The proposed project combines renewable solar energy and combustion engines. It is proposed to make feasible the use of fuels, which can be produced by utilizing (i) solar energy to electrolyze water and produce hydrogen and (ii) CO2 released by combustion processes to produce high-energy-density liquid fuels, such as alcohols. So far, the major obstacle in the use of such fuels is the toxicity of their exhaust gases. The main goal of the project is to identify specific additives, which will reduce the toxic products, either directly by chemical means or indirectly by modifying the ignition delay. These additives will be identified algorithmically with the CSP method and the resulting findings will be validated by experiments, in which the toxicity of the exhaust gases will be measured. Successful completion of the project will establish a route that will effectively reverse combustion and regenerate fuel from combustion products.