hmmm, if he was doing 90mph, I would expect that the trooper would be observing his brake lights for more than a few seconds.

Anyway, "half an hour at that speed." That is suspect. ...in a balloon-boy sort of way. --like someone posted, you have to be an idiot to now not know how to shut down a Prius --should you own one. (maybe the system faulted and he decided to milk it)

Now about this "gently ride the brake pedal" ...my understanding is that the regen-braking is then engaged (the electric motor then becomes a braking generator) And, the friction brakes are the last thing to be applied. --No?

What am I missing? Does the regen-braking turn off /dormant at highway speeds?

As to what happened, to us it's all speculation, based on reports.

Who saw what, exactly how it played out.

But if we're speculating, my spec is he is making it up. There's just a lot of red flags. His shady past is one. His inability to reasonably explain why he didn't put it into neutral like the cop told him to ("I was afraid the car would flip over," lol). The silence when the operator told him to stop the car by holding down the start button for 5 seconds and his refusal to do it. etc.

We'll see how it plays out.

well yeah, that's what makes this fun. :cool: ...kind of a speculation sifting process.

So far;
1) Toyota has design issues. --no doubt. The engineers here see it clear as day.
2) The latest 90mph for a half-hour guy is suspect in a system-gaming kind of way.
3) People can be massively in debt even if they save all that money by driving a Prius. ;)

Agree on all 3! As to 2, there's little doubt this guy as engaged in "system gaming" in the past, it's part of his M.O. Whether he's done it again this time . . .

Here's one of the latest articles, which gives a good summary of the guy's past, some good links and a poll. Vote and see the results (almost 100K have voted so far).

http://autos.aol.com/article/prius-driver-scam

According to the owners manual, the regenerative braking kicks in as soon as you take your foot off the accellerator pedal, before you step on the brake pedal.

Look, I am not trying to defend this guy. But the smear campaign against this guys seems to be in "overdrive".

Newsroom : Toyota Prius Vehicle Throttle and Brake Systems: Myth VS. Fact / Toyota

Well, there is certainly misleading information from Toyota. With the CVT (Continuos Varible transmission), there is no mechanical separation. The talking points about a disconnecting the engine from the drive wheels, and WOT engine runaway in neutral, wouldn't apply to this kind of vehicle.

I do like that fact that you have to hold the on/off button for 3 seconds to get it to turn of the engine. You also have to HOLD the shift lever in neutral for at least 1 second to get the computer to disengage the engine/motors.

I agree with Red. Toyota and it's bastions here are engaged in EXACTLY the sort of witch hunt vs this guy as they cried foul about for the several weeks since the media and the US Gov't finally got serious about investigating Toyota.

Hyyyyypoccccccriiiiiitttteeeesssss.

interesting about that "HOLD the shift lever in neutral for at least 1 second" bit
From Toyota HYBRID SYNERGY DRIVE: Regenerative Braking

http://forums.pelicanparts.com/uploa...1268523430.jpg

Credit to Toyota for trying to make that work (smoothly, I assume). I would have advised that they put all of the engine-braking in the throttle and had conventional brakes. (separate) --That was my advice in the early 90's for an SAE (school) hybrid project. Of course, that was easy/obvious advice as we had very little budget.

It would be kinda contra-productive in terms of saving energy to make a car brake as soon as you go off the throttle
makes it hard to coast, and coasting as far as i can tell, is quite good for fuel economy

regen braking turns kinetic energy into electric energy, which is fine if you had to decelerate anyway, that energy would have been lost, but still means a percentage of that kinetic energy goes lost in the conversion...
It cannot regenerate 100% of the energy.

When driving with fuel economy in mind, the whole point is not accelerate to quickly...
but also not to brake... braking is a missed opportunity for fuel economy... one can prevent it by anticipating more in advance, and coasting instead...

So it just does not make sense from a fuel economy standpoint, to have regen braking kick in simply because the foot is of the throttle pedal...there's always that percentage that can't be regenerated...

coasting ... the computer would control the needed load, or lack of load. That is, you wouldn't lift quickly unless you want to slow quickly. ...like a 911 in 1st or 2nd, if you want to slow (w/ the engine engaged) you let off as needed. With the Prius, it would be sucking up most of that energy.

If you've played with regen motors you know that they do a great job of braking right up to the point where you've really slowed . . .and then you've got nothing, and have to use friction brakes. (assuming you want the most efficient regen, and don't want to use electrical energy to motor brake) Anyway, I expect this is why Toyota approached the braking the way that they did.

I think the guy is full of $#it

Unintended acceleration with a Prius?

