Crankcase with inner and outer coolant jacket

Abstract

crankcase (1) of an internal combustion engine comprising an outer coolant jacket (3), a drain channel (6) which leads through an outer wall (5) from the outside of the crankcase (1) into the outer coolant jacket (3), and a closure element (7) which sits in the drain channel (6) with a closure section (8) and closes it, characterized by an inner coolant jacket (4), and a connecting channel (10) that connects the inner coolant jacket (4) to the outer coolant jacket (3), wherein the closure element (7) has an extension section (11) which is received in the connecting channel (10) and forms a slit-shaped passage (12) with it.

Description

[0001] The invention relates to a crankcase of an internal combustion engine, which comprises an outer coolant jacket, a drain channel which leads the crankcase from the outside into the outer coolant jacket through an outer wall, and a closure element which sits in the drain channel with a closure section and closes it.

[0002] Such a crankcase is known, for example, from EP 0 457 051 A1. EP 0 457 051 A1 shows a cylinder crankcase of a liquid-cooled reciprocating piston internal combustion engine with V-shaped cylinders surrounded by cooling channels. To achieve more even cooling and to establish a favorable coolant drain on the flywheel-side end face of the cylinder crankcase, a transverse channel is provided. This cross channel connects the cooling channels of the cylinder banks and has a downwardly extending channel section through which the coolant can be drained. The channel section is delimited by a lower wall in which a downwardly facing threaded bore is provided, into which a drain plug is screwed sealingly.

[0003] DE 102 41 478 A1 shows a coolant channel of a motor vehicle with a coolant pump and a drain plug arranged in the region of a coolant channel. The drain plug is arranged within a housing wall of the coolant pump. The drain plug has a coolant channel that can be connected to the coolant channel of a crankcase wall and communicates with the environment, so that coolant can be drained by loosening the drain plug without having to completely remove it.

[0004] DE 10 2012 209 617 A1 discloses a pressure relief device with a valve device in a mobile hydraulic drive with a high-pressure accumulator. During servicing, the pressure relief device serves to specifically reduce the hydraulic pressure in a high-pressure area using the valve device. The high-pressure area can be connected to a low-pressure area via a receiving chamber. A pressure relief screw is located in the receiving chamber, which closes a connection between the high-pressure area and the low-pressure area via a valve body. When the pressure relief screw is turned in an opening direction, the connection between the high-pressure area and the low-pressure area is throttled open by the valve body. For this purpose, the valve body is integrally connected to a throttle body. The throttle body is designed as a collar on the pressure relief screw and delimits an annular gap.

[0005] DE 10 2019 110 609 A1 describes an oil drain plug with a closure end for connection to a drain opening for lubricant and an inner end located opposite the closure end. The oil drain plug has a first drain channel and a second drain channel, wherein the first drain channel has a first drain opening in the closure end and a first inflow opening in the inner end, and the second drain channel has a second inflow opening and a second drain opening located between the closure end and the inner end. This makes it possible to adjust the fill level between two different areas of a transmission housing, for example, a pan and a sump.

[0006] DE 44 07 984 A1 discloses a cooling system for a liquid-cooled reciprocating piston internal combustion engine, whose cylinder block and cylinder head are traversed by coolant. The coolant is pumped and, after passing through the internal combustion engine, is fed to a radiator in a closed circuit. The cylinder block contains an upper channel system associated with the combustion chambers of the cylinders and a separate lower channel system adjacent to the crankshaft.

[0007] DE 10 2006 013 373 A1 shows a sealing plug used on a thermostat housing of an oil filter housing. The sealing plug has an elongated shaft, at each of whose axially opposite ends a sealing surface is provided. The first sealing surface is provided at the first shaft end adjacent to a sealing plug head, which is designed to releasably secure the sealing plug in a through-bore of a component for engagement with a tool. The second sealing surface is arranged in the region of the second shaft end, which has a diameter that is larger than the transverse extent of the connecting section connecting the two shaft ends. After the sealing plug is inserted into a through-bore, two openings in the through-bore are closed fluid-tight by the two sealing surfaces, and the sealing plug can be quickly and easily removed from the through-bore.

