An automobile equipped with an internal combustion engine and an exhaust gas aftertreatment device, an exhaust gas aftertreatment device for an internal combustion engine, and a particulate filter

Abstract

The present invention relates to a motor vehicle (K) comprising an internal combustion engine (100) and an exhaust gas aftertreatment device (10), wherein the exhaust gas aftertreatment device (10) has a particulate filter (20) comprising a particulate filter housing (30) and a filter body assembly (40), the filter body assembly (40) being formed to separate particles from a flowing exhaust gas stream (12) which may be discharged by the internal combustion engine during normal use of the filter body assembly (40) and being accommodated within the particulate filter housing (30). The filter body assembly (40) has filter body elements (42, 44), which are separated from each other by at least one liquid-impermeable layer (60) oriented at least substantially in the longitudinal direction (x) of the particulate filter (20). Further aspects of the present invention relate to an exhaust gas aftertreatment device (10) for an internal combustion engine (100) and to a particulate filter (20).

Description

Technical Field

[0001] The present invention relates to a motor vehicle comprising an internal combustion engine and an exhaust gas aftertreatment device, the exhaust gas aftertreatment device having a particulate filter comprising a particulate filter housing and a filter body assembly, the filter body assembly being formed to separate particles from a flowing exhaust gas stream that may be discharged by the internal combustion engine during normal use of the filter body assembly and being housed within the particulate filter housing. Further aspects of the present invention relate to an exhaust gas aftertreatment device for an internal combustion engine and a particulate filter.

Background Art

[0002] Diesel particulate filters have long been used for the aftertreatment of exhaust gases from diesel engines, but nowadays the use of gasoline particulate filters is also increasing. This is due to the increasingly stringent exhaust gas regulations, in order to further reduce the proportion of soot particles in the exhaust gas generated by gasoline engines, which were already originally present in trace amounts compared to diesel engines. A gasoline particulate filter (GPF) can for example have a porous ceramic stone, and its porous surface can reliably filter soot particles from the exhaust gas and guarantee compliance with today's emission regulations anywhere in the world. As each regulation becomes more stringent, the requirements for the collection efficiency (FE) of the particulate filter also increase. In this situation, on the structural side of the particulate filter, it can be addressed by making the structure of the ceramic stone finer and more porous step by step.

[0003] From Patent Document 1, a filter for filtering the exhaust gas of an internal combustion engine on the inlet side and the outlet side is known. This filter is formed from a plurality of fleece layers and has gas-impermeable end regions formed by smooth strips at the end portions on the inlet side and the outlet side, respectively. The fleece layers have strips of a pleated layer on at least one side, and these are arranged along the smooth strips. Two adjacent fleece layers are spaced apart from each other on the inlet side or the outlet side. On the inlet side and the outlet side alternately, two smooth belt strips adjacent to each other directly are airtightly connected to each other.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem of the present invention is to provide an automobile equipped with an internal combustion engine, which can perform fail-safe and effective exhaust gas aftertreatment. Further, the problem of the present invention is to provide a corresponding exhaust gas aftertreatment device for an internal combustion engine and a particulate filter.

Means for Solving the Problems

[0006] This problem is solved by an automobile having the features of claim 1, an exhaust gas aftertreatment device having the features of claim 9, and a particulate filter according to claim 10. Advantageous embodiments with useful development forms of the present invention are described in the dependent claims.

[0007] A first aspect of the present invention is an automobile including an internal combustion engine and an exhaust gas aftertreatment device, where the exhaust gas aftertreatment device has a particulate filter including a particulate filter housing and a filter body assembly. The filter body assembly is configured to separate particles from a flowing exhaust gas stream that may be discharged by the internal combustion engine during normal use of the filter body assembly and is housed within the particulate filter housing. That is, the filter body assembly as a whole can be used to filter particles from the exhaust gas stream passing through the filter body assembly during operation of the internal combustion engine, particularly during exhaust gas aftertreatment by the filter body assembly, during normal use of the filter body assembly.

