Hot-rodding the Toyota MGR

[e*clipse]

Some years ago I discovered the Toyota MGR, and thought "This has amazing potential for an electric vehicle drive."

The Toyota MGR is an integrated motor, gearbox, and differential that was originally designed for the rear drive of the Toyota Highlander Hybrid.

The sister-company Lexus, also made a version, the RX400h that was equipped with this rear differential.

The vehicles were available from 2006 to 2010, and the drives were also called "Q211" by Toyota, and can also be found by looking for "rear differential" and "rear differential carrier."

Ok, why bother?

1) They are a compact, powerful unit. They are rated at 50kW. (68hp)
2) Everything's included: Motor, gearbox, differential
3) All this weighs approximately 100lbs
4) It's possible to find used ones for less than $400, because no one knows what to do with them.

I'm starting this thread to provide as much information as I've been able to find on these motors. My intent is to actually get MORE than the rated power out of them, hense the "hot-rodding" name for the thread.

[e*clipse]

I purchased 3 of them and took one apart.

Here are some quickee specs from Toyota:
Type: Air/oil cooled permanent magnet
Power: 68hp (50kW) @ 4,600 - 5120 rpm
Torque: 96ft-lb (130 N-M) @ 0-610 rpm ( Don't know if that's motor or MGR data)
Max RPM: 10,500 rpm
Gear ratio: 6.860:1

Here are some pics to show what we're dealing with.

Gearbox side:


Front:


Resolver side:


Back:


Bottom:


Top:

[Cobb]

If this is what I think it is there was a discussion of using it on the insight forum not too long ago.

The problem was it uses 650 volts vs the 288 volts that the prius uses and in order to get that voltage you need a lot of damn batteries or some type of voltage doubler or tripler.

[cRiPpLe_rOoStEr]

What exactly are you considering to do? An all-electric conversion or some sort of hybrid setup?

Originally Posted by Cobb

The problem was it uses 650 volts vs the 288 volts that the prius uses and in order to get that voltage you need a lot of damn batteries or some type of voltage doubler or tripler.

Some hybrid trucks and buses have been fitted with a 650-volt setup nowadays, not impossible to source parts from.

[Cobb]

Theres a few guys on the insight forum who would love to talk to you.

Im guessing you can stack a few prius packs for the voltage, then you need a regulator or speed controller of some sort that isnt a basic carbon pile. Lastly use a few stacked mean well led power supplys to charge the prius packs and keep them in balance.

[MPaulHolmes]

I've got to get one of those. How do you attach it to the car? Are there only a few car types that would work for connecting it? Also, I forgot. Is the resolver signal only functioning while the 3 phases are getting their sine waves? Or was it eniugh just to manually rotate the shaft? And is there 3 lines that are sin(theta), cos(theta), and a neutral line that serves as the theta axis? So there is no 4th line that is the power supply for the resolver?

[e*clipse]

Yes, I'm familiar with the voltage they require.

If one uses NiMh cells; yes - it will require a LOT, because the voltage is less than half that of the Lithium cells I am using.

The controller is going to be orders of magnitude better than "a carbon pile" and it's being developed right here. http://ecomodder.com/forum/showthrea...ler-10839.html To make full use of this motor's capability requires knowledge of it's advanced magnetic structure. If one takes advantage of the amazing design Toyota did, then it's possible to make use of the reluctance torque to help fight the back-emf that starts to dominate at high rpm.

If I remember correctly, there was also a thread on DIYEV about using this motor. The conversion was a Saturn, and I think (I could be wrong here) he used a Prius sub-300V battery pack and a standard BLDC motor controller. To be perfectly honest, the author of that thread wasn't happy with the results. I definitely DO NOT want to diss on the author of that thread. He was doing ground-breaking work and was very innovative. If I could point out two reasons for his dissappointment 1) the vehicle was a bit heavy for a 50kW power source. 2) I doubt he got anywhere near 50kW, simply because the power source was supplying only half of what the motor was designed for.

While it **may** be possible to rewind this motor for lower voltages, I am not going that route. There are a number of extremely well-executed tests on these motors indicating the necessity of the high voltage. In addition, there is some excellent information from Toyota about this as well.

