JP5561554B2 - Intake device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake device for an internal combustion engine, and more particularly to an improvement in a configuration in which part of exhaust gas is reduced to an intake pipe that sends air to a combustion chamber of the internal combustion engine.

  As an intake device for an internal combustion engine configured as described above, Patent Document 1 discloses that a metal EGR guide pipe is inserted into a through hole of a resin intake manifold, and the intake manifold is inserted from the tip of the EGR pipe. A configuration for sending EGR gas into the interior is shown. In Patent Document 1, the tip of the EGR pipe is curved so as to be parallel to the flow direction of air sent to the intake manifold, and is configured to send out EGR gas in the flow direction of air sent to the intake manifold. .

  Patent Document 2 shows a configuration in which the tip of a metal EGR pipe is connected to a resin intake manifold by an EGR pipe joint structure, and EGR gas is sent from the tip of the EGR pipe into the intake manifold. Has been. In this Patent Document 2, the EGR pipe joint structure includes an enclosing tube that covers the outside of the EGR pipe tip insertion portion, a flange is formed on the enclosing tube, and an EGR pipe is inserted into the insertion port of the intake manifold. The EGR pipe is configured to be fixed to the intake manifold by a flange.

JP 2000-161161 A JP 2004-3320676 A

In the configuration shown in Patent Document 1, the exhaust gas discharged from the exhaust gas supply pipe is not directly blown against the intake manifold. However, since the intake manifold may receive the heat of the exhaust gas discharged from the supply pipe due to the flow of air taken from the outside, there is room for improvement, particularly when the intake manifold is made of resin.
Similarly, in the configuration shown in Patent Document 2, the exhaust gas discharged from the EGR pipe is not directly blown against the intake manifold. However, since the intake manifold may receive heat from the exhaust gas discharged from the EGR pipe due to the flow of air taken from the outside, there is room for improvement, particularly when the intake manifold is made of resin.

  It is also important that the EGR gas is well mixed with the air supplied to the engine combustion chamber. On the other hand, as shown in Patent Documents 1 and 2, there is room for improvement because it is difficult to obtain sufficient mixing in a configuration in which EGR gas is simply sent out from the end of an EGR pipe or EGR pipe.

  An object of the present invention is to rationally configure an intake device that can mix exhaust gas well with air sent to the intake pipe while suppressing inconvenience of damaging the intake pipe that sends air to the internal combustion engine due to the heat of the exhaust gas. is there.

A feature of the present invention is that a duct for sending the exhaust gas to the inside of the intake pipe as an exhaust gas reducing means for reducing a part of the exhaust gas of the internal combustion engine in a resin intake pipe for sending air to the combustion chamber of the internal combustion engine And a diffuser for sending exhaust gas sent from the duct to the inside of the intake pipe, and the duct is inserted into the intake pipe from an insertion opening formed in a wall surface of the intake pipe, and the diffuser Is formed with an internal space having a wall portion that prevents the exhaust gas sent from the end of the duct from directly contacting the inner wall of the intake pipe, and the exhaust gas received in the internal space of the intake pipe is the outlet for delivering diffused therein forming the diffuser is in that it is formed in a shape that a pointed end portion of the upstream side in the flow direction of air in the intake pipe

According to this configuration, the exhaust gas is sent from the duct to the diffuser, and is sent out in a state of diffusing from the outlet of the diffuser into the intake pipe. In addition, when exhaust gas is sent from the duct to the diffuser, the wall of the diffuser prevents the exhaust gas from directly contacting the inner wall of the intake pipe.
Therefore, the inconvenience of damaging the intake pipe that sends air to the internal combustion engine due to the heat of the exhaust gas is suppressed, and the inconvenience that deposits mainly composed of unburned hydrocarbons and oil mist contained in the exhaust gas are attached to the intake pipe is suppressed. However, an intake device that can mix exhaust gas well with the air sent to the intake pipe has been rationally constructed. In particular, in the present invention, since the diffuser is connected to the tip of the duct, the cross-sectional area of the discharge port is increased by connecting a diffuser having a larger diameter than the duct, and the contact area with the air sent to the intake pipe Expand to reveal good mixing.
In particular, the air flow in the intake pipe is guided to the side surface of the diffuser at the sharp end of the diffuser, and there is no inconvenience that the air flow is suppressed, and air can be sent smoothly to the intake pipe. It becomes possible.

