Effect of Different Benzoylthiourea Additives to Gasoline on Engine Noise and Vibration in a Spark Ignition Engine

This study investigates the effects of dichloromethane (DCM) and benzoylthiourea derivatives (LH1 and LH2) at concentrations of 25 ppm, 50 ppm, and 100 ppm on engine noise and vibration across various load conditions. The results reveal that noise and vibration levels increased with engine load for all fuel blends, with significant variations depending on the additive type and concentration. Adding DCM to gasoline caused slight increases in both noise (up to 1.29%) and vibration (up to 6.14%) due to its higher density and altered combustion dynamics. LH1 consistently increased noise and vibration levels, with the highest increases observed at 100 ppm (6.77% noise and 23.38% vibration at no load), likely due to its volatile nature and destabilizing effects on combustion. Conversely, LH2 significantly reduced noise and vibration, particularly at 25 ppm and 50 ppm concentrations. At 100 ppm, LH2 reduced noise by 1.98% and vibration by 6.85% at full load compared to gasoline, attributed to its superior knock resistance and stabilizing effects on combustion. The findings highlight LH2 as a promising additive for applications requiring reduced engine noise and vibration, particularly at higher loads. In contrast, LH1's tendency to amplify noise and vibration suggests a need for optimization before practical implementation. This study underscores the critical role of additive composition and concentration in influencing engine performance, providing valuable insights for developing fuel blends with improved acoustic and operational characteristics.