You might be right, I'm not sure. At least in Otto's patent filing (which is found in English here: https://patentimages.storage.googleapis.com/1f/3f/4c/821c6da

You might be right, I'm not sure. At least in Otto's patent filing (which is found in English here: https://patentimages.storage.googleapis.com/1f/3f/4c/821c6da1070930/US194047.pdf https://patentimages.storage.googleapis.com/1f/3f/4c/821c6da... ) I don't see such an expression. I do see though that the breakdown of the Otto cycle on most sites including German ones (https://de.wikipedia.org/wiki/Ottomotor https://de.wikipedia.org/wiki/Ottomotor) is usually made in a way that just sorts of lends itself to being transformed that way. Well, thanks for making me go through his writings, this was fun!