• Multi objective optimisation is adopted to operate the operating parameters with ternary fuel on RCCI engine. • ANOVA, a statistically valid test is used to develop a regression model. • Biodiesel enriched engine resulted in 2.55% higher NHRR and 6.48% higher CP. • HC and NOx emissions decreased by 5.86% and 11.4%, at higher FIP. • Ternary fuel performs effectively at higher FIP. In light of global energy insecurity and other pressing concerns like global warming, stringent emissions, and rapid industrialization, researchers are looking at the potential for alternative fuel research as a fossil fuel substitute. The present research work is carried out to study the influence of injection strategies (i.e., FIP and FIT) by varying the engine load at a constant velocity of 2000 rpm. The effect of several parameters such as engine load, FIT, and FIP on an RCCI engine fuelled with B20/1-pentanol fuel is examined using an L20 orthogonal array for an RCCI engine fuelled with B20/1-pentanol fuel. Various models were constructed and validated with the aid of experimental results. The ideal engine parameters found were 62.06% of engine load, FIP of 438.5 bar, and 27 0bTDC, and under this configuration, the output obtained is as follows: 206.9 ppm, 25.09 ppm, 33.04 J/deg, 29.39% and 2.39 kW for NOx, HC, HRR, BTE and BP emission respectively. Also, the regression model is developed using ANOVA, a statistically reliable test, and the test results suggest that the regression model is acceptable for the following. The following are the R 2 values obtained: NOx − 99.78%, HC– 99.14%, NHRR- 98.5%, BTE-99.93%, and BP-99.96% respectively.