This paper deals with the experimental investigation of direct injection compression ignition (DICI) engine runs with multiple biodiesels–diesel blended and neat diesel fuels along with the energy-exergy analysis to evaluate quantitative and qualitative data for determining energy and exergy efficiencies, losses, and exergy destruction. Second-generation biodiesels are utilized to conduct experiments on engine with constant speed and full throttle condition at a compression ratio of 17.5:1. Energy analysis is based on experimental data, and exergy analysis is performed with the help of derived formula using chemical and molecular structures. Variation in the performance, combustion, and emission parameters for B0, B10, and B20 blends reveals that BTE, AFR, η(mech.), η(vol.), CP, and CO decrease with the increase in BSEC, EGT, MGT, RPR, NHR, CO2, HC, and NOx. Energy-exergy analysis shows that the combustion and exergetic efficiencies are maximum for the B20 blend (+87.73%) and (+52.04%) at 2.5 kW and 3.3 kW BPs. Exergy destructed is observed to be three-fifth of total available exergy. Half of the heat supplied is carried away by cooling water while one-third of heat is converted into brake power, and the remaining heat is lost in exhaust gases and unaccounted losses.