Exhaust gas recirculation valve

Abstract

The exhaust gas recirculation valve (1A) comprises: a valve core (7) which is driven along an axial direction to open and close an exhaust gas passage (3); a housing (2) which has an exhaust gas passage (3) inside and is provided with an exhaust gas flow outlet (5) connected to the exhaust gas passage (3), the exhaust gas flow outlet being arranged in a direction perpendicular to the axial direction of the valve core (7); and a cover member (12) which is arranged in front of an inner wall surface (2A) of the housing (2) which is opposite to the exhaust gas flow outlet (5).

Description

Technical Field

[0001] The present disclosure relates to an exhaust gas recirculation valve. Background Art

[0002] Exhaust gas recirculation valves are known that direct a portion of the exhaust gas generated by an internal combustion engine to the intake side for circulation. For example, Patent Document 1 describes an exhaust gas recirculation valve comprising a valve housing having a gas communication passage therein and a valve that is driven axially to open and close the gas communication passage.

[0003] Prior art literature

[0004] Patent Literature

[0005] [Patent Document 1]

[0006] Japanese Patent Application Laid-Open No. 2005-325785 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] When the exhaust gas passage is opened, the rapidly flowing exhaust gas collides with the inner wall surface of the housing facing the exhaust gas outlet, thereby causing erosion or corrosion due to the exhaust gas colliding with the inner wall surface.

[0009] The present disclosure is to solve the above technical problems, and its purpose is to obtain an exhaust gas recirculation valve that can prevent damage to the inner wall surface of the housing caused by the collision of exhaust gas.

[0010] Technical solutions used to solve technical problems

[0011] The exhaust gas recirculation valve disclosed herein includes a valve core that is driven along an axial direction to open and close an exhaust gas passage; a housing that internally defines an exhaust gas passage and is provided with an exhaust gas flow outlet connected to the exhaust gas passage, the exhaust gas flow outlet being arranged in a direction perpendicular to the axial direction of the valve core; a plunger member that blocks the housing from the axial direction of the valve core; and a cover member that is arranged in front of an inner wall surface of the housing that is opposite to the exhaust gas flow outlet. The cover member is sandwiched between the housing and the plunger member.

[0012] Effects of the Invention

[0013] According to the present disclosure, since the flow of the exhaust gas toward the inner wall surface of the casing is blocked by the cover member, it is possible to prevent the inner wall surface of the casing from being damaged by the collision of the exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing the exhaust gas recirculation valve in a closed state.

[0015] Figure 2It is a cross-sectional view showing the exhaust gas recirculation valve in an open state.

[0016] Figure 3 This is a map showing the results of fluid analysis of the exhaust gas recirculation valve in the open state.

[0017] Figure 4 It only means Figure 3 Image of the flow velocity in the Y direction.

[0018] Figure 5 This is a cross-sectional view showing the exhaust gas recirculation valve according to the first embodiment.

[0019] Figure 6 Yes Figure 5 A partially cutaway perspective view of the structure of an exhaust gas recirculation valve.

[0020] Figure 7 It is a cross-sectional view showing a modified example of the exhaust gas recirculation valve according to the first embodiment.

[0021] Figure 8 It is a perspective view showing the appearance of the exhaust gas recirculation valve according to the first embodiment. DETAILED DESCRIPTION

[0022] Implementation Method 1

[0023] Figure 1 : is a cross-sectional view showing the exhaust gas recirculation valve 1 in a closed state. Figure 2 1 is a cross-sectional view showing the exhaust gas recirculation valve 1 in an open state. The housing 2 of the exhaust gas recirculation valve 1 is formed of, for example, cast iron, and the exhaust gas passage 3 is formed of, for example, cast iron. Figure 1 as well as Figure 2 As shown, the exhaust gas passage 3 is formed inside the housing 2. The exhaust gas passage 3 is connected to an exhaust gas inlet 4 and two exhaust gas outlets 5 and an exhaust gas outlet 6.

[0024] The exhaust gas recirculation valve 1 is, for example, a so-called double poppet valve, which opens and closes a path in the exhaust passage 3 for allowing exhaust gas to flow from the exhaust inlet 4 to the exhaust outlet 5 and a path for allowing exhaust gas to flow from the exhaust inlet 4 to the exhaust outlet 6 .

