Unintended Acceleration...

[LM]

They were so panicked by Californica smog standards that they wanted

the ignition to simply die if the sensor was lost.



I refused to be a party to such a fiasco, arguing someone could die if

the engine quit at just the wrong moment, and suggested the "limp

home" method. When they realized I'd simply bow out and rat ("whistle

blow" in modern lingo on the whole scheme they agreed with me.

Could you do something similar to the EU politicians, they are certified idiots.

 

[Lasse Langwadt Christensen]

Den torsdag den 31. oktober 2013 23.55.07 UTC+1 skrev Don Y:

Hi Paul,

Don Y wrote:
[%X---stuff on Toyota Unintended acceleration event -- %X]

I've gone through a similar exercise with "theft prevention" in mind
(aftermarket being far preferable to factory installed as it would
be less ubiquitous -- less likely to be a "known" to a would-be thief),

In your specific case, "neutral" is your friend! :>

Absolutely.

It always amazes me how easily people seem to panic/lose all

sense of reason in these situations! :-(

I have had cars with mechanical failures of the clutch, throttle linkage and

accelerator pedal springs at various times. Even one with a gear-box that

decided to be extremely random about which gear it would let you have. All

still limped home for remedial work OK. All of the recovery actions that

should be common sense to all drivers (sadly it does not seem to be) always

worked well enough for me. This was, however, before the ECU became an

addition to the vehicles. Only had a failed hydraulic clutch system since

then and still managed to get that home as well.

I once lost a wheel bearing in one of the front rotors (disintegrated).

The wobble in the rotor was enough to forcibly drive the calipers

apart rendering the hydraulics useless.

haven't a dual diagonal brake system been mandatory since for ever ?

-Lasse

 

[Lasse Langwadt Christensen]

Den torsdag den 31. oktober 2013 23.05.16 UTC+1 skrev John Larkin:

Seems like a parts-per-billion risk. You'd waste hours of your life

for, likely, seconds of probable return.



And, if you don't panic, can't you just shift into neutral?

would be the obvious solution, the engine would stutter at the revlimiter
and not much more

and I don't think there's a car where the brakes cannot over power the
engine

look at the statistics
http://en.wikipedia.org/wiki/List_of_motor_vehicle_deaths_in_U.S._by_year

it's not like it started going up after computer were invented

-Lasse

 

[Don Y]

Hi Lasse,

haven't a dual diagonal brake system been mandatory since for ever ?

No. Traditionally, rear wheel drive vehicles had front disc
and rear drum brakes. This system is split front vs. rear
(instead of diagonally as in all disc).

The wobble in the front wheel (rotor) forced the calipers so far apart
that the front hydraulics were effectively inoperative (though no
"leaks"). As such, only the cylinder for the rear axle was operative.

Front brakes do *most* of the stopping in a car. Having to resort to
just the rear *drums* leaves you with severely compromised braking.
Esp for a "full size" car (i.e., what *used* to be called "full size"...
not the midget mobiles they call full size nowadays!) traveling at a
high rate of speed.

With the parking brake link missing on one side, that side had
effectively no stopping power and the other side had reduced
capability due to the added slack in the cable.

 

[Nico Coesel]

With all the revelations coming out of the Toyota unintended acceleration
trials, it's got me thinking about how fewer and fewer "ignition switches"
directly control the engine. More and more we see drive by wire and ignition
switches that are simply logic inputs to the Engine Control Unit (ECU). ECU
goes haywire and all bets are off.

Just put your foot on the brake and the gear in neutral to stop the
car. Some people panic and press the accellerator.

It has never been proven or reproduced (not even by NASA who conducted
the first investigations!) that the cars accellerated by themselves.

 

[Nico Coesel]

The rationale was that power to the ECU might be supplied by several
circuits plus any possible parasitic power sources that may keep it
energized. Too much possible interaction that will vary from one vehicle's
implementation to another. Working here on the KISS principle. Interrupting
the fuel source seems reasonable.

Very bad idea. What if that happens when you are on railroad crossing?
Or on a bridge which is about to open? Or when you are overtaking a
car with a truck coming up from the opposite direction?

 

[Greegor]

Somebody commenting on the EDN article
mentioned the Therac-25 catastrophies.

VERY interesting reading.

http://users.csc.calpoly.edu/~jdalbey/SWE/Papers/THERAC25.html

 

[josephkk]

Very bad idea. What if that happens when you are on railroad crossing?
Or on a bridge which is about to open? Or when you are overtaking a
car with a truck coming up from the opposite direction?

Excuse the question, but just how does engine reduction eliminate the use
of steering and breaking? Nothing will help willful driver stupidity.

?-)

 

[josephkk]

would be the obvious solution, the engine would stutter at the revlimiter
and not much more

Maybe, if it was implemented correctly.

and I don't think there's a car where the brakes cannot over power the
engine

I have owned two different makes where they couldn't (in first or second
gear).

 

[Martin Brown]

Maybe, if it was implemented correctly.

Removing power from the road wheels is the least worst option.

I have owned two different makes where they couldn't (in first or second
gear).

There aren't many. Brakes usually beat any engine in a high gear
provided that you use them properly. Allow them to get mad hot by misuse
going down a hill and then brake fade becomes a problem.

But in locked first or second gear they aren't likely to be going at
very high speeds where a collision will mean certain death. Car and
driver seem to think that most of these UA events in the US are due to
people who cannot distinguish between the brake and gas pedals!

http://www.caranddriver.com/feature...toyotas-unintended-acceleration-scare-feature

The same applies to the Audi scare many years earlier. I am not
impressed with the Toyota firmware faults as described in EDN

http://www.edn.com/design/automotiv...ler-firmware--Bad-design-and-its-consequences

The think I don't understand is that heavy application of the brake
pedal should always countermand throttle cruise control.

