Internal combustion engine

Abstract

The invention relates to an internal combustion engine (1) having a cylinder crankcase delimiting a crank chamber and a lubricant pan (2) accommodating a lubricant sump, which lubricant pan has a lubricant pan top part (3) arranged between the crank chamber and the lubricant sump, and a lubricant pan bottom part fastened to the lubricant pan top part (3), wherein a plurality of connecting pieces (5) extend from a base component (4) of the lubricant pan top part (3) in the direction of the lubricant sump, which connecting pieces intersect in part and thereby form chambers (6) which are closed around the edges in sectional view, and wherein lubricant passage openings (7) formed in the lubricant pan top part (3) open into at least some of the chambers (6), via which lubricant passage openings the crank chamber and the lubricant sump are fluidically connected. According to the invention, at least one ventilation opening (11) opens into at least one of the chambers (6), into which none of the lubricant passage openings (7) open, which at least one ventilation opening additionally fluidically connects the crank chamber and the lubricant sump and has, in comparison to the lubricant passage openings (7), a smaller flow cross-section.

Description

[0001] The invention relates to an internal combustion engine, with a cylinder crankcase delimiting a crank chamber and a lubricant pan accommodating a lubricant sump, which has a lubricant pan upper part arranged between the crank chamber and the lubricant sump and a lubricant pan lower part fastened to the lubricant pan upper part, wherein a plurality of webs extend from a basic component of the lubricant pan upper part in the direction of the lubricant sump, which webs partially intersect and thereby form chambers with closed edges between them in section, and wherein lubricant passage openings formed in the lubricant pan upper part open into at least some of the chambers, via which lubricant passage openings the crank chamber and the lubricant sump are in flow connection.

[0002] From the prior art, for example, the document EP 2 039 895 B1 is known. This describes a structural oil pan for an internal combustion engine, provided with an upper opening and comprising a plastic element having a plurality of side walls that circumferentially delimit an interior space, and at least one transverse part that extends within said interior space such that it connects at least two of the side walls to one another. Provision is made for the plastic element to be an upper element formed integrally with the transverse part, the upper element extending between an upper end defining said upper opening and a lower end defining a lower opening, and for the pan to have a lower element having a base and sealingly attached to the lower end of the upper element, said upper element having internal ribs arranged opposite one another with respect to the base.

[0003] It is an object of the invention to propose an internal combustion engine which has advantages over known internal combustion engines, in particular reducing losses of the internal combustion engine by a lower lubricant level in the crankcase.

[0004] This is achieved according to the invention with an internal combustion engine having the features of claim 1. It is provided that at least one vent opening opens into at least one of the chambers into which none of the lubricant passage openings opens, which additionally connects the crankcase and the lubricant sump and has a smaller flow cross-section than the lubricant passage openings.

[0005] The internal combustion engine is, for example, a component of a motor vehicle, but can also be separate from it. The internal combustion engine preferably serves to drive the motor vehicle, thus providing a drive torque directed toward driving the motor vehicle. The internal combustion engine has the cylinder crankcase, in which the crank chamber is formed.

[0006] A crankshaft of the internal combustion engine is mounted in the crankcase for rotation about a rotational axis. For its support, the crankshaft has bearing journals, with which it is rotatably mounted in bearings held or formed by the cylinder crankcase. The bearing journals are arranged coaxially with the rotational axis of the crankshaft. Furthermore, the crankshaft has crank pins, which are arranged eccentrically with respect to the bearing journals or the crankshaft.

[0007] The crankpins are connected to the bearing journals via webs. The crankpins connect the internal combustion engine's pistons to the crankshaft. For this purpose, a connecting rod, for example, is rotatably mounted on one side of the crankpin and on the other side of the piston. The pistons, in turn, are mounted in cylinders for linear displacement, with the cylinders being located in the cylinder crankcase.

[0008] The crankcase, in which the crankshaft is located, is defined in the direction away from the cylinders by the lubricant pan. This pan comprises at least the upper and lower sections of the lubricant pan. The lubricant pan accommodates the lubricant sump, which is located between the upper and lower sections of the lubricant pan. The upper section of the lubricant pan is located between the lower section of the lubricant pan and the cylinder crankcase. The upper section of the lubricant pan defines the lubricant sump toward the crankcase and the crankcase toward the lubricant sump.

