Method and device for regenerating a particulate filter arranged in the exhaust stream of an internal combustion engine

Abstract

The invention relates to a method and a device for regenerating a particulate filter, in particular a diesel particulate filter, arranged in the exhaust system of an internal combustion engine, wherein an exhaust gas stream to be cleaned is supplied to the at least one particulate filter. According to the invention, the exhaust gas stream supplied to the at least one particulate filter (3) is a raw exhaust gas stream (15) from the internal combustion engine, to which, during a regeneration operation, a hot exhaust gas stream (16') having a predetermined higher temperature than the raw exhaust gas stream (15) is added upstream of the particulate filter (3), controlled by a control and / or regulating device (10) which actuates a throttle and / or shut-off device (13) according to predetermined regeneration parameters.

Description

[0001] The invention relates to a method for regenerating a particulate filter arranged in the exhaust system of an internal combustion engine according to the preamble of claim 1 and to a device for regenerating a particulate filter arranged in the exhaust system of an internal combustion engine according to the preamble of claim 7.

[0002] In particular, the invention relates to a method and a device for regenerating particulate filters in internal combustion engines operated with excess air, such as diesel engines or gasoline engines with direct injection, as used in commercial vehicles or motor vehicles.

[0003] To minimize particulate matter, so-called particle separators or particle filters are regularly used in vehicles. A particle separator arrangement in vehicles is known, for example, from EP 1 072 765 A2. Such particle separators differ from particle filters in that the exhaust gas flow is guided along the separation structures, whereas with particle filters the exhaust gas must flow through the filter medium. As a result of this design difference, particle filters tend to become clogged, which increases exhaust backpressure, i.e., causes an undesirable increase in pressure at the exhaust outlet of an internal combustion engine, which in turn reduces engine performance and results in increased fuel consumption. An example of such a particle filter arrangement is known from EP 0 341 832 A2.

[0004] In both arrangements described above, an oxidation catalyst arranged upstream of the particulate separator or the particulate filter oxidizes the nitrogen monoxide (NO) in the exhaust gas with the help of the residual oxygen (O2) also contained therein to nitrogen dioxide (NO2), according to the following equation: 2 NO + O2 <-> 2 NO2

[0005] To regenerate the particulate filter, the NO2 reacts with the carbon-containing solid particles to form CO, CO2, N2, and NO. With the help of the strong oxidizing agent NO2, the deposited particulate matter can be continuously removed (passive regeneration). However, this device and process have the disadvantage that a large amount of toxic NO2 is formed or present in the exhaust tract.

[0006] To prevent NO2 from escaping into the environment, it is therefore important to ensure that the area between the NO oxidation catalysts and the particulate filters is sufficiently sealed. In addition to NO2, this process also produces SO3 from the sulfur contained in the fuel and / or engine oil at the platinum-containing NO oxidation catalysts. This SO3 and NO2 condense at cold spots in the exhaust system to form highly corrosive sulfuric or nitric acid, respectively. Therefore, the exhaust system up to the particulate filters must be constructed of stainless steel to reliably prevent corrosion.

[0007] Furthermore, it is known to carry out particulate filter regeneration by actively raising the exhaust gas temperature. For example, DE 10 2005 055 240 A1 describes a design in which a catalyst for the oxidation of hydrocarbons (HC oxidation catalyst), a diesel particulate filter, and then an SCR catalyst for reducing nitrogen oxide emissions are arranged in a main exhaust system in the direction of exhaust gas flow. Furthermore, a secondary exhaust system is provided, which branches off from the main exhaust system upstream of the HC oxidation catalyst and flows back into the main exhaust system after the diesel particulate filter. The secondary exhaust system contains a throttle for regulating the exhaust gas flow to be branched off, an oxidation catalyst, and a particle separator downstream of the oxidation catalyst.In such a setup, the throttle valve is closed during normal operation, allowing the entire exhaust gas flow to flow through the main exhaust system and be cleaned there. However, during a regeneration phase of the diesel particulate filter in the main exhaust system, the throttle valve is opened to direct a portion of the exhaust gas flow through the secondary exhaust system, bypassing the diesel particulate filter, and to recombine the exhaust gas flows through the main exhaust system and the secondary exhaust system at a mixing point upstream of the SCR catalyst.

