[Diy_efi] Estimation of spark advance

[Carsten Beth]

Hi all!

Some time ago I wrote to the list that I build a EFI solution to replace
the mechanically controled system of my motorcycle (Honda GL1000, 1977).
It's a microcontroler based system, which is triggered from hall sensors
and drives IGBTs. The main goal was to create a low cost,  more accurate
replacement without wearout and with the possibility to tune the spark
advance.

Now the EFI is running! I can start the engine and it is running quite
well above 2000 rpm.

The next step is to adjust spark advance. At the moment I use the
mechanical systems original values, respective what I think, what it
should be. The information I actually have, is that the advance should 
be 5° up to 1000 rpm, 37° above 3000 rpm and there sould be a "soft"
transition between 1000 and 3000 rpm. That's not a lot, but maybe all a
mechanical system can do.

Now I think about how to make a good estimation in a theoretical way to
have a quite well running engine over the whole range. Is it possible to
do so? In my opinion the main problem is the unknown time from
triggering an ignition spark to the point where power is developed to 
the crankshaft. I just know the first component, from triggering to
appearance of spark and I know the sparks duration. So the question is,
how long does it takes from spark appearance to power development? Or is
there a better sulution for estimation the spark advance?

Best regards

    Carsten Beth

_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi