Patent Publication Number: US-2023142603-A1

Title: Filter detection in a system for capturing braking particles

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is the U.S. national phase of International Application No. PCT/EP2021/054609 filed Feb. 24, 2021, which designated the U.S. and claims priority to FR 2002020 filed Feb. 28, 2020, the entire contents of each of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to a system for capturing the braking particles from a friction brake system, which comprises a vacuum source, a pneumatic circuit which connects the friction brake system to the vacuum source, and a filter located on the pneumatic circuit and mounted on a support. 
     Description of the Related Art 
     Such friction brake systems may equip road or rail vehicles. Such friction brake systems may also equip stationary rotor machines such as wind turbines or industrial machines. 
     In such systems, there is provided a vacuum source (for example a suction turbine driven by a motor) which is connected by a pneumatic circuit to the friction brake system, and a filter for collecting particles emitted by the braking system. This filter is placed upstream of the vacuum source, and prevents the passage of particles through the vacuum source and their release into the atmosphere. However, in certain situations, this filter may be missing, for example because it was not replaced during a vehicle service. Absence of the filter is detrimental, because the particles will then pass into the vacuum source and be released into the atmosphere. The filtering function is then no longer ensured. 
     SUMMARY OF THE INVENTION 
     This invention aims to remedy these disadvantages. 
     The invention aims to propose a system for capturing braking particles which makes it possible to inform the user of the vehicle of the absence of the capturing system filter, so that the user can act accordingly, and in particular can place a filter in the system. 
     This object is achieved due to the fact that the capturing system comprises a control unit and a filter detection device which is capable of sending at least one signal to the control unit, the control unit being capable, on the basis of this signal, of identifying the absence of the filter on the pneumatic circuit and of informing a user of this absence of the filter. 
     Due to these arrangements, an absence of the filter on the pneumatic circuit is detected and determined, and the user is immediately informed via the control unit. One will note that the control unit is capable of identifying both an absence of the filter on its support, and an absence of the support (with its filter) on the pipe. Indeed, in some cases it is more practical to change the assembly composed of the support and filter. The user can then act accordingly, and place a filter on its support or place a support (with its filter) on the pipe, in order to prevent the release of harmful particles into the atmosphere. 
     Advantageously, the detection device comprises a pressure sensor which is located on the pneumatic circuit upstream of the filter, the pressure sensor being capable of sending in a signal to the control unit a measurement of the pressure P 1  in the pneumatic circuit upstream of the filter, the control unit, upon receiving this signal, being capable of comparing the measured pressure P 1  with a reference pressure PR which is the pressure in the pneumatic circuit in the absence of a filter for the reference operating state ER of the vacuum source during the measurement of pressure P 1  by the pressure sensor, the control unit being capable of informing a user of the absence of the filter on the pneumatic circuit when the measured pressure P 1  is substantially equal to the reference pressure PR or is substantially equal to the atmospheric pressure. 
     Thus, in the case where the circuit or the filter support already includes a pressure sensor, it is not necessary to install an additional detection device. 
     Advantageously, the detection device comprises a first pressure sensor which is located on the pneumatic circuit upstream of the filter, the pressure sensor being capable of sending in a signal to the control unit a measurement of the first pressure P 1  in the pneumatic circuit upstream of the filter, and a second pressure sensor which is located on the pneumatic circuit downstream of the filter and which is capable of sending in a signal to the control unit a measurement of the second pressure P 2  in the pneumatic circuit downstream of the filter, the control unit, upon receiving this at least one signal, being capable of comparing the first measured pressure P 1  and the second measured pressure P 2 , the control unit being capable of informing a user of the absence of the filter on the pneumatic circuit when the first measured pressure P 1  and the second measured pressure P 2  are substantially equal or when the first measured pressure P 1  is substantially equal to the atmospheric pressure. 
     Thus, in the case where the circuit or the filter support already includes two pressure sensors, it is not necessary to install an additional detection device. 
     Advantageously, the detection device comprises a contact detector which is capable of detecting contact between the filter and the support, the contact detector being capable of sending a signal to the control unit when there is no contact between the filter and the support, the control unit, upon receiving the signal, being capable of informing a user of the absence of the filter. 
     The reliability of the filter detection is thus improved. 
     Advantageously, the detection device comprises a contact detector which is capable of detecting contact between the support and the circuit, the contact detector being capable of sending a signal to the control unit when there is no contact between the support and the circuit, the control unit, upon receiving the signal, being capable of informing a user of the absence of the filter. 
