Experimental study of the effect of oxyhydrogen (HHO) electrolyzer installation location on exhaust emissions (CO and HC) in a four-stroke gasoline motorcycle engine
Keywords:
HHO, Electrolyzer, Installation location, Exhaust emission, MotorcycleAbstract
The rapid increase in motorcycle usage in Indonesia has intensified air pollution, particularly from carbon monoxide (CO) and hydrocarbon (HC) emissions generated by carbureted spark ignition engines. One practical retrofit approach to improve combustion efficiency is oxyhydrogen (HHO) gas supplementation. This study experimentally evaluates the effect of HHO addition on exhaust emissions of a four-stroke motorcycle, with emphasis on the influence of installation location at the air filter and intake manifold. Emission tests were conducted at engine speeds of 1500, 2000, 2500, and 3000 rpm using a four-gas analyzer. Baseline measurements indicated HC emissions ranging from 2060.33 to 2218.33 ppm and CO concentrations between 4.20% and 4.33%, reflecting incomplete combustion characteristics. The introduction of HHO reduced emissions at all tested speeds. Air-filter installation resulted in HC reductions of 10.87–63.80% (mean 43.51%) and CO reductions of 68.00–88.34% (mean 77.24%). In comparison, intake-manifold installation yielded higher average HC reduction of 52.86% (47.97–73.63%), while CO reductions were more variable at 21.48–110.02% (mean 14.51%). Statistical analysis confirmed that these reductions were significant at the 95% confidence level. The results demonstrate that HHO supplementation effectively improves emission performance, with installation location determining the dominant reduction in CO or HC emissions.
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