a continuous combustion system for an internal combustion engine includes a reaction vessel external to the engine cylinders . the reaction vessel contains a combustion chamber for sustaining continuous combustion of an air fuel mixture during the operation of the associated engine . the reaction vessel contains an incoming air chamber and an exhaust gas chamber that are each in communication with the combustion chamber . injected fuel vapor is mixed with scavenged exhaust gas for pre - heating and with compressed air from each cylinder provided during the compression stroke of each piston . the compressed air and fuel vapor mixture sustains the ignited combustion continuously , while exhaust gas is fed to the cylinders to provide working fluid to the engine during the power stroke of each piston . a valve mechanism is provided to control the flow of air from and working fluid to the cylinders at the appropriate times in order to sustain operation of the engine .