Experimental investigation of variable compression ratio and ignition timing effects on performance, combustion, and Nox emission of an ammonia/hydrogen-fuelled Si engine

Abstract

In the present experimental study hydrogen-assisted ammonia combustion strategy is used in a SI engine with variable ignition timings (18ºCA bTDC to 32ºCA bTDC) and wide-open throttle conditions, CR changes (14–16) at 1400RPM and 1800RPM. This article aims to optimize ignition timing to boost efficiency and power without knocking. It has been established that ammonia/hydrogen fuels are a clean energy source capable of reducing pollution caused by undesirable emissions. The results revealed that increasing the CR from 14 to 16 increased brake power, brake thermal efficiency, NOX, cylinder pressure, and net heat release rate by 36.82%, 25.11%, 30.21%, 10.35%, and 9.53%, respectively. CA10-90 and EGT, on the other hand, are reduced. Increased speed reduces volumetric efficiency by 9.5% at 1800 RPM. In each CR, 28ºCA bTDC ignition timing and 21% hydrogen energy fraction performed well, which can be observed. Hence, the experiment results indicate hydrogen can be used as a combustion promoter, establishing a new standard for developing ammonia-fuelled engines.