DE202014100385U1 - Cylinder head with cooled turbine - Google Patents

Abstract

Cylinder head with cooled turbine (1), in which
The cylinder head has at least one cylinder,
- Each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder and connects to each outlet opening an exhaust pipe, the at least one exhaust pipe at least one cylinder in an inlet region (4) of the turbine (1) opens, leading into a flue gas flow channel (5) passes, and
- The turbine (1), which comprises at least one in a turbine housing (3) on a rotatable shaft (7) mounted impeller (6) for forming a cooling at least one in the housing (3) integrated coolant channel (8) through at least one wall (2) is limited and formed,
characterized in that
- The at least one the at least one coolant channel (8) delimiting wall (2) is at least partially provided with a thermal insulation (2a).

Description

• – der Zylinderkopf mindestens einen Zylinder aufweist,
• – jeder Zylinder mindestens eine Auslassöffnung zum Abführen der Abgase aus dem Zylinder aufweist und sich an jede Auslassöffnung eine Abgasleitung anschliesst, wobei die mindestens eine Abgasleitung mindestens eines Zylinders in einen Eintrittsbereich der Turbine mündet, der in einen Abgas führenden Strömungskanal übergeht, und
• – die Turbine, welche mindestens ein in einem Turbinengehäuse auf einer drehbaren Welle gelagertes Laufrad umfasst, zur Ausbildung einer Kühlung mindestens einen im Gehäuse integrierten Kühlmittelkanal aufweist, der durch mindestens eine Wandung begrenzt und ausgebildet ist.

The invention relates to a cylinder head with a cooled turbine, in which

• The cylinder head has at least one cylinder,
• - Each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder and connects to each outlet opening an exhaust pipe, wherein the at least one exhaust pipe of at least one cylinder opens into an inlet region of the turbine, which merges into a flow channel leading to exhaust gas, and
• - The turbine, which comprises at least one mounted in a turbine housing on a rotatable shaft impeller to form a cooling at least one integrated in the housing coolant channel which is bounded and formed by at least one wall.

Internal combustion engines have a cylinder block and at least one cylinder head, which is used to form at least one cylinder, d. H. Combustion chamber, are connected to each other at their mounting end faces.

The cylinder block has a corresponding number of cylinder bores for receiving the pistons or the cylinder tubes. The pistons are guided axially movably in the cylinder tubes and, together with the cylinder tubes and the cylinder head, form the combustion chambers of the internal combustion engine.

The cylinder head is usually used to hold the valve train. To control the charge cycle, an internal combustion engine requires controls and actuators to operate the controls. As part of the charge exchange, the exhaust of the combustion gases via the outlet openings and the filling of the combustion chamber, d. H. the intake of the fresh mixture or the charge air, via the inlet openings. To control the charge cycle, four-stroke engines use almost exclusively globe valves as control members, which perform an oscillating lifting movement during operation of the internal combustion engine and in this way release and close the inlet openings and outlet openings. The required for the movement of the valves valve actuating mechanism including the valves themselves is referred to as a valve train.

The inlet ducts leading to the inlet openings and the outlet ducts, d. H. the exhaust pipes, which adjoin the outlet openings are at least partially integrated in the cylinder head according to the prior art. The exhaust pipes of the exhaust ports of a single cylinder are usually - within the cylinder head - merged into a cylinder associated with the partial exhaust line before these partial exhaust gas lines - often to a single overall exhaust line - are merged. The combination of exhaust pipes to an overall exhaust line is generally and in the context of the present invention referred to as exhaust manifold.

Downstream of the at least one manifold, the exhaust gases are then fed to a turbine, for example, the turbine of an exhaust gas turbocharger, and optionally passed through one or more exhaust aftertreatment systems.

The manufacturing costs for the turbine are comparatively high, since the material used for the thermally highly stressed turbine housing - often nickel-containing - material is expensive, especially in comparison to the material preferably used for the cylinder head; for example aluminum. Not only the material costs per se are comparatively high, but also the costs for the processing of these materials used for the turbine housing.

It follows from the foregoing that it would be extremely advantageous in terms of cost to provide a turbine that could be made from a less expensive material such as aluminum or gray cast iron.

