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Title:
OIL DEGRADATION SUPPRESSION DEVICE FOR INTERNAL COMBUSTION ENGINE, FILM FOR SUPPRESSING OIL DEGRADATION, AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2010/097663
Kind Code:
A1
Abstract:
An alkaline substance-containing porous film (2OA, 20B) is installed on an inner wall surface (6A, 7A) of a space (8, 9) which is within an internal combustion engine and in which at least one of oil, oil mist, and blowby gas exists. Since the film is porous, the alkaline substance and acidic substances can be caused to contact each other, and can be reacted. Thus, the contact area can be increased, so that the neutralization reaction can be enhanced. Besides, since the film is installed as a separate component part, the masking as required in the material-applying or spreading process is not necessary, and thus manufacturing cost can be reduced.

Inventors:
KOIKE, Ryuji (1 Toyota-cho, Toyota-shi, Aichi-ken, 471-8571, JP)
MURAKAMI, Motoichi (1 Toyota-cho, Toyota-shi, Aichi-ken, 471-8571, JP)
FUWA, Yoshio (1 Toyota-cho,Toyota-shi, Aichi, 471-8571, JP)
YANAGIHARA, Takeshi (1099-20, Aza Marune,Oaza Kurozasa, Miyoshi-ch, Nishikamo-gun Aichi, 470-0201, JP)
INOUE, Tomio (1099-20, Aza Marune,Oaza Kurozasa, Miyoshi-ch, Nishikamo-gun Aichi, 470-0201, JP)
MATSUKAWA, Seiichi (Shiraishi Kogyo Kaisha Ltd, 1-4, Kitahama3-chom,Chuo-ku,Osaka-shi, Osaka, 541-0041, JP)
HOSOI, Kazuyuki (Shiaraishi Kogyo Kaisha Ltd, 1-4, Kitahama 3-chome,Chuo-ku,Osaka-shi, Osaka, 541-0041, JP)
MORITANI, Hiroshi (41-1 Aza Yokomichi, Oaza Nagakute, Nagakute-cho, Aichi-gun, Aichi-ken, 480-1192, JP)
Application Number:
IB2010/000058
Publication Date:
September 02, 2010
Filing Date:
January 14, 2010
Export Citation:
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Assignee:
TOYOTA JIDOSHA KABUSHIKI KAISHA (1 Toyota-cho, Toyota-shi, Aichi-ken, 471-8571, JP)
ADMATECHS COMPANY LIMITED (1099-20 Aza-Marune, Ooaza-KurozasaMiyoshi-cho,Nishikamo-gun, Aichi, 470-0201, JP)
SHIRAISHI KOGYO KAISHA, LTD. (1-4 Kitahama 3-chome, Chuo-kuOsaka-shi, Osaka, 541-0041, JP)
KOIKE, Ryuji (1 Toyota-cho, Toyota-shi, Aichi-ken, 471-8571, JP)
MURAKAMI, Motoichi (1 Toyota-cho, Toyota-shi, Aichi-ken, 471-8571, JP)
FUWA, Yoshio (1 Toyota-cho,Toyota-shi, Aichi, 471-8571, JP)
YANAGIHARA, Takeshi (1099-20, Aza Marune,Oaza Kurozasa, Miyoshi-ch, Nishikamo-gun Aichi, 470-0201, JP)
INOUE, Tomio (1099-20, Aza Marune,Oaza Kurozasa, Miyoshi-ch, Nishikamo-gun Aichi, 470-0201, JP)
MATSUKAWA, Seiichi (Shiraishi Kogyo Kaisha Ltd, 1-4, Kitahama3-chom,Chuo-ku,Osaka-shi, Osaka, 541-0041, JP)
HOSOI, Kazuyuki (Shiaraishi Kogyo Kaisha Ltd, 1-4, Kitahama 3-chome,Chuo-ku,Osaka-shi, Osaka, 541-0041, JP)
MORITANI, Hiroshi (41-1 Aza Yokomichi, Oaza Nagakute, Nagakute-cho, Aichi-gun, Aichi-ken, 480-1192, JP)
International Classes:
F02B77/04; C10M107/00; C23C26/00; F01M13/04
Domestic Patent References:
1995-11-30
Foreign References:
EP2080877A12009-07-22
JP2004285828A2004-10-14
JP2008214540A2008-09-18
US20040159304A12004-08-19
US3336223A1967-08-15
JP2008121474A2008-05-29
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Claims:
CLAIMS:

1. An oil degradation suppression device for an internal combustion engine, characterized by comprising a porous film that contains an alkaline substance and that is provided on an inner wall surface of a space which is within the internal combustion engine and in which at least one of oil, oil mist, and blowby gas exists.

2. The oil degradation suppression device according to claim 1, wherein the film has flexibility.

3. The oil degradation suppression device according to claim 1 or 2, wherein the film further contains a resin.

4. The oil degradation suppression device according to claim 3, wherein the resin is composed at least of one of polyurethane, silicone, modified silicone, acrylic resin, fluorocarbon resin, polyvinyl chloride, epoxy resin, polyethylene, and polypropylene.

5. The oil degradation suppression device according to any one of claims 1 to 4, wherein a thickness of the film is 0.1 to 1 mm.

6. The oil degradation suppression device according to any one of claims 1 to 5, wherein the film contains an alkaline substance at a concentration that is less than or equal to 70 wt%.

