DE102006016890A1 - Element for filtering exhaust gases from diesel engine comprises one channel of first group and two channels of second group having cross-sectional areas forming parallelogram with four corners and two pairs of adjacent sides - Google Patents

Abstract

A filter element comprises one channel (28) of a first group of channels and two channels (30) of a second group of channels that have cross-sectional areas that form a parallelogram with four corners (34) and two pairs of adjacent sides. A first length (38) of a pair of adjacent sides and an additional filter wall (36) define an outlet channel. The cross-sectional area of each channel of the second group of channels comprises a triangle and a polygon. Preferred Features: The filter element is made by extrusion of a ceramic or glass-ceramic material, especially cordierite or silicon carbide, or sintered metal.

Description

State of technology

The The invention relates to a filter element, in particular for an exhaust system an internal combustion engine, according to the preamble of claim 1.

From the EP 1 502 640 A1 a filter element known with an entrance surface and with an exit surface, with a plurality of inlet channels and with a plurality of outlet channels known, wherein the inlet channels have a hexagonal cross-section and the outlet channels have a square or diamond-shaped cross section, and wherein the inlet channels and the outlet channels through a Filter wall are separated from an open-cell material.

there flows the exhaust gas to be cleaned through the filter walls between the inlet channels and the outlet channels therethrough. In the known filter element are deposited over time at the upstream located surface the filter wall soot particles from. These soot particles to lead to a reduction in permeability the filter wall and as a result to an increase in the pressure drop, the Passage of the gas flow through the filter wall occurs. Corresponding elevated the so-called "exhaust backpressure". exceeds this one particular value, the filter is regenerated by the separated soot particles to be burned. For this purpose, the temperature of the exhaust gas, which passed through the filter device increases, which in turn through the Injection of additional Fuel is effected.

task It is the object of the present invention to provide the additional fuel needed for regeneration to reduce the filter device.

epiphany the invention

The underlying the invention is in a filter element, in particular for filtering exhaust gases of a diesel internal combustion engine, with an entrance area and an exit surface, with a variety of entry channels and with a variety of exit channels, the entrance channels and the exit channels through filter walls are separated from an open-pore material, solved by that the cross-sectional areas from an inlet channel and two outlet channels with a parallelogram form four corners and two pairs of neighbor sides, and that one first leg of pairs of neighbors and an additional one Filter wall define an outlet channel.

Advantages of invention

The inventive geometry the cross sections of inlet channels and outlet channels allowed it, within very wide limits, the ratio of the cross-sectional areas of the one inlet channel to the two outlet channels in wide To vary borders. The same applies to the ratio of the surfaces of the Filter walls, which limit the inlet channel and the surfaces of the filter walls, which the exit channels limit.

The said conditions are important parameters, with the help of which the number and intensity of the filter devices can be controlled. Furthermore, the geometry according to the invention allows the cross sections of inlet channels and outlet channels the Structure of a filter element that is relatively insensitive to thermal Is voltages that result from locally different temperature loads.

Of Another is the design of the invention the cross sections of inlet channels and outlet channels good mastery of production technology, which is particularly true in the cost-effective production of filtering devices having a plurality of small inlet channels and even smaller outlet channels of great economic importance.

By the inventive arrangement an additional one Filter wall, which two adjacent sides of the parallelogram with each other connects each side of the parallelogram into a first leg and divided into a second leg.

A particularly advantageous embodiment of the filter device according to the invention provides that the first leg and the second leg of the Pages of the parallelogram are the same length. This will ensure that all entrance channels a filter device according to the invention on all sides of outlet channels be limited. This increases the effectiveness the filter device according to the invention.

A first, particularly simple embodiment sees the filter device according to the invention before that the cross-sectional area Each outlet channel has the shape of a triangle.

Further advantageous embodiments of the filter device according to the invention provide that the cross-sectional area of each outlet channel is composed of a triangle and a polygon. This means nothing else than that the additional filter wall in cross section is not straight, but composed of different straight or curved sections. Close it two adjoining sections of the additional filter wall at an angle with each other.

