IN SITU VALUATION OF AUTO-IGNITION QUALITY OF FUEL IN COMPRESSION IGNITION ENGINES

A system for an engine to determine in situ under specified conditions the auto-ignition quality of the fuel used in a compression ignition engine is provided. The system may include an ion current sensor. The ion current sensor may access an engine cylinder for obtaining ion current data. A control unit may be in communication with the ion current sensor for receiving the ion current data. The control unit being configured to determine the auto-ignition quality of the fuel based on features of the ion current data.