Not true, My Sonata has rear disc brakes, but the parking brake has shoes
inside of a drum. I've tried stopping the car with it and doubt it would
have a lot of effect at full throttle.
OTOH, it does have a throttle over ride if you stop on the brakes. Engine
goes to idle no matter the pedal position.
I once owned a couple of Renault 10 shoe boxes, 1730 pounds of
screaming 4 cylinder terror. The cars had 4 wheel disk brakes
and the "emergency brake" was a cable operated cam mechanism
that squeezed the rear calipers. It was a true emergency brake
as opposed to a "parking brake". Those were the weirdest most
fun vehicles I ever owned except for the Renault 16.
On Mar 3, 7:18 am, email@example.com (Doug Miller) wrote:
Gee, I guess it isn't that bizarre then. Yeah, I over generalized
suggesting it applied to all cars, but you were equally wrong
suggesting that it's bizarre to find a manufacturer that designs them
While there may be some sort of unsolved interface problem that causes
an unexpected acceleration one does wonder how many genuine instances
there are? And maybe how many litigiuos one!
There may be also be something to the allegation 'Here's chance to
take a bite out a none North American auto producer'.
But how many 'incidents' are due to driver error or insufficient
competency in dealing with something unusual.
Every driver SHOULD, although one doubts whether many do, know what to
do if/when their vehicle acts in an unexpected manner.
For example when we started towing a trailer with a 1976 Chev. Impala
we reviewed what could happen if, for example we lost the car's power
assisted hydraulic brakes (no dual braking then!) and/or the engine
stopped and we had no power assisted brakes or steering. With engine
off we then practiced bringing the whole rig to a stop by using the
foot operated parking brake. Never had to do it for real but knew we
could and with the family and all gear on board.
In another instance we had a V.W diesel 'take off' (running on it's
own crankcase fumes on a warm day). Having read about the probable
cause we depressed the clutch, disconnecting the engine which started
to race uncontrollably; pulled into side of the road, stopped, and
then stalled the engine, hoping not break anything! It stopped and
when the engine had cooled bit we drove to the dealer.
Many years before, in 1953/4 we had a wheel break off the rear axle of
a 1926 Daimler! But again somehow we knew which way to turn the wheels
and brake (manual rod brakes no power assist at all) to bring the
vehicle to a halt without turning over.
Included in the above axiom of "Think about what COULD happen and
rehearse what to do about it", is that all members of this family
(except one) prefer manual vehicles and state a preference for a
proper hand brake lever located centre console. Which also means that
in certain emergency situations the front seat passenger could also
operate the handbrake!
How do you explain the fact that over the last 5 years or so Toyota
has a rate of these incidents happening that is 2X or 3X the rate of
other car manufacturers? If it was just people doing something
wrong, the rates should be about the same. They are not. I saw a
chart comparing them and GM was low, at like 1/3 the number of
Totyota. And Toyota was similar to other manufacturers before they
moved to the new fly by wire system. Which is not to say that proves
it's an electronic problem, it could be something mechanical in the
design too, but it does tend to support that it's an electronic
The thing that really stood out to me was the statement by Toyota's president
that they're going to look into programming a brake override for the throttle.
I have only one question: WHY IN GOD'S NAME WAS THAT NOT THERE FROM THE
firstname.lastname@example.org (Doug Miller) wrote in
If one's foot is on the brake,the throttle should naturally go back to
although,it would cause some trouble for left-foot brakers when they
unknowingly ride the brakes.
Hmm,might teach them to properly brake,with the right foot. B-)
On Mar 2, 9:48 am, email@example.com (Doug Miller) wrote:
Very good question and apparently one of the key differences between
Toyota and the other manufacturers that do have it. Another
question is if the design other manufacturers used involves the
computer doing it or if there is some seperate circuit that does it.
The obvious problem being that if the computer is the interlock
mechanism, then when it's going nuts and ordering full power, it may
also be incapable of executing the safety program as well.
*Programming* a throttle override by the brake? As in relying on lack
of electronic malfunction in order to have the brake reliably apply an
override onto the throttle?
- Don Klipstein ( firstname.lastname@example.org)
Since the override becomes necessary only in the event of a throttle
malfunction, for the override to not work would require a second malfunction.
Clearly two simultaneous malfunctions are *far* less likely than any single
For additional safety, a mechanical interlock could be constructed -- but the
electronic systems are more reliable.
email@example.com (Doug Miller) wrote in
Doug Miller wrote:
under normal conditions,the operator would/should not be applying both
throttle and brake at the same time.
However,I question any need or benefit for throttle-by-wire(TBW) in an
the old mechanical throttle cable and throttle position sensor at the
butterfly works fine,and has less chance for malfunction,particularly on
newer vehicles.In fact,TBW is added complexity and cost,and more prone to
It violates the KISS principle,too.
As has been demonstrated by the Toyota SW problem,TBW can suffer
programming errors,SW glitches,or component malfunctions resulting in loss
of control of the vehicle.And there's no backup or redundant system as
there are in aircraft.A critical failure and your engine runs away.
after checking Wiki,I found these "benefits" for TBW;
"The significance of ETC is that it much easier to integrate features to
the vehicle such as cruise control, traction control, stability control,
and precrash systems and others that require torque management, since the
throttle can be moved irrespective of the position of the driver's
IMO,if you need a computer to control your traction or vehicle
stability,you should not be driving. If your vehicle needs "stability
control",it's an inherently unsafe vehicle,and should not be on public
You are ASSuming there is a code problem (software). No evidence to
support that assumption at this point. And GENERALLY, solid state and
particularly digital electronics is far less likely to cause problems
than mechanical controls.
No, not necessarily. It is a case of what everybody wants and thinks
is necessary for safety.
ABS is a crock - yet everyone thinks all cars should have it.
Traction control makes it possible to drive in slippery conditions
with the ridiculous wide tires everyone seems to want on their cars.
Same with Stability control.
Better to just put the proper tires on the car and be done with it.
On Mar 2, 9:01 pm, firstname.lastname@example.org (Doug Miller) wrote:
That's obviously totally false. Let's say I have a single computer
that is running the throttle, the shift interlock, and the engine shut
off via the start/stop button. Actually that doesn't sound that far
fetched. Clearly you could write a program in such a way that the
program under certain conditions goes into a program loop where it
will no longer respond to either a change in throttle input or the
stop button and will also not unlock the shift. That's a single
program failure, not two simultaneous malfunctions.
I think it's arguable which are more reliable and which can be
designed to better fail safely. However for it to do what it needs
to do the interlock needs to be totally seperate from the computer
commanding the throttle.
On Mar 3, 10:54 am, email@example.com (Doug Miller) wrote:
That's false too. The probability of two events occuring in
combination is only less IF THE TWO ARE INDEPENDENT. You are arguing
that it's perfectly fine to have the same computer that is running the
throttle to also be the safety override and to disengage the throttle
if the brakes are applied. Running on the same computer, those two
events are no longer independent. Surely you must know that you
could easily design a computer that controlled both where if the
computer ran amock, it could command full throttle and ignore the
start/stop button that is telling it to shut off the engine. I'm
amazed you would argue such a thing. Let's say you have a Microsoft
Word program and Windows Explorer. Are you going to tell us that the
probability of Word hanging and Explorer hanging at the same time and
to stop responding are independent events? That would be true only
if they were running on SEPERATE computers.
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