Go Back   EcoModder Forum > EcoModding > Fossil Fuel Free
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-28-2016, 12:43 AM   #11 (permalink)
Master EcoModder
 
Join Date: Aug 2010
Location: Philippines
Posts: 2,173
Thanks: 1,739
Thanked 589 Times in 401 Posts
Quote:
Originally Posted by RedDevil View Post
I read about this project.
IIRC they found they could accelerate faster by carefully controlling the speed of the wheels to some precalculated rate rather than relying on traditional traction control, so they could operate on the limit all the time.
TC would take it slightly over the limit, then fall back behind to regain the correct speed.
That makes a whole lot of sense.

And with the electric motors, they can control the exact rate of wheelspin, so even if they lose traction, they still get linear acceleration.

  Reply With Quote
The Following User Says Thank You to niky For This Useful Post:
RedDevil (06-28-2016)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-28-2016, 03:12 AM   #12 (permalink)
Permanent Apprentice
 
Join Date: Jul 2010
Location: norcal oosae
Posts: 523
Thanks: 351
Thanked 314 Times in 215 Posts
Here is something some of you might find interesting.

It's an article by one of the engineers at the company that supplied the laminations for the motor. In the article are some performance graphs and cad drawings of the motor. Oh - also some FEA analysis showing some very impressive flux densities...

Pushing the envelope for electric motors | EETE Automotive

- Enjoy!

- e*clipse
  Reply With Quote
The Following User Says Thank You to e*clipse For This Useful Post:
NeilBlanchard (06-28-2016)
Old 06-28-2016, 03:42 AM   #13 (permalink)
Master EcoWalker
 
RedDevil's Avatar
 
Join Date: Dec 2012
Location: Nieuwegein, the Netherlands
Posts: 3,999

Red Devil - '11 Honda Insight Elegance
Team Honda
90 day: 53.95 mpg (US)
Thanks: 1,714
Thanked 2,247 Times in 1,455 Posts
Quote:
Originally Posted by niky View Post
That makes a whole lot of sense.

And with the electric motors, they can control the exact rate of wheelspin, so even if they lose traction, they still get linear acceleration.
That's why they regulate speed rather than torque.
Torque monitoring (alone) is not optimal as the slightest bump in the road will generate a variance in how much torque you can apply.
By keeping the speed stable a momentary loss of traction will not cause a slipping wheel.

TC works by bringing the speed of the wheel back in line with the others.
No need for that if the speed of all wheels is the same to begin with.

As the weight transfers from the front to the back the front wheels get less grip while the rears get more. But all of them need to turn at the same speed.

That said, if they overdo the speed buildup all 4 wheels will lose grip and the thing does a 4 wheel burnout.
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.


For confirmation go to people just like you.
For education go to people unlike yourself.

Last edited by RedDevil; 06-28-2016 at 03:48 AM..
  Reply With Quote
Old 06-28-2016, 05:32 AM   #14 (permalink)
Master EcoModder
 
Join Date: Aug 2010
Location: Philippines
Posts: 2,173
Thanks: 1,739
Thanked 589 Times in 401 Posts
Quote:
Originally Posted by RedDevil View Post
That's why they regulate speed rather than torque.
Torque monitoring (alone) is not optimal as the slightest bump in the road will generate a variance in how much torque you can apply.
By keeping the speed stable a momentary loss of traction will not cause a slipping wheel.

TC works by bringing the speed of the wheel back in line with the others.
No need for that if the speed of all wheels is the same to begin with.

As the weight transfers from the front to the back the front wheels get less grip while the rears get more. But all of them need to turn at the same speed.

That said, if they overdo the speed buildup all 4 wheels will lose grip and the thing does a 4 wheel burnout.
I'm pretty sure everything is measured against a time delta... possibly the wheels will not accelerate faster (or probably more than x% faster) than the car can.

Buuuuut... if you give the car a GPS speedometer, or maybe even an inertial one... the controller can correct wheel speed to adjust for slippage on the fly. I doubt that's what they're doing here... but it's a fascinating thought (like the GPS-aware gearshift on the Rolls Royce Wraith that predicts upcoming corners)

Parts of the video show the car doing donuts, which shows that yes, what you posited actually can happen.
  Reply With Quote
The Following User Says Thank You to niky For This Useful Post:
RedDevil (06-28-2016)
Old 06-28-2016, 02:13 PM   #15 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: Earth
Posts: 5,209
Thanks: 225
Thanked 811 Times in 594 Posts
Quote:
Originally Posted by niky View Post
And with the electric motors, they can control the exact rate of wheelspin, so even if they lose traction, they still get linear acceleration.
Not much. Ever tried to accelerate on ice by stomping on the gas?