[0009] For example, the upper part of the lubricant pan is directly attached to the cylinder crankcase, and the lower part of the lubricant pan is directly attached to the upper part of the lubricant pan. Accordingly, the lower part of the lubricant pan is only indirectly attached to the cylinder crankcase via the upper part of the lubricant pan. It can of course also be provided that both the lower part of the lubricant pan and the upper part of the lubricant pan are directly attached to the cylinder crankcase. The only important thing is that the upper part of the lubricant pan, the lower part of the lubricant pan, and the cylinder crankcase are secured to one another.

[0010] During operation of the internal combustion engine, lubricant is supplied to the crankcase, particularly for lubrication and / or cooling, for example, of the crankshaft, the pistons, the connecting rods, and / or the bearings supporting the crankshaft and / or the connecting rods. Due to the moving parts in the crankcase, air is entrained into the lubricant. When the internal combustion engine is properly arranged, the lubricant introduced into the crankcase is forced by gravity toward the lubricant sump, particularly into the lubricant sump.

[0011] The lubricant initially reaches the upper part of the lubricant sump, namely the side of the upper part facing the crankcase. The lubricant passage openings are formed in the upper part of the lubricant sump, through which the crankcase and the lubricant sump are in fluid communication.

[0012] The lubricant flows through the lubricant passages from the crankcase into the lubricant sump. The lubricant is calmed down in the lubricant sump. This separates the air present in the lubricant from the lubricant. The lubricant, now free of air, can then be removed from the lubricant sump and fed to the crankcase. For this purpose, for example, the lubricant is removed from the lubricant sump using a lubricant pump and pumped again towards the crankcase or into the crankcase. Additionally or alternatively, the lubricant is fed to a cylinder head and / or a camshaft adjuster. Preferably, the lubricant removed from the lubricant sump is fed to a lubricant filter before it is fed to the crankcase, the cylinder head and / or the camshaft adjuster.The lubricant filter serves to separate dirt particles contained in the lubricant.

[0013] In order to achieve the lightest and most weight-saving design possible for the internal combustion engine, at least the upper part of the lubricant sump is designed in a lattice-like manner. Accordingly, it has several webs extending from its base component. The base component defines the crankcase in the direction of the lubricant sump, and the webs extend from the base component toward the lubricant sump, i.e., in the direction away from the crankcase.

[0014] The webs partially intersect; in particular, at least several of the webs are intersected by other webs, forming a chamber structure with multiple chambers that are open toward the lubricant sump. Viewed in section, the webs thus enclose several chambers, which are delimited toward the crankcase by the base component of the upper part of the lubricant sump. In the intended installation position of the internal combustion engine, the base component thus forms a ceiling for the chambers.

[0015] For example, the first of the webs run in a first direction, and the second of the webs run in a second direction different from the first direction. The first webs run parallel to each other, for example, at least in some areas or continuously. The first direction is, for example, parallel to the rotational axis of the crankshaft. The second webs, on the other hand, run at an angle relative to the first webs, thus forming an angle with them that is greater than 0° and less than 180°.

[0016] In this case, some of the second webs may run parallel to each other. However, the second webs may also be angled to each other or even skewed. Therefore, it is not necessary for the second webs to form the same angle with the first webs. Rather, the angles may be different.

[0017] The webs each have a free end on their side facing away from the base component, which protrudes toward the lubricant sump. Preferably, at least one of the webs, several of the webs, or all of the webs extend at least almost to a contact surface of the upper part of the lubricant sump, against which the lower part of the lubricant sump is supported, for example, via a seal. For this purpose, the lower part of the lubricant sump preferably has a counter-contact surface, which bears directly or indirectly, for example, via the aforementioned seal, against the contact surface of the upper part of the lubricant sump.

[0018] The contact surface preferably lies continuously in an imaginary plane, which is in particular parallel to the rotational axis of the crankshaft. Relative to the total height of the lubricant pan upper part, which corresponds, for example, to the distance between the side of the base component facing the crankcase and the imaginary surface, the distance between the web, the plurality of webs, or all webs and the imaginary plane is preferably at most 25%, at most 20%, at most 15%, at most 10%, or at most 5%.

