Cylinder head arrangement for an internal combustion engine

Abstract

A cylinder head assembly (10) for an internal combustion engine of a motor vehicle is provided, comprising a timing chain (12) for a camshaft drive of the internal combustion engine, a chain case (14) for covering the timing chain (12), wherein the chain case (14) has a first cover wall (16) and a second cover wall (18) spaced apart from the first cover wall (16) at least over a transverse extent of the timing chain (12), an actuator (26) positioned adjacent to the first cover wall (16) for influencing a flow rate of a line (22) communicating with the internal combustion engine, and a support body (36) connected to the first cover wall (16) and the second cover wall (18) and extending past the timing chain (12) for providing a load transfer path between the actuator (26) and the second cover wall (18) in the event of a crash-related impact of the actuator (26) on a stop point. (32) of the first cover wall (16).By means of the support body (36) aligned with the position of the actuator (26) striking in the event of a crash, damage to the camshaft drive and the chain case (14) in the motor vehicle can be avoided at low cost and with little effort.

Description

[0001] The invention relates to a cylinder head assembly for an internal combustion engine of a motor vehicle, with the aid of which the operation of the internal combustion engine can be supported and which has a chain case for a timing chain of a camshaft drive.

[0002] From WO 2007 / 133131 A1, a transmission housing made of a light metal is known, the walls of which are supported against each other by rods so that the forces occurring when shifting gears do not deform the transmission housing.

[0003] From DE 10 2007 013 461 A1 a cylinder head of an internal combustion engine for a commercial vehicle is known in which a camshaft drive is covered with a cylinder head cover which can strike a support dome under a tread load.

[0004] There is a constant need to prevent damage to a motor vehicle in the event of a crash.

[0005] The object of the invention is to show measures that make it possible to avoid damage to a motor vehicle in the event of a crash.

[0006] The object is achieved according to the invention by a cylinder head arrangement having the features of claim 1 and an internal combustion engine having the features of claim 10. Preferred embodiments of the invention are specified in the subclaims and the following description, which may each individually or in combination represent an aspect of the invention, the scope of protection being determined by the claims.

[0007] One aspect of the invention relates to a cylinder head arrangement for an internal combustion engine of a motor vehicle, comprising a timing chain for a camshaft drive of the internal combustion engine, a chain case for covering the timing chain, wherein the chain case has a first cover wall and a second cover wall spaced from the first cover wall at least over a transverse extent of the timing chain, an actuator positioned adjacent to the first cover wall for influencing a flow rate of a line communicating with the internal combustion engine, and a support body connected to the first cover wall and the second cover wall and running past the timing chain for providing a load transfer path between the actuator and the second cover wall in the event of a crash-related impact of the actuator on a stop point of the first cover wall.

[0008] It was recognized that the timing chain case for the camshaft drive of the internal combustion engine does not have to absorb significant forces, as the case only serves as a contact guard and must retain the timing chain's lubricating oil. This allows the case to be manufactured simply and cost-effectively using a lightweight construction and a particularly thin material.However, in the event of a motor vehicle crash, the comparatively low load-bearing capacity and stability of the chain case could result in the chain case being compressed and plastically deformed between two rigid components, in particular the cylinder head of the internal combustion engine and the actuator, as a result of the impact forces occurring and the elastic and / or plastic deformations taking place within the motor vehicle, whereby the chain case, the timing chain and / or other components of the camshaft drive could be severely damaged and would have to be replaced.However, the support body within the chain case can prevent the actuator from indenting the first cover wall in the event of a crash. The support body absorbs the impact forces introduced by the actuator at the point of impact with the first cover wall and transfers them via the load transfer path provided by the support body past the timing chain to the second cover wall, where, in particular, the impact forces transferred via the support body can be supported on the cylinder head. By aligning the support body with the position of the actuator impacting in a crash, damage to the camshaft drive and the chain case in the motor vehicle can be avoided with little effort and at low cost.

[0009] The timing chain can be part of a chain drive of the camshaft drive in order to drive a camshaft. The camshaft can have cams with the help of which valves of combustion cylinders in the cylinder head of the combustion engine can be controlled. The timing chain can be positioned in front of one side of the cylinder head, in particular in the direction of travel of the motor vehicle (“X direction”). Preferably, the timing chain is actively driven via at least one gearwheel and / or passively guided via at least one gearwheel. The teeth of the respective gearwheel can engage with links of the timing chain. In particular, it is possible to specify the course of the timing chain by providing and positioning the gearwheels, so that the specified course of the timing chain can ensure that sufficient free space can be maintained for the support body in the area of ​​the stop point of the first cover wall.Impact of the support body on the timing chain can be avoided both during normal operation and in the event of a crash.

