EXHAUST ENGINE RECIRCULATION DEVICE

Abstract

Exhaust gas recirculation device (S), comprising: an EGR cooler (2) provided in an EGR passage (1) which causes exhaust gas to be recirculated from an exhaust section of an engine (E) of the vehicle to an intake section; and an EGR line (3) which is provided in the engine (E) and directs the exhaust gas flowing from the EGR cooler (2) to the intake section, wherein the EGR line (3) includes: an inlet area (31) into which the exhaust gas flowing out of the EGR cooler (2) flows; a flow path (32) through which the exhaust gas flowing in from the inlet area (31) flows; and an outlet area (33) from which the exhaust gas flowing through the flow path (32) escapes, and wherein the flow path (32) is provided such that its height on the side of the flow path (32) decreases compared to its height on the side of the outlet region (33), and has a region in which a distance between a center line (L1) of a flow path cross-section of the flow path (32) and a line (L2) along a lowest end region in the vertical direction of the flow path cross-section from the side of the outlet region (33) towards the side of the inlet region (31) gradually increases, wherein The flow path cross-section of the flow path (32) has a constant cross-sectional area and gradually changes from a circle to a polygon from the side of the outlet area (33) to an end area on the side of the inlet area (31).

Description

[Technical field]

[0001] The present invention relates to an exhaust gas recirculation device in a vehicle. [Background of the invention]

[0002] Vehicles are typically equipped with an exhaust gas recirculation (EGR) system. Japanese patent application JP 2019-7389A1 discloses an EGR line located above an engine, which carries the exhaust gas flowing from an EGR cooler to an intake manifold. Furthermore, WO 2018 / 110351A1 discloses an EGR system that integrates a gas-liquid separation function into the EGR cooler to separate liquids contained in the exhaust gas. For this purpose, a helically wound vortex-generating band is arranged in the cooler's outlet pipe, imparting a swirl flow to the exhaust gas. Centrifugal force carries the liquid phase to the inner wall of the pipe, where it is discharged through a drainage opening. A V-shaped tapered end of the vortex-generating band is intended to prevent previously separated liquid droplets from being re-entrained. [Brief description of the invention][Problem solution according to the invention]

[0003] Since condensation forms in the EGR line, it is necessary to drain this condensate to a predetermined location. Current technologies present the challenge of finding a design solution for draining the condensate from the EGR line to a predetermined location while simultaneously avoiding an increase in engine compartment size.

[0004] An objective of the present invention is to provide an exhaust gas recirculation device in which condensed water can be easily drained from the EGR line, while preventing an enlargement of the EGR line in the vertical direction of the vehicle. [Means to solve the problem]

[0005] The problem underlying the present invention is solved by an exhaust gas recirculation device with the features of claim 1. Advantageous embodiments and further developments of the invention are the subject of the dependent claims. [Technical effect of the invention]

[0006] According to the present invention, it is possible in the exhaust gas recirculation device to prevent an enlargement of the EGR line in the vertical direction of the vehicle and to easily drain condensate from the EGR line. [Brief description of the drawings] Fig. Figure 1 shows a state in which an exhaust gas recirculation device according to the present embodiment is provided in an engine. Fig. Figure 2 shows the design of an EGR line. Fig. Figure 3 shows a cross-sectional view of the EGR pipe; Fig. Figure 4 schematically shows a flow path in which the flow path cross-section gradually changes from a circular shape to a polygon. Fig. Figure 5 shows a configuration near a head covering when the in Fig. 1 The exhaust gas recirculation device shown and provided in an engine is viewed from above. Fig. Figure 6 shows the condition of an inlet area of ​​the EGR line with respect to the cylinder head cover. Fig. Figure 7 shows the condition of the head cover when the head cover is removed from a cylinder head housing. [Description of embodiments][State in which the exhaust gas recirculation device S is provided in the engine E.]

[0007] Fig. Figure 1 shows a state in which an exhaust gas recirculation device according to the present embodiment is provided in an engine. The exhaust gas recirculation device S has an EGR (exhaust gas recirculation) passage 1, an EGR cooler 2 and an EGR line 3.

