In search for clean energy solutions in a global warming era, oxy-fuel combustion systems are promising. In the study, combustion products are calculated, and exergy analysis is done using the proposed multifeature equilibrium combustion model. And the results obtained for oxy-combustion of different fuels at various oxygen fractions are given in comparison with conventional combustion. For validation, the model results are compared with popular combustion calculation tools, GASEQ and CEA. Effect of oxygen content on oxy-combustion exergy analysis is calculated, also considering changes in equivalence ratio and combustion chamber inlet temperature. Moreover, indicating parameters for combustion performance, temperature ratio, chemical exergy, physical exergy, total specific exergy, and exergy destruction are utilized in the calculations elaborately. Changes in combustion product mole fractions are explained for rich and lean combustion regions. And also, specific exergy results are presented. In terms of exergy destruction, oxy-combustion is more advantageous than conventional combustion. It has been shown that exergy destruction in combustion process with conventional air is approximately 1.5 times higher compared with 21% oxy-combustion, both at different equivalence ratios and at different combustion chamber inlet temperatures. Nowadays, environment-friendly, clean energy production systems are growing in numbers. In this concept, exergetic analyses of combustion for different fuels and greener natural gas, compared with diesel, gasoline, and methanol, are given in comparison. Considering four fuel types, advantageous and disadvantageous cases are presented for oxy-combustion at different oxygen fractions and conventional combustion. As a result, diesel fuel is more advantageous than the other three fuel types, in terms of temperature ratio and exergy. Natural gas combustion appears to be disadvantageous in terms of specific exergy and temperature ratio, but it is the most advantageous in terms of exergy destruction. Consequently, distinctive comparison is done for oxy-combustion and conventional combustion, determining positive and negative effects for different fuels.