[0008] This mode of operation reduces the exhaust gas mass flow through the diesel particulate filter during its regeneration phase, so that only a smaller amount of exhaust gas needs to be heated, and the diesel particulate filter can be regenerated with less energy. In addition, by splitting the exhaust gas mass flow and subsequently mixing the high-temperature exhaust flow from the main exhaust system and the low-temperature exhaust flow from the secondary exhaust system at the mixing point, the temperature of the exhaust flow through the SCR catalyst can be further reduced. The particle separator in the secondary exhaust system also prevents an exhaust flow from escaping the exhaust system without separating soot particles.

[0009] The hydrocarbons (HC) are added to the oxidation catalysts via an injection device located directly upstream of them. Since the oxidation catalysts in this type of setup oxidize NO to NO2 even in non-regeneration mode, passive filter regeneration with the help of NO2 also occurs, albeit at a low level. This means that in this type of setup, NO2 is formed even in non-regeneration mode, which is then usually emitted unused. However, due to the toxicity of NO2, this is impractical and undesirable.

[0010] It is obvious that such a structure is relatively component-intensive and also not very compact, resulting in a large overall construction volume.

[0011] US 4,485,621 A discloses a method for removing particulates from combustion exhaust gases in a system including a first gas conduit connected to an engine exhaust pipe and communicating with a capture chamber containing means for filtering or capturing particulates present in the exhaust gas. A second gas conduit is connected to the first gas conduit at a location upstream of the capture chamber and leads to a regeneration chamber containing an electrically conductive substrate supporting an oxidation catalyst. A third gas conduit carries the hot gas from the regeneration chamber and connects to the first gas conduit at a location also upstream of the capture chamber. The electrically conductive substrate material in the regeneration chamber is part of an electrical circuit and is heated by the current flowing through it.Means are provided for injecting a combustible fuel into the regeneration chamber, effectively heating and combusting the fuel-exhaust mixture therein. The heated gas then passes into the collection chamber to combust the particulates collected therein. Valve means are provided for selectively directing the exhaust flow into the collection chamber and the regeneration chamber.

[0012] DE 602 00 823 T2 discloses a system for assisting the regeneration of a catalytic particulate filter arranged in a motor vehicle diesel engine exhaust line. This filter is arranged downstream of an oxidation catalyst at the engine outlet, and it has a gas bypass circuit parallel to the catalyst connections. The gas bypass circuit is equipped with devices for controlling the circulation of gases in it and in the catalyst in order to divert a portion of the gases laden with unburned hydrocarbons into the particulate filter when regeneration of the particulate filter is triggered, without them passing through the catalyst, in order to accelerate the regeneration of the particulate filter.

[0013] It is therefore an object of the present invention to provide a method and a device for regenerating a particulate filter arranged in the exhaust system of an internal combustion engine, by means of which a functionally reliable and safe particulate filter regeneration is possible in a structurally simple manner, in particular while minimizing NO2 and / or SO3 emissions.

[0014] This object is achieved with regard to the method by the features of claim 1. With regard to the device, this object is achieved by the features of claim 7. Advantageous embodiments thereof are the subject of the dependent claims which refer back thereto.

[0015] According to the invention, the exhaust gas stream supplied to the at least one particulate filter is a raw exhaust gas stream from the internal combustion engine, to which, during regeneration operation, a hot exhaust gas stream having a predetermined higher temperature than this raw exhaust gas stream is admixed upstream of the particulate filter. This is controlled by a control and / or regulating device that activates a throttle and / or shut-off device in accordance with predetermined regeneration parameters. The raw exhaust gas stream is guided in a raw exhaust gas line, to which the hot exhaust gas stream is supplied upstream of the particulate filter via another exhaust gas line, referred to here as the supply line.