     The reliability of the filter detection is thus improved. 
     Advantageously, the detection device comprises an identifier which is carried by the filter or by the support and a contactless detector which is fixed close to the support and which is capable of detecting the presence of the identifier, the contactless detector being capable of sending a signal to the control unit when the identifier is not detected by the contactless detector, the control unit, upon receiving the signal, being capable of informing a user of the absence of the filter. 
     Thus, it is not necessary to establish an extremely precise positioning of the filter on its support: it is sufficient that the filter is mounted on the support. 
     For example, the identifier is carried by the support and the contactless detector is fixed to the pipe. 
     For example, the identifier is carried by the filter and the contactless detector is fixed to the support. 
     The invention also relates to a method for detecting the absence of a filter in a system for capturing braking particles from a friction brake system, this capturing system comprising a vacuum source, a pneumatic circuit which connects the friction brake system to the vacuum source, and a filter located on the pneumatic circuit and mounted on a support. 
     According to the invention, the method comprises the following steps 
     (a) A control unit and a filter detection device are provided, which form part of the capturing system;
 
(b) The detection device sends at least one signal to the control unit;
 
(c) On the basis of this signal, the control unit identifies the absence of the filter on the pneumatic circuit and informs a user of this absence of the filter.
 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood and its advantages will be more apparent, upon reading the following detailed description of embodiments shown as non-limiting examples. The description refers to the accompanying drawings, in which: 
         FIG.  1    is a schematic view of a capturing system according to the invention, 
         FIG.  2    is a perspective view of a housing carrying a filter, and of a device for detecting this filter in the capturing system of  FIG.  1   , 
         FIG.  3    is a perspective view of a housing carrying a filter, and of a variant of the embodiment of a device for detecting this filter in the capturing system of  FIG.  2   , 
         FIG.  4    is a perspective view of a housing carrying a filter, and of a second embodiment of a device for detecting this filter in the capturing system of  FIG.  1   , 
         FIG.  5    is a perspective view of a housing carrying a filter, and of a variant of the second embodiment of a device for detecting this filter in the capturing system of  FIG.  1   , 
         FIG.  6    is a perspective view of a housing carrying a filter, and of a third embodiment of a device for detecting this filter in the capturing system of  FIG.  1   , 
         FIG.  7    is a perspective view of a housing carrying a filter, and of a variant of the third embodiment of a device for detecting this filter in the capturing system of  FIG.  1   . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG.  1    schematically represents a particle capturing system  1  according to the invention, these particles being emitted by a friction brake system  10 . 
     This friction brake system  10  comprises a brake pad  11  for braking a vehicle. This pad  11  comprises a backing plate  12  and a lining  13  made of friction material fixed to the backing plate  12 . In  FIG.  1   , the pad  11  is viewed from below, the plate  12  being in the foreground. 
     The pad  11  (first pad) is facing a disc  9  which is driven by the wheel of the vehicle. A second identical pad (not visible) is located on the other side of the disc  9  and opposite the first pad  11  so that these two pads sandwich the disc  9 . Braking of the disc  9  is achieved by friction of the two linings ( 13 ) against the disc  9  when these two pads approach the disc  9 . 
     The capturing system  1  comprises a pneumatic circuit  30  and a vacuum source  20 . The pad  11  and the second pad are connected to the vacuum source  20  via this pneumatic circuit  30 . For example, the vacuum source  20  comprises an electric motor  21  and a suction turbine  22  which is driven by this electric motor  21 . 
     During operation, the vacuum source  20  is capable of suctioning in the particles upon their emission by the linings ( 13 ), through the pneumatic circuit  30 . The direction of circulation of the air and particles during normal operation is indicated by the arrow F in  FIG.  1   . The arrow F therefore indicates a flow from upstream to downstream. The capturing system  1  further comprises a filter  40  which is located on the circuit  30 , meaning that it is traversed by the air which circulates in the circuit  30 . This filter  40  is mounted on a support  41  which is fixed to the pipe  30 . For example, the support  41  is a housing which houses the filter  40  therein, as shown in the figures. The filter  40  thus separates the housing  41  into an upstream portion and a downstream portion. The air coming from the upstream portion of the circuit  30  enters the housing  41  at the upstream end of the housing  41 , passes through the filter  40 , and exits the housing  41  at the downstream end of the housing  41  to enter the downstream portion of the circuit  30 . 
