DE102014220570A1 - Charged internal combustion engine with double-flow turbine and grouped cylinders - Google Patents

Abstract

Internal combustion engine with min. a cylinder head with min. two cylinders, in which - each cylinder min. has an outlet opening, which is followed by an exhaust pipe, - min. two cylinders are configured in such a way that these two groups each with min. form a cylinder, - merge the exhaust gas lines of the cylinders of each cylinder group with the formation of an exhaust manifold to form an overall exhaust gas line, - min. an exhaust gas turbocharger is provided, which comprises a double-flow turbine (1), and - the two total exhaust gas lines with the twin-flow turbine (1), in the manner in an inlet region (2a) of the turbine housing (2) are connected, in each case an overall exhaust gas line with a the two floods (5, 6) of the turbine (1) is connected, wherein the two floods (5, 6) - in continuation of the total exhaust gas lines - up to the min. an impeller (3) by means of min. a housing wall (2c) are separated from each other and thus also the Abgasabführsysteme the cylinder groups, wherein - the turbine (1) is a double-flow axial turbine (1), and - the inlet region (2a) of the turbine housing (2) coaxial with the shaft (4) Axial turbine (1) extends and is formed so that the inflow of the exhaust gas in the inlet region (2a) of the turbine (1) takes place substantially axially, and - the min. a housing wall (2c) is at least partially helically formed on the impeller side.

Description

• – jeder Zylinder mindestens eine Auslassöffnung zum Abführen der Abgase aus dem Zylinder via Abgasabführsystem aufweist und sich an jede Auslassöffnung eine Abgasleitung anschließt,
• – mindestens zwei Zylinder in der Art konfiguriert sind, dass diese zwei Gruppen mit jeweils mindestens einem Zylinder bilden,
• – die Abgasleitungen der Zylinder jeder Zylindergruppe unter Ausbildung eines Abgaskrümmers jeweils zu einer Gesamtabgasleitung zusammenführen,
• – mindestens ein Abgasturbolader vorgesehen ist, der eine im Abgasabführsystem angeordnete zweiflutige Turbine umfasst, und
• – die beiden Gesamtabgasleitungen mit der zweiflutigen Turbine, die mindestens ein in einem Turbinengehäuse auf einer drehbaren Welle gelagertes und mit Laufschaufeln ausgestattetes Laufrad umfasst, in der Art in einem Eintrittsbereichs des Turbinengehäuses verbunden sind, dass jeweils eine Gesamtabgasleitung mit einer der zwei Fluten der Turbine verbunden ist, wobei die zwei Fluten – in Fortsetzung der Gesamtabgasleitungen – bis hin zu dem mindestens einen Laufrad mittels mindestens einer Gehäusewandung voneinander getrennt sind und damit auch die Abgasabführsysteme der Zylindergruppen.

The invention relates to a supercharged internal combustion engine having at least one cylinder head with at least two cylinders, in which

• Each cylinder has at least one outlet opening for discharging the exhaust gases out of the cylinder via the exhaust gas removal system and an exhaust gas line adjoins each outlet opening,
• At least two cylinders are configured in such a way that they form two groups each having at least one cylinder,
• - Combine the exhaust gas lines of the cylinders of each cylinder group to form an exhaust gas manifold, respectively to form an exhaust gas line,
• - At least one exhaust gas turbocharger is provided which comprises a arranged in Abgasabführsystem double-flow turbine, and
• - The two total exhaust gas lines with the twin-bladed turbine, which comprises at least one mounted in a turbine housing on a rotatable shaft and equipped with blades impeller are connected in the manner in an inlet region of the turbine housing, that in each case an overall exhaust gas line connected to one of the two floods of the turbine is, wherein the two floods - in continuation of the total exhaust pipes - up to the at least one impeller by means of at least one housing wall are separated from each other and thus also the Abgasabführsysteme the cylinder groups.