  In the present invention, the exhaust port of the diffuser may include a diffusion unit that diffuses the exhaust gas by disturbing the flow of the exhaust gas sent out from the internal space.

  According to this, exhaust gas is diffused by the diffusing part and is sent out into the intake pipe, resulting in vortex flow, etc., and good mixing by disturbing the flow of the mixed gas sent from the diffusing part and air Realize.

  In the present invention, a plurality of legs that contact the inner surface of the intake pipe may be provided on the outer surface of the diffuser in order to hold the diffuser at the center position of the cross section of the intake space of the intake pipe.

  According to this, since the diffuser is held at the center position of the cross section of the intake space of the intake pipe by the plurality of legs, uneven mixing of the exhaust gas in the cross section of the intake space of the intake pipe is suppressed, and a better mixing state Appears. In addition, since the air flowing through the intake pipe contacts the legs and removes heat, the diffuser performs good heat dissipation, and there are problems such as using a heat-resistant material and a heat insulating material for the intake pipe. Eliminate.

  According to the present invention, the diffuser has a size of a cross-sectional area of an upstream inlet in the air flow direction in the intake pipe and a size of a cross-sectional area of a discharge port downstream in the air flow direction of the intake pipe. Differently, the duct may be connected to the portion on the discharge port side in a communicating state.

  According to this, the flow rate of air when the air flowing in from the inlet of the diffuser flows out of the discharge port is different from the flow rate of the air flowing outside the diffuser. When the gas is sent out from the outlet, the air flow is disturbed due to the difference in speed, and the mixing is promoted, and good mixing appears.

  In the present invention, the intake pipe constitutes an intake manifold connected to the internal combustion engine on the downstream side in the air flow direction, and a throttle valve for controlling the air amount is connected on the upstream side in the air flow direction. The diffuser may be connected to the end of the duct inserted through the insertion opening after being inserted into the intake pipe from the opening connected to the throttle valve.

  According to this, when the intake device is assembled, the duct is inserted into the insertion opening of the intake pipe, the diffuser is inserted from the opening to which the throttle valve is connected, and this diffuser is connected to the tip of the duct. Thereby, it is not only necessary to form a large opening through which the diffuser can be inserted into the intake pipe, and an intake device having a structure in which the outer diameter of the diffuser is larger than the insertion opening of the intake pipe can be configured.

It is a top view of the diesel engine provided with the EGR device of a 1st embodiment. It is sectional drawing of the intake pipe of 1st Embodiment. It is a longitudinal section of the EGR device of a 1st embodiment. It is a cross-sectional view of the EGR device of the first embodiment. It is a longitudinal cross-sectional view of the EGR apparatus of 2nd Embodiment. It is a longitudinal cross-sectional view of the EGR apparatus of 3rd Embodiment. It is a longitudinal cross-sectional view of the EGR apparatus of 4th Embodiment. It is a longitudinal cross-sectional view of the EGR apparatus of 5th Embodiment. It is a perspective view of the EGR device of a 6th embodiment. It is a longitudinal cross-sectional view of the EGR apparatus of 7th Embodiment. It is a longitudinal cross-sectional view of the EGR apparatus of 8th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows a diesel engine E as an internal combustion engine provided with an intake device. The diesel engine E includes an intake air amount control system that controls the amount of air supplied to the combustion chamber by a throttle valve A, and a fuel supply system that supplies fuel to the combustion chamber by an injector (not shown). An EGR (Exhaust Gas Recirculation) device B is provided as exhaust gas reduction means for reducing part of the exhaust gas in the exhaust path to the intake path.

  The EGR device B is for reducing a part of the exhaust gas to the combustion chamber. In particular, in the diesel engine E, the combustion temperature is lowered by mixing exhaust gas containing water vapor and carbon dioxide as main components of the exhaust gas into the intake air. And has a function of reducing the amount of NOx produced.

  A resin intake manifold 2 for supplying air to the combustion chamber via an intake valve (not shown) is connected to one side surface of the cylinder head 1 of the diesel engine E, and the other side surface of the cylinder head 1 is connected to the other side surface. A metal exhaust manifold 3 for sending exhaust gas discharged from the combustion chamber through an exhaust valve (not shown) is connected. The intake manifold 2 has a surge space 21 for supplying air from a single intake pipe 20 having a cylindrical shape to a plurality of combustion chambers, and the exhaust manifold 3 supplies exhaust gas discharged from the plurality of combustion chambers. It has a plurality of branch parts to guide. In such a configuration, an intake path is formed by the intake pipe 20 and the intake manifold 2, and an exhaust path is formed by the exhaust manifold 3. The intake manifold 2 may be formed with a plurality of branch portions in the same manner as the exhaust manifold 3.

