Wilcox Caloric, 1860, open-cycle, regenerator

[spinningmagnets]

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As the Stirling was patented in 1816, this engine of 1860 hoped to make some improvement on the established benefits of the Stirling. I found it to be interesting and perhaps worth discussion. There is no cooler, and it simply exhausts the used hot air through a regenerator to the atmosphere.

It does employ a "flip/flop valve" to control the flow of incoming air and exhausting air.

Before considering the drawings, understand that there are two vertical pistons with a crankshaft above them. The piston on the left is the "power piston" and its cylinder has an open top with a conventional rocking connecting rod on a conventional crankshaft throw. Both pistons have radial seals (piston rings) and neither one is a loose-fitting displacer.

This brings us to the fascinating piston on the right. It has a linear rod with a stationary rod seal, and its cylinder has a sealed top that the rod cycles through, up and down in a straight line. Perhaps we should call this the "gas cycling piston"?

The pistons cycle 75-degrees apart, similar to the well-known 90-degree Alpha. The gas piston on the right leads ahead of the power piston. When the gas piston is at the top, and begins to cycle downwards, the flip-flop valve is aligned so that cool outside air is drawn into the rod side of the piston. When it reaches the bottom of its cylinder, the power piston is about 2/3rds of the way down its cylinder on the left.

Then, the flip flop valve shifts, opening the rod-side of the gas piston to the top of the regenerator. As the gas piston rises, it forces the trapped air to make a U-turn and flow downwards through the hot regenerator, from the top towards the bottom. As that air passes through the regenerator, it comes out being focused like a gas-jet onto the hottest part of the "hot plate" that separates the working gas chambers from the firebox heat.

As the gas piston and the power piston are both moving up, the gas flowing through the regenerator and hitting the hot plate is steadily raising the pressure. As the gas piston reaches the top, the power piston still has 1/3rd of its stroke to harvest power at the point of highest internal pressure.

The flip flop valve shifts and allows the hot internal gasses to exit out the top of the regenerator in a reversed flow, bottom towards the top. This valve has two independent passageways, and as the hot gasses exit the regenerator, cool gasses are flowing into the rod-side of the gas piston.

As with the "soon to be invented" Rider-Alpha, the power pulse lifts both vertical pistons, and the weight of the pistons falling on the far half of the cycle (along with the flywheel) make this engine run smoothly with a relatively small flywheel. My apologies if I mis-understood some part of this.

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[Tom Booth]

Not exactly, but kind of similar in principle to an idea I was exploring a while back, I think maybe:

Resize_20230930_122523_3261.jpg (130.3 KiB) Viewed 82 times

viewtopic.php?t=5578

[Stroller]

I wonder how many of these ever got made.

If an oven door had been fitted to the cavity on the left, the operator would have been able to keep his lunch warm while he waited for the beast to get up to working temperature...

[Tom Booth]

The description of the regenerator found here:

http://hotairengines.org/open-cycle-eng ... ric-engine

Seems very different from what is depicted in the illustration above.

The regenerator design is quite interesting in that it expands radially outward from the center where cold air enters through a central tube. The idea being to provide more room as the gas expands outward from the center and when air travels in the opposite direction, less and less space is available for the gas as it cools.

"allows no more space for air than is absolutely required...making the spaces either wider or thicker at the hot than at the cold end."

In a sense, the geometry of the regenerator assists with the compression of the gas as it cools without the need for any moving parts.