Abstract:
A housing has an outer pipe. An inner pipe is accommodated in the outer pipe. The inner pipe defines an inner passage internally. The inner pipe defines an annular passage externally with the outer pipe. The inner pipe has through holes communicating the inner passage with the annular passage. The housing internally defines an EGR channel communicating with the annular passage. The EGR channel accommodates a deflector partitioning the EGR channel.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to an EGR device having a deflector for an internal combustion engine of a vehicle. The present disclosure further relates to an EGR mixer for the EGR device. 
       BACKGROUND 
       [0002]    A vehicle may be equipped with an exhaust gas recirculation system (EGR system). The EGR system is to reduce emission contained in exhaust gas discharged from an internal combustion engine. The EGR system may recirculate a part of exhaust gas into fresh air to produce mixture gas containing recirculated exhaust gas and fresh air. Recirculated exhaust gas may be unevenly mixed with fresh air to reduce combustion efficiency of the engine consequently. 
       SUMMARY 
       [0003]    The present disclosure addresses the above-described concerns. 
         [0004]    According to an aspect of the preset disclosure, an EGR device comprises a housing having an outer pipe. The EGR device further comprises an inner pipe accommodated in the outer pipe. The inner pipe defines an inner passage internally. The inner pipe defines an annular passage externally with the outer pipe. The inner pipe has a plurality of through holes communicating the inner passage with the annular passage. The housing internally defines an EGR channel communicating with the annular passage. The EGR channel accommodates a deflector partitioning the EGR channel. 
         [0005]    According to another aspect of the preset disclosure, an EGR mixer is for an EGR device. The EGR mixer is configured to be accommodated in an outer pipe of a housing of the EGR device to define an annular passage with the outer pipe. The EGR mixer comprises a pipe body defining an inner passage and having a plurality of through holes arranged along a circumferential direction of the pipe body, the through holes communicating the inner passage with the annular passage. The EGR mixer further comprises a deflector accommodated in an EGR channel formed in the housing to partition the EGR channel at an upstream side of the pipe body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: 
           [0007]      FIG. 1  is a block diagram showing an EGR system for an internal combustion engine of a vehicle; 
           [0008]      FIG. 2  is a sectional view showing an EGR device for the EGR system, according to a first embodiment; 
           [0009]      FIG. 3  is a sectional view showing the EGR device, the sectional view corresponding to a section taken along the line III-III in  FIG. 2 ; 
           [0010]      FIG. 4  is a perspective sectional view showing the EGR device; 
           [0011]      FIGS. 5 to 7  are sectional views showing an EGR device according to second to fourth embodiments; 
           [0012]      FIGS. 8 to 9  are sectional views showing an EGR device according to fifth to sixth embodiments; and 
           [0013]      FIG. 10  is a sectional view showing an EGR device according to a seventh embodiment. 
       
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
       [0014]    In the following description, a radial direction is along an arrow represented by “RADIAL” in drawing(s). An axial direction is along an arrow represented by “AXIAL” in drawing(s). A circumferential direction is along an arrow represented by 
         [0015]    “CIRCUMFERENTIAL” in drawing(s). A vertical direction is along an arrow represented by “VERTICAL” in drawing(s). A horizontal direction is along an arrow represented by “HORIZONTAL” in drawing(s). A flow direction is along an arrow represented by “FLOW” in drawing(s). 
         [0016]    As follows, a first embodiment of the present disclosure will be described with reference to  FIGS. 1 to 4 . As shown  FIG. 1 , according to the present example, an internal combustion engine  150  has four cylinders connected with an intake manifold  148  and an exhaust manifold  152 . 
         [0017]    The engine  150  is combined with an intake and exhaust system. The intake and exhaust system includes an intake valve  110 , an intake passage  112 , an EGR device  10 , a mixture passage  122 , a turbocharger including a compressor  130  and a turbine  160 , a charge air passage  142 , and an intercooler  140 . The intake and exhaust system further includes a combustion gas passage  158 , an exhaust passage  162 , an EGR passage  172 , and an EGR cooler  180 . 
