FR2893363A1 - VALVE AND DEVICE FOR RECYCLING EXHAUST GAS FOR AN ENGINE - Google Patents

Abstract

A valve (3) is connected to a cooler (2) for cooling the recycled exhaust gas in an engine intake system. It includes a body (4) having a coolant inlet passage (42, 44) communicating with an inlet of the cooler (2), and a cooler outlet passage (52) communicating with an outlet of the cooler (2). The body includes a first seat (11) defining a bypass passage (35), and further includes a movable shutter (5). When the shutter (5) is lifted from the first seat (11), the cooler inlet passage (42, 44) communicates with the cooler outlet passage (52) through the bypass passage (35) bypassing the cooler. When the shutter (5) is applied to the first seat (11), it is in a fully closed position of the bypass, in which it closes the bypass passage (35).

Description

VALVE AND DEVICE FOR RECYCLING EXHAUST GAS FOR AN ENGINE

  The present invention relates to a valve and an exhaust gas recirculation device comprising the valve. According to EP0987427, an exhaust gas recirculation device comprises an EGR cooler module (EGR for "Exhaust Gas Recirculation"). As shown in FIG. 22, the EGR cooler module is made by integrating an EGR cooler 1101 and a switch valve 1102. The EGR cooler 1101 cools the exhaust gas recirculation gas (EGR gas) by exchanging the exhaust gas. heat with the engine cooling water. The switching valve 1 102 communicates with the upstream of the EGR cooler 1101, when considering the flow direction of the EGR gas. The exhaust gas recirculation device is placed in an intermediate position in exhaust gas recirculation pipes (EGR pipes) 1120, 1130 for controlling the exhaust gas temperature c. in accordance with an operating condition dru! 4V - tor. The exhaust gas is exhausted from the engine, and the exhaust gas is partially recycled in the form of EGR gas, from an exhaust system, to an engine intake system, through the EGR 1120 hoses. , 1130. The EGR pipe 1120 includes a branch pipe through which an EGR gas flow passage forms a branch upstream of a body 1103, when considering EGR gas flow. The branch pipe is connected to chiller inlet passages 1121, 1123. The EGR pipe 1130 comprises a collection pipe through which the EGR gas flow passages collect downstream of the body 1103, where the circulation of the EGR gas is considered. The collection pipe is connected to cooler outlet passages 1122, 1105.

  The EGR cooler 1101 has a U-shaped cooling passage through which the EGR gas flows from a cooler inlet passage 1104 to a cooler outlet passage 1105. The body 1103 has a transition passage of branch 1106 which extends parallel to the chiller inlet passage 1104 and the chiller outlet passage 1105. The EGR gas bypasses the EGR cooler 1101 while flowing through the bypass passage 1106. The body 1103 has a partition wall 1107 which separates both the cooler inlet passage 1104 and the cooler outlet passage 1105 from the bypass passage 1106. The body 1103 rotatably supports an axis 1109 which passes through the partition 1107. First and second shutters 1111, 1112 are joined to the axis 1109. The first shutter 1111 opens and closes the cooler inlet passage 1104. The second shutter 1112 opens and closes The axis 1109 is coupled to a rod 1115 of an actuator 1110 through a connecting plate 1113 and an axis 1114. The first shutter 1111 is inclined by about 90 degrees. relative to the second shutter 1112. When the first shutter 1111 is in a full open position of the cooler, the second shutter 1112 is in a fully closed position of the bypass. When the first shutter 1111 is in a fully closed position of the cooler, the second shutter 1112 is in a full open position of the bypass.

  When the first shutter 1111 is in the full open position of the cooler, the second shutter 1112 is in the fully closed position of the bypass. In this condition, the temperature of the low temperature EGR gas, which is cooled through the EGR cooler 1101, increases due to high temperature EGR gas leakage through clearance between the wall surface of the bypass passage 1106 and the second shutter 1112. Therefore, the EGR gas, which is recycled into the engine intake system, is not sufficiently cooled, and the amount of nitrogen oxide (NOx) in the exhaust gas does not can not be significantly reduced.

  When the first shutter 1111 is in the complete shutter position of the cooler, the second shutter 1112 is in the fully open position of the shunt. In this condition, EGR gas leaks through clearance between the wall surface of the cooler inlet passage 1104 and the first shutter 1111. The temperature of this leakage EGR gas is lowered by passage through the EGR cooler 1101 As a result, the temperature of the EGR gas, which is recycled to the engine intake system, becomes low, and a reheat operation of the intake air can not be sufficiently performed. As a result, the amount of hydrocarbons (HC) in the exhaust gas can not be significantly reduced. In view of the foregoing and other problems, an object of the present invention is to provide a valve for an exhaust gas recirculation device, the valve being capable of reducing its leakage. Another object is to provide an exhaust gas recycle device having the valve. According to one aspect of the present invention, a valve, which is connected to a cooler for cooling recycled exhaust gas in an engine intake system, comprises a body which has a coolant inlet passage communicating with an inlet of the cooler. The body further includes a cooler outlet passage communicating with an outlet of the cooler. The body includes a first seat defining a bypass passage therein. The valve further comprises a shutter which is movable in the body. When the shutter is lifted from the first seat, the cooler inlet passage communicates with the cooler outlet passageway through the bypass passage, bypassing the cooler. When the shutter is applied to the first seat, the shutter is in a fully closed position of the bypass in which the valve closes the bypass passage. The complete closure position of the bypass is placed between the cooler inlet passage and the cooler outlet passage. In another aspect of the present invention, an exhaust gas recirculation device for an engine comprises a cooler that cools recycled exhaust gas in an engine intake system. The cooler has an inlet and an outlet through which the exhaust gas passes. The exhaust gas recirculation device further comprises a valve that includes a body having a coolant inlet passage communicating with the cooler inlet. The body further includes a cooler outlet passage communicating with the outlet of the cooler. The body includes a first seat defining a bypass passage therein. The valve further comprises a shutter which is movable in the body. When the shutter is lifted from the first seat, the cooler inlet passage communicates with the cooler outlet passageway through the bypass passage, bypassing the cooler. When the shutter is applied to the first seat, the shutter is in a fully closed position of the bypass, wherein the shutter closes the bypass passage. The complete closure position of the bypass is between the cooler inlet passage and the cooler outlet passage. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings: Figure 1 is a schematic view showing an exhaust gas recirculation device; Fig. 2 is a sectional view showing an EGR cooler module of the exhaust gas recirculation device; Fig. 3 is a perspective view showing a valve of the EGR cooler module according to a first embodiment; Figure 4 is a perspective sectional view showing the valve in which a shutter is incorporated; Fig. 5 is a perspective section showing the shutter, which is in a fully closed position of the bypass in the valve; Fig. 6 is a perspective section showing the shutter, which is in a fully closed position of the cooler in the valve; Fig. 7 is a perspective sectional view showing an EGR circulation passage when the shutter is in the fully closed position of the bypass; Figure 8 is a perspective sectional view showing an EGR flow passage when the shutter is in the fully closed position of the cooler; Figure 9 is a longitudinal section showing an actuator of the valve; Fig. 10 is a perspective sectional view showing a shutter-shaped shutter, which is in a fully closed position of the shunt in the valve according to a second embodiment; Fig. 11 is a perspective section showing the shutter-shaped shutter, which is in an opening operation of the bypass in the valve; Fig. 12 is a perspective sectional view showing the flap-shaped shutter, which is in the fully closed position of the cooler in the valve; Fig. 13 is a perspective view showing the valve; Figure 14 is a longitudinal section showing the actuator of the valve; Figs. 15 (a), 15 (b) are cross-sections showing shutter 20 in the form of a shutter, and Fig. 15 (c) is a perspective view showing shutter-shaped shutter; Fig. 16 is a graphical representation showing a relationship between the required actuation force, the load, and the fluidic force; Fig. 17 is a perspective view, partly in section, showing a protective block mounted about an axis and a seal for the gas in a valve according to a third embodiment; Fig. 18 is a sectional view showing the EGR cooler module of the exhaust gas recirculation device; Fig. 19 is a perspective section showing the shutter, which is in a fully closed position of the bypass in the valve; Fig. 20 is a perspective section showing the shutter, which is in a fully closed position of the cooler in the valve; Fig. 21 is a view showing components mounted on the axis; and Fig. 22 is a sectional view showing an EGR cooler module of an exhaust gas recirculation device according to a comparative example. First Embodiment The first embodiment is hereinafter described with reference to FIGS. 1-9. As shown in FIG. 1, an exhaust gas recirculation device (EGR device) comprises an EGR cooler module 1 The EGR device cools the exhaust gases using an EGR cooler 2, which performs the function of an exhaust gas cooler. An internal combustion engine E such as a diesel engine has combustion chambers that exhaust gas. The EGR device partially introduces the exhaust gas into an engine E intake system, thereby recycling exhaust gas. The EGR device comprises exhaust gas recirculation pipes (EGR pipes) 16, 17 and an exhaust gas recirculation valve (EGR control valve) 19. The EGR pipes 16, 17 are respectively connected to an exhaust gas recirculation pipe (EGR valve). exhaust pipe 14 and an intake pipe 15 of the engine E. The exhaust gas exhausted from the engine 1 is partially recycled in the intake pipe 15 of the engine E in the form of EGR gas, through the EGR pipes 17. The EGR pipes 16, 17 define an exhaust gas recirculation passage (EGR passage). The EGR control valve 19 controls continuously or stepwise a quantity (EGR quantity) of EGR gas passing through the EGR passage. The exhaust pipe 14 defines an exhaust passage through which the exhaust gas passes. The intake pipe 15 defi nes an intake passage. The intake air is filtered through an air filter 20 and enters the combustion engine through the intake passage. The EGR cooler module 1 is installed in series between the EGR pipes 16, 17. The EGR pipe 16 is connected to an exhaust manifold of the exhaust pipe 14. The EGR pipe 17 is connected to an intake manifold of the intake pipe 15 or to a balance chamber 35. The engine E has a cooling water circuit through which cooling water is supplied to the EGR cooler module 1. The cooling water circuit includes cooling water pipes 22, 24 and a pump. water (not shown). The cooling water is recycled from a water jacket (not shown) of the engine E into a cooling water inlet pipe (hot water pipe) 21 of the EGR cooler module 1 to through the cooling water pipe 22. The cooling water is recycled from a cooling water outlet pipe (hot water pipe) 23 of the EGR cooler module 1 into the water jacket of the engine E, through a radiator and the cooling water pipe 24. The water pump circulates the cooling water through the cooling water circuit. The cooling water and the atmosphere exchange heat with each other in the radiator so that the cooling water is cooled to a predetermined temperature range of 75 to 80 ° C and is returned to the jacket. The EGR cooler module 1 is made by integrating the EGR cooler 2 with a switching valve 3. The EGR cooler 2 2C) cools the EGR gas at a high temperature by exchanging heat with it. cooling water. The diverting valve 3 is connected to an outlet and an inlet of the EGR cooler 2. The EGR cooler module 1 forms part of the EGR pipes 16, 17 of the EGR device and part of the cooling water pipes 22, 24 of the re-cooling water circuit. The switching valve 3 comprises a body 4 of a three-way valve and two positions, and first and second valve seats (first and second cylindrical members) 11, 12. The body 4 defines inside a first rectilinear passage 31a, an L-shaped passage 32a and a bypass passage. The bypass passage communicates the first rectilinear passage 31a with the L-shaped passage 32a. The three-way and two-position shutter is movable in the body 4. The three-way, two-position shutter is actuated to take two positions including a complete closure position of the bypass (full open position of the cooler) and a complete closing position of the cooler (full open position of the bypass). The three-way, two-position shutter comprises a shutter member (shutter with shutter) which is applied to the first and second seats 11, 12. The first straight passage 31a and the L-shaped passage 32a define a passage chiller communication system through which the EGR gas is recycled into the engine intake system through the EGR cooler 2. The EGR gas bypasses the EGR cooler 2 through the bypass passage, so that the EGR gas be recycled in the engine intake system E.

  The EGR cooler 2 is a water-cooled exhaust gas cooler. The high temperature EGR gas is introduced into the EGR cooler 2 from the body 4 of the diverting valve 3. The low temperature cooling water is introduced into the EGR cooler 2 from the cooling water pipe. 22. The high temperature EGR gas exchanges heat with the low temperature cooling water in the EGR cooler 2, so that the high temperature EGR gas is cooled to a temperature below a predetermined temperature. The EGR cooler 2 contains tubes (not shown). The EGR cooler 2 has a cooling water circuit (not shown) through which cooling water is recycled to circulate around the tubes. The cooling water enters the hot water pipe 21 from the cooling water pipe Z2. The cooling water enters the water-cooling pipe 24 from the hot water pipe 23, which is mounted on the body 4 of the diverting valve 3. For example, each of the tubes is a tube U-shaped through which EGR gas flows from the inlet of the EGR cooler 2 to the outlet of the EGR cooler 2, following a U-shaped path. The EGR cooler 2 has a group of first passes of exhaust, through which the EGR gas flows from the body 4, and second exhaust passages through which the EGR gas flows out of the body 4. As shown in FIG. exhaust and the second exhaust passages are separated by a partition 25.

  Referring to FIGS. 1 to 3, the body 4 is connected to the inlet and the outlet of the EGR cooler 2. The body 4 is made of metal, in one piece, for example cast iron or aluminum die cast. Referring to Figures 3, 4, 6, it is noted that the body 4 has an inlet flange 26 and an outlet flange 27. The inlet flange 26 is attached to a flange (not shown) of the EGR pipe 16, which is upstream in the EGR gas flow, using an assembly element such as a screw. The outlet flange 27 is attached to a flange (not shown) of the EGR pipe 17, which is downstream in the EGR gas flow, using an assembly member such as a screw. The body 4 has an EGR cooler flange 29. The EGR cooler flange 29 is attached to a flange (not shown) of the inlet and outlet of the EGR cooler 2 using an assembly member such as a screw. The body 4 has a straight pipe portion 31 and an L-shaped pipe portion 32. The L-shaped pipe portion 32 has a substantially perpendicular bent passage which is bent at a predetermined angle such as 90. The straight pipe portion 31 defines inside the first rectilinear passage 31a. The EGR gas is introduced into the EGR cooler 2 from the EGR pipe 16, through a first inlet port 41 of the EGR cooler module 1 and the first tapered passage 31a. The L-shaped pipe portion 32 defines inside the L-shaped passage 32a. The EGR gas is introduced into the EGR pipe 17 from the EGR cooler 2 through the L-shaped passage 32a and a second outlet 55 from the EGR cooler module 1. - The body 4 has a partition therein separator 33 formed in one piece with the rest of the body. The partition wall 33 is placed between the straight pipe portion 31 and the L-shaped pipe portion 32. The partition wall 33 hermetically separates the first straight passage 31a from the L-shaped passageway. 32a.

