DE102014218917A1 - Internal combustion engine with liquid cooled turbine and method for controlling the cooling of said turbine - Google Patents

Abstract

The invention relates to an internal combustion engine with liquid cooling (7), with at least one cylinder head (8) having at least two cylinders and at least one liquid-cooled turbine (1), in which - each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder and connected to each outlet opening an exhaust pipe, wherein the exhaust pipes merge to form at least one exhaust manifold to at least one total exhaust pipe, which in the at least one turbine housing (1 a) having turbine (1) opens, - the at least one turbine (1) for forming a cooling at least one in the housing (1a) integrated coolant jacket (2), wherein the at least one coolant jacket (2) with the liquid cooling (7) is at least connectable, and - a vent line (3) is provided, of the at least one coolant jacket (2 ) at a geodetically highest n branch off and opens into a venting container. An internal combustion engine is to be provided which is optimized with regard to cooling. This object is achieved by an internal combustion engine, which is characterized in that - a bypass line (4) branches off to form a first node (5) of the vent line (3), wherein a shut-off device (6) is provided which either the vent line ( 3) or the bypass line (4) releases.

Description

• – jeder Zylinder mindestens eine Auslassöffnung zum Abführen der Abgase aus dem Zylinder aufweist und sich an jede Auslassöffnung eine Abgasleitung anschließt, wobei die Abgasleitungen unter Ausbildung mindestens eines Abgaskrümmers zu mindestens einer Gesamtabgasleitung zusammenführen, welche in die mindestens eine ein Turbinengehäuse aufweisende Turbine mündet,
• – die mindestens eine Turbine zur Ausbildung einer Kühlung mindestens einen im Gehäuse integrierten Kühlmittelmantel aufweist, wobei der mindestens eine Kühlmittelmantel mit der Flüssigkeitskühlung zumindest verbindbar ist, und
• – eine Entlüftungsleitung vorgesehen ist, die von dem mindestens einen Kühlmittelmantel an einer geodätisch am höchsten gelegenen Stelle abzweigt und in ein Entlüftungsbehältnis mündet.

The invention relates to an internal combustion engine with liquid cooling, with at least one cylinder head with at least two cylinders and with at least one liquid-cooled turbine, in which

• 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, wherein the exhaust pipes merge to form at least one exhaust gas line to form at least one exhaust gas line which opens into the at least one turbine housing having a turbine housing,
• - The at least one turbine for forming a cooling at least one integrated in the housing coolant jacket, wherein the at least one coolant jacket with the liquid cooling is at least connectable, and
• - A vent line is provided, which branches off from the at least one coolant jacket at a geodetically highest point and opens into a venting container.

Furthermore, the invention relates to a method for controlling the cooling of the at least one liquid-cooled turbine of an internal combustion engine of the above type.

An internal combustion engine of the type mentioned is used as a motor vehicle drive. In the context of the present invention, the term internal combustion engine includes diesel engines and gasoline engines, but also hybrid internal combustion engines that use a hybrid combustion process, as well as hybrid drives, which in addition to the internal combustion engine include an electric motor that can be connected to the engine, which receives power from the internal combustion engine or as switchable auxiliary drive additionally delivers power.

Internal combustion engines have a cylinder block and at least one cylinder head, which is used to form the at least two cylinders, d. H. Combustion chambers 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 fresh air, via the inlet openings. To control the charge cycle, four-stroke engines use almost exclusively lift 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 combination of exhaust pipes to an overall exhaust line is generally and also referred to in the context of the present invention as exhaust manifold.

Downstream of the at least one exhaust manifold, the exhaust gases are then fed to at least one 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 can be comparatively high, since the material which is frequently used for the thermally highly stressed turbine housing-nickel-containing material-is expensive, in particular in comparison with the material preferably used for the cylinder head; for example aluminum. Not only the costs for the nickel-containing materials per se, but also the costs for processing these materials are comparatively high.

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, especially considering that a close-coupled arrangement of the turbine often leads to a relatively large-sized, voluminous housing, since the connection of turbine and cylinder head by means of flange and screws due to the cramped space requires a large turbine inlet area; also because there is enough space for the assembly tools must be provided. 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 material.

