Experimental and numerical investigation of dual-fuel CI ammonia engine emissions and after-treatment with V2O5/SiO2-TiO2 SCR

Ammonia (NH3) is one of the most promising fuels regaining interest in recent years, as an alternative to fossil fuels. It is often suggested as a more favorable solution than supplying pure hydrogen due to its higher volumetric energy density. In this study a dual fuel CI engine running on ammonia and diesel mixture was tested, as a means to utilize ammonias potential in diesel engines. The injection strategy was port injection for ammonia, where it was mixed with air, and direct injection of diesel oil. A set of different NH3-diesel mixtures were tested. Due to partial substitution of diesel fuel by NH3 the elementary composition of fuel has changed. It increased nitrogen's and reduced carbon's mass in the combustion chamber. Consequently, the exhaust species have also changed. The Fourier Transform Infrared Spectroscopy was used to analyze the composition of flue gas. On top of investigating changes in CO2, CO, HC, NOX, residual ammonia molar fraction was observed. Possibility of using residual ammonia to activate selective catalytic reduction (SCR) system and its effectiveness in different operating points of engine were investigated. As part of the research, a numerical model of operation of the used SCR system was also developed. Results from the experiments have served to validate numerical model. Created model was then used to analyze wider spectrum of operating conditions of the engine and SCR.

Automated summary

This study tested a dual fuel CI engine running on a mixture of ammonia and diesel fuel, aiming to utilize the potential of ammonia in diesel engines. By using the port injection strategy for ammonia and direct injection of diesel oil, a set of different ammonia-diesel mixtures were tested. The composition of the fuel and exhaust species changed due to the partial substitution of diesel fuel by ammonia. The study also investigated the possibility of using residual ammonia to activate the selective catalytic reduction (SCR) system in different engine operating points. The numerical model of the SCR system developed in the research was validated by experimental results.