Abstract
Post-injection has been attracted attention as the Diesel Particulate filter regeneration method. However oil dilution that occurs when fuel spray impinges lubricating oil film on cylinder liner is an issue which cannot be ignored. Because oil dilution is leading to deterioration of sliding properties of piston and thermal efficiency, there is need to clarify spray impingement behavior on lubricating oil film. Therefore, in this research, we focus on the fuel dilution phenomenon by post injection and aim for modeling. Then, the critical weber number was measured to make it possible to judge whether or not the fuel droplet impinges on lubricating oil film splash or deposition. As a result, it was found that the fuel droplet impingement behavior on lubricating oil film is classified into three behaviors by two critical weber numbers. First, WcrP = (272 + 11600 δnon1.29)La0.01, second, WecrS = (211 + 2255 δnon1.05) La0.05, La = ρο σο din / μ ο2, Here, ρο is density of Lubricating Oil, σο is surface tension of Lubricating Oil, μο is viscosity coefficient of engine oil, and La is Laplace number.