7. The oil degradation suppression device according to any one of claims 1 to 6, wherein: the film is formed as a separate component from the internal combustion engine; and the film, after being formed, is disposed on the inner wall surface of the space of the internal combustion engine.

8. The oil degradation suppression device according to any one of claims 1 to 7, wherein the film has a projected portion that is projected toward an inner portion of the space.

9. The oil degradation suppression device according to claim 8, wherein the film has a corrugated shape.

10. The oil degradation suppression device according to claim 8, wherein the film has a plurality of protruded portions.

11. The oil degradation suppression device according to claim 10, wherein a sectional shape of each of the protruded portions is at least one of a semicircular shape, a triangular shape, and a rectangular shape.

12. The oil degradation suppression device according to any one of claims 1 to 11, wherein the film has a plurality of holes.

13. The oil degradation suppression device according to any one of claims 1 to 12, wherein a pore within the film is smaller in size than an oil molecule and is larger in size than a molecule of an acidic substance.

14. The oil degradation suppression device according to any one of claims 1 to 12, wherein a pore within the film is larger in size than an oil molecule.

15. The oil degradation suppression device according to any one of claims 1 to 12, wherein the inner wall surface is at least one of an inner wall surface of a head, cover, and an inner wall surface of an oil pan.

16. The oil degradation suppression device according to claim 15, wherein the film on the inner wall surface of the head cover and on the inner wall surface of the oil pan has internal pores that are different between the inner wall surface of the head cover and the inner wall surface of the oil pan.

17. The oil degradation suppression device according to claim 16, wherein: the film having an internal pore that is smaller in size than an oil molecule and is larger in size than a molecule of an acidic substance is disposed on the inner wall surface of the head cover; and the film having an internal pore that is larger in size than the oil molecule is disposed on the inner wall surface of the oil pan.

18. A film for suppressing degradation of an oil of an internal combustion engine, characterized by comprising an alkaline substance, wherein the film is porous.

19. The film according to claim 18, wherein the film has flexibility.

20. A method for manufacturing the film for suppressing degradation of the oil according to claim 18 or 19, characterized by comprising: producing a mixture by mixing a resin, a water-soluble organic solvent, and an alkaline substance; forming a coating film by applying the mixture to a mold; and removing the organic solvent from the coating film.

Description:
OIL DEGRADATION SUPPRESSION DEVICE FOR INTERNAL COMBUSTION

ENGINE, FILM FOR SUPPRESSING OIL DEGRADATION, AND

MANUFACTURING METHOD THEREFOR

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to an oil degradation suppression device for an internal combustion engine arid, more particularly, to a device that suppresses degradation of oil of an internal combustion engine through the use of a novel film.

2. Description of the Related Art

[0002] In conjunction with internal combustion engines for use in motor vehicles and the like, there is always a demand for suppression of degradation of oil as a lubricating oil, and elongation of the life of the oil, and reduction of the frequency of the oil replacement. Oil is gradually contaminated with sludge as it is used, and such oil contaminated by sludge gradually fails to sufficiently function as a lubricant due to increase in viscosity and consumption of additives. Therefore, there is a need to suppress the sludge contamination in oil as much as possible.

[0003] The sludge is produced by, as major components, olefin, aroma, etc. contained in fuel, NOx and SOx contained in blowby gas or burned gas, and water. These major components react due to heat or acid to produce the sludge via precursors, such as a sludge precursor, a sludge binder, etc. Visually, the sludge is a muddy or slushy material.

[0004] In particular, acidic substances produced by the reactions between water, that is formed by condensation or the like within the internal combustion engine, and NOx and SOx contained in blowby gas serve as catalysts in the production of sludge. Contamination of such acidic substances into oil facilitates the production of sludge, and accelerates the degradation of oil, and deteriorates the functions of the lubricating oil.

[0005] As a countermeasure against contamination of such acidic substances, Japanese Patent Application Publication No. 2008-121474 (JP-A-2008-121474) describes a construction in which a sludge suppression layer containing an alkaline substance is formed on a surface of a site that does not constantly receive oil in the form of a liquid, and that contacts oil mist in the form of a gas. According to this construction, the acidic substances can be neutralized by the alkaline substance, whereby the production of sludge on the surface of the site or the adhesion of sludge to the surface thereof can be suppressed.

[0006] However, in the technology described in JP-A-2008-121474, the acidic substances can only contact and react with the alkaline substance that is present on the exposed surface of the sludge suppression layer. Thus, the foregoing technology still has a problem in terms of increase in the contact area between the alkaline substance and the acidic substances or increase in the area of reaction therebetween.

[0007] Besides, in the technology described in JP-A-2008-121474, the sludge suppression layer is formed by applying to an object surface (e.g., an inner surface of a head cover) a solution in which an alkaline substance is dispersed. This method by application of such a solution requires a troublesome masking process, leading to an increased manufacturing cost. Furthermore, the foregoing problem becomes even more conspicuous in the case the area in which the solution can be applied to is insufficient due to the contact area being insufficient, because the object surface often has a complex shape.

SUMMARY OF THE INVENTION

[0008] The invention provides an oil degradation suppression device for an internal combustion engine, a film for suppressing oil degradation, and a method for manufacturing the film which can increase the contact area of an alkaline substance with acidic substances, and that can also minimize or reduce the manufacturing cost.

