© 2021 Elsevier LtdIn this study, the combustion, performance, and emission results of the HCCI engine under different fuel and engine parameters conditions were examined experimentally and statistically. Engine speed, excess air ratio, and fuel types with different fusel oil concentrations were used as variable parameters. The engine speed was determined as 1000 and 1200 rpm, excess air ratio 1.7 and 2.1, and fusel oil ratio in fuel was determined as 15% and 30%. When the HCCI engine was operated with these input parameters, the effective torque indicated thermal efficiency, maximum pressure increase rate, COVimep, HC, CO, and NOx values were examined. Experiments were carried out in line with the determined experimental series, and the data obtained were analyzed. Optimization has been made to determine the optimum input parameters by inputting the targeted response parameters from the HCCI engine. After the optimization study, it was concluded that the optimum response parameters, engine speed was 1262.44 rpm, excess air ratio was 1.91631, and was obtained by using F30 fuel. Under optimum input parameters, the effective torque is 5.751 Nm, ITE 34.089%, MPRR 7.257%, COVimep 4.009%, CA50 7 ° CA, HC 454.185 ppm, CO 0.0727%, and NOx 0.000169486 ppm.