DE102015212045A1 - Exhaust system for an internal combustion engine and internal combustion engine - Google Patents

Abstract

The invention relates to an exhaust system (3) for an internal combustion engine (1) with at least two exhaust gas flows (17, 19), wherein in each exhaust gas flow (17, 19) at least one particulate filter element (7) is arranged, and / or with at least two fluidically Particle filter elements (7) arranged parallel to one another. An adjusting device (9) is provided with which an exhaust gas flow in the exhaust system (3) can be distributed variably to the at least two exhaust gas flows (17, 19) and / or to the at least two fluidically arranged particle filter elements (7).

Description

The invention relates to an exhaust system for an internal combustion engine and an internal combustion engine with such an exhaust system.

In exhaust systems containing particulate filter elements, these not only collect soot particles, which can be burned off again by oxidation in the particulate filter, but also non-combustible, inorganic compounds, which are referred to as ash. These may originate in particular from lubricating oil of an internal combustion engine or from a fuel used. The ash is accumulated over the service life of the particulate filter in this and reduces the free flow-through volume and / or the cross-section of the inlet channels. This leads to an increase in the back pressure over the operating time, which adversely affects fuel consumption and engine performance. The deposition of the ash along the porous filter wall of a particle filter element is clearly more disadvantageous than a collection of ash at the end of channels of the particle filter element as a plug or so-called "plug". It is therefore desirable to deposit the as completely as possible plug shape, and this with the highest possible density, in particular bulk density, whereby in particular an interval between two cleaning steps of the particulate filter element of ash significantly extended and thus the operational readiness of an operated with the particulate filter element internal combustion engine can be increased can. Another problem is that in particular depends on a calibration of an internal combustion engine, with which the exhaust system is operated, and / or depending on a load spectrum of an application for the internal combustion engine, in addition to or instead of a passive regeneration, in which soot in a particulate filter element by in Exhaust gas existing nitrogen dioxide is oxidized, an active regeneration may be necessary, the exhaust gas may need to be heated by an additional heater, because the internal combustion engine itself can not provide a sufficiently high exhaust gas temperature. For heating the exhaust gas may be provided a conversion of chemical energy from a fuel into heat or an electric heater. To heat the entire exhaust gas, a large amount of energy is necessary, which reduces the economic efficiency of the operation of the internal combustion engine. Furthermore, it is advantageous to carry out an active regeneration in the entire operating map for controlling the soot loading in the particulate filter. In the case of active regeneration at nominal load, the power requirement for regeneration can be up to 30% of the rated power of the motor, ie for example for an application with 2400 kW nominal power, the heating power can be about 800 kW or twice for a twin-flow version 400 kW. Heating systems that can provide adequate heating power are large, complicated and expensive. Space-saving and cost-effective heating systems, however, have heating powers, for example of 120 kW, which can not be used for large internal combustion engines with high nominal power. However, it would be possible in principle to use a heating device with smaller heating power even in an internal combustion engine with higher nominal power, if it was possible to reduce the exhaust gas flow through a flow region in which and for which the heating device is provided.

On the other hand, however, for a successful ash mobilization, ie in particular for the transport of ash deposited on a channel wall of a particle filter element towards the channel end, high channel velocities are required in the particle filter element. Thus, here conflicting requirements arise on the one hand with regard to a reduced exhaust gas flow to reduce the heating power required for active regeneration, and on the other hand in view of a high channel velocity to mobilize the deposited ash on walls. While the individual problems of ash mobilization on the one hand and the available heating capacity for active regeneration on the other hand can only be improved if existing exhaust gas systems are improved, there is in any case a need for improvement with regard to a combined solution for the conflicting goals.

The invention has for its object to provide an exhaust system and an internal combustion engine in which the disadvantages mentioned do not occur.

The object is achieved by providing the subject matters of the independent claims. Advantageous embodiments will become apparent from the dependent claims and the description.

The object is achieved in particular by providing an exhaust system for an internal combustion engine, which has at least two exhaust gas flows, wherein in each exhaust gas flow at least one particulate filter element is arranged. Alternatively or additionally, the exhaust gas system has two particle filter elements arranged fluidly parallel to one another. The exhaust system is characterized by an adjusting device with which an exhaust gas flow, in particular an exhaust gas mass flow, in the exhaust gas system can be distributed variably to the at least two exhaust gas flows. Alternatively or additionally, the exhaust gas stream, in particular the exhaust gas mass flow, can be distributed variably by means of the adjusting device to the at least two particle filter elements arranged fluidically parallel to one another. With the help of Setting device, it is possible to distribute the exhaust gas flow variable, namely on the at least two exhaust gas flows and / or on the at least two fluidly arranged particle filter elements, wherein by means of the adjusting device a suitable exhaust gas flow on the one hand for efficient heating of the exhaust gas for active regeneration and on the other hand to increase a channel velocity can be set in at least one particulate filter element. Thus, a suitable exhaust gas flow for the ash mobilization and / or for the active regeneration on a particulate filter element can always be set, preferably largely independent of the operating point of an engine that is actively connected to the exhaust system. Particularly preferably, the adjusting device is arranged so that at the same time for a particulate filter element, an exhaust gas flow can be adjusted, which is suitable for efficient heating for active regeneration even at lower heat output and for effective ash mobilization in the particulate filter element.

The adjusting device preferably has at least two functional positions between which it can be switched, in particular two extreme positions, particularly preferably a first functional position, in which at least one exhaust gas flow or at least one particulate filter element is completely blocked, so that no exhaust gas can flow through it /, and a second functional position in which the same particulate filter element or the same exhaust gas flow is completely released in the sense that exhaust gas with a maximum possible flow cross-section can flow through the actuator. The adjusting device preferably has intermediate positions between the at least two functional positions, in particular a plurality of discrete intermediate positions, or preferably a continuum of intermediate positions. The adjusting device is therefore particularly preferably continuously or continuously switchable, in particular between their particular extreme functional positions.

If the adjusting device has at least one adjusting element, this is preferably switchable in an analogous manner to the adjusting device into at least two functional positions, in particular extremal, wherein the at least one actuating element is preferably also switchable in intermediate positions, in particular discretely, preferably steplessly or continuously. This applies particularly preferably to all adjusting elements of the adjusting device.

The adjusting device and / or the at least one adjusting element is / are preferably controllable or controllable, in particular in a controlled or regulated manner in a functional position can be arranged. This preferably applies to all adjusting elements of the adjusting device.

If the exhaust system has at least two particle filter elements arranged fluidly parallel to one another, these are preferably arranged parallel to one another in a common exhaust gas flow. It is then possible, in particular, to release a variable number of particle filter elements to flow through the adjusting device as a function of a total exhaust gas flow through the exhaust gas flow, so that channel velocities are realized in the individual particle filter elements, which is an ash mobilization and thus a transport of wall-deposited ash to a channel end and accordingly a deposition of the ash as a plug-shaped ash - preferably with high bulk density - cause.