Thereby Firstly, it becomes the surface the additional Filter wall enlarges what in an elevated Filter performance or a reduced exhaust back pressure of the filter device according to the invention reflected. Furthermore becomes the additional filter wall, since it no longer runs straight, "softer", so the sensitivity the filter device according to the invention across from thermal stress or sudden temperature changes is reduced. This will ensure the functional safety and service life the filter device according to the invention significantly increased.

alternative Is it possible, that the polygon, which forms part of the cross-sectional area of each Exit channel forms, is a concave or a convex polygon. Convex is a polygon in which each link two arbitrary corners of the polygon in its interior verläft. It's why no angle greater than 180 ° is. A polygon where the link is at least two points of the polygon does not run in its interior, points at least one angle exceeding 180 °, and is related referred to with the invention as a concave polygon. This concave Polygon has at least one so-called re-entrant corner. The terms concave and convex polygon are used in conjunction with the following Figures will be explained in more detail.

The from the cross-sectional areas formed by an inlet channel and two outlet channels parallelogram can be a square, a rectangle, a rhombus (rhombus) or a rhomboid be. The selection of one of these parallelograms in the construction of the filter element according to the invention depends on the circumstances of the individual case.

It has further proven to be advantageous if at least the upstream surface the filter walls having a catalytic coating. Due to the large surface is the catalytic effect, for example during regeneration reinforced the filter element.

Especially it is advantageous if at least the upstream surface the filter wall has a catalytic coating. By the size surface becomes the catalytic effect, for example, in a regeneration the filter device reinforced.

The filter elements according to the invention can advantageously by extruding a ceramic material, preferably cordierite or silicon carbide, or made of sintered metal become.

alternative it is also possible the filter element of a plurality of stacked layers preformed flat materials.

Further Advantages and advantageous embodiments of the invention are the subsequent drawing, the description and the claims can be removed. All described in the drawing, the description and the claims Features can both individually and in any combination with each other invention essential be.

drawings

It demonstrate:

1 a schematic representation of an internal combustion engine with an exhaust gas aftertreatment device according to the invention;

2 a filter element according to the invention in longitudinal section and

3 to 8th Cross sections through embodiments of inventive filter elements.

description the embodiments

In 1 an internal combustion engine carries the reference number 10 , The exhaust gases are via an exhaust pipe 12 derived in which a filter device 14 is arranged. With this soot particles from the exhaust pipe 12 filtered exhaust gas filtered out. This is particularly necessary in diesel internal combustion engines to comply with legal requirements.

The filter device 14 includes a cylindrical housing 16 in which a rotationally symmetrical in the present embodiment, a total also cylindrical filter element 18 is arranged. Of course, the invention is not limited to the geometry. The filter elements can also be oval or rectangular in cross-section, for example.

In 2 is a cross section through a filter element according to the invention 18 shown. The filter element 18 For example, it can be made as an extruded molded article of a ceramic material such as cordierite.

The filter element 18 will be in the direction of the arrows 20 flows through not shown exhaust gas. An entrance area has in 2 the reference number 22 while an exit surface in 2 the Be reference numbers 24 Has. Parallel to a longitudinal axis 26 of the filter element 18 run several inlet channels 28 in alternation with outlet channels 30 , The entrance channels 28 are at the exit surface 24 locked. The sealing plugs are in 2 shown without reference number. In contrast, the exit channels 30 at the exit surface 24 open and in the area of the entrance area 22 locked.

The flow path of the unpurified exhaust gas thus leads into one of the inlet channels 28 and from there through a filter wall 31 in one of the exit channels 30 , This is exemplified by arrows 32 shown.

