Patent Application
20180112623
The invention relates to a cylinder head with connected exhaust manifold of an internal combustion engine.
In one generally known arrangement, the cylinder head has, after the outlet valve, an exhaust duct that ends on an outer cylinder head connecting face. An exhaust manifold with an assigned exhaust manifold connecting face is connected by a screw joint to this cylinder head connecting face such that the exhaust duct of the cylinder head is continued in the exhaust manifold.
An exhaust manifold seal is fitted between the cylinder head connecting face and the exhaust manifold connecting face for an exhaust gas-impervious connection of the exhaust manifold to the cylinder head. Coolant ducts through which a coolant flows in the cylinder head lie in the region of the exhaust duct. Depending on the number of cylinders of the internal combustion engine and their arrangement, a cylinder head has a plurality of exhaust ducts to which in each case exhaust manifolds of an exhaust gas collector are connected.
In the case of a generic internal combustion engine, the hot exhaust gas is conducted via the exhaust duct into the exhaust manifold, possibly into a turbocharger and then further via silencers into the atmosphere. In the case of a normally fluid-cooled internal combustion engine, a large amount of heat energy is discharged into the cooling medium flowing through the cylinder head. As a result, components close to the exhaust duct can be loaded in a thermally inadmissible manner and possibly damaged. Moreover, as a result, energy is removed from the exhaust gas, which energy could be used by energy conversion, for example, in a downstream exhaust gas turbocharger.
Measures are already known in the prior art by which such thermal loading is reduced. In the case of a first known measure, a thermally insulating coating is applied to the inner wall of the outlet duct (NEMAK GmbH). In the case of a different measure which is also supposed to reduce the thermal load, the exhaust duct in the cylinder head is embodied entirely in ceramic. These are clearly disadvantageously complex, costly solutions. Moreover, separate exhaust manifold seals must also be provided here independently of the desired reduction in thermal loading for the exhaust gas-impervious connection of an exhaust manifold.
An object of one aspect of the invention is, by a simple, low-cost solution, to reduce the thermal load in the region of an exhaust duct of the cylinder head and also make available a simple, low-cost exhaust manifold seal.
According to one aspect of the invention, a cylinder head with a connected exhaust manifold of an internal combustion engine is provided. The cylinder head has at least one exhaust duct that ends at an outer cylinder head connecting face to which the exhaust manifold, which forms a continuation of the exhaust duct, is connected with an assigned exhaust manifold connecting face, preferably by at least one screw connection. According to one aspect of the invention, a flange bushing insert comprising a bushing part and an end-side flange part is inserted into the exhaust duct of the cylinder head. The bushing part has at least one radially protruding, circumferential bead as a spacer and sealing element with which the bushing part bears against the exhaust duct inner wall. The flange part projects in an annular disc shape radially at the outer end of the flange bushing and is clamped imperviously between the cylinder head connecting face and the exhaust manifold connecting face, and indeed is preferably clamped as a sealing flange, highly preferably clamped as a sealing flange and for axial bushing fixing, in such a manner that a circumferential insulating gap, which is uncoupled from an exhaust gas flow and is thermally insulating with a gap width corresponding to the bead height, is formed between the exhaust duct inner wall and the bushing part outer wall as well as between the flange part and an axially adjacent bead and/or between two beads lying axially next to one another.
The simply formed flange bushing insert, which can be produced at low cost, advantageously has two functions, namely thermal insulation of the exhaust duct as well as sealing of the exhaust manifold. Here, these two functions are integrated in a single component with advantages in terms of production, procurement, logistics and assembly.
With a bushing part length extending over the entire exhaust duct length of the cylinder head, possibly also already with a partial length, a thermal insulation of the exhaust duct in the cylinder head is achieved, with which its thermal loading can be significantly reduced. It is thus achieved that on one hand less heat energy can be discharged via the cooling medium so that the dimensions of a cooling system can be advantageously reduced as a result. On the other hand, as a result of the thermal insulation, more heat energy remains in the exhaust gas, which can be used for increased energy conversion in particular in an exhaust gas turbocharger.
A further advantage lies in the fact that, as a result of the flange part fixed in a sealing manner between the exhaust duct and the exhaust manifold, the bushing part connected thereto is also fixed in an axially non-displaceable and rotationally conjoint manner in the exhaust duct.
Thermal insulation is carried out here substantially by the principle of air gap insulation in the insulating gap.
Instead of air, at least in partial regions of the insulating gap on the bushing part outer wall, a thermal insulating element and/or material, preferably in the insulating gap width, can also alternatively be fitted, in particular as a coating and/or as a pushed-on insulating material bushing and/or as e.g. pushed-on insulating material shell(s).
The flange bushing insert is expediently produced in one piece and/or of uniform material from a heat-resistant and/or elastic material, in particular from a metallic substance.
According to a further particularly preferred configuration, at least one bead can be arranged in the axial bushing part end region opposite the flange part for formation of an insulating gap, which is as axially long as possible.
According to a further particularly preferred configuration, the bushing part length corresponds where possible to the exhaust duct length in the cylinder head.
According to a particularly preferred concrete configuration and in particular for an exact arrangement and/or fixing, the flange part lies in an annular groove of the cylinder head connecting face.
As already mentioned above, the flange part is clamped between the cylinder head connecting face and the exhaust manifold connecting face preferably as a sealing flange or as a sealing flange and for axial bushing fixing. To this end, according to a first embodiment, it can be provided that the flange part is supported axially with at least one circumferential, preferably elastically formed bead on the cylinder head connecting face, preferably in the annular groove of the cylinder head connecting face. Here, the flange part preferably projects axially in the direction of the exhaust manifold or protrudes so that it clamps the flange part as a sealing element during mounting. In an alternative configuration to this, however, a sealing ring which protrudes, in particular projects, in the direction of the exhaust manifold can also be provided on the flange part. A combination of both configurations (bead and sealing ring) is also in principle possible.
Thermal insulation of an exhaust duct with the flange bushing insert according to one aspect of the invention can be used in particular in the case of an internal combustion engine of a vehicle, in particular of a utility vehicle.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
The invention will be explained in greater detail further by way of example on the basis of a schematic drawing.
A longitudinal section through an exhaust duct 1 of a cylinder head 2 of an internal combustion engine is represented in
Exhaust duct 1 ends at an outer cylinder head connecting face 6, to which here, by way of example by several screw connections or screw joints 7, an exhaust manifold 8 is connected in an exhaust gas-impervious manner with its assigned exhaust manifold connecting face 9.
A flange bushing insert 10, which is represented in an enlarged form with further details in
Here, flange bushing insert 10 is constructed from a bushing part 11 and an end-side flange part 12.
In a first embodiment according to
In a second, alternative embodiment according to
By way of example here in the case of the two embodiments according to
With flange bushing insert 10, here, two functions, namely the thermal insulation of exhaust duct 1 with bushing part 11 and sealing of exhaust manifold 8 with flange part 12, are combined in a single component, the production and mounting of which is possible in a very simple manner.
Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102016012719.8 | Oct 2016 | DE | national |