If the exhaust system has at least two exhaust gas flows, each with at least one particle filter element, it is in particular possible to throttle the exhaust flow flowing through this flow in favor of the at least one other exhaust gas flow in order to regenerate an exhaust gas flow, thus reducing the exhaust gas flow in the flood to be regenerated to a level in which the entire exhaust gas flowing through the exhaust gas flow to be regenerated can also be heated with a comparatively low heat output, for example of 120 kW, in a manner sufficient for active regeneration. It is then possible, for example, to sequentially regenerate the particle filter elements of different exhaust gas flows in succession, and to distribute the exhaust gas flow in a suitable manner to the various exhaust gas flows by means of the adjusting device. It is possible for a plurality of particulate filter elements to be arranged within an exhaust gas flow, wherein the adjusting device may comprise a plurality of control elements associated with the individual particulate filter elements with which the channel velocity for individual particulate filter elements is sufficient even if the exhaust gas flow through the exhaust gas flow is reduced accordingly for the active regeneration Can be increased so that an ash mobilization is possible. In this case, this can be carried out sequentially by means of the adjusting device for the individual particle filter elements of the same exhaust gas flow. It is also possible in this case, depending on the exhaust gas flow through the exhaust gas flow to flow through a variable number of particulate filter elements to ensure suitable ash rates for ash mobilization.

An exemplary embodiment of the exhaust gas system is preferred in which it has at least two exhaust gas flows, at least two particle filter elements arranged in fluidic parallel relationship being arranged in at least one of the two exhaust gas flows. Particularly preferably, at least two particle filter elements arranged fluidically parallel to one another are arranged in each exhaust gas flow. Particular preference is provided here, that by means of the adjusting device, an exhaust gas flow in the exhaust system can be divided variably both on the at least two exhaust gas flows and on the at least two fluidically arranged parallel particle filter elements. In this respect, in particular a combination of these exemplary embodiments is preferred, so that the features explained below for the two exemplary embodiments are also particularly preferably implemented in combination with one another in an exemplary embodiment of the exhaust system.

By means of the adjusting device, it is preferably also possible to increase the previously throttled exhaust gas flow through an exhaust gas flow, in particular in the case of a sudden load drop of the internal combustion engine and an associated strong decrease in the exhaust gas flow by driving the adjusting device to release the previously throttled exhaust gas flow in this or at least constantly to prevent the soot burn-off reaction in a just-regenerating particulate filter element from passing, and in particular overheating of the particulate filter element and destruction or damage associated therewith.

An embodiment of the exhaust system is preferred, which is characterized in that the adjusting device has at least one adjusting element which is arranged in a common manifold to the at least two fluidly arranged particle filter elements such that a fluid connection to a second particulate filter element of the at least two particulate filter elements the actuator is lockable and releasable, wherein a first particulate filter element of the at least two particulate filter elements is permanently released. In this case, it is possible, in particular, for a comparatively low exhaust gas flow coming from an internal combustion engine, only to flow into the first particulate filter element, and thus to achieve a comparatively high channel velocity, in which an efficient ash immobilization is possible in particular. If the exhaust gas flow through the common manifold increases, the second particle filter element can also be released by means of the at least one control element so that both particle filter elements are flowed through, preferably at a channel velocity suitable for the ash immobilization. In this way, a sufficient channel velocity for efficient ash mobilization can be ensured for the particulate filter elements-particularly preferably independently of the operating point, that is to say in particular independently of an operating point of the internal combustion engine.

It is possible that in the common manifold more than two fluidly arranged parallel particle filter elements and a plurality of actuators are arranged such that - in particular successively - depending on an exhaust gas flow in the common manifold, a variable number of particulate filter elements can be released, so always a sufficiently high channel velocity for the ash mobilization is given in the particle filter elements through which exhaust gas flows. In this case, for example, at a lower exhaust gas flow only a particulate filter element can be flown, wherein at a higher exhaust gas flow, a second particulate filter element is released. With even higher exhaust flow, a third particulate filter element can be released, and so on.

An exemplary embodiment of the exhaust system is preferred, which is characterized in that the at least one actuating element can be blocked and released depending on the operating point. This allows, in particular, a release of particle filter elements arranged fluidly parallel to one another as a function of a currently present exhaust gas flow.

It is possible that the at least one adjusting element is pressure-dependent releasable and lockable. Particularly preferably, the actuating element is biased into a closed position, wherein it is particularly possible that the actuating element has a spring element, by which it is biased in its closed position. The actuator can be designed as a passive valve or as a passive valve. If the exhaust gas flow in the common manifold increases, preferably also a pressure on the actuator increases, so that it is controlled against the biasing force from its closed position to an open position. The further, initially blocked by the actuator particle filter element is then pressure-dependent releasable. It is possible that a series of adjusting elements is arranged one behind the other, which are then sequentially pressure-controlled aufsteuerbar. It is possible that these - seen in the flow direction of the exhaust gas - have an increasing bias, which - again seen in the flow direction - rear locking elements are released only at higher exhaust gas flows than front adjusting elements.

Alternatively or additionally, it is possible for the at least one actuating element to be controllable and in particular controlled or regulated. It may be an active valve device or an active flap. The actuator is preferably discretely or continuously, in particular preferably in intermediate states between a fully open and a fully closed functional position, controllable. Preferably, the actuating element is dependent on an exhaust gas pressure or an exhaust gas flow in the common manifold and / or dependent on an operating point of a cooperating with the exhaust system internal combustion engine controllable, in particular controllable or controllable.

Thus, at least two particulate filter elements are preferably provided in an exhaust gas line or an exhaust gas flow, which are arranged in the exhaust gas line or the exhaust gas flow, so that they can be flowed through by selectively directing the exhaust gas flow either individually or else together. This makes it possible for a defined duration, the space velocity and thus the channel inlet velocity of the exhaust gas, depending on the arrangement of the particulate filter elements and the control elements to increase significantly. This is particularly advantageous for mobilizing ash during particulate filter regeneration.

In a regular operation between two regeneration events, the position of the control elements is preferably such that all particulate filter elements are uniformly flown in order to keep the exhaust gas back pressure for the internal combustion engine at a low level. The steering of the exhaust gas flow is made possible by the use of one or more adjusting elements, which are preferably designed as flaps. Depending on the functional position (s) of the adjusting elements, the exhaust gas flow can be completely or proportionally divided between the particulate filter elements.

The adjusting elements, in particular the flaps, can preferably be arranged upstream or downstream of the particle filter elements.

The setting of the control elements is preferably triggered depending on a loading state of the particulate filter elements with soot and / or ash, and / or in response to an operating condition of an internal combustion engine, which cooperates with the exhaust system, in particular controlled or regulated. At the same time or offset in time, before or after, the Rußabbrand is triggered in the one or more then traversed particulate filter elements. The loading state can be determined, for example, by a sensor or by a model. If the regeneration of the soot of the particle filter elements through which flowed through and the associated mobilization of ash due to the control of the control elements were successfully completed, they are controlled or controlled so that exhaust gas flows through another exhaust gas flow or other particulate filter elements and the described process is there can be repeated. The triggering of the control of the control elements and the associated regeneration of particulate filter elements is preferably carried out at an advantageous for the ash immobilization operating state of the internal combustion engine and / or at a corresponding loading state of ash and / or soot of an affected particulate filter element.

By increasing the channel inlet velocity and by selectively directing the exhaust gas flow to a part of the installed particulate filter elements, the density of the ash mobilized during the particle filter regeneration increases in comparison to an exhaust system without corresponding adjusting device, with otherwise identical boundary conditions. This reduces the volume of ashes deposited as stoppers, the density of which increases accordingly, which means that the interval between cleaning the particulate filter elements of ash can be extended. Furthermore, the control of the adjusting device allows an expansion of the operating range of the internal combustion engine, in which the ash can be successfully mobilized during a particulate filter regeneration, to smaller loads, in particular to loads less than 30% of a rated load. Furthermore, due to the increase of the channel velocity by the activation of the adjusting device, the soot loading necessary for the ash immobilization may be lower before the particle filter regeneration. As a result, the back pressure resulting from the soot deposition can be kept lower. In addition, the risk of a strong increase in temperature in the particulate filter during uncontrolled Rußabbrands, which can lead to destruction of particulate filter substrates, especially because the actuator at a sudden load and thus waste gas flow in the engine can control a flow cross-section for a just regenerating particulate filter element.

