Abstract: Lubricant filter for internal combustion engines, particularly for motor vehicles, of the screwed-on type, both for full flow and bypass filtering, the latter being obtained by superimposed filter cartridges with separation of the flow of filtered lubricant. The filter comprises an incorporated reservoir for reserve additives to be admitted to the lubricant at an appropriate time to reintegrate the original additives which are degraded or exhausted after a certain period of operation. The reservoir communicates with the rest of the filter through a discharge duct, normally closed by an on-off piston valve actuatable by means of an outer control knob, and through a feed hole normally closed by a check valve. When the on-off valve is opened, with the engine idling, the check valve is opened, too, and the reservoir of the additives is brought into communication with the rest of the filter, thus causing mixing of the additives with the lubricant which is fed directly to the oil sump.

Abstract: A lubricant filter for internal combustion engines, comprising a cup-shaped member containing one or preferably two cylindrical crown-shaped filter cartridges. The opening of the cup-shaped member is closed by a cover from which a tubular member extends into the inner space of the filter cartridges. A container containing a mixture of additives for the lubricant is accommodated in the tubular member and has at least one opening closed by a diaphragm made of a material soluble in the hot lubricant. The cover has an eccentric inlet opening for the lubricant to be filtered and an axial outlet opening for the filtered lubricant and may further have a second eccentric outlet opening for part of the filtered lubricant.