GOBAO ECVT EMTB Mid-Drive Motor

[Diby2000]

In an earlier post, responding to @patdam I was conflating manual transmission as a gearbox (pinion or manual transmission in a car). Maybe not what was being asked. I now believe he was talking about derailleur transmission. My bad.

My thoughts are still that the e-cvt may be benifical here also as mentioned, the existing motor systems already have planetary and or belt speed reduction that is already contributing to some efficiency losses, here they could be the same or even less depending on which part of the planetary is being driven by the motor. The toyota e-cvt confguration is not the only possible configuration available. It has its own design constraints, such as an internal combustion engine that can only spin at a limited rpm, and in only 1 direction. I suggest that the 2 electric motors could drive the internal gears of the planetary (sun and planets) which will inherently provide significant reduction to the system.
Also, I can't remember which thread I mentioned this earlier, but the addition of a 2nd motor does not necessarily mean a loss of efficiency. It verry well could, and probably will/has is early generations of design, but these 2 motors are not both 1500w each, they will possibly be around 1000w and 500w. Remember the torque/power is added/multiplied through the gearing.

 

[Ndanger]

Not much more is required for ECVT besides connecting the extra motor and unshackling the ring gear to connect to the drive motor.

I am new to the concept of e-cvt and just coming to the conclusion that the chain ring rotates at a different cadence than the pedal crank. Interesting...

 

[Astro66]

I am new to the concept of e-cvt and just coming to the conclusion that the chain ring rotates at a different cadence than the pedal crank. Interesting...

This is why, if you set the E-CVT up with say 12 fixed gears. The pedalling should feel almost identical to a 12 speed derailleur, as it doesn't matter if the ratio change between the cranks and rear wheel, is done at the chainwheel, or the cassette.

It's only the ratio between the cranks and rear wheel that determines the feedback to your legs.

 

[jeanjean]

E2drive patents already show several potential ecvt configurations.

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Didn't yet check for gobao or avinox patents.

Edit:

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Nothing yet found for DJI or avinox

 

[jeanjean]

US20170217537A1 - Bicycle driving device - Google Patents

A bicycle driving device allows control to be executed in accordance with the riding conditions. The bicycle driving device includes a planetary mechanism, a first motor, a second motor, and an output part. The planetary mechanism includes an input body to which rotation of a crankshaft is...

patents.google.com

Shimano, 10 years ago, didn't believe in ecvt...

 

[patdam]

US20170217537A1 - Bicycle driving device - Google Patents

A bicycle driving device allows control to be executed in accordance with the riding conditions. The bicycle driving device includes a planetary mechanism, a first motor, a second motor, and an output part. The planetary mechanism includes an input body to which rotation of a crankshaft is...

patents.google.com

Shimano, 10 years ago, didn't believe in ecvt...

wy you said "shimano didn't believe", as they deposit patents on ECVT in 2017 ? (sorry i'm not fluent in english)

 

[jeanjean]

Well, they didn't bring it to the market.
Maybe they didn't believe that customers would buy this technology.
Maybe they had other reasons not to further develop this technology.

 

[patdam]

Well, they didn't bring it to the market.
Maybe they didn't believe that customers would buy this technology.
Maybe they had other reasons not to further develop this technology.

OK. . Perhaps it was also to block the market launch of this system, which would compete with them ?

 

[DylanJM]

Well, they didn't bring it to the market.
Maybe they didn't believe that customers would buy this technology.
Maybe they had other reasons not to further develop this technology.

10 years ago is a long time in the history of emtb. Remember what they looked like back then and what specs were? Development likely was not advanced enough to bring an eCVT to market back then.

 

[jeanjean]

Then it's time to take this project out of the drawer.
Customers are waiting

 

[Ndanger]

E2drive patents already show several potential ecvt configurations.

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Didn't yet check for gobao or avinox patents.

Edit:

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Nothing yet found for DJI or avinox

Excellent find!

 

[Ndanger]

I colored gears and put together the flow pattern along with a legend to try and better understand the design and the gear path to the chain ring (which is separate from the crank) as attached. Green is the gear reduction, similar to a derailleur bike, everthing else is the transmission that will effectively replace the derailleur drive train.

