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AE Fuel Film

Started by fphil, October 09, 2013, 10:29:05 AM

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fphil

Hi,
Does someone knows how the Fuel Film factor are taken into account compared with the general settings of the AE?
On my wiki page I have posted some graphics I have got after tuning the first setting (10%,0.86ms)

(plot in the crank angle domain 1revolution = 720°.lambda scale is 30*lambda_30, tpsDOT are % opening/rev)
I do not know what I need more and what to improve ?

fphil

I found some quite readable info on the historical page
http://www.diy-efi.org/efi332/equations/algorith.htm
as referenced by Vems Wiki

gunni

I´m not sure how the fuel film behaves as I tried to identify it but never got any measurable PW results.

I´m not sure what kind of "delay" there is in activating AE in VEMS , does it wait until after the cycle to update or can it be updated mid cycle, or even worse, does it wait X many cycles..

Are you having drivability issues? Almost always a problem of not enough fuel

fphil

"Are you having drivability issues? Almost always a problem of not enough fuel"

No, no, it runs alright, I can say better than with the OEM ecu (Weber IAW), just interested in the film matter since manifold fluid flow is not something easy to understand and to modelize.

Vems compensation seems to come quite fast and quite well. You can see that from the plots, per example plot 41, lambda is 1+ before  the start of tpsDOT = 2%/cycle (scale on the plot is 30*lambda-30) and goes richer just after the TP opened instead of coming lean on a surge. 

However I did not tune the AE that much.  Even without the AE, the engine did not cough when accelerating.
It is an easy engine 2L,  comp. 1/7.8, max torque à 5500rpm, 220 hp @175 kPa. For the present time I run rich for every (rpm,map)

gunni

I haven´t been able to replicate any specific pulsewidth from the fuel film factors.

But the AE stuff is easy to monitor and to get right.