Comprehensive performance, combustion, emission, and vibration parameters assessment of diesel engine fuelled with a hybrid of niger seed oil biodiesel and hydrogen: response surface methodology approach

Abstract

The present investigation centered on the application of response surface methodology to assess the engine operating parameters namely performance, combustion, emission, and vibration characteristics of variable compression ratio direct injection single-cylinder diesel engine operating with Niger seed oil methyl ester blend and hydrogen in dual fuel mode. Response surface models were developed using the experimental data of input and output variables. The fuel blend, load, compression ratio, and hydrogen flow rate were considered as input responses while the brake thermal efficiency, brake specific fuel consumption, cylinder pressure and net heat release rate, carbon monoxide (CO), unburnt hydrocarbon, Nitrogen oxides (NOx), smoke opacity, and RMS velocity respectively were considered as the output responses. The input conditions altered were: loads of 29.43 N (3 kgf), 58.86 N (6 kgf), 88.29 N (9 kgf), and 117.72 N (12 kgf), compression ratios of 16, 17.5, and 18.5, and the hydrogen flow rates of 5 lpm, 10 lpm, and 15 lpm. The output information of the test was assessed using response surface methodology (RSM) and the polynomial model (second-request) was created. The experimental values were in good match with RSM predicted values and maintained an R2 value of more than 0.95 for all the test run combinations. Further, all the test points sustained comparatively within the 10% maximum deviation.