Any American owners of Toyota Prius out there?

[chrismb]

Can someone tell me if the ignition keys of the Toyota Prius models you have over there are locked once at speed? I can't really understand why we are hearing of these incidents [in the US] where people end up 'unable to stop'. Why not just turn the ignition off?

[EricF]

Can someone tell me if the ignition keys of the Toyota Prius models you have over there are locked once at speed? I can't really understand why we are hearing of these incidents [in the US] where people end up 'unable to stop'. Why not just turn the ignition off?

I think the ones that have the 'unable to stop' problem use a keyless ignition

[blaisepascal]

Can someone tell me if the ignition keys of the Toyota Prius models you have over there are locked once at speed? I can't really understand why we are hearing of these incidents [in the US] where people end up 'unable to stop'. Why not just turn the ignition off?

My understanding (from having friends who are Prius owners, reading about the issue, etc) is that the Prius's aren't experiencing problems with unintended acceleration. Their problem is in certain situations a delay in braking. Those situations seem to be related to the interaction of three different fly-by-wire braking systems (the regenerative braking, the mechanical braking, and the anti-lock braking system), with the end result being when you are trying to slow down suddenly on a low-traction surface your brakes stop working for a fraction of a second.

Newer Toyota models are shipping with keyless entry/ignition systems. Instead of putting the key into a mechanical lock, the key fobs have a proximity sensor and push-button ignition. I've heard that in some of these systems the way to turn the engine off involves holding down the button for 3 seconds.

Frankly, if my car (which uses a key) experienced a period of uncontrolled acceleration, I'm not sure I'd have the piece-of-mind to think about turning the ignition off, even though I know, sitting here in my chair in front of a computer without adrenalin pumping through my blood and a 72bpm heart rate, that shifting to neutral and turning off the ignition are both good ways to stop the acceleration.

[Tom Ligon]

The Prius is a gas/electric hybrid, with some recent versions being plug-in all-electric. These use computer control to determine if the gas engine is even running, and to apply power to the electric drive ... it also has the computer decide if you should use the brakes or regenerate to put power back into the batteries. Evidently it has a "Start" button rather than a conventional ignition switch.

A lot of new cars have security means other than mechanical keys, including some sorts of RF key fob. I surmise this type of vehicle does not use a conventional keyed switch, but some sort of computer control of an electronic switch.

I'm not sure hybrids even have a transmission ... electric drives supposedly don't need them. There may not be a neutral?

Some hybrids and electrics are totally "fly by wire", with no mechanical link between the steering wheel and the front wheels. I ain't buying one.

Bill Gates once cracked about what cars would be like if Microsoft made them (very fast, cheap, etc). GM supposedly countered with this:

http://mistupid.com/jokes/msvgm.htm

The last line is this:

10. You'd have to press the "Start" button to turn the engine off.

So my question is, at what point did the auto industry decide this was NOT a stupid idea? Always provide some positive means of shutting down the car, independent of what a suicidal computer wants to do. Anyone with questions, watch the movie "2001."

[chrismb]

I think the ones that have the 'unable to stop' problem use a keyless ignition

That would explain some of it. I was wondering whether it was something to do with the drivers being American - a country where cars are treated just as "domestic appliances" that occupy little attention from many Amercians. (That's no bad thing, mind - taking away the emotive side of car ownership is good in sooo many ways. I've always applauded the American's sober approach to car use.)

It never occurred to me before this Toyota stuff, but my cheap-and-cheerful run-of-the-mill family Vauxhall Vetra diesel (GM/Opel) cuts the accelerator if you also apply the brakes. It's a nuisance if you're trying to scrape off a bit of rust off the discs, with left-foot-braking, when it's been sitting a while, or wiping them dry after a big puddle, but now I see the sense of it! I mean, how difficult is *that* to implement - cut the accelerator if the brake peddle is depressed?!

Yes, I realised that there is some issue with brake blending (there usually is, it is a difficult algorithm to get right) but there are a couple of reports today of events where both priuses and Lexus' have stuck accelerators.

