B234R
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« Reply #90 on: April 06, 2012, 07:13:30 AM »
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very true, but it underlines what I mean: there is no simple "factor" to calculate the flame speed depending on boost. you need to determine it on experience or dyno. Of course. If it would be possible to calculate optimum ignition angles in real time with a few given measurements, then ECU developers would have integrated an algo for that a long time ago. Instead even recent systems use dozens of tables, which need to be applicated by the calibration engineer. I'm pretty sure you can model engine physics well enough to get useable ignition angles from a model, but that needs serious computing power and elaborate calculations. Way beyond any feasible DIY approach and that is why all calculators and interpolation/extrapolation approaches to calculate stuff "easily" are useless. yes, I would like to have that proved  "IMO" and "should" is no physical law. and indeed it seems to neutralize each other. many tunes (not only me7) work fine by increasing boost and changing lambda significantly, but not touching ignition. Yes, those tunes work "somehow". The word fine does not belong anywhere near that sentence ;-) The reason is simple, an SI engines works "somehow" with a rather broad variance in operating parameters. But making stuff optimal is a whole different game. I somehow miss the old days when ECUs didn't have these clever knock and component protection schemes, that would have made a lot of tuners much more humble. The trail of detonated engines would have put their crap out of busines much sooner! |
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TTQS
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« Reply #91 on: April 06, 2012, 10:59:54 AM »
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very true, but it underlines what I mean: there is no simple "factor" to calculate the flame speed depending on boost. you need to determine it on experience or dyno. yes, I would like to have that proved "IMO" and "should" is no physical law. and indeed it seems to neutralize each other. many tunes (not only me7) work fine by increasing boost and changing lambda significantly, but not touching ignition. A quick Google search again reveals that the thermodynamics and flame front velocity in internal combustion engines can be modelled. Have a look at the attached PDF file: "MODELING OF TURBULENT FLAME VELOCITY FOR SPARK IGNITION ENGINES" The following site has Java applets for calculating various ICE thermodynamic parameters. I didn't see flame speed in there, but you could have a play. http://www.engr.colostate.edu/~allan/thermo/page1/page1f.htmlAlso, the physics of an automotive engine with a section on flame speed propagation is covered here: http://mb-soft.com/public2/engine.htmlA couple of equations for calculating the flame front velocity are presented. These show that higher temperatures and pressures increase the flame speed. That's the best I can do in 10 minutes on Google. Hope this helps. TTQS |
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« Last Edit: April 06, 2012, 11:06:07 AM by TTQS »
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phila_dot
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« Reply #92 on: April 06, 2012, 11:48:11 AM »
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I have few small questions:
during part throttle ecu ignores LDRXN and works only in KFMIRL limits?
during wot ecu ignores KFMIRL limits and works only in LDRXN limits?
or LDRXN is applied no matter what, but during wot kfmirl is ignored?
Wat?? rlmx_w is output from LDRXN based on RPM, it is then limited for different conditions and output as rlmax_w. The output from KFMIRL is capped by rlmax_w. As a result, specified load rlsol_w is calculated from KFMIRL but cannot exceed rlmax_w. See %LDRLMX and %MDFUE in the FR. |
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lulu2003
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« Reply #93 on: April 07, 2012, 05:58:02 AM »
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Doug, thanks for the .pdf that seems very close to what I was asking. the initial pressure mostly seems to be in the numerator part of the equation but the further modeling and experiments show different results. So my understanding is: flame speed is not equivalent to pressure in any linear or simple non linear form and need to be calculated or applicated by experiments in a way more complex way. (the other site did not convince me to be very scientific and does some assumptions I don't know. and not only because it also hosts sort of this: http://mb-soft.com/public3/911scien.html) |
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TTQS
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« Reply #94 on: April 07, 2012, 09:35:10 AM »
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Oh dear!  TTQS |
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dantt
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« Reply #95 on: June 30, 2013, 10:20:39 PM »
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Can't argue with that. Well, here goes nothing. [Links now replaced with attachments]. Comments welcome, but please don't savage it because it was conceived as a very basic guide for non-tuning types to get a handle on the topic (and, as I said, is based heavily on the S4 wiki) anyway. I had prepared all the material into forum free text format (many hours spent using Excel macros, etc. to format the tables) so it could be posted up once reviewed and edited. The main document at Revision 1 (23rd September 2011)Understanding ECU Remapping The Audi TT 1.8T Variants - Bosch Motronic ME7.x (Rev 1).pdf (1.09 Mb). Supporting information in MS Excel 2003 workbook:Attached to post ECU Files:Audi TT 1.8T ARY 180 PS 8N0 906 018 BR 0261206439. Audi TT 1.8T BAM 225 PS 8N0 906 018 CB.OLS Audi TT 1.8T BFV 240 PS 8N0 906 018 CA 0261208086 375111.bin Attached to post. Translated funktionsrahmen modulesAny funktionsrahmen modules I have translated manually are on the Nefmoto wiki and on this stickied thread: http://nefariousmotorsports.com/forum/index.php/topic,555.0title,.htmlTTQS great job! Why don't you add an appendix on the launch control? : D |
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nyet
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« Reply #96 on: June 30, 2013, 10:23:44 PM »
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Unfortunately, the document is entirely uneditable, and, as i predicted, became abandonware.
