DE102021004046B4 - Exhaust aftertreatment system for an internal combustion engine and vehicle - Google Patents

Abstract

Exhaust gas aftertreatment system (1) for an internal combustion engine (2) with at least one catalytic device (4) which is arranged in an exhaust tract (3.2) and has a catalytic converter housing (7), and at least one connecting device (5), with the connecting device (5 ) the exhaust pipe (6) can only be separated non-destructively, and the connecting device (5) between two components (5.1, 5.2) of an exhaust pipe (6) and/or the Catalyst housing (7) is arranged in order to connect the two components (5.1, 5.2), characterized in that the connecting device (5) consists of at least one cutout (9) made in a first component (5.1) and at least one cutout on a second, to the first (5.1) deviating component (5.2) provided detent (10) is formed, wherein the detent (10) is set up in a Montageschr itt to engage in the recess (9) and to hook into it to connect the two components (5.1, 5.2).

Description

The invention relates to an exhaust gas aftertreatment system for an internal combustion engine according to the type defined in more detail in the preamble of claim 1 and to a vehicle with such an exhaust gas aftertreatment system.

Exhaust systems for internal combustion engines are known from the general state of the art. For reasons of environmental protection, exhaust gases emitted by an internal combustion engine are filtered and after-treated with the help of catalytic converters. This reduces emissions of harmful particles and polluting gases into nature. Such an exhaust system typically includes an exhaust tract connected to an outlet of an internal combustion engine with a mostly tubular exhaust line and one or more particle filters and catalytic converters. Since such particulate filters and catalytic converters work most efficiently within a specific map and/or can be damaged when specific operating temperatures are reached, compliance with the operating conditions for these components is monitored with the aid of sensors. For reasons of cost, it is desirable to keep the complexity of such a monitoring system low.

Stricter climate guidelines make it necessary to improve the filtration efficiency of existing exhaust systems. Due to the limited installation space available, integrating additional particle filters and/or catalytic converters can be problematic. If there is no installation space available on a vehicle underbody in the vicinity of the internal combustion engine in the so-called hot end, it is necessary to provide the corresponding components further downstream, in the so-called cold end. For design and assembly reasons, it is often difficult to design an exhaust pipe of the exhaust system in one piece.

However, a multi-part exhaust line can lead to stricter requirements for the sensor monitoring of the exhaust system.

From the DE 10 2006 016 906 A1 a device for monitoring an exhaust gas catalyst in the exhaust system of an internal combustion engine is known. Catalytic converters can lose some or all of their effectiveness when exposed to high temperatures. Reliable monitoring of the exhaust gas catalytic converter is possible by means of the device disclosed in the publication. The device comprises a temperature-sensitive component in order to assume a temperature which is correlated with the temperature of the exhaust gas catalyst. A temperature-dependent characteristic component parameter of the temperature-sensitive component is monitored with the aid of a measuring arrangement. A measuring arrangement comprising the temperature-sensitive component is inextricably linked to the exhaust gas catalytic converter or an exhaust gas-carrying component of the exhaust tract. Unsolvable here means a non-destructively solvable connection. In particular, the measuring arrangement is soldered or welded to the catalytic converter or the corresponding part of the exhaust gas tract.

Furthermore, from the DE 11 2006 003 631 T5 a serviceable exhaust gas aftertreatment system is known. This includes a multi-part exhaust pipe, wherein individual sections of the multi-part exhaust pipe can be detached from one another at a parting line in order to open the exhaust pipe. This ensures accessibility to a partial segment of the exhaust pipe in which a particle filter and/or a catalytic converter are provided. The particle filter or the catalytic converter can thus be replaced comparatively easily.

the DE 10 2009 007 766 A1 describes a connecting device for exhaust gas aftertreatment units, in which, in one embodiment of the connecting device, contact areas of a first and second connecting element to be connected each have two diametrically opposite stepped shoulders, which serve as anti-rotation means. The two connecting elements can be braced relative to one another in the direction of the central axis by means of a tensioning means.

From the DE 10 2013 021 981 A1 an exhaust system is known which has a holding element arranged between a tailpipe and a tailpipe trim. The holding element is slipped onto the tailpipe, the tailpipe cover is pushed over the tailpipe and the holding element and locked in a form-fitting manner with the holding element.

the CN 1 13 286 964 A describes a fluid connection device with two connecting pieces, which are intended for the purpose that one connecting piece is inserted into the other connecting piece, the connecting pieces being connected to one another by means of a double connection by means of an elastic snap connection and by means of a bayonet closure, this elastic snap Closure is designed so that it can not be dismantled without destruction.

