MembersPage/EmilMalmsten/AudiS (2006-03-16 04:43:08)

Trigger setup for Audi S4, 5cyl Direct Fire engine

Audi 2,2T AAN engine

1.0.25 + MT r027

Config http://linkopingsmotorsport.se/config.txt

Tables http://linkopingsmotorsport.se/tables.txt

Datalog http://linkopingsmotorsport.se/datalog200511281817.xls

Datalog http://linkopingsmotorsport.se/datalog200511281819.xls

Notice drop in RPM, engine never catches up

TODO:

Possible causes

These explain everything we've seen!

vr_signal.gif

shows

Too high amplitude at the missing tooth.

Eliminating this would likely help a lot. The first attempt did not help. Unfortunately the welding has different magnetic characteristics, so it's a bit different that if the wheel had been machined that way.

You can fill up the small corner-step which leads to the tooth after the gap (considering the rotational direction. before the gap: we don't care):

triggerwheel_gap_mod_s4_hint.jpg

You can even make the fill (the red part) muuuucccch longer than on the pic, eg. 1.5 tooth long, to span halfway until the gap-mid, don't be afraid of it. The patch you applied seems to have much lower B/H than the base material (not the same material, right?). Even if you filled most of the gap with that material, the the pulse would be just a tiny bit smaller than the normal teeth.

Note: no need to mount the wheel on the engine to measure the missing-tooth amplitude. (change the voltage divider 100k/1k to 10k/1k if the notebook sees too low signal)

Also, amplitude varies a lot for normal teeth as well, likely because excentric shaft or wheel. Amplitude is bigger where the sensor sees higher "magnetic flux rate of change", eg. because wheel gets closer to the sensor or has higher magnetic permittivity (mu=B/H).

Most likely reasons:

Note: wheel must be mounted on the engine to measure if shaft is cenetered.

TODO: Is the sensor mounting bracket firm ?

The 2 captured waveforms show exactly the same pattern, so it is very unlikely to be caused by vibration (why would the sensor vibrate exactly with that phase?).

Dropped:


See also