DE202014100754U1 - Charged internal combustion engine with double-flow turbine - Google Patents

Abstract

Supercharged internal combustion engine with 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 the exhaust gas discharge system and an exhaust pipe connects to each outlet opening, - at least two cylinders are configured such that they form two groups with at least one cylinder each, - combine the exhaust pipes of the cylinders of each cylinder group to form an exhaust manifold to form a total exhaust pipe, and - the two total exhaust pipes with a double-flow turbine (1), which has at least one in a turbine housing (2) on one Rotatable shaft (4) bearing impeller (3) are connected in such a way that a total exhaust pipe is connected to one of the two flows (8, 9) of the double-flow turbine (1), the two flows (8, 9) to the at least one impeller (3) by means of the housing wall (5) are separated from one another and can be connected to one another within the turbine housing (2) by opening at least one overflow channel (14) upstream of the at least one impeller (3), characterized in that - at least one translationally displaceable piston-like shut-off element (15) is provided, which is in a In the rest position, the two flows (8, 9) of the turbine (1) are separated from one another, in a first working position the two flows (8, 9) of the turbine (1) are connected by releasing the overflow channel (14) and in a second working position the two Connects floods (8, 9) of the turbine (1) by releasing the overflow channel (14) and releases a blow-off line (13) which branches upstream of the at least one impeller (3) from the exhaust gas discharge system.

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 sie zwei Gruppen mit jeweils mindestens einem Zylinder bilden,
• – die Abgasleitungen der Zylinder jeder Zylindergruppe unter Ausbildung eines Abgaskrümmers jeweils zu einer Gesamtabgasleitung zusammenführen, und
• – die beiden Gesamtabgasleitungen mit einer zweiflutigen Turbine, die mindestens ein in einem Turbinengehäuse auf einer drehbaren Welle gelagertes Laufrad umfasst, in der Art verbunden sind, dass jeweils eine Gesamtabgasleitung mit einer der beiden Fluten der zweiflutigen Turbine verbunden ist, wobei die beiden Fluten bis hin zu dem mindestens einen Laufrad mittels Gehäusewandung voneinander getrennt sind und innerhalb des Turbinengehäuses durch Freigeben mindestens eines Überströmkanals stromaufwärts des mindestens einen Laufrades miteinander verbindbar sind.

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 cylinder of each cylinder group to form an exhaust manifold to form an overall exhaust line, and
• - The two total exhaust gas lines with a twin-bladed turbine, which comprises at least one mounted in a turbine housing on a rotatable shaft impeller, are connected in such a way that in each case an overall exhaust gas line is connected to one of the two floods of the twin-bladed turbine, the two floods up to the at least one impeller by means of housing wall are separated from each other and within the turbine housing by releasing at least one overflow upstream of the at least one impeller are connected to each other.

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 a cylinder head, which are connected to form the cylinder. 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 charge exchange, the exhaust of the combustion gases via the outlet openings of the at least two cylinders and the filling of the combustion chambers, d. H. the intake of the fresh mixture or the 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 concrete design of the Abgasabführsystems depends essentially on which operating ranges, the performance of the internal combustion engine to be optimized.

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. When, at the beginning of the charge cycle, the exhaust valve opens near bottom dead center, the combustion gases flow at high speed through the exhaust port into the exhaust system due to the high pressure level prevailing in the cylinder at the end of the 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 not evacuated pressure driven, but are ejected as a result of the stroke of the piston.

At low loads or speeds, ie small amounts of exhaust gas, the pre-discharge shock can be used advantageously for the supercharging, which also high turbine pressure ratios are achieved at low turbine speeds can. In this way, by means of turbocharging even with only small amounts of exhaust gas, ie at low loads or low speeds, high boost pressure ratios, ie high boost pressures are 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 at least one 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 fluctuations in the exhaust pipes increase, but at least not attenuate or cancel each other out.

It is therefore desirable to group the cylinders in such a way or to merge the exhaust pipes in such a way that the high pressures, in particular the Vorlassstöße the individual cylinders are obtained in Abgasabführsystem.

