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josey

E-Throttle PID setup

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Hi guys,

i need help fine tuning PID settings on my ethrottle.

maybe problem is that i have too big throttle body and too small engine :(

So it is 2.0 liters engine, and 75mm throttle body (audi - vw W12 6.0 liter TB)

 

in open loop i get kind of smooth idle but cant get it in closed loop.

this post can be used as tutorial?

 

my settings are default

proportional gain: 7

Integral gain: 0.145

Derivative gain: 25

and idle is bit jumpy (unstable, it overshooting idle target for 400rpm or more it drops below 800 and than jumps to 1200)

DBW idle position is about 3.0% for 1000rpm on fully warmed engine (3.1 is about 1100)

by searching forum, i found few topics, and i guess lowering integral gain to about 0.4-0.5 should solve the problem ?

 

Please, can you quick guide me how to properly setup DBW to get smooth idle and have good response on throttle?

Also can you help me to get slow return to idle after full throttle?

What is happening now is, in neutral when i depress throttle, rpm drops fast and drops below idle target and engine almost shuts down. (i can achieve this in main dbw table?)

 

thanks

 

 

 

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Hi Josey,

Before going into the idle control configuration you need to make sure that the TPS is tracking the E-throttle target correctly. The best way to see this is using PCLogging and the timeplot. Can you record a PCLog where you change throttle position rapidly and then more slowly, then take a couple of screenshots from the timeplot and post them here.

Here is an example of what yours might look like:

 

E-throttle timeplot.PNG

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so im rising proportional gain untill i get good response ?

then im braking it with derivative gian when it overshoot?

and than fine tune it / trim it with integral gain?

 

for now with this settings i have very good throttle response.

P: 7

I: 0.145

D: 25

 

thanks Scott i will give a try and let you know

 

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here are 3 logs

this is

P: 6

I: 0.05

D: 25

QnvgEDn.jpg

 

two logs with

P: 7

I:0.145

D: 25

vj2GRgB.jpgYfD7gs5.jpg

 

this looks same for me on

6 - 0.05 - 25 and 7 - 0.145 - 25 :(

 

 

 

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When you are setting it up. Back the max target back from 100% so that you can see an over shoot if it happens.

Other wise the throttle might be wanting to over shoot the target but cant as it is stopped mechanically.

Be sure to hit enter after changing the values to have them take effect.

 

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Hi josey,

Looking at the last screenshots the tracking of the throttle plate to the target looks pretty good, no massive overshoots and oscillations.

Now try and see if you can get the idle stable using open loop idle speed control.

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thing is that in open loop is stable

as soon i change settings to closed loop idle becomes unstable, and its overshooting idle target.

and motor dc% is same for open/ closed loop. 

 

that is why i open this topic and asking for help. 

afr is stable at about 14.2-14.7 

ign 14deg

 

 

 

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Can you record a PCLog of the idle on closed loop and upload it here with your base-map? If the file is too large to upload please email it to us at tech@linkecu.com. If you do email it please include a link to this thread so we can know the background.

Thanks,

Scott.

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Hi lekonna, 

PCLink Help > Wiring Information > Output Wiring > E-Throttle > Specific E-Throttle Applications has some pinout and setup values for various e-throttle bodies.

Basically any e-throttle body that outputs two different analog voltages in the range of 0v to 5v, and uses a motor that draws less than 10 amps should work.

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ok i think my probčlems are related with that my e-throttle works only in "setup mode" it cant work in ON mode.

problem described here

today situation  -

somehow i get idle in closed loop to work smooth,

and i get engine running for half hour,

fully warmed up, water 94c, oil 90c

engine is idling smooth  on 1000rpm +- 50rpm at 2.6-2.8% TPS

than i rev it to redline, and release throttle,

what happened, i noticed  TPS closed to near 0% although in ethrottle target table value is 2.5%

and than again CL idle control started to play from 1.5% to about 4%, ok, why 1.5% when minimum value is 2.5% in ethrottle target table?

ok first question on my mind was, why TPS is dropping below 2.5% at first place?

 

then i change e-throttle mode from "setup mode" to ON

and e-throttle just shut down, and tps moved to if i recall 3.9% which is some default value when dbw motor is not powered.

F4 - pressing throttle pedal - nothing, shut down engine, start it again, nothing, throttle is dead, change from "ON" to "setup mode", DBW motor started again and returned TP to 2.7% and smooth 1000rpm.

 

 

 

 

ok, so DBW is not working in ON mode for me i dont care, but how can i prevent TP to drop below desired value? in this case lets say 2.5%? this is actually my main question now.

and is really my problem in e-throttle mode, because it cant work in ON mode?

 

thanks

 

 

 

Edited by josey

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In ON mode all the e-throttle safety limits are applied, so for example there is a different in % between the sub and main channels on either the TPS or APS then the ECU will shut down the e-throttle. Have a look and see which fault code comes up when you switch from Setup mode to ON mode. 

When Idle control is in closed loop mode a closed loop trim gets applied on top of the base position from the e-throttle target table and Idle base position table. This closed loop trim is trying to achieve the target RPM you have specified in the Idle Target RPM table, and it's value can be positive or negative (as required). 

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Scott 

i understand you completely

but i dont understand why is throttle blade dropping below 2.5%? 

that should be something like screw on mechanical TB? 

ill try to play with settings little bit, 

thanks Scott

 

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If the CL Trim was a large enough negative value then the TP(Main) reading could go less than the value in the e-throttle table. If you post a PClog of the problem happening and your base-map we'll be able to advise.

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