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Inventor Demonstrates Infinitely Variable Transmission

Soulskill posted more than 4 years ago | from the clutch-discovery dept.

Transportation 609

ElectricSteve writes with this excerpt from Gizmag: "Ready for a bit of a mental mechanical challenge? Try your hand at understanding how the D-Drive works. Steve Durnin's ingenious new gearbox design is infinitely variable — that is, with your motor running at a constant speed, the D-Drive transmission can smoothly transition from top gear all the way through neutral and into reverse. It doesn't need a clutch, it doesn't use any friction drive components, and the power is always transmitted through strong, reliable gear teeth. In fact, it's a potential revolution in transmission technology."

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First troll post (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#32219848)

first post Muahhaha.

Brilliant. Go Steve! (5, Interesting)

eldavojohn (898314) | more than 4 years ago | (#32219856)

The real icing on the cake is (as mentioned near the end) the secondary drive doesn't require a whole lot of power so it can be run by a flywheel. Infinite torque? Frictionless? This is almost too good to be true, there has to be some catch. Like the primary input drive requires more energy than they expected but I can't see it--although I'm not a mechanical engineer.

This is the kind of thing you like to see -- I hope this man has all the capital he needs and gets that prototype up and running for demonstrations. Plus it's a small time plumber inventor ... these are the kind of news stories an engineer loves to read about.

Re:Brilliant. Go Steve! (3, Insightful)

Mindcontrolled (1388007) | more than 4 years ago | (#32219942)

Well, obviously this is not "frictionless" - it just appears not to use friction as the main force of transmission, like friction-cone type CVTs do. There are other types of CVTs that do not use friction - for example chain-driven CVTs or hydraulic-type CVTs. Theoretical infinite torque is also not exactly new - look at hydristors, for example. I'd love to see more technical detail about what the guy actually invented there, TFA is not exactly helpful when it comes to the inner workings of his gearbox.

Re:Brilliant. Go Steve! (2, Informative)

Raffaello (230287) | more than 4 years ago | (#32220056)

watch the video half way down TFA- it shows in pretty fair detail how the d-drive transmission works.

Re:Brilliant. Go Steve! (2, Funny)

Mindcontrolled (1388007) | more than 4 years ago | (#32220082)

Yeah, thanks - I missed that video. I am slightly too hungover to wrap my head around a video demonstration at the moment, though... Gotta have a look if his patent is already published later.

Re:Brilliant. Go Steve! (1, Informative)

commodore64_love (1445365) | more than 4 years ago | (#32220180)

I think Toyota already invented this with their Prius hybrid car. It uses a traditional planetary gear, but in addition to the gasoline engine and the wheels, it's also tied to an electric motor. The electric motor spins as different rates (or not at all), thereby choosing an infinite number of engine-to-wheel ratios.


I have a VW Beetle with 6 gears automatic. Obviously that's not a CVT, but the huge number of gears keeps my engine hovering at 2000 rpm consistently (between 10 and 60 mph), so it has the same effect as a CVT (keeps the engine at the most efficient spot).

Re:Brilliant. Go Steve! (4, Insightful)

Mindcontrolled (1388007) | more than 4 years ago | (#32220224)

It is indeed similar to the planetary gear coupling boxes in parallel hybrids. And yeah, you are basically right - a 6-gear box holds you sufficiently close to the optimum rpm anyway for practical use. CVTs really shine in heavy machinery, but are not that important for personal cars. Still nice technology, though. To hell with practical importance - all hail those engineering efforts done for the heck of it!

Re:Brilliant. Go Steve! (0)

Anonymous Coward | more than 4 years ago | (#32219952)

I just hope he doesn't sell out to a big car manufacturer who buries it for 30 years because they make more money
with the current system.

Re:Brilliant. Go Steve! (3, Informative)

FooAtWFU (699187) | more than 4 years ago | (#32219964)

By "frictionless" I assume they're talking about something to do with the clutch, where you have two plates that you can jam against each other to transmit power via friction (and if you take them a little distance apart you they have a little bit of slip to them, so that during a gear change can the engine's speed will be smoothly met by the friction until it matches the drive-shaft's speed without any terrible lurch which would damage everything). This thing still has normal mechanical friction, as any set of gears would, but doesn't have any component explicitly designed for friction.

Re:Brilliant. Go Steve! (3, Insightful)

Mindcontrolled (1388007) | more than 4 years ago | (#32220028)

They are actually comparing it to other times of CVTs, which use friction belts driving a pair of cones. Nothing to do with the clutch. The device from TFA uses only gears, in particular a set of planetary gears, so they say that the advantage would be no danger of slippage compared to friction driven CVTs. From what I know, in the usual designs, the slippage problem is not really limiting anyway, though.

Re:Brilliant. Go Steve! (2, Insightful)

Raffaello (230287) | more than 4 years ago | (#32220102)

Slippage limits torque. the whole advantage of this system is that it allows infinitely variable output - from full speed reverse through neutral, to full speed forward, all with full torque limited only by the size of the toothed gears used. All power transmission in this device happens through toothed gears. There are no belts, friction plates, clutches, etc - all toothed gears and only toothed gears, with zero slippage, full torque, and infinitely variable output .

Re:Brilliant. Go Steve! (3, Interesting)

Mindcontrolled (1388007) | more than 4 years ago | (#32220150)

Yeah, but that's basically the working principle of any planetary gear system. If you don't hold any of the components locked in a planetary gear, you can configure the output to be proportional to the ration of the inputs. Combine a CVT with a planetary, and you get an infinitely variable transmission. That's used in hybrid vehicles all the time, and doable with gears only, not using friction components. From quickly skimming over the video, I definitely see a planetary gear setup there. As I said above, I'd love to see more technical detail on that one, TFA does not really make clear what is actually new about this.

Re:Brilliant. Go Steve! (5, Insightful)

camperdave (969942) | more than 4 years ago | (#32220004)

Well, one potential flaw is the eccentrically mounted components. Unless properly counterweighted, at high speed this will cause a lot of vibration.

BTW, couldn't you do this sort of thing with a differential?

