Internal combustion engine for a motor vehicle

Abstract

The invention relates to an internal combustion engine (10) for a motor vehicle, with at least one combustion chamber (12), and with at least one cylinder head (18) which has at least one combustion chamber roof (16) which partially delimits the combustion chamber (12) and is assigned two exhaust ports (20) of the cylinder head (18) and a spark plug (28) which is held on the cylinder head (18) and is arranged at least partially between the exhaust ports (20), wherein one cylindrical recess (32) is provided per exhaust port (20) in the respective exhaust port (20) on a respective side (S), facing the spark plug (28), of the respective exhaust port (20).

Description

[0001] Internal combustion engine for a motor vehicle

[0002] The invention relates to an internal combustion engine for a motor vehicle, in particular for a motor vehicle, according to the preamble of patent claim 1.

[0003] Such an internal combustion engine for a motor vehicle, in particular for a car, is known, for example, from DE 102021 000690 A1. The internal combustion engine has at least one combustion chamber and at least one cylinder head, which has at least one combustion chamber roof partially delimiting the combustion chamber. Associated with the combustion chamber roof and thus with the combustion chamber are, in particular, two exhaust ports of the cylinder head and, in particular, one spark plug mounted on the cylinder head, which is arranged at least partially between the exhaust ports.

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

[0005] This object is achieved by an internal combustion engine having the features of patent claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0006] In order to further develop an internal combustion engine of the type specified in the preamble of patent claim 1 such that particularly efficient operation of the internal combustion engine can be achieved, according to the invention, a cylindrical recess is provided in each exhaust port on a respective side of the respective exhaust port facing the spark plug. The invention is based in particular on the following findings and considerations: A respective air flow through the respective exhaust port, also referred to as the exhaust port flow, is crucial for the performance of an internal combustion engine, also referred to as an internal combustion engine or internal combustion engine. For this purpose, a respective design of the respective exhaust port, also designed and referred to as an exhaust port, is crucial.However, the exhaust port design is typically subject to the following restrictions: The spark plug is advantageously positioned between the exhaust ports and thus between the exhaust valves assigned to the exhaust ports, but this can lead to a significant reduction in the respective air-flow cross-section of the respective exhaust port. The spark plug is advantageously cooled by a water jacket between a spark plug well, in which the spark plug is arranged, and the respective exhaust port, which can lead to a further reduction in the flow cross-section. The exhaust ports are typically produced using a casting core, which, for example, forms the cylinder head as a cast component or has a cast body produced by casting that has or forms the exhaust ports. The casting core can advantageously be demolded towards the top.However, this results in an actually unfavourable flow guidance, which can result in separation in the respective outlet channel, which can lead to a further reduction of the effective flow cross-section.

[0007] Possible options to at least reduce or avoid the aforementioned disadvantages and problems could, for example, include a cast surface with a conical machining in a valve seat ring, which is cost-effective but leads to very poor flow characteristics. Another conceivable option would be the use of a 2D contour milling cutter. For manufacturing reasons, however, this can only be manufactured parallel to the cylinder axis. This only results in moderate advantages in flow guidance, mainly in the fact that the wall thicknesses can be reduced compared to a cast surface because there is no need to maintain casting tolerances. This results in slightly larger channel cross-sections, but there is limited scope for optimization of strong separation (flow angle). However, this does result in significant additional costs (long downtimes).Furthermore, 5-axis machining of the exhaust port in the area of ​​the valve seat ring would be conceivable, but this would be very costly and therefore only makes sense for motorsport applications. This would, however, enable a particularly advantageous flow contour to be realized with advantageous cross-sections and minimal separation, so that a maximum effective flow cross-sectional area or maximum effective flow cross-section can be achieved. The invention now provides a cylindrical recess for each exhaust port, and thus for each exhaust valve, on the side of the respective exhaust port facing the spark plug. This ensures an advantageously large flow cross-section of the respective exhaust port through which air can flow, in a particularly cost-effective manner.The respective cylindrical recess is a mechanical machining process that involves, for example, a 1D movement, i.e., a one-dimensional movement of a tool for producing the respective recess or of the cylinder head as a workpiece, to create the respective cylindrical recess. In other words, the respective cylindrical recess can be created using only a one-dimensional movement, so that the respective cylindrical recess can be produced particularly time-efficiently and cost-effectively. The respective cylindrical recess allows for an advantageously large flow cross-section of the respective outlet channel, and compared to conventional solutions, flow angles in critical areas can be significantly optimized.It was found that the invention allows 90 percent of the throughput of a 5-axis machining process to be realized, while at the same time allowing the respective cylindrical recess to be produced particularly cost-effectively compared to such 5-axis machining. This allows for particularly efficient operation of the internal combustion engine in a particularly cost-effective manner.

