Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
  • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
  • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D41/00—Regeneration of the filtering material or filter elements outside the filter for liquid or gaseous fluids
  • B01D41/04—Regeneration of the filtering material or filter elements outside the filter for liquid or gaseous fluids of rigid self-supporting filtering material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
  • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
  • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
  • F01N3/0233—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles periodically cleaning filter by blowing a gas through the filter in a direction opposite to exhaust flow, e.g. exposing filter to engine air intake

Definitions

• the present invention relates to a filter cleaning device for a particulate filter while mounted in an exhaust conduit of a diesel engine, wherein the filter is arranged to collect particulate matter from exhaust flowing from an upstream end to a downstream end of the filter.
• the filter cleaning device is mounted adjacent the filter and comprises a source of vacuum positioned to draw a cleaning fluid and waste material through the filter.
• a diesel particulate filter removes organic and inorganic particulate matter (PM) from the exhaust gas stream of an engine.
• the organic particulate is a complex blend of carbon, hydrogen and oxygen, and is a result of incomplete combustion of the diesel fuel in the cylinder.
• the inorganic portion of the PM has its source in the additives in the lubrication oil or fuel, and material eroded from the engine surfaces. Under optimal circumstances, the organic PM will fully combust during filter regeneration and thus leave the filter as gaseous CO2 and H2O.
• the inorganic component on the other hand, can not be converted to gaseous components, and is trapped in the filter as various oxides, commonly termed "ash". To maintain acceptable performance, the ash must be periodically removed from the filter to prevent it from clogging.
• DPF diesel particulate filters
• a simple way to clean a filter is with a compressed air hose.
• the hose is directed into the exit face of the filter, thus blowing the soot out of the wall in the reverse direction to which it was initially deposited (i.e., backwashing or back flushing).
• This method is imprecise, potentially dangerous (compressed air hazards), requires the full attention of an operator, and if improperly performed can lead to emission of PM from the filter end as well as a poorly cleaned filter.
• Heating the dirty filter in an oven to a high temperature can effectively remove the carbon-based particles, but requires significant energy input and does not remove the inorganic ash. After a heating cycle, the cool down period is significant, and the ash must be removed through vacuuming or washing.
• a large blower can be used with the filter in the reverse flow orientation. Blowers of the appropriate size are expensive and noisy, and the technique may not remove the tightly bound material. Additionally, as the cleaning process progresses, the flow will preferentially go through the cleanest portion (i.e., areas with least pressure drop).
• US 5 930 994 shows a combination of valve settings can start the back-flush of one of the filters i.e., the direction of gas flow is reversed and flows to push the soot out of the filter.
• the reversed air flow can be heated to allow soot to be burned off as the air passes the DPF.
• US 5 725 618 discloses a method which 'backwashes' a DPF to remove the particulate and ash collected in the filter.
• the backwashing occurs while the device is on the vehicle, and an impact air valve is used to provide a pressure wave to dislodge the particulate matter.
• the filter unit is rotated in order to expose a predetermined sector of the filter unit to the air stream supplied by the impact air valve.
• the above “back-flush” methods have the disadvantage that the ash from the lubricating oil never leaves the filter system, as back-flushed ash from one element flows into another element, and manual cleaning will still be required.
• a further method of cleaning a DPF involves a device using a rotating electrical heating element. A portion of the exhaust gas bleeds through a rotating arm and flows over the heating element. The combination of low flow rate and high temperature improves the chance of regeneration.
• US 5 116 395 discloses a dust collector with on-board programmable cleaning control.
• a rotating arm with a plurality of nozzles mounted upon it provides the back-flushing flow, thus causing the particulate to be removed from the bag surface and settle into a collection chamber.
• the control system operates the arm and nozzles to produce jets of cleaning fluid above the various bag units.
• the arm also contains a sensor for determining the dirtiness of each filter element (a pitot tube is suggested).
• the system described in the patent has several design elements which make it unsuitable for use in diesel particulate filter applications.
• DPFs are much smaller than dust collectors, and the nozzle designs in the above dust collector are specialized for large filters.
• a typical DPF is between 15 cm and 32 cm in diameter.
• the dust collector shown in the patent appears have a relatively large diameter.
• Second, DPFs can have many thousand cells, and thus focusing air on each individual cell is impractical. Other similar designs for dust collectors have the same shortcomings.