The present invention is based on the object of specifying an improved exhaust gas aftertreatment system for an internal combustion engine in agreement with current authorities guidelines permit the provision of at least one unmonitored catalytic device.

According to the invention, this object is achieved by an exhaust gas aftertreatment system for an internal combustion engine having the features of claim 1 and a vehicle having the features of claim 9 . Advantageous configurations and developments result from the dependent claims.

In an exhaust gas aftertreatment system for an internal combustion engine with at least one catalytic device arranged in an exhaust tract and at least one connecting device provided for an exclusively destructible, detachable connection, the connecting device is arranged between two components of an exhaust pipe and/or a catalytic converter housing through which a main exhaust gas mass flow flows during operation of the internal combustion engine. to connect the two components.

According to the invention, the connecting device is formed by at least one recess made in a first component and at least one latching lug provided in a second component that differs from the first component, with the latching lug being set up to engage in the recess in an assembly step for connecting the two components and to engage in to hook this one. Because the latch catches in the recess, the connecting device can no longer be released in the opposite direction to its mounting direction. Since a pairing of recess and locking lug involves two particularly simple components, the construction effort involved in producing the connecting device can also be kept to a minimum. The exhaust gas aftertreatment system according to the invention can thus be manufactured particularly easily and inexpensively.

Since the connecting device can only be detached in a destructible manner, the exhaust pipe can be viewed as a one-piece exhaust pipe in accordance with the applicable guidelines. The provision of additional sensors for monitoring the catalytic device is therefore obsolete. Due to the multi-part design of the exhaust tract, the exhaust aftertreatment system can also be installed in demanding installation space situations with comparatively little assembly effort. Due to the multi-part design, no adjustment of existing assembly steps is necessary.

Since the connection device is initially installed in an assembly plant of a vehicle manufacturer, it is possible to limit the spread of the connection device on the open market. Due to a lack of spare parts, third parties cannot subsequently install the connecting device after the exhaust tract has been manipulated. Subsequent modification of the exhaust pipe can thus be identified particularly easily. For example, to connect a separate exhaust line, it is necessary to weld the two separate line sections. However, a corresponding weld seam can be easily recognized.

The exhaust tract can include one or more, for example two, exhaust gas lines. A corresponding connection device can be provided in one, several or all exhaust gas lines. The connecting device can be provided in all exhaust gas lines at the same axial position, or it can also be attached in different exhaust gas lines at different points. For example, it can connect two components forming the exhaust line in one exhaust line and connect a component forming the exhaust line and a component forming the catalytic converter housing in a further exhaust line.

An advantageous further development of the exhaust gas aftertreatment system provides that the catalytic device is arranged downstream of the connecting device in the direction of flow of the main exhaust gas mass flow, with the catalytic device being formed in particular by a three-way catalytic converter. If the catalytic device is located downstream of the connecting device, then the catalytic device can be provided in particular in the cold end of the exhaust gas tract. As a result, the space available on a vehicle for installing the catalytic device can be utilized even better. A three-way catalytic converter is a tried and tested catalytic converter for after-treatment of exhaust gases. This ensures broad applicability of the exhaust gas aftertreatment system according to the invention.

According to a further advantageous embodiment of the exhaust gas aftertreatment system, at least one particle filter, in particular an Otto particle filter, is arranged in the main exhaust gas mass flow upstream of the connecting device. The particle filter can be monitored by a sensor system. By connecting several exhaust gas aftertreatment components in series in the main exhaust mass flow, the exhaust gas can be cleaned particularly extensively. This means that stricter legal requirements can also be met in the future.

For these stricter requirements is in a further advantageous embodiment of the Exhaust aftertreatment system, an additional catalyst, in particular three-way catalyst, or absorber provided upstream of the connecting device in the main exhaust gas mass flow. With the help of the exclusively destructible, detachable connection device, the exhaust gas aftertreatment system can be designed in such a way that the catalytic converter downstream of the non-destructible, detachable connection device does not have to be monitored with the aid of sensors additionally provided for this downstream catalytic converter.

