Eficiência Ciclo Diesel

The Diesel Cycle Efficiency Calculator determines the thermal efficiency of an ideal diesel engine. The Diesel cycle is a thermodynamic cycle that models compression-ignition engines, where combustion occurs at constant pressure. Efficiency is calculated using the formula η = 1 − (1/r^(γ−1))·((α^γ−1)/(γ(α−1))), where r is the compression ratio, α is the cutoff ratio (volume after combustion over volume before combustion), and γ is the specific heat ratio (cp/cv). The result is a value between 0 and 1, which can be expressed as a percentage.

This tool is useful for mechanical engineers, thermodynamics students, and professionals designing or analyzing diesel engines. By knowing the compression ratio and cutoff ratio, you can estimate the maximum theoretical efficiency of the engine, disregarding losses from friction, heat transfer, and incomplete combustion. Real diesel cycles have lower efficiency, but this calculation serves as a reference for project optimization.

To use the calculator, enter positive values for the compression ratio (r, typically between 14 and 25), the cutoff ratio (α, between 1 and 3), and the specific heat ratio (γ, for air about 1.4). The result is instantaneous. Caution: very high α values reduce efficiency; excessively high compression ratios can cause knocking in real engines. The formula assumes an ideal gas with constant specific heats.

The Diesel cycle efficiency is higher than the Otto cycle for the same compression ratio because constant-pressure combustion allows greater gas expansion. However, diesel engines operate at higher compression ratios, which contributes to their superior efficiency. This calculator helps understand theoretical limits and the influence of parameters on performance.