How do you show the efficiency of an engine is x?

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The discussion centers on determining the efficiency of a hypothetical engine operating in a cycle with an ideal gas. The efficiency formula provided is n = 1 - 1/γ ((1 - (P3/P1))/(1 - (V3/V1))). Participants seek clarification on the types of processes occurring between the states 1, 2, and 3, including whether heat flows in or out during these transitions. A suggestion is made to incorporate the efficiency equation to guide calculations. Understanding the processes involved is crucial for accurately calculating the engine's efficiency.
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Homework Statement


A hypothetical engine, with an ideal gas as the working substance, operates in the cycle shown in the diagram, show the efficiency of an engine is :

n= 1 - 1/\gamma ((1-(P3\P1))/(1-(V3/V1)))

The diagram is basically a section the bottom left quadrant of a circle with an adiabatic process for 3 to 1 to make it a cycle

Homework Equations


ΔU = Qout -Qcold - Work
PV=nRT
gamma = Cp/Cv

The Attempt at a Solution


I really have no idea how to start this
 
Last edited:
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Hi lilliebeth. Welcome to PF. To be sure of how you are labeling the states 1, 2, and 3 could you please answer the following?

The process from 1 to 2 is what type of process? (constant volume, constant pressure, or what?)
Does heat flow in or out of the engine in going from 1 to 2?

The process from 2 to 3 is what type of process?
Does heat flow in or out of the engine for this process?

To get started, you should add another relevant equation: the equation for the efficiency of an engine. That will help you decide what you need to calculate.
 

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