Real World Emissions Testing May Lead To Larger Engines


Blame it on Volkswagen. Until the diesel emissions cheating scandal broke more than a year ago, the world of automobiles was cruising along, serene in the knowledge that emissions testing protocols were doing a pretty good job of protecting us from cars that pollute the environment. Then the world shifted on its axis and we found, much to everyone’s dismay, that emissions testing in the lab is worthless when it comes to measuring real world performance.

real world emissions testing

In order to meet increasingly rigorous emissions regulations, automakers for years have been downsizing the engines they use. V-8’s became V-6’s. 4 cylinders became 3 cylinders. Fiat and some other manufacturers started offering 2 cylinder engines in some models. The trick was to add turbochargers to the smaller engines to make up for the decrease in displacement.

In theory, the smaller engines would perform brilliantly in emissions testing performed in laboratories using dynomometers computer simulations. That part turned out to be true. But when Dieselgate came along, it made people realize that those emissions testing protocols were worthless when it comes to measuring performance in real world driving situation.

The discrepancy was particularly noticeable with diesel engines. The smaller the engines got, the higher their real world emissions. Apparently the extra heat created by adding turbochargers causes NOx emissions to soar to levels as much as 15 times higher than measured in the lab. The smaller gas engines have issues, too. They become less fuel efficient in real world driving. Worse, they tend to spew particulates out the tailpipe along with increased amounts of carbon monoxide.

“They might be doing OK in the current European test cycle, but in the real world they are not performing,” said Pavan Potluri, an analyst with influential forecaster IHS Automotive. “So there’s actually a bit of ‘upsizing’ going on, particularly in diesel.”

The European Union is about to make real world emissions testing mandatory and that is causing a kerfluffle in the industry. “The techniques we’ve used to reduce engine capacities will no longer allow us to meet emissions standards,” said Alain Raposo, head of powertrain at Renault-Nissan. “We’re reaching the limits of downsizing,” he said at the Paris auto show this month.

The tougher real world tests may kill diesel engines smaller than 1.5 liters and gas engines below about 1.2, analysts predict. That in turn increases the challenge of meeting CO2 goals, adding urgency to the scramble for electric cars and hybrids. The issue is less serious in North America and China, where the push to downsize engines has not reached the levels seen in Europe. But it does show that going smaller and bolting on a turbo is not the magic solution some thought it was.

What may work, however, is marrying smaller engines to electric motors to create a powertrain that meets the needs of motorists and the environment. In a curious way, the troubles at Volkswagen may actually end up making electric cars — or partially electric cars — more common in the marketplace.

Source: Reuters  Photo via Hybrid Cars

About the Author

I have been a car nut since the days when Rob Walker and Henry N. Manney, III graced the pages of Road & Track. Today, I use my trusty Miata for TSD rallies and occasional track days at Lime Rock and Watkins Glen. If it moves on wheels, I'm interested in it. Please follow me on Google + and Twitter.
  • kvleeuwen

    What a waste of R&D resources… then, and now again.

  • topkill

    And the Saudi’s have changed their tune and now OPEC has limits coming so oil prices will start to rise again.

    Electric cars will start to accelerate in every way. That inflection point is starting to come more and more quickly.

  • kevin mccune

    So we have hit the “barrier ” again .

  • JP

    If you own an EV, PLEASE beg people to hop in the driver’s seat. The more people that drive EVs and learn their benefits; the more EVs will take over the roads. The general population do not understand how they work. As an owner, you wonder how that is possible; but I assure you, people don’t understand them. I am an Uber driver that explains the Chevy Volt EVERY time I drive. Few riders know how EVs work and even less understand how a EREV (extended range electric vehicle) works. Once a rider sees my Volt screen, the questions start rolling. I can’t educate the whole planet by myself, but the EV community owes it to ourselves to spread the knowledge of EVs for our own sake, but ESPECIALLY for the sake of our children and grandchildren. An article like this is EXACTLY what 99% of the auto industry will you to tell the people that emissions regs are unachievable and should be lowered. We the EV community know that ALL vehicles could be electrified today. Not in 20 years or 10 years or even have to wait 5 years. TODAY! If the public stops buying gas cars, the industry will stop making them. Not the other way around. I am aware of how long winded this has become. I just want “we the people”, the ones in the “know” to see that once one has changed the man in the mirror, he or she must set their sites on others. I have personally felt some of your pains. I have convinced some of my friends to join the good side of the force, but not a SINGLE family member. Unless you count brother-in-law. He was driving a turbo diesel truck to work until I convinced him to lease a Nissan leaf for less than the cost of fuel per month. One person at a time, BUT all the time. The new ABC. Always Be Connecting. Not just your plug, but people. Connect with others to share your EV experience. thank you for reading.
    EV ON!!!!!

    • Steve Hanley

      Thanks for that impassioned plea. We at Gas2 are doing everything we can to get the word out.

      Your comment puts a spotlight on just how poor a job the car companies are doing of getting the word out. It is possible they don’t want people to know?

    • James Rowland

      I greatly appreciate your passion in writing this and especially your working to raise awareness of EVs with your Volt. This kind of viral consciousness raising is perhaps our best hope for rapid public acceptance of EVs.

      However, may I respectfully urge you to learn more about paragraphs and what they can do for the readability of your text?

    • Diego Matter

      I agree with you that we have to educate and that electric vehicles are here today. But there is one catch in Australia – the price. The Volt was over AU$ 50’000. The Leaf over 40’000.
      I don’t even argue about range. The new versions have all enough range – but again, they are not yet sold in Australia.

    • Miles Harding

      Someting that electric car clubs can do.

      In Wesstern Australia, the AEVA runs annual event called “Electrikhana”, where the general public are invited to a test track to come and try EVs for a nominal cost ($10). Drives of most members cars are available, as well as rides in some members’ Teslas. None of the Tesla owners are willing to let the loony public loose in a 700 HP car.

      This is generally well patronised and can introduce EVs to 500 or more people in a single day.

  • Rick Danger

    Real world emissions testing should lead to outlawing the manufacture of ICEs by 2020.

  • James Rowland

    Good to see that the time is finally up for gaming the old, broken emissions test protocols. This came about twenty years too late though.

    I’ve long been of the opinion that undersized engines were a bad idea, given how they’re run at high throttle more often than a larger engine would be in real driving. Everything about ICE efficiency and cleanliness goes south when you open them up wide.

    Of course, it’s far better to throw all that junk out and use electric motors instead. Hopefully, we’ll predominately be doing that before cars qualified under these new tests have replaced much of the existing fleet. They won’t be good, just less awful.