[0009] A first aspect of the invention relates to an oil degradation suppression device for an internal combustion engine. The oil degradation suppression device for an internal combustion engine has a porous film that contains an alkaline substance and that is provided on an inner wall surface of a space which is within the internal combustion engine and in which at least one of oil, oil mist, and blowby gas exists.

[0010] According to this aspect of the invention, since the film is porous, acidic substances and the alkaline substance contact each other and therefore can be reacted within the film as well as on exposed surfaces of the film. Therefore, the contact area of the alkaline substance with the acidic substances can be considerably increased, so that the neutralization reaction can be considerably enhanced. Besides, since the film is installed as a separate component instead of being directly applied to or spread on the object surface, the masking as provided for the applying or spreading process is not needed, and therefore the manufacturing cost can be reduced or minimized. Furthermore, since the film brings about high-efficient neutralization effect, the area of installation can be reduced. Thus, the film in accordance with this aspect of the invention is very advantageous in reducing or minimizing the manufacturing cost.

[0011] In the foregoing construction, the film may have flexibility.

[0012] Because of the foregoing construction, the film can follow a complicated shape of an installation object surface, and is unlikely to be restricted in terms of the location of installation, so that the degree of freedom in conjunction with the location of installation heightens.

[0013] In the foregoing construction, the film may further contain a resin.

[0014] Due to the foregoing construction, sufficient self-shape retainability of the film can be secured.

[0015] In the foregoing construction, the resin may be composed at least of one of polyurethane, silicone, modified silicone, acrylic resin, fluorocarbon resin, polyvinyl chloride, epoxy resin, polyethylene, and polypropylene.

[0016] In the foregoing construction, a thickness of the film may be 0.1 to 1 mm.

[0017] In the foregoing construction, the film may contain an alkaline substance at a concentration that is less than or equal to 70 wt%.

[0018] The higher the concentration of the alkaline substance in the film as a final product, the higher neutralization effect can be obtained. However, if the concentration of the alkaline substance is excessively high, it becomes difficult for the film to retain its own shape. According to the test performed by the present inventors, it has been turned out that shape retainability can be secured if the concentration of calcium carbonate is less than or equal to 70 wt%. Hence, the concentration of the alkaline substance in the film may be less than or equal to 70 wt%.

[0019] In the foregoing construction, the film may be formed as a separate component from the internal combustion engine. The film, after being formed, may be disposed on the inner wall surface of the space of the internal combustion engine.

[0020] In the foregoing construction, the film may have a projected portion that is projected toward an inner portion of the space.

[0021] If a projected portion is provided as in the foregoing construction, it becomes possible to increase the surface area per unit area of installation of the film, and therefore the contact area with acidic substances; therefore, the neutralization effect of the film can be increased.

[0022] In the foregoing construction, the film may have a serpentine shape.

[0023] In the construction, the film may have a plurality of protruded portions.

[0024] In the foregoing construction, a sectional shape of each of the protruded portions may be at least one of a semicircular shape, a triangular shape, and a rectangular shape.

[0025] In the foregoing construction, the film may have a plurality of holes.

[0026] Due to the foregoing construction, not only a surface of the film, but also inner peripheral surfaces of the holes contact acidic substances, and introduce the acidic substances into the film. Accordingly, the contact area with the acidic substances increases, thus making it possible to improve the neutralization effect.

[0027] In the foregoing construction, a pore within the film may be smaller in size than an oil molecule and is larger in size than a molecule of an acidic substance.

[0028] According to the foregoing construction, only the acidic substances can enter the pores within the film, and the oil cannot enter the pores. Hence, the alkaline substance within the film can be caused to selectively contact and react with only acidic substances, and the inhibition of the neutralization reaction by oil within the film can be prevented, so that efficient neutralization of acidic substances becomes possible.

[0029] In the foregoing construction, a pore within the film may be larger in size than an oil molecule.

[0030] According to the foregoing construction, the oil can enter pores within the film, and oil-contained oxides contained in the oil can also enter the pores. Hence, the alkaline substance within the film can be caused to contact and react with the oil-contained oxides, so that the neutralization of the oil-contained oxides becomes possible.

[0031] In the foregoing construction, the inner wall surface may be at least one of an inner wall surface of a head cover, and an inner wall surface of an oil pan.

[0032] In the space in the head cover, condensed water is likely to form, and acidic substances are likely to be produced. Hence, if the film is installed on the inner wall surface of the head cover, the acidic substances formed in the space in the head cover can be effectively neutralized. On the other hand, in the space in the oil pan, the oil is stored, and is often contaminated with acidic substances. Therefore, if the film is installed on the inner wall surface of the oil pan, the acidic substances in the oil can effectively neutralized.

[0033] In the foregoing construction, the film on the inner wall surface of the head cover and on the inner wall surface of the oil pan may have internal pores that are different between the inner wall surface of the head cover and the inner wall surface of the oil pan.

[0034] In the foregoing construction, the film having an internal pore that is smaller in size than an oil molecule and is larger in size than a molecule of an acidic substance may be disposed on the inner wall surface of the head cover. Besides, the film having an internal pore that is larger in size than the oil molecule may be disposed on the inner wall surface of the oil pan.

[0035] A second aspect of the invention relates to a film for suppressing degradation of an oil of an internal combustion engine. The film contains an alkaline substance. The film is porous.