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 two groups, each with 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 a cylinder head with four cylinders arranged in series, it is advantageous in this regard, two cylinders, which have a firing interval of 360 ° KW, each to form a cylinder group together. For example, the ignition in the cylinders according to the firing order 1 - 2 - 4 - 3 or according to the firing order 1 - 3 - 4 - 2 initiated, it is advantageous to combine the outer cylinder to a first group and the inner cylinder to a second group.

The bumping but also has disadvantages. As a rule, the charge cycle deteriorates as a result of pressure fluctuations in the exhaust gas removal system. The cylinders of a group can interfere with each other during the charge cycle, d. H. affect. 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 each pipe 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, d. H. the residual gas content remaining in the cylinder has a decisive influence on the knocking behavior of a spark-ignited internal combustion engine, whereby the risk of knocking combustion increases with increasing proportion of exhaust gas.

Furthermore, it must be taken into account that a turbine is operated most effectively without intermittent and without alternating partial loading. In order to be able to optimally operate a 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 is preferred in order to realize a so-called congestion charging.

By a correspondingly large volume of exhaust gas upstream of the turbine, the pressure pulsations in the exhaust pipes can be smoothed. In this respect, the grouping of the cylinders, in which the exhaust pipes are combined in groups, whereby the volume of Abgasabführsystems upstream of the turbine is divided into several sub-volumes proves to be counterproductive.

Rather, it would be advantageous in terms of congestion, the exhaust pipes all Combine cylinder into a single overall exhaust line to increase the exhaust gas volume of Abgasabführsystems upstream of a turbine disposed in this entire exhaust line largely as possible, ie to maximize and minimize the pressure fluctuations.

In the optimization of the Abgasabführsystems both in terms of low engine speeds and high engine speeds or in optimizing the Abgasabführsystems both in terms of small amounts of exhaust gas as well as in terms of larger amounts of exhaust thus results in the design of Abgasabführsystems a conflict of goals. A grouping of the cylinders for the realization of a bumping leads to a favorable performance at low engine speeds, whereas disadvantages are to be taken into account at higher engine speeds. If, on the other hand, the largest possible volume of exhaust gas is realized upstream of the turbine, in order to be able to use the advantages of a static charge at higher engine speeds, the performance at low speeds, the so-called low end torque, deteriorates.

Concepts are known from the prior art in which the two exhaust manifolds of the two cylinder groups can be connected or separated from one another. The exhaust gas discharge system is then configured in dependence on the rotational speed or the gas dynamics in order to be able to charge the internal combustion engine by disconnecting the exhaust manifolds in accordance with a bumping charge and by connecting the exhaust manifolds in accordance with a backup charge.

A disadvantage of the above-described concept is that the connection of the manifold a connection is realized near the outlet openings of the cylinder, whereby the residual gas problem or the related Klopfproblematik described above receives feed, d. H. is aggravated.

In light of the above, it is the object of the present invention to provide a supercharged internal combustion engine according to the preamble of claim 1, which allows optimized operation over the entire operating range, in particular both at low speeds and at higher speeds.

• – 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 sie zwei Gruppen mit jeweils mindestens einem Zylinder bilden,
• – die Abgasleitungen der Zylinder jeder Zylindergruppe unter Ausbildung eines Abgaskrümmers jeweils zu einer Gesamtabgasleitung zusammenführen, und
• – die beiden Gesamtabgasleitungen mit einer zweiflutigen Turbine, die mindestens ein in einem Turbinengehäuse auf einer drehbaren Welle gelagertes Laufrad umfasst, in der Art verbunden sind, dass jeweils eine Gesamtabgasleitung mit einer der beiden Fluten der zweiflutigen Turbine verbunden ist, wobei die beiden Fluten bis hin zu dem mindestens einen Laufrad mittels Gehäusewandung voneinander getrennt sind und innerhalb des Turbinengehäuses durch Freigeben mindestens eines Überströmkanals stromaufwärts des mindestens einen Laufrades miteinander verbindbar sind,

und die dadurch gekennzeichnet ist, dass

• – mindestens ein translatorisch verschiebbares kolbenartiges Absperrelement vorgesehen ist, welches in einer Ruheposition die beiden Fluten der Turbine voneinander trennt, in einer ersten Arbeitsposition die beiden Fluten der Turbine durch Freigeben des Überströmkanals miteinander verbindet und in einer zweiten Arbeitsposition die beiden Fluten der Turbine durch Freigeben des Überströmkanals miteinander verbindet sowie eine Abblaseleitung freigibt, die stromaufwärts des mindestens einen Laufrades aus dem Abgasabführsystem abzweigt.