         [0018]    The intake passage  112  is equipped with the intake valve  110 . The intake passage  112  is connected with the EGR device  10 . The EGR device  10  is connected with the compressor  130  through the mixture passage  122 . The compressor  130  is connected with the intake manifold  148  through the charge air passage  142 . The charge air passage  142  is equipped with the intercooler  140 . The exhaust manifold  152  is connected with the turbine  160  through the combustion gas passage  158 . The turbine  160  is connected with the exhaust passage  162 . The EGR passage  172  is branched from the exhaust passage  162  and connected with the EGR device  10 . The EGR passage  172  is equipped with the EGR cooler  180 . 
         [0019]    The intake passage  112  conducts fresh air from the outside of the vehicle through the intake valve  110  into the EGR device  10 . The intake valve  110  regulates a quantity of fresh air flowing through the intake passage  112  into the EGR device  10 . The EGR device  10  draws fresh air from the intake passage  112  and draws exhaust gas from the exhaust passage  162  through the EGR passage  172 . The EGR device  10  includes an EGR mixer to blend the drawn fresh air with the drawn exhaust gas to produce mixture gas. The mixture passage  122  conducts the mixture gas from the EGR device  10  into the compressor  130 . 
         [0020]    The compressor  130  is rotatably connected with the turbine  160  via a common axis. The compressor  130  is driven by the turbine  160  to compress the mixture gas. The charge air passage  142  conducts the compressed mixture gas to the intake manifold  148 . The intercooler  140  is a heat exchanger to cool the compressed mixture gas conducted through the charge air passage  142 . 
         [0021]    The engine  150  draws the cooled mixture gas. The engine  150  forms air-fuel mixture with the drawn mixture gas and injected fuel in each cylinder and burns the air-fuel mixture in the cylinder to drive a piston in the cylinder. The engine  150  emits combustion gas (exhaust gas) through the exhaust manifold  152  into the combustion gas passage  158 . The combustion gas passage  158  conducts the combustion gas into the turbine  160 . The turbine  160  is driven by the exhaust gas to drive the compressor  130  thereby to cause the compressor  130  to compress mixture gas and to press-feed the compressed mixture gas through the charge air passage  142  and the intercooler  140  into the engine  150 . 
         [0022]    The exhaust passage  162  conducts exhaust gas (combustion gas) from the turbine  160  to the outside of the vehicle. The EGR passage  172  is branched from the exhaust passage  162  at the downstream side of the turbine  160  to recirculate a part of exhaust gas from the exhaust passage  162  into the EGR device  10 . The EGR cooler  180  is a heat exchanger to cool exhaust gas flowing though the EGR passage  172  into the EGR device  10 . The EGR device  10  is located at a connection among the intake passage  112 , the EGR passage  172 , and the mixture passage  122 . The EGR passage  172  is merged with the intake passage  112  in the EGR device  10 . The EGR device  10  includes an EGR valve  90  to regulate a quantity of EGR gas recirculated into the EGR mixer. 
         [0023]    As described above, the EGR system is configured to recirculate a part of exhaust gas from the exhaust passage  162  into the intake passage  112 . The circulated exhaust gas may contain oxygen at a lower percentage compared with oxygen contained in fresh air. Therefore, circulated exhaust gas may dilute mixture of exhaust gas and fresh air thereby to reduce peak temperature of combustion gas when burned in the combustion chamber of the engine  150 . In this way, the EGR system may reduce oxidization of nitrogen, which is caused under high temperature, thereby to reduce nitrogen oxide (NOx) occurring in the combustion chamber. 
         [0024]    Subsequently, the configuration of the EGR device  10  will be described in detail. As shown in  FIGS. 2 to 4 , the EGR device  10  includes a housing  20  accommodating an inner pipe (EGR mixer, pipe body)  50 , the EGR valve  90 , and a motor  94 . The housing  20 , the inner pipe  50 , and the EGR valve  90  are formed of a metallic material such as stainless steel and/or an aluminum alloy. 