[0036] In the foregoing construction, the film may have flexibility.

[0037] A third aspect of the invention relates to a method for manufacturing the film for suppressing degradation of the oil described above with the second aspect. The manufacturing method includes: producing a mixture by mixing a resin, a water-soluble organic solvent, and an alkaline substance; forming a coating film by applying the mixture to a mold; and removing the organic solvent from the coating film.

[0038] According to the foregoing aspects of the invention, it is possible to provide an oil degradation suppression device for an internal combustion engine, a film for suppressing oil degradation, and a method for manufacturing the film which can increase the contact area of an alkaline substance with acidic substances, and can also minimize the manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The foregoing and further objects, features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:

FIG. 1 is a schematic sectional view of an internal combustion engine in accordance with an embodiment of the invention;

FIG. 2 is a perspective view of a film in accordance with the invention;

FIG. 3 is an enlarged view of a surface of the film through a scanning electron microscope (SEM);

FIG. 4 is an enlarged sectional view of the film through the scanning electron microscope (SEM), at a higher magnification than in the view of FIG. 3;

FIG 5 is a sectional view showing an example of a film adopting method;

FIG. 6 is a sectional view showing an example of the film adopting method;

FIG. 7 is a sectional view showing still another example of the film adopting method; FIG. 8 is a perspective view showing a first modification of the film;

FIG. 9 is a sectional view showing a state of installation of the first modification of the film;

FIG 1OA shows a plan view of a mold for manufacturing a second modification of the film;

FIG. 1OB shows a front elevation of the mold for manufacturing the second modification of the film;

FIG HA is a plan view of a mold for manufacturing a third modification of the film;

FIG HB shows a front elevation of the mold for manufacturing the third modification of the film;

FIG. 12 shows a plan view of a mold for manufacturing a fourth modification of the film;

FIG 12B shows a plan view of the mold for manufacturing the fourth modification of the film;

FIG 13 is a sectional view showing a fifth modification of the film;

FIG. 14 is a plan view showing a sixth modification of the film;

FIG 15 is a sectional view showing a first example of the internal structure of the film;

FIG. 16 is a sectional view showing a second example of the internal structure of the film; and

FIG. 17 is a sectional view showing a modification regarding the location of installation of the film.

DETAILED DESCRIPTION OF EMBODIMENTS [0040] Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings.

[0041] FIG 1 schematically shows a sectional view of an internal combustion engine to which the invention is applied. As shown in FIG. 1, an engine 1 includes a cylinder block 2, a piston 3, a crankcase 4 provided under the cylinder block 2, a cylinder head 5 attached to an upper portion of the cylinder block 2, a head cover 6 that is attached to an upper portion of the cylinder head 5 and that covers the upper portion of the cylinder head 5 from above, and an oil pan 7 that is attached to a bottom portion of the crankcase 4 and that covers the bottom portion from below. In this embodiment, the cylinder block 2 and the crankcase 4 are integrally formed, but may also be formed as separate members. A cylinder 16 is formed in the cylinder block 2, and the piston 3 is disposed within the cylinder 16 so as to reciprocate.

[0042] A valve mechanism chamber 8 is provided above the cylinder head 5. Concretely, the valve mechanism chamber 8 is made up of a space that is defined and surrounded by the cylinder head 5 and the head cover 6. In the valve mechanism chamber 8, there are provided an intake valve Vi and an exhaust valve Ve that open and close an intake port Pi and an exhaust port Pe, respectively, valve springs (not shown) each of which urges a corresponding one of the intake valve Vi and the exhaust valve Ve in a closing direction, and an intake camshaft Ci and an exhaust camshaft Ce that drives the intake valve Vi and the exhaust valve Ve, respectively, in the opening direction. The valve mechanism chamber 8 is supplied with oil for lubrication of a valve mechanism system via an oil supply opening (not shown).

[0043] A crank chamber 9 is provided below the cylinder block 2. Concretely, the crank chamber 9 is made up of a space that is defined and surrounded by the cylinder block 2, the crankcase 4, and the oil pan 7. The crank chamber 9 is provided with a crankshaft Cr. Oil O is stored in a bottom portion of the crank chamber 9. The oil surface of oil O shown in FIG 1 is inclined, because the engine 1 is mounted in an inclined manner.

[0044] An intake passageway 10 is provided with a throttle valve 11 and an air filter 12. A surge tank 13 is provided at a downstream side of the throttle valve 11. The engine 1 is a multi-cylinder internal combustion engine in this embodiment, and intake air is distributed from the surge tank 13 to the intake ports Pi of the cylinders of the engine 1. An exhaust passageway (not shown) is connected to the exhaust ports Pe of the cylinders.

[0045] The engine according to this embodiment is a spark ignition type internal combustion engine for a vehicle (concretely, a gasoline (petrol) engine), and has injectors "In" that inject fuel into the intake ports, ignition plugs (not shown) attached to the cylinder head 5. The kind of the engine, the number of cylinders, the use of the engine, etc., are not particularly limited. The engine may also be a compression ignition-type internal combustion engine (concretely, a diesel engine).