So that's my open-minded question. There is no fundamental problem getting electric motors to apply as much force as desired - even, as with the rail gun, far more than the car's structure could withstand, let alone a human body. But how do you get tires to apply enough force to the road to accelerate at that rate, instead of just sitting there burning rubber?
  Reply With Quote
Old 06-28-2016, 03:34 PM   #16 (permalink)
Permanent Apprentice
 
Join Date: Jul 2010
Location: norcal oosae
Posts: 523
Thanks: 351
Thanked 314 Times in 215 Posts
Possible, with traction as the limitation?

Well, it's been done quite a few times before.

Here's the "White Zombie" - a converted 1972 Datsun pulling sub 2 second 1-60's.
Electric White Zombie Claimed to Do 0 to 60 MPH Dash in 1.7 Seconds (w/video) - Inside EVs
Welcome to Plasma Boy Racing, home of White Zombie, the world's quickest street legal electric door slammer in the 1/4 mile drag.

Here's "Killacycle" (I've seen it in person) doing close to 1 second 0-60. Somehow, the bike and rider have survived AND the rider has managed to hang on.


There's some seriously fun stuff out there - have fun!!
  Reply With Quote
Old 06-29-2016, 02:51 AM   #17 (permalink)
Master EcoModder
 
Join Date: Aug 2010
Location: Philippines
Posts: 2,173
Thanks: 1,739
Thanked 589 Times in 401 Posts
Quote:
Originally Posted by jamesqf View Post
Not much. Ever tried to accelerate on ice by stomping on the gas?

So that's my open-minded question. There is no fundamental problem getting electric motors to apply as much force as desired - even, as with the rail gun, far more than the car's structure could withstand, let alone a human body. But how do you get tires to apply enough force to the road to accelerate at that rate, instead of just sitting there burning rubber?
They're using slicks, from what I can tell, and they're using warmer blankets to keep them at the right temperature and stickiness.

After that, it's all about knowing how much grip they have and adjusting the controller accordingly.

And the ice thing, that can be dealt with via an inertial/GPS traction control system. It still won't accelerate quickly, but you can fine-tune wheel acceleration rates so that you're not needlessly spinning them up.
  Reply With Quote
Old 06-29-2016, 02:33 PM   #18 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: Earth
Posts: 5,209
Thanks: 225
Thanked 811 Times in 594 Posts
Quote:
Originally Posted by niky View Post
After that, it's all about knowing how much grip they have and adjusting the controller accordingly.
Sure, the question is what the heck are they using that has sufficient grip?

Quote:
And the ice thing, that can be dealt with via an inertial/GPS traction control system. It still won't accelerate quickly, but you can fine-tune wheel acceleration rates so that you're not needlessly spinning them up.
Yes, to a degree, but even if it's done perfectly, the acceleration will be slow (if it happens at all), simply because there isn't enough grip between tire & ice.
  Reply With Quote
Old 06-29-2016, 03:04 PM   #19 (permalink)
Karmann Eclectric
 
jray3's Avatar
 
Join Date: Feb 2010
Location: Graham, WA
Posts: 165

Odysseus - '00 Honda Odyssey

MR BEAN - '12 Mitsubishi i-MiEV SE

Karmann Eclectric - '71 VW Karmann Ghia Electric Conversion

BOB - '87 Ford 250 Lariat ext cab
Thanks: 9
Thanked 90 Times in 51 Posts
Quote:
Originally Posted by e*clipse View Post
Possible, with traction as the limitation?

Well, it's been done quite a few times before.
Thank you for finally bringing the White Zombie and Killacycle into this thread. The Zombie did 1.6 second 60 foot runs six years ago with nothing more than a calibrated right foot! That was with street legal tires, no warming blankets or any nonsense other than a burnout. Sure, advanced controls can both win races and improve safety, efficiency, and repeatability, but it's just to replace driver skill and govern the brute force inherent to electric drive. I enjoy regen EVen more than the next guy, and may never buy another pure ICE vehicle, but it's still my series-motored conversions that give the biggest EV grins.

__________________
2012 Mitsubishi i-MiEV, 112 MPGe
2000 Honda Odyssey
1987 F250 Diesel, 6.9L IDI, goes on anything greasy
1983 Grumman Kurbwatt, 170 kW "Gone Postal" twin
1983 Mazda RX-7 electric, 48 kW car show cruiser
1971 VW Karmann Ghia electric, 300 kW tire-smoker
1965 VW Karmann Ghia cabriolet, 1600cc
Have driven over 100,000 all-electric miles!
  Reply With Quote
The Following User Says Thank You to jray3 For This Useful Post:
e*clipse (06-30-2016)
Reply  Post New Thread






Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com