inline driveshaft motor?

[Christ]

Originally Posted by droptail

Trying to follow. Which end of the truck are you doing this mount, up front? And which direction are you driving, front axle or rear transfer case?

I'm speaking about removing the rear driveshaft and mounting the e-motor inline with it. You'll be driving the rear axle with both the gas engine and the e-motor, or just one or just the other, depending which way you want to run at a given point in time.

If you were to mount it as an input to the xfer case from the front axle's output, without it driving the front axle, you'd get nowhere, unless you're in 4wd Hi or Lo, which presents it's own particular set of problems, specifically the inability to shift on the fly (back into 2wd mode), the inability to exceed 45 MPH (not recommended in 4wd Hi, either), and the specifically shorter gear ratios assigned when in any 4wd mode.

Your e-motor would need to spin at a speed inverse to the output speed of the transfer case for a given vehicle speed in order to get you moving anywhere, and you'd still be doing it rather inefficiently.

Frankly, your truck doesn't make enough torque (as mentioned before) to worry about twisting the armatures of even smaller motors, so mounting it in line w/ the rear drive shaft is probably going to be the best feasible option for you, all things considered.

[droptail]

Originally Posted by roflwaffle

It'sa function of how engines operate. Engine efficiency, generally speaking, is relatively poor at lower loads, and tends to increase w/ higher loads. If the engine is making power, and we add power from an electric motor, then engine load will drop and efficiency will probably drop too. There are situations, depending on engine load/speed where engine efficiency won't drop much or at all, but especially at lower speeds, outside of when the vehicle is accelerating, using an electric will probably decrease engine efficiency.

On the flip side, since low load is where an engine operates inefficiently, and this corresponds to low power, w/ a manual trans and a sufficiently powerful motor/battery combo, we can run on just the electric motor's output and only use the engine where it's efficiency is maximized.

Course, like I mentioned before, this brings up another problem, namely stretching a motor's power output over whatever gearing the rear end has, and since optimizing engine efficiency tends to include taller gearing, we may end up having motor power peak at a speed much too high to be useful for low speed/low load operation. There are exceptions, for instance I have an old Mercedes that tops out at ~76mph or something, so peak power at ~38mph is fine, but for other vehicles with taller rear ends, especially larger ones, having peak power at ~50-70mph isn't desirable in the context of using a hybrid conversion in a cost efficient manner. Gearing the motor up would help, but that introduces another set of problems. If ya want specifics LMK.

Yes, and testing my combination of engine, gearing, mph, etc. will determine any improvements at a given speed.

My particular interest is electric motor only, low speed, stop and go, which will require gearing down an electric motor, and the ability to remove it from the drivetrain.

Thanks

[Christ]

In order to make it removable, you're going to want to have a second drive shaft fabbed up that will fit in place of the rear drive shaft, which couples the motor in with it.

If you already have a carrier bearing in your drive shaft, you can add a support right to that area that will allow you a mounting location for the e-motor.

If you don't, you'll need to make a frame-mounted cross member that you can install the e-motor to.

Drive shaft shops can make your new e-motor combination shaft for ~$100 if you provide the donor drive shaft. If they charge more than that, they're ripping you off. It's about an hour of welding and 20 mins of cutting and measuring.

[droptail]

Originally Posted by Christ

In order to make it removable, you're going to want to have a second drive shaft fabbed up that will fit in place of the rear drive shaft, which couples the motor in with it.

If you already have a carrier bearing in your drive shaft, you can add a support right to that area that will allow you a mounting location for the e-motor.

If you don't, you'll need to make a frame-mounted cross member that you can install the e-motor to.

Drive shaft shops can make your new e-motor combination shaft for ~$100 if you provide the donor drive shaft. If they charge more than that, they're ripping you off. It's about an hour of welding and 20 mins of cutting and measuring.

I didn't mean physically, I meant mechanically. I have to do this every time I drive the vehicle.
I have a more elegant solution in mind.

Thanks for the contribution.

Wish there were affordable large motors, and Lithium batteries.

[roflwaffle]

Originally Posted by droptail

Yes, and testing my combination of engine, gearing, mph, etc. will determine any improvements at a given speed.

My particular interest is electric motor only, low speed, stop and go, which will require gearing down an electric motor, and the ability to remove it from the drivetrain.

Thanks

Np! Ya don't have to test a setup to get a good idea as to how it'll perform. There's plenty of info available that can give you insight into how something will perform with a fair degree of accuracy.

[Clev]

Originally Posted by roflwaffle

Only if you use it. The bearings should be able to take high speeds, just make sure it isn't on or else it'll grenade.

Uh, no. The bearings aren't the limiting factor. At a minimum, you have to band the comm and properly balance it to use it at above its rated RPM.

[roflwaffle]

Originally Posted by Clev

Uh, no. The bearings aren't the limiting factor. At a minimum, you have to band the comm and properly balance it to use it at above its rated RPM.

I'm not talking about using it above it's rated rpm, just spinning it above it's rated rpm.

[Clev]

Originally Posted by roflwaffle

I'm not talking about using it above it's rated rpm, just spinning it above it's rated rpm.

Doesn't matter. At a minimum, the comm bars will lift, and at worst, the assembly won't have been balanced to handle the RPMs and will destroy itself. It happened to Mark Hastings on the EVDL in 2007, when the buyer of his truck towed it behind a car dolly with the transmission in first. The 9" motor and transmission both grenaded.

[roflwaffle]

Originally Posted by Clev

Doesn't matter. At a minimum, the comm bars will lift, and at worst, the assembly won't have been balanced to handle the RPMs and will destroy itself. It happened to Mark Hastings on the EVDL in 2007, when the buyer of his truck towed it behind a car dolly with the transmission in first. The 9" motor and transmission both grenaded.

Sure it does. There's a world of difference between doing 10k+ rpm, at or almost at twice it's rated speed, fast enough to grenade the transmission too, and doing similar given common 2nd gear ratios, with the motor at ~6k+ rpm, maybe ~10+% above it's maximum rated speed when powered.

[almightybmw]

So Christ, when you said it would present problems with being in 4HI, the OP is looking for a low speed electric only option, which with the xfer case in 4HI and the trans in neutral, this would drive the rear axle without problems. When he wants to go faster, slip the clutch, start the engine, disengage 4HI. I have an electric xfer case, and the motor does not need to be on for it to engage (although the vacuum actuated front diff does need the engine on).

Seems pretty cut and dry to me. Engage 4HI, shift to neutral, start the motor. Reach peak speed of motor, start engine, disengage 4HI, drive like normal. There really would be no limit on speed, only on the internal gearing of the electric motor, and the final drive ratio. No motor gearing? Example: My truck's final is 3.73, so that would be my electric motor ratio.