An internal combustion engine of the above type is used as a motor vehicle drive. In the context of the present invention, the term internal combustion engine includes gasoline engines, diesel 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 comprise an electric motor which can be connected to the internal combustion 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 are connected to one another to form the present at least two cylinders. The cylinder head is usually used to hold the valve train. In order to control the charge cycle, an internal combustion engine requires controls - usually in the form of valves - and actuators to operate these controls. The required for the movement of the valves valve actuating mechanism including the valves themselves is referred to as a valve train. As part of the change of charge, the combustion gases are pushed out via the outlet openings of the at least two cylinders and the cylinders are filled with fresh mixture or charge air via the inlet openings.

The exhaust pipes, which connect to the outlet openings, are at least partially integrated in the cylinder head according to the prior art and are combined to form a common overall exhaust gas line or in groups to two or more total exhaust gas lines. Merging exhaust pipes to an overall exhaust line is referred to generally and in the context of the present invention as an exhaust manifold.

In what way the exhaust pipes of the cylinders are merged in an individual case, d. H. the specific configuration of the exhaust pipe system depends essentially on the operating ranges of the internal combustion engine to be optimized with regard to which operating ranges.

In supercharged internal combustion engines in which at least one turbine of an exhaust gas turbocharger is provided in the Abgasabführsystem and in the lower speed or load range, d. H. For smaller quantities of exhaust gas, to have a satisfactory performance, a so-called shock charging is sought, d. H. prefers.

The purpose is to use the dynamic wave processes which take place in the exhaust gas removal system, in particular during the charge exchange, for the purpose of charging and for improving the operating behavior of the internal combustion engine.

The evacuation of the combustion gases from a cylinder of the internal combustion engine in the context of the charge exchange is based essentially on two different mechanisms. At the beginning of the charge cycle, when the exhaust valve opens near bottom dead center, the combustion gases flow at high speed through the exhaust port into the exhaust gas discharge system due to the high pressure level prevailing in the cylinder at the end of combustion and the associated high pressure difference between the combustion chamber and the exhaust pipe. This pressure-driven flow process is accompanied by a high pressure peak, which is also referred to as Vorlassstoß and propagates along the exhaust pipe at the speed of sound, whereby the pressure degrades more or less with increasing distance due to friction, d. H. reduced.

In the course of the charge cycle, the pressures in the cylinder and in the exhaust line are the same, so that the combustion gases are primarily no longer pressure-driven evacuated, but are ejected as a result of the stroke of the piston.

At low speeds, the pre-discharge pulse can advantageously be used for boost charging, wherein short time, high pressure pulses are used as best as possible for energy use in the turbine. In this way, by means of turbocharging even with only small amounts of exhaust gas, especially at low speeds, high boost pressure ratios, ie high boost pressures can be generated on the inlet side.

The bumping proves to be particularly advantageous in the acceleration of the turbine wheel, d. H. when increasing the turbine speed, which can drop noticeably in idling mode of the engine or at low load and often with increased load request by means of exhaust gas flow should be raised as quickly as possible again. The inertia of the impeller and the friction in the shaft bearing delay usually an acceleration of the impeller to higher speeds and thus an immediate increase in boost pressure.

To be able to use the running in the Abgasabführsystem dynamic wave processes, in particular the Vorlassstöße for the supercharging to improve the performance of the engine, the pressure peaks or Vorlassstöße must be obtained in Abgasabführsystem. It is particularly advantageous if the pressure pulses in the exhaust gas lines increase, but at least do not attenuate or cancel each other out.

The goal is to group the cylinders in such a way or to guide the exhaust pipes together in such a way that the high pressures, in particular the Vorlassstöße the individual cylinders are obtained in Abgasabführsystem and mutual interference is largely avoided.

An internal combustion engine in which the cylinders are grouped is also an object of the present invention. According to the invention, at least two cylinders are configured in such a way that they form at least two groups each having at least one cylinder. The exhaust gas lines of the cylinders of each cylinder group lead together to form an exhaust gas manifold, forming an exhaust gas manifold. The cylinders are configured in such a way that the dynamic wave processes in the exhaust pipes of the cylinders of a group have the least adverse effect.

