AT523188A1 - CYLINDER HEAD FOR A COMBUSTION ENGINE - Google Patents

Abstract

The invention relates to cylinder head (1) and a method for manufacturing a cylinder head (1) with at least one skeleton (12) made of a base material with a fire deck (F) which is designed for connection to a cylinder block of the internal combustion engine, whereby the cylinder block and cylinder head (1) at least one combustion chamber (2) is formed, and at least one cooling jacket (8) close to the combustion chamber is arranged adjacent to the combustion chamber (2), with an insert (4) made of a second material - in particular to reinforce the cylinder head (1) Forms parts of the cylinder head (1). The object of the present invention is to specify a more cost-effective and improved cylinder head (1). This object is achieved according to the invention in that the at least one cooling jacket (8) close to the combustion chamber is at least partially limited by the insert (4) and that the insert (4) is connected to the skeleton (12) of the cylinder head (1) via a joining process .

Description

The invention relates to a cylinder head for an internal combustion engine with at least one skeleton made of a base material with a fire deck which is designed for connection to a cylinder block of the internal combustion engine, at least one combustion chamber being formed by the cylinder block and cylinder head, and at least one cooling jacket close to the combustion chamber adjacent to the combustion chamber is arranged, wherein - in particular to reinforce the cylinder head - a

Inlay made of a second material forms parts of the cylinder head.

The invention also relates to a method for manufacturing such a cylinder head.

A skeleton is understood here to mean a base body that forms part of the cylinder head either inside the cylinder head or, in the sense of an exoskeleton, on the outside. The insert can be permanently or permanently connected to the base body. It is primarily used for reinforcement and takes on functions

the power line and the like.

Such inserts as they are used in the cylinder head in question are shown, for example, in DE 10 2004 053 362 A1. From this, a reinforcing component for a cylinder head is known, which is cast into a skeleton made of an aluminum-containing material of the cylinder head for reinforcement. In addition, the walls of cavities can be coated with a second material and thus also reinforced. The insert is used to achieve high rigidity with a lower weight of the cylinder head. The insert is cast into the skeleton made of the light metal aluminum. However, this results in the disadvantage that a casting process has to be carried out again after the process of casting the skeleton. Therefore, all cores for the recesses provided in the skeleton must be attached. This causes considerable effort in production and significantly limits the freedom of design. Wall thicknesses can also vary greatly due to the nature of the manufacturing process. In order to achieve the required accuracies, a strongly increasing effort is necessary. This subsequently leads to greater expenditure of time and increasing costs. In the event of errors in the manufacture of the insert, the entire cylinder head is also defective and accordingly

to be eliminated.

The object of the present invention is a more cost-effective and

specify improved cylinder head.

According to the invention, this is achieved in that the at least one cooling jacket near the combustion chamber is at least partially delimited by the insert, and that the insert is connected to the skeleton of the cylinder head via a joining process. The insert is manufactured separately and, with regard to its outer surfaces and inner surfaces, can meet the required accuracy for the flows of the fully assembled internal combustion engine. The assembly by joining production step, which is downstream of the casting, enables the high degree of accuracy, which is particularly required in the area of the fire deck

can be achieved without further reworking.

The object is also achieved by the above method according to the invention in that the insert is joined to the skeleton of the cylinder head using a joining method

is put together.

A joining process is understood to mean processes in which at least two individual components, two individual parts, are joined together in a solid state. Pouring is not a joining process and the inlay does not go into the skeleton

poured.

Casting errors usually only affect the respective component and not the entire cylinder head, which leads to a reduction in rejects in production.

It is particularly advantageous if the insert is connected to the skeleton of the cylinder head either via a press connection or material connection. To produce a press connection, the insert and the skeleton have an interference fit. In an associated method, the insert is pressed into the skeleton of the cylinder head or the skeleton is pressed into the insert. The connection via material connection is carried out, for example, by welding or soldering with an auxiliary material. In the process of manufacturing the cylinder head, the insert is connected to the skeleton in a materially bonded manner. The joining processes used are characterized by the production of precise and permanent connections that can withstand even high loads. But also connections that are made by hybrid joining,

can be used. In thermally uncritical areas away from the fire deck, bonding is even possible, especially in combination with another form of connection

possible.