Within the scope of the invention, the internal combustion engine for which the exhaust gas aftertreatment system according to the invention is provided can be designed as a diesel engine, with the catalytic device being designed as an SCR catalytic converter.

A further advantageous embodiment of the exhaust gas aftertreatment system also provides that the connecting device has at least two, in particular five pairs of recesses and locking lugs, the pairs being distributed in a circumferential direction around the components and arranged on them, in particular at the same axial position in the direction of flow of the main exhaust mass flow. If a force is exerted on the connecting device counter to the assembly direction, there is a risk that the latching lug accommodated in a recess will break off. By providing additional pairings of recess and latching lug, a resistance to detachment of the connecting device, which is liable to be destroyed, can be increased. The pairings are advantageously arranged evenly around the components connected to the connecting device. Thus, the connected components are evenly loaded. If the pairings are in the same axial position in the direction of the main exhaust gas mass flow, the connecting device can be made comparatively short in a direction parallel to the exhaust gas line. As a result, an available installation space can be used even more efficiently and material costs can be saved.

According to a further advantageous embodiment of the exhaust gas aftertreatment system, a first and/or both components has at least one cavity for accommodating at least one section of the respective other component. In this way, the two components to be connected can be pushed into one another during assembly. This ensures a simple and reliable alignment and assembly of the components to be connected.

Preferably, at least one protective element is arranged in a radial direction between the connecting device and a central axis running through the exhaust gas tract and/or a connection of the first and second component is secured by means of the connecting device by a pipe clamp pulled over and tightened on the outside of the two components in the radial direction. A particularly secure connection of the two components is possible with the aid of the protective element and/or the pipe clamp. The protective element prevents the formation of vortices due to the main exhaust gas mass flow flowing around the locking lugs. The detents are thus covered by the protective element, so that the main exhaust gas mass flow is deflected past the detent. This also protects the latching lugs or the connecting device from excessive thermal stress and reduces or completely prevents the occurrence of turbulence-related noise.

The connection between the two components can be additionally secured with the help of the pipe clamp. It is thus even more difficult to detach the connected components, which prevents unintentional detachment and thus destruction of the components connected via the connecting device. The pipe clamp can also be tightened using shear bolts. This also ensures that the pipe clamp can only be released in a destructible manner.

According to the invention, a vehicle includes an exhaust gas aftertreatment system as described above. The vehicle can be any vehicle such as a car, truck, van, bus or the like. The vehicle can be designed purely as a combustion vehicle or as a hybrid vehicle. In general, it is also conceivable to provide an exhaust gas aftertreatment system according to the invention on a stationary internal combustion engine, for example an engine of a combined heat and power plant.

The catalytic device of the exhaust gas aftertreatment system is preferably arranged on a vehicle underbody. As a result, the available installation space for providing the exhaust gas aftertreatment system according to the invention and its components can be used particularly efficiently.

Further advantageous refinements of the exhaust gas aftertreatment system according to the invention and the vehicle according to the invention also result from the exemplary embodiments, which are described in more detail below with reference to the figures.

• 1 eine schematische Draufsicht auf einen Abgastrakt eines Verbrennungsmotors gemäß verschiedener Ausführungsformen des Abgastrakts;
• 2 eine schematische Schnittansicht einer erfindungsgemäßen Verbindungseinrichtung gemäß einer ersten Ausführungsform;
• 3 eine schematische Schnittansicht einer erfindungsgemäßen Verbindungseinrichtung gemäß einer alternativen Ausführungsform; und
• 4 eine schematische Draufsicht auf eine erfindungsgemäße Verbindungseinrichtung in Richtung einer durch den Abgastrakt verlaufenden Mittelachse.

show:

• 1 a schematic plan view of an exhaust system of an internal combustion engine according to various embodiments of the exhaust system;
• 2 a schematic sectional view of a connecting device according to the invention according to a first embodiment;
• 3 a schematic sectional view of a connecting device according to the invention according to an alternative embodiment; and
• 4 a schematic top view of a connecting device according to the invention in the direction of a central axis running through the exhaust tract.

