Yeah, and don’t put urine in it either…
gbtransp:
norb:
For the EAS (Exhaust Aftertreatment System) to operate certain criteria /parameters have to be met…ie on the manufacturers trucks i have been working on for 17 years(a) exhaust system temp before and after the cat has to be above 200 degrees C
(B) there has to be a load on the engine ie producing torque ,as that is when NOX is at it’s greatest
(c) ad blue is injected up stream of the cat ,before the ad-blue gets to the cat,the ad blue breaks down in to ammonia and carbon dioxide…The vanadium in the cat attracts amonia…The NOX CONSISTS OF 90% nitrogen momoxide and 10% nitrogen dioxide.the gases that flow through the cat come in to contact with the amonia,and the resulting reaction converts nitrogen oxides in to nitrogen and water(d) if a vehicle is on over run or sat idling no ad blue will be injected…as the temps will drop below 200,and the amount of NOX is minimal…
(e) that is why vehicles doing town driving will use less that a vehicle on motorway work
(f) running out of ad blue is a 1drive cycle fault hence the warnings on the dash and there will be a error logged in the ECU saying out of ad blue or words to that effect…since the ECU knows that it is out of ad blue ,when you refill the tank it will extinguish the warning ,though the fault will still be stored in the ECU
(g) if you want to know what drive cycles are just ask
(h)if you are under the impression that ad blue is injected as soon as you turn on the engine ,your dilussional ,as you would run out of ad blue pretty quicklylooking forward to you intelligent reply…
this post was not aimed at the op but at BKING who reckoned my first reply was " bollox" but has since deleted his post
Intresting stuff , i knew the half of it ;now i know the rest,
except!!! i believe add blue starts to freeze at below -10c what tells the system that its frozen and has not run out of add blue ?
Geoff
I’m pretty sure the tractor I drive has an adblue heater so by the time it’s needed it won’t be frozen, you would’ve thought trucks are the same.
Read through Norb’s post on how the system works, but one aspect puzzles me. Many vehicles act like an old Gardner when cold and chuck out clouds of smoke (I assume it is actually be water vapour) for the first half mile out of the yard from a cold start. I have always assumed that this was as a result of adblue being injected. However from Norb’s explanation it would appear that the exhaust gas temperature needs to be above a certain level for adblue to be injected. With a cold engine the situation is the exact opposite; the exhaust gas temperature is low due to the low cylinder temperature, which in turn means that there is incomplete combustion and hence clouds of smoke out of the exhaust.
The emissions from the adblue equipped vehicle when cold are not of the same choking nature as from vehicles of an earlier generation, however vehicles which use an EGR system rather than adblue do not seem to emit anything when cold.
stevieboy what you may find with you vehicle is that the ad blue tank is not near the exhaust …with DAF for example you will find the adblue tank beside the exhaust and the heat of the exhaust keeps the tank warm ,so they told me lol…on the vehicle such as 4 axle jobs the ad blue tank is on the opposite side of the vehicle and like your vehicle there is a metal coolant pipe in the ad blue tank circulating warm coolant…
In winter months if the ambient /outside air temp is too low then there will be no ad blue usage what so ever .Even we can’t carry out tests on a vehicle with a fault as the DAVIE won’t let us…On CF XF DAFS for example /except CF65 .if the ambient temp sensor if faulty you will get a warning on the dash .as the engine uses it
cav551:
Read through Norb’s post on how the system works, but one aspect puzzles me. Many vehicles act like an old Gardner when cold and chuck out clouds of smoke (I assume it is actually be water vapour) for the first half mile out of the yard from a cold start. I have always assumed that this was as a result of adblue being injected. However from Norb’s explanation it would appear that the exhaust gas temperature needs to be above a certain level for adblue to be injected. With a cold engine the situation is the exact opposite; the exhaust gas temperature is low due to the low cylinder temperature, which in turn means that there is incomplete combustion and hence clouds of smoke out of the exhaust.The emissions from the adblue equipped vehicle when cold are not of the same choking nature as from vehicles of an earlier generation, however vehicles which use an EGR system rather than adblue do not seem to emit anything when cold.