[0046] The valve mechanism chamber 8 and the surge tank 13 are interconnected for communication by a blowby gas passageway 14. The blowby gas passageway 14 is a passageway for sending blowby gas, which has entered the crank chamber 9 and then ascended through an oil dropping passageway 18 to the valve mechanism chamber 8, to the intake passageway 10, particularly to the surge tank 13. An inlet opening of the blowby gas passageway 14 is provided with a PCV valve 15 whose opening degree is adjusted according to the intake negative pressure or the load. Incidentally, the PCV is an abbreviation of positive crankcase ventilation. The valve mechanism chamber 8, and the intake passageway 10 upstream of the throttle valve 11 are interconnected for communication by a fresh air passageway 17. In this embodiment, the fresh air passageway 17 is connected to a position on the intake passageway 10 which is immediately downstream of the air filter 12.

[0047] The oil dropping passageway 18 is formed by a hole that penetrates the cylinder block 2 and the cylinder head 5 in the vertical direction. In this embodiment, a plurality of oil dropping passageways 18 are provided as shown in FIG. 1. The oil dropping passageways 18 are passageways through which the oil residing in the cylinder head 5 after lubricating the valve mechanism system is dropped toward the crank chamber 9 and to the oil pan 7, and are also passageways through which the blowby gas having flowed into the crank chamber 9 is sent to the valve mechanism chamber 8 as described above.

[0048] In particular, the engine 1 in this embodiment is provided with a film for suppressing degradation of the oil. The film is provided on an inner wall surface of a space within the engine in which at least one of oil, oil mist and blowby gas exists. In this embodiment, a first film 2OA is disposed on an inner wall surface 6A of the head cover 6, and a second film 2OB is disposed on an inner wall surface 7A of the oil pan 7.

[0049] The inner wall surface 6A of the head cover 6 forms an inner wall surface of the valve mechanism chamber 8 that is in formation of a room, and the inner wall surface 7A of the oil pan 7 forms an inner wall surface of the crank chamber 9 in formation of a room. Oil is accumulated in a bottom portion of the valve mechanism chamber 8, and oil mist and blowby gas exist above the oil surface. Similarly, in the crank chamber 9, oil O is stored in a bottom portion of the crank chamber 9, and oil mist and blowby gas exist above the oil O.

[0050] The film will be described in detail herein. As shown in FIG. 2, the film 20 has a basic shape of a flat thin sheet or film, and its thickness is, for example, about 0.1 to 1 mm, although the thickness is adjustable. The film 20 is porous as shown in FIG. 3 and FIG. 4, and has flexibility or suppleness. The film 20 contains at least an alkaline substance. Examples of the alkaline substance contained in the film 20 include calcium carbonate, calcium hydroxide, calcium oxide, potassium hydroxide, barium hydroxide, sodium carbonate, and sodium hydrogen carbonate, and other substances can also be used. The film 20 also contains resin for the purpose of binding alkaline substances, increasing the strength of the film, etc. The resin may be either one of thermosetting resin and thermoplastic resin. Examples of the resin include polyurethane, silicone, modified silicone, acrylic resin, fluorocarbon resin, polyvinyl chloride, epoxy resin, polyethylene, and polypropylene, and other resins may also be used. The resin and the alkaline substance adhere to each other physically by intermolecular force, and are not chemically bound.

[0051] This film 20, having flexibility, can be bent relatively freely, and can be cut into any size and shape. Referring back to FIG. 1, a first film 2OA is disposed in a bent state conforming a curved shape of an inner wall surface 6A of the head cover 6, and a second film 2OB is disposed in a bent state following a curved shape of an inner wall surface 7A of the oil pan 7. Incidentally, connecting portions of the first film 2OA with the PCV valve 15 and the fresh air passageway 17 are each provided with a hole that permits passage of blowby gas or fresh air.

[0052] As for methods of attaching the film 20, for example, attachment via a fastening piece or the like, such as a bolt, rivet, etc., attachment via an adhesive, etc. are possible. In an example shown in FIG 5, the film 20 is superimposed on an installation object surface 31 of an installation object 30, such as the head cover 6 or the oil pan 7, and is fixed to the installation object 30, via a plurality of bolts 32 and nuts 33 (only one of each is shown). Due to this construction, the film 20 can be attached as easily as common component parts. In an example shown in FIG 6, when another component part 34 is attached to an installation object 30 by bolts 32 and nuts 33, the film 20 is sandwiched between the installation object 30 and the another component part 34, and is fastened together therewith. This eliminates the need to add a fastening piece or the like, or to make a structural change. In an example shown in FIG. 7, the film 20 is adhered by an adhesive 35 to an installation object surface 31 of an installation object 30. The adhesive 35 is preferably an adhesive that has characteristics, such as oil resistance, high-temperature resistance, vibration resistance, etc., and concretely, may be a silicone resin-based adhesive..

[0053] Next, operation and effects of the embodiment will be described.

[0054] Inside the engine, NOx and SOx contained in the blowby gas react with water that is generated by condensation or the like, or that is contained in the blowby gas, so as to generate acidic substances, such as nitric acid HNO 3 , sulfuric acid H 2 SO 4 , etc. Such acidic substances induce the formation of sludge, and acidify and therefore degrade the oil. However, according to the embodiment, such acidic substances can be neutralized by reacting them with an alkaline substance contained in the film 20, whereby the production of sludge and the degradation of the oil can be considerably suppressed.