[0025] like Figure 1 As shown, the exhaust passage 3 becomes closed by the contact between the valve core 7 and the valve seat 8. Figure 2 As shown in FIG. 1 , the exhaust passage 3 is opened by separating the valve core 7 from the valve seat 8. The valve core 7 is fixed to the valve shaft 9 and moves along the axial direction integrally with the valve shaft 9. Figure 1 as well as Figure 2The drive source is omitted from the illustration. It includes a DC motor and a mechanism that converts the motor's rotational motion into linear motion of the output shaft. The drive source causes the valve shaft 9 to move linearly along its axis, thereby moving the valve core 7 along its axis. The valve shaft 9 is supported by bearings 10.

[0026] The plunger member 11 is a member that blocks the housing 2 from the axial direction of the valve core 7. The housing 2 has a hole, for example, in the axial direction of the valve core 7. During the manufacturing process of the exhaust gas recirculation valve 1, the valve seat 8 is machined through this hole. The plunger member 11 is mounted in the hole of the housing 2, blocking the exhaust gas passage 3 of the housing 2 from the axial direction of the valve core 7.

[0027] The exhaust gas outlet 5 is provided on the housing 2 at a position perpendicular to the axial direction of the valve element 7. When the valve element 7 separates from the valve seat 8 and the exhaust gas recirculation valve 1 is opened, the exhaust gas flows into the exhaust gas passage 3 from the exhaust gas inlet 4 to the exhaust gas outlet 5 as shown by the arrow A.

[0028] Figure 3 It is a map showing the results of fluid analysis of the exhaust gas recirculation valve 1 in the open state, and illustrates the flow velocity distribution of the exhaust gas. Figure 4 It only means Figure 3 The image of the velocity distribution in the Y direction. Figure 3 as well as Figure 4 The flow velocity distribution of FIG shows that the darker the color of the image representing the flow of the exhaust gas, the faster the flow of the exhaust gas. Figure 4 It is obvious that when the exhaust gas recirculation valve 1 is in the open state, the exhaust gas indicated by the arrow A collides with the inner wall surface 2A of the housing 2 facing the exhaust gas outlet 5 in a relatively fast flow.

[0029] When exhaust gas strikes the inner wall of casing 2, the moment of impact causes a change in the fluid momentum of the exhaust gas, generating impact pressure. This impact pressure gradually scrapes away the inner wall of the casing due to erosion. Furthermore, when an internal combustion engine uses natural gas as fuel, the exhaust gas contains a high concentration of water vapor. In this case, erosion due to the impact of the exhaust gas and corrosion due to the water vapor in the exhaust gas can occur on the inner wall 2A of the cast iron casing 2.

[0030] Figure 5 This is a cross-sectional view showing an exhaust gas recirculation valve 1A according to the first embodiment. Figure 6 It is a partially cutaway perspective view showing the structure of the exhaust gas recirculation valve 1A, and only the housing 2 is shown in cross section. Figure 5 as well as Figure 6 In the Figure 1 as well as Figure 2The same components are denoted by the same reference numerals. In order to prevent erosion and corrosion caused by the impact of the exhaust gas, the exhaust gas recirculation valve 1A includes a cover member 12 in addition to the components of the exhaust gas recirculation valve 1 .

[0031] The cover member 12 is made of, for example, stainless steel and is provided in front of the inner wall surface 2A of the housing 2 facing the exhaust gas outlet 5. The cover member 12 is composed of a cover portion 13 and a support portion 14. Figure 6 As shown in FIG, the cover portion 13 is a plate-shaped member that is arranged in front of the inner wall surface 2A while being supported by the support portion 14. The support portion 14 is an annular member formed integrally with the cover portion 13.

[0032] The plunger member 11 is as follows Figure 5 as well as Figure 6 As shown, the housing 2 comprises a circular plate portion forming the bottom surface thereof and a cylindrical portion extending axially from the peripheral edge of the circular plate portion. Furthermore, a flange portion 2B is provided on the peripheral edge of the opening on the inner side of the housing 2 at the hole portion of the housing 2 into which the plunger member 11 is mounted. The flange portion 2B extends from the peripheral edge of the opening of the hole portion, and the opening diameter of the flange portion 2B is smaller than the diameter of the circular plate portion of the plunger member 11.