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 cylinder of each cylinder group to form an exhaust manifold to form an overall exhaust line, and
• - The two total exhaust gas lines with a twin-bladed turbine, which comprises at least one mounted in a turbine housing on a rotatable shaft impeller, are connected in such a way that in each case an overall exhaust gas line is connected to one of the two floods of the twin-bladed turbine, the two floods up to the at least one impeller are separated from each other by means of housing wall and within the turbine housing by releasing at least one overflow channel upstream of the at least one impeller are connected to each other,

and which is characterized in that

• - At least one translationally displaceable piston-like shut-off is provided, which separates the two floods of the turbine in a rest position, in a first working position, the two floods of the turbine by releasing the overflow channel connects and in a second working position, the two floods of the turbine by releasing the Overflow channel connects to each other and releases a blow-off, which branches off upstream of the at least one impeller from the Abgasabführsystem.

In the internal combustion engine according to the invention, the volume of the Abgasabführsystems communicating with a single trough of the turbine can be varied by connecting or disconnecting the two floods of the turbine.

Consequently, the exhaust gas volume or the Abgasabführsystem upstream of the at least one impeller of the twin-flow turbine to different operating conditions of the internal combustion engine, in particular to different levels of exhaust gas or different speeds, adapted and optimized in this regard.

Compared with the connection of the two exhaust manifolds, the inventive connecting the two floods of the turbine has the advantage that the at least one exhaust gas volume of the two cylinder groups connecting overflow is located farther away from the outlet openings of the cylinder, whereby the exhaust gas line route between a cylinder of a group and a cylinder of the other group is increased. The risk of mutual, in particular adverse influence on the change of charge is counteracted by this. The residual gas problem or knocking problem described above defuses or disappears.

The above-described relationships and effects are particularly relevant in supercharged internal combustion engines, in which the exhaust gas lines of the cylinders of each cylinder group each merge within the cylinder head to form an exhaust manifold to an overall exhaust line, of high relevance, since by connecting the manifold a connection would be realized, the would be placed exceptionally close to the outlet ports of the cylinders.

Thus, the object underlying the invention is achieved, namely provided a supercharged internal combustion engine according to the preamble of claim 1, which allows optimized operation over the entire operating range, in particular both at low speeds and at higher speeds.

According to the invention a piston-like shut-off element is provided, which is designed to be translationally displaceable. In the rest position of the shut-off the two floods of the turbine are separated from each other and the charging of the internal combustion engine by means of shock charging. By transferring the shutoff element into a first working position, an overflow channel is released, which connects the two floods to realize a jam charge. Starting from a first working position, a blow-off line is released by further displacement of the piston-like shut-off element into a second working position, by means of which exhaust gas can be guided past the turbine. For this purpose, the blow-off line branches off upstream of the at least one impeller from the Abgasabführsystem.

The shut-off element according to the invention has over other shut-off elements, such as flaps and the like, numerous advantages, in particular with regard to the tightness, the setting of the amount of exhaust gas blown off and the thermal capacity. The high thermal stress of the shutoff results from the arrangement in the turbine housing.

The conflict of objectives known from the state of the art, which results from the different requirements of accumulating charge or accumulating charge on the exhaust gas volume located upstream of the at least one impeller, namely to provide a small volume for realizing a collision charge at low speeds in order to control the gas dynamics with high pressure impulses maintain, and on the other hand for the purpose of a charge accumulation at higher speeds as large a volume to reduce the pressure peaks and to smooth the exhaust pressure available to be resolved.

At high gas dynamics, the two floods of the turbine and thus the exhaust systems of the cylinder groups remain separated, so that each flood communicates only with the exhaust pipes of the cylinder group, from which it is originally fed. The exhaust gas volume upstream of a flood is determined by the volume of the exhaust pipes of the associated manifold and the volume of the total exhaust gas line, which connects the manifold with the inlet opening of the corresponding turbine tide.

