Abstract

<div class="section abstract"><div class="htmlview paragraph">The combustion of hydrogen (H<sub>2</sub>) as a fuel is attractive due to its zero-carbon nature and combustion-enhancing properties when used to supplement other fuels. However, the challenge of using H<sub>2</sub> as a fuel for transportation applications is the difficulty of onboard storage. One solution to this is to crack onboard stored ammonia (NH<sub>3</sub>) into H<sub>2</sub> which can be supplied to the combustion chamber. However, the reforming process is not always 100 % efficient which can lead to the presence of NH<sub>3</sub> in the combustion process. The presence of NH<sub>3</sub> can influence engine performance, combustion and emissions. Therefore, this experimental study reports the differences in engine performance between H<sub>2</sub> and NH<sub>3</sub> reformate mixtures (H<sub>2</sub>/NH<sub>3</sub>/N<sub>2</sub>) added to gasoline in a dual-fuel engine setup under both stoichiometric (λ=1.0) and lean-burn (λ>1.0) operating conditions in a spark ignition (SI) engine. In this study, gasoline was used as the main fuel, with the H<sub>2</sub> and NH<sub>3</sub> reformate blends studied having energy substitution ratios ranging from 0% to 23%. The results showed that the use of H<sub>2</sub> and NH<sub>3</sub>/H<sub>2</sub>/N<sub>2</sub> mixtures reduced carbon-based emissions. However, there was an increase in nitrogen-based emissions compared to gasoline with increased H<sub>2</sub> and NH<sub>3</sub> content.</div></div>