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jkeena1-Visitor
1-Visitor
February 3, 2017
Solved

assistance programming an engine cycle

  • February 3, 2017
  • 2 replies
  • 4539 views

I am trying to program a basic Otto engine cycle and am having difficulty with states 2-3. Between these states, I need to have a numerical method that calculates a new pressure based on the old pressure and relationships with known values and constants. The independent variable is crank angle (theta). I've attached a working copy of the worksheet as well as some notes depicting the logic.

I've attempted to use theta as both a vector index and range variable but haven't been successful.  Thank you in advance.

Best answer by jkeena

Additionally, there was a term missing from the recommended edit, please see attached...

2 replies

V
ValeryOchkov24-Ruby IV
24-Ruby IV
February 3, 2017

I hope this help you

Study 15. Otto Cycle or what is behind the simplified formula

J
jkeena1-VisitorAuthor
1-Visitor
February 3, 2017

Thank you for providing these references. From what I could tell, these are not directly applicable to the approach I am taking with a variable heat release rate at variable timing (spark initiation and duration). They are however a terrific source for future use.

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-MFra-21-Topaz II
21-Topaz II
February 3, 2017

Would fit these changes to the program?

but between P23 and P12 = U0 there is no difference as shown in the graph.

ciclo otto.jpg

J
jkeena1-VisitorAuthor
1-Visitor
February 3, 2017

This looks promising... I'll try to implement and provide more feedback.

Looking further, and this is manageable with the previous routine, P_34_Theta takes the form of P_12_Theta but with a unique Kappa defined by the last state (Pressure and Volume) from 23.  And the final angle/state (4) just drops back to P_i or atmospheric.

Thanks for the recommendation, more to follow.

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