Effect of Premixed Ethanol Ratio Based on the Same Heating Value on the Atomization of Diesel Fuel Injected in the Cylinder

The objective of this study was to investigate the effect of a premixed ethanol ratio based on the same total heating value in a cylinder on the equivalence ratio distributions and the injected fuel droplet behavior in the cylinder of an RCCI engine. The spray simulation was conducted in two parts. First, we carried out spray validation simulations to determine the spray-influenced factor of the test injector. Next, engine simulations were performed with the spray-influenced factor obtained from the spray validation simulations to investigate the effect of the premixed ethanol ratio based on the same total heating value in a cylinder on the injected fuel atomization and the equivalence ratio distributions. The introduced total heating value was fixed at 595 J based on the lower heating value of diesel, 14 mg. The heating value of the premixed ethanol ratio varied from 0% to 40% based on the same total heating value in the cylinder in steps of 10%. It was revealed that when the premixed ethanol ratio based on the same total heating value in the cylinder was increased, the spray tip penetration value was reduced after 4 deg of diesel was injected because of the short injection duration and the small amount of diesel fuel used. The SMD value was also increased up to 32.58% with an increasing premixed ethanol ratio because of the low kinetic energy of the injected fuel, the short injection duration, the slow evaporation of the injected fuel and the low cylinder temperature.