As the global need for energy sources grows, more effort is being put into finding alternative fuels for automobiles, such as biodiesel and biomass. There are several approaches available today for enhancing the combustion processes of diesel engines and lowering emissions. Biodiesel is an oxygenated renewable fuel that has been acknowledged as an ecologically sustainable diesel engine alternative. In this paper the experiment was conducted with Lemon grass biodiesel 20 percent blend (LGBD20) with different proportions of methanol blends. The BTE of LGBD20M15 is 31.1%, and LGBD20M20 is 28.2% in way of comparison to diesel and LGBD20 are 30.7% and 29.8% at full load, correspondingly. The CO emission of LGBD20M10 and LGBD20M15 are 0.12% and 0.11%, whereas for diesel and LGBD20 are 0.17% and 0.15% respectively. The NO emissions obtained for LGBD20M10 and LGBD20M15 are 1300ppm and 1068ppm, whereas for diesel and LGME20 are 1260ppm and 1367ppm respectively at final condition. Co and HC emissions dropped as the amount of methanol in the combination has been increased. Thee smoke obtained for LGBD20M10 and LGBD20M15 are 52% and 44% in way of comparison to diesel and LGBD20 are 69% and 62% corresponding at the final conditions. © 2023 Elsevier B.V., All rights reserved.