Valve control arrangement for an internal combustion engine

Abstract

The invention relates to a valve control arrangement (2) for an internal combustion engine, comprising an inlet and an exhaust valve (4) with a valve stem (6) which is movably mounted in a cylinder head bore (8), wherein the valve stem (6) has a valve disc (14) at a first end which interacts with a valve seat (16) and a valve stem head assembly (20) at a second, opposite end which is operatively connected with a cam element (22) with at least one cam projection (26) of a camshaft (24), wherein the valve stem head assembly (20) is biased relative to the cam element (22) by means of a valve spring assembly (50), wherein the valve spring assembly is designed as a solenoid valve spring assembly (50), wherein at least a first solenoid element (36) is provided in the valve stem head assembly (20) and a second solenoid element (44) is provided in the cylinder head bore (8).which are each polarized in the axial direction of the valve stem (6), wherein the first and second magnetic element (36; 44) are aligned with a common pole (40; 46) to each other..

Description

[0001] The present invention relates to a valve control arrangement for an internal combustion engine, comprising an inlet or exhaust valve with a valve stem which is movably mounted in a cylinder head bore, wherein the valve stem has at a first end a valve disc which interacts with a valve seat and at a second, opposite end has a valve stem head arrangement which is in operative communication with a cam element with at least one cam lobe of a camshaft, wherein the valve stem head arrangement is preloaded relative to the cam element by means of a valve spring arrangement.

[0002] Valve actuation arrangements for internal combustion engines are well known in the prior art. Depending on the number of cylinders, a valve train consists of several of these valve actuation arrangements. These arrangements affect both intake and exhaust valves. A spring assembly serves to preload the valve stem assembly against the camshaft, thus ensuring that the valve head rests against the valve seat. Particularly high engine speeds, such as those frequently encountered in sports cars, can lead to so-called floating valves with mechanical spring arrangements, resulting in inaccurate opening and closing times of the intake and exhaust valves. In the worst case, such high engine speeds can lead to spring breakage. To prevent this, pneumatic spring arrangements have been developed. An example of this can be found in German patent DE 10 2022 108 081 B4.However, these pneumatic spring assemblies exhibit relatively high wear and require a compressed air supply, and are therefore complex and expensive to manufacture and assemble.

[0003] The object of the present invention is therefore to eliminate the aforementioned disadvantages in a simple and cost-effective manner.

[0004] This problem is solved by designing the valve spring assembly as a magnetic valve spring assembly, wherein at least in the valve stem head assembly a first magnetic element and in the cylinder head bore a second magnetic element are provided, each polarized in the axial direction of the valve stem, with the first and second magnetic elements aligned with the same pole relative to each other. In this way, it is possible to reliably preload a valve stem conventionally actuated by a camshaft against the camshaft even at high engine speeds.

[0005] In an advantageous embodiment, the first magnetic element is designed as a permanent magnet. This ensures particularly simple manufacturing and assembly of the valve control arrangement.

[0006] In a further advantageous embodiment, the second magnetic element can be designed as a permanent magnet or as an electromagnet. The electromagnet offers increased flexibility with regard to control.

[0007] In a particularly advantageous embodiment, a third magnetic element is arranged above the first magnetic element in the cylinder head bore, with the first and third magnetic elements oriented with opposite poles to each other. While the first and third magnetic elements repel each other, an attractive force exists between them. This allows for higher valve spring rates. The third magnetic element can be designed as a permanent magnet or as an electromagnet.

[0008] In an alternative embodiment, the cam element is configured as a fourth magnetic element above the first magnetic element, wherein the at least one cam projection and the first magnetic element are aligned with the same pole relative to each other. The function of the fourth magnetic element corresponds to the function of the third magnetic element in the previous embodiment. In this case, the cam element can be made of a magnetic material, or at least its outer circumference can be magnetized.

[0009] Especially in view of the high centrifugal forces that occur at high engine speeds, at least the first magnetic element is encapsulated by a metallic material and / or carbon.

[0010] The invention is explained in more detail with reference to a drawing. This drawing shows: Fig. 1 a schematically simplified sectional view of a first embodiment of a valve control arrangement according to the invention, Fig. 2 a schematically simplified sectional view of a second embodiment of the valve control arrangement according to the invention, Fig. 3 a schematically simplified sectional view of a third embodiment of the valve control arrangement according to the invention, which is an alternative to the second embodiment and has a closed inlet valve, and Fig. 4 a schematically simplified sectional view of the third embodiment of the valve control arrangement according to the invention with an open inlet valve.

