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IMPORTANT: enter the case-INsensitive alphabetic (no numbers) code AND WRITE SOME SHORT summary of changes (below) if you are saving changes. (not required for previewing changes). Wiki-spamming is not tolerated, will be removed, so it does NOT even show up in history. Spammers go away now. Visit Preferences to set your user name Summary of change: injector angle notes: * tuners think in term of the "angular position of the end of injection pulse", BTDC (eg. 430 crankdeg BTDC) ** however obviously the start of the injection pulse is scheduled and activated first ** and the length of the injection pulse is much more important (and respected) than the angular position of the end of the pulse. This more significant effect when RPM changes, it's just good to remember. * while it is referenced from a future fictive event (TDC), it is always actually actuated from a past real event. ** eg. the ECU firmware sees pulses from primary trigger (and secondary trigger, but timing in general is performed from primary trigger, because it would be stupid otherwise - crank is much more precise, cam sloppiness is known.) ** ECU firmware can only time from past input pulses (eg. that happened 70crankdeg before previous TDC), not from future pulses, and never from fictive (TDC, which is "TDC after the trigger" later than the "actual trigger tooth"). * because it is more versatile this way, the tables can be rotated (by 1..2..N events). This is versatile, and intentional, but '''if the installer choses to rotate''' (often as convenience if wiring was not aligned to actual sequence start), it '''might effect the angle''' (eg. by 1..2..N full events). ** This can be useful: eg. 430..500 deg values (~220..290 deg after prev TDC) can be actuated more precisely (also when RPM is not constant) than lower injangle values ** the display of cyl number is just optical (as set by the tuner, the ECU and VT has no way to verify if it is correct, nor does it care... it will activate the outputs in order, and installer's responsibility to wire to actuators in correct order) ---- '''Investigating injector timing angles''' * if being represented correctly in the ECU (and VT) ** if VT help page needs some more notes about it (eg. effect of rotating tables) '''Format of any report abstract, for any questioned point of vemslog is:''' * RPM: ... * spark advance: ... crankdeg * start of injangle is: ... after prev triggertooth (or after ign deactivation) * length of injection pulse: ... msec measured (vs commanded: ... msec) * '''end of injangle is''': ... degree after prev triggertooth, ** - "TDC after the trigger" = A = ... degree after prev TDC ** B = 720 - A = ... degree before next (future) TDC ** which is N events after/before the expected angular position of "end of injpulse" ** does it match configured table rotation ? The injection angle table should be BTDC of "cylinder" (ignout related to given injector output, considering any table rotation) "physical" TDC (actually configured "TDC after the trigger" value) on the compression stroke. On a bench setup with cam setup, 24 crank + 1 cam at 1200rpm as supplied by waveform generators Injector output is pin 7 Ignition output is pin 34 Its assumed that the Ignition out angle is the correct one (I sure hope) 90deg TDC after the trigger First trigger tooth 1 When 720deg inj angle and 0deg ignition angle its safe to say that the rising edge for both ignition coil and injector output should be extremely close to each other as they are both supposed to happen at TDC. The injection angle is however controlled by the TDC after the trigger value and not actual cylinder TDC!!!! I think this needs proper explanation as to why this is like this and not to actual TDC This is on 1.2.41 btw. Image 1 below. Red is ignition, Blue is injection Inj angle 360 BTDC, Ignition 0 deg BTDC, 90deg reference angle https://i.imgur.com/tUvdhHt.jpg Image 2 below Inj angle 720 BTDC, Ignition 0deg BTDC, 90deg reference angle https://i.imgur.com/sOcIDDL.jpg Image 3 below Inj angle 720 BTDC, Ignition 0deg BTDC, 25deg reference angle https://i.imgur.com/tAOmC1J.jpg More files http://vems.hu/vemstune/bugreports/reports.php?cmd=view&key=r4vCur Optional: Add document to category: Wiki formatting: * is Bullet list ** Bullet list subentry ... '''Bold''', ---- is horizontal ruler, <code> preformatted text... </code> See wiki editing HELP for tables and other formatting tips and tricks.