In order to improve an ash deposition characteristic - preferably as a tight plug ash at the ends of the channels - it is therefore proposed to use a plurality of particle filter elements, these being flowed through depending on the operating point. For low load operating points, not all particulate filter elements should be flown to increase the channel velocities of the respective particulate filter elements, even at low load points. Such a register arrangement can be realized, for example, via flaps, which can be controlled autonomously, without external regulation, via the pressure level upstream of the particle filter elements. The pressure level upstream of the particle filter elements adjusts in particular as a function of the volume flow. When increasing the volume flow as an opening of the mechanical flaps by the increased pressure level can be realized. Optionally, an external, for example, electronically controlled movement of the flaps from the control unit of the internal combustion engine out. The register arrangement and flow of the particulate filter elements allows an increase in the flow velocities, especially for low load points, so regardless of Load profile of the engine a counter pressure, denser ash deposition can be achieved at the channel end. This could make it possible to extend the intervals of the active regeneration or to achieve an increase in the ash release intervals during passive regeneration.

An exemplary embodiment of the exhaust system is also preferred, which is characterized in that the adjusting device has at least one first adjusting element with which the exhaust gas flow can be distributed variably to the at least two exhaust gas floods. The at least one first control element is preferably controllable operating point dependent. By means of the first control element, it is then possible to divide the exhaust gas, in particular depending on a current total exhaust gas flow, either evenly or at different proportions to the different exhaust gas flows, in particular to ensure sufficient heating of the exhaust gas for active regeneration, and / or to ensure a sufficient channel velocity in a particulate filter element for efficient ash mobilization. The at least one adjusting element is preferably designed as a flap.

An exemplary embodiment of the exhaust system is preferred in that at least one exhaust gas flow has at least two particle filter elements, wherein the control device has a plurality of second control elements in the at least one exhaust gas flow, each second control element being exactly one particle filter element or a group of particle filter elements of the exhaust gas flow assigned. In this way it is possible, within the at least one exhaust gas flow by means of the at least one second control element, the exhaust gas flow to the at least two particulate filter elements, which are preferably arranged fluidly parallel to each other. In this way, it is always possible to ensure a sufficient channel velocity in a particle filter element for efficient ash immobilization within an exhaust gas flow. Depending on the exhaust gas flow in the exhaust gas flow, in particular more or fewer particle filter elements can then be blocked or released in order to ensure a minimum channel velocity in the particle filter elements, in particular for the purpose of efficient ash mobilization. The at least one second control element is preferably designed as a flap. It can be arranged directly in front of or directly behind a particle filter element assigned to it. Particularly preferably, each particle filter element is associated with a second control element, more preferably, such an actuating element is arranged in front of each particle filter element or behind each particle filter element.

In a preferred embodiment, it is provided that each exhaust gas flow of the exhaust system comprises at least two particulate filter elements, wherein the adjusting device comprises a plurality of second control elements in each exhaust gas flow, each second control element being associated with exactly one particulate filter element or one group of particulate filter elements of the exhaust gas flow. In this case, the aforementioned advantages are realized not only in a selection of exhaust gas flows, but in each exhaust gas flow of the exhaust system.

An exemplary embodiment of the exhaust system is preferred, which is characterized in that the second control elements can be actuated as a function of the operating point. In this case, it is possible, in particular, for these to be actuated as a function of pressure, in particular as a function of an exhaust gas pressure in an exhaust gas flow, to which the second control elements are assigned, and / or depending on an operating state of an internal combustion engine in combination with which the exhaust gas system is used. be controlled. It is also possible for an exhaust gas flow to be detected directly by an exhaust gas flow, wherein the second control elements arranged in the exhaust gas flow are activated as a function of the detected exhaust gas flow. Thus, it is always possible to control the second control elements, in particular to control their control positions or to regulate that sets in a particulate filter element or in a plurality of particulate filter elements sufficient for the purpose of ash mobilization channel velocity.

An exemplary embodiment of the exhaust system is also preferred, which is characterized in that each exhaust gas flow is assigned a separate heating element for the active regeneration of the particulate filter elements. This has the advantage that the heating elements-which may be preferably designed as burners or as electrical heating elements-each individually can be made smaller than if the entire exhaust gas stream had to be heated upstream of a distribution to the various exhaust gas flows. In addition, with the aid of the at least one first control element of the control device, it is preferably possible to reduce the exhaust gas flow through an exhaust gas flow, in which an active regeneration is to be carried out, so that the heating power of a smaller heating element, in particular a maximum heat output of 120 kW, is sufficient to heat the exhaust gas in the exhaust gas flow for the purpose of successful active regeneration. This results in a synergistic effect between the assignment of a heating element to a single exhaust gas on the one hand and the adjusting device on the other hand, which allows to dimension the individual heating elements again smaller. It is thus particularly possible, even for larger internal combustion engines with higher nominal power, especially for use in commercial vehicles, to drive harder Motor vehicles such as trains, construction machinery, mine vehicles, stationary operation, in the extraction of raw materials, in the industrial and construction sector, or used for power generation, also to use heating elements, which are actually in the field of road vehicles, especially for the passenger car or truck Are designed and correspondingly have smaller heating capacities, in particular up to 120 kW.

An embodiment of the exhaust system is also preferred, which is characterized in that the adjusting device is switchable in at least two different operating modes, wherein the at least two different modes are selected from a group consisting of a normal operation, a pure ash mobilization operation, a pure soot regeneration operation, a combined soot regeneration and ash mobilization operation, and a protection operation.

In this case, a normal operation is also understood to mean regular operation of the exhaust system and in particular also an internal combustion engine in which neither ash mobilization nor soot regeneration is carried out, and insofar no special protective measures are provided for the exhaust system and in particular for particulate filter elements included therein are meeting.

A pure ash mobilization operation is understood to mean a mode in which no soot regeneration is carried out, but a channel velocity is set exclusively in the particle filter elements, as a result of which ash deposited on channel walls is transported to the end of the channel and / or compressed at the end of the channel.

A pure soot regeneration operation is understood as an operating mode in which soot regeneration, in particular active soot regeneration, of a particle filter element takes place without ash being mobilized at the same time. This can be achieved in particular by an increase in the exhaust gas temperature while at the same time falling below a minimum channel velocity necessary for the ash immobilization in the particle filter element.

Preferably, the pure ash mobilization operation follows a previously performed, pure soot regeneration operation. In particular, it is possible for a soot regeneration to be carried out first, in particular under any boundary conditions, after which ash is mobilized in a targeted manner. In fact, ash mobilization can be carried out particularly effectively either in combination with soot regeneration or in direct, temporally direct connection with previously occurring soot regeneration.

A combined soot regeneration and ash mobilization operation is understood as an operating mode in which a particulate filter element is simultaneously regenerated, in particular actively regenerated, whereby ash deposited at the same time on channel walls is mobilized and transported at channel ends and / or compacted there. So there is a combined Rußabbrand with ash mobilization. This mode of operation is particularly favorable, because the ash mobilization takes place particularly efficiently if at the same time a Rußabbrand takes place.