I had a mid-80's Citroen model with one of the first mass-produced electronic ABS systems and one of the problems with ABS is that if you're on a bumpy road then ABS has a tough time because it might lock up an axle whilst it is 'bouncing' over a bump, then think the car has stopped but instead skid, quite contrary to ABS intent. So in this Citroen system, the ABS just used to come on full time if you ever braked and the road was bumpy. Just 'on', and that was that, you got it whether you wanted it or not! I suppose that was a pragmatic, but inefficient solution. I am guessing that the Prius is similar in that it doesn't engage regeneration when bumpy because regen has as much decel in it as braking, and locking the wheels by the regen action would be similarly undesirable. So I reckon the brake blending issue is simply that the driver looses [unexpectedly] the extra decel from the regen, but not that the brakes themselves aren't working.

[Skipjack]

Thats what Toyota gets for outsourcing production to cheaper countries, such as the Czech republic. From what I heard the faulty parts were made there. No pitty for Toyota there. Shame on yout Toyota, those used to be some really good cars!

[chrismb]

Thats what Toyota gets for outsourcing production to cheaper countries, such as the Czech republic. From what I heard the faulty parts were made there. No pitty for Toyota there. Shame on yout Toyota, those used to be some really good cars!

Not really. An unreliable part is a factor, but any part can [and should be anticipated to] go wrong - this sounds like a single-point failure mode - that'd be poor safety analysis/systems design if it is so.

[blaisepascal]

Thats what Toyota gets for outsourcing production to cheaper countries, such as the Czech republic. From what I heard the faulty parts were made there. No pitty for Toyota there. Shame on yout Toyota, those used to be some really good cars!

Not really. An unreliable part is a factor, but any part can [and should be anticipated to] go wrong - this sounds like a single-point failure mode - that'd be poor safety analysis/systems design.

On of the difficulties that Toyota is having is that the absolute number of incidents are low, but the publicity attention has been very high. The relative number of incidents are so low that not only has the true cause escaped their pre-shipping testing, it had for a long time (and possibly still) eluded their post-incident testing.

Toyota has the worst-case scenario: a small number of their products are failing in an unknown way under unknown conditions putting their customers at risk in what has turned out to be a very public way. The public is asking for an explanation, and they don't have one yet. What should, could, they do?

Another blog I read pointed out that Ford has more cars under safety recall than Toyota, but isn't having the same PR issues.

[Tom Ligon]

Chris,

Americans sane regarding cars? Whaaaat?

I nearly cried when my wife decided our 19-year-old Plymouth Reliant was not a candidate for a total rebuild, and donated it to charity in favor of a Ford Focus. I was totally attached to the Reliant, which had developed the Laguna Indian name Kochinanako.

Some years earlier, my wife had asked her mother to give her the old 1969 Ford Falcon my wife had learned to drive. Myrtle had a leaky gas tank, the paint was gone, everything rubber was rotted, but my wife was sure she was going to restore her beloved old ride (until she realized how bad that beast was compared to Kochinanako).

It is likely the Prius does not suffer from a stuck throttle, but rather a bad cruise control. I found some material on the web, in which Steve Wozniak has apparently identified a problem:

http://articles.latimes.com/2010/feb/03 ... -2010feb03

I investigated a problem with a Chrysler cruise control that tended to stick in the Resume position. This resulted in acceleration in which it would not turn off when the brakes were applied. This same cruise control was on Kochinanako, but evidently with the sticking problem corrected.

I have experienced stuck throttles on at least four occasions on two vehicles, both old-fashioned carbureted machines. On one, lifting the gas pedal fixed the problem. On the other, both feet on the brakes stalled the engine (on that one the problem occurred when first starting up).

The modern runaways are not slowing down much when the brakes are applied, which I suspect will come down to the use of antilock brakes. You can't lock up the wheels with antilock brakes. They may just drag until they overheat and fade.

[chrismb]

I investigated a problem with a Chrysler cruise control that tended to stick in the Resume position. This resulted in acceleration in which it would not turn off when the brakes were applied.

Again, I don't really understand this as all european cars with cruise control come with a separate cruise-control switch that you have to manually operate before getting that function, and, obviously, can turn the cc off by pressing this button off.

Do US cars not come with such a switch, a separate cc isolation switch? (I am trying to think back to my hire cars and I rather think they didn't. Not sure I recall clearly.)

