FR2589194A1 - FILTER FOR THE SEPARATION OF SOLID PARTICLES CONTAINED IN EXHAUST GASES OF DIESEL ENGINES - Google Patents

Abstract

A.FILTER FOR THE SEPARATION OF SOLID PARTICLES CONTAINED IN THE EXHAUST GASES OF DIESEL ENGINES. B. FILTER CHARACTERIZED IN THAT THE FILTER ELEMENT 32 IS MOBILE MOUNTED IN THE CASE 10, AND IN THAT A RATCHET AND PENDULUM MECHANISM ENSURES THE DRIVING OF THE FILTER ELEMENT 32, CONTROLLED BY THE MOVEMENT OF ' ACCELERATION OR BRAKING OF THE VEHICLE. C. THE INVENTION RELATES TO A FILTER FOR THE SEPARATION OF SOLID PARTICLES CONTAINED IN THE EXHAUST GASES OF DIESEL ENGINES.

Description

"Filter for the separation of solid particles contained

  in diesel engine exhaust ".

  The present invention relates to a filter for separating solid particles contained in the exhaust gas of a diesel engine, a filter composed of a filter element which retains the particles contained in the gas stream passing through this filter element,

  this element being housed in a housing.

  Many embodiments of such filters are known (DE-A-953 753). These filters consist of

  usually a housing with an exhaust gas inlet

  and an exhaust gas outlet and between them

  one or more porous filter bodies joined together

  to the boot maker. Such filters must be clearly

  or regenerated to maintain their separating power.

  The present invention aims to develop a filter of the above type which has a separating power as high as possible and which can

  be regenerated or cleaned continuously.

  For this purpose, the invention relates to a filter of the above type, characterized in that the element

  filter is mounted in the casement.

  Thanks to the mobile filter element,

  there are many possibilities for applying

  regeneration plants that can provide regeneration

  tion of the filter element continuously or inter-

  during the operation of the internal combustion engine. So, the filter element always has its

  optimum separating power while generating

  losses in the exhaust pipe system. The filter element may be in the form of a rotary tube. This embodiment offers the advantage of being able to produce the filter element in any form of expanded ceramic, in the form of a fiber filter, in the form of a net

metallic or the like.

  A preferred embodiment of the filter element is to provide a rotating endless band. Such a band-shaped filter element may for example be made in the form of a metal knit which is stretched over two return rollers and which

  can be trained continuously intermittently.

  To combine the resistance and the optimal separating power

  Even so, the filter element can be made of a thin, flexible metal mesh that is sintered on a refractory metal fiber fleece. The flexible metal net is made to withstand the expected stresses while the filter properties are provided by the fleece. The metal net serves at the same time to support the fleece, so that it retains its properties

  filter, permanently, despite its rotational movement.

  The filter element according to the invention can be associated with a box made in the form of a multi-chamber noise damper, the element of

  filter at least partially surrounding one of the chambers.

  This makes it possible to integrate the filter function and dampen

  noise in one set. The filter element surrounds the walls of the corresponding chamber through which the exhaust gas flows to prevent the passage of

uncleaned gas.

8 9 194

  A constructionally simple and space-saving embodiment consists of a

  a single box with an inlet for the exhaust gases

  ment. This case can be cylindrical in shape with circular section, rectangular or generally polygonal or oval. In the plane of the largest diameter of the main housing, there is a second chamber which is surrounded

  filter element and the shape of which depends on the

  sation of the filter element. For the endless belt filter element, the second chamber preferably has the shape of a flattened square. The partition between the main casing and the second chamber can be formed directly by the filter element or by a sieve sheet

  on which the filter element is based.

  Finally, a third chamber can be provided in the form of a gas collector

  exhaust and which is equipped with the exhaust gas

  being connected to the second chamber by a resonant choke element. The exhaust manifold may be provided inside or outside the main housing. The shape of such a structure can be adapted

  to the available volume. We can thus have a box of fil-

  large area but at low height, which allows an exhaust gas over a large area while having a low constructive height for the

mounting the filter.

  The advance movement of the filter can be done continuously but also intermittently,

  regulated or unregulated according to the regeneration system

  used for the filter. For a controlled drive, whether continuous or discontinuous, it is interesting to have an electric motor. In the case of an unregulated batch movement, a ratchet and pendulum mechanism may preferably be used. Such a system preferably applies to vehicles, because thanks to the appropriate mounting of the pendulum

  the mass of it is subject to the accelerating movement

  tion of the vehicle and drives the ratchet mechanism thereby causing each time a certain advance of the filter element. This system is well suited to the extent that it does not consume external energy and that the pendulum movement is ensured by the operation of the vehicle which performs at relatively short intervals

  accelerations and braking.

