JP6699439B2 - Engine exhaust gas recirculation system - Google Patents

Description

  The present invention relates to an engine exhaust gas recirculation system.

  In a vehicle such as an automobile, an engine is provided with an intake manifold, and a downstream end of the intake manifold in the intake flow direction is connected to a side surface of the cylinder head so as to communicate with an intake port of the cylinder head. ..

  In the engine configured as described above, the intake manifold vibrates by vibrating from the vehicle body or the engine with the connecting portion with the cylinder head as a fulcrum. If the intake manifold vibrates, comfort may be impaired, and durability of constituent members of the intake manifold such as the intake pipe may be impaired.

  On the other hand, the technique described in Patent Document 1 is known. The device described in Patent Document 1 is designed to reduce the vibration of the intake manifold by supporting the intake manifold on the engine by a stiffener.

  On the other hand, in vehicles such as automobiles, an engine is provided with an exhaust gas recirculation device, and the exhaust gas recirculation device recirculates exhaust gas to an intake manifold. The technology described in Patent Document 2 is known as this type of exhaust gas recirculation device. The one described in Patent Document 2 includes an exhaust gas recirculation pipe that recirculates exhaust gas to an intake manifold, and an EGR cooler provided in the middle of the exhaust gas recirculation pipe. The EGR cooler is arranged below the intake pipe. Moreover, an EGR cooler is attached to the bracket that supports the intake pipe. According to the technique described in Patent Document 2, since both the EGR cooler and the intake pipe are supported by the bracket, it can be expected to make the intake and exhaust devices compact.

JP-A-11-50923 JP, 2008-180173, A

  However, the one described in Patent Document 1 has a problem that the addition of the stiffener causes an increase in engine weight. Further, in the devices described in Patent Documents 1 and 2, it is necessary to significantly increase the rigidity of the stiffener or the bracket in order to sufficiently suppress the vibration of the intake pipe, and the weight of the stiffener or the bracket is increased. There was a problem that is causing.

  The present invention has been made in view of the above-mentioned problems, and provides an exhaust gas recirculation device for an engine, which is capable of enhancing the effect of suppressing the vibration of the intake manifold and reducing the weight of the engine. The purpose is.

  The present invention is directed to a cylinder head arranged above a cylinder block, an intake manifold connected to the cylinder head, an exhaust gas recirculation pipe for recirculating exhaust gas to an intake passage of the intake manifold, and an intermediate part of the exhaust gas recirculation pipe. And an EGR cooler that is arranged in the intake manifold, the intake manifold is curved from the cylinder head and extends downward, and a peripheral portion of an upstream end of the intake manifold in the intake flow direction is arranged laterally of the cylinder block. In the exhaust gas recirculation device for an engine, the intake manifold has an exhaust gas introduction port for introducing exhaust gas on a wall surface of the upstream end peripheral portion facing the cylinder block, and the EGR cooler includes the cylinder block. Is fixed to the outer wall of the exhaust gas, the EGR cooler has an exhaust gas outlet opening toward a space sandwiched between the upstream end peripheral portion and the outer wall of the cylinder block, and the exhaust gas recirculation pipe is connected to the exhaust gas outlet. It is characterized in that it has an L-shaped curved cooler outlet side exhaust gas recirculation pipe that is connected to the exhaust gas introduction port.

  As described above, according to the present invention, it is possible to enhance the effect of suppressing the vibration of the intake manifold and to reduce the weight of the engine.

FIG. 1 is a front view of an engine including an exhaust gas recirculation device according to an embodiment of the present invention. FIG. 2 is a sectional view taken along the line II-II of FIG. FIG. 3 is a sectional view taken along the line III-III of FIG.

