Dangerous software glitches in Prius hybrids?

Well I have certainly used the handbrake in an emergency when the foot brake on a 2 tonne, 1950's UK car which we'd been restoring failed coming up to traffic lights. Good thing the handbrake was on a long lever 'cause I needed to pull it very hard. :oops:

Wow, scary! I stand corrected!
I assume you were more careful in your restorations after that :) Is this why your cars now are quite lightweight?

CC
 
Such as? With an automatic transmission I don't see too many options...

Many automatics also have an L1 and L2 setting which will engage lower gears and help slow down the car. Also while not good for the tires, putting into neutral and rubbing the curb can help. If there's no obstructions, pull the car onto grass/shrubbery can eventually slow it down.

But yes in general, at least when I was taking driving lessons a few decades ago, we were taught to use the "hand brake" in emergencies, thus why it's also called an emergency brake.

Likewise "hand brake" isn't an entirely good way to describe it, as in many older cars the emergency brake wasn't used by hand at all. It was another foot pedal generally off to in the left hand side of the foot well.

Thus, "emergency brake" is a far more universal term for what people call the "hand brake."

Regards,
SB
 
Many automatics also have an L1 and L2 setting which will engage lower gears and help slow down the car. Also while not good for the tires, putting into neutral and rubbing the curb can help. If there's no obstructions, pull the car onto grass/shrubbery can eventually slow it down.

Ah yes, matter of fact I don't recall seeing an automatic that didn't have those settings.

Likewise "hand brake" isn't an entirely good way to describe it, as in many older cars the emergency brake wasn't used by hand at all. It was another foot pedal generally off to in the left hand side of the foot well.

Thus, "emergency brake" is a far more universal term for what people call the "hand brake."

It's a foot pedal on my 1993 Silverado, which is a better place for it IMO given most people only use it as a parking brake (at least I don't know anyone who uses it for anything else) and it's way easier to push down with your foot than pull up with your arm.
 
Maybe it was a Prius model that has the auto-parking feature? That would make a lot more sense, whether it is user error or a programmer error.

I've never heard of something like this over here though.

Hmm, from what it sounds like after reading the article in detail, it could be a bug where the engine revs up to charge the battery, but then connects to the front axle anyway by accident, so that the engine that's supposed to only spin to charge the battery also accellerates the car. I could see how that's pretty scary, and I have no idea how you could overrule it - if it's a proper bug, then I doubt putting the engine in neutral or a different gear would have any effect at that point. Maybe by pressing the SEV button (drive electronic only, but if you accellerate above 50km/h that turns itself off automatically). That's not available on the U.S. Prius iirc - perhaps the two are related?

Or maybe just pressing the power-off button? Don't know if you can do that while the car is still moving.

The problem with snow mentioned is more well-known, I think, in that the traction control kicks in if you spin the wheels, so if you lost grip sideways while still accellerating, if the traction control kicks in at that point you'll see yourself slide out of the corner much faster (and in a straighter line) than if the wheels were still spinning.

I wouldn't rule out mechanical failure though ... if the cause is that the recharging of the battery by the gas-engine is accellerating the car, I'd reckon the flywheel or whatever is being used to connect and disconnect the drivetrain doesn't disconnect properly anymore.
 
User error more likely. Remember when Audi's would accelerate wildly when the brake pedal was pushed hard during the 80s? Not one case was ever documented or proven, but Audi renamed the cars and moved the brake pedal further to the left for fat American feet. There's no car motor/engine on the planet that can overcome its mechanical brake (emergency brake) let alone the hydraulic one.

That is silly Mize.

The number of people I know who have driven off with their emergency brake engaged is quite large. Engines can easily over come an emergency brake. The hydraulic brakes are another matter. And I agree with the user error comment until further information comes to light.

edit: Sorry I see that horse was severely beaten already.
BTW my drivers ed teacher said he put a coat hangar into the e-brake release for one of those foot ones so he could actually use it in an emergency instead of just have it on/off. That seemed a bit overkill to me. I mean if you have to use it, use it all the way. Still a handle lever one is much nicer for having fun with even if you dont have a FWD. I remember when I practiced sliding into a parallel parking spot with the E-brake it was entertaining and it allows you to go slower in your stupidity.
 
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Maybe it was a Prius model that has the auto-parking feature? That would make a lot more sense, whether it is user error or a programmer error.
I was under the impression that the self-parking feature is brand new for the 2010 model (at least in this hemisphere... don't know about whether they have it already in Japan/EU/AU). The article seems to be talking entirely about examples involving 2nd-gen Priuses (Prii?)
 
Are all of you too young to remember using the parking brake to spin/smoke your rear tires before launching a drag race? Whether or not today's parking brakes are as good as a 67 Mustang, the hydrolic brakes certainly will overcome any motor and then there's that old "off" thing.
 
There's no car motor/engine on the planet that can overcome its mechanical brake (emergency brake) let alone the hydraulic one.

The emergency brake be overcome. When I was selling my old 95 Saturn SL2 the buyer accidently left the emergency brake engaged and starting driving. After getting down the street he commented about the lack of power. I noticed the brake was on. Boy was there a lot of smoke!!!! After it was released he liked the car better. This car had 124 hp, and over 130k miles on it. So it doesn't a lot of hp to overpower the emergency brake.

