Internal Combustion (IC) Engines and Gas Turbines are the machines built to convert the chemical energy of fuel into mechanical energy via an exothermic reaction, known as Combustion or rapid oxidation. The combustion involves reaction of constituents of fuel with Oxygen.As on date, atmospheric air is considered as techno-economically the best source of Oxygen. However, Oxygen is only a small fraction of the air and thus bulk of the air is a burden on the energy conversion process with consequential loss of operating efficiency of the respective equipment.This Invention entails improvement in operating efficiency of IC Engines and Gas Turbines on enhancing the oxygen contents or Oxygen enrichment of the air supplied to the respective equipment for combustion of the fuel.This enhancement of Oxygen content or Oxygen enrichment of combustion air is accomplished by addition of Oxygen obtained from an Oxygen Generator. Further, this generator is envisaged to be working concurrently with the IC Engine/Gas Turbine and thus providing the oxygen necessary for the enhancement/enrichment on a concurrent basis.This invention is relevant to all types of Internal Combustion Engines and Gas Turbines irrespective of the basic design, capacity, type of fuel or any mixture of fuels used, or the purpose to which the equipment is deployed and is expected to improve the efficiency of respective equipments with consequent reduction in their operating cost and environmental pollution.