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From: Jamie on 13 Mar 2010 20:24
Paul E. Schoen wrote:

>
> "Jasen Betts" <jasen(a)xnet.co.nz> wrote in message
> news:hnfobv$rtg$1(a)reversiblemaps.ath.cx...
>
>> On 2010-03-11, Bret Cahill <BretCahill(a)peoplepc.com> wrote:
>>
>>>> To me it has the ear marks of a in fuel-accelerator computer system
>>>> problem.
>>>> It's as though the processor goes into la-la land for no apparent
>>>> reason
>>>> into a full, max on failure mode. When the techs look at it, they can't
>>>> replicate the problem. The processor never does it again, at least
>>>> while
>>>> anyone is looking. We've never seen software do that have we? No!
>>>>
>>>> But the real problem is Toyota's secrecy, not allowing any third
>>>> party to
>>>> examine their documentation even to the point of defying court
>>>> orders. They
>>>> have blown smoke up each other's butts with attempted fixes, floor
>>>> mats and
>>>> accelerator mechanical fixes but likely to no avail. Failures keep
>>>> coming
>>>> and Toyota believes their own propaganda. It's time for an independent,
>>>> third party look into the problems including Toyota's engineering and
>>>> documentation without a connection to Toyota but with full openness
>>>> on their
>>>> part. Otherwise, maybe we should forbid them from selling in the US
>>>> until
>>>> they are more open.
>>>>
>>>> The San Diego Prius should be impounded by the TSA and examined by
>>>> them just
>>>> as an airplane would be.
>>>
>>>
>>> It's hard to believe that a brake system designed to take the car from
>>> 60 - 0 in 3 seconds cannot prevail against a drive train that can only
>>> put out a fourth that much power.
>>
>>
>> with the throttle wide open the manifold vacuum is not there
>> so there's no power assist on the brakes.
>>
>> if the driver is somewhat feeble it's conceivable that they will not be
>> able to stop the car using the brakes.
>
>
> Also, if the car has ABS, it will be activated by mashing the brake
> pedal. That will prevent any of the wheels from locking up, so it will
> purposely reduce pressure on the brakes. The Prius has an electric motor
> as well as an ICE, and it is more powerful (60kW=80HP) in newer models.
> An ICE would stall if the brakes were locked, and starting torque is
> more limited, but an electric motor has a lot more low end torque. I
> think there are some fairly obvious factors that have been overlooked
> and perhaps some redundant safety features may have been phased out to
> cut costs.
>
> Here is an excerpt from the specs on the 2010 Prius:
> "Star Safety System: Regenerative Anti-Lock Brakes (ABS) with Brake
> Assist (BA), and Electronic Brakeforce Distribution (EBD) Vehicle
> Stability Control (VSC) and Traction control (TRAC)"
> http://pressroom.toyota.com/pr/tms/toyota/document/2010_Prius_Product_Info_FINAL.pdf
>
>
> So some of these safety features may conspire to create an unsafe
> condition. I doubt that engine vacuum is used for the power assist, as
> the ICE is not always running, and much of the motive power is derived
> from the electric motor.
>
> There is also a recall for an ABS software problem:
> http://www.toyota.com/recall/abs.html?srchid=K610_p280864904
>
> The following indicates that the power assist for brakes is electrical.
> It also describes in some technical detail how the ABS, VSC, and EBD
> adjust braking pressure. And there may also be an issue with the
> Regenerative Braking Control. It states that the MG2 is mechanically
> connected to the front wheels and used to provide regenerative braking
> under normal deceleration requests. But it is only a little change of
> motor control software that makes the motor operate as a generator. And
> all of these software systems, AIUI, are activated only by the resistive
> sensors on the throttle and brake pedal position sensors. I don't think
> there is a backup pressure switch or end travel switches to detect
> extreme conditions and activate any sort of mechanical override or
> electrical kill switch.
>
> http://www.autoshop101.com/forms/Hybrid16.pdf
>
> All of these fancy controls are wondeful when working properly, but
> unlike mechanical systems they do not tend to fail gradually and
> gracefully so that problems can be noticed by the driver. Things can get
> dangerous if something goes wrong...goes wrong...goes wong..go on...go
> on...go go go go go!!!
>
> Paul
>
>
well maybe the E-Brake which should be a cable driven device via the
operator should have a kill switch in it..! It solves 2 problems.
Driving with the brake on and being able to kill it incase of runaway..



