Patent Publication Number: US-2019170034-A1

Title: Compact device for purification and recirculation of exhaust gas

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to FR 17 61588, filed 4 Dec. 2017. 
     FIELD OF INVENTION 
     The present invention relates to an exhaust gas purification and recirculation device, in particular for a motor vehicle exhaust system. 
     BACKGROUND OF THE INVENTION 
     An exhaust gas purification and recirculation device is in particular intended to reduce fuel consumption in a heat engine, particularly for a motor vehicle. 
     Such a purification and recirculation device known in the state of the art, in particular according to FR 3,041,033 A1, is relatively cumbersome, such that its integration into an exhaust line can be difficult to implement. 
     SUMMARY OF THE INVENTION 
     The invention in particular aims to resolve this drawback, by providing a compact device for the purification and recirculation of exhaust gas. 
     To that end, the invention in particular relates to an exhaust gas purification and recirculation device, in particular for a motor vehicle exhaust system, including: 
     an upstream pipe, extending along a first direction X 1 , and in which at least one exhaust gas purification member is housed; 
     a first downstream pipe, extending along a second direction X 2 , and in which at least one heat exchanger is housed; 
     a second downstream pipe configured to be connected to an exhaust gas outlet tube, and 
     an intermediate chamber that comprises: 
     an exhaust gas inlet communicating with the upstream pipe, downstream from the at least one exhaust gas purification member, 
     a first exhaust gas outlet communicating with the first downstream pipe, and 
     a second exhaust gas outlet communicating with the second downstream pipe, 
     and wherein the first direction X 1  and the second direction X 2  form an angle   between them comprised between 0° and 90°. 
     Thus, the upstream pipe and the first downstream pipe extend on a same side of the intermediate chamber, such that the gas purification and recirculation device according to the invention is more compact than a device according to the state of the art, in particular that according to FR 3,041,033 A1. 
     A device according to the invention may further include one or more of the following features, considered alone or according to any technically possible combinations: 
     the angle   formed between the first direction X 1  and the second direction is comprised between 0 and 45°, preferably between 0 and 30°, more preferably substantially equal to 0° and still more preferably equal to 0°. 
     the angle   formed between the first direction X 1  and the second direction X 2  is comprised between 45° and 90°. 
     the intermediate chamber is delimited by a shell formed by an assembly of at least two shell parts attached on one another. 
     the shell includes a first shell part comprising the exhaust gas inlet and the first exhaust gas outlet, and a second shell part comprising the second exhaust gas outlet. 
     the first exhaust gas outlet is covered by a filter. 
     the intermediate chamber includes exhaust gas guide elements arranged to guide a portion of the exhaust gas exiting the exhaust gas inlet toward the first exhaust gas outlet. 
     the intermediate chamber is at least partly delimited by a shell, the shell comprising a concave side converging toward the second exhaust gas outlet. 
     a bypass pipe parallel to the first downstream pipe, the bypass pipe being able to be closed by a dedicated valve. 
     the exhaust gas inlet is arranged across from the second exhaust gas outlet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood upon reading the following description, provided solely as an example and done in reference to the appended figures, in which: 
         FIG. 1  is an axial sectional schematic view of a purification and recirculation device according to one example embodiment of the invention; 
         FIG. 2  is a perspective view of the purification and recirculation device of  FIG. 1 ; 
         FIG. 3  is a top view of a first shell part delimiting an intermediate chamber of the device of  FIG. 1 ; and 
         FIG. 4  is a schematic top view of a second shell part delimiting the intermediate chamber of the device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  show an exhaust gas purification and recirculation device  10 , intended to be arranged in an exhaust system, in particular of a motor vehicle. 
     The purification and recirculation device  10  includes an upstream pipe  12 , extending along a first direction X 1 . This upstream pipe  12  is, for example, intended to be connected at the outlet of a turbocompressor of the exhaust system, traditionally for a turbocompressed engine or at the outlet of an exhaust manifold for an atmospheric engine. The upstream pipe  12  is, for example, made from stainless steel. 
     The upstream pipe  12  houses at least one exhaust gas purification member  14 , for example two purification members  14  in series. 
     Thus, the upstream pipe  12  performs a purification function of the purification and recirculation device  10 . 
     The purification and recirculation device  10  further includes a first downstream pipe  16 , extending along a second direction X 2 , and in which at least one traditional heat exchanger  18  is housed. The first downstream pipe  16  is, for example, made from stainless steel. 
     This first downstream pipe  16  is, for example, intended to be connected at the inlet of the turbocompressor for a turbocompressed engine, or downstream from a butterfly housing for an atmospheric engine, to perform a recirculation function of the purification and recirculation device  10 . The heat exchanger  18  is intended, as is known in itself, to decrease the temperature of the exhaust gases below a predefined maximum temperature, generally 160° C., before reinjecting the exhaust gases at the inlet of the turbocompressor or downstream from the butterfly housing. 
     The first downstream pipe  16  emerges in a downstream hose  19 , arranged downstream from the heat exchanger  18 . This downstream hose  19  includes a main valve  20 , movable between a closing position in which the exhaust gas cannot circulate in the first downstream pipe  16 , and a released position in which the exhaust gas can circulate freely in the first downstream pipe  16 . 
