E1PC Electric Race Bike

[caboteria]

That said, can someone 'splain to me why it needs a clutch reservoir?

They might have a transmission if they can't get the motor to spin fast enough for the speeds that they need to go (the Tesla has a 2-speed transmission).  The clutch would be pretty funny to use - you wouldn't use it for launches, just for gear changes.

'splain please.

I'll try, but I'm a software guy so it's been a long time since EE 101: An electric motor is a generator and a generator is a motor.  Both convert between electricity and work, just in different directions.  So if you put current into a motor it will generate torque, but if you put torque into a motor (like when you close the throttle at speed) it will generate current.  The problem is what to do with the current.  If you're really clever you can recover some of the current that you put into the motor when you had the throttle open, which makes the system much more efficient since you're not dumping energy into heat via friction.  The problem with this technique on a sportbike is that the drive happens at the rear wheel but the braking happens at the front wheel so you can't do too much.

Is there an EE in the house?

[Triple J]

Pretty cool...needs a windscreen though.

[jestor00]

Ahem, I'm sticking to my oil burning internal combustion engines thank you very much, why why why would you want a bike that purrs? I hate cats I need my bike to bark. 

[NAKID]

Instant tq, you're never out of your powerband...

[dbran1949]

They might have a transmission if they can't get the motor to spin fast enough for the speeds that they need to go (the Tesla has a 2-speed transmission).  The clutch would be pretty funny to use - you wouldn't use it for launches, just for gear changes.

I'll try, but I'm a software guy so it's been a long time since EE 101: An electric motor is a generator and a generator is a motor.  Both convert between electricity and work, just in different directions.  So if you put current into a motor it will generate torque, but if you put torque into a motor (like when you close the throttle at speed) it will generate current.  The problem is what to do with the current.  If you're really clever you can recover some of the current that you put into the motor when you had the throttle open, which makes the system much more efficient since you're not dumping energy into heat via friction.  The problem with this technique on a sportbike is that the drive happens at the rear wheel but the braking happens at the front wheel so you can't do too much.

Is there an EE in the house?

Not an EE but I play one on TV (physics actually)  You are right on, the only way to get engine braking would be to use the current generated by the motor under decel to recharge the batteries. The problem on a bike is that it would be likely lock up the rear wheel. On cars this isn't as much of a problem.

Understand that regeneration is not done by the brakes, brakes work the same converting the forward motion to heat. Regen works independently, just like engine braking.

check this

http://i.gizmodo.com/5151641/formula-1-cars-getting-electric-hyperspeed-jumps

[ryandalling]

check this

http://i.gizmodo.com/5151641/formula-1-cars-getting-electric-hyperspeed-jumps

That is so cool.

[Buckethead]

check this

http://i.gizmodo.com/5151641/formula-1-cars-getting-electric-hyperspeed-jumps

Video is down. Doesn't matter. Waaaaaaaaaaaaaaaaant.

[Drunken Monkey]

I'm not an EE either. I have a bachelor of arts... In Science!

But that description is spot on:

Basically you reverse the polarity on the connection from the battery to the motor and it goes from the battery running the motor to the motor recharging the battery.

One of the reasons Hybrids get better mileage in town than on the freeway.

Mind you, it's actually a lot more complex that that (they use brushless DC motors and complex controllers) but that's the principle.

Eventually, I predict two wheel drive electric motors with regen braking and traction control systems way more advanced than what we have now. It's a lot easier to do traction control when you're dealing with electric current then it is to do it controlling a throttle and/or hydraulic braking system.

[dbran1949]

Basically you reverse the polarity on the connection from the battery to the motor and it goes from the battery running the motor to the motor recharging the battery.

... the motor spins in the opposite direction 

[Drunken Monkey]

From wikipedia's article on regen braking:

For a given direction of travel, current flow through the motor armatures during braking will be opposite to that during motoring. Therefore, the motor exerts torque in a direction that is opposite from the rolling direction.

So... how is that not a simple reversal of polarity? 

Or is it more complex than that, and I'm missing something?

[dbran1949]

Current flow is not the same as polarity. Reversing the polarity is changing the positive to negative terminals (in a DC system) which makes the motor spin in the opposite direction. Current flow is determined by generation (source) vs. load (sink). In normal operation the batteries are the source and the motor the load. During decel (if the motor is still connected to the batteries and there is no diode or other electronic device to keep current from flowing "backward") the motor will feel a reverse EMF which resists rotation. All this happens without changing polarity which refers to the positive and negative wiring.

All in all an interesting subject and now that it is being used in F1 racing we ought to see some trickle down in a few years. It's a shame to be burning all the fuel to accelerate only to throw all that momentum away as heat on the deceleration.

One way would be to put a little generator in the front hub. It would free-wheel as long as there was no load on the output. When the throttle was backed off the tps could instruct the ecu to put a load on the output of the generator (recharge the battery). this way you could get some energy back without applying a braking force to the rear wheel

[dbran1949]

I know I am getting off topic here, but since the first link I put up had broken video, here is a better one

Ferrari F2009 KERS K.E.R.S. for dummies

[Pedro-bot]

Very Cool!!

Truly revolutionary.

[Pedro-bot]

Here it is in action


Motoczysz E1pc TTXGP racer first test at PIR

[bluemoco]

I'm not an EE either. I have a bachelor of arts... In Science!

But that description is spot on:

Basically you reverse the polarity on the connection from the battery to the motor and it goes from the battery running the motor to the motor recharging the battery.

One of the reasons Hybrids get better mileage in town than on the freeway.

Mind you, it's actually a lot more complex that that (they use brushless DC motors and complex controllers) but that's the principle.

Eventually, I predict two wheel drive electric motors with regen braking and traction control systems way more advanced than what we have now. It's a lot easier to do traction control when you're dealing with electric current then it is to do it controlling a throttle and/or hydraulic braking system.

I rode a Vectrix VX-1 electric scooter at an SAE meeting a couple of weeks ago.  The Vectrix electric scoots in stores today already have regenerative braking capabilities.

When you get the Vectrix up to speed, you can release the throttle to 'neutral' (closed throttle) position and coast.  If you want regen braking, you simply twist the throttle further 'forward'.  The further you twist the throttle 'forward', the more regen braking you get from the rear wheel.  The regen braking will slow the bike nicely, but there are also traditional braking discs at front+rear to add stopping power.  

The Vectrix scoots are pretty heavy (~450lbs, IIRC), so you can also use the 'regen' throttle to move the bike (slowly) in reverse!  Simply twist the throttle forward a little bit, and the bike will move backwards.  This requires a little rider caution, but it would come in handy if you're trying to back the heavy scoot out of a parking spot.

I was really impressed with the refinement of Vectrix' regen braking system.  The whole thing is very intuitive for anyone with riding experience.  Coincidentally, Vectrix has a patent on this throttle/regen control system for electric motos.