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> Filling it takes 5 minutes once every 1-2 years Isn‘t this a part of the problem? The urea tanks are way too small and need refilling way too seldom which me

by junga 8y ago

> Filling it takes 5 minutes once every 1-2 years Isn‘t this a part of the problem? The urea tanks are way too small and need refilling way too seldom which means a too low urea usage? Volkswagen wanted urea to be refilled by your service station and not by the customers themselves because they might have found this inconvenient.

Reason077 8y ago
Exactly. If it's only being filled with (eg) 8L every 1-2 years, then it's not being used much and is probably not very effective at reducing NOx emissions. Depending on the engine, driving style, etc, it should really be using something on the order of 20-60 litres of AdBlue per 1000 litres of diesel.
alkonaut 8y ago
My last car was a diesel-gate car (09 Audi) which didn’t have a Urea tank at all. I know VW managers first thought Urea was an inconvenience to have at all, then an inconvenience for owners to refill so should last a service interval. My new car has a Urea tank and isn’t a diesel-gate car. It need to refill maybe 1 time before the service intervals. I can’t see why it would be considered inconvenient - it’s easier to refill than windshield wiper fluid (that you need to pop the hood for!). So if it would have come at a price of 20L diesel capacity space, and require refills every month, I still wouldn’t have found it inconvenient. I don’t know how they determine how much AdBlue to consume now, but I’m guessing since they now manage to comply with regulation they just use as little as possible? If they can further limit emissions by using more, then there’s some headroom for improving too.
makomk 8y ago
The problem wasn't just that it was an inconvenience. Under the EPA rules of the time, urea refills were considered critical emission-related maintenance. Initially, this meant that they had to last 100,000-150,000 miles unless the EPA gave a waiver allowing more frequent servicing intervals.[1] This wasn't physically feasible. A couple of years into Dieselgate, they decided they'd allow DEF refills at the oil change interval, which still required much larger tanks than the European models (typically replacing the spare tyre) or cheating.[2] It wasn't until mid-2014 that they decided users could be allowed to refill their own urea tanks and lowered the minimum DEF refill interval for cars to a slightly more reasonable 4,000 miles.[3] [1] https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=16677&flag=1 https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=16677&... [2] https://www.govinfo.gov/content/pkg/FR-2009-11-09/pdf/E9-26924.pdf https://www.govinfo.gov/content/pkg/FR-2009-11-09/pdf/E9-269... [3] https://www.govinfo.gov/content/pkg/FR-2014-08-08/pdf/2014-18738.pdf https://www.govinfo.gov/content/pkg/FR-2014-08-08/pdf/2014-1...

by junga 8y ago

Reason077 8y ago

Exactly. If it's only being filled with (eg) 8L every 1-2 years, then it's not being used much and is probably not very effective at reducing NOx emissions. Depending on the engine, driving style, etc, it should really be using something on the order of 20-60 litres of AdBlue per 1000 litres of diesel.

alkonaut 8y ago

My last car was a diesel-gate car (09 Audi) which didn’t have a Urea tank at all. I know VW managers first thought Urea was an inconvenience to have at all, then an inconvenience for owners to refill so should last a service interval. My new car has a Urea tank and isn’t a diesel-gate car. It need to refill maybe 1 time before the service intervals. I can’t see why it would be considered inconvenient - it’s easier to refill than windshield wiper fluid (that you need to pop the hood for!). So if it would have come at a price of 20L diesel capacity space, and require refills every month, I still wouldn’t have found it inconvenient. I don’t know how they determine how much AdBlue to consume now, but I’m guessing since they now manage to comply with regulation they just use as little as possible? If they can further limit emissions by using more, then there’s some headroom for improving too.

makomk 8y ago

The problem wasn't just that it was an inconvenience. Under the EPA rules of the time, urea refills were considered critical emission-related maintenance. Initially, this meant that they had to last 100,000-150,000 miles unless the EPA gave a waiver allowing more frequent servicing intervals.[1] This wasn't physically feasible. A couple of years into Dieselgate, they decided they'd allow DEF refills at the oil change interval, which still required much larger tanks than the European models (typically replacing the spare tyre) or cheating.[2] It wasn't until mid-2014 that they decided users could be allowed to refill their own urea tanks and lowered the minimum DEF refill interval for cars to a slightly more reasonable 4,000 miles.[3] [1] https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=16677&flag=1 https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=16677&... [2] https://www.govinfo.gov/content/pkg/FR-2009-11-09/pdf/E9-26924.pdf https://www.govinfo.gov/content/pkg/FR-2009-11-09/pdf/E9-269... [3] https://www.govinfo.gov/content/pkg/FR-2014-08-08/pdf/2014-18738.pdf https://www.govinfo.gov/content/pkg/FR-2014-08-08/pdf/2014-1...