         [0025]    The housing  20  includes an air inlet  22 , an outer pipe  40 , an outlet  26 , an EGR inlet  28 , and an EGR guide  32 . The air inlet  22  is connected with the intake passage  112 . The outlet  26  is connected with the mixture passage  122 . The outer pipe  40  is located between the air inlet  22  and the outlet  26 . The outer pipe  40  is greater than both the air inlet  22  and the outlet  26  in inner diameter to form an annular groove extending in the circumferential direction. 
         [0026]    The inner pipe  50  is in a tubular shape and is inserted in the housing  20 . The inner pipe  50  is affixed to the housing  20  by, for example, welding. The inner pipe  50  has an outer periphery, which defines an annular passage  48  with an inner periphery of the outer pipe  40 . The annular passage  48  extends in the circumferential direction. The inner pipe  50  has an inner periphery, which defines an inner passage  52  communicated with the intake passage  112  and the mixture passage  122 . The inner pipe  50  has an inner periphery defining a curvature to reduce the inner passage  52  at an intermediate portion  54  in the axial direction. The intermediate portion  54  forms a throttle radially inward. 
         [0027]    The inner pipe  50  has multiple through holes  56 , which are arranged along the circumferential direction. According to the present example, the inner pipe  50  has five through holes  56 , which are arranged substantially at angular intervals, such as 60-degree intervals. Each of the through holes  56  extends along the radial direction through an inner wall of the inner pipe  50 . The through hole  56  is directed substantially at 90 degrees relative to a center axis of the inner pipe  50 . 
         [0028]    The EGR inlet  28  is connected with the EGR passage  172 . The EGR inlet  28  is communicated with an EGR channel  46  defined in the EGR guide  32 . The EGR channel  46  is configured to be communicated with the annular passage  48 . 
         [0029]    The EGR valve  90  is, for example, a butterfly valve having a shaft, which is rotatably supported by bearings at both ends. Thus, the EGR valve  90  is rotatably equipped in the EGR guide  32  and is variable in rotational position to control an opening area of the EGR channel  46 . The EGR valve  90  is rotatable between a full close position and a full open position. The EGR valve  90  is at the full close position when being at the position represented by dotted line in  FIG. 3 . The motor  94  ( FIG. 2 ) is equipped to one end of the shaft to drive the EGR valve  90 . An electronic control unit (ECU)  98  is electrically connected with the motor  94  to control electricity supplied to the motor  94  thereby to control the rotation angle of the valve. The motor  94  may be equipped with a hall sensor (not shown) to detect the rotation angle and to send a signal representing the detected rotation angle to the ECU  98 . 
         [0030]    The EGR channel  46  accommodates a deflector  60  on the upstream side of the annular passage  48  relative to the flow of EGR gas. The deflector  60  is substantially in a plate shape and is formed of a metallic material such as stainless steel and/or an aluminum alloy. The deflector  60  is affixed to an inner periphery of the EGR channel  46 , by for example, welding. The deflector  60  may be a separate component from the inner pipe  50 . 
         [0031]    In  FIG. 3 , the deflector  60  extends in parallel with a center axis (horizontal center)  40 H of the outer pipe  40 , a center axis (horizontal center)  50 H of the inner pipe  50 , a center axis of the EGR channel  46 , and the radial direction of the inner pipe  50 . The deflector  60  extends perpendicularly to the axial direction of the inner pipe  50  through the EGR channel  46  and extends perpendicularly to the outer periphery of the inner pipe  50 . The deflector  60  closes off a passage area of the EGR channel  46  between the 
         [0032]    EGR valve  90  and the inner pipe  50 . The deflector  60  substantially partitions the EGR channel  46  into an upper channel (first channel)  46 A and a lower channel (second channel)  46 B. 
         [0033]    The deflector  60  further partitions the annular passage  48  into an upper arc passage (first arc passage)  48 A and a lower arc passage (second arc passage)  48 B at one end (root end). The upper channel  46 A communicates with the upper arc passage  48 A. The lower channel  46 B communicates with the lower arc passage  48 B. The upper channel  46 A and the lower channel  46 B ultimately communicate with each other through the upper arc passage  48 A and the lower arc passage  48 B at a boundary  48 C between the upper arc passage  48 A and the lower arc passage  48 B. The boundary  48 C is located at the opposite side of the inner pipe  50  from the deflector  60 . The deflector  60  partitions the annular passage at the opposite side of the inner pipe  50  from the boundary  48   c.    