[0008] The EGR passage 1 is a passage for recirculating exhaust gas from an exhaust section (not shown) of the vehicle's engine E to an intake section (not shown). The engine E is, for example, a gasoline or diesel engine. The engine E comprises a cylinder head housing 4 and a cylinder head cover 5. The cylinder head housing 4 contains an intake valve (not shown), an exhaust valve (not shown), a camshaft (not shown), and the like. The cylinder head cover 5 is a cover for the cylinder head housing 4. The cylinder head cover 5 can be attached to and removed from the cylinder head housing 4.

[0009] The exhaust section is a section through which the exhaust gas generated in the combustion chamber of engine E flows. The exhaust section includes, for example, an exhaust pipe. The exhaust section is located on the right side of the engine. Fig. 1 of the depicted engine E. Since every component (e.g. exhaust section and the like) on the exhaust side of engine E is exposed to hot exhaust gases, these components are often made of cast iron or the like with sufficient thickness.

[0010] The intake section is a section through which air flows towards the combustion chamber of engine E. The intake section is located on the left side of the [unclear - possibly referring to the engine]. Fig. 1 of the depicted engine E. To reduce the weight of the individual components (e.g. the intake section and the like) on the intake side of the engine E, a thin aluminum material or resin is often used.

[0011] The EGR cooler 2 cools the exhaust gas flowing into it. The EGR cooler 2 cools the exhaust gas through heat exchange between the exhaust gas and the cooling water. The EGR cooler 2 is located in the EGR passage 1. One end of the EGR cooler 2 is connected to an outlet section. The exhaust gas flowing out of the outlet section flows into the EGR cooler 2.

[0012] The EGR line 3 is a component for conveying the exhaust gas flowing from the EGR cooler 2 towards the intake section. The EGR line 3 is located in the EGR passage 1. One end of the EGR line 3 is connected to the other end of the EGR cooler 2. The exhaust gas flowing from the EGR cooler 2 flows into the EGR line 3. The other end of the EGR line 3 is connected to the intake section. The exhaust gas flowing from the EGR line 3 flows into the intake section. The EGR line 3 is located, for example, above the engine E. In particular, the EGR line 3 is located above the cylinder head cover 5 in a configuration where its longitudinal direction extends in the width direction of the engine E. It should be noted that Fig. Figure 1 shows only one example of the arrangement of the EGR line 3. In addition to the one in Fig. In the example shown in Figure 1, where the EGR line 3 is provided above the head cover 5, the EGR line 3 can be located in front of or behind the cylinder head housing 4. [Structure of the EGR line 3]

[0013] Fig. Figure 2 shows the design of an EGR line. Fig. 2A is a view showing a configuration near the EGR line 3 in a state where the in Fig. 1 Exhaust gas recirculation device S shown is provided in the engine E, with the viewing point being on the rear of the vehicle. Fig. Figure 2B shows a view of the EGR line 3 and the cylinder head cover 5 in a state where the in Fig. 1 shows an exhaust gas recirculation device S provided in the engine E, with the viewing point being on the front of the vehicle.

[0014] Fig. Figure 3 shows a cross-sectional view of the EGR pipe. Fig. 3A shows a cross-sectional view along the line X1-X1 of Fig. 2A. Fig. 3B shows a cross-sectional view along the line X2-X2 of Fig. 2A. Fig. 3C shows a cross-sectional view along the X3-X3 line of Fig. 2A. Fig. 3D shows a cross-sectional view along the X4-X4 line of Fig. 2A. Fig. 3E shows a cross-sectional view along the X5-X5 line of Fig. 2A. The positions of line X2-X2, line X3-X3 and line X4-X4 in the longitudinal direction of EGR line 3 correspond to the positions of the distances 1 / 4, 1 / 2 and 3 / 4 from line X1-X1 when the distance between line X1-X1 and line X5-X5 is set to 1.

[0015] The EGR line 3 comprises an inlet section 31, a flow path 32, and an outlet section 33. The inlet section 31 is a section into which the exhaust gas flowing from the EGR cooler 2 enters. The inlet section 31 has an opening through which the exhaust gas flows. The flow path 32 is a section through which the exhaust gas flowing from the inlet section 31 passes. The outlet section 33 is a section into which the exhaust gas flowing through the flow path 32 exits. The outlet section 33 has an opening through which the exhaust gas flowing through the flow path 32 passes.

