ms2extra 3.4.0 and earlier MAF Load PW calculation

[MercyFlush]

Hi all,

First post here but I figured it was needed.

a bit of background, I'm currently doing my Honours thesis on indirect calibration of MAF sensor Transfer Functions (TF) (Or response curves if you will) using my car and a DIYPNP with ms2e 3.3.3 on it (So I'll just say I'm not sure if it's been fixed yet or not, but I don't ahve the time to update to the new version just yet).

During my thesis I have had to calculated the entire process chain of calculating fueling this is from MAF to MAFLOAD to PW to Dutycycle etc. Anyway, I was going by what was written in the MSextra 'Setting Up' documentation under the fuel calculations appendix as follows

PW = DT + (ReqFuel * Stoich/AFRtarget * MAFload_no_air * corrections)

Now, this IS correct, HOWEVER it is ONLY correct when 'Incorporate AFR Targets' is checked. This is WRONG in my opinion as 'Incorporate AFR Targets' is supposed to be for the VE tables (which are not used in MAF mode anyway) so the way I see it either the documentation needs to be updated OR MAF mode needs to 'Incorporate AFR Targets' by default.

I mean whats the point of having a MAF mode where you have to de-calibrate the MAF to get your desired AFR. AFR Targets SHOULD be used to ensure that the MAF TF retains its accuracy, because it's SO much easier to have a calibrated MAF TF and just change the commanded AFR to get your desired exhaust AFR rather than have to mess round with trim tables etc.

Sorry for the rant, this was a real problem for my calculations but at least I know why it was working incorrectly.

FWIW, I can now calculated a calibrated MAF TF from a single datalog in about 2 minutes, I hope to have an implementation one day after I publish the paper.

I look forward to what people think about this,
Sam.

[ol boy]

By turning off afr you can concentrate on tweeking the TC to get to say 14.7 afr. In the higher load areas you can assume the curve is correct whcih would require the afr correction. I had also used the VE trim table to correct weirdness in high rpm with very low load(decel) conditions. Some might shoot for 14.7 everywhere including wot. They would have no need for include afr.

The nice thing or a curse with MS is you can turn every correcrion off or have everything pushing and pulling the tune around and everything inbetween. You can also switch on or off MAT correction when using MAF.

[MercyFlush]

By turning off afr you can concentrate on tweeking the TC to get to say 14.7 afr. In the higher load areas you can assume the curve is correct whcih would require the afr correction. I had also used the VE trim table to correct weirdness in high rpm with very low load(decel) conditions. Some might shoot for 14.7 everywhere including wot. They would have no need for include afr.

The nice thing or a curse with MS is you can turn every correcrion off or have everything pushing and pulling the tune around and everything inbetween. You can also switch on or off MAT correction when using MAF.

Yeah I hear what you're saying, It can be helpful to not have it in some cases but the point I was trying to make was the documentation is wrong. It reads as though the AFR Table is always in use for MAF, and the tooltip for 'Incorporate AFR Tables' only mentions VE tables as does the MSextra documentation
So I was just suggesting to either fix the documentation or to maybe change how the AFR Tables are turned on or off as currently it's no surprise people get confused as something that says only effects VE tables also effects MAF etc. which it should not. Cheers

[muythaibxr]

By default incorporate AFR is on...

[MercyFlush]

By default incorporate AFR is on...

Yeah I understand that, but I'm not sure you get what I'm saying still..

The tooltip for 'Incorporate AFR Tables' only mentions VE tables as does the MSextra documentation

That's as simple as I can put it. I don't know if the Tuner Studio tooltips can be updated or not, I'm just trying to point out a problem I noticed.
If you aren't interested in fixing it or don't care that the documentation does not explain that 'Incorporate AFR Tables' does not only effect VE tables then that's fine by me, I'm just trying to help align the documentation with the implementation.

[muythaibxr]

Ah, you are just saying the docs need updating. That is probably true!

[jsmcortina]

Incorporate AFR target needs to be enabled for MAF mode to operate as expected. I've added a note to the tooltip for the next release. Manuals to follow.

James