Torque Converter Transmission

[butelja]

To anyones knowlege, has a transmission ever been designed and tested that is composed ONLY of multiple lockup torque converters (2-3) in series? If the unit closest to the engine had the highest stall speed, the unit at the end had the lowest stall speed, and the lockup progressed from front to back as speed increased, the transmission could accomodate a very wide speed range and still have a positive mechanical 1:1 ratio when totally locked. It seems that this could potentially offer interesting characteristics and very high (~8:1) torque multiplication at low speeds.

I realize that this setup would undoubtedly have a lower efficiency then a conventional manual or automatic transmission, and would probably have a very large rotating inertia. But, there might be some specialized offroad applications that it made sense for.

 

[seek]

Temperature increases in the converter are great. This would lead to large oil volume requirements and cooling requirements. An overdrive would also be missed. Not impossible. I guess the control system would be simpler.

 

[jaymaec]

never heard of it- which doesn't mean it hasen't been done!

The Buick dynaflow was a multi-element torque converter with a two-speed planetary box. Normal operating mode was startin direct (high gear) and the converter did all the work.

around '56 they went to a variable-pitch stator (the blade angle was controlled by the valve body)
this gave it increased multiplication for startup and passing.

Some "later" TurboHydros ('70s?) in Buicks (again!) had a dual-pitch or variable pitch stator in the convertor.

The torque converter tends to be large in diameter compared to the planetary gearsets- could be hard to package into a vehicle!

Jay

 

[hoyle]

I think I may be wrong here but didn't the Tucker car have soemthing along tese lines. Just 2 torque converters or was it 2 torque converters and a 2 speed transmission

It may be worth digging out some information on the 'net

Regards

Hoyle

 

[evelrod]

If ya'll are interested in the Tucker automobile (my hobby is antique cars [can't afford a Tucker]) you might try these two sights. Both GREAT .

http://www.tuckerclub.org

and

http://www.si.edu

Rod