Question

For the same compression ratio and heat rejection, the thermal efficiency is:

• A. \(Otto>Dual>Diesel\)
• B. \(Diesel>Dual>Otto\)
• C. \(Dual>Diesel>Otto\)
• D. \(Dual>Otto>Diesel\)

Hint:

The efficiency of cycles increases as the combustion process becomes closer to constant-volume, as seen in the Otto cycle.

Answer 1

The Correct Option is A

Step 1: Understand the efficiency of different cycles.
The thermal efficiency of an engine cycle is influenced by the type of combustion process. The Otto cycle, with its constant-volume combustion process, is generally more efficient than the constant-pressure combustion of the Diesel cycle. The Dual cycle lies in between, as it uses both constant-volume and constant-pressure processes.
Step 2: Efficiency comparison.
For the same compression ratio and heat rejection, the Otto cycle is the most efficient. The Dual cycle is next, and the Diesel cycle is the least efficient due to its lower compression ratio and constant-pressure combustion process.