[0010] The chain case can cover the timing chain as contact protection and retain lubricating oil or grease falling from the timing chain. The chain case can in particular be based on a lightweight construction so that it is possible to minimize the material used in the chain case, which does not have to absorb any significant forces. Preferably, the chain case has a shell that surrounds the timing chain in a U-shape, which forms the first cover wall in whole or in part and can be fastened to the cylinder head so that the cylinder head itself can form the second cover wall of the chain case. In particular, it is possible for the first cover wall and the second cover wall to each run in a YZ plane, in particular substantially parallel to one another, and to be spaced from one another in the X direction by a distance that is slightly, for example by 10% to 20%, greater than the transverse extent of the timing chain.The timing chain can therefore run along the two cover walls without sliding contact with the first cover wall and the second cover wall.

[0011] The actuator can, for example, be a valve and / or a flap for opening and / or closing the line leading to or away from the combustion engine. For this purpose, the actuator can comprise a drive motor and / or the associated mechanical actuators.

[0012] The support body can reinforce and stiffen the chain case, at least in the area of ​​the attachment point, so that, with the help of the support body in the area of ​​the attachment point, the chain case can withstand higher loads, particularly impact forces imposed in a crash, without undergoing plastic deformation. In principle, it is possible to design the support body in the manner of a crash box in order to dissipate impact energy through deformation work through a deliberate plastic deformation of the support body. Preferably, the support body is designed as a rigid body, the strength of which corresponds approximately, for example, to + / - 20% of the strength of the actuator.

[0013] The stop point of the first cover wall can be a surface area of ​​the first cover wall against which the actuator would strike in the event of a frontal impact of the motor vehicle. In principle, it is possible to provide multiple actuators, each of which could strike a different stop point of the first cover wall in the event of a crash. Preferably, a separate support body can be provided at two or more, in particular all, stop points.

[0014] An X-direction is understood to be a coordinate direction along a longitudinal axis of a motor vehicle when the cylinder head assembly is installed in the motor vehicle. The X-direction runs essentially horizontally when the motor vehicle is parked on a flat, horizontal surface. A Y-direction is understood to be a coordinate direction along a transverse axis of a motor vehicle when the cylinder head assembly is installed in the motor vehicle. The Y-direction runs essentially horizontally when the motor vehicle is parked on a flat, horizontal surface. A Z-direction is understood to be a coordinate direction along a vertical axis of a motor vehicle when the cylinder head assembly is installed in the motor vehicle. The Z-direction runs essentially vertically when the motor vehicle is parked on a flat, horizontal surface.The X-direction, the Y-direction, and the Z-direction are orthogonal to each other. An XY plane is a plane spanned by the X-direction and the Y-direction and arranged at a specific height in the Z-direction. An XZ plane is a plane spanned by the X-direction and the Z-direction and arranged at a specific width in the Y-direction. A YZ plane is a plane spanned by the Y-direction and the Z-direction and arranged at a specific length in the X-direction.

[0015] In particular, the first cover wall is made of sheet metal. This makes the production of the first cover wall, and in particular of the chain case, simple and cost-effective. For example, a shell of the chain case forming the first cover wall can be produced by non-cutting bending of a semi-finished product punched from the sheet metal.

[0016] Preferably, the material thickness and / or dimensional stability of the first cover wall is dimensioned to retain lubricating oil and for mechanical attachment to a cylinder head of the internal combustion engine. The sheet metal can, in particular, have a particularly thin material thickness d of, for example, d ≤ 3 mm, in particular d ≤ 2 mm, preferably d ≤ 1 mm, and particularly preferably d ≤ 0.5 mm. The strength desired in a crash situation is not provided by the first cover wall, but by the support body provided in the chain case.

[0017] Particularly preferably, the second cover wall is formed by / the cylinder head of the internal combustion engine. The material requirements for the chain case can be further reduced by functionalizing an outer side of the cylinder head as the second cover wall of the chain case. As a result, the second cover wall, which coincides with the corresponding outer side region of the cylinder head, has a particularly high level of stability and strength, allowing the impact forces introduced via the actuator during a crash to be easily dissipated without additional support elements. The cylinder head, and thus the second cover wall, are manufactured in particular from metal casting, preferably cast steel or cast aluminum.