         [0034]    As shown by the arrows in  FIG. 3 , EGR gas passes around the EGR valve  90  and further flows along the deflector  60 . Thus, the deflector  60  may deflect the flow of EGR gas to flow around the outer periphery of the inner pipe  50  through the annular passage  48 . 
         [0035]    The present configuration enables to flow EGR gas from the EGR passage  172  to pass around the EGR valve  90  and to pass through the upper channel  46 A or the lower channel  46 B of the EGR channel  46 . The present configuration further enables to flow EGR gas to pass through the upper arc passage  48 A and the lower arc passage  48 B of the annular passage  48  circumferentially and further to flow the EGR gas into the inner passage  52  radially inward through the through holes  56 . The annular passage  48  leads EGR gas to flow from the EGR channel  46  and to flow entirely around the outer periphery of the inner pipe  50  toward the opposite side of the EGR channel  46 . Thus, the annular passage  48  may enable to distribute EGR gas evenly around the inner pipe  50  in the circumferential direction. The ECU  98  is configured to control the position of the EGR valve  90  to manipulate a quantity of EGR gas flowing through the EGR channel  46  into the annular passage  48 . 
         [0036]    In  FIG. 2 , the curvature defined by the inner periphery of the inner pipe  50  may be configured to throttle the inner passage  52  and to cause Venturi effect at the intermediate portion  54 . The curvature may be configured to increase flow velocity of fresh air and to cause negative pressure at the intermediate portion  54 . Thus, the curvature may facilitate to induce EGR gas from the annular passage  48  on the radially outside of the inner pipe  50  into the inner passage  52  through the through holes  56 . In this way, the curvature may facilitate to feed EGR gas into the inner passage  52  and to blend the EGR gas with fresh air. The inner pipe  50  has a cross section having a vertical center  50 V, the horizontal center  50 H, and a center point  50 C, which is an intersection between the vertical center  50 V and the horizontal center  50 H. The inner periphery of the outer pipe  40  has a cross section defining an inscribe circle  401 , which has a vertical center  40 V, the horizontal center  40 H, and a center point  40 C, which is an intersection between the vertical center  40 V and the horizontal center  40 H. 
         [0037]    In the present example, as shown in  FIG. 3 , the inner pipe  50  and the outer pipe  40  are substantially coaxial with each other. Specifically, the center point  50 C of the inner pipe  50  and the center point  40 C of the inscribe circle  401  of the outer pipe  40  substantially coincide with each other. 
         [0038]    The through holes  56  extends from the annular passage  48  toward the inner passage  52  to throttle EGR gas flowing from the through holes  56 . The present configuration enables to flow EGR gas from the outside of the inner pipe  50  through the through holes  56  into the inner passage  52 . After passing through the through holes  56 , EGR gas may be expanded and diffused into fresh air passing through the inner passage  52 . Thus, the present configuration may enable EGR gas to be homogeneously and evenly blended with fresh air in the inner passage  52  to produce uniform mixture gas. 
         [0039]    The deflector  60  may restrict a stream line of EGR gas from passing across the horizontal centers  40 H and  50 H. That is, the deflector  60  may restrict EGR gas from flowing from the lower channel  46 B into the upper channel  46 A and may restrict EGR gas from flowing from the upper channel  46 A into the lower channel  46 B. In this way, the deflector  60  may rectify stream lines of EGR gas to extend horizontally within the upper channel  46 A or the lower channel  46 B thereby to extend selectively into the upper arc passage  48   a  or the lower arc passage  48   b.  Thus, the deflector  60  may rectify EGR gas to flow smoothly along the outer periphery of the inner pipe  50 . The deflector  60  may enable the streamlines of EGR gas to extend further toward the boundary  48   c  of the annular passage  48  on the opposite side of the EGR channel  46 . That is, the deflector  60  may enable EGR gas to access the opposite side of the EGR channel  46  across the inner pipe  50 . 
