NefMoto

Technical => Tuning => Topic started by: RBPE on May 01, 2017, 05:55:42 PM



Title: Sudden acceleration
Post by: RBPE on May 01, 2017, 05:55:42 PM
Some interesting info on sudden acceleration in electronic systems;

http://www.autosafety.org/dr-ronald-a-belts-sudden-acceleration-papers/

Some Bosch info in there too looking familiar;

(https://c1.staticflickr.com/3/2844/34236176682_1ee77a412b_b.jpg) (https://flic.kr/p/Uakmyj)Torque management (https://flic.kr/p/Uakmyj) by Rick B (https://www.flickr.com/photos/146155164@N03/), on Flickr


Title: Re: Sudden acceleration
Post by: nyet on May 01, 2017, 10:03:33 PM
LOL @ footnote 8

http://www.autosafety.org/wp-content/uploads/import/Simulation%20of%20Sudden%20Acceleration%20in%20a%20Torque-Based%20Electronic%20Throttle%20Controller.pdf


Title: Re: Sudden acceleration
Post by: nyet on May 01, 2017, 10:10:18 PM
This is a really interesting find!

Thanks!


Title: Re: Sudden acceleration
Post by: prj on May 01, 2017, 10:57:16 PM
This is why most cars have LFB disabled from factory and in fact this is not a problem.
Even if you are able to coerce the throttle to open more than it should, stepping on the brake will instantly shut it completely.

And then level 2 monitoring will kill the engine.


Title: Re: Sudden acceleration
Post by: nyet on May 01, 2017, 11:14:54 PM
It seems like a load of crap. I've had all sorts of battery/alternator issues, and never once saw anything like sustained throttle body opening.


Title: Re: Sudden acceleration
Post by: prj on May 02, 2017, 12:03:21 AM
I mean it is possible, but not on a Bosch ECU.
The reason is torque monitoring and level 2 monitoring.

It monitors pedal vs torque. So even if the throttle fails completely and reports utter bs, the pedal value will still be zero and it will just cut out.


Title: Re: Sudden acceleration
Post by: AARDQ on May 02, 2017, 09:36:05 AM
"The answer is that they didn’t do it by pressing on the accelerator pedal. Instead, Mother Nature found a way to make the engine speed increase while the driver’s foot was off the accelerator pedal and without producing any engine torque, so there was no need for the engine torque to overcome the load caused by the drive train.."  (Page 20)

Cool, acceleration with no torque.   :P

The upshot of his theory that the torque controller thinks that the idle controller still has control as a result of 0% pedal (however it ends up in that situation) and does nothing to intervene as a result doesn't seem far-fetched.  

Controllers entering the wrong mode for the circumstances is not an unusual thing at all:  https://en.wikipedia.org/wiki/TAM_Airlines_Flight_3054, or http://ccnr.org/fatal_dose.html  for a particularly chilling example.


Title: Re: Sudden acceleration
Post by: prj on May 02, 2017, 12:01:41 PM
It does not matter, idle or not idle.
Read up how level 2 works.

Too much engine torque with pedal @ zero = throttle control off.

It might be possible on some Jap ECU's or other poor implementations, but this can never happen on Bosch.


Title: Re: Sudden acceleration
Post by: nyet on May 02, 2017, 12:12:01 PM
Quote
Instead, Mother Nature found a way to make the engine speed increase while the driver’s foot was off the accelerator pedal and without producing any engine torque, so there was no need for the engine torque to overcome the load caused by the drive train..

Utter bullshit. There is no way for this to happen unless the pedal itself malfunctions and is sending a >0% signal.

"Mother Nature"?

Please.


Title: Re: Sudden acceleration
Post by: vwaudiguy on May 02, 2017, 02:39:45 PM
I know this is slightly off-topic, but we had a golf R come in once with some very strange issues no other local shop could figure out. After some testing/ inspection, we found half of the throttle butterfly (plastic) was missing. The car idled perfectly. I was impressed at the ability of the ecu to maintain perfect idle with the throttle plate open 50%. I regret not logging ign timing and fuel on that car before we did the repair.