A protective operation is understood to be a mode in which a particulate filter element of the exhaust system is protected against overheating or thermal damage, for example in the event of a sudden drop in load of an internal combustion engine assigned to the exhaust system. If, for example, an active regeneration is carried out in a particulate filter element at a certain load point of an internal combustion engine and then a sudden load drop occurs, the exhaust gas mass flow typically drops abruptly through the particulate filter element. Thus, at the same time, the heat discharged from the particulate filter element per unit of time with the exhaust gas flowing through suddenly abruptly decreases. However, the Rußabbrandreaktion in the particulate filter element does not spontaneously come to a halt, but rather continues, with the resulting heat so far can not be effectively dissipated. It then threatens damage to the destruction of the particulate filter element by overheating. In the protective mode, in such a case, the particulate filter element is preferably supplied with increased exhaust gas mass flow again by suitable actuation of the adjusting device, in particular by increasing the exhaust gas mass flow through the particulate filter element concerned to the disadvantage of the exhaust gas mass flow through other particulate filter elements and / or exhaust gas flooding, in particular abruptly. In particular, when the exhaust gas stream for the purpose of efficient heating of the exhaust gas for the path through the particulate filter element was first throttled, now very quickly additional exhaust gas flow through the particulate filter element can be released so that the exhaust flow through the particulate filter element concerned preferably kept constant or at least its waste can be avoided under a critical for the destruction of the particulate filter element limit. It can thus be ensured that always sufficient heat is removed from the particulate filter element, so that it remains protected from damage or destruction.

For normal operation, the adjusting device is preferably so controlled that the exhaust gas flow is evenly divided among the various exhaust gas flows and / or particulate filter elements. For a pure ash mobilization operation, the exhaust gas flow through a selected particulate filter element or a selected group of particulate filter elements is preferably increased, so that in this / this there is sufficient channel velocity for the ash mobilization. For a pure Rußregenerationsbetrieb preferably the exhaust gas flow is throttled by an exhaust gas flow and / or a particulate filter element to allow efficient heating of the exhaust gas, even with relatively low heat output. For a combined soot regeneration and ash mobilization operation, at least one first control element of the control device is preferably activated such that an exhaust gas flow through an exhaust gas flow is throttled for the purpose of efficient heating of the entire exhaust gas even at low heat output of a heating element associated with the exhaust gas flow, at least by controlling at least a second control element for at least one particulate filter element of this exhaust gas flow is ensured that in the particulate filter element nevertheless a sufficiently high channel velocity for ash mobilization prevails. For protection operation, the adjusting device is controlled so that the exhaust gas flow through a just regenerating particulate filter element - especially abruptly - is increased in order to avoid overheating, thermal damage or destruction.

The invention also includes in this context a method for operating an exhaust system according to one of the embodiments described above, and / or a combination of an internal combustion engine with such an exhaust system, wherein the adjusting device is driven in a normal operation to evenly distribute an exhaust gas flow to a plurality of Split exhaust gas and / or a plurality of particulate filter elements. It is preferably provided that the adjusting device is controlled in a pure ash-mobilizing operation in such a way that the exhaust gas flow through at least one particle filter element is increased at the expense of at least one other particle filter element and / or at least one other exhaust gas flow. Preferably, the adjusting device is controlled in a pure Rußregenerationsbetrieb so that the exhaust stream is reduced by at least one exhaust gas flow and / or at least one particulate filter element in favor of at least one other exhaust gas flow and / or at least one other particulate filter element. Preferably, the actuator is controlled in a combined Rußregenerations- and ash mobilization so that the exhaust stream is reduced by at least one exhaust gas flow in favor of at least one other exhaust gas flow, at the same time increases the exhaust gas flow through an active regenerating particulate filter element of this one exhaust gas at the expense of at least one other particulate filter element same exhaust gas flow becomes. Preferably, the adjusting device is controlled in a protective operation so that the exhaust gas flow is increased by an actively regenerating particulate filter element - in comparison to the previous Rußregenerationsbetrieb -.

With regard to the exhaust system according to the invention, in particular the following is shown: At least two exhaust gas flows are provided, via which the exhaust gas is guided. Each flood is equipped with at least one particle filter element, through which the exhaust gas to be purified can flow. By targeted steering of the exhaust gas flow, the exhaust gas flows and / or the individual particle filter elements are flowed through either individually, proportionally or else evenly.

Depending on the number of exhaust gas flows provided, the steering of the exhaust gas flow is made possible by the use of the adjusting device, in particular by the use of one or more flaps. The adjusting device and in particular its adjusting elements, preferably flaps, can / can be continuously adjusted so that any portions of the exhaust gas stream can be directed to the individual exhaust gas flows. As a result, just as many exhaust gas masses can be directed to an exhaust gas flow that the heating power for an active soot regeneration with a favorable heating element developed for the on-road area is sufficient for soot loading in the entire operating map of an internal combustion engine which is operated together with the exhaust system the particulate filter elements safely controlled by this exhaust flow or control. It is now provided for each exhaust gas, the use of such derived from the automotive sector system for active regeneration. If the process of active regeneration for an exhaust gas flow is completed, the adjusting device, in particular its adjusting elements, is set such that the next exhaust gas flow receives exactly the same amount of exhaust gas that the heating power of a heating element taken over from the motor vehicle area is sufficient for the active regeneration is. If there are further exhaust gas flows, the process is repeated until all the exhaust gas floods have been successfully regenerated. At the same time, when an exhaust gas flow is actively regenerated, the other exhaust gas flows / flows are / are traversed by the remaining exhaust gas mass so that it is always ensured that soot is filtered out of the exhaust gas.

The exhaust gas stream can preferably be divided not only deliberately proportionately to individual exhaust gas flows, but also targeted by individual or more particulate filter elements of the same exhaust gas flow steer, which is currently actively regenerated. This is achieved by arranging second control elements, in particular further flaps, before or after each particle filter element of each exhaust gas flow. If a plurality of particulate filter elements are present in an exhaust gas flow that is actively regenerating at this time, the exhaust gas flow can be controlled by a suitable control of the second control elements by a single particulate filter element, and raised relative to a simultaneous flow through a plurality of particulate filter elements. As a result, the channel inlet velocity of the exhaust gas in the actively regenerated particulate filter element also multiplies in the same way, which has an advantageous effect on the mobilization and deposition of ash in the inlet channels, which was separated together with the soot between two active regeneration processes. In the case of active regeneration of one or more particulate filter elements of an exhaust gas flow, the process of corresponding control of the second control elements for all further particulate filter elements of this flood is continued until all particulate filter elements of this flood have been regenerated in the same way. Following this, the further exhaust gas flows are actively regenerated in the same way.

Where reference is made here, in the foregoing and in the following to an order for the active regeneration and / or the ash mobilization with regard to individual or also a plurality of particulate filter elements, it is emphasized that this order is by no means absolutely mandatory. In particular, it is not absolutely necessary that first all the particle filter elements of an exhaust gas flow are treated, after which particle filter elements of another exhaust gas flow are treated. Rather, it is also possible that, for example, particulate filter elements of different exhaust gas flows are treated alternately, and / or that just needs a treatment of different particulate filter elements successively - regardless of their arrangement in a specific exhaust gas flow - takes place. In particular, any sequence in the treatment of the particle filter elements or even groups of particle filter elements is always possible.

In regular operation between two regenerations, the position of the adjusting device, in particular its adjusting elements, is set so that the most optimal operating state is established. All the exhaust gas flows and particle filter elements can be flowed through uniformly, in particular in order to keep the exhaust backpressure for the internal combustion engine at a low level and to load the particle filter elements uniformly with soot. Likewise, however, the flow through individual exhaust gas flows and / or particulate filter elements can also be increased in a targeted manner, for example, in order to more quickly deposit a filtration-effective soot cake after an active regeneration.

