Augmented "Hybrid" Design

Electric cars, trucks, ATVs, NEVs - things bigger than a motorcycle.
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modern_messiah   100 W

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Augmented "Hybrid" Design

Post by modern_messiah » Mar 01 2016 5:32am

Hi all,

I posted this on another forum, but this place seems to have a larger appetite for innovation so figure I should at least ask here as well :)

This is a potential project that for now is just an idea to flesh out a bit more rather than something I’d definitely do.

I have a FWD car that is also available in an AWD variant. Simply selling and upgrading to the AWD variant, while probably much easier, is not an option because it’s boring to me. Plus I’m an engineer and this sort of project would be insanely fun and satisfying to me.

My idea is to swap some parts between the two models to provide a way for me to interface electric motors with the rear wheels. The goal is not for fuel efficiency purposes; I simply want to help my car accelerate faster.

I am inquiring elsewhere about what suspension and drive-train componentry is required to be swapped between cars (should be direct swap and bolt on which is nice), however in essence the diff will be replaced by 2 electric motors which will interface with the rear axles. The battery pack and controllers will reside in the boot.

I am unsure about what sort of power figures I need, let alone the hardware to meet my requirements, so I’ll give a small break down of what I want the system to do and go from there:

> The car already does 0-100kmh (0-62mph) in approximately 6 seconds
> My plan is for the motors to assist with acceleration, but only when the cars main combustion engine is under 4500rpm and the throttle is at least 80% open.
> I’d also not expect the motors to be needed when the main drive train is running in gears 4, 5 and 6. The reason being that wheel slip will not be an issue at those speeds.
> Basically the rear motors are only running when I’m accelerating hard from a standstill or low initial speeds.
> All other times the motors are doing nothing apart from regenerative braking, which is only needed until the batteries are fully charged again.
> The battery pack can likely be quite small as well. Given the car is not reliant on these motors at all, a flat pack wouldn’t leave me stuck anywhere.

How I’ll get the motor controllers to function in the above manner is yet to be determined, but I can interface to my cars CANBUS via a Bluetooth dongle easily enough. I just need an intermediary device to read the CANBUS data and then automatically operate the controllers appropriately. Initially however I’ll simply have an electronic throttle controller mounted somewhere in the front of the car and worry about the automation later on.

I don’t need stupid power. Given the instant nature of the torque provided by electric motors, they tend to punch well above their apparent power rating. I’m thinking between 15 and 20kW per motor would make a noticeable difference. Those are peak ratings too as I’ll likely never run them flat out for more than a few seconds.

What are people’s thoughts? Brain dead stupid or something that would work, but more importantly be worthwhile?

If it’s the latter, what sort of motors should I be looking at? Matching controllers? Would gear reduction be necessary/recommended? What have I not thought of or stupidly overlooked? Why can’t/shouldn’t this be done?

I’m not even worrying about prices yet; as I said I’m just fleshing this idea out a bit more from the current “bored on the loo phase” lol.

Thanks for reading!

- Matt

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Grizzl-E   100 W

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Re: Augmented "Hybrid" Design

Post by Grizzl-E » Mar 02 2016 4:50pm

It depends are you an engineer or a machinist with an engineering degree and access to proper tools. If the former then don't bother. This would require so much custom fabrication and money it's a waste. If the latter then you will get lots of help here, but all of this stuff is huge money to go the route your talking. Minimum 20k investment.
Only brutal acceleration will do.

modern_messiah   100 W

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Re: Augmented

Post by modern_messiah » Mar 02 2016 5:17pm

Grizzl-E wrote:It depends are you an engineer or a machinist with an engineering degree and access to proper tools. If the former then don't bother. This would require so much custom fabrication and money it's a waste. If the latter then you will get lots of help here, but all of this stuff is huge money to go the route your talking. Minimum 20k investment.
Aerospace Avionics Engineer, but with access to proper tools and lots of friends in the machining world. I didn't think it'd be that expensive so it seems I have a fair bit of research to do before even seriously starting on this sort of project!
Last edited by modern_messiah on Mar 02 2016 6:07pm, edited 1 time in total.