[0008] DE 90 17 255 U1 shows a drain plug for a water tank on a heat exchanger.

[0009] The object of the present invention is to provide a crankcase in which two separate, mutually separated coolant jackets can be emptied by simple measures.

[0010] The problem is solved by a crankcase of an internal combustion engine, comprising an outer coolant jacket, a drain channel that leads the crankcase from the outside into the outer coolant jacket through an outer wall, and a closure element that sits in the drain channel with a closure section and closes it. The crankcase further comprises an inner coolant jacket and a connecting channel that connects the inner coolant jacket to the outer coolant jacket, wherein the closure element has an extension section that is received in the connecting channel and forms a gap-shaped passage with it.

[0011] One closure element thus closes the outer coolant jacket on the one hand, and separates the outer coolant jacket from the inner coolant jacket except for the gap-shaped passage on the other. Thus, only a single element, namely the closure element, is required to close both coolant jackets, i.e. the outer coolant jacket and the inner coolant jacket. To empty both coolant jackets, only one closure element needs to be removed. The coolant in the outer coolant jacket can then drain outwards through the drain channel. The coolant in the inner coolant jacket first drains through the connecting channel into the outer coolant jacket and from there through the drain channel to the outside.

[0012] To avoid static overdetermination of the closure element relative to the discharge channel on the one hand and the connecting channel on the other, the extension section forms a gap-shaped passage with the connecting channel, so that manufacturing and assembly tolerances can be compensated by the gap-shaped passage. Direct contact between the connecting element and the crankcase in the axial direction is avoided, resulting in different gap dimensions of the gap-shaped passage depending on manufacturing and assembly tolerances. Radial contact of the closure element with the connecting channel cannot be ruled out.

[0013] The extension section of the closure element protrudes through the outer coolant jacket and dips into the connecting channel with one end section. This means that only a portion of the extension section is located in the connecting channel. Furthermore, the extension section can also dip into only an initial section of the connecting channel without completely penetrating it.

[0014] In one embodiment, the connecting channel can be arranged in an intermediate wall between the outer coolant jacket and the inner coolant jacket, wherein the intermediate wall is arranged on a side of the outer coolant jacket opposite the outer wall. In this case, the drain channel and the connecting channel can be arranged along a common longitudinal axis.

[0015] The extension section can form an annular gap with the connecting channel, which can be arranged coaxially to a longitudinal axis of the connecting channel. The extension section and the connecting channel can be cylindrical. In this case, an outer diameter of the extension section is smaller than an inner diameter of the connecting channel, at least in the area where it extends into the connecting channel. Thus, the gap-shaped passage is formed in the form of an annular gap. However, it is also conceivable for the cross sections of the extension section and the connecting channel to have a contour other than a circle.

[0016] The connecting channel can be divided into different sections. The connecting channel can have a receiving section in which the extension section of the closure element is received or inserted. In this case, the receiving section can transition towards the inner coolant jacket into a conduit section that has a smaller inner diameter than the receiving section.

[0017] An annular surface can be formed between the receiving section and the line section, wherein the extension section of the closure element forms an annular gap to the annular surface on its end face. The extension section can have an outer diameter that is larger than an inner diameter of the line section, at least in the region in which it dips into the receiving section. In this case, the annular gap to the annular surface can have essentially the same gap width as an annular gap between the extension section and the connecting channel. This creates a labyrinth in which coolant flowing between the inner coolant jacket and the outer coolant jacket forms turbulences that ensure an additional sealing function and a pressure drop.

[0018] According to one embodiment, the drain channel has an internal thread into which the closure portion of the closure element is screwed with a corresponding external thread. This enables easy attachment of the closure element to the crankcase.

[0019] The closure element may have a head portion that protrudes outwardly from the discharge channel, wherein the head portion has an outer diameter that is larger than an inner diameter of the discharge channel.