The use of aluminum would also be advantageous in terms of the weight of the turbine. In particular, when it is considered that a close-coupled arrangement of the turbine leads to a relatively large-sized, voluminous housing. Because the connection of turbine and cylinder head by means of flange and screws requires a large turbine inlet area due to the limited space, also because sufficient space must be provided for the assembly tools. The voluminous housing brings a correspondingly high weight with it. The weight advantage of aluminum over a highly resilient material is particularly evident in a turbine arranged close to the engine due to the comparatively high use of materials.

In order to use more cost-effective materials for the production of the turbine, the turbine according to the prior art with a cooling, for example, with a liquid cooling, equipped, which greatly reduces the thermal load of the turbine or the turbine housing by the hot exhaust gases and thus the Use of thermally less resilient materials allows.

In general, the turbine housing is provided to form a cooling with a coolant jacket. From the prior art both concepts are known in which the housing is a casting and the coolant jacket is formed as part of the casting process as an integral part of a monolithic housing, as well as concepts in which the housing is modular, wherein in the context of assembly a cavity is formed, which serves as a coolant jacket.

A designed according to the latter concept turbine describes, for example, the German patent application DE 10 2008 011 257 A1 , A liquid cooling of the turbine is formed by the fact that the actual turbine housing is provided with a casing, so that forms a cavity between the housing and the at least one spaced-apart formwork element, can be introduced into the coolant. The casing extended by the casing then includes the coolant jacket.

The EP 1 384 857 A2 also discloses a turbine whose housing is equipped with a coolant jacket.

The DE 10 2007 017 973 A1 describes a kit for forming a steam-cooled turbine casing.

Due to the high specific heat capacity of a liquid, in particular the water usually used, the housing by means of liquid cooling large amounts of heat can be withdrawn. The heat is released inside the housing to the coolant and removed with the coolant. The heat given off to the coolant is withdrawn from the coolant in a heat exchanger.

In principle, it is possible to equip the liquid cooling of the turbine with a separate heat exchanger or - in a liquid-cooled internal combustion engine - the heat exchanger of the engine cooling, d. H. to use the heat exchanger of another liquid cooling, for this purpose. The latter requires only appropriate connections of both circuits.

However, it should be considered in this connection that the amount of heat to be absorbed by the coolant in the turbine can be 40 kW or more if materials which are not very durable, such as aluminum, are used to produce the housing. The coolant to extract such a large amount of heat in the heat exchanger and dissipate by means of air flow to the environment turns out to be problematic.

Although modern motor vehicle drives are equipped with powerful fan motors in order to provide the air mass flow required for a sufficiently high heat transfer at the heat exchangers. But another, relevant to the heat transfer parameters, namely the surface provided for the heat transfer surface, can not be made arbitrarily large or enlarged, since the space in the front-end area of the vehicle, where the various heat exchangers usually arranged be limited.

Modern motor vehicles often have - in addition to the heat exchanger of the engine cooling - on other heat exchangers, in particular cooling devices.

On the intake side of a supercharged internal combustion engine often a charge air cooler is arranged to contribute to a better filling of the cylinder. In order to maintain a maximum permissible oil temperature, the heat release via the oil sump due to heat conduction and natural convection is often no longer sufficient, so that an oil cooler is provided in individual cases. In addition, modern internal combustion engines are increasingly being equipped with exhaust gas recirculation. The exhaust gas recirculation is a measure to counteract the formation of nitrogen oxides. In order to achieve a significant reduction in nitrogen oxide emissions, high exhaust gas recirculation rates are required, which is a cooling of the recirculated exhaust gas, d. H. require a compression of the exhaust gas by cooling. Other coolers can be provided, for example for cooling the transmission oil in automatic transmissions and / or for cooling hydraulic fluids, in particular hydraulic oil, which is used in the context of hydraulically actuated adjusting devices or for steering assistance. The air conditioning condenser of an air conditioning system is also a heat exchanger, which has to give off heat to the environment during operation, so requires a sufficiently high air flow and therefore is to be arranged in the front-end area.

Due to the very limited space in the front-end area and the large number of heat exchangers, the individual heat exchangers can not be dimensioned according to requirements.

