DEF... What's the point?

[ianholt150]

What is the point of DEF in new trucks? I know that it cleans the exhaust so it is cleaner when it leaves the truck. If people want to crack down on emissions, look at all of the New Yorkers who fly to Washington D.C. every week. One air mile produces 53.3 pounds of CO2. However, semis only produce 6.472 kg per mile. And if people want their food, water, fuel, cars, phones, garbage hauled away, and their houses built, why do they put emissions restrictions on trucks? If the government wants to restrict something, why don't they say so? I can come up with some restrictions that they could enact rather than affecting the main source of freight movement in the U.S. Why don't they put restrictions on airplanes. They produce 39.0316824 more pounds per mile that trucks.


Whew! Now that I am finished with my rant, I would appreciate any input on this.

 

[Ronsii]

Well.... it created a huge market/profits for something that didn't have one before

 

[check]

look at all of the New Yorkers who fly to Washington D.C. every week. One air mile produces 53.3 pounds of CO2. However, semis only produce 6.472 kg per mile.

Don't try reasoning with bureaucrats. We have to do as they say because it's their policy.

 

[92U 3406]

Because I need OT to fix that junk lol.

 

[Birken Vogt]

It lowers the oxides of nitrogen. Through a process called Selective Catalytic Reduction.

Oxides of nitrogen are produced when fuel burns in a high compression environment.

They are hard to get rid of, once they form. SCR/urea in the presence of a special catalyst reacts with them to convert the NOx back into nitrogen.

In the past they were controlled by EGR. But the bureaucrats set the allowable limits so low that normal technology just would not do it any more so they had to resort to technology thought unthinkable a few years ago. Making people fill tanks with useless fluid. And punishing them with derates and shutdown if they should ever run out or have a malfunction in the system and not repair it within 2 miles and such.

 

[willie59]

It doesn't have anything to do with CO2, as pointed out by Birken Vogt it's to reduce Oxides of Nitrogen, namely Nitric Oxide (NO) and Nitrogen Dioxide (NO2), both are common particulate air pollutants that cause smog and acid rain. Yes, sucks that we have to use this stuff, but I find it works way better than the Diesel Particulate Filter (DPF) systems myself, but that's just my opinion.

 

[td25c]

I'm looking in to a NOS system kit for the 68 Ford Galaxie . Hate the extra cost but it's supposed to burn cleaner & be more environment friendly .
http://www.jegs.com/i/NOS/741/02001/10002/-1

 

[Birken Vogt]

The units that have DEF/SCR generally have DPF installed, also. So you are not rid of that hassle.

I have heard the newer ones are less troublesome than the original DPF only units but I have no experience to back that up.

 

[92U 3406]

Better than EGR too. I hate EGR and its probably the reason for all these premature engine failures. All that nasty soot going straight back into the engine. Yuck!

 

[Birken Vogt]

Don't SCR engines have EGR installed still?

 

[RZucker]

Better than EGR too. I hate EGR and its probably the reason for all these premature engine failures. All that nasty soot going straight back into the engine. Yuck!

EGR and/or Leaky EGR coolers... Not sure which kills an engine faster.

 

[John C.]

Oxides of nitrogen are formed at very high firing temperatures. To reduce firing temperatures they lowered compression pressures and added EGR to lower those temperatures more. That increased fuel usage and put a hit on reliability I think as well. DEF allows higher firing temperatures again which increases efficiency again and raises fuel economy. In equipment I've seen where regens are fewer and having to clean the DPF in the smaller engines is no longer needed. It allows larger engines to use passive regen in some instances.

Still it all is a red herring in that methane is far more the issue with green house gasses than CO2 is. Diary farms and garbage dumps are some of the worst offenders for that gas. Maybe they need to figure out how to add something over a cow's exhaust to clean up those gasses.

 

[Truck Shop]

Better than EGR too. I hate EGR and its probably the reason for all these premature engine failures. All that nasty soot going straight back into the engine. Yuck!

That's correct-the EGR systems would soot out oil real quick oil sampling proves it. With a Def system you can run 30,000 miles fairly safely on oil changes. 15,000 to 20,000
on a straight EGR engine you could cut the oil with scissors as it drained. That's also when the variable pitch turbos came into play and EGR engine disasters like the Detroit
Series 60 DDEC V came along-trying to put 48 to 51 LBS of boost in a engine designed for 30 LBS. You couldn't keep a head gasket in one.