[0008] According to the present invention, the filter body assembly has filter body elements which are separated from each other by at least one liquid-impermeable layer, in particular a waterproof layer, which is at least substantially longitudinally oriented with respect to the particulate filter. This has the advantage that, by means of the liquid-impermeable layer, which can also be referred to as a separating layer, when there is liquid in contact with the filter body assembly in the exhaust gas aftertreatment device, the entire filter body assembly cannot inadvertently suck in and become completely filled with liquid, in particular water (suction saturation). Inadvertent suction saturation can lead to an unacceptably high exhaust gas backpressure when the exhaust gas flow passes through the filter body assembly, which can interfere with the operation of the internal combustion engine. Preferably, at least one liquid-impermeable layer extends between two housing parts of the particulate filter housing which are opposite one another, and the housing parts which are opposite one another are connected to one another by this liquid-impermeable layer, so that the filter body elements can be completely separated from one another not only longitudinally but also transversely. This layer can in particular be oriented parallel to a plane extending in the longitudinal and transverse directions of the particulate filter. The longitudinal direction may preferably correspond to the direction of flow of the exhaust gas flow. The exhaust gas flow can pass through the filter body elements in the direction of flow of the exhaust gas during the original use of the particulate filter.

[0009] The present invention is based on the finding that a filter body element, which is usually made of a ceramic material, has a microstructure, in particular pores, which enables it to filter particles from the exhaust gas flow, while in particular the capillary effect (by which liquid can be conveyed through the filter body element even against the direction of action of gravity) promotes the suction saturation of one of the filter body elements in some cases. If there is a sufficiently large amount of liquid, in particular water, in contact with the filter body element, in the worst case, the entire filter body element may become suction saturated. If a particulate filter has associated individual filter body elements, the filter body assembly may become completely saturated. Water as a liquid is a by-product of the combustion of the fuel-air mixture during the combustion operation of an internal combustion engine. Above all, when the internal combustion engine is operated at low load for a long time, a large amount of water may accumulate in the exhaust gas aftertreatment device. Furthermore, not only is water generated as a by-product of combustion, but water may also enter the exhaust gas aftertreatment device of the motor vehicle from the outside. This can occur, for example, during heavy rain or when passing through a car wash. Thus, for example, in the worst case, several litres of liquid water may accumulate in the final pot of the exhaust gas aftertreatment device and at other geodetically low positions of the exhaust gas aftertreatment device, which may overflow into the particulate filter due to the movement of the motor vehicle, i.e., due to the dynamic movement during driving. Due to the porous structure of the filter body element, even if only the lower part of the filter body element is in water in the direction of action of gravity, the filter body element may, in some cases, absorb water abundantly throughout. This risk of suction saturation is particularly present when using the particulate filter as an underbody particulate filter. There are several serious problems with a filter body element infiltrated with water (which can also be called a GPF stone when the particulate filter is formed as a gasoline particulate filter). The infiltration of liquid water causes the back pressure of the exhaust gas to increase significantly during the operation of the internal combustion engine due to the suction-saturated filter body element, which may lead to various malfunctions found in various diagnostics regarding the particulate filter during the operation of the internal combustion engine.At sub-zero temperatures, i.e., temperatures below 0°C, the water absorbed within the filter body element may freeze, which may result in a significant increase in the back pressure of the exhaust gas, leading to a possible complete blockage of the exhaust gas aftertreatment device. This may cause the vehicle to break down. In this case, the particulate filter may be damaged by the extreme back pressure of the exhaust gas. The present invention addresses this by enabling the suction saturation of all filter body elements to be blocked by a liquid-impermeable layer, thereby enabling the suction saturation of at least one of the filter body elements to be blocked by the liquid-impermeable layer, and ensuring that the exhaust gas aftertreatment device can function even when there is liquid present in the exhaust gas aftertreatment device and the temperature drops below its freezing point. This enables fail-safe and effective exhaust gas aftertreatment to be carried out even under such adverse conditions.

