VE Table Help

[antus]

You can try and do it, you'll still get target afr in tunerpro, but it'll be harder and more prone to error without the ability to freeze frame things for a good look.

[vc81]

heres a target AFR for you compared to a wideband. (bottom monitor, red = target afr, green = wideband)

gemini 8psi boost run WSID.jpg

the trick with it is making sure the minimum and maximums in TP5 adx are all the same so they scale exactly the same on the monitor. as you can see TAF and AWB on the axis have the same numbers in the same spots. and this shows perfectly for me over the 1/4 mile pass that my fueling is pretty closely following the target but could do with some tweaking of the VE tables to get it spot on the whole way.

you also use the target and wideband to work out the percentage offset for VE's then multiply it by current VE to get a histogram of calculated VE which VL400 has added to most adx's I believe.

So how do I adjust the minimum and maximums in the TP5 adx so they are all the same so they scale exactly the same on the monitor?

I take it TAF means target air fuel ratio but what does the A stand for in AWB?

[Tre-Cool]

I'm guessing Actual Wide Band

[Holden202T]

TAF is target air fuel, AWB is analog wideband, the reason they are three letter abbreviation is because the adx is for VL400's data logger which has limits to length, and the wideband is through an analog input on the logger

To change the adx use the two gears icon up the top then go in and find the target afr and wideband items and when you click on them you'll get the options for range etc ...

Also worth noting this is just the limits of the display, and if you find you can't notice enough movement you might need to zoom in so to speak, so instead of 10 - 18 maybe go 11 - 17 etc

[VL400]

Beat me to it while making a picture, but will post it anyway

Edit_ADX_Range.png (83.76 KiB) Viewed 4350 times

[vc81]

Thanks heaps fellas. The last two posts help a lot. So I should make sure the range is set from eg, 10 - 18 on both the wideband & target afr?

[Holden202T]

The numbers don't really matter as long as your graphs stay with-in the limits, the main thing is to make sure both target and wideband use the same values

[vc81]

Ok thanks mate. Can you please explain how to do this - use the target and wideband to work out the percentage offset for VE's then multiply it by current VE to get a histogram of calculated VE which VL400 has added to most adx's I believe.

Is this something to do with the VE by Histogram excel spreadsheet or the wideband converter v1.00 excel spreadsheet? Could you please explain what these spreadsheets are for and how they are used please?
Thanks again for your help.
vc81

[VL400]

Lets go back to basics of what you are changing, hopefully it will then make more sense.

At the end of the day the task of the ECU is to run an engine by injecting some fuel. How much fuel depends on many many factors and requires a few sensors to work out. Going to the absolute basics it really only needs to know the RPM, the MAP and air temp (the ECU follows the ideal gas law if you want to for more detail). You are tuning whats known as a SD (speed density) system.

The ECU is constantly calculating the air entering the engine. From that it can work out how much fuel to inject for the target air/fuel ratio - lets say the target is 14.7:1, that means for every 14.7 parts of air inject 1 part of fuel. By knowing the cylinder size and injector size (from the KINJFLOW term), the pressure (MAP sensor), the air temp entering the cyl (from the MAT) and the RPM its possible to calculate the required pulse width to get the desired air/fuel ratio.

However, an engine does not operate at full efficiency all the time. So the ECU uses the VE table to know how efficient the engine is at each load point (RPM vs MAP). If the VE table is say 50%, then the cylinder is only filled to 50% capacity. The fuel PW is then modified to still try and satisfy the desired AFR - say its 14.7 parts of air to one part of fuel, less air filling the cyl means less fuel will be needed to get the ratio correct. But, as the ECU has no idea what the actual VE is at that load point its your job to tune the table so that the target AFR and actual AFR (from say the wideband) match. Disregarding all temperature corrections for now, once the target and actual AFR match you know the VE you entered is actually what the engine is operating at.

To actually make the change to the VE its a simple calculation...
Required VE = Wideband AFR / Target AFR * current VE

This is what the CalcVE item is doing in the ADX.

As an example..
Target AFR = 14.7:1
Wideband AFR = 12.0:1
Current VE = 80%

Required VE = 12 / 14.7 * 80 = 65.3%

The original VE was 80%, but as the engine was running richer than what the ECU was trying to command you know then that the VE needed to be lower - the ECU was being told that 80% of the cyl was being filled so was injecting enough fuel to allow for that.

[vc81]

Thanks for breaking it down to the basics vl400. So how do I use the CalcVE item in the adx? Do I manually have to do something with it or does it do something automatically?
Also how do I use the attached spreadsheets?