METHOD OF OPERATING A HYBRID AMMONIA-DIESEL COMPRESSION IGNITION PROPULSION SYSTEM AND/OR POWER GENERATION SYSTEM AND CONTROLLING THE POWER OUTPUT AND EMISSIONS THEREOF

A compression ignition engine system includes: a compression ignition engine which is configured for using ammonia as a primary fuel source and a compression ignition engine fuel as a secondary fuel source; and a control system operatively coupled with the compression ignition engine and configured for at least partially controlling a use of the ammonia and the compression ignition engine fuel by the compression ignition engine, the compression ignition engine system having an absence of an exhaust gas recirculation system or an absence of an exhaust gas recirculation system that functions.