G4+ Sequential gearbox Downshift blip E-Throttle

[VtrSp1]

In this time of Lockdown, i have go forward with a new improve to my race car. I done this, installing a E-throttle for do a downshift due to sequential gearbox with barrell position and loadcell knob.

In the past year i have the Upshift gearbox cut and all work good after few initial trouble with setting and fine tuning.

The E-throttle work very good and i setup very well, i need some fine tuning on E-throttle setting but is quite easy.

In normal operation it's ok, but with a Blip to 20% i have a few count on Tp target error accumulator, i think it's the PID setting . I have used a Honda K20 E-throttle and the PID setting provided in G4+ Help manual but i think the P is too high , so i try to reduce them to 7 and do a new test.

The other question is about the sequential gearbox control for the Downshift Blip.

- I read in other post that for a true Overrun downshift blip , the better is to shut off the Overrun fuel cut in decelleration ..this is right? This because there isn't too much time to re-activate the fuel and do the blip..?

- In the Gearbox control setting , the TP LOW LOCKOUT , need to be set to 0 for allow the Downshift blip ?  Normally the Overrun downshift blip start with the Throttle to 0, so if i set the TP LOW LOCKOUT at value > than 0, the ecu allow only Upshift? Or this is  a bug not fixed about this setting?

- The DRIVE/OVERRUN TP, need also set to 0? I have do a few test with no load to the wheels and the downshift blip work only if i set this value to 0...The test was do in 2nd gear and downshift to 1st...if i set the DRIVE /OVERRUN TP at value > than 0, the throttle blip don't work.

 

 

 

 

[Adamw]

I have never tried TP Low lockout at zero, I just looked at the last car I done downshift blip and I had TP low lockout set to 2%, (in this car the throttle didnt go below about 5% in normal use though, I see yours goes down to 0%, it might pay to open that up a little as the throttle motors often break gears if you slam them shut like that. 

 

21 minutes ago, VtrSp1 said:

The DRIVE/OVERRUN TP, need also set to 0? I have do a few test with no load to the wheels and the downshift blip work only if i set this value to 0...The test was do in 2nd gear and downshift to 1st...if i set the DRIVE /OVERRUN TP at value > than 0, the throttle blip don't work.

No, this should be higher than your normal idle TP.  Im not sure why it is not working for you, it may be related to the TP lockout above set to zero.  I may need to see a log.  But in my last set up the drive/overrun TP is set to 8%.  This means anything less that 8% TP is considered an overrun downshift (will blip), any gear shift with more than 8% TP is considered a driven downshift (ign cut).  

 

For your E-throttle error, yes I think it is PID too.  Too much P or D.  

[VtrSp1]

@Adamw , my throttle body position (Tp Main) at idle is 3.8-4% and idle stable at 1300 rpm that is the target with 80°C coolant temp.

 

I attach a log..

i need to go from e-throttle closed loop idle to open loop because i have a ISC CL trim strange when i do the blip...it work as trim very negative and the engine shut off because the throttle go to 0%

 

 

@Adamw , i attach the calibration so you can see my setting need to be testing tomorrow

 

[Adamw]

The last one I done also had CL E-throttle idle and I didnt see this odd effect you have going on.  Your CL idle should normally be locked out by the RPM lockout?  The speed lockout should take care of it when moving also.  I might need to see your .pclr file too.

I only have an ecu log with not all parameters recorded, but you can see in this pic below TP main is sitting at 4.9% during over-run which was normal idle position.

[VtrSp1]

I have attached the calibration used for the log

i have another log

The car is at 0 speed, clutch pressed and in 2nd gear. I use the lever for downshift for see if the blip work

@Adamw

 

 

@Adamw in The log Test 2 at frame 2.18 can you see the issue, blip throttle, ISC CL go down to -3% and engine stall..

[Adamw]

Im not sure why closed loop idle is still working when RPM is above the lockout, but I think it is because idle conditions were still meet prior to RPM increasing.  Im sure under real life conditions (ie, when you do a blip from above normal idle conditions) it will work fine.