The comparatively small volumes upstream of the at least one impeller permit bump charging. By exploiting the pressure peaks propagating in the exhaust manifolds, the available energy can then be used advantageously at high turbine efficiencies. When using the turbine as part of an exhaust turbocharging in this way the boost pressure can be increased at low engine speeds.

The pressure fluctuations in the exhaust gas removal system, which are to be regarded as detrimental in the context of congestion charging at high engine speeds, can be smoothed out, at best even eliminated, by connecting the two flows of the turbine. The volumes of Abgasabführsystems be merged upstream of the at least one impeller. Each individual flood then no longer communicates only with the exhaust system volume of the cylinder group assigned to it, but also with the exhaust system volume of the other cylinder group. It is thus provided an additional volume each flood, which increases the exhaust gas volume upstream of each flood or upstream of the impeller instead of two small volumes, a large volume is available. This increase in volume ensures a little changing, substantially constant exhaust gas pressure upstream of the at least one impeller and thus favorable conditions for congestion charging at higher speeds or larger amounts of exhaust gas.

The inlet region of a double-flow turbine has two inlet channels. Multi-flow turbines are therefore particularly suitable for supercharged internal combustion engines, in which the exhaust pipes of the cylinders are combined in groups in order to realize a shock charging. By means of the two floods of the twin-flow turbine which can be connected to one another according to the invention, it is possible to change between shock charging and accumulation charging. The turbine can basically be equipped with a variable turbine geometry, the can be adjusted by adjusting to the respective operating point of the internal combustion engine.

In the internal combustion engine according to the invention, the exhaust gas lines of at least two cylinders are brought together to form two exhaust gas manifolds to two total exhaust gas lines. In this respect, embodiments with three, four, five or more cylinders, in which the exhaust pipes of more than two cylinders are combined to form two total exhaust pipes, are also internal combustion engines according to the invention.

Embodiments may be advantageous in which the at least one shut-off element is electrically, hydraulically, pneumatically, mechanically or magnetically controllable, preferably by means of the engine control of the internal combustion engine.

The at least one shut-off can be adjusted in stages, d. H. switchable, be executed, in the way that it alternates between the rest position and multiple working positions and the overflow channel or the Abblaseleitung either closes or releases, which simplifies the control and in particular offers cost advantages.

However, the at least one shut-off element is preferably infinitely adjustable, for example, a sudden torque drop or torque increase when sliding the shut-off, d. H. to avoid the transition from bump charging to congestion charging and vice versa. Stepless shifting also makes it possible to adjust the amount of exhaust gas bypassed via the blow-off line. H. to be measured in a predeterminable way.

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

Advantageous embodiments of the supercharged internal combustion engine, in which the at least one piston-like shut-off element has a free punch-like end, which faces the floods. The stamped end ensures a high mechanical and thermal load capacity of the shut-off element; in particular compared to a flap or a displaceable thin and therefore bendable housing wall. By storage of the stamp-like end in a recess of the turbine housing can be taken care of a sufficient tightness and satisfactory separation of the floods in the rest position of the shut-off.

In this connection, embodiments of the supercharged internal combustion engine in which the free, stamp-like end in the rest position of the at least one piston-like shut-off element is stored in a first recess, which is provided in the turbine housing, are also advantageous.

With the piston-like shut-off adjacent floods can not only be connected together or separated from each other. Rather, by stepless displacement of the punch-like end in the recess on the flow cross-section of the overflow channel and thus on the extent of the interaction between the floods can be influenced. The separation behavior of the floods, d. H. the degree of separation can be influenced directly.

Embodiments of the supercharged internal combustion engine in which the free, stamp-type end has a first cylindrical section are advantageous. The cylindrical portion of the free punch-like end, in cooperation with a first recess corresponding in shape, ensures that there is no jamming of the shut-off element upon rotation of the shut-off element. In addition, a pointed, d. H. tapered tapered end serve as centering when retracting the shutoff in the first recess.

