DEF, Regen questions

[RustyJC]

The engines you studied and researched were compression ignition engines. So by default the pressure was more than 1 atm at the "top" of their compeessions stroke. If you created NOx with just a flame (no compression or pressure) and you published your research, i would be interested in reading that

Otto-cycle engines are not compression ignition engines - they are typically spark-ignited (even using a precombustion chamber). Diesel engines are compression ignition engines. Both compress the charge (or air, in the case of the Diesel-cycle engine) before combustion occurs - I don't recall ever saying they didn't. However, it's the combustion process that produces NOx, not the compression stroke.

Rusty

 

[Newsa]

. Both compress the charge before combustion occurs - I don't recall ever saying they didn't.

Then this morning, I misunderstood you when you said that NOx formation is ONLY time and temperature dependent.

 

[RustyJC]

Then this morning, I misunderstood you when you said that NOx formation is ONLY time and temperature dependent.

It is. NOx is produced at the burner tip of coal, oil and natural gas fueled boilers where the flame box operates at basically atmospheric pressure. No compression is involved - any fans are there for flow, not compression.

Rusty

 

[Newsa]

Please find proof of this and post here. THX

 

[RustyJC]

Please find proof of this and post here. THX

OK, here ya go. If you want to Google "NOx production by boilers", there's lots of material for your review.

http://www.boilerenergyefficiency.com/forms/Boiler_NOx_and_Energy_Efficiency_2010.pdf

Rusty

 

[Newsa]

Ok thanks. I guess if the flame goes 24 hours per day, there is enough NOx produced to be noticable. I learned something here

 

[Newsa]

But that's pretty slick to say my gas turbine engine abstract was a useless example of how NOx increases with pressure. And your example of a boiler is not even an engine. I do stand by my original statement that NOx production increases significantly with higher pressure.

Edit: (because it is too difficult to compare combustion-ignition with spark ignition engines)

If you run a gas turbine engine like this http://www.sciencedirect.com/science/article/pii/S0010218007001137
at higher pressure for a short amount if time...... you can produce the same NOx emissions running the same engine with the same fuel at the same temperature at a lower pressure for a longer amount of time.

That is the Time/Temperature/Pressure point I was trying to make.

 

[Kirwin]

Thanks for the schooling Rusty. I had assumed that the Nitrogen and Oxygen both came from the combustion air not the fuel hydrocarbons breaking apart during combustion. Fuel being made up of hydrogen, oxygen and carbon molecules, it makes sense now. Interesting reading here. Ken Irwin

 

[RClark]

I have only 6100 miles on the truck, about 1/3d towing. Haven't noticed any refer although the DEF is used. What are the indications of the region with the DEF system?

 

[kthaxton]

Haven't noticed any refer although the DEF is used. What are the indications of the region with the DEF system?

I'm not understanding either sentence? What do you mean?

 

[RClark]

For refer substitute regen. The safe for region.

 

[kthaxton]

As mentioned by various people in this thread, there are a few clues that a regen is taking place. I haven't even noticed one in more than a year.

DEF gets used all the time, it has nothing to do with regens.

 

[Jaycam2004]

The Smell. What does it smell like? Is it simular to the smell of hot brakes?