Run Away Prius a Hoax

Tom - The "brake assist" is described as an "emergency feature" here: http://priuschat.com/forums/newbie-forum/37699-priuschat-glossary.html . If your car appears to be "running away" IT IS GOOD to put it in neutral (someone was asking if it was safe).

My observation (experience) was that if quickly applied, the Prius supplies shockingly great braking power which would be very useful in preventing a collision especially since sharp pedal pressure is NOT required. My observation is that this feature disappears when the car is shifted into neutral which may explain the suggestion in the manual NEVER to shift into neutral. It is not hard. Why don't you try it?

 

Is this a serious post? You do realize how many posts I have made stating this exact same thing? That's why I think you may be joking, as I am one of the big advocates of learning to drive your car, which includes emergency shutdown and stopping.

If you aren't joking, then go back and reread this thread to get some context. This most recent reply was to another person having context issues, which is part of the problem with these online forums. The focus of a thread tends to drift around from post to post, then people come in late and are confused.

Originally I was correcting someone's misconception that B mode would be a good way to stop an SUA situation. It's not. Another reader took that post out of context and thought I was making a claim that B mode cuts power when the driver lift's his foot off of the gas. They correctly pointed out that lifting your foot off the gas cuts power.

I frequently simplify technical information in the interest of brevity, as long as it isn't the focus of the thread. If I didn't, all of my threads would be far too long and far too complex for casual readers of this site. We would need a Fred's House of Nerdy Engineers forum.

Getting back to the specifics of this post, I answered this question in the previous post, but for completeness I'll restate it here:

Brake Assist reduces reaction time by anticipating a panic stop. If the driver rapidly moves from the accelerator to the brake and brakes hard, the car assumes that this is a panic stop situation and *immediately* applies full braking force, rather than waiting for the drivers foot to continue the downward stroke. This shaves off a bit of reaction time. It does not, however, increase the braking force. Manually applying full pedal will produce the same amount of braking.

The statement in the manual against shifting to N while moving is for two reasons:

1) It is illegal in most jurisdictions.

2) It is possible to destroy MG1 from overspeed.

As I stated before, coasting in N is illegal for historical reasons. Older car designs could be difficult to get back into gear, and older brake designs were highly susceptible to fade. Those two factors made N dangerous on downhills. Neither applies with the Prius, although you do lose regenerative braking and engine braking while in N.

The MG1 overspeed situation is not likely to happen, but it can. It requires a narrow set of circumstances where the Prius is shifted into N at low speed while the ICE is not running, then coasting to high speed down a hill. The ICE cannot start in N, and with an immobile ICE, MG1 will be forced to spin faster than its design limit.

Tom

 

Regen or regen/friction "combined", into ONLY friction mode.

 

It's not a bug.

When does the car accelerate on the braking issue? It doesn't. It's a momentary lapse of braking. There is no random accelerations that I know of on any Prius.

And if they missed something in the programming/design, that still isn't a bug. Again, a bug is when things don't work as they are (thought to be) programmed to do. I don't think this is the case here. They may have fixed a flaw or addressed an oversight, but it was not a bug, it was working as it was programmed to. Calling it a bug is just going to make people afraid to drive any car that has any software and that's just fuels the false hysteria about the Prius, hell, about all modern cars. They'll think that something weird could happen at any time because of a bug that could randomly occur and that's not true. Vehicle software is contained, it's not like a computer, but people will think of all the times their computer did something truly bizarre because of a bug and shudder to think what might happen to their car due to a bug.

I agree that the brakes needed to be addressed and have posted that in the past. I am only saying that bug is not the proper term. Terminology is very important since it frames the debate. The media is already on the side of big business and a certain political mindset, we don't need to add to it, we need to work to frame the issues properly so as to avoid misinformation.

 

I suspect that the lady who invented the term, computer "BUG", would refer to this "improper programming" as a "BUG".

 

Well many suspicions are unwarranted.
Or are you saying that there is an actual moth in all the cars that experience this?

