Transmision with no gears???

[DSC]

Anybody know anything about this? I just cought the last few seconds of a comercial.

[whateverjames]

i think it uses pullies and belts instead of gears but only available in auto.

[DSC]

Weird. This is all I could find on their website "The world's first continuously variable transmission from Audi blends smoothness and economy. The multitronic® introduces a new dimension of outstanding performance and fuel economy." pullies and belts seem like they would get the same job done as gears...I wonder how it works.

[transient]

I've actually had this idea in my head for something like that for quite some time. Too bad I don't have an engineering degree, I could have made some money <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>

[v8killer]

once they can work it to handle lots 'o power, it's gonna change everything! I think drag racers would love it!

[wherezmytofu]

the nissan tino has the same kinda tranny..no gears so infiniti gear ratio = better gas...only in auto <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>

[kitoro]

the Infiniti G35 has the CVT rite?

[Fuzzy Ewok]

Yeah, read some stuff about those things... &nbsp;I haven't seen anything yet that talks about how much power they can/can't handle, though. &nbsp;CVT's are notorious for not being able to handle much power...though they've been improving, I just don't know how much.

[Nismos14]

actualyl i forge which car but i do recall reading about a car that had 7 speeds with one gear using this technology, it was an automatic, almost tip tronic type, and it did have 7 FORWARD gears IIRC, very interesting idea and i do believe this was a car from the UK or some where in europe

[Fuzzy Ewok]

More info (not too much, though)...

<a href="http://autobuy.about.com/cs/trends/a/nogears16.htm" target='_blank'>http://autobuy.about.com/cs/trends/a/nogears16.htm</a>

I read something a week ago, but I can't find it now. It explained it a bit. Talked about pulleys that were electronically controlled, and able to expand and contract as the belt slid across... Was pretty amazing sounding...####, I wish I could find that.

[transient]

The only thing I was never able to work out in my mind, was how the RPMs would be controlled.

[Fuzzy Ewok]

More info...

&quot;The next question is how does the CVT work? In essence it is a rubber-belt drive shared between two pairs of pulleys. The engine drives the &quot;primary&quot; pulleys, the belts drive from &quot;primary&quot; to &quot;secondary&quot;, and the &quot;secondary&quot; pulleys drive the rear wheels. Forward and reverse direction selection is achieved by dog-clutches in the primary gear box, gear-ratio changing is achieved by varying the effective diameters of the two sets of pulleys together, and the final reduction and differential are in the secondary gear box. Each pulley is made in two halves, a fixed part and a sliding part. The primary sliding part is outboard and the secondary sliding part is inboard. As the gear ratio increases (bottom half of diagram to top half), primary and secondary pulleys slide in unison and the belts move bodily forwards and inwards. Ratio control is principally by flyweights inside the primary drums, assisted or opposed by engine vacuum applied outside or inside diaphragms within the drums in accordance with the operation of an electromagnetic valve (EMV) in the engine compartment. Belt tension is maintained by powerful springs in the secondary pulleys. The final element is the automatic centrifugal clutch at the rear of the engine; this also has a vacuum-operated servo which is activated by the direction selection lever so as to raise the clutch engagement speed except when &quot;forward&quot; or &quot;reverse&quot; are fully selected.&quot;

It comes from this page...
<a href="http://www.volvoclub.org.uk/prof_cvt.htm" target='_blank'>http://www.volvoclub.org.uk/prof_cvt.htm</a>

[tnord]

audi's CVT is not belt driven like the civic hx. audi's is actually chain driven. it's like 5 inches wide and 12 inches long er something, i can't quite remember the exact specifications of it. if someone is really interested i have an european car issue with a big write up on it. &nbsp;think of it like 10 bike chains linked together width wise. &nbsp;as far as the strenght issue goes, you are correct that the systems main limitation is power, but audi's new A6 puts out 240 or more hp iirc, much better than the 120 or whatever for the civic. &nbsp;its a pretty interesting system, i suggest people read up on it.

[Fuzzy Ewok]

Yeah, that's right...I remember reading how Audi's is now chain, not belt...and that's one reason it can handle more power, right? &nbsp;Hmm...I wonder if I read that article you're talking about. &nbsp;lol

[240meowth]

i think the toyota preius has the uni gear gismo as well

[burgy240]

The Audi Multitronic CVT is chain driven with 75 pairs of pins. &nbsp;The chain is really thick. &nbsp;good analogy with the bike chains together thing. &nbsp;Audi claims ZERO slippage even at the 12.7:1 ratio. &nbsp;the chain has 1025 links, is 1.4 inches wide and weighs 3.7 pounds. &nbsp;It is paired with the 220hp 221 ft-lbs torque V6. &nbsp;It is currently in the A6 in europe and will be in only the front wheel drive ?Audi's in the state until 2004. &nbsp;It also can be used with the tiptronic gear box. &nbsp;Each gear is then simply a set position on the pulleys. &nbsp;It is really cool actually. &nbsp;By the way I'm not that well versed on it I just happened to pull out the DEc 2001 Road and Track issue that had it in it yesterday. &nbsp;Also in that issue is the 350Z(on cover) in case anyone wants to check it out. &nbsp;

[thewholefnshow]

I thought that the nissan cvt cleared up a lot of these problems, something to do with using rollers or something as opposed to belts or chains. I remember something along the lines of nissans technology being mind blowing and able to hold power up to 400hp or something disgusting like that. I saw it on howstuffworks.com I thought, but Ic an't find it now.