Influence of H2 enrichment for improving low load combustion stability of a Dual Fuel lightduty Diesel engine. (May 2022)

• Record Type: Journal Article
• Authors: Mattarelli, Enrico; Alberto Rinaldini, Carlo; Caprioli, Stefano; Scrignoli, Francesco
• Other Names: Ghandhi J guest-editor.; Günthner M guest-editor.; Novella R guest-editor.
• Is Part Of: International journal of engine research. Volume 23:Number 5(2022)
• Page Start: 721
• Page End: 737
• Publication Date: 2022-05
• Subjects: CFD-3D -- diesel fuel -- Dual Fuel combustion -- hydrogen -- light duty Diesel engine -- low load -- natural gas; Engines -- Periodicals; 629.25
• DOI: 10.1177/14680874211051600
• Languages: English
• ISSNs: 1468-0874

Abstract

Dual Fuel (DF) combustion can help to reduce the environmental impact of internal combustion engines, since it may provide excellent Brake Thermal Efficiency (BTE) combined with ultra-low emissions. This technique is particularly attractive when using biofuels, or fuels with a low Carbon content, such as Natural Gas (NG). Unfortunately, as engine load decreases and the homogeneous NG-air mixture tends to become very lean, the high chemical stability of NG can be a serious obstacle to the completion of combustion. As a result, BTE drops and UHC and CO emissions become very high. A possible way to address this problem could be the addition of hydrogen (H2 ) to the NG-air mixture. In this paper, a numerical study has been carried out on an automotive Diesel engine, modified by the authors in order to operate in both conventional Diesel combustion and DF NG-diesel mode. A previous experimental characterization of the engine is the basis for the CFD-3D modeling and calibration of the DF combustion process, using a commercial software. The effects on combustion stability and emissions of different NG-H2 mixtures (six blends with 5%, 10%, 15%, 20%, 25%, and 30% by volume of hydrogen) are numerically investigated at a low load (BMEP = 2 bar, engine speed 3000 rpm). The results of the CFD-3D simulations demonstrate that NG-H2 blends are able to decrease strongly CO, UHC, and CO2 emissions at low loads. Advantages are also found in terms of thermal efficiency and NOx emissions.