• An object of the present invention is to provide solutions for at least some of the drawbacks discussed above.
• some embodiments of the present invention provide an improved filter cleaning device having means for effectively removing and collecting ash from the DPF, as well as means providing an automatic movement of the cleaning device.
• the object of the invention is achieved by a filter cleaning device according to the invention and a method for cleaning such a filter cleaning device, having the characteristic features defined in the appended claims.
• the invention relates to a filter cleaning device for a particulate filter mounted in an exhaust conduit of a diesel engine, wherein the filter is arranged to collect particulate matter from exhaust flowing from an upstream end to a downstream end of the filter.
• the filter is preferably, but not necessarily, of the monolith type, having multiple channels for trapping particulate matter in the exhaust from a combustion engine.
• the filter cleaning device is mounted adjacent the filter in order to allow the filter to be cleaned in situ.
• the filter cleaning device comprises a source of vacuum positioned to draw a cleaning fluid and waste material through the filter, wherein a vacuum device is provided for applying a source of vacuum to an enclosed space at the upstream end of the filter. At least one actuator is provided for moving the vacuum device relative to the filter.
• the filter cleaning device may further comprise a controller with logic for instructing said actuator to automatically move at least a portion of the vacuum device along a path across a surface of the filter to draw the fluid through the filter.
• a collector may be positioned to receive waste material released from the filter during a filter cleaning event.
• the filter cleaning event occurs when the engine is switched off.
• the vacuum device When a cleaning cycle is started the vacuum device may be located in a 'home' or initial position, to which the cleaning device is returned after a completed cycle.
• a valve connected to the vacuum device is switched to provide suction power to the vacuum device.
• the controller is arranged to instruct the actuator to move a nozzle of the vacuum device adjacent the surface of the filter.
• the nozzle of the vacuum device may be held adjacent to or at a predetermined distance from the surface of the filter. According to a preferred embodiment the nozzle is held in contact with the filter surface.
• the nozzle may comprise a suction mask to focus the suction force on the filter. In this way the nozzle may be connected to a single conduit or at most to a limited number of adjacent conduits at one time.
• the filter cleaning device may be mounted vertically, horizontally or at any angle there between without affecting the function thereof.
• the vacuum device may be coupled to a pulsing source of vacuum for pulsing the cleaning pressure and fluid flow rate through the filter.
• the nozzle of the vacuum device may be moved along a predetermined path over the surface of the filter to provide a substantially uniform level of cleaning of the filter.
• the nozzle may be moved across the surface of said filter in a predetermined pattern.
• the nozzle may be moved in substantially straight lines across the surface of the filter along two perpendicular axes in the plane of the surface of the filter.
• the nozzle may be moved across the surface of the filter along a path controlled by a guide in the shape of a labyrinth.
• the guide may comprise a fixed or a replaceable/removable unit located at one or both ends of a filter.
• a fixed guide may be mounted during assembly of a filter and will only require a relatively small opening for allowing access for a filter cleaning device.
• at least one end wall of the filter may be removed prior to a cleaning operation, whereby a guide can be placed adjacent to the filter.
• the end wall may be a part of a canning enclosing one or more filter units. This provides easy access to the guide and filter for a filter cleaning device. Consequently the guide may be arranged to be removed from the filter during periods of normal operation of said filter.
• the nozzle may be moved across the surface of the filter along a rotational path or a spiral path.
• the actuator may also be arranged to rotate a rectangular nozzle about the central axis of a filter having a substantially cylindrical shape.
• the described movement of the cleaning device may be achieved by coupling the nozzle to an arm that is moved by said actuator that guides the nozzle across the surface of the filter.
• a cleaning fluid delivery device for supplying a cleaning fluid from a fluid source is provided opposite the vacuum device at the downstream end of the filter.
• the vacuum device and the cleaning fluid delivery device are moved together, so that they are in fluid connection through the same conduit or conduits of the filter at all times.
• the cleaning fluid delivery device may be controlled by the actuator for the vacuum device or by a separate second actuator.
• the controller is arranged to synchronize the movements of the first and second actuators.
• the controller may be arranged to instruct the second actuator to move a nozzle of the cleaning fluid delivery device adjacent the surface of the filter.
• the nozzle of the fluid delivery device may be held adjacent to or at a predetermined distance from the surface of the filter. According to a preferred alternative the said nozzle is held in contact with the filter surface.
