PLASTIC HEAD COVER OF INTERNAL COMBUSTION ENGINE
A plastic head cover of an internal combustion engine having therein two parallel oil mist separator chambers comprises a plastic cover body that is adapted to be mounted on a cylinder head of the engine and includes lower portions of the separator chambers, and a plastic upper body that includes upper portions of the separator chambers and is mounted on and secured to the plastic cover body in such a manner that the upper portions possessed by the plastic upper body are mated with the lower portions possessed by the cover body, thereby forming an entire construction of the two oil mist separator chambers.
Latest MAHLE FILTER SYSTEMS JAPAN CORPORATION Patents:
1. Field of the Invention
The present invention relates to parts of an internal combustion engine, and more particularly to a plastic head cover of the internal combustion engine. More specifically, the present invention is concerned with a plastic head cover that is equipped with an oil mist separator.
2. Description of the Related Art
Some of head covers of internal combustion engine for motor vehicles are made of an engineering plastic and of a type that is equipped with an oil mist separator for separating and is removing an oil mist contained in a blowby gas that is produced by the engine. As is known, under operation of the engine, blowby gas is blown into a crankcase through a minute clearance between each piston and corresponding cylinder wall.
Some of plastic head covers of such type are disclosed in Japanese Laid-open Patent Applications (tokkai) 2003-293853 and 2011-122478. In the plastic head covers of the publications, a partition plate (or baffle plate) or the like is horizontally installed in a lower part of the head cover to constitute an oil mist separator chamber between an upper part of the head cover and the partition plate.
SUMMARY OF THE INVENTIONHowever, the plastic head covers disclosed by the publications have following drawbacks due to their inherent construction.
First, due to provision of the partition plate that is mounted to the lower part of the head cover, a blowby gas inlet opening has to be provided in a side wall of the head cover at a position above the partition plate because the oil mist separator chamber is located above the partition plate. The inlet opening has no undercutting for providing the plastic head cover with a sufficient mechanical strength. As is known, molding a plastic head cover that has the above-mentioned inlet opening without undercutting is difficult because of need of employment of a sliding jig in a molding process for forming the blowby gas inlet opening in a desired position of the side wall of a molded head cover. Of course, difficult molding process lowers a productivity.
Second, if the plastic head cover is of a type, like the head cover disclosed by the above-mentioned '853 publication, that has two parallelly extending oil mist separator chambers and a plurality of aligned openings between the two separator chambers for inserting therethrough ignition plugs, each portion extending between two neighboring openings has a wastefully thicker construction, which brings about increased weight of the products. Furthermore, in case of molding the plastic head cover of the above-mentioned type, it tends to occur that the produced plastic head cover shows some warping in directions perpendicular to an axis of the head cover. Of course, such warping lowers the precision of the products.
It is therefore an object of the present invention to provide a plastic head cover of an internal combustion engine, which is free of the above-mentioned drawbacks.
In accordance with a first aspect of the present invention, there is provided a plastic head cover (10) of an internal combustion engine, the plastic head cover having therein an oil mist separator unit (11, 12) for separating an oil mist from a gas led thereinto, the plastic head cover comprising a plastic cover body (21) adapted to be mounted on a cylinder head (1) of the engine, the cover body (21) including a lower portion of the oil mist separator unit (11, 12); and a plastic upper body (23) including an upper portion of the oil mist separator unit (11, 12), the plastic upper body being mounted on and secured to the plastic cover body (21) in such a manner that said upper portion possessed by the plastic upper body (23) is mated with said lower portion possessed by the cover body (21), thereby forming an entire construction of the oil mist separator unit (11, 12).
