| Year | Patent Download | Comment | Title | Engine type |
|---|---|---|---|---|
| 1923 | Heinrici patent #369,457 | Piston lubrication for Hot Air Machine | ||
| 1923 | Heinrici patent #376,168 | Hot air engine | ||
| 1923 | Heinrici patent #384,599 | Piston lubrication for Hot Air Machine | ||
| 1941 | Heinrici patent #747,607 | Closed Hot Air Machine |