JP2020002827A - Intake system of engine - Google Patents

Abstract

To provide an intake system of an engine which can distribute EGR gas to each back equally while achieving reduction of a length of an EGR gas pipe.SOLUTION: An intake system 20 of an engine 1 includes: an intake pipe 21 in which air flows; branch pipes 22A, 22B which are branched from the intake pipe 21 and respectively connected to a left bank 2A and a right bank 2B; an EGR gas pipe 25 which is connected to a branch part 26 where the intake pipe 21 and the branch pipes 22A, 22B are connected and into which EGR gas flows; and an EGR lead-out pipe 28 which is disposed at the branch part 26 and guides the EGR gas flowing in the EGR gas pipe 25 into the branch pipes 22A, 22B. The EGR lead-out pipe 28 has: a cylindrical part 30; and a vertical wall part 31 which is disposed at an interior of the cylindrical part 30 and partitions the passages 32A, 32B respectively communicating with the branch pipes 22A, 22B from each other. A cutout part 33 opening on a front end surface 31a is provided at a front end surface 31a side (an EGR gas pipe 25 side) portion of the vertical wall part 31.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an intake device for an engine.

  2. Description of the Related Art As an intake device for an engine, for example, a technique described in Patent Document 1 is known. The air intake device described in Patent Literature 1 has an air introduction portion in which a circular air introduction port connected to a throttle valve is opened on a side wall, left and right collective intake pipes branched from the air introduction portion and extending along left and right banks. The EGR gas discharge port is provided on the side wall of the air inlet so as to face the air inlet and communicates with the EGR gas supply pipe through the through hole. And a partition wall provided with a communication hole arranged coaxially with the EGR gas discharge port. The intake air supplied from the air introduction port to the intake introduction space of the air introduction part is blocked by the partition wall and branched into the left and right collective intake pipes. The EGR gas supplied from the EGR gas discharge port to the EGR gas introduction space of the air introduction unit is blocked by the partition and branched into the left and right collective intake pipes. Part of the intake air that has passed through the air introduction port passes through the communication hole of the partition wall and flows into the EGR gas introduction space.

JP-A-8-284767

  By the way, in order to distribute the EGR gas equally to the left and right banks, it is necessary to lengthen the EGR gas pipe through which the EGR gas flows. However, in recent years, it has become difficult to lengthen the EGR gas pipe along with downsizing of the engine and the like. Therefore, even if the EGR gas pipe is shortened, it is desired to distribute the EGR gas evenly to the left and right banks.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an intake device for an engine capable of uniformly distributing EGR gas to each bank while shortening an EGR gas pipe.

  One embodiment of the present invention relates to an intake device for an engine provided in an engine having two banks and inducting air and EGR gas into the two banks, respectively. Two branch pipes respectively connected to the bank, an EGR gas pipe connected to a branch part connected to the intake pipe and the branch pipe, through which EGR gas flows, and an EGR gas arranged in the branch part and flowing through the EGR gas pipe And an EGR lead-out pipe for guiding each of the EGR lead-out pipes into two branch pipes. The EGR lead-out pipe is a vertical wall which is disposed inside the cylindrical part and partitions two passages respectively communicated with the two branch pipes. And a notch that is open at the end surface on the EGR gas tube side of the vertical wall portion on the EGR gas tube side.

  In such an intake system for an engine, when the EGR gas pipe through which the EGR gas flows is short, the swirling flow of the EGR gas easily reaches a branch portion where the intake pipe, the EGR gas pipe, and each branch pipe are connected. Since the drift tends to occur in the branch portion, it becomes difficult to distribute the EGR gas evenly to each bank. Therefore, in one aspect of the present invention, the EGR outlet pipe that guides the EGR gas flowing through the EGR gas pipe into the two branch pipes is disposed at the branch portion. The EGR lead-out pipe has a vertical wall portion disposed inside the cylindrical portion, and a cutout portion opened at an end surface on the EGR gas pipe side is provided in a portion of the vertical wall portion on the EGR gas pipe side. I have. For this reason, when the EGR gas flowing through the EGR gas pipe is supplied into the EGR lead-out pipe, the swirling flow of the EGR gas is suppressed by the notch in the vertical wall. When the EGR gas flows in the EGR outlet pipe, the vertical wall suppresses the drift of the EGR gas. Even if the EGR gas pipe is shortened in this way, the swirling flow and drift of the EGR gas are suppressed, so that the EGR gas can be evenly distributed to each bank.

