eCVT

[12p3phPMDC]

Sounds like you have a good grasp of it all to me Amberwolf....

albeit, I'm still learning too...so I am definitely no expert.

What kind of motor would you nest inside the F&P motor? another smaller outrunner?

The complexities of reverse and the super high torque modes with the ring gear and sun gear spinning in opposite directions makes
me squirm a bit.

I think that you bring up some good points in regards to "idle" modes and current draw. I think that you can avoid huge stall currents at low rpm
by playing some tricks with the controllers. You would need a dead band possibly around low rpms where you would benefit from
reversing one motor and having the other in a forward direction to give you "crawl" gear. Then as you speed up, the other motor
would need to quickly change directions and go to a fast enough forward direction to avoid the dead band zone.

That's why I want to put some one ways in....to isolate the inputs, and to add redundant operation.
In a hybrid app, you could run the ring gear off a honda mini 4 stroke input and run the sun gear off the BLDC.
That gives you full "OR" operation, 1 or the other or both.

Then you have redundant operation via freewheels or oneways for the outputs too...You could have a tri-brid, Human Power, Electric, and Gas.
The one-ways mess with your ability to regen, but oh, well. you can't have it all unless you work at Toyota or Ford R&D
with the hybrid synergy drives. Hell, maybe we can figure it out?

I also think that there is a great potential for a Prius like hybrid drive here. It's pretty cool how the Prius uses two MGs (motor generators)
and an ICE. I think that they Prius has 7 possible modes of operation.. It doesn't have a dedicated starter...it uses one of the MGs to
start the ICE through the planetary....which is cool IMO.

This is from memory, I'll try to visit the prius sites and touch up my memory...

MG2 (Ring Gear drive coupled to differential)
ICE (tied to planet carrier)
MG1 (sun gear)

1. Full Speed Ahead, All three prime movers are contributing to forward motion and torque
2. MG2 only
3. MG2 and ICE providing forward torque
4. MG2 and ICE with MG1 generating
5. MG2 regen and MG1 regen
6. MG2 and MG1 full torque
7. Reverse

[Miles]

In the No-Hassel system, the speeds of the two motors are controlled automatically:

This is an overview of the control logic of the Nohassel propulsion unit´s two motors

The functionality of the two motors is controlled electronically. The basic function is quite logical and can be described as this control loop:


A) set the most powerful motor (LRK) to a speed that is within range of epicyclic gearing for the wheel RPM and optimized for LRK efficiency
B) set the speed of the smaller motor (HS) to a speed that matches LRK and wheel RPM (taken from a premade table in the master controllers program memory)
C) check if wheel speed is correct (based on sensor input from pedelec, brakes, throttle, current sensors, temperature sensors)
D) adjust target speed if needed based on input from C) and goto A)

[amberwolf]

Why don't you download the trial version of Alibre? You can continue to use it (with a limited number of parts) after the trial ends. Another alternative is the free version of One-Space-Modeller: http://www.ptc.com/offers/tryout/pe2.htm

Thanks! I will try both of them and see what they offer, and how intuitive their GUIs are (very important).

What kind of motor would you nest inside the F&P motor? another smaller outrunner?

Yes. Probably a rewound cieling fan motor, as they come in a range of small sizes and I happen to have a few.

The complexities of reverse and the super high torque modes with the ring gear and sun gear spinning in opposite directions makes me squirm a bit.

I don't really understand it enough to be squirming yet. After I play with ideas more I will probably begin to understand enough to get concerned. More likely I will have to break a prototype to grasp the problems.

I think that you bring up some good points in regards to "idle" modes and current draw. I think that you can avoid huge stall currents at low rpm by playing some tricks with the controllers. You would need a dead band possibly around low rpms where you would benefit from reversing one motor and having the other in a forward direction to give you "crawl" gear. Then as you speed up, the other motor would need to quickly change directions and go to a fast enough forward direction to avoid the dead band zone.

If I understand what you're saying, it seems easier to just keep them at higher RPM for the low-speed output, since it seems to me like the motors I've used so far (brushed) take less power at higher speeds (not including riding against wind resistance) than they do at lower speeds, given doing the same work. They don't get as hot, either.

That's why I want to put some one ways in....to isolate the inputs, and to add redundant operation.