• the nozzle of the vacuum device and the fluid delivery device may be mounted to a plunger attached on a translation arm controlled by the actuator.
• the nozzles may be pushed and held in contact with the face of the filter by a spring in the translation arm.
• the nozzles themselves may be made of a variety of materials including but not limited to an abrasion resistant plastic. These are meant to slide across the surface of the filter without damaging it, and are easily replaced when needed.
• the nozzle of the vacuum device may have a cross-sectional area that is equal to or larger than the corresponding area of the nozzle of the cleaning fluid delivery device.
• the cross-sectional areas of the said nozzles area measured at a position adjacent the respective surfaces of the filter.
• the cross-sectional area of the nozzle for the vacuum device is larger than the area of the nozzle of the cleaning fluid delivery device. This is to ensure that all the cleaning fluid supplied to the filter is extracted from the filter as the opposing nozzles are moved across the filter.
• the controller may be arranged to pulse the cleaning pressure and fluid flow rate from the fluid delivery device.
• the fluid delivery device is connected to a pulsing fluid source for pulsing the cleaning pressure and fluid flow rate through the filter.
• the fluid delivery device may also be arranged to provide high pressure cleaning fluid to different regions of the filter face and or to vary the pressure and/or flow rate supplied to different regions of the filter.
• the filter cleaning device comprises a source of vacuum positioned to draw a cleaning fluid and waste material through the filter, wherein a vacuum device is provided for applying a source of vacuum to an enclosed space between the upstream end of the filter unit to be cleaned and an additional filter unit or a catalytic cleaning unit.
• a vacuum device is provided for applying a source of vacuum to an enclosed space between the upstream end of the filter unit to be cleaned and an additional filter unit or a catalytic cleaning unit.
• a cleaning fluid delivery device for supplying a cleaning fluid from a fluid source is provided at the downstream end of the filter.
• the cleaning fluid used is air
• the air can be drawn from the exhaust conduit downstream of the filter.
• Cleaning fluid may also be drawn from a conduit connected a supply of air or other gaseous cleaning fluid attached to the exhaust conduit downstream of the filter.
• a cleaning fluid delivery device for supplying a cleaning fluid from a fluid source is provided adjacent the filter at the downstream end of the filter.
• the cleaning fluid delivery device may be controlled by an actuator.
• a controller is arranged to instruct the actuator to move a nozzle of the cleaning fluid delivery device adjacent the surface of the filter.
• the nozzle of the fluid delivery device may be held adjacent to or at a predetermined distance from the surface of the filter. According to a preferred embodiment the said nozzle is held in contact with the filter surface.
• the vacuum device may be connected via a conduit having a central axis located at a tangent relative to a central geometric axis through the filter, so as to create a circulating flow of gaseous fluid in the enclosed space.
• the filter cleaning device may be mounted vertically, horizontally or at any angle there between without affecting the function thereof.
• the filter unit When using liquid or a combination of gaseous and liquid fluid for cleaning the filter it may be preferable to arrange the filter unit so that the source of vacuum may be connected to a lower position of the enclosed space.
• the filter cleaning device may further comprise a controller with logic for instructing said actuator to automatically move at least a portion of the vacuum device along a path across a surface of the filter to draw the fluid through the filter.
• a second actuator may be provided opposite the first actuator at the downstream side of the filter for moving a cleaning fluid delivery device.
• the cleaning fluid may comprise any suitable substance. When a vacuum device is used separately, then the fluid may be air that is drawn from the downstream side of the filter.
• the fluid When a cleaning fluid delivery device is used in combination with the vacuum device, the fluid may be in either gaseous or liquid form.
• gaseous fluids may be air, ozone (O 3 ) or nitrogen dioxide (NO 2 ) or similar gases that will oxidize soot at relatively low temperatures.
• Liquid fluids for deep cleaning of particulate filters may contain various chemicals, such as organic acids. Examples of organic acids for this purpose are citric acid, oxalic acid, tartaric acid and acetic acid.
• Other fluids may be water, possibly used as steam, or alcohol.
• the gaseous and /or liquid fluids may be heated by a suitable heating means, such as an electric heater, before being introduced into the filter.
• a suitable heating means such as an electric heater
• the filter itself may be heated prior to the cleaning process.