[0019] Particularly preferably, the web merges into the contact surface via a curve, thus achieving a particularly small distance between the web and the contact surface. This creates a particularly high level of rigidity for the upper part of the lubricant pan and, accordingly, for the entire internal combustion engine. This has advantages with regard to the acoustic behavior of the internal combustion engine because vibration excitation is reduced due to the high rigidity.

[0020] However, the described design of the upper section of the lubricant sump with the chambers formed by the webs has the disadvantage that some of the air separated from the lubricant collects and remains in the chambers. Accordingly, the capacity of the lubricant sump for the lubricant is reduced. This results in a comparatively high lubricant level in the crankcase. This can cause the crankshaft to periodically immerse itself in the lubricant in the crankcase during engine operation, resulting in engine losses. This immersion also introduces more air into the lubricant, further exacerbating the problem.

[0021] For this reason, it is provided to form at least one vent opening in the upper part of the lubricant pan. The vent opening opens into the crankcase on the one hand and into one of the chambers on the other. Particularly preferably, such a vent opening is provided and formed in each of the chambers into which none of the lubricant passage openings opens. In order to nevertheless maintain the high rigidity of the upper part of the lubricant pan, the vent openings are designed to be small compared to the lubricant passage openings. This means that they have a smaller flow cross-section, i.e., their flow cross-section has a smaller flow cross-sectional area, than the lubricant passage openings.

[0022] This ensures, on the one hand, that the corresponding chamber can be reliably vented, meaning that the chamber's volume is available to absorb lubricant. At the same time, however, it ensures that the structure of the internal combustion engine is not weakened, thus reliably preventing unwanted acoustic abnormalities from the internal combustion engine.

[0023] A further development of the invention provides that the lubricant passage openings are formed in walls of the lubricant pan upper part, which delimit recesses open in the direction of the crank chamber and spaced from one another, wherein the recesses are arranged in the axial direction with respect to a rotational axis of a crankshaft of the internal combustion engine in overlap with crank pins of the crankshaft.

[0024] The walls are understood to be areas of the upper part of the lubricant pan that are preferably spaced apart from one another. The walls define the recesses in which lubricant accumulates during engine operation and flows through the lubricant passages into the lubricant sump. In this respect, the recesses can also be referred to as lubricant collection recesses.

[0025] The recesses overlap with the crankpin of the crankshaft in the axial direction relative to the rotational axis of the crankshaft. This means that one of the recesses is arranged in overlap with each of the crankpins. Conversely, one of the crankpins of the crankshaft is preferably arranged in overlap with each of the recesses. As a result, lubricant thrown off the crankshaft reaches the recesses directly and can be drained from there into the lubricant sump. The upper part of the lubricant pan, and in particular the walls, therefore represent a "lubricant scraper" of the internal combustion engine.

[0026] For example, it can be provided that the crankpins of the crankshaft, the webs of the crankshaft, and / or the connecting rods engage in the recesses at least temporarily during operation of the internal combustion engine. This achieves a particularly effective removal of the lubricant from the crankcase toward the lubricant sump. The recesses are, for example, torus-shaped, thus preferably having the shape of a section of a torus. The torus is preferably understood to be a rotational torus, which in turn is a rotating body of a circle.

[0027] A further development of the invention provides that the lubricant passage openings are arranged in two rows parallel to one another and to the rotational axis of the crankshaft, with fastening recesses formed in the upper part of the lubricant pan between the two rows, which are enclosed by the webs. The parallel arrangement of the rows to one another and to the rotational axis of the crankshaft is understood to mean an at least approximately parallel arrangement or an exactly parallel arrangement. In the former case, the angle between the rows and / or one of the rows and the rotational axis is, for example, at most 10°, at most 5°, or at most 2.5°.

[0028] At least two of the lubricant passage openings are located in each of the rows. The fastening recesses, which completely extend through the base component of the lubricant pan upper section, are formed between the rows. Each of the fastening recesses is preferably enclosed by the webs; for example, one or more webs merge into an annular web that completely encompasses the respective fastening recess. Particularly preferably, several of the webs extend from each of the annular webs. For example, the annular webs are enclosed by two webs running parallel to one another, which rest against the annular webs or merge into the annular webs.