1 shows an exhaust gas aftertreatment system 1 according to the invention, connected to an internal combustion engine 2. An air intake tract 3.1 upstream of the internal combustion engine 2 comprises at least one line 15 for supplying fresh air to the internal combustion engine 2. An exhaust tract 3.2 downstream of the internal combustion engine 2 comprises at least one exhaust line 6 for exhaust gas aftertreatment and for ejecting a main exhaust gas mass flow m to the environment. The line 15 and/or the exhaust gas line 6 can be designed as a tube, for example. The pipe can have any cross-sectional shape, for example a circular cross-section, and the flow is in a flow direction SR. The exhaust tract 3.2 opens into an exhaust pipe, not shown. In the example in 1a) includes the exhaust tract 3.2 an exhaust pipe 6, and in 1b) two exhaust pipes 6.

The exhaust aftertreatment system 1 comprises at least one catalytic device 4, for example a three-way catalytic converter and a connection device 5 designed exclusively for a destructible, detachable connection Monitoring of the arranged in the hot end of the exhaust gas aftertreatment system 1 catalytic device 4 and the particle filter 8, the respective components are monitored with the help of sensors. For this purpose, lambda probes 16.1, temperature sensors 16.2 and at least one differential pressure sensor 16.3 are used as sensors.

In order to avoid construction and assembly work and the associated costs, a catalytic device 4 arranged in the so-called cold end of the exhaust gas tract 3.2 is not monitored by means of sensors. In order for this to be permitted in certain countries, an exhaust pipe 6 may only be made in one piece. For design and/or assembly reasons, however, it may be necessary for at least one exhaust line 6 of the exhaust tract 3.2 to be designed in several parts, at least in two parts.

With the help of the connecting device 5, the exhaust pipe 6 cannot be separated without being destroyed. Thus, according to applicable guidelines, the exhaust gas line 6 can be considered to be designed in one piece. The connecting device 5 is integrated into the exhaust pipe 6 and/or into a catalytic converter housing 7 surrounding the catalytic device 4 . In doing so, as in 2 B) shown, in the case of an exhaust tract 3.2 with two exhaust pipes 6, the connecting device 5 can also be arranged at different positions in the individual exhaust pipes 6. For example, in the in 2 B) The exhaust pipe 6 shown above connects two pipe sections forming the exhaust pipe 6 by means of a connecting device 5 and in 2 B) Exhaust line 6 shown below, a pipe section forming the exhaust line 6 is connected to the catalytic converter housing 7 by means of a connecting device 5 .

2 shows a schematic sectional view of a first embodiment of the connecting device 5. Shown are two components 5.1 and 5.2, which form a section of the exhaust pipe 6 and/or a section of the catalytic converter housing 7. The two components 5.1 and 5.2 have the main exhaust gas mass flow ṁ flowing through them in the direction of flow SR. For example, the components 5.1 and 5.2 are as in 2 and 3 shown to annular segments. A first of the components 5.1 has at least one recess 9 for receiving at least one latching lug 10 comprised by a second component 5.2. To connect the two components 5.1 and 5.2, they are pushed into one another in the direction of a mounting direction M, so that the latching lug 10 engages in the recess 9 and hooks there. Thus, the components 5.1 and 5.2 can no longer be detached from one another when a force is exerted against their mounting direction M.

At least one recess 9 and at least one latching lug 10 can be included in one of the two components 5.1 and/or 5.2. For example, the first component 5.1 can only have recesses 9 and the second component 5.2 can only have locking lugs 10, or it can also have both recesses 9 and locking lugs 10 on the two components 5.1 and 5.2. In the example in 2 the detent 10 is connected directly to a wall 17 of the exhaust pipe 6 . In 2a) the components 5.1 and 5.2 are shown in the dismantled state. In 2 B) the two components 5.1 and 5.2 are shown in their assembled state.

Since the main exhaust gas mass flow ṁ flows through the exhaust pipe 6, vortices can form on protruding projections, for example the locking lug 10, which lead to noise. By Providing a protective element 12 between a pairing of recess 9 and latching lug 10 and a central axis 13 running through the exhaust pipe 6 in a radial direction r allows the main exhaust gas mass flow ṁ to be guided through the exhaust pipe 6 in such a way that the latching lug 10 is prevented from being passed over. In this way, in addition to a noise reduction, a thermal load on the connecting device 5 is also reduced. The protective element 12 can be in an in 4 Considered the circumferential direction U shown, be completely circular in itself. For example, the protective element 12 can be formed by an inner tube. Several small protective elements 12 (not shown) can also be provided in the circumferential direction U only at the points at which recesses 9 or latching lugs 10 are provided on the components 5.1 and/or 5.2. In particular, the recesses 9 and the latching lugs 10 are located at the same axial position when viewed in an axial direction Ax coinciding with the flow direction SR. As a result, an expansion of the components 5.1 and 5.2 in the axial direction Ax can be reduced.

