Internal combustion engine for automobiles

Abstract

Achieve efficient operation. [Solution] The present invention relates to an internal combustion engine (10) for a motor vehicle, comprising at least one combustion chamber (12) and at least one cylinder head (18) having at least one combustion chamber roof (16) partially defining the combustion chamber (12), the combustion chamber roof (16) being assigned two exhaust ports (20) of the cylinder head (18) and one spark plug (28) held in the cylinder head (18), the spark plug (28) being at least partially arranged between the exhaust ports (20), and for each exhaust port (20), a cylindrical recess (32) being provided within each exhaust port (20) on each side (S) facing the spark plug (28) of each exhaust port (20).

Description

[Technical Field]

[0001] The invention relates to an internal combustion engine for motor vehicles, in particular motor vehicles, according to the preamble of claim 1. [Background technology]

[0002] Such an internal combustion engine for a motor vehicle, in particular a motor vehicle, is already known, for example from DE 10 200 04 133 A1. The internal combustion engine has at least one combustion chamber and at least one cylinder head with at least one combustion chamber roof that partially defines the combustion chamber. The combustion chamber roof, and thus the combustion chamber, is assigned, in particular, to two exhaust ports of the cylinder head and, in particular, to one spark plug that is held in the cylinder head and that is arranged at least partially between the exhaust ports. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Application Publication No. 10 2021 000 690 A1 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the invention is to develop an internal combustion engine of the type mentioned at the outset in such a way that a particularly efficient operation can be achieved. [Means for solving the problem]

[0005] This problem is solved by an internal combustion engine having the features of claim 1. Advantageous configurations, including preferred developments of the invention, are set forth in the further claims.

[0006] To improve an internal combustion engine of the type set forth in the preamble of claim 1 so as to achieve particularly efficient operation of the engine, the present invention provides a cylindrical recess in each exhaust port on the side of the exhaust port facing the spark plug. The invention is based in particular on the recognition and consideration that the airflow, also called exhaust port flow, through each exhaust port is crucial for the performance of an internal combustion engine, also called a combustion engine. For this purpose, the design of each exhaust port, also called an exhaust port, is crucial. However, exhaust port design typically has the following limitations: Spark plugs are preferably arranged between the exhaust ports, and thus between the exhaust valves assigned to them, which can lead to a significant reduction in the flow area (cross-sectional area) of each exhaust port through which air can pass. Advantageously, the spark plugs are cooled by a water jacket located between the spark plug hole in which the spark plug is arranged and the respective exhaust port, which can also lead to a further reduction in the flow area. Exhaust ports are typically produced by casting cores, which may form, for example, a cylinder head as a cast part or a casting produced by casting that includes or forms the exhaust ports. Advantageously, the casting cores can be demolded upward. However, this can actually result in adverse flow control, which can result in separation (flow separation) at the respective exhaust ports and further reduce the effective flow cross-section.

[0007] One possible option to at least mitigate or avoid the aforementioned drawbacks and problems is the use of a conical cast surface, for example, in the valve seat ring. However, this would be inexpensive but would result in very poor flow characteristics. Furthermore, 2D contour milling could be used. However, for manufacturing reasons, this can only be produced parallel to the cylinder axis. This offers only modest advantages compared to cast surfaces: reduced wall thickness, since casting tolerances do not need to be maintained. This would result in a slightly larger duct cross-sectional area, but would only allow for limited optimization of strong separation (flow angle). However, this would already result in significant additional costs (long downtime). Furthermore, 5-axis machining of the exhaust port in the valve seat ring area would be considered, but this would be very expensive and would only make sense in motorsport applications. However, this would allow for particularly advantageous flow contours with favorable cross-sections and minimized separation, thereby maximizing the effective flow area or effective flow cross-section.

[0008] In the present invention, for each exhaust port, and thus for each exhaust valve, a cylindrical recess is provided in the exhaust port on the side of the exhaust port facing the spark plug. This allows a particularly large flow cross-section through which air can pass at each exhaust port, particularly at low cost. Each cylindrical recess is machined, for example, by a 1D movement of a tool that manufactures the recess or the cylinder head as a part. In other words, since each cylindrical recess can be manufactured using only one-dimensional movements, each cylindrical recess can be manufactured particularly efficiently in terms of time and cost. Each cylindrical recess allows a particularly large flow cross-section of each exhaust port, and significantly optimizes the flow angle in the critical range compared to conventional solutions. It has been found that the present invention allows for 90 percent of the flow rate of a 5-axis machining process. However, compared to such 5-axis machining, each cylindrical recess can be manufactured particularly inexpensively. This allows for particularly efficient operation of the internal combustion engine, particularly at low cost.

