How Can I Compare the Efficiencies of Ideal Diesel, Otto, and Dual Cycles?

[Altairs]

I want to compare the Ideal Diesel, Otto and Dual cycles with constant specific heats. I am interested in knowing the relationship between r (compression) and nth (efficiency). I am unable to determine the common inputs to all three which can give me the efficiency for all the cycles. r with temperature and pressure is an obvious choice. But I also need cut off ratio to calculate diesel and dual cycle's efficiency and it is not there in otto cycle. And I need pressure ratio for otto's efficiency which is not there in the other two cycles. I was wondering if taking a common Qin (heat input) would do ?

Any suggestions please.

 

[Topher925]

I want to compare the Ideal Diesel, Otto and Dual cycles with constant specific heats. I am interested in knowing the relationship between r (compression) and nth (efficiency).

For a simple cold air analysis, you can consult just about any basic thermodynamics text or possibly even wikipedia. For a cold air analysis the efficiency of a otto cycle is a function of the k value of the gas and the compression radio. For a diesel or dual cycle you will need the cut out or cut in ratios. You shouldn't need any Qin for an efficiency calculation.