cvt

[gug]

if anyone has comments on cvts, post them here.
here is an interesting idea, honda has developed hondamatic transmisson, which is a hydraulic system.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
taken from 2001 fourtrax foreman rubicon, see transmission page for a more detailed description. or for an alternative description, see press release

HONDAMATIC TRANSMISSION

* The Hondamatic transmission utilizes variable hydraulic pressure and mechanical torque amplification to provide seamless job-handling power and excellent acceleration. Engine power drives a hydraulic pump. The pump, in turn, drives a hydraulic motor with variable fluid capacity. Utilizing pump and motor pistons and a variable-pitch motor-side swash plate, hydraulic capacity and pressure are varied, producing continuously variable output speed. In addition, torque is increased as output-shaft speed is reduced.
* Dash-mounted knob switches to one of three electronic shifting programs: D1 for maximum performance, D2 for maximum torque, and ESPª, Honda's exclusive Electric Shift Program. D1 and D2 modes provide continuously variable transmission output; ESP allows the rider to "shift" the Hondamatic with the touch of a thumb using two push-buttons mounted on the left handlebar.
* The Hondamatic is extremely efficient, with operating efficiencies ranging from 75-81 percent in full-reduction mode and from 87-92 percent when input and output speeds are the same (1:1 ratio).
* The Hondamatic transmission is compact and maintenance-free, with no belts to wear out and replace.
* The Hondamatic is fully sealed and impervious to external contamination.
* The Hondamatic features true engine braking, unlike belt-drive designs.
* Versatile rider controls provide a shift lever to select Drive, Low, Neutral, and Reverse.
* The Hondamatic uses multi-filtered (one large-capacity filter and three strainers) engine oil as hydraulic fluid, simplifying maintenance and ensuring an adequate oil supply in all operating conditions.
<HR></BLOCKQUOTE>

pretty crap efficiency, but i wonder how much of that is from the rest of the transmission, such as the centrifugal clutch? anyway, the transmisson would be pretty programable, hopefully we could set it up for racing quite well. it also works off hydraulic fluid, so if we already had a hydraulic brake system, possible drive and remotely possible steering, we could save some weight by combining all the resovoirs. although this is sorta building in a windscreen, just so we could replace the windscreen jets with blue lights...
ill try and figure out how to contact someone in honda about some help. anyone got any contacts in honda by any chance?

"I come from a land down under,
Where beer does flow and men chunder"

[This message was edited by gug on May 23, 2003 at 08:59 AM.]

[This message was edited by gug on May 23, 2003 at 09:06 AM.]

[gug]

if anyone has comments on cvts, post them here.
here is an interesting idea, honda has developed hondamatic transmisson, which is a hydraulic system.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
taken from 2001 fourtrax foreman rubicon, see transmission page for a more detailed description. or for an alternative description, see press release

HONDAMATIC TRANSMISSION

* The Hondamatic transmission utilizes variable hydraulic pressure and mechanical torque amplification to provide seamless job-handling power and excellent acceleration. Engine power drives a hydraulic pump. The pump, in turn, drives a hydraulic motor with variable fluid capacity. Utilizing pump and motor pistons and a variable-pitch motor-side swash plate, hydraulic capacity and pressure are varied, producing continuously variable output speed. In addition, torque is increased as output-shaft speed is reduced.
* Dash-mounted knob switches to one of three electronic shifting programs: D1 for maximum performance, D2 for maximum torque, and ESPª, Honda's exclusive Electric Shift Program. D1 and D2 modes provide continuously variable transmission output; ESP allows the rider to "shift" the Hondamatic with the touch of a thumb using two push-buttons mounted on the left handlebar.
* The Hondamatic is extremely efficient, with operating efficiencies ranging from 75-81 percent in full-reduction mode and from 87-92 percent when input and output speeds are the same (1:1 ratio).
* The Hondamatic transmission is compact and maintenance-free, with no belts to wear out and replace.
* The Hondamatic is fully sealed and impervious to external contamination.
* The Hondamatic features true engine braking, unlike belt-drive designs.
* Versatile rider controls provide a shift lever to select Drive, Low, Neutral, and Reverse.
* The Hondamatic uses multi-filtered (one large-capacity filter and three strainers) engine oil as hydraulic fluid, simplifying maintenance and ensuring an adequate oil supply in all operating conditions.
<HR></BLOCKQUOTE>