  The end face of the vertical wall portion opposite to the EGR gas pipe is in contact with the inner wall of the branch pipe, and a gap is provided between the end face of the cylindrical portion opposite to the EGR gas pipe and the inner wall of the branch pipe. May be provided. In such a configuration, since the end surface of the vertical wall portion on the side opposite to the EGR gas pipe is in contact with the inner wall of the branch pipe, the vertical wall portion becomes long. Therefore, when the EGR gas flows through the inside of the EGR outlet pipe, the drift of the EGR gas is sufficiently suppressed by the vertical wall portion. Further, since a gap is provided between the end surface of the cylindrical portion opposite to the EGR gas pipe and the inner wall of the branch pipe, the end surface of the vertical wall opposite to the EGR gas pipe is formed of the branch pipe. Even when the EGR gas is in contact with the inner wall, the EGR gas flowing through each passage in the EGR outlet pipe is surely guided into each branch pipe.

  The notch may have a rectangular shape. In such a configuration, incomplete combustion products and the like contained in the EGR gas are unlikely to deposit on the bottom of the notch.

  The connection part of the intake pipe with the branch part is located above the connection part of the EGR gas pipe with the branch part, and the air flowing through the intake pipe is divided into two parts above the EGR outlet pipe in the branch part. A rectifying wall having an inverted V-shaped cross section may be arranged to be guided into the pipe. In such a configuration, the air flowing in the intake pipe is smoothly guided into each branch pipe along the straightening wall.

  According to the present invention, the EGR gas can be evenly distributed to each bank while shortening the EGR gas pipe.

1 is a plan view showing an engine including an intake device according to an embodiment of the present invention. FIG. 2 is a rear view including a partial cross section of the intake device shown in FIG. 1. FIG. 3 is a perspective view of the EGR outlet pipe shown in FIGS. 1 and 2. FIG. 4 is a rear view of the EGR outlet pipe shown in FIG. 3. FIG. 5 is a sectional view taken along line VV of FIG. 4. FIG. 4 is a side view of the EGR outlet pipe shown in FIG. 3. FIG. 7 is a side view showing a modification of the EGR lead-out pipe shown in FIG. 6.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements have the same reference characters allotted, and overlapping description will be omitted.

  FIG. 1 is a plan view showing an engine provided with an intake device according to one embodiment of the present invention. FIG. 2 is a rear view including a partial cross section of the intake device shown in FIG. 1 and 2, an engine 1 is a V-type six-cylinder diesel engine, which is mounted on a vehicle. The engine 1 includes a left bank 2A and a right bank 2B. That is, the engine 1 has two banks. The left bank 2A and the right bank 2B are three-cylinder banks.

  Further, the engine 1 has an intake passage 4 connected to the left bank 2A and the right bank 2B via intake manifolds 3A and 3B, and an exhaust gas connected to the left bank 2A and the right bank 2B via exhaust manifolds 5A and 5B. And a passage 6. The intake passage 4 is a passage through which air (fresh air) drawn into each cylinder of the left bank 2A and the right bank 2B flows. The exhaust passage 6 is a passage through which exhaust gas generated in each cylinder of the left bank 2A and the right bank 2B flows.

  Further, the engine 1 includes a turbocharger 7 for supercharging air. The turbocharger 7 has a turbine 8 arranged in the exhaust passage 6, a compressor 9 arranged in the intake passage 4, and a shaft 10 connecting the turbine 8 and the compressor 9. The turbine 8 rotates by receiving the flow of the exhaust gas. The compressor 9 compresses air using the torque of the turbine 8.

  On the downstream side of the compressor 9 in the intake passage 4, an intercooler 11 and a throttle valve 12 (omitted in FIG. 1) are arranged in order toward the left bank 2A and the right bank 2B. The intercooler 11 is a heat exchanger that cools air supercharged by the turbocharger 7. Intercooler 11 is arranged on right bank 2B. The throttle valve 12 adjusts the flow rate of air taken into the left bank 2A and the right bank 2B.

  Further, the engine 1 recirculates a part of the exhaust gas generated in the cylinders of the left bank 2A and the right bank 2B into the cylinders of the left bank 2A and the right bank 2B as EGR gas (exhaust recirculation gas). It has. The EGR unit 13 includes an EGR passage 14 connecting the exhaust passage 6 and the intake passage 4, an EGR valve 15 for adjusting a flow rate of EGR gas flowing from the exhaust passage 6 to the intake passage 4 through the EGR passage 14, and an EGR passage 14. And an EGR cooler 16 for cooling the EGR gas flowing through the EGR cooler 16. EGR valve 15 and EGR cooler 16 are arranged above left bank 2A.