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. The coolant used is usually a mixed with additives water-glycol mixture. Water has the advantage over other refrigerants that it is non-toxic, readily available and inexpensive and also has a very high heat capacity, which is why water is suitable for the removal and removal of very large amounts of heat, which is generally considered to be advantageous.

In general, the turbine housing is provided to form the 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.

If the turbine is subjected to particularly high thermal loads, for example due to the very hot exhaust gas flow at high loads or full load, gas bubbles may form in the coolant jacket, which is why a vent line is provided in the internal combustion engine which is the subject of the present invention, of the at least one Coolant jacket branches off at a geodetically highest point and opens into a venting container. By means of vent line, the gas bubbles can be removed from the coolant jacket of the turbine, so that damage to the housing and thermal overload can be avoided and effective cooling can be ensured.

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. The latter requires only appropriate connections of both circuits.

It is not the aim and the object of a liquid cooling, the internal combustion engine or the turbine housing under all operating conditions to extract the largest possible amount of heat. Rather, a needs-based control of the liquid cooling is desired. Thus, in the context of demand-based control of the turbine cooling in the warm-up phase, in particular after a cold start of the internal combustion engine, the lowest possible, preferably no heat extraction would be sought so that the hot exhaust gas heats up the downstream exhaust aftertreatment systems as quickly as possible.

In order to reduce the friction loss and thus the fuel consumption of an internal combustion engine, rapid heating of the engine oil, in particular after a cold start, can be expedient. Rapid heating of the engine oil during the warm-up phase of the engine provides for a correspondingly rapid decrease in the viscosity of the oil and thus for a reduction of friction or friction, especially in the oil-bearing, for example, the bearings of the crankshaft.

Numerous concepts are known from the prior art, with which the friction loss can be reduced by rapid heating of the engine oil. The oil can be actively heated, for example by means of external heating device. According to another concept, a coolant-operated oil cooler is used in the warm-up phase and used for heating the oil, which in turn requires rapid heating of the coolant.

In principle, rapid heating of the engine oil to reduce friction losses can also be achieved by rapid heating of the internal combustion engine itself, which in turn is assisted by d. H. forced, is that the internal combustion engine during the warm-up phase as little heat is removed.

In this respect, the warm-up phase of the internal combustion engine after a cold start is an example of an operating mode in which it is advantageous to extract the internal combustion engine as little as possible, preferably no heat.

So-called no-flow strategies are known from the prior art, in which the coolant flow through the cylinder head or the cylinder block of a liquid-cooled internal combustion engine is completely prevented in order to extract as little heat as possible from the internal combustion engine.

For reasons of comfort, however, it may be advantageous or desirable, in particular after a cold start, to supply a coolant-driven vehicle interior heating via a heating circuit line with coolant preheated in the cylinder head and / or cylinder block. This creates a conflict of objectives, namely on the one hand preheat coolant in the cylinder head or cylinder block to provide the heater preheated coolant available, and on the other hand to suppress or reduce the coolant flow through the cylinder head or cylinder block to the internal combustion engine during the warm-up phase as little as possible To remove heat.

In view of the above, it is an object of the present invention to provide an internal combustion engine according to the preamble of claim 1, which is optimized in terms of cooling.

Another object of the present invention is to provide a method for controlling the cooling of the at least one liquid-cooled turbine.

• – jeder Zylinder mindestens eine Auslassöffnung zum Abführen der Abgase aus dem Zylinder aufweist und sich an jede Auslassöffnung eine Abgasleitung anschließt, wobei die Abgasleitungen unter Ausbildung mindestens eines Abgaskrümmers zu mindestens einer Gesamtabgasleitung zusammenführen, welche in die mindestens eine ein Turbinengehäuse aufweisende Turbine mündet,
• – die mindestens eine Turbine zur Ausbildung einer Kühlung mindestens einen im Gehäuse integrierten Kühlmittelmantel aufweist, wobei der mindestens eine Kühlmittelmantel mit der Flüssigkeitskühlung zumindest verbindbar ist, und
• – eine Entlüftungsleitung vorgesehen ist, die von dem mindestens einen Kühlmittelmantel an einer geodätisch am höchsten gelegenen Stelle abzweigt und in ein Entlüftungsbehältnis mündet, und die dadurch gekennzeichnet ist, dass
• – eine Bypassleitung unter Ausbildung eines ersten Knotenpunktes von der Entlüftungsleitung abzweigt, wobei eine Absperrvorrichtung vorgesehen ist, welche entweder die Entlüftungsleitung oder die Bypassleitung freigibt.

