As immortalised in the 1978 song "Greased Ligthnin'" from the film Grease:

    Well, this car is automatic
    It's systematic
    It's hydromatic
    Why it's greased lightnin' (greased lightnin')

Many automatics these days are manual transmissions with a computer controlling the clutch. They have nothing in common with the slushboxes of old, the oil is just for lubrication.

> Ever driven a vehicle with an automatic transmission rather than a manual gearshift with a clutch? Then you almost certainly used a fluid coupling

Are you sure?

https://en.wikipedia.org/wiki/Continuously_variable_transmis...:

“The most common type of CVT uses a V-belt which runs between two variable-diameter pulleys.

[…]

A belt-driven design offers approximately 88% efficiency, which, while lower than that of a manual transmission, can be offset by enabling the engine to run at its most efficient speed regardless of the vehicle's speed.

[…]

Disadvantages of a hydrostatic CVT include:

Reduced efficiency. Gears are one of the most efficient methods of mechanical power transmission, with efficiencies as high as 90 percent in many cases. In contrast, few hydrostatic transmission systems achieve more than about 65 percent efficiency”

Except a fluid clutch actually works, and a torque converter works even better and has three fans inside it ;-)

I can see the "passive" cylinder getting dragged around a little by viscosity but I don't see how this could transfer even the tiniest amount of power.

That would make much more sense then what the article seems to imply (scientists reinvent a 100 year old torque converter! But worse!!). Of course that headline isn't nearly as fun (scientists develop better model for fluid dynamics in torque converter).

Died at age 68 on April 28, 1945 in Berlin, from shrapnel. The Soviets had begun shelling of Berlin on April 20.

This sort of coupling was used to drive the supercharger on the German BF 109, enabling it to maintain manifold pressure from sea level up to 20,000 ft. with a single stage supercharger without throttling. Use of such couplings in automobiles didn't occur until after the war.

https://www.youtube.com/watch?v=NcI67pZe_Ss

> I'm not a fan of the bias towards "Gears are old tech, and that makes them bad"

If the gears don't at least require an app with a subscription and regular updates to use, they must be old tech

/sarcasm

I don't see how it could even have any measurable torque.

You could improve it by making the cylinders have sticky-out bits that would scoosh the fluid around better, like little paddle wheels, and if you wanted to get some serious torque transfer you'd push the two paddle wheels so close together that the paddles actually kind of intersect.

This could have been designed in CFD in an afternoon. Building it in real life is always somewhat cool but the amount of hype they're putting on this is crazy.

Or slushboxes …