How Is Work Calculated in a Diesel Engine Thermodynamic Cycle?

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SUMMARY

The discussion focuses on calculating work done in a Diesel engine thermodynamic cycle using specific state data. The engine operates through various processes, including isothermal, isobaric, and isochoric, with a compression and expansion index of 1.4. The participant attempted to calculate the work done using the equations for constant volume, constant pressure, and constant temperature but expressed uncertainty regarding the polypropic processes involved. The initial calculation yielded -30431.859 kJ, which was questioned for its validity.

PREREQUISITES
  • Understanding of Diesel engine thermodynamic cycles
  • Familiarity with thermodynamic processes: isothermal, isobaric, isochoric
  • Knowledge of work calculation formulas in thermodynamics
  • Basic principles of pressure and volume relationships in gases
NEXT STEPS
  • Study the implications of the compression and expansion index in thermodynamic calculations
  • Learn about polypropic processes and their equations in thermodynamics
  • Research the conversion of pressure units (Pa to kPa or MPa) and its impact on calculations
  • Explore detailed examples of work calculations in Diesel engine cycles
USEFUL FOR

Students studying thermodynamics, mechanical engineers focusing on engine design, and anyone involved in analyzing Diesel engine performance and efficiency.

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Homework Statement



Engine data for a heat engine cycle, ie: Diesel.

State ...|...1...|...2...|...3...|...4...|
Pressure(Pa) | 1x10^5 | 11.764x10^5 | 11.764x10^5 | 2.207x10^5 |

Volume(m^3) |. 0.826 .|... 0.142 ...|... 0.25 ...|... 0.826 ...|

The gas has a compression and expansion index of 1.4,

determine the work done in (kJ) in the cycle.


Homework Equations



I am not sure. But to have an attempt i would say.

Constant Volume: W = 0

Constant Pressure: W = P(V_2 - V_1)

Constant Tempreture: W = P_2 * V_2 * ln (V_2/V_1)


The Attempt at a Solution



I have done a P-v diagram, and came up with.

1-2: Istothermal (Constant Tempreture)
2-3: Isobaric (Constant Pressure)
3-4: Isothermal (Constant Tempreture)
4-1: Ischoric (Constant Volume)

I am unsure about

1-2 and 3-4 as it could be a polypropic process (Temp/Press/Vol Change) but i think this has to do with the exp/comp index? but not sure how to figure out?

I came up with

-30431.859(kJ)

I think this is wrong, as this would indicate mins work.

Do i need to convert PA to KPA or MPA?

I would welcome any help, advice, or some hints/tips.
 
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Any Ideas Anyone? Would really appreciate it, a very lot.

Does anyone know the Notation for the expansion and compresion index?
 

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