[0018] In particular, the actuator has a housing for enclosing an actuating mechanism, wherein the housing has a higher strength than the stop point of the first cover wall. The rather delicate actuating mechanism and / or an electric drive motor can be securely accommodated in the comparatively robust housing of the actuator and protected from damage in the event of a crash. Although the housing can have significantly greater stability and strength than the stop point of the first cover wall of the chain case, since the support body and not the first cover wall absorbs the impact forces in the event of a crash-related impact of the housing at the stop point, damage to the chain case caused by the impact of the housing can be avoided.

[0019] Preferably, the support body is supported on a load distribution cone formed by the second cover wall, or the support body has a load distribution cone supported on the second cover wall. The support body can be designed essentially similarly to a (compression) rod, the cross-sectional shape and cross-sectional size of which are selected such that buckling of the support body is reliably avoided under the impact forces to be expected for the design case. This allows the material used for the support body to be cost-effectively limited to what is necessary. The end of the rod-shaped part of the support body pointing towards the second cover wall can end at a tip of the load distribution cone, wherein the load distribution cone can be formed wholly or partially by the support body and / or by the second cover wall and / or can be a separate part of the multi-piece support body.Preferably, the load distribution cone is formed integrally with the support body or with the second cover wall. The impact forces transmitted by the support body to the second cover wall can thus be distributed over a larger area, thereby preventing deformation and / or plastic deformation on the side of the second cover wall.

[0020] Particularly preferably, the support body is articulated to the first cover wall at at least one connection point, particularly outside the impact point. This allows the support body to align itself automatically within certain limits when impact forces occur, in order to absorb the greatest possible proportion of the impact forces to be dissipated in the longitudinal direction of the support body. This allows the actuator to impact the impact point at a slight angle to the designated impact direction. This takes into account the fact that in the event of an accident, it is not possible to fully predict the directions in which impact forces may occur, so that the articulated mobility of the support body can enable the impact forces occurring at the impact point to be dissipated to a greater extent.

[0021] In particular, the first cover wall has, on an outer side facing the actuator, a raised portion surrounding the impact point for centering the actuator relative to the support body in the event of a crash-related impact of the actuator. This takes into account the fact that it is not possible to fully predict the directions in which impact forces may occur in an accident, so the raised portion can center the impact direction on the support body. This allows the largest possible proportion of the impact forces to be dissipated to be supported in the longitudinal direction of the support body.

[0022] Preferably, the actuator is designed to adjust an exhaust flap in an exhaust line for discharging exhaust gas from the internal combustion engine. The actuator can adjust a flow cross-section in the (exhaust) line coming from the internal combustion engine on an exhaust side of the internal combustion engine, in particular to influence the flow rate and / or flow velocity of the exhaust gas in the associated line and / or to adjust a backpressure at the outlet of the combustion cylinder during the exhaust stroke.

[0023] A further aspect of the invention relates to an internal combustion engine for a motor vehicle, comprising a cylinder head, a camshaft drive cooperating with the cylinder head, and a cylinder head assembly, which can be designed and developed as described above. The internal combustion engine can be designed and developed as explained above with reference to the cylinder head assembly. The support body, which is aligned with the position of the actuator that strikes in a crash, allows damage to the camshaft drive and the chain case of the internal combustion engine in the motor vehicle to be avoided with little effort and at low cost.

[0024] The invention will now be explained by way of example with reference to the accompanying drawings using preferred embodiments. The features presented below may represent an aspect of the invention, both individually and in combination, with the scope of protection being determined by the claims. They show: Fig. 1: a schematic perspective sectional view of a cylinder head assembly, Fig. 2: a schematic perspective sectional view of a cylinder head arrangement according to the invention before a crash and Fig. 3: a schematic perspective sectional view of the cylinder head assembly according to the invention from Fig. 2 after a crash.

[0025] The Fig. The cylinder head assembly 10 shown in Figure 1 can be used for an internal combustion engine of a motor vehicle. The cylinder head assembly 10 has a camshaft drive driven by a timing chain 12, in particular a double-row timing chain. The timing chain 12 is protected by a chain case 14, which can also retain lubricant from the timing chain 12. The chain case 14 has a front first cover wall 16 in the X direction and a rear second cover wall 18 in the X direction, between which the timing chain 12 runs. Preferably, the second cover wall 18 is formed by a cylinder head 20 produced by metal casting, of which Fig. 1 only a small part is shown

[0026] In the X direction, in front of the cylinder head 20 and in front of the chain case 14, a line 22 is provided, which may be, for example, an exhaust line leading from the internal combustion engine. A flap 24 is provided in the line, the angular position of which relative to the line 22 can be adjusted by an actuator 26. The actuator 26 has a comparatively stable housing 28 in which an actuator 30 of the actuator 26 is protected. The actuator 30 can comprise an electric servomotor and an actuating mechanism. In the event of a crash, the stable housing 28 of the actuator 26 can strike a stop point 32 of the less stable first cover wall 16 and introduce impact forces.

