Scooters usually use CV and centrifugal clutches.
If you use a clutch in slipping mode, with manual gearboxes, you simply bur=
n
it.

-----Mensaje original-----
De: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]En nombre de
Carl Denk
Enviado el: Lunes, 06 de Agosto de 2012 09:16 a.m.
Para: Microcontroller discussion list - Public.
Asunto: Re: [OT] Automatic is more fuel efficient than manual?


As far as I know, all automatics have a fluid coupling (torque
converter) which absorbs some of the jerk when clutch(s) are engaging.
The clutches are either engaged or disengaged, except for the brief
period of changing. There is no continuous slipping mode. The fluid
coupling, though rare, there have been some that are not torque
converters, action can be likened to stirring paint with a paddle. It
takes energy and does generate heat, but the paddle, can, and paint are
not damaged. Today most torque converters have a lock-up feature, to
make the input and output one solid piece via a clutch built into the
torque converter, which results in better gas mileage.

No one as brought up CV (Continuously variable) transmission. This is
basically a very wide V-belt running on tapered pulleys. The distance
between the tapered sides of the pulleys can be adjusted, varying the
riding height of the belt, and the in/output shaft speed ratio. These
have been used for years in industrial applications where they are
generally driven by an electric motor which can be turned off,
eliminating the need for a clutch. In a car, I would think there is a
clutch other than widening the pulley to cause the belt to lose friction
to the pulley sides. Maybe can tell use how that happens.
> I was wondering if the clutch-based automatics also did this maneuver
> (i.e., slip the clutch) and if so, how do they deal with the abusive
> situation where someone tries to hold the car on a hill continuously.
> In a torque-converter type transmission, I think that this is
> relatively harmless so that some people may have gotten into it as a
> bad habit and never noticed problems. Such a person might have a lot
> of problems if he switched to a clutch-type automatic and wasn't aware
> of the difference, unless these transmissions had some way to protect
> their clutches.
>
> Sean
>
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