  An engine exhaust gas recirculation system according to an embodiment of the present invention includes a cylinder head arranged above a cylinder block, an intake manifold connected to the cylinder head, and an exhaust gas recirculating exhaust gas to an intake passage of the intake manifold. The intake manifold includes a recirculation pipe and an EGR cooler disposed in the middle of the exhaust recirculation pipe, the intake manifold is curved from the cylinder head and extends downward, and a peripheral portion of an upstream end of the intake manifold in the intake flow direction is a cylinder block. In the exhaust gas recirculation device for an engine arranged laterally, the intake manifold has an exhaust gas introduction port for introducing exhaust gas on a wall surface facing the cylinder block in the periphery of the upstream end, and the EGR cooler includes the cylinder block. The EGR cooler has an exhaust gas outlet opening toward the space sandwiched between the upstream end peripheral portion and the outer wall of the cylinder block, and the exhaust gas recirculation pipe includes an exhaust gas outlet and an exhaust gas introduction port. It is characterized by having an L-shaped curved cooler outlet side exhaust gas recirculation pipe that connects the. As a result, the exhaust gas recirculation device for an engine according to the embodiment of the present invention can enhance the effect of suppressing the vibration of the intake manifold and reduce the weight of the engine.

  An exhaust gas recirculation system for an engine according to an embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are views showing an exhaust gas recirculation system for an engine according to an embodiment of the present invention. 1 to 3, the up, down, left, and right directions indicate the directions viewed from the driver who gets on the vehicle.

  First, the configuration will be described. In FIG. 1, an engine 10 is a four-cylinder engine in which four cylinders are arranged in series, and is placed horizontally in an engine room of a vehicle (not shown) so that a cylinder row direction indicated by an arrow A is a lateral direction of the vehicle. It is arranged.

  The engine 10 includes a cylinder block 13, a cylinder head 14 provided above the cylinder block 13, a cylinder head cover 15 closing an upper end of the cylinder head 14, and a cylinder block 13 provided below the cylinder block 13. And bread 16. The cylinder block 13, the cylinder head 14, the cylinder head cover 15, and the oil pan 16 constitute the engine body 11.

  In FIG. 2, a plurality of cylinders 13B is formed in the cylinder block 13, and a piston 13C (not shown) is reciprocally housed in the cylinder 13B, and the reciprocating motion of the piston 13C is housed in the cylinder block 13. It is converted into the rotational movement of the crankshaft 13D (not shown).

  A plurality of intake ports 14A and exhaust ports 14B are formed in the cylinder head 14, and the intake ports 14A and the exhaust ports 14B communicate with a combustion chamber (not shown) of the cylinder head 14.

  In FIGS. 1, 2 and 3, an intake manifold 20 is connected to the rear side surface of the cylinder head 14 with bolts, and the intake manifold 20 is curved from the cylinder head 14 and extends downward. An intake passage 20A is formed inside the intake manifold 20, and air flows in the intake passage 20A in the intake flow direction indicated by arrow B. The intake manifold 20 is branched on the downstream side in the intake air flow direction, and distributes the air passing through the intake passage 20A to the intake ports 14A of each cylinder. An upstream end peripheral portion 21 of the intake manifold 20 in the intake flow direction is arranged laterally of the cylinder block 13.

  The intake manifold 20 includes a surge tank 24 immediately before the branch point in the intake passage 20A. The surge tank 24 has a larger passage cross-sectional area than the other portions of the intake passage 20A, and temporarily stores the air introduced into the intake manifold 20 before supplying it to the intake port 14A of each cylinder. ..

  The engine 10 is also provided with an intake pipe 19, and the intake pipe 19 introduces the air filtered through an air cleaner (not shown) into the intake manifold 20.

  The intake pipe 19 extends rearward from the front of the engine body 11 through the vicinity of the right side surface of the engine body 11. Then, the intake pipe 19 sequentially extends to the left and the upper left in the rear of the engine body 11 so as to pass below the alternator 17 arranged on the right end side of the rear surface of the engine body 11, and the intake manifold 20 It is connected to the upstream end in the intake air flow direction. The intake pipe 19 is made of a soft material such as rubber. Further, the intake pipe 19 has a divided structure divided into parts.

  The engine 10 is provided with an exhaust gas recirculation device 30. The exhaust gas recirculation device 30 includes an exhaust gas recirculation pipe 31 that recirculates exhaust gas to the intake passage 20A of the intake manifold 20, and an EGR disposed in the middle of the exhaust gas recirculation pipe 31. And a cooler 35. The exhaust gas recirculation pipe 31 and the EGR cooler 35 are arranged on the rear side surface of the cylinder block 13. Exhaust gas flows through the exhaust gas recirculation pipe 31 and the EGR cooler 35 in the exhaust gas flow direction indicated by arrow C.

