[drummerian]

Hey guys,

I am new around here but have been admiring some of the creations on here for some time now!

As a car nut (with a passion for the classic mini) I was lucky to be allowed to attempt a university project for my electronics degree in the vain of an electric car. This project is going to be fully published online and we will be attempting to use the platform to research various electric car challenges.

My main part of the project is going to be the drive system, with other students working on battery systems (with the possibility of Power Capacitors).

For the drive system I hope to retain the Minis original front subframe, taking out the engine and fitting in a Motor 'cage'. What i ideally hope to achieve is independent drive of the front wheels, using a motor to drive each wheel. Custom driveshafts would be made up for this.

This is where I need some help. As far as i know, many conversions use the original cars differential and sometimes the gearbox to drive the wheels. My main concept (remember this is a research platform) is to have the independent motor controllers for each wheel driven by a microprocessor. This would allow for differential control (with both limited slip, std, and locked out) options and launch control.

I fully believe this can be done, I am just wondering if anyone has attempted similar before?

Any advice would be much appreciated.

Thanks

Ian

 

[MalcolmB]

That's a nice project you've chosen. It's good to know my income tax is going towards something useful

I've come across several references to independent control systems like this, but mostly research or corporate R&D projects without any great detail. I haven't come across any DIY projects.
Here's a paper you might find relevant: http://www.evs24.org/wevajournal/php/download.php?f=vol3/WEVJ3-200394.pdf

Are you planning to build the controllers yourself, or just modify existing controllers?

I'm busy collecting parts to convert a classic mini myself. I'm also using a pair of motors to drive the front wheels independently, but I'll be keeping things simple and running them in series, or possibly with individual controllers and a single throttle input (not decided yet).

 

[Alexander_B]

your idea is sound, but your first "problem" would be finding a type of electric motor that:
- has sufficient torque. multiply the standard torque spec. of the mini engine by 2.5, thats about what you need per motor. (most cars have about a 1:5 total reduction in first gear)
- has a usable rpm range of about 0 to 1500. (or, take desired top speed divided by wheel circumfence to find needed rpm, take a fair margin of about 20-30+% extra, most of this is 'lost' due to motor rpm sag under load compared to unloaded max rpm.
- is narrow enough to be "stacked" back to back and have drive shafts to the wheels.

that, or use a motor with less torque, more rpm, and a non-inline reduction (IE. belt drive or gearbox) 'face to face' or asymetrically stacked side by side so you have more room for the driveshafts as well.

 

[drivin98]

The three I know are all in Britain and use independent motors to drive the back wheels.

One is the so-called "wind car" by Dale Vince.
Another is the RGE Endurance electric Radical that uses Evo Electric motors that have been slightly "de-tuned" so as to make them more durable for the Pan American highway trip.
Finally, there is the Westfield iRacer that uses a pair of Oxford YASA motors.

 

[dtbaker]

these guys
http://www.ampelectricvehicles.com/

look to be doing something similar, and the package they've picked for the sports cars might work for the mini.

 

[marcexec]

Hi,

We have a classic Mini ourselves.

If you are looking for compact motors, take a look at Agni.

They are (AFAIK) mostly used in motorcycles due to the efficiency and power-to-weight ratio.

taking the 50 lb/ft = 67Nm from a 998 A+ engine, I found
http://www.agnimotors.com/135_Series_Performance_Graphs.pdf
putting out 35Nm per motor.

All this depends on your application of course (endurance, drag, daily, whatever), so tell us more!

Welcome, BTW!

 

[drummerian]

Hey guys,

Thanks for all the great replies so far, alot of ideas i have thought about and some new ones in there too!

I am still keen on doing direct drive of the two front motors, however, may use belts to drive the driveshafts in order to make motor selection easier...and mounting!
Can also look into a gearbox on the end of the motor, but this may be more difficult to mount the motors back to back.

Won't be making custom controllers this year as we don't have a large amount of time. What type of controllers are popular at the moment so i can have a look?

The artical that was linked is very impressive and illustrates a few ideas i have had of using current sensors to aid in motor control. My design will hopefully incorporate some of the ideas used into a front wheel drive version with independent wheels rather than front rear.

If anyone has any other ideas please post up! The idea is to make this project fully documented online for others to attempt! Especially need some ideas on controllers so that i can start to define the motors and battery voltages to run at!

IAn