[0016] In the context of the present invention, a raw exhaust gas stream is understood to mean, in particular, an exhaust gas stream which does not flow through a NO oxidation catalyst upstream of the particulate filter and is thus an exhaust gas stream laden with soot particles, substantially free of NO2 or containing only a small amount of NO2 from combustion.

[0017] The exhaust gas stream to be heated is branched off from the raw exhaust gas stream at a branching point upstream of the at least one particulate filter, wherein this branched off exhaust gas stream is then heated by means of a heating device, preferably by means of at least one radiator catalyst, and is fed back to the raw exhaust gas stream as a heated exhaust gas stream by means of the feed line downstream of the branching point and upstream of the at least one particulate filter at an outlet point.

[0018] With such a solution according to the invention, functionally reliable particulate filter regeneration can be achieved while minimizing NO2 and / or SO3 emissions without the use of NO oxidation catalysts upstream of the at least one particulate filter. This is achieved, in particular, by minimizing the amount of exhaust gas diverted via the supply line during non-regeneration operation to a predetermined value, and in particular by substantially preventing any exhaust gas flow via the supply line. This prevents or reduces the formation of NO2 and SO3 by oxidation of NO and SO2 at the heating device, which is preferably designed as an HC oxidation catalyst.

[0019] For the regeneration phase of the particulate filter, on the other hand, the amount of exhaust gas branched off or guided via the supply line can be increased to a predetermined quantity by releasing or opening at least one throttle and / or shut-off device, and the hydrocarbons can then be added in doses. During this regeneration phase, no formation of NO2 and SO3 is to be expected because, on the one hand, their catalytic formation is suppressed in the presence of hydrocarbons, and, on the other hand, the thermodynamic NO / NO2 and SO2 / SO3 equilibria are on the side of NO and SO2 at the temperatures of, for example, over 700°C occurring during regeneration at the heating device, which is preferably designed as an HC oxidation catalyst. This means that the formation of NO2 and SO3 is then limited or prevented purely thermodynamically. Due to the exothermic reaction orOxidation of the preferred hydrocarbons subsequently enables effective and optimal thermal regeneration of the carbon-containing soot particles deposited in the downstream particulate filter.

[0020] As already explained above, in the present inventive concept the hot exhaust gas stream is preferably generated by means of at least one heating catalyst which is arranged in the supply line. This heating catalyst is preferably designed as an oxidation catalyst, in particular as an HC oxidation catalyst. Hydrocarbons are supplied to this oxidation catalyst upstream of the same. The supplied hydrocarbons are preferably fuel from the vehicle's fuel system, which is finely distributed or atomized by means of the metering device, for example via a nozzle or the like, and sprayed into the supply line upstream of the heating or oxidation catalyst at predetermined times in a predetermined amount.The oxidation catalyst preferably comprises an active component that generates a heated exhaust stream through an exothermic reaction with predetermined components of an exhaust stream—in this example, the hydrocarbons. Particularly suitable active components for an HC oxidation catalyst are elements from the platinum group metals and / or vanadium and / or tungsten and / or cerium. These active components can be used individually or in combination with one another.

[0021] Specifically, the control and / or regulating device controls a throttling and / or shut-off device, which is formed, for example, by at least one throttle and / or shut-off flap or one throttle and / or shut-off valve. Such flap or valve elements are simple and reliable to control and operate. This is arranged in the raw exhaust gas flow downstream of the branch point and upstream of the outlet point (or optionally in the branched exhaust gas flow upstream of the heating catalyst).