The ability to arrange a sufficiently large heat exchanger for the liquid cooling of the turbine in the front-end area in order to dissipate incurred when using thermally less resilient materials high amounts of heat can not be given.

In the design of a cooled turbine, therefore, a compromise between cooling capacity and material is required.

In order to use more cost-effective materials for the turbine, the turbine according to the prior art can also be equipped on the exhaust side with an insulation. Such a concept discloses the international application WO 2010/039590 A1 ,

In view of the foregoing, it is the object of the present invention to provide a cooled turbine cylinder head according to the preamble of claim 1 which is optimized with respect to the turbine.

• – der Zylinderkopf mindestens einen Zylinder aufweist,
• – jeder Zylinder mindestens eine Auslassöffnung zum Abführen der Abgase aus dem Zylinder aufweist und sich an jede Auslassöffnung eine Abgasleitung anschliesst, wobei die mindestens eine Abgasleitung mindestens eines Zylinders in einen Eintrittsbereich der Turbine mündet, der in einen Abgas führenden Strömungskanal übergeht, und
• – die Turbine, welche mindestens ein in einem Turbinengehäuse auf einer drehbaren Welle gelagertes Laufrad umfasst, zur Ausbildung einer Kühlung mindestens einen im Gehäuse integrierten Kühlmittelkanal aufweist, der durch mindestens eine Wandung begrenzt und ausgebildet ist,

und der dadurch gekennzeichnet ist, dass

• – die mindestens eine den mindestens einen Kühlmittelkanal begrenzende Wandung zumindest bereichsweise mit einer Wärmeisolierung versehen ist.

This problem is solved by a cylinder head with cooled turbine, in which

• The cylinder head has at least one cylinder,
• - Each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder and connects to each outlet opening an exhaust pipe, wherein the at least one exhaust pipe of at least one cylinder opens into an inlet region of the turbine, which merges into a flow channel leading to exhaust gas, and
• The turbine, which comprises at least one impeller mounted on a rotatable shaft in a turbine housing, has at least one coolant channel integrated in the housing for forming a cooling, which is delimited and formed by at least one wall,

and which is characterized in that

• - The at least one wall defining the at least one coolant channel is at least partially provided with a thermal insulation.

According to the invention, the at least one integrated coolant channel in the turbine housing is equipped with a thermal insulation, d. H. the wall defining this coolant channel is provided-at least in some areas-with a heat insulation, d. H. coated, clad or the like. In the context of the present invention, thermal insulation relative to the housing material used is quite generally characterized in that the thermal insulation has a lower thermal conductivity than this material.

In the present case, the aim is not to dissipate the largest possible amount of heat from the housing. In contrast to this conventional objective, the cooling according to the invention is made more difficult by introducing a thermal insulation to extract heat from the housing and to cool this housing. The cooling capacity is deliberately limited and reduced by introducing insulation. The heat transmission of the heat transfer surface, d. H. the wall, is lowered, wherein also according to the invention heat is introduced from the housing into the coolant, but less than in the prior art.

By this measure, the maximum amount of heat to be dissipated is reduced or limited in an advantageous manner. This eliminates the problem of having to dissipate very large amounts of heat absorbed by the coolant in the turbine.

Corresponding to the moderate cooling capacity is to choose a corresponding material for the production of the turbine according to the invention, namely gray cast iron or steel casting or the like.

On the one hand, the concept according to the invention makes it possible to dispense with materials which are highly resistant to thermal loads, in particular nickel-containing materials, for producing the turbine housing, since the turbine is also equipped according to the invention with cooling. On the other hand, the cooling performance is not of the type that thermally only slightly resilient materials, such as aluminum, can be used.

The procedure according to the invention makes the use of cost-intensive materials unnecessary, without dissipating excessively large amounts of heat in connection with the cooling of the turbine.

Thus, the object underlying the invention is achieved, namely a cylinder head provided with a cooled turbine according to the preamble of claim 1, which is optimized with respect to the turbine.

