Saturday, February 20, 2016 9:00 am ·  0 Comments
Most of us have heard about the problem with some Volkswagen diesel cars that have been fitted with a way to cheat on emission testing. This publicly surfaced on September 18, 2015 as a result of the USA Environmental Protection Agency (EPA) that issued a “Notice of Violation” – 2.0 L diesel powered cars from Volkswagen and Audi were removed from the market and no longer available for sale. This was followed in November by another EPA notice affecting 3.0 L diesel engines in Volkswagen and Audi cars. For both the 2.0 and 3.0 L engines, this problem goes back as far as 2009.
There has been little information available about what Volkswagen is actually going to do to fix the problem here in Canada. You might be asking yourself – what is taking so long? Part of the answer lies in the amount of work and money needed to have the cars meet the strict environmental regulations.
As a result of the way that many diesel engines operate, they produce nitrogen oxides (NOx), the generic term for a group of highly reactive gases, all of which contain nitrogen and oxygen in varying amounts. NOx contributes to ground-level Ozone, acid rain and many negative health issues. Car and truck manufacturers have approached the reduction of NOx emissions through two ways. Selective Catalytic Reduction (SCR) uses a urea injection method to the exhaust system to reduce NOx emissions. Apparently, because Volkswagen wanted to focus on their own “TDI” branding, they opted to develop their own approach, the NOx trap or “LNT”. Needless to say, the latter did not prove to work as well and so the “cheating software” was apparently needed. So why not solve the issue and just switch to SCR? Easier said than done.
The proven SCR approach requires that urea liquid (AdBlue) be injected into the exhaust system, turning NOx into harmless water and nitrogen. A fairly large storage tank is needed to hold the urea liquid because it gets used as you drive and so it needs to be refilled periodically. AdBlue also costs. Both the storage container and the lines feeding the liquid to the exhaust system are heated to keep the urea liquid from freezing in cold weather. Additional electrical based warning systems are in place to advise the driver of how much urea liquid is left in the tank – no different than your gas/diesel fuel gauge and low fuel warning light. For example, in Mercedes diesel cars, the urea tank sits next to the fuel tank and is large enough to only require a refill typically at oil change interval times. Finally, the exhaust system components, including the catalytic converter are somewhat different, and can be more expensive.
In order to put a urea based system into the 2.0 L and 3.0 L cars presently equipped with VWs “LNT” system, space would need to be found for a sufficiently large urea tank; additional feeder lines installed; an electrical heating and “low tank” warning system added; as well as additional physical component changes to the exhaust system. Needless to say, this retrofit is very likely to be both too expensive and time consuming for many of the older Volkswagen and Audi cars.
It is also likely to reduce the performance and fuel efficiency. In other words, a complete retrofit is highly unlikely for some of these. In addition to the many VW and Audi diesels already sold and on the road, it leaves VW with another vexing problem of what to do with all of the unsold diesel 2.0 L and 3.0 L 2015 cars sitting in their lots? Might it be cheaper just to crush them, as some have suggested? Mercedes announced in early February that they are investing 2.6 billion euros to introduce the SCR system with Adblue injection units on its smaller front wheel drive compact cars by 2019. They have clearly seen the limits of the NOx trap system.
Meanwhile in Europe, VW has received approval to fix the problem with its 1.2 L, 1.6 L and 2.0 L engines. The “fix” is largely a software upgrade, an additional filter to trap particulates and in some cases, an airflow change to improve engine filter efficiency. Of course, this is only to make the cars “Euro 5” emissions limit compliant. This emission limit is greater than that allowed by the EPA which may explain why VW is not getting very far resolving this issue in the USA.
On January 12, 2016, The EPA Air Resources Board rejected VW 2-liter diesel recall plan (deemed incomplete) and issues yet another Notice of Violation. A plan for the 3.0 L has been submitted by VW to the EPA in early February – awaiting decision. What this all means for Canada remains to be seen. Both owners as well as VW and AUDI dealers continue to wait.
2.0 L Engines, 2009, 3.0 L Engine, acid rain, Audi, catalytic converter, Diesel Engines, EPA, EPA Air Resources Board, ground-level Ozone, January 12 2016, Mercedes Benz, negative Health Issues, nitrogen oxides, NOx, Selective Catalytic Reduction, September 18 2015, TDI, urea liquid, USA Environmental Protection Agency, Volkswagen