MembersPage/FPhil/OddFireWastedSparkEvilStartUp

Latest summary:

VEMS team implemented a special firmware solution for Maserati startup

This page was used for conversation during the implementation and testing, mostly historical now. We will do some cleanup on MembersPage/OddFireSixCyl and post good config (and related ign/inj output wiring for the Maserati firing order).


..July 2012..

I did the full install of the wasted spark ignition on the engine biturbo, the injection being still done by the OEM IAW Weber ecu of the biturbo. The coil I used was the Bosch 3x2.

I had run the Vems ignition through the distributor for about 3000 km. I made the OEM Microplex Marelli ignition ecu (2 oem ecus : one for the injection, one for the ignition) to run in // with Vems and I got a switch to commute the origin of the firing signal to the coils (there are 2 on the biturbo). I did so for two purposes:

1) to keep the benefit of the knock control of Microplex

2) to start the engine faster in a quarter of a turn with the Microplex instead of the 2 revolutions and more( yes 4 pi) given by Vems ( fw <= 1.2.5 , that was before the "kickstart" implementation ).

There has been some discussion about this sluggish start here http://www.vems.hu/wiki/index.php?action=find&find=MembersPage%2FFPhil%2FInstall where one might say that DIS was the cause of it. However without DIS I get the same results and even worse because of the wasted sparks

Wasted spark

Wasted spark for this odd engine is not obvious. The best that one can do is to pair cylinders in such a way that one cylinder is TDC and the other one is 30 deg admission.

I previously done some successful testing by firing 4 cylinders through the DIS and 2 directly wasted spark from the Bosch coil.

Results

Config : Vems Maserati config (see MembersPage/OddFireSixCyl) :TDC delay after trigger is 127deg, spark delays are 3,33,3,33,3,33, (TDC = 130 deg is not allowed), spark advance is 10 deg.

The test is done by increasing from zero the level of the z012 triggers signals.

benchstartup.jpg

One sees:

- the 2 sec trig from the cam pulley per each revolution (4 pi)

- the 6 pairs of prim trig per each revolution: 3 pairs are on the crank pulley 90-30-90-30-90-30

- odd firing 150-90-150-90-150-90

- first fire after 2 revolutions (and more)

-> It is unclear to tell which sec trig from the cam pair is used

-> I checked another config: TDC delay after trigger 10 deg, spark delay 30,0,30,0,30,0 which should give the same. For some reason, the fire comes 30 deg sooner.