 

[slickrock]

I colored gears and put together the flow pattern along with a legend to try and better understand the design and the gear path to the chain ring (which is separate from the crank) as attached. Green is the gear reduction, similar to a derailleur bike, everthing else is the transmission that will effectively replace the derailleur drive train.


View attachment 187821

I colored gears and put together the flow pattern along with a legend to try and better understand the design and the gear path to the chain ring (which is separate from the crank) as attached. Green is the gear reduction, similar to a derailleur bike, everthing else is the transmission that will effectively replace the derailleur drive train.


View attachment 187821

Look at the mechanical extra design required to get power to the chainring that is axial to the pedal axle. If that was relaxed, the design would even be simpler.

 

[slickrock]

I honestly don't know.
There are less moving parts, less gear teeth interactions (more teeth that are actually transmitting torque and this is where most efficientcy losses happen, but less overall), maybe less rotating inertia? In the single planetary gearbox, but you also have 2 electric motors that the manual gearbox does not have.
I think this is not so straight forward a question/statement.

I think more relevant is:
Is a single large powerful motor with a chain and deralleur more efficient than an ecvt and chain/belt/whatever drive system you use to get the power to the rear wheel?
If so, what is the deference and do you think this trade-off is worth the potential benifits of the system?

We will see how multiple ECVTs motor solutions flesh out (don't forget 2025's E2's ECVT, which BTW has been suspiciously silent after the Gabao/Avinox announcements), but my feeling is that for the whole EMTB system (including the rider), ECVT may be actually more efficient that a typical motor/derailleur setup in use, in pretty much in an analogous way Hybrid drive makes HEV cars get better mileage ICE cars:

1. ECVT can keep the motor in its most efficient band of RPM, changing gear ratios to balance torque and cadence, ultimately giving you more range. This is better than typical EMTB eco modes which run the motor at reduced torque or kick in after a lot of pedal torque is applied.
2. ECVT can keep the rider in his/her most efficient band of power delivery. By choosing a consistent pedal cadence/pedal torque balance, you can best convert those calories into forward momentum.
3. Current EMTBs, especially the new powerful ones like the M2, allow people to over drive the motor and over torque the system rather than being in the correct gear to keep drivetrain from blowing up. ECVT puts you in the best gear to keep this from destructive energy loss from happening.
4. Mechanical derailleur changes, gear jumping, cross chaining and other shifting latencies alone add inefficiencies and are more frustrated when the elements/mud come into the picture.
5. AI Greg mentions torque slip with ECVT, but there is gear slip with legacy setups.
6. And finally, battery regen capability. Though this will be harder to implement with current proposed bike designs.

Keep in mind that ECVT can still be put into a mode that puts the motor in its optimum power curve rather than its optimum efficiency curve, so your boost mode can ditch the efficiency mode mode when needed. There's really a ton of flexibility to had with ECVT.

 

[Fangs2k]

ECVT may be actually more efficient that a typical motor/derailleur setup in use, in pretty much in an analogous way Hybrid drive makes HEV cars get better mileage ICE cars:

I’m not sure that’s a very helpful comparison.

Electric motors in ICE cars (hybrids) help with mpg as they’re ’fuel multipliers’, they assist with the hard work to get a car moving for example, a very energy intensive phase in driving.

For e-bikes, the engine is the human, the electric motor is the multiplier and that helps with the energy intensive parts of cycling (uphill etc).

Will an ECVT be more efficient than an equivalent motor and derailleur setup? We don’t know yet, but the basic laws of physics will still apply so I predict you’ll be able to throw a blanket over them.

There are lots of good reasons for ECVTs on EMTBs, not sure efficiency will be the main one.

 

[Red Peekay]

This a short cool video on the concept bikes looking at this motor..

36K views · 543 reactions | Avinox présente aujourd’hui 4 concepts équipés de son prototype de moteur MG Concept, un moteur intégrant une transmission. Pour l’heure, peu d’infos sur ces 4 cadres qui sont eux aussi encore à l’état de prototype. | En

Avinox présente aujourd’hui 4 concepts équipés de son prototype de moteur MG Concept, un moteur intégrant une transmission. Pour l’heure, peu d’infos sur ces 4 cadres qui sont eux aussi encore à...

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