Not really related to gear shift, but I have changed your E-throttle target table and idle base position table in the attached file as it will work better like this - the general idea is you want most throttle opening to come from the E-throttle target and only a small trim for temperature changes in the idle base position table.  Also as I mentioned earlier you dont want zeros in your E-throttle target table as you will break the motor gears quickly due to undershoot.

If you jack the drive wheels up off the ground you will be able to test downshift blip better.  

1539258059_newmods-EThrottle idle and target changed.pclr

[VtrSp1]

@Adamw, ok i have try with the wheels up off the ground and the downshift blip work!

I have a little high error accumulator on E-throttle when i do the blip or i press very fast the throttle pedal..

I have work to the PID... The P from 8 to 6 and D from 60 to 50 don't show me any improvement, but i see with a little high I from 0.030 to 0.1 the error is very low

i attach the log with the last throttle PID setting that show me a low number of error during the Blip .. this is a acceptable errore range?

In the log i do 3 downshift..

 

 

 

 

 

 

[Adamw]

10 hours ago, VtrSp1 said:

i attach the log with the last throttle PID setting that show me a low number of error during the Blip .. this is a acceptable errore range?

Im normally happy if the error accumulator stays below about 10 counts during heavy on/off throttle use, so yours looks ok I think.

 

 

[VtrSp1]

@Adamw

Ok so i can be happy with my setup.

I have another issue that bores me, i  do a test with engine off and set 100% throttle target at 0% pedal for see if the throttle blade is flat horizontally. I found that is at 95% of throttle Body and it's ok. When in the throttle target table i set the idle value (3.5 %) the blade close, go below the target and next go high. So i say that in the normal use/race use is very impossible because the foot isn't fast as a number...but i'm happy if you can take a look at log attached at frame 3.13.400

 

 

Log 2020-04-30 7;51;04 pm.llg

[Adamw]

It is pretty typical to see a small amount of overshoot or undershoot from a large step change.  With PID control there is always a compromise between response speed, overshoot and stability.  So yes, you could get less undershoot by increasing derivative, but this will also slow down the response speed.  To me yours looks pretty good, at 3:29 you have maybe a little more oscillation than I would normally see, so you may be able to improve that a little with further experimentation. 

[VtrSp1]

@Adamw thanks a lot for help me and waste your time for that...

The oscillation in the frame 3:29 it's possible to control with more tuning on the Integral gain?

From my experience, the Integral gain in PID setup help to control the oscillation , or i can reduce the Proportional ?

 

And a question about the downshift blip in the sequential gearbox with gear lever load knob cell , this based with your experience, is better dab the clutch or i can do the downshift clutchless?

I have read different thinks about this, many tuners do that and many gearbox brand don't allow that with a gear lever but only with paddle shift

[Adamw]

10 hours ago, VtrSp1 said:

The oscillation in the frame 3:29 it's possible to control with more tuning on the Integral gain?

From my experience, the Integral gain in PID setup help to control the oscillation , or i can reduce the Proportional ?

Prop, Int & D all need to work in harmony so it could be any of them causing it.  I suspect increasing D may help but it really just needs a little experimentation now.

 

10 hours ago, VtrSp1 said:

And a question about the downshift blip in the sequential gearbox with gear lever load knob cell , this based with your experience, is better dab the clutch or i can do the downshift clutchless?

I have read different thinks about this, many tuners do that and many gearbox brand don't allow that with a gear lever but only with paddle shift

You will probably still need clutch for a lever shifted gearbox.  The differenece is with a strain gauge gear lever the blip isnt initiated until you have already started to moved the gear lever.  With paddle shift the ecu can initiate the blip as soon as you pull the paddle, then it will wait a little for the engine to respond before it activates the shift actuator.  You can do clutchless downshift with a gear lever but it does take a different driving style, you have to keep weight on the gear lever for some extra time until the shift is complete.  This is not instinctive so some drivers dont like it.