The first sub-task is solved by an internal combustion engine with liquid cooling, with at least one cylinder head with at least two cylinders and with at least one liquid-cooled turbine in which

• 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, wherein the exhaust pipes merge to form at least one exhaust gas line to form at least one exhaust gas line which opens into the at least one turbine housing having a turbine housing,
• - The at least one turbine for forming a cooling at least one integrated in the housing coolant jacket, wherein the at least one coolant jacket with the liquid cooling is at least connectable, and
• A vent line is provided, which branches off from the at least one coolant jacket at a geodetically highest point and opens into a venting container, and which is characterized in that
• - A bypass line branches off to form a first node of the vent line, wherein a shut-off device is provided which releases either the vent line or the bypass line.

The internal combustion engine according to the invention utilizes the fact that gas bubbles only form in the coolant jacket of the turbine when the turbine housing is subject to particularly high thermal loads. The intended vent line is therefore not non-stop, d. H. not permanently used for removing gas bubbles. This circumstance opens up the possibility of removing heated coolant from the at least one coolant jacket of the turbine via a vent line in the turbine housing and feeding it to a suitable location. H. to provide a consumer who has a need for heated coolant.

According to the invention this is realized by providing a bypass line which branches off from the vent line to form a first node. A shut-off device controls the lines in such a way that the vent line and / or the bypass line is released or blocked.

Especially the turbine is suitable for the provision of heated coolant due to the high thermal load. It should also be considered in this context that turbine housings of modern turbines are often no longer equipped with a coolant jacket in the conventional sense, which completely envelopes or surrounds the at least one impeller of the turbine, because the amount of heat to be absorbed by the coolant can amount to 40kW or more, and the removal of such high amounts of heat as has proved problematic. Rather, a minimalist cooling of the turbine housing is regularly preferred in which at least one comparatively small dimensioned coolant channel in the housing - preferably annularly around the shaft - extends. The cooling capacity is deliberately limited by the at least one coolant channel and with this the heat-transferring surface are dimensioned smaller than usual.

Such a coolant channel covers or covers in a section along the shaft an exhaust gas leading flow channel of the turbine only in a limited angle range α, for example, with α ≤ 45 °, α ≤ 35 ° or α ≤ 25 °, and no longer as coat-like possible a large area. The coolant channel can have maximum diameters of less than 12 or 8 millimeters.

As a matter of principle, such a small-sized coolant channel leads to high flow velocities and thus to a high heat transfer due to convection, in particular even with small coolant flow rates.

The latter proves to be particularly advantageous after a cold start of the internal combustion engine when the coolant flow through the cylinder head or the cylinder block of a liquid-cooled internal combustion engine is to be minimized in order to extract as little heat as possible from the internal combustion engine, but at the same time there is a need for heated coolant, for example in the coolant-driven Vehicle interior heating of a motor vehicle or a coolant-operated oil cooler for heating the engine oil. The coolant passed through the coolant jacket does not necessarily have to be taken from the cylinder head or the cylinder block of the liquid-cooled internal combustion engine. Rather, bypassing the cylinder head or the cylinder block, a coolant circuit can be formed, in which, in addition to the at least one coolant jacket of the turbine housing, at least one consumer is arranged, which has a need for heated coolant.

Thus, the first sub-problem underlying the invention is solved, namely an internal combustion engine according to the preamble of claim 1 is provided, which is optimized in terms of cooling.

The at least one turbine can be designed as a radial turbine, d. H. 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 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.

However, the at least one turbine can also be designed as an axial turbine, in which the velocity component in the axial direction is greater than the velocity component in the radial direction.

Embodiments of the internal combustion engine which are equipped with a charge, preferably an exhaust gas turbocharger, are advantageous. A supercharged internal combustion engine is thermally particularly heavily loaded due to the higher exhaust gas temperatures, which is why a cooling of the turbine of the at least one exhaust gas turbocharger is advantageous.

In this context, embodiments in which the at least one liquid-cooled turbine is part of an exhaust-gas turbocharger are advantageous.

