The CCAI (Calculated Carbon Aromaticity Index) methodology estimates the ignition quality of residual marine fuels. It uses the fuel’s density (in kg/m³) and kinematic viscosity (in cSt) to calculate an index value that indicates how easily the fuel will ignite in a marine engine.
The formula applies a double logarithmic function to the viscosity and adjusts for density to reflect the fuel’s aromatic content, which affects ignition delay. Higher CCAI values suggest poorer ignition quality, while lower values indicate better combustion performance. This method provides a quick, empirical assessment without needing lab-based ignition tests.
