Performance and emission optimization of CI engine fueled with coconut shell–based producer gas and diesel by using response surface methodology

Producergas or syngas generation from biomass gasification reveals one of the pronounced perspectives to substitute conventional fossil fuel. In the present experimental studies, performance, emission, and fuel consumption of VCR engines run with diesel and coconut shell–based producer gas (PG) with varying load, CR, and gasification equivalence ratio (GER) have been performed. Apart from this analysis, the response surface method has been applied to optimize engine operating inputs like CR, load, and gasifier ER to improve the performance by maximizing brake power (BP) and brake thermal efficiency (BTE) and minimizing brake specific fuel consumption (BSFC) and exhaust emission (CO, UHC, CO2, and NOx). In the experiment, total 48 experimental data set was executed for the RSM-based optimization and ANOVA sensitivity test. The formation of regression models using ANOVA showed high accuracy in forecasting output response variables with a confidence interval of 95%. The RSM predicted a good relationship between the range of inputs and output parameters with high accuracy. The coefficient of determination of the RSM value was found to be equal to 0.9520, which shows the high accuracy level in the relationship between statistical-based prediction and experimental values. As per the results obtained by using RSM optimization, the best operating conditions of the engine were obtained to be 0.12 gasification equivalence ratio and 16 compression ratio with 12 kg engine load. The optimum responses predicted under these operating parameters were obtained equal to 3.5 kW, 26.41%, 0.48 kg/kWh, 0.0042% (vol%), 15.15 (ppm), 1.27 (vol%), and 2.94 ppm for BP, BTE, BSFC, CO, UHC, CO2, and NO respectively. Thus, RSM is a useful approach for assessing and improving the performance and exhaust emission of a CI engine powered with diesel and PG corresponding to optimized input variables.