- #1
Karol
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Homework Statement
At the start of the compression stroke, the cylinder in a diesel motor contains 300[cm3] of air at atmospheric pressure and 270C, and at the end of the stroke the volume is 20[cm3] and manometric pressure 41[atm]. What is the temperature.
Homework Equations
$$PV=nRT\rightarrow \frac{P_1V_1}{T_1}={P_1V_2}{T_2}$$
In an adiabatic process: ##T_1V_1^{\gamma-1}=T_2V_2^{\gamma-1}##
And: ##P_1V_1^{\gamma}=P_2V_2^{\gamma}##
γ for air=1.4
The Attempt at a Solution
First i check if this is an adiabatic process by comparing the initial and final volumes and pressures:
$$T_1V_1^{\gamma-1}=1\cdot 300^{1.4}=2937$$
$$T_2V_2^{\gamma-1}=42\cdot 20^{1.4}=2784$$
So it's not, heat leaks.
So i calculate using the equation of state:
$$\frac{P_1V_1}{T_1}={P_1V_2}{T_2}\rightarrow \frac{1\cdot 300}{300}=\frac{42\cdot 20}{T_2}\rightarrow T_2=840^0K$$
Is my method true?