[0008] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0009] The drawing shows:

[0010] Fig. 1 shows a partial schematic plan view of an internal combustion engine onto a combustion chamber roof of the internal combustion engine;

[0011] Fig. 2 shows a partial schematic and sectional perspective view of the internal combustion engine; Fig. 3 shows a partial schematic and sectional side view of the internal combustion engine along a section line AA shown in Fig. 1; and

[0012] Fig. 4 shows a partial schematic and sectional rear view of the internal combustion engine along a section line BB shown in Fig. 1.

[0013] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0014] Fig. 1 shows a partial schematic plan view of an internal combustion engine 10 designed as a reciprocating piston engine, thus as a reciprocating piston machine, for a motor vehicle, in particular for a motor vehicle and very preferably for a passenger car. The internal combustion engine 10 has at least one combustion chamber 12, which is partially delimited by a cylinder 14 and partially by a combustion chamber roof 16 (Fig. 2) of the internal combustion engine 10. The cylinder 14 is formed by a first housing element of the internal combustion engine 10, wherein the first housing element is, for example, a cylinder housing, in particular a cylinder crankcase. The combustion chamber roof 16 is formed by a second housing element of the internal combustion engine 10 designed as a cylinder head 18, wherein the cylinder head 18 is formed separately from the first housing element and connected to the first housing element.The combustion chamber 12 is also partially delimited by a piston which is arranged in the cylinder 14 so as to be translationally movable.

[0015] The combustion chamber 12 is assigned, in this case precisely, two exhaust ports 20, which are formed by the cylinder head 18, i.e., delimited, and thus extend within the cylinder head 18. A respective exhaust valve 22 is assigned, in particular precisely, to each respective exhaust port 20. Furthermore, in the combustion chamber 12, in this case precisely, two intake ports 24 are assigned. The intake ports 24 are also formed by the cylinder head 18, i.e., delimited, so that the intake ports 24 extend within the cylinder head 18. A respective intake valve 26 is assigned, in particular precisely, to each respective intake port 24. Furthermore, in the combustion chamber 12, in particular precisely, a spark plug 28 is assigned, which is formed separately from the cylinder head 18 and held on the cylinder head 18. For example, the cylinder head 18 has a spark plug shaft in which the spark plug 28 is at least partially arranged. This can be seen from Fig.1 also shows a water jacket 30, which, for example, runs at least partially within the cylinder head 18 and is thus formed by the cylinder head 18. A liquid coolant, which at least contains water, can flow through the water jacket 30. The spark plug 28 can be cooled by means of the coolant flowing through the water jacket 28. It can be seen that the spark plug 28 is at least partially surrounded by the water jacket 30 on its outer circumference, with at least a respective partial region of the water jacket 30 being arranged between the spark plug 28 and the respective exhaust port 20 or the respective exhaust valve 22. It can be seen from Fig. 1 that the spark plug 28 is at least partially arranged between the exhaust ports 20, in particular between the exhaust valves 22.In particular, the respective exhaust port 20 has a respective inlet opening, through which the respective exhaust port 20 itself, i.e., considered on its own, opens into the combustion chamber 12. Thus, for example, exhaust gas from the combustion chamber 12 can flow through the respective inlet opening and thus into the respective exhaust port 20 via the respective inlet opening, so that the exhaust gas from the combustion chamber 12 can be discharged via the exhaust ports 20. The spark plug 28 is arranged at least partially between the inlet openings of the exhaust ports 20.

[0016] In order to be able to realize a particularly efficient operation of the internal combustion engine 10 in a particularly cost-effective manner, a respective cylindrical recess 32 is provided for each exhaust channel 20 and thus for each exhaust valve 22 in the respective exhaust channel 20 on a respective side S of the respective exhaust channel 20 facing the spark plug 28.

[0017] A respective conical machining 34 of the respective exhaust port 20 can be seen particularly well in Fig. 2. Also particularly well visible in Fig. 2 is the cylindrical recess 32, which is designed as a one-dimensional recess, thus as a 1D recess. This is to be understood in particular that the respective cylindrical recess 32 is produced by a only one-dimensional relative movement between the cylinder head 18 and a tool by means of which the respective recess 32 is produced. For example, the respective tool is a milling cutter or milling head, so that, for example, the respective recess 32 is a mechanical machining of the cylinder head 18, designed in particular as a milling. A first flow line is illustrated at 36 in Fig. 3.The streamline 36 illustrates a first flow of the exhaust gas flowing through the respective inlet opening and thus flowing into the respective outlet channel 20 via the respective inlet opening and flowing through the respective outlet channel 20, wherein the first flow of the exhaust gas illustrated by the streamline 36 occurs or would occur if the respective outlet channel 20 did not have the respective notch 32. Furthermore, in Fig. 3, a second streamline 38 illustrates a second flow of the exhaust gas flowing through the respective inlet opening and thus flowing into the respective outlet channel 20 via the respective inlet opening and flowing through the respective outlet channel 20, wherein the second flow occurs because the respective outlet channel 20 has the respective cylindrical notch 32.From the flow lines 36 and 38, it can be seen that the respective notch 32 results in a significant improvement in the exhaust gas flow, allowing for particularly efficient and fuel-efficient operation of the internal combustion engine 10. Furthermore, the respective notch 32 can be manufactured cost-effectively.

