FILTER FOR LUBRICANTS OF INTERNAL COMBUSTION ENGINES, WITH A RESERVE OF ADDITIVES

Abstract: Filter for lubricants of internal combustion engines particularly for motor vehicles, of the screwed-on type, both for total continuous (full-flow) filtering and double (bypass) filtering, the latter being obtained by superimposed filter cartridges (3, 4) with separation of the flow of filtered lubricant. The characteristics of the filter is that it comprises an incorporated reservoir (8, 108) for the reserve additives adapted to be admitted to the lubricant at an appropriate moment to reintegrate the original additives which are degraded or exhausted after a certain period of operation. The reservoir (8; 108) communicates with the rest of the filter through a discharge conduit (2; 121), normally closed by an on-off piston valve (32;132) actuatable by means of an outer knob (35; 135), and through a feed hole (24; 124) normally closed by a check valve (25; 125). 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 obtaining mixing of the additives with the lubricant which is fed directly to the oil sump.

Description: The present invention relates to a filter for lubricants of internal combustion engines, particularly for motor vehicles, provided with a reserve of additives. More particularly, the invention relates to a filter of the screwed-on type, in which the additives of the reserve can be introduced into the flow of the lubricant when desired. Some types of filters for lubricants of internal combustion engines are known which contain mixtures of additives designed to integrate or replace the additives which are originally present in the lubricant and which after a certain period of operation are normally consumed or degraded. The prevalent conception of these filters with regard to the introduction of additives is such as to provide a gradual and prolonged introduction of the additives into the flow of lubricant. This is achieved, for example, by impregnating or coating the filtering material with little soluble additives (U.S.A. Patent No. 2,310,305); or by stocking the additives in a container having permeable walls exposed to the flow of the lubricant (U.S.A. Patent No. 3,749,247); or by providing a solid mix of additives accommodated in the filter in direct contact with the flow of lubricant (U.S.A. Patent No. 4,075,097). A filter designed by the Applicant himself and described in U.S.A. Patent No. 4,265,748 on the other hand, is based on a different principle of introduction of additives, namely on the complete and sudden introduction of the additives into the flow of the lubricant only after a certain period of operation when the original additives are supposed to be completely consumed or degraded. This is obtained by placing the additives in a container inside the filter, provided with at least one wall that is slowly soluble in the lubricant so as to produce - when the wall has been completely dissolved - the complete and immediate introduction of the additives into the lubricant. The moment of introduction is determined in advance as a function of the life of the lubricant on the basis of the chemical nature and the physical structure of the soluble wall of the container. The filters of the type with slow introduction of the additives are not considered satisfactory for optimum duration and quality of modern lubricants as these lubricants - when they are brought into commerce - already contain additives in such an amount as to ensure a good performance over a long period of time so that it is neither nor correct to increase the level of introduction of additives from the very beginning even if only in a gradual manner. On the other hand, the filter of the U.S.A. Patent No. 4,265,748 mentioned above, although it is based on a more correct principle of introduction of additives, does not permit to determine exactly the moment of introduction of the additives into the flow of lubricant as this moment, in addition to the characteristics of the soluble wall of the container, also depends on the operating conditions, on the state of the engine and on other factors which cannot be exactly ascertained or determined in advance. It is the object of the invention to eliminate or reduce the disadvantages of the above-mentioned filters by providing a filter for lubricants of internal combustion engines, particularly of motor vehicles, which permits to introduce a reserve of additives into the flow of lubricant in the moment desired by the user, independently of the mileage covered and of the chemical and physical characteristics of the additive or of their container. These and other objects and advantages of the invention, which will become apparent from the following description, are achieved by a filter for lubricants of internal combustion engines, particularly for motor vehicles, comprising a bowl containing at least one filter cartridge, a cover with a plurality of eccentric inlet apertures for the lubricant to be filtered and two outlet apertures for the filtered lubricant, an axial one and another intermediate one, a sleeve which extends axially from said cover in the direction towards the bottom of the bowl, sealing