MULTIFUEL CLOSED-LOOP THERMAL CYCLE PISTON ENGINE, SYSTEM AND METHOD

A multifuel closed-loop thermal cycle piston engine, system and method. An externally-fired continuous combustion piston-driven engine configured to employ water injection post combustion to maintain a temperature of exhaust gas at a set point to form a closed-loop thermal cycle. A multifuel closed-loop thermal cycle piston engine includes a drive stage, a compression stage separate from the drive stage, the compression stage including a pressure-operated exhaust valve of a compression cylinder, an externally-fired continuous combustion chamber configured to conduct continuous combustion of a nonselective fuel, the combustion chamber comprising a water injection stage succeeding the fuel burner chamber, the water injection stage configured to inject water into the combustion chamber post-combustion, and wherein a quantity of water injected post-combustion is configured to maintain engine exhaust at or below a temperature set point.