• the fluid may be drawn at a fixed flow rate or pulsed in short bursts through the filter by using the vacuum device located upstream of the filter.
• the fluid may be pressurized and supplied at a fixed flow rate or pulsed through the cleaning fluid delivery device located downstream of the filter. It is also possible to pulse a mixture of gaseous and liquid fluid through the filter.
• a pulsed flow may be achieved by, for instance, a positive displacement compressor.
• the cleaning process may comprise one or more steps.
• a single step process may involve supplying a cleaning fluid in gaseous, fluid or mixed gaseous and fluid form to clean the filter.
• a first step may involve supplying a cleaning fluid in fluid or mixed gaseous and fluid form to clean the filter, followed by a second step where a gaseous fluid is used to dry the filter.
• a gaseous cleaning fluid is used to perform a first cleaning step and a liquid cleaning fluid is used to perform a second cleaning step.
• the first and second steps may be followed by a third step where a gaseous fluid is used to dry the filter.
• the invention is not limited to processes comprising the above steps, as the combination of gaseous and/or liquid fluids and the number and order of processing steps may vary between different types of particulate filters.
• the collector for receiving waste material released from the filter may be arranged to separate the gaseous and liquid components of the cleaning fluid as the supply of fluid in gaseous or liquid form is alternately supplied to the fluid delivery device.
• the collector may be provided with suitable filters, such as High Efficiency Particulate Air (HEPA) and/or Ultra Low Penetration Air (ULPA) filters.
• HEPA High Efficiency Particulate Air
• ULPA Ultra Low Penetration Air
• the design of the collection system used upstream of the DPF may use special filtering techniques. Widely available HEPA filters are rated to trap 99.97% of airborne particles 300 nanometers and larger. The next, and far more expensive, grade is the ULPA filter. This class of filters traps finer particles: 99.99% of particles 120 nanometers and larger.
• Diesel particulate matter may be composed of particles which are smaller than the lower bounds of these filters, and it is unclear whether particle agglomeration or filtering by the layer of PM within a HEPA or ULPA filter will provide sufficient removal of the finest particles.
• a novel improvement to the design is to locate a wall-flow DPF in the exhaust stack of the vacuum system, which will be capable of removing nearly all of the particulates.
• the invention further relates to a method for cleaning a particulate filter as described above.
• the method applies to a filter cleaning device comprising a source of vacuum positioned to draw a cleaning fluid and waste material through the filter, wherein a vacuum device is provided for applying a source of vacuum to an enclosed space at the upstream end of the filter.
• At least one actuator is provided for moving the vacuum device relative to the filter.
• the filter cleaning device may further comprise a controller with logic for instructing said actuator to automatically move at least a portion of the vacuum device along a path across a surface of the filter to draw the fluid through the filter.
• the method may comprise the steps of: a) using a vacuum device for applying a source of vacuum to the upstream end of the filter draw a cleaning fluid and waste material through the filter; b) controlling an actuator to automatically move at least a portion of the cleaning fluid delivery device along a path across a surface of the filter to draw the cleaning fluid through the filter; c) using a collector positioned to receive waste material released from the filter during a filter cleaning event.
• the method may also involve moving a nozzle of the vacuum device adjacent the surface of the filter.
• the method involves holding the nozzle of the vacuum device in contact with the surface of the filter.
• a substantially uniform level of cleaning of the filter may be achieved by moving a nozzle on the vacuum device along a predetermined path over the surface of the filter.
• the method may also use a nozzle comprising a suction mask with the delivery device to focus suction on the filter.
• a uniform level of cleaning of the filter may be achieved by moving the nozzle on the vacuum device along a guide for controlling the predetermined path.
• the guide may be mounted fixed in the filter, but may also be removable from the filter during normal operation of the filter. The latter may be achieved by removing at least one end wall of the filter or the canning surrounding one or more filter units and placing the guide adjacent to the filter prior to a cleaning operation.
• This feature can be incorporated to determine if the filter cleaning process is complete. This feature may be one or more pressure sensors.
• One pressure sensor may be located in the enclosed space, which sensor is connected to a monitoring system that may be part of the controller.
• a monitoring system that may be part of the controller.
• a fluid flow sensor positioned to determine if a section of filter adjacent a nozzle is more or less clogged with particulate mater than regions of the filter around the section.