  The throttle valve A has a shaft body 12 penetrating the valve case 11 and a plate-shaped valve body 13 disposed inside the valve case 11 so as to rotate integrally with the shaft body 12. The angle of the valve body 13 is set by 12 rotational operations, and the intake air amount can be adjusted. A flange portion 14 is integrally formed at an end portion of the valve case 11 of the throttle valve A, and the flange portion 14 is connected to a flange portion 22 formed at an end portion of the intake pipe 20 of the intake manifold 2.

  The exhaust manifold 3 is connected to the above-mentioned EGR device B at the base end side of the reduction path 4 for reducing the exhaust gas, and an exhaust gas purification device (not shown) is connected to the exhaust manifold 3 downstream of the exhaust gas discharge path. The exhaust gas that is provided and has not been recirculated to the reduction path 4 is purified by the exhaust gas purification device and then released into the atmosphere.

  The reduction path 4 is composed of a metal pipe whose proximal end is connected to the exhaust manifold 3. Although not shown in the drawing, an EGR cooler that cools the exhaust gas in the middle of the reduction path 4 and an EGR valve that sets the recirculation amount of the exhaust gas may be provided.

[EGR device]
As shown in FIGS. 1 to 4, the metal pipe portion (the downstream portion in the direction in which the exhaust gas is sent) in which the connecting flange body 5 is formed on the tip side of the reduction path 4 is particularly referred to as a duct 6. . The EGR device B as exhaust gas reduction means is composed of a duct 6 and a metal diffuser 30 disposed inside the intake pipe 20 in a state of being connected to the duct 6. In particular, the intake device is configured by the intake pipe 20, the EGR device B, and the mixer body supply system that supplies the diesel engine E with a mixed gas of air and exhaust gas.

  An insertion opening 20A is formed inside the cylindrical structure protruding outward from the wall portion of the intake pipe 20, and a connecting flange 20B is formed at the outer end of the cylindrical structure. The duct 6 is inserted into the intake pipe 20 through the insertion opening 20A, and is held by the intake pipe 20 by bringing the flange body 5 into close contact with the connection flange 20B and connecting with a bolt.

  The diffuser 30 includes a cylindrical member 31 having a cylindrical shape, a conical tip member 32, a plate-like leg portion 33, and a plate-like suppression wall member 34, which are metal materials having high heat resistance. It consists of The diffuser 30 is a flow in which the exhaust gas discharged from the end of the duct 6 directly contacts the inner surface of the intake pipe 20 when the wall of the cylindrical member 31 blocks the flow of the exhaust gas discharged from the duct 6. (This function is common to the diffuser 30 of the second to eighth embodiments described later). The diffuser 30 mixes the exhaust gas received from the duct 6 into the internal space S of the cylindrical member 31 and the air taken in from the intake port F on the distal end side of the cylindrical member 31, and this mixed gas is mixed into the cylindrical member 31. It is configured to be diffused and sent out from the rear end discharge port G into the intake pipe 20. The cylindrical member 31 includes a tip member 32 having a conical shape with a sharpened upstream side at an upstream end in the air flow direction of the intake pipe 20. A pair of legs 33 is provided, and a suppression wall member 34 is provided at the downstream end in the air flow direction.

  The cylindrical member 31 is disposed on the same axis as the axis of the intake pipe 20, and the leading end (the upstream end of the intake pipe 20 in the air flow direction) has a simple circular cross section. A plurality of diffusion pieces 31B are integrally formed at the opening edge on the rear end side opposite to this, and an insertion hole 31C through which the duct 6 is inserted is formed at an intermediate portion. The plurality of diffusion pieces 31 </ b> B are formed in a posture in which resistance is applied to the flow of the mixed gas so as to diffuse the exhaust gas discharged from the rear end side of the cylindrical member 31.