  The partition wall 33 has bypass passages 34, 35 which define a short cut between the first rectilinear passage 31a and L-shaped passage 32a. The partition wall 33 has a first communication hole through which the straight pipe portion 31 communicates with the L-shaped pipe portion 32. The reciprocal pipe portion 31 has a second communication hole through which the Upstream of the straight pipe portion 31 communicates with the downstream portion of the straight pipe portion 31. The L-shaped passage 32a and the bypass passages 34, 35 meet, i.e., join into each other. a collecting portion (cooler outlet passage) 53. The cooler outlet passage 53 is placed between a cooler outlet passage 52 and the second outlet port 55. The partition wall 33 has a bearing shutter 36 substantially cylindrical. The bearing 36 rotatably supports a shutter pin 6 via a bearing component (not shown). The bearing component has a sliding hole along which the outer circumferential periphery of the shutter axis 6 slides. The body 4 has an opening around an axial end of the bearing 36. A plug 37 is tightly fitted, tightly in the body 4 to close the opening of the bearing 36. A bracket 63 is fixed to the body 4 by using an assembly element such as a screw 39. A vacuum actuator 9 is fixed to the body 4 by The body 4 has a cooling water inlet and a cooling water outlet in which the hot water pipes 21, 23 are respectively tightened, waterproof way.

  The first rectilinear passage 31a extends substantially rectilinearly from the first inlet port 41 to a first outlet port 45. The first straight passageway 31a extends rectilinearly substantially perpendicular to the passageways axes. The first rectilinear passage 31a comprises cooler inlet passages 42 to 44 and the first outlet orifice 45. The first inlet orifice 41 defines an opening in the upstream end of the screw body 4. with respect to the circulation of the exhaust gas. The first outlet port 45 defines an opening to the inlet of the EGR cooler 2. The first inlet port 41 defines an inlet port of the EGR cooler module 1. The first outlet port 45 communicates with the ends of the inlet of the EGR cooler tubes 2. The first straight passage 31a comprises the cooler inlet passages 42 to 44 communicating with the inlet of the EGR cooler 2. The cooler inlet passages 42 to 44 are between the first orifice 41 and the first outlet 45. The first outlet 45 has an axis that substantially coincides with the axis of the first inlet port 41. The cooler inlet passage 42 also performs the function of a shutter chamber for rotatably housing the shutter 5. The cooler inlet passage 42 also performs the function of a branch portion. The cooler inlet passage 42 communicates with the bypass passage 34 through the branch portion, and defines therebetween a substantially T-shaped section. The L-shaped passage 32a is bent substantially perpendicular to half-way between the second inlet port 51 and the second outlet port 55. The L-shaped passage 32a includes the second inlet port 51 and the cooler outlet passages 52, 53. The second inlet port 51 defines an opening in the outlet of the EGR cooler 2. The second outlet port 55 defines an opening in the downstream end of the body 4 with respect to the flow of the exhaust gas. The second inlet port 52 communicates with the outlet ends of the EGR cooler tubes 2. The second outlet port 55 defines an outlet port of the EGR cooler module 1. The L-shaped passage 32a includes the exit passages cooler 52, 53. The cooler outlet passages 52, 53 are defined between the second inlet port 51 and the second outlet port 55. The second inlet port 51 and the second outlet port 55 define one another. ..an angle that is substantially 90. The cooler outlet passages 52, 53 communicate with the outlet of the EGR cooler 2. The cooler outlet passage 53 also performs the function of a mating portion. The cooler outlet passage 53 communicates with the bypass passage 35 through the joining portion, and defines between them a substantially T-shaped section. The cooler outlet passage 53 also serves the function of a bypass outlet passage through which high temperature EGR gas flows from the bypass passage 35. The cooler inlet passage 42 performs the branch part function, wherein the bypass passages 34, 35 branch off from the first rectilinear passage 31a. The cooler outlet passage 53 performs the function of the collecting portion, in which the bypass passages 34, 35 meet with the L-shaped passage 32a. The bypass passages 34, 35 directly communicate the cooler inlet passage 42 with the cooler outlet passage 53 without passing through the EGR cooler 2. The EGR gas bypasses the EGR cooler through the bypass passages 34 , 35. The bypass passages 34, 35 are substantially perpendicular to the axis of the first rectilinear passage 31a. The axes of the bypass passages 34, 35 are located along a vertical line, which is substantially perpendicular to the axis of the first rectilinear passage 31a. The bypass passages 34, 35 and the cooler outlet passage 53 extend substantially rectilinearly from the branch portion, which is between the bypass passages 34, 35 and the first straight passage 31a, direction of the second outlet port 55 of the body 4. The bypass passages 34, 35 and the cooler outlet passage 53 extend generally along the axes of the bypass passages 34, 35.

  The bypass passages 34, 35 and the cooler outlet passage 53 fulfill the function of a second straight passage. The cooler inlet passages 42 to 44 and the first outlet port 45 define a coolant inlet communication passage. The second inlet port 51 and the cooler outlet passages 52, 53 define a cooler outlet communication passage. The cooler inlet passage 42, the bypass passages 34, 35 and the cooler outlet passage 53 define a bypass flow path. The cooler outlet passage 52 of the L-shaped pipe portion 32 internally defines a throat 56. The throat 56 has a cross-section smaller than the cross-sectional area of the second inlet 51 of the cooler outlet passage 52. The throat 56 has a cross-section that allows the flow of a required amount of EGR gas through the interior space (cooler outlet passages 52, 53) of the shaped pipe portion. from L 32.

  The constriction 56 is defined by a protrusion 57 and the like. The protrusion 57 is integrated with the partition wall 33. The protrusion 57 projects partially from the passage wall of the partition wall 33 so that the protrusion 57 reduces the cross section of the coolant outlet passage. 52. Projection 57 protrudes to define the cross section of cooler outlet passage 52 to provide the required amount of EGR gas. The protrusion 57 prevents the soot and deposits contained in the exhaust gas from entering the bearing of the shutter shaft 6. The required amount of EGR gas can be determined on the basis of the design work of the structure 4. The three-way and two-way shutter comprises a disc-shaped shutter 5, a columnar shutter axis 6, and a shutter lever 7 having a V-shaped cross-section. 5 can rotate in the cooler inlet passage 42, so that the shutter 5 selectively opens one of the cooler inlet passages 43, 44 and bypass passages 34, 35, and closes the other cooler inlet passages 43, 44 and bypass passages 34, 35. The shutter shaft 6 is rotatably supported by the bearing 36 of the body 4. The shutter lever 7 connects the shutter 5 to the shutter pin 6. The shutter 5 is made of a metallic material, which has excellent properties of heat resistance and corrosion resistance, so as to have substantially a disc shape. The metallic material may be stainless steel such as SUS 304. The obturator 5 has a back surface in the direction of its thickness. The rear surface of the shutter 5 is applied to the first seat 11 of the body 4 and is lifted therefrom, which has the effect of closing and opening the bypass passages 34, 35. The shutter 5 has a front surface on the other side of the rear surface in the direction of its thickness. The front surface of the shutter 5 is applied to and lifted from the second seat 12 of the body 4, thereby closing and opening the cooler inlet passages 43, 44. The three-way, two-position shutter is operated between two positions including the complete closure position of the bypass 35 and the complete closed position of the cooler. The complete closing position of the bypass (full open position of the cooler) is shown in Figures 2, 4, 5. The complete closed position of the cooler (full open position of the bypass) is represented by Figure 6. The rear surface of the shutter 5 is applied and fitted to the first seat 11 in the fully closed position of the bypass, so that the bypass passages 34, 35 are closed, and the passages of cooler inlet 43, 44 are open, in a fully open condition. The front surface of the shutter 5 is applied and adjusted to the second seat 12 in the complete closing position of the cooler, so that the cooler inlet passages 43, 44 are closed, and the bypass passages are closed. 34, 35 are open, in a full open condition. When the shutter 5 is in a condition of complete closure of the bypass, the shutter 5 is in the complete closed position of the shunt. When the shutter 5 is in a condition of complete closure of the cooler, the shutter 5 is in the complete closed position of the cooler. An operating angle (allowable angle) of the shutter 5 between the complete closure position of the shunt and the complete closure position of the cooler is an acute angle less than 90. The operating angle of the shutter 5 may be an acute angle that is greater than 0 and less than 90, excluding the right angle (90). The operating angle of the shutter 5 is preferably-equal to or greater than 20 and equal to or less than 70. The shutter operation ae 5 may more preferably be equal to or greater than 30 and equal to or less than 60. The operating angle of the shutter 5 may even more preferably be equal to or greater than 40 and equal to or less than 50. The operating angle of the shutter 5 shown in FIG. 2 is about 49. When the shutter 5 is in the closed position of the bypass, the shutter 5 is applied to a first seat portion 91 of the first seat 11. The first seat portion 91 of the first seat 11 defines, that is, determines, the complete closure position of the bypass. When the shutter 5 is in the fully closed position of the shunt, the normal to the front surface of the obturator 5 is substantially perpendicular to the axis of the first rectilinear passage 31a and is substantially parallel to the vertical direction of the shunt. Figure 2. When the shutter 5 is in the full open condition of the bypass, the shutter 5 is applied to a second seat portion 92 of the second seat 12. The second seat portion 92 of the second seat 12 defines that is, determines the complete closed position of the cooler. When the shutter 5 is in the complete opening condition of the bypass, the shutter 5 is opposite to the first inlet orifice 41 of the body 4. In this condition of complete opening of the bypass, the normal to the surface rear of the shutter 5 is inclined by a predetermined angle, in a range such as 40 to 50, with respect to a vertical line which is substantially perpendicular to the axis of the first straight passage 31a of the body 4, in the direction of the passages When the shutter 5 is in the open condition of the bypass, the normal to the rear surface of the shutter 5, which is opposed to the first inlet 41 of the body 4 , is inclined forwards, in the direction of the first inlet port 41, by the predetermined angle in a range such as 40 to 50 C. The shutter axis 6 is rotatably supported by the peri2 () circumferential circumferential hole of bearing axis hole 36 mounted in the partition wall 33 of the housing 4. The shutter shaft 6 is supported by the bearing 36 via the bearing component and a sealing member., Le: - 3lier 36 is mounted on the partition wall 33 (h # Ic protection). The shutter pin 6 is formed in one piece and is made of a metallic material which has excellent heat resistance and corrosion resistance properties. The metal material of the shutter shaft 6 may be stainless steel such as SUS 304. The shutter shaft 6 has a support portion which is attached to a fixed end (first end) of the lever. shutter 7 connecting the shutter 5 to the shutter pin 6. A seal for the gas (not shown), such as a rubber seal, is placed between the inner circumferential periphery of the shutter Bearing 36 and the outer circumferential periphery of the shutter pin 7. The seal for the gas prevents soot and deposits contained in the exhaust gas from entering a set clearance between the Bearing component constituting the bearing 36 and the shutter pin 6. The shutter lever 7 is formed in one piece consisting of a metallic material, which has excellent heat resistance and resistance properties. to corrosion, so as to have a shape pr e-determined such as a V-shape. The metal material of the shutter lever 7 may be stainless steel as the SUS 304. The shutter lever 7 has a fixed end which is attached to the outer periphery of the shutter lever 7. a fixed part 74 of the shutter axis 6, by welding or others. The other free end (second end) of the shutter lever 7 is fixed to the rear surface of the shutter 5. The fixed end of the shutter lever 7 has substantially an arcuate shape or a cylindrical shape corresponding to the substantially in column form of the support portion of the shutter shaft 6. The fixed end of the shutter lever 7 is partially fixed to the outer circumferential periphery of the support portion of the shutter shaft 6, by welding or others. The shutter lever 7 has a free end which has a shape corresponding to a hole or the like defined in the center of the shutter 5. The free end of the shutter lever 7 has a groove coupled to the shutter 5, for example. The free end of the shutter lever 7 is fixed at the center of the rear surface of the shutter 5, by welding or the like. The shutter 5 is a shutter member which rotates about the fixed end of the shutter lever 7. The shutter 5 selectively opens one of the cooler inlet passages 43, 44 and bypass passages 34, 35, and closes the other of the cooler inlet passages 43, 44 and bypass passages 34, 35 on the free end side of the shutter lever 7. The shutter 5 is coupled, in a manner secured to the shutter pin 6, via the shutter lever 7. A shutter actuating device actuates the three-way shutter and two positions, which comprises the shutter 5, the shutter shaft 6 and the shutter lever 7, between the complete closed position of the bypass and the complete closed position of the cooler. As shown in FIGS. 2, 3, 9, the shutter actuating device comprises a vacuum actuator 9 and a connecting plate 62. The actuator 9 generates a driving force when applied thereto a depression, which is below atmospheric pressure.

  The connecting plate 62 fulfills the function of a motion transformation element which transforms a rectilinear movement of a rod 61 of the actuator 9 into a rotational movement of the shutter axis 6. The actuating device shutter operates the shutter 5 between the complete closure position of the bypass and the complete closed position of the cooler, using the actuating force of the actuator 9. The connecting plate 62 has an end of inlet having a coupling hole in which an end of the rod 61 of the actuator 9 engages. The connecting plate 62 has an outlet end having a coupling hole to which is fixed an axial end of the axis The axial end of the shutter pin 6 protrudes outwardly from the plug 37. Referring to FIG. 9, it will be noted that the actuator 9 comprises a diaphragm 60 , the rod 61, the connecting plate 62 (FIG. 3) and casings s 64, 65. The rod 61 moves axially integrally with the diaphragm 60, in correspondence with the movement of the diaphragm 60. The connecting plate 62 constitutes a connection means with the rod 61. The housings 64, 65 are assembled on A tray-shaped seat of the bracket 63. The diaphragm 60 is made of a rubber material in the form of a thin film, for example. The diaphragm 60 is interposed between the housings 64, 65. The diaphragm 60 hermetically separates the internal space of the housings 6-4, -6-5 into a vacuum chamber (first pressure chamber) 66 and an atmospheric chamber (second chamber 67. A depression is applied to the vacuum chamber 66. The atmospheric chamber 67 communicates with the atmosphere. The interior space of the housings 64, 65 contains a biasing element. For example, the biasing member is a coil spring 68 housed in the vacuum chamber 66. The biasing member generates a biasing force such as a spring force, to urge the diaphragm 60 downwardly in FIG. 9, so that the biasing element urges the shutter 5 to the full closed position of the shunt. The housing 64 is attached to a vacuum pipe 69. A vacuum is applied from an electric vacuum pump (not shown) and a vacuum control valve (not shown) to be introduced into the vacuum chamber. depression 66 through the vacuum pipe 69. The vacuum control valve may be actuated by a solenoid actuator or an electric motor.