Re:Brilliant. Go Steve! (1)

Dunbal (464142) | more than 4 years ago | (#32220060)

In the vid the inventor doesn't really say "infinite torque" - just that the torque is dependent on the size of the gears - which is technically correct. Although gears 50 feet across will not be used on automobiles, they might on ships. And such gears will handle a lot more torque.

Re:Brilliant. Go Steve! (2, Interesting)

roman_mir (125474) | more than 4 years ago | (#32220070)

It is a very interesting approach, the problem that may happen (I don't know, just guessing here) is to locking the lower shaft while trying to go full force, isn't the entire premise of friction basically shifted (sorry for the pun) to the device that will stop or let go of the lower shaft, which needs to be stopped for the torque to be transmitted to the wheels for example? So there are these 2 small black gears if you look at the video, these gears are perpendicular to the lower shaft, sitting on it sideways, is that the one that will be locking the shaft or driving it, because then all of that power difference (either goes to the wheels or goes to the shaft) will be at a point of failure right there, how will they stop and start that one, is there a reliance on the electrical motor there to hold against the driving shaft? If there is, then the electrical motor will have to produce as much power and torque as the main driving engine.

But I maybe wrong completely and just misunderstood this thing totally.

Re:Brilliant. Go Steve! (2, Insightful)

mfnickster (182520) | more than 4 years ago | (#32220182)

isn't the entire premise of friction basically shifted (sorry for the pun) to the device that will stop or let go of the lower shaft, which needs to be stopped for the torque to be transmitted to the wheels for example?

I'm no engineer either, but AFAICS the two counter-rotating shafts share the load between them, and the forward/reverse motion is the difference of the two.

So if one shaft is strong enough to transmit full torque from input to output, there's no problem if you split it between them because the load will always be less than full-power in either direction.

Re:Brilliant. Go Steve! (1)

wagnerrp (1305589) | more than 4 years ago | (#32220188)

That's how the system works. The idea is that however the mechanics work, there is no real load being placed on that lower control shaft, and the secondary motor only need to be strong enough to overcome the friction of the bearings on the sun gear. How well that works in reality, I'm not certain.

Re:Brilliant. Go Steve! (2, Insightful)

maxume (22995) | more than 4 years ago | (#32220222)

My connection is too slow for video, so I have not looked at the thing, but I have seen your criticism raised elsewhere.

Other people have mentioned that the test does not show any load, I expect that, were it truly a breakthrough, they would go ahead and show it doing some ridiculous things (hey, why not?).

Fuel economy (3, Interesting)

Krneki (1192201) | more than 4 years ago | (#32219868)

If this gearbox works we could see a massive decrease in fuel consumption and much better power delivery in our cars.
Because right now the gearboxes are rubbish, they haven't evolved much in the last decades.

Automatic transmissions fail before engines, now. (1)

Futurepower(R) (558542) | more than 4 years ago | (#32219888)

Right now automatic transmissions make a huge amount of money for auto dealerships and other auto repair companies.

Re:Automatic transmissions fail before engines, no (3, Insightful)

Abcd1234 (188840) | more than 4 years ago | (#32220068)

'course, that's why any sane vehicle owner drives stick...

Re:Automatic transmissions fail before engines, no (1)

leathered (780018) | more than 4 years ago | (#32220100)

i.e. most people outside of North America

Re:Automatic transmissions fail before engines, no (1)

JWSmythe (446288) | more than 4 years ago | (#32220192)

    Hey now, there are some of us in North America who prefer to drive manual transmissions.

Re:Automatic transmissions fail before engines, no (0)

commodore64_love (1445365) | more than 4 years ago | (#32220200)

My automatic in my last car lasted 340,000 miles and never needed service. In contrast doesn't a manual need a clutch replacement every 100,000 miles due to wear during shifting? So that means, at least in my experience, the manual costs more.

Re:Fuel economy (1)

hhawk (26580) | more than 4 years ago | (#32219904)

I have a continuously variable transmission in my Prius; I am eager to learn how this differs when I read the article.

I did see something on one of the TV channels that electric cars with their really "high" off the line torque can benefit from this type of transmission because they can get maximum power to the wheels yet never spin.

Electric motors (1, Interesting)

hhawk (26580) | more than 4 years ago | (#32219922)

The article notes that the motor runs (or can run) at a constant speed, which isn't always the case for gas powered engines, although I'm sure they each have a good zone where they produce power effectively. It seems this type of transmission would be perfect for electric motors which can operate at a full constant level of power right off the line. It still seems like you would want a few power settings; one for heavy traffic, one for the city, one for the highway (at least).

Re:Electric motors (3, Informative)

Mindcontrolled (1388007) | more than 4 years ago | (#32219960)

Actually electric motors have a pretty good efficiency over a wide range of power levels. It is ICEs that have a small band of optimal efficiency around a certain rotational speed. So, conventional combustion engines do profit most from this. Besides, electric motors have a rather flat torque curve, so you usually do not need a gearbox for them at all.

Re:Electric motors (3, Informative)

wagnerrp (1305589) | more than 4 years ago | (#32219980)

Reality is exactly opposite. Induction motors are very efficient through most of their operating range, while internal combustion is really only efficient along a narrow band of RPM, which is typically optimized to be highway cruise speed in high gear. With induction motors, they would merely allow for a much simpler controller, one that does not have to provide variable frequency power output.

Re:Electric motors (1)

hhawk (26580) | more than 4 years ago | (#32220008)


Re:Electric motors (3, Insightful)

hedwards (940851) | more than 4 years ago | (#32220266)

That's not entirely true. Dr. Porsche a really long time ago more or less solved that problem. By inventing a vehicle that was propelled by an electric engine but powered by a gas one. Meaning that at all times the gas engine was working at it's most efficient gear ratio, but since the electric engine was driving the actual wheels it could be very efficient and give just the power needed at any given time.

Turbines? (2, Interesting)

Frequency Domain (601421) | more than 4 years ago | (#32220020)

I seem to recall that turbines are incredibly efficient when operating at the optimal spin, but have a very narrow range. Sounds like this new gearing would be great for turbines.