  The EGR cooler 35 includes a tubular body portion 35C, an exhaust gas inlet 35A provided at an upstream end of the body portion 35C in the exhaust flow direction, and an exhaust gas outlet provided at a downstream end of the body portion 35C in the exhaust flow direction. 35B. The EGR cooler 35 cools the exhaust gas by exchanging heat with the cooling water flowing through the main body portion 35C. Since the main body portion 35C of the EGR cooler 35 is tubular, the length of the installation space for the EGR cooler 35 is required. For this reason, the EGR cooler 35 is a space to the left of the starter 18 arranged on the left end side of the rear surface of the engine body 11 and generally in a space below the connecting portion between the intake manifold 20 and the cylinder head 14. It is placed in a horizontal position.

  The exhaust gas recirculation pipe 31 includes a cooler inlet side exhaust gas recirculation pipe 32 connected to an upstream side of the EGR cooler 35 in the exhaust gas flow direction and a cooler outlet side exhaust gas recirculation pipe 33 connected to a downstream side of the EGR cooler 35 in the exhaust gas flow direction. Have and.

  Exhaust gas exhausted from the exhaust port 14B is supplied to the cooler inlet side exhaust gas recirculation pipe 32 through a recirculation pipe (not shown) provided outside the cylinder head 14 or a recirculation passage formed inside the cylinder head 14. be introduced.

  In this embodiment, the intake manifold 20 has an exhaust gas introduction port 22 on a wall surface 21A facing the cylinder block 13 in the upstream end peripheral portion 21, and the exhaust gas introduction port 22 introduces the exhaust gas into the intake passage 20A. Will be introduced.

  The intake manifold 20 has an attachment portion 23, to which the cooler outlet side exhaust gas recirculation pipe 33 is fastened by a fastening member 41, outside the exhaust gas introduction port 22. Further, when the intake manifold 20 is viewed from the side opposite to the outer wall 13A of the cylinder block 13, the mounting portion 23 has a protruding portion 23A which protrudes outward from both widthwise side portions of the upstream end peripheral portion 21 of the intake manifold 20. . A seating surface 23B on which the fastening member 41 is seated is formed on the projecting portion 23A.

  The surge tank 24 is arranged downstream of the exhaust gas introduction port 22 in the intake manifold 20 in the intake flow direction, and extends in the cylinder row direction of the engine 10.

  When the virtual plane VP that extends in the vertical direction through the center of the surge tank 24 in the cylinder row direction is set, the exhaust gas introduction port 22 is located at a position that is biased to one side (right side) with respect to the virtual plane VP. It is arranged. The EGR cooler 35 is fixed to the cylinder block 13 so that the exhaust gas inlet 35A is located on the other side (left side) with respect to the virtual plane VP.

  The EGR cooler 35 is fixed to the outer wall 13</b>A of the rear surface of the cylinder block 13 via an EGR cooler bracket 37. The EGR cooler 35 is arranged in a posture inclining downward and to the right. The exhaust gas outlet 35B is open toward the space S sandwiched between the upstream end peripheral portion 21 and the outer wall 13A of the cylinder block 13.

The cooler outlet side exhaust gas recirculation pipe 33 is curved in an L-shape and connects the exhaust gas outlet 35B and the exhaust gas inlet 22. The cooler outlet side exhaust gas recirculation pipe 33 has a flange 33A on the exhaust gas outlet 35B side, and is connected to the exhaust gas outlet 35B by this flange 33A. The cooler outlet side exhaust gas recirculation pipe 33 has a flange 33B on the exhaust gas introducing port 22 side, and is connected to the exhaust gas introducing port 22 by this flange 33B.
The cooler outlet side exhaust gas recirculation pipe 33 extends downward and rightward from the flange 33A, then curves 90° rearward, and further extends rearward.

