Add a second IMA motor for EV mode?

[Mike Dabrowski 2000]

While thinking about my e-wheel, and looking at the opened IMA motor on the same bench, I got an idea that has not been discussed.
How hard would it be to put a second IMA motor on the transmission side of the clutch.
It would require that the second motors rotor be tied to an extension of the transmission input shaft, and the clutch would still be required.

The stock IMA power electronics could be powered down, a big contactor switches the 3 phase drive wires to thesecond IMA EV motor, and a second relay switches hall effect sensors, then the IMA is powered up. Put in the clutch and use the MIMA joystick to control the car.

Of course it would be limited, but would provide a true EV mode.
If theory the ICE motor could even run occasionally charging the pack with the stock IMA motor/generator to extend the range?

[MN Driver]

Sounds like a good plan, would there be any reason why two motors would be needed though, if you could move the current motor to the other side of the clutch you wouldn't need to deal with switching. You would however have to defeat the clutch switch and start the car in neutral and autostop wouldn't be normal and might need to be disabled and FAS would be required instead which could be done and the engine could be bumpstarted instead with the car moving from MIMA or neutral started and then put into gear. ...or possibly a second MDM to avoid the switching while using two motors, wouldn't it require a contactor for each phase instead of one for all three? Do they make 3-phase contactors that can handle the current, how much phase current goes to the motor, isn't it more than the 100amps coming from the pack figuring lower voltage to the phases at low RPM?

[retepsnikrep]

Is there any chance of it actually fitting in the engine compartment with an extra motor?

I like the thoughts but both yours and MN's ideas sound pretty hard from an engineering POV.

[Mike Dabrowski 2000]

All good questions.
I do not expect to try this my self, but wanted to throw the idea out.
I just heard that the head x prize guy from WWU got a job at Tesla motors, so I don't think they will be coming out. Bummer!

When I pull the drive system out of the green insight, I will look at the fit, but expect that one could fit the extra 2-3" IMA motor in there with some tweaking.
Part of the big pile of 3 phase motor drivers from last week were quite a few big 3 phase contractors.

[IamIan]

Considering the other motors some people have squeezed into I1's engine bay ... I have no doubt it could fit ... but I share the suspicion others have posted about how much work might be involved.

Another thought ... if there would be two IMA motors ... you have ~100Nm of low end torque at ~1,000 RPMs ... with Peter's extra power work you have a potential ~150Nm of low end torque at ~1,000 RPMs ... the main reason to have a IMA motor separate from the ICE is to remove the air pumping losses of turning the ICE ... putting efficiency aside for just a moment ... that much low end torque ... still going through a transmission ... should be plenty of power to push the I1 around just fine even at low speeds even with the air pumping losses ... so aside from the efficiency hit, the second IMA motor could be mounted either side of the clutch ... at higher highway speeds the ~20kw or ~30kw limit would be the only time the ICE would be needed at all... and the I1 can maintain a good speed with just 20 to 30 kw .... or just as suggested a range extender.

If the ICE is just being used mainly as a range extender ... it could probably be down sized ... a 10 to 20 kw output should be enough for a range extender ICE ... that would give even more room to play with ... but is even more work.

oh well... just day dreaming I guess.

[Mike Dabrowski 2000]

I took a look at the fit, and it will not be easy.
There is a motor mount on each end of the motor/tranny.
The extra 2.5 inches of width, assuming one would only have to use the IMA motor width to make it work, would require two new motor mounts at a minimum, and they would likely have to be custom made.

[Hugh-Falls]

Originally Posted by Mike Dabrowski 2000

I took a look at the fit, and it will not be easy.
There is a motor mount on each end of the motor/tranny.
The extra 2.5 inches of width, assuming one would only have to use the IMA motor width to make it work, would require two new motor mounts at a minimum, and they would likely have to be custom made.

In addition to the second IMA motor length, somewhere in there you will have to find support for a bearing or two for that second IMA motor rotor and a shaft mount for an encoder disc.