Going further down the internet rabbit hole took me to concepts like intermittent combustion and continuous combustion, and rocket and jet engines...

Here's a guy who does slow-mo photography and builds transparent engines:

https://www.youtube.com/channel/UCFH4dWqQQOYkyJZUGT4q5pg

Thanks, FL.

It seems like a common definition of engine is to "convert one form of energy into motion"... so by that broad def, it seems to me that "electric engine" seems a reasonable term, but I understand that obeying rules of popular parlance is worthwhile. Nonetheless, the categories and concepts fascinate me more, if only to highlight similarities and differences in the world of engines (and motors).

I began wondering how to classify a hot air ballon? I mean... it converts chemical energy into a force that's applied to body which ends with motion... like hot exhaust gasses in the cylinder of an engine pushing on a piston, there's hot air pushing on the skin of the balloon... although maybe the distinction between motion and lift/buoyancy are really significantly here. Still, the ways of creating the force are kinda related.

And then there's kites and sails... however, they don't convert energy - they merely use existing forces. Maybe a balloon could fall into that category too, in the sense that it doesn't convert energy, but rather takes advantage of force that's created from manipulating the environment.

That makes me wonder about horse drawn carriages too... or perhaps dog sleds... again forces are used to create motion, but there is no conversion of energy - merely a transference, so one could not call them "engines" I suppose.

Just hypothetical musing. Outstanding wastes of time

And I suppose you could argue that it is all based on "solar energy", as all of the power to do anything has come from the sun if you chase the source back far enough  Our gasoline and diesel fuel comes from the plants that grew,died and decomposed very long ago.  Wind and water energy is using the movement of air and water that was driven by the sun.  The wood, coal, natural gas, oil being used to power the boiler to run the steam engine all came from the plant growth powered by the sun.

For a look at some really early engines - Google Sterling or Atmoshpheric engines.  Early pumping engines for mines used to spray steam into a cylinder, then add cold water, and the condensing steam would create a vacuum that moved a large piston.

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

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

"Since Savery's patent had not yet run out, Newcomen was forced to come to an arrangement with Savery and operate under the latter's patent, as its term was much longer than any Newcomen could have easily obtained. During the latter years of its currency, the patent belonged to an unincorporated company, The Proprietors of the Invention for raising water by fire."... wiki entry for Newcomen Engine

Raising Water by Fire...Gotta love the poetic sense there.

The Newcomen engine isn't that far off from an IC engine, in that gas expansion happens in a cylinder to move a piston... And both Newcomen's engine and the S40 are reciprocating Interesting how the Newcomen decided to uses the force of a contracting gas (vacuum), rather than the expansion (the water boiling into steam).

Dave wrote on 05/26/17 at 11:29:47:


I think Jules Verne went to the moon with that...

Dave wrote on 05/26/17 at 02:40:09:



I guess you could also add geothermal energy - gravitational forces compressing matter and producing heart ... then again: no Sun, no Earth to compress.

Carl Sagan summed it up well - if you wanna make an apple pie from scratch, you first need to create a universe!