  The actuator 9 introduces a depression in the depressurization chamber 66 from the electric vacuum pump, through the vacuum control valve. The actuator 9 moves the diaphragm 60 in the direction of its thickness, along the vertical direction in FIG. 9, by applying a pressure difference between the vacuum chamber 66 and the atmospheric chamber 67. Therefore, the actuator 9 axially moves the rod 61 together with the diaphragm 60. The axial movement of the rod 61 is transmitted to the shutter axis 6 via the connecting plate 62, so that the shutter axis 6 rotates. on a predetermined angle. As a result, the three-way, two-position valve is actuated between the complete closure position of the bypass and the complete closed position of the cooler. Thus, the seat position of the valve 5 is changed. The vacuum control valve and the electric vacuum pump apply a vacuum in the vacuum chamber 66 as the energy source of the actuator 9. The vacuum chamber 66 is placed on the end side. upper diaphragm 60, with respect to the direction of its thickness. The delirter control valve and the electric vacuum pump are actuated by the motor control unit (ECU) 10, being supplied with electricity from the ECU 10. The vacuum control valve controls a Vacuum applied in the vacuum chamber 66. The ECU 10 comprises a microcomputer having a central unit (CPU), a storage unit, an input circuit, an output circuit, 3C) and the like. The CPU performs command processing and arithmetic processing. The storage unit is a memory such as a ROM and a RAM that stores programs and data. When an ignition switch (not shown) is closed, the ECU 10 electronically controls the shutter 5 in accordance with the control programs and a table stored in the storage unit. When the ignition switch is open, the control of the ECU 10 is stopped forcibly. The various sensors transmit sensor signals which are subjected to an analog / digital conversion by an analog / digital converter, and are applied to the microcomputer of the ECU 10. The ECU 10 is electrically connected to various sensors such as a crankshaft angle sensor, an accelerator position sensor, a cooling water temperature sensor, an air flow meter, an intake air temperature sensor (temperature sensing unit 71), and an exhaust gas temperature sensor (exhaust temperature sensing unit) 72. The air flow meter detects the EGR gas flowing through the EGR pipes 16, 17. The air flow sensor detects the EGR gas flowing through the EGR pipes 16, 17. intake air temperature 71 detects the temperature of the intake air that is drawn into the combustion chamber of the engine E. The exhaust temperature sensor 72 detects the temperature of the exhaust gas. The exhaust temperature sensor 72 can detect the temperature of the recycled EGR gas to the intake pipe 15 from the EGR cooler module 1.

  The body 4 comprises the first and second seats 11, 12. The first seat 11 has inside the bypass passage (first through hole) 34. The second seat 12 has inside the coolant inlet passage (second passage hole) 43. The cooler inlet passage 42 is interposed between the first and second seats 11, 12. The first and second seats 11, 12 are spaced from each other by a predetermined distance . The axis of the first seat 11 is substantially perpendicular to the axis of the second seat 12. The first seat 11 consists of a first cylindrical member which is formed in one piece of a metallic material which has excellent properties of heat resistance and corrosion resistance, so as to have a substantially cylindrical shape. The metal material of the first seat 11 may be stainless steel such as SUS 304. The first seat 11 is formed separately from the body 4. The first seat 11 is snug-fitting into the wall surface of a first seat 11. communication passage which is between the reciprocal pipe portion 31 and the L-shaped pipe portion 32 in the body 4. The first communication passage is between the chiller inlet passage 42 and the passage of the Cooling outlet 53. The first seat 11 has an annular end surface in annular direction disposed on the side of the cooler inlet passage 42. The annular end surface of the first seat 11 defines the first seat 11. seat portion 91 on which the rear surface of the shutter 5 is applied. The first seat portion 91 performs the function of an adjusting member to define the range of movement of the shutter 5. The first seat portion 91 may be disposed on a horizontal line which is substantially perpendicular to the axis of the first seat 11. The rear surface of the shutter 5 is applied to the first seat portion 91 of the first seat 11, so that the shutter 5 can not rotate further in the direction in which the shutter 5 closes the seats. As shown in FIG. 2, the first seat portion 91 of the first seat 11 may have an annular projection which reduces the contact areas between the first seat portion 91 and the shutter 5. In this structure, the pressure to seal between the shutter 5 and the first seat 11 can be reinforced by means of the contact areas between them. The position of the shutter 5 corresponding to the complete closure of the bypass is defined by the position of the first seat portion 91, which is arranged axially on the side of the cooling inlet passage 42, relative to the first seat 11 The position of the shutter 5 corresponding to the complete closure of the bypass is located between the cooler inlet passage 42 of the first straight passage 31a and the cooler outlet passage 53 of the L-shaped passage 32a. A large diameter portion 94 is set on the opposite side to the small diameter portion (cylindrical portion) 93 of the first seat portion 91 of the first seat 11. The large diameter portion 94 is substantially snug and comes into contact with the partition wall 33 of the body 4. The large-diameter portion 94 is larger than the cylindrical portion 93, which is on the side of the first seat portion 91 in the first seat 11. The large-diameter portion 94 defines a part of larger diameter of the first seat 11.

  The second seat 12 is made of a second cylindrical member which is formed in one piece from a metallic material which has excellent heat resistance and corrosion resistance properties so as to have a substantially cylindrical shape. The metal material of the second seat 12 may be stainless steel such as SUS 304. The second seat 12 is formed separately from the body 4. The second seat 12 is clamped into the wall surface of the second communication passage; which is in the straight pipe portion 31. The second seat 12 has an annular end surface surface in the axial direction, located on the side of the first inlet port 41. The annular end surface of the second seat 12 defines the second seat portion 92 on which the front surface of the shutter 5 is applied. The second seat portion 92 performs the function of a regulating member for defining the range of movement of the shutter 5. The second seat portion 92 is inclined towards the first inlet port 41 with respect to a line perpendicular to the axis of the second seat 12. The second seat portion 92 is inclined by a predetermined angle, in a range such as 40 to 50, relative to the vertical line perpendicular to the axis of the second seat 12. The front surface of the shutter 5 is applied to the second seat portion 92 of the second seat 12, so that the shutter 5 can not rotate further in the direction in which the shutter 5 closes the inlet passages of the seat. Cooler 43, 44. The position of the shutter 5 corresponding to the cooler closure is defined by the position of the second seat portion 92, which is located axially on the side of the first inlet port 41. report u The second seat 12. The axis of the position of the shutter 5 corresponding to the complete closure of the cooler is on the axis of the first inlet port 41 of the body 4. The position of the shutter 5 corresponding to the closure The cooler assembly is opposite the first inlet port 41. A large diameter portion 96 is provided on the opposite side to the small diameter portion (cylindrical portion) 95 of the second seat portion 92 of the second seat 12. The large diameter 96 has substantially the shape of a collar and is in contact with the rectilinear pipe portion 31 of the body 4. The large diameter portion 96 is larger than the small diameter portion 95 which is on the side of the second part seat 92 in the second seat 12. The large diameter portion 96 defines a larger diameter portion of the second seat 12. Next, the operation of the exhaust gas recirculation apparatus will be described with reference to FIGS. 9. The engine E is started, which has the effect of opening an intake valve installed in the intake port. The intake port is defined in a cylinder head of the engine E. The intake air is filtered through the air filter 20, and the intake air is distributed into the intake manifold of each cylinder after have passed through the inlet pipe 15, a throttle body, and the equilibrium chamber. The distributed intake air is drawn into the combustion chamber of each cylinder of the engine E. The intake air is compressed in the engine, which has the effect of increasing the temperature sufficiently to burn the fuel. High pressure fuel is injected into the compressed air to burn the mixture of air and fuel. The combustion gas is exhausted from the combustion chamber of each cylinder of the engine E through the exhaust port defined in the cylinder head of the engine E. The exhaust gas is discharged through the exhaust manifold and the pipe 14. When the vacuum control valve and the electric vacuum pump are not supplied with electricity, the coil spring 68 biases the diaphragm 60 downwards in FIG. 9 into the actuator housings 64, 65. 9. The rod 61 of the actuator 9 moves downwards on the ends 3, 9. Referring to FIGS. 4, 5, it is noted that the rear surface of the shutter 5 is applied to the first part. seat 91 of the first seat 11. Therefore, the shutter 5 is in the fully closed position of the bypass, in which the shutter 5 opens the cooler inlet passages 43, 44 so that they are in the complete opening condition, and f erme branch passages 34; 35 so that they are in the condition of complete closure. The high temperature EGR gas, which is in a temperature range of 450 ° C. to 600 ° C., flows from the EGR pipe 16 to the cooler inlet passages 42 to 44 through the first inlet port 41. 4. Referring to FIGS. 2, 4, 5, it is noted that the high-temperature EGR gas passes straightly axially through the first straight passage 31a of the rectilinear pipe portion 31, and enters the EGR cooler. 2 through the first outlet 45 of the body 4. The high temperature EGR gas flows in the tubes of the EGR cooler 2, and exchanges heat with the cooling water, which is in a temperature range such as than 80 to 90 ° C as it passes through the tubes of the EGR cooler 2. Therefore, the high temperature EGR gas is cooled to become a low temperature EGR gas, which is in a temperature range in the vicinity of 100 C. EGR gas at low temperature again enters the body 4 through the second inlet 51 and the cooler outlet passage 52. The flow of the EGR gas is bent at about 90 in the cooler outlet passage 53, and out of the body 4 through the second outlet port 55. The low temperature EGR gas exiting the body 4 is recycled to the inlet pipe 15 through the EGR pipe 17. When the vacuum control valve and the electric vacuum pump are supplied with electricity, the shutter 5 is actuated to take the complete closed position of the cooler in the switching valve 3. The shutter 5 is applied to the second seat portion 92 of the second seat 12, so that the shutter 5 closes the cooler intake steps 43, 44. Vacuum is applied to the vacuum chamber 66 defined in the housings 64, 65 of the actuator 9. The diaphragm 60 moves upward on the Figure 9 in correspon- with the pressure difference between the vacuum chamber 66 and the atmospheric chamber 67. The rod 61 moves upwards in FIGS. 3, 9, so that the connecting plate 62 rotates about the axis of the shutter pin 6, in correspondence with the rectilinear movement of the rod 61 moving upwards in FIGS. 3, 9. The shutter pin 6 fixed to the connecting plate 62 rotates about its axis of rotation, as the connecting plate 62 rotates. The shutter 5 rotates about the shutter axis 6, so that the shutter 5 is lifted from the first seat portion 91 of the first seat 11 and is applied to the second seat portion 92 of the second seat 12. Therefore, the shutter 5 is in the complete closing position of the cooler, in which the shutter 5 is opposite to the first inlet port 41. When the shutter 5 is in the fully closed position of the cooler, the shutter 5 closes the cooler inlet passages 43, 44 and opens the bypass passages 34, 35. In this condition, the shutter 5 is held at an angle of rotation in a range such that 40 to 50 such that the shutter 5 closes the cooler inlet passage 43, and the shutter 5 opens the bypass passage 34. The high temperature EGR gas flows from the EGR pipe 16 to the inlet passage of the cooler 42 through the first inlet port 41 of the horn 4. Referring to FIGS. 2, 6, it is noted that the high temperature EGR gas passes rectilinearly through the cooler inlet passage 42, along the axis of the straight pipe portion 31, and abuts against the rear surface of the shutter 5 applied to the second seat portion 92 of the second seat 12. The shutter 5 is inclined by the angle of rotation (inclination angle) such as 40 to 50 by relative to the axis of the straight pipe portion 31. The flow direction of the high temperature EGR gas is changed to become the di-rection of the axes of the bypass passages 34, 35, by the collision against the rear surface of the shutter 5. The high temperature EGR gas passes straight through the bypass passages 34, 35, in the axis direction of the bypass passages 34, 35, and enters the cooler outlet passage 53 of the body 4. The EGR gas at high temperature comes out of the body 4 through the second gold Exit valve 55. The high temperature EGR gas exiting the body 4 is recycled to the inlet pipe 15 through the EGR pipe 17. Referring, for example, to FIGS. 2, 4, 5, it will be noted that shutter 5 is placed in the fully closed position of the bypass in a normal operating condition. The rear surface of the shutter 5 is applied to the first seat portion 91 of the first seat 11, which has the effect of closing the bypass passages 34, 35. The high temperature EGR gas is introduced into the cooler module EGR 1 through the EGR pipe 16, and the high temperature EGR gas is fully recycled in the inlet pipe 15 through the EGR cooler 2, so that the high temperature EGR gas is cooled sufficiently to through the EGR cooler 2 to become the EGR gas at low temperature. The low temperature EGR gas, which has a low density, is mixed in the intake air through the intake passage in the intake pipe 15. The combustion temperature of the fuel in the combustion chamber of each engine cylinder E is decreased, so that the emission of polluting substances such as NOx can effectively be reduced in the exhaust gas of the engine E, while the power of the engine is maintained. The engine E is in the normal operating condition after the lapse of a predetermined time following the starting of the engine E, for example. Referring to Figures 2, 6, it is noted that the shutter 5 is placed in the full closed position of the cooler in cold weather, for example. The front surface of the shutter 5 is applied to the second seat portion 92 of the second seat 12, so that the shutter 5 closes the cooler inlet passages 43, 44. The high temperature EGR gas is introduced into the EGR cooler module 1 through the EGR pipe 16, and the high temperature EGR gas is fully recycled to the inlet pipe 15 through the drift passages 34, 35, so that the high temperature EGR gas is recycled with a relatively high temperature. The intake air is sufficiently heated, so as to improve the combustion in the engine E. Therefore ,. It is possible to restrict the emission of hydrocarbons (HC) and smoke. by the engine E. The cold weather can be a condition in which the temperature of the EGR gas is lower than a predetermined temperature immediately after the start of the engine E. Alternatively, the cold weather may be a condition in which the atmospheric temperature is If the EGR gas is cooled and the temperature of the intake air is decreased, the emission of NOx can be reduced. However, when the engine speed is relatively low, and a low load is applied to the engine E, the hydrocarbon emission increases as a result of the cooling of the EGR gas. The shutter 5 is controlled to take an appropriate position (angle of rotation), in accordance with the operating condition of the engine E, so that the temperature of the EGR gas can be properly controlled, and the emissions of NOx and hydrocarbons can be reduced simultaneously.

  Referring to FIGS. 2, 4, 5, it will be noted that the position of the shutter 5 corresponding to the complete closure of the bypass is between the cooler inlet passages 42 to 44 defined in the rectilinear pipe portion 31 , and the cooler outlet passages 52, 53 defined in the L-shaped pipe portion 32, which is bent substantially at 90, in the body 4 of the EGR cooler module 1. The position of the shutter 5 corresponding to the complete closure of the bypass is defined by the position of the first seat portion 91. The constriction 56 is defined in the intermediate position through the cooler outlet passage 52 in the interior space of the L 32 of the body 4. The throat 56 has a section which is smaller than the section of the opening of the cooler outlet passage 52 on the side of the second inlet port 51. FIG. 4 represents the differential pressure 4P e the upstream side of the shutter 5 and the downstream side of the shutter 5 in the condition of complete closure of the shunt. The pressure in the vicinity of the front surface of the shutter 5 is equivalent to the exhaust pressure Pi of the EGR gas flowing from the EGR pipe 16 into the cooling inlet passage 42 through the first inlet port 41. The pressure in the vicinity of the rear surface of the shutter 5 is equivalent to the exhaust pressure Po of the EGR gas flowing from the cooler outlet passage 52 in the EGR pipe 17, through the cooler outlet passage 53 and the second outlet orifice 55 of the cooler module EGR 1. The pressure in the vicinity of the rear surface of the shutter 5, in particular the pressure in the bypass passages 34, 35 and the cooler outlet passage 53, is determined depending on the flow resistance (pressure drop, APc) of the EGR gas passing through the EGR cooler 2 and the flow resistance (pressure drop, APh) of the EGR gas passing through the throat 56 Pressio n in the vicinity of the rear surface of the shutter 5 is reduced by the differential pressure AP with respect to the exhaust pressure Pi. This relationship is defined by the following formula (1). AP = Pi - Po = APc + APh (1) The straight pipe portion 31 and the L-shaped pipe portion 32 have a region in which the exhaust pressure of the EGR gas is high adjacent to the front surface of the shutter 5, in particular in the cooler inlet passage 42. The straight pipe portion 31 and the L-shaped pipe portion 32 also have a region in which the exhaust gas pressure EGR is low at near the rear surface of the shutter 5, in particular in the bypass passages 34, 35 and the cooler outlet passage 53. When the shutter 5 is in the complete closure condition of the bypass, the differential pressure AP is applied to the shutter 5, so that the rear surface of the shutter 5 is applied to the first seat portion 91 of the first seat 11 by the pressure drop APc caused when the EGR gas passes through the EGR cooler 2, and the loss of e APh load caused when the EGR gas passes through the constriction 56. Referring to Figure 2, we note that the first seat portion 91 of the first seat 11 has the annular projection by means of which the contact areas between the first seat part 91 and the shutter 5 are reduced, so that the pressure to ensure the hermeticity between the shutter 5 and the first seat 11 can be reinforced by means of the contact areas between them. Therefore, it is possible to restrict the leakage of the EGR gas at high temperature from the cooler inlet passage 42 to the cooler outlet passage 52, through the bypass passages 34, 35, when the shutter 5 is in the fully closed position of the bypass. The leakage of the shutter 5 can be significantly reduced when the shutter 5 is in the complete closed position of the shunt.