In the case of a cylinder head with four cylinders arranged in series, it is advantageous in this regard to combine two cylinders which have a firing interval of 360 ° CA, in each case into a cylinder group. If, for example, the ignition in the cylinders is initiated in accordance with the ignition sequence 1 - 2 - 4 - 3 or in accordance with the ignition sequence 1 - 3 - 4 - 2, it is advantageous for the outer cylinders to form a first group and the inner cylinders for a second group summarize.

In connection with the grouping of the cylinders to realize a bump charging, two further aspects must be considered, which are of high relevance with regard to the separation of the exhaust gas removal systems of the cylinder groups. On the one hand, the exhaust manifolds are increasingly being integrated into the cylinder head in order to participate in liquid cooling provided in the cylinder head and not have to manufacture the manifolds from thermally highly resilient materials which are cost-intensive. On the other hand, it is fundamentally endeavored to provide the turbine provided in the exhaust-gas removal system as close as possible to the outlet of the internal combustion engine, i. H. near the outlet openings of the cylinders. This has several reasons and advantages, especially because shorten the exhaust pipes between the cylinders and the turbine. Not only is the path of the hot exhaust gases to the turbine shortened, but also the volume of both the individual exhaust manifolds and the entire Abgasabführsystems upstream of the turbine decreases. The thermal inertia of the Abgasabführsystems also decreases. In this way, the exhaust enthalpy of the hot exhaust gases, which is largely determined by the exhaust pressure and the exhaust gas temperature, optimally utilized and a rapid response of the turbine can be ensured. A shortening of the line lengths and a concomitant reduction of the exhaust gas volume upstream of the impeller improves the response of the turbine.

However, the fact that the distances from the exhaust ports of the cylinders to the turbine significantly shorten according to the concept described above, but can also have disadvantages. Due to the arrangement of the turbine close to the engine and / or the integration of the manifold, the exhaust gas removal systems of the cylinder groups may not be kept separated from each other for a sufficiently long time.

For the reasons mentioned above, according to the invention, a double-flow turbine is used, wherein the exhaust gas removal systems of the cylinder groups are separated from each other up to the at least one impeller of the turbine by means of at least one housing wall. For this purpose, the two total exhaust pipes are connected in the manner with the twin-flow turbine, that in each case an entire exhaust line is connected to one of the two floods of the turbine, the two floods are separated from each other in continuation of the total exhaust gas to the at least one impeller by means of at least one housing and thus also the exhaust gas removal systems of the cylinder groups.

In the prior art, the turbine is usually carried out in radial construction, d. H. the flow of the blades takes place substantially radially. In the context of the present invention, essentially radial means that the velocity component in the radial direction is greater than the axial velocity component. The velocity vector of the flow cuts the shaft of the turbocharger 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 according to the prior art is designed as a spiral or worm casing running all around, so that the inflow of the exhaust gas to the turbine takes place substantially radially. Such a radial turbine is used for example in the EP 1 710 415 A1 described.

Occasionally, the turbine is also designed as an axial turbine, d. H. the flow of the impeller blades takes place substantially axially. In the context of the present invention, essentially axial means that the velocity component in the axial direction is greater than the radial velocity component. The velocity vector of the flow in the region of the impeller preferably runs parallel to the shaft of the exhaust gas turbocharger, if the flow is exactly axial.

In the case of axial turbines, however, the inlet region for supplying the exhaust gas is often designed as a spiral or worm casing running all around, so that the flow of the exhaust gas at least in the inlet region runs or is guided obliquely or radially to the shaft, for which purpose a deflection the exhaust gas is required or is. Decreases in the exhaust gas exhaust gas available at the turbine runner are accepted. The EP 1 710 415 A1 describes such an axial turbine.

