Talk:Diesel exhaust fluid

Less technical
Is there any propsect of a less-technical summary of what this fuel is for? I found this article a bit heavy-going when I was researching fuel options for a general article on motoring. — Preceding unsigned comment added by 83.100.215.10 (talk • contribs) 14:25, 29 May 2007 (UTC)

Non-English links
repeated reinsertion of these Turkish language links from various TurkTelekom IP's: per External_links they appear to add nothing to the article and there are other English language links available -- repeated reinsertion could be considered link spamming. – Zedla (talk) 22:43, 30 January 2008 (UTC)
 * http://www.adbluetr.com
 * http://www.fircasizotoyikama.com/adblue.htm (contains poorly translated English text)
 * Both of these domains are registered to the same person (see and ). – Zedla (talk) 03:36, 31 January 2008 (UTC)

Chemistry, please!
Let's see some! I bet many people visiting this page are at least as interested in science as they are in marketing! —Preceding unsigned comment added by 88.148.218.158 (talk) 06:34, 17 April 2009 (UTC)

Short and Confusing
Going to try and get a less-technical summary, a basic break down of the chemistry, as well as some useful pictures up. There seems to be a bit of trouble explaining it to the extent that it'd be easily understood by someone who isn't familiar with it. Linked an external video with a bit of an explanation as to how it works in the trucks.

JFife (talk) 15:51, 9 July 2012 (UTC)

Edited summary to explain where the ammonia comes from (previously, it was introduced in the summary before any explanation of its relationship with the urea in adblue) Urilarim (talk) 21:36, 3 December 2021 (UTC)

Image/conflict-of-interest issues
Jfife, I have difficulty assuming good faith on your own-work free-image claim on the DEF jug image you inserted. It looks just like the images at the company's website. For now I've reverted to the previous image which has an unquestionable free-image status. Perhaps the images really are yours to distribute as you see fit because you are affiliated with the H2blu company—I notice you're a brand-new user and you've only ever made edits to this article, and the external links you added/I removed go to that same company's website—in which case there are COI issues to be carefully worked out. —Scheinwerfermann T&middot;C 21:34, 9 July 2012 (UTC)


 * Contribution by users with a potential conflict of interest is not forbidden. For any commercial product, someone has to manufacture it, and forbidding photos of products defeats the purpose of images in an article. Adding brand names instead of common nouns or removal of content concerning competing products would be a COI. Adding pictures of a commercial product is not. Likewise, you removed this link, which gives a long general interest introduction to the topic, just not promoting Brenntag. Again, similar reasoning can be used against this. (COI disclaimer: The undersigned is employed by a public university and engaged in research unrelated to the topic of this article.) --vuo (talk) 19:54, 15 August 2012 (UTC)

Bad copy source
The author took material from here: http://h2blu.ca/about-def/how-it-works but it made it look like AdBlue is pourred inside the engine. It is all because of naration style, he modified the source badly. — Preceding unsigned comment added by 195.33.129.54 (talk) 14:43, 20 December 2012 (UTC)

Ammonia as a pollutant
This article is obviously meant to be a joke but is there a serious point behind it? Isn't ammonia just as harmful as nitrogen oxides? Biscuittin (talk) 13:04, 10 September 2014 (UTC)


 * Not really. The problem with nitrogen oxides is that they are surprisingly hydrophobic, so they can get pretty deep inside the lungs. Ammonia, on the other hand, is freely water-soluble. It isn't actually very toxic, since it can be readily eliminated; you can handle even concentrated solutions without much risk. It is harmful to fish, but it would be unlikely for a car to poison a lake just with a slight overstoichiometry of DEF. And the article repeats the common misconception that urine and ammonia are the same thing. Ammonia in DEF is synthetic. Yes, ammonia is an important component of urine. But, so is water an important component of vodka, and you wouldn't call Stolichnaya a brand of mineral water either, would you? --vuo (talk) 21:56, 10 September 2014 (UTC)


 * Only in over-Stolichnometric doses. 89.217.28.204 (talk) 20:29, 11 January 2015 (UTC)
 * Ammonia: "Ammonia is an irritant and irritation increases with concentration; the Permissible Exposure Limit is 25 ppm, and lethal above 500 ppm". cf Wikipedia134.247.251.245 (talk) 10:46, 23 September 2015 (UTC)