Valve seats are usually separate parts that are used in the cylinder head for contact with valve plates to close gas exchange channels. This should enable better wear properties, higher strength and an improved sealing surface between the valve head and the valve seat. In a special embodiment of the cylinder head, in contrast to conventional cylinder heads, it is provided here that the insert forms valve seats of the cylinder head. This results in improved heat dissipation and better mechanical stress distribution in the entire cylinder head compared to separate valve seats. The detachment of the valve seat from the cylinder head is also prevented by the enlarged contact area between the skeleton and the valve seat. In addition, larger valve diameters and lower pressure losses can be achieved by reducing the flow coefficient. The reduction of the flow coefficient is made possible by the reduction of the sharp edges in the area of the wall and by the possibility of using smaller wall thicknesses. Laminar flow would occur at sharp edges

peel off.

To improve the tightness, it is provided in a particularly advantageous embodiment that the insert has a sealing surface for supporting a

Has cylinder head gasket.

It is favorable if the insert has ribs or at least a rib structure for reinforcement. In this way, a higher resistance can be opposed to deformation. This also prevents the insert from being detached from the skeleton due to deformation due to the influence of forces on the insert. Due to the ribs or the rib structure, higher mechanical loads can be absorbed by the cylinder head and higher ignition pressures are possible. The stiffening leads to better absorption and better distribution of the

mechanical loads resulting from the ignition pressure.

A particularly advantageous cylinder head can be achieved if the insert is completely sealed off from the skeleton with regard to the coolant. Thereby

leakages can be completely avoided.

With regard to cooling by forced convection of the cylinder head, it is particularly favorable if the insert has ribs or at least one rib structure in the area of the cooling jacket for guiding a coolant flow. The surface in contact with a coolant is also increased in this way and the heat dissipation from the cylinder head into the coolant can be significant

can be increased.

Because the cooling jacket near the combustion chamber is integrated in the insert, a cooling jacket that is completely sealed off from the skeleton is achieved. With the additional rib structure described above or the ribs into the interior of the cooling jacket, the coolant flow is optimally guided and slides and the coolant can be better distributed. In addition, this measure leads to lower pressure losses in the coolant circuit and thus to an overall improved cooling. This then leads to lower cylinder head temperatures.

In order to achieve the most homogeneous behavior possible of the various components and to reduce the different behavior of the materials due to the different material properties, it is advantageous if the insert has a wall thickness that is a maximum of 2 mm and preferably between

1.5 mm and 2 mm. As a result of this small extent, deformation paths in the event of external mechanical loading or due to thermal loading are still so small that they are caused by the mechanical connection between the skeleton

and deposit are compensated.

It is particularly advantageous if the insert delimits the combustion chamber.

The positive effects of the insert can also be increased if the insert forms an antechamber.

By integrating the prechamber and / or the combustion chamber in the insert, the wall thicknesses of the cylinder head can be greatly reduced, larger valve diameters can be implemented, the areas required for seals are reduced, and the overall component temperatures are reduced and the thermal stresses that occur as a result are reduced. As a result, the overall wall thickness in the cylinder head can be reduced. The absorption of higher ignition pressures and larger mechanical loads is possible.

It is favorable if the insert forms at least parts of gas exchange channels and preferably completely surrounds the gas exchange channels in the area of a fire deck of the cylinder head. This means that there is less heat input in

reached the skeleton of the cylinder head.

The insert advantageously extends as far as an exhaust gas duct to a turbocharger, which is flow-connected to the combustion chamber via the charge exchange channels or can be flow-connected through the gas exchange valves. This exhaust gas routing is usually referred to as a port liner. In this embodiment, a lower heat input from the exhaust gas into the skeleton is achieved. A higher degree of insulation is possible and the heat energy passed on to the turbocharger is higher due to the reduced heat losses along the gas exchange channels.

