Why planetary gear sets are used on automatics only?
Why there is no manual transmission with torque converter planetary gear sets?
The advantage would be being able to shift gears without clutch.
In most traditional automatics, TCM (Transmission Control Module) decides gear shift and sends the signal to hydraulics for shifting gears. But I'm thinking of using a lever to operate manually (like gear stick) to achieve the same thing.
The advantage will be no clutch, still manual and no electronics either.
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Probably because once you've factored in the additional weight of the torque converter, oil cooler, radiator, pump etc the additional faff of bolting an automatic gearbox to the back of it is probably negligible. You also can't have a lockup without a computer looking after things so appalling fuel economy will pretty much mitigate any gains from the manual gearbox.
The V60 has paddle shifters and invariably I put it in the wrong gear when trying to drive manually, so I think having to move a stick around would be worse. And I'd probably be one of those people who shove it into third gear and never touch it again.
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I don't know the answer, but I'm sure it would have been done by now.
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The clutchless pre-selector gearbox was in common use in the 1930s.
The traditional Laycock overdrive is really just a 2-speed epicyclic gearbox, operated either electrically by solenoid or manually.
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One of the occupational hazards of claiming a motoring first is that somebody else will point out an earlier example. In this case, the Model T Ford was a sun and planetary transmission:
www.modeltcentral.com/transmission_animation.html
Only pedals to push...
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>> One of the occupational hazards of claiming a motoring first
>>
Ptolemy, 2nd century AD. Re-invented by Richard of Wallingford, 14th century.
en.wikipedia.org/wiki/Epicyclic_gearing
:)
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Indeed. And was he the first?
Audi fell afoul of the Advertising Standards Authority when they claimed to have invented front wheel drive in the mid 30s. Apart from the fact that Citroen were working on 'traction avant', Christie had built front wheel drive race cars before the first world war, and in the previous century, you could buy a two wheeled engine and steering assembly to replace the front axle of your horse carriage.
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What you are describing sounds like 'tiptronic' (in Porsche/VW jargon); a TC auto with manual sequential control.
So it has been done, and there are still such transmissions available; but they are tending to be replaced by twin-clutch two pedal systems or CVTs, primarily to delete the torque converter so as to improve efficiency and thereby fuel economy.
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I recall driving a Saab 900 at Trollhatten in the mid-1990s with a manual (semi-automatic) gearbox and no clutch pedal - a search check brought up:
"For the SAAB 900NG a semi-automatic transmission was available for Turbo models only between 1995 and 1996, mostly for European market.
"The 'Sensonic' clutch variant provided a manual gear lever as in a standard manual transmission car, but omitted the clutch pedal in favor of electronics which could control the clutch faster than an average driver."
Loved it at the time, especially as I have a dislike of automatic transmissions...:-)
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Yes, but wasn't that a robotized manual clutch - like the ones in more recent Citroën and Toyota semi-autos - rather than a torque converter?
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>> Yes, but wasn't that a robotized manual clutch - like the ones in more recent Citroën and Toyota semi-autos - rather than a torque converter?>>
I never mentioned torque converters, only that the system proved excellent to use yet without having to depress a clutch pedal.
Read the description of the system again...:-)
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I never mentioned torque converters...
No, but the OP does, and that's the point of the thread. What you wrote is accurate, just not relevant.
}:---)
PS I liked the 900 too, but I never got to try a Sensonic one.
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This is a bit confused.... the transmission consists of 2 parts - the clutch and the gears. On an auto the torque convertor takes place of the clutch. Manual gearboxes are almost exclusively constant mesh helical gears which are engaged by sliding collars along the shaft to lock the relative cog to the shaft. Autos tend to use epicyclic gears (sun and planet) where gears are selected by braking relative parts of the gear set to give the different gears. I guess this is because there is plenty of oil pressure in an auto (there is an oil pump to run the torque converter), whereas providing this function on a manual would be more difficult, requiring additional kit. Lines are getting blurred these days... without sophisticated electronics the TC is pretty uneconomic, so makers are tending to fit a lot more semi autos - and these tend to be automated manuals with a hydraulically actuated clutch, and gear change. There have been various attempts at TC manuals - eg Citroen's C-matic from the late 70's / early 80s - none very successful!
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Here is an article I have been reading about the new woeful ZF 9 speed auto which is interesting, but most of all, it has a lot of good explanations about the various other transmissions such as DSG and robotoised manuals for comparison.
www.thetruthaboutcars.com/2014/02/zfs-9-speed-9hp-transmission-puts-dog-clutches-on-the-leash/
Last edited by: Shiny Tailpipes on Thu 3 Sep 15 at 14:01
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That is a great article and filled in some gaps in my knowledge.
The current generation of ZF torque converter autos is incredibly good.
Last edited by: DP on Fri 4 Sep 15 at 08:45
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Not to mention the ferromagnetic powder clutch used on the Renault 8 in the 1960s - driver manually selects gear by pressing pushbuttons !
:-)
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Why manual tranny does not use torque converter? - Fursty Ferret
