CVT freewheeling issue

nope

 

So the Prius/Toyota Hybrid Synergy Drive utilize a eCVT that is a planetary gearset rather than a belt like traditional CTV transmissions

 

The Prius power split device, commonly referred to as an eCVT bears no resemblance at all to a traditional CVT or an automatic transmission. No belts, no bands, no torque converters, just some planetary gears that are always engaged and a couple electric motors to propel, charge the battery, or otherwise get the energy flowing in the right direction. It's pure genius.

 

What causes the trans to shudder at low speeds and at the speed limit when you ingauge the eco mode hybrid system, sometimes it's so violent shutter, have only I have only 7K miles on a transmission flush, my 2011 Prius has 230k miles on it,shows no codes

 

probably a clogged egg circuit

 

As I said, it's not a transmission. You can replace the fluid, but there's no flushing involved; just drain and fill. The shudder is from something else. Could be something in the EGR, could be a CV joint. Who knows. You'll have to either investigate or hire someone to investigate.

 

Or something in the transmission itself, like a winding defect; that'll have a magnetic interaction with the rotor, feels like cogging/shuddering. I agree, guessing won't be the way to find out; has to be investigated.

I've never quite understood the "its not a transmission" mantra; what do you call a thing that carries (transmits?) power from an input shaft to an output shaft, while varying the torque/speed ratios from what the source provides to what the destination needs? There's any number of different ways to build things that do that, and they're all transmissions.

The best I can make of it is more like "it's not the kind of transmission on your grandpa's car, with clutches and bands and whatnot", which is a thing worth saying, but it's a different thing. (Also see the play Fear of Flowers by Neil Martin.)

Some purists will insist on calling it a transaxle, but just because that's the jargon-y word for a transmission combined with the final drive and differential ... not because it isn't a transmission.

 

i think jerry just meant it isn't your fathers transmission

 

I sympathize with the idea it is not a transmission.
No gears ever change.
No clutches ever engage or disengage.*

But it is a software transmission, the computers emulate the function of a transmission even if the hardware is missing.

* There is a clutch (torque damper) between the engine and transaxle solely to protect each if the other locks up or suffers a sharp change of speed. It is neither driver nor computer controlled.
The Prime has a sprag (one way) clutch so it can use both M/Gs to power the car.
Sprag clutch - Wikipedia

 

Just what's being "emulated", exactly? It straight-up does the exact thing a transmission of any kind exists to do: take input at one torque and speed and output the same power at a possibly different torque and speed.

 

Normally there would be quite a lot of hardware to 'take input at one torque and speed and output the same power at a possibly different torque and speed" The HSD does it via software, with one planetary gearset and no clutches. Despite never changing the gear ratios, it emulates a CVT.

Compare this to an automatic transmission, with multiple planetary gearsets and clutch packs. (the torque converter and valve body are not explained in this video, so it is a simplification)

 

It is a CVT. Power comes in one end, turning a shaft at some speed with some torque. It gets Transmitted to the output shaft, which can be turning at a different speed, with a different torque. The ratio between the input and output speeds and torques isn't limited to 4 or 5 or 6 fixed selections, but is Continuously Variable.

That's what a CVT is. How you build it is a different matter.

You can also build a CVT using other combinations of technology, like cones and push belts. If you build one like that, congratulations, you have also made a CVT. They are different, but neither one is "emulating" a CVT. They are both too busy flat-out being CVTs.

This line of talk is like getting hung up on how a propeller airplane happens to work, then saying a 737 isn't an airplane because it lacks the propeller, but it uses jet engines to "emulate" an airplane.

Fiddlesticks. If it's a powered, winged craft that flies, it's an airplane. How it does the power thing might vary from one plane to another. Electric ones might come along someday. They won't be "emulating" airplanes either. They'll just be flying around being airplanes.

 

It all started out when I had a misfire on 3 I put a new EGR valve on clean the EGR cooler new spark plugs and change the transmission fluid hey I'll have 7,000 miles on them just developed a shutter especially at highway speed when it tries to engage the electric motor just wondering if there's some kind of solenoid inside the transmission that is stuck

 

I'm just wondering if the 12-volt battery is about gone because when I'm sitting still the hybrid batteries are all full according to the gauge on the dash the motor will crank up like it's trying to charge the 12 volt system I may change it they say the 12 volt battery does crazy things to these Priuses

 

Nope, no solenoids in there. Nothing that moves except the motors and gear train (and the parking pawl; you'd know if that were stuck 'cause the car wouldn't move).

The engine doesn't start to charge the 12 volt battery. That battery is always being charged from the high voltage system, whenever the car is in READY, at the same rate whether the engine is running or stopped.

The engine will start whenever needed to replace charge in the high-voltage battery, or for various other reasons to do with heating, or maintaining operating temperature and emissions parameters. In general, trying to second-guess why it is starting at some time or not another is that late night with beer kind of question: fun, only most of the information you'd need to answer it is known by none of the participants.

 

easy enough to test the 12v health, wondering is unnecessary

 

Checking the 12 volt battery voltage tells you the 12 volt battery voltage. It makes wondering unnecessary, if that happens to be what you're wondering about.

 

What @bisco said. You and I know, Chap, that technically, it is a transmission as are lots of other things not usually thought of in those terms. But most people, when they think "transmission," are limited in their imaginations to a traditional automatic or manual -- at best one of the newer trannies that can be run either way. Belt driven CVTs are getting common too. And I think Subaru has a chain driven CVT.

But the Prius transmission is so unlike any of the others that it's hard to describe without a video, and then it's hard to really comprehend. I think that's why so many people just carelessly use the shorthand description to introduce the topic.

As to @Granny hill hot rods issue, I agree that it's going to take hands on investigation. Guessing won't fix it.