The positive effect is intensified when the skeleton is made of a light metal and

preferably consists of an aluminum or an aluminum alloy.

It is particularly advantageous if the insert has a combustion chamber stopper, the combustion chamber stopper being designed essentially as a hollow cylinder which merges at its base into a main body of the insert, the combustion chamber stopper being in one piece and in one piece with the main body of the insert is carried out and preferably has a height between 100 to 200 µm.

This has the advantage that the combustion can be better controlled and limited to the combustion chamber. Combustion chamber stoppers come with a similar one

Function such as piston rings too.

To achieve an insulation effect, it is provided in a special embodiment that the second material has a lower thermal conductivity than the base material, the second material preferably being steel.

With regard to the mechanical behavior, it is advantageous if the second material has a higher modulus of elasticity than the base material, the second

The material is preferably steel.

These material properties are not only used by steel, but also by many

other materials used as a pure substance or as an alloy

can be. For example, in an alternative embodiment, a

Ceramic insert can be provided.

It is advantageous if the base material is aluminum or an aluminum alloy. As a result, the skeleton of the cylinder head can be manufactured in the usual, tried and tested and inexpensive way and the skeleton is due to the low

The density of aluminum is correspondingly of a lower mass.

A particularly high quality of the insert with high accuracy can be achieved if the insert is produced by an additive direct metal printing process.

Similarly high requirements are met by the insert if it is through

Investment casting is produced.

The invention also relates to an insert for a cylinder head with a skeleton made of a base material, in particular for reinforcement, the insert being formed from a second material, the insert having at least one cooling jacket

partially limited, which is designed as a cavity in the insert.

In a first embodiment, the insert has valve seats.

Furthermore, the insert can be a sealing surface to support a cylinder head gasket

exhibit.

It is more favorable if the insert has ribs or at least one rib structure for stiffening and / or if the insert has a wall thickness between 1.5 mm

and 2 mm.

From the point of view of thermal properties, it is more favorable if the insert delimits a combustion chamber and / or if the insert forms an antechamber and this

limited.

It is advantageous if the insert forms at least parts of gas exchange channels.

In order to locally limit the harmful volume caused by the combustion in the combustion chamber, it is provided in certain versions that the insert has a

Has combustion chamber stopper.

In order to keep the exhaust gas at a high entropy level for the turbocharger, it is advantageous if the second material has a lower thermal conductivity than aluminum, the second material preferably being steel, since this reduces heat losses through heat transfer through the base material

become.

From a mechanical point of view, it is advantageous if the second material has a higher modulus of elasticity than aluminum, the second material preferably being steel.

The insert can be made by an additive direct metal printing process or by

Investment casting are produced.

In the following, the invention is based on the non-restrictive embodiment

described in more detail in the figures. Show it:

1 shows a cylinder head according to the invention in a view of a fire deck;

2 shows an insert of the cylinder head according to the invention in a top view;

3 shows the cylinder head in a section along the line III-III] according to FIG. 1;

4 shows the cylinder head in a section along the line IV-IV according to FIG. 1; and

FIG. 5 shows the cylinder head in a section along the line V-V according to FIG. 1.

In Fig. 1, a cylinder head 1 is shown in a view from a fire deck F from. The delimitation of a combustion chamber 2 by the cylinder head 1 can be seen. In addition, four gas exchange ducts 3 can be seen for a cylinder not shown in detail. For better visibility of the details around the gas exchange channels

3 are not poppet valves for closing the gas exchange ducts 3

drawn.

In the cylinder head 1 shown, of these four gas exchange ducts 3, two ducts are provided as inlet ducts and two ducts as exhaust ducts. This number and arrangement of the gas exchange channels 3 for introducing a fuel into the combustion chamber 2 is only an example to explain the principle of the invention. The invention can also be applied to any other number and

Find the arrangement of the gas exchange channels 3 use.

