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Data Analysis challenge
liam.mccaffrey - 13/5/11 at 10:58 AM

I sub to Racecar Engineering Mag and every month they run an article on data aquisition where they have a feature on interpreting telemetry. I must say I really enjoy this and really look forward to it.

This is the one from the current issue, I reckon I have it sussed out but just wanted to share with you guys and see what you thought and whether you enjoyed it as much as I did.

The traces are as follow:-
RPM
Speed
Throttle angle
Throttle pot Voltage
Throttle pedal % depression


Description
Description

[Edited on 13/5/11 by liam.mccaffrey]

Agriv8 - 13/5/11 at 11:12 AM

Throttle pot not calibrated/setup correctly or picking up interferance .

How from - the Spkes on :-
Throttle angle
Throttle pot Voltage

and nothing on :-
Throttle pedal % depression

It hard to tell on there but from the diagrame is the Throtle Pot showing 100 % open ? which it should be at full Chat thus down on power.

Regards

agriv8

TMC - 13/5/11 at 11:34 AM

Cant really see the scale figures on the left of the graph, but it seems that 100% throttle pedal depression is not equating to 100% throttle opening at the business end.

If the car is fitted with a pedal stop then it needs to be moved and better set up, if its drive-by-wire then it needs better calibration.

liam.mccaffrey - 13/5/11 at 11:41 AM

I have the benefit of a clear pic in the magazine, so I'll add a piece of information. The buz on the flat part of the throttle angle trace oscillates between 75 deg and 90 deg.

TMC - 13/5/11 at 11:43 AM

quote:
Originally posted by liam.mccaffrey
I have the benefit of a clear pic in the magazine, so I'll add a piece of information. The buz on the flat part of the throttle angle trace oscillates between 75 deg and 90 deg.


In which case I'm definitely going with my diagnosis: Throttle pedal movement isnt translating to throttle angle correctly.

bigruss - 13/5/11 at 11:50 AM

quote:

Throttle pedal movement isnt translating to throttle angle correctly.


That was my answer too.

MikeCapon - 13/5/11 at 12:33 PM

Bumpy track, poor seating + pedal position = lifting off???????

Agriv8 - 13/5/11 at 12:56 PM

quote:
Originally posted by liam.mccaffrey
I have the benefit of a clear pic in the magazine, so I'll add a piece of information. The buz on the flat part of the throttle angle trace oscillates between 75 deg and 90 deg.



If it alwayd 75 - 90 possible Throttle pot not attached correctly and rotating missreading could also account for spikes at the other end

regards

Agriv8

sebastiaan - 13/5/11 at 03:57 PM

Gearing's too tall.

Paul (Notts) - 13/5/11 at 05:27 PM

With the pedal fully down -100% the throttle is only opening 82.5% BUT engine vibrations pull on the cable and produce a spike from 75 % to 90% as the engine vibrates from side to side.



Paul

Liam - 13/5/11 at 07:03 PM

I'm thinking the spikes on throttle angle/pot that aren't seen on the throttle pedal are automatic throttle blips from the management system for downshifts, so this could be drive-by-wire. The fact the throttle is not fully opening and seems to be fluttering would explain the lack of speed, but not sure what the reason for that would be - mechanical play somewhere or an electrical problem. The fact that the flutter is on the throttle angle trace but not the throttle pot trace may be the key, but I'm not 100% sure what those traces are exactly. I.e. surely the throttle angle must be measured by a pot. If so what is the throttle pot trace? Another throttle pot? Hmmmmmm.

Anyway - 1,000,000 points if I'm right about the auto throttle blips thing, please!

MakeEverything - 13/5/11 at 09:36 PM

My guess is a poor linkage between the throttle pedal and body, a bad earth or voltage loss, or a problem with the butterfly.

MikeCapon - 16/5/11 at 07:48 AM

Well come on then Liam....

What's the answer please?