Hot Rod Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
2,855 Posts
Discussion Starter #1
For a couple years now I have been doing napkin drawings of a 28 cylinder double acting engine.

I finally figured out the valving recently. The cylinders themselfs are laid out 14 per side with 8 firing at once (4 at the center and 4 at the 4 outside corners) .

I am using 2 external crankshafts with gears on the ends to turn one flywheel.

Now the engine itself should be fairly balanced. As two internal cylinders reach TDC the oposing two internal cylinders will reach BDC and all will fire down at once which I believe will cancling out each others forces.

Or am I horribly wrong in this and will need balancing on the crankshafts?
524507
 

·
Registered
Joined
·
2,855 Posts
Discussion Starter #3
It is a supercritical c02 engine.

7000 consistent psi is the maximum psi goal with liquid co2 injected into a electric headed fuel rail then that pressure is injected into the cylinder when a opening is exposed in the piston shaft at the top and bottom of travel. The cylinder has a central exhaust port that then runs to condencing tubes returning the co2 into liquid to then be pumped again.

Lots of control with this and most power plants have begun switching over.

The cylinders do not have rings and the engine does not have internal oil. The piston shaft rides on external ball bearings inside sealed enclosures at each end of the piston. Allowing the piston to not touch the walls. The pistons are small at 1" within a 1.1" inside diamiter cylinder. This allows for some pressure to escape. But is needed to keep the system a closed loop.

I abandoned the piston idea because I could not get the valving close. But feel what I have now will work good enough so I do not need to run camshafts.

I will get you drawings on Saturday at the latest.
 

·
Registered
Joined
·
2,855 Posts
Discussion Starter #4 (Edited)
Took longer then I wanted. But here is a 1/1 drawing of one of the cylinders showing a partial opposing cylinder to reflect the opposing forces. Both of the pistons are about to fire outward.
Below is one of 28 cylinders. These use blocks which are bolted together which allows for easy serviceability and ease of manufacturing. The threaded rod runs the length of both cylinder banks with the oil pans being bolted on the end.
524665


Then rods run the length of the cylinder banks crushing them all together as well as allowing support for the spur gears on the ends roughly shown on this 1/8" scale drawing. The spur gears allow me to change the gear ratio to fit the application. I am building this with a maximum rpm of 2100rpm with a 3/1 ratio in a direct drive application.

524666



The link below shows the rough valve layout I will be using. Minus the rings and oil. The piston/rod will ride on packing and twelve 1/4" ball bearings . These pistons fire every 25.7 degrees of 1/1 ratio crankshaft rotation. I believe that the previous firing pistons forces will far exceed the next piston being forced backward as the valve is prematurely exposed. Once again it is far from perfect. But it is simplistic solution to a complicated issue.




Now, I believe the piston forces acting against each other in both directions should cancel each other out. While trying to rip this engine in half mind you. Then the secondary forces should also cancel each other out as the 8 banks fire in a X pattern.

But I am not certain and if it means there will need to be balancing added to the crankshaft now is the time to plan for it.
 
1 - 4 of 4 Posts
Top