[0022] To ignite the added hydrocarbons, the exhaust gas stream to be heated is passed over the heating device, preferably designed as an HC oxidation catalyst, whereby the exhaust gas stream is heated. However, the heating output that can be achieved in this way is limited by the amount of oxygen available. This is because if the lambda value reaches the value 1 due to the addition of excessive amounts of hydrocarbons, oxidation of the hydrocarbons is no longer possible. To avoid this, the invention proposes supplying fresh air to the exhaust gas stream to be heated once a certain predetermined temperature has been reached and / or a certain predetermined lambda or oxygen value has fallen below or reached. This fresh air supply according to the invention causes the lambda value to be increased and thus also the maximum possible heating output.The fresh air can generally be branched off on the charge air side, specifically for example downstream of a junction of an exhaust gas recirculation line with a charge air line.

[0023] The addition of hydrocarbons, for example, or their subsequent oxidation on the HC oxidation catalyst can cause the residual oxygen content in the exhaust gas stream to be heated or that has been heated to a very significant decrease, so that complete oxidation of the hydrocarbons may no longer be possible. To prevent this, the raw exhaust gas stream can alternatively or additionally be throttled downstream of the branch point but upstream of the outlet point, for example, as a result of which more exhaust gas and thus more oxygen is then passed through the supply line. For this purpose, at least one oxygen sensor can be provided in the area of ​​the supply line downstream and / or upstream of the heating catalyst, by means of which the oxygen concentration in the exhaust gas stream can be detected. At least one temperature sensor can also be provided there.

[0024] The heating catalyst can, in principle, also be arranged outside the exhaust system, although this may lead to rapid cooling of the heating catalyst. According to a preferred embodiment, the heating catalyst is arranged in the exhaust system such that at least one exhaust gas flow, in particular the raw exhaust gas flow, flows around it at least in some areas. In this case, the exhaust gas flows conducted via the raw exhaust line and the supply line are then fluidically decoupled.

[0025] To avoid high hydrocarbon concentrations downstream of the particulate filter, for example, when hydrocarbons are used as oxidants, the filter can be equipped with a catalyst for hydrocarbon oxidation. A catalyst with hydrocarbon oxidation activity installed downstream and / or upstream of the particulate filter, after the outlet point, is also conceivable. To avoid unnecessarily high NO2 and SO3 emissions, the loading of these additional catalysts with active components and / or their volume is lower than that of the at least one heating catalyst arranged in the supply line.

[0026] The entire system can be equipped with additional catalysts to reduce NO X -reduction, such as NO X Storage catalysts and / or SCR catalysts, which can preferably be provided or arranged downstream of the particulate filter in the exhaust system. For the NO XFor storage catalysts, platinum and / or barium and / or calcium are preferred as active components. In contrast, for SCR catalysts, the use of tungsten oxide-stabilized vanadium pentoxide based on titanium dioxide, iron zeolites, copper zeolites, or cobalt zeolites is advisable.

[0027] In principle, the activity of all catalysts can be increased by the use of zeolites.

[0028] In principle, the at least one heating catalyst, preferably designed as an HC oxidation catalyst, can also be additionally provided with NO oxidation activity, whereby the NO2 content is increased in non-regenerative mode, so that, within predetermined limits, a basic regeneration option for the particulate filter with the aid of NO2 is also enabled. However, the amounts of NO2 possibly formed here are significantly lower than would be the case when using NO oxidation catalysts upstream of the particulate filter. However, in this context, it is also important to ensure that the HC oxidation catalyst is thermally stable. This, in turn, usually results in lower NO oxidation activity compared to pure NO oxidation catalysts, so that the NO quantity remains reduced for this reason as well.

[0029] The invention is explained in more detail below with reference to a drawing.

[0030] They show: Fig. 1 schematically shows a first embodiment of the invention Fig. 2 schematically shows a Fig. 1 alternative embodiment with HC oxidation catalyst arranged within the exhaust gas flow, and Fig. 3 schematically shows an enlarged detailed view of the branching pipeline section.

[0031] In the Fig. 1 shows schematically and merely by way of example a first embodiment of a regeneration device 1 according to the invention for a particle filter 3 arranged in the exhaust system 2 of an internal combustion engine not shown here.