• the fluid flow sensor may monitor the fluid flow through the vacuum device or the cleaning fluid delivery device.
• the fluid flow may be monitored continuously during the cleaning process or intermittently as the cleaning device moves through a pre-programmed set of positions, and optionally monitors the flow rate at each position.
• the state of the filter may also be monitored during normal operation of the filter, whereby pressure sensors may be used to monitor to pressure drop for the exhaust passing through the filter. When the pressure drop exceeds a predetermined limit, it is determined that a filter cleaning is to be carried out. The cleaning process may be carried out the next time the engine is stopped. Alternatively, the driver is alerted by the monitoring system. This may allow the driver to plan the driving activity to permit a cleaning process to be carried out, or to manually initiate the process when the engine is stopped.
• the monitoring system can monitor for filter failure by scanning for pressure drops which are too low. If the pressure drop is lower than that of a clean filter then this indicates that there is a leak in the system.
• Figure 1 shows a schematic illustration of a particulate filter with a filter cleaning device according to a first embodiment of the invention
• Figure 2 shows a schematic illustration a filter cleaning device according to a first alternative version of the first embodiment the invention
• Figure 3 shows a schematic illustration a filter cleaning device according to a second alternative version of the first embodiment the invention
• Figure 4 shows a schematic illustration a filter cleaning device according to a third alternative version of the first embodiment the invention
• Figs 5A-C show a number of examples of possible guide shapes for controlling the nozzle movements
• Figure 6 shows a schematic illustration of a particulate filter with a filter cleaning device according to a second embodiment of the invention
• Figure 7 shows a schematic illustration a filter cleaning device according to a first alternative version of the second embodiment the invention.
• FIG. 1 shows a schematic illustration of a diesel particulate filter (DPF) 11 provided with a filter cleaning device 12 according to a first embodiment the invention.
• the DPF 11 is connected to an engine (not shown) via an first exhaust conduit A upstream of the DPF 11 and to an exhaust outlet via a second exhaust conduit B.
• the figure shows a first example of the first embodiment, wherein the filter cleaning device 12 comprises a pump 13 providing a source of vacuum for drawing a cleaning fluid F, in this case air, and waste particulate material dislodged from multiple, parallel channels making up a filter unit 14 through the DPF 11.
• the filter cleaning device 12 further comprises a vacuum device in the form of a nozzle 15 provided for applying vacuum from the pump 13 to the upstream end of the filter unit 14.
• An actuator 16 is provided for moving the nozzle 15 relative to the surface of the filter unit 14 by means of an arm 17.
• the nozzle 15 is connected to the pump 13 via a first conduit 18 arranged along the arm 17 and through the actuator 16 and a second conduit 19 from the actuator to the pump 13.
• the filter cleaning device also comprises an electronic control unit ECU with logic for instructing said actuator 16 to automatically move the nozzle 15 along a predetermined path across a surface of the filter unit 14 to draw the air F through the filter unit 11.
• a collector C is positioned adjacent the pump 13 to receive waste material released from the filter during a filter cleaning cycle.
• FIG 2 shows a schematic illustration of a diesel particulate filter (DPF) 11 provided with a filter cleaning device according to a first alternative version of the first embodiment the invention.
• a filter cleaning device 12 comprises a pump 13 providing a source of vacuum for drawing a cleaning fluid and waste particulate material dislodged from multiple, parallel channels making up a filter unit 14 through the DPF 11.
• the filter cleaning device 12 further comprises a vacuum device in the form of a nozzle 15 provided for applying vacuum from the pump 13 to the upstream end of the filter unit 14.
• a first actuator 16 is provided for moving this first nozzle 15 relative to the surface of the filter unit 14 by means of an arm 17.
• the nozzle 15 is connected to the pump 13 via a first conduit 18 arranged along the arm 17 and through the actuator 16 and a second conduit 19 from the actuator to the pump 13.
• the filter cleaning device also comprises an electronic control unit ECU with logic for instructing said actuator 16 to automatically move the nozzle 15 along a predetermined path across a surface of the filter unit 14 to draw the cleaning fluid through the filter unit 11.
• a collector C is positioned adjacent the pump 13 to receive waste material released from the filter during a filter cleaning cycle.
• the device shown in Figure 2 differs from that of Figure 1 in that a cleaning fluid delivery device 20 comprising a second nozzle 21 is provided at the downstream end of the filter, directly opposite the first nozzle 15 of the vacuum device.