The essential distinguishing feature of the procedure according to the invention over concepts according to the prior art, in which the housing is protected on the exhaust side by means of insulation from excessive heat input, is the fact that according to the invention the heat input into the housing or the housing material is not impeded by means of insulation or is limited. In addition, embodiments are feasible in which the coolant-side surface is dimensioned significantly smaller than the exhaust-side surface, which is why less comprehensive insulation is to be introduced.

The cylinder head with turbine according to the invention is particularly suitable for supercharged internal combustion engines, which are thermally particularly heavily loaded due to the higher exhaust gas temperatures. Cooling of the turbine of the exhaust gas turbocharger is therefore advantageous.

Also advantageous are embodiments in which the turbine is part of an exhaust gas turbocharger.

The charge is used primarily to increase the performance of the internal combustion engine. The air required for the combustion process is compressed, which allows each cylinder per working cycle, a larger air mass can be supplied. As a result, the fuel mass and thus the medium pressure can be increased.

The charge is a suitable means to increase the capacity of an internal combustion engine with unchanged displacement, or to reduce the displacement at the same power. In any case, the charge leads to an increase in engine capacity and a lower power mass. At the same vehicle boundary conditions, the load collective can thus be shifted to higher loads in which the specific fuel consumption is lower. Charging thus supports the constant effort in the development of internal combustion engines to minimize fuel consumption, d. H. to increase the efficiency.

Compared to a mechanical supercharger, the advantage of an exhaust-gas turbocharger is that there is no mechanical connection to the power transmission between the supercharger and the internal combustion engine or is required. While a mechanical supercharger obtains the energy required for its drive directly from the internal combustion engine, the exhaust gas turbocharger uses the exhaust gas energy of the hot exhaust gases.

If the cylinder head has a cylinder and this cylinder has only one outlet opening, the one cylinder-associated exhaust pipe forms the exhaust gas removal system, ie. H. the entire exhaust line or the manifold, which opens into the turbine. It is also a cylinder head according to the invention.

Embodiments in which the cylinder head has at least two cylinders are advantageous.

If the cylinder head has two cylinders and only the exhaust gas lines of one cylinder form an overall exhaust gas line which opens into the turbine, this is likewise a cylinder head according to the invention.

If the cylinder head has three or more cylinders and if only the exhaust gas lines of two cylinders are combined to form an overall exhaust gas line, this is likewise a cylinder head according to the invention.

Embodiments of the cylinder head, in which the cylinder head has, for example, four cylinders arranged in series and the exhaust pipes of the outer cylinders and the exhaust pipes of the inner cylinders merge to form an overall exhaust gas line, are likewise cylinder heads according to the invention.

• – mindestens drei Zylinder in der Art konfiguriert sind, dass sie zwei Gruppen mit jeweils mindestens einem Zylinder bilden, und
• – die Abgasleitungen der Zylinder jeder Zylindergruppe unter Ausbildung eines Abgaskrümmers jeweils zu einer Gesamtabgasleitung zusammenführen.

For three and more cylinders, therefore, embodiments are also advantageous in which

• - At least three cylinders are configured in such a way that they form two groups, each with at least one cylinder, and
• - Combine the exhaust gas lines of the cylinder of each cylinder group to form an exhaust manifold to form an overall exhaust gas line.

This embodiment is particularly suitable for the use of a twin-flow turbine. A double-flow turbine has an inlet region with two inlet channels, so to speak two inlet regions, wherein the two total exhaust gas lines are connected to the twin-flow turbine in such a way that in each case an entire exhaust gas line opens into an inlet channel. The merging of the two exhaust gas flows guided in the total exhaust gas lines is optionally carried out downstream of the turbine. If the exhaust pipes are grouped in such a way that the high pressures, in particular the Vorlassstöße, can be obtained, a double-flow turbine is particularly suitable for a burst charge, which also high turbine pressure ratios can be achieved at low speeds.

However, the grouping of the cylinders or exhaust pipes also offers advantages when using multiple turbines or exhaust gas turbocharger, wherein in each case an overall exhaust gas line is connected to a turbine.

But are also embodiments in which the exhaust pipes of all cylinders of the cylinder head to a single, d. H. merge together overall exhaust gas line.

Further advantageous embodiments of the cylinder head are discussed in connection with the subclaims.

