JohnK: Note that their first effort is NOT in primary traction motors, but in motors buried inside a transmission.

John K #79:

Good answer. I bet you’re on to something with the coolant oil, also.

As far as an electric car is concerned, simply the huge differences in AER of different drivers proves that during normally-needed accelerations, that period of normal acceleration demand is where improvements to electric motors would have absolutely huge payoffs as all EE’s know very well.

Since no-one drives at any time always on level ground at the peak motor efficiency speed in traffic that all goes the same speeds and our destinations are not exactly linear, then, incredible improvements to electric motor design can be accomplished without tremendous difficulties.

Here’s a consideration:
The range of gasoline fuel efficiencies between different driving preferences can cause as much as a 15% difference in achieved fuel efficiency in identical (or the same vehicle) ICE driving, due to the different ways acceleration is demanded.

A comparative example of energy efficiency:
The difference between the old two speed powerglide GM transmission of the Sixties, and the far more efficient six speed automatic with lockup torque converter of today, is huge. The difference may be somewhere between 15% and 20% overall, if not better.

Electric motors have to overcome the same inertial loads, and, even moreseo nowadays with increasingly congested “stop and go” traffic patterns. While we would certainly wish all efficiencies to be to the max, the great thing about progress is that it never stops.

Electric motors are the “new efficiency performance/better AER” focal point for all OEM’s going into electrification.

I really got stunned with that electric Datsun car race posted the other day! That’s the most awesome thing I’ve seen in years!

Imagine getting another 15% AER in a Volt?? That would be just awesome, because now you may be talking about a 46 mile AER!
That little motor improvement might cover as much as 60% of that last 22% of drivers who go more than 40 miles a day to work and back. There are also implications about a benifit towards lessening the charging loads to grid to a significant extent, and, certainly the timing of the charging. In addition, that improvement could shift the level of depth of discharge upwards so *VERY* positively-significantly, that the pack may have a commensurate positive shift in battery longevity overall.

LauraM: The sheer number of cars included in the recall is mind boggling

Had my Honda Cr-V in for a minor recall. While it was in there I had them change the front brake pads. They returned it with a smooth idle and good brakes.

Will be the same for Toyota. Although the recall looks bad at face value. They will be picking up a good deal of residual service income.

I expect the Volt to have a few as well. Will take 2 or 3 years of public use to expose them.

=D~

Although this article seems to talk about the 2-mode motors, GM also has a FWD 2-mode that they have developed. See slide 3 in this attached presentation.

http://www.che.ncsu.edu/ILEET/phevs/plug-in_2008/1A-1_GM%202-ModePHEV%20VUE.pdf

We know that this FWD 2-mode housing (or some facsimile thereof) is used in the Volt. However, to facilitate mass production, it is best to make large numbers of one part versus making moderate numbers of several parts.

Therefore, if you examine the specs for the Volt’s traction motor, it is 111 kW. Note that the FWD 2-mode has two (2) – 55 kW permanent magnet motors which are actively cooled. Combine two of these 55 kW motors, and you have essentially 111 kW. The generator is a 53 kW generator, so again, this motor will work.

So it is my speculation that the Volt has a total of three of these motors, similar to the one pictured above. Two work together as the traction motor, while the third is the generator. (Of course, the traction motor could be a unique part that is essentially twice as long as the one shown above).

As some have already mentioned, electric motors can have high efficiencies like 96%, but this is at full rated power. At low loads, they can be less than 80% efficient. Even at highway cruise speeds, the Volt only needs about 12-14 kW to cruise down the road. This is only about 12% of rated capacity!

One way to better this efficiency is to use two 55 kW motors mechanically linked together, but provide power to only one for lower load applications.