Fig. 2 shows an insert 4 of the cylinder head 1 according to the invention in a plan view. In this case, valve seats 5 for the support of the poppet valves (not shown) are formed by the insert 4. At the valve seat 5 is sealed between the cylinder head 1 and the poppet valve around the inlet and outlet of the fuel and thus the

To interrupt fluid flow.

The insert 4 has ribs 6 for stiffening and for guiding a coolant flow 7. The coolant flow 7 is sketched schematically with dashed arrows.

The insert 4 forms a cooling jacket 8 close to the combustion chamber, which is completely integrated in the insert 4. Coolant flows through the cooling jacket 8 along the arrows with the reference number 7. Coolant enters at three points from the outside in an approximately radial direction to a center Z. The coolant is guided along the ribs 6 and flows around the area of the valves in a favorable manner either along an area of the valve bridges 9 or in the circumferential direction past a valve on the outside. The three inlets are here arranged as an extension of the valve bridges 9. A coolant outlet 11 is provided opposite a central coolant inlet 10. Part of the coolant that flows in through this central coolant inlet 10 flows approximately in a straight line to the center Z and from there in a straight line to the coolant outlet 11.

The deflection of the coolant flow 7 from the central coolant inlet 10 and from the other two coolant inlets into the peripheral areas is achieved in each case by the curvature of the ribs 6 and the arrangement of the ribs 6. A part of the ribs 6 achieves the deflection of part of the coolant flow 7

Outside.

From the central coolant inlet 10, a large part of the coolant flow 7 is guided through the ribs 6, which curve outward from the coolant inlet 10, to the center Z.

In an alternative embodiment, the insert has a rib structure. The ribs are not unique and formed alone, but a multitude of

smaller ribs are arranged side by side.

The coolant outlet 11 is arranged on the side of the two outlet channels, which here in the embodiment shown each have a larger channel diameter than the two inlet channels.

A skeleton 12 of the cylinder head 1 can be seen in FIG. 3. The arrangement of the insert 4 can also be seen in detail from FIG. 3. A so-called port liner 4a is formed by the insert 4 around an outlet channel 3a. The portliner 4a serves to reduce the heat dissipation from the outlet duct 3a to the cylinder head 1 and to increase the energy that can be used in the exhaust gas turbocharger. In addition, the insert 4 increases the maximum temperatures that can be tolerated by the cylinder head 1 and at the same time reduces the dimensions required for this.

In the embodiments shown, the skeleton 12 consists of a base material which is advantageously aluminum or an aluminum alloy. The insert 4 is advantageously made of steel. This combination of steel and aluminum or steel and aluminum alloy is an advantageous one. Alternatively, other material combinations are also possible.

The valve seats 5 for the inlet channels and the outlet channels 3 a are also completely formed by the insert 4.

In the embodiment shown, the insert 4 has a wall thickness of 1.5 mm. But wall thicknesses of up to 2 mm are possible in other designs.

Enclosed by the insert 4, the cooling jacket 8 is arranged around the charge exchange ducts 3 and around an ignition device 13. For this purpose, the coolant is transferred from the skeleton 12 through a water passage 14 into the cooling jacket 8 in the insert 4

initiated.

Ribs 6 can be seen in FIG. 4. In addition, an optional antechamber V is indicated schematically in FIG. 4. The cavity that forms the antechamber V is completely surrounded by the insert 4.

An optional lateral fuel injector I is also indicated schematically.

The exact appearance of the ribs 6 can be seen in FIG. 5. The cooling jacket 8 is formed by the resulting cavities in the insert 4 and its ribs 6.

A combustion chamber stopper 15 is indicated with a dashed line for alternative designs. This limits the dead space of the combustion in the combustion chamber 2. The combustion chamber stopper 15 adjoins the connection surface of the cylinder head 1, which is designed as a sealing surface 16, on a cylinder block (not shown). This sealing surface 16 here closes off the base body of the insert 4, which then merges into the body of the combustion chamber stop 15. The combustion chamber stopper 15 has a height H of 100 to 200 μm.

