The　development　of　alternative　fuels　is　important　in　the　fight　against　climate　change.　Both　hydrogen　and　ammonia　are　renewable　energy　sources　and　are　carbon-free　combustible　fuels.　In　a　recent　experimental　study,　the　performance　and　emission　characteristics　of　a　spark-ignition　engine　burning　a　premixed　hydrogen/ammonia/air　mixture　were　evaluated.　The　manifold　absolute　pressure　was　adjusted　to　61　kPa　and　the　engine　speed　was　stabilized　at　1300　rpm.　The　difference　between　a　mixture　with　a　2.2%　volume　fraction　of　ammonia　and　a　pure　hydrogen　fuel　was　analyzed　in　comparison.　Specifically,　the　addition　of　ammonia　increased　the　ignition　delay　and　flame　development　periods　and　reduced　the　rate　of　in-cylinder　pressure　rise.　In　conjunction　with　the　ignition　timing　strategy,　the　addition　of　ammonia　did　not　affect　the　engine　performance.　Nitrogen　oxides　emissions　are　increased　due　to　the　addition　of　ammonia.　The　experimental　results　suggest　that　ammonia　can　be　used　as　a　combustion　inhibitor,　which　provides　a　new　reference　for　the　development　of　hydrogen-fuelled　engines.　(C)　2021　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.