  It is possible to avoid an increase in the temperature of the low temperature EGR gas, which is cooled by the cooling water passing through the EGR cooler 2. The temperature of the recycled EGR gas in the engine intake pipe E can be suitably decreased, so that the feed efficiency of the EGR gas entering the combustion chamber of each cylinder of the engine E can be improved. Therefore, the combustion temperature of the fuel in the combustion chamber of the engine E can be significantly reduced. As a result, the amount of NOx emitted by the engine E can be reduced, so that the amount of polluting substances in the exhaust gas emitted by the engine E can be significantly reduced. The cooled low temperature EGR gas in the EGR cooler 2 can be effectively recycled into the engine intake pipe E when the shutter 5 is in the full closed position of the bypass. There is no need to oversize the EGR cooler 2 and the EGR cooler module 1 in order to improve the cooling performance of the EGR gas. Therefore, the mounting space for installing the EGR cooler module 1 in an engine compartment can be reduced, and the mounting ability of the EGR cooler module 1 can be improved. Referring to Figures 2, 6, it is noted that when the shutter 5 is in the complete closed position of the cooler, the axis of the shutter 5 coincides substantially with the axis of the first inlet 41 of the body 4, i.e., the shutter 5 and the first inlet port 41 are substantially coaxial. The position of the shutter 5 corresponding to the complete closure of the cooler is opposed to the first inlet port 41 in the cooler inlet passages 42 to 44 of the pipe portion 31. The position of the shutter 5 corresponding the complete closure of the cooler is defined by the position of the second seat portion 92 of the second seat 12. The high temperature EGR gas enters the cooler inlet passage 42 through the first inlet port 41. When the shutter 5 is in the full closed position of the cooler, the high temperature EGR gas abuts against the rear surface of the shutter 5, so that the flow direction of the high EGR gas temperature is changed. The pressure (exhaust pressure) of the high temperature EGR gas entering the cooler inlet passage 42 through the first inlet port 41 is applied to the shutter 5 to apply the front surface of the shutter 5 on the second seat portion 92 of the second seat 12. Therefore, it is possible to restrict low temperature EGR gas leakage from the cooler inlet passages 42, 43 to the cooler outlet passage. 52, through the cooler EGR2, when the shutter 5 is in the complete closed position of the cooler.

  The leak of the shutter 5 can be significantly reduced when the shutter 5 is in the complete closed position of the cooler. It is possible to restrict a temperature decrease of the EGR gas at high temperature, under the action of the low temperature EGR cooled by the cooling water that passes through the EGR cooler 2. The high temperature EGR gas can be recycled efficiently in the intake pipe of the engine E, so that the intake air can be significantly warmed, and the combustion in the engine E can be improved. Therefore, the amount of NOx emitted by the engine E can be reduced, which can significantly reduce the amount of pollutants in the exhaust gas emitted by the engine E. Referring to Figures 7, 8, we note that the first rectilinear passage 31a, which is normally used in the operation of the motor E, has a substantially straight passage. The first rectilinear passage 31a does not have an abruptly bent portion, in which an inner passage is bent substantially at right angles. The first rectilinear passage 31a extends from the first inlet port 41 to the inlet of the EGR cooler 2 substantially in a straight line across the body 4. Referring to FIG. 4, it is noted that the EGR gas enters the cooler inlet passage 42 through the first inlet port 41, and flows substantially along the axis of the first straight passage 31a. The EGR gas smoothly enters the inlet of the EGR cooler 2 through the cooler inlet passages 42 to 44 and the first outlet port 45 without a right angle change in direction in the passage. Consequently, the pressure drop of the EGR gas flow can be significantly reduced when the EGR gas is recycled in the engine intake pipe E through the EGR cooler 2. It is possible to reduce the pressure drop in the flow of EGR gas passing through the cooler inlet passages 42 to 44 and the first outlet port 45 of the first straight passage 31a, which is normally used in the operation of the engine E. The amount of EGR gas entering the chamber combustion of each cylinder of the engine E can be increased. The combustion temperature of the fuel in the combustion chamber of the engine E can be effectively reduced, which makes it possible to reduce the emission of substances such as NOx into the exhaust gas emitted by the engine E. Referring to FIGS. , 8, it is noted that the bypass passages 34, 35 are defined in the body 4 which communicates with the inlet and the outlet of the EGR cooler 2. The bypass passages 34, 35 define the shortcut between the first rectilinear passage 31a and the passage in the form of L 32a. The cooler inlet passages 42 to 44 communicate by a shortcut with the cooler outlet passages 52, 53, so that the EGR gas can be recycled to the engine intake pipe E without passing through the EGR cooler. 2. The bypass passages 34, 35 are substantially perpendicular to the axis of the first rectilinear passage 31a. Referring to FIG. 22, it is noted that the switch valve 1102 disclosed in EP 0987427 has the structure in which the cooler inlet passage 1104, the cooler outlet passage 1105 and the bypass passage 1106 are in parallel. In this embodiment, the body 4 of the switching valve 3 can have reduced dimensions in comparison with the structure of the switching valve 1102 in the document EP 0987427 shown in FIG. 22. Therefore, i. It is possible to reduce the necessary mounting space in an engine compartment for the EGR cooler module 1, which includes the EGR cooler 2 and the switch valve 3, which reduces the dimensions of the cooler module 1. L The mounting ability of the EGR cooler module 1 can thus be improved. When the shutter 5 is in the full open position of the bypass, the shutter 5 is applied to the second seat 12 which defines the position of the shutter 5 corresponding to the complete closure of the cooler. In this condition of complete opening of the bypass, the second seat 12 is inclined so that the normal to the rear surface of the shutter 5 is inclined by a predetermined angle, in a range such as 40 to 50, relative to at the vertical line perpendicular to the axis of the first rectilinear passage 31a (cooler inlet passages 42 to 44) of the body 4, to the inlet port 41. In other words, in this complete opening condition from the shunt, the normal to the rear surface of the shutter 5 is inclined forward towards the inlet port 41 by a predetermined angle in a range such as 40 to 50. In the above structure, an abruptly bent portion, in which the EGR gas flow is bent perpendicularly and abruptly, can be avoided in an interior bypass space including the cooler inlet passage 42, the bypass passages 34, 35, the cooler outlet passage 53 and the second outlet port 55. This bypass interior space is temporarily used only for a limited period, such as immediately after engine start E and when the temperature EGR gas (exhaust gas) is below a predetermined temperature. The EGR gas enters the cooler inlet passage 42 through the first inlet port 41 and passes rectilinearly substantially along the axis of the first straight passage 31a. Then, the EGR gas flows along the inclined rear surface of the shutter 5, while changing at right angles its direction of flow. The EGR gas thus smoothly enters the bypass passages 34, 35. The bypass passages 34, 35 and the cooler outlet passage 53 constitute the second straight passage which extends from the branch portion (flow passage). cooled inlet (42), substantially rectilinearly to the second outlet port 55.

  The EGR gas flows from the bypass passages 34, 35 into the cooler outlet passage 53, and passes axially along the second straight passage. The EGR gas exits the second exit port 55 without changing direction at right angles through the second straight passage. The flow of EGR gas that enters the first straight passage 31a through the first inlet port 41 can be improved in comparison with the flow of EGR gas that enters the bypass passages 34, 35 after changing direction abruptly and at a right angle immediately before the bypass passages 34, 35. Therefore, the pressure drop of the EGR gas flow can be significantly reduced when the EGR gas is recycled to the inlet pipe of the Motor E after bypassing the EGR cooler 2. Therefore, the pressure drop of the EGR gas flow, which passes through the bypass passages 34, 35 for the limited time during the operation of the engine E, can be reduced. The heating effect of the intake air sucked into the combustion chamber of the engine E can be improved, which improves the combustion condition of the combustion chamber. Therefore, it is possible to significantly reduce the amount of polluting substances such as HC in the exhaust gas emitted by the engine E.

  The axial length of the shutter seat 11 (cylindrical member 11) can define the length of the bypass passage. The length of the bypass passage may be the length equal to the total of the axial length of the shutter seat 11 (cylindrical member 11) and the length of the through hole in the body 4.

  Second Embodiment As shown in FIGS. 10 to 12, the body 4 includes the partition wall 33 which separates the straight pipe portion 31 from the L-shaped pipe portion 32. An annular space 30 is defined by forming a recessed portion in the partition wall 33.

  The annular space 30 surrounds the opening of the straight pipe portion 31. The first and second seats 11, 12 are respectively clampingly fitted into the wall surfaces of the straight pipe portion 31 and the The end surface, in the axial direction, of the first seat 11 is on the upstream side of the EGR gas flow. The axial end surface of the first seat 11 defines the first substantially annular seat portion 91. The rear surface of a shutter 205, which defines a first closure surface 291, is adapted to be applied to the first seat portion 91. The first seat portion 91 serves as an opening periphery bypass passages 34, 35. The first seat portion 91 performs the function of an adjusting member to define the range of movement of the shutter 205. The first sealing surface 291 on the rear surface of the shutter 205 is applied to the first seat portion 91, the first seat 11, so that the shutter 205 can not rotate further in the direction in which the shutter 205 closes the bypass passages 34, 35. The first part of seat 91 of the first seat 11 may have an annular projection to reduce the contact areas between the first seat portion 91 and the shutter 205, similarly to the first embodiment. In this structure, a pressure to ensure the hermeticity between the sealing surface 291 of the shutter 205 and the sealing surface of the first seat 11, can be enhanced by the contact areas therebetween. The annular space 30 is between the outer circumferential periphery of the first seat portion 91 of the first seat 11, and a passage surface of the partition wall 33. The annular space 30 circumferentially surrounds the periphery of the first seat portion 91. The axially end surface of the second seat 12 is on the upstream side of the EGR gas flow. The axially end surface of the second seat 12 defines the second annular seat portion 92. The front surface of the shutter 205, which defines a second closure surface 292, is adapted to be applied to the second portion of the seat. seat 92. The second seat portion 92 fulfills the function (2) of an opening periphery of the cooler inlet passages 43, 44. The second seat portion 92 serves as an adjuster to define the range of motion of the shutter 205. The second shutter surface 292 on the front surface of the shutter-205 is applied to the second seat portion 92 of the second seat 12, so that the shutter 205 can not rotate further in the direction in which shutter 205 closes cooler inlet passages 43, 44. The first inlet port 41 defines an opening in the upstream end of body 4, relative to at the flow of the gas call. The second outlet port 55 defines an opening in the downstream end of the body 4, with respect to the exhaust gas flow. The first inlet port 41 is connected to the opening end of the EGR pipe 16 on the downstream side of the EGR gas flow. The second outlet port 55 is connected to the opening end of the EGR pipe 17 on the upstream side of the EGR gas flow.

  The outer wall of the body 4 and the partition wall 33 define the cooler communication passage and the bypass communication passage in relation to the first inlet port 41. The cooler communication passage includes the passage of cooler inlet 31a, which communicates with the inlet of the EGR cooler 2, and the cooler outlet passage 32a which communicates with the outlet of the EGR cooler 2. The cooler communication passage defines an exhaust path. The EGR gas entering the first inlet port 41 passes through the coolant communicating passage and the EGR cooler 2 so that the EGR gas is recycled to the engine E intake system. cooler inlet 31a is the first straight passage 31a which extends rectilinearly from the first inlet port 41 to the inlet of the EGR cooler 2. The cooler inlet passage 31a is substantially perpendicular to the axis The coolant inlet passage 31a includes the cooler inlet passageway 42, a coolant through hole 43a, and the first outlet port 45. The cooler outlet passageway 32a is the L-shaped passage 32a which extends from the outlet of the EGR cooler 2 and is bent substantially at right angles to the second outlet port 55. The cooler outlet passage 32a includes the second inlet port 51 e The cooler passage holes 43a are formed in the second seat 12. The first outlet port 45 communicates with the inlet ends of the EGR cooler tubes 2. The second port of inlet 51 communicates with the outlet ends of the EGR cooler tubes 2. The bypass communication passageway includes a bypass passage hole 34a and the bypass passage 35 through which the coolant inlet passage 31a communicates with the passageway. cooler output 32a. The bypass passage hole 34a and the bypass passage 35 define a shortcut between the cooler inlet passageway 31a and the cooler outlet passage 32a. The bypass communication passage includes the cooler inlet passage 42, the bypass passage hole 34a, the bypass passage 35 and the cooler outlet passage 53. The bypass communication passage constitutes the a second straight passage extending from the cooler inlet passageway 42 to the second outlet port 55 substantially rectilinearly along the bypass passageway 34a and the bypass passageway. bypass 34a defines a first through hole in the first seat 11. The bypass passage hole 34a forms a branch from the cooler inlet passage 31a. The partition wall 33 is formed in one piece with the interior space of the body 4. The partition wall 33 hermetically separates the coolant inlet passage 31a from the cooler outlet passage 32a. An axis hole 46 is formed in the partition wall 33. The axis hole 46 extends in the axial direction of the shutter axis 6. A cylindrical bearing is installed in the pin hole 46 for rotatably supporting the shutter shaft 6 by means of a bearing component (not shown), such as a bushing. The shutter pin 6 can rotate in the partition wall 33 through the bearing. The outer wall of the body 4 of a first side, in the axial direction, of the partition wall 33, has an opening of the first side in the axial direction of the axis hole 46. The plug 37 is adjusted with tightening on the body 4 hermetically sealing the opening of the pin hole 46. A sealing component (not shown), such as a. gas seal, is placed between the inner circumferential periphery of the shaft hole 46 of the partition wall 33 and the outer circumferential periphery of the shutter shaft 6, in addition to the bearing component such as a socket. The seal for gases is a cylindrical member which is for example formed in one piece of an elastomer such as rubber. The gas seal fulfills the function of a sealing member which opposes the entry of foreign bodies contained in the EGR gas into the space between the bearing defined in the pin hole 46 and the shutter pin 6. The partition wall 33 surrounds the periphery of the shutter pin 6 in such a manner that the partition wall 33 protects the shutter pin 6 against the high-EGR gas temperature and EGR gas at low temperature. Therefore, the partition wall 33 protects the shutter shaft 6, the bearing which supports the shutter shaft 6 and the seal for the gases, which is mounted on the shutter axis 6, against the heat of the EGR gas at high temperature. The partition wall 33 also protects the shutter shaft 6 and the bearing against an adhesive substance such as adhesive carbon contained in the low temperature EGR gas. The switching valve 3 comprises the shutter 205, the shutter shaft 6 and the shutter lever 7. As shown in FIGS. 13, 14, the shutter actuator device comprises the electric vacuum pump. (Not shown), the vacuum control valve (not shown) and the actuator 9. The shutter actuator device actuates the shutter 205 by moving the diaphragm 60. The electric vacuum pump performs the function of a source depression which is actuated by an electric motor. The vacuum control valve is installed in an intermediate position in the air passage pipe communicating with the air inlet port of the electric vacuum pump. The vacuum control valve may be actuated by a solenoid actuator or an electric motor. The actuator 9 generates an axial force by applying a vacuum from the electric vacuum pump via the vacuum control valve. The actuator 9 comprises the rod 61, a support 153, a diaphragm seat 154. and the housings 64, 65. The rod 61 is axially movable together with the diaphragm 60. The carrier 153 is a substantially cylindrical member having a communication hole with the atmosphere 152, which extends through the actuator 9. The The diaphragm seat 154 is placed on the upper end of the support 153 in FIG. 14. The diaphragm 60 and the coil spring 68 can move elastically in the housings 64, 65. The diaphragm 60 is an elastic material consisting of of a rubber-like material. The diaphragm 60 is interposed between flanges of the housings 64, 65, and then the outer circumferential periphery of the housing 65 is bent to a U-shape, in section. Therefore, the outer circumferential periphery of the diaphragm 60 is fixed between the flanges of the housings 64, 65.