  The tip member 32 is disposed at a position covering the introduction port 31A, is formed in a conical shape with a sharp upstream side, and has a guide portion 32A whose diameter increases toward the downstream side in the air flow direction, and the guide portion 32A. It has a shape in which an outer peripheral portion 32 </ b> B that is continuous with the outer peripheral portion and has a larger diameter than the outer diameter of the tubular member 31 is integrally formed. Cutout portions are formed at a plurality of locations on the outer peripheral portion 32B, and a plurality of connecting pieces 32C are formed by bending a part of the outer peripheral portion. The tip member 32 is connected to the front end portion of the cylindrical member 31 by connecting the end portions of the plurality of connecting pieces 32C to the outer peripheral position of the front end of the cylindrical member 31 by a technique such as spot welding. With such a configuration, an intake port F that guides air from a plurality of notches in the outer peripheral portion 32B of the tip member 32 to the inlet 31A of the cylindrical member 31 is formed.

  By fixing an intermediate portion of a single plate-like member to an intermediate portion of the cylindrical member 31 by a technique such as spot welding, the portions projecting laterally are formed as a pair of leg portions 33. By contacting the outer end position of the leg portion 33 with the inner wall surface of the intake pipe 20, the cylindrical member 31 is located at the center position in the sectional view of the intake pipe 20 (the axis of the intake pipe 20 and the axis of the cylindrical member 31. (Position where the core matches). Note that the diffuser 30 may be configured to include three or more leg portions 33.

  The suppression wall member 34 has a protrusion 34A in which the center position of the disk-shaped member is protruded upstream in the air flow direction, and is a position spaced from the rear end of the diffusion piece 31B to the downstream side in the air flow direction. The outer peripheral portion and the cylindrical member 31 are connected by a connecting member 35. Thereby, the discharge port G is formed by the space between the rear end of the cylindrical member 31 and the suppression wall member 34, and the diffusion piece 31 </ b> B is disposed in the discharge port G. Further, a diffusion portion is configured by the suppression wall member 34 and the plurality of diffusion pieces 31B.

  When the EGR device B is assembled, the diffuser 30 is manufactured by connecting the tubular member 31, the tip member 32, the leg 33, and the suppression wall member 34, and the valve case 11 of the throttle valve A is connected to the intake pipe. Before connecting to the 20 flange portions 22, the diffuser 30 is inserted from the opening of the flange portion 22. Next, the end of the duct 6 inserted through the insertion opening 20A is inserted into the insertion hole 31C of the cylindrical member 31, and the cylindrical member 31 of the diffuser 30 and the duct 6 are connected by a technique such as welding.

  In addition, as a structure which connects the cylindrical member 31 and the duct 6, for example, while forming a recessed part in the outer periphery of the duct 6, the spring material etc. which are elastically fitted to this recessed part are inserted through 31C of the cylindrical member 31. It is also possible to prepare a connected state by elastically fitting a spring material or the like into the recess when the duct 6 is inserted into the insertion hole 31C. In addition to this, a configuration in which the cylindrical member 31 and the duct 6 are connected by screws or the like may be employed. Moreover, as long as the cylindrical member 31 is supported by the leg portion 33, a gap may be provided between the cylindrical member 31 and the duct 6 for assembly.

[Operation and Effect of First Embodiment]
By configuring the EGR device B of the first embodiment in this manner, the exhaust gas sent from the duct 6 to the cylindrical member 31 is blocked by the inner wall of the cylindrical member 31, so that the inner wall surface of the intake pipe 20 is blocked. Without direct contact, the intake pipe 20 is prevented from being damaged by heat, and deposits mainly composed of unburned hydrocarbons or oil mist contained in the exhaust gas adhere to the inner wall surface of the intake pipe 20. (This action / effect is common to the second to eighth embodiments described later). Further, the diffuser 30 is held at the center of the cross section of the intake space of the intake pipe 20 by the leg 33 and the heat of the leg 33 is taken away by the air flowing through the intake pipe 20, so that the intake air caused by the heat transmitted from the diffuser 30 Damage to the tube 20 is suppressed.

  The air sent to the intake pipe 20 is smoothly sent to the side surface of the diffuser 30 at the sharp end of the tip member 32. Further, the air sent to the intake pipe 20 flows into the internal space S of the cylindrical member 31 from the intake port F of the diffuser 30. In addition, since negative pressure is generated between the distal end side of the cylindrical member 31 and the outer peripheral portion 32B at a position covering the air by the air flowing in the outer peripheral portion 32B of the distal end member 32, the inside of the cylindrical member 31 is in this part. The exhaust gas flows out of the air and mixes with the air sent to the intake pipe 20. Due to such a complicated flow, a vortex is generated in the internal space S of the cylindrical member 31, and the exhaust gas and air are mixed. When the mixed gas in which the exhaust gas and the air are mixed is sent out from the discharge port G, the flow is suppressed by the suppression wall member 34 and is sent out while being diffused by the plurality of diffusion pieces 31B. Will mix well with the air sent to.

