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 Post subject: king new software
PostPosted: Thu Apr 19, 2018 2:33 pm 
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Joined: Thu Apr 11, 2013 9:39 am
Posts: 67
Does anybody know what does the split fuel do in the new software?
there is a bar filled with gas pressures from 1.1 to 1.8 bar, each one associated to a %
if I fill the 1.1 bar pressure with 5%, does it means the system will add 5% petrol?
and what is the "injector heating" option?
any ideas?


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 Post subject: Re: king new software
PostPosted: Thu Apr 19, 2018 4:04 pm 
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Joined: Mon Jan 23, 2012 12:21 pm
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Location: Milton Keynes
The injector heating option will pulse the gas injectors to warm them up before switching over.

Your other assumption sounds right to me, but can't confirm it for sure.


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 Post subject: Re: king new software
PostPosted: Sun Apr 22, 2018 9:41 am 
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Thanks Brian
unfortunately I couldn't find any guide for this...


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 Post subject: Re: king new software
PostPosted: Sun Apr 22, 2018 9:01 pm 
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Joined: Mon Jan 23, 2012 12:21 pm
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Location: Milton Keynes
Looking at the wording in the software (what there is of it) then it does allow split fuel by setting a percentage of petrol to be added calculated from the gas pressure as you suggest.

Depending what your trying to do its also possible to add petrol via the box above, based on the injector timing and rpm threshold set there.

You shouldn't need the heating option under most circumstances (As far as i know its only there to help worn/sticky injectors that may play up when cold). Petrol addition depends what your trying to fix for anyone to advise you.


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 Post subject: Re: king new software
PostPosted: Mon Apr 23, 2018 5:14 am 
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Thanks Brian
I'm just playing with the new software not really trying to change anything. Was curious about these new options


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 Post subject: Re: king new software
PostPosted: Sat May 12, 2018 9:41 am 
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Joined: Wed Sep 29, 2010 5:01 pm
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Location: Yorkshire
From memory...

The split fuelling works much as you're thinking, except that the gas pressure row is absolute gas pressure not delta pressure (not gas pressure minus manifold pressure).

You could set it to have a similar effect to the petrol addition facility but with a rising proportion of petrol addition as manifold pressure increases (because delta pressure being manifold pressure referenced means gas pressure increases as manifold pressure increases). Might beg the question why split fuelling doesn't have a manifold pressure row instead of gas pressure... better to have gas pressure row because if you set say 40% petrol at 0.8bar manifold pressure (high engine load for normally aspirated) with 50% addition at 0.9 bar, then if the reducer pressure starts to fall due to running out of gas the petrol proportion of fuelling would decrease so the reducer (gas) would have to make up more proportion of the fuelling causing a cascade effect that causes the system to quickly switch back to petrol before gas injectors got to 100% duty cycle.

Also since split fuelling is gas pressure not manifold pressure referenced you could set the split fuelling with falling addition as gas pressure rises (which is the same as rising proportions of petrol addition as gas pressure falls, which is the opposite to the curve of percentage petrol addition in the paragraph above) to prevent running out of gas injector dc window and/or switching back to petrol due to falling gas pressure but would have to be careful with settings not to have a situation where the system didn't switch back to petrol when it should (when gas pressure falls off due to running out of gas lol), e.g. could end up with a situation where settings cause it to idle on 90% petrol when really it ought to have switched back to petrol fully.

The split fuelling facility was around for ages in (I think) Lovato software, software which has very similar controls to AEB stuff because AEB makes Lovato ECUs.. Seems to me that AEB just added a similar (not identical) facility to the Lovato facility to other ECUs. By default Lovato adds some petrol addition when gas injector dc approaches 100% (where other AEB systems typically momentarily switch back to petrol while the near 100% dc situation would exist and flash the gas status light on the switch while this is happening or switch back to petrol fully if gas pressure falls below around 50% working pressure / user defined minimum pressure on later ECUs).