means between the outer surface of said sleeve and said filter cartridge for separating the flow of filtered lubricant and feeding it to said outlet apertures, characterized in that incorporated in said bowl is a reservoir for lubricant additives, communicating with the rest of the filter by means of a feed hole normally closed by a check valve, and by means of a conduit normally closed by an on-off valve actuatable, if desired, to mix the additives contained in said reservoir with the lubricant flowing in the filter. The invention will now be described with reference to the accompanying drawings, given by way of a non-limiting example, and in which: Fig. 1 is a view in axial section of a first embodiment of the filter according to the invention, constructed as a filter with double filtering; Fig. 2 is a partial view in axial section of a modified portion of the filter of Fig. 1 in a different operating arrangement; Fig. 3 is a view in axial section of a second embodiment of the filter according to the invention, again constructed as a filter with double filtering; Fig. 4 is a view in axial section of a third embodiment of the filter according to the invention, constructed as a filter with continuous total filtering; Fig. 5 is a view in axial section of a fourth embodiment of the filter according to the invention, again constructed as a filter with continuous total filtering. With reference to Fig. 1, the filter according to the invention is of the bypass type with double filtering and comprises a bowl 1 of deep-drawn sheet metal with a conical bottom and closed upwardly by a cover 2 - made substantially as described in the U.S.A. Patent No. 4,265,748 of the same Applicant - and two axially superimposed filter cartridges 3, 4, the first one adapted to effect rough filtering on the major portion of the flow of lubricant and the second one adapted to effect a fine, i.e. more intense filtering on only a portion of the flow of lubricant. The entry of the lubricant into the filter takes place in the direction of the arrows A through a series of eccentric holes 5 from which the lubricant is admitted to the outer zone 9 of the filter cartridges to then traverse them radially towards the interior. An axial sleeve 10 firmly secured to the cover extends from the latter up to the height of the rough filter cartridge 3. The upper and lower bases of both the filter cartridges are closed so that the lubricant can traverse the filter elements only in the radial direction. An annular gasket 12 is accommodated between the sleeve 10, the lower base of the upper cartridge 4 and the upper base of the lower cartridge 3 to separate the flow of the lubricant filtered in the two cartridges. In this manner the lubricant subjected to rough filtering is conducted into the interior of the sleeve 10 and then to the axial outlet hole 6 whereas the lubricant subjected to fine filtering rises in the gap 15 - defined between the sleeve 10, the cartridge 4, the gasket 12 and an upper gasket 13 placed between the lower base of the cartridge 4 and a shoulder 8 of the sleeve 10 - and leaves the filter through the intermediate outlet hole 7. The axial hole 6, which is threaded to permit the filter to be mounted by screwing on (filter of the spin-on type), is in communication with the engine whereas the intermediate hole 7 leads to the oil sump, not shown. Accommodated in appropriate seats above the cover 1 are two circular gaskets 16, 17 for sealing to the engine block and for separating the lubricant leaving the filter from the lubricant entering it. Below the lower filter cartridge for rough filtering according to the invention there is arranged a circular wall 20 which separates the lower portion of the bowl 1 from the upper portion where the filtering takes place, so as to form a reservoir 8 for a reserve of additives to the lubricant. The wall 20 is mounted, by means of a rubber ring 11 inserted in a central hole thereof, on an axial conduit 21 formed integrally with the sleeve 10 into which it penetrates to a certain length and to which it is connected by an elbow 22 opening into the gap 15. A circular gasket 23 seals the outer edge of the wall 20 against the inner surface of the bowl, but nevertheless permits the wall to make small axial movements due to the oil pressure existing thereabove. Further, a hole 24 is provided in the wall 20, this hole being normally closed by a one-way check valve 25 which can be opened by a difference in pressure, as will be explained hereinafter. Accommodated in a central recess 27 above the wall 20 is a spiral spring 28 adapted to keep in position both the filter cartridges in the interior of the bowl. The spring is upwardly received in a recess 14 of the filter cartridge 3 in the centre of which there is provided a hole in which a second rubber ring 11' is arranged for sealing against the conduit 21. Provided on the bottom of the lower filter cartridge is an aperture 29 which is closed by a relief valve 30, as is known in the art, to ensure the flow of the lubricant even in case of clogging of the filter. The lower end of the conduit 21 is normally closed by an on-off piston valve 32 comprising a body 33 of larger