By reversing the flow direction of the exhaust gas, the area becomes 24 to the entrance area and the area 22 to the exit surface. This will make the channels 28 to exit channels, while the channels 30 become entrance channels. The reversal of the flow direction of the exhaust gas can be achieved by changing the installation position of the filter element 18 in the case 16 be achieved in the simplest way. In the exemplary embodiments described below, for the sake of clarity, only one flow direction and, as a consequence, a function of the channels will always be used 28 and 30 gone out, though the function of the channels 28 and 30 by turning the filter element 18 in the case 16 can also be changed.

In 3 are cross sections of a first embodiment of a filter element according to the invention 18 shown. In the 3a is a "basic element" consisting of an inlet channel 28 and two exit channels 30 , shown enlarged. The cross-sectional areas of the two outlet channels 30 and one entry channel 28 complement each other in this embodiment to a square. The square is a special form of a parallelogram, where the parallelogram is for example a square, a rectangle, a rhombus or a rhomboid. Both the square and the rectangle include two adjacent sides each at an angle of 90 °. If the angles between two adjacent sides are not 90 °, the square turns into a rhombus and the rectangle into a rhomboid.

In the filter element according to the invention 18 each form two pairs of filter walls 31 a corner 34 , The corners 34 lie opposite each other. Between the pairs of filter walls 31 each is an additional filter wall 36 intended. The additional filter walls 36 divide the filter walls 31 in a first leg 38 and a second leg 40 , The additional filter wall 36 as well as the first sections 38 the filter walls 31 limit the exit channels 30 , Because of the symmetry of the exit channels 30 the reference numerals are only attached to an outlet channel. In the embodiment according to 3 is has the additional filter wall 36 in the middle a kink 42 on. The kink 42 causes the cross-section of the inlet channel 28 becomes a concave polygon with eight corners. Concave is the polygon because of the connecting line 43 between two corners of the polygon outside the entrance channel 28 runs.

This means that the cross-sectional area of the outlet channels 30 is formed of two with their bases superimposed triangles. In other words, in this embodiment, the exit channels 30 in cross-section the shape of a kite. The cross sections of the outlet channels 30 form a convex polygon with four corners, which is called a dragon.

If you now follow the squares according to 3a consisting of an inlet channel 28 and two exit channels 30 , juxtaposed, results in the 3b illustrated structure. This structure is a partial section through a filter element according to the invention 18 ,

As in the embodiment according to 3 the first leg 38 and the second leg 40 are the same length, the entrance channels 28 on all sides of outlet channels 30 locked in. This is desirable because only by changing the exhaust gases from an inlet channel 28 in an exit channel 30 the desired filter effect can be achieved. For the sake of clarity are in the 3b only the reference numerals of an entrance channel 28 and this entry channel 28 surrounding outlet channels 30 entered.

4 shows a further embodiment of a filter element according to the invention 18 , In the embodiment according to 4 sets the cross section of the outlet channels 30 from a triangle 44 and a trapeze attached to it 46 together. This "basic element", consisting of an inlet channel 28 with a tenon-shaped cross-section and two outlet channels 30 each with a pentagonal cross section, in turn, gives a square cross section of the basic element. In the embodiment according to 4 has the entrance channel 28 in cross-section the shape of a concave polygon with ten corners.

In the 4b are several basic elements according to 4a arranged side by side.

The 4c shows an alternative arrangement of the square basic elements. In the arrangement according to 4b are the longitudinal axes of the cross sections of the inlet channels 28 arranged parallel to each other, while in the embodiment according to 4c partially offset by 90 ° to each other are arranged. Of course, it is also possible to provide in all other embodiments, the rotation of individual modules relative to the other by 90 °.

In 5 is another example of a filter element according to the invention 18 shown. In this embodiment, the exit channels 30 in cross-section the shape of a triangle 44 with an attached concave polygon with five corners (no reference) on. In this embodiment, the cross section of the inlet channel 28 the shape of a dodecagonal concave polygon.

In 5b is again the juxtaposition of several basic elements according to 6a shown. Again, as already mentioned, the basic elements can be arranged rotated relative to each other by 90 °.

