DEF fluid is dead!

[brokcanadian]

Along with the pollution control breakdowns that afflict newer Sprinter and others.

This hit me sideways, it's from a manufacturer that I made a complete break with, old or new vehicle (a junior tech forgot to fill the antifreeze in our MPV at a recall service, we were phoned to come pick it up, then arrived to be told it needed an engine)

So...diesel engine with no pollution controls, available later this year

After 100 Years, Internal Combustion Still Has a Few Surprises

MAZDA: SKYACTIV-D | SKYACTIV TECHNOLOGY

Everybody, Ford Ram Mercedes needs to license this

 

[piper1]

Sorry....nope.

Mazda's engines do not meet EPA rules without SCR (DEF system that targets Nox). EPA Nox rules are still tighter than the Euro rules...largely thanks to California's meddling.

The Sky activ engines also use an internal form of EGR...sort of a Miller cycle principle....CAT tried that with its ACERT engines....and has since exited the on highway engine business because it....well it didn't go to well.

How Mazda solved its diesel dilemma

The Cali emissions regime (and by proxy alot of the EPA) just plain hate diesel engines...and by pursuing Nox and particulate emissions as thier main goals (when you fix one it makes the other worse) they know eventually they can make diesels very costly/unreliable/poor peformance/not worth building. Some might argue that we're almost there.

 

[brokcanadian]

They said it will be out in US by September. Are they wrong?

Hmm that autoweek article mentions compact SCR. I'll have to research more

Didn't they have an oilfield fire in California that burned for months? And they're worried about a handful of diesel vans?

Edit: after scanning the info in that diesel (9 out of 10 articles making no mention of SCR) it appears that they tacked on DEF to solve the US emissions problem. They missed the pollution target by 0.01 grams per mile or so

 

[piper1]

it appears that they tacked on DEF to solve the US emissions problem.

Therein lies the rub. Just about every world diesel won't meet the US rules for Nox..without SCR/DEF..been this way since 2007. Missing it by 0.01 grams is actually quite a bit when the limit to start with is 0.2g...and the next hurdle (again thanks to California) is 0.02g.

Just to give people an idea of how low these rules are..a DPF on a Sprinter....needs to re-gen after capturing less than ounce (28g) of soot. And it takes the average Sprinter at least 400 miles to make that little amount. And if you make an engine make less soot..it automatically makes more Nox. Nox is generated in a very lean, hot and otherwise clean low soot and fuel efficient burn. You lower Nox with EGR (and that creates soot) or SCR/DEF that...despite the headaches it causes is actually the better way to do it for fuel mileage and engine life as it does not require messing with the actual combustion in the cylinder. CAT, International and Volkswagen all tried to go the no DEF route...Cat doesn't make on highway engines any more because they couldn't do it...and International almost went bankrupt trying to make their Maxxforce engines do it...as hard as they tried..it never worked (and the engines were total disasters) and Volkswagen...well we all know how that turned out.

 

[coalminer]

Therein lies the rub. Just about every world diesel won't meet the US rules for Nox..without SCR/DEF..been this way since 2007. Missing it by 0.01 grams is actually quite a bit when the limit to start with is 0.2g...and the next hurdle (again thanks to California) is 0.02g.

Just to give people an idea of how low these rules are..a DPF on a Sprinter....needs to re-gen after capturing less than ounce (28g) of soot. And it takes the average Sprinter at least 400 miles to make that little amount. And if you make an engine make less soot..it automatically makes more Nox. Nox is generated in a very lean, hot and otherwise clean low soot and fuel efficient burn. You lower Nox with EGR (and that creates soot) or SCR/DEF that...despite the headaches it causes is actually the better way to do it for fuel mileage and engine life as it does not require messing with the actual combustion in the cylinder. CAT, International and Volkswagen all tried to go the no DEF route...Cat doesn't make on highway engines any more because they couldn't do it...and International almost went bankrupt trying to make their Maxxforce engines do it...as hard as they tried..it never worked (and the engines were total disasters) and Volkswagen...well we all know how that turned out.

Exactly, as bad as def/scr is, it's the best way to reduce nox emissions on diesel engines.


Now I do think that there should be exemptions for certain vehicles, like rvs which do a lot of sitting and very little driving. Def systems work well on vehicles like otr trucks that run at highway speed most of the time, as long as the engine is shut down at night instead of idling all night.


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[beachbum]

I'm I wrong but they don't have all these problems with DEF in Europe only the US. Makes you wonder if it's the EPA that's causing the problems with their rules.

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