Thought this looked interesting:
www.totalmotorsport.com/news/story.asp?ID=2439&Typ...e
Any comments?
PS: Don\'t bother going to the zeroshift website as there is only a holding / contact us type page there.
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Stephen Khoo
www.khoosys.net
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Hum.
If the drive ratio changed instantaneously ("zeroshift")there would have to be an instantaneous change in the speed of rotating masses of the engine and/or transmission and wheels, requiring an infinite torque. There must in practice be some form of accomodation by slip or "winding-up", otherwise there will be an instantaneous disintegration!
There is much more to be learned.
Rudolf
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Interesting article and I would like to hear about how they have made the gearchange so fast AND, at the same time, smoother (so they claim).
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Motorcycle technology? Dog clutch, with permanently meshed gears. Just a guess!
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Found this thread while searching for something else, missed it before.
This is almost certainly one of these new style automated gearboxes with two clutches and an extra shaft.
One clutch and shaft operates all the odd numbered gears, the other clutch and extra shaft operate the even numbered gears.
The design ensures that two gears can be simultaneously engaged, obviously one of the clutches has to be disengaged at this point.
As the next change point is approached the appropriate gear is pre-selected. At the change point itself, which could be automatically or driver controlled, one clutch disengages, the other engages.
With clever use of electronics the operation of the two clutches can be overlapped and slurred to give an extremely smooth change and power transmission on throughout the gear shift. Linking to the engine management system controls the revs.
This system means that extremely rapid shifts can be achieved, but some of the smoothness is lost at full bore acceleration.
Its quite likely that more and more auto transmisisons could go this path as manufacturers strive to achieve economy targets.
Driver variability means wide discrepancies on efficiency of manual autos, whilst torque converter autos are not as efficient but more consistent. This type of box potentially has the best of both worlds.
This type of box is more likely to be seen in truck applications first I think. Hope that explains.
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thanks HJ hadn't seen your article previously.
Looks the same to me too. I have cutaway diagrams of the VW box and Merc's 7 speed auto box if anyone is interested. Latter is a torque converter jobbie though.
Rumour is that 9 different manufacturers might be coming out with dual clutch transmissions, including a 7 speeder for Bugatti.
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