Soot filter for diesel vehicles.

p0001The invention relates to a soot filter for diesel engines with a cylinder disposed in a housing with preferably conical Abgaszu- and outlet nozzles filter body having a plurality of mutually parallel channels which are separated by thin filter walls, wherein one half of the channels (raw gas) for Abgaszuführstutzen and other half (clean gas ducts) have been completed and open toward the other side to Abgasabführstutzen.

p0002Such soot filters, which are already known in many different embodiments, all show the fundamental difficulty that clog the walls of the filter body with the time by the deposited soot and so that such a high back pressure builds up that the filter does not fulfill its effectiveness can. For this reason, such a soot filter must always be removed at intervals back of the deposited soot particles, which is usually achieved in addition to a chemical cleaning of the filter surface in practice in such a way that the filter cartridges are burned.

p0003Because of this burn-off can not generally be performed simultaneously during the operation of the soot filter, but only at a standstill of the engine, and the burning in addition, because of the danger of overheating of the commonly made of ceramic material soot filter, the risk of breakage, and thus a destruction of the entire filter implies there is a need for an improved and simpler gentler filter cleaning. Moreover, there is the difficulty that even with the combustion of the soot, the problems obstructed filtering surface and higher backpressure are not eliminated because the remaining Verunreingiungsteilchen (ashes) remain in the filter as before, and thus the gas passage of the exhaust gas from the Rohgaskanälen hinder the clean gas ducts.

p0004The invention is therefore based on the object, a soot filter of the type mentioned in such a way that a simpler, gentler and more effective cleaning of the filter body is possible.

p0005To achieve this object the invention provides that the crude gas flow into a Rußkammer which is provided with a closable soot outlet.

p0006While in conventional particulate filters of the generic type, the raw gas were simply closed at the end of the filter, ie the raw gas were formed as blind holes (like the rest of the clean gas ducts, in which, however, the opening at the outlet end and not the exhaust gas inlet side is arranged), is at the soot filter according to the invention the closure is not directly provided at the end of the filter body, but behind all the raw gas, a so-called. Rußkammer is connected, which can be closed in turn, so that their action the conditions when working of such a particulate filter are the same. The raw gas enters the raw gas and the walls must enforce the clean gas ducts, since it can not leak even through the closed operating Rußkammer. When passing through the filter walls the soot settles on the inner walls of the raw gas. The thus freed of soot and other solid contaminants exhaust gas passes through the clean gas ducts in the downstream of the filter exhaust pipe and is discharged there. However, the provision of the Rußkammer according to the invention has the advantage that for cleaning the crude gas if necessary, it only requires an opening of the carbon black-outlet opening of the Rußkammer, so that in the channels sitting on the walls of soot particles are entrained and discharged through the exhaust gas. This course is also a discharge of soot particles, which have passed through the shock and the gas flow from the outset in the Rußkammer and already had a reduced clogging of the filter surfaces of the filter body to follow through their arrangement in this Rußkammer and thus a longer service life of the soot filter to have a result. Shelter time is understood to be the time that works just with sufficient effectiveness before is too high by the addition of the filter surfaces with carbon black, the back pressure.

p0007The formation of a Rußkammer invention can be achieved in development of the invention very advantageous in the way that a, together with the filter body, an intermediate chamber in the housing at a distance behind the filter body forming transverse wall provided and that the clean gas or crude gas penetrating through the intermediate chamber pieces of pipe with the end chamber are connected behind the bulkhead.

p0008The training can either be taken so that the clean gas ducts open into the connected to the exhaust pipe end chamber and the intermediate chamber forms the Rußkammer, or else that the raw gas through the pipe sections in which open the Rußkammer forming end chamber and the intermediate chamber with a , preferably lateral, clean gas outlet is provided. If necessary, could also be formed in a conventional manner coaxially to the cylindrical housing generally and in this case, coaxially within the outlet conduit of the Rußkammer in the latter embodiment of the clean gas outlet to the intermediate chamber. To this end, however, the pieces of pipe connecting the raw gas with the end chamber would then be bundled to the end chamber conically outwards in the middle to make room for the Reingasauslaßleitung what it prepares structural difficulties in practice, especially when there are multiple channels, thus also many pieces of pipe are provided.