.doc is an utterly useless format, from an information sharing and cooperative effort perspective.
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userpike
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« Reply #97 on: July 01, 2013, 02:10:41 AM »
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Unfortunately, the document is entirely uneditable, and, as i predicted, became abandonware.
.doc is an utterly useless format, from an information sharing and cooperative effort perspective.
I don't understand. If you could have this PDF as a .docx so the content can be edited. You wouldn't be interested? |
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« Last Edit: July 01, 2013, 02:12:52 AM by userpike »
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nyet
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« Reply #98 on: July 01, 2013, 09:26:03 AM »
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There is no good way of collaboratively editing the doc format.
no change history, no merge, no revision control, no rollback
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userpike
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« Reply #99 on: July 01, 2013, 10:15:38 AM »
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There is no good way of collaboratively editing the doc format.
no change history, no merge, no revision control, no rollback
I see your point. What would be the ideal format in your opinion? |
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nyet
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« Reply #100 on: July 01, 2013, 11:32:46 AM »
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wiki or docbook
or, alternatively, a single active curator/author that keeps the document constantly up to date..
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SAgti
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« Reply #101 on: July 20, 2013, 08:22:03 AM »
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Careful - NOOB at work  This is a great document - THANKS. I am right at the very beginning of the learning curve on tuning this! I have read the document a few times now - its a lot to take in, but learning all the time.... I have seen that some guys here have reverse engineered the code running the ECU, even adding map switching to the code etc. With this in mind, I was thinking of something that would add great value to this document/forum to help people understand the ecu and tuning it. It would be awesome to have a given set of inputs - eg Throttle position, engine temp, intake temp etc etc - then have a flow diagram/list of exactly what the ecu does (in what order, calculations, map look ups etc ) with this to arrive at given outputs like injection timing, injection pulse time, throttle plate angle, boost, ignition angle. So on a given ecu, we could follow step by step through the code, see what it does, where it gets info from in the map/eprom. Actually see the values returned and see how they are used to get actual values that will then be used for the motor. This is probably a massive undertaking - probably bigger than I imagine!! But it would really be great. This is exactly the understanding I would love to have eventually - my thinking is if you can do this you will really know what you are doing! Don't flame me too bad - I'm a NOOB  |
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ddillenger
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« Reply #103 on: July 20, 2013, 07:51:22 PM »
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Check out philas map switching routine. It uses the CEL as a knock light, Cruise control map switching, etc, etc. |
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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TTQS
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« Reply #104 on: August 27, 2013, 01:29:23 PM »
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Unfortunately, the document is entirely uneditable, and, as i predicted, became abandonware. The document became abandonware because I stopped frequenting this forum and therefore lost the desire to update it, sorry. My 1999 PhD thesis is also entirely uneditable and therefore abandonware. It is also a standalone piece of work, as this basic "getting you started" guide was meant to be. Why would somebody want to edit information that was in some cases derived from logging on my own car? Don't forget that I contributed all my translated modules to the wiki as well as abandonware versions. As I have explained before, if I wanted to create a wiki, I could have done so, but you had already created the S4 wiki which did the job. I would happily have maintained an ongoing interest, but since I stopped coming here regularly, I have had two children. Also, I was promised by another member a look at the code from a household name commercial big turbo tune. The guy himself was busy with his job and family so it never materialised. That would have helped me contribute and revise the document to gain some more insights. Sorry I couldn't maintain an active presence. TTQS |
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« Last Edit: August 27, 2013, 01:36:41 PM by TTQS »
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