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 charging leads to an increase in space performance and a lower power mass. Under the same vehicle boundary conditions, the load spectrum can thus be shifted to higher loads, where the specific fuel consumption is lower. Charging therefore supports the constant effort in the development of internal combustion engines to minimize fuel consumption, d. H. to improve the efficiency of the internal combustion engine.

Compared to a mechanical supercharger, the advantage of an exhaust gas turbocharger is that no mechanical connection is required for transmitting power between the supercharger and the internal combustion engine. 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 two cylinders and only the exhaust gas lines of one cylinder form an overall exhaust gas line which opens into the at least one turbine, this is likewise an internal combustion engine according to the invention.

If the cylinder head has three or more cylinders and combine only the exhaust gas lines of two cylinders to form an overall exhaust gas line, this is likewise an internal combustion engine according to the invention.

Embodiments in which the at least one cylinder head has, for example, four cylinders arranged in series and in each case bring together the exhaust pipes of the outer cylinders and the exhaust pipes of the inner cylinders to form an overall exhaust gas line are also internal combustion engines 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, 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 at least one cylinder head to a single, d. H. merge together overall exhaust gas line.

Further advantageous embodiments of the internal combustion engine are discussed in connection with the subclaims.

Embodiments of the internal combustion engine in which the bypass line is at least connectable to a coolant-operated oil cooler are advantageous. As already mentioned, the frictional loss of an internal combustion engine can be reduced by rapid or accelerated heating of the engine oil. During the warm-up phase, a coolant-operated oil cooler is suitable for heating the oil, for which in the present case preheated coolant is used in the turbine housing, which is supplied to the oil cooler via bypass line.

Advantageous embodiments of the internal combustion engine, in which the bypass line with a coolant-driven heater is at least connectable. In particular, after a cold start, there is often a need for heating the vehicle interior. A coolant-operated heater can be supplied via bypass line with preheated in the turbine housing coolant.

Advantageous embodiments of the internal combustion engine, in which a return line branches off from the vent line, wherein the return line with the liquid cooling is at least connectable.

The at least one coolant jacket provided in the turbine housing can be connected via return line, for example, to the liquid-cooled cylinder head or the liquid-cooled cylinder block of the internal combustion engine, which, like the coolant-operated oil cooler and the coolant-operated heater, also represent consumers who have a need for heated coolant in the warm-up phase ,

The coolant heated in the turbine housing serves to accelerate the heating of the internal combustion engine, ensures a correspondingly rapid decrease in the viscosity of the oil and thus a reduction in the friction or friction power.

Embodiments of the internal combustion engine in which a shut-off element is arranged in the return line are advantageous. In the present case, a single shut-off element is arranged in the return line, which only serves to control the return line, i. H. the release and blocking of the return line.

Embodiments of the internal combustion engine in which the return line branches off from the vent line at the first node are also advantageous in this context, with the shut-off device at the first node is arranged and the return line either free or blocked.

The branching of the return line at the first node allows the control of both the return line and the bypass line with only a single shut-off, such as a 3-2-way valve.

Therefore, embodiments of the internal combustion engine in which the shut-off device is a 3-2-way valve arranged at the first junction, which is connected to the vent line, the bypass line and the return line, are also advantageous.

But can also be advantageous embodiments of the internal combustion engine, in which in each case a shut-off element is arranged in the bypass line and in the vent line.

Embodiments of the internal combustion engine in which the venting container is geodetically higher than the at least one coolant jacket are advantageous. This advantageously supports the removal of gas and vapor bubbles via the vent line and ensures optimized venting. In this case, the effect is exploited that the buoyancy forces acting on the gas bubbles drive the gases contained in the coolant jacket through the vent line.

The buoyancy forces are also the reason why the vent line branches off at the geodetically highest point of the coolant jacket where the bubbles collect.

As far as in the present invention of a geodetic height difference or a geodetic height is mentioned, reference is made to the installation position of the internal combustion engine together with its components and a horizontally stationary vehicle.

Embodiments of the internal combustion engine in which the at least one coolant jacket is at least connectable to the liquid cooling of the internal combustion engine via at least one feed opening are advantageous.

Also advantageous are embodiments of the internal combustion engine, in which the at least one coolant jacket via at least one discharge opening with the liquid cooling of the internal combustion engine is at least connectable.