[0029] The mounting recesses accommodate fastening elements, such as screws or bolts, by means of which the upper part of the lubricant pan is attached, for example, to the cylinder crankcase and / or the lower part of the lubricant pan. The central arrangement of the mounting recesses relative to the lubricant passage openings enables a particularly rigid and low-vibration design of the upper part of the lubricant pan.

[0030] A further development of the invention provides that, in addition to the vent opening, there is at least one further vent opening, wherein a flow cross-section of the further vent opening is larger than a flow cross-section of the vent opening and smaller than the flow cross-section of the lubricant passage openings. The at least one further vent opening is provided in addition to the at least one vent opening. Like the vent opening, it passes through the base component of the lubricant pan upper part and fluidically connects the lubricant sump to the crankcase. Furthermore, it can be provided that it opens into one of the chambers.

[0031] The additional vent opening has a larger flow cross-section than the vent opening. For example, the flow cross-sectional area of ​​the additional vent opening is at least 5, at least 7.5, or at least 10 times larger than the flow cross-sectional area of ​​the vent opening. The additional vent opening enables particularly effective venting of the lubricant sump.

[0032] Preferably, of course, several additional vent openings are provided. However, in order not to adversely affect the rigidity of the upper part of the lubricant pan, the number of additional vent openings is fewer than the number of vent openings. For example, the upper part of the lubricant pan has a factor of at least 2, at least 3, at least 4, or at least 5 more vent openings than additional vent openings. This achieves effective venting while simultaneously maintaining high rigidity of the internal combustion engine.

[0033] A further development of the invention provides for the lubricant passage openings to be non-circular and the vent opening to be round. To ensure the most efficient removal of lubricant from the crankcase to the lubricant sump, the lubricant passage openings have a non-circular shape. For example, the lubricant passage openings are designed as elongated holes or stadium-shaped. Of course, they can also be oval, for example, elliptical.

[0034] In any case, they extend further in a first direction than in a second direction perpendicular to the first direction, and are delimited in each of the directions by a continuous edge formed by the base component of the lubricant pan upper part. For example, the lubricant passage openings extend through the respective recess in the axial direction relative to the rotational axis of the crankshaft by at least 70%, at least 80%, or at least 90%.

[0035] The vent opening, however, is round to minimize the impact on the rigidity of the upper part of the lubricant sump. This means that the edge bordering the vent opening, which is itself formed by the base component, is circular or ring-shaped. The described design thus enables both effective drainage of the lubricant from the crankcase and effective venting of the lubricant sump.

[0036] A further development of the invention provides that the vent opening is formed in a geodetically highest area of ​​a region of the base component that defines the respective chamber, in the installed position of the internal combustion engine. In this respect, the region of the base component forms the roof of the respective chamber in the intended installed position. The vent opening passes through this roof, namely at the geodetically highest point of the roof. This achieves particularly effective venting of the chamber.

[0037] A further development of the invention provides that the vent opening is formed in one of the walls. The walls are understood to be those areas of the lubricant pan upper section that define the recesses that open toward the crankcase and were described above. This applies in particular if none of the lubricant passage openings open into the chamber defined by the wall toward the crankcase. Such a chamber is located, for example, between the mounting recesses. Creating the vent opening in the wall defining the chamber ensures sufficient ventilation at this location.

[0038] A further development of the invention provides that the further vent opening has dimensions in a first direction which are at least 75% and / or at most 125% of dimensions of one of the lubricant passage openings in the same direction and / or that the further vent opening has dimensions in a second direction perpendicular to the first direction which are at most 25% of dimensions of the lubricant passage openings in this direction.

[0039] In any case, both the additional vent opening and the lubricant passage opening are bounded by a continuous edge in both the first and second directions. The two directions are perpendicular to each other and intersect the corresponding edge of the respective opening.

[0040] For example, it is now provided that the additional vent opening has similar dimensions to the lubricant passage opening in the first direction, but is significantly smaller than the lubricant passage opening in the second direction. Accordingly, the dimensions of the additional vent opening in the first direction are at least 75%, at least 80%, at least 85%, or at least 90% of the dimensions of the lubricant passage opening.