1) step on the brake (which he claims he was doing)
(Video shows the brake override working)
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OR

2) Shift into neutral (which he was instructed to do)
<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/II_03lbr-Jw&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/II_03lbr-Jw&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>


OR

3) Turn off the car (which he was instructed to do)
<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/3N22LLJsChA&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/3N22LLJsChA&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>

Dude didn't get his Prius stopped because Dude didn't want to, at least until the news helicopters were there.

Yeah Jake, great videos. Next time someone post their computer with a recurring blue screen o' death maybe you can post a video of how easy it is to make a computer to work w/o the BoD.

Seriously, what's with all of this "See, it works" stuff?

Because I think the runaway Prius was a hoax, and if he'd have stopped the car if he'd done exactly as the 911 dispatcher, and cop on a bullhorn, had instructed him to do. Except he didn't want to.

I don't doubt for a second that Toyota has a *serious* problem with unintended acceleration, and that it's likely a software issue. But I think this particular case is a balloonboyism.

So do you rule-out the possibility that his computer did malfunction, and he seized the opportunity to balloon-boy/OJ the situation?
... Or do you think that drama was priusmeditated?:cool:

I think it was priusmeditated. Seriously, to me this guy no more believable than balloonboy's dad. Listen to the bits of the 911 call, and notice how he doesn't even acknowledge the instructions he's given, yet he stays on the phone for 20+ minutes in a "panick"?

The guy strikes me as a desperate attention w#ore... he holds a press conference afterwards? My BS meter is off the scale.

This particular incident may be. The other thousands of incidents....probably not.

agreed.

As I stated in another thread, I have been a BIG Toyota fan for years. However, something is definitely wrong with Toyotas, and I don't buy the gas pedal explanation. And aside from the UA issue in particular, I think Toyota has some larger QA problems to graple with.

One thing I notice is that the brake caliper & rotors are pretty small.


Per an article I found on the internet:

There are two braking systems on the 2010 Toyota Prius. The first is a very conventional set of four disc brakes, 10.09-in. up front and 10.2-in on the rear, actuated by hydraulic fluid pressing on pistons located in calipers…y’know. Brakes. Except these have aluminum calipers and a resin piston, all designed to reduce weight.

The other is the regenerative braking system, which relies on the resistance of the electric motors. This does a couple of things. First, it slows the car, but not entirely; you still need those discs and brake pads for that. Second, while it’s slowing the car, it’s feeding electricity back into the car’s battery system. Recovering this energy is key to any hybrid’s operation. The lower the battery, the more the Prius biases its braking toward regenerative. As a side benefit, since more of the braking is done by the drivetrain, brake parts tend to last longer on the Prius.

http://forums.pelicanparts.com/uploa...1268534787.jpg

It feels just lake a "normal" car. You can push the brake pedal down to where the brake lights come on without doing any significant braking if you are at highway speeds.

interesting. so at what point does the throttle cut out? (like in Jakes first vid above) I would expect that to coincide with the brake lights. -apparently not.(?)

Beats me. You really cannot tell because it is so quiet...but it "feels" no different to the driver than any other car. Perhaps there is a "flywheel" effect of sorts that smooths out transitions. Unfortunately, I did not really think to observe that when I was driving, but clearly, the car would be difficult to drive if it did not effectively emulate a "normal" car. According to one article:


"Operation of the hybrid combination is seamless and virtually imperceptible to the driver and passengers. It five main operating modes are:

1. When pulling away from a stop or under a light load, only the electric motor powers the vehicle.

2. For normal driving, a combination of gasoline and electric power is used.

3. Under full-throttle acceleration, the electric motor receives additional power from the 40 batteries.

4. During deceleration or braking, the electric motor functions as a generator to recharge the batteries.

5. The batteries are regulated to maintain a constant charge. When charging is needed, power from the engine is used to drive the generator. This eliminates the need for an external charger or power connection.

The key to the Toyota Prius system is a power split device in the transmission which sends engine power either directly to the wheels or the electric generator. The generator, in turn, powers the electric motor and recharges the batteries. The power split device uses a planetary gear to constantly vary the amount of power supplied from the engine to either the wheels or generator. The electronically controlled transmission controls engine speed, generator output and the speed of the electric motor to handle changing driving modes.

The system is designed to keep the engine running within its most efficient rpm range. When increased driving loads lug down the engine's speed, the control system shuts off fuel to the engine and kills the engine. The electric motor then takes over and provides 100 percent of the driving power. If additional power is needed, the engine is restarted and adds its power output until the extra power is no longer needed. At that point, the electric motor cuts out and the engine resumes its light load operation in its optimum speed range."