[0010] In an advantageous development of the invention, at least one liquid-impermeable layer is oriented at least approximately perpendicular to the direction of action of gravity. This is advantageous as it prevents the above-mentioned layer from occupying an unnecessarily large amount of the installation space inside the particulate filter housing, and the liquid column, especially the water column, generated in the exhaust gas aftertreatment device from inadvertently entering all the filter body elements. At least one layer may be arranged in the filter body assembly to form a layer of the particulate filter. The expression "oriented at least approximately perpendicular to the direction of action of gravity" may be understood in the context of the present disclosure as meaning that at least one layer can be located within a certain plane, and the normal vector of that plane can be oriented parallel to the direction of action of gravity. However, the expression "oriented approximately perpendicular to the direction of action of gravity" may be understood in the context of the present disclosure as meaning that the above-mentioned normal vector and the direction of action of gravity form an angle α corresponding to any of the angular values of, for example, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°.

[0011] In yet another advantageous development of the invention, the filter body assembly has a plurality of filter body elements, two of which are separated from each other by at least one additional liquid-impermeable layer oriented parallel to at least one liquid-impermeable layer. Thereby, in an advantageous manner, when the liquid level in the exhaust gas aftertreatment device is low, the filter body assembly can also be suction-saturated with liquid in only a small volume.

[0012] The following example should be helpful for understanding: For example, if the particulate filter has two additional layers, both of these additional layers together with the above-mentioned layer can jointly and liquid-tightly separate the four filter body elements of the filter body assembly from each other. In that case, they can be arranged in the following order in the direction of the action of gravity: first filter body element - liquid-impermeable layer - second filter body element - first additional layer - third filter body element - second additional layer - fourth filter body element.

[0013] In connection with this example, if the second additional layer is, for example, above the liquid level in terms of height, only the lowest one in terms of height among the four filter body elements (the fourth filter body element in this example) will be saturated, while effectively preventing the three filter body elements (the first, second, and third filter body elements) arranged above the fourth filter body element in terms of height from being suction-saturated. The liquid-impermeable layer and the additional layer can together form a plurality of separation layers for different liquid levels.

[0014] In yet another advantageous development of the invention, at least one liquid-impermeable layer and the filter body element are formed from different materials from each other. Thereby, for example, a liquid-tight connection between the particulate filter housing and the liquid-impermeable layer is facilitated. Then, the above-mentioned layer and the particulate filter housing can be formed, for example, from the same metallic material and can, for example, be materially bonded to each other.

[0015] In yet another advantageous development of the present invention, at least one liquid-impermeable layer is formed from a material having a higher thermal conductivity than the material of the filter body element. This makes it easier for heat to be quickly dispersed along the filter body assembly, and as a result, the thermal stress can be reduced.

[0016] In yet another advantageous development of the present invention, the material of at least one liquid-impermeable layer is metallic. This can, in an advantageous manner, result in the effect that heat is more quickly dispersed along the filter body element within the particulate filter housing. In other words, the liquid-impermeable layer can, as a result, be formed from a metallic material, which can contribute to better heating of the particulate filter by heat conduction along the layer during operation of an internal combustion engine.

[0017] In yet another advantageous development of the present invention, the particulate filter has at least one protrusion, which is coupled to the liquid-impermeable layer and is inserted into at least one filter body element in the direction of the action of gravity. This optional embodiment enables more rapid heat transfer from the above layer to at least one filter body element of the filter body assembly that is positioned at a height lower than the liquid-impermeable layer. In other words, at least one protrusion can be inserted downward in the direction of gravity into one of the filter body elements. The at least one protrusion can, for example, be integrally coupled to the liquid-impermeable layer. This can be advantageous in that it can, in some cases, accelerate the thawing of a filter body element that is arranged at a height lower than the liquid-impermeable layer and has sucked in and frozen water when the internal combustion engine ignites and operates by burning a mixture of fuel and air at an external temperature below the freezing point of water. For example, it is considered that the at least one protrusion can be formed as a rib that can be aligned in the longitudinal direction, more preferably in the direction of the flow of the exhaust gas stream.

