Method and device for improved exploitation of the thermal energy of combustion engines

The method involves selectively supplying working medium to a heat exchanger (2) for transferring heat energy of hot exhaust gases to the medium for cooling components of an internal combustion engine (1) and for simultaneously over-heating the medium and/or to a steam line (22a) below partial bypass of the heat exchanger, via a switchable direction control valve (17). The steam line is arranged downstream to the heat exchanger in a flow direction of the medium. The medium is selected from water, ammonia, ethanol, methanol, carbon dioxide or a solution of gasoline and oil. An independent claim is also included for a device for improved utilization of heat energy of an internal combustion engine, comprising an expander.