cav551 correct as i notice first thing in the morning that scr motors are smokey first thing ,but its not the choking blue ,oil or black ,fuel .and as soon as there is a bit of temp build up it disappears…too be honest i’ve never thought too much about it and can only imagine it is vapour ,but i will try and find out exactly what it is ,like you say it disappears pretty quickly and it’s not irritating
cav551:
Read through Norb’s post on how the system works, but one aspect puzzles me. Many vehicles act like an old Gardner when cold and chuck out clouds of smoke (I assume it is actually be water vapour) for the first half mile out of the yard from a cold start. I have always assumed that this was as a result of adblue being injected. However from Norb’s explanation it would appear that the exhaust gas temperature needs to be above a certain level for adblue to be injected. With a cold engine the situation is the exact opposite; the exhaust gas temperature is low due to the low cylinder temperature, which in turn means that there is incomplete combustion and hence clouds of smoke out of the exhaust.The emissions from the adblue equipped vehicle when cold are not of the same choking nature as from vehicles of an earlier generation, however vehicles which use an EGR system rather than adblue do not seem to emit anything when cold.
The clouds of (white) “smoke” you see for a while after a cold start are indeed largely water. Water is produced in significant quantities when you burn any hydrocarbon fuel (water molecules being made by combining hydrogen and oxygen - the other major combustion by-products being carbon monoxide, carbon dioxide and nitrous oxide). As the warm gases emerge from the exhaust tailpipe, they meet the cold outside air and the (invisible) water vapour they contain immediately condenses out into (visible) water droplets - fog, in other words. Once the exhaust system has heated up to normal operating temperature, the gases that emerge from the tailpipe are much hotter, and so the water does not immediately condense out to form a visible fog - instead the hot gases mix with the surrounding air, which is able to absorb most of the moisture.
Incomplete combustion results in grey/black smoke, because of the carbon (soot) content, and will be visible regardless of exhaust system temperature. White “smoke” (actually fog) disappears as the moisture is eventually absorbed by the ambient air, whereas grey/black smoke does not disappear - in still air it will hang around until the soot particles fall to the ground, but in a moving airstream it is mixed with the air until it is not thick enough to be visible.
Most Ad blue systems have what is known as non - injectable volume so even when the gauge reads empty there is enough ad- blue left in the system to be pumped round and cool the ad- blue injector but will not be injected into the system so in theory it never truly runs right out.
Steve
norb:
For the EAS (Exhaust Aftertreatment System) to operate certain criteria /parameters have to be met…ie on the manufacturers trucks i have been working on for 17 years(a) exhaust system temp before and after the cat has to be above 200 degrees C
(B) there has to be a load on the engine ie producing torque ,as that is when NOX is at it’s greatest
(c) ad blue is injected up stream of the cat ,before the ad-blue gets to the cat,the ad blue breaks down in to ammonia and carbon dioxide…The vanadium in the cat attracts amonia…The NOX CONSISTS OF 90% nitrogen momoxide and 10% nitrogen dioxide.the gases that flow through the cat come in to contact with the amonia,and the resulting reaction converts nitrogen oxides in to nitrogen and water(d) if a vehicle is on over run or sat idling no ad blue will be injected…as the temps will drop below 200,and the amount of NOX is minimal…
(e) that is why vehicles doing town driving will use less that a vehicle on motorway work
(f) running out of ad blue is a 1drive cycle fault hence the warnings on the dash and there will be a error logged in the ECU saying out of ad blue or words to that effect…since the ECU knows that it is out of ad blue ,when you refill the tank it will extinguish the warning ,though the fault will still be stored in the ECU
(g) if you want to know what drive cycles are just ask
(h)if you are under the impression that ad blue is injected as soon as you turn on the engine ,your dilussional ,as you would run out of ad blue pretty quicklylooking forward to you intelligent reply…
this post was not aimed at the op but at BKING who reckoned my first reply was " bollox" but has since deleted his post
For those trucks in a town driving duty cicle or/and too many hours idling.
- The continuos operation in such condition wil not reduce the SRC (catalist) life?
The question is because the low temperature also resul in raw fuel in the exhaust system,it
may contamine the SCR.