If the at least one coolant jacket is connected or connectable to the liquid cooling of the internal combustion engine, the other components and units required for forming a cooling circuit must in principle only be provided in a single copy, since these are used both for the cooling circuit of the at least one turbine and for that of the internal combustion engine can be used, which leads to synergies and cost savings, but also brings a weight saving. The heat delivered to the coolant in the internal combustion engine and in the turbine housing can be withdrawn from the coolant in a common heat exchanger.

In this context, embodiments of the internal combustion engine in which a shut-off element is provided on the inlet side, which opens or blocks the feed opening, and on the outlet side a shut-off element is provided which releases or obstructs the discharge opening.

Embodiments of the internal combustion engine in which the turbine housing is an integrally cast component are advantageous. By casting and using appropriate cores, the complex structure of the housing can be formed in one operation, so that subsequently only a post-processing of the housing and the assembly are required to form the turbine. Leakage is guaranteed.

Embodiments of the internal combustion engine in which the turbine housing of the at least one turbine is modularly constructed from at least two components are also advantageous, wherein each of the at least two components comprises a casting, ie. H. may be a component produced by casting.

Advantageous embodiments of the internal combustion engine, in which each cylinder has at least two outlet openings for discharging the exhaust gases from the cylinder.

It is the task of the valve drive to release the exhaust ports of the combustion chamber in time or to close, with a quick release of the largest possible flow cross sections is sought to keep the throttle losses in the outflowing exhaust gases low and 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 internal combustion engine in which the exhaust pipes merge within the at least one cylinder head to form at least one overall exhaust gas line, forming at least one integrated exhaust manifold, are advantageous.

It should be noted that, in principle, the aim is for the turbine, in particular the turbine of an exhaust-gas turbocharger, to be as close as possible to the turbine To arrange outlet of the cylinder, in order to be able to optimally use the exhaust enthalpy of the hot exhaust gases, which is largely determined by the exhaust pressure and the exhaust gas temperature, and to ensure a fast response of the turbine or the turbocharger. Furthermore, the path of 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 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, reduces the number of components and facilitates assembly.

However, a cylinder head with integrated exhaust manifold is thermally loaded higher than a conventional cylinder head, which is equipped with an external manifold, and therefore makes increased demands on the cooling.

Therefore, embodiments of the internal combustion engine in which the at least one cylinder head is equipped to form a liquid cooling with at least one coolant jacket integrated in the cylinder head are also advantageous.

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. The coolant 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.

Merging the exhaust pipes within the cylinder head, d. H. the integration of the at least one exhaust manifold, together with the equipment of the head with a liquid cooling during cold start of the engine to a rapid heating of the coolant, thus to a faster heating of the internal combustion engine and, if a coolant-driven heating of the passenger compartment of a vehicle is provided to a faster heating of this passenger compartment.

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. The integration of the at least one exhaust manifold in the liquid-cooled cylinder head makes a made of thermally highly resilient material external manifold possibly unnecessary, which has cost advantages.

Embodiments of the internal combustion engine in which the at least one cylinder head is equipped to form a liquid cooling system with at least one coolant jacket integrated in the cylinder head are advantageous.

• – 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, umfasst.

Embodiments of the internal combustion engine in which the at least one cylinder head can be connected to a cylinder block at a mounting end face are advantageous, and

• - The at least one integrated in the cylinder head coolant jacket comprises 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.

In this connection, embodiments of the internal combustion engine in which the upper coolant jacket with a feed opening of the at least one coolant jacket of the turbine and the lower coolant jacket with a discharge opening of the at least one coolant jacket of the turbine are at least connectable are advantageous.

Embodiments of the internal combustion engine in which the upper coolant jacket can be connected to a discharge opening of the at least one coolant jacket of the turbine and the lower coolant jacket to a supply opening of the at least one coolant jacket of the turbine can also be advantageous in this context.

Between the upper and lower coolant jacket, a pressure gradient can be generated. The pressure gradient then serves as a driving force for conveying the coolant through the at least one coolant jacket of the turbine.

Embodiments of the internal combustion engine may also be advantageous in which the upper coolant jacket with a first supply opening of the at least one coolant jacket of the turbine and the lower coolant jacket with a second supply opening of the at least one coolant jacket of the turbine is at least connectable.

