SE537008C2 - Device for cleaning a particle filter - Google Patents

Abstract

The invention relates to a device (1) intended for use in cleaning a particle filter (2) in a muffler (3) for an internal combustion engine. The device (1) comprises a disc unit (4) adapted to be arranged in connection with a mounting opening (5) for the particle filter (2) in the muffler (3) for partially shielding an outlet end (6) of the particle filter (2). The disc unit (4) is designed as a mixer disc which has a single opening (7) intended to let air through during cleaning by a suction system (20) connected to the muffler (3) sucking air through the opening (7) and backwards through the particle filter (2). (Fig. 2)

Description

25 30 537 008 trucks with diesel engines powered by alternative fuels, replacement or cleaning of the particulate filter may need to be performed at even shorter intervals.

It is important that the particle filter can be easily replaced or cleaned.

Due to relatively high costs for particle filters, there are today replacement systems, where a particle filter is handed in for cleaning and replaced with a cleaned replacement filter. The problem still remains that the muffler, or at least the particle filter, needs to be dismantled to replace the existing particle filter with a replacement filter. In addition, the solution with replacement systems is often expensive and time-consuming because usually a number of different parties are involved in the handling of the replacement filter.

A significant problem identified with today's replacement of particle filters is thus the difficulty of disassembling the muffler to disassemble the particle filter, and / or to disassemble the particle filter itself. Another problem identified in connection with this is to be able to clean particle files carefully and easily, and without the need to disassemble the particle filter from the muffler.

Document WO 2008/054262 A1 describes an example of how a particle filter in a muffler can be cleaned without the filter having to be removed from the muffler.

As an example of the prior art, reference is also made to US 7716922 which describes how purification of a particle filter can take place on site in a vehicle.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solution for cleaning a particle filter arranged in a muffler without the muffler, and thus not the particle filter, having to be dismantled from its location.

A further object of the present invention is to provide a solution for cleaning particulate filters which ensures that it can be done in a simple and careful manner. The above objects are achieved with the invention defined by the independent claims.

According to a first aspect, the invention relates to a device for cleaning a particle filter in a muffler for an internal combustion engine. This may, for example, apply to an internal combustion engine arranged in a vehicle, an engine for industrial use or an engine for marine use. The device comprises a disc unit adapted to be arranged in connection with a mounting opening for the particle filter in the muffler to screen off an outlet end of the particle filter. The disc unit has an opening intended to let in air to clean the filter by flowing in one direction, backwards, opposite to a normal flow direction in use.

The device is intended to be used in combination with a suction system, which is arranged to suck air backwards through the opening, i.e. through a limited part of the particle filter, so that cleaning is only performed for a limited part of the filter at a time. In this way, the risk of all the ash stuck in the particle filter being released at the same time reduces and thereby risks damaging other equipment in the muffler such as a catalyst or the like.

The device aims that neither the muffler nor the particle filter need to be disassembled for cleaning the particle filter, but the particle filter can remain mounted in the muffler during cleaning. This saves time and work with unnecessary disassembly of the particle filter for cleaning or replacement. This results in reduced service costs when unnecessary disassembly of the particle filter is saved, lower costs when no filter is replaced, not even with a replacement filter, and simpler logistics compared to a replacement system.

The device is also easy to assemble and disassemble, even with limited access to the particle filter as it is compact, and easy to use.

According to an embodiment of the invention, the disc unit at the opening has an edge side which comprises at least one pressure medium means, such as a compressed air nozzle adapted to discharge cleaning agent, such as compressed air along the edge side, where the pressure medium means is adapted to be connected to a cleaning agent conduit. 10 15 20 25 30 537 008 In this way, the particle filter is cleaned, by pressurized air being forced backwards through the particle filter and transporting away loose particles, such as ash stuck in the particle filter. Likewise, the pressurized air causes even hard-sitting particles in the filter to come loose.

According to a second aspect, the invention relates to a cleaning system for a particle filter in a muffler at a vehicle. The cleaning system comprises a device for cleaning particle filters according to the invention, as well as a suction system.

In addition to the advantages stated above for the device, the cleaning system also has the advantage that the existing exhaust system can be used.

Further features and advantages characterizing the invention will become apparent from the following description with reference to the accompanying drawings, exemplifying an advantageous embodiment of the invention.

Brief description of the drawings Fig. 1 schematically shows a perspective view of a muffler with an exposed particle filter before mounting a device according to the invention, Fig. 2 shows a front view of an embodiment of a device for cleaning a particle filter in a muffler, Fig. 3 shows a cross-sectional side view of the device in Figure 2 and Fig. 4 schematically shows a cleaning system comprising a device according to the invention mounted on a muffler, mounted on a vehicle, which system also comprises a suction system connected to an inlet of muffler.