In order to use the exhaust energy as efficiently as possible, the exhaust gas should be deflected as little as possible. Any change in direction of the exhaust gas flow, for example as a result of a curvature of the Abgasabführsystems, has a pressure drop in the exhaust gas flow and thus enthalpy loss. Everything should be avoided which reduces the pressure in the exhaust gas and reduces the exhaust gas energy still available at the turbine.

Moreover, the scroll or scroll housings used to form the entrance area make it difficult to separate the two floods, i. H. the separation of Abgasabführsysteme the cylinder groups, up to the at least one impeller. The flow guidance in the inlet region of such turbines is so complex that the provision of a housing wall separating the floods requires structurally complex concepts which, in principle, are associated with high costs.

Against this background, it is the object of the present invention to provide a supercharged internal combustion engine according to the preamble of claim 1, with which the disadvantages known from the prior art are overcome and their charging behavior is improved, in particular with regard to the efficiency.

• – jeder Zylinder mindestens eine Auslassöffnung zum Abführen der Abgase aus dem Zylinder via Abgasabführsystem aufweist und sich an jede Auslassöffnung eine Abgasleitung anschließt,
• – mindestens zwei Zylinder in der Art konfiguriert sind, dass diese zwei Gruppen mit jeweils mindestens einem Zylinder bilden,
• – die Abgasleitungen der Zylinder jeder Zylindergruppe unter Ausbildung eines Abgaskrümmers jeweils zu einer Gesamtabgasleitung zusammenführen,
• – mindestens ein Abgasturbolader vorgesehen ist, der eine im Abgasabführsystem angeordnete zweiflutige Turbine umfasst, und
• – die beiden Gesamtabgasleitungen mit der zweiflutigen Turbine, die mindestens ein in einem Turbinengehäuse auf einer drehbaren Welle gelagertes und mit Laufschaufeln ausgestattetes Laufrad umfasst, in der Art in einem Eintrittsbereichs des Turbinengehäuses verbunden sind, dass jeweils eine Gesamtabgasleitung mit einer der zwei Fluten der Turbine verbunden ist, wobei die zwei Fluten – in Fortsetzung der Gesamtabgasleitungen – bis hin zu dem mindestens einen Laufrad mittels mindestens einer Gehäusewandung voneinander getrennt sind und damit auch die Abgasabführsysteme der Zylindergruppen,

und die dadurch gekennzeichnet ist, dass

• – die Turbine eine zweiflutige Axialturbine ist, und
• – der Eintrittsbereich des Turbinengehäuses koaxial zur Welle der Axialturbine verläuft und ausgebildet ist, so dass die Zuströmung des Abgases im Eintrittsbereich der Turbine im Wesentlichen axial erfolgt, und
• – die mindestens eine Gehäusewandung laufradseitig zumindest abschnittsweise schraubenförmig ausgebildet ist.

This object is achieved by a supercharged internal combustion engine having at least one cylinder head with at least two cylinders, in the

• Each cylinder has at least one outlet opening for discharging the exhaust gases out of the cylinder via the exhaust gas removal system and an exhaust gas line adjoins each outlet opening,
• At least two cylinders are configured in such a way that they form two groups each having at least one cylinder,
• - Combine the exhaust gas lines of the cylinders of each cylinder group to form an exhaust gas manifold, respectively to form an exhaust gas line,
• - At least one exhaust gas turbocharger is provided which comprises a arranged in Abgasabführsystem double-flow turbine, and
• - The two total exhaust gas lines with the twin-bladed turbine, which comprises at least one mounted in a turbine housing on a rotatable shaft and equipped with blades impeller are connected in the manner in an inlet region of the turbine housing, that in each case an overall exhaust gas line connected to one of the two floods of the turbine is, wherein the two floods - in continuation of the total exhaust gas lines - up to the at least one impeller by means of at least one housing wall are separated from each other and thus also the Abgasabführsysteme the cylinder groups,

and which is characterized in that

• - The turbine is a double-flow axial turbine, and
• - The inlet region of the turbine housing is coaxial with the shaft of the axial turbine and is formed, so that the inflow of the exhaust gas in the inlet region of the turbine takes place substantially axially, and
• - The at least one housing wall impeller side is at least partially helical.