Claims (1)

PATENT CLAIMS Cylinder head (1) for an internal combustion engine with at least one skeleton (12) made of a base material with a fire deck (F) which is designed for connection to a cylinder block of the internal combustion engine, at least one combustion chamber (2) being formed by the cylinder block and cylinder head (1) and at least one cooling jacket (8) close to the combustion chamber is arranged adjacent to the combustion chamber (2), an insert (4) made of a second material forming parts of the cylinder head (1), in particular to reinforce the cylinder head (1), characterized in that that the at least one cooling jacket (8) close to the combustion chamber is at least partially limited by the insert (4), and that the insert (4) is connected to the skeleton (12) of the cylinder head (1) via a joining process. Cylinder head (1) according to claim 1, characterized in that the insert (4) with the skeleton (12) of the cylinder head (1) via a Press connection is connected. Cylinder head (1) according to Claim 1, characterized in that the insert (4) has a material connection with the skeleton (12) of the cylinder head (1) connected is. Cylinder head (1) according to one of Claims 1 to 3, characterized in that the insert (4) forms valve seats (5) of the cylinder head (1). Cylinder head (1) according to Claim 1 or 4, characterized in that the insert (4) has a sealing surface (16) for supporting a cylinder head gasket having. Cylinder head (1) according to one of claims 1 to 5, characterized in that the insert (4) ribs (6) or at least one Has rib structure for stiffening. Cylinder head (1) according to one of Claims 1 to 6, characterized in that the insert (4) is completely sealed off from the skeleton (12) with regard to the coolant. 11. 12th 13th 14th 15th 12th Cylinder head (1) according to one of claims 1 to 7, characterized in that the insert (4) in the region of the cooling jacket (8) has ribs (6) or at least one rib structure for guiding a coolant flow (7). Cylinder head (1) according to one of Claims 1 to 8, characterized in that the insert (4) has a wall thickness which is a maximum of 2 mm and preferably between 1.5 mm and 2 mm amounts to. Cylinder head (1) according to one of Claims 1 to 9, characterized characterized in that the insert (4) delimits the combustion chamber (2). Cylinder head (1) according to one of Claims 1 to 10, characterized in that the insert (4) forms an antechamber (V). Cylinder head (1) according to one of claims 1 to 11, characterized in that the insert (4) forms at least parts of gas exchange ducts (3) and preferably the gas exchange ducts (3) in the area of a fire deck (F) of the cylinder head (1) fully included. Cylinder head (1) according to one of claims 1 to 12, characterized in that the insert (3) has a combustion chamber stopper (15), the combustion chamber stopper (15) being designed essentially as a hollow cylinder, which on its base surface seated on a base body of the insert (4), the combustion chamber stopper (15) being made in one piece and in one piece with the base body of the insert (4) and preferably having a height (H) between 100 to 200 µm. Cylinder head (1) according to one of Claims 1 to 13, characterized in that the second material has a lower thermal conductivity than the base material, the second material preferably being steel. Cylinder head (1) according to one of claims 1 to 14, characterized in that the second material has a higher modulus of elasticity than comprises the base material, the second material preferably being steel is 16. Cylinder head (1) according to one of claims 1 to 15, characterized in that the base material is aluminum or a Aluminum alloy is. 17. A method for manufacturing a cylinder head (1) according to one of claims 1 to 16, characterized in that the insert (4) with the skeleton (12) of the cylinder head (1) is assembled. 18. The method according to claim 17, characterized in that the insert (4) is pressed into the skeleton (12) of the cylinder head (1) or that the skeleton (12) is pressed into the insert (4) to produce a press connection between the skeleton (12) and insert (4). 19. The method according to claim 17, characterized in that the insert (4) is materially connected to the cylinder head (1). 20. The method according to any one of claims 1 to 19, characterized in that the insert (4) by an additive direct metal printing process will be produced. 21. A method for manufacturing a cylinder head (1) according to any one of claims 1 to 19, characterized in that the insert (4) is made by investment casting will be produced. 06.12.2019 WR