  The cooler outlet side exhaust gas recirculation pipe 33 has a single curved portion 33C. In the cooler outlet side exhaust gas recirculation pipe 33, the pipe length L1 between the intermediate position of the curved portion 33C and the exhaust gas outlet 35B is set shorter than the pipe length L2 between the intermediate position of the curved portion 33C and the exhaust gas inlet 22. Has been done.

  The cooler outlet side exhaust gas recirculation pipe 33 is made of a cylindrical metal. Specifically, the cooler outlet side exhaust gas recirculation pipe 33 is composed of a metal partial bellows pipe and a straight pipe, and is subjected to bellows-like bellows processing from the curved portion 33C to the exhaust gas outlet 35B. Further, in the cooler outlet side exhaust gas recirculation pipe 33, a portion extending from the curved portion 33C to the exhaust gas introduction port 22 is a straight pipe without bellows processing. That is, the cooler outlet side exhaust gas recirculation pipe 33 is configured to start bending from the flange 33A that is the upstream end in the intake air flow direction and to become the bending portion 33C up to the vicinity of the flange 33A. As a result, the length of the portion of the cooler outlet side exhaust gas recirculation pipe 33 having the pipe length L1 can be made as short as possible, so that this portion can be suppressed from vibrating in the vehicle longitudinal direction. Further, since the straight pipe portion in the portion having the pipe length L2 does not expand and contract, the rigidity of the cooler outlet side exhaust gas recirculation pipe 33 in the vehicle front-rear direction can be further increased.

  Next, the operation will be described. The intake manifold 20 receives the vibration generated in the engine 10 or the vibration accompanying the traveling of the vehicle, and vibrates with the connecting portion with the cylinder head 14 as a fixed end. Therefore, the intake manifold 20 is likely to vibrate in a direction intersecting with the outer wall 13A of the cylinder block 13, that is, in the front-rear direction, at the upstream end peripheral portion 21 farthest from the connecting portion to the cylinder head 14.

  In the present embodiment, the intake manifold 20 has an exhaust gas introduction port 22 for introducing exhaust gas on a wall surface 21A of the upstream end peripheral portion 21 facing the cylinder block 13. Further, the EGR cooler 35 is fixed to the outer wall 13A of the cylinder block 13.

  Further, the EGR cooler 35 has an exhaust gas outlet 35B that opens toward the space S sandwiched between the upstream end peripheral portion 21 and the outer wall 13A of the cylinder block 13. Further, the exhaust gas recirculation pipe 31 has a cooler outlet side exhaust gas recirculation pipe 33 that is curved in an L shape and connects the exhaust gas outlet 35B and the exhaust gas introduction port 22.

  With this configuration, the EGR cooler 35 can be fixed to the outer wall 13A of the cylinder block 13 so as to shorten the distance between the exhaust gas inlet 22 of the intake manifold 20 and the exhaust gas outlet 35B of the EGR cooler 35.

  Then, the exhaust gas outlet 35B of the EGR cooler 35 and the exhaust gas inlet 22 of the intake manifold 20 can be connected by a cooler outlet side exhaust gas recirculation pipe 33 which has a closed cross section and is curved in an L shape and has a short overall length.

  This allows the cooler outlet side exhaust gas recirculation pipe 33 to function as a stiffener, and ensures that the upstream end peripheral portion 21 of the intake manifold 20 vibrates in the direction intersecting the outer wall 13A of the cylinder block 13 (front-back direction). It can be prevented.

  Further, in the present embodiment, the vibration of the intake manifold 20 can be suppressed without using a stiffener, so that the weight of the engine can be reduced.

  As a result, the effect of suppressing the vibration of the intake manifold can be enhanced and the weight of the engine can be reduced.

  Further, in this embodiment, the cooler outlet side exhaust gas recirculation pipe 33 has a single curved portion 33C, and the cooler outlet side exhaust gas recirculation pipe 33 is disposed between the intermediate position of the curved portion 33C and the exhaust gas outlet 35B. The pipe length L1 is set shorter than the pipe length L2 between the intermediate position of the curved portion 33C and the exhaust gas introduction port 22.

  With this configuration, the pipe length L1 between the intermediate position of the curved portion 33C of the cooler outlet side exhaust gas recirculation pipe 33 and the exhaust gas outlet 35B can be shortened, so that the cooler outlet side exhaust gas recirculation pipe 33 can be made difficult to vibrate in the vehicle longitudinal direction. The vibration suppressing effect of the intake manifold 20 can be enhanced.