[0016] As in Fig. As shown in Figure 2, the flow path 32 is designed such that its height decreases on the side of the inlet region 31 compared to its height on the side of the outlet region 33. In other words, the flow path 32 is designed such that it gradually decreases in height towards the exhaust side of the engine E.

[0017] Since the exhaust gas, cooled by the EGR cooler 2, flows within the EGR line 3, condensation of moisture produces condensate, which is a liquid containing exhaust gas components. Because the condensate contains a high concentration of exhaust gas components, contact with the individual components (aluminum or resin material) on the intake side can lead to corrosion and damage to these components.

[0018] For this reason, the EGR line 3 preferably has a configuration in which the condensate accumulates on the exhaust side of the engine E (where the components in this area are made of cast iron or similar material of sufficient thickness). Since the flow path 32 in the exhaust gas recirculation device S is designed such that its height on the side of the inlet area 31 is lower than its height on the side of the outlet area 33, the condensate can flow from the inlet side of the engine E to the outlet side of the engine E. Therefore, the ingress of condensate into the inlet area can be prevented, and each component on the inlet side can be protected.

[0019] As in Fig. As shown in Figure 2A, the flow path 32 has a region in which the distance between a center line L1 of a flow path cross-section of the flow path 32 and a line L2 along a lowest end region in the vertical direction of the flow path cross-section of the flow path gradually increases from the side of the outlet region 33 towards the side of the inlet region 31.

[0020] The center line L1 is a line along the midpoint of the flow path cross-section of flow path 32. The line L2 along the lowest end region is a line formed by connecting several points at the lowest end region within flow path 32 in the longitudinal direction of flow path 32. The condensed water in flow path 32 flows along line L2.

[0021] As in Fig. As shown in Figure 3, the flow path 32 has a cross-sectional area that is, for example, constant, and the flow path cross-section gradually changes from a circle to a polygon from the side of the outlet region 33 towards the frontal region on the side of the inlet region 31. In particular, the flow path cross-section of the flow path 32 gradually changes from a circle to a quadrilateral shape from the side of the outlet region 33 towards the end region on the side of the inlet region 31. More precisely, the flow path cross-section of the flow path 32 is formed in such a way that one of the corners of the quadrilateral shape is positioned at the lowest end region, in the region with the quadrilateral cross-section. In such a configuration, as shown in the Fig. 3A and Fig. As shown in 3E, the distance d from the center line L1 to the lowest position gradually increases. Consequently, as shown in Fig. 2A shows the distance between the center line L1 and the line L2 gradually in the direction of the side of the inlet area 31.

[0022] The fact that the distance between the center line L1 and the line L2 gradually increases towards the inlet area 31 means that the angle of inclination of line L2, which corresponds to the gradient of the flow path through which the condensed water flows, can be greater than the angle of inclination of the center line L1. According to the EGR line 3 of the present embodiment, the condensed water can be easily drained by such a design.

[0023] Fig. Figures 4A to 4C each show a diagram that schematically illustrates a flow path 7 with a flow path cross-section that gradually changes from a circular shape to a square shape. Fig. Figure 4A shows a diagram illustrating the flow path 7 with a flow path cross-section that gradually changes from a circular shape to a square shape in the longitudinal direction. Fig. Figure 4B shows a diagram illustrating the circular flow path cross-section at one end of the flow path 7. Fig. Figure 4C shows a diagram illustrating the square flow path cross-section at the other end of flow path 7.

[0024] If in flow path 7 the area of ​​the circular flow path cross-section ( Fig. 4B) and the area of ​​the quadrilateral flow path cross-section ( Fig. 4C) If both are 1, the height (1.41) of the rectangular flow path cross-section becomes greater than the height (1.13) of the circular flow path cross-section if the rectangular flow path cross-section is arranged such that one corner of the rectangular shape is located at the lowest end. If the upper end of the flow path 7 is horizontal, the rectangular flow path cross-section lies lower at its lowest end than the circular flow path cross-section at its lowest end. Therefore, the inclination angle of the lower end of the flow path 7 is increased. Such an effect can also be achieved if the flow path cross-section is, for example, a polygon such as a triangle, a pentagon, or a hexagon.

