DE3501405A1 - Device for the removal of soot particles from exhaust gases of a diesel engine - Google Patents

Abstract

Device for the removal of soot particles from exhaust gases of a diesel engine with filter arranged in the exhaust pipe, in which the exhaust pipe (2) is divided into at least two branch pipes (3, 4), a filter cartridge (5, 6) is arranged in each branch pipe (3, 4), each branch pipe (3, 4) in the area of both ends of the filter cartridges (5, 6) is respectively provided with a shut-off valve (7, 8, 9, 10), an air line (13, 14, 15, 16) opens into the closable part of each branch pipe (3, 4), at both ends of the filter cartridges (5, 6) in each case, each of which air lines is provided with a shut-off valve (18, 20) and to which air can be admitted in the filter cartridge (5, 6), viewed counter to the direction of flow of the exhaust gases, and in addition, viewed in the direction of flow of the exhaust gases, at least that air line (13, 15) connected upstream of the respective filter cartridge (5, 6) is connected to the combustion-air feed line (12) leading to the diesel engine (1). <IMAGE>

Description

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Description: Device for removing soot particles from the exhaust gases of a diesel engine

Description; ·

The invention relates to a device for removal of soot particles from exhaust gases of a diesel engine with a filter arranged in the exhaust pipe.

When examining the exhaust gases from internal combustion engines, indications have emerged that the in these exhaust gases contained particles, especially soot particles, can be toxic and possibly carcinogenic effects can have. For this reason, efforts are made to filter these particles with the help of mechanical filters, for example Steel wool filters, ceramic filters or the like. From to remove the exhaust gases. These filters allow such particles to be removed almost completely.

However, there is a disadvantage with this procedure in that the separated particles clog the filter. Depending on the operating status of the Motors will be the case in just a few hours, so that

the filter becomes impermeable and the back pressure of the exhaust gas increases so much that operation is no longer possible is. To remedy this, the filter must have replaceable filter elements, which are then replaced and must be cleaned by burning out, blowing out or washing out. However, this is only practical with stationary engines and there only possible to a limited extent. Since this type of cleaning is very time-consuming, Attempts have also been made to increase the exhaust gas temperatures, possibly with an additional burner device Burn off the soot deposits on the filter in the area of the exhaust pipe during operation. The one on the However, soot accumulated on the filter surface leads to a high energy density when burned, so that overheating in the Filters and thus destruction of the filter material can occur if burned off quickly.

The invention is now based on the object of creating a device of the type described above, which enables continuous operation without the need to replace the filter inserts or add additional combustion energy to burn the filter.

This object is achieved according to the invention in that the exhaust line divided into at least two branch lines is that a filter cartridge is arranged in each branch line, that each branch line in the area of both Each end of the filter cartridge is provided with a shut-off valve that in the shut-off parts of each branch line An air line opens at both ends of the filter cartridge, each with a check valve is provided and which can be acted upon with air against the direction of flow of the exhaust gases in the filter and that in the direction of flow of the exhaust gases, the air line connected in front of the respective filter cartridge with the air line to the diesel engine leading supply line for the combustion air is connected. With this arrangement it is possible at

corresponding switching of the shut-off valves to act on only one filter cartridge with the exhaust gases to be cleaned and filter out the particles contained in the exhaust gases. Since the If the permeability of the filter cartridge in question is reduced, the exhaust gas flow can now be switched to the other filter cartridge will. At the same time, the filter cartridge, which is then put out of operation, is turned in the opposite direction to the flow with the exhaust gases flowing through with air and thereby cleaned of the deposited particles. Here is

exploited to advantage that the soot particles do not stick or burn during the operating times in question, but can be "rinsed off" from the filter material again with a relatively low air flow, and the detached particles are returned via the air line connected to the filter cartridge led into the combustion chamber of the engine ~? and burned there. By switching the function of the Fil

Continuous operation is possible with the cartridges on "Filter" or "Clean".

The decrease in permeability of the filter cartridge currently operated in the "Filter" function can be up to can be recognized to a certain extent by a decrease in the performance of the diesel engine. In an expedient configuration the invention, however, provides that seen in the flow direction of the exhaust gases, at least in front of each filter cartridge a pressure sensor is arranged. With the help of the pressure sensor and a corresponding display The decrease in the permeability of the filter cartridge operated in the "Filter" function becomes apparent very early on so that a function change can be made before a noticeable drop in performance of the diesel engine occurs. It is useful to design the pressure sensor as a differential pressure meter, with

