Work input/output in adiabatic process

[JJJabc]

I have to find the max cycle pressure, max temp, work input and output for an engine.

I have been given the initial air pressure, temp and the volume of the cylinder.

Fuel is added at 2.5MJ/kg

For the air i have Cv, the index (1.4) and an R value of 287 J/kg K (not sure about this value)

I calculated the max pressure using PV^1.4 = const.
For max temp i used PV/T = const.

1) Not sure if I have used the correct method for calculating the pressure and temp

2)Not sure how to calculate the Work input/output. Is the W=PV equation correct?Would this equation work W=(P2*V2 - P1*V1)/n(1.4)-1

 

[jbsteele]

? Where n is the index and 1.4 is the specific heat ratio.For calculating the work input/output, you would need to use the first law of thermodynamics, which states that energy can neither be created nor destroyed, but can only be converted from one form to another. This means that the work done by the engine is equal to the change in the internal energy of the system. The equation for this is W = ΔU. You could then calculate the change in internal energy using the equation ΔU = CvΔT, where Cv is the specific heat at constant volume.