In an internal combustion engine, fuel combustion creates heat, with the bulk of the energy transformed into mechanical effort. The residual heat is excluded into the atmosphere. Only 50 to 60% of the heat energy is turned into work; the other 40-50% is squandered as heat, lowering engine efficiency by 20 to 30%. This heat is referred to as waste heat. The infection of the consume gas determines to quantity on heat recovered. EGR technology recovers this wasted heat, saving a large amount of gasoline. The methods include combustion air preheating, boiler feed water preheating, processing water preheating, and space heating. The current paper describes the experimental investigation of a CI engine fitted with an air-to-air warmth exchanger that serves as the air preheater, heating up air from the EGR to the cylinder inlet. The preheated air in the engine intake manifold impacts engine performance and emission control. The preheater boosts the temperature at the inlet by flowing exhaust gas through it. The higher the air flow temperature, the greater the thermal efficiency of the brakes and, consequently, the lower the specific fuel consumption, pollutants, and ignition delay. Preheating the inlet air causes uniform combustion, which minimises engine noise and defines the routine of CI engines and deprived of a preheater.