Alternative drive system for sleds

[deaner]

With the amount of power sleds are pushing these days, just wondering if modern technology has presented any options for a completely different drive system. Ditch the CVT and chaincase (or belt drive) and have some kind of direct drive. Could even open up the possibility to mount the engine sideways and narrow machines even more.

Is this a pipe dream or is it possible without being super heavy?

 

[moyiesledhead]

Mercury had a direct drive of sorts in the '70's. Old tech seems to morph into new tech these days, so who knows. Merc also had engine reverse back then.

 

[ippielb]

Diamond drive...? I had the idea a while ago about putting a V-Twin two stroke in a sled, that right there would narrow it up more then enough to get the sled narrow. They already have v-twin technology, diamond drive can be brought back and improved by not using Chinese bearings.

 

[deaner]

The only thing is then you still have the CVT system. I was thinking more like a centrifugal slip clutch or something like that that would engage at a certain rpm and then the power transfered through a small gear box...so I guess something like a diamond drive.

Just wondering if there are any other possibilities to get away from the CVT system or is it the most efficient method of power transfer for a snowmobile.

 

[ippielb]

Unlimited gear ratios with using a CVT system, it is the most practical, and keeps a two stroke in their power band the most. The only other option would be to have a diamond drive on the end of a v-twin that has an internal wet clutch. But then you would need to find a way to dampen the harsh engagement. Belts are very forgiving in comparison to direct drive because a belt can slip, and driveshafts break.

 

[ABMax24]

I think it would be hard to improve upon the current belt drive systems without adding a huge amount of weight, complexity, or cost to a machine. Now that being said I could see a system using electronic solenoids or servos to control the clutches to both improve trail fuel economy and all out performance at the flip of a switch.

I guess it would be possible to build a system similar to a street bike transmission where the gear shifting and clutch was electronically controlled leaving just a throttle and brake control on the handlebars. The major flaw with such a system is current 2-strokes are designed with a very narrow peak power range which wouldn't work well with a transmission shifting through it.

There are CVT transmissions used in that automotive world that might be able to be used as a model to build one for a snowmobile, but the efficiency losses still remain, and again weight would be a huge issue. I think in this application it is easier to overcome losses in efficiency by producing more power at the crankshaft.

Another thing is the ease of servicing of the current systems, many of use can rebuild our clutches with basic mechanical knowledge, and changing parts on the trail is relatively common. Move into a more complex system and this no longer remains possible.

Now mounting the engine longitudinally would allow for some interesting chassis designs, but again where does the 2 stroke pipe go, and if a belt drive is still used changing belts would be a real pain.

I'm sure manufacturers have and possible are still looking at this, but of course if they have a system that works we won't know until it is released for sale.

 

[ABMax24]

I guess the one thing I left out would be an electric drive system, where a motor turns the track and a generator is bolted to the engine. This would allow near limitless mounting positions as there are no mechanical drive train components, and it could even be built with a small battery to allow for more power output than the engine alone could provide for brief periods. Weight would still be an issue as a 150+hp motor and generator can't be light. But this really just sounds like a Prius on snow.

 

[deaner]

I guess the one thing I left out would be an electric drive system, where a motor turns the track and a generator is bolted to the engine. This would allow near limitless mounting positions as there are no mechanical drive train components, and it could even be built with a small battery to allow for more power output than the engine alone could provide for brief periods. Weight would still be an issue as a 150+hp motor and generator can't be light. But this really just sounds like a Prius on snow.

Just imagine how good we could feel about ourselves though? We could look down on those without one of these and know deep down we are better than them.

I thought about the electric thing. Can you imagine if there was a huge leap in battery technology and it really was feasible to just charge your sled and ride all day on a charge. Would make for some insane snowmobiles.

 

[jpmez69]

Pure electric sleds will become a reality. The advances in storage capacities have moved forward 10 fold. Siemens is developing batteries with high voltage capacitors in a controlled energy release. Pound per pound, nothing will come close to it. Add regenerative qualities, potentially a sled could run all day. Electric sleds will be a design challenge for sure. Compared to Electric motorcycles and dirtbikes, sleds see huge rolling resistances. Ski and hyfax friction, Track tension and of course 5 feet of snow in front of it. Trail sleds will be the first to see it. Not to mention guys fiddling under the hood and getting electrocuted. Don't forget fires.