In that regard, a deposition operation for the actuator is preferred in which it is controlled so that the exhaust stream is increased by an exhaust gas flow and / or by a particulate filter element at the expense of another exhaust gas flow or other particulate filter element to amplified in the increasingly flowed particulate filter element or streamed exhaust gas flow to separate a filtration effective carbon black cake.

The actuating position of the actuating device required for the active regeneration is preferably controlled or controlled in order to direct the corresponding exhaust gas mass to an exhaust gas flow which is still suitable for successfully regenerating with a heating element taken over from the on-road or motor vehicle sector in the entire engine map , This can be done by using suitable sensors, models or maps.

The required for the ash immobilization position of the actuator for the particulate filter elements of the exhaust gas to be actively regenerated is preferably controlled or controlled to direct the corresponding exhaust mass to one or more particulate filter elements, which is suitable for the ash mobilization sufficiently high channel inlet velocity to reach. This can be done by using suitable sensors, models or maps.

The setting of the adjusting device is preferably triggered and controlled or regulated as a function of a loading state of the particulate filter elements with soot and / or an operating state of the internal combustion engine. Simultaneously or temporally offset before or after the Rußabbrand is triggered by active regeneration in the then flowed through the particulate filter element (s).

The soot loading condition can be determined, for example, by a sensor or a model.

If the regeneration of flow-through particle filter elements of an exhaust gas flow has been successfully completed due to the control of the control device, the control device is preferably regulated or controlled so that exhaust gas flows through at least one further exhaust gas flow, wherein the described process can be repeated there.

The presence of the adjusting device for targeted steering of the exhaust gas flow between individual exhaust gas flows and / or individual particle filter elements can also be used for control or regulation the desired exhaust gas temperature during an active regeneration of one or more particulate filter elements are used. By increasing or decreasing the exhaust gas mass through an exhaust gas flow or individual particle filter elements, the exhaust gas inlet temperature can be reduced or increased while the heat output of the system for active regeneration from the motor vehicle area remains the same. This is of great advantage, in particular in the case of a load drop, in particular a so-called "drop-to-idle process", in order to protect particulate filter elements from unfavorably high component temperatures or temperature gradients if they are close to a soot load at the beginning of active soot regeneration Soot Mass Limit (SML) load. If, for example, at full load only a small proportion of the exhaust gas mass, for example in the range between 10% and 20%, is directed to an exhaust gas flow and the active regeneration started there, in the event of a load shedding to idle at the same position of the adjusting device, temperatures may become just active Regenerated particulate filter elements occur that can lead to their damage. Due to the significantly lower exhaust gas mass, which flows at idle at the same position of the actuator through the just regenerated particulate filter elements, the reaction enthalpy occurring can no longer be dissipated, even if the heating power of the system for active regeneration is turned off. If, however, by suitable regulation or control of the adjusting device, the predominant or total proportion of the exhaust gas mass at idling is directed to the exhaust gas flow or individual particle filter elements of this exhaust gas flow which has just been actively regenerated (n), then the exhaust gas mass through these particle filter elements is comparable to that Starting the active regeneration at full load and thus sufficient to successfully dissipate the heat of reaction, even if the heating power of the system for active regeneration has not been turned off yet. By doing so, the risk of waste load for the particulate filter elements having soot loadings near or above the peak soot loading can be substantially reduced, and soot loading strategies can be realized which are beneficial to the operation of the particulate filter elements and require loads near and possibly even above the bench top load.

Thanks to the adjusting device, it is possible in applications for which an active regeneration of particulate filter elements is absolutely necessary to resort to systems that are in medium duty or heavy duty applications, especially in the on-road commercial vehicle sector, for years in use. These are generally much less expensive, have a very high technological maturity and a smaller footprint for installation, as available on the market today systems that are offered for high performance classes beyond such on-road applications. Furthermore, the supply of such systems in the market is much more diverse.

In addition, an active regeneration can be initiated in a significantly wider map range, since the exhaust gas flow for the regeneration of a single particulate filter element in a wider range of the map is applied, as would be the case with a simultaneous regeneration of the entire system. For some applications that have load profiles with a pronounced low load, the window of opportunity for successful active regeneration will increase significantly. The "Zulaufen" of particulate filters due to excessive soot loading, and consequently the shutdown of the engine and a manual filter cleaning, or alternatively disrupting the operation stoppage regeneration are prevented.

Furthermore, by suitably setting the adjusting device at the time of active regeneration, a channel inlet velocity for at least one particulate filter element can be set specifically, which is advantageous for ash mobilization and thus enables a prolonged service life of the particulate filter elements. Further, the risk of critical component temperatures or gradients in the case of load dumping at soot loadings near or above the limit bucket load can be reduced by suitable actuation of the actuator, particularly in the guard mode.

The object is also achieved by providing an internal combustion engine having an exhaust system according to one of the previously described embodiments. In connection with the internal combustion engine, in particular, the advantages that have already been explained in connection with the exhaust system arise.

An embodiment of the internal combustion engine is preferred, which is characterized in that the control device of the exhaust system and / or a control device of the internal combustion engine, which is used as a control device of the exhaust system, is arranged for detecting an operating point of the internal combustion engine and / or a loading of at least two Particulate filter elements with soot and / or ash, as well as for controlling the adjusting device in dependence on the operating point of the internal combustion engine and / or the loading of the particulate filter elements with soot and / or ash. Thus, an always suitable control of the adjusting device for the distribution of the exhaust gas flow, in particular for the purpose of sufficient heating of the exhaust gas for active regeneration of particulate filter elements and / or to ensure a sufficient channel velocity in at least one Particle filter element for efficient ash mobilization, be ensured.

Preferably, a central control unit of the internal combustion engine, in particular an engine control unit (ECU) is used as a control device of the exhaust system, or the functionality of the control device of the exhaust system is implemented in the central control unit of the internal combustion engine.

The internal combustion engine is preferably designed as a reciprocating engine. It is possible that the internal combustion engine is arranged to drive a passenger car, a truck or a commercial vehicle. In a preferred embodiment, the internal combustion engine is used to drive in particular heavy land or water vehicles, such as mine vehicles, trains, the internal combustion engine is used in a locomotive or a railcar, or ships. It is also possible to use the internal combustion engine to drive a defense vehicle, for example a tank. An exemplary embodiment of the internal combustion engine is preferably also stationary, for example, used for stationary power supply in emergency operation, continuous load operation or peak load operation, the internal combustion engine in this case preferably drives a generator. A stationary application of the internal combustion engine for driving auxiliary equipment, such as fire pumps on oil rigs, is possible. Furthermore, an application of the internal combustion engine in the field of promoting fossil raw materials and in particular fuels, for example oil and / or gas, possible. It is also possible to use the internal combustion engine in the industrial sector or in the field of construction, for example in a construction or construction machine, for example in a crane or an excavator. The internal combustion engine is preferably designed as a diesel engine, as a gasoline engine, as a gas engine for operation with natural gas, biogas, special gas or another suitable gas. In particular, when the internal combustion engine is designed as a gas engine, it is suitable for use in a cogeneration plant for stationary power generation.

The invention will be explained in more detail below with reference to the drawing. Showing:

1 a schematic representation of a first embodiment of an internal combustion engine with a first embodiment of an exhaust system;

2 a schematic, diagrammatic representation of the dependence of the type of ash deposition in a particulate filter element of an engine load or channel velocity and the soot load in the particulate filter element at the time of soot regeneration;

3 a schematic representation of a second embodiment of an exhaust system in a first mode;

4 the second embodiment of the exhaust system according to 3 in a second mode;

5 a schematic representation of a third embodiment of an exhaust system in a first mode;

6 the exhaust system according to 5 in a second mode;

7 the exhaust system according to the 5 and 6 in a third mode, and

8th the exhaust system according to the 5 to 7 in a fourth mode.