[0032] Specifically, the exhaust line 2 here has a raw exhaust line 21 with a first line section 4, from which a supply line 5 branches off at a branching point 6 upstream of the particulate filter 3, wherein this supply line 5 is also in turn merged upstream of the particulate filter 3 at an opening point 7 with the line section 4' which continues downstream of the branching point 6 in order to form the power section 4''.

[0033] An HC oxidation catalyst 8 is arranged in the supply line 5.

[0034] The regeneration device 1 further comprises a fuel metering device 9, which, as shown very schematically, is coupled to a control and / or regulating device 10. The metering device 9 has an injection nozzle 11, designed in the manner of a bypass line and extending into the supply line 5, via which the fuel 12 is injected into the supply line 5 upstream of the HC oxidation catalyst 8 at predetermined times in predetermined quantities, in a controlled or regulated manner by the control and / or regulating device 10.

[0035] As the Fig. 1, a throttle valve 13 is also arranged upstream of the HC oxidation catalyst 8 in the region of the supply line 5, which is preferably also coupled to the control and / or regulating device 10. Furthermore, a throttle valve 14 is also arranged in the line section 4' in the region between the branch point 6 and the outlet point 7, which is preferably also coupled to the control and / or regulating device 10.

[0036] Depending on the position of the two throttle valves 13, 14, the quantity and mass of an exhaust gas flow 16 to be heated, branched off from a raw exhaust gas flow 15 coming from the internal combustion engine into the supply line 5, can be controlled and specified or regulated. Fig. In Figure 1, the open position of the throttle valves 13, 14 is shown in solid lines, and the closed position of the throttle valves 13, 14 is shown in dotted lines. The arrows 22 schematically represent the variable adjustment of the throttle valves 13, 14.

[0037] The exhaust gas stream 16 to be heated absorbs the injected fuel or hydrocarbons along its flow path upstream of the HC oxidation catalyst 8 and flows through the HC oxidation catalyst 8 in a fuel-enriched state, in which an exothermic reaction or oxidation then takes place, due to which the exhaust gas stream 16 is heated to a predetermined temperature.

[0038] This heated exhaust gas stream 16' is then fed back downstream of the HC oxidation catalyst 8 at the outlet point 7 to the raw exhaust gas stream 15' flowing via the line section 4', where the two exhaust gas streams 15', 16' mix, so that subsequently, after the mixing of the two exhaust gas streams 15', 16', a hot raw exhaust gas stream 17 flows to the particulate filter 3, where the carbon-containing soot particles stored in the particulate filter 3 are converted to CO, CO2, N2 and NO, whereby the particulate filter 3 is regenerated.

[0039] In non-regeneration mode, the throttle valve 13 is controlled such that it essentially completely closes the supply line 5, so that no or almost no exhaust gas flow reaches the particulate filter 3 via the supply line 5. In this case, the throttle valve 14 is then completely open.

[0040] In regeneration mode, however, the throttle valve 13 is opened so wide that a predetermined amount of exhaust gas is branched off from the raw exhaust gas flow 15 and, in the manner already described above, a hot raw exhaust gas flow 17 is generated, which is then fed to the particulate filter 3 for its regeneration.

[0041] In the event that, for example, the addition of fuel 12 in the supply line 5 causes the residual oxygen content in the exhaust gas flow 16 to decrease too much and thus complete oxidation of the hydrocarbons at the HC oxidation catalyst 8 does not take place, the throttle valve 14 can be more or less closed and the throttle valve 13 opened, whereby the raw exhaust gas flow 15' through the line section 4' is greatly throttled, so that a larger amount of exhaust gas 16 and thus a larger amount of oxygen flows via the supply line 5 and thus via the HC oxidation catalyst 8 to the particulate filter 3.

