Impact of Hydrogen Enriched Air and Ethanol-Diesel Fuel Blends on Combustion, Performance and Emission behaviour of CI Engine

Abstract

The rapid depletion of fossil fuels and harmful tile pipe emissions form internal combustion engines at an alarming rate make the finding for alternative fuels to power the engines. This article investigates the diesel engine capability by the combined effects of ethanol and diesel fuel blending and hydrogen enriched intake air on the performance, combustion, and emission characteristics of 4 - stroke diesel engine. These experiments were conducted using three different fuel configurations such as 20% ethanol-80% diesel blend (E20D80), neat diesel (D100), and ethanol diesel blend (E20D80), supplemented with hydrogen enriched air (E20D80+H₂6LPM). The hydrogen was supplied to engine at constant flow rate of 6 LPM through manifold along with air. Three distinct fuels were used in the engine, and its performance, emissions, and combustion characteristics were assessed under load conditions ranging from 0% to 100%. Hydrogen enrichment of the intake air improves the combustion efficiency of ethanol by accelerating flame speed and enhancing thermal conversion, offsetting ethanol’s lower calorific value. A peak in-cylinder pressure of approximately 69 bar was achieved, indicating more effective combustion. CO emissions decreased significantly under part-load conditions due to improved oxidation kinetics. Ethanol’s high latent heat of vaporization helped maintain NOx emissions at levels comparable to diesel 1023 ppm. However, a slight increase in smoke emissions was observed with hydrogen addition, possibly due to richer local equivalence ratios and altered combustion dynamics.