Weird issues after getting the recall update?

Except you were the only one street racing there.

 

I think the real issue for all of us is that the software mod will reduce the number and/or levels of thermal stress cycles at the IGBT die interface, but it will not eliminate them. Some level of thermal cycling will continue and the affected vehicles may have incipient damage from operation with the current software. My early-production gen III is essentially the earliest of the vehicles affected , it has about 60,000 miles on it, and this is about typical. 451 failures out of a large population doesn't seem significant, but this population of vehicles has relatively low mileage. What if they all continued to 120,000 miles without the mod. What might the failure rate be then? Perhaps Toyota has been able to estimate this?

 

...as it raced over the top of the Prius from the stoplight?

 

This is my thinking. My inverter failed at 70,000 hard miles. Private or low mileage owners may have damaged but working inverters which might give a few more years service but ultimately fail. Toyota have probably predicted a major number of future warranty claims, hence the recall.

 

They should provide us with an inverter that is designed for harder use and little chance of failure rather than turning the Prius into a slow turd

Mike

wanderin around on my phone

 

Everything fails from use eventually. So any idea that the inverter should be "redesigned" so it won't fail is wrong right from the start. The question is will it last until the car is recycled?
I'm not sure where the posters are getting the "number of failures so far" figure. Making it up? Failures on members of this forum?

 

I've just posted in another thread about how revvy the engine now is and that the surge in Power mode is no longer, or at least no longer like it was!

I wouldn't say I'm unhappy, but I'm not impressed. The confidence of being able to floor it past trucks when doing 50 mph has now gone. It drives like a car with 110 bhp now.

I wonder if anyone has the opportunity of putting a post recall car on a rolling road to test the power output. It doesn't feel like 130 bhp any more that's for sure.

 

Imagine having the 17" wheels which make the car slower with the original software, then have it updated to the slow turd software. It might be faster to walk

Mike

wanderin around on my phone

 

Reading this thread makes me not want to do the recall and wait until my inverter fails and then get a new one. They can do the recall at that time

SM-N900P ?

 

I doubt it would fail unless you use the car for taxi service. Just keep your car out of a Toyota dealership and it wont get updated.

Mike

wanderin around on my phone

 

The basic question is as follows: "Did Toyota change the controller software so that acceleration is impacted?"

On a previous thread I pointed out that there could be changes that wouldn't affect maximum acceleration. For example, during the initial onset of flooring the gas pedal, the rate of change of acceleration could be reduced, allowing the heat sink and transistor temperatures to equalize; at that point full acceleration would kick in.

By the way: There actually is a formal name for this. The sequence goes:
Rate of change of position = velocity = d(x(t))/dt
Rate of change of velocity = acceleration = d2(x(t))/dt2
Rate of change of acceleration = snap = d3(x(t))/dt3
Rate of change of snap = jolt = d4(x(t))/dt4

(Inertial navigation systems use all those... especially if one is trying to keep track of where one is located. Fun.)

People do notice snap; you can't go from no acceleration to max acceleration without it. If my hypothesis about the transistors-breaking-off-the-heatsink-due-to-second-order-effects is right, accelerating itself isn't precisely a problem. Yeah, more power is going into the engine, but, at base level, that's no different than, say, trying to go 120 mph down the Autobahn.

Limiting the amount of snap would control the difference in temperature between the transistor die and the heatsink and reduce that second order temperature difference effect. And, since the controller is a digital signal processor, it should have no trouble calculating and limiting snap.

On the other hand: Calculating higher order differentials is a noisy process (noise is amplified), so the algorithms to provide a smoothed snap to some detector get, well, interesting.

A simpler solution would be to simply monitor the difference in temperature between the heat sink (I think they've got that) and the transistor die (think they've got that, too); if it starts to exceed some limit, then push back on the electronic throttle. This has the advantage of not depending upon new, noisy algorithms, and naturally keeps the transistors out of the stress area, since it's delta-T that's the issue.

So: doing either of the above would reduce snap. And people can definitely sense snap with their inner ears and kinesthetic sense (that's muscle tone and body position). I'm guessing that we're not as good at that as detecting the amount of acceleration. But, for that matter, human beings tend to be lousy at figuring relative amounts of acceleration. I keep on remembering an incident out in Arizona during a foggy/cloudy night, when a flight of fighter jets augered into the ground. They had been in VFR, got into the clouds, and were depending upon their seat-of-the-pants feel to figure if they were going up or down. They were going down, as it happened - but they didn't detect that because the jet thrust was up a bit, so they were accelerating, and that acceleration cancelled out what should have been noticed as a nose-down attitude. Two of them crashed, I think, and the third managed to get the nose up.. All fuzzy memory of reading a Naval Air safety magazine some 30 years ago. All of which explains why pilots are highly dependent upon that turn-and-bank indicator and the other IFR instruments. They truly cannot trust their own senses. Human beings are evolved to Not Fall Down when running or walking with their own two feet. Put them in a vehicle and I think it's a major accomplishment that we don't whang straight into the nearest tree. (And people do that, too.) A combination of instincts and learned behavior, maybe.