Here is a paper written by Munehiro Kamiya: "Development of Traction Drive Motors for the Toyota Hybrid System"
http://e-mobile.ch/pdf/2005/321.pdf
The paper details the power and efficiency advantages for increasing the voltage to 650V.

In addition, there are a mind-bending number of tests done by Oak Ridge National Labs on the various Toyota Hybrid systems. This is a perfect example of our government labs going all out with amazing results. For example:

REPORT ON TOYOTA/PRIUS MOTOR TORQUE
CAPABILITY, TORQUE PROPERTY, NO-LOAD BACK-EMF,
AND MECHANICAL LOSSES – REVISED MAY 2007
SciTech Connect: Report on Toyota/Prius Motor Torque Capability, Torque Property, No-Load Back EMF, and Mechanical Losses, Revised May 2007

EVALUATION OF THE 2010 TOYOTA PRIUS
HYBRID SYNERGY DRIVE SYSTEM
http://info.ornl.gov/sites/publicati...s/Pub26762.pdf

Reading a few of these publications leads one to the conclusion that Toyota might have a pretty good idea of what they are doing. While dropping the voltage significantly may reduce the amount of cells required, there are some very complelling reasons to use those scary-high voltages.

While I call this thread "hot-rodding" the MGR, I do NOT consider dropping the supply voltage significantly a method for improving the performance. It would be a bit like dropping the boost pressure on a turbocharged car and calling that a performance improvement.

Ok, to answer some questions about what I'M going to be doing with this.
1) They (yes, more than 1) are going to be the primary power source for an EV.
2) I am using a high voltage lithium pack to supply the power. The modules are from a Nissan Leaf, and so far I have a pack with over 400V. Boosting the pack to the full 600+V will require another 24 modules, which is not ridiculously expensive or heavy.

- E*clipse

[e*clipse]

Hi Paul!

Would you like to borrow one for testing?
Seriously, I think these are great little units, and I think the possibility of using Prius motors could open up with HUGE possibilities for the EV folks.

The MGR is bolted to the car with 4 bolts, two front, two rear. The threads and spacing makes no sense to me, I'll just give some dimensions later. Each output shaft has four bolts to connect it to a CVT. Again, I'll give some dimensions later.

The various versions of Toyota hybrids all use this type of resolver. The resolver's output is completely independent of the stator's signal. The resolver connector has 6 pins, 2 for the input signal, 2 for each pair of output signals.

Basically, a high frequency sinusoidal signal is injected into the resolver. I've messed with a bunch of different frequencies and waveforms. You can get away with a very NON-sinusoidal waveform if you're sloppy. The resolver's rotor is a semi-circular stack of disks that spin with the rotor. For this sytem, there are two lobes, but other resolvers may have four lobes. A device that looks a lot like the stator, just a lot smaller is used to inject and pick up the signals that are reflected back by the resolver's rotor. In essense, the resolver forms an envelope around the base signal, this envelope varies sinusoidally as the rotor rotates. There are two output signals, positioned 90 degrees apart. By comparing the magnitude and sign of the two signals, it is possible to figure out the rotational position of the rotor shaft.

Let me know if this helped or confused - I'd be happy to try again.

E*clipse

Originally Posted by MPaulHolmes

I've got to get one of those. How do you attach it to the car? Are there only a few car types that would work for connecting it? Also, I forgot. Is the resolver signal only functioning while the 3 phases are getting their sine waves? Or was it eniugh just to manually rotate the shaft? And is there 3 lines that are sin(theta), cos(theta), and a neutral line that serves as the theta axis? So there is no 4th line that is the power supply for the resolver?

[oil pan 4]

I have seen several of these at the scrap yard, some in pieces had no idea what they were until now.

[e*clipse]

Any chance you could find them again?

They tend to go on E*bay for about $300 > $600. You should be able to talk the scrap yard out of them for less.

Seems the power harness and connectors would be pretty good to have...

I'm going to see if my local scrapyard has any next week.

Originally Posted by oil pan 4

I have seen several of these at the scrap yard, some in pieces had no idea what they were until now.