The D-Drive Infinitely Variable Geared Transmission
 

Do you think this technology can be apply to production vehicles in 10-15 years?

he's gonna be baller

Conceptually it looks great..

I see one big problem which he is being vague about in the video.

You have to put some power into the "control" shaft that varies the ratio. Where is this power going to come from? In the video he uses an electric motor, but in a car with 100+ HP what will drive this?

Although he did say the amount of energy used to control the second shaft is quite a bit lower than the amount of energy at the input shaft, he's being careful not to say how much.

Common sense will tell you that since the shafts are linked through planetary gears, there will be a limit as to what the difference between input power and control power will be.

For example, accelerating a small car using 50 HP might take 5 HP to operate the control shaft. So you need to apply a total of 55 HP to the transmission to get 50 HP out the rear (this doesn't take into account the normal losses any gear set will always have).

So I don't see how he can say it will be an "order of magnitude" more efficient than normal variable speed transmissions.

Not exactly so revolutionary since I have a project at work using a similar principle of planetary and internal gears.

interesting technology

If you look at a Prius, there are electric motors which can drive the entire car. He's being vague because this is still a proof of concept phase. A separate electric motor hooked up with a KERS system to drive the control shaft? Not an idea that's out to lunch.

Any smart person would be incredibly vague with details at this development point.

I don't see what the big deal is, the end result (infinite gear ratios) is the same as current CVT transmissions.

hes a plumber!!

inspiration!

i need so see fluffy kittens on the left of the screen....

Definitely a very neat concept which obviously works. :)

I can see another problem though. Say you needed to jumpstart a car that had this tranny. Where is your car going to get the power to keep the 2nd shaft spinning (ie Neutral)?

If I were to design something like this, I'd try to attach the motor (ie constant RPM input) to the planetary gear assembly instead. That way if you needed N, no electrical power would be needed. Instead, the planets and ring would just freewheel. :)

Definitely cool-looking doohickey though. For the guy's sake I'd sure hope he filed an assload of patents already. Why is he showing this on Youtube?? Then again, I wouldn't be surprised if a bunch of people in the automotive industry have already developed something similar but failed to put it in production because of performance or cost issues.

^ I'd bet this has already been patented. Engineers have been working with planetary gearsets forever and I doubt that he's actually come up with a different way to use them.

I remember studying them back in 4th year automotive and one of the things we discussed was how changing the relative speeds of either the sun, planet or ring (annulus) would give you infinite ratios.

So as immortality said, there's nothing really new or revolutionary going on here.

This tranny would absolutely suck for racing. The other motor required would be running hardest to produce reverse, and pretty hard to produce dead stop and low gear. Take the total HP and cost of the motors and apply it with a friction clutch and you will be way ahead.

I was arguing this point and others pointed out it might make sense for boats cruising along. Top gear is the only one that doesn't require more energy than usual (assuming you can lock the shaft). The only advantage is that you can apply massive torque in the top gear which would be handy in a big boat.

Stationary applications I'm writing off because electric motors are better suited and generally don't use wide ranging transmissions.

Also, I've got a grudge against planetary gears after needing several 4L80E trannies rebuilt due to failure.

would love to see a working prototype