Here's a photo-gif of a stirling engine that runs off a cup of coffee--- Kind of nifty--
Huge engines like this could run from the temp differential of air and water, or from solar energy-- interesting----
When DAF (the company that invented the forerunner of the modern variator) began testing prototypes of their cars one was fitted with a sterling engine. But they are not very powerful. And rather large engines have been made- but they burned coal or wood, and were used just after the turn of the century as stationary engines. Thats a cool gif.
The stirling engine takes advantage of simple pyhsics. the pressure of gas goes up when heated, the pressure of gas goes down when cooled. In a true stirling engine (not a similar hot-air or "flame licker" engine) a specific amount of gas is sealed into the engine, the gas is alternately heated and cooled. When the gas is heated it expands pushing the power piston down, when cooled the power piston is pulled up. very simple. Unless you want to get into how the gas is cooled and heated why the engine doesn't eventually just reach the same temperature in all componets causing it to stop...
That's awesome-- seriously-- I didn't realize the difference between a 'true' stirling, and the one we saw on the coffee cup-- it makes sense though.
Did you see the thread about free/new energy? Do you have any feedback on that? I know Ree posted some tantalizing information about electro-gravitics.
The one on the coffee cup is in fact a sterling engine- not of the original design of sterling engines (from Mr sterling himself) but some other type called like "rothemberg" or something like that. the original sterling engines used a rhombic drive as illustrated in the animated gif attached, the top piston is the displacer piston and the bottom piston is the power piston.
Very little is new! The quote below only includes a few applications of variator type transmissions.
For some reason, I have the feeling that Motobecane originated the Variator drive for mopeds/scooters and others used it under license. I can't find a reference to this now, maybe I am thinking of the DiMoby clutch.
>When DAF (the company that invented the forerunner of the modern variator)
"In 1897, an American, named H.C.Spaulding, patented a transmission with variable diameter pulleys. The idea is said to have been around since at least the 1860s. In 1900 the French Fouillaron car used an infinitely variable belt drive with moveable sheave halves which engaged each other like fingers. In the 1950s US-made garden tractors had tapered split sheaves which opened and closed according to the position of a lever and in 1958, Dr Hub van Doorne's Variomatic transmission was introduced by DAF. This used pulleys with tapered internals which are pressed together or moved apart in order to vary the diameters. About a million cars were built, but those who tried driving them should remember how the engine either seemed to be either struggling or over-revving most of the time."
The cool thing about the DAF car was, that when you put it in reverse you still had the entire transmission working, so you could drive backwards just as fast as you could forward! But you are forgetting one key point the 1958 trans was fully automatic whereas most earlier similar devices were always at least partially manual.
And other earlier cvt type transmissions that actually were automatic have very little in common with the belt driven DAF or the modern variator. But then again the DAF tranmission worked off of engine vacuum mainly, rather then centrifugal force, making it have very little in common either.
I suppose if you consider the method of changing ratios to be more significant than the variable diameter pulley/belt drive portion, then you would be correct.
Incidentally, I was not trying to imply that "cone" or other types of cvt were like the Motobecane variator, only the belt and pulley type.
Actually I'm glad you did bring up the earlier systems. But since many of them operate in a different manner than the modern variator I've never really considered them as such. It is obvious that DAF didn't invent the idea of variable diameter pulleys but their design more closely resembles the modern designs.
Another interesting aspect of the DAF cars was that to apply tension to the belts you used a crank that fitted into the rear bumper and would pull the pulleys away from eacthother depending on what way you cranked. Too bad so few of them sold in the U.S. they really were great cars.
= actually just very weird, what with their 2 cylinder engines, belt driven trans, and ungainly apearance.
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