Author Topic: Setting your injector dead time (Injector voltage compensation)  (Read 10198 times)

Offline gunni

  • Hero Member
  • *****
  • Posts: 1464
  • BHP: 36
Everything in the fuel calculations requires correct dead time calculations.

Some injectors come with dead time values, but those values may not be relevant to how VEMS uses them. Aside from the fact that you might not know how the injectors where driven during the testing.

Live mapping the dead time is possible and this is how I do it.

1. Warm up engine and get idling as steadily as possible at lambda 1.0
2. Change the lambda target to 0.8 and press BURN
3. If the mixture becomes richer then 0.8 you need longer dead time, if it´s lean then you need shorter dead time so change the value accordingly by 50
4. Put the target back to 1.0 and press BURN
5. Adjust VE map until it idles at 1.0

Go back to step 2 and repeat until changing the lambda target always results in the lambda being the same.
As you get closer to getting correct lambda values all the time make smaller changes.

Why is this important?

The VE table will be more "correct" , all fuel corrections will have the effect they are designed to have. EGO control will be more accurate
and the engine is easier to map on all accounts.



NOTE : When increasing the dead time during this calibration the mixture will become richer so when putting the lambda target back to 1.0 you will need to remove fuel. If you need to lower dead time the mixture will become leaner then 1.0 when target is set back to 1.0, ideally before doing it give the VE map a little bit extra so that the engine doesn´t see higher then 1.1 lambda as it might stall on you.



Offline se7ensport

  • Full Member
  • ***
  • Posts: 154
  • BHP: 6
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #1 on: March 13, 2014, 03:54:37 am »
Gunni

If this is using simplified, won't this only give one value in the table (the voltage that this is performed at)? so the other figures would need to be calculated, not sure how this is practically achieved.

If this is using traditional, how do you calculate the the effective rampup as it is only the Injector Voltage Compensation that is changed in this process? (I am assuming that Injector Opening Time @ 13.2v = 0 and Rampup voltage compensation = 4080 as per the help files).

Please clarify.

Thanks
Alex

Offline MWfire

  • Hero Member
  • *****
  • Posts: 706
  • BHP: 35
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #2 on: March 14, 2014, 12:04:21 am »
i use lambda 0.9 and 0.8. That give similar power.
If you change lambda  from 1.0 to 0.0 for same rpms you will have more vacuum.

Offline UrSobsessed

  • Jr. Member
  • **
  • Posts: 30
  • BHP: 0
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #3 on: March 15, 2014, 10:01:55 am »
Gunni

If this is using simplified, won't this only give one value in the table (the voltage that this is performed at)? so the other figures would need to be calculated, not sure how this is practically achieved.

If this is using traditional, how do you calculate the the effective rampup as it is only the Injector Voltage Compensation that is changed in this process? (I am assuming that Injector Opening Time @ 13.2v = 0 and Rampup voltage compensation = 4080 as per the help files).

Please clarify.

Thanks
Alex

This is my question also.  Perhaps a bit more info into how VEMS uses the deadtime values would really help also.

Thanks!

Offline fphil

  • Sr. Member
  • ****
  • Posts: 395
  • BHP: 6
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #4 on: March 18, 2014, 11:06:54 pm »
This is my question also.  Perhaps a bit more info into how VEMS uses the deadtime values would really help also.
Have you seen Dave's answer in
http://www.vemssupport.com/forum/index.php/topic,2194.0.html.

Gunni, thanks for the tip. Let's have an automatic tool for that in the wish list!

Offline UrSobsessed

  • Jr. Member
  • **
  • Posts: 30
  • BHP: 0
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #5 on: April 11, 2014, 03:44:42 am »
This is my question also.  Perhaps a bit more info into how VEMS uses the deadtime values would really help also.
Have you seen Dave's answer in
http://www.vemssupport.com/forum/index.php/topic,2194.0.html.

Gunni, thanks for the tip. Let's have an automatic tool for that in the wish list!

I did not.  Thanks for showing me! 

I do still wonder how to create a slope for all of the simplified values using the lambda to figure out deadtime values posted above by Gunni...

Offline fphil

  • Sr. Member
  • ****
  • Posts: 395
  • BHP: 6
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #6 on: April 13, 2014, 12:49:15 pm »
If the injectors had no dead time, the PW would be proportional to lambda (L).
From what I had understood, for some (MAP, RPM), have 2 VE values to get (PW1,L1) and (PW2,L2). Then draw the line trough this 2 points. When that line cross L=0, you get the dead time.
This is a bit theoretical, since this is done for one (MAP,RPM), you should have to take the mean, take care of Voltage, the chosen VE values.
Better to make an Excel sheet or other.

Offline VEMS

  • Administrator
  • Sr. Member
  • *****
  • Posts: 487
  • BHP: 22
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #7 on: April 13, 2015, 06:09:50 pm »
added Gunni's deadtime simple setup procedure to help: http://vems.hu/vt/help/v3/v3_injector_settings.html

Best regards, Dave

Offline darzamat

  • Jr. Member
  • **
  • Posts: 22
  • BHP: 1
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #8 on: October 13, 2015, 02:50:34 pm »
in this calibration process , EGO needs to be off right ?

Offline gunni

  • Hero Member
  • *****
  • Posts: 1464
  • BHP: 36
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #9 on: October 13, 2015, 07:45:38 pm »
Yes. EGO correction could be added but this is quick and simple enough not to require ECO control

Offline darzamat

  • Jr. Member
  • **
  • Posts: 22
  • BHP: 1
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #10 on: October 13, 2015, 09:07:52 pm »
also , is this process is eligible for simplified injector dead time table or just for traditional ?

Offline Manick

  • Jr. Member
  • **
  • Posts: 38
  • BHP: 2
    • Trionic tuning forum, hosted by yours truly!
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #11 on: December 23, 2015, 06:38:04 pm »
I have found the dead times specified for my injectors but im not really sure of what value to use. Deadtimes are specified @ specific voltage, whats best to use for VEMS where i only can enter one?

Precision 1200cc low ohm injectors.

Volts: 8.7v 10.4v 12.2v 13.9v 15.6v 17.4v 19.1v 20.9v
MS: 1.63 1.00 0.80 0.70 0.60 0.56 0.56 0.53
To boost, or not to boost!
Yea i know i have a lot of questions, sorry.. :)

Offline gunni

  • Hero Member
  • *****
  • Posts: 1464
  • BHP: 36
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #12 on: December 23, 2015, 07:40:00 pm »
There is actually another method, in injector settings change it from traditional to simplified.
then you can input your dead times

Offline Manick

  • Jr. Member
  • **
  • Posts: 38
  • BHP: 2
    • Trionic tuning forum, hosted by yours truly!
Re: Setting your injector dead time (Injector voltage compensation)
« Reply #13 on: December 23, 2015, 08:16:43 pm »
Ohhh, awesome! Thanks! :D
To boost, or not to boost!
Yea i know i have a lot of questions, sorry.. :)