         [0040]    In  FIG. 3 , the solid line represents the EGR valve  90  substantially at a full open position. When the EGR valve  90  is substantially at the full open position, the EGR valve  90  may be continuously positioned with the deflector  60  to form extended passages on the upper side and the lower side in the drawing to be respectively communicated with the upper channel  46 A and the lower channel  46 B continuously. Thus, the EGR valve  90  and the deflector  60  may form elongated passages to linearly rectify stream lines of EGR gas toward the boundary  48 C across the inner pipe  50 . 
         [0041]    In the present example, the deflector  60  is offset from the horizontal centers  40 H and  50 H upward in the vertical direction. That is, the deflector  60  is offset from the center of the EGR channel  46 . The deflector  60  defines the upper channel  46 A and the lower channel  46 B, such that the passage area of the upper channel  46 A is less than the passage area of the lower channel  46 B. 
       Second Embodiment 
       [0042]    As shown in  FIG. 5 , according to the present second embodiment, the deflector  60  is offset from the horizontal centers  40 H and  50 H downward in the vertical direction. The deflector  60  defines an upper channel  246 A and a lower channel  246 B, such that the passage area of the upper channel  246 A is greater than the passage area of the lower channel  246 B. 
       Third Embodiment 
       [0043]    As shown in  FIG. 6 , according to the present third embodiment, a deflector  360  is located along the horizontal centers  40 H and  50 H to extend along the horizontal direction. The deflector  360  defines an EGR channel  346  including an upper channel  346 A and a lower channel  346 B. The upper channel  246 A and the lower channel  246 B may be substantially symmetric to each other relative to the horizontal centers  40 H and  50 H. The deflector  360  has a root end and a tip end. The root end is adjacent to the inner pipe  50 . The tip end is located on the opposite side of the deflector  60  from the root end. The deflector  360  has the tip end having a width D1 and the root end having a width D2, such that the widths D1 and D2 substantially satisfy the following relation: D2=2×D1. The deflector  360  increases in cross section from the tip end toward the root end. The upper channel  346 A and the lower channel  346 B extend from the tip end of the deflector  360  toward the root end of the deflector  360  to be inclined outward relative to the horizontal centers  40 H and  50 H. 
         [0044]    The deflector  360  may direct the upper channel  346 A and the lower channel  346 B radially outward smoothly toward the outer periphery of the inner pipe  50 . 
       Fourth Embodiment 
       [0045]    As shown in  FIG. 7 , according to the present fourth embodiment, a deflector  460  is located along the horizontal centers  40 H and  50 H to extend along the horizontal direction. The deflector  460  defines an EGR channel  446  including an upper channel  446 A and a lower channel  446 B. The upper channel  246 A and the lower channel  246 B may be substantially symmetric to each other relative to the horizontal centers  40 H and  50 H. 
         [0046]    The deflector  460  has a tip end having a width D1 and a root end having a width D3, such that the widths D1 and D3 substantially satisfy the following relation: D3=6×D1. That is, the widths D1 and D3 satisfy the following relation: D3&gt;&gt;D1. The cross section of the deflector  460  increases from the tip end toward the root end. The root end of the deflector  460  has curved ends  462 A and  462 B extending outward from the root end smoothly toward the outer periphery of the inner pipe  50 . The deflector  460  has a hollow  464  substantially at the center. 
         [0047]    A housing  420  defines an upper curvature  440 A on the upper side of the upper channel  446 A and defines a lower curvature  440 B on the lower side of the lower channel  446 B. The curvatures  440 A and  440 B may extend outward relative to the horizontal centers  40 H and  50 H and may extend substantially along the outer periphery of the deflector  460 . 
         [0048]    The upper curvature  440 A and the deflector  460  form the upper channel  446 A directed from the tip end of the deflector  460  toward the root end of the deflector  460  smoothly toward the annular passage  48 . The lower curvature  440 B and the deflector  460  form the lower channel  446 B directed from the tip end of the deflector  460  toward the root end of the deflector  460  smoothly toward the annular passage  48 . 
         [0049]    The curved ends  462 A and  462 B may connect the upper channel  446 A and the lower channel  446 B smoothly toward the annular passage  48 . 
