Yup - just when you thought it could not get any better - from c|net Road Show:
Oh, not again: US reportedly finds new secret software in VW diesels
It looks like Volkswagen's diesel scandal could keep rolling as reports claim that the automaker has three hidden software programs in its 3.0-liter engines.
Concerns about the German car manufacturers' 2.0-liter engines could soon reach a conclusion, but the discovery of the hidden software has thrown the future of 3.0-liter diesels into uncertainty.
That secret software in Volkswagen's 3.0-liter diesels can turn off the vehicles' emissions controls, Reuters reports, citing the German newspaper Bild am Sonntag. The emissions control system allegedly shuts off after 22 minutes, when most emissions tests take about 20.
If this software does exist, it likely resides in all 3.0-liter diesels that Volkswagen sells in the US. This includes the Audi Q7, Volkswagen Touareg and Porsche Cayenne SUVs. Approximately 85,000 of these cars are roaming around the US, and they're already under scrutiny for some software that VW "forgot" to tell regulators about.
"We continue to work closely with the EPA and CARB to try to secure approval of a technical resolution for affected vehicles with 3.0L V6 TDI engines as quickly as possible," Audi said in an emailed statement. "As stated in today's Court hearing, an updated proposal is undergoing thorough testing and analysis and we intend to submit this to the regulators in August. The Court has instructed the parties to report on the status of these discussions on August 25."
A damn shame as I really like the design of the TDI diesel. They should have gone with a Diesel Exhaust Fluid / Selective Catalytic Reduction system like larger trucks have (mine included). A wee bit more hassle but a much better performing engine and much cleaner emissions. Instead, they chose to use software trickery and they got caught.
The Diesel Exhaust Fluid system is quite clever - from Wikipedia (and more here too):
Diesel engines can be run with a lean burn air-to-fuel ratio (overstoichiometric ratio), to ensure the full combustion of soot and to prevent the exhaust of unburnt fuel. The excess of air necessarily leads to generation of mono-nitrogen oxides (NOx), which are harmful pollutants, from the nitrogen in the air. Selective catalytic reduction is used to reduce the amount of NOx released into the atmosphere. Diesel exhaust fluid (DEF) from a separate tank is injected into the exhaust pipeline, where the aqueous urea vaporizes and decomposes to form ammonia and carbon dioxide. Within the SCR catalyst, the NOx are catalytically reduced by the ammonia (NH3) into water ( H2O) and nitrogen (N2), which are both harmless; and these are then released through the exhaust.
In a word: more optimized combustion, better fuel efficiency, increased power, reduced maintenance, fewer regenerations, less wear on the engine, plus it yields harmless nitrogen and water into the atmosphere, and it's highly reliable.
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