  Further, in the present embodiment, the intake manifold 20 has the mounting portion 23 to which the cooler outlet side exhaust gas recirculation pipe 33 is fastened by the fastening member 41, outside the exhaust gas introduction port 22. When the intake manifold 20 is viewed from the side opposite to the outer wall 13A of the cylinder block 13, the mounting portion 23 has a protruding portion 23A that protrudes outward from both widthwise side portions of the upstream end peripheral portion 21 of the intake manifold 20. A seat surface 23B on which the fastening member 41 is seated is formed on the protruding portion 23A.

  With this configuration, the flange 33B of the cooler outlet side exhaust gas recirculation pipe 33 can be fastened to the attachment portion 23 on the intake manifold 20 side from the side opposite to the outer wall 13A of the cylinder block 13 with respect to the intake manifold 20.

  In addition, it is not necessary to secure a space for fastening work between the upstream end peripheral portion 21 of the intake manifold 20 and the outer wall 13A of the cylinder block 13, and the upstream end peripheral portion 21 of the intake manifold 20 is made to be closer to the outer wall of the cylinder block 13. It can approach 13A.

  Therefore, the pipe length L1 of the cooler outlet side exhaust gas recirculation pipe 33 can be further shortened, and the vibration suppressing effect of the intake manifold 20 can be enhanced.

  Further, in the present embodiment, the intake manifold 20 has the surge tank 24 extending in the cylinder column direction A of the engine 10 on the downstream side of the exhaust gas introduction port 22 in the intake flow direction. When the virtual plane VP extending in the vertical direction through the center of the surge tank 24 in the cylinder row direction is set, the exhaust gas introduction port 22 is arranged at a position deviated to one side with respect to the virtual plane VP. There is.

  With this configuration, the space below the surge tank 24 and on the virtual plane VP side in the cylinder column direction A from the exhaust gas introduction port 22 is larger than the opposite side.

  Further, in this embodiment, the EGR cooler 35 includes a cylindrical main body portion 35C, an exhaust gas inlet 35A provided at an upstream end of the main body portion 35C in the exhaust flow direction, and a downstream end of the main body portion 35C in the exhaust flow direction. And an exhaust gas outlet 35B provided in the. Further, the EGR cooler 35 is fixed to the cylinder block 13 so that the exhaust gas inlet 35A is located on the other side with respect to the virtual plane VP.

  With this configuration, even in the case of the EGR cooler 35 in which the distance between the exhaust gas inlet 35A and the exhaust gas outlet 35B is long, it is easy to bring the exhaust gas outlet 35B close to the exhaust gas inlet 22 of the intake manifold 20.

  Further, in this embodiment, the cooler outlet side exhaust gas recirculation pipe 33 is made of a cylindrical metal.

  With this configuration, since the cooler outlet side exhaust gas recirculation pipe 33 is made of a cylindrical metal, it is possible to provide sufficient strength even if the cooler outlet side exhaust gas recirculation pipe 33 is formed thin. Further, since the cooler outlet side exhaust gas recirculation pipe 33 has a cylindrical shape, there is no fear that noise or vibration will be deteriorated depending on the vibration direction unlike a conventional planar stiffener made of a sheet metal or the like.

  Further, in this embodiment, the cooler outlet side exhaust gas recirculation pipe 33 is a partial bellows pipe in which only the portion extending from the curved portion 33C to the exhaust gas outlet 35B is bellows processed.

  With this configuration, the portion of the cooler outlet side exhaust gas recirculation pipe 33 that extends from the curved portion 33C to the exhaust gas introduction port 22 becomes a straight pipe that is not subjected to bellows processing. Therefore, the rigidity of the cooler outlet side exhaust gas recirculation pipe 33 in the direction intersecting the outer wall 13A of the cylinder block 13 (front-rear direction) can be increased. Therefore, it is possible to more effectively suppress the upstream end peripheral portion 21 of the intake manifold 20 from vibrating in the direction intersecting the outer wall 13A of the cylinder block 13 (front-rear direction).