[0025] In the exhaust gas recirculation device S, even if the inclination angle of the EGR line 3 with respect to the horizontal direction is made relatively small, a sufficient angle of the bottom surface of the flow path 32, through which the condensed water in the EGR line 3 flows, can easily be ensured with respect to the horizontal direction. Therefore, in the exhaust gas recirculation device S, the condensed water can be easily drained from the EGR line 3, while an enlargement of the EGR line 3 in the vertical direction of the vehicle is suppressed.

[0026] In the exhaust gas recirculation device S, the EGR line 3 is provided with the flow path 32 described above. As the exhaust gas flows from the side of the inlet area 31 to the side of the outlet area 33, the flow path cross-section gradually changes from a polygon to a circle, thus reducing the pressure loss.

[0027] Furthermore, in the exhaust gas recirculation device S, the EGR line 3 with the flow path 32 is provided with a square flow path cross-section, with one corner arranged at the lowest end region of the flow path cross-section, as described above. Therefore, the condensed water in the EGR line 3 collects within this corner of the square, so that the condensed water can easily drain away.

[0028] As in Fig. As shown in Figure 2, the centerline L1 of the flow path cross-section of flow path 32 and the line L2 along the lowest end region in the vertical direction of the flow path cross-section of flow path 32 are straight lines. Since both the centerline L1 and the line L2 along the lowest end region are straight lines in the exhaust gas recirculation device S, the bending section of the EGR line 3 is reduced, thus decreasing the pressure loss of the EGR line 3. Although the flow path of the present embodiment has a relatively complex cross-sectional shape, in a case such as this, where the centerline L1 and the line L2 are, for example, straight lines, it is easy to form the components. The centerline L1 and the line L2 can extend in a direction that is orthogonal to a direction in which, for example, several cylinders of the engine E are arranged.

[0029] Furthermore, the weight of the EGR line 3 in the exhaust gas recirculation device S can be reduced because the flow path 32, through which the exhaust gas and condensed water flow, can be shortened. Since the bending section of the EGR line 3 is reduced, it is also less likely that stress concentrations will occur due to heat or vibration, thus making the EGR line 3 less prone to damage. [Placement of the EGR line 3 in relation to the head cover 5]

[0030] Fig. Figure 5 shows a configuration near a head cover 5, when the in Fig. 1 The exhaust gas recirculation device S shown and provided in an engine E is viewed from above.

[0031] The engine E has several fastening elements 6. Each fastening element 6 is a component for attaching the cylinder head cover 5 to the cylinder head housing 4. Each fastening element 6 is, for example, a bolt. The multiple fastening elements 6 are arranged at the edge of the cylinder head cover 5. The cylinder head cover 5 is attached to the cylinder head housing 4 by inserting the fastening elements 6 into openings (not shown) formed in the cylinder head cover 5 and into openings (not shown) formed in the cylinder head housing 4, thereby securing the fastening elements 6.

[0032] The user can remove the cylinder head cover 5 from the cylinder head housing 4 in a state where the multiple fasteners 6 are released from the cylinder head cover 5 and the cylinder head housing 4. In particular, the user can remove the cylinder head cover 5 from the cylinder head housing 4 by moving the cylinder head cover 5 towards the front of the vehicle with respect to the cylinder head housing 4, in a state where the multiple fasteners 6 are released from the cylinder head cover 5 and the cylinder head housing 4.

[0033] As in Fig. As shown in Figure 5, the EGR line 3 is located above the cylinder head cover 5, so that it is not positioned above the multiple fastening elements 6. By locating the EGR line 3 in the exhaust gas recirculation device S, the multiple fastening elements 6 can be detached from the cylinder head cover 5 and the cylinder head housing 4, for example, when adjusting the valve clearance, without having to detach the EGR line 3 and the EGR cooler 2. Therefore, with the exhaust gas recirculation device S, the cylinder head cover 5 can be easily removed from the cylinder head housing 4.

