Photos by Racionerg
The engine consists of one compressor and one expander unit at least. You can use a heater for the heating up the compressed working fluid before the expansion. There is an example for the external combustion engine with free intake and exhaust on the next picture:
The compressor unit compresses the outside air and push it to the heater unit.
The expander unit expands the compressed and heated working fluid and exhaust it outside.
You can use almost all heat sources to heat the working fluid in the heater: Sun radiation, gas-gas heat exchanger, gas-liquid heat exchanger, internal combustion and external combustion unit.
On the picture there is a main shaft in the center of the unit. There is a smaller shaft bellow, that holds the separator and is driven by the excenter unit, fixed on the right side of the main shaft.
The excenter unit keeps the separator close to the rotating piston during the turning of the main shaft. There is a permanent dilatation gap between the separator and the rotating piston, that is closed by the mechanical seal (red color).
You can use one compressor and one expander units, but the working conditions are better if you use two compressors and two expanders.
You can see the P-V-M diagram (SINGLE CYCLE) of the engine with one compressor unit, one heater unit and an expander unit bellow.
(black color = Torque on the main shaft, blue color = expansion P-V diagram, red color = compression P-V diagram)
On the next diagram (DOUBLE CYCLE) there are the P-V-M diagram of the engine with 2 compressors, 2 expanders and one heater.
(black color = Torque on the main shaft, blue color = expansion P-V diagram, red color = compression P-V diagram)
The torque is positive all the time. It is changing with less than 12%, related to the nominal value.
You can see the P-V-M diagram of the 4 stroke OTTO engine on the next diagram (black color = Torque on the cranck shaft, blue color = Otto cycle extended P-V diagram)