[0018] In yet another advantageous development of the invention, at least one liquid-impermeable layer and the filter body element are formed from the same material, and the at least one liquid-impermeable layer has a lower porosity and / or a higher density than the filter body element. In this case, the liquid-impermeable layer and the filter body element can as a result have at least an equivalent thermal conductivity, whereby, when heating the particulate filter during use, the advantage is that thermal stresses that could undesirably increase between the abovementioned layer and the filter body element can be avoided. In order to make the abovementioned layer liquid-tight, the abovementioned layer can be made even denser and, additionally or alternatively, can have fewer pores than the filter body element.

[0019] A second aspect of the invention relates to an exhaust gas aftertreatment device comprising at least one particulate filter according to the first aspect of the invention. In this exhaust gas aftertreatment device, in particular, fail-safe and effective exhaust gas aftertreatment can be carried out.

[0020] 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. With this particulate filter, even if liquid were to penetrate into the particulate filter, fail-safe and effective exhaust gas aftertreatment can be carried out.

[0021] The preferred embodiments and their advantages presented with respect to one aspect are correspondingly applicable to the other aspects of the invention and vice versa.

[0022] The features and combinations of features shown in the above description and the features and combinations of features listed below in the description of the drawings and / or shown only in the drawings are usable not only in the individually described combinations but also in other combinations or alone without departing from the scope of the invention.

[0023] Still other advantages, features, and details of the present invention will become apparent from the claims, the following description of the preferred embodiments, and the drawings.

[0024] Hereinafter, the present invention will be described again based on specific examples.

Brief Description of the Drawings

[0025]

Figure 1

Modes for Carrying Out the Invention

[0026] Figure 1 shows an automobile K equipped 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 can also have other exhaust gas aftertreatment units that can be connected downstream or upstream of the particulate filter, such as, for example, at least one catalytic converter. In addition to the particulate filter 20, other exhaust gas aftertreatment units, such as catalytic converters, are not shown here.

[0027] The particulate filter 20 has a particulate filter housing 30 and a filter body assembly 40. The filter body assembly 40 is housed within the particulate filter housing 30 and is used to separate particles from the flowing exhaust gas stream 12 that may be discharged by the internal combustion engine 100 during its normal use. The exhaust gas stream 12 is represented, in this example, by an arrow pointing in the longitudinal direction x of the particulate filter 20 by way of example. For this reason, the arrow representing the exhaust gas stream 12 also points to this longitudinal direction x. The lateral direction y of the particulate filter 20 extends perpendicular to the plane of the paper and is thus perpendicular to the longitudinal direction x.

[0028] The filter body assembly 40 can have a plurality of filter body elements, among which the first filter body element 42 and the second filter body element 44 are illustrated. From FIG. 1, it can be seen that these two filter body elements 42, 44 are separated from each other by a liquid-impermeable layer, in particular a waterproof layer 60, oriented in the longitudinal direction x of the particulate filter 20. The liquid-tight layer 60, oriented perpendicular to the direction of action g of gravity, here completely separates the first filter body element 42 and the second filter body element 44 in both the longitudinal direction x and the lateral direction y.

[0029] The filter body assembly 40 can have a plurality of filter body elements 42, 44, each of the two filter body elements 42, 44 among them being separated from each other by at least one additional layer 62, 64, also liquid-impermeable, oriented parallel to at least one liquid-impermeable layer 60. FIG. 1 represents the first additional layer 62 and the second additional layer 64 by dashed lines. The waterproof layer 60 and the additional layers 62, 64, also waterproof, each form a separation layer for various liquid levels h of the liquid 14 (here water).

[0030] The liquid-impermeable layer 60 and the additional layers 62, 64 can be formed from a material having a higher thermal conductivity than the material of the filter body elements 42, 44. Thus, the liquid-impermeable layer 60, the additional layers 62, 64 and the filter body elements 42, 44 can be formed from a ceramic material, in particular configured as a ceramic stone. The liquid-impermeable layer 60 and the additional layers 62, 64 can have a lower porosity than the filter body elements 42, 44 and, additionally or alternatively, can have a high density.

[0031] Alternatively, the material of the liquid-impermeable layer 60 and the additional layers 62, 64 can be metallic, thereby improving the internal thermal conductivity of the liquid-impermeable layer 60 and the additional layers 62, 64. In an optional embodiment, it is conceivable that the particulate filter 20 has a plurality of protrusions 22, which are, for example, coupled to the liquid-impermeable layer 60 and inserted into at least one of the filter body elements 42, 44 in the direction of action g of gravity.

