A novel method of increasing the engine efficiency by choosing a better design of combustion chamber and maximizing the  fuel savings is reported here. In this work, an attempt  is made to inject the diesel at a temperature higher than room temperature inside the combustion chamber of a direct injection diesel engine. To overcome the tedious experimental task, a 3-D Computational Fluid Dynamics (CFD)  approach is followed to study the droplet and spray characteristics. The CFD study involves the investigations on combustion and pollutant formation by injecting n-dodecane at specified temperatures of 313 K, 353 K and 393 K. The validation of CFD results with the experiments is accomplished after the optimal spatial and temporal steps of discretization are found out. At the fuel injection temperature of 40 deg C, advancing the injection timing from 6 deg bTDC to 20 deg bTDC yields an increase in cylinder peak pressure from 79.8 bar to 90.9 bar. At an elevated fuel temperature of 120 deg C, the advancement of injection timing from 6 deg bTDC to 20 deg bTDC contributes to an increase in peak pressure from 81.2 bar to 96.9 bar by 19.7 %. This additional increase of 6.1 bar, achieved by heating the fuel from 40 deg C to 120 deg C increases the combustion efficiency, lower soot emissions but yields slightly higher NO_x emissions. Temperature contours at TDC indicates increasing trend with the advancement of injection timing and increase in the injection fuel temperature.