Rethinking the Engine ...  Plan B                                                          

I am starting to get a better understanding of the materials I will need to build an engine. What I have come to realize, is that a type A engine needs a very large amount of gas volume in each of it’s pistons. The power produced by the engine comes from the difference of the volumes of the hot and cold pistons. For a 100°C temperature difference, for each unit of cold volume there is 372/272 or 1.37 units of hot volume. The combined piston maximum volumes would be 2.37 units and the difference of the hot and cold volumes is 0.37 units. That means that only 0.37/2.37 or 15.6% of the piston movements are converted into power. In a type B engine, all of the piston’s power stroke  movement is attempted to be harnessed for power. It's the same amount of work; just using a smaller piston. The upshot is I can make a much bigger B type engine by using the same piston I was planing to make for the A type engine.

The reason I wanted to build a Type A engine in the first place, was to utilize the pistons to pump gas through heat exchangers on the way out of the regenerator. I reckoned that the regenerator would need to be stationary to do so. I think there is a better way.

 I have a new design for a four beam type B engine that will meet my design concepts, is mechanically simpler than the type A and produces more power per volume of the, now, single piston. The model will be build around an 11 inch diameter piston made from a paint bucket and will have an adjustable stroke of up to 1.5 inches (145 cubic inches). The gas inside the piston will be at the hot working temperature and will flow into the piston through a stationary heat exchanger. There will be a small pump at the bottom of the regenerator/displacer vessel, operated by the displacer movement, that pumps air though the cold heat exchanger.