Detailed description of embodiments of the invention Figure 1 schematically shows a perspective view of a muffler 3 for an internal combustion engine.

The muffler 3 is arranged at a chassis of a heavier motor vehicle and is intended to be part of an exhaust line from the internal combustion engine. The muffler can alternatively be included in many other contexts where a muffler for an internal combustion engine is used, for example in industry and for marine use. However, the figure shows a muffler typically designed for a vehicle, such as a heavier vehicle such as a truck or a bus.

The muffler is essentially square where each side amounts to about 700 mm.

A particulate filter 2, such as a diesel particulate filter (DPF), is arranged in the muffler 3.

The muffler 3 is shown schematically with an exposed particle filter 2 with an outlet end 6 and a mounting opening 5 for connecting a device for cleaning the particle filter 2. When the muffler 3 is in operation, the outlet end of the particle filter 2 is completely covered by a cover (not shown in the figure) . This cover hatch can be mounted with fastening means such as screws, or some quick-release bracket for quick assembly / disassembly. The particle filter 2 is shown only schematically mounted in the mounting opening 5 and some parts are shown only in principle.

In particular in an exhaust line from a diesel engine, additional exhaust after-treatment equipment may be provided in the muffler 2, for example a diesel oxidation catalyst (DOC), arranged upstream of the particulate filter 2, and / or a selective catalytic reduction catalyst (SCR catalyst) of nitrogen oxides, 2. Here a flow direction is defined as the direction that exhaust gases normally take through the muffler 2 during operation of the internal combustion engine.

The muffler is shown exposed but is suitably mounted at or only partially disassembled, eg pulled out in a service position, from its normal place of use, at the vehicle chassis. However, the muffler is disassembled from the exhaust line on an upstream side of the muffler, ie. on an inlet side (hidden in this figure). Fasteners on the muffler for attaching the muffler to the vehicle chassis are shown only schematically.

Figure 2 shows a front view, and figure 3 a side view in cross section, of an embodiment of a device 1 for cleaning a particle filter arranged in its normal place of use at a muffler such as for example the muffler 2 shown in figure 1. Figure 2 also schematically shows a visible part of the outlet end 6 of the particle filter on 10 15 20 25 30 537 008, which device 1 is arranged for cleaning the particle filter 2. The particle filter 2 is here exposed for cleaning, in accordance with what is described above in connection with figure 1.

The device 1 comprises a disc 4, in this embodiment substantially circular, which is adapted to be arranged in connection with the mounting opening 5 for shielding the outlet end 6 of the particle filter. Schematically visible channels in the particle filter 2 are shown as a grid with solid lines. The disc 4 has an opening 7 intended to let in air through the channels which open towards the opening 7, while the rest of the disc 4 covers the other channels of the particle filter and substantially prevents the flow of air. Aperture 7 is thus intended to let in air through only a limited part of the particle filter 2. The disc 4 is adapted, suitably designed so that it fits in the mounting opening 5 in size with suitable play to the mounting opening 5 for easy mounting / disassembly and fastening, with the disc 4 rotatable in the mounting opening 5, but still with a surface covering the outlet end 6 of the filter in a suitable manner over the entire exposed filter surface (corresponding to the outlet end 6) and sealing against it in a suitable manner.

The device 1 is designed as a substantially circular, rotatable disc, in the mounting opening 5 where the aperture 7 is sector-shaped with an arcuate outer surface along the distance indicated by D in the figure. the surface facing and covering the outlet end 6. The gasket is then suitably arranged in an outer edge area of the disc 4 so that the gasket does not block any filter channel but still seals. The board is made of suitable material such as steel, or aluminum and with suitable dimensions, eg about 200 mm in diameter and a thickness between 2-10 mm.

As can be seen from the embodiment shown in Figures 2 and 3, the opening 7 has a radially directed edge side 8 which comprises at least one pressure medium means 9, adapted to discharge over pressure, suitably compressed air or other pressurized gas, along the edge side 8 and adapted to be connected to a line 9a for pressure medium, suitably compressed air or other pressurized gas. In order to be able to use a source of compressed air with limited pressure, valves 9b can be arranged between the line 9a and the pressure means means 9. The pressure means means 9 are adapted to blow through the particle filter 4 with compressed air so that particles stuck in the filter channels are released by the pressurized air. and then backwards can be sucked through the particle filter 2 by a suction plant arranged at the opposite end of the particle filter 2.

In the embodiment shown in figure 2, compressed means 9 are designed as a number of compressed air nozzles, arranged along and opening on a lower side of the disc 4, near the edge side 8. This edge side is here a straight radially directed side of the sector-shaped opening 7. The compressed air nozzles are on the other hand, arranged slightly offset relative to each other in order to overlap each other's working area during a rotation of the disc 4 in the mounting opening 5 in order to ensure that the entire end surface of the outlet end 6 is exposed to compressed air as the disc 4 is rotated. It is suitable that one of the compressed air nozzles 9 is arranged with an orifice around a center area R of the disc 4 in order to ensure that the entire outlet end 6 of the filter can be exposed to compressed air.

