After diesel exhaust passes through the oxidation catalyst and a particulate filter, diesel exhaust fluid (DEF, branded by VW as AdBlue) is injected into the stream before entering the reduction ...

How much power and efficiency goes away--and how well owners would accept those tradeoffs--remains to be seen. (2) Use more AdBlue fluid For those vehicles fitted with Selective Catalytic ...

"I headed off to the VW dealer to get some AdBlue. The parts guy didn't know how much to sell me, so I bought one half-gallon container for $16. They also had a 2.5-gallon jug for $30 -- obviously ...

"The new diesel engine uses twin dosing, which features SCR catalytic converters and a twin AdBlue injection process to reduce nitrogen oxide (NOx) emissions by up to 80%," Volkswagen notes.

Second, Volkswagen intends to make sure that diesel emissions will not be an issue in the future, especially in the face of greater attention from regulators in Europe and in the U.S.

Typically, a Volkswagen Passat TDI uses around 1.5 litres of AdBlue every 620 miles, and the tank size is 13 litres, so a full tank of AdBlue is good for about 8000 miles of driving.

The worst off is the VW Sharan built between 2010 to 2015 - 70,000 units that have the 2.0 TDI making 115, 140, 170 and 177 PS.