Stirling engine real-time PV diagram with Arduino Due and 7 inch TFT
My engines 2:30
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Many modificatons since the last video gave me the possibility to measure the PV diagram of the stirling cycle in real-time.
I attached a pressure sensor to the working space and measure the workingpressure 60 times per revolution with an Arduino Due.
Its amazing how fast modern microcontrollers are.
The limiting component is the speed of the pressure sensor which is 2 ms according to the data sheet.
At higher (2000+) rpm I sometimes get false results.
(60s/(2000*60) = 0.5 ms time between pressure readings!!
Does anybody know a faster pressure sensor in the range of 0 - 16 bar (250 psi , 1,6 MPa)?
Before I reached the full potential of the new configuration with a cast iron workingcylinder and piston unfortunately the displacer imploded at 10 bar meanpressure (appr. 15 bar pmax) and 230 watts.
Now I have to decide to machine the displacer more sturdy (which makes it heavier) or to develop some kind of valve or very little leakage of the displacer to reduce the pressure difference that will not lead to more dead space.
If you have any idea how this can be made smart I would be very thankful.
When I machined the new cast iron workingcylinder and piston sealing element with a very tight ´perfect´ fit it had very low friction and nearly no leakage (nice ´bouncy´ feeling).
The engine ran very powerful at start but when it became warm (60 degree C is working temperature for me) the piston element was freeting and the engine stopped.
Now I machine the piston sealing element appr. 0.1 mm smaller than the cylinder and it works well but compression is not as good.
Both (cylinder and piston element) are out of the same cast iron (GG-25) but the piston element seems to expand more (it gets more hot ?).
Has anyone experienced something of the sort?
I would be very happy for any comments and suggestions
Greetings
Ralf
I attached a pressure sensor to the working space and measure the workingpressure 60 times per revolution with an Arduino Due.
Its amazing how fast modern microcontrollers are.
The limiting component is the speed of the pressure sensor which is 2 ms according to the data sheet.
At higher (2000+) rpm I sometimes get false results.
(60s/(2000*60) = 0.5 ms time between pressure readings!!
Does anybody know a faster pressure sensor in the range of 0 - 16 bar (250 psi , 1,6 MPa)?
Before I reached the full potential of the new configuration with a cast iron workingcylinder and piston unfortunately the displacer imploded at 10 bar meanpressure (appr. 15 bar pmax) and 230 watts.
Now I have to decide to machine the displacer more sturdy (which makes it heavier) or to develop some kind of valve or very little leakage of the displacer to reduce the pressure difference that will not lead to more dead space.
If you have any idea how this can be made smart I would be very thankful.
When I machined the new cast iron workingcylinder and piston sealing element with a very tight ´perfect´ fit it had very low friction and nearly no leakage (nice ´bouncy´ feeling).
The engine ran very powerful at start but when it became warm (60 degree C is working temperature for me) the piston element was freeting and the engine stopped.
Now I machine the piston sealing element appr. 0.1 mm smaller than the cylinder and it works well but compression is not as good.
Both (cylinder and piston element) are out of the same cast iron (GG-25) but the piston element seems to expand more (it gets more hot ?).
Has anyone experienced something of the sort?
I would be very happy for any comments and suggestions
Greetings
Ralf
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