The transition toward sustainable energy solutions has become a strategic priority for modern defence organizations. This study evaluates the impact of hydrotreated vegetable oil (HVO) and its blends on the performance and emissions of a compression ignition engine (OM 366 LA II), which represents the mid-range logistics vehicles deployed by the Lithuanian Armed Forces. Numerical simulations were performed using the Diesel-RK software and validated against engine manufacturer performance data, achieving a mean absolute torque difference of 0.64%. The results indicate that increasing the HVO fraction reduces brake specific fuel consumption (BSFC) and nitrogen oxides (NOx) emissions.