SE1350006A1 - Arrangement for filtering soot particles from an exhaust gas flow of an internal combustion engine - Google Patents

Abstract

SUMMARY The invention relates to an arrangement (100) for filtering soot particles from an exhaust stream of an internal combustion engine (2). The arrangement comprises an exhaust gas collector (20), which collects exhaust gases from the cylinders (2a-2f) of the internal combustion engine, each of the cylinders (2a-2f) being connected to the exhaust gas collector (20) via an outlet duct (22a-22f). A filter device (24; 24 '; 24a-24f) is arranged in each of the outlet ducts (22a-22f) between the cylinders (2a-2f) of the internal combustion engine and the collecting chamber (21) of the exhaust gas collector (20), each of the filter devices ( 24; 24 '; 24a-24f) comprises a fiber filter (240; 240') of silica fibers and is adapted to filter particles from the exhaust floc by the particles getting stuck on or trapped by the fibers of the fiber filter. The invention also relates to a filter device (24; 24 '; 24a-24f) for the arrangement (100) and an exhaust system which comprises the arrangement and / or the filter device and a vehicle which comprises the exhaust system. Through the arrangement, fouling of equipment downstream can be reduced if an internal combustion engine with respect to the flow direction of the exhaust gases is reduced and also the total emission to the atmosphere can be reduced.

Description

FIELD OF THE INVENTION The invention relates to an arrangement for filtering soot particles in an exhaust stream of an internal combustion engine and a filter device for the arrangement. The invention also relates to an exhaust system comprising the arrangement and / or the filter device and a vehicle comprising the exhaust system.

BACKGROUND OF THE INVENTION Internal combustion engines are used in several types of applications and vehicles today, for example in heavy vehicles, such as trucks or buses, cars, motor boats, ships, ferries or ships. Internal combustion engines are also used in industrial engines and / or motor-driven industrial robots, power plants, season e.g. electric power plants that include a diesel generator, and in locomotives.

Exhaust gases from internal combustion engines, especially Than diesel engines, include combustion residues, such as soot particles. Diesel-powered motor vehicles are therefore equipped with exhaust gas purification devices in order to reduce emissions of particles and chemicals that occur in the diesel engine's exhaust gases. To regulate emissions from Iranian vehicles, there are various standards and legal requirements that regulate levels of permissible exhaust emissions.

There is a great need to reduce the number of particles in the exhaust gases. In addition to the fact that the legal requirements must be met, there is also a need to protect various pipes, ducts and devices in the vehicle's exhaust system downstream of the combustion engine. If the exhaust stream contains large amounts of particles, the particulate filter in the exhaust system is also contaminated. This meant that particulate filters almost regenerated frequently. Regeneration can be made into an example by burning the soot particles at high temperatures. If the temperature during engine operation does not become sufficiently high, engine guards are required to raise the temperature. This in turn leads to higher fuel consumption.

Several different methods and devices have been proposed for exhaust gas purification. For example, in a published patent application US2002 / 0189247, it is proposed to use two-stage filtration downstream of an internal combustion engine. In a first step, a filter device is used in the engine exhaust collector.

The filter device comprises a nonwoven filter material of metal fibers. The filter device is substantially circular-cylindrical and comprises a plurality of axially extending channels which are arranged radially over the internal volume of the cylinder. The nonwoven material is placed in the channels of the filter device. The disadvantage of this solution is that the structure of the filter device is rigid and that it cannot be adapted to different types and sizes of wires and channels in a simple way.

There is therefore still a need for a simple and space-saving solution to reduce the number of particles in the exhaust stream.

SUMMARY OF THE INVENTION The object of the present invention is to reduce fouling of equipment downstream of an internal combustion engine with respect to the flow direction of the exhaust gases. In particular, it is an object to reduce the number of particles in the exhaust stream in order to reduce the need for cleaning and / or regeneration of cleaning devices downstream of the combustion engine in the exhaust system.

It is a further object of the invention to clean the exhaust stream without significantly affecting engine performance. It is a further object of the invention to provide a filter device which can be adapted to narrow outlets.

These objects are achieved with an arrangement as defined in claim 1 and a filter device for the arrangement as defined in claim 8.

According to a first aspect, the invention relates to an arrangement for filtering soot particles Than an exhaust stream of an internal combustion engine. The arrangement comprises an exhaust collector which collects exhaust gases from the cylinders of the internal combustion engine, each of the cylinders being connected to the collection chamber of the exhaust collector via an outlet duct. A filter device is arranged in each of the outlet ducts between the cylinders of the internal combustion engine and the collection chamber of the exhaust gas collector. Each of the filter devices comprises a fiber filter of silica fibers and is adapted to filter particles from the exhaust stream by the particles getting stuck on or trapped by the fibers of the fiber filter. By means of this arrangement the filter device acts as a pre-filter and soiling of equipment downstream of a combustion engine with respect to the flow direction of the exhaust gases can be reduced. The total emission to the atmosphere can also be reduced with the arrangement according to the invention.