p0009The formation of a soot filter according to the invention may be made in the simplest case so that behind the soot-outlet a Rußsack od. Like. Can be connected, so when blowing the raw gas of soot accumulates in such a, like a vacuum cleaner filter formed Rußsack which clears are can.

p0010In addition, however, the settling in the Rohgaskanälen soot course be burned in a known manner, the present invention given possibility of direct Threading through the raw gas, which was not even given in the sack channels known to date, a significant improvement of burn entails and in particular the possibility that any ash and other contaminant particles are also to be held and not remain within the channels.

p0011For discharging of the carbon black by opening the Rußkammer can be provided finally even that can be switched in a bypass line between the outlet port and a downstream soot point in Reingasauslaßrohr a second soot filter is switched with Rußabbrennvorrichtung. To clean the switched in the engine exhaust passage main soot filter the Rußauslaßöffnung the Rußkammer is opened and brought by the engine exhaust of carbon black into the second particulate filter, where it is deposited. Then - what yes only takes a very short period of time to complete - sealed the soot discharge line again, so that the motor can readily continue to operate. The burning is not done actual main particulate filter itself, but in the second soot filter, the soot had been blown before.

p0012In practice, one is usually provided the soot filter with a Abbrennvorrichtung, such a soot filter with Rußabbrennvorrichtung that arranged in the region of Abgaszuführstutzens air and fuel supply and an ignition device includes, according to another feature of the present invention is characterized in that the Abgaszuführstutzen double is formed as a fuel and / or air mixing and distribution chamber, wherein the inner wall is provided with a plurality of distributed around the burner openings.

p0013While the fuel supply line, preferably a gas line, only the outer wall of the double Abgaszuführstutzens passes through, in order to achieve that the fuel only is distributed in the mixing and distribution chamber formed by the double walls and thus a uniform burning over the entire inner surface and hence also a more uniform can take place burning of their opposing filter body, the air supply lines the distribution enforce preferably completely, where they are provided with one-way or Pulsairventilen so that they close during the commissioning of the engine through the exhaust gas pressure, while with the engine off with the torch is they can be opened to supply air. Optionally, however, may also have an additional compressed air line may be provided in order to achieve a gain through the flow through the filter during the burning of the filter.

p0014Such flow increase and thus an improved burning off the soot in the filter body finally can also be achieved in that downstream a fan for the suctioning of the exhaust gas is disposed on the filter body in a further embodiment of the invention. This blower may comprise either a side connected to the exhaust pipe suction blower, in which case the end of the exhaust pipe a pivotable closure flap must be applied so that when switching on of the aspirator, the valve closes and no air for the exhaust end can be sucked. Alternatively, however, could also be a downstream inclined einmündendes into the exhaust pipe pressure blower can be provided, since a static negative pressure is created by such a pressure fan which causes a strong air flow through the end of the exhaust pipe, reverse at the junction point of the turn to the increased intake of the combustion gases during the burning of the soot in the filter body ensures thereby an improved cleaner burning and especially a gentler burning is achieved by maintaining lower temperatures on the filter body. These actions of the special training of Rußabbrennvorrichtung through the double-walled construction of Abgaszuführstutzens and achieving a better burn-through the through eyes of the combustion gases by means of a suction or specially arranged pressure blower can be used very advantageously evident even in conventionally designed soot filters. can but is preferred in any case, the provision of a common Rußkammer for the outlet ends of the raw gas, as this purification is much easier and, above all, during the burning of a much gentler uniform burning take place, as it is possible within closed-channels is where the danger of localized heat overloads and thus a crushing and a destruction of the filter body would be given.

