Motor vehicle having an internal combustion engine and having an exhaust-gas aftertreatment device, exhaust-gas aftertreatment device for an internal combustion engine, and particle filter

Abstract

The invention relates to a motor vehicle (K) having an internal combustion engine (100) and having an exhaust-gas aftertreatment device (10), which has a particle filter (20) having a particle filter housing (30) and having a filter body arrangement (40) which is accommodated in the particle filter housing (30) and is designed to separate particles out of an exhaust-gas flow (12) that is able to be emitted by the internal combustion engine and passes through the filter body arrangement (40) when the latter is used as intended. The filter body arrangement (40) has filter body elements (42, 44) which are separated from one another by means of at least one liquid-tight layer (60) that is oriented at least substantially in the direction of longitudinal extension (x) of the particle filter (20). Further aspects of the invention relate to an exhaust-gas aftertreatment device (10) for an internal combustion engine (100), and to a particle filter (20).

Description

[0001] Motor vehicle with an internal combustion engine and with an exhaust gas aftertreatment device, exhaust gas aftertreatment device for an internal combustion engine and particulate filter

[0002] The invention relates to a motor vehicle with an internal combustion engine and an exhaust gas aftertreatment device comprising a particulate filter, a particulate filter housing, and a filter body assembly designed to separate particles from an exhaust gas stream emitted by the internal combustion engine and flowing through the filter body assembly during its intended use, and which is accommodated in the particulate filter housing. Further aspects of the invention relate to an exhaust gas aftertreatment device for an internal combustion engine and a particulate filter.

[0003] While diesel particulate filters have been used for exhaust gas aftertreatment in diesel engines for some time, gasoline particulate filters are now also being increasingly used. This is due to increasingly stringent emissions regulations and to further reduce the proportion of soot particles in the exhaust gas produced by gasoline engines, which is already low compared to diesel engines. A gasoline particulate filter (OPF), for example, can feature a porous ceramic brick (ceramic brick), whose porous surface ensures that soot particles are reliably filtered out of the exhaust gas, thus meeting current emissions legislation worldwide. As the respective legislation becomes increasingly stringent, the requirements for the filtration efficiency (FE) of a particulate filter increase. This situation can be addressed at the component level of the particulate filter by increasingly fine, porous structures on the ceramic brick.

[0004] DE 102018216841 A1 discloses a filter for filtering exhaust gas from an internal combustion engine, comprising an inlet side and an outlet side. The filter is formed from a plurality of nonwoven layers, each of which has a gas-impermeable end region formed by a smooth band strip on the inlet side and the outlet side. The nonwoven layers have, at least on one side, a corrugated band strip arranged along the smooth band strip. Two adjacent nonwoven layers are spaced apart from one another on the inlet side or the outlet side. Two directly adjacent smooth band strips are alternately connected to one another in a gas-tight manner on the inlet side and the outlet side.

[0005] The object of the present invention is to provide a motor vehicle with an internal combustion engine in which fail-safe and effective exhaust gas aftertreatment can be carried out. Furthermore, the object of the invention is to provide a corresponding exhaust gas aftertreatment device for an internal combustion engine and a particulate filter.

[0006] This object is achieved by a motor vehicle having the features of patent claim 1, by an exhaust aftertreatment device having the features of patent claim 9, and by a particulate filter according to patent claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the subclaims.

[0007] A first aspect of the invention relates to a motor vehicle with an internal combustion engine and with an exhaust gas aftertreatment device comprising a particulate filter, a particulate filter housing, and a filter body assembly configured to separate particles from an exhaust gas stream emitted by the internal combustion engine and flowing through the filter body assembly during its intended use, and accommodated in the particulate filter housing. The filter body assembly can therefore be used overall, when used as intended, particularly during exhaust gas aftertreatment using the filter body assembly, to filter particles from the exhaust gas stream passing through the filter body assembly during operation of the internal combustion engine.

