The invention relates to vehicle engines, in particular to improvements to the thermodynamic cycle that forms the operating method for an internal combustion engine. An aggregate-phase thermodynamic cycle consists in sequential and interrelated changes in the thermodynamic parameters of an exhaust gas as a working medium of an internal combustion engine, resulting from the energetic separation of the exhaust gases in a swirl chamber that is incorporated with the engine into a single thermodynamic system to form a single closed volume. The sequential creation of considerable high and low temperatures brings about aggregate-phase changes in the working medium. At the high temperature limit some or all of the exhaust gases are ionized. At the low temperature some or all of the exhaust gases are condensed in a closed volume. This in turn leads to the creation of a stable and considerable vacuum in this closed volume. This vacuum causes a positive working stroke in the operating cycle of the internal combustion engine.