[ausev] CVT transmissions?

[John Penry at Texrocks]

A friend sent this to me.  It is from the NASA tech briefs.

PLUG-IN POWER
The University of California-Davis has licensed a new plug-in hybrid vehicle
technology to Efficient Drivetrains Inc. (EDI) of Palo Alto, CA. EDI was founded in
2006 to commercialize the technology brought about by decades of work by Andy Frank,
professor of mechanical and aeronautical engineering at UC Davis.

Unlike hybrid-electric vehicles currently on the market, plug-in hybrids can
recharge their batteries from a domestic power supply, allowing most short-range
trips to be completed on electric power alone. Frank's designs for a "parallel"
hybrid powertrain allow for significant increases in fuel efficiency. The licensing
package also includes an "intelligent" continuously variable transmission that
automatically selects the right power ratio and eliminates gear shifting.

Plug-in hybrid technology offers a solution to the problem of shifting from
transportation powered by oil to vehicles powered by electricity.
"The plug-in hybrid displaces more oil than any other technique, without a change in
infrastructure," Frank said. EDI hopes to establish its own automotive research and
development center in Davis.
The company plans to partner with auto designers and manufacturers in order to
introduce advanced plug-in hybrid technologies into their vehicles.

Read more here: http://link.abpi.net/l.php?20071206A2

John in Seguin

  ----- Original Message ----- 
  From: Arnaud LACOUR 
  To: AustinEV News Announcements and General Discussion 
  Sent: Thursday, December 06, 2007 6:38 PM
  Subject: Re: [ausev] CVT transmissions?


  it would certainly be possible but the principle behind CVTs is friction and that doesn't go too well with:
  1. saving energy
  2. high torques

  Picture 2 cones, one pointing up and the other down, with a rubber belt between them and a "fork" guiding the belt from one end to the other to go from big ratio (low gear) to small ratio (high gear). Well, that's the idea. This is the choice transmission for mopeds around the world and other light/low torque vehicles. However, it usually is more problematic when torque increases. That's why even if it did work for an EV, the lifespan of the transmission would be questionable. 
  Note that Nissan's CVT are nothing new, for example the DAF cars in the 50s used such transmissions as well as some of the earliest trucks back in the end of the 19th century. GM (Saturn vue), Ford(escape?), Honda, renault, audi, ... there are lots of CVTs and if you're looking for a used one in a wrecked car, you may want to widen your options. 
  the caveat is that modern CVTs have become much more complex and are full of flaky electronics. The "fork" use to be mechanically positioned: a spring would hold it to its initial position (high ratio) and a fly wheel would pull it out depending on the speed of the wheels. Good ol' granpa technology that did job. Nowadays, the fork is gone and it's the cones themselves that change shape to change the ratio. 

  you may want to check the excellent how stuff works article about CVTs. here http://auto.howstuffworks.com/cvt.htm.

  If someone has converted a CVT to EV it's probably from a car that had a powerful v6/v8 or a diesel engine. 

  On Dec 6, 2007 1:35 PM, Donovan Becker <dbecker215 at hotmail.com> wrote:

    I was curious as to whether or not anyone has heard of converted or custom EV's using any of Nissan's CVT transmissions. Everyone seems to be impressed with their "shift 2.0" and they seem to be simpler in nature than what the current hybrids out there use. CVT's would be amazingly beneficial if they can handle the power. 
     
    Donovan


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