[0008] According to the invention, the filter body arrangement comprises filter body elements which are separated from one another by means of at least one liquid-tight, in particular watertight, layer oriented at least substantially in the longitudinal direction of the particulate filter. This is advantageous because the liquid-tight layer, which can also be referred to as a separating layer, can prevent the entire filter body arrangement from becoming undesirably saturated with liquid, in particular water, if there is liquid in the exhaust gas aftertreatment device that comes into contact with the filter body arrangement. This undesirable saturated suction can lead to an impermissibly high exhaust gas backpressure when the exhaust gas flow flows through the filter body arrangement, which can cause malfunctions in the operation of the internal combustion engine.In addition to the longitudinal direction of extension, the filter body elements can also be completely separated from one another in the transverse direction of extension, in that the at least one liquid-tight layer preferably extends between two opposing housing regions of the particulate filter housing and is connected to these opposing housing regions. The layer can, in particular, be oriented parallel to a plane spanned by the longitudinal and transverse directions of extension of the particulate filter. The longitudinal direction of extension can preferably correspond to a flow direction of the exhaust gas flow. In the flow direction, the exhaust gas flow can pass through the filter body elements during intended use of the particulate filter.

[0009] The invention is based on the finding that the filter body elements, which are usually made of a ceramic material, have fine structures, in particular pores, which enable the particles to be filtered out of the exhaust gas stream, but also promote any possible full suction of one of the filter body elements, in particular due to a capillary effect, through which liquid can be conveyed through the filter body element even against the direction of gravity. If a sufficiently large quantity of liquid, in particular water, which comes into contact with the filter body element, in the worst case scenario the entire filter body element can become full suction. If the particulate filter has a single, coherent filter body element, this can lead to the filter body arrangement becoming completely saturated.Water is a liquid by-product of the combustion of a fuel-air mixture during the fired operation of the internal combustion engine. Large quantities of water can collect in the exhaust gas aftertreatment system, especially during extended operation of the internal combustion engine at low load points. In addition to the formation of water as a by-product as a result of combustion, water can also enter the exhaust gas aftertreatment system of the vehicle from the environment. This can happen, for example, in heavy rain or when driving through a car wash. In the worst case scenario, several liters of water can collect as a liquid in a muffler of the exhaust gas aftertreatment system and other geodetically low-lying points of the exhaust gas aftertreatment system. This can then slosh up to the particulate filter as a result of the vehicle's moving operation, i.e. due to driving dynamics.Due to the porous structure of a filter body element, it can potentially become completely saturated with water, even if only the lower part of the filter body element (in the direction of gravity) is submerged in water. The risk of complete absorption is particularly high when the particulate filter is used as an underbody particulate filter. A water-soaked filter body element, which - if the particulate filter is designed as a gasoline particulate filter, can also be referred to as an OPF block - has several serious disadvantages. When soaked with liquid water, the exhaust backpressure is significantly increased via the saturated filter body element during operation of the internal combustion engine. This can lead to false errors in various diagnostics relating to the particulate filter during operation of the internal combustion engine.At temperatures below freezing, i.e. below 0 °C, the water absorbed in the filter body element can freeze and, as a result, the exhaust gas back pressure can increase considerably, which can even lead to the exhaust gas aftertreatment device becoming completely blocked. This causes the vehicle to break down. In this case, the particulate filter can also be damaged by the extreme exhaust gas back pressure. This is where the invention comes in, whereby the liquid-tight layer can prevent all of the filter body elements from becoming saturated, so that at least one of the filter body elements can be prevented from becoming saturated by the layer and the functionality of the exhaust gas aftertreatment device can be ensured even when liquid is present in the exhaust gas aftertreatment device and at temperatures below freezing.This allows for fail-safe and effective exhaust gas aftertreatment even under such adverse conditions.