Better with diesel piston engine Re:Turbines? (2, Interesting)

La Gris (531858) | more than 4 years ago | (#32220134)

Turbine without regeneration cycle have approx 30% efficiency and can up 40% efficiency if hot exhaust is returned into the cycle (regeneration). Diesel piston engines actually achieve between 40% and 45% efficiency at optimal constant speed. If you consider turbine systems at optimum efficiency with regeneration and high operating speed are quite large, noisy and need tight maintenance cycles for the finely adjusted and physically resistant blades, this is not suitable for small vehicles. By the way this new gearbox design would be very suited to diesel engines.

Re:Fuel economy (1)

Necreia (954727) | more than 4 years ago | (#32219924)

Check out the video at around 5:30. The biggest difference is that this one isn't friction based.

What a 'simple' yet ingenious idea.

Re:Fuel economy (1)

hhawk (26580) | more than 4 years ago | (#32220000)

It's a really great video. Actually shows how it works and addresses pro's and con's.. i'm very impressed not only with the technology but the reporting and the video.

Re:Fuel economy (2, Informative)

Raffaello (230287) | more than 4 years ago | (#32220126)

Your Prius's CVT has limited torque because your CVT uses power transfer mechanisms other than toothed gears alone. The D-drive uses toothed gears only, not belts, not friction plates, etc. This allows for more torque than other CVT designs.

Lot of misinformation, this IS the way Prius works (2, Interesting)

guidryp (702488) | more than 4 years ago | (#32220242)

I see a lot of people have chimed in without knowledge of how the Prius HSD works. There is NO conventional belt CVT in a Prius.

Prius works almost exactly like this demo. Gear Driven Planetary and Sun gears.

The HSD with its robust gear system without friction drive is what makes it so special.

Here is a simplified demo of how the Prius HSD works:

http://eahart.com/prius/psd/ [eahart.com]

Re:Fuel economy (1)

commodore64_love (1445365) | more than 4 years ago | (#32220262)

In my opinion the most-efficient car that could ever be built, at least in the near future, would look like this but with a battery to provide extra assist:

~250 MPG - http://en.wikipedia.org/wiki/Volkswagen_1-litre_car [wikipedia.org]

The 4 seater version would be identical but twice as wide. Volkswagen did design such a car, with a projected MPG of 150, but then the CEO retired and he was replaced with a new CEO who likes sportscar and gas guzzlers. Oh well.

you already can, just use a manual gear. (0)

Anonymous Coward | more than 4 years ago | (#32220124)

Are you aware that should americans switch to manual gears they would save between 20% and 30% in car's fuel? Think how much are you spending on hybrid technology and such and how a switch to simpler technology could save so much. Do greens drive manual gear cars? I don't think so.

Re:you already can, just use a manual gear. (2, Insightful)

NNKK (218503) | more than 4 years ago | (#32220248)

Where in the world are you pulling 20-30% from?

http://www.consumerreports.org/cro/cars/new-cars/news/2008/10/save-gas-and-money-with-a-stick-shift-10-08/overview/manual-vs-auto-ov.htm [consumerreports.org]

The worst I see in that test is 15%, some are under 10%. And the way I see people in California drive, I'd hate to think what the roads would look like if they were worrying about shifting, too.

Not so needed for electric motors (1)

TheLink (130905) | more than 4 years ago | (#32219874)

Lucky for him ICE cars will probably still be around for the next 20 years. Electric motor cars don't normally need to change gears.

So... (3, Interesting)

Max Romantschuk (132276) | more than 4 years ago | (#32219880)

...when can I fit this on my bicycle?

(I'm serious. Proceeding to read TFA...)

A few notes... (3, Interesting)

Max Romantschuk (132276) | more than 4 years ago | (#32219962)

While quite elegant, this solution requires power input... So not so great on a bicycle...

And as far as cars go, you have to spin a shaft in order to achieve neutral. Which means that you still need a clutch or something for a car to be safe. (If the engine's running and the electric motor spinning the shaft fails the car will go forward... Not nice.)

(Am I the only one who thought that the TFA's statement that understanding these mechanics is dumbing it down? I think it's simple, honestly. I'm not claiming I would have invented it, but I do understand the principle...)

Re:A few notes... (1)

FooAtWFU (699187) | more than 4 years ago | (#32220120)

The relative-spinny-speeds component seems pretty small in comparison to the mechanical force transferred for the actual drive; you could probably achieve it with a couple of batteries if you weren't able to come up with a cute little mechanical widget. I'd mostly be concerned about the bulk of the mechanism and how it would fit onto the bicycle.

Re:A few notes... (1)

Raffaello (230287) | more than 4 years ago | (#32220176)

All you'd need is strong enough brakes - if the power to the control shaft failed, the brakes would cause it to spin anyway because the output shaft would be effectively stopped by the brakes.

Of course once you release the brake the output shaft would jump immediately to highest speed...

At that point, I'd just shut the engine ;^)

Re:So... (1, Interesting)

Anonymous Coward | more than 4 years ago | (#32220050)

It already exists. It is put out by Fallbrook Technologies and is called NuVinci.


Re:So... (1)

chilvence (1210312) | more than 4 years ago | (#32220152)

Yeah, thats the 4 kilo version of a CVT hub. Great if you have a carbon bike and think its too light for some reason, but theres still room for improvement :)

Re:So... (1)

Max Romantschuk (132276) | more than 4 years ago | (#32220264)

I'm familiar with the NuVinci. If I remember correctly it was somewhat limited, but I'd have to check my numbers...

(So far the best competition to the traditional dérailleur I've seen is Rohloff's 14 speed hub.)

Re:So... (1)

Shadow of Eternity (795165) | more than 4 years ago | (#32220230)

Honestly it seems to just be a continuously variable transmission without a significant high or low limit.

And yes, you can get a CVT for your bicycle. If you don't mind having a good 10 pounds back there.

Your official guide to the Jigaboo presidency (-1, Troll)

Anonymous Coward | more than 4 years ago | (#32219906)

Congratulations on your purchase of a brand new nigger! If handled properly, your apeman will give years of valuable, if reluctant, service.