[0027] As in Fig. 2, the actuator 26 is positioned at a distance from the first cover wall 16 prior to a crash of the motor vehicle. However, if a crash, for example a frontal impact, of the motor vehicle occurs, it is possible that due to plastic deformations in the front section of the motor vehicle, the actuator 26 with its robust housing 28 strikes the stop point 32 of the first cover wall 16 with significant impact forces, as shown in Fig.3. Around the designated stop point 32, a substantially circular elevation 34 can be formed, for example, which can bring about a certain centering effect for the actuator 26 when it strikes the stop point 32. In the area of ​​the stop point 32, a support body 36 is provided, which can absorb the impact forces introduced at the stop point 32 by the actuator 26 and, in particular via a load distribution cone 38, can support them on the second cover wall 18. In the illustrated embodiment, the support body 36 is articulated to the first cover wall 16, for example at two or three points offset from one another in the Z direction, each about a pivot axis running in the Y direction. The second cover wall 18, in turn, can be supported, preferably flat, on the cylinder head 20 or can be formed by the cylinder head 20 itself.This prevents the first cover wall 16 from being indented, the timing chain 12 from becoming jammed between the cover walls 16, 18, and other damage to the camshaft drive. Instead, the impact forces of the actuator 26 can be supported by the support body 36, bypassing the timing chain 12 and, given the low structural strength of the first cover wall 16, without significant deformation of the camshaft case 14.

Claims

[1] Cylinder head arrangement (10) for an internal combustion engine of a motor vehicle, with a timing chain (12) for a camshaft drive of the internal combustion engine, a chain case (14) for covering the timing chain (12), wherein the chain case (14) has a first cover wall (16) and a second cover wall (18) spaced from the first cover wall (16) at least over a transverse extent of the timing chain (12), an actuator (26) positioned adjacent to the first cover wall (16) for influencing a flow rate of a line (22) communicating with the internal combustion engine, and a support body (36) connected to the first cover wall (16) and the second cover wall (18) and running past the timing chain (12) for providing a load transfer path between the actuator (26) and the second cover wall (18) in the event of a crash-related impact of the actuator (26) on a stop point (32) of the first cover wall (16). [2] Cylinder head assembly (10) according to claim 1, wherein the first cover wall (16) is made of a sheet metal. [3] Cylinder head assembly (10) according to claim 1 or 2, wherein a material thickness and / or dimensional stability of the first cover wall (16) is dimensioned to retain lubricating oil and to mechanically fasten to a cylinder head (20) of the internal combustion engine. [4] Cylinder head arrangement (10) according to one of claims 1 to 3, wherein the second cover wall (18) is formed by a / the cylinder head (20) of the internal combustion engine. [5] Cylinder head arrangement (10) according to one of claims 1 to 4, wherein the actuator (26) has a housing (28) for enclosing an actuating mechanism, wherein the housing (28) has a higher strength than the stop point (32) of the first cover wall (16). [6] Cylinder head arrangement (10) according to one of claims 1 to 5, wherein the support body (36) is supported on a load distribution cone (38) formed by the second cover wall (18) or the support body (36) has a load distribution cone (38) supported on the second cover wall (18). [7] Cylinder head arrangement (10) according to one of claims 1 to 6, wherein the support body (36) is hingedly attached to the first cover wall (16) at at least one connection point. [8] Cylinder head arrangement (10) according to one of claims 1 to 7, wherein the first cover wall (16) has, on an outer side facing the actuator (26), a raised portion (34) surrounding the stop point (32) for centering the actuator (26) relative to the support body (36) in the event of a crash-related impact of the actuator (26). [9] Cylinder head arrangement (10) according to one of claims 1 to 8, wherein the actuator (26) is designed to adjust an exhaust flap (24) in an exhaust line (22) for discharging exhaust gas from the internal combustion engine. [10] Internal combustion engine for a motor vehicle, comprising a cylinder head (20), a camshaft drive cooperating with the cylinder head and a cylinder head arrangement (10) according to one of claims 1 to 9.

Images