In accordance with a second aspect of the present invention, there is provided a plastic head cover (10) having therein first and second parallel oil mist separator chambers (11, 12) and adapted to be mounted on an internal combustion engine, the plastic head cover (10) comprising a plastic cover body (21) adapted to be mounted on a cylinder head (1) of the engine, the cover body (21) including a partition plate (22) that is formed with lower portions of the first and second oil mist separator chambers (11, 12); a plastic upper body (23) including upper portions of the first and second oil mist separator chambers (11, 12), the upper body (23) being mounted on and secured to the cover body (21) in such a manner that said upper portions possessed by the upper body (23) are mated with said lower portions possessed by the partition plate (22) of the cover body (21) thereby forming an entire construction of the first and second oil mist separator chambers (11, 12); a plurality of aligned plug bores (13) formed in an axially extending center zone of an integral unit between the first and second oil mist separator chambers (11, 12), the integral unit consisting of the cover body (21) and the upper body (23); a plurality of closed section structures (33) possessed by the axially extending center zone of the integral unit for increasing the rigidity of the axially extending center zone; and an L-shaped opening (16) that consists of a first portion (25) defined between a part of the cover body (21) and a part of the upper body (23) and a second portion (26) defined between another part of the cover body (21) and another part of the upper body (23).
Other objects and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which:
In the following, a plastic head cover of the present invention will be described in detail with reference to the accompanying drawings. The description will be made with respect to a case in which the head cover is applied to an inline three cylinder internal combustion engine.
For ease of understanding, in the following description, various directional terms, such as right, left, upper, lower, rightward and the like, are used. However, such terms are to be understood with respect to only a drawing or drawings on which a corresponding part or portion is shown.
Referring to
As will be understood from
As will become apparent as the description proceeds, the plastic head cover 10 of the invention comprises two main bodies, which are a cover body 21 that is mounted on the cylinder head 1 of the engine and an upper body 23 that is bonded to an upper portion of the cover body 21.
As will be understood from
As is seen from
As shown in
As is indicated by arrows in
As is seen from
As shown in
While, in a high load condition of the engine, the gas in the cylinder head 1 is led into the first oil mist separator chamber 11 from the air outlet opening 15 (see
As shown in
As is understood from
As is seen from
As is seen from
In order to clarify advantageous features possessed by the plastic head cover 10 of the present invention, a comparative example of plastic head cover 10H will be described with the aid of
It is to be noted that in these drawings, viz.,
As is seen from
As shown in
As is seen from
That is, due to an inherent construction, the partition plate 22H has to be placed inside the vertical passage part 25H of the blowby gas inlet opening 16H, and thus, the L-shaped blowby gas inlet opening 16H has to be formed by only the cover body 21H. That is, it is necessary to produce the L-shaped blowby gas inlet opening 16H by only the cover body 21H.
Accordingly, the cover body 21H has to have such a complex shape as not to permit a corresponding mold (not shown) to move in a releasing direction (viz., a vertical direction in
While, in the plastic head cover 10 of the present invention, the above-mentioned drawback is solved for the following reasons.
That is, as is seen from
Accordingly, molding the cover body 21 and upper body 23 can be easily carried out without the aid of the above-mentioned sliding jig 27 (see
As is shown in
Furthermore, the cylindrical wall of each plug bore 13H is formed with a sealing groove 29H at its lower end to hermetically receive therein an annular projection (not shown) formed on the cylinder head 1. Due to presence of the sealing groove 29H, the cylindrical wall of each plug bore 13H has a considerable thickness, which causes increase in weight of the product.
While, in the invention, as is seen from
As is seen from
As will be understood from
However, in the present invention, such undesired deformation is suppressed or at least minimized by a plurality of reinforcing ribs 32 possessed by the cover body 21, as will be understood from the following.
As is seen from
As shown in
That is, due to provision of such reinforcing ribs 32, the rigidity of the cover body 21 is increased, which prevents or at least minimizes the undesired deformation of the cover body 21 at the time of molding.
In case of the comparative example shown in
As is seen from
As is seen form
Due to provision of such closed section structures 33, the axially extending center zone of the plastic head cover 10 where various bores 13, 18 and 19 are provided can exhibit a sufficient rigidity. Actually, such closed section structures 33 compensate for lack of rigidity caused by the provision of the enlarged rounded parts 31 in the three plug bores 13.
As is seen from
However, provision of such bolt bore 19 has such a possibility that rain water or the like enters a groove 33a (see
The foregoing description is directed to a plastic head cover including a cover body 21 and an upper body 23 that are bonded to each other via a vibration welding method. However, if desired, coupling the cover body 21 and upper body 23 may be made through screws (or tapping screws) 40 as is seen in
The entire contents of Japanese Patent Application 2011-273978 filed Dec. 15, 2011 are incorporated herein by reference.