If it was programmed to do one thing and then did another, that's a bug. I don't think this was the case, but if it was then I'm happy to look at the info on that if you want to provide it.

 

I had dinner with Grace back in the late 1970s. She was a speaker at our annual meeting, and stayed for the dinner. What an interesting lady.

As for whether she would consider this a bug, I couldn't say. I do know that she would have had something pithy to say about it. She wasn't one to mince words or suffer fools.

Tom

 

"..annual meeting.."

For me it was a Simulation Council meeting (69, 70..??) at Bremerton Naval shipyard.

Nice lady.

 

And smart too.

Tom

 

I suspect what it is, was, to be called depends on the circumstances.

If someone went looking, trouble-shooting, for the problem as a result of customer complaints it would be called a "bug".

On the other hand if the customer complaint first went to the responsible programming team and someone look at the complaint and said "oh, damn, we screwed up the ABS' transitional braking computation due to the switch to rear disc brakes..."

But clearly, for PR purposes you would NEVER want to refer to it publically as a firmware BUG.

 

Since the GenII European Prius has had disk brakes since its introduction, it seems likely any sw requirement differences are well known.

 

But did the "hardware" engineers who decided to make the 2010 US Prius switch to rear disc even tell the firmware version/revision control team..??

Happens a lot in "my" world.

 

The Gen III Prius also has a more powerful geared MG2.

Tom

 

Bug definition by The Linux Information Project (LINFO)

This is the terminology I was using, and it is commonly use. The program was creating incorrect results. If you have trouble with the common usage of the word, just state it. You seemed to be implying that the braking behavior was correct. I used the current unintended acceleration problem as an example to find out if you would also claim if it turns out to be caused by software that it would not be a bug and operating as designed. It is an extreme example to try to get us on the same thought process. Yes, the braking problem that I observed was caused by what toyota called a "design defect". It is hard to reproduce and potentially dangerous IMHO. I never tried to cause hysteria. IMHO its much more destructive to have a product operating poorly, than for people to honestly look at the problem and the manufacturer look at it.

Try to learn the proper terminology, and correct people on that point if they are wrong. You acted as if the substantive nature of my post was incorrect. I was am using the term in its common context. I am not trying to spin to make toyota look worse or better. Your spinning of the subject matter does make it sound like you were trying to put out misinformation (the brakes were acting as design, stop complaining). I hope this is incorrect reading. And by the way, Toyota is big business and very political.

 

I stand by what I said and it is in line with the definition you provided. The car is behaving as programmed. The recall/fix is a software update that changes how the car is programmed. It now behaves differently, yet still as programmed. I haven't read anything that says that the car was not behaving as programmed. You yourself said it was called a "design flaw". Therefore it's not a bug if it was designed that way. There is now a recall to change the interval in the change of braking systems. It's been posted about, complained about and now Toyota is addressing it, so I don't understand why you said "IMHO its much more destructive to have a product operating poorly, than for people to honestly look at the problem and the manufacturer look at it."? I agree with that, I never tried to shut down discussion of the braking issue so hopefully that wasn't directed at me. I honestly have only read that the brakes are operating as designed/programmed but that there was a flaw so they are now fixing that. That just isn't a bug.

I was merely addressing the fact that you keep calling it a bug which I believe to be incorrect. I explained in my previous post why I think that is detrimental, I don't recall ever accusing you of intentionally causing hysteria. I was merely pointing out that that is my reasoning for not calling everything a bug when it was behaving as it was designed and programmed. Too many people will start wondering if their car is going to crap out like their computer does, or worse. I don't even remember what else you said in the original post I referenced.

Unintended acceleration is a non-issue in the Prius from what I've read, so that is a hypothetical and does not provide a proper analogy to the brake scenario. Maybe that's what you thought I was discrediting?

(But to answer anyway, yes, if SUA in other vehicles is determined to be software related in that it isn't behaving as it was programmed to, that would be a bug. But that is a completely different situation than the brake issue, which is not a bug.)