[0033] The outer diameter of the support portion 14 is smaller than the inner diameter of the hole portion of the housing 2 where the plunger member 11 is installed, and is larger than the opening diameter of the flange portion 2B. The cover member 12 is inserted into the hole portion of the housing 2 in a direction in which the cover portion 13 is located in front of the inner wall surface 2A until the support portion 14 contacts the flange portion 2B. Then, the plunger member 11 is inserted into the hole portion of the housing 2 in a state in which the circular plate portion faces the inner side of the housing 2 and the inner wall surface of the hole portion of the housing 2 contacts the outer circumference of the cylindrical portion until the circular plate portion contacts the support portion 14. Thus, as Figure 5 As shown, the cover member 12 is sandwiched between the housing 2 and the plunger member 11 and fixed to the housing 2 .

[0034] Since the cover portion 13 is arranged in front of the inner wall surface 2A, Figure 4 The flow of exhaust gas toward the inner wall surface 2A, indicated by arrow A, is blocked by the cover portion 13. This mitigates the impact pressure of the exhaust gas striking the inner wall surface 2A of the outer shell 2, suppressing the occurrence of erosion. Furthermore, the stainless steel cover member 12 prevents the exhaust gas, which contains a high amount of water vapor, from directly impacting the cast iron outer shell 2, thereby suppressing the occurrence of corrosion. Thus, in the exhaust gas recirculation valve 1A, damage to the inner wall surface 2A of the outer shell 2 caused by the impact of exhaust gas can be prevented.

[0035] In addition, at the portion other than the inner wall surface 2A of the housing 2 facing the exhaust gas outlet 5, that is, at the inner wall surface close to the exhaust gas outlet 5, as shown in FIG. Figure 4As shown, the flow rate of the exhaust gas flowing in when the valve is open is lower than the flow rate of the exhaust gas toward the inner wall surface 2A. The impact pressure caused by the exhaust gas impacting the inner wall surface is proportional to the exhaust gas flow rate. Therefore, due to the exhaust gas impact, a greater impact pressure is generated on the inner wall surface 2A opposite the exhaust gas outlet 5 than on the inner wall surface closer to the exhaust gas outlet 5. To this end, the cover member 12 is positioned in front of the inner wall surface 2A to block the flow of exhaust gas impacting the inner wall surface 2A.

[0036] Although the exhaust gas recirculation valve 1A is shown as a double poppet valve, any type of poppet valve is acceptable. For example, the valve element 7 of the exhaust gas recirculation valve 1A may be a single poppet valve, or may be three or more poppet valves.

[0037] Shell 2 Figure 5 As shown, a coolant circuit 15 is provided. Coolant circuit 15 is a flow path for coolant flow. The coolant is primarily composed of, for example, ethylene glycol, which heats up easily and cools down slowly. When the internal combustion engine is started in a low-temperature environment, the coolant flowing in coolant circuit 15 absorbs heat from the engine through the walls of the housing 2, causing the coolant temperature to rise before the ambient temperature rises. By allowing the heated coolant to flow through coolant circuit 15, the heat from the coolant helps to eliminate ice inside the housing 2.

[0038] Figure 7 It is a cross-sectional view of an exhaust gas recirculation valve 1B which is a modified example of the exhaust gas recirculation valve 1A. Figure 7 In the Figure 1 as well as Figure 2 The same components are denoted by the same reference numerals. The exhaust gas recirculation valve 1B includes a cover member 12A instead of the cover member 12 included in the exhaust gas recirculation valve 1A.

[0039] The cover member 12A is a member formed of, for example, stainless steel and is provided in front of the inner wall surface 2A of the housing 2, similarly to the cover member 12. The cover member 12A is composed of a cover portion 13 and a support portion 14A. The cover portion 13 is a plate-shaped member that is arranged in front of the inner wall surface 2A while being supported by the support portion 14A. The support portion 14A is a Figure 5 The plunger member 11 shown in FIG. 1 is a member that acts as a piston. That is, the support portion 14A is as shown in FIG. Figure 7 As shown, the cover 13 includes a disk portion constituting the bottom surface of the housing 2 and a cylindrical portion extending from the peripheral edge of the disk portion in the axial direction. The cover 13 is formed integrally with the disk portion of the support 14A.