     The capturing system  1  further comprises a control unit  60  and a detection device  50  for detecting the filter  40 . This control unit  60  and this detection device  50  are used to identify an absence of the filter  40  on its support  41 , or an absence of the support  41  on the pipe  30  (and consequently an absence of the filter  40 ). The control unit  60  receives signals from the detection device  50  (which comprises an element for generating and sending these signals), and is also capable of controlling the vacuum source  20  and receiving information therefrom. These interactions between the control unit  60 , the detection device  50 , and the vacuum source  20  are schematically represented in  FIG.  1    by solid lines. These interactions may be implemented by electric lines. The operation of this control unit  60  and of this detection device  50  is described below. 
     During operation of the capturing system  1 , the detection device  50  sends at least one signal to the control unit  60 . “At least one signal” is understood to mean the sending of a continuous signal, or a signal at regular intervals, or an isolated signal when an absence of the filter  40  on its support  41  is initially detected. The control unit  60  identifies the absence of the filter  40  on the basis of this signal, then informs a user of the absence of the filter  40 . This information may be provided by any means, for example by displaying text such as “Filter missing” or a logo or an indicator light on the vehicle&#39;s dashboard, and/or for example by stimulation of the user by vibrations via a vibratory system located in the seat and controlled by the control unit  60 . 
     In addition, this information may be accompanied by a limitation of the speed of the vehicle, using a limiter  70  which is controlled by the control unit  60  ( FIG.  1   ). The generation of particles during braking is consequently reduced, and the release of these harmful particles into the vacuum source  20  is also reduced. 
     A first embodiment of the detection device  50  for detecting the filter  40  is described below, with reference to  FIG.  2   .  FIG.  2    is a more detailed view of the support  41 , the filter  40 , and the detection device  50 . 
     The detection device  50  comprises a (first) pressure sensor  51  which is located on the pneumatic circuit  30 , upstream of the filter  40 . Ideally, the pressure sensor  51  is located sufficiently close to the filter  40  so that the pressure measured by the pressure sensor  51  is identical to the pressure where the filter  40  is, or where it would be if it were present. Thus, the pressure sensor  51  is located either on the pneumatic circuit  30  close to the support  41  of the filter  40  (which makes it possible to identify an absence of the support  41 ), or in the support  41  for the filter  40  as represented in  FIG.  2   . “Located in the support  41 ” is understood to mean that the pressure sensor is located on the support, or in the support if this support is a housing, and in all cases this sensor measures the pressure at the location of this support  41 . 
     The pressure sensor  51  is capable of measuring the (first) pressure P 1  in the pneumatic circuit  30  upstream of the filter  40 , and the detection device  50  is capable of sending this measurement in a signal to the control unit  60 . During this measurement, the vacuum source  20  operates according to an operating state called the reference operating state ER. This operating state is characterized by a parameter which is for example the speed of rotation V of the suction turbine  22 . Thus, in the reference operating state ER, the suction turbine  22  rotates at a speed of rotation VR. The control unit  60  has a reference pressure PR in memory, which is the pressure generated in the pneumatic circuit  30  in the absence of a filter  40  for the reference operating state ER of the vacuum source  20 . It is understood that this reference pressure PR varies as a function of this reference operating state ER. Thus, the reference pressure PR varies as a function of the speed of rotation VR of the turbine  22 . The control unit  60 , upon receiving the signal comprising the pressure P 1  measured in the pneumatic circuit  30 , compares this measured pressure P 1  with the reference pressure PR. This reference pressure PR corresponds to the pressure in the pneumatic circuit  30  in the absence of a filter  40  for the reference operating state ER of the vacuum source  20 , and the measurement of the first pressure P 1  by the pressure sensor  51  is performed during this reference operating state ER. Consequently, if the first pressure P 1  is substantially equal to the reference pressure PR, this means that the filter  40  is absent from its support  41  (or that the filter  40  is torn), or that the support  41  (and therefore the filter  40 ) is absent although the upstream portion of the circuit  30  and the downstream portion of the circuit  30  are connected to the place where the support  41  should be located. Indeed, one will note that if the filter  40  is present, then the pressure upstream of the filter  40  is higher than the reference pressure PR because the filter  40 , even when not clogged, contributes to preventing the passage of air. Thus, in the situation where P 1  is substantially equal to PR, the control unit  60  informs the user of the absence of the filter  40 . “Substantially equal” is understood to mean that the pressure is within a restricted interval around the reference pressure. For example, this interval is +/−1%, or +/−2%, or +/−5%, or +/−10% of the reference pressure value. 