Edzio,
there won,t be any raw fuel in the fuel in the exhaust ,all ad blue is basically doing is helping in reducing he amount of NOX in the exhaust gases before they exit in to the atmosphere …technically a cat is being poisoned as soon as you turn the ignition key ,it is like most items it will wear out and it’s efficiency is reduced the older it gets
Roymondo:
cav551:
Read through Norb’s post on how the system works, but one aspect puzzles me. Many vehicles act like an old Gardner when cold and chuck out clouds of smoke (I assume it is actually be water vapour) for the first half mile out of the yard from a cold start. I have always assumed that this was as a result of adblue being injected. However from Norb’s explanation it would appear that the exhaust gas temperature needs to be above a certain level for adblue to be injected. With a cold engine the situation is the exact opposite; the exhaust gas temperature is low due to the low cylinder temperature, which in turn means that there is incomplete combustion and hence clouds of smoke out of the exhaust.The emissions from the adblue equipped vehicle when cold are not of the same choking nature as from vehicles of an earlier generation, however vehicles which use an EGR system rather than adblue do not seem to emit anything when cold.
The clouds of (white) “smoke” you see for a while after a cold start are indeed largely water. Water is produced in significant quantities when you burn any hydrocarbon fuel (water molecules being made by combining hydrogen and oxygen - the other major combustion by-products being carbon monoxide, carbon dioxide and nitrous oxide). As the warm gases emerge from the exhaust tailpipe, they meet the cold outside air and the (invisible) water vapour they contain immediately condenses out into (visible) water droplets - fog, in other words. Once the exhaust system has heated up to normal operating temperature, the gases that emerge from the tailpipe are much hotter, and so the water does not immediately condense out to form a visible fog - instead the hot gases mix with the surrounding air, which is able to absorb most of the moisture.
Incomplete combustion results in grey/black smoke, because of the carbon (soot) content, and will be visible regardless of exhaust system temperature. White “smoke” (actually fog) disappears as the moisture is eventually absorbed by the ambient air, whereas grey/black smoke does not disappear - in still air it will hang around until the soot particles fall to the ground, but in a moving airstream it is mixed with the air until it is not thick enough to be visible.
Guess this water vapour is a result of exhaust gases forced againt the catalist “ceramic”.
They have about 300 mm of lenght and small diameter.
In the morning they are cold - and so cool the exhaust gases.
norb:
Kerbdog:
Just stick some water in itAs said earlier don’t put water in it …AD BLUE is 32.5% urea and 67.5 % water as it is …Any more water can damage the system,as ad blue should be made using distilled water …If you use tap water ,depending on where you live ,then the lime will trash it,also the ad blue will be weaker ,the NOX sensors won’t see a suffient reduction in NOX as there isn’t enough UREA in the system ,and the system will just keep pumping in the water to try and clean it up,which it wont,so you will end up with a warning ,as the NOX reading are too high
Iknow with the early euro 4 motors that never had NOX sensors that people put all sorts in the tank as even with a fault they didn’t derate …The derate came with euro 5 as thats when the NOX sensors where added
I was just interested which trucks did not have these NOX sensors? does anyone know for definite which didn’t use them? correct me if im wrong but doesn’t that make the adblue system useless as you can put any liquid you like in it?
norb:
there won,t be any raw fuel in the fuel in the exhaust ,all ad blue is basically doing is helping in reducing he amount of NOX in the exhaust gases before they exit in to the atmosphere …technically a cat is being poisoned as soon as you turn the ignition key ,it is like most items it will wear out and it’s efficiency is reduced the older it gets
What I was trying to say is fuel unburned comming to exhaust system.
In cold a day,if you leave the engine idling for some time and take a look in the exhaust manifolds
you will find there is raw fuel comming from combustion chambers.
This becase diesel engines have low thermal efficiene at idle.
Going back to SCR - do small drops of fuel kill the catalist over the time?
norb:
Dennisthemenace:
norb:
When you run out of ad-blue the vehicle will derate ,but will return to normal when you refill…
how long your ad-blue lasts ,haven’t a clue as motorway work uses more ad blue than city centre work for example ,a vehicle will only use ad blue when the parameters are met and when the engine is under load ie loaded going up a hill and foot flat to the floor,it doesn’t use ad-blue as soon as the engine starts as some believeNot necessarily; I had to take a Stralis to Ireland a half a year ago and somebody let the adblue level going down too low. After they filled up again, the comp did not reself itself, so I had a serious lack of power for all over the week. After I come back they had to take her to an Iveco dealer to reset it.
Thanks dennisthemenace for your reply to my earlier post ,personally i work on DAF and go on how their system works when they run out of ad blue …At least you just didn’t put bollox to what i had written
How is made the confirmation of a DAF clogged SCR (catalyst)?
You must cut a window in the cover like in the IVECO ones?
Edzio,