The internal combustion engine according to the invention is with a double-flow turbine in Axialbauweise equipped, wherein the inlet region of this axial turbine in the turbine housing is coaxial with the shaft of the turbine and is formed. The radial supply of the exhaust gas to the turbine by means of spiral or worm housing and the associated disadvantages eliminated.

The exhaust gas is not deflected upstream of the at least one impeller of the turbine to be supplied to the at least one impeller. A deflection or change in direction of the exhaust gas flow is omitted, so that unnecessary pressure losses in the exhaust gas flow due to flow deflection can be avoided and the most energy-rich exhaust gas is provided on the impeller.

The use of an axial turbine together with the inventively formed inlet area also allows a very close to the engine arrangement and thus a dense packaging, but especially a reduction of the distance, the volume, the mass and thus the thermal inertia of Abgasabführsystems upstream of the axial turbine.

The coaxial with the shaft of the axial turbine inlet formed in the turbine housing facilitates the separation of the two floods, d. H. the Abgasabführsysteme up to at least one turbine impeller. The axial flow guidance in the entry area allows without constructive effort the introduction of a flood separating the housing wall.

According to the invention, the at least one housing wall is helically designed on the impeller side in order to function as a guide upstream of the at least one impeller. The velocity vector of the flow is replaced by this guide a radial component, whereby the efficiency of the turbine is increased again.

Thus, the object underlying the invention is achieved, namely provided a supercharged internal combustion engine according to the preamble of claim 1, with which the known from the prior art disadvantages are overcome and their charging behavior is improved in particular in terms of efficiency.

The internal combustion engine according to the invention is an internal combustion engine charged by means of an exhaust gas turbocharger. An exhaust-gas turbocharger comprises a turbine arranged in the exhaust-gas removal system and a compressor arranged in the intake system.

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. If the displacement is reduced, then the load spectrum can be shifted to higher loads, where the specific fuel consumption is lower. By charging in combination with suitable transmission designs and a so-called downspeeding can be realized, in which also a lower specific fuel consumption can be achieved. 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 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.

Nevertheless, embodiments of the internal combustion engine may be advantageous in which for the purpose of charging additionally a mechanical charger is provided.

Preferably, a charge air cooling is provided, with which the compressed charge air is cooled before entering the cylinder. As a result, the density of the charge air supplied continues to increase. The cooling also contributes in this way to a compression and better filling of the cylinder. It may be advantageous to equip the intercooler with a bypass line in order to bypass the intercooler when necessary, for example, after a cold start.

The torque characteristic of the supercharged internal combustion engine can be improved by providing a plurality of superchargers, exhaust gas turbochargers and / or mechanical superchargers, arranged in parallel and / or in series.

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

Embodiments of the supercharged internal combustion engine in which the double-flow axial turbine is a segmented axial turbine having two segments are advantageous.

In the above internal combustion engine, the Abgasabführsysteme the cylinder groups are kept apart not only up to the impeller, but also when flowing through the blades of the impeller, d. H. in the wheel. The connection of the Abgasabführsysteme the two cylinder groups is thus arranged even farther away from the outlet openings of the cylinder, whereby the Abgasleitungsmäßig distance between a cylinder of a group and a cylinder of the other group is further increased. A backflow is present only possible via a rotating impeller and thus very difficult.

In this context, embodiments of the internal combustion engine in which each segment is circular are advantageous. In this case, a tide or total exhaust gas line is open inside and circular to the impeller out, the other tide or total exhaust line outside, d. H. the inner flood circular encasing and enclosing, trained and opened to the impeller.

Advantageous embodiments of the internal combustion engine, in which the two floods are separated by means of a single contiguous housing wall to the at least one impeller.

While a more or less large gap is formed in each case between two adjacent housing wall parts in a multi-part housing wall, which permits a certain interaction between the adjacent floods, such a gap does not apply to a one-part housing wall. This supports the original function of the housing wall, namely to separate the neighboring floods as much as possible and to prevent an interaction between the floods.