Advantageous embodiments of the cylinder head, in which the at least one wall is provided to more than 50% with a thermal insulation.

Advantageous embodiments of the cylinder head, in which the at least one wall is provided to more than 70% with a thermal insulation.

Embodiments of the cylinder head in which the at least one wall is provided with heat insulation for more than 80% are advantageous.

Advantageous embodiments of the cylinder head, in which the at least one wall is completely provided with a thermal insulation.

Embodiments of the cylinder head in which the thermal insulation comprises enamel are advantageous.

Embodiments of the cylinder head in which the thermal insulation comprises ceramic are also advantageous.

Advantageous embodiments of the cylinder head, in which the heat insulation is at least formed by means of surface treatment. For the formation of the thermal insulation can also first material, such as enamel or ceramic or the like, are introduced and then surface-treated. Optionally, the thermal insulation is formed exclusively by means of surface treatment.

Embodiments of the cylinder head in which the turbine is a radial turbine are advantageous.

If the turbine is designed as a radial turbine, then the flow of the blades takes place substantially radially. In this case, essentially radial means that the velocity component in the radial direction is greater than the axial velocity component. The velocity vector of the flow intersects the shaft of the turbine at a right angle if the flow is exactly radial. In this respect, the turbine can also be designed in the mixed-flow design as long as the velocity component in the radial direction is greater than the velocity component in the axial direction.

In order to be able to flow radially to the rotor blades, the inlet region for supplying the exhaust gas is frequently designed as a spiral or worm casing extending all around, so that the inflow of the exhaust gas to the turbine takes place essentially radially.

Therefore, embodiments of the cylinder head in which the at least one coolant channel extends in the housing at least in sections spirally around the shaft are also advantageous.

Particularly advantageous in this context are embodiments of the cylinder head in which the at least one coolant channel extends circumferentially around and at a distance from the flow channel over an angle α with α ≦ 45 °.

Embodiments of the cylinder head are also advantageous, in which the following applies: α ≦ 30 ° or α ≦ 20 °. or α ≤ 15 °.

The smaller the angular range in which the coolant channel sweeps the flow channel in the circumferential direction, the less voluminous the housing must be carried out, d. H. the lower the material input, which is decisively influenced by the size of the coolant channel to be integrated. Consequently, the weight of the housing with the size of the coolant channel decreases or to.

With respect to the latter embodiments, reference is made to FIGS German patent application with the file number 10 2010 037 378.8 ,

Embodiments of the cylinder head in which the turbine has a single coolant channel integrated in the housing are advantageous for forming a cooling system.

Advantageous embodiments of the cylinder head, in which the turbine housing is a casting, in which the thermal insulation is introduced as part of a post-processing. In particular, coating and surface treatment are considered as post-processing.

Advantageous embodiments of the cylinder head, in which each cylinder has two outlet openings for discharging the exhaust gases from the cylinder.

It is the task of the valve train to open the inlet openings and outlet openings of the combustion chamber in time or close, with a quick release of the largest possible flow cross-sections is sought to the throttle losses in the einbzw. To keep outflowing gas flows low and the best possible filling of the combustion chamber with fresh mixture or an effective, d. H. To ensure complete removal of the exhaust gases. Therefore, it is advantageous to equip the cylinders with two or more outlet openings.

Embodiments of the cylinder head in which the exhaust pipes merge to form at least one exhaust gas manifold to form at least one overall exhaust gas line are advantageous, with these at least one exhaust gas line discharging into the inlet region of the turbine.

Particularly advantageous embodiments of the cylinder head, in which the exhaust pipes of the cylinder merge to form at least one integrated exhaust manifold within the cylinder head to at least one total exhaust line, said at least one total exhaust gas line opens into the inlet region of the turbine.

It should be noted that, in principle, the aim is to arrange the turbine, in particular the turbine of an exhaust gas turbocharger, as close as possible to the outlet of the cylinders in order to make optimum use of the exhaust gas enthalpy of the hot exhaust gases, which is largely determined by the exhaust gas pressure and the exhaust gas temperature and to ensure a fast response of the turbine or the turbocharger. Furthermore, the way the hot exhaust gases to the various exhaust aftertreatment systems should be as short as possible, so that the exhaust gases are given little time to cool and the exhaust aftertreatment systems reach their operating temperature or light-off as soon as possible, especially after a cold start of the engine.

