Consider the following statements: 1. The air standard efficiency of an Otto cycle is a function of the properties of the working substance (gas) 2. For the same compression ratio and same input, the thermal efficiency of an Otto cycle is more than that of a Diesel cycle 3. Thermal efficiency of a Diesel cycle increases with decrease of cut-off ratio Which of the above statements are correct?
Consider the following statements: 1. The air standard efficiency of an Otto cycle is a function of the properties of the working substance (gas) 2. For the same compression ratio and same input, the thermal efficiency of an Otto cycle is more than that of a Diesel cycle 3. Thermal efficiency of a Diesel cycle increases with decrease of cut-off ratio Which of the above statements are correct? Correct Answer 1, 2 and 3
Concept:
Since all the cycles reject their heat at the same specific volume, process line from state 4 to 1, the quantity of heat rejected from each cycle is represented by the appropriate area under the line 4 to 1 on the T-s diagram.
As is evident from the equation
The cycle which has the least heat rejected will have the highest efficiency.
Thus, the Otto cycle is the most efficient and the Diesel cycle is the least efficient of the three cycles.