However, embodiments of the internal combustion engine may nevertheless be advantageous in which the housing wall separating the two floods is of modular design.

Also advantageous embodiments of the internal combustion engine, in which the turbine housing is formed integrally.

A monolithically designed housing is characterized by a low weight and a compact design. A simplified assembly due to the smaller number of components is an advantage of the associated turbine. In addition, the housing is gas-tight due to the lack of component joints. Preferably, the monolithic housing is formed as a cast component, such as aluminum, steel, gray cast iron, thermally highly resilient nickel-containing materials or the like.

Embodiments of the internal combustion engine in which at least one housing wall is an immovable wall fixedly connected to the turbine housing are advantageous. This embodiment of the housing wall ensures that the heat introduced by the hot exhaust gas into the housing wall is dissipated in an advantageous manner and to a sufficient extent into and via the housing.

Embodiments of the internal combustion engine in which the axial turbine has an outlet region for discharging the exhaust gas are advantageous, this outlet region having a spiral housing. A radial outflow of the axial turbine via spiral housing allows a compact design of the drive unit, whereby a dense packaging in the engine compartment is made possible.

Embodiments of the internal combustion engine in which the two exhaust pipes have a semicircular cross section on the impeller side are advantageous, ie. H. are open to the at least one impeller via a semi-circular sector.

Advantageously, embodiments of the internal combustion engine in which the at least one - two adjacent floods separating - housing has at least one wall connecting the two floods, which is closable by means of shut-off.

Embodiments of the internal combustion engine in which the connecting opening is provided on the impeller side are advantageous.

Embodiments of the internal combustion engine may also be advantageous in which the two exhaust manifolds of the two cylinder groups can be connected to one another by releasing at least one overflow channel.

The bump charging not only has advantages. As a rule, the charge cycle deteriorates as a result of the pressure pulses in the exhaust gas removal system. The cylinders of a group can interfere with each other during the charge change, ie impair. The pressure waves emanating from a cylinder, not only run through the at least one exhaust pipe of this cylinder, but also along the exhaust pipes of the other cylinders of this group and possibly up to the provided at the end of the respective line Outlet. Exhaust gas that has already been ejected or discharged into an exhaust gas line during the charge exchange can therefore again enter the cylinder as a result of the pressure wave that emanates from another cylinder. It proves to be disadvantageous, in particular, if overpressure prevails at the outlet opening of one cylinder towards the end of the charge change or if the pressure wave of another cylinder propagates along the exhaust pipe in the direction of the outlet opening, which counteracts the evacuation of the combustion gases from this cylinder. The combustion gases are significantly pushed out in this phase of the charge change as a result of the stroke of the piston. In some cases, even exhaust gas that originates from one cylinder can get into another cylinder before its outlet closes. The deteriorated charge cycle leads to disadvantages especially with increasing load and increasing speed. The exhaust gas in the cylinder, ie the residual gas content remaining in the cylinder, has a significant influence on the knocking behavior of a spark-ignited internal combustion engine, with the risk of knocking combustion increasing with increasing proportion of exhaust gas.

Furthermore, it has to be taken into account that a turbine is operated most effectively without being intermittently and without changing parts. In order to be able to optimally operate the turbine provided downstream of the cylinders in the exhaust gas removal system at high engine speeds, the turbine should be subjected to an exhaust gas pressure that is as constant as possible in time, which is why a slightly changing pressure upstream of the turbine wheel is preferred in order to realize so-called congestion charging.

By a correspondingly large volume of exhaust gas upstream of the turbine impeller, the pressure pulsations in the exhaust pipes can be smoothed. Thus, with regard to accumulation, it is advantageous to connect the exhaust pipes of all cylinders to maximize the exhaust volume of the exhaust system upstream of the turbine and to minimize pressure fluctuations.