[0018] Furthermore, it can be seen from Fig. 3 that the respective recess 32 has a first central axis 40. Furthermore, the cylinder 14 has a second central axis, which is also referred to as the cylinder axis. For example, the cylinder 14 is at least substantially rotationally symmetrical with respect to its cylinder axis (second central axis). In Fig. 3, a denotes a first angle, with the first central axis 40 enclosing the first angle a with a straight line 42. The straight line 42 runs parallel to the cylinder axis and is spaced apart from the cylinder axis.The respective first central axis 40 runs in a respective first plane, which runs parallel to the second central axis (cylinder axis) and spaced from the second central axis, and which runs parallel to a second plane extending centrally between the outlet channels 20, in particular between the inlet openings, in which second plane the second central axis (cylinder axis) runs. Viewed in this previously defined first plane, the respective first central axis 40 encloses the first angle α with the respective straight line 42 running parallel to the second central axis and in the first plane, which angle α preferably lies in a range from 20 degrees to 60 degrees inclusive.

[0019] In Fig. 4, the aforementioned tool, by means of which the respective cylindrical recess 32 is produced, is illustrated at 44. Thus, the respective tool 44 illustrates the respective cylindrical recess 32 itself. In addition, Fig. 4 shows a second angle, designated ß, which is enclosed, for example, by the respective tool 44, in particular by its third central axis, and the second central axis in a third plane in which both central axes 40 run. Thus, for example, the second angle ß, viewed in the third plane, is enclosed by the respective first central axis 40 and the second central axis (cylinder axis), wherein the second angle ß preferably lies in a range from 1 degree up to and including 20 degrees. As a result, a respective upper end E of the respective recess 32, facing away from the combustion chamber 12, is inclined away from the spark plug 28.

[0020] In addition, the spark plug shaft designated 46 in Fig. 4 can be seen, in which the spark plug 28 is at least partially arranged.

[0021] The tool 44 has, for example, a first diameter, in particular a first inner diameter, wherein, for example, the first diameter lies in a range from 5 mm to 16 mm inclusive. For example, the first diameter corresponds to a respective second diameter, in particular to a respective first inner diameter, of the respective cylindrical recess 32. Thus, it is provided, for example, that the respective second diameter of the respective cylindrical recess 32 lies in a range from 5 mm to 16 mm inclusive.

[0022] List of reference symbols

[0023] 10 Internal combustion engine 12 Combustion chamber 14 Cylinder 16 Combustion chamber roof 18 Cylinder head

[0024] 20 Exhaust port 22 Exhaust valve 24 Intake port 26 Intake valve 28 Spark plug

[0025] 30 Water jacket 32 ​​Cylindrical recess 34 Taper machining 36 First streamline 38 Second streamline

[0026] 40 first central axis 42 straight 44 tool 46 spark plug shaft E end

[0027] S side a first angle ß second angle

Claims

Patent claims 1. Internal combustion engine (10) for a motor vehicle, with at least one combustion chamber (12), and with at least one cylinder head (18), which has at least one combustion chamber roof (16) partially delimiting the combustion chamber (12), to which two exhaust ports (20) of the cylinder head (18) and a spark plug (28) held on the cylinder head (18) are assigned, which spark plug is arranged at least partially between the exhaust ports (20), characterized in that for each exhaust port (20) a cylindrical recess (32) is provided in the respective exhaust port (20) on a respective side (S) of the respective exhaust port (20) facing the spark plug (28).

2. Internal combustion engine (10) according to claim 1, characterized in that the respective cylindrical recess (32) has a respective first central axis (40), wherein the combustion chamber (12) is partially delimited by a cylinder (14) of the internal combustion engine (10), the cylinder (14) of which has a second central axis.

3. Internal combustion engine (10) according to claim 2, characterized in that the respective first central axis (40) runs in a respective first plane running parallel to the second central axis and spaced from the second central axis and in the respective first plane, which runs parallel to a second plane extending centrally between the outlet channels (20) and in which the second central axis runs, forms a first angle with a straight line (42) running parallel to the second central axis and in the first plane (a) which is in a range of 20 degrees to 60 degrees inclusive.

4. Internal combustion engine (10) according to claim 2 or 3, characterized in that the respective first central axis (40), viewed in a third plane in which both first central axes (40) run, encloses a second angle (ß) with the second central axis, which lies in a range from 1 degree up to and including 20 degrees, whereby a respective end (E) of the respective recess (32) facing away from the combustion chamber (12) is inclined away from the spark plug (28).

5. Internal combustion engine (10) according to one of the preceding claims, characterized in that the respective recess (32) has a respective diameter which lies in a range from 5 millimeters to 16 millimeters inclusive.

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