P112 Prius Gen2 Transaxle
I present to you the P112 transaxle, the latest in hybrid vehicle technology, if it were the mid 2000s. In this 100kg package we have a bell housing, which is the interface which connects to the ICE; 2 electric AC motors, one that is 50kw and another that is around 30kw; as well as the necessary gear systems, electrical and mechanical interfaces. With some clever welding of part of the power split device, we can cause both MG1 and MG2 to spin at the same speed.
Those wanting to learn more about this transaxle should watch this video: https://youtu.be/ia6jJO3cuOY
The current implementation for the Damien Maguire control board for the inverter only allows use of MG2 for propelling the vehicle, and uses MG1 for charging. An earlier board version did in fact control both motors but this function has since been removed. I may custom order my own board of the older version so that I can gain use of both motors as that will mean a combined power of ~80kw and 500nm+.
The rotational maximum speed of MG2 is rated at 6500rpm. The original vehicles maximum allowed speed was 103mph and at this speed MG2 is running at ~5700rpm. MG1 is rated at 10000rpm which means I have a bit of headroom to work with, not to mention I’ll never get to 103mph ever on the roads. This gives me piece of mind knowing this hardware can work as hard as I need it to.
I believe this transaxle has an oil pump built into the end of the outer housing for MG2, which is also a 3phase AC motor. This has a connection directly into the inverter which means that cooling for this can be easily done. To simplify things I will probably just use a 12v pump as that will make things cheaper. This transaxle, along with the inverter, require cooling as there is very little thermal mass given to cooling. I will be ensuring to build a robust thermal solution once installed in the vehicle.
In the coming weeks I do plan on opening this thing up and giving it a clean and making sure everything inside is as should be. There is also an AC compressor that I need to remove and decide if I want to use it. There is currently a small effort trying to reverse engineer this specific compressor for DIY use.
Here are a few photos, more coming in days to come:
If anyone has any questions ask away. Inverter is also on its way. That writeup should be more detailed regarding the underlying tech of running these motors