Performance-emission-stability mapping of CI engine in RCCI-PCCI modes under varying ethanol and CNG induced reactivity profiles: A comparative study through experimental and optimization perspectives

The study showed the synergistic benefits of split injection strategies on the emissions, performance and stability of an existing diesel engine fueled with biodiesel-CNG/ethanol. The response parameters of the coefficient of variance of indicated mean effective pressure (COVIMEP), exergy efficiency (XRG), equivalent brake specific energy consumption (EQ_BSEC), nitrogen oxide (NOx), unburned hydrocarbon (HC) and Soot elements were experimented and analyzed. The study performed a comprehensive design-of-experiment (DoE) to determine the operational limits and parametric space for design. It aims to find optimisation by measuring the rate of variability and standard estimation errors through model development on the response surface methodology (RSM) platform. In the DoE-RSM configuration archetype, this study attempts to create a space utilising several robust fitness metrics. The split injection has proven its ability to mitigate lower emissions, and better efficiency requirements from biodiesel fueled experimental studies. The optimum predicted value of highest CNG energy share provides noticeable improvement on XRG, EQ_BSEC, COVIMEP, NOx and HC by 5.51%, 17.58%, 24.73%, 61.49% and 28.20% respectively. However, the optimum predicted value of highest ethanol energy share provides improvement on EQ_BSEC, COVIMEP and HC by 15.83%, 1.07% and 68.05%, respectively. (C) 2022 Elsevier Ltd. All rights reserved.