Exhuast fluid

[chart1]

I was at a truck stop the other day and seen they were selling exhuast fluid. I have never seen it before. What is it used for?

[Timkar]

At first I thought it might be the same thing as when I was in Navy and we used to send the "newest" recruit to get some red oil for the port running light...... but apparently not:
http://green.autoblog.com/2009/03/10/i-pickuptrucks-com-i-looks-at-diesel-exhaust-fluid/

[JohnEd]

Tim,

Thanks.  Very interesting.

John

[Busted Knuckle]

It's for new fangle high dollar coaches w/2010 and newer engines!

I doubt any of us here will be worrying about it for a while!
  BK 

[belfert]

It is urea that is used to clean up the exhaust on 2010 and newer diesel engines.  There is a seperate tank for diesel exhaust fluid on new vehicles.  Even new diesel pickups use DEF except the Cummin 6.7 in the Dodge Ram.

[Busted Knuckle]

It is urea that is used to clean up the exhaust on 2010 and newer diesel engines.  There is a seperate tank for diesel exhaust fluid on new vehicles.  Even new diesel pickups use DEF except the Cummin 6.7 in the Dodge Ram.

Yeah what Brian said! When Booger & I went to Setra's training course in Salt Lake they spent a 1/2 a day on it w/us but I kinda ticked off the instructor when there was no way I was plumbing my holding tank into the exhaust just to please the Guvenmit!
  BK 

[Van]

And I thought it was for the muffler bearings in an ol Henway.

[TomC]

Except for International, all engine manufacturers-including MAN in Europe that supplies International with their Maxxforce 11 and 13 liter engine-are use DEF.  It is a mixture of 32% ammonia and distilled water.  The exhaust is so clean that many trucks that I'm spec'ing out, I am installing horizontal exhausts.  It saves about 150lbs and about $400.00 over the old style up exhaust stack.  Plus the fuel mileage these new trucks are getting-we're seeing some 80,000lb trucks getting over 8mpg.  Now that's efficient!  Good Luck, TomC

[Sean]

...  It is a mixture of 32% ammonia and distilled water.  ...

Actually, Brian had it right, it is urea, 32.5% by the MSDS.

Urea is highly soluble in water but easily dissociates to ammonia, which is released as a gas and is the principle component of urea's distinctive odor.  It is this ammonia, released by the hydrolysis of the urea, that becomes a reagent in the selective catalytic reduction reaction that occurs downstream in the catalytic converter.  The ammonia then reacts with oxides of nitrogen in the exhaust to produce harmless water and gaseous nitrogen.

Urea is neither acidic nor basic and therefore will not corrode the metal components of the exhaust system and is relatively safe to handle and store.  By contrast, ammonia is highly caustic and would eat through the exhaust system in short order.  It is a strong base and harmful to human skin, eyes, and membranes.

DEF only reduces nitrogen oxide emissions, which are colorless and generally odorless emissions.  Soot is reduced separately in a particulate filter.  Almost none of the clean exhaust technology would work at all, however, if it were not for the very tightly controlled combustion process which is electronically regulated and incorporates feedback from exhaust sensors.  Ensuring that only the fuel which can be completely combusted on any given stroke is injected into the cylinder reduces the workload on the filters, and also improves fuel mileage.

-Sean
http://OurOdyssey.BlogSpot.com

[Chopper Scott]

They are in farm tractors, combines and industrial engines also. I'm hearing the fluid isn't real cheap but I have no idea how long it lasts or such. So if you run out of the urea fluid does that stop the engine?

[Sean]

They are in farm tractors, combines and industrial engines also. I'm hearing the fluid isn't real cheap but I have no idea how long it lasts or such. So if you run out of the urea fluid does that stop the engine?

Tier-2 (and above) engines have OBD processors that monitor, among many other things, the DEF dispensing directly at the injection point.  Running out of DEF, or a clogged DEF filter, will trigger a "limp-home" mode in the OBD and engine performance will be dramatically reduced until the problem is corrected and the computer reset, to prevent damage to the converter.

You might find this white paper informative if you have a Tier-2 engine:
http://www.spatcodef.com/assets/Uploads/AttachedFiles/Technical/Whitepaper-SuccessfulUreaDieselExhaustFluidHandlingStorageandDispensing.pdf

-Sean
http://OurOdyssey.BlogSpot.com

[belfert]

I was at a Kwip Trip store yesterday and I happened to notice they had 2.5 gallon bottles of DEF for $9.99.  I'm guessing that would not be your first choice of places to buy the stuff if you care about the cost.

I thought I read that some of the large truck stops will be installing DEF pumps alongside the diesel pumps when DEF becomes more popular.

[luvrbus]

Flying J in Phoenix has the piss pumps as the truckers call it I had a time with what they talking about till I asked a driver , truckers you got to love em

good luck

[Busted Knuckle]

Flying J in Phoenix has the piss pumps as the truckers call it I had a time with what they talking about till I asked a driver , trucker you got to love em

good luck

  Hey Clifford I resemble that remark! (or at least I used too!)
  BK 

[Jeremy]

It's called Adblue here:



It's not just for trucks and buses either - some cars (eg Mercedes Bluetec diesels) also need it.


Jeremy