From: sparky on 13 Mar 2010 22:31
On Mar 10, 10:39 pm, Bret Cahill <BretCah...(a)peoplepc.com> wrote:
> > > Two items - one personal, one only secondhand.
>
> > > 1. My 2008 Tacoma puckup is under the "floormat" recall.  I noticed
> > > the assembly was wrong whe I bought the truck.  The Toyota-provided
> > > overlay mats have grommeted holes for hooks to keep the mats from
> > > moving.  However, the hooks are only installed on the passenger side
> > > of the truck - maybe they thought it was to be right hand drive?
>
> > > 2. A woman my wife works with had a new (2010) Corolla.  She had not
> > > ecperienced any of the litany of problems, but took it in for the
> > > "sudden acceleration fix".  10 days later, her brother was driving the
> > > car and she ws riding with him when the car experienced a sudden
> > > acceleration event.  Her "fix" was successful - she went directly to a
> > > Honda dealer and traded it in on a new Accord.
>
> > > At this point, I don't plan to take my truck in for the "floormat fix"
> > > and the "courtesy" brake override fix (hitting the brakes above 30 MPH
> > > returns the throttle to idle).  I don't believe that Toyota knows
> > > which way is idle in the throttle control unit (bit X or inverted bit
> > > X - which is pretty basic electronics ;-)
>
> > It adds significantly to the seriousness of this problem when people such as
> > yourself tell of experiences such as this. I don't really trust the
> > electronic drive-by-wire systems. The closest thing I have experienced with
> > this sort of problem was with my 1998 Saturn, where sometimes the idle speed
> > would increase from its normal 800 RPM to 1500 or even 2000 RPM. It's a five
> > speed manual, so I only noticed it when I changed gears or held in the
> > clutch or put it in neutral. I think the problem was a bad temperature
> > sender which told the computer that the engine was cold.
>
> > Also, I think the electronic system had only limited control over the
> > accelerator, so it could only affect idle speed by cracking the accelerator
> > perhaps 10%. It used a cable which connected to the air horn, so it could
> > not provide full power position and the brakes probably would overpower the
> > engine. Besides, being a manual transmission, if there was any sign of
> > unintended acceleration, I would have instinctively taken it out of gear.
> > I've always had M/T vehicles since 1970, and I really don't want an
> > automatic.
>
> > It is a bit scary when we allow mechatronic systems to take over things that
> > have previously been performed with manual control, perhaps with a bit of
> > power assist, but always overridable manually.
>
> > My current 1989 Toyota 4WD Pickup is under recall notice for a defective
> > steering relay rod, but I haven't taken it in. I have owned several Toyotas,
> > and I have been fairly well impressed with the quality and lack of major
> > problems. But I had a 1982 Toyota LongBed that had some potentially deadly
> > steering problems.
>
> > Once, when I was pulling out of a parking space, the steering wheel suddenly
> > became very loose. My first thought was that it was on a sheet of ice. But
> > the steering mechanism ball joint had popped out of the socket, which would
> > have been really interesting if I was maneuvering in high speed traffic!
>
> > And not long after that, I had pulled into a snow-covered dirt parking area,
> > and I found I had problems steering, which I assumed was caused by ice. But
> > when I looked, one wheel was pointed in one direction, and the other was
> > pointed elsewhere. A tie rod end had come loose. I was able to pop it back
> > in and secure it with baling wire until I gingerly drove to the shop. But,
> > again, fortunate that I was not going fast. It had almost 200,000 miles on
> > it, and it was probably time for a major steering overhaul.
>
> > I really don't trust electronics to drive my vehicle for me. And I don't
> > need to have it park itself. Imagine if that procedure got called when you
> > were just rolling along on the Interstate with 18-wheelers all around you!
>
> Automation is good as long as there is an override and everyone knows
> how to use it.
>
> NPR SDSU just had some commentator claim that every vehicle including
> every hybrid electric has a neutral.  If you don't know where the
> neutral is you shouldn't be on the road in the first place and ought
> to get a ticket for not knowing how to drive your vehicle.


Almost true !

Except that if the computer is not working a fly by wire vehicle will
not go into neutral since you are giving a command to the computer to
tell the transmission to shift into neutral.

From: Bob Masta on 14 Mar 2010 10:30
On Sat, 13 Mar 2010 20:24:45 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net>
wrote:

>well maybe the E-Brake which should be a cable driven device via the
>operator should have a kill switch in it..! It solves 2 problems.
>Driving with the brake on and being able to kill it incase of runaway..

Can't the user just shut off the ignition key? Or
is that interlocked "as a safety feature" when the
car is moving? Or when in Drive, which might be
interlocked for some reason?

Back in the day (early '70s) when I was a young
engineer at GM's Cadillac division and most cars
still had carburetors, if you shut off the
ignition at expressway speeds while in Drive, the
engine would "windmill" and continue to pull in
air... and fuel, of course, from the carburetor.
But since the ignition was off there was no spark,
so the raw mix went straight to the catalytic
converter where it burned so hot that the
converter melted in a few seconds.

No interlock back then... ahh, the good old days!


Bob Masta

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From: Jamie on 14 Mar 2010 10:37
Bob Masta wrote:
> On Sat, 13 Mar 2010 20:24:45 -0500, Jamie
> <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net>
> wrote:
>
>
>>well maybe the E-Brake which should be a cable driven device via the
>>operator should have a kill switch in it..! It solves 2 problems.
>>Driving with the brake on and being able to kill it incase of runaway..
>
>
> Can't the user just shut off the ignition key? Or
> is that interlocked "as a safety feature" when the
> car is moving? Or when in Drive, which might be
> interlocked for some reason?
>
> Back in the day (early '70s) when I was a young
> engineer at GM's Cadillac division and most cars
> still had carburetors, if you shut off the
> ignition at expressway speeds while in Drive, the
> engine would "windmill" and continue to pull in
> air... and fuel, of course, from the carburetor.
> But since the ignition was off there was no spark,
> so the raw mix went straight to the catalytic
> converter where it burned so hot that the
> converter melted in a few seconds.
>
> No interlock back then... ahh, the good old days!
>
That was fun then, you do that for a short time and turn
the ignition back on! POW!
:)

From: krw on 14 Mar 2010 14:02
On Sun, 14 Mar 2010 14:30:29 GMT, N0Spam(a)daqarta.com (Bob Masta) wrote:

>On Sat, 13 Mar 2010 20:24:45 -0500, Jamie
><jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net>
>wrote:
>
>>well maybe the E-Brake which should be a cable driven device via the
>>operator should have a kill switch in it..! It solves 2 problems.
>>Driving with the brake on and being able to kill it incase of runaway..
>
>Can't the user just shut off the ignition key? Or
>is that interlocked "as a safety feature" when the
>car is moving? Or when in Drive, which might be
>interlocked for some reason?

Yes, it's interlocked. ...to the steering wheel - bad plan.

<...>
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