VSTs

VST (continuously variable speed transmission)
All of the major auto makers have development programs or already have installed VSTs on some of their high end vehicles.
The VSTs are complex with lots of pulleys, belts, flywheels, (very expensive and high maintanence) but they offer as much as a 15 to 20% reduction in fuel consumption, not to mention the improved performance in always haveing engine RPMs optimal while varying the gearing.
Now I'm sure this idea has been thought of before, so I'm trying to find out why it won't work.
If you take two splined cones in an oil bath and slide them in and out of each other (not touching), you get countinuously variable gearing. Its much like the torgue converters (wet clutch) used on cars now which use two seperated plates in an oil bath.
I suspect the reason is that there is not enough surface area at one end of the gearing scale and you would get too much slippage, but I would have thought with an oil of proper viscosity and baffling it still might work.
Any Ideas ??? Bill
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Stationary engines have used Constant Velocity Transmissions (CVT,) made by 'Stokes' and 'Reeves' for years. Way back in the twenties they were commonly used on such things as boiler stoker drives and steam driven mill engines. The Achilles heal has always been belt life and not so quiet operation. Excessive noise and changing a belt annually as a preventive maintenance measure did not make them acceptable in automotive use. New materials and computer controls have allowed CVT's to now be used in automobiles. CVT up until recently has been best used on engines that developer their torque at higher RPM's. Those that develop their torque at lower RPM's had a tendency to increase belt wear. One of the Ford models coming in spring will feature a CVT tranny.
mike hunt
Bill wrote:

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Actually, Subaru did think of this in the late 1980's into the early 1990's with the Subaru Justy with the ECVT option. Exact same idea as you just mentioned.

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