  Regeneration of the filament element

  can be optimally achieved through its movement

  by respecting several points of view. Thus one can first freely choose the layout of the regeneration plant, in space since this

  installation only acts on a part of the filter element.

be rotatable.

  When using burners to regenerate, a separation between

  rooms through which the exhaust gases enter the bowl-

  tier and the combustion chamber so that the

  burner can operate without being subjected to counter

  significant pressure. As only part of the

  The filter element is not subjected to the regeneration operation each time, small burners can be used. Even if the heat input of the burner to the filter element is via a heat exchanger, the means used are smaller than in the case of

fixed filters.

  Instead of a gas or oil burner, it is also possible to use a heating bar

  which, in order to provide its power optimally,

  heater is placed at the focus of a concave mirror

of parabolic form.

  A regeneration facility

  electrically is preferably composed of an ionizing electrode of the particles contained in the exhaust gas and of a separation electrode which takes the ionized particles by slowly rotating and discharges them into a collector via a mechanical squeegee; these particles can be introduced again into the internal combustion engine. Thanks to the rotating filter element, it is also possible to suck the particles on the filter element. A nozzle used for this purpose can be connected to the combustion air intake system of the engine. It is also possible to clean the particle-loaded filter element with compressed air nozzles. In the case of a rotating band-shaped filter element, it is possible to provide a regeneration plant at one of the

return rollers.

  The present invention will be described in more detail with the aid of various examples of

  embodiment shown in the accompanying drawings, in the

  which: - Figures 1, 2 and 3 represent respectively a longitudinal section, a view from above

  and a cross-section of a first example of

and,

  FIGS. 4 to 6 represent

  respectively another embodiment.

  Figures 1 to 3 show a housing

  filter comprising three chambers of different volumes.

  A main box 10 which is provided with the inlet flange

  11 for the exhaust gas flow 12 surrounds a pre-

  first chamber 13. This chamber 13 houses a second housing 14 provided with passages 15 forming a second chamber 16. The second chamber 16 is connected to a third chamber 23 of an exhaust gas manifold 24 via a resonant element 20 and a throttling point 21; the manifold which receives the exhaust gases 25, cleaned,

leads to the atmosphere.

  The filter box thus produced

  at the same time a series or damped resonator

  noise. The chambers 13, 16 and 23 are designed so that their volume decreases in the direction of the flow of the exhaust gas. The volume of rooms 13, 16 and 23

  can for example correspond to ratios 1.6 / 1.2 / 1.0.

  The casing 14 of the second chamber 16 is housed inside the first chamber 13 so that a filter element 32 in the form of an endless band can rotate around the second casing 14 by passing on return rollers 30, 31 The filter element 32 may be constituted by a thin and flexible net sintered on a

  metal fiber fabric 34 refractory. The filament element

  trant 32 is moved in the direction of the arrow 37 by driving one of the deflection rollers 31. According to Figure 1, the drive means is constituted by a pendulum with a mass 38 which, in combination with a ratchet mechanism not shown in detail moves the

  return roller 31 and thus the filter element 32.

The pendulum training means

  suitable for a filter system applied to vehicles.

  When the plane of the pendulum corresponds to the longitudinal axis

  of the vehicle, the pendulum's weight makes movements

  pendulum during acceleration and braking

  of the vehicle under the effect of inertia. The mechanism with

  quet thus allows the pendulum, according to the application of the system, to trigger an advance movement of the return roller 31 or the filter element 32 only for

  acceleration or only for braking the vehicle.

  Thus in the case of a pendulum drive means,

  the filter element 32 is moved intermittently.

  However, it is possible to use any medium - entrnnihement. According to Figure 2,

  the drive means is constituted by an electric motor

  39 which allows to advance the filter element

  32 in a controlled, intermittent or continuous manner.

  Instead of a filter element made in the form of a strip, it is also possible to envisage any other embodiment such as for example a

rotating tube or the like.

  Independently of the embodiment of the filter element, this mobility has the decisive advantage that the regeneration process does not apply to the entire volume or the entire surface of the filter element. Much more according to the realization, one can use small sides or similar to predict

  a space-saving regeneration

summant can of energy.