Embodiments of the supercharged internal combustion engine in which the free, stamp-like end merges into a second thickened section to form a transition region, which cross section has a larger cross section than the stamped end, are advantageous. The second thickened portion serves to support the shut-off element when moving, d. H. in every position.

Characterized in that the second portion has a larger cross-section, a transition region is formed, which tapers from the second thickened portion to the punch-like end. This design of the shut-off advantageously allows the control of the amount of exhaust gas blown off in the second working position with interconnected floods.

In this context, embodiments of the supercharged internal combustion engine in which the second thickened section is cylindrical are advantageous. The reasons are those already mentioned in connection with the cylindrical shape of the first section, which is why reference is made to the corresponding statements.

In this connection, furthermore, embodiments of the supercharged internal combustion engine in which the transition region is funnel-shaped are advantageous.

Embodiments of the supercharged internal combustion engine in which the transition region is frusto-conical are advantageous.

In this context, embodiments of the supercharged internal combustion engine are advantageous, in which the transitional area in the rest position of the at least one piston-like shut-off element is stored in a second recess which is provided in the turbine housing and whose shape corresponds to that of the transitional area.

Advantageous embodiments of the supercharged internal combustion engine, in which the at least one piston-like shut-off element between the rest position and a first working position is switchable.

This embodiment of the shut-off element allows separation and connection of the adjacent floods, whereas the separation behavior of the floods, i. H. the degree of separation, can not be influenced, since this requires a continuous displacement of the shutoff.

Therefore, embodiments of the supercharged internal combustion engine in which the at least one piston-like shut-off element is infinitely adjustable are also advantageous.

Particularly advantageous embodiments of the supercharged internal combustion engine, in which the at least one piston-like shut-off element between a first working position and a second working position for the purpose of adjusting the amount of exhaust gas blown off is infinitely adjustable.

Such a configuration of the shutoff allows infinite control of the amount of exhaust gas blown off in the second working position with interconnected floods, d. H. a precise dosage of the exhaust gas flow past the turbine or the at least one impeller.

Embodiments of the supercharged internal combustion engine in which the twin-flow turbine is a double-flow turbine are advantageous.

Embodiments in which the twin-flow turbine is a double-flow turbine are advantageous in which the two floods are arranged in a section perpendicular to the axis of rotation of the at least one impeller and surround the at least one impeller spirally on radii of different sizes at least along an arcuate section.

A double-flow turbine has a higher efficiency compared to the twin-flow turbine and an improved flow behavior of the impeller. In addition, the double-flow turbine is thermally more resilient. The latter advantage results from the arrangement of the floods one above the other.

Embodiments of the supercharged internal combustion engine in which the twin-flow turbine is a twin-flow turbine are also advantageous.

Embodiments in which the twin-flow turbine is a twin-flow turbine in which the two floods are arranged next to each other and which surround at least one impeller spirally at equal radii along at least one arcuate section are advantageous.

Embodiments of the supercharged internal combustion engine in which the housing wall is an immovable wall fixedly connected to the 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 supercharged internal combustion engine in which the blow-off line opens downstream of the at least one impeller into the exhaust-gas removal system are advantageous. This embodiment makes it possible to treat both the exhaust gas blown off and the exhaust gas passed through the turbine in a common exhaust gas aftertreatment system provided in the exhaust gas removal system.

Embodiments of the supercharged internal combustion engine in which the exhaust gas lines of the cylinders of each cylinder group within the cylinder head, with the formation of two exhaust manifolds, in each case combine to form an overall exhaust gas line, are advantageous.

The dual-flow turbine provided in the exhaust-gas removal system can then be located very close to the outlet of the internal combustion engine, i. H. be arranged close to the outlet openings of the cylinder. This has several advantages, especially because shorten the exhaust pipes between the cylinders and the turbine.

As the path to the turbine for the hot exhaust gases is shortened, the volume of the exhaust manifold or Abgasabführsystems decreases upstream of the turbine. The thermal inertia of the Abgasabführsystems also decreases by reducing the mass and the length of the involved exhaust pipes.

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.

The proposed measure further leads to a compact design of the cylinder head and thus the internal combustion engine according to the invention and allows a dense packaging of the entire drive unit.

