Formula help for Calculated Pid

[vetteboy2k]

I am looking to create a calculated pid for .5V = .68 Lambda and 4.5V = 1.36 Lambda

I understand how to type all the information into the calc_pids file I just am unclear on the math behind coming up with the equation

The equation for the AFR .5V = 10 and 4.5V = 20 is
{EXT.AD1} * 2.5 + 8.75

Can anyone help me understand how to come up with the same for the Lambda values :cheers:

[vetteboy2k]

Also is there any way to create a calculated pid for Serial Lambda and Analog Lambda? I tried using B3605 however an error occurred when opening the scan tool

[mr.prick]

Depending on who you ask, Lambda = 14.7AFR
(AFR/14.7) = Lambda
or
{EXT.AD1}*2.5+8.75/14.7
If you have serial just select EXT.WO2LAM1, why convert it to analog?

[vetteboy2k]

Thank you, haha I was way over complicating things!

I now have
factor 0.0 2.0 .2 "{CALC.LAM_FJO} / ({GM.AFR} / 14.7)"

As for the BEN for Serial Lambda, I didn't see a pid for BEN lambda serial so just getting ready for it. There is a BEN for Serial AFR just not Serial Lambda

This is what I will have
factor 0.0 2.0 .2 "{EXT.WO2LAM1} / ({GM.AFR} / 14.7)"

Thank you for your clear headed thinking on this one!

[joecar]

For serial AFR, the pid is BEN1.

[vetteboy2k]

Yes, but what is the BEN for serial LAMBDA?

[vetteboy2k]

I ordered a universal serial cable from TAq cables to hook up to my FJO, in the mean time I am trying to get the analog external 1 working properly. The FJO read 14.55 while V2 when scanning reads 14.11 making dialing things in difficult. What is the next step in dialing in the Analog?

[mr.prick]

For BEN from Lambda you will need another PID
to convert commanded AFR to commanded Lambda:
{GM.AFR}/14.7

Why are you basing everything off of Lambda?
You may end up upside down with all the PID conversions and
the PCM uses EQ {B3601} anyways which is the opposite of Lambda.
Use AFR or EQ for tuning.

[vetteboy2k]

B/c of different fuels and levels of Ethanol and when using methanol as well. Lambda never changes... stoich is stoich

[mr.prick]

Stoich is different between fuels. Stoichiometry (http://en.wikipedia.org/wiki/Stoich#Different_stoichiometries_in_competing_reac tions)
Gasoline 14.7 : 1 — 6.8%
Natural gas 17.2 : 1 9.7 : 1 7.9%
Propane (LP) 15.5 : 1 23.9 : 1 6.45%
Ethanol 9 : 1 — 11.1%
Methanol 6.4 : 1 — 15.6%
Hydrogen 34 : 1 2.39 : 1 2.9%
Diesel 14.6 : 1 — 6.8%

Lambda is going to change and the PID is based off 14.7AFR
You can change this for each fuel type.

[vetteboy2k]

What I meant by that is the sensor doesn't care what fuel your using or what % ethanol you have in your fuel, Its always going to read stoich of that particular fuel at 1.0 lambda.

[joecar]

Yes, but what is the BEN for serial LAMBDA?

You could use this (like Mr.Prick suggested): 14.7 / {GM.AFR} * {EXT.WO2LAM1}

Or you could instead log GM.EQIVRATIO and use this: {GM.EQIVRATIO} * {EXT.WO2LAM1}

And I would display WBO2EQ1 = 1 / {EXT.WO2LAM1} on the dash/chart to avoid confusion...

After using EQ units for a while you get used to them, you'll like EQ better than AFR.

[mr.prick]

Personally I use BEN as a reference,
I don't care what the AFR is at the moment as much as I care if it is what it should be.
I don't worry about this anymore. :)

[vetteboy2k]

Has anyone ever got a FJO wideband to read serial into the V2? I bought a universal cable from taq and hooked up the wires tonight but I get Controller not found.

I swapped Tx and Rx and still the same Controller not found message.

I thought I read somewhere that FJO's serial would not work, yet I see that its supported in the V2 for serial WB02 and Paul said it is supported as well ?

[vetteboy2k]

The FJO serial wide band protocol is supported on FlashScan. Make sure you have the latest firmware. A new firmware version (V2.06.01) will be available soon. It contains some small display fix-ups that may affect the serial data display.

Page 15 of the FJO Installation and User Manual shows a wiring diagram.

Regards
Paul

http://forum.efilive.com/showpost.php?p=80112&postcount=11

[vetteboy2k]

Measuring the analog voltage not connected = 4.41 and connected = 4.11 therefor the offset 4.11/4.41=.931973 How would I enter that into my calc pid. It keeps coming up as an invalid. Below is the error. How should I have this calculated or written in the calc pid to show properly?

FJO Analog AFR {CALC.AFR_FJO}

Expression:
AFR = ({EXT.AD1} / .931973) * 2.5 + 8.75
is NOT valid because:
Syntax error: ".", position 14.

PID value cannot be determined because
the following error would occur:
Expression not valid: Syntax error: ".", position 14.

***Looks like I got it, it needed a 0 in front of the decimal AFR = ({EXT.AD1} / 0.931973) * 2.5 + 8.75

[mr.prick]

You may want to calibrate your AD's or at least check them,
you shouldn't need to add an offset for the V2.

[whackem04]

can somebody make a sticky about how to edit the Calcuated.Pids the right way and how to write formulas.
thanks

[joecar]

can somebody make a sticky about how to edit the Calcuated.Pids the right way and how to write formulas.
thanksCalculated PIDs:
showthread.php?t=132 (http://forum.efilive.com/showthread.php?t=132)
showthread.php?t=130 (http://forum.efilive.com/showthread.php?t=130)
showthread.php?t=10 (http://forum.efilive.com/showthread.php?t=10)

[Arash]

Measuring the analog voltage not connected = 4.41 and connected = 4.11 therefor the offset 4.11/4.41=.931973 How would I enter that into my calc pid. It keeps coming up as an invalid. Below is the error. How should I have this calculated or written in the calc pid to show properly?

FJO Analog AFR {CALC.AFR_FJO}

Expression:
AFR = ({EXT.AD1} / .931973) * 2.5 + 8.75
is NOT valid because:
Syntax error: ".", position 14.

PID value cannot be determined because
the following error would occur:
Expression not valid: Syntax error: ".", position 14.

***Looks like I got it, it needed a 0 in front of the decimal AFR = ({EXT.AD1} / 0.931973) * 2.5 + 8.75


Based on the formula för a liear equation (y = kx + n), in this case, I would use "n" to adjust for any offset.

So the equation in your case would translate into:

y = lambda
k = line slope
x = voltage
n = vertical offset = the point at the y-axis where the line crosses it

So by adjusting the n-number, you could offset the whole line up or down.

If you have an analog voltage number from the manufacturer for e.g. not connected/connected, I would just compare it with your current reading and insert that offset on to the n-value that was current for you base line lambda calibration.

Is that making any sense? :)