the pressure in the exhaust pipe is measured in front of and behind each filter cartridge.
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The air lines can be acted upon in the "cleaning" function by an additional compressed air source, for example by connecting to the compressed air supply if the diesel unit in question has a compressor. In a preferred embodiment of the invention, however, it is provided that the air line connected behind the respective filter cartridge, seen in the flow direction of the exhaust gases, is connected to the supply line to the combustion air and is each provided with a shut-off valve, and that in the supply line, in Seen in the direction of flow of the air, an adjustable throttle is arranged in the area between the connection to the air lines leading to the filter cartridges and the connection of the air lines coming from the filter cartridges. This arrangement has the advantage that the action of the filter cartridges in the "cleaning" function takes place entirely via the combustion air required by the engine. However, in order to avoid that when switching from the "Filter" function to the "Clean" function, the particles that have accumulated on the filter cartridge suddenly and in high concentration enter the combustion chamber of the engine via the combustion air, the throttle ensures that when you switch to the "cleaning" function, the greater part of the combustion air required by the engine flows directly into the engine via the throttle, while only a small part flows through the filter cartridge to be cleaned and removes the accumulated particles. Then the flow cross-section in the supply line is continuously reduced with the help of the throttle,

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so that the amount of air flowing through the filter cartridge to be cleaned is continuously increased until practically all of the combustion air flows through the filter cartridge and this cleans off.

In an expedient embodiment of the invention it is provided that the shut-off valves both in the branch lines as also connected to actuators in the air lines

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are. This enables a remote control. The individual shut-off valves can each have their own actuator be provided, or according to an embodiment of the invention via a central actuator be mechanically coupled to one another, as the individual shut-off valves in the branch lines and in the air lines are assigned to one another in a defined manner with regard to their open or closed position. At a Function change can thus close the shut-off valves in the exhaust gas branch lines of one filter cartridge and the shut-off valves in the exhaust branch line of the other, now to be set to the "cleaning" function Filter cartridge must be opened. At the same time, the associated air lines are opened or closed accordingly. closed.

In an expedient embodiment of the invention it is also provided that the actuating drives have a pressure measuring device are controllable, which is connected to the pressure sensor assigned to each filter cartridge. This results in the possibility of an automatic operation, so that an ongoing monitoring by the operating personnel not applicable.

The throttle is expediently in the supply line provided with an actuator which opens the throttle completely when changing functions and then closes steadily, expediently in a predetermined period of time. This ensures that on the one hand the particles rinsed off the filter during the cleaning process are "dosed" returned to the combustion chamber on the other hand, however, after a certain period of time, the combustion air is completely passed through the filter and thus a complete cleaning of the filter is guaranteed.

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The invention is based on the circuit diagram for an embodiment explained in more detail.

In the case of a diesel engine 1, the exhaust line 2 is divided into two branch lines 3 and 4. In each of these two Branch lines are ie a filter cartridge 5 and 6 arranged. In the branch lines 3, 4 are in front of and behind each filter cartridge check valves 7, 8, 9, 10 arranged, with the help of which the filter cartridges can be shut off from the diesel engine. The shut-off valves 7, 8, 9, 10 are connected to an actuator 11 in such a way that when the shut-off valves are closed 7, 8 the shut-off valves 9, 10 are opened and vice versa.

Via a supply line 12, the diesel engine 1 is the Combustion air supplied. From the supply line 12 here each branch air lines 13, 14 and 15, 16 to Exhaust branch line 3 or 4 from. The air lines 13, 14 and 15, 16 each open between the shut-off valves 7, 8 or 9, 10 in the relevant branch line 3 or 4. Check valves are also in the air lines 13, 14, 15, 16 17, 18 and 19, 20 are arranged, which can also be controlled via actuators. In the example shown a central actuator 21 is in turn provided, via which the shut-off valves 17, 18, 19, 20 in the Are coupled manner that when the shut-off valves 17, 18 open, the shut-off valves 19, 20 close and vice versa .

The filter cartridge 5 and the filter cartridge 6 are now respectively a differential pressure meter 22 or 23 assigned, with the help of which the respective pressure in the branch line 3 or 4 before and after the filter cartridge 5 or 6 is measured when the respective branch line with exhaust gas is applied.

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In the supply line 12 is also between the branching off Air lines 18, 20 on the one hand and 17, 19 on the other hand, an adjustable throttle 24 is arranged, which has a Actuator 25 can be adjusted. 5

If the shut-off valves 9, 10 in the branch line 4 are now closed and the shut-off valves 7, 8 in the branch line 3 is opened, the exhaust gases from the diesel engine are only passed through the filter cartridge 5. As soon the differential pressure meter 22 indicates that a predetermined maximum deposit of particles on the filter cartridge 5 is present, a function change takes place in such a way that the shut-off valves 7, 8 are now closed and the shut-off valves 9, 10 are opened so that the filter cartridge 6 is now on the "Filter" function is switched.