For this purpose, the nozzle 9 which is arranged around a center of rotation R of the disc 4 is designed slightly larger than the others which have substantially the same size.

The compressed air nozzles 9 may be in the form of narrow slits extending along the edge side 8.

The device 1 for cleaning the particulate filter 2 also comprises said suction plant which is arranged to suck air through the channels of the particulate filter in a direction which is opposite to the direction which the exhaust gases have during operation of the internal combustion engine. The suction system is arranged at the opposite side of the particle filter 2 than the side at which the above disc 4 is arranged. The suction system is connected so that the entire end surface of the particle filter is exposed to the negative pressure of the suction system. In practice, it is usually possible to achieve this by connecting the inlet of the muffler to the suction system, suitably by loosening a joint of the exhaust line and connecting the inlet of the muffler to the suction system.

Although the entire particle filter is exposed to the negative pressure of the suction system, cleaning is performed by sucking air backwards only through a limited part of the filter. This depends on only the channels opening at the opening 7 allowing passage through the channels, while the inlets to the other channels are covered by the disc 4.

To regulate the flow of cleaning air through the particle filter 2, the disc 4 is provided with a sector-shaped drawbar 10 which is rotatably arranged (shown by bidirectional arrow 15) so that it completely, partially or not at all covers the opening 7. Thus, the size of the cleaning surface (which essentially corresponds to the surface of the opening 7) is checked. This reduces the risk of all ash coming loose at the same time and also gives a higher speed in the gas flow that transports the ash away. The pull hatch 10 is suitably slightly larger to the surface than the surface of the opening 7 in order to be able to completely close the opening 7. The pull hatch 10 can be made of the same material and thickness as the disc 4 in general, but is suitably made of thinner material, e.g. thinner sheet for better handling. It can be pivotally arranged parallel to the disc 4 with a suitable fastening element, e.g. pivotally attached to a narrower portion of the sector-shaped shutter 10.

The disc 4 comprises fastening means 11 intended to rotatably fasten the disc 4 to the mounting opening. By designing the disc with a key grip at its center, for example, the disc 4 can be easily rotated by a mechanic by means of a suitable hand tool so that the opening 7 is caused to assume different rotational positions, after which different parts of the particle filter channels can be exposed for cleaning.

The fastening means 11 can for instance be fastened via bearing means 12a, such as ball bearings, to the center 12.

These fastening means 11 are suitably adapted to existing fastening elements, eg recesses, for fastening the cover (which is not shown) which is mounted over the filter 2 in the finished position of use, i.e. when the filter 2 is not exposed for service such as cleaning. The fastening means 11 may alternatively comprise fastening elements including screws or the like.

According to an alternative embodiment, the device also comprises a center shaft 12 around which the disc 4 is rotatably arranged with a bearing member 13. The center shaft 12 then comprises one or more lines for means for cleaning agents, typically compressed air nozzles.

The center shaft 12 is then suitably provided with a suitable connecting means for connecting to a compressed air source to the disc 4 which in turn contains channels for the various nozzles.

These channels can suitably be designed as drilled channels or closed grooves in the disc 4.

With the above-described embodiment, certain filter channels in the sector corresponding to the opening 7 of the particle filter are purified only by negative pressure from the suction plant, and also by other, significantly fewer filter channels, both by negative pressure and by the overpressure produced by the pressure medium means 9. This provides a highly efficient and careful cleaning of the particle filter 2 in place in the muffler device 3 without the need to disassemble the particle filter 2.

Due to the compact design and a low handling weight, typically between 0.5 - 2 kg, the device also allows a good ergonomic position for the person or persons who are to perform cleaning of the particle filter on site in mufflers, or mount / dismount it.

By arranging the device 1 in different positions during use so that the opening 7, when rotating in the mounting opening 5, is moved over the entire outlet end 6 of the filter, i.e. over its entire end surface, the entire particle filter is carefully cleaned without, for example, large soot particles or other particles coming loose in an uncontrolled manner during cleaning. This solves, or at least limits, the problem that other sensitive equipment for exhaust aftertreatment risks being damaged even though it remains mounted when cleaning adjacent particulate filters. Problems with soot or dust being spread in an undesirable manner in the service room when cleaning is also avoided, which increases the comfort for service personnel.

In alternative embodiments, instead of nozzles for clean compressed air or nozzles for a suitable washing liquid mixed in the compressed air, different combinations of compressed air nozzles and nozzles for a washing liquid or different washing liquids can be used. If different nozzles for different washing liquids are provided, the number of lines 9a is adapted accordingly.