[0009] Further advantages, features and details of the present invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned in the above description and in the following description of the figures and / or shown only in the figures can be used not only in the respective combinations presented, but also in other combinations or alone without departing from the scope of the present invention. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a combustion chamber roof of an internal combustion engine as viewed from above. [Figure 2] 1 is a schematic perspective view of a cross section of an internal combustion engine; [Figure 3] 2 is a schematic side view of a cross section of the internal combustion engine taken along section line AA shown in FIG. 1. [Figure 4] 2 is a schematic rear view of the cross section of the internal combustion engine taken along the cutting line BB shown in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] In the various figures, identical or functionally identical elements are designated by the same reference numerals.

[0012] FIG. 1 is a schematic cross-sectional top view of an internal combustion engine 10 configured as a reciprocating engine for a motor vehicle, particularly a motor vehicle, and very preferably a passenger car. The internal combustion engine 10 has at least one combustion chamber 12, which is defined in part by a cylinder 14 and in part by a combustion chamber roof 16 ( FIG. 2 ) of the internal combustion engine 10. The cylinder 14 is defined by a first housing element of the internal combustion engine 10, such as a cylinder housing, particularly a cylinder block. The combustion chamber roof 16 is defined by a second housing element of the internal combustion engine 10, which is configured as a cylinder head 18, which is formed separately from and connected to the first housing element. The combustion chamber 12 is also defined in part by a piston arranged in the cylinder 14 so as to be translationally movable.

[0013] Each combustion chamber 12 is assigned, in this case, exactly two exhaust ports 20, which are formed, i.e., defined, by the cylinder head 18 and therefore extend through it. Each exhaust port 20 is assigned, in particular, exactly one exhaust valve 22. Furthermore, each combustion chamber 12 is assigned, in this case, exactly two intake ports 24, which are likewise formed, i.e., defined, by the cylinder head 18 and therefore extend through it. Each intake port 24 is assigned, in particular, exactly one intake valve 26. Furthermore, each combustion chamber 12 is assigned, in particular, exactly one spark plug 28, which is formed separately from and held in the cylinder head 18. For example, the cylinder head 18 has a spark plug hole in which the spark plug 28 is at least partially arranged. Also shown in FIG. 1 is a water jacket 30, which, for example, passes at least partially through the cylinder head 18 and is therefore formed by the cylinder head 18. A liquid coolant, which at least contains water, can pass through the water jacket 30. The coolant flowing through the water jacket 28 can cool the spark plugs 28. The spark plugs 28 are at least partially surrounded on their outer periphery by the water jacket 30, and at least one respective subregion of the water jacket 30 is arranged between the spark plugs 28 and the respective exhaust ports 20 or the respective exhaust valves 22. It can be seen from FIG. 1 that the spark plugs 28 are arranged at least partially between the exhaust ports 20, in particular between the exhaust valves 22. In particular, each exhaust port 20 has a respective inlet opening through which the exhaust port 20, viewed by itself, flows into the combustion chamber 12. This allows, for example, exhaust gases from the combustion chamber 12 to flow through the respective inlet openings and thus into the respective exhaust ports 20 via the respective inlet openings, so that the exhaust gases from the combustion chamber 12 can be discharged through the exhaust ports 20.In this case, the spark plug 28 is at least partially positioned between the inlet openings of the exhaust ports 20 .

[0014] In order to be able to achieve a particularly efficient operation of the internal combustion engine 10 at particularly low cost, for each exhaust port 20, and thus for each exhaust valve 22, a respective cylindrical recess 32 is provided in the respective exhaust port 20 on the side S of the respective exhaust port 20 facing the spark plug 28.

[0015] The respective conical machining 34 of each exhaust port 20 is particularly visible in Figure 2. Furthermore, the cylindrical recesses 32, which are formed as one-dimensional recesses, and thus as 1D recesses, are clearly visible in Figure 2. This means that each cylindrical recess 32 is produced by only one-dimensional relative movement between the cylinder head 18 and a tool that produces the respective recess 32. For example, the respective tool is a milling cutter or milling head, and therefore, for example, each recess 32 is the result of machining, in particular milling, the cylinder head 18.

[0016] In FIG. 3 , first streamlines are indicated by the reference numeral 36. Streamlines 36 represent first streamlines of exhaust gases flowing through the respective inlet openings and thus into the respective exhaust ports 20 via the respective inlet openings, and flowing through the respective exhaust ports 20, where the first flow of exhaust gases represented by streamlines 36 would occur, or would be thought to occur, if the respective exhaust ports 20 did not have the respective recesses 32. Furthermore, in FIG. 3 , second streamlines 38 represent second streamlines of exhaust gases flowing through the respective inlet openings and thus into the respective exhaust ports 20 via the respective inlet openings, and flowing through the respective exhaust ports 20, where the second flow would be caused by the respective exhaust ports 20 having the respective cylindrical recesses 32. From streamlines 36 and 38, it can be seen that the respective recesses 32 clearly improve the flow of exhaust gases, thereby enabling particularly efficient and fuel-saving operation of the internal combustion engine 10. Furthermore, the respective recesses 32 can be manufactured at low cost.