Also.... yeah, sure, I can believe many Americans may look at cars more that domestic appliances, but those who are more in tune with their cars would, I think, also be capable of figuring out a way to stop a runaway car due to that additional "mechanical sympathy". This was my point.

[blaisepascal]

I investigated a problem with a Chrysler cruise control that tended to stick in the Resume position. This resulted in acceleration in which it would not turn off when the brakes were applied.

Again, I don't really understand this as all european cars with cruise control come with a separate cruise-control switch that you have to manually operate before getting that function, and, obviously, can turn the cc off by pressing this button off.

If I'm understanding your description, it's the same, or similar, in the States. I believe the last car I drove which had cruise control had essentially 3 controls: set, off, and resume. "Set" used to set the target speed for the cruise control. You drove at the target speed, pressed set, and then CC would hold that speed, as long as the speed was greater than some threshold (I think 20-30mph). Tapping the break, or pushing off, would disable the CC. Resume would re-enable the CC at the last set speed. A common driving practice would be to use CC on the open highway, but break to slow down for traffic conditions, and hit resume when the roads opened up again.

I believe some CC systems also have a "boost", which would temporarily increase your speed by 10-15mph for passing. From Woz's description, it doesn't sound like "resume" was getting stuck, but rather "boost". He reported that it accelerated well above his current speed, but tapping the break would disable it.

[Tom Ligon]

The Chrysler speed control in question was a switch set on a stalk on the left side of the steering column. It had a slider with three positions, OFF, ON, and RESUME. RESUME was a spring-return momentary position.

At least, that was the intent. On some units the RESUME position would stick. On this particular design this defeated the normal function of the system which was to de-activate cruise control when the brakes were tapped. To correct the problem you simply slid the switch back to a normal position, but you had to realize it was stuck.

That was an old system from the early 80's, a mechanical servo and some sort of speed sensor and comparator, but no computer. Kochinanako was a 1985 1/2 model, and had the first Chrysler electronic fuel injection system, with a computer.

On most cruise controls I have used, you can goose the speed setting up slightly by hitting the resume button. What Wozniak describes is that repeatedly hitting the button to increase the speed setting triggers the runaway mode, which he believes is a software logic problem.

[chrismb]

If I'm understanding your description, it's the same, or similar, in the States. I believe the last car I drove which had cruise control had essentially 3 controls: set, off, and resume. "Set" used to set the target speed for the cruise control. You drove at the target speed, pressed set, and then CC would hold that speed, as long as the speed was greater than some threshold (I think 20-30mph).

No I don't think it is what I'm talking about.

I am talking about a totally separate button to the cc stalk, like a dashboard button, that is an isolation switch to the cc but can't make the cc work by itself. That way, if that dash button isn't activated then the column stalk won't work. Both stalk and dash button must be in a state for cc to operate.

[EricF]

Talk about a faulty cruise control, my '02 Explorer sport was recalled because the cruise controls were catching fire, in most cases while the car was off and parked in people's driveways

[mad_derek]

I can say that it isn't easy to decide exactly what to do when the car suddenly accelerates when you aren't expecting it. I've only had it happen once (in the early 70s) - I was driving a manual mark 2 Jag and had accelerated from some lights down a (thankfully) straight road in town. I got to third gear and the accelerator stayed on the floor when I came to change up ... oops. I obviously hit the brakes - hard - big mistake 'cos it didn't slow it down much. Obviously I should have put my foot on the clutch but I had visions of over revving engine etc. and it wasn't my car. My next idea was to put it into neutral - not happening - I'm not strong enough to shift gears with a large engine opposing a large set of brakes. It was only then that I thought to turn the bl**dy thing off - yes, panic happens. Turns out some noiseproofing felt came loose and jammed the accelerator down ...

I've still got that car out on the driveway (it was my Dad's at the time) but at the moment it's not moving at all under its own steam.

ChrisMB - some cars have that switch and some don't - an XJ6 doesn't but the later XJ8 does - perhaps they learnt something ... I just wondered what the point of it was, it certainly doesn't say in the handbook 'switch the cruise control off with this switch if it is trying to kill you'.