In the present work, COME-Triacetin additive blends are experimented in lieu of the neat diesel fuel. Pure coconut oil methyl ester (COME) itself as an additive has advantages in the operation of engine. Attention is bestowed upon the reduction of HC, NO, CO2, CO and smoke emissions, and the same is successfully achieved with the 10% Triacetin and 90% COME blend fuel. Vibration on the engine cylinder in three directions and on the foundation were measured and analyzed to elicit information about the nature of combustion. The pressure signatures are tallied with time waves eliminating the time lag in between exciter and the cylinder head vibration. Triacetin being an antiknock fuel, with 10% blend emanated as a best blend with its contribution to reduce cylinder vibration in vertical direction of the cylinder. The time wave resembles attenuated sine wave replete with pure harmonics indicating smoother combustion with lesser engine detonation. By analyzing the measured in-cylinder pressure data and the derived heat release rate, it is concluded that the addition of triacetin increases the ignition delay and the amount of heat release in the premixed combustion duration, but shortens both the diffusive burning duration and total combustion duration. On the emission side, the smoke and other emissions including NO are reduced without any cognizable trade off with other components of the emissions.