A Review on Hydroxy Gas Enrichment for Internal Combustion Engines

The long-term use of conventional liquid energy sources for internal combustion (IC) engines has its own negative ramifications on the health of living beings and the ecosystem at large. The search for solutions to overcome these implications brings us to one of the domains of research called alternative fuels. Alternative fuels may be used to enrich or fully substitute conventional fuels. In this review, a literature study on the enrichment of a primary fuel using hydroxy gas (HOH) produced from the electrolysis of water is discussed. The experimental evidence shows that HOH induction between 5 and 10 liters per minute (lpm) enhances the results of performance parameters coupled with a decrease in emission levels except for the oxides of nitrogen (NOx). However, this shortfall is nullified using techniques such as exhaust gas recirculation (EGR) and water injection. At high engine loads with 3.5 lpm HOH induction and 0.14–0.29 lpm water induction rate, NO_X emission was observed to decrease by 3–4 times. Other notable advantages with HOH induction include improved combustion characteristics, lower engine vibration, noise, and particulate matter (PM) emission. Studies on thermoelectric devices prove that the HOH producer can be powered by recovering waste engine heat and increasing engine brake thermal efficiency (BTE) by 1.5%. The limited experimental work using HOH induction has necessitated discussion on the optimal production and utilization with other strategies for improved performance and reduced carbon-based emissions and has been a driving factor for further novel research concepts as elucidated in this article.