A split cycle internal combustion engine includes a compression cylinder accommodating a compression piston configured to provide compressed working fluid; and a combustion cylinder accommodating a combustion piston. The combustion cylinder is coupled to the compression cylinder to receive compressed working fluid therefrom, and wherein the combustion cylinder comprises: (i) an inlet valve configured to control intake of compressed working fluid into the combustion cylinder, and (ii) an outlet valve configured to control exhausting of fluid from the combustion cylinder, and a controller configured to change the position during the engine cycle at which the inlet and/or outlet valves open to switch operation of the engine between an active mode and an engine braking mode.