Stirling Engine Designs                                                                        

I want to build an alpha type Stirling engine where the stationary regenerator sits between two opposing pistons. The pistons could be connected to cranks with two beams (gray).

It is possible that a two beam engine, with cranks of the same size, set at 90 degrees phase, could be the best of all possible configurations. What a coincidence it would be, if this simplest engine was the best. I cannot help thinking that the engine’s power would be optimized if there was an adjustment for timing as the engine ran at different speeds; as is the case of a car engine. 

Adjustments to the timing and volumes can be achieved with as few as four beams

The combined volumes of both pistons follow a sinusoidal curve of changing volume over time that is close to, but not exactly, a sin wave.

By playing with an excel simulator, it looks as though all volume curves are possible by tweaking the crank diameter and the phase difference between the two cranks.

 However, I see that if the phase angle between the cranks is changed, then both the timing and the amplitude of the piston volumes change unpredictably. The same is true if I change a crank diameter, both the amplitude and the timing of the piston volumes change. This is going to make it difficult to design an engine that I can make intuitive changes on the fly.

I’m currently working on a ten beam plan that is mechanically complex. I am concerned about the inertial mass of all the moving parts and about vibration from the many joints rattling.