×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Electric Motors/Battery Power, etc.

Electric Motors/Battery Power, etc.

Electric Motors/Battery Power, etc.

(OP)
Let me preface this by saying that electric or battery power for cars is NOT my specialty.  However I would be interested in the pros and cons of a "power wheel", ie a powered wheel where the motor provides motive power, regeneration and, braking in one unit.  Given a computerized control system, this would seem to be an ideal way to power a small commuter type car or bike.
One drawback would be heat dissapation.  What else?

RE: Electric Motors/Battery Power, etc.

Regen works great in an urban area as braking constantly occurs.  Regen becomes less useful if the vehicle is driven on the freeway most of the time.  For long milage range, hybrid should be considered.  Whether it's powered by gasoline, diesel, natural gas, or fuel cell, it helps increase the range a vehicle can travel and definitely improves its efficiency.  Electric or hybrid electric technologiies apply not only to small vehicles but as big as a class 8 truck, buses, or even tow tractors.  A configuration in series works best for urban routes; a config in parallel works best for freeway routes.  

RE: Electric Motors/Battery Power, etc.

(OP)
schiao---Thanks for the info, but what I really don't understand is how the regen can be as effective as it needs to be if braking is controlled by conventional means and not by the elect. motor in regen.  I built a small elect. model car and used a rheostat to reverse polarity to the motor for braking.  It was a bit clumsy, I'm not a great model builder, but it worked, albiet at the eventual cost of the motor.  It died of overheat I think.  Now , can this principal be applied to a full size auto?  If so, how do we controll the heat without it becoming overly clumsy?

RE: Electric Motors/Battery Power, etc.

I cannot give you much info since it may become proprietary issues.  But if you plan to throw ALL regen power back to motor, I could imagine your car may not brake smoothly.  You need to sense your brake pedal electronically.  You also need to monitor the load on your motor so you can have a system to decide how much regen can be taken.  Energy storage pack like UltraCapacitor would be best suitable for regen as it's able to absorb/release power rapidly.  For a primitive and simpler way, you may consider resistor bank for dissipating the excessive amount of energy.  We (my company) use regen feature alot as many vehicles we build are buses which run in urban areas.  Sorry I can not offer too many details.  E-mail me if you would like to know some products my company offers.

RE: Electric Motors/Battery Power, etc.

(OP)
Definately. Send anything your allowed to give out. Especially in the area of brake modulation by micro-processer or electronically.  Our tests, so far, show instability in braking as speed changes.  My youngest will be back from Germany this summer (Army Sig. Corps) and he has ideas beyond my comprehension, so what else is new.
my email is    roddav@msn.com

Since i'm 'kinda' slow on the uptake, anything at this point will help.

Thanks,     Rod

RE: Electric Motors/Battery Power, etc.

I cannot describe any more details.  Let me send you our company's info and you should contact our marketing manager.  

RE: Electric Motors/Battery Power, etc.

(OP)
Thanks

RE: Electric Motors/Battery Power, etc.

An electric car typically accelerates at less than 0.1 g- 0.2 g. It needs to brake at the same rate as the surrounding traffic, 1 g . If you wish to rely on electric braking then the electronics and windings have to be designed to take currents 5-10 times the normal loads.

If you decide to forego the electric braking, or use a mechanical brake for serious braking, then a wheel motor seems to me to be an efficient solution. The proviso is that by its nature the windings will be fairly large, hence heavy, hence expensive.

Honda make a wheel motor for bicycles, which is a nice self contained unit, and is fairly efficient. I have only seen it in Japan. For my own electric bike I will be using a small high speed motor with a chain reduction.

Cheers

Greg Locock





Cheers

Greg Locock

RE: Electric Motors/Battery Power, etc.

See my comments on post "current generation during regen braking".

One point is Safety is a big issue.  A brake-by-wire system would never be used alone without some sort of a backup system.  What happens if you lose power to the control module (it is only 1 wire)?  NO BRAKES!  There are regulations on this issue.

One question for Schiao: You mention hybrid and electric vehicle use in large trucks and busses, but they require lots of torque and power.  Especially pulling a full load up a long grade!  I would think that for large trucks and busses, electric drive systems would have a hard time providing the power relative to the typically used turbo diesel.  You would need a lot of battery power to drive some high torque / high speed motors.  I would think hybrids would be ok, but pure electric would be difficult.  Any comments?

RE: Electric Motors/Battery Power, etc.

To FireLover,

You are totally correct.  The only totally electric projects we have dealt with are vehicles like trams or short range delivery truck.  Any other trucks/buses are hybrids.(fuel cells, diesel, gasoline, CNG, LPG,..., etc.)  And all our vehicles do have air braking along with regen systems.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

eBook - Rethink Your PLM
A lot has changed since the 90s. You don't surf the Web using dial-up anymore, so why are you still using a legacy PLM solution that's blocking your ability to innovate? To develop and launch products today, you need a flexible, cloud-based PLM, not a solution that's stuck in the past. Download Now
White Paper - Using Virtualization for IVI and AUTOSAR Consolidation on an ECU
Current approaches used to tackle the complexities of a vehicle’s electrical and electronics (E/E) architecture are both cost prohibitive and lacking in performance. Utilizing virtualization in automotive software architecture provides a better approach. This can be achieved by encapsulating different heterogeneous automotive platforms inside virtual machines running on the same hardware. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close