  The housings 64, 65 define inside an interior space (diaphragm chamber). The diaphragm chamber is hermetically sealed by the diaphragm 60 between the vacuum chamber 66 and the atmospheric chamber 67. The vacuum chamber 66 communicates with an air inlet of the vacuum pump through the vacuum control valve. The atmospheric chamber 67 communicates with the atmosphere through the communication hole with the atmosphere 152. An axial end of the rod 61 is curved so as to have an L shape. This L-shaped axial end of the rod 61 is engaged in a coupling hole of the connecting plate 62. The diaphragm 60 is interposed between plates 164, 165. The other axial end of the rod 61 is on the upper side in FIG. Another axial end of the rod 61 is connected to the diaphragm 60 through the plates 164, 165, while being coupled to a central hole of the diaphragm 60. The connecting plate 62 serves the function of a motion transformation element which converts a rectilinear movement of the rod 61 into a rotational movement of the shutter shaft 6. The connecting plate 62 constitutes a transmission mechanism in association with the shutter axis 6 and the rod 61. The plate link 62 has a outlet end having a coupling hole in which is fixed an axial end of the shutter axis 6. The axial end of the shutter shaft 6 projects outwardly from the plug 37. actuator 9 comprises support 153 which is fixed to a tray-shaped seat of bracket 63 (FIG. 13), so that su.pp and 153 support actuator 9. Helical spring 68 serves the purpose of a biasing member which applies a biasing force to the diaphragm 60 in a direction in which the coil spring 68 urges the shutter 205 toward the first seat portion 91 of the first seat 11 to close the bypass hole 34a. The coil spring 68 urges the shutter 205 in the closing direction. An axial end of the coil spring 68 is supported by a spring seat 166 on the diaphragm 60 side. The other axial end of the coil spring 68 is supported by a ceiling portion of the housing 64, away from the diaphragm 60. The housing 64 is connected to the vacuum pipe 69 through which a vacuum is applied in the vacuum chamber 66 from the electric vacuum pump and the vacuum control valve. The upper end of the diaphragm seat 154 in FIG. 14 fulfills the function of an adjusting member (stop). The upper end of the diaphragm seat 154 sets the diaphragm 60 to a default position when the diaphragm 60 is moved to the underside in Fig. 14, by the biasing force of the coil spring 68, in a condition in which the vacuum applied in the actuator 9 from the vacuum pump is removed. In this structure, the diaphragm seat 154 prevents further movement of the diaphragm 60 when the rear surface of the diaphragm 60 comes into contact with the diaphragm seat 154. In this condition, the diaphragm 60 is in the default position. A plug 169 closes the opening of the ceiling portion of the housing 64. The plug 169 serves as a stop which adjusts the travel of the diaphragm 60. The lower axial end of the plug 169 in FIG. an adjusting member (stop). The lower axial end of the plug 169 regulates the displacement (full lift position, complete lift) of the diaphragm 60 when a depression is applied in the actuator 9 from the vacuum pump, so that the diaphragm 60 moves upwards in FIG. 14 in correspondence with a pressure difference between the vacuum chamber 66 and the atmospheric chamber 67. In this structure, the stopper 169 prevents the diaphragm 60 from moving further when Before the diaphragm 60 comes into contact with the stopper 169. In this condition, the diaphragm 60 is in the full lift position. The actuator 9 is adapted to overcome the resultant of both the biasing force of the coil spring 68 and an external force such as vibration and pressure applied by the motor E when the shutter 205 is open, of That the actuator 9 is capable of actuating the shutter 205. The actuator 9 generates an axial force which is related to the diameter of the diaphragm 60 and the depression applied to the diaphragm 60. The axial force generated by the actuator 9 is designed to be greater than the resultant of both the external force (motor force) applied by the motor E, and the biasing force (elastic force) of the coil spring 68. The actuator 9 moves the diaphragm 60 in the direction of the thickness of the diaphragm 60, upwards in FIG. 14, against the elastic force of the coil spring 68, which has the effect of moving the rod 61 together with the diaphragm 60, using a pressure difference between the vacuum chamber 66 and the atmospheric chamber 67. The rod 61 moves axially upwards in FIG. 14, and the movement of the rod 61 is transmitted to the shutter axis 6 by via the connecting plate 62, so that the shutter axis 6 rotates at a predetermined angle θ, such as 40 to 50. Therefore, the shutter 205 is actuated between the complete closure position of the bypass and the complete closed position of the cooler, in the three-way valve and two positions. The vacuum control valve controls the vacuum applied in the vacuum chamber 66. The shutter 205 is made of a metallic material which has excellent heat resistance and corrosion resistance properties, which has been given a predetermined curved shape. Specifically, the shutter 205 is formed by pressing a flat metal plate, placed on a die, to enter a hole in the die using a punch which is smaller than the outer diameter of the die. As a result, the shutter 205 is press-formed, by deep drawing, for example, so as to be a body having a bottom. Referring to FIGS. 10, 11 and 15, it will be noted that the shutter .2.O5 has an end surface defining the first obturating surface 291 which closes and opens the bypass passage hole 34a while being applied to the first seat 11 and lifted from it. The first sealing surface 291 fulfills the function of a sealing surface. The first sealing surface 291 is placed on the rear surface, which is opposite to the front surface of the shutter 205. Referring to FIGS. 11, 12 and 15, it is noted that the shutter 205 includes the end surface in the direction of the thickness of the shutter 205. The other end surface of the shutter 205 defines the second closure surface 292 which closes and opens the cooler passage hole. 43a being applied to the second seat 12 and raised thereof. The first and second closure surfaces 291, 292 of the shutter 205 are substantially circular planar surfaces.

  The shutter 205 is actuated between the complete closure position of the bypass and the complete closed position of the cooler. The complete closure position of the bypass is the default position in which the operating angle 8 of the shutter 205 is 0, as seen in FIG. 10. The complete closed position of the cooler is the position of complete lifting in which the operating angle 0 of the shutter 205 is the predetermined angle of 40 to 50, as shown in Figure 12. The first sealing surface 291 on the rear surface side of the shutter 205 is applied and fitted to the first seat 11 in the fully closed position of the bypass, so that the bypass hole 34a is closed, and the cooler passage hole 43a is open. The second closure surface 292 on the front surface side of the shutter 205 is applied and fitted to the second seat 12 in the complete closed position of the cooler, so that the cooler passage hole 43a is closed, and that the bypass passage hole 34a is open. Referring to FIGS. 10, 15, it will be noted that when shutter 205 is in the fully closed position of the bypass, robber 205 is positioned so that the axial direction of an average flow of EGR gas passing through the cooler inlet passage 42 is substantially parallel to the vertical direction perpendicular to the axis of shutter 205 ... insi, the average flow of EGR gas passing through the cooler inlet passage 42 is substantially perpendicular to the 205. In this condition, the vertical direction perpendicular to the shutter axis 205 is substantially parallel to the first and second shutter surfaces 291, 292. The shutter 205 has a circumferential flap 293 to generate a lifting force. The circumferential flap 293 is formed by bending the outer circumferential periphery which is the radially outer side of the first closure surface 291 in the shutter 205. The circumferential flap 293 is formed by bending the outer circumferential periphery to the outer circumferential periphery. first obturating surface, downwards in FIG. 15, at a predetermined angle. The circumferential periphery of the shutter 205 is bent so that the circumferential flap 293 enters the annulus 30 when the shutter 205 is in the fully closed position of the shunt. Thus, the circumferential flap 293 is at least partially placed in the annular space 30 when the shutter 205 is in the fully closed position of the shunt. The circumferential flap 293 is formed over the entire circumferential periphery of the shutter 205 in the circumferential direction of the shutter 205. Referring to Fig. 15, it is noted that when the actuator 9 actuates the shutter 205 towards the complete closed position of the cooler, from the fully closed position of the bypass, a lifting force is applied to the shutter 205 as an operating assisting force, in a direction in which the operation of the shutter 205 is assisted. The shutter pin 6 is formed in one piece of a metallic material which exhibits excellent heat resistance and corrosion resistance properties. The metallic material of the shutter pin 6 may be stainless steel such as SUS 304. The shutter pin 6 can slide along the inner circumferential periphery, which defines the pin hole 46 of the partition wall 33, through the bearing component and the sealing member. The fixed portion 74 is a cylindrical member. The stationary portion 74 is attached to the outer circumferential periphery of the shutter shaft 6 to support the fixed end of the shutter lever 7. The shutter shaft 6 has an axial end projecting outwardly. of the body 4 through the plug 37. The shutter lever 7 has a fixed end which is fixed to the outer periphery of the fixed portion 74 of the shutter shaft 6, by welding or the like. The other end of the shutter lever 7 is a free end attached to the first sealing surface 291 on the side of the rear surface of the shutter 205, the lower side in FIG. 15. The fixed end The shutter lever 7 has a substantially arcuate shape or a cylindrical shape corresponding to the shape of the fixed portion 74. The fixed end of the shutter lever 7 is fixed on a part of the outer periphery of the part. fixed 74, by welding or others. The free end of the shutter lever 7 has a shape corresponding to a hole, or the like, defined in the center of the shutter 205. The free end of the shutter lever 7 is fixed at the center of the first surface of the shutter. sealing 291 on the rear surface side of the shutter 205, by welding or the like. The shutter 205 is a shutter member which rotates about the fixed end of the shutter lever 7. The shutter 205 selectively opens one of the cooler passage hole 43a and the bypass passage hole. 34a, and closes the other of the cooler passage hole 43a and bypass passage hole 34a, on the free end side of the shutter lever 7. Next, the operation of the gas reclaimer will be described. exhaust.

  The flue gas is exhausted from the combustion chamber through the exhaust port formed in the cylinder head of the engine E. The exhaust gas is exhausted through the exhaust manifold and the exhaust pipe 14. When the vacuum control valve and the vacuum pump are not supplied with electricity, the diaphragm 60 is biased against the diaphragm seat 154 by the biasing force of the coil spring 68 housed in the housings 64, 65 of the actuator 9, so that the rod 61 of the actuator 9 is moved downwards in Figure 14. Referring to Figure 10, we note that the first closure surface 291 of the shutter 205 is maintained on the first seat portion 91 of the first seat 11 when the shutter 205 is held in the fully closed position of the bypass, wherein the shutter 205 closes the bypass hole 34a, while the through hole refro lover 43a is open.

  The high temperature EGR gas flows from the EGR pipe 16 to enter the cooler inlet passage 42 through the first inlet port 41 of the body 4. Referring to FIG. the high temperature EGR gas passes rectilinearly through the cooler passage hole 43a and the first outlet port 45, and enters the EGR cooler 2 through the first outlet port 45. The high temperature EGR gas exchanges the heat with the cooling water as it passes through the tubes in the EGR cooler 2, so that the high temperature EGR gas becomes the EGR gas at a low temperature. The low temperature EGR gas enters the body 4 again through the second inlet port 51 and the cooler outlet passage 52. The flow of the EGR gas is bent about 90 in the exit passage of the cooler 53, and exits the body 4 through the second outlet port 55. The low temperature EGR gas flowing out of the body 4 is recycled to the inlet pipe 15 through the EGR pipe 17. When the vacuum control valve and the vacuum pump are supplied with electricity, the shutter 205 is applied to the second seat portion 92 of the second seat 12, so that the shutter 205 closes the cooler passage hole 43a. . The evacuation port 1'0 of the vacuum pump generates a positive pressure and the inlet port of the vacuum pump generates a vacuum when it is supplied with electricity, so that the vacuum pump sucks air from the vacuum chamber 66, through the air passage. The vacuum chamber 66 receives a vacuum, so that a pressure difference is produced between the vacuum chamber 66 and the atmospheric chamber 67, which communicates with the atmosphere. The diaphragm 60 moves upwards in FIG. 14, against the biasing force of the coil spring 68, according to the pressure difference between the vacuum chamber 66 and the atmospheric chamber 67, so that the rod 61 moves axially. The connecting plate 62 rotates about the axial direction of the shutter axis 6, in correspondence with the rectilinear movement of the rod 61 which is displaced upwards in FIG. 14, so that the axis d shutter-6 attached to the connecting plate 62 rotates about the center of rotation as the connecting plate 62 rotates. The shutter 205 rotates about the shutter axis 6, so that the shutter 205 is lifted from the first seat portion 91 of the first seat 11, and is applied to the second seat portion 92 of the second seat 12. The shutter 205 is in the fully closed position of the cooler, wherein the shutter 205 opens the bypass hole 34a and the bypass passage 35, and closes the cooler passage hole 43a. The high temperature EGR gas from the EGR pipe 16 enters the cooler inlet passage 42 through the first inlet port 41 of the body 4. Referring to FIG. high temperature passes axially, rectilinearly, along the cooler inlet passage 42, and collides with the first seat surface 291 on the rear surface side of the shutter 205 which is applied to the second portion of seat 92 of the second seat 12. In this condition, the first sealing surface 291 on the rear surface side of the shutter 205 is inclined by an angle which is in a range such that 40 to 50, relative to the axial direction of the rectilinear passage. The flow of high temperature EGR gas colliding with the first closure surface 291 changes direction of flow, to move toward the axial directions of the bypass passage hole 34a and the bypass passage 35. The high temperature EGR gas passes through the bypass hole 34a and the bypass passage 35, and flows in the direction of the axes of the bypass hole 34a and the bypass passage 35. The high temperature EGR gas enters the cooler outlet passage 53 and flows out of the body 4 through the second outlet port 55. The high temperature EGR gas flowing out of the body 4 is recycled into the inlet pipe 15 through the EGR pipe 17. Referring to FIG. 10, it is noted that the shutter 205 is in the complete closed position of the bypass, so that the first shutter surface 291 is applied to the first part of the shutter. 91. The EGR gas entering the EGR cooler module 1 through the EGR pipe 16 is fully recycled into the inlet pipe 15 through the. EGR cooler 2, which causes the high temperature gas to cool sufficiently through the EGR cooler 2. The low temperature EGR gas, which has a low density, is mixed in the intake air through the passage In the intake pipe 15. The combustion temperature of the fuel in the combustion chamber of the engine E can be effectively reduced, so that emissions of substances such as NOx can be reduced in the exhaust gas. emitted by the motor E. Referring to Figure 12, it is noted that the shutter 205 is placed in the full closed position of the cooler in cold weather, for example. The second closure surface 292 on the front side of the shutter 205 is applied to the second seat portion 92 of the second seat 12, so that the shutter 205 closes the cooler passage hole 43a. The EGR gas is introduced into the EGR cooler module 1 through the EGR pipe 16, and the EGR gas is fully recycled to the inlet pipe 15 through the bypass hole 34a and the bypass passage 35. , so that the EGR gas is recycled with a relatively high temperature. The intake air is sufficiently heated to improve the combustion in the engine E. Therefore, it is possible to restrict the emission by the engine E of polluting substances such as hydrocarbons (HC) and smoke .

