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(Post Link) post #1 of 79 Old 24-07-15 Thread Starter
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Pilot injection

Hello

Can someone confirm that on our cars, pilot is turned off as soon as engine temp hits 73,26 C or is something wrong? It make sense but just what confirmation.

Thanks
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Quote:
Originally Posted by Xinoka View Post
Hello

Can someone confirm that on our cars, pilot is turned off as soon as engine temp hits 73,26 C or is something wrong? It make sense but just what confirmation.

Thanks
??????
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(Post Link) post #3 of 79 Old 24-07-15 Thread Starter
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What did you don't understan? Pilot injection drops to zero at that temp.
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I think my 1.9 swiched off at 60c
did some logging right up to temp to see what was changing and when it changed
heres what I had post 172 (don't know if your 2.4 will be different)
mines a cf4 jtdm 1.9 16v
https://www.alfaowner.com/Forum/tunin...jtd-16v-7.html
pilot injection stopped at 60c
some injection timing changes were at 70c
and again at around 73c timing changes, main quantity drops a tad
https://www.alfaowner.com/Forum/attac...8&d=1395162012
https://www.alfaowner.com/Forum/attac...2&d=1395162500
https://www.alfaowner.com/Forum/attac...6&d=1395162036

only way to know for sure what yours is doing is to log a full warm up cycle.

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Pilot injection should be on all the time, it keeps noise and emissions down.
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there's 2 pilot injections though...
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Safer to call them as mes lists them
Pilot injection
Pre injection
Main injection

I asked something similar a while ago as i wanted to play with pilot and pre injections to try to quieten the engine noise down a tad, there was no real info or tuners reply who actually tried playing with these.
I left as was.
So those graphs i posted higher up were stock (maybe egr disabled, which may alter something or not, and main inj soi changed I think at this time(advanced from oe ))

Does your 2.0jtdm do more injection events ? I beleive the newer piezzo injectors could do many more pilot / pre injections due to faster operation for a more shapable combustion event.

Last edited by sussexa; 27-07-15 at 10:47.
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(Post Link) post #8 of 79 Old 27-07-15 Thread Starter
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Did full warm up cycle while driving, so it's difficult to compare with yours. Will do another at idle. Since mine is cf4, it must be almoust identical. Nutron, that's the theory but there must be some strategy behind this behaviour and EGR is my main suspect.
On hexdump, pilot and pre are PiI1 and PiI2 imo.
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Originally Posted by sussexa View Post
Safer to call them as mes lists them
Pilot injection
Pre injection
Main injection

I asked something similar a while ago as i wanted to play with pilot and pre injections to try to quieten the engine noise down a tad, there was no real info or tuners reply who actually tried playing with these.
I left as was.
So those graphs i posted higher up were stock (maybe egr disabled, which may alter something or not, and main inj soi changed I think at this time(advanced from oe ))

Does your 2.0jtdm do more injection events ? I beleive the newer piezzo injectors could do many more pilot / pre injections due to faster operation for a more shapable combustion event.
jtdm-2 can inject 7 times per cycle, I believe... but they're not using piezo injectors.

more common however is 5 injections per cycle, 2 pre, 1 main and 2 post (the last one for regens)
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Well I increased the values for pre-injection on mine for higher IQs as that should give better performance too. I did try turning them off once and it sounded like a somebody was smashing pans together under my bonnet.
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(Post Link) post #11 of 79 Old 27-07-15 Thread Starter
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In your cdti it's always on?
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The map has standard injection values for the whole rpm range and right upto max fueling
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Well I increased the values for pre-injection on mine for higher IQs as that should give better performance too. I did try turning them off once and it sounded like a somebody was smashing pans together under my bonnet.
pilot injection hurts power and economy, especially pilot 2 (the very first ignition event). I believe this is the pilot injection that gets turned down and off when the engine heats up.
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Why do you think it hinders power?
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(Post Link) post #15 of 79 Old 29-07-15 Thread Starter
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Did you cheeked that pilot is always on or it's just based on map configuration?
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(Post Link) post #16 of 79 Old 29-07-15 Thread Starter
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Already found the maps and its correct pilot turned off at 73C

sussexa, you could try and change axis to this temp. Mine is using factor 1 at 72C but you can leave it at std 0,5 to begin with.

This engine is smooth and quiet only when it is pushed hard. Since IAT is the only parameter than influences pilot at this conditions, will try to mess with it to increase pre combustion temp at lower IAT. What do you think?
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im sure fitting of fmic and other mods to keep iat cool have made the engine more harsh(at idle), and for sure theres an audable change on mine when that first cut off of pilot injection plus total fuel quantity goes up a fair bit so yeh wouldn't be against tinkering with pilot in parallel tests to you.
ive not got the best map finding ability, so quicker for you to pm me or post up map addresses etc, as will take me far too long to find with my free winols.
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(Post Link) post #18 of 79 Old 29-07-15 Thread Starter
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yes, in theory, fmic doesn't help in terms of engine noise but i think that the main culprit is the low maf, replaced by active egr.
Have to log all output values of egr at that temp to see if there is any major change.
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Why do you think it hinders power?
pilot injection happens early in the compression stroke, and has finished burning before the end of compression. The intent is to get the air warmer by the end of the compression stroke, and the start of the 2nd and main injection.

Downside isthat there's negative work being done on the piston, so I'd keep the pilot injection as low as tolerable...
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It is a small quantity though and ensures instant ignition of the main phase.
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You could adjust the max SOI for pilot injection, that is 49 deg on the fiat map I have but only 45 on my standard map.

There are correction maps for Engine temp, atmospheric pressure and intake air temp and quantity maps for the first two.

I have found a PiInj 1 & 2 shut off for engine temp but there are PiInj 1, PiInj 2 and PiInj 3 as well as the post injection for regeneration.

No, found all three, and they seem to be shut off for around 70 deg on my engine too
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(Post Link) post #22 of 79 Old 29-07-15 Thread Starter
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Do you know what Pilot 3 stands for? Havent figure it out but there is one map that replaces Pilot 2 when inactive.

About Pilot doing negative mechanical work, its unlikely that 1 to 1,5mm3 of injection can have enough energy for that and thats why its done in two phases.
On EDC16C31 there is this map:
"InjCrv_tiPiI1Bas1FDC_MAP: base map of PiI1 SOE time calculation, if PiI2 is inactive for sport mode 16x16"
Can it be shut down just to reduce injector Duty Cycle or low Pulse-Width for stability purposes?
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I have an EDC16C39 and there are dozerns of maps for compensation, some of the PI 1 maps refer to compensation when PI 2 and 3 are running only.

I've shut off PI3 completely and reduced PI2 to only come on below 2000rpm. It starts and runs fine still with no extra noise. I could cut out PI 1 by adjusting the temp compensation to 0 for all temps and that would only leave PI 2 active.
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(Post Link) post #24 of 79 Old 30-07-15 Thread Starter
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PiI1 pre, PiI2 pilot, PiI3 ???
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I don't know but you have post injection too if you have a DPF
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