1 shows a schematic representation of an embodiment of an internal combustion engine 1 which is an exhaust system 3 according to a first embodiment. The internal combustion engine 1 also has an engine block 5 on, being out of the engine block 5 effluent exhaust gas through the exhaust system 3 to be led.

The exhaust system 3 has at least two - in particular three or more fluidly arranged parallel to each other particle filter elements 7 , here are three particulate filter elements 7.1 . 7.2 . 7.3 , on. It is an adjusting device 9 provided with the exhaust gas flow, in particular an exhaust gas mass flow, in the exhaust system 3 variable on the particulate filter elements 7.1 . 7.2 . 7.3 is divisible.

The adjusting device has a plurality of adjusting elements 11 , in particular two designed as valves actuating elements 11.1 . 11.2 on that in a common manifold 13 to the fluidically parallel particle filter elements 7.1 . 7.2 . 7.3 are arranged such that a fluid connection to a second particulate filter element 7 , here for example to the second and third particle filter elements 7.2 . 7.3 , the at least two particulate filter elements 7 through the control elements 11.1 . 11.2 lockable and releasable, wherein a first particulate filter element 7.1 the particulate filter elements 7 permanently released. Here are the control elements 11 In particular, depending on operating point lockable and releasable. In the embodiment shown here are the control elements 11 pressure-dependent lockable and releasable. They are in particular by spring elements 15 in a biased closed position, being dependent on one on the control elements 11 open acting exhaust gas pressure. Thus, at an operating point of the internal combustion engine 1 with low load not all particulate filter elements 7 flows, so that the channel velocities of the impinged particulate filter elements 7 are also increased in low load points. Overall, such a register arrangement of particle filter elements 7 realized, in which case the adjusting device 9 about the pressure level in the common manifold 13 autonomous and can be controlled without external control. This pressure level adjusts in particular volume flow dependent. When increasing the exhaust gas flow, in particular the exhaust gas volume flow or the exhaust gas mass flow, so is an opening of the control elements 11.1 . 11.2 realized by the increased pressure level. It is possible that different control elements 11.1 . 11.2 , which are in particular - viewed in the flow direction of the exhaust gas - arranged one behind the other, different bias voltages are assigned. In this case, in particular - seen in the flow direction of the exhaust gas - front actuators 11.1 preferably associated with a lower bias, as seen in the flow direction following actuators 11.2 , This can be done in particular by different, the different control elements 11.1 . 11.2 associated spring elements 15.1 . 15.2 will be realized. It can be ensured in a particularly favorable manner that with increasing exhaust gas flow an increasing number of particle filter elements is released.

Alternatively to the embodiment of the adjusting device shown here 9 It is also possible that this is actively controlled or regulated, it may be formed in particular as a valve device and / or as an active flap system. In particular, there is an external, electronically controlled movement of the control elements 11.1 . 11.2 from a control device, in particular a control unit of the internal combustion engine 1 out of question.

In the 1 shown register arrangement and flow of the particulate filter elements 7 allows an increase in flow velocities, especially for low load points, so that regardless of the load profile of the internal combustion engine 1 a low-pressure, denser ash deposition can be achieved at the channel ends of the particulate filter elements. This makes it possible to set the intervals for active regeneration of the particulate filter elements 7 to prolong or passivate regeneration to extend the ash cleaning intervals.

2 shows a schematic, diagrammatic representation of a dependence of a type of ash deposition in a particulate filter element of the engine load or a channel velocity, in particular channel inlet velocity, and the soot load in a particulate filter element at the time of soot regeneration. Plotted on the horizontal axis is, on the one hand, a relative engine load ML and a relative channel speed, in particular a relative channel entry speed, KG. The scales of the horizontal axes are normalized to a maximum value and thus range from 0% to 100%. On the vertical axis, a soot loading R of the particulate filter element under consideration is removed. A first limit curve K1 schematically indicates the limit of soot loading R up to which the probability of forming a wall deposit of ash is very high. This area is also schematically denoted by I here. A second limit curve K2 schematically shows the limit of the soot loading R at which the probability of forming a plug deposit of ash is very high. The corresponding area is designated III. Between the first limit curve K1 and the second limit curve K2 there is an area denoted by II, in which the probability of formation of mixed forms of the ash deposit is high. With a relative engine load ML of less than 30%, these limits are not clearly known, but the probability is very high that the ash can not be mobilized and deposits in the form of a wall deposit. With a horizontal line H is a Grenzrußbelung SML (soot mass limit) shown, from which when exceeding the Grenzrußbeladung the risk of destruction of the particulate filter elements due to uncontrolled Rußabbrands and associated high temperatures rises sharply.

Above the limit curve K2 to plug formation, there is a dependence of the ash density of the plug formed by the relative engine load ML, respectively, the relative channel velocity KG and the soot charge R at the time of soot regeneration, wherein here schematically different density areas of the bottom left to the top right of increasing density ρ ₁ , ρ ₂ , ρ ₃ , ρ ₄ , wherein the first density ρ _{1 is} smaller than the second density ρ ₂ , wherein the third density ρ _{3 is} greater than the second density ρ ₂ , and wherein the fourth density ρ ₄ again larger than the third density ρ ₃ .

2 also shows schematically the effect of driving the actuator 9 to increase the ash density. For example, the internal combustion engine 1 operated at 50% load at the time of regeneration of the particulate filter element for the purpose of ash mobilization, the particulate filter element must have a soot loading R near the Grenzrußbeladung SML prior to regeneration, so that the ash can be successfully mobilized and deposited as a plug at the end of the filter channels. If the particulate filter element without Operated activation of the adjusting device, the ash would be deposited as a stopper with a 50% density ρ _50% at the end of the channel after regeneration. This relationship is shown here by a first arrow P1.

In contrast, the exhaust gas flow at 50% load of the internal combustion engine 1 For example, instead of only two exhaust gas flows directed to an exhaust gas flow, or directed instead of two particulate filter elements only on a particulate filter element, so doubles the relative channel velocity of the traversed exhaust gas flow or the traversed particulate filter element from previously 50% to 100%, without that at the Motor load changes something, which is shown here by a second arrow P2. It follows that - with the same soot loading before regeneration - the ash after the regeneration with a higher 100% density ρ _{100% is} deposited at the end of the channel.

Accordingly is off 2 Also read that in the case in which the internal combustion engine 1 operated at 30% load at the time of regeneration of the particulate filter element, which is loaded with soot below the Grenzrußbeladung SML, there is a high risk that the ash is not mobilized in the regeneration and is deposited as wall deposition or as a mixture of wall deposition and plug deposition , This is disadvantageous for a long service life of the particulate filter element. However, if, for example, the exhaust gas flow is directed by means of the adjusting device at 25% load from two exhaust gas flows or two particle filter elements to only one exhaust gas flow or only one particle filter element, the relative duct speed doubles from previously 25% to now 50%. This in turn means that with constant soot loading prior to regeneration, the ash can be mobilized by the regeneration and is now deposited as a plug with a density of ρ _{50% again} at the end of the channel without any change in the engine load.