[0042] Likewise, as symbolized by the dashed fresh air line 19, a charge air-side fresh air flow can be mixed into the exhaust gas flow 16 to be heated during regeneration operation in order to further increase the heating output at predetermined times or when predetermined exhaust gas flow temperatures are reached and / or a predetermined lambda value or oxygen value is undershot by increasing the available amount of oxygen.

[0043] In the present example, the particle filter 3 is also assigned a NO X -Reduction catalyst 23, for example an SCR catalyst, downstream.

[0044] Furthermore, as stated in the Fig. 1 is only shown in dashed lines, a further HC oxidation catalyst 18 can also be provided downstream of the outlet point 7 and upstream of the particulate filter 3, by means of which high hydrocarbon concentrations downstream of the particulate filter 3 can be reliably avoided. Alternatively or additionally, it is also possible to provide the particulate filter 3 itself with a corresponding active component.

[0045] In the Fig. 2 schematically and by way of example, a second embodiment of a regeneration device 1 according to the invention is shown, in which, for a particularly compact and thus space-saving design, the HC oxidation catalyst 8 is arranged and accommodated within a raw exhaust gas line region that surrounds the HC oxidation catalyst 8 in a ring shape. Specifically, the raw exhaust gas stream 15 flowing via a first line section 4 of the raw exhaust gas line 21 in the direction of the HC oxidation catalyst is divided here by one or more flow guide elements 24 into a first exhaust gas stream 15' flowing only through the line section 4' of the raw exhaust gas line 21 and into a second exhaust gas stream 16 to be heated, flowing only through the HC oxidation catalyst 8. As can be seen from the Fig. 3 can be seen, for example, analogous to the embodiment according to Fig. 1 by means of a throttle valve 13 formed or arranged in the region of an orifice 20 of the flow guide elements 24, the quantity of the branched-off second exhaust gas flow 16 to be heated can be controlled in the regeneration phase or in the non-regeneration phase.

[0046] The mass of the second exhaust gas flow 16 flowing through the HC oxidation catalyst 8 is thus predetermined by the geometry of the flow guide elements 24 and / or by the position of the throttle valve 13 mounted thereon, for example. The throttle valve 13 is again controlled via the electronic control and / or regulating device 10, specifically as a function of predetermined regeneration or operating parameters, analogous to the previously described in connection with the embodiments of the Fig. 1 described control of the throttle valve 13.

[0047] Immediately in front of the outlet opening 20 of the flow guide elements 24, an injection nozzle 11 of a metering device 9 is arranged, by means of which fuel 12 can be injected into the second exhaust gas stream 14, so that an exothermic reaction takes place in the HC oxidation catalyst 8 and a hot exhaust gas stream 16' leaving the HC oxidation catalyst 8 is mixed with the raw exhaust gas stream 15' to form a hot exhaust gas stream 17. This hot exhaust gas stream 17 then flows through the particulate filter 3 and subsequently through a NO x -reduction catalyst 23, as previously described in connection with the Fig. 1 has been described.

[0048] The flow areas formed by the flow guide elements 24 then form here analogous to the designs according to the Fig. 1 and Fig. 2 in turn forms a line section 4' branching off from the line section 4 and a "feed line" 5, which are then reunited in the area downstream of the HC oxidation catalyst 8 to form a common line section 4''.

[0049] In the area of ​​the line sections 4', analogous to the design of the Fig. 1, throttle valve(s) 14 may be provided, by means of which the annular space geometry can be more or less closed. The selected representation of two throttle valves 14 does not take this annular space geometry into account and serves only as a schematic representation.

