Evaluating combustion, performance and emission characteristics of CI engine operating on diesel fuel enriched with HHO gas

Abstract

Research of efficient and ecological parameters was carried out with compression ignition (CI) engine using diesel fuel and additionally supplied hydrogen and oxygen (HHO) gas mixture. HHO gas is produced by electrolysis when the water was dissociating. At constant engine‘s brake torque and with increasing HHO gas volumetric concentration in taken air up to 0.2%, engine efficient indicators varies marginally, however, with bigger HHO concentration these parameters becomes worse. HHO increases smokiness, but it decreases NOx concentration in exhaust gas. Numerical analysis of combustion process using AVL BOOST software lets to conclude that hydrogen, which is found in HHO gas, ignites faster than diesel fuel and air mixture. Hydrogen combustion before TDC makes a negative work and it changes diesel fuel combustion process – diesel ignition delay phase becomes shorter, kinetic (premixed) combustion phase intensity gets smaller.