Investigating the role of fuel injection pressure and piston bowl geometries to enhance performance and emission characteristics of hydrogen-enriched diesel/1-pentanol fueled in CRDI diesel engine

This paper deals with the effects of piston bowl geometry (hemispherical bowl, troded bowl, and re-entrant bowl) and fuel injection pressure (200 bar, 220 bar, and 240 bar) with hydrogen-diesel/1-pentanol (B20 (80% diesel and 20% pentanol) + 12 lpm of hydrogen) on the emission, combustion, and performance characteristics of a common rail direct injection diesel engine. Re-entrant bowl outperforms hemispherical and troded bowl in terms of brake thermal efficiency (5.67%) and hydrocarbon (8% reduction) with an increase in the fuel injection pressure (240 bar) at part and full load. However, with the increase in the fuel injection pressure in the re-entrant bowl, a slight reduction in nitrogen oxide emissions (2%) is observed. With an increase in injection pressure in the case of re-entrant bowls, NHRR (net heat release rate), peak pressure (in-cylinder), and ROPR (rate of pressure rises) all rise significantly by 3.4%, 4.2%, and 2.3%. It is found that changing the piston shape and fuel injection pressure simultaneously is a potential alternative for improving engine performance and lowering emissions.