p0015Further advantages, features and details of the invention will become apparent from the following description of some training examples and from the drawing. They show:<ul><li>FIG. 1 shows a schematic section through an inventive particulate filter with an opening into Rußkammer Rohgaskanälen,</li><li>Fig. 2 is an enlarged view of the region II in Fig. 1,</li><li>Fig. 3 shows a schematic cross section along the line III-III in Fig. 1,</li><li>Fig. 4 a of Fig. 1 corresponding section through a modified embodiment in which the Rußkammer forms the end chamber of the filter housing,</li><li>Fig. 5 is an enlarged illustration of the detail V in FIG. 4,</li><li>Fig. 6 a Längsschnbitt, through a soot filter with Rußkammer and additional means for equalizing both the soot deposition and the Rußabbrandes</li><li>Fig. 7 is an end view of the arrangement according to FIG. 6, from left, not all of which opens connection cables and components are marked with</li><li>Fig. 8 is a section along the angled line VIII-VIII in Fig. 7, and</li><li>Fig. 9 is a schematic representation of a double soot filter, in which in the bypass circuit to the main Rußkammer of the soot filter, a second soot filter is connected.</li></ul>

p0016In the metallic housing 1 having conical Abgaszuführstutzen Abgasabführstutzen 2 and 3 a filter body 4 is made of metal or ceramics, containing a plurality of mutually parallel channels. These form one half raw gas 5, which are open and closed towards the other side to Abgaszuführstutzen 2 and the other half clean gas ducts 6, which are closed for Abgaszuführstutzen out, but for Abgasabführstutzen 3 open towards. The incoming raw gas in the 5 gas passes through the thin filter walls to the adjacent clean gas passages, whereby the soot deposited on the channel walls.

p0017According to the raw gas are now not simply terminated at the end, as these are the clean gas ducts at the other front end, but they open all into a Rußkammer 7, which in turn is also openable lockable by a schematically illustrated as a disc-lock device 8 and when required. In operation, the locking device 8 is so set that the Rußkammer 7 is closed, whereby the same effect is achieved in the end, as if each of the raw gas would be individually closed at the end. In the end, the raw gas through the thin filter walls 10 in the clean gas ducts must, which separates the soot. However Rußkammer invention with verschließbaen Rußauslaßöffnung 11 offers the possibility for a clogging of the raw gas to blow out this on Rußkammer by the shutter 8 is opened so that the exhaust gas stream is the easier way and that means he does not passes through the filter walls 10 but flows through at high speed, the raw gas and thereby entraining the present in these soot particles with and transmits it via the soot exhaust port 11, the further disposal will be further described in detail below. The provision of the mentioned Rußkammer 7 requires pieces of pipe 12 for connecting the clean gas ducts 6 with the discharge pipe 3. This provided on both sides with tapered sections pipe pieces 12 on the one hand inserted into the clean gas ducts and on the other in coaxial with them arranged bores of the transverse wall 13, which together with the compute-th front edge of the filter body 4 which Rußkammer 7 in the housing 1 is limited.

p0018In addition to the simple discharge of soot by blowing at an opening of the soot-outlet (11) the Rußkammer 7 invention also has significant beneficial importance during burnout of the filter body to which is not completely get around even with such a mechanical additional cleaning action. At times, the soot particles set so firmly to the wall, that they can not be easily released by blowing, but must be burned. In accordance with the invention so, then both sides open Rohgaskanälen during burning can be done a lot faster flowing, so that on the one hand, a discharge also all ash particles with can be done and can be secured to the other, that the walls of the filter body does not get so hot that they destroyed will.

p0019In contrast to the embodiment according to Figures 1 to 3 Figures 4 and 5 show a modified embodiment in which not disposed between the filter body 4 and the transverse wall of the intermediate chamber forms the Rußkammer, but the end chamber 14 forms the Rußkammer, while the intermediate chamber 7, the common collecting chamber for the clean gas channels so that the clean gas outlet port 15, which was located in FIG. 1 coaxially with the raw gas inlet port, as now laterally arranged outlet opening 15 'in Fig. 4 appears. To this end, not the clean gas pipes are in the embodiment of Figures 4 and 5 are connected through the attached pipe sections 12 with the fluid chamber 14, but instead the raw gas 5. The clean gas ducts 6 on the other hand open freely into the intermediate chamber. 7

p0020Fig. 6 shows an extended structure in which before the soot-filter body 4 is preferably designed as a honeycomb catalyst gas diffusor 16 is arranged in addition to providing in this case, the intermediate chamber 7 forming Rußkammer with a lateral soot outlet port 11 still. This is a more even distribution of the exhaust gases and thus a more uniform loading of the soot filter body 4. It also serves the uniform distribution and a better and more uniform combustion of soot on the filter surfaces.