[0010] In an advantageous development of the invention, the at least one liquid-tight layer is oriented at least substantially perpendicular to the direction of gravity. This is advantageous because the layer thereby prevents liquid columns, in particular water columns, that form in the exhaust gas aftertreatment device from undesirably penetrating all filter body elements, without the layer taking up an unnecessarily large amount of installation space within the particulate filter housing. The at least one layer can be assigned to the filter body arrangement and thus also be a layer of the particulate filter. The expression "oriented at least substantially perpendicular to the direction of gravity" is to be understood in the context of the present disclosure that the at least one layer can preferably lie in a plane whose normal vector can be oriented parallel to the direction of gravity.However, the expression “oriented at least substantially perpendicular to the direction of action of gravity” can also be understood within the scope of the disclosure to mean that the normal vector and the direction of action of gravity enclose an angle a, where a can correspond, for example, to one of the angle values ​​1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°.

[0011] In a further advantageous development of the invention, the filter body arrangement comprises a plurality of filter body elements, of which two of the filter body elements are separated from each other by at least one additional layer, which is oriented parallel to the at least one liquid-tight layer and is also liquid-tight. This advantageously allows only a small volume of the filter body arrangement to be saturated with the liquid when the liquid level in the exhaust gas aftertreatment device is low.

[0012] The following example serves to illustrate this:

[0013] For example, if the particulate filter has two additional layers, these two additional layers, together with the layer, can separate four filter body elements of the filter body assembly from each other in a fluid-tight manner. In the direction of gravity, the following sequence can then be provided: first filter body element - fluid-tight layer - second filter body element - first additional layer - third filter body element - second additional layer - fourth filter body element.

[0014] If, in this example, the second additional layer is geodetically above the liquid level, only the geodetically lowest of the four filter body elements, in this example the fourth filter body element, will be saturated, whereas the three filter body elements (first, second, and third filter body elements) arranged geodetically above the fourth filter body element can be effectively prevented from becoming saturated. Overall, the liquid-tight layer and the additional layers can thus form several separation layers for different liquid levels.

[0015] In a further advantageous development of the invention, the at least one liquid-tight layer and the filter body elements are made of different materials. This facilitates, for example, a liquid-tight connection between the particulate filter housing and the liquid-tight layer. Thus, the layer and the particulate filter housing can be formed from the same metallic material and connected to each other, for example, by a material bond.

[0016] In a further advantageous development of the invention, the at least one liquid-tight layer is formed from a material with a higher thermal conductivity than the material of the filter body elements. This promotes rapid heat distribution along the filter body arrangement, whereby thermal stresses can be reduced. In a further advantageous development of the invention, the material of the at least one liquid-tight layer is metallic. This can advantageously result in faster heat distribution within the particulate filter housing and along the filter body elements. In other words, the liquid-tight layer can therefore be formed from a metallic material, which can contribute to better heating of the particulate filter during operation of the internal combustion engine through heat conduction along the layer.

[0017] In a further advantageous development of the invention, the particulate filter has at least one projection, which is connected to the liquid-tight layer and inserted into at least one of the filter body elements in the direction of gravity. This optional configuration allows for faster heat transfer from the layer to at least one filter body element of the filter body arrangement that is geodetically lower than the liquid-tight layer. In other words, the at least one projection can be inserted downwards into one of the filter body elements in the direction of gravity. The at least one projection can, for example, be integrally connected to the liquid-tight layer.This can be advantageous for accelerating any thawing of the water-soaked and frozen filter body element, which is geodetically positioned lower than the liquid-tight layer, at ambient temperatures below the freezing point of water, as soon as the internal combustion engine is fired, i.e., operating with combustion of a fuel-air mixture. For example, it is conceivable that the at least one projection can be designed as a rib, which can be aligned in the longitudinal direction, preferably in the flow direction of the exhaust gas flow.

[0018] In a further advantageous development of the invention, the at least one liquid-tight layer and the filter body elements are formed from the same material, and the at least one liquid-tight layer has a lower porosity and / or a higher density than the filter body elements. The advantage here is that the liquid-tight layer and the filter body elements can thus have at least a similar thermal conductivity, whereby any undesirably high thermal stresses between the layer and the filter body elements can be avoided when the particulate filter heats up during operation. To make the layer liquid-tight, the layer can be more highly compressed and additionally or alternatively have fewer pores than the filter body elements. A second aspect of the invention relates to an exhaust gas aftertreatment device having at least one particulate filter according to the first aspect of the invention.This exhaust aftertreatment device enables particularly fail-safe and effective exhaust aftertreatment.