  The intake device 20 of the present embodiment is a device that is provided in the engine 1 and sucks air and EGR gas into the left bank 2A and the right bank 2B, respectively. The intake device 20 includes an intake passage 4, an intercooler 11, a throttle valve 12, and an EGR unit 13.

  The intake passage 4 includes an intake pipe 21 connected to the intercooler 11, and two branch pipes 22A branched from the intake pipe 21 and connected to the left bank 2A and the right bank 2B via intake manifolds 3A and 3B, respectively. , 22B. The throttle valve 12 is arranged inside the intake pipe 21.

  The EGR passage 14 includes an EGR gas pipe 24 connecting the exhaust passage 6 and the EGR cooler 16, an EGR gas pipe (not shown) connecting the EGR cooler 16 and the EGR valve 15, an EGR valve 15 and the intake passage 4. And an EGR gas pipe 25 for connecting the The EGR gas pipe 25 extends in a curved manner between the EGR valve 15 and the intake passage 4.

  The EGR gas pipe 25 is connected to a branch section 26 where the intake pipe 21 and the branch pipes 22A and 22B are connected. That is, the branch portion 26 is a portion in the intake passage 4 where the intake pipe 21, the EGR gas pipe 25, and the branch pipes 22A and 22B are connected. The connection part of the intake pipe 21 with the branch part 26 is located above the connection part of the EGR gas pipe 25 with the branch part 26.

  In addition, the intake device 20 includes a rectifying wall 27 and an EGR outlet pipe 28 arranged in the branch portion 26. The rectifying wall 27 is disposed above the EGR outlet pipe 28 in the branch portion 26. The flow regulating wall 27 has an inverted V-shape in a cross section cut in a direction perpendicular to the front-rear direction. The flow regulating wall 27 guides the air flowing through the intake pipe 21 into the branch pipes 22A and 22B. The EGR outlet pipe 28 is connected to the EGR gas pipe 25. The EGR outlet pipe 28 guides the EGR gas flowing through the EGR gas pipe 25 into the branch pipes 22A and 22B.

  FIG. 3 is a perspective view of the EGR outlet pipe 28. FIG. 4 is a rear view of the EGR outlet pipe 28. FIG. 5 is a sectional view taken along line VV of FIG. FIG. 6 is a side view of the EGR outlet pipe 28.

  3 to 6, the EGR lead-out tube 28 has a tubular portion 30 and a vertical wall portion 31 disposed inside the tubular portion 30. The tubular portion 30 has a front end face 30a (an end face on the EGR gas pipe 25 side) and a rear end face 30b (an end face on the opposite side to the EGR gas pipe 25). The front end face 30a has a circular shape when viewed from the front. The rear end face 30b has a substantially elliptical shape in rear view. The rear end surface 30b is a tapered surface inclined with respect to the front end surface 30a.

  The vertical wall portion 31 is formed integrally with the tubular portion 30 so as to extend from the front end surface 30a to the rear end surface 30b in the axial direction of the tubular portion 30. The vertical wall portion 31 stands upright. The vertical wall portion 31 partitions a passage 32A communicating with the inside of the branch pipe 22A and a passage 32B communicating with the inside of the branch pipe 22B. The vertical wall portion 31 has a front end face 31a (an end face on the EGR gas pipe 25 side) and a rear end face 31b (an end face on the opposite side to the EGR gas pipe 25).

  A cutout portion 33 is formed in a portion of the vertical wall portion 31 on the front end face 31a side (the EGR gas pipe 25 side). The cutout portion 33 is arranged at a vertical center portion of the vertical wall portion 31. The notch 33 has a rectangular shape (square shape) in a side view when viewed from the left and right directions. The length L of the cutout portion 33 is, for example, about １ ／ to ３ of the entire length L0 of the vertical wall portion 31. The width W of the notch 33 is, for example, about １ ／ to １ ／ of the outer diameter R of the vertical wall 31.

  The rear end surface 31b of the vertical wall portion 31 is a tapered surface inclined with respect to the front end surface 31a of the vertical wall portion 31 corresponding to the rear end surface 30b of the tubular portion 30. Thereby, the EGR outlet pipe 28 in which the cylindrical portion 30 and the vertical wall portion 31 are integrated is easily manufactured.