Truck Shop

 

[funwithfuel]

Money, profits, shareholders.
Our emissions with tier 3 reduced PM so much over pump/line/nozzle. The EPA with its overreaching power and legislation by mandate.
I personally carry a grudge with tier IV interim and final.
As mentioned above, derate and shut down for no other reason than your nozzle is plugged, your DEF quality is not pristine or you ran out. Or how bout yer $1800 NoX sensor crapped the bed. No detrimental effects to the engine, no danger posed, the gov't via EPA has mandated that you will repair or suffer to the point of stopping. This is accomplished by software programming. They have decided that you have several operators working, mid-cut, now this guy has to lay his scraper on the side for a forced regen , or to have a tech come out and drain the pee-pee tank refill it and start the whole works all over again. In the meantime your crew all stand around with their thumb up their a$$3$ on the clock costing thousands.
Figure an operator , full package, $125-150 / hr. Now multiply by how many folks on job waiting on the piece of equipment to work as intended.
Some mom n pops dont have the finances to recover from a chronic/ intermittent problem that the "factory/dealer mechanic" can't figure out.
But hey , its ok. DEF is totally safe. Right. It corrodes everything it touches. Containers cannot be made non poisonous. Oh, and you can only handle it with plastic or a specific grade of stainless. So, all these plastic jugs and drums gotta go somewhere, right? But its ok. Nothing but sunshine and butterflies coming out your tailpipe.
Oh yeah tier IV is sooo good.
And a little more, if your tier IV compliant machine sells at auction to a third world or "developing" country, get this. At the port, the local dealer tech will come and delete everything for them, unrestricted/unsilenced air filtration. Unrestricted exhaust. They get a real gain of between 50 and 200 hp depending on machine and engine size. Why do we get penalized for being a developed country.

Now i will quietly step down from the soapbox.

 

[Truck Shop]

Maybe they need to figure out how to add something over a cow's exhaust to clean up those gasses.

It's been around for awhile it's called a BIC lighter.

Truck Shop

 

[willie59]

The units that have DEF/SCR generally have DPF installed, also. So you are not rid of that hassle.

I have heard the newer ones are less troublesome than the original DPF only units but I have no experience to back that up.

Just to clarify, which I didn't do a good job of, my gripe with the straight DPF systems is their need for re-gen, it's a PITA. And even with proper re-gen sooner or later you have to remove the DPF filter and have it cleaned out (money), and the catalyst eventually burns up (money), not to mention, to re-gen, hmm, I got an idea, let's dump diesel into the catalyst/DPF filter system to burn up those nasty nasties that are produced by diesel combustion. Brilliant...burn more of my fuel! Just seems to me the newer DEF systems don't have to deal with the BS of the straight DPF systems do even though they add a new layer of problems.

 

[Truck Shop]

In the fertilizer industry DEF fluid is basically solution 32. Farmers have been using it on crops for years.

Truck Shop

 

[Truck Shop]

Just to clarify, which I didn't do a good job of, my gripe with the straight DPF systems is their need for re-gen, it's a PITA. And even with proper re-gen sooner or later you have to remove the DPF filter and have it cleaned out (money), and the catalyst eventually burns up (money), not to mention, to re-gen, hmm, I got an idea, let's dump diesel into the catalyst/DPF filter system to burn up those nasty nasties that are produced by diesel combustion. Brilliant...burn more of my fuel! Just seems to me the newer DEF systems don't have to deal with the BS of the straight DPF systems do even though they add a new layer of problems.

Any truck with def system will need repairs to the system before 300,000 miles you can't get away from it. Just a mere 3 grand.

Truck Shop

 

[DARO]

DEF stands for
Da
Education
Fund
If you fix for a living

 

[funwithfuel]

My first experience with tier IVi was with an 11 liter engine. During pre delivery, perform a service regen. Now , i had filled the fuel tank as was practice. Started the unit, got it up to temp and initiated a regen. This process took almost an hour. In that time no function could be activated, as that would cancel the regen. An hour later, the machine had consumed 11.5 gallonsof fuel without doing a lick of work.
Remember when we were supposed to be saving fuel, tightening up on consumption.