Does the Prius have a transmission?

Of course it's a "transmission". A transmission doesn't have to change gears or have some kind of clutch device. BTW, there is a "clutch" like device in the Prius, it's the torque limiter, which has a clutch like disk and a pressure plate (with constant pressure).
A transmission transmits power, changes the input shaft to output shaft ratio of rotation, and may or may not be able to couple or decouple the power input to output.

It's just that the Prius has one you can't directly control. "Shifting" from "P" to "D", "N", "B", or "R" changes little in the transmission, it's the electronics that's "modified". Though I suppose engaging the park lock device could be construed as "control" and a change.

But there are no gears to be "shifted". They are all permanently "engaged" in one ratio. The "gearing change" necessary for proper operation is done electronically by magnetic slip.

 

Officially, Toyota calls it (GenIII) a 410 transaxle assembly...and it DOES have meshed gears, just like normal "shifting" transmissions, except that with the planetary (ring, sun, planet) CVT there is NO engagement/disengagement motion (ala' clutch or torque-converter).

Instead, gear-ratio is controlled via selective over-/under-drive speed-control of the planetary-gear assembly, resulting in ALMOST infinite gear-ratio adjustability. There is a MIN and MAX ratio, but anything between them is infinitely available & adjustable.

 

I would claim the Prius has a single ratio clutchless transmission emulating a continuously variable transmission by altering multiple power sources and loads in software. Since nothing 'shifts', manual and automatic lose their meaning.

 

It's a transmission. Done.

 

I have read that both of those transaxles pictured above are made by the same supplier for Toyota and GM.

However, a decade of technology separates them.

 

Before automatics were invented, the term transmission was simply just called transmission and they were all manual. On after automatics were invented did they move to being called auto, manual, and now CVT.

By the literal definition "the mechanism by which power is transmitted from an engine to the wheels of a motor vehicle." Yes, it does have a transmission. It has gears which increase and reduces ratios until it gets to the wheels. It's able to very ratios of power from the 2 input sources via software control of MG1, whereas in a traditional transmission, you change ratio of power from the source via gear changes. It's doing the same job, so it's a transmission.

 

The question misses the point of why "transmission" comments have been made.

Of course there is transmitting of power, but it works more like a differential rather than something actually shifting gears.

A quick look at the complexity of other systems is why.

It's the simplicity.

 

Exactly, that's why the description "planetary CVT" is the best simple description; there is no shifting, just planetary "ratio'ing."

 

Prius uses a E-CVT ie planetary gear setup, and the ratio is electronically controlled. The the split power device ie planetary gear is sandwiched between engine clutch MG1 and MG2 , and it uses a gear (instead of belt) to connect to drive axle.

The Volt uses a 2 speed planetary gear, it has 2 drums and clutch packs, the first gear is used primary for the generator to power the electric motor, the second gear is used for maintaining highway speed it at 70 mph using the electric motor and the engine acts a double duty as powering the wheels and providing charge for the electric motor by engaging the motor generator.

 

Yes, instead of bands, friction clutches ,and sprag one way clutches to hold rotating gear masses, the Hybrid uses magnetism by introducing electrical current into the coil windings. An automatic transmission never engages gears, they're always engaged , they just get held, so something else can spin, which changes the gear ratio to the output shaft.

 

A majority of manual motorcycle transmissions don't use transmission fluid at all. The motor oil does double duty and also lubricates the transmission.

 

The major advantage of more software control is the fact that when you work out all the bugs and get it right, for the most part it always works beautifully. And if a problem does pop up, it's an easy fix to implement on all vehicles. A very low cost recall. Mechanical fixes rarely happen, and only happen to the next model year, or if there is a severe safety danger to the passengers.

And one might argue the prius design is mechanically simplistic because all of the gear are stationary and simply just spin, there's no movement of gears. So really the only part to break are the bearings, and the clutch to the motor could potentially wear out, but not likely. Though in the 2nd gen, they did have some clutches that broke from their backing plates i believe. They designed it as one peice in the 3rd gen i think.

Here's a good video:

 

Of course it h

(sorry about last post, there was a bug...)

OK, back at it again.

Of course it has a transmission ! How else would the motors/engine move the car otherwise? What it does NOT have is a gearbox.

 

Technically it's a Transaxle. The differential is in there and the axle shafts plug into it.
It's a box of gears (that never shift) and bearings, two M/G's (a big one that powers the car forward or reverse and a small one that controls the engine RPM when the engine is adding power or uses power to keep the engine stopped when it's emulating an EV), a small oil pump (but no filter or magnetic drain plug to catch the crud) and 3 seals to keep the lubricant in.
It's a gearbox. It was designed in the '90's.

 

Again, the point being missed. Semantics don't matter. COST does.

Prius does a far better job of delivering an affordable choice than Volt when it comes to the device which transmits power.

 

john,

I don't follow.
Cost is measured in: $0.00 per Mile. Correct?

If you drive less than 40 miles before you can plug-in, you never have to visit a stinky gas station.
EV driving, in all 4 Seasons, is always less expensive than burning gas and its related maintenance needs.
(edit: unless you live in Hawaii, $0.36/Kwh, or other high E-rate locations.)

If you drive 500 miles a day, a Prius is the car for you!

 

The price of the vehicle must be included in the equation for accurate representation of impact to the owner. That means PRODUCTION COST plays a major role.

Toyota worked extremely hard to deliver a hybrid system capable of competing directly with traditional vehicles. That means it must be profitable and not depend upon government subsidies.

Remember, the goal is to replace traditional vehicles with cleaner and more efficient vehicles.