Patent ID: 9534520
Date: 2017-01-03
CPC Classifications: F01M

Claim:
1. A method of heating a volume of oil contained in a sump of an internal combustion engine from a reduced initial temperature to its operating temperature, the sump having side-walls and a bottom, the engine having an oil circulation system suitable for conveying some portion of the oil volume through the engine and thereby heating the oil; the method comprising: employing a metal porous separator located in the sump, the porous separator having generally vertical upstanding walls extending from the sump bottom and having outwardly extending upper walls extending from the upstanding walls to the sump sidewalls, the separator serving to partition the sump volume into a first sump volume at least partially contained within the upstanding walls of the separator and a second sump volume contained between the upstanding and upper walls of the separator and the side-walls of the sump; the porous separator comprising a wire mesh or perforated sheet, the separator being less than about a millimeter in thickness, wherein the separator comprises a plurality of openings with a characteristic dimension of between about 100 and 300 micrometers and has a thickness of between 2 and 3 times the characteristic dimension, the separator partitioning the oil volume into two portions, a circulating portion contained within the first sump volume and selectively accessible by the engine oil circulation system and a contained portion, substantially retained in the sump and contained within the second sump volume, the porous separator having a permeability to oil which increases with increasing oil temperature, the porous separator being shaped to receive oil returning to the sump container from the oil circulation path and to further contain the oil pickup for delivery of oil to the oil circulation path, the contained portion being external to the circulating portion and enclosed between the separator and the sump side-walls and bottom; repeatedly circulating the circulating oil portion through the engine and raising its temperature; the pores and thickness of the separator cooperating to initially limit mixing of the circulating and contained oil portions to control the heat loss from the circulating oil portion to the contained oil portion until the contained oil portion attains a target temperature, less than the operating temperature; and then, the separator gradually promoting mixing of the circulating and contained oil portions by progressively reversing the partitioning of the oil volume to enable the entire oil volume to be accessible to the oil circulation system and capable of circulation through the engine when the contained volume attains its operating temperature.