Hybrid Motorcycle - Replace Stator with Brushless?

A

Animalector

10 kW
Joined
Mar 17, 2012
Messages
976
Location
Mareeba - Queensland
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...
 
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...

images


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

[youtube]AMmdl77VOxg[/youtube]
 
Animalector said:
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...

images


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

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
 
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.
 
AmpEater said:
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.
Click to expand...

there is a permanent magnet on the rotor , no need to excite any coil .
its the usual type magnets , not nd .
 
So this stator/rotor is in the engine oil bath? Is it also used as the starter motor? Can you post the electrical schematic?
 
How are you going to drive the CDI? It gets power for ignition pulses from the stator.
 
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 .
 
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.
 
spinningmagnets said:
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.
Click to expand...

Sorry to high-jack this old topic, but I'm currently considering the exact same thing on a conversion project : https://endless-sphere.com/forums/viewtopic.php?f=12&t=114576 .

Do you recall where this was tried ? I'd be curious to know the details of how it turned out..

Thanks!
 
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