[0032] Generally, the present invention addresses the problem that the ceramic stones of particulate filters infiltrated with water have several significant drawbacks. When liquid water infiltrates, the back pressure of the exhaust gas increases significantly during the operation of the internal combustion engine, and malfunctions that appear in various particulate filter diagnostics can occur. At sub-zero temperatures, i.e., temperatures below 0 °C, the water contained in the particulate filter thereby freezes, and the back pressure of the exhaust gas also rises significantly, and in the worst case, the exhaust gas aftertreatment device may become completely clogged. This can result in a malfunction of the motor vehicle. In this case, the particulate filter may also be damaged by extreme back pressure.

[0033] The liquid-impermeable layer that functions as a separation layer ensures that at least a part of the filter body assembly, for example, at least one of the ceramic stones (filter body elements), no longer sucks in water completely, and only the other ceramic stones of the filter body assembly in the water suck in water. As a result, the particulate filter is no longer affected by the adverse effects of water as described above. At this time, although the completely immersed part may still freeze, it can be offset by a much larger dry stone area than that part, so that failures and deterioration of the exhaust gas can be prevented.

Description of Signs

[0034] 10 Exhaust gas post-treatment device 12 Exhaust gas flow 14 Liquid 20 Particulate filter 22 Protrusion 30 Particulate filter housing 40 Filter body assembly 42 Filter body element 44 Filter body element 60 Layer 62 First additional layer 64 Second additional layer 100 Internal combustion engine g Direction of action h Liquid level K Automobile x Longitudinal direction y Lateral direction

Claims

1. An automobile (K) comprising an internal combustion engine (100) and an exhaust gas aftertreatment device (10), wherein the exhaust gas aftertreatment device (10) has a particulate filter (20) comprising a particulate filter housing (30) and a filter body assembly (40), wherein the filter body assembly (40) is formed to separate particles from a through-flow of exhaust gas (12) that may be discharged by the internal combustion engine during the intended use of the filter body assembly (40) and is housed within the particulate filter housing (30), The filter assembly (40) has filter elements (42, 44), which are separated from each other by at least one impermeable layer (60) oriented at least substantially in the longitudinal direction (x) of the particulate filter (20). An automobile characterized by the following features.

2. In the automobile (K) described in claim 1, At least one of the impermeable layers (60) is oriented at least substantially perpendicular to the direction of gravity (g). An automobile characterized by the following features.

3. In the automobile (K) according to claim 1 or 2, The filter assembly (40) has a plurality of filter elements (42, 44), and each of two of the filter elements (42, 44) is separated from each other by at least one additional layer (62, 64) which is also impermeable and oriented parallel to at least one of the impermeable layers (60). An automobile characterized by the following features.

4. In the automobile (K) described in claim 1 At least one of the impermeable layers (60) and the filter elements (42, 44) are formed from different materials. An automobile characterized by the following features.

5. In the automobile (K) described in claim 1 At least one of the impermeable layers (60) is formed from a material with a higher thermal conductivity than the material of the filter elements (42, 44). An automobile characterized by the following features.

6. In the automobile (K) described in claim 4, The material of at least one of the impermeable layers (60) is metallic. An automobile characterized by the following features.

7. In the automobile (K) according to any one of claims 4 to 6, The particulate filter (20) has at least one protrusion (22), which is coupled to the impermeable layer (60) and inserted into at least one of the filter body elements (42, 44) in the direction of gravity (g). An automobile characterized by the following features.

8. In the automobile (K) according to claim 1 or 2, At least one of the impermeable layers (60) and the filter elements (42, 44) are formed from the same material, and at least one of the impermeable layers (60) has a lower porosity and / or a higher density than the filter elements (42, 44). An automobile characterized by the following features.

9. An exhaust gas aftertreatment device (10) for an internal combustion engine (100) comprising at least one particulate filter (20) according to claim 1 or 2.

10. A particulate filter (20) for an automobile (K) according to claim 1 or 2.

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