       Fifth Embodiment 
       [0050]    As shown in  FIG. 8 , according to the present fifth embodiment, an inner pipe  550  has through holes, which have different diameters. Specifically, through holes  556 A,  556 B,  556 C are formed to have diameters increased from the side of the EGR channel  46  toward the opposite side of the EGR channel  46 . More specifically, the through holes  556 A have an inner diameter d1. The through holes  556 B have an inner diameter d2. The through holes  556 C have an inner diameter d3. The diameters d1, d2, d3 satisfy the following relation: d1&gt;d2 &gt;d3. In the present example, similarly to the first embodiment, the inner pipe  550 , and the outer pipe  40  are substantially coaxial with each other. 
       Sixth Embodiment 
       [0051]    As shown in  FIG. 9 , according to the present sixth embodiment, an inner pipe  650  is offset relative to the outer pipe  40 , such that the vertical center  40 V of the outer pipe  40  is offset from the vertical center  50 V of the inner pipe  50  in the radial direction. More specifically, the outer pipe  40  and the inner pipe  50  may be offset in relation to each other so that a distance between the outer pipe  40  and the inner pipe  50  progressively decreases from the EGR channel  46  to the opposite side of the EGR channel  46 . Therefore, an annular passage  648  formed between the outer pipe  40  and the inner pipe  650  is gradually reduced in passage area toward the opposite side of the EGR channel  46 . 
         [0052]    In the present sixth embodiment, a deflector  660  extends from the inner pipe  50  through an EGR passage  646 . The deflector  660  may be greater in length than the deflector  60  according to the first embodiment. The deflector  660  may form an upper channel  646 A and a lower channel  646 B in the EGR passage  646 . The upper channel  646 A and the lower channel  646 B may be greater in length than the upper channel  46 A and the lower channel  46 B according to the first embodiment. 
       Seventh Embodiment 
       [0053]    In  FIG. 10 , bold arrows show the flow of fresh air on the upstream side and the flow of mixture gas on the downstream side. According to the present seventh embodiment, in  FIG. 10 , which is the sectional view, an inner pipe  750  has two through holes  756  on the upstream side of a centerline  48 D of the annular passage  48  and one through hole  756  on the downstream side of the centerline  48 D of the annular passage  48 . That is, in the entire circumferential direction, three through holes  756  are arranged on the upstream side in total, and two through holes  756  are arranged on the downstream side in total. In the present configuration, the through holes  756  are arranged alternately in the circumferential direction. That is, the through holes  756  are arranged alternately relative to the axial direction of the inner pipe  50 . 
       Other Embodiment 
       [0054]    The deflector may be located on the horizontal center. The deflector may be in an arc shape. In this case, the deflector may form an upper channel and a lower channel to have curved passages. The deflector may be inclined relative to the horizontal center. In this case, the deflector may form an upper channel and a lower channel to have inclined passages. The deflector may be integrally formed with the inner pipe. 
         [0055]    Various combinations of the deflector, the inner pipe, and other components of the EGR device according to the above-described embodiments may be arbitrary employed. 
         [0056]    The through holes may employ various forms. For example, the through holes may employ various numbers, various sizes, various arrangements, and/or various shapes. For example, the through holes may employ various shapes such as an oval shape, a polygonal shape, or a star shape. Various combinations of the through holes of the above-described embodiments may be arbitrary employed. 
         [0057]    The through holes may be unevenly arranged. For example, the through holes may be concentrically formed on the opposite side of the EGR channel. The through hole(s) on the side of the EGR channel may be omitted. The inner pipe may not have the curvature on the inner periphery. 
         [0058]    It should be appreciated that while the processes of the embodiments of the present disclosure have been described herein as including a specific sequence of steps, further alternative embodiments including various other sequences of these steps and/or additional steps not disclosed herein are intended to be within the steps of the present disclosure. 
         [0059]    While the present disclosure has been described with reference to preferred embodiments thereof, it is to be understood that the disclosure is not limited to the preferred embodiments and constructions. The present disclosure is intended to cover various modification and equivalent arrangements. In addition, while the various combinations and configurations, which are preferred, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure.