D-drive infinitely variable gearbox
Discussion
http://www.gizmag.com/steve-durnin-ddrive-d-drive-...
Impressive work. Of course, the real test will be when a full prototype is built and the mechanical losses can be tested. I like that he's open about the fact that it may be worse than a conventional transmission. But my hunch is that it will be an improvement, but probably by less than he expects. Either way, it's one to keep an eye on.
Impressive work. Of course, the real test will be when a full prototype is built and the mechanical losses can be tested. I like that he's open about the fact that it may be worse than a conventional transmission. But my hunch is that it will be an improvement, but probably by less than he expects. Either way, it's one to keep an eye on.
I thought this couldn't work, until I found out that the ratio of the speed of the two middle shafts is presently being controlled by an electric motor.
(i.e. there's one motor on the left providing the 'input power' which will run at constant speed and represents the engine, but then there's a second electric motor which is powering the lower of the two middle shafts, which is what changes the gearing ratio.)
I could have this wrong, but it appears that when running in reverse the power is essentially being provided by the 2nd electric motor, which spins the lower shaft to offset the main engine power, and then also spin the output shaft backwards. On that basis, I can see why it works on a bench as a demo, but I'm not sure it will work in a car under load.
(i.e. there's one motor on the left providing the 'input power' which will run at constant speed and represents the engine, but then there's a second electric motor which is powering the lower of the two middle shafts, which is what changes the gearing ratio.)
I could have this wrong, but it appears that when running in reverse the power is essentially being provided by the 2nd electric motor, which spins the lower shaft to offset the main engine power, and then also spin the output shaft backwards. On that basis, I can see why it works on a bench as a demo, but I'm not sure it will work in a car under load.
what is the anticipated power throughput?
DAF did an excellent variomatic belt drive years ago, which was fitted by Ford AVO into some V6 capris of all things...
http://dafownersclub.web.officelive.com/images/clu...
DAF did an excellent variomatic belt drive years ago, which was fitted by Ford AVO into some V6 capris of all things...
http://dafownersclub.web.officelive.com/images/clu...
I wish em well but ive got this awful feeling that manufacturers are only interested in the after sales (parts) market
Cambelts snapping (lets go back to chains)
DMFs failing (lets fit solids)
and all the other "it seemed like a good idea" ideas
and still only 50mpg even WITH more sensors and computer power than the first space launches
Cambelts snapping (lets go back to chains)
DMFs failing (lets fit solids)
and all the other "it seemed like a good idea" ideas
and still only 50mpg even WITH more sensors and computer power than the first space launches
mrmr96 said:
I thought this couldn't work, until I found out that the ratio of the speed of the two middle shafts is presently being controlled by an electric motor.
(i.e. there's one motor on the left providing the 'input power' which will run at constant speed and represents the engine, but then there's a second electric motor which is powering the lower of the two middle shafts, which is what changes the gearing ratio.)
I could have this wrong, but it appears that when running in reverse the power is essentially being provided by the 2nd electric motor, which spins the lower shaft to offset the main engine power, and then also spin the output shaft backwards. On that basis, I can see why it works on a bench as a demo, but I'm not sure it will work in a car under load.
Was only provided by an electric motor, so was easy to control on the demo, full production it can be driven by hydraulic powered by the engine. but you would need an advanced computer control.(i.e. there's one motor on the left providing the 'input power' which will run at constant speed and represents the engine, but then there's a second electric motor which is powering the lower of the two middle shafts, which is what changes the gearing ratio.)
I could have this wrong, but it appears that when running in reverse the power is essentially being provided by the 2nd electric motor, which spins the lower shaft to offset the main engine power, and then also spin the output shaft backwards. On that basis, I can see why it works on a bench as a demo, but I'm not sure it will work in a car under load.
Also people have said it would have problems at high speeds, but the gear box could run at low speed then use a standard gear set to increase the speed after (this could have a manual on/off sector (for long term or emergency neutral like current automatics), and also use a higher ratio Diff.
veryoldfart said:
I wish em well but ive got this awful feeling that manufacturers are only interested in the after sales (parts) market
Cambelts snapping (lets go back to chains)
DMFs failing (lets fit solids)
and all the other "it seemed like a good idea" ideas
and still only 50mpg even WITH more sensors and computer power than the first space launches
cam chains and tensioners fail messily too - look at the VW VR6 motor....Cambelts snapping (lets go back to chains)
DMFs failing (lets fit solids)
and all the other "it seemed like a good idea" ideas
and still only 50mpg even WITH more sensors and computer power than the first space launches
50mpg...........or up to 85mpg with the new blue motion polo and similar
The Polo BM is coming up at 70-75mpg, id only believe even THAT after an extensive run, but too small anyway for my needs
http://www.spritmonitor.de/en/overview/50-Volkswag...
id put a chain against a belt anyday, as for VW VR6's, well i could cite Stag V8s too, the chain was ok but the tensioners used to melt
http://www.spritmonitor.de/en/overview/50-Volkswag...
id put a chain against a belt anyday, as for VW VR6's, well i could cite Stag V8s too, the chain was ok but the tensioners used to melt
Edited by veryoldfart on Wednesday 19th May 19:58
veryoldfart said:
MX7 said:
veryoldfart said:
DAF did an excellent variomatic belt drive years ago
If that's the CVT that used to be in the Volvo 340, we've got very different memories of how good it was!I'm not sure if Audi used it. It wouldn't surprise me. The concept is good, but I think it left a bit to be desired in practice.
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