highway for the gasoline A6 with an equivalent supercharged 3.0-liter V-6.

Their city ratings are 24 mpg (diesel) and 18 mpg (gasoline) respectively, and the combined ratings are 29 mpg and 22 mpg.

Diesels often deliver better fuel efficiency than their EPA ratings, unlike some gasoline and hybrid cars.

One model for all markets

So diesels are clearly an easy way for carmakers to get a substantial boost in EPA ratings.

And Audi, like many German makers, is faced with the advent of Euro 6 emissions regulations in its home market--they're roughly equivalent to current U.S. limits.

2013 Audi Q5 TDI

2013 Audi Q5 TDI

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That means it can engineer its future diesel cars to a single standard, eliminating the cost of low-volume U.S. diesel models that must meet more stringent standards than the old Euro 5 limits.

At the low end of the market, those new limits are eliminating some of the smallest diesels. Volkswagen has already said it won't make any future diesels below 1.6 liters, for instance.

More diesels in large cars?

So for the smallest cars, it'll be gasoline engines that are smaller, often turbocharged, and more efficient.

That means you're likely to see more diesels in high-end luxury cars.

Five years ago, would you have expected Porsche to offer U.S. buyers a diesel option on its pricey, high-performance Cayenne sport-utility vehicle?

Still, the degree to which luxury buyers will warm to diesels remains an open question.

How well do you think diesels stack up against hybrids, and even all-electric sport sedans like the Tesla Model S, in the expensive luxury sector?

Leave us your thoughts in the Comments below.


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Comments (27)
  1. Comment disabled by moderators.

  2. @Steeve McCauley: Please resubmit your comment without the rude words, which were flagged by our comment monitoring system. Thank you.

  3. Good step for now. However, The Tesla addresses the... You don't need any fuel issue. They just need to come up with a bigger or better battery and more charging stations and they have dramatically simplified the gas no gas issue,... in my mind.

  4. Diesels: gag me with a spoon!

  5. Coal and nuclear powered, sedan only, no manual transmission Tesla: yuck. So I could write the same for Tesla which is not as wonderful as one might think, at least not from a car enthusiasts point of view.

    The rest are just consumers. And what pray tell do consumers know of such things?

  6. Your post gives me the opportunity to point out that PG&E here in Northern California supplied no coal-fired electricity at all in 2012 and California's only nuke plant was recently permanently shut down. I'm sure you are also aware that Tesla's flat 100% torque/RPM curves require no transmission at all, you being a car enthusiast and all. I think fascination with pointless shifting is a little weird but what do I know? I'm just a consumer.

  7. I think Annatar has expressed his "ideal" many times already, the ONLY electric car he will drive if it is a "station wagon" with a 6-speed manual transmission.

    If Tesla build just one for him, he would have jumped onboard by now. In fact, having a 6-speed manual on a Tesla is doable but "pointless"...

  8. Yes, I would have.

  9. Unfortunately, quite a significant portion of the United States is still powered by coal and nuclear energy.

    As much as I sympathize California, not everything revolves around it; there are 49 other states in the union.

    Yes, I am well aware that an electric car needs no transmission.

  10. @Annatar: But as we have covered many times on this, both in aritcles and comments, the data on carbon emissions from electric cars even in the U.S. states with the dirtiest grids are no worse than the *most* fuel-efficient non-hybrid gasoline car.

  11. Tesla is actually a hatchback, not a traditional sedan.

    Tesla doesn't have manual or auto transmission.

  12. you seem pretty ignorant, the point of a standard transmission is so you can control your speed and power more effectively. With the Tesla you have ULTIMATE control over power and speed with instantaneous response, you are always in a power band because you have max torque and motor regen at all RPMs.

    Also you say coal and nuclear powered is how Tesla charge? do you have any idea how much electricity an oil refinery requires to make gasoline? in 2005 refineries in the US alone needed 48,891,000,000 kWh, after that, transportation, power gas stations, etc then your crap internal combustion engine can only use 20% of the product to move forward.

  13. "ULTIMATE control"? That is quite an assertion, considering that Tesla is all drive-by-wire. If you do not understand the implications drive-by-wire has to control of a vehicle, then it is quite ironic you are debating this with me or anyone else.

  14. Time to move on from the 80's, Billy!

  15. Quite right you are; time to catch up with not only 21st century technology, but also with reality, which is clean diesel technology. Ultramodern, clean, ecological, practical, quiet, fast, and powerful.

  16. I think it is a great move and one that is long overdue.

  17. Since diesels are so great for hwy cruising and hybrids/EVs are great for local efficiency, why don't they build a plug-in diesel electric luxury segament?

  18. Because they would screw it up and sell it as an automatic-only sedan. In best case scenario, one would end up with those idiotic paddles behind the steering wheel.

    That is just too bad. A clean diesel hybrid would be awesome, but only with a manual transmission.

    And of course, they would make it only as a sedan. That is about as useful as a box of rocks, which of course would not fit in the sedan's trunk.

  19. They are available. Just not for the American market.

  20. REAL Sustainability means - we have to STOP burning fossil energy sources. They are to precious to burn them for mobility, for heating houses when there is an other possibility. Audi only sings the "Diesel-Hymn" because they didn't get the range though trying it for 30 years now (internal secrets)

    I live in Germany and I know a lot of electro-drivers. There is NO SINGLE ONE electric driver using "normal" electricity to charge their cars. NO ONE pays triple the price for a car and destroyes his vision by saving 5 ct/kWh for "fossil electricity"

    The "Audi-Hymn" is boring... and this company should not longer be called a "premium car facturer"...

  21. No diesel with luxury sports sedan power (350HP+) will ever match the Tesla.

    im assuming they are switching to diesel for better millage and efficiency, but if they want to make a difference they need to beat 120MPGe with a car that has over 400HP, otherwise you come up short in comparison to the model S. Lower HP models of the Tesla will get at least 120MPGe or better.

  22. Switching to diesels appears to be one of the simplest ways to meet the new CAFE standards.

  23. "@Annatar: But as we have covered many times on this, both in aritcles and comments, the data on carbon emissions from electric cars even in the U.S. states with the dirtiest grids are no worse than the *most* fuel-efficient non-hybrid gasoline car."

    What about the spent fuel rods, the nuclear waste?

  24. @Annatar: Different issue, of course. I suspect that you won't find many electric-car proponents in favor of nuclear power. But as I'm sure you know, there hasn't been a new nuclear power plant built in the U.S. in more than two decades, and there doesn't seem likely to be one any time soon.

    So those plants are PART of the existing grid, and you can't blame them on plug-in electric cars.

  25. I cannot blame electric vehicles; they are inanimate objects, but if the power comes from detrimental nuclear fuel, then I sure can point the finger and the blame at electric car advocates.

    If I had it my way, ALL nuclear facilities in the United States would be shut down and replaced with hydro, sterling engine, wind and solar panel facilities.

    Only then could the electric car advocates claim that their cars were green, and of course there would still remain the issue of polluting the environment to produce them, the same as for any other vehicle.

  26. Erm, have you ever look at how was diesel obtained? Its far from the squeaky clean image you are portraying

  27. Currently it is not much dirtier than being powered by nuclear fuel, that is the worst!

    Did you know that the spent nuclear fuel has to spend years in the power plant being constantly cooled? If the power plant fails, the DIESEL powered generators kick in, and they only have enough fuel to run for about three days. After that, if the rods are not cooled, they eventually cause an explosion, and highly toxic radioactive clouds ensue! The soil and the air will be radioactive for several thousand years!

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