Jim
 
Many automatics also have an L1 and L2 setting which will engage lower gears and help slow down the car. Also while not good for the tires, putting into neutral and rubbing the curb can help. If there's no obstructions, pull the car onto grass/shrubbery can eventually slow it down.

But yes in general, at least when I was taking driving lessons a few decades ago, we were taught to use the "hand brake" in emergencies, thus why it's also called an emergency brake.

Likewise "hand brake" isn't an entirely good way to describe it, as in many older cars the emergency brake wasn't used by hand at all. It was another foot pedal generally off to in the left hand side of the foot well.

Thus, "emergency brake" is a far more universal term for what people call the "hand brake."

Regards,
SB


Interesting, I had never heard of a foot pedal based one before. I guess it is only done that way on automatics?

CC
 
The auto-parking is available over here at least and has been since 2005 I think, or maybe even from launch (2004 iirc).

That's kind of ironic Cap'n, as the Prius also has a foot pedal for the 'hand-brake'. ;) Most well known for foot pedals currently are Mercedes, I think. Automatics normally hardly ever even need one for parking, as they don't generally move very easily by themselves when in Parking mode!
 
There's no car motor/engine on the planet that can overcome its mechanical brake (emergency brake) let alone the hydraulic one.

Um.. Are mechanical brake\ emergency brake the same thing as parkingbrake\handbrake?

I have driven around with the hand brake on in my merc for short periods several times by accident. I didn't notice anything except for the dash starting to blink red and telling my i was doing something stupid. The car pulled pretty much as good as it allways pulls.

I dont think these brakes are very powerful, nor do you need a lot of hp tourque. 90% of the time i did this in the merc, i was backing out of parking lots..

Hell, even our old S70 volvo would overcome the handbrake.

A m8 of mine "borrowed" his moms Ford Focus when we where 15-16 (you need to be 18 to get a driving licence in norway) and we drove like 2-3km with the emergency brake on. That focus probably didn't have more than 100hp... We didn't really notice anything (except that the car was rather slow)
 
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Still a handle lever one is much nicer for having fun with even if you dont have a FWD. I remember when I practiced sliding into a parallel parking spot with the E-brake it was entertaining and it allows you to go slower in your stupidity.

Whats the point of using your e-brake unless your driving a FWD?

Using e-brake to slide an RWD car would just be stupid. Just learn how to drive a RWD properly, and you can easily control oversteer by throttle control. Safer, faster, funnier, everything.

Using an e-brake to slide is just dangerous, completely locks your wheels. Just using physics to your advantage is much more rewarding and a 100 times safer
 
I would say that the emergency brake that was referred to is the mechanical brake that engages for a fully pressed brake pedal. This acts as a backup system in case the hydralic braking fails, and can deliver full brake power to the wheels.

And unless the car designers are completely stupidm brake power should always be greater than available engine torque.

/humbert
 
I have driven around with the hand brake on in my merc for short periods several times by accident. I didn't notice anything except ....
What? You didn't notice a hot/burning smell?

As for the engine overcoming the handbrake, it's "trivial" in our Renault Scenic. You just drive off and the handbrake releases automatically. It took some getting used to at first but I quite like it now.
 
Whats the point of using your e-brake unless your driving a FWD?
For that matter, using the e-brake isn't 100% necessary to get a slide even on FWD. Usually involves something that makes the rear slide more easily than the front, which can include some suspension tuning, some braking bias, and/or simply lower tire pressure in the rear than the front. It would also typically involve some hard left-foot braking and disabling any existing ABS.

The rear also breaks easily on some FWD cars simply because they have such an extreme forward weight bias that with some basic weight shifting from a strong feint, you could almost lose rear traction just from the weight shift.
 
(I accidentally posted this in an edited post on the previous page earlier today)


Hmm, from what it sounds like after reading the article in detail, it could be a bug where the engine revs up to charge the battery, but then connects to the front axle anyway by accident, so that the engine that's supposed to only spin to charge the battery also accellerates the car. I could see how that's pretty scary, and I have no idea how you could overrule it - if it's a proper bug, then I doubt putting the engine in neutral or a different gear would have any effect at that point. Maybe by pressing the SEV button (drive electronic only, but if you accellerate above 50km/h that turns itself off automatically). That's not available on the U.S. Prius iirc - perhaps the two are related?

Or maybe just pressing the power-off button? Don't know if you can do that while the car is still moving.

The problem with snow mentioned is more well-known, I think, in that the traction control kicks in if you spin the wheels, so if you lost grip sideways while still accellerating, if the traction control kicks in at that point you'll see yourself slide out of the corner much faster (and in a straighter line) than if the wheels were still spinning.

I wouldn't rule out mechanical failure though ... if the cause is that the recharging of the battery by the gas-engine is accellerating the car, I'd reckon the flywheel or whatever is being used to connect and disconnect the drivetrain doesn't disconnect properly anymore.
 
Okay guys, enough with the emergency brake follow-ups. No a two-wheel mechanical brake won't stop most cars with full throttle engaged, but foot-hydrolics will
 
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