The shortening of the line lengths and the concomitant reduction of the exhaust gas volume upstream of the turbine support the boost charging in the lower load or speed range.

Embodiments of the supercharged internal combustion engine in which the overflow channel is arranged on the impeller side, are advantageous. H. upstream of the at least one impeller and adjacent to the impeller. As a result, the exhaust-gas route between the cylinder groups is further extended, in particular also in comparison to arranging the overflow channel in the inlet region of the turbine. The risk of reciprocal, in particular disadvantageous influencing the change of charge is thus further counteracted.

For operating a supercharged internal combustion engine of the type described above, the two floods of the turbine are connected by moving the at least one piston-like shutoff element, starting from the rest position into a first working position, in particular in order to switch from the supercharging to the jam charging.

It is advantageous to connect the two floods of the turbine with each other, as soon as the speed n _{mot of} the internal combustion engine exceeds a predetermined speed n _{mot, down} .

It is also advantageous to connect the two floods of the turbine with each other as soon as the amount of exhaust gas exceeds a first predetermined amount of exhaust gas.

Preferably, the two floods of the turbine are connected to each other when the speed n _{mot of} the internal combustion engine exceeds a predetermined speed n _{mot, down} or the exhaust gas amount of the two cylinder groups exceeds the first predetermined amount of exhaust gas and for a predetermined period .DELTA.t _{1 is} greater than this predetermined speed or the first predetermined amount of exhaust gas.

The introduction of an additional condition for the connection of the two floods to prevent too frequent mode change between supercharging and accumulation charging, in particular a transition to congestion charging when the speed or exhaust gas only briefly exceeds the predetermined value and then falls again or by the predetermined value fluctuates without the passing would warrant a transition to congestion charging.

It is advantageous to release the blow-off line by moving the at least one shut-off element when the amount of exhaust gas of the two cylinder groups exceeds a second predetermined amount of exhaust gas, for which purpose the at least one shut-off element is moved to a second working position.

Preferably, the amount of exhaust gas guided past the at least one impeller via blow-off line is set by moving the at least one shut-off element within the second working position.

Starting from interconnected floods, the two floods of the turbine are advantageously separated from one another by displacing the at least one shut-off element into the rest position when the speed or the exhaust gas quantity of the two cylinder groups falls below a predetermined value.

In the following the invention with reference to an embodiment and the 1a . 1b . 1c . 2a . 2 B . 2c and 2d described in more detail. Hereby shows:

1a schematically the basic structure of a double-flow turbine cut perpendicular to the axis of rotation of the impeller,

1b schematically the basic structure of a twin-flow turbine cut perpendicular to the axis of rotation of the impeller,

1c schematically the in 1b illustrated twin stream turbine along the in 1b indicated section AA,

2a schematically and along the in 2d Line AA, partially cut away, shows a fragment of the housing of the double-flow turbine of a first embodiment of the supercharged internal combustion engine with a shut-off element in the rest position.

2 B schematically and along the in 2d Marked line AA partly cut the in 2a Housing fragment shown with a located in a first working position shut-off,

2c schematically and along the in 2d Marked line AA partly cut the in 2a Housing fragment shown with a located in a second working position shut-off, and

2d schematically in plan view and partly perpendicular to the direction of displacement of the shut-off cut into the 2a . 2 B and 2c illustrated housing fragment.

1a shows schematically the basic structure of a double-flow turbine 12 cut perpendicular to the axis of rotation 4 of the impeller 3 ,

The illustrated double-flow turbine 12 is an example of a twin-flow turbine 1 ie for a turbine 1 with two floods 8th . 9 , The turbine 1 has a turbine housing 2 in which an impeller 3 on a rotatable shaft 4 is stored.

The double-flow turbine 12 is characterized in that the two floods 8th . 9 are arranged one above the other and the impeller 3 at least along an arcuate portion spirally enclose on different radii. The two inlet openings 6 . 7 the double-flow turbine 12 are in a flange 10 of the housing 2 radially differently spaced apart from the shaft 4 the turbine 1 arranged, being attached to each inlet 6 . 7 a flood 8th . 9 the turbine 1 connects and the two floods 8th . 9 up to the wheel 3 by means of housing wall 5 are separated from each other. In this way, the exhaust gas flows of the two floods 8th . 9 separated from each other on the impeller 3 directed. Both floods 8th . 9 are to the wheel 3 each open over a circular arc segment of 180 °.