diameter, which extends up to the bottom of the bowl where it is received in a seat 34 the lower portion 34′ of which is threaded and engages to cylindrical lower portion 33′ of the body 33 which is likewise threaded. The lower portion 33′ of the body 33 is formed integrally with a knob 35 located outside the bowl and adapted to translate axially to unscrew the entire body 33. In this manner the small piston 32 can be removed from the conduit 21 and thus the reverse of additives can be brought into communication with the portion of the filter where filtering takes place, and vice versa. Appropriate gaskets 36, 36′ ensure sealing of the small piston 32 in the conduit 21 and of the body 33 in the seat 34, respectively. A ring 37 abutting the seat 34 limits the path of the body 33 during unscrewing and prevents the small piston 32 from being drawn out of the conduit 21. A perforated cup 38 is fitted, by means of an axial hole made in the bottom 38′, on the piston 32 and engages the abutment 39 defined between the piston 32 and the body 33 of larger diameter. This cup serves to limit the axial movement of the wall 20 produced by the pressure of the lubricating circuit acting above the wall. The operation of the filter described above, as far as double filtering is concerned, is not different from the filter of U.S.A. Patent No. 4,265,748. But as far as the addition of additives is concerned, the operation is as follows. After a certain period of time, or after a certain mileage has been covered after having last changed the filter or the lubricating oil, and anyhow at the choice of the user, one proceeds to reintegration of the additives by unscrewing the knob 35. This operation causes the small piston 32 to come out of the conduit 21 and brings the reservoir of the additives into communication with the gap 15 defined between the fine filter cartridge 4 and the sleeve 10. This operation is carried out with the engine idling and therefore with the lubricating oil circulating pump in operation. Under these conditions, the pressure of the lubricant, even if it is small, opens the valve 25, so that the lubricant, which normally is confined above the wall 20, can pass through the hole 24 and invade the reservoir of the additives, mixing therewith, to then flow out through the conduit 21 and the elbow 22 up to the gap 15. Here the lubricant having a high concentration of fresh additives mixes with the lubricant subjected to fine filtering and leaves the filter through the intermediate hole 7 leading to the oil sump where the additives mix with a larger quantity of lubricant until they rapidly reach the optimum concentration. The operation of reintegration only takes a few seconds and after that the user screws up the knob 35 again. By the closure of the reservoir, the lubricant contained therein is excluded from the lubricating circuit the volume of which will, however, remain unchanged by the addition of the additives. It is, however, to be taken into consideration that the volume of the reservoir is negligible in comparison with the overall volume of the lubricating circuit. Fig. 2 shows in a part sectional view a modification of the embodiment. of Fig. 1. According to this modification, the wall 20 is secured to the bowl 1 by means of a deep-drawn double step 40 made therein. In this case it is no longer necessary to use any gasket on the edge of the wall which is bent upwardly in the manner of a rib 41 forced against the deep-drawn step. As the wall 20 can no longer undergo any axial movement, the presence of the stop cup 38 on the small piston 32 is no longer required. In fig. 2 there is also shown the situation of opening of the conduit 21, which is obtained by extracting the piston plug 32. This is associated with opening of the valve 25 so as to permit the passage of the lubricant through the hole 24. As mentioned above, the mixture of lubricant and additives flows out of the reservoir 8 through the conduit 21. In fig. 3 there is illustrated a second embodiment of the filter according to the invention, again in the case of a filter with double filtering. As far as filtering is concerned, this filter has a structure and operation identical to the embodiment described in Fig. 1; therefore, the various parts have been given numbers corresponding to those of Fig. 1 with the addition of 100. The filter of Fig. 3 likewise comprises substantially a bowl 101 closed upwardly by a cover 102 and containing a rough filter cartridge 103 and a fine filter cartridge 104, the two cartridges being superimposed. In the cover there are provided inlet holes 105 for the lubricant to be filtered, an outlet hole 106 for the lubricant filtered by the cartridge 103, and an intermediate hole 107 for the lubricant filtered by the cartridge 104. An axial sleeve 110 secured upwardly between the cover and an annular gasket 113 feeds the lubricant coming from the cartridge 103 to the hole 106 and separates it by means of an annular gasket 112 inserted between the sleeve and the two cartridges 103, 104 from the lubricant coming from the cartridge 104, which is fed to the intermediate hole 107 and further to the oil sump. According to the invention there is a