jecuk
|
| posted on 14/3/06 at 05:01 PM |
|
|
Blackbird ECU - does it output the current gear?
Algorithmic gear calculation is not going well. Does the ECU output a current gear and if so does anyone know where I can pick it up?
|
|
|
|
|
shortie
|
| posted on 14/3/06 at 05:11 PM |
|
|
As far as I know the ECU doesn't output the current gear, gear will normally be calculated by a combination of engine revs and speed IIRR.
What gear indicator have you got?
Rich.
|
|
|
jecuk
|
| posted on 14/3/06 at 05:27 PM |
|
|
It is in a datalogger and the calculation is not going too well so far. Was hoping to cheat and pull the actual gear!
|
|
|
Jon Ison
|
| posted on 14/3/06 at 06:15 PM |
|
|
sorry, no, there is a speed pick up from the gearbox though, are you using this output or your own ?
|
|
|
chriscook
|
| posted on 14/3/06 at 06:34 PM |
|
|
Are you trying to do it live or on recorded data?
|
|
|
jecuk
|
| posted on 14/3/06 at 09:07 PM |
|
|
Jon, I am using the ECU RPM signal. That looks to be working fine. Final drive is about 3 times so I will plug that in and see how I go.
Chris, currently recorded but will be putting in a dash so will need to be real time soon.
|
|
|
chriscook
|
| posted on 14/3/06 at 11:30 PM |
|
|
If your raw data is good this should be pretty easy - however you need to handle the periods when the clutch is slipping or disengaged.
Post up some of your data...
|
|
|
jecuk
|
| posted on 19/3/06 at 10:23 PM |
|
|
I am nearly there and I will post up some of the data. I don't have the car with me at the moment but am doing the following calculation and
assuming standard sprockets.
RPM/gear ratio/primary reduction/final reduction*tyre circumference (m)*60/1000=speed (kph)
Have I screwed it up? The gear trace looks roughly right but you can see the effect of a blip about 1/3 of the way through the lap.
 
Rescued attachment data log.JPG
|
|
|
chriscook
|
| posted on 19/3/06 at 10:57 PM |
|
|
Can't see your timebase on the plot, how long is the 'blip'? Perhaps you could only register a new gear once it has been in that
gear for a short period of time just longer than the clutch is slipping?
|
|
|
jecuk
|
| posted on 20/3/06 at 12:05 AM |
|
|
The blip last for about 1 second. The total lap was 1min 20s.
It is hard to see but it is obviously speed, RPM, Gear on the plot.
[Edited on 20/3/06 by jecuk]
|
|
|