[0017] FIG. 3 also shows that each recess 32 has a first central axis 40. Furthermore, the cylinder 14 has a second central axis, also referred to as the cylinder axis. For example, the cylinder 14 is formed at least approximately rotationally symmetrical with respect to its cylinder axis (second central axis). In FIG. 3, a first angle is indicated by the symbol α, and the first central axis 40 forms a first angle α with a line 42. The line 42 runs parallel to the cylinder axis and is spaced apart from the cylinder axis. Each first central axis 40 runs in a respective first plane that runs parallel to the second central axis (cylinder axis) and is spaced apart from the second central axis. This first plane runs parallel to a second plane through which the second central axis (cylinder axis) passes, which extends through the center between the exhaust ports 20, particularly between the inlet openings. When viewed from this previously defined first plane, each first central axis 40 forms a first angle α with a respective line 42 passing through the first plane parallel to the second central axis, this first angle α preferably being in the range of 20 to 60 degrees.

[0018] In FIG. 4, the aforementioned tool for manufacturing each cylindrical recess 32 is indicated by the reference numeral 44. Accordingly, each tool 44 represents each cylindrical recess 32 itself. Furthermore, FIG. 4 also shows a second angle, denoted by the reference numeral β, which is formed, for example, by each tool 44, particularly its third central axis, and a second central axis in a third plane through which the two central axes 40 pass. Thus, for example, the second angle β is formed, as viewed from the third plane, by each first central axis 40 and the second central axis (cylinder axis), where the second angle β is preferably in the range of 1 to 20 degrees. As a result, the upper end E of each recess 32, located on the opposite side of the combustion chamber 12, is inclined away from the spark plug 28.

[0019] Also shown in FIG. 4 is a spark plug hole, designated 46 in FIG. 4, in which the spark plug 28 is at least partially disposed.

[0020] The tool 44 has, for example, a first diameter, particularly a first inner diameter, for example, in the range of 5 mm to 16 mm. For example, the first diameter corresponds to a respective second diameter, particularly a respective first inner diameter, of each cylindrical recess 32. Thus, for example, each second diameter of each cylindrical recess 32 is in the range of 5 mm to 16 mm. [Explanation of symbols]

[0021] 10 Internal combustion engine 12 Combustion chamber 14 cylinders 16 Combustion chamber roof 18 Cylinder head 20 exhaust port 22 Exhaust valve 24 intake port 26 Intake valve 28 Spark plug 30 Water Jacket 32 Cylindrical recess 34 Cone processing 36 First Streamline 38 Second streamline 40 First central axis 42 straight line 44 Tools 46 Spark plug hole E end S side α First angle β Second angle

Claims

1. An internal combustion engine (10) for a motor vehicle, comprising at least one cylinder head (18) having at least one combustion chamber (12) and at least one combustion chamber roof (16) partially defining said combustion chamber (12), said combustion chamber roof (16) being assigned to two exhaust ports (20) of said cylinder head (18) and one spark plug (28) held in said cylinder head (18), said spark plug (28) being at least partially arranged between said exhaust ports (20), For each of the exhaust ports (20), a cylindrical recess (32) is provided on each side (S) of the exhaust port (20) facing the spark plug (28). An internal combustion engine (10).

2. Each of the recesses (32) has a first central axis (40); the combustion chamber (12) being partially defined by a cylinder (14) of the internal combustion engine (10); The cylinder (14) of the internal combustion engine (10) has a second central axis.

2. An internal combustion engine (10) according to claim 1, characterized in that:

3. Each of the first central axes (40) passes through a respective first plane parallel to the second central axis and away from the second central axis, and extends through the center between the exhaust ports (20), and in each of the first planes parallel to the second central axis and away from the second central axis, forms a first angle (α) with a straight line (42) passing through the first plane parallel to the second central axis, The first angle α is in the range of 20 degrees to 60 degrees.

3. An internal combustion engine (10) according to claim 2, characterized in that

4. Each of the first central axes (40) forms a second angle (β) with the second central axis when viewed from a third plane through which the two first central axes (40) pass; the second angle (β) is in the range of 1 to 20 degrees; Each end (E) of each recess (32) on the opposite side of the combustion chamber (12) is inclined away from the spark plug (28). An internal combustion engine (10) according to claim 2 or claim 3, characterized in that

5. Each of the recesses (32) has a diameter ranging from 5 mm to 16 mm. An internal combustion engine (10) according to any one of claims 1 to 4, characterized in that

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