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Grizzl-E   100 W

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Re: Augmented "Hybrid" Design

Post by Grizzl-E » Mar 02 2016 6:07pm

Hmmm well then you may be onto a neat project. But don't underestimate the cost. Good batteries and a couple motors alone will be 10k. Nothing's cheap at those power levels. You can make your own controllers to save cash but it's no small undertaking. Plus the weight will absolutely ruin your car.

Yikes Chalo, even engineers don't deserve that much grief :)
Only brutal acceleration will do.

modern_messiah   100 W

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Re: Augmented

Post by modern_messiah » Mar 02 2016 6:10pm

Grizzl-E wrote:Hmmm well then you may be onto a neat project. But don't underestimate the cost. Good batteries and a couple motors alone will be 10k. Nothing's cheap at those power levels. You can make your own controllers to save cash but it's no small undertaking. Plus the weight will absolutely ruin your car.
Yup, hence why I'm asking around first. The EV side of the costs are the killer, especially when I want two motors in order to avoid having to install a differential (which would definitely stop this in it's track). Maybe I should make my own motors as well lol. My car weighs 1400kg, the AWD version weighs 1515kg. Any additions over that 115kg difference would need to be powerful enough to be worth it.

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Grizzl-E   100 W

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Re: Augmented "Hybrid" Design

Post by Grizzl-E » Mar 02 2016 6:36pm

If this is your daily driver vehicle in my experience you will soon tire of experimenting with it. As for motors you really can't beat China. Sourcing the materials will be the same cost of the motors. Plus you can't beat those little old ladies at winding them lol!

As much as it sucks dealing with overseas manufactures, if you can find something off the shelf then it's so much cheaper.

Search on the forum for the few actual vehicle conversions that are mentioned.
Only brutal acceleration will do.

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kiwiev   10 kW

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Re: Augmented "Hybrid" Design

Post by kiwiev » Mar 07 2016 3:24am

Hi Matt

Sounds like a project :D

My Sonic 7 does sub 4 second 0 to 100 kph and no im not a jackass I did it ti prove electric isnt slow.

You are in luck Brett from Elmofo Newcastle has just completed a nissan GTR Awd hybrid search on Facebook it has an on demand 200 hp electric.

You really need to go AC but its all money $20k for motor controller and that again for a battery pack.

Cheers Kiwi

modern_messiah   100 W

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Re: Augmented "Hybrid" Design

Post by modern_messiah » Mar 07 2016 6:58am

kiwiev wrote:Hi Matt

Sounds like a project :D

My Sonic 7 does sub 4 second 0 to 100 kph and no im not a jackass I did it ti prove electric isnt slow.

You are in luck Brett from Elmofo Newcastle has just completed a nissan GTR Awd hybrid search on Facebook it has an on demand 200 hp electric.

You really need to go AC but its all money $20k for motor controller and that again for a battery pack.

Cheers Kiwi
Wow...I need to keep an eye on that GTR :twisted:

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bionicdan   1 kW

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Re: Augmented "Hybrid" Design

Post by bionicdan » Oct 01 2016 1:48pm

GEARS? Where we're going we dont need gears!

Due to metal plates and a body full of nuts and bolts I am as bionic as my bike. Mxus 4t 120v toshiba fets and 16ah 24s nanotech.

cycleops612   10 kW

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Re: Augmented "Hybrid" Design

Post by cycleops612 » Nov 23 2016 11:09am

We are at cross purposes philosophically (gofast - meh), but i love your idea of just raiding the parts bin of the awd version, and simply power the extra wheels electrically, discretely and therefore more simply.

I think most would say the truly magic thing about a ~prius is the low stress quiet, until the ICE kicks in at about 20kph or whatever.

That would be my focus. Electric assist to Get rolling, even if only to 5kph & then free wheels, using a really geared down modest electric motor.

5kw hub motors are cheap & cutting edge on alibaba in single units. Presumably, such 5 kw controllers also.

In this role, electric punches way above its weight. Max torque at ~zero rpm. 5kw is a lot.

Take inertial stress off the mechanical transmission.

Conversely, you could start with an AWD, and split the transmission so 2 wheels are electric drive.

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