A free-piston engine with a linear power generator and a least one engine arrangement including: - a linear chamber with a longitudinal direction and at a first end with a first housing with a first reaction chamber, a first chamber port and a first intermediate chamber port, and at a second end with a second housing with a second reaction chamber, a second chamber port and a second intermediate chamber port, and between the first and second housing an intermediate housing with an intermediate chamber around which is provided - a coil arrangement with at least one coil in connection with at least one first magnetic flux arrangement; - a piston with a first working face facing the first end and oppositely a second working face facing the second end, the piston provided for a linear reciprocating movement in the linear chamber, the piston having at least one second magnetic flux arrangement for interacting with the at least one first magnetic flux arrangement; - where the first reaction chamber has a first chamber end face facing the first working face of the piston, and the second reaction chamber has a second chamber end face facing the second working face of the piston; and wherein the first chamber end face in the first housing has a connection to a first actuator for a first displacement in the first reaction chamber, and the second chamber end face in the second housing has a connection to a second actuator for a second displacement in the second reaction chamber.