[0041] Additionally or alternatively, the dimensions of the additional vent opening are at most 125%, at most 120%, at most 115%, or at most 110% of the dimensions of the lubricant passage opening. Particularly preferably, the dimensions of the first vent opening in the first direction correspond to the dimensions of the lubricant passage opening, also in the first direction.

[0042] Additionally or alternatively, the dimensions of the additional vent opening in the first direction are at most 50%, at most 25%, at most 20%, at most 15%, or at most 10% of the dimensions of the lubricant passage opening, also in the second direction. Such a design of the additional vent opening enables particularly effective venting without unduly reducing the rigidity of the lubricant pan upper section. The additional vent opening is particularly preferably round.

[0043] A further development of the invention provides that the vent opening has dimensions in the first and second directions that are at most 25% of the dimensions of the additional vent opening in the respective direction. In other words, the vent opening is significantly smaller than the additional vent opening. Preferably, both the vent opening and the additional vent opening are round.

[0044] This means that the diameter of the vent opening is at most 25% of the diameter of the other vent opening. However, the dimensions or diameter are particularly preferably less than 25%, preferably at most 20%, at most 15%, or at most 10%. This ensures high rigidity of the upper part of the lubricant pan while simultaneously providing good ventilation.

[0045] A further development of the invention provides that the vent opening has a diameter of at least 1 mm and / or at most 6 mm. The lower limit of 1 mm is used to achieve sufficient venting of the respective chamber through the vent opening. The upper limit of 6 mm is used to avoid adverse effects on the rigidity of the upper part of the lubricant pan. For example, the diameter is therefore at least 1 mm and at most 6 mm, at most 5 mm, at most 4 mm, at most 3 mm or at most 2 mm. Alternatively, the diameter can be at least 2 mm and at most 6 mm, at most 5 mm, at most 4 mm or at most 3 mm. Further alternatively, the diameter is at least 3 mm and at most 6 mm, at most 5 mm or at most 4 mm and so on.

[0046] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawings, without limiting the invention. In the drawings: Figure 1 is a schematic representation of a part of an internal combustion engine, and Figure 2 is a schematic sectional representation of a region of the internal combustion engine.

[0047] The Figure 1 shows a schematic representation of a part of an internal combustion engine 1, namely a region of a lubricant pan 2. Specifically shown is a lubricant pan upper part 3 of the lubricant pan 2, which separates a lubricant sump, which is jointly delimited by a lubricant pan lower part and the lubricant pan upper part 3, from a crankcase accommodated in a cylinder crankcase of the internal combustion engine 1.

[0048] The lubricant pan upper part 3 has a base component 4, which delimits the crankcase in the direction of the lubricant pan 2 or in the direction of the lubricant sump. Several webs 5 extend from the base component 4, only a few of which are identified by way of example. The webs 5 are arranged relative to one another in such a way that they form chambers 6 between them that are closed at the edges in cross-section. These, too, are identified by way of example only.

[0049] Lubricant passage openings 7 open into some of the chambers 6. These openings are formed in walls 8 that form part of the lubricant pan upper part 3 or the base component 4. The walls 8 define recesses that open toward the crankcase. It can be seen that the lubricant passage openings 7 are arranged in several rows that run at least approximately or even exactly parallel to one another.

[0050] Between the two rows of lubricant passage openings 7, fastening recesses 9 are formed in the lubricant pan upper part 3, each enclosed by an annular web 10. The fastening recesses 9 are merely indicated by way of example. The webs 5 partially extend into the annular webs 10 or extend from them. In the exemplary embodiment shown here, two of the webs 5 run parallel to each other and accommodate the annular webs 10 between them.

[0051] To prevent air from accumulating in the chambers 6 formed by the webs 5, at least one vent opening 11 is provided in the lubricant pan upper part 3. In particular, there are a plurality of vent openings 11, at least 10, at least 15, or at least 20 in the exemplary embodiment shown here. In addition to the at least one vent opening 11, there is at least one further vent opening 12. Likewise, further fastening recesses 13 are provided in the lubricant pan upper part 3. These are merely indicated by way of example.