[0011] Fig. Figure 1 shows a schematically simplified sectional view of a first embodiment of a valve control arrangement 2 according to the invention. Shown here is an inlet valve 4 whose valve stem 6 is movably mounted in a cylinder head bore 8 of a cylinder head 10 by means of a plain bearing 12 in a known manner. The valve stem 6 has a valve head 14 at a first end which interacts with a valve seat 16 such that an inlet bore 18 is opened or closed. At an opposite end of the valve stem 6, a valve stem head assembly 20 is provided, onto which a cam element 22, which is arranged on a camshaft 24, engages to open and close the inlet valve 4. For opening the inlet valve, the cam element 22 has a cam projection 26.In the present embodiment, the valve stem assembly 20 has a valve stem head 28 with recesses 30, 32 in which a housing 34 for a first magnetic element 36 is positively locked in place via a bearing element 38. In the present embodiment, the housing 34 is designed as a carbon fiber-reinforced metal housing. It should be clear that, due to the positive locking via the bearing element 38, the first magnetic element 36 follows the movement of the valve stem 6. The first magnetic element 36 is axially magnetized, with a south pole 40 pointing towards the valve head 14 of the inlet valve 4. Reference numeral 42 designates a north pole of the first magnetic element 36. Below the first magnetic element 36, i.e., between the first magnetic element 36 and the sliding bearing 12, a second magnetic element 44 is fixedly arranged in the cylinder head bore 8.The second magnetic element 44 is also axially polarized and has a south pole 46 and a north pole 48. According to the invention, the south pole 46 of the second magnetic element is positioned opposite the south pole 40 of the first magnetic element 36. In this way, the first and second magnetic elements form a magnetic valve spring assembly 50, which replaces a mechanical valve spring assembly. The two south poles 40, 46 of the first magnetic element 36 and the second magnetic element 44 exert a repulsive magnetic force on each other, so that the valve stem assembly 20 is constantly biased against the cam element 22. In the present embodiment, both the first magnetic element 36 and the second magnetic element 44 are designed as permanent magnets.

[0012] Fig. Figure 2 shows a schematically simplified sectional view of a second embodiment of the valve control arrangement 2 according to the invention. This embodiment additionally features a third magnetic element 52, which is fixedly arranged above the first magnetic element 36, i.e., between the first magnetic element 36 and the cam element 22. This third magnetic element 52 is also axially polarized and has a south pole 54 and a north pole 56. The south pole 54 is arranged opposite the north pole 42 of the first magnetic element and thus results in an attractive force between the first magnetic element 36 and the third magnetic element 52, which in particular ensures a higher valve spring rate. The third magnetic element 52 is also designed as a permanent magnet and is clipped into the cylinder head bore 8 by means of a clip arrangement 58.

[0013] The Fig. 3 and Fig. Figure 4 shows an alternative embodiment of the valve control arrangement 2 according to Fig. 2. Fig. Figure 3 shows the inlet valve 4 of the valve control arrangement 2 in a closed position and Fig. Figure 4 shows the valve control arrangement 2 with an inlet valve 4 in the open position. Instead of the third magnetic element 52, a fourth magnetic element 60 is provided here, which is formed by the cam element 22. The cam elevation 26 is configured as the north pole 62 and thus has the same polarity as the facing part of the first magnetic element 36. The remaining part of the cam element 22 is configured as the south pole 64 and thus has a different polarity than the facing part of the first magnetic element 36. This assists both the opening and closing movements of the inlet valve 4. Reference symbol list 2 Valve control arrangement 4 Inlet valve 6 Valve stem 8 cylinder head bore 10 cylinder head 12 plain bearings 14 valve plates 16 Valve seat 18 Inlet bore 20 Valve stem head arrangement 22 Camshaft 24 camshaft 26 Cam elevation 28 Valve stem head 30 Exclusion 32 Exclusion 34 cases 36 first magnetic organ 38 Storage organ 40 South Pole 42 North Pole 44 second magnetic organ 46 South Pole 48 North Pole 50 Valve spring assembly, solenoid valve spring assembly 52 third magnetic organ 54 South Pole 56 North Pole 58 clip arrangement 60 fourth magnetic organ 62 North Pole 64 South Pole

Claims

[1] Valve control arrangement (2) for an internal combustion engine, comprising an inlet and / or exhaust valve (4) with a valve stem (6) which is movably mounted in a cylinder head bore (8), wherein the valve stem (6) has at a first end a valve disc (14) which interacts with a valve seat (16) and at a second, opposite end a valve stem head arrangement (20) which is operatively connected with a cam element (22) with at least one cam projection (26) of a cam shaft (24), wherein the valve stem head arrangement (20) is biased relative to the cam element (22) by means of a valve spring arrangement (50), characterized by, that the valve spring arrangement is designed as a magnetic valve spring arrangement (50), wherein at least in the valve stem head arrangement (20) a first magnetic element (36) and in the cylinder head bore (8) a second magnetic element (44) are provided, each polarized in the axial direction of the valve stem (6), wherein the first and second magnetic elements (36; 44) are aligned with a common pole (40; 46) to each other. [2] Valve control arrangement (2) according to claim 1, characterized by , that the first magnetic organ (36) is designed as a permanent magnet. [3] Valve control arrangement (2) according to claim 1 or 2, characterized by , that the second magnetic organ (44) is designed as a permanent magnet or as an electromagnet. [4] Valve control arrangement (2) according to one of claims 1 to 3, characterized by, that a third magnetic organ (52) is arranged above the first magnetic organ (36) in the cylinder head bore (8), wherein the first and third magnetic organs (36; 52) are aligned with opposite poles (42; 54) to each other. [5] Valve control arrangement (2) according to claim 4, characterized by , that the third magnetic organ (52) is designed as a permanent magnet or as an electromagnet. [6] Valve control arrangement (2) according to one of claims 1 to 3, characterized by , that the cam organ (22) is formed as a fourth magnetic organ (60) above the first magnetic organ (36), wherein the at least one cam elevation (26) and the first magnetic organ (36) are aligned with a common pole (62; 42) to each other. [7] Valve control arrangement (2) according to claim 6, characterized by , that the cam organ (22) is made of a magnetic material or at least its outer circumference is magnetized. [8] Valve control arrangement (2) according to any one of the preceding claims, characterized by , that at least the first magnetic organ (36) is encapsulated by a metallic material and / or carbon.

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