No but the road death rates are already much higher than in other
countries. Countries like Belgium and Italy have similar driver fatality
rates. Depending on the metric you use driving in the USA is between 2
and 4 times more dangerous than driving (faster) in the UK.

http://en.wikipedia.org/wiki/List_of_countries_by_traffic-related_death_rate

Belgium is broadly comparable and they have the insane priorite a droite
rule still applied to about half their road junctions. That is a car can
fly out of a side road and have priority over a fast car on the major
road provided that they do not slow down! Needless to say the resulting
accidents almost always injure the brave Belgian driver.

 

[Spehro Pefhany]

On Fri, 1 Nov 2013 03:22:07 -0700 (PDT), the renowned

I had the pleasure of driving a rental Prius. Not only did it have no actual ignition switch, but it had no shifter either - there was a joystick with digital display to allow you to select drive, reverse, park, or 'engine braking' setting.

If that thing had decided to take off, nobody could do anything about it.

It gives me the willies when I see industrial robotics at trade shows
where they enclose the robot's programmed range of motion in a lexan
cage (to keep the people away). If the robot (by programming mistake
or otherwise) were to fully extend and take a swing it could easily
smash the shell and kill a few people.


Best regards,
Spehro Pefhany

 

[Tauno Voipio]

I had the pleasure of driving a rental Prius. Not only did it have no actual ignition switch, but it had no shifter either - there was a joystick with digital display to allow you to select drive, reverse, park, or 'engine braking' setting.

If that thing had decided to take off, nobody could do anything about it.

There are clear instructions in the manual (600+ pages) what
to do in case of a runaway throttle (which I think was really
an user error).

We have 3 Toyota hybrids in the family, with no problems at all.

 

[George Herold]

I'm certainly certifiable... not sure of which categories... though
I've been a certifiable asshole since early Motorola days >:-}

Chuckle, Glad to hear you don't take yourself too seriously.
(on a personal note I've been a certifiable jerk to my 'better half', but my head seems to be 'on straight' now. Thanks goodness women seem to have an infinite supply of forgiveness.)

George H.

 

[Oppie]

My attitude as well.

Don't forget how many of the automatic transmissions are electronically
shifted by the powertrain control module. You might feel a nice detent when
you shift but that is just moving a selector switch on the PCM. Just how
fail-safe that is, I can't say.

 

[Oppie]

Does the transmission selection go through the computer on some of these
vehicles?

As previously written, yes. The PCM controls solenoid valves and
electronically shifts the transmission. It's essentially shift by wire.

 

[stratus46]

NASA from what I understand, got all their information from what Toyota

chose to furnish. In the Oklahoma trial, expert witnesses actually got

source code to analyze.

http://www.edn.com/design/automotiv...d-its-consequences?elq=8bcc20a4112a4dfa967142

852fed7c13&elqCampaignId=2082

http://www.eetimes.com/document.asp...,10201647359779944&fb_action_types=og.likes&f

b_source=other_multiline&action_object_map={%2210201648823856545%22%3A223060667870311%2C%2210201647359779944%22%3A55943103079500

4}&action_type_map={%2210201648823856545%22%3A%22og.likes%22%2C%2210201647359779944%22%3A%22og.likes%22}&action_ref_map=[]

OK, I even have a pdf, and I gave a link to it here last year, of an internal report

that describes the bug, google

toyotamemoenglishtranslation1.pdf



I have just read these links you gave, and indeed from Barr's POV it is crap.

But we must not forget ECC RAM and stuff like that is not that common in embedded systems.

It must be clear to anyone that 'electronics' will not make a car safer (than simple mechanics).

In airplanes you may have 3 the same systems and an arbiter so to speak, if any system disagrees...

majority vote, but even then, no 100% guarantee.

If Mr Barr looked at my latest code he would probably die drowning in tears, my PICs have only limited stack space,

and lack some of the features he considers necessary...



Where is the limit?

I do not want to justify Toyota, neither the F*ckupshima nuclear plant design, but hey, life goes on.

Buy an old Mercedes diesel and you are OK...



If it is anyway like the environment I used to work in, then there is anincredible time pressure

to get things working, not sure how many man hours Barr spend testing allthat stuff, but think about it.



We can learn from Mr Barr's report though, I often worry about stack depth.

But really and honestly, I would drive a car that was controlled by a controller I designed without all those features Barr says it 'needs'.

Something is up to the driver too.

For sure cars should not start accelerating by themselves, and coffee should not bee too hot.

(Mc Donalds lawsuit, milions?) But would a decent driver not know a few tricks how to stop it?

I have driven cars that .. well you do not want to know.

US lawsuits... come to think of it : Should not have NSA been listening to the controller?

Now you get internet, maybe remote software updates by the factory while you are driving?

Do you think things will get better?

LOL

What you say is true but when the fit hits the shan, even the best driver might do things that are bad.

They told us that 'pumping the brakes' will help you regain control during a skid but when you're IN that skid, one half of your brain says pump the brakes but the other half says STOP NOW and to hell with pumping brakes. Theother half often 'wins' the debate which is why ABS is helpful. The computer just monitors wheel motion and helps without the panic of people.

G²

 

[Spehro Pefhany]

ABS and things are a big help, or at least can be.

If the power steering goes, you're gonna need those abs.


Best regards,
Spehro Pefhany