Would diesel exhaust fluid be toxic to someone with kidney problems? If a person has a problem eliminating ammonia, would a vehicle with DEF be an additional hazard to the driver? — Preceding unsigned comment added by Naradabill (talk • contribs) 07:49, 18 June 2015 (UTC)

NOx
Just a minor glitch: Although it is common to write NOx when talking about molecules of nitrogen and oxygen, but chemically it's wrong. It assumes that the number of oxygen atoms varies but nitrogen is constant to 1. Which it isn't. There are most commonly NO2 and N2O3, but NO, N2O, N4O, N4O2, N4O6, N2O4 and N2O5 do exist also.

So it would be more correct to write NxOy.134.247.251.245 (talk) 10:41, 23 September 2015 (UTC)
 * No. DEF is only intended to cut down the mono-nitrogen oxides NO and NO2, which are correctly referred to here as NOx. Perhaps we need to add the "mono-" to make it clearer. --Heron (talk) 12:23, 10 February 2016 (UTC)
 * Chemistry is strange sometimes. Often enough, it is written NOx where x can be 5/2 or 3/2. That doesn't quite get some of the ones you list, but often it is close enough. Gah4 (talk) 09:16, 7 December 2022 (UTC)
 * I believe that where an unknown or variable number occurs, as in NO or NO2 where number of nitrogen atoms may be 1 or 2, one should use the n designation. Which would look like NOn. Please, correct me if I am wrong. 24.225.161.193 (talk) 04:55, 4 June 2023 (UTC)
 * Chemistry is strange sometimes. Often enough, it is written NOx where x can be 5/2 or 3/2. That doesn't quite get some of the ones you list, but often it is close enough. Gah4 (talk) 09:16, 7 December 2022 (UTC)
 * I believe that where an unknown or variable number occurs, as in NO or NO2 where number of nitrogen atoms may be 1 or 2, one should use the n designation. Which would look like NOn. Please, correct me if I am wrong. 24.225.161.193 (talk) 04:55, 4 June 2023 (UTC)

Need a section on where it is legally required
I read an article saying that Adblue is required in EU, particularly in Italy. Diesel cars have software counter and won't start when they run out of Adblue even though the engine can perfectly work without it. Which countries require it? Article should have such section. 73.71.174.75 (talk) 06:35, 7 April 2016 (UTC)
 * In Europe, this kind of regulation only exists on european level. Individual countries don't use special rules. Also, there is no legal requirement like "Diesel cars must have an AdBlue system" in Europe. There is a legal requirement to be compliant with emission limits, which nowadays include real driving emission testing both for type approval and for in-service conformity. With todays emission limits, it is considered virtually impossible to get along without using AdBlue. Cars that do need AdBlue to be compliant also need to implement a set of features, such as measuring urea concentration, monitoring AdBlue flow, warn the user if they are soon going to run out of AdBlue, refuse engine start if AdBlue has completely run out, and so on. However, a fictional diesel car that meets todays emission limits without AdBlue can legally be sold and can be used without AdBlue. Rules for AdBlue in passenger cars were introduced with EU-5 regulation in 2008, but for EU-5 and EU-6b most manufacturers decided not to use this option at all, or only in big cars. Alexander Noé (talk) 10:19, 22 July 2022 (UTC)

You are correct, but 5 years later, the situation has changed. The engine management parts of car computers can be programmed to run without Ad Blue. Some more easily that others LOL. Also, there are issues with the DEF injection equipment when they are re-enabled afterwards, but that's for later. — Preceding unsigned comment added by 2001:8003:E422:3C01:2933:7944:F9B2:FA18 (talk) 09:54, 22 December 2021 (UTC)

Chemistry
For NO2, the chemical equation is given as 3NO2 + 4NH3 + 3O2 -> 7/2N2 + 6H2O. However, this isn't balanced in oxygen; it would seem that no oxygen is consumed by the reaction. I've been bold, and fixed this. I've also added overall reactions for generating ammonia gas from urea, and the destruction of NO2 by urea. LongHairedFop (talk) 15:04, 10 April 2016 (UTC)
 * I've added the patent as a source. It agrees with your removal of the oxygen, it's also not clear where all that much free oxygen would have come from. Andy Dingley (talk) 20:50, 10 April 2016 (UTC)
 * Thanks. Can I ask why you removed my addition of     +  → 2 +      for the formation of ammonia from urea? LongHairedFop (talk) 21:16, 10 April 2016 (UTC)
 * Sorry, hadn't noticed that - I've put it back. Andy Dingley (talk) 21:27, 10 April 2016 (UTC)

