In this study, the taguchi technique is used to estimate the optimum solution of concentration level for a diesel engine with a blend of diesel / biodiesel using various load and compression ratio. To analyse the optimal process response by a limited number of experimental runs using the application of Taguchi method L9 orthogonal analysis to solve a multiple response optimization problem. In the present analysis, diesel engine parameters were configured in line with the performance and emission characteristics. The aim is to reduce the brake specific fuel consumption (BSFC), Emission such as NOx, HC & CO and to increase Brake thermal efficiency (BTE) limited number of experimental runs. The aim was achieved through experimental investigations, experiment design and Taguchi method. Lemongrass methyl ester with three parameters viz. Blended with diesel (B20, B40 & B60), variable compression ratio (16.5:1,17.5:1 & 18.5:1) and load varied at (0%, 50% and 100%). The objective of the study was to determine the optimum blend of lemongrass biodiesel and diesel oil that would result in a better engine performance along with minimum emission characteristics. © 2023 Elsevier B.V., All rights reserved.