[0052] The vent opening 11 and the additional vent opening 12 serve to vent the lubricant sump or chambers 6 toward the crankcase. It can be seen that the vent opening 11 has a significantly smaller flow cross-sectional area than the additional vent opening 12 and each of the lubricant passage openings 7. This ensures, on the one hand, sufficient venting of the chambers 6, while, on the other hand, the rigidity of the lubricant sump upper part 3 and thus of the entire internal combustion engine 1 is not compromised.

[0053] The Figure 2shows a schematic sectional view of a region of the internal combustion engine 1 in the region of one of the vent openings 11. It can be seen that the webs 5 surround the chamber 6 in a dome-like manner and that the vent opening 11 is formed at a geodetically highest point of the chamber 6 in the base component 4 in the installed position of the internal combustion engine 1. This achieves extremely effective venting of the chamber 6. LIST OF REFERENCE SYMBOLS:

[0054] 1 Internal combustion engine 2 Lubricant pan 3 Lubricant pan upper part 4 Base component 5 Web 6 Chamber 7 Lubricant passage opening 8 Wall 9 Mounting recess 10 Ring web 11 Ventilation opening 12 Ventilation opening 13 Mounting recess

Claims

1. Internal combustion engine (1), having a cylinder crankcase delimiting a crank chamber and a lubricant pan (2) accommodating a lubricant sump, which comprises a lubricant pan upper part (3) arranged between the crank chamber and the lubricant sump and a lubricant pan lower part fastened on the lubricant pan upper part (3), wherein multiple ridges (5) originate from a base component (4) of the lubricant pan upper part (3) in the direction of the lubricant sump, which ridges partially intersect and thus form chambers (6) which are peripherally closed in section between them, and wherein lubricant passage openings (7) formed in the lubricant pan upper part (3) open into at least part of the chambers (6), via which openings the crank chamber and the lubricant sump are fluidically connected, characterized in that, in at least one of the chambers (6), into which none of the lubricant passage openings (7) opens, at least one ventilation opening (11) opens, which additionally fluidically connects the crank chamber and the lubricant sump and has a smaller through-flow cross section in comparison to the lubricant passage openings (7).

2. Internal combustion engine according to claim 1, characterized in that the lubricant passage openings (7) are formed in walls of the lubricant pan upper part (3), which delimit depressions that are open in the direction of the crank chamber and are spaced apart from one another, wherein the depressions are arranged overlapping with crank pins of the crankshaft in the axial direction with respect to an axis of rotation of a crankshaft of the internal combustion engine (1).

3. Internal combustion engine according to any one of the preceding claims, characterized in that the lubricant passage openings (7) are provided in two rows arranged in parallel to one another and to the axis of rotation of the crankshaft, wherein fastening recesses (9) are formed between the two rows in the lubricant pan upper part (3), which are enclosed by the ridges (5).

4. Internal combustion engine according to in any one of the preceding claims, characterized in that, in addition to the ventilation opening (11), at least one further ventilation opening (12) is provided, wherein a through-flow cross section of the further ventilation opening (12) is larger than a through-flow cross section of the ventilation opening (11) and smaller than through-flow cross sections of the lubricant passage openings (7).

5. Internal combustion engine according to any one of the preceding claims, characterized in that the lubricant passage openings (7) are non-round and the ventilation opening (11) is round.

6. Internal combustion engine according to any one of the preceding claims, characterized in that the ventilation opening (11) is formed in a region, which is geodetically highest in the installed location of the internal combustion engine (1) of a region of the base component (4) delimiting the respective chamber (6).

7. Internal combustion engine according to any one of the preceding claims, characterized in that the ventilation opening (11) is formed in one of the walls (8).

8. Internal combustion engine according to any one of the preceding claims, characterized in that the further ventilation opening (12) has dimensions in a first direction, which are at least 75% and / or at most 125% of dimensions of one of the lubricant passage openings (7) in the same direction, and / or in that the further ventilation opening (12) has dimensions in a second direction perpendicular to the first direction, which are at most 25% of dimensions of the lubricant passage openings (7) in this direction.

9. Internal combustion engine according to any one of the preceding claims, characterized in that the ventilation opening (11) has dimensions in the first direction and the second direction which are at most 25% of the dimensions of the further ventilation opening (12) in the respective direction.

10. Internal combustion engine according to any one of the preceding claims, characterized in that the ventilation opening (11) has a diameter of at least 1 mm and / or at most 6 mm.

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