[0034] Fig. 6A and Fig. Figure 6B each shows a view illustrating a state of the inlet area 31 of the EGR line 3 with respect to the head cover 5. Fig. Figure 6A shows a view illustrating a condition in which a tool V comes into contact with the fastening elements 6 on the respective sides of the inlet area 31 of the EGR line 3. Fig. 6A corresponds to a cross-sectional view along line YY of Fig. 5. Fig. Figure 6B shows a view illustrating a condition in which the tool V comes into contact with the fastening elements 6 on the respective sides of an inlet area 91 of an EGR line 9 and serves as a comparison example.

[0035] As in Fig. As shown in Figure 6A, the inlet area 31 of the EGR line 3 is inclined relative to the cylinder head cover 5, so that the distance between the inlet area 31 and the cylinder head cover 5 increases towards the front of the vehicle. As shown in Fig. 6B shows that if the inlet area 91 of the EGR line 9 is not inclined with respect to the head cover 5, since the length of the inlet area 91 in the longitudinal direction of the vehicle is greater than the length between the multiple fastening elements 6 in the longitudinal direction of the vehicle, the tool V, which releases the multiple fastening elements 6, disturbs the inlet area 91.

[0036] On the other hand, as in Fig. As shown in Figure 6A, in the exhaust gas recirculation device S, the inlet area 31 of the EGR line 3 is inclined with respect to the cylinder head cover 5 such that the distance between the inlet area 31 and the cylinder head cover 5 increases towards the front of the vehicle, and the length of the inlet area 31 in the longitudinal direction of the vehicle is less than the length between the several fastening elements 6 in the longitudinal direction of the vehicle. Therefore, in the exhaust gas recirculation device S, the tool V, which releases the fastening element 6, does not interfere with the inlet area 31.

[0037] Fig. Figure 7 shows the state of the head cover 5 when the head cover 5 is removed from a cylinder head housing 4. Fig. 7 corresponds to a cross-sectional view extending along line ZZ from Fig. 5 was recorded. In the exhaust gas recirculation device S, as described above, the inlet area 31 of the EGR line 3 is inclined relative to the cylinder head cover 5, so that the distance between the inlet area 31 and the cylinder head cover 5 increases towards the front of the vehicle. Therefore, a gap forms between the lower surface of the inlet area 31 and the cylinder head cover 5 attached to the cylinder head housing 4, which increases towards the front. In other words, as in Fig. As shown in Figure 7, a lower surface of the inlet area 31 is inclined with respect to the head cover 5, such that the vertical distance between the inlet area 31 and the head cover 5 increases in a direction in which the head cover 5 moves when the head cover 5 is moved away from the cylinder head housing 4.

[0038] As a result, as in Fig. Figure 7 shows that when the cylinder head cover 5 is removed from the cylinder head housing 4 and moved towards the front of the vehicle, the cylinder head cover 5 is tilted with respect to the horizontal direction, so that the front of the cylinder head cover 5 is positioned higher in the longitudinal direction of the vehicle than the rear of the cylinder head cover 5 in the longitudinal direction of the vehicle. Therefore, in the exhaust gas recirculation device S, the cylinder head cover 5 can be easily removed from the cylinder head housing 4.

[0039] As in Fig.As shown in Figure 2, the lower surface of the EGR line 3, viewed from the rear and front of the vehicle, has a shape that follows the upper surface of the cylinder head cover 5, and a gap is formed, for example, between the lower surface of the EGR line 3 and the upper surface of the cylinder head cover 5. Since the exhaust gas recirculation device S has such an EGR line 3, the cylinder head cover 5 can be moved upwards relative to the cylinder head housing 4 when the cylinder head cover 5 is removed from the cylinder head housing 4. This allows the cylinder head cover 5 to be easily removed from the cylinder head housing 4 within the exhaust gas recirculation device S. [Technical effects of the exhaust gas recirculation device S according to the present embodiment]

[0040] The exhaust gas recirculation device S according to the present embodiment comprises the EGR line 3, which is provided such that the height of the side of the inlet area 31 is lower than the height of the side of the outlet area 33, and the flow path 32 with a region in which a distance between a center line L1 of a flow path cross-section of the flow path 32 and a line L2 along a lowest end region in the vertical direction of the flow path cross-section of the flow path 32 gradually increases from the side of the outlet area 33 towards the side of the inlet area 31.

