Emissions fix could hurt VW vehicles’ performance

Before its emissions-rigging scandal came to light, Volkswagen AG poured a lot of effort into changing the North American perception of diesel as smelly, dirty and loud. Along with other European automakers, VW touted a new era of “clean diesel,” arguing it was possible to have the performance of a diesel engine without the pollution.

We now know Volkswagen had been rigging emissions tests for years and that some of its cars were spewing many times the legal limit of nitrogen oxides (NOx).

But this doesn’t mean clean diesel is a myth, said Ming Zheng, director of the Clean Combustion Engine Laboratory at the University of Windsor.

“What we can achieve nowadays was considered impossible 10 years ago,” he said. “It’s very difficult and very complicated, but the industry is making progress. It’s not just marginal — it’s a tremendous amount of progress.”

According to science news site Live Science, Volkswagen responded to the challenge of reducing nitrogen-oxide emissions by developing a sort of “trap” that absorbed NOx like a sponge. When the trap was full, the system would inject fuel that would neutralize the NOx. However, this may have hurt fuel efficiency and performance, causing Volkswagen to resort to cheating on emissions tests.

Other automakers, including Mercedes-Benz, use a different kind of technology called Bluetec that uses urea to reduce NOx emissions. According to Live Science, this doesn’t affect fuel economy or power, but it does require a separate tank for the urea which must be refilled occasionally.

There’s another issue with the Bluetec technology that’s particularly problematic in Canada, said Zheng — the urea solution is a water-based solvent that freezes when it’s cold outside.

Unlike the smelly pollution that diesel is traditionally associated with, nitrogen oxides are colourless, odourless gases, but can cause serious respiratory problems.

“One of the ironies of this is that the biggest problem historically about diesel has been the particles, the soot that comes out of it,” said Daniel Greenbaum, president of the Boston-based Health Effects Institute and chairman of the International Council on Clean Transportation.

“All these new diesels have filters on them and the irony is that, although the Volkswagens have problems with nitrogen oxides, they actually met the standards for particles.”

The question now for Volkswagen is how best to fix the vehicles that were built with so-called “defeat devices.”

One way would be to update the software so the pollution-control systems are always on, but there is a trade-off between performance and emissions, Zheng said.

“The tightened emission control would lower fuel efficiency very much, by 10 per cent or so, for every kind of engine, not just for diesel or for Volkswagen,” he said.

This is not making Volkswagen customers happy.

Ottawa resident Pierre Roy recently bought an Audi Q5 — Audi is owned by Volkswagen — and is worried that his vehicle could be swept up in the scandal.

The U.S. Environmental Protection Agency has only identified four-cylinder Volkswagen and Audi diesel cars from model years 2009 to 2015 as the culprits. This doesn’t include the Q5, a six-cylinder, but Roy said he wants to be assured that his vehicle isn’t equipped with the same defeat device.

“I need to be convinced by someone that my three-litre, six-cylinder (engine) is somehow not part of this conspiracy,” said Roy.

He said he and his wife chose to spend an extra $3,000 on the vehicle because of its smaller environmental footprint.

“I am not interested in keeping a vehicle that is bad for the environment, and am not interested in a modified vehicle that reduces performance, fuel economy or longevity,” Roy said.