It can also be seen that in the case where an internal combustion engine is operated at 50% load at the time of regeneration of the particulate filter element, it must be loaded with at least _50% soot so that the ash can be successfully mobilized and deposited as a plug. From this amount of soot R _50% results in a back pressure over the particulate filter, which is for example referred to as dp _50% . If now the exhaust gas flow by means of the adjusting device of two exhaust gas flows or two particle filter elements only directed to an exhaust gas flow or only a particulate filter element, so again doubles the relative channel velocity of previously 50% to 100%, without changing the engine load something. It follows that for a successful mobilization of the ashes during regeneration, the particulate filter element must be loaded before regeneration only with the lower soot loading R _100% . The only necessary for the mobilization, lower soot loading R _100% then results in a lower back pressure, which can be referred to as dp _100% , for example, which is advantageous for fuel consumption.

3 shows a schematic representation of a second embodiment of the exhaust system 3 , Identical and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description. The exhaust system 3 has here two exhaust gas flows, namely a first exhaust gas flow 17 and a second exhaust gas flow 19 , By means of the adjusting device 9 in this embodiment is an exhaust gas flow in the exhaust system 3 variable on the exhaust gas flows 17 . 19 divisible. The adjusting device 9 here has a first actuator 21 on, with the exhaust gas flow variable to the exhaust gas 17 . 19 can be divided, wherein the first actuating element 21 Operating point dependent by a control device 23 is controllable. For this purpose, the control device 23 in particular with the first actuating element 21 operatively connected.

It is possible that the control device 23 as a central control unit of the internal combustion engine 1 is trained. The control device 23 is preferably configured to detect an operating point of the internal combustion engine 1 and / or a soot loading of at least one particulate filter element 7 , as well as for controlling the adjusting device 9 as a function of the operating point of the internal combustion engine 1 and / or depending on the soot loading of the at least one particulate filter element 7 , For this purpose, a suitable sensor system and / or suitable algorithms are / are preferably provided.

Each of the exhaust fumes 17 . 19 here has a plurality of particulate filter elements 7 on, in particular four particle filter elements per exhaust gas flow 17 . 19 ,

In the specific embodiment shown, the exhaust system 3 an exhaust gas inlet 25 on, here specifically coming from two cylinder banks exhaust gas in a manifold 27 is merged. In the manifold 27 is a divider 29 arranged, through which the exhaust gas flows 17 . 19 be separated from each other. The adjusting device 9 and in particular the actuator 21 is so in the manifold 27 arranged that the combined exhaust gas flow variable to the exhaust gas flows 17 . 19 is divisible.

Each of the exhaust fumes 17 . 19 is in each case an exhaust gas outlet 31 assigned. The actuator 21 is preferably infinitely adjustable. Independently from a current position of the actuator 21 the exhaust gas is always passed over at least one particulate filter element and cleaned of particles. In 3 is the second embodiment of the exhaust system 3 in a first mode, namely a normal operation shown, in which the exhaust gas flows 17 . 19 Evenly, so in particular in equal parts, to be flowed through with exhaust gas.

4 shows the second embodiment of the exhaust system 3 according to 3 in a second mode, namely a combined ash mobilization and soot regeneration operation for the first exhaust gas flow 17 , Identical and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description. The actuator 21 closes here the second exhaust gas flow 19 completely, so that the entire exhaust gas through the first exhaust gas flow 17 flows. This doubles the channel velocity in the particulate filter elements 7 the first exhaust gas flow 17 compared to the in 3 Normal operation shown, which - as previously in connection with 2 explained - advantageous for the mobilization and plugging of the ash during the particle filter regeneration of the particulate filter elements 7 is.

In a completely analogous way, it is possible that - preferably after completion of the regeneration of the particulate filter elements 7 the first exhaust gas flow 17 - The actuator 21 is brought into a functional position in which it is the first exhaust gas flow 17 completely closes, so that now the entire exhaust gas through the second exhaust gas flow 19 flows. The channel velocity doubles in the particle filter elements 7 the second flood 19 in comparison to the normal operation according to 3 , which in turn is beneficial for the mobilization and plugging of the ash during particulate filter regeneration.

5 shows a schematic representation of a third embodiment of the exhaust system 3 , Identical and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description. In this embodiment, each exhaust gas flow 17 . 19 in each case a plurality of particle filter elements 7 on, specifically here the first exhaust gas flow 17 four particulate filter elements 7.1 . 7.2 . 7.3 . 7.4 , and the second exhaust tide 19 four particulate filter elements 7.5 . 7.6 . 7.7 . 7.8 , wherein the adjusting device 9 - in addition to that already in connection with the 3 and 4 explained first actuator 21 - A plurality of second control elements 33 each second actuator 33 exactly one particle filter element 7 assigned. So are in the first exhaust tide 17 the second control elements 33.1 . 33.2 . 33.3 . 33.4 each corresponding to the numbered particle filter elements 7.1 . 7.2 . 7.3 . 7.4 assigned, wherein in the second exhaust gas flow 19 the control elements 33.5 . 33.6 . 33.7 . 33.8 the correspondingly numbered particle filter elements 7.5 . 7.6 . 7.7 . 7.8 assigned. The second control elements 33 are here immediately upstream of their associated particulate filter elements 7 arranged. It is alternatively also possible that the control elements 33 immediately downstream of their associated particulate filter elements 7 are arranged.

It is important that with the second control elements 33 in each case the individual particle filter elements 7 that are assigned to them, are individually lockable and releasable.

The second control elements 33 are preferably designed as butterfly valves. The second control elements 33 are in particular operating point-dependent, preferably dependent on an operating point of the internal combustion engine 1 and / or from an exhaust gas mass flow or an exhaust gas volume flow through the exhaust system 3 controllable.

In 5 also shows that every exhaust tide 17 . 19 a separate heating element for active regeneration of the particulate filter elements 7 is assigned, namely the first exhaust gas flow 17 a first heating element 35 and the second exhaust gas flow 19 a second heating element 37 ,

5 shows the third embodiment of the exhaust system 3 in a first mode, namely in normal operation. Here is the first control element 21 preferably placed so that the exhaust gas evenly on the exhaust gas 17 . 19 is distributed. The second control elements 33 are preferably all arranged in their open position, so that the particulate filter elements 7 all are flowed evenly with exhaust gas. In normal operation, neither of the two heating elements 35 . 37 active, and there is no soot regeneration.

6 shows the third embodiment of the exhaust system 3 according to 5 in a second mode, namely in a pure soot regeneration mode. Specifically shows 6 a pure Rußregenerationsbetrieb for the first exhaust gas flow 17 , Identical and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description. The first control element 21 is arranged here in a functional position, in which the exhaust gas predominantly by the second exhaust gas flow 19 flows, with a reduced or throttled exhaust gas flow over the first exhaust gas flow 17 is realized, for example, of 15% based on full load. The first heating element 35 is active while the second heating element 37 is inactive. The position of the first control element 21 is chosen so that only so much exhaust gas through the first exhaust gas flow 17 that flows the heating power of the first heating element 35 to the active one Regeneration of the particle filter elements 7 in the first tide 17 sufficient, in particular a heating element 35 with lower heating power than would be necessary for a successful heating of the unthrottled exhaust gas flow, for example of 120 kW, whereby nevertheless a desired target temperature for successful combustion of soot into the exhaust gas flow is due to the reduced exhaust gas flow 17 associated particulate filter elements 7 is reachable. By targeted activation of the first control element 21 and thus a regulation or control of the exhaust mass in the first flood 17 it is possible, the soot in the flowed through particulate filter elements 7 the first exhaust gas flow 17 - regardless of the load point - in the entire operating map by using a first heating element 35 especially from the on-road commercial vehicle sector even with an internal combustion engine of a larger power class, burn down.