 

[JMCX]

https://books.google.ca/books?id=Rs...QAQ#v=onepage&q=rope cvt transmission&f=false

 

[Got boost want snow]

Back in the day Arctic cat and yamaha both built a hydrostatic drive but were extremely heavy and in cold weather didn't work all that well. Then there were a few direct drive ie; John Deere spitfire they lacked bottom end. Elecric sleds will probably come but a lot of advances must be made before we see them.

 

[moyiesledhead]

http://www.amsnow.com/news/vintage/2008/11/1973-yamaha-ew643b

http://snowgoer.com/snowmobile-features/the-1974-arctic-cat-panther-vip/

 

[longtrack 156]

I think there is a severe problem with the CVT with a rubber belt. I remember the dyno tests back in the day on a 1M 900 Cat 150hp the 900 put 72hp to the track. I see two problems with the CVT, lack of proper rpm management and belt heat. Some of that could be managed by an electronically controlled servo secondary. However I think the real solution would be a hybrid. There is a car in England that is a different hybrid, it has an 11kw generator running the drive train and charging a super capacitor. The generator has enough power to maintain 60mph, however any excess power available, decelerating, braking etc goes into the super capacitor. The car then has 400hp available from the super capacitor for accelerating, you can find this car on Youtube. To me the real solution is to have, say a 50hp gen set with a li-on battery capable of delivering 100hp for 1 minute coupled with a supercapacitor set capable of delivering 200hp all coupled to a 90hp electric permanent magnet motor. Geez the electronics available today we shouldn't have to do with a rubber belt, I have a model airplane setup, motor, speed controller and li-po battery only weigh about 2lbs and can produce 1hp output for about 7min.


I looked for the car on Youtube, couldn't find it, it's not being sold, however you can lease it but the manufacturer still owns it.
However here is one similar;

https://www.youtube.com/watch?v=u6VJ6_4yCkw

 

[knocksum]

DARPA Liquid Piston

Similar to the wankel engine but much needed sophistication. A fraction of the moving parts of any 4 stroke. Ultra light weight. No OIL!

Just need one at 150+ HP and we might have something.

 

[ippielb]

Looks like a rotary engine that Mazda uses in the rx-7 and 8. I’d imagine they’re lore then 150hp plus if you put a turbo on it

 

[lilduke]

A Turbo Diesel Yamaha (chipped & deleted of course) is what I want to see! haha

 

[maierch]

A Turbo Diesel Yamaha (chipped & deleted of course) is what I want to see! haha

Captain Ron at Powerhouse Customs built a tube chassis with a Volkswagen TDI Diesel in it a few years ago. Never did hear how it ended up but they were talking about it being able to handle upwards of 30lbs of boost.

 

[Caper11]

I had a direct drive indy lite in 91, in 95 I upgraded to another indy lite with a chaincase. The 95 would blow the doors off the 91. A direct drive is very inefficient in getting the power to the ground.

The cvt is must on a sled, imagine trying to shift gears or something like that. I actually think the cvt design is pretty good, dodge even put it on one of there cars.
Manufacturers especially one that comes to mind, needs to figure out a better way of controlling resonance and torsion stresses. I understand the theory behind a clutch sheave that has .024" of runout but come on, thats curing the symptom and not the problem.

 

[Dawizman]

How about a "hydraulic coupling" as seen on the koenigsegg regera. Seems to operate similar to a lock up torque converter.

 

[longtrack 156]

I found the item I was looking for, it's a concept developed by a company called, "Riversimple". They use a hydrogen fuel cell to generate 8.5kw to drive the car which is enough to run the car at 60mph, any deceleration or braking is regenerated back to a supercapacitor bank to provide excess power for acceleration. I don't think that would work in a snowmobile but I think a gas genset and the addition of some li-ion battery assist as well as a supercapacitor bank may be something that could work. I believe an 80hp electric motor would easily out perform the current drive system and the dependability would be greatly improved. Capacitors in industry have about a 10 year lifespan, however that's being charged and discharged and discharged at 60 times per second.
Link;

https://www.riversimple.com/the-technology-behind-the-hydrogen-car/