Transitional Engine

If 4-stroke then it is possible to use a "steam" engine type eccentric but you need a way to half the amount of times the eccentric moves as you only want the exhaust to open every other rev of the crankshaft. A "Star Wheel" is one method that was used on the early engines, an epicyclic gear box inside the eccentric strap is another. Or you simply need to add 2:1 gearing to drive the exhaust valve and a lobed cam.

The inlet valve is easiest dealt with as an atmospheric one where it is held closed by a light spring and the suction of the moving piston on the induction stroke will pull it open drawing the fuel/air mix with it, again found on most open crank engines so typical of this type of engine.

Star Wheel in action on an Sphinx

I remember something in ME in the 1990s I think of some(maybe Tubal Cain) built an IC motor using a horizontal Stuart Turner steam engine.

I wonder if it would be possible to make it double acting, I know there would be the problem of sealing the piston rod gland.

Ian S C

It would also make for an odd-ball shaped combustion chamber too.

The Mery is a double acting engine and a bit of a half breed being built early on in the evolution of IC engines, and not too odd looking.

Simply leave a large tappet gap between rocker arm and valve stem, this will make part of your sinusoidal motion zero where there is a gap and then a peak where the rocker and valve are in contact. It won't give the quick opening and closing times of a lobed valve but will work. I would still make the intake an atmospheric one as then that will open and snap shut faster.

Edited By JasonB on 12/09/2018 07:49:29

Jason's post of 11/09/2018 07:17:22 appears to be a response to an earlier post which doesn't show in my system. It's the first one in this thread - what's happened to the others?

Jason, thanks for putting on the video on the 1895 Mery Explosive Engine. I've never seen a double acting ignition engine before.

Brian

Gary, there is some moderating going on.

I was doing some reading today on converting a double acting steam engine to IC, the front side of the piston being used as a compressor to supply cooling air for the cylinder.

Ian S C