You should install your nigger differently according to whether you have purchased the field or house model. Field niggers work best in a serial configuration, i.e. chained together. Chain your nigger to another nigger immediately after unpacking it, and don't even think about taking that chain off, ever. Many niggers start singing as soon as you put a chain on them. This habit can usually be thrashed out of them if nipped in the bud. House niggers work best as standalone units, but should be hobbled or hamstrung to prevent attempts at escape. At this stage, your nigger can also be given a name. Most owners use the same names over and over, since niggers become confused by too much data. Rufus, Rastus, Remus, Toby, Carslisle, Carlton, Hey-You!-Yes-you!, Yeller, Blackstar, and Sambo are all effective names for your new buck nigger. If your nigger is a ho, it should be called Latrelle, L'Tanya, or Jemima. Some owners call their nigger hoes Latrine for a joke. Pearl, Blossom, and Ivory are also righteous names for nigger hoes. These names go straight over your nigger's head, by the way.

Owing to a design error, your nigger comes equipped with a tongue and vocal chords. Most niggers can master only a few basic human phrases with this apparatus - "muh dick" being the most popular. However, others make barking, yelping, yapping noises and appear to be in some pain, so you should probably call a vet and have him remove your nigger's tongue. Once de-tongued your nigger will be a lot happier - at least, you won't hear it complaining anywhere near as much. Niggers have nothing interesting to say, anyway. Many owners also castrate their niggers for health reasons (yours, mine, and that of women, not the nigger's). This is strongly recommended, and frankly, it's a mystery why this is not done on the boat

Your nigger can be accommodated in cages with stout iron bars. Make sure, however, that the bars are wide enough to push pieces of nigger food through. The rule of thumb is, four niggers per square yard of cage. So a fifteen foot by thirty foot nigger cage can accommodate two hundred niggers. You can site a nigger cage anywhere, even on soft ground. Don't worry about your nigger fashioning makeshift shovels out of odd pieces of wood and digging an escape tunnel under the bars of the cage. Niggers never invented the shovel before and they're not about to now. In any case, your nigger is certainly too lazy to attempt escape. As long as the free food holds out, your nigger is living better than it did in Africa, so it will stay put. Buck niggers and hoe niggers can be safely accommodated in the same cage, as bucks never attempt sex with black hoes.

Your Nigger likes fried chicken, corn bread, and watermelon. You should therefore give it none of these things because its lazy ass almost certainly doesn't deserve it. Instead, feed it on porridge with salt, and creek water. Your nigger will supplement its diet with whatever it finds in the fields, other niggers, etc. Experienced nigger owners sometimes push watermelon slices through the bars of the nigger cage at the end of the day as a treat, but only if all niggers have worked well and nothing has been stolen that day. Mike of the Old Ranch Plantation reports that this last one is a killer, since all niggers steal something almost every single day of their lives. He reports he doesn't have to spend much on free watermelon for his niggers as a result. You should never allow your nigger meal breaks while at work, since if it stops work for more than ten minutes it will need to be retrained. You would be surprised how long it takes to teach a nigger to pick cotton. You really would. Coffee beans? Don't ask. You have no idea.

Niggers are very, very averse to work of any kind. The nigger's most prominent anatomical feature, after all, its oversized buttocks, which have evolved to make it more comfortable for your nigger to sit around all day doing nothing for its entire life. Niggers are often good runners, too, to enable them to sprint quickly in the opposite direction if they see work heading their way. The solution to this is to *dupe* your nigger into working. After installation, encourage it towards the cotton field with blows of a wooden club, fence post, baseball bat, etc., and then tell it that all that cotton belongs to a white man, who won't be back until tomorrow. Your nigger will then frantically compete with the other field niggers to steal as much of that cotton as it can before the white man returns. At the end of the day, return your nigger to its cage and laugh at its stupidity, then repeat the same trick every day indefinitely. Your nigger comes equipped with the standard nigger IQ of 75 and a memory to match, so it will forget this trick overnight. Niggers can start work at around 5am. You should then return to bed and come back at around 10am. Your niggers can then work through until around 10pm or whenever the light fades.

Your nigger enjoys play, like most animals, so you should play with it regularly. A happy smiling nigger works best. Games niggers enjoy include: 1) A good thrashing: every few days, take your nigger's pants down, hang it up by its heels, and have some of your other niggers thrash it with a club or whip. Your nigger will signal its intense enjoyment by shrieking and sobbing. 2) Lynch the nigger: niggers are cheap and there are millions more where yours came from. So every now and then, push the boat out a bit and lynch a nigger.

Lynchings are best done with a rope over the branch of a tree, and niggers just love to be lynched. It makes them feel special. Make your other niggers watch. They'll be so grateful, they'll work harder for a day or two (and then you can lynch another one). 3) Nigger dragging: Tie your nigger by one wrist to the tow bar on the back of suitable vehicle, then drive away at approximately 50mph. Your nigger's shrieks of enjoyment will be heard for miles. It will shriek until it falls apart. To prolong the fun for the nigger, do *NOT* drag him by his feet, as his head comes off too soon. This is painless for the nigger, but spoils the fun. Always wear a seatbelt and never exceed the speed limit. 4) Playing on the PNL: a variation on (2), except you can lynch your nigger out in the fields, thus saving work time. Niggers enjoy this game best if the PNL is operated by a man in a tall white hood. 5) Hunt the nigger: a variation of Hunt the Slipper, but played outdoors, with Dobermans. WARNING: do not let your Dobermans bite a nigger, as they are highly toxic.

Niggers die on average at around 40, which some might say is 40 years too late, but there you go. Most people prefer their niggers dead, in fact. When yours dies, report the license number of the car that did the drive-by shooting of your nigger. The police will collect the nigger and dispose of it for you.

Have it put down, for god's sake. Who needs an uppity nigger? What are we, short of niggers or something?

They all do this. Shorten your nigger's chain so it can't reach any white women, and arm heavily any white women who might go near it.