[0019] A third aspect of the invention relates to a particulate filter for a motor vehicle according to the first aspect of the invention and / or for an exhaust gas aftertreatment device according to the second aspect of the invention. This particulate filter enables exhaust gas aftertreatment to be performed reliably and effectively even if fluid penetrates the particulate filter.

[0020] The preferred embodiments and their advantages presented with respect to one of the aspects apply accordingly to the other aspects of the invention and vice versa.

[0021] The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0022] Further advantages, features and details of the invention emerge from the claims, the following description of preferred embodiments and from the drawings.

[0023] The invention is explained once again below using a specific exemplary embodiment. The sole figure (Fig. 1) shows a schematic representation of a motor vehicle with an internal combustion engine emitting an exhaust gas stream that is guided through an exhaust aftertreatment device whose particulate filter has at least one liquid-tight layer separating various filter body elements of a filter body arrangement of the particulate filter from one another.

[0024] Fig. 1 shows a motor vehicle K with an internal combustion engine 100 and an exhaust gas aftertreatment device 10 having a particulate filter 20. In addition to the particulate filter 20, the exhaust gas aftertreatment device 10 may comprise further exhaust gas aftertreatment units, for example at least one catalytic converter, which may be arranged downstream or upstream of the particulate filter. Apart from the particulate filter 20, no further exhaust gas aftertreatment units, such as the catalytic converter, are shown here.

[0025] The particulate filter 20 has a particulate filter housing 30 and a filter body assembly 40. The filter body assembly 40 is accommodated in the particulate filter housing 30 and serves to separate particles from an exhaust gas stream 12 that can be expelled by the internal combustion engine 100 and flows through the filter body assembly 40 during its intended use. The exhaust gas stream 12 is illustrated here by way of example by an arrow oriented in the longitudinal direction x of the particulate filter 20. For this reason, the arrow illustrating the exhaust gas stream 12 also represents this longitudinal direction x. A transverse direction y of the particulate filter 20 runs perpendicular to the plane of the drawing and thus perpendicular to the longitudinal direction x.

[0026] The filter body arrangement 40 can have a plurality of filter body elements, of which a first filter body element 42 and a second filter body element 44 are shown as examples. From Fig. 1, it can be seen that the two filter body elements 42, 44 are separated from one another by a liquid-tight, in particular watertight, layer 60 oriented in the longitudinal direction x of the particle filter 20. The liquid-tight layer 60, oriented perpendicular to the direction of gravity g, completely separates the first filter body element 42 and the second filter body element 44 both in the longitudinal direction x and in the transverse direction y.

[0027] The filter body arrangement 40 can have a plurality of filter body elements 42, 44, of which two of the filter body elements 42, 44 are separated from one another by at least one additional layer 62, 64, which is oriented parallel to the at least one liquid-tight layer 60 and is also liquid-tight. Fig. 1 indicates the first additional layer 62 and the second additional layer 64 in dashed lines. The watertight layer 60 and the likewise watertight additional layers 62, 64 each form a separating layer for different liquid levels h of a liquid 14 (here: water).

[0028] The liquid-tight layer 60 and the additional layers 62, 64 can be formed from a material with a higher thermal conductivity than the material of the filter body elements 42, 44. Accordingly, the liquid-tight layer 60, the additional layers 62, 64, and the filter body elements 42, 44 can be formed from a ceramic material and, in particular, can be designed as a ceramic brick. The liquid-tight layer 60 and the additional layers 62, 64 can have a lower porosity and, additionally or alternatively, a higher density than the filter body elements 42, 44.

[0029] Alternatively, the material of the liquid-tight layer 60 and the additional layers 62, 64 can also be metallic, thereby achieving improved thermal conductivity within the liquid-tight layer 60 and the additional layers 62, 64. In an optional embodiment, it is conceivable for the particulate filter 20 to have a plurality of projections 22, which are connected, for example, to the liquid-tight layer 60 and inserted into at least one of the filter body elements 42, 44 in the direction of gravity.