  The emission of NOx can be reduced by cooling the EGR gas and decreasing the temperature of the intake air. However, when the rotation speed and the load of the engine E are relatively low, the emission of HC is increased by the cooling of the EGR gas. The temperature of the EGR gas can be properly controlled by adjusting the position of the shutter 205 at the appropriate angle 9, in accordance with the operation of the engine E, so that the emission of NOx and HC can be reduced simultaneously. When the shutter 205 is in the fully closed position of the bypass, a differential pressure is created between the first and second shutter surfaces 291, 292 of the shutter 205 by the pressure drop of the EGR gas passing through the shutter 205. EGR cooler 2. The differential pressure is applied to shutter 205 so that the first sealing surface 291 is biased against the first seat portion 91 of the first seat 11, which has the effect of improving the hermetic shutter performance 205 when the shutter 205 is in the fully closed position of the shunt. As a result, the leakage is significantly reduced when the shutter 205 is in the fully closed position of the shunt. In this structure, the actuator 9 may need to produce a high force to actuate the shutter axis 6. Therefore, the diaphragm 60 diameter may need to be enlarged. However, the enlargement of the diaphragm 60 can lead to an increase in the dimensions of the actuator 9. Referring to FIG. 16, it is noted that in this second embodiment, the resultant is applied to the shutter 205. This result is a resultant load of the external force applied by the motor E and the biasing force applied by the coil spring 68. In this second embodiment, a fluidic force a2 is applied to the shutter 205. Therefore, the shutter 205 receives the resultant a1, which is the resultant load of the resultant y and the fluidic force a2. In this second embodiment, the actuator 9 must generate the required actuation force, which is greater than a2 + y. On the contrary, in the first embodiment, the resultant is applied to the shutter 5, similarly to the second embodiment. However, in the first embodiment, a fluidic force [32, which is greater than the fluidic force a2 is applied to the shutter 5. The shutter 5 receives the resultant force (31, which is the resulting load of the resultant y and the fluidic force f 32. In the first embodiment, the actuator 9 must generate a required actuation force 13, which is greater than pi + y.This relation is defined by the formula (2) actuation force required external force + biasing force + fluidic force (2) In particular, the fluidic force to the shutter 5, 205 may be a positive force or a negative force depending on the direction of the EGR flow and the direction of operation of the actuator 9. When the fluidic force is applied to the shutter 5, 205 as a positive force, the fluidic rust is applied to the shutter 5, 205 as a opposite charge to the operating direction of 5, 205. On the contrary, when the fluidic force is applied to the actuator 5, 205 as a negative force, the fluidic force is applied to the actuator 5, 205 as an assist force. in the operating direction of the shutter 5, 205. A depression applied to the vacuum chamber 66 of the actuator 9 may decrease depending on the engine system or in high altitude use. Even when the depression applied to the vacuum chamber 66 decreases, it is necessary to have a smooth operation of the shutter 5, 205, without increasing the dimensions of the actuator 9. When the vacuum applied to the vacuum chamber As the pressure 66 decreases, the actuating force of the actuator 9 decreases. When the diaphragm 60 is enlarged, the dimensions of the actuator 9 are increased. Therefore, in this second embodiment, the curved shutter 205 is adopted instead of the plate-shaped shutter 5 to avoid increasing the dimensions of the plate. the actuator 9. Specifically, the circumferential periphery of the shutter 205 is curved toward the first closure surface 291, so that the circumferential flap 293 is formed around the entire circumferential periphery of the shutter 205 In this structure, the shutter 205 has the curved shape over the entire circumferential periphery of the shutter 205, to produce a lifting force. In a bypass opening operation, a depression is applied to the vacuum chamber 66 of the actuator 9, so that the shutter 205 is actuated to move from the complete closure position of the branch to the closed position complete cooler. The EGR gas flow enters the cooler inlet passage 42 through the first inlet port 41. In the bypass opening operation, the velocity of the EGR gas flow passing along the the front surface of the shutter 205, and the velocity of the gas flow EGR passing along the rear surface of the shutter 205, are mutually different, unlike the first embodiment in which the obiter 5 has the substantially flat shape. The circumferential periphery of the shutter 205 is curved toward the first obturating surface 291 on the rear surface side of the shutter 205. Referring to FIG. the flow of EGR gas passing along the second sealing surface 292 on the front surface side of the shutter 205 is greater than the speed of the EGR gas flow flowing along the first shutter surface 291 on the rear surface side of the shutter 205. Referring to FIGS. 11, 15, it is noted that a pressure difference is created between the second shutter surface 292 and the first surface of the shutter shutter 291, which has the effect of creating the lifting force which is applied to the shutter 205 in the direction in which the shutter 205 is lifted from the first seat portion 91 of the first seat 11. The force of uplift is applied to the shutter 205 in the di-rec actuating the shutter 205 in the bypass opening operation. The lifting force is applied to the shutter 205 to assist the actuating force of the bypass opening operation.

  The velocity of the EGR gas flow that passes along the front surface of the shutter 205 is greater than the velocity of the EGR gas flow that passes along the rear surface of the shutter 205. The circumferential periphery of the shutter 205 is curved towards the first sealing surface 291, so that the difference between the speeds of the EGR gas flows is even greater. Referring to FIG. 15, it is noted that the pressure is low in the vicinity of the surface for which the speed of the EGR gas flow is high. The pressure is high in the vicinity of the surface for which the speed of the gas flow EGR is low. The pressure on the front surface side of the shutter 205 is less than the pressure on the rear surface side of the shutter 205. The pressure difference is applied to the shutter 205. Therefore, the shutter 205 is raised by the lifting force, acting on the rear surface of the shutter 205. In particular, the circumferential periphery of the shutter 205 is curved towards the first sealing surface 291, which has the effect of reinforcing the lifting force to assist the bypass opening operation. The depression applied to the vacuum chamber 66 of the aircon 9 may decrease depending on the engine system or in high altitude use. In this case, the pressure difference between the vacuum chamber 66 and the atmospheric chamber 67 may become small. Therefore, the actuating force of the rod 61 of the actuator 9 may decrease. Even in this case, in this second embodiment, the actuation force required for the shutter release operation 205 of the shutter 205 can be reduced from f3 to a. This reduction in the required actuation force is also effective for improving the shutter performance of the shutter 205. In this second embodiment, the shutter 205, which has the curved shape, receives the resulting load al = y + a2. This resultant charge α1 is the resultant of the fluidic force a2, the external force and the biasing force. In contrast, in the first embodiment, the shutter 5, which is substantially flat in shape, receives the resulting charge 61 = y + R2. This resulting load (31 is the resultant of the fluidic force (32, the external force and the biasing force.

  Referring to Fig. 16, it is noted that the actuating force 13 required for the shutter bypass opening operation 205 in this second embodiment can be reduced by the difference X32 - a2, in comparison with the actuating force required for the shutter bypass opening operation 5 in this first embodiment. Consequently, the shutter 205 can be actuated in a regular manner using the actuator 9, without increasing the diameter of the diaphragm 60. It is possible to avoid having to increase the dimensions of the EGR cooler module 1 including the Actuator 9. As a result, a mounting space for the EGR cooler module 1 can be easily obtained in a vehicle such as an automobile. As a result, the mounting ability of the EGR cooler module 1 can be improved. The bypass hole 34a is substantially perpendicular to the flow of EGR gas passing through the cooler inlet passage 31a and the cooler inlet passage 42. The first closure surface 291 of the shutter 205 is substantially parallel to the direction of the EGR gas flow passing through the cooler inlet passage 31a, when the first closure surface 291 of the shutter 205 is applied to the first seat portion 91 of the first seat 11. The difference Between the speed of the EGR gas flow passing along the front surface of the shutter 205 and the velocity of the EGR gas flow passing along the rear surface of the shutter 205 further increases. As a result, the pressure difference applied to the front surface and the rear surface of the shutter 205 increases further. As a result, the lifting force (assisting force) applied to the shutter 205 in the bypass opening operation can be further increased. The circumferential periphery of the shutter 205 is bent so that the circumferential flap 293 penetrates inside the annular space 30 when the shutter 205 is in the complete closed position of the bypass. Thus, the circumferential flap 293 is at least partially housed in the annular space 30 when the shutter 205 is in the fully closed position of the shunt. In this structure, the EGR gas flow enters hardly between the passage wall surface of the partition wall 33 and the rear surface of the circumferential belt 293 of the shutter 205 in the bypass opening operation, wherein the actuator 9 actuates the shutter 205. When the bypass opening operation of the shutter 205 is started, the speed of the EGR gas flow is substantially zero in the vicinity of the back surface of the circumferential flap. 293. The EGR gas, which has a substantially zero flow velocity, arrives at the rear surface of the shutter 205 immediately after the commencement of the bypass opening operation. The EGR gas pressure, which has a substantially zero flow rate, is greater than the pressure of the EGR gas which flows at high speed along the front surface of the shutter 205.

  Therefore, the lifting force can be enhanced by the EGR gas which has a substantially zero flow velocity, which has the effect of assisting the bypass opening operation, so that the shutter 205 can be operated immediately with less actuation force. The response characteristic of the actuator 9 can therefore be improved. It is possible to reduce the outside diameter of the diaphragm 60 when the vacuum applied from the vacuum pump into the vacuum chamber 66 of the actuator 9 is the same. It is therefore possible to reduce the dimensions of the actuator 9.

  The shutter 205 has the curved shape, so that the lifting force can be increased in the bypass opening operation. The actuation force required for the bypass opening operation of the shutter 205 can be reduced. The first sealing surface 291 of the shutter 205 can easily be separated from the first seat portion 91 of the first seat 11, thereby reducing the power consumption of the electric vacuum pump. The housings 64, 65 define the interior space (diaphragm chamber) inside. The diaphragm chamber comprises the vacuum chamber 66 which contains the coil spring 68. The coil spring 68 applies a biasing force to the diaphragm 60 so that the first shutter surface 291 of the shutter 205 is applied against the diaphragm 60. first seat part 91 of the first seat 11. Even when an external form, in particular a vibration, is transmitted by the motor E to the shutter 205, through the bearing of the partition wall 33 of the body 4, the coil spring 68 applies the grounding force to the shutter 205 so that the shutter 205 is applied to the first seat 11 when the shutter 205 is in the complete closed position of the bypass. Therefore, it is possible to prevent vibration of the shutter 205 in which the shutter 205 is lifted from the first seat portion 91 of the first seat 11, and pressed against it repeatedly. In addition, it is possible to significantly reduce the leakage of the shutter 205 when the shutter 205 is in the complete closed position of the bypass, which significantly improves the reliability of the switching valve 3.

  A flap may be partially set on the shutter 205. In this case, the circumferential periphery of the shutter 205 may be curved toward the first shutter surface 291, so that the circumferential periphery of the shutter 205 is inclined by relative to the average flow axis of the EGR gas from the first inlet port 41 to the cooler inlet passage 42 when the shutter 205 is in the fully closed position of the bypass. A flap, which is substantially arcuate in shape, can be established on the shutter 205 so that the flap becomes larger from the downstream of the EGR gas flow entering the coolant inlet passage. 42 through the first inlet port 41, upstream of the EGR gas flow. A flap, which is substantially arcuate in shape, can be established on the shutter 205 only downstream of the flow of EGR gas entering the cooler inlet passage 42 through the first inlet port 41. Third Embodiment As shown in FIGS. 17 to 21, the body 4 has inside a protective block 113 formed in one piece with the rest of the body. The protection block 113 protects the shutter shaft 6, so that the high temperature EGR gas and the low temperature EGR gas do not directly meet the shutter axis 6. A bearing portion 136 The bearing portion 136 is substantially cylindrical in shape to slidably support the shutter axis 6. The bearing portion 136 has an axle hole therein. The axis hole extends in the axial direction of the shutter axis 6. The shutter shaft 6 can rotate in the axis hole. The pinhole has an axial end which defines an opening in the bearing portion 136. The plug 37 is tightly tightened in the body 4 to close the opening of the pinhole. A plug 40 closes openings of the cooling water passages in the body 4. The shutter shaft 6 has an axial end projecting out of the body 4 through the plug 37. Referring to the figures 17, 21, it is noted that functional components are placed between the outer circumferential periphery of the shutter shaft 6 and the inner circumferential periphery of the bearing portion 136. The functional components comprise an axis guide 73, the portion fixed 74, first and second rings 75, 76 and a seal for the gas 79. The fixed portion 74 and the first ring 75 are fixed to the outer periphery of the shutter axis 6, by welding or other . The first and second rings 75, 76 are formed of a metallic material, in one piece, so as to have substantially cylindrical shapes. The first and second rings 75, 76 define a labyrinth to prevent foreign matter, which is contained in the gas --EGR which enters the space between the bearing portion 136 and the obturator axis 6 For example, the bushing 77 is formed in one piece of a carbon-based material, which has an excellent sliding property, so as to have a substantially cylindrical shape. The bushing 77 is a bearing component for slidably supporting the shutter shaft 6 in the direction of rotation. The gas seal, 79, is a cylindrical member which is formed in one piece of an elastomer such as rubber, for example. The gas seal 79 acts as a sealing member to prevent foreign matter contained in the EGR gas from entering the space between the bearing portion 136 and the d-axis. obiator 6.

