Oil circulation circuit for internal combustion engine, and method of circulating lubricating oil

Abstract

To control the viscosity of oil circulating in a forced-oil circulation path of an engine, oil is conducted to a receptacle located, for example, within the oil pan of the engine or in communication with the overflow outlet stub (14) of the oil pump (3), and oil is conducted from this intermediate receptacle, for example in form of a pan (6) in two parallel paths. One of the paths conducts the oil directly to the suction inlet of the pump after, however, having to overcome a static pressure, for example by flowing over an elevated weir, notch, or through an overpressure valve; the other path is through a flow resistance element (7), for example a constricted tube, a lamella package, or the like, and then to the cooling portion of the oil pan, remote from the suction inlet of the pump. If the oil is cold, little of the cold and hence high-viscosity oil can flow through the flow restriction path, and back-pressure will build up, so that oil can flow through the overflow, weir, or the like, directly to the pump inlet, for rapid heating by the operating temperature of the engine; as the oil thins, and the viscosity drops, more oil will flow through the oil flow resistance path. If the oil is excessively diluted, it will be rapidly closed, since no back-pressure will develop and all the oil will flow through the second path, and be cooled by the oil pan.

Dependencies are inferred from the claim text.