Very Mild Hybrid

[freebeard]

[citation needed] but if memory serves, the BMW R71 flatmotor twin went from flathead to OHV, was built under license in Russia -- and then in China were they added a reverse gear.

[cRiPpLe_rOoStEr]

AFAIK a reverse gear was already fitted in Russia too. In China it remained flathead until being recently replaced by a 650cc parallel-twin, and the shaft-drive also went away in favor of a chain...

[JSH]

Are you even allowed to do something like this? My understanding is that every car in Germany goes through TUV inspection every 2 years and any modification from stock needs to be from a certified company made for you vehicle.

I can't see TUV allowing you to replace the front brakes with hub motors or substantially increase the front track with spacers. I also don't see a way to put in an axle shaft for an inboard motor on the front suspension



However, the De Dion rear suspension has promise

If I was adding an electric motor to a Smart I would mount the electric motor to the De Dion tube inboard of the green arrow. Then mount a sprocket on the rear drive axle and connect the two with a motorcycle chain.

[freebeard]

http://www.edmunds.com/car-reviews/t...alkaround.html

That's the wackiest DeDion axle I've seen. Their Harry Miller example and the Dodge Route Van truck don't have the axle pinned in the middle. It acts as two trailing arms that are conjoined.

[Simon TT]

Originally Posted by JSH

Are you even allowed to do something like this? My understanding is that every car in Germany goes through TUV inspection every 2 years and any modification from stock needs to be from a certified company made for you vehicle.

I can't see TUV allowing you to replace the front brakes with hub motors or substantially increase the front track with spacers. I also don't see a way to put in an axle shaft for an inboard motor on the front suspension

TÜV only cares about safety, as of my understanding the Inspectors are personally liable for the safety of the cars the sign off, so they are really strict on some parts and don't care about others. You can drive with your entire interior removed but you basically can't deactivate airbags. Only certain parts have to get special certifications as an Example if you have halogen lights you can replace OEM bulbs with aftermarket bulbs that have a general certification for all vehicles, if you want retrofit Xenons you can use OEMs (if aviable) or Aftermarket parts that are certified for your specific model, but you also have to retrofit headlight washers.
On some parts you have to get an Einzelabnahme (individual approval) where you just have to show the inspector that the new parts are adequate, if you have a base model and want to change your brakes to the sporty model ones, your good to go, if you want to change them to some non OEM parts they test drive your car and decide wether they are adequate or not.

As for spacers, you are allowed to go to infinity and beyond as long as you can prove that your tires don't rub with the suspensions fully compressed turning from one side to the other, since my tires are quite inset and I plan on running the smallest legal tires (185 55 15"), when 225 45 17" fit no problem, this should be no problem

placing motors on the de dion beam seam quite simple, although I'd prefer them being on the front, because the can regen better there (more weight on the front during braking), it would be AWD and the weight distribution would be improved.

[Piotrsko]

Regen isn't affected by location since you are limited by low speed and tire traction

[freebeard]

....although I'd prefer them being on the front, because [reasons]

Don't limit your options to radial or axial flux:

duckduckgo.com/?q=transverse+flux+motor&ia=web

https://ietresearch.onlinelibrary.wi.../joe.2018.8184

Transverse flux machines as an alternative to radial flux machines in an in-wheel motor
Abstract
This paper considers the use of transverse flux machines (TFMs) as an alternative to radial flux machines (RFMs) in an in-wheel application for an electric vehicle.
[snip]
It is shown that the TFMs selected can deliver higher torques than the base motor during continuous operation, but have failed to deliver the required overload torque. Furthermore, low PF and low efficiency make these machines unsuitable[!] for the application of this in-wheel traction motor.

[JSH]

Originally Posted by Piotrsko

Regen isn't affected by location since you are limited by low speed and tire traction

Also helped by the Smart being rear-engine with a rear axle weight bias.

[Simon TT]

Originally Posted by Piotrsko

Regen isn't affected by location since you are limited by low speed and tire traction

yes and no

I probably won't reach the traction limit with regen braking, but I want to be able to use 100% of the regen before I use the friction brakes and 100% rear bias drives a LOT worse than 100% front bias, especially since the roadster is already light on the front axle which makes 100% rear brake bias even worse.

The Roadster is very light and has a short wheelbase so it is very agile/not very stable.

[JSH]

Something to consider when choosing between hub motors and frame mounted motors is the very large difference in axle torque.

With a hub motor the rated torque is also the axle torque. With a frame mounted motor the motor torque is multiplied by the gear reduction ratio which is generally 3 to 5 times.

A 100 Nm hub motor puts 100 Nm to the rear axle. A 100 Nm mid-drive motor puts 300 to 500 Nm to the rear axle.

That is why bicycles and motorcycles with hub motors are generally much slower to accelerate than a vehicle with the same size frame mounted motor.