Efforts are therefore made to minimize the thermal inertia of the section of the exhaust pipe between the outlet opening on the cylinder and the turbine or between the outlet opening on the cylinder and the exhaust aftertreatment system, which can be achieved by reducing the mass and the length of this section.

To achieve this goal, the exhaust pipes are merged to form at least one integrated exhaust manifold within the cylinder head.

The length of the exhaust pipes is thereby reduced. First, the line volume, i. H. the exhaust volume of the exhaust pipes upstream of the turbine, reduced, so that the response of the turbine is improved. On the other hand, the shortened exhaust pipes also lead to a lower thermal inertia of the exhaust system upstream of the turbine, so that the temperature of the exhaust gases at the turbine inlet increases, which is why the enthalpy of the exhaust gases at the entrance of the turbine is higher.

The merging of the exhaust pipes within the cylinder head also allows a dense packaging of the drive unit.

However, such a trained cylinder head is thermally more heavily loaded than a conventional cylinder head, which is equipped with an external manifold, and therefore makes increased demands on the cooling.

The heat released during combustion by the exothermic, chemical conversion of the fuel is partially dissipated via the walls delimiting the combustion chamber to the cylinder head and the cylinder block and partly via the exhaust gas flow to the adjacent components and the environment. In order to keep the thermal load of the cylinder head within limits, a part of the introduced into the cylinder head heat flow must be withdrawn from the cylinder head again.

Due to the high heat capacity of a liquid can be dissipated with a liquid cooling much larger amounts of heat than with air cooling, which is why cylinder heads of the type in question are advantageously equipped with a liquid cooling.

The liquid cooling requires the equipment of the cylinder head with at least one coolant jacket, d. H. the arrangement of the coolant through the cylinder head leading coolant channels. The heat is released inside the cylinder head to the coolant, which is conveyed by means of a pump arranged in the cooling circuit, so that it circulates in the coolant jacket. The heat given off to the coolant is removed in this way from the interior of the cylinder head and removed from the coolant in a heat exchanger again.

A liquid cooling proves to be particularly advantageous in turbocharged engines, since the thermal load of turbocharged engines compared to conventional internal combustion engines is significantly higher.

From the above it follows that embodiments of the cylinder head are advantageous in which the cylinder head is equipped to form a liquid cooling with at least one integrated in the cylinder head coolant jacket.

Embodiments of the cylinder head in which the at least one coolant jacket integrated in the cylinder head is connected to the at least one coolant channel of the turbine are advantageous.

If the at least one coolant jacket integrated in the cylinder head is connected to the at least one coolant channel of the turbine, the other components and units required for forming a cooling circuit must in principle only be provided in a single copy, since this applies both to the cooling circuit of the turbine and to that of the cylinder head can be used, which leads to synergies and significant cost savings, but also brings a weight savings. Thus, preferably only one pump for conveying the coolant and a container for Provision of the coolant provided. The heat emitted to the coolant in the cylinder head and in the turbine housing can be withdrawn from the coolant in a common heat exchanger.

In addition, the coolant channel of the turbine can be supplied via the cylinder head with coolant, so that no further Kühlmittelzuführ- and discharge openings must be provided on the turbine housing and can be dispensed with further coolant lines.

• – der Zylinderkopf an einer Montage-Stirnseite mit einem Zylinderblock verbindbar ist, und
• – der mindestens eine im Zylinderkopf integrierte Kühlmittelmantel einen unteren Kühlmittelmantel, der zwischen den Abgasleitungen und der Montage-Stirnseite des Zylinderkopfes angeordnet ist, und einen oberen Kühlmittelmantel, der auf der dem unteren Kühlmittelmantel gegenüberliegenden Seite der Abgasleitungen angeordnet ist, aufweist, wobei der obere Kühlmittelmantel und der untere Kühlmittelmantel vorzugsweise miteinander verbunden sind.

