###### Abstract  
This study aims to investigate the effect of the port injection of ammonia on performance, knock and NOx emission across a range of engine speeds in a gasoline/ethanol dual-fuel engine. An experimentally validated numerical model of a naturally aspirated spark-ignition (SI) engine was developed in AVL BOOST for the purpose of this investigation. The vib two zone combustion model, which is widely used for the mathematical modeling of spark-ignition engines is employed for the numerical analysis of the combustion process. A significant reduction of -50% in NOx emissions was observed across the engine speed range. However, the port injection of ammonia imposed some negative impacts on engine equivalent BSFC, CO and HC emissions, increasing these parameters by 3%, 30% and 21%, respectively, at the 10% ammonia injection ratio. Additionally, the minimum octane number of primary fuel required to prevent knock was reduced by up to 3.6% by adding ammonia between 5 and 10%. All in all, the injection of ammonia inside a bio-fueled engine could make it robust and produce less NOx, while having some undesirable effects on BSFC, CO and HC emissions. spark-ignition engine; biofuel; ammonia injection; carbon-free fuel; engine knock; emission +
Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 3619995161, Iran; [EMAIL_ADDRESS] (F.S. ); [PERSON]DRESS] (S.V.H.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 361999516, Iran; [EMAIL_ADDRESS] (F.S. ); [PERSON]DRESS] (S.V.H.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 361999516, Iran; [EMAIL_ADDRESS] (F.S. ); [PERSON]DRESS] (F.S.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 361999516, Iran; [EMAIL_ADDRESS] (F.S. ); [PERSON]DRESS] (S.V.H.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 361999516, Iran; [EMAIL_ADDRESS] (F.S. ); [PERSON]DRESS] (F.S.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 361999516, Iran; [EMAIL_ADDRESS] (F.S. ); [PERSON]DRESS] (S.V.H.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 361999516, Iran; [EMAIL_ADDRESS] (F.S. ); [PERSON]DRESS] (F.S.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology, Shahrood 361999516, Iran; [EMAIL_ADDRESS] (F.S.V.H.) Footnote †: journal: Medical and Mechtronic Engineering, Shahrood University of Technology,from other major sectors, such as power production, residential and industry sectors, are showing a reducing trend in EU countries, the emissions from transportation have not been reduced yet when compared to the 1990 level, due to an increase in the number of vehicles across Europe. This is also the case for other parts of the world, despite technological advancements mitigating transportation emissions. Shifting from fossil fuels towards cleaner fuels, such as biofuels, has been considered in recent years [8; 9]. Biofuels are produced via different processes, including the conversion of food waste [8]. They can be used as an additive (or secondary) fuel in vehicles for the reduction of CO2 emission [10; 11]. Biofuels have been used for both spark-ignition (SI) and compression ignition (CI) engines [12; 13; 14]; however, most researchers have focused on CI engines. In recent years, due to the excess NOx and particulate matter emissions from CI engines, for transportation applications, a shift towards SI engines is happening even in hybrid vehicles. In spark-ignition engines, ethanol addition to gasoline has been the main application for biofuels [15], with the aim of greenhouse gas emissions reductions. Ethanol blending of 5% (E5) and 10% (E10) by volume with gasoline has been carried out by different countries for about a decade [3]. Additionally, the most recent emissions regulation (Euro 6.2) uses E10.