In this respect, it is advantageous to provide the possibility of being able to connect the two exhaust gas removal systems of the two cylinder groups by releasing at least one overflow channel or at least one opening.

In this case, a plurality of concepts can be distinguished, for example, a concept in which the two exhaust manifolds of the two cylinder groups connect with each other or can be separated from each other. The exhaust gas discharge system is then configured in accordance with the current objective to be able to charge the engine by disconnecting the exhaust manifolds in accordance with a bumping charge or by connecting the exhaust manifolds according to a bum-up charge. A disadvantage of the concept described above is that the connection of the manifold a connection is realized near the outlet openings of the cylinder.

Alternatively, the floods of the twin-flow turbine via opening in the housing wall are connected to each other or separated. The floods are then either separated from each other or connected to each other, wherein the internal combustion engine is operated and charged by means of shock charging or by means of static charge.

Advantageously, embodiments of the internal combustion engine in which the at least one - two adjacent floods separating - housing wall impeller side has a free tongue-like end, which comes as close as possible to the at least one impeller.

This embodiment aims to minimize the interaction between the exhaust systems, i. H. to increase the degree of separation of the floods or Abgasabführsysteme. The background of this measure is that a more or less large gap between the housing wall and the impeller must remain, so that the impeller can rotate freely without rubbing against the housing wall. In the present case, this gap should be made as narrow as possible.

Embodiments of the internal combustion engine in which the exhaust gas lines of the cylinders of each cylinder group within the cylinder head together to form two exhaust manifolds each lead to an overall exhaust gas line are advantageous.

The provided in Abgasabführsystem double-flow axial turbine can then very close to the outlet of the internal combustion engine, d. H. be arranged close to the outlet openings of the cylinder. This has the advantages already mentioned. The exhaust enthalpy can be optimally used and a fast response of the turbine can be ensured.

The integration of the exhaust manifold in the cylinder head further leads to a compact design of the at least one cylinder head and thus the internal combustion engine according to the invention and allows a dense packaging of the entire drive unit. In addition, in this way it is possible to participate in a liquid cooling system, which may be provided in the cylinder head, so that the manifolds do not have to be manufactured from thermally highly stressable and thus cost-intensive materials.

Embodiments of the internal combustion engine in which at least one exhaust aftertreatment system is provided in the exhaust gas removal system are advantageous; For example, an oxidation catalyst, a three-way catalyst, a storage catalyst, a selective catalyst and / or a particulate filter.

In the following the invention with reference to an embodiment and according to 1 described in more detail. Hereby shows:

1 in a half section and partially cut the double-flow axial turbine of a first embodiment of the internal combustion engine.

1 shows in half section and partially cut the double-flow axial turbine 1 a first embodiment of the internal combustion engine.

The axial turbine 1 has a turbine housing 2 in which an impeller 3 on a rotatable shaft 4 is stored. To pick up the shaft 4 serves a bearing housing 9 ,

The two floods 5 . 6 be right down to the wheel 3 by means of housing walls 2c separated, wherein the exhaust stream of a first cylinder group 7 the first flood 5 and the exhaust gas flow of a second cylinder group 8th the second flood 6 is supplied.

The entrance area 2a of the turbine housing 2 is coaxial with the shaft 4 the axial turbine 1 designed so that the inflow of the exhaust gas to the impeller 3 the axial turbine 1 takes place substantially axially and the exhaust gas in the inlet region 2a is not deflected or does not need to be deflected to the impeller 3 to be fed. Flow losses caused by pressure losses are avoided in this way, so that a high-energy exhaust gas upstream of the impeller 3 provided. The exhaust gas can therefore more energy in the axial turbine 1 be withdrawn. The efficiency is improved, ie increased.

The axial turbine 1 has an all-round spiral housing on the outlet side 2 B over which the exhaust gas in the exit area 2 B the axial turbine 1 is discharged substantially radially. A distribution ring 10 serves to deflect or guide the exhaust gas streams.

