By on February 6, 2017

automobile_exhaust_gas (Wikimedia commons)

Contrary to the popular mantra, there is a replacement for displacement. The problem is tiny engines that harness technology to boost power output aren’t the greenest things on the road. In fact, the emissions created by small two, three and four-cylinder engines are often out of all proportion to the mills’ Lilliputian displacement.

Volkswagen, realizing it’s staring down the barrel of regulatory non-compliance, has vowed to stop searching for the latest gas- and diesel-powered micro-wonder. Small is out. Normal-sized is in.

While the smallest engine offered by Volkswagen in the U.S. is its 1.4-liter TSI four-cylinder, European displacements can drop far lower. The company recently canned its 1.4-liter diesel, stating all future diesels will bottom out at 1.6 liters. A 1.0-liter three-banger currently found under the hood of the super-tiny Polo and Up will soldier on, though VW promises it won’t look at building anything smaller than that.

The proclamations come at a time of increasingly stringent emissions requirements. Studies performed in the wake of the diesel emissions scandal found small-displacement engines were, in normal operation, huge polluters. Despite sipping gas, the wee mills pumped out clouds of nitrogen oxide and other smog-causing particles.

In two years, European nations will enact real-world Driving Emissions Tests (RDE). Many engines built and sold today, especially the small ones, fail the looming standards miserably.

“The trend of downsizing is over,” VW chairman Herbert Diess said at the recent launch of the next-generation Golf, according to The Telegraph.

Volkswagen, consumers, and the environment were burned by the diesel scandal’s fallout, but the widespread proliferation of oil-burning engines across Europe can’t be blamed on the company once-popular technology. Blame governments who tried to turn consumers off of gasoline by taxing it at a higher rate, Diess said.

Diesel use “has not been a customer choice, but a result of favourable tax regimes,” Diess said. “Once you have a price advantage, people will play along.”

[Image: Wikimedia Commons (CC BY-SA 3.0)]

Get the latest TTAC e-Newsletter!

45 Comments on “Volkswagen Stops Its Quest for Tiny Engines with Big Pollution Footprints...”

  • avatar

    I wonder how long it’ll be before VW (and others) will start putting in “normal-sized” engines into cars?

  • avatar

    All of a sudden, Toyota’s slow methodical approach doesn’t seem so bad. Most of their engines are larger and naturally aspirated.

  • avatar

    ” problem is tiny engines that harness technology to boost power output aren’t the greenest things on the road. In fact, the emissions created by small two, three and four-cylinder engines are often out of all proportion to the mills’ Lilliputian displacement.”

    Many of us recognized long ago that the trend towards smaller and smaller displacement motors was not to achieve real world efficiency, but to meet the fuel economy standards as set by very unrealistic government fuel economy “loop” tests.

    • 0 avatar

      I agree it is all about meeting fuel/emission standards tested with unrealistic loops, and the recent VW scandals probably mean more realistic loops may be on the horizon, which will show the tiny motors are actually dirtier in the “real world”.

    • 0 avatar

      So, so true.

      Just about the only new cars that showed better fuel economy in the real world than their EPA ratings were 4-cylinder Volkswagens. Now we know how they pulled that off, at least with the TDIs. I wonder if there’s a similar scandal waiting to happen with the gasoline AE888 1.8T?

  • avatar

    “Despite sipping gas, the wee mills pumped out clouds of nitrogen oxide and other smog-causing particles.”

    Oh this is glorious.

    Bring back displacement, port injection, and natural aspiration.

    • 0 avatar

      You’re likely to get some displacement back. I wouldn’t count on the other two.

      The issue here is high NOx formation that results from very high combustion temperatures inside the cylinder. Very high boost and/or overly lean burn will lead to those very high temperatures. You won’t have the problem at reasonable boost levels with a ratio close to stoichiometric. Direct injection has nothing to do with it, except insofar as it’s been used to run engines ever leaner. The most likely outcome of this finding is slightly bigger, slightly less stressed GDI turbo engines. You’ll still have a 180 hp 1.5T in your Fusion, but no one will try to crank up a 1.2T four or 1.0T three to that power level.

      • 0 avatar

        “You won’t have the problem at reasonable boost levels with a ratio close to stoichiometric.”

        Does something like the CLA45 or Quadrifoglio have reasonable boost levels though?

        If this is an issue on the econo-cars is it also a problem on the high-output side?