The 1b and 1c schematically show the basic structure of a twin-flow turbine 11 , where it is 1b around a section perpendicular to the axis of rotation 4 of the impeller 3 acts and 1c the twin power turbine 11 along the in 1b marked AA shows.

It should only the differences to the in 1a are discussed, which is why reference is otherwise made to 1a and the corresponding description. The same reference numerals have been used for the same components.

The twin power turbine 11 is characterized in that the two floods 8th . 9 are arranged side by side and the impeller 3 at least along an arcuate portion spirally enclose on equal radii. The two inlet openings 6 . 7 the twin-stream turbine 11 are radially equidistant from the shaft 4 the turbine 1 in the case 5 arranged.

The housing wall 5 the twin-stream turbine 11 is at its free end thermally much higher load than that of the double-flow turbine 12 , in particular in the transition region to the impeller 3 , like out 1c is apparent.

The 2a . 2 B . 2c and 2d show schematically and partly cut a fragment of the housing 2 the twin-flow turbine 1 A first embodiment of the supercharged internal combustion engine with a shut-off 15 in different positions.

It will be complementary to the 1a . 1b and 1c Otherwise, reference is made to these figures and the associated description of the figures. The same reference numerals have been used for the same components.

2a shows schematically and along the in 2d marked line AA partly cut the fragment of the housing 2 a twin-flow turbine 1 with a shut-off element in the rest position 15 ,

To the two by means of housing wall 5 inside the turbine housing 2 separate floods 8th . 9 the turbine 1 by releasing or blocking an overflow channel 14 upstream of the impeller connect or separate from each other, is a piston-like shut-off 15 provided along its longitudinal axis 15e is translationally displaceable. In the rest position shown are the two floods 8th . 9 the turbine 1 separated from each other.

The piston-like shut-off element 15 has a free stamped end 15a that the floods 8th . 9 facing and a first cylindrical portion 15b which, in the rest position in a first recess 5a of the turbine housing 2 is stored.

Along the longitudinal axis 15e of the shutoff element 15 go the free stamped end 15a forming a transitional area 15c in a second thickened section 15d over, which has a larger cross-section than the stamp-like end 15a or the first cylindrical section 15b of the stamp-like finish 15a , At the in 2a embodiment shown are the transition region 15c frusto-conical and the second thickened section 15d cylindrically shaped. The transition area 15c stores in the rest position of the shut-off element 15 in a second recess 5c of the turbine housing 2 whose shape coincides with that of the transition area 15c corresponds. The second thickened section 15d serves to store the shut-off element 15 when moving, ie in any position, including the second section 15d in a third recess 5d of the housing 2 is slidably mounted. The blow-off line 13 is locked here.

By transferring the piston-like shut-off element 15 in a first working position is an overflow 14 released and the two floods 8th . 9 the turbine 1 are linked together, as in 2 B shown. The exchange of exhaust gas between the floods 8th . 9 The so-called overflowing is symbolized by the arrows.

By a further displacement of the shut-off element 15 in a second working position leaves the stamp-like end 15a the first recess 5a , causing the two floods 8th . 9 be connected to each other and a blow-off line 13 is released, like 2c can be removed. The blow-off line 13 branches off the exhaust gas removal system upstream of the impeller and carries the exhaust gas to the impeller of the turbine 1 past. The via blow-off line 13 on the wheel 3 Passing off the amount of exhaust gas can be achieved by moving the shut-off element 15 be precisely set within the second working position.

