Due to the increase in pollution caused by fossil fuels in internal combustion engines, the demand for renewable fuels such as bio- alcohols has increased, so in this study, the focus is on increasing the percentage of pentanol with a combination of other alcohols used in this experiment. Because so far, little study has been done on pentanol. This study was carried out on a water-cooled four- cylinder gasoline engine with different percentages of pentanol, propanol, butanol, and ethanol alcohol combined with gasoline. Fuel compounds in different volume percentages were added to gasoline at 1000, 1500, and 2000 rpm, and the number of pollutants and engine performance were evaluated at each speed. Due to the presence of excess oxygen in the structure of Pentanol, the engine power increases by 61.5 KW. Engine torque increases due to the high latent heat of Butanol and propanol, in the fuel. BSFC improved by 294 N.M compared to pure gasoline due to the high calorific value of alcohols. The pressure of the gases inside the cylinder during combustion and high temperature leads to the production of NOX in the combustion chamber. The lower the amount of Butanol and Propanol in the fuel, the less HC is produced, which can be due to improved combustion quality. The highest amount of HC in the fuel blend No. 2 at 1500 rpm is 2476 ppm. Increasing the combustion temperature due to the presence of alcohols can cause changes in CO. The CO emission also depended on the amount of Propanol and Butanol, which produce more CO in combinations with 10% Butanol and Propanol. The highest average CO2 change compared to pure gasoline is related to the fuel blend No. 1 by 17.37%.