second bowl 120 between the bowl 101 and the filter cartridges, with the walls of this second bowl extending parallel to those of the bowl 101 and connected and secured thereto adjacent the cover 102. Thus, the bowl 120 extends coaxially to the bowl 101, but is separated therefrom so that between the two a reservoir 108 is formed for stocking the reverse of additives. A lower spring 128 keeps the filter cartridges in position and a relief valve generally indicated by 130 ensures passage of the lubricant even in case of clogging of the filter cartridges. The valve indicated by 130 is substantially constituted by a rubber ring 140 which normally closes holes 129 provided in the bottom of the cartridge 103. The ring 140 is kept in position by a disk 141 biassed by a helical spring 142 reacting against an appropriate seat 143 provided on the base of the sleeve 110. An outflow conduit 121 brings the reservoir 108 into communication with the gap 115 defined between the sleeve 110 and the fine filter cartridge 104. A piston valve 132 closes the lower end of the conduit 121 and is received in a seat 134 and engages with its lower threaded portion 133 the corresponding threaded portion 134′ of the seat 134. An outer knob 135 formed integrally with the body of the piston permits the end of the conduit 121 to be opened by unscrewing, and vice versa. Two elastic sealing rings 111 and 111' are fitted on the conduit 121 and more precisely on an axial hole provided in the bottom of the inner bowl 120 and in the bottom of the lower cartridge 103, respectively. In the upper portion of the inner bowl 120, in particular in the section bent horizontally, a hole 124 is provided which is closed by a one-way check valve 125 having the purpose of permitting the lubricant to enter the reservoir 108 when the conduit 121 is opened by the on-off piston valve 132. As in the previous case, when the conduit 121 is opened, the additives contained in the reservoir 108 are admitted into the flow of the lubricant oil. Fig. 4 illustrates a different embodiment of the filter according to the invention, in the case of continuous total (full-flow) filtering. The structure of the filter is substantially analogous to that of the filter of Fig. 1 and comprises a bowl 50 with a cover 52 completely identical to the cover 2 of Fig. 1, so that we may refrain from describing it. Accommodated in the bowl is a single filter cartridge 53 through which the lubricant entering the filter is continuously filtered. Arranged below the cartridge 53 is a wall 55 which in the portion below defines a reservoir 58 for a reserve of additives, as in the case of the filter of Fig. 1. Arranged in the interior of the cartridge 53 is an axial sleeve 57 secured upwardly to the cover of the bowl and provided with a shoulder 58' adapted to retain an annular sealing gasket 56 against the upper base of the cartridge 53. The sleeve 57 is formed integrally with a conduit 59 located therein and provided with an elbow 60 opening adjacent the upper portion of the cartridge 53 above an annular gasket 62 which prevents the filtered lubricant from entering the annular chamber 64 communicating with the intermediate outlet hole 65 leading to the oil sump. Downwardly the conduit 59 sealingly passes through the wall 55 and is closed by an on-off piston valve 66 completely identical to that of Fig. 1, so that we may refrain from describing it or its actuation or operation. It will be understood that also with this type of filter mixing of the lubricant with the additives is obtained, the additives being caused to rise through the conduit 59 up to the chamber 64 and being expelled therefrom through the intermediate hole 65. Fig. 5 illustrates a further embodiment of the filter according to the invention, again relating to a filter with continuous total (full-flow) filtering. This embodiment is analogous to the one of the filter of Fig. 3 and substantially comprises an outer bowl 70 closed by a cover 72, as described previously, and a second bowl 74 located inwardly of and coaxially to the first one and defining a gap 78 serving as a reservoir for the additives. Accommodated within the inner bowl 74 is a single filter cartridge 73 kept in position by a helical spring 75 reacting against the bottom of the inner bowl 74. In the interior of the cartridge 74 - at a certain distance therefrom - there is arranged an axial sleeve 80 which upwardly is firmly secured to the cover of the bowl and is provided with a shoulder 81 adapted to retain an annular gasket 83 against the upper base of the bowl 74. A second annular gasket 84 is arranged between the sleeve 80 and the inner wall of the cartridge 73 in the vicinity of the cover so as to define an annular chamber 85 closed to the flow of the filtered lubricant which leaves the filter by passing through the interior of the sleeve 80 and through the central hole 86. As in the case of Fig. 3, an axial conduit 89 brings the chamber 85 into communication with the reservoir 78 of the additives. Thus, mixing of the additives is obtained when the piston valve 88 is opened, followed by opening of the valve 90 due to the pressure of the lubricant in the inner zone of the 74.