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When?
I don't see any dates. When did all this happen?Longinus876 (talk) 03:23, 27 January 2018 (UTC)

Percent by what?
The article says that DEF is 32.5% urea. Is that percent by volume, percent by mass, or what? Vaughan Pratt (talk) 21:46, 25 May 2020 (UTC)


 * Percent by mass. Source: https://static.webshopapp.com/shops/021124/files/053436992/msds-adblue-aus-32.pdf Alexander Noé (talk) 16:22, 8 May 2022 (UTC)

Situation in Australia in late 2021
There is a company in Australia that makes Ad Blue. It is called Ensatech. But its plant is shutting down in late 2021 / early 2022 for financial reasons, which as a POV, many Australians find outrageous.

Ensatech uses natural gas as the energy source to make urea. Australia sells natural gas to China for 6c / litre, but domestic users like Ensatech are charged 60c / litre (!!!). The domestic price is going even higher in 2022. In response, Ensatech has said that at the increased price it cannot be cost-competitive with China, and as a result, it is shutting its plant.

The Prime Minister announced in mid December 2021 that he has secured a supply for SOME Ad Blue from Indonesia, but it wont be enough to replace that lost from China and Ensatech. As a result, failing some government action, the Australian trucking industry is expected to run out of Ad Blue completely sometime in mid February.

in Australia, diesel engines on trains do not use this, because the Eu legislation for diesel engines that requires this does not apply to them. — Preceding unsigned comment added by 2001:8003:E422:3C01:2933:7944:F9B2:FA18 (talk) 09:59, 22 December 2021 (UTC)

Over or under stoichiometric?
Look, I havent done any chemistry since 1973, so I ask out of ignorance. This fragment here:

... lean burn air-to-fuel ratio (overstoichiometric ratio) ...

To me, "intuitively", air is free, but fuel has to be paid for, so if you run a lean burn ratio, that is an UNDER stoich (etc) rather than an over.
 * There should be a chemistry convention, but I don't know it, so I assume it is right. A large number of reactions involve something being oxidized, and something else doing the oxidizing. (Not always oxygen.) So someone decides on the convention for it. Gah4 (talk) 17:32, 17 June 2022 (UTC)
 * There should be a chemistry convention, but I don't know it, so I assume it is right. A large number of reactions involve something being oxidized, and something else doing the oxidizing. (Not always oxygen.) So someone decides on the convention for it. Gah4 (talk) 17:32, 17 June 2022 (UTC)

lean is the way diesel engines work
The article mentions lean burn to prevent soot and release unburned fuel. As well as I know, it is fundamental to the way diesel engines work. They compress a fixed, large, amount of air and then inject an appropriate amount of fuel. That fuel then burns, expands, and makes things move. So it is naturally lean at lower power. As you increase the amount of fuel, to increase power (press the pedal) it gets less lean, but presumably stays on the lean side. There would be no advantage to pass it, as there is no more energy to get out. That is different from gasoline engines, which vary the air and gasoline, keeping the ratio more or less constant. Though gasoline engines often run a little on the rich side, to allow the spark to start combustion. The other possibility is with stratified charge, rich near the spark plug, lean away, and on the average about right. Gah4 (talk) 17:39, 17 June 2022 (UTC)

Shortage in Germany
SKW halted production (one of three producers) National New cover it https://www.tagesschau.de/wirtschaft/unternehmen/adblue-mangel-logistikbranche-diesel-abgasreinigung-101.html

--Stone (talk) 14:14, 14 September 2022 (UTC)


 * There has never been a shortage. The alledge shortage, even the alledged danger of a shortage, was made up. SKW tried to get government support, but the government basicly said that they will intervene only if there is an actual shortage. After that was made clear, SKW prepared themselves to continue production, as reported on Sept. 13, 2022. https://www.agrarheute.com/management/agribusiness/duengerhersteller-skw-piesteritz-faehrt-produktionsanlage-597786 Alexander Noé (talk) 09:05, 7 December 2022 (UTC)