Are Diesel Cars In Europe Starting A Long Slow Decline?

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2012 Volkswagen Passat TDI Six-Month Road Test

2012 Volkswagen Passat TDI Six-Month Road Test

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A few weeks back, we looked at the numbers showing diesel sales in the U.S. increasing, just as hybrids are becoming more popular in Europe.

That's a shift from current preferences, which sees more than half of European car sales fitted with diesel engines, but more hybrids sold in the U.S. than anywhere else.

Those norms are unlikely to change in the near future, but there are some signs that diesel may now be at the peak of its popularity in Europe.

A host of regulatory and technical factors may lead to a slow decline in diesel sales in Europe--the only real stronghold for diesel passenger vehicles--over the next decade and beyond.

Why diesels are good

The popularity of diesel engines for passenger cars has exploded in the last two decades, to the point where diesel is now the dominant fuel in Europe.

Older diesels were slow, noisy, dirty and unrefined. Technological advances have addressed all those issues since 1990, to the point where modern diesels not only outperform their gasoline counterparts on the road, but also often match them on refinement.

Direct injection, turbocharging and sequential turbocharging, and other technologies have seen performance rise as efficiency does likewise.

Couple the fuel-efficiency gains with the lower taxes on diesel vehicles in several European countries, and it's no surprise that they've become popular.

Even in countries like the UK, where diesel fuel is more expensive than gasoline, half of all new cars sold are diesel. That's due to lower CO2-based road taxes and fuel economy potentially good enough that it offsets both the purchase price and the fuel costs.

Why diesels are not so good

The honeymoon period could be ending, however--and it's partly down to that old issue of diesels being dirty.

A modern diesel typically emits fewer hydrocarbons and less carbon monoxide than a gasoline vehicle, but greater amounts of nitrogen oxides and particulate matter.

diesel and AdBlue fillers in Audi Q7 TDI

diesel and AdBlue fillers in Audi Q7 TDI

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The latest line of attack combines urea injection and diesel particulate filters to reduce these emissions--at a notable increase in the cost of a diesel engine fitted with these systems.

Most smaller European diesels don't currently need urea injection, but new "Euro 6" emissions standards will arrive in September 2014.

They're roughly equivalent to U.S. standards that have seen urea injection fitted to every passenger diesel sold in the States except the Volkswagen Golf and Jetta and 2014 Mazda6 diesel.

The industry expects a further tightening of standards, with "Euro 7" already being discussed for 2020 or later. That will only make it harder and more expensive to build already-pricey diesel engines.

At some point, the extra expense of a diesel car simply won't be worth the extra money over increasingly efficient (and cheaper) gasoline vehicles--and the market will ebb.

Longer-term maintenance is causing worries too, with those necessary particulate filters often failing for city-bound drivers.

Ironically, economical low engine speeds mean exhaust gases don't get hot enough to burn off the particulate matter--leading to clogged filters and expensive replacements.

Small gas engines improving

There are already signs of this happening. Only a few years ago, most of Europe's smallest vehicles could be bought with diesel powerplants in sizes as small as 1.0 liter.

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Comments (16)
  1. Any time a news headline starts with a question, the answer is "no". An old journalist trick to direct eyes to the article.

    "At some point, the extra expense of a diesel car simply won't be worth the extra money over increasingly efficient (and cheaper) gasoline vehicles--and the market will ebb."

    Even if that were the case, there is still this "little detail" of modern diesel engines outperforming their gasoline counterparts. For example, the new mazda6 Sky-D has the torque comparable to a 4.0 L V8 gasoline engine.

    Assuming your conjecture is correct, which I seriously doubt, the question now becomes: at which price point is it worth more to get the more complex gasoline engine? The answer is likey: "never".

  2. How is the gasoline engine more complex than the diesel?

  3. spark plug is about the only extra part that I can think about...

  4. Annatar - please don't let your bias cloud your judgement. That modern diesels are getting more and more expensive to meet tighter and tighter emissions controls is very real, and any argument based on that fact isn't conjecture.

    Your comment on the Sky-D is a little off-base too. Diesel torque is compelling, but it's developed over a fairly small range of engine speeds. Useful if you're in that band, not so great if you aren't. I don't wish to glorify gasoline V-8s on Green Car Reports, but I suspect that V-8's torque is a little more usable if you stomp on it in top gear from 1k rpm...

    And as others have stated, I fail to see how gas engines are appreciably more complex. No urea injection, particle filters etc required for a start...

  5. The SKY-D has a flat torque curve from 1,800 (or 2,000 RPM, depending on the version of the engine) to 5,500 RPM. It is literally like a gasoline V8.