According to another aspect, the invention relates to a filter device for the arrangement. In the manner described above in connection with the arrangement, the filter device comprises a fiber filter of silica fibers, which filter is adapted to filter particles Than the exhaust stream. This is done by the particles getting stuck on or trapped by the fibers of the fiber filter. The fiber filter is mainly fit with an Open first spirit and a closed second spirit. By shaping the filter as a pass, the surface of the filter can be increased in a simple way. The larger the surface area of the filter, the better the degree of filtration can be achieved.

The invention also relates to an exhaust system which comprises the arrangement and / or the filter device above truly a vehicle which comprises the exhaust system. 4 Fiber filters have many advantages. They are flexible and can be easily adapted to tight spaces. Fiber filters are easy to manufacture and can be formed, for example, by compression molding into a desired shape, whereby the adaptation to narrow spaces is further improved. Fiber filters comprise a large number of fibers, a large effective surface being provided for receiving and trapping soot particles, which can be trapped in tangled fibers and / or stick to the surface of the fibers. As a result, a high degree of purification can be achieved.

Additional features, purposes and advantages will be apparent from the following detailed description.

BRIEF DESCRIPTION OF THE ROPES Figure 1 schematically shows a side view of a truck comprising an internal combustion engine with an exhaust gas collector.

Figure 2 schematically shows an arrangement according to an embodiment of the invention.

Figure 3 schematically shows a side view of a filter device according to an embodiment of the invention.

Figure 4 schematically shows a section of an alternative filter device.

DETAILED DESCRIPTION The exhaust gas condenser is a device that includes a truth scanner in which the exhaust gases from the exhaust ducts of the cylinders flow. The exhaust gas collector also includes an exhaust outlet. Each of the cylinders is connected to an outlet duct and the outlet ducts are connected to the collection chamber.

An arrangement according to the invention for reducing the number of particles in the exhaust stream before the exhaust stream leaves the exhaust collector comprises at least one filter device in an outlet duct between the cylinder (s) of the internal combustion engine and the collection chamber of the exhaust collector. The exhaust stream can then be passed on to further exhaust purification in an exhaust system, for example to a particulate filter and / or a catalyst.

The filter device comprises a fiber filter of silica fibers and is adapted to filter particles from the exhaust stream by the particles getting stuck on or trapped by the fiber filter and / or on the fibers of the fiber filter. The fibers in a filter are randomly tangled and form a seam and soot particles, which may have a sticky surface, can thereby both adhere to the surface of the silica fibers and become trapped in the formed fiber net.

Since the filter device according to the invention functions as a pre-filter, a degree of particle filtration of about 60-80% is acceptable, whereby devices, lines and ducts downstream of the engine can be at least partially protected from contamination. The degree of filtration can of course be even higher.

Silica fibers are heat-metal and also resistant to various chemicals. Since the silica fibers speak at high temperatures, the trapped and / or stuck soot particles in the fiber filter can be burned spontaneously or in a controlled manner and the filter can thereby be regenerated. Therefore, they are excellent for use in connection with internal combustion engines.

The silica fibers are preferably of pure silica. An example of fibrous material of this type is supplied by the company Saint Gobain Quartz, for example under a brand name Quartzel® Wool.

The fibers in the fiber filter can also be coated with a catalytic material in order to be able to burn off particles continuously at relatively low temperatures - from about 200 ° C to 250 ° C. The catalytic material may be a noble metal, for example vanadium, rhodium and / or palladium, or some other catalytic material.

The silica fibers are packed to form a fiber filter. By packing is meant that the fibers, which are often delivered as a fiber mat, in which the silica fibers are randomly arranged, are compressed, for example, mechanically to a desired volume and / or shape. The filter can also be formed by compression molding. 6 The fibers are malleable and can take almost any shape and can therefore be adapted to different applications. In addition, the fiber filter can follow hooks in ducts and is therefore usable even in such systems which contain hooks.

In order to obtain such a high degree of filtration as is possible with a fiber filter, the surface of the fiber filter should be maximized. The filter device according to the invention is substantially fit with a 6ppen first spirit and a closed second spirit, whereby a relatively large filtration surface is obtained. For example, in one type of exhaust gas collector, the filter may be substantially circular-cylindrical and form a fit filter. The surface of a filter in the exhaust gas collector can be at least about 0.1 m2. In theory, the surface of the filter has no upper limit, but for practical purposes, the upper limit is about 0.3 m2, depending on the exhaust in the exhaust sensor. To further maximize the surface area that can trap the soot particles, the fibers preferably have a diameter of about 7-10 microns.