[0020] To achieve a reliable sealing effect, a sealing element can be arranged between the head section of the closure element and the outer wall of the crankcase.

[0021] To ensure easy assembly of the closure element, the extension section of the closure element can have a smaller outer diameter than the closure section of the closure element or than an inner diameter of the drain channel.

[0022] An exemplary embodiment is explained in more detail below with reference to the drawings. Fig. 1 shows a cross section of a crankcase according to the invention, Fig. 2 shows an enlarged view of the cross section of the crankcase according to Fig. 1 in the area of ​​the inner coolant jacket and the outer coolant jacket and Fig. 3 shows an enlarged view of the cross section of the crankcase according to Fig. 1 in the area of ​​the connecting channel.

[0023] The Fig. 1 to 3 show different views of a crankcase 1 according to the invention and are described together below.

[0024] Fig. 1 shows a cross-section through the crankcase 1 of an internal combustion engine with a cylinder bore 2 along a cylinder axis Z. Several cylinder bores 2 can be arranged one behind the other. The cylinder bore 2 serves to accommodate a piston (not shown here) for driving a crankshaft (also not shown) about a crankshaft axis K.

[0025] An outer coolant jacket 3 and an inner coolant jacket 4 are arranged in the crankcase 1 for cooling the crankcase 1. The inner coolant jacket 4 is arranged closer to the cylinder axis Z than the outer coolant jacket 3.

[0026] Arranged in an outer wall 5 of the crankcase 1 is a drain channel 6, which opens from the outside into the outer coolant jacket 3. A closure element 7 for sealing and closing the drain channel 6 is located in the drain channel 6. The closure element 7 has a closure portion 8 that is received in the drain channel 6. Coolant is received in the outer coolant jacket 3, which can be drained from the outer coolant jacket 3 by removing the closure element 7 from the drain channel 6.

[0027] The outer coolant jacket 3 and the inner coolant jacket 4 are separated from one another by an intermediate wall 9. A connecting channel 10 is arranged in the intermediate wall 9 and fluidically connects the inner coolant jacket 4 with the outer coolant jacket 3. So that the outer coolant jacket 3 and the inner coolant jacket 4 are separated from one another in the operating state, the closure element 7 has an extension section 11 which dips into the connecting channel 10 and is partially received therein and forms a gap-shaped passage 12 with the connecting channel 10. The gap-shaped passage 12 allows an exchange of the coolant arranged in the inner coolant jacket 4 with the coolant received in the outer coolant jacket 3.However, the gap-shaped passage 12 reduces this exchange of coolant to a minimum, which is negligible compared to the coolant flows within the inner coolant jacket 4 and the outer coolant jacket 3. As a result, the coolant jackets 3, 4 remain separate from each other. The passage 12 also prevents static overdetermination of the closure element 7 with respect to the discharge channel 6 on the one hand and the connecting channel 10 on the other. The gap-shaped passage 12 allows for compensation of manufacturing and assembly tolerances.

[0028] On a side of the inner coolant jacket 4 facing away from a flame deck 13 into which the cylinder bore 2 opens, the latter has a bore section 14 from which the connecting channel 10 extends.

[0029] The connecting channel 10 has a receiving section 15 facing the closure element 7, in which an end section of the extension section 11 of the closure element 7 is received or immersed.

[0030] The receiving section 15 of the connecting channel 10 merges in the direction of the inner coolant jacket 4 into a line section 16 which has a smaller inner diameter than the receiving section 15.

[0031] In the embodiment shown, an annular ring surface 17 is formed between the receiving section 15 and the line section 16, which is arranged in a plane transverse to a longitudinal axis L of the connecting channel 10.

