Engine Lubrication Oil Aeration

The lubrication system of an internal combustion engine serves many purposes. It lubricates moving parts, cools the engine, removes impurities, supports loads, and minimizes friction. The entrapment of air in the lubricating oil is called oil aeration. Oil aeration can be detrimental to internal combustion (IC) engines. This study attempts to determine a means to reduce the level of aeration in a typical IC engine. Experiments were performed on a motored Ford 3.OL V6 DOHC engine which was capable of reaching speeds up to 8000 rpm. Oil was sampled from the sump in the pump pick up area. Sump temperature, oil volume, and engine speed were continuously monitored. Aeration measurements were made via an x-ray absorption technique using a machine called Air-X. A repeatability and reproducibility (R&R) study was performed initially. This study determined that the measurement technique was sufficiently repeatable within the tolerance of the Air-X machine. Tests were then performed which varied parameters such as engine speed, oil volume, and hardware design. Specifically, multiple designs of the windage tray, an engine component that separates the oil sump from the rotating crankshaft, were tested. Testing revealed that within the tolerance of the Air-X machine, the extent of the windage tray open area has no significant affect on the aeration level. Thesis Supervisor: Wai K. Cheng Title: Professor of Mechanical Engineering