The thickness of the filter also affects the degree of filtration of the filter. The rock thickness of the filter depends on the size of the filter, the air flow in the system in question and the degree of purification desired, but can vary between 10-30 mm and is preferably between 15 and 20 mm.

An additional parameter that affects the degree of filtration is the porosity of the fiber filter. The porosity defines how much air the fiber filter contains. The porosity is preferably as high as possible, for example between 95-96%, so that the back pressure in the exhaust system is not affected significantly. If the porosity is Over 96%, there is a risk that the filter will be compressed by the exhaust stream. The fiber filter can have a porosity between 92-96% so that the back pressure in the exhaust system can be kept at an acceptable level. Low pressure in the exhaust system results in better engine performance, reduces fuel consumption and thus the amount of harmful exhaust gases can be reduced.

The exhaust flow in each channel after the respective cylinder of the combustion engine can vary between about 100-500 m3 / h. With larger exhaust floods, the risk of the filter being compressed during operation increases. The open front end of the fit fiber filter preferably has a cross-section corresponding to the cross-section of a channel in which the filter device is intended to be placed. For example, the cross section may be circular. This facilitates mounting of the filter in a duct or conduit in a desired position.

The filter device may comprise at least one flange and the open spirit may be provided with the flange or the like. The flange has a shape and size corresponding to the shape and size of the channel in which the filter device is intended to be placed. The flange can be provided with mounting elements, for example a clamping device, to further facilitate mounting and disassembly of the filter device in a channel.

The fiber filter can be surrounded by a metal mesh. The metal mesh gives stability and stability to the filter. Preferably, the metal mesh is also flexible and can thereby be adapted to tight spaces.

The invention is described below with further reference to Figures 1-4.

Figure 1 shows a vehicle 1 in a schematic side view. The vehicle 1 is provided with an internal combustion engine 2, which drives the drive wheel 4 of the vehicle 1 via a gearbox 6 and a propeller shaft 8. The internal combustion engine 2 is provided with an exhaust system 10 in which a muffler 12 is arranged. The internal combustion engine 2 is driven by a fuel 14, which is fed to the internal combustion engine 2 with a fuel system 16 comprising a fuel tank 18. An arrangement 100 for filtering particles Than the exhaust stream is arranged at the internal combustion engine 2.

Figure 2 shows the arrangement 100 in more detail. The internal combustion engine 2, comprises six cylinders, 2a, 2b, 2c, 2d, 2e and 2f (2a-2f). The number of cylinders can be either higher, for example 8, or lower, for example 4 or 2. Inlet air is fed to the cylinders of the internal combustion engine via a branch 30. Each of the cylinders 2a-2f is connected to an exhaust collector 20. The exhaust collector comprises a truth chamber 21 and outlet ducts 22a, 22b, 22c, 22d, 22e and 22f (22a-22f). Each of the outlet channels 22a, 22b, 22c, 22d, 22e and 22f (22a-22f) is connected to a cylinder 2a, 2b, 2c, 2d, 2e and 2f (2a-8 2f). A filter device (24a-24f) is arranged in each of the outlet ducts (22a-22f) between the cylinders (2a-2f) of the combustion engine and the collecting chamber 21 of the exhaust gas collector 20. / or captured by the filter devices (24-24f). Thereafter, the exhaust gases are discharged from the exhaust gas collector through an exhaust outlet 40 to subsequent devices, which are not shown in detail.

Each of the filter devices 24a-24f may have a similar structure shown schematically, but in more detail, in Figures 3 and 4.

Figure 3 shows a filter device 24 which comprises a fiber filter 240 and a flange 243. The fiber filter 240 and thereby the fiber device 24 is substantially fit and has an open first spirit 241 and a closed second spirit 242. The filter is surrounded by a metal mesh 244 which provides stability to the filter device. The metal mesh is arranged so that the filter device 24 is still flexible and can be adapted to narrow outlets.

Figure 4 shows a section of a filter device 24 '. The filter device 24 'comprises a fit fiber filter 240' with a circular cross section. The fiber filter 240 'and thereafter the filter device 24' have an open first end 241 'and a closed second end 242'. The filter device 24 'also comprises a flange 243' which facilitates mounting of the filter device in a channel.

The filter in this embodiment is not surrounded by a metal mesh.

The filter device with a fiber filter described above is suitable for use as a pre-filter in an exhaust gas collector. In particular, the filter according to the invention can be used in smaller engines, i.e. engines which have a cylinder volume equal to or below 10 dm3.

