So, when you are trying very hard to make engines more efficient to get impressive mpg numbers, you also end up generating more NOx (Which you can then get rid of using urea, which I think is the preferred option in trucks and buses - think AdBlue or whatever it is called when used for cars.
However, at least around here they sell it at (some) gas stations, and the user manual (2012 Passat 3c) shows how you go about topping it up, so it can't be that much of a concern.
I strongly doubt that there is a significant cultural difference between the two, in terms of car culture.
My blotto California brain went 'no! no one is touching my car!'
Well, they don't sell well in the US, but they didn't sell well prior to DEF, so I don't think you can pin the blame on that.
- You can let the tank go empty and not turn up to the workshop for the fill up, how does disallowing to top it up yourself prevent that?
- Many current cars with AdBlue will flash increasingly annoying warnings at you, and although many people drive with check engine lights lit, running out of urea will display you a counter of remaining kilometers and the car will simply refuse to start when empty. Again, nothing to do with whether you push the car to the dealership on foot or fill the tank yourself from the bottle (and actually, there are very foolproof anti-spill bottles, which let the liquid go only when tightly screwed onto the DEF tank).
Yes it does, since it affects the design of the vehicle. Remember that the context of this thread includes:
"So the tank needs to be large enough to cover a full maintenance interval...or creative solution to limit consumption."
If it's really a question of forcing people to refill the tank you could have the engine refuse to start if the tank is empty.
There are more fundamental issues though, the car needs to not run if it's empty, a lot of people drive around with their dashboard lit up and don't care. People will balk at having a full tank of gas and the car shuts down because of DEF.
I've never seen any warning or notice stating that it should not be filled by owners. I have a diesel VW and refilling the tank is pretty easy. The dealer didn't have any qualms selling it to me.
There's an idiot light type indicator that tells you when the change is coming up, just as with oil changes, and if ignored I think the engine will go eventually go into a kind of limp mode.
This all sounds to be entirely due to inadequate emissions testing processes and manufacturers doing the absolute bare minimum to comply with those tests as if they're gaming the rules of an automobile race.
Obviously, it would soot orders of magnitude more - but I wouldn't be surprised if the NOx emissions were surprisingly low, seeing as efficiency was way down on Toyota's list of requirements; they just made a bigger fuel tank.
It was designed to just work(tm) - almost regardless of what happened to it. Gas mileage? Not as much.
However it does consume more AdBlue and/or produces less power the cleaner it is
They did it to sell a "better car" with disregard to pollution regulation
This is why it's more costly. In order to design a diesel car that meets the exact same specifications, they either need to add an entire urea system (costs more money to manufacture, plus ongoing AdBlue costs to the consumer) or add a larger less efficient engine to meet the same performance target (costs more money to manufacture, plus ongoing higher petrol costs to the consumer).
Making a non-polluting diesel car is certainly more costly than making an equivalent diesel car that you don't care about pollution on at all. You're adding a big engineering constraint, of course it gets more costly!
I should add that I'm all in favor of cutting down pollution, and that if diesel as a technology turns out to not be that practical anymore for small cars, then so be it. Eventually they should all be zero emissions anyway.
This is tricky because, in the US market at least, one of the major appeals of small diesel cars was their performance / low end torque. There aren't really any other options on the market right now that can offer the same mix of performance/efficiency. Diesel cars are definitely on their way out in the US but I'm not sure it will be a net gain in the end. Lots of people such as myself are choosing to replace their small diesel cars with bigger, less efficient, similar performing cars.
Friend of mine is ditching his VW Diesel TDI for a Chevy Bolt at the end of the month. I'll be interested to see what he makes of that switch. Electric has if nothing but low end torque.