Experimental Investigation of the Effect of Hydrogen Blending on the Concentration of Pollutants Emitted From a Four Stroke Diesel Engine

The problem of pollutants emitted from internal combustion engines becomes increasingly important since it affects directly and indirectly human life on earth through air pollution, global warming, acid rains.. etc. The concentration of these pollutants must be reduced. One approach to reduce these concentrations is by blending hydrogen gas with hydrocarbon fuels used in internal combustion engines. In this paper an experimental research is carried out to study the effect of hydrogen blending. A four stroke air cooled diesel engine is used in this program. The engine is run at different loads, speeds and hydrogen blending percentages. It is found that increasing the blending percentage reduces the emitted concentration of carbon oxides and smoke. However it is found that nitrogen oxides concentration is increased with increasing hydrogen blending percentage due to higher cylinder temperatures. The results showed that 10% hydrogen blending reduces smoke opacity by about 65%, increases the nitrogen oxides concentration by about 21.8% and reduces CO2 and CO concentrations by about 27% and 32% respectively. This trend is found at all tested speeds and loads.