[0055] In particular, since the film 20 is porous, and has therein many pores, and since the internal pores of the film 20 are interconnected, the reaction can be caused to advance in the direction of thickness of the film 20, so that the acidic substances and the alkaline substance can be brought into contact and therefore can be reacted together within the film 20 as well as on exposed surfaces of the film 20. Thus, the contact area and the reaction area per unit area of the film or per unit installation area can be increased, so that the neutralization reaction can be considerably enhanced. It is to be noted herein that the alkaline substance contained in the film is gradually consumed in the reaction with the acidic substances, and therefore disappears with elapse of time; however, since the alkaline substance is physically adhered to the resin as stated above, and is not chemically bound therewith, the resin remains unaffected during and after the consumption of the alkaline substance. Hence, even after the alkaline substance is consumed, sufficient rigidity of the film can be secured.

[0056] Besides, since the film 20 is installed on an object surface as a separate component instead of being directly applied to or spread on the object surface, the masking as provided for the application process is not needed, and therefore the manufacturing cost can be reduced. Besides, the film 20 has flexibility, and is therefore able to follow a complicated shape of an object surface, and is unlikely to be restricted in terms of the location to be located at, and brings about high-efficient neutralization effect as described above, so that the area of installation can be reduced as compared with the related art. Hence, the film 20 of the embodiment is highly advantageous in suppressing the manufacturing cost.

[0057] Referring to FIG. 1, as for the valve mechanism chamber 8, the head cover 6 is exposed to outside air, and has relatively low temperature, so that condensed water is likely to form on the head cover 6. This condensed water is likely to react with NOx and SOx in the blowby gas so as to form acidic substances. However, the acid substances can be neutralized by the first film 2OA. Oxidized oil may sometimes fly and adhere to the first film 2OA. In such a case, the acidic substances in the adhered oil can be neutralized by the first film 2OA. Furthermore, since the first film 2OA can also function as a heat insulator, the film also has an advantage of suppressing the generation of condensed water, and suppressing the production of acidic substances. As for the crank chamber 9, the acidic substances contained in the oil O stored in the bottom portion thereof can always be neutralized by the second film 2OB dipped in the oil O. [0058] A method for manufacturing the foregoing film will be described. Firstly, resin, such as polyurethane or the like, is diluted with a water-soluble organic solvent such as N,N-dimethylformamide, or the like. At this time, a surface-active agent may also be added in order to adjust the size of pores of the film. Next, an alkaline substance, such as calcium carbonate or the like, is mixed into the diluted resin solution, and the thus-produced mixture is stirred thoroughly.

[0059] Next, the thus-obtained mixture is applied to or spread on a surface of a mold so as to form a coating film. When a flat planar film is to be made, the mold may be a simple flat plate, for example, a flat glass plate. The thickness of the coating film is adjustable.

[0060] Next, the organic solvent is removed from the coating film. Concretely, for example, in the case where the alkaline substance is calcium carbonate, the coating film is dipped in water together with the mold (may also be dipped after being separated from the mold) to desorb the organic solvent from the coating film. At the time of desorption, the paths along which the organic solvent passes become a foam formation, and the formed portions become pores in the final product of the film. Incidentally, since the organic solvent is soluble in water, the organic solvent can easily be desorbed. Heating is not necessary. Then, the coating film is removed from the mold, and is rinsed with hot or cold water to completely remove the organic solvent from the mold-contact surface of the film as well. After that, the coating film is dried. In this manner, a film as a final product is completed.

[0061] As is apparent from the foregoing manufacturing method, a film having an arbitrary basic shape can be made, by changing the mold shape. Therefore, as for the first film 2OA shown in FIG. 1, the planar film 20 as shown in FIG 2 can be installed by bending the film so to conform to the shape of the head cover inner wall surface 6A, and may also be manufactured so as to have a basic shape that conforms to the shape of the head cover inner wall surface 6A, and therefore can be installed without being bent or deformed. It is also possible to make a film by using the head cover as a mold. Substantially the same can be said regarding the second film 2OB shown in FIG. 1 as well.

[0062] It is to be noted herein that the higher the concentration of the alkaline substance in the film as a final product, the higher neutralization effect can be obtained. However, when the concentration of the alkaline substance is excessively high, the film becomes so brittle as to be unable to retain its own shape, and sometimes collapses. According to a experiment performed by the inventors about the balance between the neutralization effect and the shape retainability, it has been turned out that in the case of a combination of calcium carbonate and polyurethane, shape retainability can be secured if the calcium carbonate concentration is less than or equal to 70 wt%. Therefore, the concentration of the alkaline substance in the film may be less than or equal to 70 wt%.

[0063] Next, modifications of the foregoing film will be described.

[0064] In a first modification shown in FIG. 8, a film 2OC has a corrugated shape. FIG 9 shows an example in which the film 20 C is installed as the first film 2OA on the head cover inner wall surface 6A. In this construction, the film 2OC consequently has a plurality of projected portions 21 that are projected toward an inner portion of the valve mechanism chamber 8. With the provision of the projected portions 21, the surface area of the film per unit installation area, and therefore the contact area of the film with the acidic substances can be increased, and therefore the neutralization effect of the film can be improved. Incidentally, the film 2OC is fixed to the head cover inner wall surface 6A, via fastening pieces or an adhesive or the like as mentioned above, at a plurality of predetermined positions at which the film 2OC contacts the head cover inner wall surface 6A. This corrugated film 2OC is applicable to the second film 20B as well.