[0030] In summary, the invention addresses the problem that a water-soaked ceramic block of a particulate filter has several serious disadvantages. When soaked with liquid water, the exhaust backpressure is significantly increased during operation of the internal combustion engine, which can lead to false errors in various particulate filter diagnoses. At temperatures below the freezing point of water, i.e., below 0°C, and thus frozen water contained in the particulate filter, the exhaust backpressure increases massively again, until, in the worst case, the exhaust aftertreatment device can become completely blocked. This can result in a vehicle breakdown. In this case, the particulate filter can also be damaged by the extreme backpressure.

[0031] Due to the liquid-tight layer acting as a separating layer, at least part of the filter body assembly, for example, at least one of the ceramic blocks (filter body elements), no longer absorbs water, but rather only another ceramic block of the filter body assembly standing in the water. As a result, the particulate filter is no longer completely affected by the negative effects of water described above. While the saturated part can still freeze, this can be compensated for by the much larger dry area of ​​the block, thus preventing breakdowns and emissions deterioration.

[0032] 10 Exhaust aftertreatment device

[0033] 12 Exhaust gas flow

[0034] 14 Liquid

[0035] 20 particle filters

[0036] 22 lead

[0037] 30 particle filter housings

[0038] 40 Filter body arrangement

[0039] 42 Filter body element

[0040] 44 Filter body element

[0041] 60 shift

[0042] 62 first additional shift

[0043] 64 second additional shift

[0044] 100 Internal combustion engine g Direction of action h Fluid level

[0045] K Motor vehicle x Longitudinal direction y Transverse direction

Claims

Claims: Motor vehicle (K) with an internal combustion engine (100) and with an exhaust aftertreatment device (10), which includes a particulate filter (20), a particulate filter housing (30), and a filter body arrangement (40) designed for separating particles from an exhaust gas stream (12) emitted by the internal combustion engine and flowing through the filter body arrangement (40) during its intended use, and which is accommodated in the particulate filter housing (30), characterized in that the filter body arrangement (40) comprises filter body elements (42, 44) which are separated from one another by means of at least one liquid-tight layer (60) oriented at least substantially in the longitudinal direction (x) of the particulate filter (20). Motor vehicle (K) according to claim 1, characterized in that the at least one liquid-tight layer (60) is oriented at least substantially perpendicular to the direction of action (g) of gravity.Motor vehicle (K) according to claim 1 or 2, characterized in that the filter body arrangement (40) comprises a plurality of filter body elements (42, 44), two of which are separated from each other by at least one liquid-tight additional layer (62, 64) oriented parallel to the at least one liquid-tight layer (60). Motor vehicle (K) according to any one of the preceding claims, characterized in that the at least one liquid-tight layer (60) and the filter body elements (42, 44) are made of different materials. Motor vehicle (K) according to any one of the preceding claims, characterized in that. which at least one liquid-tight layer (60) is formed from a material with a higher thermal conductivity compared to the material of the filter body elements (42, 44).

6. Motor vehicle (K) according to one of claims 4 or 5, characterized in that the material of the at least one liquid-tight layer (60) is metallic.

7. Motor vehicle (K) according to one of claims 4 to 6, characterized in that the particulate filter (20) has at least one projection (22) which is connected to the liquid-tight layer (60) and is inserted in the direction of action (g) of gravity into at least one of the filter body elements (42, 44).

8. Motor vehicle (K) according to one of claims 1 to 3, characterized in that the at least one liquid-tight layer (60) and the filter body elements (42, 44) are formed from the same material and the at least one liquid-tight layer (60) has a lower porosity and / or a higher density than the filter body elements (42, 44).

9. Exhaust aftertreatment device (10) for an internal combustion engine (100) with at least one particulate filter (20) according to one of claims 1 to 8.

10. Particle filter (20) for a motor vehicle (K) according to one of claims 1 to 8 and / or for an exhaust aftertreatment device (10) according to claim 9.

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