2d shows schematically and partly perpendicular to the direction of displacement 15e of the shutoff element 15 cut that into the 2a . 2 B and 2c illustrated housing fragment 2 ,

LIST OF REFERENCE NUMBERS

1

 twin-flow turbine

2

 Turbine housing, housing fragment

3

 Wheel

4

 Rotation axis, shaft

5

 housing

5a

 first recess in the turbine housing

5c

 second recess

5d

 third recess

6

 first entrance opening

7

 second inlet

8th

 first tide

9

 second tide

10

 flange

11

 twin turbine

12

 Double-flow turbine

13

 blow-off line

14

 overflow

15

 piston-like shut-off element

15a

 free stamped end

15b

 first section

15c

 Transition area

15d

 second part

15e

 Displacement direction, longitudinal axis

Claims (18)

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 from the cylinder via Abgasabführsystem and connects to each outlet an exhaust pipe, - at least two cylinders are configured in the way that they form two groups, each with at least one cylinder, - combine the exhaust gas lines of the cylinders of each cylinder group to form an exhaust gas manifold in each case to form an overall exhaust gas line, and - the two total exhaust gas lines with a twin-flow turbine ( 1 ), which at least one in a turbine housing ( 2 ) on a rotatable shaft ( 4 ) stored impeller ( 3 ), are connected in such a way that in each case a total exhaust gas line with one of the two floods ( 8th . 9 ) of the twin-flow turbine ( 1 ), the two floods ( 8th . 9 ) up to the at least one impeller ( 3 ) by means of housing wall ( 5 ) are separated from each other and within the turbine housing ( 2 ) by releasing at least one overflow channel ( 14 ) upstream of the at least one impeller ( 3 ) are connectable to each other, characterized in that - at least one translationally displaceable piston-like shut-off element ( 15 ) is provided, which in a rest position, the two floods ( 8th . 9 ) of the turbine ( 1 ) separates, in a first working position the two floods ( 8th . 9 ) of the turbine ( 1 ) by releasing the overflow channel ( 14 ) and in a second working position the two floods ( 8th . 9 ) of the turbine ( 1 ) by releasing the overflow channel ( 14 ) and a blow-off line ( 13 ), the upstream of the at least one impeller ( 3 ) branches off from the Abgasabführsystem. Supercharged internal combustion engine according to claim 1, characterized in that the at least one piston-like shut-off element ( 15 ) a free stamped end ( 15a ), which floods ( 8th . 9 ) is facing. Supercharged internal combustion engine according to claim 2, characterized in that the free punch-like end ( 15a ) in the rest position of the at least one piston-like shut-off element ( 15 ) in a first recess ( 5a ) stored in the turbine housing ( 2 ) is provided. Supercharged internal combustion engine according to claim 2 or 3, characterized in that the free punch-like end ( 15a ) a first cylindrical portion ( 15b ) having. Supercharged internal combustion engine according to one of claims 2 to 4, characterized in that the free punch-like end ( 15a ), forming a transitional area ( 15c ) into a second thickened section ( 15d ), which has a larger cross-section than the stamp-like end ( 15a ). Supercharged internal combustion engine according to claim 5, characterized in that the second thickened portion ( 15d ) is cylindrical. Supercharged internal combustion engine according to claim 5 or 6, characterized in that the transition region ( 15c ) is funnel-shaped. Supercharged internal combustion engine according to one of claims 5 to 7, characterized in that the transition region ( 15c ) is frusto-conical. Supercharged internal combustion engine according to one of claims 5 to 8, characterized in that the transition region ( 15c ) in the rest position of the at least one piston-like shut-off element ( 15 ) in a second recess ( 5c ) stored in the turbine housing ( 2 ) is provided and whose shape with the transition area ( 15c ) corresponds. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the at least one piston-like shut-off element ( 15 ) is switchable between the rest position and a first working position. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the at least one piston-like shut-off element ( 15 ) is infinitely adjustable. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the at least one piston-like shut-off element ( 15 ) is infinitely adjustable between a first working position and a second working position for the purpose of setting the amount of exhaust gas blown off. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the twin-flow turbine ( 1 ) a double-flow turbine ( 12 ). Supercharged internal combustion engine according to one of claims 1 to 12, characterized in that the twin-flow turbine ( 1 ) a twin-flow turbine ( 11 ). Supercharged internal combustion engine according to one of the preceding claims, characterized in that the housing wall ( 5 ) an immovable and fixed to the housing ( 2 ) connected wall. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the blow-off line ( 13 ) downstream of the at least one impeller ( 3 ) opens into the Abgasabführsystem. 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. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the at least one overflow channel ( 14 ) is arranged impeller side.

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