Been a long time since I played with these settings, not really a very useful feature imo, the older type petrol addition control handles in the boxes above aren't as dynamic but are probably more useful. Could be useful if a customer has concerns about vsr and wants to run on some percentage of petrol, perhaps a higher percentage of petrol at higher loads... but can make fuelling less accurate because it can only assume that if (say) 20% addition is added gas injector pulse should be 80% of map figure.. when pulsing gas injectors for 80% of map intended gas figure is unlikely to give exactly 80% of intended gas and even pulsing petrol injectors for 20% of petrol map's intended isn't likely to give 20% of intended petrol, these aspects combined with reducers not being 100% pressure stable causing the percentage rates to change for the same driving condition.

Apart from the vsr prevention use scenario above I think the only time I could imagine using it would be to fudge a 'gas pressure let off' facility.. Some engines such as early closed loop pulsed injection BMW straight 6s / V12s handle stepping off the accelerator from high load unusually, they cut off fuel injection while keeping the electronic throttle open. If you had such vehicle fitted with turbos or a supercharger then with 1.5bar boost and 1.5 bar working pressure there'd be 3 bar gas pressure (above atmospheric) and when gas injection did first start again after lift off there'd be a lot of engine vacuum so most of that 3bar pressure would be delta pressure which could cause problems for gas injectors... So setting a high percentage of petrol addition at such high gas pressure would allow the engine to run mostly on petrol but with the gas injectors pulsing to bleed the high pressure until more normal gas delta pressure returned.

Simon

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Last edited by LPGC on Sun May 13, 2018 6:16 pm, edited 1 time in total.

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 Post subject: Re: king new software
PostPosted: Sun May 13, 2018 5:29 pm 
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Joined: Thu Apr 11, 2013 9:39 am
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ok that's far too technical for me
at 126k miles i think i am not too fussed about vsr, expecially since the fantastic prince engine uses a fair amount of oil.
I use around 1L every 1500 miles, until around 100k it was using about 1L/3500 miles which was much better, then suddenly it started to use more oil, a lot more, like 1L/300miles because the pcv valve had cracked.
I changed it with a new one, but engine never went back to the original oil usage.
My concerns is where the oil is going, probably in the intake, and with 100% gas I cannot clean the inlet valve and I probaly end with a situation similar to GDI cars..
go figure, the car is still going, but I am not sure how many miles i'll be able to squeeze out of it..hopefully I will get to 160-180k before it starts to drink too much oil..
unfortunately the great german engineering produced a 2stroke petrol car...


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 Post subject: Re: king new software
PostPosted: Sun May 13, 2018 6:15 pm 
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Joined: Mon Jan 23, 2012 12:21 pm
Posts: 1005
Location: Milton Keynes
A compression test might tell you some useful info if you wanted to look into it. Wouldn't have thought it was down to the valves more likely the piston rings allowing too much blow-by and pushing the oil somewhere it isn't wanted. unless its just leaking of course, though you'd usually notice the mess that makes under the car if so.


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 Post subject: Re: king new software
PostPosted: Mon May 14, 2018 6:44 am 
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Joined: Thu Apr 11, 2013 9:39 am
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Hi Brian,
already did the compression test and its "as new" 10.8 bar on every cylinder with the car cold..
the problem with this engine (and with all the BMW 4 cylinders) is that the timing chain is put just below the pcv intake, the chain sprays quite a bit of oil while working, the oil gets sucked by the pcv vacuum and ends up in the intake..
It is a design fault there is nothing much to do..
Blocking the pcv is not an option for me, because my car, being a 2007 has another lovely bmw fault, between 2005 and 2008 bmw used valve seals of sub-standard quality, as a result around 70k miles they harden and start leaking a little. While crankcase pressure is low, with the PCV operating, they do not leak too badly and the car just loses oil via pcv. If the PCV vacuum is missing or worse if the pcv exhaust is closed, the pressure buildup makes them leak like a tap..
So I have a 2stroke car :) a liter of 5w40 every 1500 miles, does bother me, but since it runs fine and I never had to do anything in the car (beside changing a thermostat once and the rear brake calipers) I am keeping it giving the substantial number of merc and bmw I see every day on the hardshoulder waiting for recovery :)

by the way this problem affects all cars using this engine and it is particularly bad in the turbo version (mini and bmw) which has also the very bad habit of snapping the timing chain..


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