        • 0 avatar

          I’d be surprised if 2.0Ts continued being produced with the output levels you see in the AMG 45s, at least for the American and European market.

          In both cases you mentioned I’d expect the solution to be a similar engine with a bit more displacement and a bit less boost.

          • 0 avatar

            “In both cases you mentioned I’d expect the solution to be a similar engine with a bit more displacement and a bit less boost.”

            Not perfect but I’ll take what I can get.

          • 0 avatar

            What VW has with the Amarok. Gone from a 2litre to 3 Litre 221hp Diesel

      • 0 avatar

        You might want to research particulate emissions in DI engines vs MPFI.
        While it is likely MPFI won’t make a comeback, it is very likely Do engines will end up with particulate filters like diesels at some point.

    • 0 avatar

      Port injection never left. It seems most manufacturers are going to a hybrid DI/PI setup to solve the particulate and coking issues.

    • 0 avatar


      Yes we can!

  • avatar
    heavy handle

    This is just about diesel, which never made sense in small cars. They will keep making small gas engines, as will every other group that sells subcompact city cars.

    VW isn’t the first to do this. The new Twingo/Smart is gas-only too, and diesel market share is diminishing in Europe.

    • 0 avatar

      This isn’t just about diesel, but also about the recent crop of very small high-pressure turbo gas engines. In both cases NOx emissions can be a problem.

      • 0 avatar

        Lot more Petrol engines than diesels on the roads. Problem is huge

      • 0 avatar

        It is about diesel. The small displacement petrol engines will be combined with hybridization going forward as the alternative.

        The small diesels don’t make enough heat to keep the AdBlue reacting with the NOx to effectively to scrub the exhaust.

    • 0 avatar

      @heavy handle
      No, far from it , it is INCREASING in Europe. VW Bluemotion a petrol hybrid ,is also sold with diesels as well
      Just Google ,a Name of a manufactuer than ” new Diesel engine ”
      Surprising results. Even Hyundai has a new 1.2litre diesel being introduced

  • avatar

    The problem is this is going to require re-engineering on many platforms. There are quite a few out there that are only built to accept a 4 cyl engine.

    As the Lord and Savior 3800 and the Church of Torque has taught: “4 cyl of no more than 2.5 ltrs and V6 of not less than 3.0 ltrs shall be blessed.”

  • avatar

    Shocking, not shocking that government designed emissions tests haven’t really been good at measuring an engine’s real emissions output.

    • 0 avatar

      “Real emissions output” varies by rpm and load. Putting a squirrel engine in place to do a brawny engine’s job was always lunacy.

      Give me the slow-turning, stump-pulling grunt of a V8 any day. A V6 in a midsizer as a minimum. Less stress, lower emissions.

      Look at what GM has done with the 5.3L V8, and even RAM has made great strides with their 5.7L Hemi V8.

      • 0 avatar

        I drive a Fusion PHEV. Even with the heavy battery in the trunk, the 2.0 I4 is plenty, even without the battery assist. I’m not sure where you all drive that you need all that much acceleration, it’s a rare occasion that I can get the accelerator a quarter of the way to the floor. Save the V6 for midsize crossovers.

  • avatar
    White Shadow

    Sorry, but I just can’t buy into this without some sort of supporting evidence. So I’m being asked to accept that, for example, a turbocharged 2.0L engine puts out more than double the emissions of a 4.0L naturally aspirated engine? Or am I missing something here?

    • 0 avatar

      A bit simplistically; an NA engine emits as a function of RPM, load and throttle position. In a turbo engine, you also have boost. Which is a pretty complex function of the recent history, and now, of all of the above, hence pretty darned complex to model and control.

      The added degree of freedom turbos provide, does allow for enough optimizations to beat displacement in simple fuel economy tests. But it also increases the space of possible combinations of emissions relevant parameters. Such that it is much more difficult to ensure every possible state of the engine runs clean, regardless of how it is driven. Hence, all the gotchas in “real world” driving, despite engines that measure fine in simplistic lab tests.

      Which is why I keep harping on the need for “worst case” testing: Pay the testers bonuses to find the absolute least clean, and least economical, way a given car can be driven (within some semblance of reason. As in no bollards pull, brake aided burnouts nor crashing it into a military toxin factory or nuclear plant..). Then give that some serious weight in the final evaluation of “greenness”, alongside more “average” predicted ways to drive.

