Comparative Analysis of Combustion Process of Dual Fuel Diesel Engine Fueled by Diesel/Hydrogen and Biodiesel/Hydrogen

The paper presents the results of co-combustion of diesel with hydrogen and biodiesel with hydrogen in a compression-ignition internal combustion engine. The results show that for both cases of combustion diesel with hydrogen and biodiesel with hydrogen a noticeable change in combustion phases were achieved. The addition of hydrogen causes the combustion process more efficient what also has a positive effect for thermal efficiency of dual fuel engine and showed an increase in the value of this parameter of 5% compared to diesel or biodiesel. Comparison of combustion process between conventional engine fueled by diesel or biodiesel and diesel with hydrogen or biodiesel with hydrogen shows the differences in character of heat release rate. The premixed combustion phase after addition of hydrogen to base liquid fuel show an increase in maximum value. The combustion stability of the engine described by the COV_IMEP index and the IMEP normal distribution was also assessed. Addition of hydrogen to diesel fuel cause an increase in the stability of the engine run, the opposite trend was observed after addition of hydrogen to biodiesel. The analysis of the exhaust gas emission after addition of hydrogen was also made for tested engine fueled with diesel with hydrogen and biodiesel with hydrogen. The results showed that there was a positive effect for CO, CO₂ and soot emission, opposite effect was observed for NO_x emission and HC emission was not changing in significant range.