    Do diesels have to meet more and more stringent emission laws? Yes, they do; nobody is disputing that, and it is a good thing that they are getting cleaner and cleaner.

    What I am questioning is your assertion that tightened emission standards equal higher prices and less diesel cars sold. Someone here already posted data which claims the number of diesel cars sold in Europe stayed the same over previous year, which, considering Europe is in dire financial straits right now, is impressive in and of itself.

  6. "And as others have stated, I fail to see how gas engines are appreciably more complex. No urea injection, particle filters etc required for a start..."

    Urea injection is only found on certain models, and it is still mechanically simpler and less error prone than coils and spark plugs.

    The diesel engines like the one in certain Volkswagens and mazdas are even simpler. No ignition, just a particulate filter. They do not come any simpler than that right now, and soon, overhead cams will be history too (for reference, see what Koenigsegg is doing with that).

  7. @Annatar: With the possible exception of Mazda, every diesel maker will fit urea injection to every diesel sold in Europe and North America once Euro 7 standards come into force in 2014.

    For instance, Volkswagen has already said it will fit urea into the new Golf and Jetta using its new 2.0-liter EA288 diesel in both markets.

    Markets with less stringent emissions rules may continue to see non-urea diesels, but I'm aware of no makers other than Mazda that claim they can forgo urea injection under Euro 7.

    Are you aware of any 2015-or-later diesels in Europe or North America (aside from Mazda) that will NOT have urea?

  8. As far as I know, the engine in the Jetta and Jetta SportWagen will still not require Urea, even in the new models. Other than the Golf, I do not recall an announcement from Volkswagen that those models will need Urea.

    Whether a car needs Urea depends primarily on the weight of the car and the engine design. mazda obviously put everyone else in their place clearly demonstrating that a Euro VI / Tier II Bin 5 vehicle does not need Urea when the engine is redesigned.

    Urea is a hack. Some manager somewhere wanted to meet some imaginary deadline, like they often do, so that he can report to his boss "yeah, it's done!" and get a nice fat bonus, rather than rethinking the engine and the weight / rigidity of the vehicle like mazda did.

  9. @Annatar: I spoke to Volkswagen engineers at a roundtable event last fall at the Paris Motor Show. They confirmed that the TDI models will be fitted with urea when the seventh-generation Golf (built in Mexico) comes to the U.S. in Spring 2014 as a 2015 model. When the next Jetta on the same MQB architecture is launched, it too will follow suit. VW feels that urea will be necessary to meet Euro 7.

  10. @Annatar: And while you may view urea as a "hack," it would appear that it's a hack that essentially every diesel maker *except* Mazda plans to employ.

  11. @Annatar: Actually, a slight revision to my notes above. In speaking to Audi and VW engineers, it appears they while they plan to fit urea to the EA288 engine to meet Euro 6, that engine will launch in the U.S. for the 2015 model year without it--and then gain it as soon as U.S. standards tighten again.

    So, for the 2015 model year, it may still be that Audi, Mazda, and VW have urea-free engines in the U.S. All other makers will use urea.

  12. Thank you for that update. Eventually, they will all have to redesign their engines to not use Urea; this is just a temporary measure to get them by. mazda bit the bullet early; in a few months we shall see if that measure will start paying dividends in terms of unit sales.

  13. According to recent data from Europe, percent of sales of diesel vehicles (55.3%) was unchanged in 2012 compared to 2011 (

    Furthermore, there are some doubts that GDI gasoline vehicles will be able to meet the Euro 6 particle number emission limit scheduled to come into effect in 2014 without a particle filter. That will likely not only significantly increase costs, it may lower the efficiency of GDI (which hasn't really closed the fuel efficiency gap on diesels much as it is).

  14. One can hope.

  15. It will be demographics as much as anything that do for Diesel, the population is getting older and the young folk aren't interested in cars anyway.

    Older people downsize and the smaller the car the less likely it is to have a diesel engine.

    Those Fiendish engineers at PSA and VW will keep Diesel technology compliant with whatever the EU can throw at them but there will be a commensurate improvement in petrol engine consumption as well which combined with smaller cheaper cars being the norm will reduce the demand for Diesel engined cars.

  16. "@Annatar: And while you may view urea as a "hack," it would appear that it's a hack that essentially every diesel maker *except* Mazda plans to employ."

    That is because except for mazda, no manager inside of any of these vehicle manufacturers had the guts to completely redesign a car from scratch like mazda did. Everybody is copying TOYOTA's incremental improvement, but in this particular case, I feel that this hack alone warrants a complete redesign. Then they can start the incremental improvement cycles again.

    One could even argue that mazda's redesign around "SkyActiv" is in and of itself a result of incremental improvement, so what does that say about internecine political warfare and position jockeying inside of other car companies?

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