      • 0 avatar
        White Shadow

        Yeah, I understand the complexities of forced induction; I just can’t accept, on face value, that they are bigger gross polluters than their larger, naturally aspirated counterparts. I have seen no data to support that premise.

  • avatar

    If anyone from VW is on here, I have the solution to your problems:

    Your default engine should be a 350ci small block Chevy V8. Since you probably don’t know a ci from a quarter pounder, that’s 5.7l based on how they measure things in socialist France.

    Now, the 350ci may not fit in all vehicles. That’s okay. You can also put in a 3800cc V6, sourced from Buick. You may supercharge this if you wish, but only for the GTI.

    If neither one of those engines will fit, then it’s time to go back to the drawing board.

  • avatar
    DC Bruce

    It’s the old “teaching to the test” problem. These test loops are known quantities, so everything can be tweaked to optimize performance on the loop. In actual use, where drivers may demand higher acceleration than required on the loop, increased boost pressures will lead to higher combustion temperatures . . . and NOx formation. DI allows the use of higher compression because the injected fuel cools the air compressed into the cylinder. But DI is associated with very small particulate emission (see, diesel engines). I imagine the one real advantage of small displacement engines is that they burn less fuel idling, but start/stop can deal with that. I recently drove a rental Renault in the UK with start/stop (and a manual). It wasn’t nearly as bad as I thought it would be, although it was certainly noticeable. As we all know, in actual in the hands of just about every tester, Ford’s “Ecoboost” 4-cylinder engines achieve significantly less mileage than their EPA ratings. Then there’s the horrible example of the first generation Acura RDX, with a boosted 4 that achieved terrible fuel economy. The normally aspirated V-6 that replaced it in the second generation car actually produced substantially greater economy.

  • avatar

    I’ve been disappointed with the mileage – especially city – I get out of my ’09 Mini Clubman with a 1.6L turbocharged engine. 22-23 is pretty average for me – even dipping into 20 in winter. Even my old ’97 Volvo 850GL, which was lightly turbocharged, got that mileage and it was a heavier car.

    It’s the damn boost on the 1.6L – so easy to get into and a little addicting. It’s also the only way to get the car moving. It takes a real grandma foot to get good mileage.

    My wife’s ’03 Mini Cooper S is worse – usually 2-3mpg less mileage than me. Considering she’s only rolling 162hp in a light car, I would expect better. But that supercharger is also addicting – that engine loves to rev up to the red line.

  • avatar
    Daniel J

    Just curious, anyone know what the NOX levels are for the Mazda Sky Active Engines? While they don’t feel nor sound like the most refined things, I prefer it over the Ecoboost equivalents.

    • 0 avatar

      According to this, it’s about 7mg/km for the Euro version of the SkyActiv 2.0 6MT AWD CX-3 that we don’t get here in the states. The USDM engines run at 13:1 compression ratio while everywhere else in the world gets 14:1. Also, we can’t get a manual CX-3.

      That same website puts the SkyActiv-D 2.2 in the Mazda3 at 61mg/km and Golf GTI at 18-35mg/km, depending on transmission and power output. A Ford Fiest ST is reported as having 11-20mg/kg while the plain Fiesta w/non-turbo 1.6 emits 18mg/km.

  • avatar

    Forced induction is not a replacement for displacement, it’s a bandaid to a problem that shouldn’t exist. You can put a turbo on an 6.0L vortec, makes it better but not an 8.1L.

Read all comments

Back to TopLeave a Reply

You must be logged in to post a comment.

Recent Comments

  • Corey Lewis: I’m learning all kinds of things here, I didn’t know much about Colt at all. I remember as a...
  • Art Vandelay: This forum has got to have the largest concentration of Constitutional Scholars/Climate...
  • Corey Lewis: Really not sure why they did that with the wood. Said wood was part of the luxury Estate package.
  • Jeff S: @FreedMike–I am almost and I remember those predictions as well and yes many of them have come true. I...
  • Matt Foley: Does anyone remember a TV commercial from the late 70s/early 80s that showed a soundstage with Japan and...

New Car Research

Get a Free Dealer Quote

Who We Are

  • Adam Tonge
  • Bozi Tatarevic
  • Corey Lewis
  • Jo Borras
  • Mark Baruth
  • Ronnie Schreiber