Not unless it outnumbers you 20 to 1, and even then, it's not likely. If niggers successfully overthrew their owners, they'd have to sort out their own food. This is probably why nigger uprisings were nonexistent (until some fool gave them rights).

Yeah, well, it would. Tell it to shut the fuck up.

A nigger's skin is actually more or less transparent. That brown color you can see is the shit your nigger is full of. This is why some models of nigger are sold as "The Shitskin".

What you have there is a "wigger". Rough crowd. WOW!

They're as common as dog shit and about as valuable. In fact, one of them was President between 1992 and 2000. Put your wigger in a cage with a few hundred genuine niggers and you'll soon find it stops acting like a nigger. However, leave it in the cage and let the niggers dispose of it. The best thing for any wigger is a dose of TNB.

And you were expecting what?

When you came in here, did you see a sign that said "Dead nigger storage"? .That's because there ain't no goddamn sign.

Uh... (1)

mike260 (224212) | more than 4 years ago | (#32219916)

You control the gear ratio by varying the speed at which you spin another axle?
So what drives that crank, and how do you smoothly vary the speed at which it's driven?

Re:Uh... (1)

mike260 (224212) | more than 4 years ago | (#32219968)

Or more specifically: Whatever's driving the control-axle will be fighting whatever's driving the main axle, so it has to be as powerful as the main motor. In which case, why not just use that in the first place?

Re:Uh... (2, Insightful)

Raffaello (230287) | more than 4 years ago | (#32220190)

Not so. The control shaft only has to spin a set of planetary gears, while the output shaft has to drive the entire vehicle. Their torque requirements are orders of magnitude different.

Re:Uh... (2, Informative)

j-stroy (640921) | more than 4 years ago | (#32220238)

I agree, it sure looks like the output torque is generated by pushing against the control drive motor, meaning that maximum torque at ratios less than 1:1 is related to the rating of the control drive system.

The control system has the smaller central gear, so there will be some mechanical advantage that will "step up" the torque the control system can provide, allowing for a smaller control powerplant.

He mentions a kinetic recovery system to power it, which to me indicates an intention for intermittent use. I'm thinking its target purpose is as a no-wear mechanical clutch. Without power input, it sends full power through, which is bad for a failure mode... but good as a clutch. I interpret that the control is least power hungry at ratios close to 1:1 and demands the most power at low ratios; however, I think the "powered zero" requires little power, since there is no torque output.

You could attach smaller version of this device to a PTO to drive the control system variably from the drive motors own power, and control it with an even less powerful electric motor. Stacking the control system(s) like this could allow large scale versions.

Some linkies from the gizmag comments: A Prius drivetrain simulator [sannet.ne.jp] , A John Deere CVT animation [youtube.com]

Re:Uh... (1)

Ellis D. Tripp (755736) | more than 4 years ago | (#32219978)

You could drive it with a small DC motor with an electronic speed control, as shown in the prototype.

Re:Uh... (1)

quantumplacet (1195335) | more than 4 years ago | (#32219996)

Yea, I'm a little confused there as well. I think the idea is that the 2nd axle requires very little power. He discusses this a bit at 7 minutes in, and basically you could power the bottom axle by a very small electric motor, kinetic energy system or something along those lines. Obviously you'll have a loss of efficiency on the 2nd source of power, but since it's so much smaller the gains in efficiency on the main engine should, in theory, outweigh that loss.

Re:Uh... (1)

Pinky's Brain (1158667) | more than 4 years ago | (#32220036)

The presenter in the video claims the energy needed to vary the speed on the second shaft is very small, compared to the input power, so you can use a small electric engine.

Re:Uh... (1)

Alan Nishioka (1517177) | more than 4 years ago | (#32220112)

you use another magic gearbox to drive the control shaft. then you use another magic gearbox to control that gearbox. the control has to be as powerful as the input (or even more powerful if it is geared down). whenever i see something like this, that is so obviously wrong, i wonder why they don't ask a professional. but i think, perhaps, they do ask a professional, who tells them it won't work, so they ignore the professional.

Um, Prius anyone? (1, Informative)

RzUpAnmsCwrds (262647) | more than 4 years ago | (#32219936)

The "transmission ratio is controlled by the relative speed of the motor driven shaft" technique is exactly what's used by the transmission in the Prius (and every other Toyota, Nissan, and Ford hybrid).

Re:Um, Prius anyone? (1, Informative)

Anonymous Coward | more than 4 years ago | (#32220122)

No, it's not, at all. if you take that one random sentence fragment then yes you could apply it to both, or pretty much any automatic transmission for that matter. however, this idea is brand new, and not used anywhere. WTFV, since RTFA won't get you all that far.

Yep, it's the same as "Hybrid Synergy Drive" (1)

YesIAmAScript (886271) | more than 4 years ago | (#32220194)

That is, Toyota's system. Also this same system is used by BMW for their variable ratio steering system.

Brilliant! (0)

Anonymous Coward | more than 4 years ago | (#32219938)

Even if there are future refinements and inventions necessary to unlock the full potential, I applaud his highly creative technique.

Today's CVTs are No Match (2, Informative)

Freshly Exhumed (105597) | more than 4 years ago | (#32219944)

The greatest limitation on today's CVTs is the lack of sufficiently strong materials for the belts. While research and development has already yielded marketable CVTs, they are limited to being paired with relatively low displacement, low horsepower, low torque engines for durability purposes. Your father's Oldsmobile's honkin' huge Rocket V-8 or your cousin Bubba's new pickup truck's V-10 would likely tear any of those CVT belts to shreds. Supposing that this new design is strong enough, those engine pairing limitations could be done away with once and for all.

The biggest advantage is (0)

Anonymous Coward | more than 4 years ago | (#32219946)

Same ratio for forward and backward driving, meaning you can drive just as fast backwards as you can forward.

yeah... http://www.youtube.com/watch?v=S7ipFApsFec [youtube.com]

Hydrostatics... (3, Informative)

crankshot999 (975406) | more than 4 years ago | (#32219950)

Several tractors I have owned have hydrostatic transmissions. These are also infinitely variable, but they use a hydraulic pump and motor to achieve it. They provide very high torque and excellent power transmission. I always wondered why they were never used in cars.

