I've been thinking about a project to add some E-motor power to the
rear-end of my formerly 4WD CRV. A mild hybrid?
With the rear differential deleted, those rear wheels are just sitting back there free-wheeling.. Doing nothing.
So, I've been wondering if there is any off-the-rack motor/controller that could be connected directly to a rear axial shaft to add a few HP of EV power to my old CRV?
This would be an ICE assist system and wouldn't need to run in total EV mode.
My goal would be to add 5 to 10 HP of power to the rear wheels while the car was at highway speeds, & have regen if possible..
From what I've seen of EV motor specs, low rpm (wheel speed) with good HP isn't possible.
I always thought that electric motors excelled at producing gobs of torque at low RPMs, allowing Forkenswift and the ElectroMetro to operate using only a couple of gears and no clutch.
Well I'm not 100% sure.. I think my tires are about 7' around and do 754 revs per mile.
So, a mile-a-minute would be 754 RPM on the end of that little shaft.
or, maybe even both shafts.
If you plan on driving both back wheels, you'll still need a differential back there, won't you? What happened to your rear diff?
I was thinking about that.. I've got a few ideas.
1. Drive one wheel. (Go around in circles?)
2. Install two motors, one for each wheel. (Small pancake motors, or shorten the shafts).
3. Reinstall the rear diff and good sized motor to drive it.
But that's going to take some extra HP to over-come Honda's fancy dual-pump clutch activator gizmo. Bigger motor etc.
The motor would connect to those 4 bolt holes in the upper left.
One crazy idea was to attach a motor to the transfer case output from the front end and drive the front wheels..
That's also a low RPM app.
video: M104.flv - Video - Photobucket - Video and Image Hosting
You can see the connection plate rotate as I push the V.
I wonder what the RPMs would be at 55 MPH..??
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Nothing happened the rear diff, I think it just needs some gaskets on the fill-n-drain bolts.
The reason I took it out was the propeller shaft was starting to go. The U-joints are starting to get stiff and notchy.
Too much trouble (& money) to repair or replace, when I don't really need 4WD.
It's a 1999, but only has about 33k on it, so the rear-diff hasn't much wear-n-tear at all.
I always thought that electric motors excelled at producing gobs of torque at low RPMs, allowing Forkenswift and the ElectroMetro to operate using only a couple of gears and no clutch.
But I've never built an EV.
I've never built one either, but about 10 years ago, I watched a co-worker put his EV together. I learned that building an EV is not an easy task. Something I would rather not try myself.
But, if I could convert my CRV into a mild hybrid for a reasonable cost, in time and money, that seems like a worthwhile goal.
I was just reading about the controller and other hardware used by Netgain
to convert ICE cars and trucks. http://www.go-ev.com/
And it seems pretty complicated at first glance.
mate up a cheap CVT from a scooter to the input of the diff. put the 5-10kw motor on the CVT. That way you get some torque multiplication at low speeds, but at high speeds when you want the motor to free-wheel, the CVT will gear the motor higher and reduce drag.
mate up a cheap CVT from a scooter to the input of the diff. put the 5-10kw motor on the CVT. That way you get some torque multiplication at low speeds, but at high speeds when you want the motor to free-wheel, the CVT will gear the motor higher and reduce drag.
I'm not sure a CVT or anything would be needed.
The Honda RT4WD system works kinda different. When the rear wheels turn,
they drive a pump(s?) and so does the propeller shaft from the transfer case up front. (The call it a Dual-Pump system).
If the front wheels start turning faster than the rears rear wheels,
(ice or mud) the difference in pump pressure engages the clutch,
allowing drive to the rear wheels..
So, all I would need to do to engage the rear wheels, is put some good
RPMs on the diff.. (Trick it into thinking the front wheels were spinning)..
I would rather not mess with that thing, since it's going to load up the wheels and it's heavy..
It would be a lot easier just to drive one wheel..
What would be the drawbacks to that?
Probably a bit off but my one suburban has a rearend differential from a completely different brand/model of vehicle.
It should be possible to put a rearend from a junkyard special "moderately" cheaply but you would need to figure out how to bracket it up and get it lined up.
There should be vehicles with less complex rearends that are approximately the right width for you particular application.
Okay, back to my Honda CRV:
Instead of hooking a motor up to the rear wheels, I'm wondering if I could hook up to the front wheels, using the output/input from the transfer case.?.
Get a nice motor, controller and four big 12V batteries.. Controller Kelly PM Regen 36-48 Volt 500 amp $387.00
Motor Mars ME-0708 PM Pancake 12-48 VDC Brushed $549.95
Here's a video of the axial shaft plate spinning (from the transfer case). M104.flv - Video URL -
I was looking at it today out in the driveway. I think it does about 3 turns for each rev of the wheels (or each 7 feet).
At 60 MPH, it will be turning about 2262 RPM. That seems to be right in the middle of the power curve for the Mars ME-0708 PM motor.. http://www.beepscom.com/v/vspfiles/a...me0708data.pdf
Direct connect:
The ICE-assist mode I'm thinking of, is to apply E-power to the transfer case manually as needed. (Going up a hill etc, or at 55 on a flat road).
When the ICE is off-line (clutch in or in neutral) the Mars motor would be
working alone. (Maybe good for going slightly down hill at 30 MPH).
My question is, when the battery is depleted and I'm on the ICE,
and that Mars motor is down there spinning at 2300 RPM, (not in regen),
is it going to be a problem? is it going to load down the engine very much?
Even if not current is being drawn off it??
Converting to a mild Hybrid has to be more difficult than this..?. Right?
