This paper summarizes the research work incorporated in the exploration of the potential of swirling in CI Engine and designing of a new mechanism, particularly at inlet, to deliver it to improve the in-cylinder air characteristics to eventually improve mixing and combustion process to improve the engine performance.The research is concentrated on the measures to be done on engine geometry so as to not only deliver advantage to any specific fuel. According to the CI combustion theory, better engine performance may be achieved with Higher Viscous Fuel by improving the in-cylinder air-fuel mixing by increasing the swirl (rotation of air view from top of the cylinder) and tumble (rotation of air view from front of the cylinder) of in-cylinder air inside the fuel-injected region. The proposed inlet component is embedded with airfoil and is suitably designed after being iterated from four steps. The deciding factors of shape and orientation of these airfoils are height, chord length and number of blades. The preliminary assessment of the proposed component is performed on a CFD code using incompressible Navier-stokes with k-epsilon turbulence modeling. The 3D cold flow IC engine simulation is conducted on COSMOS and ANSYS Fluent. The validation of the results of in-cylinder airflow characteristics from simulations are compared with other related research works.This paper is the first in series of our research on Diesel Engine. The experimental validation of the proposed component is currently going-on and would be presented in the next publication. The results show that the better mixing of fuel is achieved and the concentration of CO and Unburned Hydrocarbons is also reduced.The analysis is done for 5 load variations namely 20%, 40%, 60%, 80%, and 100%; with and without ASD. Figure 17. Kirloskar TAF-1 Diesel Engine