Claims: Filter for lubricants of internal combustion engines, particularly for motor vehicles, comprising a bowl (1; 101; 50; 70) containing at least one filter cartridge (4; 104; 53; 73), a cover (2; 102; 52; 72) with a plurality of eccentric inlet apertures (5; 105) for the lubricant to be filtered and two outlet apertures for the filtered lubricant, an axial one (6; 106) and another intermediate one (7; 107), a sleeve (10; 110; 57; 80) which extends axially from said cover in the direction towards the bottom of the bowl, sealing means (12, 13; 112, 113; 56, 62; 83, 84) between the outer surface of said sleeve and said filter cartridge for insulating the flow of filtered lubricant and feeding it to said outlet apertures, characterized in that incorporated in said bowl (1, 101; 50, 70) is a reservoir (8, 108; 58, 78) for lubricant additives, communicating with said filter cartridge (4; 104; 53, 73) through a feed hole (24; 124) normally closed by a check valve (25; 125), and through a discharge conduit (21; 121; 59; 89) normally closed by an on-off valve (32; 132; 66; 88) actuatable, if desired, to mix the additives contained in said reservoir with the filtered lubricant. Filter for lubricants of internal combustion engines according to claim 1, characterized in that said reservoir (8; 58) for lubricant additives is defined by the bottom of said bowl (1; 50) and by a circular wall (20; 55) arranged transversely within the bowl below said filter cartridge (3; 53), said circular wall (20; 55) being provided with a central hole for sealingly mounting it on said conduit (21; 59) for discharging the additives, and with an intermediate feed hole (24) normally closed by a check valve (25). Filter for lubricants of internal combustion engines according to claim 2, characterized in that said circular wall (20; 55) is provided with an annular gasket (23) fitted on its peripheral edge for sealing against the inner wall of said bowl (1; 50). Filter for lubricants of internal combustion engines according to claim 2, characterized in that said circular wall (20) is sealingly secured to the wall of said bowl adjacent a deep-drawn double step (40) made in the bowl. Filter for lubricants of internal combustion engines according to claim 1, characterized in that said reservoir (108; 78) for the additives is defined by the inner wall of said bowl (101; 70) and by the outer wall of a second bowl (120; 74) extending coaxially and inwardly of the first one to which it is connected and secured, said second bowl being provided with an axial hole on the bottom for accommodating an additive discharge conduit (121; 89) and with a lubricant feed hole (124) normally closed by a check valve (125; 90). Filter for lubricants of internal combustion engines according to claim 1, characterized in that said on-off valve of said discharge conduit (21; 121; 59; 89) is constituted by a small piston (32; 132; 66; 88) arranged axially in said reservoir for the additives and actuatable from outside the filter. Filter for lubricants of internal combustion engines according to claims 1 and 6, characterized in that the base (33'; 133) of said small piston is threaded and is inserted in a likewise threaded guide (34'; 134) accommodated on the bottom of said bowl, said small piston extending beyond the bowl (1; 101; 50; 70) and being connected to a knob (35; 135) for actuation of the valve. Filter for lubricants of internal combustion engines according to claims 1, 3 and 6, characterized in that a cup (38) for limiting the axial movement of said wall (20; 55) is mounted on said small piston. Filter for lubricants of internal combustion engines, particularly for motor vehicles, comprising a bowl (1; 101) containing a rough filter cartridge (3; 103) and a fine filter cartridge (4; 104) arranged one above the other, a cover (2; 102) with at least one eccentric inlet aperture (5; 105) for the lubricant to be filtered, an axial outlet aperture (6; 106) for the lubricant filtered by the rough filter cartridge, and an intermediate outlet aperture (7; 107) for the lubricant filtered by the fine filter cartridge, a sleeve (10; 110) extending axially from said cover in the direction towards the bottom of the bowl up to the height of said rough filter cartridge, sealing means (12, 13; 112, 113) between the outer surface of said sleeve and said two filter cartridges to separate the flow of filtered lubricant coming therefrom, characterized in that said bowl further comprises a reservoir (8; 108) for lubricant additives, provided with a feed hole (24; 124) closed by a check valve (25; 125), said reservoir being further connected to said fine filter cartridge (4; 104) by a discharge conduit (21; 121) normally closed by an on-off valve (32; 132) actuatable, if desired, to mix the additives contained in said reservoir with the lubricant flowing in the filter. Filter for lubricants of internal combustion engines according to claim 9, characterized in that said reservoir (8) for the additives is defined on the bottom of the bowl (1) by a transverse wall (20) provided with a feed hole (24) normally closed by a check valve, and with a central hole for accommodating said discharge conduit (21), said on-off valve being constituted by a small piston screwed with its base (33') into a bush (34) mounted on the bottom of the bowl, said small piston being controlled by an outer knob (35). Filter for lubricants of internal combustion engines according to claim 9, characterized in that said reservoir (108) for the additives is defined between said bowl (101) and a coaxial inner bowl (120) with walls extending substantially parallel to the walls of the bowl (101).

Inventors: VILLANI, FRANCO
Applicants: TECNOCAR S.P.A.
Application year: 1986
Main classification: B01D27
IPC codes: B01D27, F01M9, B01D37, F01M11