In a diesel engine, the fuel-air mixture is introduced at room temperature and burned inside the cylinder. After the fuel is burned, the combustion products are discharged at atmospheric pressure and high temperature. The heat generated during the combustion of fuel is partially converted into work to drive the car (or any load) and remaining is wasted to the atmosphere through exhaust gas and coolant. The heat generated by combustion of fuel is converted into the work because of the pressure created by the combustion process. The efficiency of the engines is between 20 and 30 %. This paper highlights provision for incorporating a heating vessel for preheating air before admitting into the cylinder of a diesel engine. The heating vessel comprises heating elements for heating the air flowing past said heating element, and a body for mechanically holding and electrically contacting said heating element. The effect of preheated air on standard diesel fuel engine indicated a good result on emission control. NOx and CO emissions at intake air temperature of 55 °C were less when compared at intake air temperature of 32 °C. Higher inlet air temperature causes lower ignition delay, which is responsible for lower NOx formation. Uniform or better combustion is occurred due to pre-heating of inlet air, which also causes lower engine noise. Easy vaporization and better mixing of air and fuel occur due to warm up of inlet air, which causes lower CO emission.