Re:Hydrostatics... (1)

Mindcontrolled (1388007) | more than 4 years ago | (#32220052)

Hydrostatic transmissions sure are nice technology, basically a pair of swash-plate compressors coupled together. I am not exactly an expert on the method, but I think they are rather slow-reacting. Works well for heavy machinery, not so well for cars with fast load changes on the transmission.

Re:Hydrostatics... (5, Informative)

Anonymous Coward | more than 4 years ago | (#32220236)

Fluid friction losses. Recirculating a fluid via a pump in a closed system actually makes a bit of heat, especially when there's a bit of load on it. Works great when something can be built big and doesn't need to go very fast (like the tractor application you mentioned, also used a lot in earth moving equipment and fork-lifts), but when having something that goes fast - not so much. Also if you go too fast, you're either going to have some kind of undesirable hammering or cavitation at a certain point depending on what kind of pump you use to provide hydraulic power.

Some air motors use a tilt-block that does something similar as well in regards to infinite variable speeds, but they're not so much about efficiency as about being able to control speed in industrial environments where electric motors aren't always desired. (Like working around water or in a no-spark environment.)

Clever, but he has a lot of work ahead of him (4, Interesting)

stevel (64802) | more than 4 years ago | (#32219954)

I think the weakness in this design is the need to rotate the "bottom" shaft at a speed equal to the input shaft for neutral. While indeed it doesn't need a lot of power, it's a lot of rotation where, in competing designs, a clutch disengages or the drive motor is idling. I could see a lot of things going wrong if the synchronization was imperfect, or if something went wrong.

How do you start this up from a dead stop? Somehow you have to exactly match the shaft rotation speeds to keep it in neutral before you start moving forward, otherwise there will be a lurch.

I look forward to seeing how this is developed further. It has a lot of potential.

Re:Clever, but he has a lot of work ahead of him (0)

Anonymous Coward | more than 4 years ago | (#32220132)

There is also safety aspect. Clutch == safety if something fscks up with engine controls.

Another thing is input RPM is not always the same. Even in CVTs, engine RPM is lower when you don't need as much torque/power.

Is this the same as a powered differential? (1)

Stultsinator (160564) | more than 4 years ago | (#32219976)

I think so. http://en.wikipedia.org/wiki/Limited_slip_differential [wikipedia.org]

On a straight road, both tires spin at the same speed. On a curve, the difference in tire rotation causes the smaller gears in the differential to spin. If those gears were connected to a motor you could choose to spin the tires at a different rate any time.

I'm not convinced that this is as efficient as a normal gear system, since it will take power to spin the second shaft.

Not quite "new" (0)

Anonymous Coward | more than 4 years ago | (#32219990)

IVTs are certainly not new, and have been around since the 30's. The IVT described is actually similar to eCVTs, which are used on Ford & Toyota hybrids (e.g., Toyota's Hybrid Synergy Drive...both of those use gears (without friction elements), and achieve the ratio variation by the relative rotations of the IC engine & electric motor.

Also, it's not wise to use spur gears in automotive transmissions, since those are notoriously noisy; it's far better to use helical gears.

What this really means is... (1)

3seas (184403) | more than 4 years ago | (#32220006)

An old Volkswagon Bug with this transmission can pull a full weight loaded Semi trailer or flatbed, or locomotive engine. or burn it's tires out trying due lack of the VW bug weighting enough.

Not the first (0)

Anonymous Coward | more than 4 years ago | (#32220012)

That would be the first IVT apart from the one that Torotrak developed years ago, that is.

As a mechanical engineer... (2, Informative)

AtomicOrange (1667101) | more than 4 years ago | (#32220014)

I must admit, I need to clean up my pants now. This is incredible.

Differential, anyone? (0)

Anonymous Coward | more than 4 years ago | (#32220022)

Hasn't he just re-invented the differential gear? I can do this with Lego ... Also, the neutral - a "powered neutral"? It won't freewheel then. I reckon you'll still need some sort of clutch to completely disengage the drive shaft from the wheels, else you'll never be able to push the thing with the engine off...

Re:Differential, anyone? (3, Informative)

Cerylia (669889) | more than 4 years ago | (#32220240)

Yes, the behavior of this "transmission" should look familiar to anyone who has ever played with a differential while experimenting with Lego gears.

With a classic differential (the piece pictured here: http://en.wikipedia.org/wiki/Differential_(mechanics) [wikipedia.org] ), there are four different things rotating, and their speeds are related. The equation is something like (A-B) = (C-D). The problem is that one of these rotating things is very hard to access mechanically - the inner bevel gear, whose axis of rotation moves as the casing of the differential rotates.

It seems like this device is equivalent to a single differential, with one small bonus which explains the additional mechanical complexity: all four rotating parts are easily accessible. There is a shaft coming out of each end, and two shafts exposed in the middle, whose axes of rotation are not moving and therefore motors can easily be attached.

This is a clever re-arrangement of a differential, but I don't really think it will lead to a super-efficient transmission because you still need a secondary motor which needs to be variable speed, and which will be subjected to a potentially wide range of torques. So it just introduces a new problem.

Devil is in the Practical Details (5, Insightful)

BoRegardless (721219) | more than 4 years ago | (#32220034)

It works as a demo very well I , as an ME agree.

The big issue in science and engineering is ALWAYS reduction to practice. The inventor acknowledges this and is working with an engineering firm to make a practical pseudo-production testing model. When you have no clutches, the lack of shock loading means the size of gears and the housing can be substantially reduced, since there won't be an engine load shock issue. There can be issues of loads when parked, though, when another car bumps yours. The other issue is how do you tow such a car when the engine fails or you want to tow it behind a motor home? There may still need to be a "cog" connection for towing.

Issues involved in getting it into a small, produceable and cost effective prototype will tax the engineers. If they can do it, there will be applications in many different fields.

Given that the gear ration can be set by controlling the small electric motor speed, it can be integrated with other electronic control systems easily.