[0065] FIG 1OA to FIG. 12B show molds 36 to 38 for manufacturing films 2OD to 2OF in accordance with second to fourth modifications. FIGS. 1OA, HA and 12A are plan views, and FIGS. 1OB, HB and 12B are front elevations.

[0066] With regard to the second modification shown in FIG. 1OA and FIG. 1OB, the mold 36 has a flat planar base plate 39, and a plurality of protruded portions 40 that are formed on an upper surface of the base plate 39. The protruded portions 40 are each formed in a hemispherical shape. In the example shown in FIGS. 1OA and 1OB, the protruded portions 40 are arranged at equal intervals in the front-rear direction and the right-left direction. When the film 2OD is made on the mold 36, a plurality of protruded portions 22 having a hemispherical shape or a semicircular shape in cross section which correspond to the protruded portions 40 of the mold 36 are formed in the film 2OD. That is, the film 2OD has, in its basic shape, a protrusions-and-depressions shape that follows the upper surface or the forming surface of the mold 36.

[0067] If the film 2OD made in this manner is installed on the head cover inner wall surface 6A as shown in FIG. 9, the protruded portions 22 form the projected portions 21 that are projected toward an inner space in the valve mechanism chamber 8. Due to this construction, the second modification can achieve substantially the same operation and effects as the first modification.

[0068] The third modification shown in FIG. HA and FIG. HB, and the fourth modification shown in FIG 12A and FIG. 12B are different from the second modification, only in the shape of the protruded portions of the mold and the film, and other constructions thereof. In the third modification shown in FIG HA and FIG. 11B, protruded portions 41 of the mold 37 and protruded portions 23 of the film 2OE are each formed in a conical or steeple shape or in a triangular shape in cross section. Therefore, a basic shape of the film 2OE is the shape of a pinholder, or the shape of a bed of nails. In the fourth modification shown in FIG. 12A and FIG. 12B, protruded portions 42 of the mold 38 and protruded portions 24 of the film 2OF are each formed in a rectangular shape in cross section. In these films 2OE and 2OF, too, the protruded portions 23 and 24 form the projected portions 21 when the film is installed. Thus, the third and fourth modifications deliver substantially the same operation and effects as the first modification.

[0069] FIG. 13 shows a fifth modification. In a film 2OG in accordance with the fifth modification, protruded portions are not formed by molding a film into a curved shape as in the second to fourth modifications, but protruded portions 25 are formed by locally increasing the thickness of the film. Concretely, after a flat planar film is made, a mixture of resin, an organic solvent, and an alkaline substance is mounded on an upper surface of the flat planar film. Then, the mounded mixture of resin and the alkaline substance are integrated with the flat planar film through the organic solvent removing process and the drying process that are described above. In this manner, a plurality of protruded portions 25 are provided on the upper surface of the film 2OG. In the example shown in FIG. 13, the protruded portions 25 are formed in a semicircular shape in cross section. This fifth modification can deliver substantially the same operation and effects as the first modification. Incidentally, the method for forming the protruded portions 25 is not limited to the foregoing methods. For example, protruded portions 25 may be made separately from a flat planar film, and may be adhered to the film by an adhesive.

[0070] Next, a sixth modification shown in FIG. 14 will be described. A film 2OH in accordance with the sixth modification has a flat planar shape, and is provided with a plurality of holes 26 that penetrate the film 2OH in its thickness direction. In the example shown in FIG 14, the holes 26 have a square shape, and are arranged at equal intervals in the front-rear direction and the right-left direction. However, the shape of the holes, the manner of arrangement thereof, etc. are arbitrary. Due to the provision of the holes 26, the film 2OH has a lattice-like planar basic shape.

[0071] When the film 2OH is installed on an object surface, not only on a surface of the film 2OH that faces an inner space of an installation object (e.g., the valve mechanism chamber 8), but also inner peripheral surfaces 27 of each hole 26 (surfaces extending in the thickness direction) contact acidic substances, and introduce the acidic substances into the film 2OH. Accordingly, the contact area with the acidic substances increases, thus making it possible to improve the neutralization effect.

[0072] With regard to the manufacturing method for the film 2OH, for example, the film 2OH can be manufactured by making holes on the flat planar film 20 as shown in FIG. 2. Alternatively, the film 2OH can also be manufactured by, through the use of the mold 38 shown in FIG 12, applying a mixture of resin, an organic solvent and an alkaline substance onto portions of a base plate 39 between the protruded portions 42. Of course, a film having circular holes can also be made if the mold 36 or 37 shown in FIGS. 1OA and 1OB or FIGS. HA and HB is used.

[0073] FIG 15 and FIG. 16 show examples regarding an internal structure of the film. In a first internal structure example shown in FIG. 15, a reference numeral 28 denotes pores within the film 20, and a reference numeral 40 denotes molecules of nitric acid HNO 3 or sulfuric acid H 2 SO 4 , and 41 denotes oil molecules. The molecular weight of nitric acid HNO 3 is 63 and the molecular weight of sulfuric acid H 2 SO 4 is 98, whereas the molecular weight of oil is far larger than the molecular weights of nitric acid HNO 3 and sulfuric acid H 2 SO 4 . Therefore, the oil molecules are remarkably larger in size than the molecules of nitric acid HNO 3 and sulfuric acid H 2 SO 4 .