[0040] Cover member 12A is inserted into the hole of housing 2, with the circular plate portion of support portion 14A facing inward and the inner wall surface of the hole of housing 2 contacting the outer periphery of the cylindrical portion, until the circular plate portion contacts flange portion 2B. Cover member 12A is thereby secured to housing 2. Since cover member 12A also functions as plunger member 11, an increase in the number of components is minimized.

[0041] Figure 8 It is a perspective view showing the appearance of the exhaust gas recirculation valve 1A. Figure 8 In the embodiment, the driving source 16 is mounted on the housing 2. The driving source 16 includes a DC motor and a mechanism for converting the rotational motion of the DC motor into the linear motion of the output shaft. Figure 5 and Figure 6 The valve shaft 9 shown in FIG. 1 is an actuator that moves linearly along the axial direction. Figure 8 The coolant flows in the coolant circuit 15 of the straight pipe as shown by arrow C.

[0042] For example, when the coolant circuit is curved, the coolant will collide with the inner wall surface of the curved portion of the coolant circuit. If the coolant hits the inner wall surface of the curved portion at a high flow rate, erosion or corrosion will also occur inside the coolant circuit. Figure 8 As shown, by forming the coolant circuit 15 into a straight pipe structure, the coolant is suppressed from colliding with the inner wall surface of the coolant circuit 15 at a high flow rate, thereby preventing the occurrence of erosion and corrosion.

[0043] As described above, the exhaust gas recirculation valve 1A of the first embodiment includes: a valve element 7, which is driven along the axial direction to open and close the exhaust gas passage 3; a housing 2, which internally defines the exhaust gas passage 3 and is provided with an exhaust gas outlet 5 connected to the exhaust gas passage 3, the exhaust gas outlet 5 being arranged in a direction perpendicular to the axial direction of the valve element 7; and a cover member 12, which is provided in front of the inner wall surface 2A of the housing 2, which is opposite the exhaust gas outlet 5. Since the flow of exhaust gas toward the inner wall surface 2A of the housing 2 is blocked by the cover member 12, damage to the inner wall surface 2A of the housing 2 caused by the impact of exhaust gas can be prevented.

[0044] In the exhaust gas recirculation valve 1A of the first embodiment, the cover member 12 is sandwiched between the housing 2 and the plunger member 11. The existing plunger member 11 can be utilized to secure the cover member 12 to the housing 2. This reduces the number of components required to install the cover member 12. Furthermore, the cover member 12 can be easily installed to the housing 2 using the same procedures as the plunger member 11.

[0045] In the exhaust gas recirculation valve 1B of the first embodiment, the cover member 12A is integrally formed with the support portion 14A, which serves as the plunger member. Since the cover member 12A also functions as the plunger member 11, the increase in the number of components required to install the cover member 12A is minimized. Furthermore, the cover member 12A can be easily installed in the housing 2 using the same procedures as the plunger member 11.

[0046] Furthermore, any constituent elements of the embodiments may be modified or omitted.

[0047] Industrial applicability

[0048] The exhaust gas recirculation valve disclosed herein can be used in, for example, an internal combustion engine that uses natural gas as a fuel.

[0049] Explanation of symbols

[0050] 1, 1A, 1B exhaust gas recirculation valve; 2 outer shell; 2A inner wall surface; 2B flange portion; 3 exhaust gas passage; 4 exhaust gas inlet; 5, 6 exhaust gas outlet; 7 valve core; 8 valve seat; 9 valve shaft; 10 bearing; 11 plunger member; 12, 12A cover member; 13 cover portion; 14, 14A support portion; 15 coolant circuit; 16 drive source.

Claims

1. An exhaust gas recirculation valve, characterized in that: include: a valve core, the valve core being driven along an axial direction to open and close the exhaust gas passage; a housing having the exhaust gas passage therein and provided with an exhaust gas flow outlet connected to the exhaust gas passage, the exhaust gas flow outlet being arranged in a direction perpendicular to the axial direction of the valve core; a plunger member, the plunger member sealing the housing from the axial direction of the valve core; as well as a cover member provided in front of an inner wall surface of the housing facing the exhaust gas flow outlet, The cover member is sandwiched between the housing and the plunger member, The cover member includes a cover portion and a support portion. The cover portion is a plate-shaped member that is arranged in front of the inner wall surface of the housing while being supported by the support portion.

2. The exhaust gas recirculation valve according to claim 1, characterized in that The cover member is formed integrally with the plunger member and is sandwiched between the housing and the plunger member.

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