Claims

[1] Method for the regeneration of a particulate filter (3) arranged in the exhaust system (2) of an internal combustion engine, wherein an exhaust gas stream to be cleaned is supplied to the at least one particulate filter (3), wherein the exhaust gas stream supplied to the at least one particulate filter (3) is a raw exhaust gas stream (15) of the internal combustion engine, to which, during a regeneration operation, controlled by at least one control and / or regulating device (10) controlling a throttling and / or shut-off device (13) in accordance with predetermined regeneration parameters, a hot exhaust gas stream (16') having a predetermined higher temperature than the raw exhaust gas stream (15) is admixed upstream of the particulate filter (3), wherein the exhaust gas stream (16) to be heated is branched off from the raw exhaust gas stream (15) upstream of the at least one particulate filter (3) at a branching point (6),wherein this branched exhaust gas stream (16) is heated by means of a heating device (8) and is fed back to the raw exhaust gas stream (15') downstream of the branching point (6) and upstream of the at least one particle filter (3) at an outlet point (7) as a heated exhaust gas stream (16'), characterized by , that by means of the control and / or regulating device (10) a throttle and / or shut-off device (14) arranged in the raw exhaust gas flow (15') after the branching point (6) and before the outlet point (7) is controlled in such a way that during the regeneration operation a predetermined amount of exhaust gas to be heated is branched off from the raw exhaust gas flow (15) as a function of predetermined operating and / or regeneration parameters; that a fresh air flow is supplied to the exhaust gas flow (16) to be heated after reaching a predetermined heating temperature, measured on the hot exhaust gas flow (16'), and / or a predetermined lambda value; and that the control and / or regulating device (10), in the event of a drop in the oxygen content or the lambda value of the branched exhaust gas flow (16) to be heated during regeneration operation below a predetermined oxygen or lambda limit value, blocks or throttles the exhaust gas flow (15') downstream of the branching point (6) by means of the throttling and / or shut-off device (14) in such a way that a predetermined amount of exhaust gas, depending on the oxygen content or the lambda value of the raw exhaust gas flow (15) and / or depending on the oxygen content or the lambda value of the exhaust gas flow (16, 16') to be heated or heated, is branched off from the raw exhaust gas flow (15) and fed upstream of the outlet point (7) to the at least one heating device (8) provided for heating the branched exhaust gas flow (16) to be heated. [2] Method according to claim 1, characterized by that the heating device is a heating catalyst (8). [3] Method according to one of claims 1 to 2, characterized by that the throttling and / or shut-off device (13) in non-regeneration mode substantially prevents the supply of a hot exhaust gas flow (16') to the raw exhaust gas flow (15') or at least reduces it to a predetermined minimum value. [4] Method according to one of claims 1 to 3, characterized by that the hot exhaust gas stream (16') is generated by means of at least one heating catalyst (8) as a heating device, which has at least one active component which produces an exothermic reaction with predetermined components of the exhaust gas stream (16) to be heated and thus produces the heated exhaust gas stream (16'). [5] Method according to claim 4, characterized bythat the heating catalyst (8) is designed as an oxidation catalyst, preferably as an HC oxidation catalyst, through which the exhaust gas stream (16) to be heated, laden with hydrocarbon (12), flows in such a way that the exhaust gas stream (16) is heated by exothermic reaction of the hydrocarbons (12) in the oxidation catalyst. [6] Method according to claim 5, characterized by that the hydrocarbons (12) are added to the exhaust gas stream (16) to be heated upstream of the heating catalyst (8) at predetermined times in predetermined quantities by means of a metering device (9) in an electronically controlled or regulated manner. [7] Device for the regeneration of a particulate filter (3) arranged in the exhaust system (2) of an internal combustion engine, with at least one particulate filter (3) through which an exhaust gas stream to be cleaned flows, wherein the exhaust gas stream supplied to the at least one particulate filter (3) by means of a raw exhaust gas line (21) is a raw exhaust gas stream (15) of the internal combustion engine, to which, for a regeneration operation, upstream of the particulate filter (3) a hot exhaust gas stream (16') having a predetermined higher temperature than the raw exhaust gas stream (15) can be supplied by means of a further exhaust gas line as a supply line (5) which