In the fast moving world, hydrocarbon based fuels have become significant for a century’s development.

The fuels derived from crude oil are critical source of energy for fueling vehicles. However, crude oil based fuels are non renewable. The present investigation of using hydrogen was carried out in a direct injection diesel engine having a compression ratio of 17.5: 1 and a capacity of 5.9 kW at a rated speed of 1800 rpm. In this investigation, the hydrogen was fed to the engine through the inlet manifold along with intake air during suction stroke of the engine. In order to maintain safety, the flame trap and flame arrestor were also used in the experimental setup. The results shows that there is an increase in brake thermal efficiency of the engine and reduction in carbon monoxide emission when, the hydrogen is used as a dual fuel, in the operation of the diesel engine.