1. The problem statement, all variables and given/known data In a diesel engine air is adiabatically compressed to autoignition temperature (287oC) of diesel. Given C/nR=2.78 for air, and the room temperature is 27oC, what is the compression ratio where diesel vapor is added for ignition. 2. Relevant equations PV=nRT PV=NkT C=(dU/dT) 3. The attempt at a solution I'm just frustrated with this review problem and think I may be over thinking it but I am not given an initial pressure or volume and so I am not sure where to even start with this problem. Could someone please give me a push in the right direction.