In the operating mode shown here are all second control elements 33 in both exhaust fumes 17 . 19 opened, and all particulate filter elements 7 both exhaust fumes 17 . 19 are flowed through with exhaust gas. In the first flood of the exhaust 17 becomes the soot of all particulate filter elements 7 stalled, at the same time flows through the remaining exhaust evenly all particulate filter elements 7 the second exhaust gas flow 19 and is there cleaned of soot.

Is the process of active regeneration for the first flood 17 completed, becomes the first actuator 21 preferably provided so that the method described above is analogous to the second exhaust gas flow 19 performed, with the same advantages, especially with regard to the second heating element 37 result.

7 shows the third embodiment of the exhaust system 3 according to the 5 and 6 in a third mode. Identical and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description. This is the operating mode of a combined soot regeneration and ash mobilization operation for the first exhaust gas flow 17 , Here is the first control element 21 so driven, as related to 6 has been explained, with only the first heating element 35 active, the second heating element 37 whereas it is inactive. In contrast to the operating mode according to 6 is however in the operating mode according to 7 only the first second actuator 33.1 of the first particulate filter element 7.1 the first exhaust gas flow 17 open while the remaining second actuator 33.2 . 33.3 . 33.4 the particulate filter elements 7.2 . 7.3 . 7.4 the first exhaust gas flow 17 are closed. The whole, the exhaust tide 17 flowing exhaust gas is thus only through the first particulate filter element 7.1 directed. In this exemplary embodiment quadruples by this control of the second control elements 33 at the actively flowed through the first particle filter element 7.1 the channel velocity, which is beneficial for ash mobilization during active regeneration.

By contrast, the position of the second control elements 33 the second exhaust gas flow 19 in comparison to 6 unchanged.

Is the process of active regeneration of the first particulate filter element 7.1 the first exhaust gas flow 17 completed, the second control elements 33 the first exhaust gas flow 17 reversed, so that the corresponding procedure is analogous to the second particulate filter element 7.2 or for another, further particulate filter element 7 the first exhaust gas flow 17 is repeated. Accordingly, for example, the first second actuator 33.1 closed and the second second control element 33.2 open. Thus, sequentially all the particle filter elements can successively 7 the first exhaust gas flow 17 be regenerated with simultaneous ash mobilization.

Is this process for all particulate filter elements 7 the first exhaust gas flow 17 completed, the adjusting device 9 so energized that previously in connection with the first exhaust 17 explained method now analogous to the second exhaust gas flow 19 is performed. This is then in particular - as previously in connection with 6 addressed, also the first control element 21 redirected accordingly.

8th shows a schematic representation of the third embodiment of the exhaust system 3 according to the 5 to 7 in a fourth mode, namely a protection mode. Identical and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description. The protection operation obtains its significance in particular on the basis of the combined soot regeneration and ash mobilization operation 7 , Namely, the active regeneration is performed as shown there, especially at full load and maximum heating power of the first heating element 35 , And then reduces the exhaust gas mass of the internal combustion engine 1 abruptly, in particular due to a load reduction, for example, to idle, so may by the in 8th shown position of the first and second control elements 21 . 33 the entire, remaining exhaust gas on the one particle filter element 7.1 be steered, which is currently being actively regenerated. As a result, the exhaust gas mass increases through this particulate filter element 7.1 despite idling back to a similar high value as it was at the time of initiation of active regeneration. In the concrete case, therefore, in particular the second exhaust gas flow is here 19 completely blocked, and the entire exhaust gas is on the one hand in the first exhaust gas flow 17 and second, through the first particulate filter element 7.1 the first exhaust gas flow 17 guided. Thus, the exotherm generated by the onset of soot oxidation can be dissipated and critical temperature spikes or gradients in the particulate filter element 7.1 can be reduced. The positive benefits of the appropriate control of the actuator 9 can be further enhanced, if at the same time the measures to raise the temperature by the first heating element 35 be canceled, this is so inactivated or turned off. A corresponding protection operation for the other particulate filter elements 7 and / or for the second exhaust gas flow 19 results analogously.

Overall, it turns out that with the proposed exhaust system here 3 and the internal combustion engine 1 a possibility is provided to be able to perform an active regeneration on the one hand even with reduced heating power heating elements provided for this purpose and on the other hand a preferably operating point-independent ash mobilization in particle filter elements. In particular, both original originally reluctant regulatory goals can be achieved at the same time.

Claims (10)

Exhaust system ( 3 ) for an internal combustion engine ( 1 ), with - at least two exhaust gas flows ( 17 . 19 ), whereby in each 17 . 19 ) at least one particulate filter element ( 7 ) is arranged, and / or with - at least two fluidly arranged parallel particle filter elements ( 7 ), characterized by an adjusting device ( 9 ), with which an exhaust gas flow in the exhaust system ( 3 ) variable to the at least two exhaust gas flows ( 17 . 19 ) and / or on the at least two fluidically parallel particle filter elements ( 7 ) is divisible. Exhaust system ( 3 ) according to claim 1, characterized in that the adjusting device ( 9 ) at least one actuating element ( 11 ), which in a common collecting line ( 13 ) to the at least two fluidically parallel particle filter elements ( 7 ) is arranged such that a fluid connection to a second particulate filter element ( 7.2 ) of the at least two particulate filter elements ( 7 ) by the actuator ( 11 ) is lockable and releasable, wherein a first particulate filter element ( 7.1 ) of the at least two particulate filter elements ( 7 ) is permanently released. Exhaust system ( 3 ) according to one of the preceding claims, characterized in that the at least one adjusting element ( 11 ) Depending on the operating point is lockable and releasable. Exhaust system ( 3 ) according to one of the preceding claims, characterized in that the adjusting device ( 9 ) at least one first control element ( 21 ), with which the exhaust gas flow variable to the at least two exhaust gas flows ( 17 . 19 ) is divisible, wherein the at least one first control element ( 21 ) is preferably actuated operating point dependent. Exhaust system ( 3 ) according to one of the preceding claims, characterized in that at least one exhaust gas flow ( 17 . 19 ) at least two particulate filter elements ( 7 ), wherein the adjusting device ( 9 ) a plurality of second control elements ( 33 ) in the at least one exhaust gas flow ( 17 . 19 ), wherein every second control element ( 33 ) exactly one particle filter element ( 7 ) or a group of particulate filter elements ( 7 ) the at least one exhaust gas flow ( 17 . 19 ) assigned. Exhaust system ( 3 ) according to one of the preceding claims, characterized in that the second actuating elements ( 33 ) operating point dependent are controllable. Exhaust system ( 3 ) according to one of the preceding claims, characterized in that each exhaust gas flow ( 17 . 19 ) a separate heating element ( 35 . 37 ) for active regeneration of the particulate filter elements ( 7 ) assigned. Exhaust system ( 3 ) according to one of the preceding claims, characterized in that the adjusting device is switchable into at least two different operating modes which are selected from a group consisting of a normal operation, a pure ash mobilization operation, a pure soot regeneration operation, a combined soot regeneration and ash mobilization operation, and a protection operation , Internal combustion engine ( 1 ), with an exhaust system ( 3 ) according to one of claims 1 to 8. Internal combustion engine ( 1 ) according to claim 9, characterized by a control device ( 23 ) which is arranged to detect an operating point of the internal combustion engine ( 1 ) and / or for detecting a loading of the at least two particle filter elements ( 7 ) with soot and / or ash, and for controlling the adjusting device ( 9 ) in dependence on the operating point of the internal combustion engine ( 1 ) and / or in dependence on the loading of the particle filter elements ( 7 ) with soot and / or ash.

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