     As shown in  FIG. 2 , the purification and recirculation device  10  optionally includes a bypass pipe  22  substantially parallel, and preferably parallel, to the first downstream pipe  16 , also emerging in the downstream hose  19 . The exhaust gas circulation in the bypass pipe  22  is therefore conditioned by the position of the main valve  20 . 
     The bypass pipe  22  can further be closed by a dedicated valve  24  of the traditional type. This bypass pipe  22  is intended, as is known in itself, to keep the temperature high enough (for example above 65° C.) and to prevent the formation of condensation in the heat exchanger  18 . The dedicated valve  24  is opened or closed based on the temperature of the exhaust gas. 
     The purification and recirculation device  10  further includes a second downstream pipe  28 , intended to be connected to an exhaust gas outlet tube. The second downstream pipe  28  is, for example, made from stainless steel. 
     The purification and recirculation device  10  includes an intermediate chamber  30  comprising: 
     an exhaust gas inlet  32  communicating with the upstream pipe  12 , downstream from the purification member  14 , and for example directly downstream from the purification member  14 , 
     a first exhaust gas outlet  34  communicating with the first downstream pipe  16 , and 
     a second exhaust gas outlet  36  communicating with the second downstream pipe  28 . 
     It should be noted that the first exhaust gas outlet  34  is advantageously covered by a filter  37 . This filter  37  is, for example, formed by a metal net. This filter  37  is intended to prevent the passage of particles, in particular ceramic particles from the purification member(s)  14 , toward the turbocompressor for a turbocompressed engine or downstream from the butterfly housing for an atmospheric engine. 
     According to the invention, the first direction X 1  and the second direction X 2  form an angle   between them comprised between 0° and 90°, inclusive. 
     It should be noted that in the state of the art, the first and second directions are generally aligned, and therefore form an angle of 180°. 
     An angle of 0° in fact corresponds to parallel first X 1  and second X 2  directions, as is the case in the example shown in  FIG. 1 . In this case, the upstream pipe  12  and the first downstream pipe  16  extend parallelly, next to one another. 
     Preferably, the angle   formed between the first direction X 1  and the second direction X 2  is comprised between 0 and 45°. 
     Advantageously, the angle   formed between the first direction X 1  and the second direction X 2  is comprised between 0 and 30°. 
     More preferably, the angle   is substantially equal to 0° and still more preferably equal to 0°. 
     Alternatively, the angle   formed [between] the first direction and the second direction is comprised between 45° and 90°. 
     According to one preferred embodiment, the intermediate chamber  30  is at least partially delimited by a shell formed by an assembly of at least two shell parts  30   a ,  30   b  attached on one another. 
     For example, the shell includes: 
     a first shell part  30   a  comprising the exhaust gas inlet  32 , and the first exhaust gas outlet  34 , and 
     a second shell part  30   b  comprising the second exhaust gas outlet  36 . 
     Alternatively, the intermediate chamber  30  could be formed by a plurality of shell parts. 
     The first shell part  30   a  is shown schematically in  FIG. 2 , in a bottom view, i.e., from an inside of the intermediate chamber  30 . 
     This first shell part  30   a  is, for example, substantially planar, but may alternatively have any possible shape. As shown in  FIG. 2 , the exhaust gas inlet  32  and the first exhaust gas outlet  34  are arranged in this first shell part  30   a . Another opening  38 , intended to be connected to the bypass pipe  22 , is also arranged in the first shell part  30   a , near the first exhaust gas outlet  34 . 
     The second shell part  30   b  is shown schematically in  FIG. 3 , in a top view, i.e., from the inside of the intermediate chamber  30 . 
     The second shell part  30   b  preferably has a generally concave shape converging toward the second exhaust gas outlet  36 . This concave side is more particularly visible in  FIG. 2 . Because of this concavity, the exhaust gas in the intermediate chamber  30  is easily guided toward the second exhaust gas outlet  36 , in particular when the main valve  20  is in the closing position. In other words, when the main valve  20  is in the closing position, the presence of the first downstream pipe  16  does not hinder the flow of the gas stream toward the second downstream pipe  28 , the exhaust gas stream being naturally guided by the concavity toward the second exhaust gas outlet  36 . 
     It should also be noted that the second exhaust gas outlet  36  is preferably arranged across from the exhaust gas inlet  32 . This is also preferably the case in other embodiments not limited to two shell parts. 
     Furthermore, according to the described embodiment, the second shell part  30   b  bears exhaust gas guiding elements  40 . 
     Alternatively, the exhaust gas guiding elements  40  could be arranged differently in the intermediate chamber  30 . 
     The exhaust gas guide elements  40  are arranged to guide a part of the exhaust gas coming from the inlet toward the first exhaust gas outlet  34 . Thus, they are arranged on the second shell part  30   b , at least in part substantially across from the first exhaust gas outlet  34 . Thus, the gas coming from the upstream pipe  12 , arriving on the zone of the second shell part  30   b  comprising the exhaust gas guiding elements  40 , will be guided by these exhaust gas guiding elements  40  toward the first exhaust gas outlet  34 . 
     Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content of this disclosure.