Impact of HHO produced from dry and wet cell electrolyzers on diesel engine performance, emissions and combustion characteristics

Water electrolysis produces HHO gas by using sodium hydroxide catalyst. Dry and wet cells designs are applied producing the gas flow rates at 0.5 and 0.75 LPM, respectively. Tests are done in a diesel engine at engine speed variation and full load. Performance, combustion characteristics and emissions investigations of diesel engines using HHO gas from dry and wet cells are performed. HHO gas addition enhances the brake thermal efficiency by 2 and 2.5% but the exhaust gas temperature highest decreases for dry and wet cells are 8 and 10%, respectively about diesel oil. The maximum decreases are evaluated as for CO (15, 22%), HC (31, 39%), NOx (35, 42%) and smoke emissions (25, 35%), respectively for dry and wet cells about diesel fuel. The improvements in cylinder pressures are 5 and 10%, respectively and the heat release rate enhancements are 4.5 and 6.5%, respectively about pure diesel for dry and wet configurations. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Water electrolysis produces HHO gas using sodium hydroxide as catalyst. Tests on diesel engines showed that HHO gas addition increases brake thermal efficiency, reduces exhaust gas temperature, decreases CO, HC, NOx, and smoke emissions, enhances cylinder pressures, and improves heat release rates compared to pure diesel.