Advantageous are embodiments in which

• - The cylinder head is connected to a mounting end face with a cylinder block, and
• - The at least one integrated in the cylinder head coolant jacket has a lower coolant jacket, which is arranged between the exhaust pipes and the mounting end face of the cylinder head, and an upper coolant jacket, which is arranged on the opposite side of the lower coolant jacket exhaust pipes, wherein the upper coolant jacket and the lower coolant jacket are preferably connected together.

In this case, embodiments in which the lower coolant jacket and / or the upper coolant jacket are connected to the coolant jacket of the turbine are advantageous.

The cooling can additionally and advantageously be improved in that a pressure gradient is generated between the upper and lower coolant jacket, which leads to an increased heat transfer due to convection.

Such a pressure gradient also offers advantages if the lower coolant jacket and the upper coolant jacket are connected to one another with the coolant channel of the turbine or via the coolant jacket of the turbine. The pressure gradient then serves as a driving force for conveying the coolant through the coolant channel of the turbine.

Embodiments in which the turbine and the cylinder head constitute separate components which are connected to one another in a force-locking, positive-locking and / or material-locking manner are advantageous.

A modular construction, has the advantage that the individual components - namely the turbine or the cylinder head - can be combined according to the modular principle with other components, in particular other cylinder heads or turbines. The versatility of use of a component increases the number of units, whereby the manufacturing cost per piece can be reduced. In addition, this reduces the costs if the turbine or the cylinder head due to a defect exchange, d. H. to replace.

Also advantageous are embodiments in which the turbine housing is at least partially integrated in the cylinder head, so that the cylinder head and at least a part of the turbine housing form a monolithic component.

The formation of a gas-tight, thermally highly resilient and therefore costly connection between the cylinder head and turbine eliminates the principle by the one-piece design. As a result, there is also no danger that exhaust gas unintentionally leaks due to leakage into the environment. The same applies analogously to the coolant circuits or the connection of the coolant jackets and the leakage of coolant.

The turbine used can be equipped with a variable turbine geometry, which allows a further adaptation to the respective operating point of an internal combustion engine by adjusting the turbine geometry or the effective turbine cross section. In this case, guide vanes for influencing the flow direction are arranged in the inlet region of the turbine. Unlike the vanes of the rotating impeller, the vanes do not rotate with the shaft of the turbine.

If the turbine has a fixed invariable geometry, the vanes are not only stationary, but also completely immovable in the entry area, i. H. rigidly fixed. If, on the other hand, a turbine with variable geometry is used, the vanes are indeed arranged stationary, but not completely immobile, but rotatable about their axis, so that the flow of the blades can be influenced.

In the following the invention is based on an embodiment according to the 1 and 2 described in more detail. Hereby shows:

1 the turbine of a first embodiment in a section perpendicular to the shaft of the turbine runner, and

2 the in 1 marked section AA.

1 shows the turbine 1 a first embodiment in a section perpendicular to the shaft 7 of the turbine runner 6 ,

The turbine 1 is a radial turbine 1a which one in a turbine housing 3 arranged and on a rotatable shaft 7 stored impeller 6 includes. In order to be able to flow the blades radially, that is from the inlet area 4 outbound flow channel 5 spiral and the housing 3 designed to supply the exhaust gas as a completely extending spiral housing.

To form a cooling, the housing 3 an integrated coolant channel 8th on, in the housing 3 spiral around the shaft 7 extends and thus the flow channel 5 until the exhaust gas enters the impeller 6 follows. It can be seen that the coolant channel 8th spaced from the flow channel 5 runs on the impeller 6 opposite side of the flow channel 5 , Adjacent to the entrance area 4 of the turbine housing 3 are channel openings 9 provided to coolant in the coolant channel 8th initiate and pay off again. For fastening the turbine 1 on the cylinder head (not shown) is the housing 3 with a flange 10 fitted.

The the coolant channel 8th bounding walls 2 are with a thermal insulation 2a equipped, ie coated. By introducing this insulation 2a is the heat input from the housing 3 difficult in the coolant, causing both the housing 3 less heat is removed and less heat is introduced into the coolant. The cooling capacity is through the insulation 2a purposefully diminished by the heat permeability of the heat-transferring wall 2 is lowered.

2 shows the in 1 marked section AA. It should only be supplementary to 1 For that reason, reference is made to FIG 1 , The same reference numerals have been used for the same components.

