How Is Work Calculated in a Diesel Engine Thermodynamic Cycle?

AI Thread Summary
The discussion focuses on calculating work done in a Diesel engine thermodynamic cycle using given engine data. Participants analyze the processes involved, including isothermal, isobaric, and isochoric stages, and express uncertainty about the nature of certain processes, particularly whether they are polytropic due to the compression and expansion index. The initial calculation of work done resulted in a negative value, raising concerns about its accuracy. There is a request for clarification on unit conversions and notation related to the compression and expansion index. Overall, the thread seeks guidance on correctly applying thermodynamic equations to determine work in the cycle.
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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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