Although the invention has been described above with reference to an embodiment of the invention, the invention is not limited to such embodiment as described above. Various modifications and variations of such embodiment may be carried out by those skilled in the art, in light of the above description.
Claims
1. A plastic head cover of an internal combustion engine, the plastic head cover having therein an oil mist separator unit for separating an oil mist from a gas led thereinto, the plastic head cover comprising:
- a plastic cover body adapted to be mounted on a cylinder head of the engine, the cover body including a lower portion of the oil mist separator unit; and
- a plastic upper body including an upper portion of the oil mist separator unit, the plastic upper body being mounted on and secured to the plastic cover body in such a manner that said upper portion possessed by the plastic upper body is mated with said lower portion possessed by the cover body, thereby forming an entire construction of the oil mist separator unit.
2. A plastic head cover as claimed in claim 1, in which said lower portion of the oil mist separator unit is provided by a partition plate that is integral with the cover body.
3. A plastic head cover as claimed in claim 2, in which the oil mist separator chamber unit comprises first and second oil mist separator chambers that extend parallelly along a longitudinal axis of an integral unit that consists of the plastic cover body and the plastic upper body, and in which a plurality of aligned plug bores are formed in an axially extending center zone of the integral unit between the first and second oil mist separator chambers.
4. A plastic head cover as claimed in claim 3, in which each of the plug bores is formed at an axially middle portion thereof with an enlarged rounded part.
5. A plastic head cover as claimed in claim 4, in which each plug bore extends in a direction perpendicular to an imaginary contact surface at which an upper flat surface of the cover body and a lower flat surface of the upper body contact to each other.
6. A plastic head cover as claimed in claim 5, in which the cover body is integrally formed, at positions below the partition wall, with a plurality of reinforcing ribs, each reinforcing rib extending between laterally opposed side walls of the cover body.
7. A plastic head cover as claimed in claim 3, in which the axially extending center zone of the integral unit is constructed to have a plurality of closed section structures for increasing the rigidity of the axially extending center zone.
8. A plastic head cover as claimed in claim 7, in which each of the closed section structures comprises an enclosed rib that is possessed by the cover body and a counter-enclosed rib that is possessed by the upper body and bonded to the rib of the cover body.
9. A plastic head cover as claimed in claim 3, further comprising:
- a bolt bore formed in the axially extending center zone of the integral unit;
- a groove defined between the cover body and the upper body and exposed to the bolt bore; and
- a drain passage defined between the cover body and the upper body and extending from said groove to the outside of the integral unit.
10. A plastic head cover as claimed in claim 3, in which the integral unit is formed with an L-shaped opening that consists of a first portion defined between a part of the cover body and a part of the upper body and a second portion defined between another part of the cover body and another part of the upper body.
11. A plastic head cover having therein first and second parallel oil mist separator chambers and adapted to be mounted on an internal combustion engine, the plastic head cover comprising:
- a plastic cover body adapted to be mounted on a cylinder head of the engine, the cover body including a partition plate that is formed with lower portions of the first and second oil mist separator chambers;
- a plastic upper body including upper portions of the first and second oil mist separator chambers, the upper body being mounted on and secured to the cover body in such a manner that said upper portions possessed by the upper body are mated with said lower portions possessed by the partition plate of the cover body thereby forming an entire construction of the first and second oil mist separator chambers;
- a plurality of aligned plug bores formed in an axially extending center zone of an integral unit between the first and second oil mist separator chambers, the integral unit consisting of the cover body and the upper body;
- a plurality of closed section structures possessed by the axially extending center zone of the integral unit for increasing the rigidity of the axially extending center zone; and
- an L-shaped opening that consists of a first portion defined between a part of the cover body and a part of the upper body and a second portion defined between another part of the cover body and another part of the upper body.
Type: Application
Filed: Nov 12, 2012
Publication Date: Jun 20, 2013
Applicant: MAHLE FILTER SYSTEMS JAPAN CORPORATION (Tokyo)
Inventor: MAHLE FILTER SYSTEMS JAPAN CORPORATI (Tokyo)
Application Number: 13/674,341