The turbine 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, adjustable 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. With a variable geometry, however, the vanes are indeed arranged stationary, but not completely immobile, but rotatable about its axis, so that the flow of the blades can be influenced.

In the structural design of the cooled turbine, a compromise between cooling capacity and material is required, which is basically aimed at cooling the turbine only to the extent that actually requires the material used to in this way the exhaust gas enthalpy of the hot exhaust gases, which significantly from the exhaust gas temperature is determined to be able to use optimally. Corresponding to the moderate cooling performance of a minimalist cooling is to choose a corresponding material for the production of the turbine, namely gray cast iron or steel casting or the like.

The second sub-task on which the invention is based, namely to disclose a method for controlling the cooling of the at least one liquid-cooled turbine of an internal combustion engine of a type described above, is achieved by a method in which the bypass line is released in the warm-up phase of the internal combustion engine and the vent line is obstructed.

The comments made in connection with the internal combustion engine according to the invention also apply to the inventive method.

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

1 schematically the coolant jacket of the liquid-cooled turbine of a first embodiment of the internal combustion engine, cut perpendicular to the turbine shaft.

1 shows schematically the coolant jacket 2 the liquid-cooled turbine 1 a first embodiment of the internal combustion engine, perpendicular to the turbine shaft 1b cut.

The turbine 1 Exhaust gas is supplied to an internal combustion engine. The a turbine housing 1a having turbine 1 has the exhaust through the turbine 1 leading flow channel in the housing 1a is implemented, and one in the housing 1a arranged and on the rotatable turbine shaft 1b stored impeller (not shown).

To form a liquid cooling is the turbine 1 with a coolant jacket 2 equipped in the housing 1a integrated and via feed openings 2a . 2 B with the engine cooling 7 the internal combustion engine is connected. In the present case, the coolant jacket 2 the turbine 1 via cylinder head 8th supplied with coolant. The liquid-cooled cylinder head 8th is connectable to a cylinder block at a mounting end face and has a lower coolant jacket 8b that is between the exhaust pipes and the mounting end of the cylinder head 8th is arranged, and an upper coolant jacket 8a Standing on the lower coolant jacket 8b opposite side of the exhaust pipes is arranged. The upper coolant jacket 8a communicates via connection channel 8c with the lower coolant jacket 8b and vice versa.

In the present case, the upper coolant jacket 8a with a first feed opening 2a of the coolant jacket 2 the turbine 1 and the lower coolant jacket 8b with a second feed opening 2 B of the coolant jacket 2 the turbine 1 at least connectable.

A vent line 3 branches at the geodesic highest point of the coolant jacket 2 the turbine 2 from and empties into a venting container (not shown). A bypass line 4 branches under training of a first junction 5 from the vent line 3 from, with a shut-off device 6 at the first node 5 is arranged, which either the vent line 3 or the bypass line 4 releases.

LIST OF REFERENCE NUMBERS

1

 liquid cooled turbine

1a

 turbine housing

1b

 turbine shaft

2

 Coolant jacket of the turbine housing

2a

 first feed opening

2 B

 second feed opening

3

 vent line

4

 bypass line

5

 first node

6

 Shut-off

7

 Engine cooling, liquid cooling of the internal combustion engine

8th

 liquid cooled cylinder head

8a

 Upper coolant jacket

8b

 lower coolant jacket

8c

 connecting channel

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 [0014]
• EP 1384857 A2 [0015]
• DE 102007017973 A1 [0016]

Claims (18)