pretty crap efficiency, but i wonder how much of that is from the rest of the transmission, such as the centrifugal clutch? anyway, the transmisson would be pretty programable, hopefully we could set it up for racing quite well. it also works off hydraulic fluid, so if we already had a hydraulic brake system, possible drive and remotely possible steering, we could save some weight by combining all the resovoirs. although this is sorta building in a windscreen, just so we could replace the windscreen jets with blue lights...
ill try and figure out how to contact someone in honda about some help. anyone got any contacts in honda by any chance?

"I come from a land down under,
Where beer does flow and men chunder"

[This message was edited by gug on May 23, 2003 at 08:59 AM.]

[This message was edited by gug on May 23, 2003 at 09:06 AM.]

[gug]

im going to try this attachment thing now, and try to attach a file describing the different types of cvts and their efficiency.
here is the efficiencys from the file: <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>CVT Mechanism Efficiency Range
Rubber Belts 90-95%
Steel Belts 90-97%
Toroidal Traction 70-94%
Nutating Traction 75-96%
Variable Geometry 85-93% <HR></BLOCKQUOTE>

"I come from a land down under,
Where beer does flow and men chunder"

[mike240z]

Quote"The Hondamatic features true engine braking, unlike belt-drive designs."
Obviously belt drive cvts have some engine braking, but not as good as a manual.

[gug]

do you count engine braking as that important? i imagine you can balance the braking power better without worrying about engine braking, and its not like we are going to overheat the brakes around the fsae track.

"I come from a land down under,
Where beer does flow and men chunder"

[mike240z]

Very important as it sounds great.
If there is friction inside the engine, why not use it? If your brakes don't overheat, make them smaller and lighter.

[gug]

yeah, but you know it will never sound as good as the 240z. for all the others, i reckon mike tunes the 240z way too rich just so that he gets the big flames going out the exhaust. anyway, about the brakes.
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> I also ran some numbers through his equations for heat generation and found that the heat generation that we need to produce is far smaller than what 3 solid steel rotors of about 7 pounds each could handle. I haven't found a really good reason for why teams are cross-drilling their brakes... they're probably hurting performance by reducing their swept area. The additional cooling is not only not needed, but even if they did, it would be much better accomplished by using air ducts rather than weakening their rotors with holes. I haven't found any pictures from any formula car series that uses drilled discs. <HR></BLOCKQUOTE>
from in-board or out topic
anyone want to research smaller brakes with just as much feedback/control? i think this years came off a ford laser or something?

"I come from a land down under,
Where beer does flow and men chunder"

[clausen]

The main benefit i see for an inboard rear brake is reducing unsprung weight, which is very important.

If we're clamping the sprocket, then all the weight in the rear braces is the calliper and lines - ace

[gug]

the main problem with sprotors seems to be getting chain lube on the braking surfaces.<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> UMC

Also ran a sprotor and did very well in the competition too. The judges loved that it saved UMC at least a pound of that vital rotating inertia mass. They validated their concept through testing to make sure that the chain grease didn't affect the braking performance, among other testing parameters. These facts were noted during the design finals by the judge giving the "Carrol Smith" talk. <HR></BLOCKQUOTE> from sprocket/rotor combination thread.
of course, this can be solved by running an "inside out" brake and having the bracing connecting the sprocket to the diff offset.
okay, the above sentence makes no sense, so i will try and illustrate.
see the attachment. if you imagine that the outermost edge is where the chain goes (im not drawing all the damn teeth), and inside that is where the brake goes. we can also build some sort of shield into this arrangement so that chain lube does not get onto the brake.

"I come from a land down under,
Where beer does flow and men chunder"

[gug]

cool, jpeg attachements automatically flash up. here is the back view:

"I come from a land down under,
Where beer does flow and men chunder"