Compressed air engine

[Gun Freak]

Makes sense... But I don't understand how that pop off piston pops. Is it the stepped piston concept?

[jackssmirkingrevenge]

Is it the stepped piston concept?

Yes...

[POLAND_SPUD]

How about this

naaahhh somehow I don't see it working

what's wrong with the one with a hammer valve ?

[warhead052]

I don't like that design - too many variables that have to be tweaked

How about this, the pop-off piston is the actual piston. The piston is loose in the cylinder in order to stop it hanging.

Thats what my idea was. And the other one with the air pressure pushing down the piston, and a relief hole to let the pressure out so it can continue cycling.

[Gun Freak]

Is it the stepped piston concept?

Yes...

You make me sound like an idiot lol. Im sticking with my original idea

[jackssmirkingrevenge]

naaahhh somehow I don't see it working

If it doesn't, it was warhead's idea

You make me sound like an idiot lol

I just confirmed your interpretation of the design was correct

[warhead052]

Haha jack, very funny.

[ramses]

JSR, how is pressure relieved from the return stroke?

[Jimmy K]

Gun Freak:

Just a couple questions about what you're trying to do:

Do you want the engine to operate off of a 2 stroke, a 4 stroke, or a different cycle principal?

If you did a "2 stroke", you could make an oscillating cylinder and eliminate the need for a connecting rod. A four stroke would give a stationary cylinder but then you would need a connecting rod and 2 position-actuated valves (either from timing like a cam or springs). I have made a "four cycle" steam / air engine from one of my small Briggs engine by moving the cam lobes 180 degrees. Pretty easy operation, no fabrication. Plus you could strip everything off of a tiny Briggs and it would be about the same size as you were talking about earlier. That would probably be the easiest, although a "two cycle" wouldn't be hard either.

And another thing: every engine needs a flywheel. A flywheel acts as a kind of inertial limiter. Without one, an engine could damage itself by reving too quickly (bending and breaking internals), vibrating excessively, stopping to quickly (a good way to snap a rod), etc.

[Gun Freak]

Ramses, it is vented at the end of the extention stroke.

Jimmy, I am going to put a fly wheel of course.
I'm not big on ICs, so I don't know. Air is injected every time the piston returns.

[ramses]

Ramses, it is vented at the end of the extention stroke.

Jimmy, I am going to put a fly wheel of course.
I'm not big on ICs, so I don't know. Air is injected every time the piston returns.

I realize that. But doesn't air continue to flow while the piston is on the return stroke? The initial air is vented, but would build up again once the piston closes the port.

[Gun Freak]

The piston is loose in the cylinder in order to stop it hanging.

[ramses]

But if that builds enough pressure to do significant work on the flywheel while expanding, doesn't it build enough pressure when compressing to hang?

[Gun Freak]

Personally I don like the design lol but in theory it relies on popping to move, not an airtight seal.

[jackssmirkingrevenge]

But if that builds enough pressure to do significant work on the flywheel while expanding, doesn't it build enough pressure when compressing to hang?

The port would have been closed by the spring, what the diagram should show is a telescoping coupling between piston and crank that will allow the shaft to turn while the piston is locked. Yes, twas a quick concept before Sunday night BBQ

This should work better: