So I signed up for a 2 day subscription to Toyota TIS. I thought I would share a couple of things that I learned about the P610 trans-axle. The PSD is definitely lubricated by the engine driven transmission oil pump, when the engine is off then no lubricating oil is fed to the PSD. I would assume that lubrication when running on the electric motor only is accomplished simply by the oil that remains in the PSD. All other gears and bearings are splash lubricated from the differential gear. There are 5 catch chambers above the gear train and the MG units. At the bottom of the catch chambers there are holes that allow oil to run down on the various gear train components and the MG units to lubricate and cool them. The bottom of the differential gear sits in the ATF and splashes it up into these catch chambers. It's a pretty simple yet effective way to lubricate when the car is driving on electric alone. ATF cooling is accomplished by a liquid to liquid heat exchanger. The coolant used comes from the inverter cooling circuit. No cooling occurs when the engine is off due to the fact that the trans-axle oil pump is not turning. Just a fun fact, the inverter cooling pump delivers a minimum of 10 liters per minute.
The biggest change is the liquid to liquid heat exchanger, and the new layout of MG1 and MG2. I'm not sure how the previous gen handled lubrication when on electric alone, I have not looked that up yet.
Well I just looked and the previous gen uses splash lubrication and catch chambers as well, hmmm so much for it being a new feature
This is the CVT cooling and lube system. There isn't a traditional CVT in these types of hybrids. The planetary gear in the transaxle is manipulated by varying inputs from the ICE and MG1 to act like a CVT. This is why it is referred to as an eCVT.
No, there was a chain to the differential in Gen 1 and 2, but in Gen 3 and beyond it is all constantly meshed gears. (there is a one way clutch added to the Prime) Gen 2 on left with chain, Gen 3 on right with gears
The Prius transaxle uses the name eCVT, is really different than a tradional CVT. All it has in common is that there's no shift-points. "4th" generation at the introduction, but it's first through third gen's covered. The video was posted in 2012, very interesting, in-depth description of the various Prius transaxles. Not sure why, but I always nod off for a bit while watching this and similar by the same author:
That's a traditional CVT. Many reviewers and reporters get lazy and refer to the Prius and other hybrids as just CVT, but they are really CVT in name only, because their operation behaves like a CVT to the driver. Then for further confusion, some hybrid systems(Honda's older one, and maybe Nissan's) were mated up to a traditional CVT. Unless the discussion is about a discontinued Honda IMA hybrid, the hybrid has an eCVT, which is physically different than a CVT.
Thanks Mendel! I've seen it before. BTW, I have posted gen 4 trans-axle presentation in the other thread. It is not linear like 1-3 gen but side-by-side orientation. I was surprised to hear that all these transaxels were developed not by Toyota. For some reason I was under impression that belt CVT is in too. The confusion is related to my test drive of gen 4 Prius. I asked about specific noise Prius transmission had made and Toyota rep said that this is belt friction noise in CVT. Regards, alex
Sounds like the Toyota rep was informed as car reviewers I like a belt would actually be quieter than gears directly meshing.
I didn't realise they were developed by other than TOYOTA (I thought I'd read partly in conjunction with AISIN-SEIKI which is essentially TOYOTA anyway). Did you read otherwise?
I think this company is behind this development. It is a big public company but I never heard about it. Wiki shows that Toyota owned 30% of it