[0032] The extension section 11 has an outer diameter that is larger than the inner diameter of the line section 16. Furthermore, the closure element 7 is not fully inserted into the receiving section 15, so that a first annular gap section 18 of the passage 12, which is of circular design, is formed between the extension section 11 of the closure element 7 and the annular surface 17. Adjoining this gap is a cylindrical second annular gap section 19 between the extension section 11 of the closure element 7 and an inner wall of the receiving section 15 of the connecting channel 10, which opens into the outer coolant jacket 3. This results in a type of labyrinth seal in which the coolant, which flows, for example, from the inner coolant jacket 4 to the outer coolant jacket 3, is deflected twice by 90°.This results in turbulence in the flow of the coolant, which ensures an additional sealing function in order to keep the volume flow exchanged between the inner coolant jacket 4 and the outer coolant jacket 3 as low as possible.

[0033] The closure element 7 has a head portion 20 that protrudes outward from the drain channel 6. The head portion 20 has an outer diameter that is larger than an inner diameter of the drain channel 6 and thus forms a collar protruding from the closure portion 8 of the closure element 7. A sealing element 21 is arranged between the head portion 20 of the closure element 7 and the outer wall 5 of the crankcase 1, thereby sealing the outer coolant jacket 3 from the outside. To remove the closure element 7 from the drain channel 6, it has a hexagon socket 22 as an engagement means for a tool. List of reference symbols 1 crankcase 2 cylinder bore 3 outer coolant jacket 4 inner coolant jacket 5 Exterior wall 6 Drain channel 7 Closure element 8 Closure section 9 Partition wall 10 connecting channel 11 Extension section 12 passage 13 Flame deck 14 Bore section 15 Recording section 16 line sections 17 ring area 18 first annular gap section 19 second annular gap section 20 head section 21 Sealing element 22 hexagon socket K Crankshaft axis L Longitudinal axis Z cylinder axis

Claims

[1] Crankcase (1) of an internal combustion engine comprising an outer coolant jacket (3), a drain channel (6) which leads the crankcase (1) from the outside into the outer coolant jacket (3) through an outer wall (5), and a closure element (7) which sits with a closure section (8) in the discharge channel (6) and closes it, characterized by an inner coolant jacket (4), and a connecting channel (10) connecting the inner coolant jacket (4) to the outer coolant jacket (3), wherein the closure element (7) has an extension section (11) which is received in the connecting channel (10) and forms a gap-shaped passage (12) therewith. [2] Crankcase (1) according to claim 1, characterized in that the connecting channel (10) is arranged in an intermediate wall (9) between the outer coolant jacket (3) and the inner coolant jacket (4), wherein the intermediate wall (9) is arranged on a side of the outer coolant jacket (3) opposite the outer wall (5). [3] Crankcase (1) according to claim 1 or 2, characterized in that the extension section (11) forms an annular gap with the connecting channel (10). [4] Crankcase (1) according to one of claims 1 to 3, characterized in that the connecting channel (10) has a receiving section (15) in which the extension section (11) is received. [5] Crankcase (1) according to claim 4, characterized in that the receiving section (15) merges in the direction of the inner coolant jacket (4) into a line section (16) which has a smaller inner diameter than the receiving section (15). [6] Crankcase (1) according to claim 5, characterized in that an annular surface (17) is formed between the receiving section (15) and the line section (16). [7] Crankcase (1) according to claim 5 or 6, characterized in that the extension section (11) has an outer diameter which is larger than an inner diameter of the line section (16). [8] Crankcase (1) according to one of claims 1 to 7, characterized in that the discharge channel (6) has an internal thread into which the closure section (8) of the closure element (7) is screwed with a corresponding external thread. [9] Crankcase (1) according to one of claims 1 to 8, characterized in that the closure element (7) has a head portion (20) which projects outwardly from the discharge channel (6), and in that the head portion (20) has an outer diameter which is larger than an inner diameter of the discharge channel (6). [10] Crankcase (1) according to claim 9, characterized in that a sealing element (21) is arranged between the head portion (20) of the closure element (7) and the outer wall (5) of the crankcase (1). [11] Crankcase (1) according to one of claims 1 to 10, characterized in that the extension section (11) of the closure element (7) has a smaller outer diameter than the closure section (8) of the closure element (7).

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