[0041] Consequently, even if the angle of inclination of the EGR line 3 with respect to the horizontal direction is small, a sufficient angle of the bottom surface of the flow path 32, through which the condensed water in the EGR line 3 flows, can easily be ensured in the exhaust gas recirculation device S. Therefore, the condensed water can be easily drained from the EGR line 3 in the exhaust gas recirculation device S, while an enlargement of the EGR line 3 in the vertical direction of the vehicle is prevented.

[0042] Although the present embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the embodiments described above, and various modifications and changes can be made without deviating from the scope of the present invention. For example, the entire device or a part thereof can be functionally or physically separated and integrated into any unit. Furthermore, new embodiments resulting from any combination of several embodiments are included in the present embodiments. The technical effects of the new embodiment resulting from the combination are the same as those of the original embodiment. [Description of reference symbols] Exhaust gas recirculation device 1 EGR flow path 2 EGR coolers 3 EGR line 31 Entrance area 32 Flow path 33 Outlet area Electric motor 4 cylinder head housings 5 Head Cover 6 Fastening element 7 Flow path L1 Center line of the flow path cross-section L2 line along the lowest end region in the vertical direction of the flow path cross-section V tool 9 EGR line as a comparative example 91 Entrance area 92 Flow path

Claims

[1] Exhaust gas recirculation device (S), comprising: an EGR cooler (2) provided in an EGR passage (1) which causes exhaust gas to be recirculated from an exhaust section of an engine (E) of the vehicle to an intake section; and an EGR line (3) which is provided in the engine (E) and directs the exhaust gas flowing from the EGR cooler (2) to the intake section, wherein the EGR line (3) includes: an inlet area (31) into which the exhaust gas flowing out of the EGR cooler (2) flows; a flow path (32) through which the exhaust gas flowing in from the inlet area (31) flows; and an outlet area (33) from which the exhaust gas flowing through the flow path (32) escapes, and wherein the flow path (32) is provided such that its height on the side of the flow path (32) decreases compared to its height on the side of the outlet region (33), and has a region in which a distance between a center line (L1) of a flow path cross-section of the flow path (32) and a line (L2) along a lowest end region in the vertical direction of the flow path cross-section from the side of the outlet region (33) towards the side of the inlet region (31) gradually increases, wherein The flow path cross-section of the flow path (32) has a constant cross-sectional area and gradually changes from a circle to a polygon from the side of the outlet area (33) to an end area on the side of the inlet area (31). [2] Exhaust gas recirculation device (S) according to claim 1, wherein the center line (L1) and the line (L2) along the lowest end region are straight lines. [3] Exhaust gas recirculation device (S) according to claim 1, wherein the flow path cross-section of the flow path (32) gradually transitions from a circular shape to a rectangular shape from the side of the outlet area (33) towards the end area on the side of the inlet area (31), and in the area of ​​the flow path cross-section which has the rectangular shape, a corner of the rectangular shape is arranged at the lowest end area of ​​the flow path cross-section. [4] Exhaust gas recirculation device (S) according to claim 3, wherein the engine (E) comprises: a cylinder head housing (4) containing an inlet valve, an exhaust valve and a camshaft; a cylinder head cover (5) that can be attached to and removed from the cylinder head housing (4) and covers the cylinder head housing (4) from above; and several fastening elements (6) for attaching the cylinder head cover (5) to the cylinder head housing (4), which can be inserted from above into openings formed in the cylinder head cover (5) and into openings formed in the cylinder head housing (4); and the EGR line (3) is provided with a design which is located above the head cover (5), but not above the several fastening elements (6). [5] Exhaust gas recirculation device (S) according to claim 4, wherein a lower surface of the inlet area (31) is inclined with respect to the head cover (5) such that a vertical distance between the inlet area (31) and the head cover (5) increases in a direction in which the head cover (5) moves when the head cover (5) is removed from the cylinder head housing (4).

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