cmc said:
well things like 3 way cats on gassers have to
be tested and shown to be able to last 100K before
they get a pass right? no doubt some will fail before
then but then the EPA also requires that the warranty
cover them. i can see why urea injection doesn't pass
because the urea supply is a consumable and the system
as a whole simply would not last 100K
It runs a little deeper than that, because while the EPA can mandate warranty coverage they can't really control what owners do with the car - what fuel they use, what maintainence work they do, etc.
A catalytic converter is covered by a warranty by the manufacturere for something like 120,000 miles or 10 years, and that warranty extends to a lot of components of the exhaust treatment system. If it breaks or malfunctions before that deadline the manufacturer is obligated to fix it under that warranty.
The wrench that gets thrown into the works is if the customer misfuels the vehicle or doesn't do required maintainence. If a gasoline vehicle is taken on a trip to Mexico and filled up with leaded gasoline a few times (I'm not even sure if leaded gas is still sold in Mexico), that is something that is not covered by that warranty. The manufacturer doesn't have to fix any exhaust emissions equipment that is broken or rendered ineffective because of the owner of the vehicle.
Modern cars with OBD-II diagnostics illuminate the Check Engine Light for any number of faults, including some minor things as simple as leaving the gas cap loose after a fill-up. The EPA requires that vehicle owners get their emissions system fixed as promptly as possible, but I'm sure you see plenty of cases each day where people ignore these requirements. Places that have smog checks on a regular basis usually don't even test a car if the CEL is illuminated. Places that don't - well, that's an even bigger incentive for people to ignore that CEL if their car is otherwise running fine.
There is no car that shuts the engine off or refuses to start when the CEL is illuminated because cars are essentially dumb. Along with perfectly good reasons for the CEL to come on, there are also times when it lights up for no good reason. Every computer system has glitches, no matter how much testing and refinement is put into it. Customers would be furious if their car refused to start because the government got to the business of deciding that a car shouldn't run when it's CEL is light. With something like that, then the customer would have to pay for a tow truck to take it to a service center. And if the CEL just needed a simple reset for some odd-ball fault there would be even more fireworks from people inconvienenced with a non-running car, a tow bill, a diagnostic bill - only to tell them their car is fine and has nothing wrong with it.
Keeping this in mind, that's the reason that any new diesel vehicle with urea-injection shouldn't be hampered with any disabling features for an empty urea tank. An empty urea tank is an emissions fault that is a problem with the owner not doing required maintainence. Just the same as any gasser owner can ignore a CEL when their catalytic converter stops working, a diesel owner shouldn't be stuck in the breakdown lane when they run out of urea. Both times, the EPA expects owners to correct the fault on their own - get their cat replaced or fill up the urea tank. As long as instructions are in the operators manual, the EPA can hope for the best - and have fines for people that don't comply. Just like there are big $$$ fines for messing with catalytic convertors, they can have them for diesel owners who don't fill up the urea tank. Enforcement of these fines are another thing entirely . . .
Getting even more detailed about urea injection, I'm going to speculate that the Magnussen-Moss Act of 1978 might come into play with VW failing to adopt urea injection. If VW equips any of their future TDI models with urea injection, they're going to have to worry about supplying urea refills to the owners. In order to maintain the EPA warranty on exhaust treatment equipment, VW will want to have a good amount of control with that urea supply to ensure that TDI owners are getting good quality urea fluid that works with the urea injection. I don't know if they will open their specifications for urea fluid to third-party vendors, and even if they do there is no guarantee that anyone will be making this stuff to stock on the shelves at Auto Zone.
So in that respect, VW might just have to pull their TDI from the market and not adapt urea injection for fear of warranty repercussions. VW will want to absolutely ensure that good urea is available to customers and used properly to make sure that they don't have future warranty claims that could cost VW big money. If VW is the only seller of their own special branded urea refills, and requires these refills to maintain warranty coverage, then they'd be obligated to provide said urea refills for free to customers on demand. This would also cost big money - likely more than they'd make selling the cars.
Between the devil and the deep blue sea. Facing a choice between worrying about warranty costs with improper urea refills, or worrying about providing free urea refills to comply with Magnussen-Moss, VW might just choose option number 3 and not sell TDI cars in the North American market - at least until the people at the EPA pull their heads out of their a$$es and ease up on those emissions standards for diesels. I can possibly see some serious tension put on the EPA in the next few years. The EPA themselves put out statements like "The USA would save all our oil imports from Saudi Arabia if 33% of the vehicles in the USA were diesel powered" and then turn around and essentially set huge hurdles for diesel vehicles to jump over to make it to market. Give it another record setting year of high fuel prices, and I'll bet some people twist a thumbscrew in the right places to get the EPA to change some things.