Thermodynamic performance study and RSM based optimization of SI engine using sewage sludge producer gas blend with methane

Looking forward to valorizing the waste municipal sewage sludge (SS), the present study aims to simulate SI engine performance using sewage sludge-producer gas (SSPG), and its performance investigation. To do this, initially, the quasi-dimensional thermodynamic model was developed to determine the SI engine performance with dual-fueled SSPG-methane blends. Thereafter, the influence of input variables on engine performance (Power, fuel consumption, and emission) was optimized through response surface methodology (RSM), aiming to enhance performance and minimize emissions. As setting inputs, the start of ignition (SOI), blend fraction, and compression ratio (CR) was taken into consideration. RSM-based optimization reveals that the best-optimized response occurs with operating variables of 13 CR, 10% SSPG blending, and SOI at 34.09° before top dead center (bTDC) for 100 simulation runs. The respective resulting optimized responses were 35.35% ITE, 6.79 bar IMEP, 28.1% BTE, 4.6 kW BP, 5.49 bar BMEP, 12.81 MJ/kWh BSEC, with CO and NO emissions as 0.645 V% and 1967.1 ppm. Lower prediction errors were confirmed with 95% coefficient of determination (R2) and composite desirability of 0.767. The novelty of the present study is in developing simulation modeling and optimizing responses. Overall, this study predicts that the SI engine can perform efficiently with SSPG-methane blend. [Display omitted] •Prognostic of Sewage sludge-based producer gas and methane fuel blended SI engine.•Quasi-D thermodynamic model and RSM has great ability to predict engine behaviours.•The increase in PG ratio decreased Power and NO, but increased CO emission values.•10% PG blend, 13 CR and 340bTDC spark timing were identified as optimal parameters.•The maximum BTE of 30.24% found at 10% PG blend, 13CR and 400bTDC spark timing.