Which is why I'm waiting for somebody with a scan gauge, accelerometer, and the right kind of test track/roads to do a before-and-after update performance check on the Prius. Or maybe if Toyota, out of the goodness of their souls, might post some data.

Like others have said: The perceived changes might just be that our excellent tools of pattern matching are looking for an expected pattern that matches what myself and others have theorized what the changes might look like. We're really good at pattern matching, the better to detect a lion or bear hiding in the tall grass or shubbery. The occasional false positive might make one do an unnecessary jump, but it's better than a false negative, which means one gets eaten.

Even if the effects of the change are real, as has been previously pointed out, there have apparently been a number of on-going updates to the inverter firmware that have been rolled out over time, making differences between driving different year Priuses. After this change, we'll all presumably for the first time be driving models with the same firmware load. Which means that somebody driving a 2010 with an update might simply be experiencing what somebody driving a 2014 Prius has been experiencing already.

I really, really, really want to see some hard data before we all go crazy around here.

KBeck

 

I think the motive is liability. Say inverter blows while you trying to pass on a 2 line road and someone gets killed. The black box shows inverted failure before the impact. Huge multimillion settlement and huge negative publicity for Toyota (again). This is what Toyota is aiming to avoid. The actual number of inverter failures reported on PC is not that high. I remember only several posts. There could be some I missed of course.

 

I had the recall done a couple of weeks ago and I did notice that the car seems slower. It seems like you really have to give it a lot of gas to get going up a hill and the power seems to come on less linearly. I haven't really been paying attention to my FE but I will look more closely.

 

I think you may be the first with the 17's to check in with this software. It would be good info to know how the car merges into traffic and so forth with the heavier wheels/tires. With the original software the 17's already slow the car down significantly verses a 15" wheel/tire Prius.

Mike

 

If liability is the reason for the update and the reported loss of power is a result, it seems that they're going to have a lot more negative publicity. If the car now won't get out of its own way and drivers are used to a certain level of acceleration, someone's liable to get killed in a failed attempt to pass something that, up until the update, would have been easily accomplished.

 

It doesn't seem to be problematic. You just need to give it more gas to get up to speed, I'm just not used to pressing the gas that hard to go. The car doesn't seem any slower under full acceleration.

 

Today I was driving the rental in ECO mode which so far seems to be the only mode that gives decent mpg's. I was able to average 41 mpg running from 65 to 85 mph for a 145 mile distance in 25F air temps. I also tried pulling out in traffic that was running 65 mph or so and just gave me what I would call normal distance to accelerate without getting run over SO I pulled out from a stop and had that Go Pedal mashed to the carpet and was able to get up to 70 mph in a reasonable distance without having anyone try running me off the road in rage

So the car did hold it's own against the Minnesota leadfoots today. It still is a turd to drive but it was safe. I did some two lane passing where I had a mile or so of wide open road to be safe and although the car struggled to get to 85 mph, it did and I was able to get around others safely

It is just a shame the inverter wasn't upgraded rather than turning back so much of the awesome electric torque the car had with the original software. Gone is the big woosh of electric torque. I just wonder now with 10k mile oil change intervals and a gas motor that is being worked much more than it was when the oil change spec was published. I personally would never take my car to 10k miles between changes but there will be many that do 'cause Toyota says so. Maybe it will be fine. Don't know...

What would be super cool would be a killer strong inverter with a wicked hot Hybrid tune to really throw the electric torque to it. If a guy could get his paws on the original Hybrid computer software and the latest cut to do a comparison to see what they did to turn down the torque, then develop a version that cranks up the torque to run with a rebuilt inverter that is built to handle a beating. Prius could have Mad Powa then

Mike

 

Passing has always been an issue for me even before I had the update. It seems exceptionally slow going from say 60 to 85. I always make sure there is PLENTY of room for me to pass. I have never had 15"s so I don't know what to compare it to. I will miss the torque. We'll see what the Gen IV Prius brings!

 

I understand the Gen 4 will have more power. Maybe it will have the same power as the original Gen 3 which will be more than the current Gen 3 so more power

Mike

 

You must work for the IRS!