Investigation of the effect of hydrogen enrichment on the performance, emission, and combustion characteristics of a diesel engine

Abstract

With an aim to partially replace conventional diesel fuel, this work investigated the impact of injecting hydrogen into an intake manifold of a diesel engine on its performance. Due to the benefits of hydrogen fuel, such as its high calorific value and flame velocity, it can be used in a dual-fuel mode of operation with diesel. The experiment was carried out for various engine loads with engine speed maintained constant at 1500. By using a digital volume flow metre, hydrogen was injected at three different volume flow rates, namely 3, 6, and 9 lpm. Engine combustion, emission, and performance parameters were evaluated for different hydrogen flow rates and compared to sole diesel. The result revealed that the brake thermal efficiency of the engine increased, whereas the brake-specific fuel consumption decreased due to hydrogen enrichment. The hydrocarbon and carbon monoxide emissions were lower in dual fuel mode when compared to sole diesel operation under all load situations. On the other hand, Oxides of Nitrogen (NOx) emission increased with hydrogen flow rate and resulted in higher NOx than diesel. Furthermore, hydrogen enrichment increased the values of the peak heat release rate and cylinder pressure by a significant margin from the corresponding values given by diesel fuel. Among the evaluated H2 flow rates, 9 lpm is found to be the best, demonstrating enhanced engine characteristics Due to the benefits of hydrogen fuel, such as its high calorific value and flame velocity, it can be used in a dual fuel mode of operation with diesel. The experiment was carried out for various engine loads with engine speed maintained constant at 1500. By using a digital volume flow metre, hydrogen was injected at three different volume flow rates, namely 3, 6, and 9 lpm. Engine combustion, emission, and performance parameters were evaluated for different hydrogen flow rates and compared to sole diesel. The result revealed that brake thermal efficiency of the engine increased, whereas the brake specific fuel consumption decreased due to hydrogen enrichment. The hydrocarbon and carbon monoxide emissions were lower in dual fuel mode when compared to sole diesel operation under all load situations. Among the evaluated H2 flow rates, 9 lpm is found to be the best, demonstrated enhanced engine characteristics.