Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-14-2008, 01:23 PM   #1 (permalink)
EcoModding Apprentice
 
Join Date: Jan 2008
Location: SF Bay Area
Posts: 150

Silver Bullet - '02 VW Golf TDi
Thanks: 5
Thanked 16 Times in 11 Posts
Alternatives to the alternator

We all know you can't run an SI engine very long without some sort of system for recharging the battery, but not all of us are sure to know all the options available. Therefore, I thought I'd open this thread to gather them all together in one place.

1. MetroMPG linked to the TIGER option. Very cool and sure to see actual production.

2. Then there is the tried and true underdrive pulley. For those not familiar with this option, here's how it works. In round numbers, the pulley on your car's alternator is sized relative to the crankshaft pulley to charge slightly at idle (or perhaps a little above idle), and to produce full rated power by about 1500 engine RPMs. The particulars differ from engine to engine, but that's the general idea.

An underdrive pulley is somewhat larger than the OEM alternator pulley, so slows the rotational speed of the alternator. By slowing the RPMs of the alternator the point at which it begins charging is delayed by several hundred RPMs to as much as a 1000 RPMs or more. That delay removes the alternator's electrical load on the engine at low engine speeds, and hence potentially permits better hypermiling in that same low engine speed range.

As an aside, underdrive pulleys are commonly used on water pumps, as well, and for the same reasons.

3. A somewhat more radical approach, but still very doable, is to move the alternator to a position that turns only when the car is rolling. Here is a photo of a (race) car with the alternator mounted above the transaxle and being driven by means of a conventional 'two pulleys and a belt' setup using a CV joint-mounted drive pulley. Again, sizing the pulleys to start charging at your desired speed is key. Oh, and sorry the photo doesn't show much detail, but I'm confident you get the idea.



4. Field circuit switch. Most (but not all) alternators have a so-called 'field circuit' that uses a little juice from the battery to 'excite' the internal circuits of the alternator to make electricity. Without it the alternator will spin, but does not generate any charge. The wire feeding the juice attaches to a terminal on the alternator housing. Identify this wire and then wire in a dash-mounted toggle switch to cut the field whenever you wish.

There are a few options. Surely you guys can come up with some more!

__________________
Best tank ever: 72.1 mpg in February 2005, Seattle to S.F.
New personnal best 'all-city' tank June '08 ... 61.9 mpg!
Thanks to 'pulse-n-glide' technique.
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 01-14-2008, 01:41 PM   #2 (permalink)
EcoModding Apprentice
 
bestmapman's Avatar
 
Join Date: Dec 2007
Location: home
Posts: 133
Thanks: 0
Thanked 1 Time in 1 Post
I like Option 4 the best. Here is why:
A) It is the cheapest.
B) Totally reversible
C) Manually controllable so you can turn it off or on as needed or not.
  Reply With Quote
Old 01-14-2008, 04:47 PM   #3 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,762

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
One alternative for spark ignition is the old tried-n-true magneto.
__________________


  Reply With Quote
Old 01-14-2008, 04:47 PM   #4 (permalink)
EcoModding Apprentice
 
Join Date: Jan 2008
Location: kansas city, MO
Posts: 103

Hyundai Accent - '01 Hyundai Accent
90 day: 38.4 mpg (US)

Gixer - '97 Suzuki GSXR600
90 day: 43.12 mpg (US)
Thanks: 2
Thanked 0 Times in 0 Posts
I think that Tiger thing is pretty cool. With one of those, and an electrically driven power steering power steering pump, AC compressor, etc. you could potentially have no loads on the engine other than the drive shaft.
__________________
  Reply With Quote
Old 01-14-2008, 05:13 PM   #5 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,762

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
One thing I can surmise is that the alternater takes about 10% off a car's fuel efficiency. There are so many independent sources that claim up to 10% improvement after the conventional alternator is taken off-line. That's good to know. For me, a 10% improvement would be 3-4 mpg.
__________________


  Reply With Quote
Old 01-15-2008, 10:54 PM   #6 (permalink)
EcoModding Lurker
 
Join Date: Jan 2008
Location: Silicon Valley, CA
Posts: 23
Thanks: 0
Thanked 0 Times in 0 Posts
Tigers sounds great but...

That article is dated Sept. 2005, is ther a more current article?
Has an exhaust driven alternator been developed and marketed?

If it really works and is available I would be interested in acquiring
one for my own use. If not, then I can see a potential market
if I had the resources to work on this product.
  Reply With Quote
Old 08-17-2008, 11:32 PM   #7 (permalink)
EcoModding Lurker
 
Join Date: Aug 2008
Location: Surrey UK
Posts: 45
Thanks: 0
Thanked 4 Times in 1 Post
just found this Permanent Magnet Alternators and Water Pumps
  Reply With Quote
Old 08-17-2008, 11:48 PM   #8 (permalink)
EcoModding Apprentice
 
Join Date: Jul 2008
Location: N.C. / USA
Posts: 118
Thanks: 1
Thanked 1 Time in 1 Post
interrupt switch 4 engine loads?

Quote:
Originally Posted by bestmapman View Post
I like Option 4 the best. Here is why:
A) It is the cheapest.
B) Totally reversible
C) Manually controllable so you can turn it off or on as needed or not.
For those of us out here who are "electrically challenged" ( I know not to stick anything into a wall socket ... except a plug) , would you elaborate a bit on the specifics of this "load switch"? I am in fear of burning up a very expensive alternator. It sounds great to me! The battery gets lots of charge time, anyhow....My Scangauge shows me great numbers of (downhill) "charge times" but who needs alternator drag while pulling a steep grade? -whitevette
  Reply With Quote
Old 08-18-2008, 12:01 AM   #9 (permalink)
Addicted
 
bbjsw10's Avatar
 
Join Date: Jul 2008
Location: Findlay,OH
Posts: 555

bbjsw10 - '91 Geo Metro Xfi
90 day: 51.06 mpg (US)
Thanks: 0
Thanked 11 Times in 7 Posts
Quote:
Originally Posted by whitevette View Post
( I know not to stick anything into a wall socket ... except a plug) ,
I learned that when I was about 10 with a pair of tweezers OUCH they got real hot real fast.

On another note Option #4 the field wire would have to be killed before turning on ignition. Once you excite the alternator you don't need the field correct? Or not. That is what I thought they taught me in Mechanics class in HS.
__________________
  Reply With Quote
Old 08-18-2008, 02:33 PM   #10 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: NorCal
Posts: 451
Thanks: 1
Thanked 40 Times in 26 Posts
TIGER sounds cool, but would need to be managed by a computer. Also, anything that resembles a turbo sees heat and requires maintainence <anyone have experience with the old Porche 924 T?)

  Reply With Quote
Reply  Post New Thread




Similar Threads
Thread Thread Starter Forum Replies Last Post
Another new lurker - question about shutting down alternator Caelum Rex Introductions 13 01-14-2008 12:40 PM



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