In order to be able to clean the filter cartridge 5, the shut-off valves 17, 18 in the air lines 13, 14 are opened and the shut-off valves 19, 20 in the air lines 15, 16 are closed. Is now simultaneously via the stall drive 25, the initially fully open throttle in the supply line 12 is slowly closed, so in increasing extent the combustion air flowing into the engine via the air line 14 opposite to the direction of the Exhaust gas flow passed through the filter cartridge 5, so that the particles deposited on the filter are "washed away" and via the air line 13 back into the supply line 12 and thus into the combustion chamber of the Engine.

As soon as now via the differential pressure meter 23 for the filter cartridge 6 shows that the maximum permissible level of deposits has been reached, it is switched over again, so that now the filter cartridge 5 takes over the function of "filtering", while the filter cartridge 6 through Opening the valves 19, 20 in the air lines 15, 16

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and closing the valves 17, 18 in the air lines 13, 14 are switched to the "cleaning" function. During this switching process, the throttle 24 must first be fully opened each time via the actuator 25 so that the required amount of combustion air continues to be supplied to the engine. The actuator 25 however, it is designed so that it moves steadily from the fully open position within a given time the throttle cross-section is reduced, so that the "cleaning" function is increasingly being used Air flows through the filter cartridge and is cleaned in the process.

If one now forms the differential pressure meters 22 and 23 so, that they not only cause a display at the control station, but can also send a control signal, so the differential pressure gauges 22, 23 can be connected to a control circuit 26 so that each time the maximum permissible differential pressure with the differential pressure meter 22 or with the differential pressure meter 23 ■ above the actuators 11 and 21 the associated shut-off valves adjusted accordingly. At the same time, there is a control pulse for the actuator 25 of the throttle 24, which opens this completely. Depending on the structural Conditions and the spatial arrangement of the individual shut-off valves to one another can make this possible via a single central actuator can be opened or closed with the help of mechanical couplings. When using With a corresponding control circuit, however, it is also possible to provide each shut-off valve with its own actuator to be assigned, which is then controlled via the control circuit 26.

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Claims (7)

Description; Device for removing soot particles from the exhaust gases of a diesel engine Expectations; M J Device for removing soot particles from the exhaust gases of a diesel engine with an arranged in the exhaust pipe Filter, characterized in that the exhaust line (2) is in at least two branch lines (3.4) is divided that in each branch line (3.4) a filter cartridge (5, 6) is arranged that each branch line (3, 4) are each provided with a check valve (7, 8, 9, 10) in the area of both ends of the filter cartridges (5, 6) is that in the lockable part of each branch v device (3, 4) at both ends of the filter cartridges (5, 6) an air line (13, 14, 15, 16) opens which is each provided with a shut-off valve (18, 20) and counter to the flow direction of the exhaust gases in the filter cartridge (5, 6) can be acted upon with air and that seen in the flow direction of the exhaust gases at least the before respective filter cartridge (5, 6) connected air line (13, 15) with the one leading to the diesel engine (1) Telephone: (0221) 380238 Telegram: Inventator'Köln Telex: 8883555 max d f12 Postgirokonto-CCP Cologne (BLZ 37010050) Account no. 152251-500 Deutsche Bank AG Cologne (BLZ 37070060) Account No. 1236181 Connected supply line (12) for the combustion air is. 2. Device according to claim 1, characterized in that ° that seen in the flow direction of the exhaust gases at least a pressure sensor (22, 23) in front of each filter cartridge (5/6) is arranged. 3. Device according to claim 1 or 2, characterized gekennzeich- ¹ ^ net that also seen in the flow direction of the exhaust gases connected behind the respective filter cartridge (5, 6) connected to the air lines (14, 16) to the supply line (12) for the combustion air are and are each provided with a check valve (18, 20) and that in the supply line, seen in the direction of flow of the air, in the area between the air lines (14, 16) leading to the filter cartridges (5, 6) and the connection of the Filter cartridges (5, 6) coming air lines (13, 15) an adjustable throttle (24) is arranged. 20th 4. Device according to claims 1, 2 or 3, characterized characterized in that the shut-off valves (7 to 10) and (17 to 20) both in the branch lines (3, 4) and in the air lines (13, 14, 15, 16) are connected to actuators (11, 21). 5. Device according to claim 4, characterized in that the check valves are coupled to the actuators are that with a function change when closing or opening the check valves of a filter cartridge system the Open or close the shut-off valves of the other filter cartridge system. 6. Device according to one of claims 1 to 5, characterized in that the actuators have a pressure measuring device can be controlled, the pressure sensors (22, 23) assigned to each filter cartridge (5, 6) * connected is. 7. Device according to one of claims 1 to 6, characterized in that the throttle (24) in the supply line ⁵ (12) is provided with an actuator (25) which first fully opens the throttle (24) when the function changes and then steadily closes. 15 lg-ks 20 * '