Thermodynamic Modelling and Experimental Investigation on a CI Engine Operated with Oxy-Hydrogen Gas as the Secondary Fuel

Abstract

Substitution for diesel in CI engines is an immediate need of the hour, considering fuel scarcity and environmental safety. The usage of oxy-hydrogen (HHO) gas from dry cell electrolyser, as a new source of energy, is gaining an increasing interest worldwide, because of its excellent combustion properties and the ease of retrofitting to the existing engine. In the present work, Taguchi’s design of experiments (DoE) is used to optimize HHO gas production. Further, the obtained results were reviewed using grey relational analysis (GRA) and analysis of variance (ANOVA). The operational parametric studies of the optimized electrolyser were conducted. Performance, emission and combustion characteristics with HHO gas as dual fuel in CI engine were also performed. The lubricating oil and deposit study in dual-fuel operation were conducted to understand the effect of HHO gas in engines. The combustion characteristics of a CI engine, operating in dual-fuel mode with diesel and oxy-hydrogen gas, were predicted by a zero-dimensional two-zone model. A double Wiebe function was used to estimate the mass fraction burned (MFB) in the premixed and diffused stages of combustion. The estimated MFB was used to calculate the heat released. The equations were solved in MATLAB®, and Eulerian approach was used to solve the differential equations. The theoretical results of properties such as in-cylinder pressure, heat release rate and cumulative heat release were compared against the respective experimental values, which showed a good concurrence. Also, the average and zone-wise temperatures with respect to crank angle were determined and plotted. The good agreement between the theoretical and experimental values may be attributed to the use of different form factors in the premixed and diffused stages.