Combustion and Emission Characteristics of a Biodiesel-Hydrogen Dual-Fuel Engine

The paper presents the results of co-combustion of biodiesel with hydrogen in a compression-ignition internal combustion engine. The tests were carried out on a stationary engine with constant settings. The paper presents the results of the assessment of the combustion process, combustion stability and exhaust emissions in a dual-fuel diesel engine fueled with biodiesel and hydrogen. It was found that it is possible to replace biodiesel with hydrogen to its energetic share of 38%. The share of hydrogen in the co-combustion process causes a change in combustion phases and reducing the duration of combustion. The increase of the engine thermal efficiency was obtained with the increase of the H-2 share. A different character of heat release rate was obtained compared to a conventional engine. The reduction in the diffusion combustion phase has contributed to a significant reduction in soot emissions. The maximum 38% of hydrogen energy share acceptable by the engine, resulted in a more than 25-times reduction in soot emissions. The combustion stability assessed on the basis of the unrepeatability of the indicated mean effective pressure (COVIMEP) index and also on the basis of the indicated mean effective pressure (IMEP) normal distribution was also analyzed.