As additional protection against unintentional loosening of the connecting device 5, the components 5.1 and 5.2 can also be held together by a pipe clamp 14.

3 shows an alternative embodiment of the connecting device 5. The two components 5.1 and 5.2 each have a cavity 11 for receiving a section of the respective other component 5.1 and 5.2. In this way, the components 5.1 and 5.2 to be connected can be centered in relation to one another, which simplifies the assembly of the exhaust pipe 6. Furthermore, as a result, access to the recesses 9 and the latching lugs 10 is made more difficult, as a result of which the exhaust pipe 6 is more difficult to manipulate or modify. Here, too, the components 5.1 and 5.2 can be secured by a protective element 12 and a pipe clamp 14. Analog shows 3a) the components 5.1 and 5.2 in dismantled and 3b) in mounted condition.

4 shows a plan view of the connecting device 5 in the direction of the central axis 13. 4 illustrates how the recesses 9 and latching lugs 10 are distributed in the circumferential direction U around the components 5.1 and 5.2 to be connected. In the example in 4 the connecting device 5 has three recesses 9 and three latching lugs 10 . In particular, these are distributed uniformly in the circumferential direction U. In the example in 4 the respective recesses 9 and locking lugs 10 have an angular distance of 120° to one another. In general, the connecting device 5 can have any number of pairs of recesses 9 and latching lugs 10 . These can also each have a different angular distance from one another in the circumferential direction U.

Claims (9)

Exhaust gas aftertreatment system (1) for an internal combustion engine (2) with at least one catalytic device (4) which is arranged in an exhaust tract (3.2) and has a catalytic converter housing (7), and at least one connecting device (5), with the connecting device (5 ) the exhaust pipe (6) can only be separated non-destructively, and the connecting device (5) between two components (5.1, 5.2) of an exhaust pipe (6) and/or the Catalyst housing (7) is arranged in order to connect the two components (5.1, 5.2), characterized in that the connecting device (5) comprises at least one recess (9) made in a first component (5.1) and at least one on a second, to the first (5.1) deviating component (5.2) provided detent (10) is formed, wherein the detent (10) is set up in a Montagesch rode to connect the two components (5.1, 5.2) to engage in the recess (9) and to hook into it. Exhaust aftertreatment system (1) after claim 1 , characterized in that the catalytic device (4) in the flow direction (SR) of the main exhaust gas mass flow (ṁ) is arranged downstream of the connecting device (5), the catalytic device (4) being designed as a three-way catalytic converter. Exhaust aftertreatment system (1) after claim 1 or 2 , characterized in that upstream of the connecting device (5) at least one particle filter (8) is arranged in the main exhaust gas mass flow (ṁ). Exhaust aftertreatment system (1) after claim 3 , characterized in that upstream of the connecting device (5) at least one further catalytic device (4) is provided. Exhaust aftertreatment system (1) according to one of Claims 1 until 4 , characterized in that the connecting device (5) has at least two pairings of recess (9) and latching lug (10), the pairings being distributed in a circumferential direction (U) circumferentially around the components (5.1, 5.2) and essentially at one are arranged in the same axial position in the direction of flow (SR) of the main exhaust gas mass flow (m). Exhaust aftertreatment system (1) according to one of Claims 1 until 5 , characterized in that a first and/or both components (5.1, 5.2) has at least one cavity (11) for receiving at least one section of the respective other component (5.1, 5.2). Exhaust aftertreatment system (1) according to one of Claims 1 until 6 , characterized in that at least one protective element (12) is arranged in a radial direction (r) between the connecting device (5) and a central axis (13) running through the exhaust tract (3.2) and/or a connection of the first (5.1) and second component (5.2) by means of the connecting device (5) by means of a pipe clamp (14) pulled over and tightened on the outside of the two components (5.1, 5.2) in the radial direction (r). Vehicle, characterized by an exhaust gas treatment system (1) according to one of Claims 1 until 7 . vehicle after claim 8 , characterized in that the catalytic device (4) of the exhaust gas treatment system (1) is arranged on a vehicle underbody.

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