Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: STEMO on 11 January 2016, 15:24:48
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Not sure if this is correct, but I choose to believe it is :)
On previous generation Nissan 1.5 dci engines, there was a DPF light - this would illuminate if the engine management system determined that the DPF could be blocking up by sensing exhaust back pressure and the history of your driving style (worst case is slow speed, stop-start). The light would come on telling you to drive the car a 'high' speed for a sustained period to increase the exhaust gas temperature and burn off the soot...
On the Euro 5 version (fittedin your Captur if you have a diesel of course..), there is no DPF light. The engine management system has OCS (oil condition sensing).. this system determines if it believes the DPF may be at risk of being blocked in much the same way, but to regenerate, it does not require you to drive at higher speed for a sustained period. Instead, it uses 2 strategies..
1. Post-injection of fuel - after the main combustion event (the one that creates your power..) there is a small additional injection of fuel that burns into the exhaust, increasing the gas temperature, burning off the soot..
2. The engine is fitted with a 5th fuel injector in the exhaust that pumps fuel into the DPF to raise the temperature and burn off the soot
Both are done regardless of engine/driving speed and are invisible to the driver.
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Other news: "tractor incorporates bodge to make it pass emissions tests".
;)
But yes, what you describe sounds like a DPF regen cycle as is commonplace. I think you still need to keep driving it at a reasonable speed during the cycle as it will fail if the engine is not under reasonable load, then keep trying again... Not easy if there's not a light on the dash, of course.
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The 1.5 was woeful on regens and hence the light, caused huge issues.
All they have done is add bits to try to improve it but, it still regens and still needs to regen for a period of time under load :y
To put it into perspective, item 1) is the standard method for increasing exhaust temperatures to get the DPF to the circa 500-600 degC needed to burn off the soot, on the 1.5 this was always a bit of an issue so they added an additional 5th injector which does the same......all be it direct into the exhaust.
Does your derivative how the catalytic NOX control system or the tank of piss?
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Other news: "tractor incorporates bodge to make it pass emissions tests".
;)
But yes, what you describe sounds like a DPF regen cycle as is commonplace. I think you still need to keep driving it at a reasonable speed during the cycle as it will fail if the engine is not under reasonable load, then keep trying again... Not easy if there's not a light on the dash, of course.
I seem to recall the light was a 'your on your third chance don't f it up this time'
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Other news: "tractor incorporates bodge to make it pass emissions tests".
;)
But yes, what you describe sounds like a DPF regen cycle as is commonplace. I think you still need to keep driving it at a reasonable speed during the cycle as it will fail if the engine is not under reasonable load, then keep trying again... Not easy if there's not a light on the dash, of course.
I am willing to bow to anyone who superior knowledge on this, Kevin, it would just be nice if it was true. :)
Someone will piss on my parade soon, no doubt.
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Other news: "tractor incorporates bodge to make it pass emissions tests".
;)
But yes, what you describe sounds like a DPF regen cycle as is commonplace. I think you still need to keep driving it at a reasonable speed during the cycle as it will fail if the engine is not under reasonable load, then keep trying again... Not easy if there's not a light on the dash, of course.
I seem to recall the light was a 'your on your third chance don't f it up this time'
Ahhh....the man. Spill your guts, Mark. ;D
Edit....ooops...you already have. :-[
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The 1.5 was woeful on regens and hence the light, caused huge issues.
All they have done is add bits to try to improve it but, it still regens and still needs to regen for a period of time under load :y
To put it into perspective, item 1) is the standard method for increasing exhaust temperatures to get the DPF to the circa 500-600 degC needed to burn off the soot, on the 1.5 this was always a bit of an issue so they added an additional 5th injector which does the same......all be it direct into the exhaust.
Does your derivative how the catalytic NOX control system or the tank of piss?
Catalytic NOX.............I am guessing due to there being no tank of piss.
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That's a bonus and as it should be on a small engine and small light car (e.g. as per the competition!)
So just to confirm, the 5th injector does but one thing, allows the revs to a be a bit lower during regen as the fuel dumped in the exhaust by it can't get into the oil via bore wash (which was the key limiting factor to a regen using late injection at low revs).
What none of it does is remove the need to drive under load for a period of time to allow the regen to occur.
And yes, the old DPF did not light during a regen, it lit as a warning of 'your last chance'
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Why are modern derv drinkers affected this way when older generation derv are not?
Seems a backward step to me.
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Why are modern derv drinkers affected this way when older generation derv are not?
Seems a backward step to me.
Its all about emissions me good Lord Opti.
Un clever people in positions of power legislate that horrible particulates and NOx can't come out the back so there is a need to address it somehow, the manufacturers then use the tools in the cupboard to meet the legislation.....the result is tanks of piss and filters (and/or fudge the results!) or the option to abandon diesel engines (as some of the Japs did e.g. Nissan who buy their donks from the frogs....actually not a great move for them as they can be a bit problematic)
Of course older cars which were not subject to said legislation don't need to meet this
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That's a bonus and as it should be on a small engine and small light car (e.g. as per the competition!)
So just to confirm, the 5th injector does but one thing, allows the revs to a be a bit lower during regen as the fuel dumped in the exhaust by it can't get into the oil via bore wash (which was the key limiting factor to a regen using late injection at low revs).
What none of it does is remove the need to drive under load for a period of time to allow the regen to occur.
And yes, the old DPF did not light during a regen, it lit as a warning of 'your last chance'
Thanks, Mark. I usually take my Astra to Liverpool on visits but, if I have the room to accommodate the dog crate in the Renault, I'll take that to give it a run.
50mph for most of the journey actually. Fickin M62. :(
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Why are modern derv drinkers affected this way when older generation derv are not?
Seems a backward step to me.
Its all about emissions me good Lord Opti.
Of course older cars which were not subject to said legislation ......
I wonder how much NOx and particulates are emitted when running an old TD on veggie oil compared to Derv? :-\ ::) ;D
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Why are modern derv drinkers affected this way when older generation derv are not?
Seems a backward step to me.
Its all about emissions me good Lord Opti.
Of course older cars which were not subject to said legislation ......
I wonder how much NOx and particulates are emitted when running an old TD on veggie oil compared to Derv? :-\ ::) ;D
Surely............when the filter is super-heated, all the shit that has built up is released anyway. :-\
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I am terrably sorry officer for speeding but my vehicle handbook told me i had to run at high revs to clean my DPF filter ;D :D :y
Keith ABS
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Surely............when the filter is super-heated, all the shit that has built up is released anyway. :-\
That's the short and long of it! But, when it comes to MOT time, it'll be squeaky clean!
'They' must think 'we' are stupid.
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Why are modern derv drinkers affected this way when older generation derv are not?
Seems a backward step to me.
Its all about emissions me good Lord Opti.
Of course older cars which were not subject to said legislation ......
I wonder how much NOx and particulates are emitted when running an old TD on veggie oil compared to Derv? :-\ ::) ;D
Surely............when the filter is super-heated, all the shit that has built up is released anyway. :-\
Nope, so the DPF traps the particulates (which are mainly un-burnt 'bits'), when the regen starts the DPF gets heated to close on 600 degC at which point trapped stuff burns resulting in mainly ash (and not all of this leaves via the exhaust hence why DPFs have a finite life).
On the NOx side, a reaction takes place in the catalyst (or the Urea on the 'Blue' setups) which reduces it to a less harmful product.