     In the particular situation where, for the reference operating state ER, the support  41  is absent and the upstream portion of the circuit  30  and the downstream portion of the circuit  30  are not connected, then the measured pressure P 1  is substantially equal to the atmospheric pressure. Also in this case, the control unit  60  informs the user of the absence of the filter  40 . 
     A variant of the first embodiment is described below, in which the detection device  50  comprises a second pressure sensor  52  in addition to the first pressure sensor  51 . This variant is illustrated in  FIG.  3   . The first pressure sensor  51  is located upstream of the filter  40 , on the circuit  30 . The second pressure sensor  52  is located downstream of the filter  40 , on the circuit  30 . The configuration where the first sensor  51  is located upstream of the support  41  and where the second sensor  52  is located downstream of the support  41  makes it possible to identify an absence of the support  41 . For example, the first sensor  51  and the second sensor  52  are located in the support  41 , as illustrated in  FIG.  3   . The first pressure sensor  51  is capable of measuring a first pressure P 1  in the pneumatic circuit  30  upstream of the filter  40 , and the detection device  50  is capable of sending this measurement in a signal to the control unit  60 . In parallel, for example simultaneously, the second pressure sensor  52  is capable of measuring a second pressure P 2  in the pneumatic circuit  30  downstream of the filter  40 , and the detection device  50  is capable of sending this measurement in a signal to the control unit  60 . For example, the measurement of the first pressure P 1  and the measurement of the second pressure P 2  are sent in the same signal. The control unit  60 , upon receiving this or these signals, is capable of comparing the first pressure P 1  with the second pressure P 2 . If the first pressure P 1  is substantially equal to the second pressure P 2 , this means that the filter  40  is absent from its support  41  (or that the filter  40  is torn), or that the support  41  (and therefore the filter  40 ) is absent although the upstream portion of the circuit  30  and the downstream portion of the circuit  30  are connected to the place where the support  41  should be located. Indeed, one will note that if the filter  40  is present, then the pressure upstream of the filter  40  is greater than the pressure downstream of the filter  40 . Thus, in the situation where P 1  is substantially equal to P 2 , the control unit  60  informs the user of the absence of the filter  40 . 
     In the particular situation where, during operation of the capturing system, the support  41  is absent and where the upstream portion of the circuit  30  and the downstream portion of the circuit  30  are not connected, then the measured pressure P 1  is substantially equal to the atmospheric pressure. Also in this case, the control unit  60  informs the user of the absence of the filter  40 . 
     A second embodiment of the detection device  50  for detecting the filter  40  is described below, with reference to  FIGS.  4  and  5   . 
     The detection device  50  comprises a contact detector  53 . In a first variant illustrated in  FIG.  4   , this contact detector  53  is mounted on the support  41  such that when the filter  40  is placed in (or on) the support  41 , the filter  40  is in physical contact with the contact detector  53 . This physical contact is achieved for example by the filter  40  touching an element that is part of the contact detector  53 . For example this element is a retractable contactor with return (spring-loaded), for which the retraction movement generates a signal. Alternatively, this physical contact is achieved for example by cooperation between a male element mounted on the contact detector  53  (respectively on the filter  40 ) and a female element mounted on the filter  40  (respectively on the contact detector  53 ). The contact detector  53  is thus capable of detecting contact between the filter  40  and the support  41 , and therefore the presence of the filter  40  in (or on) the support  41 . When there is no contact between the filter  40  and the support  41 , meaning that the filter  40  is absent from the support  41 , the detection device  50  sends a signal to the control unit  60 . For example, this signal is sent at regular intervals as long as the filter  40  is absent from the support  41 . The control unit  60 , upon receiving this signal, informs a user of the absence of the filter  40 . 
     In a second variant illustrated in  FIG.  5   , the contact detector  53  is mounted on the circuit  30 , upstream or downstream of the support  41 , such that when the support  41  is placed on the circuit  30 , the support  41  is in physical contact with the contact detector  53 . This physical contact is achieved for example by the support  41  touching an element that is part of the contact detector  53 . Alternatively, this physical contact is achieved for example by engagement between a male element mounted on the contact detector  53  (respectively on the support  41 ) and a female element mounted on the support  41  (respectively on the contact detector  53 ). When there is no contact between the support  41  and the pipe  30 , meaning that the support  41  is not mounted on the pipe  30  (and therefore the filter  40  is absent), the detection device  50  sends a signal to the control unit  60 . For example, this signal is sent at regular intervals as long as the support  41  is absent from the pipe  30 . The control unit  60 , upon receiving this signal, informs a user of the absence of the filter  40 . 