And I agree, Toyota is both those things, but our media is owned by other corporations and a lot of posters here have stated their belief that the media and politicians are attempting to smear Toyota to help GM. I don't know if that's the case or not, but I do know that based on the data of recalls that Toyota is not getting a fair shake since they are nowhere near the most problematic manufacturer, but you'd never know it from our media. Our media is also ratings driven - infotainment - so they have to try to get people to watch and Toyota is the new pit bull. And anyone who has ever met a few pit bulls know they are nothing like what the media would have you believe, but if they showed them being sweet and cuddly - as they mostly are unless they're abused - it wouldn't make a sensational story.

Anyway... this has been a lot of talk over just one word.

 

Tom - I just came from my Prius. I realize now that the conditions for operation of brake assist, rapid transfer from accelerator to brake, do not apply when the accelerator has been released for a more than a second. In neutral, the engine will simply race if the accelerator is applied so the instinct is to release the accelerator, thus canceling brake assist. Even your descriptions do not recognize this. You simply say that you "do not see any mechanical reason why putting the car in neutral should cancel brake assist". THAT is the cause of this exchange. THAT is worth understanding. And brake assist IS sharply noticeable in brakeing force related to pedal pressure. I have hand controls which make virtually instant transfer possible and have been shocked!

It still remains a good set of rules. If the car seems to be running away PUT IT IN NEUTRAL. Otherwise DON"T. It is not possible to say this too often.

 

The majority of people did not complain because there is no problem. People in general are stupid. Millions and millions sold, far less than a hundred complain. There is no reason to warrant a major review of the ABS firmware over this. People complain all the time for no reason. There is a guy on here that complains because the emergency jack included in his car isn't sufficient enough of a jack to change the oil (as stated in the manual dont use unless an emergency). There are people that complain it is Toyota's fault they run out of gas when the car not only has a guesstimation guage but a blinkng light near the end, and a final warning both audible and visual. These are the types of idiots that Toyota has to deal with as well as any business large or small. A few people out of the whole customer base isnt going to do anything for any company.

 

How about this? The majority of people did not complain because they did not experience the braking issue - or as I call it bug. When those that took them to the dealers, the dealers could not reproduce it because it is hard to reproduce.

Toyota does not count complaints to dealers in the hundreds of reports sent to the japanese and american safety agencies. They did get enough to investigate and fix the problem. As Toyota told the Japanese safety agency, they had a fix to the problem in new cars when the agency officially started an investigation. In other words there were enough complaints for toyota to review the software.

As a product manager, I never would say bug in any external communication, but we certainly used the term internally.

 

Let's agree to disagree on terminology. You obviously did not experience the - defect, issue, problem - or you would have been more concerned about the nature of the post then the term I used.

There was a software problem, Toyota fixed it, people are getting the fix. But when we are more concerned about terminology instead of defects we get the kind of safety deafness that has caused many of the problems at Toyota. Mr. Toyoda had a similar statement in his apology for the recall. The recall notice says - Important Safety Recall. I am glad you are not one of those that is implying that its a fake fix to appease the media.

I think it is likely software or electronics is causing some of the SUA. The proper fix remedy is to give the vehicles a brake override of throttle. Toyota is now in the process of doing this. They still need to honestly examine their products to determine if they have defects in electronic or software design or implementation to determine this.

I seriously doubt that GM or the US media was responsible for the Japanese government investigation of Prius braking issue. The media grabs a hold of a story and exploits it, this is true for all of the automobile companies.

 

brake over-ride did not help these people with Priuses, did it?

I doubt it will change your opinion either.

there is always "if" and "i think".

When they implement brake over-ride, people will say it failed... when black box data is shown, people will say it is false... when police confirms the story, people will ignore it.

by people, i mean those who have vested interest to do it and those who simply do not want to believe otherwise.

it does not really matter, all these prius stories have been proved as false so far.

i might think that tomorrow someone will give me million dollars or that i will be hit by meteor, but that does not make me right, does it?