An example of an arrangement according to the invention is as follows. The arrangement comprises an internal combustion engine with 6 cylinders. Each cylinder has an exhaust flow of 300 m3 / h, which is relevant on smaller engines, ie. on engines that have a cylinder volume below 10 dm3, especially during so-called 9 bus operation. The filter has an outer diameter of about 100 mm and a length of about 500 mm and the outer surface of the fiber filter is about 0.15 nn2. The rock thickness is about 15 mm and the porosity about 95-99%. With such a filter, a filtration degree of about 60-80% can be obtained. With these dimensions, the back pressure in the system becomes acceptable and the performance of the internal combustion engine is not increased.

The above examples and embodiments are not limiting of the invention, but the invention can be varied freely within the scope of the claims.

Claims (16)

PATENT REQUIREMENTS An arrangement (100) for filtering soot particles from an exhaust stream of an internal combustion engine (2), the arrangement comprising an exhaust gas collector (20), which collects exhaust gases from the cylinders (22-2f) of the internal combustion engine, each of the cylinders (2a -2f) is connected to the collection chamber (21) of the exhaust collector (20) via an outlet duct (22a-22f), characterized in that a filter device (24; 24 '; 24a-24f) is arranged in each of the outlet ducts (22a-22f). ) between the cylinders (2a-2f) of the internal combustion engine and the collection chamber (21) of the exhaust gas collector (20), each of the filter devices (24; 24 '; 24a-24f) comprising a fiber filter (240; 240') of silica fibers and adapted to filter particles from the exhaust stream. Arrangement according to claim 1, characterized in that the filter device (24; 24 '; 24a-24f) is substantially fit with an open first spirit (241; 241') and a closed second spirit (242; 242 '). Arrangement according to any one of claims 1 or 2, characterized in that the open first end (241; 241 ') of the filter device (24; 24'; 24a-24f) has a cross section corresponding to the cross section of the respective outlet duct (22a-22f). An arrangement according to any one of claims 1-3, characterized in that the filter device (24; 24 '; 24a-24f) comprises at least one flange (243; 243') to facilitate installation of the filter device (24; 24 '; 24a-24f ) in the respective outlet duct (22a-22f). Arrangement according to any one of claims 1-4, characterized in that the silica fibers have a diameter of about 7-10 μm. Arrangement according to any one of claims 1-5, characterized in that the silica fibers are coated with a catalytic material, such as noble metal. Arrangement according to any one of claims 1-6, characterized in that the fiber filter (240) is surrounded by a metal mesh (244). 11 A filter device (24; 24 '; 24a-24f) for an arrangement (100) according to any one of claims 1-7, characterized in that the filter device (24; 24'; 24a-24f) comprises a fiber filter (240; 240 ') of silica fibers, which filter (240; 240 ') is adapted to filter particles Than the exhaust stream, the fiber filter (240; 240') being substantially fit with an Open first spirit (241; 241 ') and a closed second spirit (242; 242 '). Filter device (24; 24 '; 24a-24f) according to claim 8, characterized in that the silica fibers are coated with catalytic material, such as noble metal. Filter device (24; 24 '; 24a-24f) according to any one of claims 8 or 9, characterized in that the fibers have a diameter of about 7-10 μm. Filter device (24; 24 '; 24a-24f) according to any one of claims 8-10, characterized in that the open first end (241; 241') of the fiber filter (240; 240 ') has a cross-section corresponding to the cross-section of a channel in which the filter device (24; 24 '; 24a-24f) is intended to be placed. Filter device (24; 24 '; 24a-24f) according to any one of claims 9-11, characterized in that the filter device (24; 24'; 24a-24f) comprises at least one flange (243; 243 ') to facilitate mounting of the filter device (24; 24 '; 24a-24f) in a channel in which the filter device (24; 24'; 24a-24f) is intended to be placed. Filter device (24; 24 '; 24a-24f) according to any one of claims 9-12, characterized in that the fiber filter (240; 240') is surrounded by a metal mesh (244). Exhaust system (10), characterized in that it comprises an arrangement (100) according to any one of claims 1-7. Exhaust system (10), characterized in that it comprises a filter device (24; 24 '; 24a-24f) according to any one of claims 8-13. A vehicle (1), characterized in that it comprises an exhaust system according to claim 14 or 15. 1/4 "c" - 2/4 100 24c 24d 24e,) () „,,, N / k,) - --ra 2b 2c 2d 2e 2f T I17— 24a 24b 22d -. - 22e '22f 24f 2 22a, 22b 22c' 21 Figure 2 24 3/4 2 - 241 244 243 Figure 3 414 240 '242' Figure 4