I have to hand it to the guy for coming up with a very clever implementation. This is why we need to support the math, science and physics departments everywhere, because in the end, the world is a physical place and the countries who prosper the most will be the ones with the most technologically up-to-date innovators.

Well, great (1)

rbrander (73222) | more than 4 years ago | (#32220038)

They finally get shifting gears right just as we switch to electric cars that don't need then.

Newton's Third Law? (2, Interesting)

cunniff (264218) | more than 4 years ago | (#32220044)

For every action, there is an equal an opposite reaction. So, when your monster torque motor is spinning the input shaft, surely it is pushing against the counterspinning shafts with exactly that amount of power? In other words - won't the mechanism (electric motor, flywheel, etc.) that keeps the counterspinning shafts running at the desired speed ratios have to overcome this reaction? It's possible that the frictional and mass inertia of the system helps some, but how much?

I'm not an ME, but the explanation of what the required control motor power is relative to input motor power is very thin here. Be very interesting to see what the detailed input / output / control torque & power measurements end up being.

Re:Newton's Third Law? (1)

0100010001010011 (652467) | more than 4 years ago | (#32220246)

It's like Judo. You don't have to spin it as strong as the other shaft, just as fast (accounting for friction losses).

Although I can see some 'unintended accelerations' if that electric motor fails somehow, I'd still want a clutch.

Its a con (0, Troll)

Bork (115412) | more than 4 years ago | (#32220066)

I noticed the problem with that little "show" - the back side has some things that are being kept hidden. Whats on the back side? Variable speed electric motors that are being used to spin those two shafts.

Re:Its a con (2, Insightful)

microcars (708223) | more than 4 years ago | (#32220142)

the speed of those 2 shafts is what controls both the output speed of the device and direction of rotation.
The control over speed and direction is independent of the power input.
How did you think that was manipulated? Mind Control?

Re:Its a con (1)

OzPeter (195038) | more than 4 years ago | (#32220196)

I noticed the problem with that little "show" - the back side has some things that are being kept hidden. Whats on the back side? Variable speed electric motors that are being used to spin those two shafts.

If you managed to stay awake for the complete video they show the backside of the unit. All it contains is the secondary electric motor which is used to spin the secondary shaft - which is the whole point of the mechanical setup.

Of course you could surmise that the thick plastic mounting blocks are also hiding some exotic battery and motor system that really powers the whole device - but then again he is not offering up perpetual motion, so you don't need to go that far

Re:Its a con (1)

TerranFury (726743) | more than 4 years ago | (#32220216)

The motors are supposed to be there, and are an integral part of the design. That's no con; that's totally out in the open.

If you're going to criticize the device, you can say "it's just a planetary gearbox like we've had forever, and it's basically the same as the transmission used in Toyota's Prius;" that might be true. But it's not a scam.

Does this really work like a transmission? (0)

Anonymous Coward | more than 4 years ago | (#32220080)

In a normal transmission speed and torque and changed by the gears. How does this work here? You need a variable speed motor to for the gearbox. So what are the power, torque and speed requirements for this extra motor? If you want to drive really slow but with a lot of torque (accelerating from a stop uphill) does this still work with a small variable speed motor?

Without any measurements/calculations on the efficiency this does not sound like the future of transmissions.

Reverse power input (0)

Anonymous Coward | more than 4 years ago | (#32220086)

Hmm I don't see anywhere whether it allows reverse power input: that is the wheels driving the power train.
That's what's keeping the nifty robotics gearboxes (with high and efficient one step ratios) being used in automotive applications: if you did, and you'd run out of fuel or power, the powered wheels would block (ok for a robot, not for a car).

What concerns me (1)

OzPeter (195038) | more than 4 years ago | (#32220090)

IANAME, but what concerns me over this demonstration is that I do not see any work being generated by the output of this device. All the energy put into the system (from the main and secondary motors) seems to do is to spin an unconnected output shaft - so in effect the practical efficiency of the demo unit is zero.

My gut feeling is that spinning the secondary motor when loading the primary motor is going to take a lot more energy than is implied in the TFA and TFV.

Can anyone enlighten me as to why I am wrong?

Re:What concerns me (1, Informative)

amorsen (7485) | more than 4 years ago | (#32220162)

I think you're exactly right. The invention seems to take a fixed-speed motor and a variable-speed motor of identical power and combine them into a variable-speed motor of identical power.

Re:What concerns me (2, Insightful)

OzPeter (195038) | more than 4 years ago | (#32220204)

I think you're exactly right. The invention seems to take a fixed-speed motor and a variable-speed motor of identical power and combine them into a variable-speed motor of identical power.

However this comment below [slashdot.org] suggests that I am totally wrong

How a planetary-based IVT system works in general (5, Interesting)

caseih (160668) | more than 4 years ago | (#32220116)

At first blush, I'd say that both Toyota and John Deere have already produced something similar. What he appears to have, however, is a system that can smoothly transition (with power) through neutral and reverse. That indeed could be the cool, patented part, as the rest of his transmission is pretty well understood and actually in production already in many of the applications they list for their invention. I don't see any patent application listed, so I can't tell for sure exactly where his breakthrough is.

Here's the fundamental principle by which his transmission works, though: Basically the idea is you supply driving power to a planetary gear system and then use another variable system such as an electronic motor or, in John Deere's case, a hydraulic motor, to take speed (but not power) away from the output shaft by spinning part of the planetary system. If you understand how a planetary gearbox works, this makes sense. So in John Deere's case, the less-efficient hydraulic motor uses a tiny amount of power to control how the actual, geared, power is transmitted to the wheels. Using this system JD has a completely variable system with a particular gear range (this is a tractor after all) that has a powered neutral stop. In the pictures and video you'll note he has two electric motors that control the ratio.

Toyota does something similar with their hybrids, although it's more of a way to efficiently (and brilliantly, I might add) blend the gasoline motor's power with the electric system in an infinitely variable way.

Another way of implementing an IVT, though I don't think it is as efficient, is to use a differential. Power comes in the normal part of the differential (IE spinning the entire gear assembly), and then power comes out one side, and an electric or hydraulic motor attached to the other side (Where the wheels would normally go). You can then use the motor to change the apparent gear ratio, and even reverse it.