  According to Figure 1, the reference point on the return roller 30 is provided for the regeneration of the filter. At this end, the main housing 10 is provided with an insulating layer 41 which at the same time delimits a regeneration chamber 42 inside the main housing 10. A burner 43 is provided for the regeneration;

  this burner supplies hot gases 44 to the regeneration chamber

  ration 42 thus separated and these hot gases arrive through an opening 45 in the exhaust gas manifold 24 in which the atmospheric pressure prevails. Thus, the regeneration chamber 42 is not influenced by the opposing pressure of the first chamber, so that the burner 43 can operate even while operating

the internal combustion engine.

  Other regeneration methods may apply to the principles described above and

  to be realized with reduced technical means.

  FIG. 4 shows an electrostatic regeneration according to which the particles retained by the filter element 32 are ionized using

  of an electrode 50 and are taken by the separating electrode

  ration 51 which turns slowly. A squeegee 52 scrapes the

  particles 53 of the electrode 51, which particles are

  picked in a collection container 54.

  According to FIG. 5, another example comprises an electric heating bar 60 which is arranged

  parallel to the deflection electrode 30 and which, for

  optimize the use of its heating power,

  is placed at the focus of a concave mirror 61 of parabo-

lic.

  Finally, FIG. 6 shows an embodiment comprising a suction-65 system that can for example be connected to the combustion air suction system.

of the internal combustion engine.

  The invention as described above

  above has the very important advantage that the regeneration chamber 42 can be made with the smallest possible volume in the case of the regeneration process

  according to FIGS. 1 and 5, which minimizes the

  the heat input to heat the corresponding masses

  at the ignition temperature of the particles or

soot.

  The exhaust gas stream 12 passes through the flange 11 to arrive in the first chamber 13 of the main casing 10. The exhaust gas cleaned having

  through the filter element 32 and the passages 16 of the bot-

  tier 14 arrives in the second chamber 16; the exhaust gas

  25, cleaned can pass from this chamber 16 either through one or more throttling points 21 and / or by a resonant element 20 in the exhaust manifold 24 to escape to the atmosphere. Meanwhile, the filter element 32 is moved continuously or intermittently in the direction of the arrow 37 and the area of the filter element 32 which in each case reaches the deflection zone 40 is then cleaned in a controlled manner. electrostatic, mechanical or combustion. Thanks to

  expansion chambers 13, 16, 23 and at the choke points

  intermediaries, we arrive at the same time with a

  Efficient sound waves of the exhaust gas

12.

  The regeneration plant is advantageously controlled intermittently in rhythm with the advance movement of the filter. It is

  It is also possible to envisage a regeneration plant

  continuous operation, for example for a

be running continuously.

R E V E ND I C A T IO NS

  1) Filter for separating solid particles contained in the exhaust gas of a Diesel engine, filter composed of a filter element which retains the particles contained in the gas vein which crosses

  this filter element, this element being housed in a bowl

  filter characterized in that the filter element (32)

  is mounted movably in the casing (10).

  2) Filter according to claim 1,

  characterized in that the filter element is a rotational tube

  tif. 3) Filter according to claim 2, characterized in that the filter element is ceramic

  porous or ceramic fiber or metal fiber.

  4) Filter according to claim 1, characterized in that the filter element (32) is produced

  in the form of a rotating endless band.

 ) Filter according to claim 4,

  characterized in that the filter element (32) is

killed by a metal fleece (34).

  6) Filter according to claim 5, characterized in that the metal fleece (34) is sintered

  on an endless band (33) refractory.

  7) Filter according to any one of

  Claims 1 to 6, characterized in that the casing of

  filter is constituted by a noise absorber with several

  chambers, the filter element (32) surrounding at least

a room (16).

  8) Filter according to any one of

  1 to 7, characterized by a drive means

  electrical connection (39) for the filter element.

  9) Filter for vehicles,

  according to any of claims 1 to 7, characterized

  rised by a ratchet mechanism and pendulum (38) for

  driving the filter element (32) and which is

  1.1 driven by acceleration or braking motion of the vehicle,) Filter according to any of the

  Claims 1 to 9, characterized in that the element

  filter (32) comprises a heat regeneration plant

  (43, 60). 11) Filter according to any one of

  Claims 7 and 10, characterized in that the chamber

  (42) of the regeneration plant (43) communicates with a chamber of the filter housing, and is provided downstream of the filter element (32) in the flow direction of the

exhaust gas.

  12) Filter according to any one of

  claims 1 to 9, characterized by an installation of

  electrostatic regeneration (50, 51, 52).

  13) Filter according to any one of

  Claims 1 to 9, characterized in that the installation

  regeneration device is constituted by a suction device (65). 14) Filter according to any one of

  Claims 1 to 9, characterized in that the installation

  regeneration consists of one or more nozzles

of compressed air.