• the second nozzle 21 is arranged to supply a cleaning fluid under pressure from a fluid source (not shown) by means of a pump 22.
• This pump can supply the cleaning fluid at a constant or variable pressure, as well as supplying a pulsed flow, depending on the type of cleaning fluid.
• the example in Figure 2 shows an embodiment for supplying a single gaseous or liquid cleaning fluid.
• the second nozzle 20 can also be arranged to supply more that one cleaning fluid, such as a gas and a liquid, from separate liquid sources using the same or separate pumps (not shown).
• gas and liquid can be supplied alternately during different steps of the cleaning process.
• the process can involve a first step of flushing the filter unit with nitrous dioxide to oxidize soot particles.
• the filter unit is flushed with a liquid organic acid to clean the channels through the filter.
• the filter unit can be dried using air.
• the type of collector used is dependent on what or which cleaning fluid or combinations of fluids are used.
• the collector can contain one or more filters arranged to collect particles of different sizes.
• the nozzle 15 of the vacuum device 12 and the nozzle 21 of the cleaning fluid delivery device 20 are moved together, so that they are in fluid connection through the same channel or channels of the filter unit 14 at all times.
• the cleaning fluid delivery device 20 is controlled by a second actuator 23 in the same way as the first actuator 16.
• the actuator 23 is provided for moving the nozzle 21 relative to the surface of the filter unit 14 by means of an arm 24.
• the electronic control unit ECU is arranged to synchronize the movements of the first and second actuators 16, 23.
• the electronic control unit ECU is arranged to instruct the second actuator 23 to move the second nozzle 21 adjacent the surface of the filter unit 14.
• the first and second nozzles 15, 21 are held in contact with the filter surface.
• the second nozzle 21 is connected to the pump 22 via a first conduit 25 arranged from the pump 22 to and through the actuator 23.
• a second conduit 26 is arranged from the actuator 23 and along the arm 24, to the second nozzle 21.
• the first and second nozzles When in operation, the first and second nozzles are located at an initial position, facing each other on opposite sides of the filter unit.
• the electronic control unit ECU is arranged to synchronize the movement of the first and second actuators 16, 23 as they move across their respective surface.
• the second pump 22 is operated to supply a predetermined volume of cleaning fluid.
• the first pump 13 is operated to remove at least the corresponding volume of fluid, whereby the particulate matter removed from the filter unit 14 is separated from the fluid in the collector C.
• FIG 3 shows a schematic illustration of a diesel particulate filter (DPF) provided with a filter cleaning device according to a second alternative version of the first embodiment the invention.
• DPF diesel particulate filter
• the filter cleaning device in Figure 3 differs from the device of Figure 2 in that it comprises a filter cleaning device having a vacuum device in the form of a first nozzle 31 provided for applying vacuum from the pump 13 to the upstream end of the filter unit 14.
• the nozzle 31 comprises an elongated rectangular section extending in a radial direction from the central axis of the filter unit 14.
• a first actuator 32 is provided at the central axis of the DPF 11 for moving this first nozzle 31 in a circular path relative to the surface of the filter unit 14 by means of a rotary arm 33.
• the nozzle 31 is connected to the pump 13 via a first conduit 34 arranged along the arm 33 and through the actuator 32 and a second conduit 35 from the actuator to the pump 13.
• the filter cleaning device also comprises an electronic control unit ECU with logic for instructing said actuator 32 to automatically move the nozzle 31 along circular path across a surface of the filter unit 14 to draw the cleaning fluid through the filter unit 11.
• a collector C is positioned adjacent the pump 13 to receive waste material released from the filter during a filter cleaning cycle.
• the cleaning device shown in Figure 3 also comprises a cleaning fluid delivery device 36 comprising a second nozzle 37 is provided at the downstream end of the filter, directly opposite the first nozzle 31 of the vacuum device.
• a second actuator 38 rotates the second nozzle across the downstream surface of the filter unit 14.
• the electronic control unit ECU ensures that the movement of the first and second nozzles is synchronized during each cleaning cycle.
• the second nozzle 37 is arranged to supply a cleaning fluid under pressure from a fluid source (not shown) by means of a pump 39. This pump can supply the cleaning fluid at a constant or variable pressure, as well as supplying a pulsed flow, depending on the type of cleaning fluid.