Re:How a planetary-based IVT system works in gener (4, Informative)

caseih (160668) | more than 4 years ago | (#32220234)

Hate to reply to my own post, but here is a fairly detailed explanation of John Deere's IVT: http://salesmanual.deere.com/sales/salesmanual/en_NA/tractors/2006/feature/transmissions/8030_option_code_1127_1137_ivt_trans.html [deere.com] . The relevant part is "The John Deere IVT uses a hydromechanical, power-splitting design where a portion of the power is transmitted mechanically and a portion hydrostatically. A hydromechanical transmission is more efficient than a purely hydrostatic transmission because gears carry power more efficiently than a hydraulic pump and motor. By careful selection of the gearing, the John Deere IVT carries a maximum of the power mechanically both at normal field working speeds and at transport speeds, taking maximum advantage of the higher mechanical efficiency while providing the control and versatility of a hydrostatic." And of course this power-splitting is done via a planetary gear system.

I say this not to take away from the D-Drive's awesomeness (John Deere doesn't do reverse without shifting a gear), but to help offer explanations of how it actually works.

The catch (0)

Anonymous Coward | more than 4 years ago | (#32220128)

The catch behind this transmission is that it needs two power inputs: one to spin the "idler" shaft and one that eventually gets passed through the whole thing. If his idler shaft stops moving at neutral (ie power failure), then the car will get thrown into gear and start moving, so a clutch will be needed somewhere anyway.

I doubt the idler shaft requires a lot of energy, and so it shouldn't hurt efficiency that much. The gains you get by using this transmission are probably greater than the losses, assuming you don't let your car idle a lot, which you shouldn't anyway.

Re:The catch (1)

OzPeter (195038) | more than 4 years ago | (#32220158)

I doubt the idler shaft requires a lot of energy, and so it shouldn't hurt efficiency that much. The gains you get by using this transmission are probably greater than the losses, assuming you don't let your car idle a lot, which you shouldn't anyway.

Sucks to be in stop and go traffic which is where the highest idler speed is required as opposed to constant speed freeway driving at top gear - where the idler speed is zero.

Smells scammy (1)

Eravnrekaree (467752) | more than 4 years ago | (#32220154)

If he really had something here that could be so wonderous. Why not try to interest a car manufacturer in licencing to the technology. Instead he says he is "raising money for a prototype", sounds like an investment scam. Ive heard it said there is not anything particularly new about this design, that he basically has taken a design that already exists and labelled it as his own.

Battery vehicles? (1)

Twinbee (767046) | more than 4 years ago | (#32220156)

Would a gearbox still be needed anyway if and when pure electric/battery powered vehicles become the norm? If not, then this invention is great, but a bit late.

HSD in Prius works like this. (1)

guidryp (702488) | more than 4 years ago | (#32220170)

Anyone who knows how a Prius HSD works will see that this is largely the same thing.

Prius uses Sun and Planetary gears with primary from gas engine and EV motors driving other shafts that vary the power from sources.

No clutches, no fixed ratios. Everything is controlled by the speed of the EV controlling motors.

what utter bs!! (0, Redundant)

perryizgr8 (1370173) | more than 4 years ago | (#32220174)

cvt. 'nuff said.

Same concept that drives the Prius (1)

perltooc (933296) | more than 4 years ago | (#32220202)

There's nothing new here, except for the fact that this gentleman has attached some additional rods to a planetary gear system.

And no, the Prius does not use a belt cvt as folks seem to think it does.

http://eahart.com/prius/psd/ [eahart.com]

Transmission innovation (5, Interesting)

Mawbid (3993) | more than 4 years ago | (#32220228)

The Thompson coupling [youtube.com] was invented not long ago, and I remember being amazed that there was anything new to be done in the area of mechanical power transmission. And now this. Are we all done now, or is there more still?

cool...but is it "true" neutral? (1)

MoFoQ (584566) | more than 4 years ago | (#32220258)

it looks cool and promising but is it "true" neutral as in traditional cars where the "input" side is not contributing power but the "output" side is free to spin and not "contribute" power back in?

It would have been cool to see the same demo with a "load" on the output side...perhaps just a heavy disc so once you got the thing up to full speed, the disc would act like inertia and keep spinning even if the D-Drive was in neutral (aka...what you'd have to do if your Toy*ta has a "sticky acceleration" and you need to pop it into neutral)

something to hide? (4, Insightful)

v1 (525388) | more than 4 years ago | (#32220260)

I watched with interest through 3/4 of the video as they continuously refused to show the back side of the model, just loosely discussing the "control shafts" and couldn't get it out of my mind
"pay no attention to the man behind the curtain".

Then finally at the end they showed the back and surprise, there's another motor there, but trying to explain it off that this motor requires far less energy than you're going to gain by using the rest of the system. Maybe this is true, but that's a poor way to present the design, by hiding a serious concern until the last second.

As they wrapped up the video they did admit that this little kink is going to be the determining factor in whether or not it's a useful design. "Why can't they just tap some of the power off the input shaft to manage the control rods?" I thought. Then it occurred to me, the speed would need to be continuously variable, and that's the whole problem they're trying to solve. So, what we have here is a continuously variable mechanism, so long as we can already provide a continuously variable mechanism. (all his D-Drive needs to complete it is, another D-Drive, which would of course need another D-Drive....) Sounds terribly recursive to me. But he didn't go into any detail as to the requirements of this control system, but from what I can tell, it needs to be continuously variable also. He dismissed it as being easy to achieve with something such as an electric motor, which one could argue the same is true of his entire invention...

We'll see. I'll remain skeptical until his design is complete, including the nagging little details of running the control shafts. But really it's an excellent idea even with this problem. It's solved the larger portion of the problem. One other thing that also came to mind is balance. The orbital gears could really get whipping around the sun gear, they'll have to be balanced. Using orbital gears itself at high torque will create new problems also. I'm no mechanical engineer but I also see a potential problem there with torque on the position of the planetary gears since the shaft isn't fixed. You don't usually see floating gears in transmissions.

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