In 6a a further embodiment of a filter element according to the invention is shown. In this embodiment, the basic element, consisting of two outlet channels 30 and an entrance channel 28 , the shape of a rectangle.

In the embodiment according to 7 complement the cross-sectional areas of the outlet channels 30 and the associated entrance channel 28 an element to a rhomboid. Of course, even with a rectangular cross section of the basic elements and rhombusförmigem cross section of the basic elements based on the 3 to 6 explained cross sections of the outlet channels 30 will be realized.

With reference to the described embodiments of inventive filter elements 18 It is clear that by the geometries according to the invention of the cross-sectional areas of inlet channels 28 and exit channels 30 the ratio of the cross-sectional areas of inlet channels 28 to the cross-sectional areas of the outlet channels 30 can be varied within very wide limits. Also, the relationship between the surfaces of the inlet channels 28 and the exit channels 30 can be adjusted by the inventively claimed geometries within wide limits according to the requirements of the case.

The stiffness of the filter element or its elasticity and thus insensitivity to temperature stresses or rapid temperature changes can be achieved by the geometry of the inlet channels according to the invention 28 and the exit channels 30 to be influenced.

In the in the 3 to 6 Illustrated embodiments are in a basic element each an inlet channel 20 and two exit channels 30 intended. Of course it is also possible, the filter element 18 turn around so that with the

Claims (12)

Filter element ( 18 ), in particular for filtering exhaust gases of a diesel internal combustion engine, having an entry surface ( 22 ) and with an exit surface ( 24 ), with a first group of channels ( 28 ) and with a second group of channels ( 30 ), where the first group of channels ( 28 ) and the second group of channels ( 30 ) through filter walls ( 31 ) are separated from an open-pore material, characterized in that the cross-sectional areas of a channel ( 28 ) of the first group of channels and two channels of the second group of channels ( 30 ) a parallelogram with four corners ( 34 ) and two pairs of neighbor sides, and that a first leg ( 38 ) of the pairs of neighboring sides and an additional filter wall ( 36 ) an exit channel ( 30 ) and that the cross-sectional area of each channel ( 30 ) of the second group of channels ( 30 ) of a triangle and a polygon ( 46 ). Filter element ( 18 ) according to claim 1, characterized in that each side of the parallelogram of the additional filter wall ( 36 ) into a first leg ( 38 ) and in a second leg ( 40 ) is divided. Filter element ( 18 ) according to claim 2, characterized in that the first leg ( 38 ) and the second leg ( 40 ) of one side of the parallelogram are the same length. Filter element ( 18 ) according to one of the preceding claims, characterized in that the polygon ( 46 ) is a convex or a concave polygon. Filter element ( 18 ) according to one of the preceding claims, characterized in that the parallelogram is a square, a rectangle, a rhombus (rhombus) or a rhomboid. Filter element ( 18 ) according to one of the preceding claims, characterized in that at least the upstream surface of the filter wall has a catalytic coating. Filter element ( 18 ) according to one of the preceding claims, characterized in that the filter element ( 18 ) is produced by extrusion. Filter element ( 18 ) according to one of the preceding claims, characterized in that the filter element ( 18 ) is made of a ceramic or a glass-ceramic material, in particular of cordierite or of silicon carbide. Filter element ( 18 ) according to one of the preceding claims, characterized in that the filter element ( 18 ) is made of sintered metal. Filter element ( 18 ) according to one of the preceding claims, characterized in that the first group of channels ( 28 ) is formed as inlet channels, and that the second group of channels ( 30 ) is formed as outlet channels. Filter element ( 18 ) according to one of claims 1 to 9, characterized in that the first group of channels ( 28 ) is formed as outlet channels, and that the second group of channels ( 30 ) is designed as inlet channels. Filter element according to one of the preceding claims, characterized in that the inlet channels ( 28 ) at the entrance surface ( 22 ) and at the exit surface ( 24 ) are closed, and that the outlet channels ( 30 ) at the entrance surface ( 22 ) are closed and at the exit surface ( 24 ) end up.