A common line 9a with one or more valves for feeding different washing liquids can also be arranged according to further alternative embodiments. Suitably, the line 9 then runs in a central part, for example a hollow center shaft 12, of the disc 4 and is in use connected to, for example, a source of compressed air (which is not shown in this figure). Figure 4 schematically shows the more detailed design of a cleaning system 20 comprising a device 1 for cleaning a particle filter as described above and the suction system 21 included in the device.

The suction system 21 of the cleaning system 20 is connected to an inlet 3a of the muffler 3. The suction system can be of any suitable type, for example an existing exhaust suction 24 with a dust or particle separator 25 connected thereto, such as a cyclone, a genuine 23 and possibly a filter 22 The dust collector 25 is suitably connected between the inlet 3a and the suction system 21 and acts as a collecting device for the particles which have been cleaned from the particle filter. Since typically an inlet 3a of a muffler in a truck has a diameter of about 110 mm, other suction systems can also be easily connected to the inlet 3a with standardized pipes and connections. The suction system 21 connected to the muffler inlet 3a sucks backwards through the particle filter and transports away loose particles, as well as particles which have been released by the pressure medium discharged through the pressure medium nozzles 9. The fan 23 is suitable for regulating the air flow through the particle filter.

Figure 4 shows the muffler 3 only schematically and in the retracted position at the vehicle's chassis, but depending on e.g. a vehicle type and location of surrounding equipment, the muffler can also be partially extended, for example in a service position, from the vehicle chassis. The inlet 3a is shown in this embodiment disassembled from the exhaust line. When the muffler is to be pulled out, unscrew the fastening device arranged in slide rails and support rails. Then the muffler 3 can be pulled out. The muffler is then not completely outside the vehicle chassis, as it is not necessary to perform service operations. Since the weight of the muffler is between 100 and 150 kg, it is desirable not to have to handle it unnecessarily.

The compact design of the device solves the problem of limited access to the particle filter without having to remove the filter from the muffler. This allows other peripherals, such as other exhaust aftertreatment equipment, such as the urea tank for SCR, to be mounted during the purification of the particulate filter. The device is particularly suitable for a muffler in a truck, but also in a bus, as it can be attached to the side of the rear end of the bus and thus is often difficult to access.

Because the device is so easy to use and has easy access, particle filters can be cleaned at a much lower cost than has been possible so far. Alternatively, cleaning can be performed much more often, which leads to reduced emissions, since the particulate filter is significantly cleaner during a longer operating time than has been possible so far. Thus, the ash contribution in the back pressure can be reduced even before an alarm is given that the filter needs to be cleaned. Although the filter can only be cleaned up to, for example, a 95% degree of purification, this allows the back pressure to be kept low for a much longer time by cleaning the filter more often than is now possible with conventional methods. This reduces the fuel consumption of the internal combustion engine. 11

Claims (8)

537 008 Patent claims Device (1) for cleaning a particle filter (2) arranged in a muffler (3) for an internal combustion engine, the device (1) comprising a disc unit (4) adapted to be arranged in connection with a mounting opening (5). ) for the particle filter (2) in the muffler (3) for shielding an outlet end (6) of the particle filter (2), the disc unit (4) having an opening (7) intended to let in air through only a limited part of the particle filter ( 2), characterized in that the disc unit (4) at the opening (7) has an edge side (8) at which edge side (8) at least one pressure means means (9) adapted to lead pressure means out towards the outlet end (6) of the particle filter (2) is arranged , where the means (9) is adapted to be connected to a conduit (9a) for pressure means. 2.. Device according to claim 1, characterized in that the disc unit (4) is substantially circular and the opening (7) is sector-shaped. 3.. Device according to one of the preceding claims, characterized in that the disc unit (4) comprises an adjustable drawbar (10) adapted to cover the opening (7). 4.. Device according to one of the preceding claims, characterized in that the disc unit (4) comprises fastening means (11) intended to rotatably fasten the disc unit (4) to the mounting opening (5). 5.. Device according to claim 1, characterized in that the disc unit (4) comprises a center axis (12) around which a bearing member (13) is arranged and in turn is arranged at the fixed member (11) for rotatably arranging the disc (4) in the mounting opening (5). ). 6.. Cleaning system (20) for a particle filter (2) arranged in a muffler (3) for a dry combustion engine, which comprises a device (1) for cleaning a particle filter (2), according to any one of the preceding claims and a suction system (21) connected to an inlet (3a) of the muffler 3 for producing a vacuum produced by the vacuum through the particle filter (2). 12 5 537 008 Cleaning system according to claim 6, characterized in that the suction system (21) comprises a fl genuine (23) adapted to regulate the air genom through the particle 2 filter (2). Cleaning system according to claim 6 or 7, characterized in that the suction system (21) comprises a collecting device for (25) the particles cleaned from the particle filter (2). 13