The coolant channel 8th extends at the in 2 illustrated embodiment circumferentially about an angle α ≈ 90 ° to the flow channel 5 measured from the centerline of the flow channel 5 , Consequently, the coolant channel settles 8th in this case not similar to a coolant jacket - as large as possible around the flow channel 5 , In this way, the amount of heat absorbed by the coolant is also limited by reducing the heat transfer surfaces.

LIST OF REFERENCE NUMBERS

1

 turbine

1a

 radial turbine

2

 wall

2a

 thermal insulation

3

 turbine housing

4

 entry area

5

 flow channel

6

 Wheel

7

 wave

8th

 Coolant channel

9

 channel opening

10

 flange

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008011257 A1 [0012]
• EP 1384857 A2 [0013]
• DE 102007017973 A1 [0014]
• WO 2010/039590 A1 [0024]
• DE 102010037378 [0064]

Claims (17)

Cylinder head with cooled turbine ( 1 in which the cylinder head has at least one cylinder, each cylinder has at least one outlet opening for discharging the exhaust gases out of the cylinder and an exhaust pipe adjoins each outlet opening, the at least one exhaust pipe of at least one cylinder entering an inlet region. 4 ) of the turbine ( 1 ), the flow channel leading into an exhaust gas ( 5 ), and - the turbine ( 1 ), which at least one in a turbine housing ( 3 ) on a rotatable shaft ( 7 ) stored impeller ( 6 ) to form a cooling at least one in the housing ( 3 ) integrated coolant channel ( 8th ), which by at least one wall ( 2 ) is limited and formed, characterized in that - the at least one the at least one coolant channel ( 8th ) bounding wall ( 2 ) at least partially with a thermal insulation ( 2a ) is provided. Cylinder head with cooled turbine ( 1 ) according to claim 1, characterized in that the at least one wall ( 2 ) to more than 50% with a thermal insulation ( 2a ) is provided. Cylinder head with cooled turbine ( 1 ) according to claim 1 or 2, characterized in that the at least one wall ( 2 ) to more than 70% with a thermal insulation ( 2a ) is provided. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the at least one wall ( 2 ) to more than 80% with a thermal insulation ( 2a ) is provided. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the at least one wall ( 2 ) completely with a thermal insulation ( 2a ) is provided. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the thermal insulation ( 2a ) Enamel includes. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the thermal insulation ( 2a ) Ceramic. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the thermal insulation ( 2a ) is formed at least by means of surface treatment. Cylinder head with cooled turbine ( 1 ) According to one of the preceding claims, characterized in that the turbine ( 1 ) a radial turbine ( 1a ). Cylinder head with cooled turbine ( 1 ) according to claim 9, characterized in that the at least one coolant channel ( 8th ) in the housing ( 3 ) at least in sections spirally around the shaft ( 7 ). Cylinder head with cooled turbine ( 1 ) according to claim 9 or 10, characterized in that the at least one coolant channel ( 8th ) circumferentially about and spaced from the flow channel ( 5 ) extends through an angle α with α ≤ 45 °. Cylinder head with cooled turbine ( 1 ) according to claim 11, characterized in that: α ≤ 30 °. Cylinder head with cooled turbine ( 1 ) According to one of the preceding claims, characterized in that the turbine ( 1 ) to form a cooling in the housing ( 3 ) integrated coolant channel ( 8th ) having. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the turbine housing ( 3 ) is a casting into which the thermal insulation ( 2a ) is introduced as part of a post-processing. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that each cylinder has two outlet openings for discharging the exhaust gases from the cylinder. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the exhaust gas lines merge to form at least one exhaust gas manifold to form at least one overall exhaust gas line, wherein this at least one total exhaust gas line into the inlet area ( 4 ) of the turbine ( 1 ) opens. Cylinder head with cooled turbine ( 1 ) according to one of the preceding claims, characterized in that the exhaust gas lines of the cylinder merge to form at least one integrated exhaust manifold within the cylinder head to at least one total exhaust gas line , said at least one total exhaust gas line in the inlet region ( 4 ) of the turbine ( 1 ) opens.

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