Impact of a Novel 2-Chloro-<i>N</i>-((6-methylpyridin-2-yl)carbamothioyl)benzamide Fuel Additive on Efficiency and Emissions in a SI Engine

In this study, a novel compound 2-chloro-<i>N</i>-((6-methylpyridin-2-yl)-carbamothioyl)-benzamide (CMPB) was synthesized and characterized via FT-IR, ¹H NMR and ¹³C NMR techniques. For the first time, CMPB was evaluated as a potential fuel additive in gasoline, dissolved in dichloromethane (DCM), to investigate its effects on the performance and emissions of a single-cylinder, four-stroke gasoline engine under varying load conditions. This work introduces a new class of benzoylthiourea-based additives to internal combustion engine applications, filling a gap in current fuel additive research. Five fuel blends were tested: pure gasoline (G), G + DCM, and G + DCM with 50, 100, and 200 ppm of CMPB. The results demonstrate that CMPB significantly enhances combustion efficiency and reduces harmful emissions, with 100 ppm of CMPB identified as the optimal concentration for most parameters. At 100% engine load, thermal efficiency increased from 20.10% (G) to 21.06% (G + DCM + 50 ppm of CMPB) and 20.54% (G + DCM + 200 ppm of CMPB), while specific fuel consumption (SFC) decreased from 454.50 g/kWh (G) to 387.12 g/kWh (G + DCM + 100 ppm of CMPB), reflecting improved energy utilization. CO and HC emissions decreased substantially with CMPB addition, with CO emissions dropping from 1.42% (G) to 0.88% (G + DCM + 100 ppm of CMPB) and HC emissions reducing from 69 ppm (G) to 40 ppm (G + DCM + 100 ppm of CMPB) at 100% load. Conversely, NO _<i>x</i> emissions increased, with the 100 ppm of CMPB blend producing 1999 ppm at 100% load compared to 2000 ppm for gasoline, indicating a slight reduction. Oxygen emissions (O₂) in the exhaust rose with CMPB addition, reaching 1.61% (G + DCM + 100 ppm of CMPB) and 1.69% (G + DCM + 200 ppm of CMPB) at full load, suggesting leaner combustion. The results highlight the trade-off between reducing CO and HC emissions and increased NO _<i>x</i> emissions due to higher combustion temperatures. The 100 ppm of CMPB blend provided the best balance, optimizing thermal efficiency and fuel consumption while managing emissions effectively. These findings underscore the potential of CMPB as a novel fuel additive to enhance engine performance and environmental sustainability and pave the way for further research aimed at mitigating NO _<i>x</i> emissions through advanced combustion control or after-treatment systems.