The invention relates to an internal combustion engine comprising a combustion cylinder housing a combustion piston, a compressor cylinder housing a compressor piston, an expander cylinder housing an expander piston, and a crankshaft connected to the combustion piston and the expander piston by a respective connecting rod. The internal combustion engine further comprises a connecting element rigidly connecting the compressor piston and the expander piston such that the compressor piston and the expander piston move in unison.