Separate and combined effects of hydrogen and nitrogen additions on diesel engine combustion

Abstract

Shortage of non-renewable energies, increase in fossil fuel prices and stricter emissions regulations due to high NOx and soot emissions emitted from combustion of heavy diesel fuels by compression ignition engines, has led consumers to use renewable, cleaner and cheap fuels. An investigation has been computationally carried out to explore the influences of hydrogen and nitrogen addition on engine performance such as indicated power and indicated specific energy consumption and amounts of pollutant emissions like NOx, soot, and CO in an HSDI (High-Speed Direct Injection) diesel engine. Optimized sub-models, such as turbulence model, spray model, combustion model and emissions models have selected for the main CFD code. Meanwhile, HF (Homogeneity Factor) has been employed for analysing in-cylinder air-fuel mixing quality under various addition conditions. After validations with experimental data of diesel combustion with a single addition of 4% hydrogen and combined addition of 6% hydrogen + 6% nitrogen, investigations have conducted for modelling mixing and combustion processes with additions of hydrogen and nitrogen by ranges of 2% to 8% (v/v). Results showed that a single addition of H2 increased NOx and decreased CO and soot and improved ISEC and IP. In the case of nitrogen addition, NOx decreased, both CO and soot emission increased and ISEC and IP considerably ruined compared with NDC operation. Based on the results obtained for simultaneous addition of N2 (8% of v/v) and H2 (8% of v/v), NOx and soot emissions decreased by 11.5% and 42.5% respectively, and ISEC and IP improved 25.7% and 13%, respectively. But amount of CO emissions had an increase of 52% should be paid ncecessary attention as a main disadvantage.

Assessment of the impacts of combustion chamber bowl geometry and injection timing on a reactivity controlled compression ignition engine at low and high load conditions

“…For years, lots of efforts have been made to decrease the level of exhaust gas emissions and to enhance the performance of direct injection diesel engines. To achieve this goal, different approaches have been applied such as using alternative fuels )alcoholic, 6,7 biofuels, 8 gaseous 9–11 ), using fuel additives, 12,13 increasing the direct fuel injection pressure, 14,15 changing the nozzle geometry configuration, 16,17 exhaust gas recirculation (EGR), 18,19 varying injection rate and timing, 20–22 pilot-injection, 23,24 post-injection, 25,26 and multiple injection strategies. 27,28 Besides these strategies, various combustion technologies, such as homogenous charge compression ignition, 29 part premixed charge compression ignition, 30 and premixed charge compression ignition, 31 have been proposed and widely investigated to achieve better fuel economy and lower emissions in compression ignition engines.…”

Performance Analysis of a Diesel Engine Within a Multi-Dimensional Framework

“…In this study, advanced combustion model ECFM-3Z [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] has been employed successfully to get more information about the in-cylinder physical events. In addition, calculation on an engine configuration with compression, spray injection, combustion and emission in a Diesel engine were accomplished.…”

An experimental study of the wave effect in fuel equipment using hydrogen additives to diesel fuel

“…An alternative solution to the problem, outlined in [11], does not provide for the addition of hydrogen to the fuel, but uses direct hydrogen supply to the diesel cylinder. At the same time, works [11,12] use from 8 to 45 % of hydro gen with respect to diesel fuel. The use of hydrogen as an additive to the main fuel plays a role only in increasing the energy intensity of the fuel according to the authors of [13].…”