• FIG 4 shows a schematic illustration of a diesel particulate filter (DPF) provided with a filter cleaning device according to a third alternative version of the first embodiment the invention.
• the device according to Figure 4 is similar to that of Figure 2.
• the figure shows a pump 13 providing a source of vacuum for drawing a cleaning fluid and waste particulate material dislodged from multiple, parallel channels making up a cylindrical filter unit 14 through the DPF 11.
• the filter cleaning device 12 further comprises a vacuum device in the form of a nozzle 15 provided for applying vacuum from the pump 13 to the upstream end of the filter unit 14.
• a first actuator 16 is provided for moving this first nozzle 15 relative to the surface of the filter unit 14 by means of an arm 17.
• the nozzle 15 is connected to the pump 13 via a first conduit 18 arranged along the arm 17 and through the actuator 16 and a second conduit 19 from the actuator to the pump 13.
• the filter cleaning device also comprises an electronic control unit ECU with logic for instructing said actuator 16 to automatically move the nozzle 15 along a predetermined path across a surface of the filter unit 14 to draw the cleaning fluid through the filter unit 14.
• a collector C is positioned adjacent the pump 13 to receive waste material released from the filter during a filter cleaning cycle.
• the nozzle 15 of the vacuum device 12 and a nozzle 21 of a cleaning fluid delivery device 20 are moved together, so that they are in fluid connection through the same channel or channels of the filter unit 14 at all times.
• the cleaning fluid delivery device 20 is supplied by a pump 22 and controlled by a second actuator 23 in the same way as the first actuator 16.
• the actuator 23 is provided for moving the nozzle 21 relative to the surface of the filter unit 14 by means of an arm 24.
• the electronic control unit ECU is arranged to synchronize the movements of the first and second actuators 16, 23.
• the electronic control unit ECU is arranged to instruct the second actuator 23 to move the second nozzle 21 adjacent the surface of the filter unit 14.
• the first and second nozzles 15, 21 are held in contact with the filter surface.
• the second nozzle 21 is connected to the pump 22 via a first conduit 25 arranged from the pump 22 to and through the actuator 23.
• a second conduit 26 is arranged from the actuator 23 and along the arm 24, to the second nozzle 21.
• the controller may be arranged to pulse the cleaning pressure and fluid flow rate from the fluid delivery device.
• the fluid delivery device is connected to a pulsing fluid source for pulsing the cleaning pressure and fluid flow rate through the filter.
• the fluid delivery device may also be arranged to provide high pressure cleaning fluid to different regions of the filter face and or to vary the pressure and/or flow rate supplied to different regions of the filter.
• the electronic control unit ECU can be connected to the vacuum pump 13 and the fluid supply pump 22 in order to control the fluid flow.
• the filter cleaning device can be arranged to supply more that one cleaning fluid, such as a gas and a liquid, from separate liquid sources using the same or separate pumps (not shown). In this way gas and liquid can be supplied alternately during different steps of the cleaning process.
• the first and second nozzles When in operation, the first and second nozzles are located at an initial position, facing each other on opposite sides of the filter unit.
• the electronic control unit ECU is arranged to synchronize the movement of the first and second actuators 16, 23 as they move the nozzles 15, 21 in their respective guide 41 , 42 across surface of the filter.
• the nozzle or nozzles in filter cleaning devices described in the above embodiments may be located in a 'home' or initial position. After a completed cycle the nozzle or nozzles are returned to the initial position.
• Figure 4 shows a guide comprising fixed guides 41 , 42 located at both ends of a filter unit 14.
• a fixed guide is mounted during assembly of the DPF 11 and will only require a relatively small opening for allowing access for the filter cleaning device.
• at least one end wall of the DPF 11 may be removed (not shown) prior to a cleaning operation, whereby a guide can be placed adjacent to the filter at one or both ends thereof.
• the latter solution provides easy access to the guide and filter for a filter cleaning device.
• Figures 5A-5C show a number of examples of possible guide shapes for controlling the nozzle movements.
• Figure 5A shows a guide 51 having a spiral shape, wherein the nozzle is moved in a first spiral track 52 from the periphery towards the centre of the filter unit.
• FIG. 5B shows an example of a guide 54 in the shape of a labyrinth intended for use with a filter unit with a cylindrical cross-section.
