Experimental optimization of engine performance of a dual-fuel compression-ignition engine operating on hydrogen-compressed natural gas and Moringa biodiesel

Abstract

Non admixed Natural gas-fuelled diesel engines are usually associated with harsh engine emissions as well as low performances at moderate to high engine loads. However, the use of Moringa biodiesel as additive in hydrogen-compressed natural gas (HCNG) is a viable novel strategy for reducing toxic emissions such as hydrocarbons and nitrogen oxides in CI engines. In this study, five hybrid HCNG–Moringa biodiesel (MB) oil samples labelled A–E were analysed for their abilities to improve the overall performance of a CI engine (Petter PH1W diesel engine). The fuels had a fixed volume by volume hydrogen : carbon ratio of 87:13% respectively, and the HCNG–MB hybrid samples consisted of 0, 5, 7, 10 and 13 %v/v MB for samples A, B, C, D and E, respectively. At higher engine loads (i.e. 58%–100%), the engine performance improved thus giving higher BTEs in the range of 19–33.9% for all the fuel blends relative to the BTE (15.1%–19%) of the unblended HCNG fuel; this confirms the suitability of MB as an additive for improving the brake thermal efficiency of CI engines; there were also reductions in HC, O2, CO2, CO and NOx emissions for all the MB–HCNG fuels relative to the case of the unblended HCNG fuel. At optimum condition, the fuel that gave the best results in terms of the aforementioned engine characteristics is the MB–HCNG fuel blend having 10% MB.