I don't want to use anything like that because I'd like to have it capable of regen.

In a hybrid app, you could run the ring gear off a honda mini 4 stroke input and run the sun gear off the BLDC.
Then you have redundant operation via freewheels or oneways. Then you could have a tri-brid, Human Power, Electric, and Gas.

Interesting....

The one-ways mess with your ability to regen, but oh, well. you can't have it all unless you work at Toyota or Ford R&D
with the hybrid synergy drives.

Maybe use something like dog clutches to engage or disengage the drive of each input; then you could freewheel or regen, in any combination?


Regarding the Prius stuff, I don't pretend to understand how more than two inputs works. I haven't figured out a way to wrap my brain around it yet. It *sounds* great, but I just don't "get" it yet. I'll figure it out evnetually.

[12p3phPMDC]

What happened to the rest of your post Miles....?

I was trying to quote it...yikes...The fastest moderator on that side of the Atlantic strikes again....

So, as far as the NoHassel controller goes, it basically mixes the motor torques automatically to avoid
spinning the other side backwards...i.e. when torque is put on the ring gear and there is large intertia on the carrier (i.e. my bike and weight),
the sun wants to rotate backwards. For the design, I'm proposing, the freewheel would prevent that. For NoHassel and Solomon,
the motors would push back via control algorithms.

Its the special cases that were in your unedited post that mess with me......
I think two freewheels help to simplify these problems for me anyway...
You still may need really good starting torque from either motor if one motor is running and preventing the other
from starting due to back driven torque from the sun gear (or riing). This may require sensored solutions.
If you are feeding the planetary with reductions,it seems that the reductions will reduce the back drive torque at the motor.

I don't claim to understand all the Prius modes, I just know they exist.

[Miles]

What happened to the rest of your post Miles....?

Sorry..... It's all in the FAQ: http://groups.google.com/group/nohassel ... -questions

[amberwolf]

Well, it looks like while the type of unit I wanted to make (based on the Solomon unit) might be a *form* of IVT, it does not actually allow for different ratios for torque conversion. Meaning, it is indeed a variable-speed unit, but it is not variable-torque, in any traditional way.

Whatever the torque input is from the motors will be summed and presented at the output. So you'd still need high-torque motors on either end of the shaft (the sun and ring gears), to get good torque out of the planet carrier.

It does still allow you to spin both motors at very high speeds while keeping the output shaft at a very low speed, but that's all. I guess it would really be only good for if you had two motors that were half the torque you needed, you could connect them both with this device and drive one output. But there are other methods to do that.

Here's the original thread with the info, on DIYEC. Link starts at end of relevant part of thread, you can read upward from there if you want to see how the discussion reached that point.
http://www.diyelectriccar.com/forums/sh ... post164318

Also crossposted this to the other IVT thread.

[12p3phPMDC]

Amberwolf,

I think you bring up an excellent point here.

There is no dynamic gear ratio with this kind of system, only summing of torque from dynamic sources.

If you combine a planetary and a CVT, you can arrive at an IVT with one prime mover

http://cvt.com.sapo.pt/ivt/ivt.htm

Its pretty cool all different forms these things can take.

[Miles]

More split-torque technology:
http://nexxtdrive.com/

Specifically:

[Miles]

Article in AtoB on what has subsequently become NexxtDrive technology:
http://www.atob.org.uk/electric-bikes/e ... nsmission/

[Jeremy Harris]

That looks perilously close to the Toyota HSD principle to me, in fact so close that I'd be inclined to think that it might infringe on some of Toyota's patent claims.

[Miles]

That's an old article from AtoB magazine August 2005. I just noticed that it was now available online.

As he has his own patents (see above), I guess that's covered.

See also: http://www.bike-eu.com/Home/General/201 ... IK003881W/

[Miles]

Split torque CVT with only 1 input...

http://www.torqueunlimited.biz/

[crossbreak]

nice finds! the next drive looks quite interesting, but I doubt it would be more efficient than a NuVinci. The losses of the electric path are not negligible

Did you know the Prius driving simulator? The bar diagram is a good tool to visualize the speed ratios at different speeds and driving resistances. Sadly the prius simulator does not support hills

http://www.wind.sannet.ne.jp/m_matsu/pr ... _i18n.html