can be shut off to a predetermined extent by means of at least one throttling and / or shut-off device (13),wherein the supply line (5) branches off from the raw exhaust line (21) at a branching point (6) upstream of the at least one particle filter (3) and is led back into the raw exhaust line (21) at a mouth point (7) downstream of this branching point (6) and upstream of the at least one particle filter (3), characterized by , that in a line section (4') of the raw exhaust gas line (21) after the branching point (6) and before the outlet point (7) a throttle and / or shut-off device (14) which can be controlled by means of a control and / or regulating device (10) is arranged, by means of which the amount of exhaust gas to be branched off from the raw exhaust gas flow (15) can be adjusted; that the supply line (5) is fluidically coupled to a fresh air line (19) which can be shut off by means of a shut-off device and with which a charge air-side fresh air flow or a charge air flow branched off downstream of the junction of an exhaust gas recirculation line into a charge air line can be supplied to the supply line (5); and that the control and / or regulating device (10) is designed, in the event of a drop in the oxygen content or the lambda value of the branched exhaust gas flow (16) to be heated during regeneration operation below a predetermined oxygen or lambda limit value, to block or throttle the exhaust gas flow (15') downstream of the branching point (6) by means of the throttling and / or shut-off device (14) in such a way that a predetermined amount of exhaust gas, depending on the oxygen content or the lambda value of the raw exhaust gas flow (15) and / or depending on the oxygen content or the lambda value of the exhaust gas flow (16, 16') to be heated or heated, is branched off from the raw exhaust gas flow (15) and fed upstream of the outlet point (7) to the at least one heating device (8) provided for heating the branched exhaust gas flow (16) to be heated. [8] Device according to claim 7, characterized bythat at least one heating device, in particular at least one heating catalyst (8), is arranged in the supply line (5). [9] Device according to claim 8, characterized by that the heating catalyst (8) is designed as an oxidation catalyst. [10] Device according to claim 9, characterized by that a metering device (9) is provided, by means of which hydrocarbons (12) or the like for an exothermic reaction can be metered into the exhaust gas stream (16) to be heated upstream of the at least one heating catalyst (8). [11] Device according to claim 9 and 10, characterized by that the heating catalyst (8) is an HC oxidation catalyst, and that the hydrocarbons (12) are preferably formed by fuel. [12] Device according to one of claims 7 to 11, characterized bythat the at least one throttling and / or shut-off device (13, 14) is formed by a throttling and / or shut-off flap or a throttling and / or shut-off valve. [13] Device according to one of claims 8 to 12, characterized by that in the region of the supply line (5) downstream and / or upstream of the heating catalyst (8) an oxygen sensor for detecting the O2 concentration in the exhaust gas stream (16, 16') and / or a temperature sensor for detecting the temperature in the exhaust gas stream (16, 16') is provided. [14] Device according to one of claims 8 to 13, characterized by that the heating catalyst (8) is arranged in the exhaust gas line (2) in such a way that at least one exhaust gas flow (15') flows around it, at least in some areas. [15] Device according to one of claims 8 to 14, characterized bythat at least one oxidation catalyst (18), in particular an oxidation catalyst for the oxidation of hydrocarbons, is arranged downstream of the outlet point (7) and upstream and / or downstream of the particle filter (3) in the raw exhaust gas line (4). [16] Device according to claim 15, characterized by that the at least one oxidation catalyst (18) arranged downstream of the outlet point (7) is designed as an HC oxidation catalyst which has a lower content of hydrocarbon-oxidizing active component(s) and / or a smaller volume than a heating catalyst in the feed line (5) which is also designed as an HC oxidation catalyst (8). [17] Device according to one of claims 7 to 16, characterized by that the at least one particle filter (3) is additionally provided with an HC oxidation activity. [18] Device according to one of claims 8 to 17, characterized bythat the at least one heating catalyst (8) is additionally provided with a NO oxidation activity. [19] Device according to one of claims 8 to 18, characterized by that in the exhaust system (2), in particular downstream of the at least one particle filter (3), a NO X -reduction catalyst (17), in particular at least one NOx storage catalyst and / or at least one SCR catalyst, is arranged.

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