p0021Moreover, it is provided in this embodiment that the Abgaszuführstutzen 2 is double-walled with an outer cone 17 and an inner cone 18th The fuel supply through the fuel supply line 19 occurs in the space between the two conical lateral surfaces 17 and 18 so that this space (see FIG. In particular FIG. 8), a mixing and distribution chamber 20 forms, via a plurality of burner openings 21 over the entire circumference of the inner cone 18 are distributed, a uniform all around arranged flame distribution and thus bring about a uniform combustion. Although the air may be introduced into this distribution chamber 20 in special cases, is provided by way of derogation in the illustrated embodiment, the air supply lines 22 through contact with applied pulse-air valves 23 to double Abgaszuführstutzen entirely. The pulse-air valves are used to effect an independent complete the air supply openings in the normal engine operation (one-way valves). however, the motor is turned off and to the soot filter to be burned, so open when supplying the fuel and the ignition of the mixture by means of a schematically indicated internal electrode 24 through the train of the fuel gas by the soot filter through the pulse-air valves 23 so that the necessary combustion air is available.

p0022At 25, a temperature sensor is schematically illustrated, which detects the temperature of combustion, which may also serve to control the fuel supply, in particular gas supply, and optionally, to introduce more or less compressed air into the combustion chamber before the abzubrennenden filter.

p0023To support the combustion gas stream during burnout of the filter body 4 through the filter body therethrough, a suction fan 26 may be provided which is laterally flanged to the exhaust pipe 27, wherein a pivotally at the exhaust end hinged flap 28 in Abbrennfall closes the exhaust pipe, so that no false air is drawn from the rear can be, but the aspiration actually takes place through the filter body 4 therethrough. During normal engine operation, the fan 26 is turned off and thus the off let 29 blocked, so that the exhaust gases under up-swinging of the flap 28 can normally exit via the exhaust. Instead of a suction fan possibly could. Also, as indicated in Fig. 6 in dashed lines, a vacuum blower 26 uses', opens on a downstream inclined pipe 30 into the exhaust pipe 27 and forms due to the flow rate a vacuum in the junction area in the exhaust pipe 27 which, the similarly provide for a better by sucking through the filter body, such as a suction fan 26. in using such a pressure blower with a particular inclination of the injection pipe 30 in the rest of a pivotally hinged flap 28 would not be required. The Fig. 9 finally shows a tandem circuit in which the Rußablaß 11 of the exhaust passage in the engine lying main soot filter F1, a second soot filter F2 is connected, which is applied via a change valve arrangement V2 back to the exhaust pipe 27 in the bypass circuit. With closed valve V1 which the closure device 8 in this case forms in Fig. 1, the device operates as shown in FIG. 9 as the soot filter devices in Figures 1 to 8, wherein, if necessary, of course, the fan may be provided. However, the reasons of clarity, in Fig. 9 have been omitted. To clean the main soot filter F1, the valve V1 is opened, wherein the carbon black is not simply discharged, for example, in a Rußbeutel or the like., But passes into the second particulate filter F2. Then the valve V1 is closed again, so that the main soot filter in the exhaust stream of the engine again operate normally, and therefore can continue to run and the motor, while now, however, the carbon black is burned without affecting the motor function in the second soot filter F2 by means of an only schematically indicated Abbrennvorrichtung 32 , the air supply and fuel supply, igniter may comprise etc. Instead of deriving the soot from the main soot filter F1 via the second soot filter F2 and the resulting possibility of Abbrennes the soot during the journey, the soot filter F1 can naturally be cleaned by vacuuming, which has been already mentioned several times.

p0024The invention is not limited to the illustrated embodiment. Besides the possibility of providing other Abbrennvorrichtungen (which yes a Abbrennvorrichtung at providing a Rußkammer is not necessarily required), as well as the possibility of using other configurations of soot filter bodies 4 about, for example, in practice, appropriate and feasible, instead of separate pipe pieces to provide 12 that these connectors 12, which pass through the intermediate chamber 7, the filter body 4 are directly connected integrally formed, which is particularly easy if it is made as a compact of ceramic material.