The housing wall 2c is impeller-shaped helical and serves as a guide. The velocity vector of the flow upstream of the impeller 3 receives thereby a radial component, whereby the efficiency of the axial turbine 1 is increased.

LIST OF REFERENCE NUMBERS

1

 double-flow axial turbine

2

 turbine housing

2a

 entry area

2 B

 Exit area, spiral housing

2c

 housing

3

 Wheel

4

 Rotation axis, shaft

5

 first tide

6

 second tide

7

 Exhaust flow of the first cylinder group

8th

 Exhaust flow of the second cylinder group

9

 bearing housing

10

 distribution ring

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

• EP 1710415 A1 [0020, 0022]

Claims (12)

Supercharged internal combustion engine having at least one cylinder head with at least two cylinders, in which - each cylinder has at least one outlet opening for discharging the exhaust gases from the cylinder via Abgasabführsystem and connects to each outlet an exhaust pipe, - at least two cylinders are configured in the way that this form two groups, each with at least one cylinder, - merge the exhaust gas lines of the cylinder of each cylinder group to form an exhaust manifold to form an overall exhaust gas line, - at least one exhaust gas turbocharger is provided, which is arranged in the Abgasabführsystem two-flow turbine ( 1 ), and - the two exhaust gas lines with the twin-flow turbine ( 1 ), which at least one in a turbine housing ( 2 ) on a rotatable shaft ( 4 ) and equipped with blades impeller ( 3 ), in the manner in an entry area ( 2a ) of the turbine housing ( 2 ), that in each case a total exhaust gas line with one of the two floods ( 5 . 6 ) of the turbine ( 1 ), the two floods ( 5 . 6 ) - in continuation of the total exhaust gas lines - up to the at least one impeller ( 3 ) by means of at least one housing wall ( 2c ) and thus also the Abgasabführsysteme the cylinder groups, characterized in that - the turbine ( 1 ) a double-flow axial turbine ( 1 ), - the entrance area ( 2a ) of the turbine housing ( 2 ) coaxial with the shaft ( 4 ) of the axial turbine ( 1 ) runs and is formed, so that the inflow of the exhaust gas in the inlet region ( 2a ) of the turbine ( 1 ) takes place substantially axially, and - the at least one housing wall ( 2c ) is at least partially helically formed on the impeller side. Supercharged internal combustion engine according to claim 1, characterized in that the double-flow axial turbine ( 1 ) a segmented axial turbine ( 1 ) with two segments. Supercharged internal combustion engine according to claim 2, characterized in that each segment is circular. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the two floods ( 5 . 6 ) by means of a single contiguous housing wall ( 2c ) up to the at least one impeller ( 3 ) are separated from each other. Supercharged internal combustion engine according to one of the preceding claims, characterized in that at least one housing wall ( 2c ) an immovable and fixed to the turbine housing ( 2 ) connected wall ( 2c ). Supercharged internal combustion engine according to one of the preceding claims, characterized in that the axial turbine ( 1 ) over an exit area ( 2 B ) for discharging the exhaust gas, said exit region ( 2 B ) via a spiral housing ( 2 B ). Supercharged according to one of the preceding claims, characterized in that the two total exhaust pipes impeller side have a semi-circular cross-section. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the at least one - two adjacent floods ( 5 . 6 ) separating housing wall ( 2c ) at least one of the two floods ( 5 . 6 ) having interconnecting opening which is closable by means of a shut-off element. Supercharged internal combustion engine according to claim 8, characterized in that the connecting opening is provided on the impeller side. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the two exhaust manifolds of the two cylinder groups can be connected to each other by releasing at least one overflow channel. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the at least one - two adjacent floods ( 5 . 6 ) separating housing wall ( 2c ) impeller-side has a free tongue-like end which as close as possible to the at least one impeller ( 3 ). Supercharged internal combustion engine according to one of the preceding claims, characterized in that the exhaust gas lines of the cylinder merge each cylinder group within the cylinder head to form two exhaust manifolds in each case to form an overall exhaust gas line.

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