  The protection block 113 is formed in one piece with the partition wall 33 of the body 4. The protective block 113 circumferentially surrounds the periphery of the shutter axis 6. The protection block 113 surrounds circumferentially the periphery of the gas seal, 79, mounted on the shutter shaft 6. The protection block 113 comprises first and second protectors 191, 192. The first protector 191 protects the shutter shaft 6, the bearing portion 136 of the body 4, and the gas seal, 79, which is mounted on the shutter shaft 6, against the high temperature EGR gas. The second protector 192 protects the shutter shaft 6 and the bearing portion 136 of the body 4 against an adhesive substance such as adhesive carbon held in the low temperature EGR gas. The first protector 191 defines a body wall (block) which is exposed in the cooler inlet passages 42 to 44 in the body 4. The first protector 191 comprises an arcuate wall surface 193, and a decreasing wall surface, 194. The arcuate wall surface 193 defines a portion of the circumferential periphery extending substantially along the circumferential outer periphery of the shutter axis 6. The surface As shown in FIG. 1, the wall protrusion 194 projects protrudingly to reduce the cross-sectional area of the cooler inlet passage 44. The second protector 192 has a decreasing wall surface 195 which protrudes substantially to reduce the cross-sectional area of the cooler outlet passage 52. The protective block 113 -a - an opening 190 which defines a cavity, which is larger than the width of the shutter lever 7, and has a sufficient volume to include the path according to which the lev The aperture 190 prevents the shutter lever 7 from encountering the protective block 113. The end of the decreasing wall surface, 195, of the se- The protector 192 of the protection block 113 defines the throttle 56. The shutter lever 7 has a V-shaped portion 197 on the lower side in Fig. 19. The end of the wall surface decreases. , 195, protrudes beyond at least the lowest level of the V-shaped portion 197 in Fig. 19, when the shutter 5 is in the fully closed position of the shunt. The decreasing wall surface 195 also serves the function of a guide wall surface which guides the flow of EGR gas to the second outlet port 55 so that the wall surface decreases. , 195, deviates from the shutter axis 6 the EGR gas flowing from the outlet of the EGR cooler 2 into the cooler outlet passage 52 through the opening 190. Referring to Figures 17, 21, it is noted that the gas seal, 79, is tightly mounted on the outer circumferential periphery of the shutter shaft 6, so that the EGR gas 110 at high temperature can not flow through the space between the shutter shaft 6 and the sleeve 77. In addition, the shutter pin 6 is protected against seizing by the effect of minute particles including an adhesive substance such as adhesive carbon contained in the low-temperature EGR gas. Referring to FIGS. 17 to 19, it will be noted that when the shutter 5 is in the fully closed position of the bypass, a cooler communication path is established. The cooler communication path includes the first inlet port 41, the cooler inlet passages 42 to 44, the first outlet port 45, the EGR cooler 2, the second inlet port 51, cooler outlet 52, 53 and the second outlet port 55, in that order. Referring to FIGS. 18, 20, it will be noted that when the shutter 5 is in the complete closed position of the cooler, a bypass communication path is established. The bypass communication path includes the first inlet port 41, the cooler inlet passage 42, the bypass passages 34, 35, the cooler outlet passage 53 and the second outlet port 55, this order. The protective block 113 is formed in one piece with the partition wall 33 of the body 4, so that the protection block 113 surrounds both the periphery of the shutter shaft 6 and the periphery of the gasket. gas-tightness, 79, using the body 4 about the shutter axis 6. In this structure, the high-temperature EGR gas, which is emitted by the engine E and is introduced into the Cooler inlet passages 42 to 44, either in the bypass passages 34, 35, through the first inlet port 41, is deflected with respect to the shutter axis 6. Therefore, the shutter 6 can be protected against the heat of the EGR gas at high temperature. The heat of the high temperature EGR gas can not be transmitted to the shutter shaft 6 through the cooler inlet passages 42 to 44 or the bypass passages 34, 35, so that it can not not to exert a thermal effect on the shutter shaft 6. The heat of the high-temperature EGR gas can not be transmitted via the shutter shaft 6 to the gas seal, 79, which is mounted on the shutter shaft 6, so that it can not exert a thermal effect on the seal for the gas, 79. Therefore, the seal for the gas, 79 , can be protected against heat deterioration of EGR gas at high temperature. As a result, the sealing performance of the gas seal 79 can be maintained, so that the hermeticity between the outer circumferential periphery of the shutter shaft 6 and the inner circumferential periphery of the seal axis hole defined in the bearing portion 136 of the body 4 can be maintained. As a result, it is possible to limit EGR gas leakage and galling of the shutter shaft 6, so that the reliability and durability of the switch valve 3 can be improved. The protection block 113 circumferentially surrounds the periphery of the shutter shaft 6. The low temperature EGR gas, which is introduced into the cooler outlet passages 52, 53 from the EGR cooler 2, is The shutter shaft 6 and the bearing portion 136 can be protected against minute particles and adhesive substances contained in the low-temperature EGR gas. It is possible to prevent ad-hesive substances contained in the low-temperature EGR gas from adhering between the shutter shaft 6 and the bearing portion 126, and it is possible to prevent them from accumulate between the shutter shaft 6 and the bearing portion 126. Therefore, the operation of the shutter shaft 6 with respect to the bearing portion 136 can be maintained. As a result, the shutter 5 can be operated smoothly, so that the reliability and durability of the switch valve 3 can be improved. When the temperature of the high temperature EGR gas is relatively low, the cooling water passages in the body 4 can be omitted. In this case, the hot water pipes 21, 23 and the cooling water pipes 22, 24 may be omitted. The body 4 can be simplified, so that the cost of manufacture can be reduced. An air passage (thermal insulation layer), through which air can pass, can be established between the first and second protectors 191, 192 of the protection block 113 and the bearing portion 136. A passage of cooling water may be established between the first and second protectors 191, 192 of the protection block 113 and the bearing portion 136 for cooling the bearing portion 136 and the bearing components. The first and second seats 11, 12 may be extended so that the first and second seats 11, 12 surround the protection block 113. The derivation passages 34, 35 may be omitted in the body 4. The passages cooler inlet 42 to 44 or the cooler outlet passages 52, 53 may be sufficient. The protection block 113 defines a portion of the cylindrical surface along the shutter axis 6.

  Therefore, the distance between the shutter axis 6 and the cooler inlet passages 42 to 44 and the cooler outlet passages 52, 53 can be constantly maintained. In addition, it is possible to reduce the flow resistance for the flow of EGR gas that passes through the cooler inlet passages 42 to 44 and the cooler outlet passages 52, 53. The protective block 113 makes protrusion so as to reduce the cross-sectional area of the cooler outlet passage 52. The protection block 113 protects the shutter shaft 6 against adhesive substances contained in the low-temperature EGR gas. The helical spring reduces the vibration of the shutter 5. The coil spring reduces the leakage of the shutter 5, which allows to restrict a temperature increase of the EGR gas at low temperature. Modification The shutter actuator device may consist of an electric actuator or a solenoid actuator including an electric motor and a transmission device such as a reduction gear. The biasing element such as the coil spring 68 may be incorporated in the body 4.

  The shutter 5, 205 may consist of various kinds of shutters, such as a plate type shutter and a rotating shutter. The switching valve can change the operating angle of the shutter continuously or stepwise between the complete closed position of the bypass and the fully closed position of the cooler. The diverting valve can fulfill the function of an exhaust temperature control valve to control the temperature of the EGR gas (exhaust gas), which is recycled to the intake system of the engine E, controlling the mixing ratio of the low temperature EGR gas passing through the EGR cooler 2 and the high temperature EGR gas passing through the bypass passages 34, 35. The diverting valve can perform the function of a single channel valve The rear surface of the shutter may have a substantially spherical shape or a substantially arcuate shape, such that the EGR gas progressively changes its direction of flow when the shutter is closed. in the fully closed position of the cooler. The switch valve may be applied to an exhaust gas cooler such as an EGR cooler module having an exhaust gas cooler defining an S-shaped fluid passage therein or In this case, an outlet chamber of the exhaust gas cooler is connected to the second inlet port 51 of the body 4 by a pipe, which does not give rise to a heat exchange.

  The first seat can be formed directly around the opening of the first communication hole defined in the partition wall 33 of the body 4. In this structure, the first seat can be formed in one piece with the body 4.

  The second seat can be formed directly around the opening of the second communication hole defined in the rectilinear pipe portion 31 of the body 4. In this structure, the second seat can be formed in one piece with the body 4.

  The connection between the first rectilinear passage 31a and the second rectilinear passages 34, 35, 53 is not limited to having the substantially T-shaped shape. The axes of the bypass passages 34, 35 and the vertical line which is perpendicular to the The axis of the first rectilinear passage 31a can define an acute angle between them, so that the connection between the axes of the bypass passages 34, 35 and the vertical line can have substantially a shape in y. The bypass passage may be a curved passage, which has a substantially arcuate shape. In this structure, the bypass passage curves progressively from the branch portion (cooler inlet passage 42), in which the bypass passage separates from the first straight passage 31a, toward the collecting portion (passage cooler outlet 53), wherein the bypass steps and the L-shaped passage 32a meet. The connection between the L-shaped passage 32a and the bypass steps 34, 35 is not limited to having a substantially T-shape. The L-shaped passage 32a may be a straight passage 32a. extending from the outlet of the EGR cooler 2 to the second outlet port 55 of the body 4, perpendicular to the axes of the bypass passages 34, 35. In this structure, the connection between this straight passage 32a and the bypass passages 34, 35 may have a substantially T shape. In this structure, the connection between this straight passage 32a, the bypass passages 34, 35 and the first straight passage 31a may define a passage having substantially an H shape. 4. The connection between this straight passage 32a and the bypass passages 34, 35 may be substantially Y-shaped. The L-shaped passage 32a may be a curved passage, which is substantially form e n arc, extending from the outlet of the EGR cooler 2 to the second outlet port 55 of the body 4. In this structure, the pressure drop of the EGR gas flow passing through the L-shaped passage 32a can be reduced in the normal operation of the engine E. The EGR cooler 2 may have passages which differ from each other with respect to cooling performance. The referral valve may switch to cooler communication passages communicating with these passages of the EGR cooler 2 respectively. The actuator 9 may be a positive pressure actuator which applies a positive pressure in the atmospheric chamber 67, which is greater than at atmospheric pressure. In this structure, diaphragm 60 is moved using a pressure difference between a pressure chamber, which communicates with the atmosphere, and a pump chamber, which communicates with a pump. In this case, the pump a-eirps air through an air inlet, and evacuates pressurized air through an air outlet, thereby supplying pressurized air to the pump chamber. . The biasing element may be incorporated in the body 4 of the switching valve 3. The fluid passing through the body 4 may consist of various other kinds of fluid, such as fuel vapor evaporated from a fuel tank, the intake air sucked into cylinders of the engine E, and a vaporized cooling fluid used for a cooling cycle. The fluid passing through the body 4 is not limited to a gas such as EGR gas. The fluid passing through the body 4 may be a motor cooling fluid 4, a liquid such as a cooling fluid used for a cooling cycle, or a two-phase cooling fluid, gas-liquid, used for a cooling cycle , for example. The body may have a substantially T-shaped branch passage having first and second outlet ports in relation to a single inlet port, and the T-shaped branch passage may contain the shutter. In this structure, a rectilinear passage, which extends rectilinearly from the inlet to the first outlet, defines a fluid passage, and a branch port, which branches from an intermediate position through the straight passage and extends to the second outlet, defines a through hole. The shutter can be rotated to open and close the straight passage. The body may have a substantially T-shaped gathering passageway having first and second inlet ports in relation to a single outlet port, and the T-shaped branch passageway may contain the shutter. In this structure, a rectilinear passage, which extends rectilinearly from the first inlet port to the outlet port, defines a fluid passage, and a branch port, which branches from the second input port and collects in an intermediate position through the straight passage, defines a through hole. The shutter can be rotated to open and close the straight passage. The body can be connected to the outlet of the EGR cooler 2, so that the shutter can be placed downstream of the EGR cooler 2, when considering the flow direction of the exhaust gas. In this structure, it is possible to rotate the shutter to open and close the cooler outlet passage communicating with the outlet of the EGR cooler 2. The body may not necessarily be connected to the inlet or the outlet of a cooler. heat exchanger such as the EGR cooler 2. A heat exchanger such as the EGR cooler 2 can be omitted. It goes without saying that many other modifications can be made to the embodiments without departing from the scope of the present invention.

Claims (49)

