Hybrid Motorcycle - Replace Stator with Brushless?

General Discussion about large electric scooters and motorcycles and other things with no pedals.
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Animalector   10 kW

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Hybrid Motorcycle - Replace Stator with Brushless?

Post by Animalector » Feb 18 2016 10:23pm

Hey all,

just wondering if it is practical to replace the stator on a IC motorcycle with a BLDC motor.. It seems to me like the stator is about the same size as some of these small(ish) motors capable of peaking at 10(ish) kW

I was thinking it would be really cool to pull off the existing stator, attach a RV160 short or something (5 - 10kw in power) and bolt it onto something small like this:
https://en.wikipedia.org/wiki/Honda_CBR125R

The idea would be to create a hybrid motorcycle, keep the battery quite small, for regenerative braking and acceleration assist. an RV160 on a CBR125 motorbike would double it's power for acceleration,

Challenges:
  • we'd have to come up with a DC/DC converter to charge the existing 12V lighting and starter system but that should be easy, it's just a DC/DC converter into the existing 12V battery. Though, we'd have to run the system at very light regen constantly to avoid discharging the existing 12V battery (or will general braking cover this scenario??)
  • physical mounting considerations (new housing or stator cover.) is it possible to attach to existing shaft? I would think so?
  • interface between existing throttle / brake for power control and braking
  • (for the above point simple solution could be at 3/4 - full throttle twist it just provides max electric assist, so it's like an instant 10kw boost only if you'r accelerating hard... or just linear control somehow
  • braking could be a pressure sensor, to provide variable braking input varying with hydraulic pressure... to match the feel of the current braking system. this is engine braking only, so having the clutch in won't help.... it'll just stall the motor
  • battery size and location and capacity (I'm thinking 48V, 10Ah Lipo or 18650), this will be quite small, light, electronically limit consumption to 5Ah to improve longevity.
  • controller only for boost / regen applications so it can be physically small due to not requiring extended heavy load.
  • bolt on solution (somewhat) to a very *VERY* common bike design
  • simplified ADR compliance considering it is not exclusively EV powered.
There's a cheap $1200 Honda CBR125 that I want to buy and I think it'd be a fun project.

floor open for discussion...

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amberwolf   100 GW

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by amberwolf » Feb 19 2016 3:34am

What "stator" are you referring to? Where is the motor it is part of, in relation to the drivetrain of the bike?

Animalector   10 kW

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by Animalector » Feb 19 2016 5:02am

Oh sorry. I'm taking about the electric generator / stator big round coil thing usually on the left side of the motor opposite the clutch which is on the right side, it is hanging off the side of the crank shaft I believe... I'd put up a picture but I'm on my phone...

Image

Like that. Do that whole side off and plonk a bldc motor there not all motor have those gears there

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by Drunkskunk » Feb 19 2016 11:37am

In principle, sounds like a good idea. Wrong motor, though.
The RV160 is much bigger than the stator, or even the cover for the stator of a Honda. it would also stick far out to the side of the engine. It's also totally the wrong RPM. the RV160 has a voltage range of up to 96v, and a KV of 45. that means you would kit the limit at just 4320RPM. that's not even into the Honda's powerband yet. You need an electric motor that can handle 12,000 RPM at reasonable voltages.
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Animalector   10 kW

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by Animalector » Feb 19 2016 3:41pm

Hmm. Good point though it's probably down low where you would want the assist... But yes I see the point.

I don't think it matters of it sticks it a bit and you likely wouldn't need to put the cover back on.

So what motor? Something with a kv around 150.

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by spinningmagnets » Feb 19 2016 3:51pm

There was one project that removed the cylinders, head, and pistons/connecting rods. It left the crankshaft and the added electric motor drove the timing chain that normally attached from the crank to the overhead-cam.

The main purpose was to have a fast, cheap and easy way to convert an ICE to electric, and give the motor the use of the gears. After the conversion, that particular builder ended up using only two of the six gears in the stock transmission.

I have no experience with that.

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by gogo » Feb 19 2016 9:25pm

To double the torque/HP, you'd probably need the crank interface to look like the one on the drive gear side. A woodruff key and tapered shaft isn't going to cut it. The crank and the rest of the drivetrain probably won't take 2X either.
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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by Animalector » Feb 19 2016 10:08pm

Fair enough. So long story short... Mechanically not strong enough. Even a 5kw boost would be cool though. I wonder what power it could handle?

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gogo   10 MW

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by gogo » Feb 19 2016 10:21pm

I'm hip to the augmentation idea. It would be a great implementation for getting a single speed moped launched, and similar to the Koenigsegg Regera drivetrain.

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by sss » Mar 06 2016 11:31am

Animalector wrote:Oh sorry. I'm taking about the electric generator / stator big round coil thing usually on the left side of the motor opposite the clutch which is on the right side, it is hanging off the side of the crank shaft I believe... I'd put up a picture but I'm on my phone...

Image

Like that. Do that whole side off and plonk a bldc motor there not all motor have those gears there
the stator on the motorcycle is already "brushless" . the only thing you need to do is to rewind the stator , and use better rotor with neodymium magnets .

i was planning similar idea , but main thing i wanted is to combine the generator and starter into one single motor that will works as a starter , generator and power booster .
unfortunately this can work on a built from scratch motor much better then modifying existing ice

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by AmpEater » Mar 06 2016 8:32pm

I second just re-using the stator.

It's already mounted, it fits the space, and it's not a whole lot different than a brushless motor.

They make permanent magnet upgrades for them. You'll want to do that.

Then you'll need to rewind it for your chosen voltage. Next comes a 3-phase speed controller. You could add hall effect sensors, or go sensor-less.

You could probably try it out right now with 2 cheap ESCs from hobbyking, one for the stator and a second brushed ESC to excite field coil. It will work as a proof of concept perhaps.

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by sss » Mar 07 2016 10:14am

AmpEater wrote:I second just re-using the stator.

It's already mounted, it fits the space, and it's not a whole lot different than a brushless motor.

They make permanent magnet upgrades for them. You'll want to do that.

Then you'll need to rewind it for your chosen voltage. Next comes a 3-phase speed controller. You could add hall effect sensors, or go sensor-less.

You could probably try it out right now with 2 cheap ESCs from hobbyking, one for the stator and a second brushed ESC to excite field coil. It will work as a proof of concept perhaps.
there is a permanent magnet on the rotor , no need to excite any coil .
its the usual type magnets , not nd .

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gogo   10 MW

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by gogo » Mar 07 2016 10:24am

So this stator/rotor is in the engine oil bath? Is it also used as the starter motor? Can you post the electrical schematic?
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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by KLRbee » Mar 07 2016 1:13pm

How are you going to drive the CDI? It gets power for ignition pulses from the stator.

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by sss » Mar 07 2016 1:33pm

stator is in oil bath most of the time , it helps with cooling .
no , its not used as starter (i want to try and do so) same as modern cars use moth starter motor and an alternator .

KLRbee:
you are right that smaller bikes get the timing signal from the stator for the cdi .
but on modern multi cylinder bigger bikes not so . they use separate pick up device and camshaft position sensors .

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Re: Hybrid Motorcycle - Replace Stator with Brushless?

Post by KLRbee » Mar 07 2016 6:44pm

The original poster was mentioning a CBR125 which almost certainly uses a total loss system. So perhaps adding something to the drive chain would make the most sense, since a stator replacement would also need to replace the ignition system.

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