Attending that road transport accounts between 15% - 18% of worldwide CO2 emissions, the automotive sector have a deep commitment to mitigate global warming. As a consequence, stricter regulations have been adopted by the European Union and worldwide to reduce that big impact. Approximately, 10% of the energy generated by fuel combustion in the engine is destined to the auxiliaries components activation and the movement of mechanical elements with relative motion between themself. A reduction on that figure or alternatively a mechanical efficiency improvement can be directly translated on target alignment. The aim of this work is developing a model to predict the mechanical and friction losses and its distribution in a 4-stroke DI-Diesel engine and simulating different strategies which increment the engine efficiency. A 1D dimensional model has been developed and fitted in GT-Suite based on experimental results of a 1.6L Diesel engine. Additionally a description of the tribological performance has been realized in different parts of the engine where friction is present. Finally the engine friction maps have been broken down in order to quantify the friction losses produced in the piston-ring assembly, crankshaft bearings and valvetrain.