  The upper portion of the rear end face 31b of the vertical wall portion 31 is in contact with the inner wall at the boundary between the branch pipes 22A and 22B (see FIG. 5). The rear end surface 30b of the cylindrical portion 30 is a tapered surface as described above. For this reason, a gap S is provided between the rear end surface 30b of the tubular portion 30 and the inner wall at the boundary between the branch pipes 22A and 22B (see FIG. 6). As a result, the EGR gas flowing in the EGR outlet pipe 28 is guided into the branch pipes 22A and 22B. The size of the gap S increases toward the lower side of the tubular portion 30.

  In the above-described intake device 20, when the air flowing through the intake pipe 21 is supplied to the branch portion 26, the air is guided along the rectifying wall 27 into the branch pipes 22A and 22B (see arrow X in FIG. 2). ). On the other hand, when the EGR gas flowing in the EGR gas pipe 25 is supplied to the branch portion 26, the EGR gas flows through the passages 32A and 32B in the EGR outlet pipe 28 and is guided to the branch pipes 22A and 22B (arrows in FIG. 2). Y). Then, the air and the EGR gas are mixed on the downstream side of the branch portion 26 in the branch pipes 22A and 22B, and are introduced into the left bank 2A and the right bank 2B, respectively.

  By the way, when the vertical wall portion 31 is not provided in the EGR outlet pipe 28 disposed in the branch portion 26 of the intake passage 4, the following problem occurs. That is, the opening and closing operation of the EGR valve 15 generates a swirling flow of the EGR gas flowing in the EGR gas pipe 25. At this time, if the EGR gas pipe 25 is short, the swirling flow of the EGR gas does not converge in the EGR gas pipe 25 and easily reaches the EGR derivation pipe 28. In addition, the EGR gas tends to drift in the EGR outlet pipe 28. This makes it difficult to evenly distribute the EGR gas to the left bank 2A and the right bank 2B.

  In order to solve such a problem, in the present embodiment, the EGR lead-out pipe 28 has a vertical wall portion 31 disposed inside the cylindrical portion 30, and a portion of the vertical wall portion 31 on the front end face 31 a side is provided. , A notch 33 opened in the front end face 31a. Therefore, when the EGR gas flowing through the EGR gas pipe 25 is supplied into the EGR outlet pipe 28, the swirling flow of the EGR gas is suppressed by the notch 33 of the vertical wall portion 31. Then, when the EGR gas flows through the inside of the EGR guide pipe 28, the vertical wall portion 31 suppresses the drift of the EGR gas. Thus, even if the EGR gas pipe 25 is shortened, the swirling flow and the drift of the EGR gas are suppressed, so that the EGR gas can be evenly distributed to the left bank 2A and the right bank 2B.

  As a result, variation in the EGR rate between the cylinders of the left bank 2A and the right bank 2B can be reduced. Therefore, PCCI combustion (premixed compression auto-ignition combustion) becomes possible, so that NOx can be reduced. Further, since the EGR gas pipe 25 is shortened, the size of the engine 1 can be reduced, which is advantageous in terms of space.

  In the present embodiment, since the rear end face 31b of the vertical wall portion 31 is in contact with the inner wall at the boundary between the branch pipes 22A and 22B, the vertical wall portion 31 is elongated. Therefore, when the EGR gas flows through the inside of the EGR outlet pipe 28, the drift of the EGR gas is sufficiently suppressed by the vertical wall portion 31. Further, since the gap S is provided between the rear end face 30b of the cylindrical portion 30 and the inner wall at the boundary between the branch pipes 22A and 22B, the rear end face 31b of the vertical wall section 31 is formed by the branch pipes 22A and 22B. Even if the EGR gas is in contact with the inner wall of the boundary, the EGR gas flowing through the passages 32A and 32B in the EGR outlet pipe 28 is surely guided into the branch pipes 22A and 22B, respectively.

  Further, in the present embodiment, since the notch 33 of the vertical wall portion 31 has a rectangular shape, incompletely combusted substances and the like contained in the EGR gas hardly accumulate on the bottom of the notch 33.

  Further, in the present embodiment, since the straightening wall 27 having an inverted V-shaped cross section is disposed above the EGR outlet pipe 28 in the branch portion 26, the air flowing in the intake pipe 21 flows along the straightening wall 27 along the straightening wall 27. It will be guided smoothly into 22A and 22B.

  Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, the shape of the rear end surface 31b of the vertical wall portion 31 is tapered in accordance with the shape of the rear end surface 30b of the cylindrical portion 30 in consideration of the manufacturability of the EGR lead-out tube 28. It is not limited to the form.

  FIG. 7 is a side view showing a modification of the EGR lead-out pipe 28 shown in FIG. In FIG. 7, the rear end surface 30 b of the cylindrical portion 30 is parallel to the front end surface 30 a of the cylindrical portion 30. The rear end surface 31b of the vertical wall portion 31 is parallel to the front end surface 31a of the vertical wall portion 31.

  The rear end of the vertical wall portion 31 protrudes from the rear end surface 30b of the tubular portion 30. The rear end face 31b of the vertical wall portion 31 is entirely in contact with the inner wall at the boundary between the branch pipes 22A and 22B. A gap S is provided between the rear end surface 30b of the tubular portion 30 and the inner wall at the boundary between the branch pipes 22A and 22B. The size of the gap S is constant in the vertical direction of the tubular portion 30. As a result, the EGR gas flowing through the passages 32A and 32B in the EGR outlet pipe 28 is reliably guided into the branch pipes 22A and 22B, respectively. Further, the rear end face 31b of the vertical wall portion 31 is entirely brought into contact with the inner wall at the boundary between the branch pipes 22A and 22B, whereby the movement of the EGR gas between the left bank 2A and the right bank 2B is prevented. Therefore, the influence on the combustion operation of the left bank 2A and the right bank 2B can be reduced.

  Further, in the above embodiment, the notch 33 of the vertical wall portion 31 has a rectangular shape in a side view, but the shape of the notch 33 is not particularly limited to a rectangular shape, and may be a square (square). Or a triangular or trapezoidal shape.

  Further, in the above embodiment, the tubular portion 30 and the vertical wall portion 31 of the EGR lead-out pipe 28 are formed integrally. However, the present invention is not particularly limited to this, and the tubular portion 30 and the vertical wall portion 31 are separately provided. It may be formed of a body.

  Further, in the above embodiment, the engine 1 is a V-type six-cylinder engine, but the type of the engine 1 is not particularly limited to the V-type engine as long as it has two banks. Further, the number of cylinders of the engine 1 is not particularly limited to six cylinders.

  Further, in the above embodiment, the engine 1 is a diesel engine. However, the present invention is not particularly limited to the diesel engine, and is applicable to a gasoline engine.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2A ... Left bank (bank), 2B ... Right bank (bank), 20 ... Intake device, 21 ... Intake pipe, 22A, 22B ... Branch pipe, 25 ... EGR gas pipe, 26 ... Branch part, 27 ... Rectifying wall, 28 EGR outlet pipe, 30 tubular part, 30b rear end face, 31 vertical wall part, 31a front end face, 31b rear end face, 32A, 32B passage, 33 notch.

Claims (4)

An intake device for an engine, provided in an engine having two banks, for inhaling air and EGR gas into the two banks, respectively.
An intake pipe through which the air flows,
Two branch pipes branched from the intake pipe and connected to the two banks, respectively;
An EGR gas pipe connected to a branch part where the intake pipe and the branch pipe are connected, and through which the EGR gas flows;
An EGR outlet pipe that is arranged in the branch section and guides the EGR gas flowing through the EGR gas pipe into the two branch pipes, respectively.
The EGR lead-out pipe has a tubular portion, and a vertical wall portion that is disposed inside the tubular portion and partitions two passages that are respectively connected to the two branch pipes,
An intake device for an engine, wherein a cutout portion that is opened at an end surface on the EGR gas pipe side is provided in a portion of the vertical wall on the EGR gas pipe side. An end surface of the vertical wall portion opposite to the EGR gas pipe is in contact with an inner wall of the branch pipe,
The engine intake device according to claim 1, wherein a gap is provided between an end surface of the cylindrical portion opposite to the EGR gas pipe and an inner wall of the branch pipe.   The intake device for an engine according to claim 1, wherein the notch has a rectangular shape. A connection portion of the intake pipe with the branch portion is located above a connection portion of the EGR gas pipe with the branch portion,
4. A rectifying wall having an inverted V-shaped cross section that guides the air flowing through the intake pipe into the two branch pipes, respectively, is disposed above the EGR outlet pipe in the branch portion. An intake device for an engine according to claim 1.

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