[0074] In the first internal structure example, the pores 28 within the film have a size that is smaller than the size of the oil molecules, and that is larger than the size of the molecules of nitric acid HNO 3 and sulfuric acid H 2 SO 4 . Concretely, assuming that the average hole diameter of the pores 28 is Dl, the average hole diameter Dl is smaller than the diameter of the oil molecules, and is larger than the diameters of the molecules of the nitric acid HNO 3 and the sulfuric acid H 2 SO 4 . Therefore, passage portions that connect the pores 28 also have a clearance that is smaller than or equal to the average hole diameter Dl. The size of the pores 28 can be adjusted by adjusting various conditions in the manufacturing processes.

[0075] In this structure, only the molecules of nitric acid HNO 3 and sulfuric acid H 2 SO 4 can enter the pores 28 within the film, and the oil cannot enter the pores 28. Hence, the alkaline substance within the film can be caused to selectively contact and react with only nitric acid HNO 3 and sulfuric acid H 2 SO 4 , and the inhibition of the neutralization reaction by oil within the film can be prevented, so that efficient neutralization of acidic substances becomes possible.

[0076] In a second internal structure example shown in FIG 16, a reference numeral 42 denotes molecules of oil-contained oxides that are contained in oil. The molecules of oil-contained oxides 42 have approximately the same size as oil molecules 41. In the second internal structure example, pores 28 within the film has a larger size than the oil molecules 41. Concretely, the average hole diameter D2 is larger than the diameter of the oil molecules. Therefore, passage portions that interconnect the pores 28 also have a clearance that is smaller than or equal to the average hole diameter D2.

[0077] In this structure, the oil can enter the pores 28 within the film, and the oil-contained oxides can also enter the pores 28. Hence, the alkaline substance within the film can be caused to contact and react with the oil-contained oxides contained in the oil, so that the neutralization of the oil-contained oxides becomes possible.

[0078] The first internal structure example is suitable for the film that is to be installed at a location where acidic substances are likely to occur. In this embodiment, the first internal structure example may be applied to the first film 2OA that is installed inside the head cover 6. On the other hand, the second internal structure example is suitable for the film that is to be dipped in oil. In this embodiment, the second internal structure example may be applied to the second film 2OB that is installed inside the oil pan 7.

[0079] FIG. 17 shows a modification regarding the location of installation of the film. As shown in FIG. 17, a baffle plate 44 is attached to the head cover 6 by bolts 45. The head cover 6 and the baffle plate 44 define an oil separator chamber 43 that has a shape for separating oil from blowby gas B. The head cover 6 and the baffle plate 44 are provided with pluralities of obstruction plates 46 and 47 (only one of each is shown), respectively. These obstruction plates 46 and 47 form a serpentine passageway. When the blowby gas B flows through the serpentine passageway, oil is separated from the blowby gas B, and the oil is prevented from being returned to the intake passageway 10 and being burned and consumed. Incidentally, the baffle plate 44 is provided with an inlet opening for introducing the blowby gas B into the oil separator chamber 43 from the valve mechanism chamber 8.

[0080] A film 201 is superimposed on a surface of the baffle plate 44 which is located inside the oil separator chamber 43. As can be understood from FIG. 17, the film 201 is sandwiched between the baffle plate 44 and the head cover 6, and is fastened together therewith when the baffle plate 44 is attached to the head cover 6 by the bolts 45. Incidentally, the obstruction plates 47 of the baffle plate 44 stand upright through openings that are formed in the film 201.

[0081] Similar to the valve mechanism chamber 8, the oil separator chamber 43 is likely to have low temperature and therefore water condensation due to exposure of the head cover 6 to external air. In this location, therefore, acidic substances are likely to be formed. However, the acidic substances can be effectively neutralized by the film 201. Besides, in the oil separator chamber 43, basically oil is not caused to flow, so that once sludge is formed, the sludge cannot be expected to be washed away by oil. However, the provision of the film 201 considerably suppresses the production of sludge, and prevents adhesion and accumulation of sludge on the inner wall surfaces of the oil separator chamber 43. Incidentally, the first example of the internal structure shown in FIG. 15 may be adopted in the film 201. The first film 2OA may also be installed on the head cover inner wall surface 6A, as in the construction shown in FIG. 1.

[0082] While the embodiments of the invention have been described above, embodiments other than the above-disclosed embodiments or constructions can be adopted. For example, it suffices that the location of installation of the film be an inner wall surface of a space in which at least one of oil, oil mist and blowby gas exists. For example, the film can be installed in on an inner wall surface of an oil passageway, an inner wall surface of a blowby gas passageway, an inner wall surface of an oil dropping passageway, an inner wall surface of a cylinder (excluding the piston sliding portions), etc. As for the use of the film, a combination of any two or more of the foregoing films 20 and 2OA to 201 that have mutually different structures as described above may also be installed. As for the structure of the film, one sheet of film may also have different structures in different portions. The sectional shape of the protruded portions of the film may also be a shape other than a semicircle, a triangle and a rectangle. Likewise, the shape of the holes of the film may also be a shape other than a rectangle and a circle.

[0083] While the invention has been described with reference to example embodiments thereof, it is to be understood that the invention is not limited to the described embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the disclosed invention are shown in various example combinations and configurations, other combinations and configurations, including more, less or only a single element, are also within the scope of the appended claims.