     A third embodiment of the detection device  50  for detecting the filter  40  is described below, with reference to  FIGS.  6  and  7   . 
     The detection device  50  comprises a contactless detector  54  and an identifier (tag)  42  which is carried by the filter  40  or by the support  41 . The contactless detector  54  is capable of detecting the presence of the identifier  42  within a certain volume VO around this detector  54 . This detection is carried out for example with RFID technology. RFID technology groups those technologies where the identifier is powered remotely by the detector. The contactless detector  54  is fixed close to the support  41 , meaning that the identifier  42  (whether carried by the filter  40  or by the support  41 ) is located within the volume VO around the contactless detector  54 . 
     In a first variant illustrated in  FIG.  6   , the contactless detector  54  is fixed to the pipe  30  upstream or downstream of the support  41 , and the identifier  42  is carried by the support  41 . Thus, the contactless detector  54  is located at a distance D 1  from the identifier  42  when the support  41  is mounted on the pipe  30 , and the contactless detector  54  is calibrated so that if the distance between itself and the identifier  42  is greater than the distance D 1 , meaning that if the support  41  (and therefore the filter  40 ) is absent from the pipe  30 , the identifier  42  is not detected. In this case, the detection device  50  sends a signal to the control unit  60 . For example, this signal is sent at regular intervals as long as the support  41  is absent from the pipe  30 . The control unit  60 , upon receiving this signal, informs a user of the absence of the filter  40 . In this variant, the identifier  42  could be carried by the filter  40  as long as the contactless detector  54  is located at distance D 1  from the identifier  42 . 
     In a second variant illustrated in  FIG.  7   , the contactless detector  54  is fixed on the support  41  (for example it is placed within the housing when the support  41  is a housing), and the identifier  42  is carried by the filter  40 , such that the contactless detector  54  is located at a distance D 2  from the identifier  42  when the filter  40  is mounted on the support  41 . The contactless detector  54  is calibrated so that if the distance between itself and the identifier  42  is greater than the distance D 2 , meaning that if the filter  40  is absent from the support  41 , the identifier  42  is not detected. In this case, the detection device  50  sends a signal to the control unit  60 . For example, this signal is sent at regular intervals as long as the filter  40  is absent from the support  41 . The control unit  60 , upon receiving this signal, informs a user of the absence of the filter  40 . 
     The various embodiments described above may be used alone, or in combinations of two or more. 
     In certain embodiments, in particular in the third embodiment described above with a male-female engagement between the filter  40  and the contact detector  53  mounted on the support  41 , the support  41  is for example capable of receiving only a certain type of filter  40  (those filters  40  whose male element (respectively female) is capable of engaging with the female element (respectively male) of the contact detector  53 . Thus, one can ensure that only a certain filter  40  (for example of a given quality or brand) is mounted on the support  41 . Similarly, in the case of a male-female engagement between the support  41  and the contact detector  53  mounted on the pipe  30 , the pipe  30  is for example only capable of receiving a certain type of support  41 . Thus, it can be ensured that only a certain support  41  carrying a certain filter  40  (for example of a given quality or brand) is mounted on the pipe  30 . 
     In the fourth embodiment, the identifier  42  may be identical for any filter  40  or support  41 , in which case this identifier  42  only serves to determine whether the filter  40  is present or absent on the circuit  30 . Alternatively, the identifier  42  may be distinct (via a code that it contains) for each filter  40  (or each support  41 ), or for each type of filter  40  (or each type of support  41 ). In the latter case, the contactless detector  54  may be configured to detect only identifiers  42  corresponding to a certain type of filter  40  (or support  41  carrying this type of filter  40 ), which makes it possible to ensure that only this type of filter  40  is mounted on the pipe  30 . 
     The invention also relates to a method for detecting the absence of a filter  40  in a system  1  for capturing braking particles from a friction brake system  10 . As described above, this capturing system  1  comprises a vacuum source  20 , a pneumatic circuit  30  which connects the friction brake system  10  to the vacuum source  20 , and a filter  40  which is located on the pneumatic circuit  30  and which is mounted on a support  41 . The method comprises the following steps: 
     (a) A control unit  60  and a detection device  50  for detecting said filter  40  are provided, which are part of the capturing system  1 ;
 
(b) The detection device  50  sends at least one signal to the control unit  60 ;
 
(c) On the basis of this signal, the control unit  60  identifies the absence of the filter  40  on the pneumatic circuit  30 , and informs a user of this absence of the filter  40 .