Internal combustion engine with liquid cooling ( 7 ), with at least one cylinder head ( 8th ) with at least two cylinders and at least one liquid-cooled turbine ( 1 ), in which - each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder and an exhaust pipe connects to each outlet opening, wherein the exhaust pipes merge to form at least one exhaust manifold to at least one exhaust line which into the at least one turbine housing ( 1a ) having turbine ( 1 ), - the at least one turbine ( 1 ) for forming a cooling at least one in the housing ( 1a ) integrated coolant jacket ( 2 ), wherein the at least one coolant jacket ( 2 ) with the liquid cooling ( 7 ) is at least connectable, and - a vent line ( 3 ) provided by the at least one coolant jacket ( 2 ) branches off at a geodetically highest point and opens into a venting container, characterized in that - a bypass line ( 4 ) forming a first node ( 5 ) from the vent line ( 3 ), wherein a shut-off device ( 6 ) is provided, which either the vent line ( 3 ) or the bypass line ( 4 ) releases. Internal combustion engine according to claim 1, characterized in that the bypass line ( 4 ) Is at least connectable with an oil cooler. Internal combustion engine according to claim 1 or 2, characterized in that the bypass line ( 4 ) Is at least connectable with a heater. Internal combustion engine according to one of the preceding claims, characterized in that a return line from the vent line ( 3 ), wherein the return line with the liquid cooling ( 7 ) is at least connectable. Internal combustion engine according to claim 4, characterized in that a shut-off element is arranged in the return line. Internal combustion engine according to claim 4, characterized in that the return line at the first node ( 5 ) from the vent line ( 3 ), wherein the shut-off device ( 6 ) at the first node ( 5 ) is arranged and the return line either free or blocked. Internal combustion engine according to claim 6, characterized in that the shut-off device ( 6 ) at the first node ( 5 ) arranged 3-2-way valve, which with the vent line ( 3 ), the bypass line ( 4 ) and the return line is connected. Internal combustion engine according to one of claims 1 to 5, characterized in that in the bypass line ( 4 ) and in the vent line ( 3 ) is arranged in each case a shut-off. Internal combustion engine according to one of the preceding claims, characterized in that the venting container is geodetically higher than the at least one coolant jacket ( 2 ). Internal combustion engine according to one of the preceding claims, characterized in that the at least one coolant jacket ( 2 ) via at least one feed opening ( 2a . 2 B ) with the liquid cooling ( 7 ) of the internal combustion engine is at least connectable. Internal combustion engine according to one of the preceding claims, characterized in that the at least one coolant jacket ( 2 ) via at least one discharge opening with the liquid cooling ( 7 ) of the internal combustion engine is at least connectable. Internal combustion engine according to one of the preceding claims, characterized in that the exhaust gas lines forming at least one integrated exhaust manifold within the at least one cylinder head ( 8th ) merge to at least one total exhaust line. Internal combustion engine according to one of the preceding claims, characterized in that the at least one cylinder head ( 8th ) for forming a liquid cooling ( 7 ) with at least one in the cylinder head ( 8th ) integrated coolant jacket ( 8a . 8b ) Is provided. Internal combustion engine according to claim 13, characterized in that - the at least one cylinder head ( 8th ) is connectable to a cylinder block at a mounting end face, and - the at least one in the cylinder head ( 8th ) integrated coolant jacket ( 8a . 8b ) a lower coolant jacket ( 8b ), which between the exhaust pipes and the mounting end face of the cylinder head ( 8th ), and an upper coolant jacket ( 8a ) located on the lower coolant jacket ( 8b ) opposite side of the exhaust pipes is arranged comprises. Internal combustion engine according to claim 14, characterized in that the upper coolant jacket ( 8a ) with a feed opening ( 2a . 2 B ) of the at least one coolant jacket ( 2 ) of the turbine ( 1 ) and the lower coolant jacket ( 8b ) with a Discharge opening of the at least one coolant jacket ( 2 ) of the turbine ( 1 ) is at least connectable. Internal combustion engine according to claim 14, characterized in that the upper coolant jacket ( 8a ) with a discharge opening of the at least one coolant jacket ( 2 ) of the turbine ( 1 ) and the lower coolant jacket ( 8b ) with a feed opening ( 2a . 2 B ) of the at least one coolant jacket ( 2 ) of the turbine ( 1 ) is at least connectable. Internal combustion engine according to claim 14, characterized in that the upper coolant jacket ( 8a ) with a first feed opening ( 2a ) of the at least one coolant jacket ( 2 ) of the turbine ( 1 ) and the lower coolant jacket ( 8b ) with a second feed opening ( 2 B ) of the at least one coolant jacket ( 2 ) of the turbine ( 1 ) is at least connectable. Method for controlling the cooling of the at least one liquid-cooled turbine ( 1 ) an internal combustion engine according to one of the preceding claims, characterized in that in the warm-up phase of the internal combustion engine, the bypass line ( 4 ) and the vent line ( 3 ) is blocked.

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