Fragmentation and mixing of the fuel used in spark ignition engines with air is highly effective on combustion and exhaust emissions. Studies are carried out on fuel systems in order to prepare the ideal air-fuel mixture ratio suitable for different operating conditions of the engine. In this study, ultrasonic fuel system was used as an alternative to the traditional fuel systems used in spark ignition engines. The average droplet diameter of 20-30 µm in the injector fuel system used in spark ignition engines has been realized as 12 µm with ultrasonic fragmentation. The engine was run at ½ constant load at different speeds with ultrasonic, carburetor and injection fuel systems, and exhaust emissions were measured. The maximum values of the measured exhaust emissions for the three fuel systems were examined comparatively. When the ultrasonic fuel system is used, there is a 99% reduction in CO, 60% in HC, 18% in NOx, 10% and an increase in CO2 compared to the carburetor system, 99% reduction in CO, 12% in CO2, and 45% in HC compared to the injector system. It was observed that there was a 55% increase in NOx. In general, it has been determined that the ultrasonic fuel system has a positive effect on exhaust emissions.

The atomization quality has gained importance with the used of injection systems in internal combustion engines. The atomization quality has been increased by raising spray pressures by the way advances in the production technologies of high-pressure pumps and injectors. In the current situation, the spray pressures in Gasoline Direct Injection (GDI) technology have been reached bar levels between 200 and 800. When the pressure level is raised higher than the specified pressure value, it is understood from studies in the literature that the atomization quality is not provided a significant improvement and the production cost increase due to the technology required for high pressure. In this paper, the fuel has been atomized by using Sinusoidal Intertidal Forces (SIF) as another method to improve the atomization quality. In the literature, there is no any study regarding the suitability of using by atomized under SIF of the gasoline fuel used in internal combustion engines. In the application study, the gasoline fuel has been atomized without the pressure by manufactured SIF generator and the droplet images obtained analysis result has been examined by using the image processing method. According to analysis results, it has been observed that the droplets sizes produced with SIF method were similar results to the droplet sizes founded using the GDI method. It has been determined that the smaller droplet sizes can be obtained with lower costs without using pressure thanks to this method and the method can be applied efficiently in internal combustion engines.