I think I'm doing this wrong

In an internal combustion engine, air at atmospheric pressure and a temperature of about 20 degrees celcius is compressed in the cylinder by a piston to 1/9 of its original volume (compression ratio = 9.0). Estimate the temperature of the compressed air, assuming the pressure reaches 40 atm

ok I'm using 1 atm to be 1.013E5 Pa

I'm using this formula

(P1 V1)/T1 = (P2 V2)/T2

all numbers subscripts
rearanged for T2

T2 = (T1 P2 V2)/(P1 V1)
T2 = ( 293 degrees K * 4.052E6 Pa * (1/9) )/ ( 1.013E5 Pa * 9)

I think the whole compression ratio thing screwed me up...

1 answer

I think you just need to put v2 as (1/9)v1. v1 should just remain as v1. Then you can cancel out the v1 in the equation.