Exam Question

### (a) Calculated Carbon Aromaticity Index (CCAI)
CCAI is an empirical index used to estimate the ignition quality of a residual marine fuel oil. It is calculated from two easily measured properties: the fuel's density and its kinematic viscosity. The index provides a relative indication of the fuel's tendency to cause ignition delay and combustion knock in a compression-ignition engine.
**Significance & Importance:**
* **Ignition Quality:** CCAI is inversely related to ignition quality. A higher CCAI value indicates a higher concentration of aromatic and asphaltenic compounds, which are more difficult to ignite. This leads to a longer ignition delay period.