If I got it right it's now ready for testing. I'll do some testing later today. Should be avaible in 1.0.79 and also easy migration to 1.1.x.
Menus would look like this:
http://kotisivu.dnainternet.net/sakrkorh/vems/rpmvsamount.png
http://kotisivu.dnainternet.net/sakrkorh/vems/dotratevsscale.png
Any suggestions for gauges etc?
That enrichment model looks good. I have always suggested that we have a separate "tip-in from idle" setup but this covers "tip-in from idle" without any extras.
My previous estimate that a 4X4 table is enough was based on this idle area. I think tha we need 5-6 rpm sites without the special idle condition. If that would be simple to arrange it would be good.
I expect to have a loadsite just below idle and one at maybe 1300 rpm, where the AE in the idle loadsite is probably 3-5 times higher then the base transient fuel at 1300rpm.
AE is affected by load:
I think that a 3d table with load and rpm is not better then the 2D rpm table. I have always found that you always need a lot more acc enrichment if you tip-in from a high vaccum then if you tip in from almost ambient pressure. I always find that the correct AE for low loads will overfuel heavily if you tip in from, 80-90kPa to boost. This is most likely related to the fact that you have less fuel on the walls at high vaccum then you have at lower vaccum but with a limit above which more fuel is not puddling on the walls.
Considering the separate "tip-in from fuelcut" condition and the lower demand under boost I think that we need 5-6 loadsites for MAP as well.
Having a 2D load compensation table would probably work in most cases but the added flexibility of the 3D RPM/Load table is probably worth the effort.
Overrun fuelcut:
We also have a special case with the overrun fuelcut, when tipping in from an overrun fuelcut condition we need a lot more fuel then if we tip in from just above overrun fuelcut. When going into overrun fuelcut the walls will quickly be purged from fuel, this fuel has to be replaced when the fuelcut is removed again. This will have to be added to the AE if there is a tip-in.
Transient fueling will also be simplified greatly if the overrun fuelcut is delayed for a configurable time. 1 second would probably be a good fixed value.
Updating load based AE:
While tipping in the load (usually MAP) will change quickly. I THINK that the AE amount should be updated upward if the load table says so but that it should not be updated downward. I base this on the fact that if you do a tip-in from overrun fuelcut you really need all that extra fuel specified down at 20kPa, negating this with the low AE specified at 100kPa 0.1seconds later will cause problems.
As long as the decay is the same for all AE it would be enough to just compare the current acc enrich amount with the new one that is calculated, if it's higher it's applied and if it's lower it's ignored. If we need to use variable decay rates in the future I can only see that we need to make an array where all the different transients are calculated and where the biggest one is applied.
Meanwhile I'm looking forward to trying 1.0.79 with this new AE fuel stratergy in my car.
Jörgen Karlsson
Gothenburg, Sweden.
