From: Vadim Kogan (vadim@XCF.Berkeley.EDU)
Date: Thu Jun 12 2003 - 08:09:53 PDT
On Wed, Jun 11, 2003 at 08:29:42PM -0700, Jim Newton wrote:
>
> Hi All...
>
> A while back I saw a write up on an experimental HMMWV being evaluated
> by the military that was fitted as a hybrid...electric generator
> connected to the diesel engine, and a powerful electric motor at each
> wheel.
>
> Since there were no drive lines or drive axles, all four wheels could
> mechanically steer, and they could steer really tight...all the way to
> 90 degrees each way! This was great for parallel parking!
>
> The really cool part was that it could also pivot about its center
> like a tank by reversing the motors on one side and forwarding the
> motors on the other. It just spun right around with the wheels all
> pointed straight!
>
> I believe it had the same standard 6.5 diesel engine connected to a
> generator instead of the transmission and transfer case. No batteries
> were needed that I can remember, so the weight was comparable to a
> standard HMMWV.
>
> I just looked on Google and found this one, but I think it is
> different than the one I saw but similar specs:
>
> http://www.pei-idt.com/hmmwv1.htm
Correct, PEI was the main contractor. The motors were produced by UQM
(www.uqm.com). There were 2 modifications: one with two motors (front &
rear) and one with four motors (one per wheel), the latter called
"tactical".
UQM does not want to deal with individuals, unfortunately. So they would not
sell me any of their motors and controllers :-( I am still investigating
other options, since hybrid configuration has a lot of advantages.
On top of what you've mentioned before, there's also reduced noise, all the
way to the point of "stealth" mode: operation on batteries only. Hybrid
HMMWV has better parameters (more torque -> better acceleration and uphill
speed). It also gets more efficient. In UQM tests it went from 8MPG to
16MPG.
While I didn't know that they had actual 4 wheel steering, it would not
surprise me. However, overall I like the design of Shadow RST-V even more
than Hybrid HMMWV. Except that I've got a HMMWV and I could possibly hope to
convert it to hybrid, but I'll probably never get my hands on one of the
Shadows.
Shadow RST-V (google it, it's out there) is also a hybrid. However, the
motors are in the hubs(!). Now there is even less mechanical linkage, and
they can pull the wheels in(!) and lower the suspension for transportation
purposes (there are flaps on the hood above the wheels, so that the front
wheels go through the hood when lowered). It has even bigger clearance than
the HMMWV and an arch in the center of the bottom (gets you over rocks
better too, but that's not why :) It was designed to be transported in
various aircraft (hence the ability to pull in the wheels and lower itself
almost to the ground, plus the arch to go over the ramp).
Vadim.
This archive was generated by hypermail 2.1.4 : Sat May 07 2005 - 20:21:44 PDT