  , 1. A valve (3) connected to a cooler (2) for cooling a recycled exhaust gas in an engine intake system (E), the valve (3) being characterized in that it comprises: a body (4) having a coolant inlet passage (42,44) communicating with an inlet of the cooler (2), the body (4) further having a cooler outlet passage (52) communicating with an outlet the cooler (2), the body (4) including a first seat (11) defining inside a stepping step (35); and a shutter (5, 205) which is movable in the body (4); and in that when the shutter (5, 205) is lifted from the first seat (11), the cooler inlet passage (42, 44) communicates with the cooler outlet passage (52) through the passage of bypassing (35), bypassing the cooler (2), when the shutter (5, 205) is applied to the first seat (11), the shutter (5, 205) is in a fully closed position of the bypass, wherein the shutter (5, 205) closes the bypass passage (35), and the complete closure position of the bypass is between the cooler inlet passage (42, 44) and the outlet passage cooler (52). 20   2. Valve (3) according to claim 1, characterized in that the first seat (11) faces the cooler inlet passage (42, 44), and when the shutter (5, 205) is raised from the first seat (11) to the cooler inlet passage (42,44), the cooler inlet passage (42,44) communicates with the cooler outlet passage (52) through the bypass passage (35) .   3. Valve (3) according to claim 1 or 2, characterized in that the first seat (11) is a first cylindrical member (11) which is introduced with tightening in the body (4), and the complete closed position of the The bypass is located axially on the side of the coolant inlet passage (42, 44), relative to the first cylindrical member (11).   4. Valve (3) according to any one of claims 1 to 3, characterized in that the first seat (11) has an annular projection which reduces a contact area between the shutter (5) and the first seat (11). ).   5. Valve (3) according to any of claims 1 to 4, characterized in that the body (4) has a collecting portion (53) in which the cooler outlet passage (52) communicates with the passage bypass (35), the body (4) has a throttle (56) which is placed on the outlet side of the cooler (2) with respect to the joining portion (53), and the throttle (56) defines a passage having a section that is smaller than a section of an opening that provides a required flow rate of exhaust gas passing through the cooler outlet passage (52).   Valve (3) according to one of Claims 1 to 5, characterized in that the first seat (11) has a first passage hole (34) which at least partially defines the bypass passage (35). ), the body (4) comprises a second seat (12) which has a second pas-sage hole (43) defining at least in part the coolant inlet passage (42, 44), the shutter (5, 205) takes one or the other of two positions including the complete closure position of the bypass and a complete closed position of the cooler, when the shutter (5, 205) is in the complete closed position of the bypass , the shutter (5, 205) is applied to the first seat (11) to close the first through hole (34), when the shutter (5, 205) is in the complete closed position of the cooler, the shutter (5,205) is applied to the second seat (12) to close the second through hole (43), the body (4) defines an inlet port (41). ) through which the exhaust gas enters the coolant inlet passage (42, 44), the complete closed position di, cooler is substantially coaxial with the inlet ohfice (41), and Na position of The complete closure of the cooler is opposite to the inlet port (41).   7. Valve (3) according to claim 6, characterized in that the first seat (11) is a first cylindrical member (II) which is introduced with tightening in the body (4), Ne second seat (12) is a second a cylindrical member (12) which is inserted into the body (4), the complete closed position of the bypass is located axially on the side of the coolant inlet passage (42, 44) with respect to the first cylindrical member (11). ), and the complete closing position of the cooler is placed axially on the side of the inlet orifice (41) with respect to the second cylindrical member (12).   8. Valve (3) according to claim 6 or 7, characterized in that the shutter (5, 205) constitutes a shutter member capable of passing from one to the other of the two positions.   9. Valve (3) according to any one of claims 6 to 8, characterized in that it further comprises: an axis (6) which can rotate in the body (4); and a lever (7) which connects the shutter (5, 205) to the axis (6); and in that the lever (7) has a first end which is attached to an outer periphery of the shaft (6), the lever (7) has a second end on the other side with respect to the first end the second end being attached to the shutter (5,205), and the shutter (5,205) constitutes a shutter member (5,205) which is rotatable about the first end of the lever (7). ) for selectively opening and closing the first through-hole (34) and the second through-hole (43) on the side of the second end of the lever (7).   10. Valve (3) according to any one of claims 6 to 9, characterized in that it comprises: a shutter actuating device which comprises an actuator (9) for generating a driving force under the effect of the application of a depression, which is lower than the atmospheric pressure; and the shutter actuator actuates the shutter (5, 205) to move from one to the other of the two positions using the driving force of the actuator (9).   11. Valve (3) according to any one of claims 1 to 10, characterized in that the body (4) has an outlet (45) which communicates with the inlet_ of the cooler (2), the body (4) ) comprises a straight pipe portion (31) which extends substantially rectilinearly from the inlet (41) to the outlet (45), the inlet (41) opens upstream of the straight pipe portion (31) when considering an exhaust flow direction, and the straight pipe portion (31) defines the coolant inlet passage (42) therein , 44).   Valve (3) according to one of claims 1 to 11, characterized in that the body (4) has a collecting portion (53) in which the cooler outlet passage (52) communicates with the passage of bypass (35), the body (4) has an L-shaped pipe portion (32) which is bent substantially at a right angle to define the inside portion (53) and the pipe portion L-shaped (32) defines inside the cooler outlet passage (52).   13. Valve (3) according to any one of claims 1 to 12, characterized in that the shutter (5, 205) is placed upstream of the cooler (2) when considering a gas flow direction of exhaust, the body (4) has inside a coolant communication passage (31, 32), the exhaust gas is recycled into the engine intake system (E) through the cooler communication passage (31, 32) and the cooler (2), the body (4) has an inlet (41) through which the exhaust gas passes to enter at least the coolant communication passage (31, 32). ), and the cooler communication passage (31, 32) has a rectilinear passage (31a) extending substantially rectilinearly from the inlet (41) to the inlet of the cooler (2) .   Valve (3) according to claim 13, characterized in that the coolant communication passage (31, 32) has an L-shaped passage (32a) which is bent substantially at a right angle, the L-shaped passage. (32a) is connected to the straight passage (31a) through the cooler (2), and the straight passage (31a) is adapted to communicate with the L-shaped passage (32a) through the bypass passage (35). ) in the body (4).   Valve (3) according to claim 14, characterized in that the body (4) comprises a straight pipe part (31) and a L-shaped pipe part (32), the straight pipe part (31) ) internally defines the straight passage (31a), and the L-shaped pipe portion (32) defines the L-shaped passage (32a) therein.   16. Valve (3) according to claim 14 or 15, characterized in that the bypass passage (35) is substantially perpendicular to an axis of the rectilinear passage (31a).   17. Valve (3) according to any one of claims 14 to 16, characterized in that the body (4) has an outlet (55), the exhaust gas flows from at least the passage of communicating cooler (31, 32) to an outside of the cooler communication passage (31, 32), through the outlet (55), the straight passage (31a) communicates with the inlet of the cooler (2) , the exhaust gas flows from the inlet port (41) to the cooler inlet (2) through the straight passage (31a), the L-shaped passage (32a) communicates with the outlet of the cooler (2), the exhaust gas flows from the outlet of the cooler (2) to the outlet (55) through the L-shaped passage (32a), and the bypass passage (35) communicates the rectilinear passage (31a) with the L-shaped passage (32a) in the body (4).   Valve (3) according to one of Claims 13 to 17, characterized in that the shutter (5, 205) can rotate in the straight passage (31a), and the shutter (5, 205) opens and closes at least the bypass passage (35).   Valve according to claim 18, characterized in that when the shutter (5, 205) is a fully open position of the bypass, the bypass passage (35) is open, the complete closure position of the bypass and the full open position of the bypass defines an operating angle of the shutter (5, 205), and the operating angle is an acute angle.   20. Valve (3) according to claim 18 or 19, characterized in that when the shutter (5, 205) is in a fully open position of the bypass, the bypass passage (35) is open, and a The end surface of the shutter (5) is opposed to the inlet orifice (41), and when the shutter (5, 205) is in the fully open position of the shunt, the normal to the end surface of the shutter (5,205) is inclined towards the bypass passage (35) with respect to a vertical line which is perpendicular to the axis of the first rectilinear passage (31a).   21. Valve (3) according to any one of claims 13 to 20, characterized in that the body (4) comprises a first seat (11) and a second seat (12), the first seat (11) defines the a first through hole (34), the second seat (12) internally defines a second through-hole (43), the shutter (5, 205) can be moved in the rectilinear passage ( 31a), the shutter (5, 205) passes from one to the other of the two positions including the complete closure position of the bypass and the full open position of the bypass, when the shutter (5, 205) is in the fully closed position of the shunt, the obturator (5, 205) is applied to the first seat (11) to close the first through-hole (34), and the second through-hole ( 43) is or-green, when the shutter (5, 205) is in the fully open position of the bypass, the shutter (5, 205) is applied to the second seat (12) for closing the second through-hole (43), and the first through-hole (34) is open, the shutter (5, 205) constitutes a shutter member (5, 205) which selectively opens and closes the first hole of step (34) and the second through-hole (43), the first through hole (34) defines at least a portion of the bypass passage (35), and the second through-hole (43) defines at least one part of the cooler communication passage (31, 32).   22. Valve (3) according to claim 21, characterized in that the complete closure position of the bypass and the complete opening position of the bypass define between them an operating angle of the shutter (5, 205), and the operating angle is an acute angle.   23. Valve (3) according to claim 21 or 22, characterized in that it further comprises: a shutter actuating device which actuates the shutter (5, 205) to pass from one to the other. other of the two positions including the fully closed position of the bypass and the full open position of the bypass.   24. Valve (3) according to any one of claims 1 to 12, characterized in that the body (4) has a fluid passage which has a first through hole (34) in an intermediate position through it, the step -sage fluid forms a branching or gathering in the first through hole (34), the shutter (205) has a sealing surface (291) which is adapted to be applied on a periphery (91) of the first hole passage (34) for closing the first through hole (34), the shutter (205) has a flap (293) which is placed on the outer side in a radial direction of the closure surface (291), and the flap (293) is formed by folding an outer circumferential periphery of the shutter (205) towards the sealing surface (291).   25. Valve (3) according to claim 24, characterized in that the first through hole (34) is substantially perpendicular to a direction of flow of the exhaust gas passing through the fluid passage.   26. Valve (3) according to claim 24 or 25, characterized in that the body (4) has an annular space (30) which surrounds the opening periphery (91), and the flap (293) is placed at least partially in the annular space (30).   27. Valve (3) according to any one of claims 24 to 26, characterized in that it further comprises: an actuator (9) which actuates the shutter (205); and in that the actuator (9) defines inside a first pressure chamber (66) and a second pressure chamber (67), the first pressure chamber (66) communicates with a vacuum source, the second pressure chamber (67) communicates with the atmosphere, the actuator (9) comprises a diaphragm (60) which is displaced in accordance with the difference between the pressure in the first pressure chamber (66) and the pressure in the second chamber pressure (67), and the actuator (9) generates a driving force when a depression, which is lower than the atmospheric pressure, is applied in the first pressure chamber (66) to lift the sealing surface (291) of the shutter (205) from the opening periphery (91) of the first through hole (34).   28. A valve (3) according to claim 27, characterized in that 2 (1 the actuator (9) further comprises a spring (68) which applies a biasing force to the diaphragm (60), so that the surface shutter (291) of the shutter (205) is urged towards the opening periphery (91) of the first through hole (34).   Valve (3) according to claim 27 or 28, characterized in that the actuator (9) further comprises a rod (61) which can be axially offset in conjunction with the diaphragm (60) for actuating the valve. shutter (205).   Valve (3) according to claim 29, characterized in that it further comprises: an axle (6) rotatable in the body (4), a motion transforming element (62) which is connected to the rod (61) and connected to the axis (6), and in that the motion-transforming element (62) converts a rectilinear movement of the rod (61) into a rotational movement of the axis (6). ), and the shutter (205) is a shutter shutter (205) which is rotatable about the axial direction of the axis (6). 35   31. Valve (3) according to any one of claims 24 to 30, characterized in that the body (4) is connected to the inlet of the cooler (2) which cools the exhaust gas leaving the engine (E). and is recycled to the engine intake system (E), and the shutter (205) is placed upstream of the cooler (2) when considering the flow direction of the exhaust gas.   32. Valve (3) according to claim 31, characterized in that the body (4) has inside a cooler communication passage (31, 32) and the bypass passage (35), the exhaust gas is recycled to the engine intake system (E) through the cooler communication passage (31, 32) and the cooler (2), the exhaust gas is recycled to the engine intake system (E ) through the bypass passage (35) bypassing the cooler (2), the fluid passage defines a portion of the cooler communication passage (31, 32), and the first through hole (34) defines a part of the bypass passage (35).   33. Valve (3) according to claim 32, characterized in that the shutter (205) opens and closes at least the bypass passage (35).   34. Valve (3) according to claim 32, characterized in that the shutter (205) puts into operation one or the other of the coolant communication passage (31, 32) and the bypass passage ( 35).   35. Valve (3) according to any one of claims 1 to 12, characterized in that it further comprises: an axis (6) which can be moved integrally to the shutter (5, 205); and in that the body (4) contains a block (113) and the block (113) surrounds the axis (6).   36. Valve (3) according to claim 35, characterized in that the block (113) defines a portion of a substantially cylindrical surface along an outer periphery of the axis (6).   37. Valve (3) according to claim 35 or 36, characterized in that the body (4) contains a coolant communication passage (31, 32), the exhaust gas is recycled into the intake system of the engine (E) through the cooler communication passage (31, 32) and the cooler (2), and the block (113) protrudes to reduce a cross sectional area of the coolant communication passage (31, 32). Valve (3) according to any one of claims 35 to 37, characterized in that the body (4) has a bearing portion (136) which supports the axis (6) in a sliding manner via a bearing component (77), a sealing member (79) is interposed between the shaft (6) and the bearing portion (136), and the sealing member (79) provides a hermetic connection between the axis (6) and the bearing portion (136). Valve (3) according to Claim 38, characterized in that the block (113) protects the sealing member (79) against the heat of the exhaust gas passing through the coolant communication passage (31, 32). . 40. Valve (3) according to any one of claims 35 to 39, characterized in that the block (113) protects the shaft (6) against the heat of the exhaust gas passing through the cooler communication passage (31). , 32). 41. Valve (3) according to any one of claims 35 to 40, characterized in that the block (113) protects the axis (6) against an adhesive substance contained in the exhaust gas passing through the communication passage of cooler (31, 32). Valve (3) according to one of Claims 35 to 41, characterized in that the body (4) has an inlet (41) through which the exhaust gas enters the passage. communicating cooler (31, 32) which is connected to both the chiller inlet (2) and the chiller outlet (2), the body (4) has an outlet port (55) through which the exhaust gas passes from the cooler communication passage (31, 32) to an outside of the cooler communication passage (31, 32), the cooler communication passage (31, 32) includes a passage of cooler inlet (42, 44) extending from the inlet port (41) to the cooler inlet (2), and the cooler communication passage (31, 32) includes a passageway cooler outlet (52) extending from the outlet of the cooler (2) to the outlet (55). 43. Valve (3) according to claim 42, characterized in that the bypass passage (35) communicates the cooler inlet passage (42, 44) with the cooler outlet passage (52). 44. Valve (3) according to claim 43, characterized in that it further comprises: a lever (7) which connects the shutter (5, 205) to the axis (6); and in that the lever (7) has a first end which is attached to an outer periphery of the axis (6), the lever (7) has a second end on a side other than that of the first end, the second end is attached to the shutter (5,205), and the shutter (5,205) is rotatable about the first end of the lever (7) to selectively open and close the coolant inlet passage ( 42, 44) and the bypass passage (35) on the side of the second end of the lever (7). 45. A valve (3) according to claim 43 or 44, characterized in that the shutter (5, 205) is rotatable in the coolant inlet passage (42, 44) to pass from one to the other. other of two positions including the complete closure position of the bypass and a complete closing position of the cooler, when the shutter (5, 205) is in the complete closed position of the bypass, the shutter (5, 205 ) closes the bypass passage (35), and the coolant inlet passage (42, 44) is open, and when the shutter (5, 205) is in the complete closed position of the cooler, the shutter (5, 205) closes the cooler inlet passage (42, 44), and the bypass passage (35) is open. 46. Valve (3) according to claim 45, characterized in that it further comprises: a shutter actuating device which comprises an actuator (9) for generating a driving force under the effect of the application of a depression, which is below atmospheric pressure; and. in that the shutter actuating device actuates the shutter (5, 205) so as to place it in both positions by using the driving force of the actuator (9). 47. Valve (3) according to any one of claims 43 to 46, characterized in that the body (4) comprises a first seat (11) which defines inside the bypass passage (35), the shutter (5, 205) closes the bypass passage (35) by being applied to the first seat (11), and the shutter (5, 205) opens the bypass passage (35) by being lifted from the first seat (11) . 48. Valve (3) according to claim 47, characterized in that it further comprises: a biasing element (68) which urges the shutter (5, 205) towards the first seat (11). 49. An exhaust gas recirculation device for a motor (E), the exhaust gas recirculation device being characterized in that it comprises: a cooler (2) which cools the recycled exhaust gas in an engine intake system (E), the cooler (2) having an inlet and an outlet through which the exhaust gas passes; and a valve (3) which comprises a body (4) having a coolant inlet passage (42,44) communicating with the inlet of the cooler (2), the body (4) further having an outlet passage of cooler (52) communicating with the outlet of the cooler (2), the body (4) including a first seat (11) defining inside a shunt step (35); and in that the valve (3) further comprises a shutter (5, 205) which can be moved in the body (4), when the shutter (5, 205) is lifted from the first seat (11), the passage cooler inlet (42, 44) communicates with the cooler outlet passage (52) through the bypass passage (35), bypassing the cooler (2), when the shutter (5, 205) is applied to the first seat (11), the shutter (5, 205) is in a fully closed position of the bypass, wherein the shutter (5, 205) closes the bypass passage (35), and the The complete closure position of the bypass is located between the cooler inlet passage (42, 44) and the cooler outlet passage (52).