I believe the new Jetta TDI will require it in the US, and the Passat already does. It is possible to reach current US NOx limits without using SCR and DEF. The previous Jetta did so, but relying on EGR and a NOx trap alone to do so results in fuel economy loss. The non DEF Jetta wasn't rated much better than the DEF Passat.
With the less stringent emissions, the penalty from EGR and/or a NOx trap alone in Europe isn't as great as it is in the US. The US is also moving to Tier III emissions. Some of the diesels are already certified to it here. Those that are all use DEF. Some of them could be certified to ULEV or even SULEV under the current system.
I track my DEF use as a maintanence item like an oil change. I use aCar on my android. I have a 2013 F350 purchased new with 20 mile on the odometer. First time I added DEF was at 6k right before first oil change. 5 gallons were added. After that I began to use a fuel additive called Diesel Mechanic in a Bottle. I add 4 oz per fill up about 1oz per 10 gallons. After using additive, the next time I addes DEF was at 14k miles. The next time was at 23k and the last time I added was about 32k. All in all I got 6k on fill up from the dealer, them about 8k, 9k, and 8k after using the fuel additive. I don't think tracking miles per gallon on DEF is a big deal to most, everyone I have spoken to about DEF say they just add 2.5gallons when the light comes on. I am not sure if the additive has increased milage or not on my vehicle. Total mpg is 12.798 with 105 fill ups and 2787.46 gallons. Best of 16.69 mpg worst of 9.612 Mostly city driving pulling a trailer about 25%. I have had a few customers that have reported milage increases on older trucks and cars.
Personaly i've never heard of any kind of additive for any diesel vehicle, personel or commercial until I joined Fuelly. I think this is another strange US only thing...
LOL! another strange US thing....hahaha, like the strange catalytic converter that we had to have by 1975 but while I was living in germany in the early 90's saw all these cars with "mit catalyst" in the back windows in green and them bragging how green germany was as their cars now had catalytic converters, lol, yeah, DEF is another "strange US thing" lol.
And by the way, 2007 was the year you couldn't by a vw diesel here because the euro model couldn't meet the N/A emissions tests. VW scrambled for a bit and late 2007-2008 came up with a solution for the 2008 model year.
Yea the US has been blaming "emissions standards" for a reason to keep diesels out for decades. In my opinion, it's because the US economy relies too much on the sale and consumption of oil and gas, if they all had cars that only used a gallon of fuel every 80 miles, and changed their oil every two years, their economy would crash big-time. Just my theory for what it's worth!
Smog and diesel pollution is only a problem in a couple of overcrowded cities. If you cram the entire population of Australia into one city, it's inevitable there's going to be problems. Modern diesels filter 99.9% of particulate now, and don't forget, although they emit Nitrous oxide, petrol powered cars still emit more C02, more carbon monoxide, and hydrocarbons too, so don't go thinking a city full of petrol cars is healthy. I didn't say my car gets 80 MPG dude, I said if America had cars that did 80 Mpg, please read correctly if you want to pull me up on things.
And I need not remind you I'm entitled to my own opinions and theories, and it's ok to discuss or disagree