  While an embodiment of this invention has been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of this invention. All such modifications and equivalents are intended to be included in the following claims.

10... Engine, 13... Cylinder block, 13A... Outer wall, 14... Cylinder head, 20... Intake manifold, 20A... Intake passage, 21... Upstream end peripheral part, 21A ...Wall surface, 22...exhaust gas inlet, 23...mounting part, 23A...projection part, 23B...seat surface, 24...surge tank, 30...exhaust gas recirculation device, 31... Exhaust gas recirculation pipe, 33... Cooler outlet side exhaust gas recirculation pipe, 33C... Curved portion, 35... EGR cooler, 35A... Exhaust gas inlet, 35B... Exhaust gas outlet, 35C ... body part, 41... fastening member, A... cylinder row direction, B... intake flow direction, C... exhaust flow direction, L1... pipe length (intermediate position of curved part and exhaust Pipe length between gas outlet), L2 (pipe length between middle position of curved portion and exhaust gas inlet)...pipe length, S...space, VP...virtual plane

Claims (6)

A cylinder head arranged on the top of the cylinder block,
An intake manifold connected to the cylinder head;
An exhaust gas recirculation pipe for recirculating exhaust gas to the intake passage of the intake manifold;
An EGR cooler arranged in the middle of the exhaust gas recirculation pipe,
In the exhaust gas recirculation device for an engine, wherein the intake manifold curves downward from the cylinder head and extends downward, and a peripheral portion of an upstream end of the intake manifold in an intake flow direction is arranged laterally of the cylinder block,
The intake manifold has an exhaust gas introduction port for introducing exhaust gas on a wall surface facing the cylinder block in the peripheral portion of the upstream end,
The EGR cooler is fixed to the outer wall of the cylinder block,
The EGR cooler has an exhaust gas outlet opening toward a space sandwiched between the upstream end peripheral portion and the outer wall of the cylinder block,
The exhaust gas recirculation device for an engine, wherein the exhaust gas recirculation pipe includes a cooler outlet side exhaust gas recirculation pipe that is curved in an L shape and connects the exhaust gas outlet and the exhaust gas introduction port. The cooler outlet side exhaust gas recirculation pipe has a single curved portion,
In the cooler outlet side exhaust gas recirculation pipe, the pipe length between the intermediate position of the curved portion and the exhaust gas outlet is set shorter than the pipe length between the intermediate position of the curved portion and the exhaust gas introduction port. The exhaust gas recirculation device for an engine according to claim 1, wherein: The intake manifold has an attachment portion, on the outside of the exhaust gas inlet, at which the cooler outlet side exhaust gas recirculation pipe is fastened by a fastening member,
When the intake manifold is viewed from the side opposite to the outer wall of the cylinder block,
The mounting portion has a protrusion protruding outward from both widthwise side portions of the upstream end peripheral portion of the intake manifold,
The exhaust gas recirculation device for an engine according to claim 1, wherein a seating surface on which the fastening member is seated is formed on the protrusion. The intake manifold has a surge tank extending in the cylinder row direction of the engine on the downstream side in the intake flow direction from the exhaust gas introduction port,
When setting a virtual plane that extends in the vertical direction through the center portion of the cylinder row direction in the surge tank, the exhaust gas introduction port is arranged at a position biased to one side with respect to the virtual plane,
The EGR cooler includes a cylindrical main body, an exhaust gas inlet provided at an upstream end of the main body in the exhaust flow direction, and an exhaust gas outlet provided at a downstream end of the main body in the exhaust flow direction. Have
The exhaust gas recirculation device for an engine according to claim 1, wherein the EGR cooler is fixed to the cylinder block so that the exhaust gas inlet is located on the other side with respect to the virtual plane.   The exhaust gas recirculation device for an engine according to any one of claims 1 to 4, wherein the cooler outlet side exhaust gas recirculation pipe is made of a cylindrical metal. The engine exhaust according to claim 2 , wherein the cooler outlet side exhaust gas recirculation pipe is a metal partial bellows pipe that is bellows-processed only in a portion extending from the curved portion to the exhaust gas outlet. Reflux device.

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