The concept of the use of heat contained in exhaust gases of internal combustion engines in order to increase the degree of utilization of the energy contained in engine fuels has been examined. It has been suggested to use heat recovered in such a way for carrying out endothermic reactions of the conversion of alternative fuels. Calculated estimations of the thermal effects of possible reactions and the thermodynamic efficiency of the thermochemical recovery of heat contained in exhaust gases for a reversible thermal power-producing cycle have been performed. A comparison between the effectiveness of the thermal power-producing cycle without the implementation of the stage of thermochemical recovery of heat contained in exhaust gases and that with its implementation has been made. It has been concluded that continuing the research effort in this direction would be appropriate. © 2009 Pleiades Publishing, Ltd.