• Figure 5C shows an example of a guide 55 in the shape of a labyrinth intended for use with a filter unit with a square cross-section. Note that the invention is not limited to the above examples.
• FIG. 6 shows a schematic illustration of a diesel particulate filter 61 provided with a filter cleaning device 62 according to a first alternative version of a second embodiment of the invention.
• the filter cleaning device 62 comprises a source of vacuum 63 positioned to draw a cleaning fluid and waste material through at least one filter unit in the filter, wherein the vacuum device 63 is provided for applying a source of vacuum to an enclosed space 64 between the upstream end of a first filter unit 65 to be cleaned and an additional, second filter unit 66.
• the source of vacuum need only be connected to the space 64 between the units 65, 66.
• a collector C is positioned to receive fluid and waste material released from the filter during a filter cleaning event.
• the filter assembly is connected to the exhaust conduit A from the engine, which conduit may be considered to be a substantially closed volume.
• the pressure in this closed volume will be substantially the same as the pressure in the enclosed space. Because of the vacuum present in the enclosed space, cleaning fluid will not leak out through the second filter unit located upstream of the first filter unit.
• the cleaning fluid is air drawn from an exhaust conduit B downstream of the particulate filter 61.
• a suitable gaseous cleaning fluid may be injected from a port 68 in the canning 67 downstream of the particulate filter 61.
• the port 68 can be supplied from a separate source 69 of fluid.
• FIG. 7 shows a schematic illustration of a diesel particulate filter 71 provided with a filter cleaning device 72 according to a second alternative version of the second embodiment the invention.
• the filter cleaning device 72 comprises a source of vacuum 73 for drawing a cleaning fluid and waste material through at least one filter unit the filter, wherein the vacuum device 73 is provided for applying a source of vacuum to an enclosed space 74 between the upstream end of a first filter unit 75 to be cleaned and an additional, second filter unit 76.
• the particulate filter 71 is mounted in a filter assembly having a canning 77 comprising multiple units and the source of vacuum is connected to the space 74 between the units 75, 76.
• a collector C is positioned to receive fluid and waste material released from the filter during a filter cleaning event.
• the filter assembly is connected to the exhaust conduit A from the engine.
• the pressure in this closed volume will be substantially the same as the pressure in the enclosed space. Because of the vacuum present in the enclosed space, cleaning fluid will not leak out through the second filter unit located upstream of the first filter unit. At least a part of the cleaning fluid is air drawn from an exhaust conduit B downstream of the particulate filter 71.
• the filter cleaning device further comprises a cleaning fluid delivery device 78 for supplying a cleaning fluid under pressure from a fluid source in the form of a pump 79 is provided at the downstream end of the first filter unit 75.
• the cleaning fluid delivery device 78 is controlled by an actuator 80.
• a controller ECU is arranged to instruct the actuator 80 to move a nozzle 81 of the cleaning fluid delivery device 78 adjacent the downstream surface of the filter 75.
• the nozzle 80 of the fluid delivery device is held in contact with the said filter surface.
• the nozzle 81 is connected to the pump 79 via a first conduit 82 arranged from the pump 79 to and through the actuator 80.
• a second conduit 83 is arranged from the actuator 80 and along an arm 84, to the nozzle 81.
• the vacuum device can be connected to the canning via a conduit having a central axis located at a tangent relative to a central geometric axis through the filter. This creates a circulating flow of gaseous fluid and waste material in the enclosed space and ensures that the waste material is removed from said space.
• the filter cleaning device may be mounted vertically, horizontally or at any angle there between without affecting the function thereof.
• the filter unit may be preferable to arrange the filter unit in a substantially horizontal position with the source of vacuum connected to a lower position of the enclosed space.
• the filter cleaning device may further comprise a controller with logic for instructing said actuator to automatically move at least a portion of the vacuum device along a path across a surface of the filter to draw the fluid through the filter.
• a second actuator may be provided opposite the first actuator at the downstream side of the filter. In the latter case the movements of the cleaning fluid delivery device and the vacuum device would be synchronized.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Processes For Solid Components From Exhaust (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)

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• 2006
  • 2006-10-31 EP EP06812958A patent/EP2082121A4/de not_active Withdrawn
  • 2006-10-31 WO PCT/SE2006/001234 patent/WO2008054262A1/en active Application Filing

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