  In particular, since the diffuser 30 is connected to the tip of the duct 6, it is possible to provide the diffuser 30 having a larger diameter than the duct 6. By providing the large-diameter diffuser 30 in this way, a large capacity can be obtained. After the exhaust gas and air are mixed in advance in the internal space S to create a mixed gas, the mixed gas is sent out in a state of being diffused from the discharge port G having a large cross-sectional area, and is further mixed with the air sent to the intake pipe 20 It is also possible to make it.

[Second Embodiment]
In the second embodiment, the diesel engine E, the intake air amount control system, and the fuel supply system are not different from those of the first embodiment, and the configuration of the EGR device B is different from that of the first embodiment. Configurations common to the first embodiment in the second embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

[EGR device]
As shown in FIG. 5, the diffuser 30 includes a cylindrical member 31 having a cylindrical shape and a conical tip member 32, which are formed of a metal material having high heat resistance. The diffuser 30 receives the exhaust gas sent out from the duct 6 in the internal space S of the cylindrical member 31, mixes it with air taken from the intake port F on the distal end side of the cylindrical member 31, and mixes this mixed gas with the cylindrical member 31. It is configured to diffuse out from the discharge port G at the rear end to the inside of the intake pipe 20 and send it out. In the tubular member 31, a tip member 32 having a conical shape with a sharp upstream side is provided at an upstream end of the intake pipe 20 in the air flow direction.

  The cylindrical member 31 is disposed on the same axis as the axis of the intake pipe 20, and the leading end (the upstream end of the intake pipe 20 in the air flow direction) has a simple circular cross section. A plurality of diffusion pieces 31B are integrally formed at the opening edge on the rear end side opposite to this, and an insertion hole 31C through which the duct 6 is inserted is formed at an intermediate portion. The plurality of diffusion pieces 31 </ b> B are formed in a posture in which resistance is applied to the flow of the mixed gas so as to diffuse the exhaust gas discharged from the rear end side of the cylindrical member 31.

  The tip member 32 is disposed at a position covering the introduction port 31A, and is formed into a conical shape with a sharp upstream side, the diameter of which increases toward the downstream side in the air flow direction, and the outer periphery of the guide portion 32A. A cylindrical portion 32D having an inner diameter that is continuously connected to the cylindrical member 31 is formed, and an intake port F that guides air to the introduction port 31A is formed by cutting a part of the cylindrical portion 32D. . The end member 32 </ b> D is externally fitted to the front end position of the tubular member 31, and the distal end member 32 is coupled to the tubular member 31 by fixing the externally fitted portion by a technique such as spot welding.

  When assembling this EGR device B, the diffuser 30 is inserted from the opening of the flange portion 22 as in the first embodiment, and the end of the duct 6 inserted through the insertion opening 20A is inserted into the cylindrical member 31 of the diffuser 30. An operation of inserting the cylindrical member 31 and the duct 6 by a technique such as welding through the hole 31C is performed.

[Operation / Effect of Second Embodiment]
By configuring the intake device of the second embodiment as described above, the air sent to the intake pipe 20 is smoothly sent to the side surface of the diffuser 30 at the sharp end of the tip member 32. The air sent to the intake pipe 20 flows in from the intake port F of the diffuser 30 and flows into the internal space S of the cylindrical member 31, preventing damage to the intake pipe 20 due to heat, and exhaust gas discharged from the duct 6. After mixing, the air is sent out in a state of being diffused by the plurality of diffusion pieces 31B, and is well mixed with the air sent to the intake pipe 20. In particular, since the intake port F is formed in the outer peripheral portion 32B of the tip member 32, the exhaust gas may be sent out from the inside of the cylindrical member 31, and the flow of the air and the exhaust gas is disturbed to achieve good mixing.

[Third Embodiment]
In the third embodiment, the diesel engine E, the intake air amount control system, and the fuel supply system are not different from those in the first embodiment, and the configuration of the EGR device B is different from that in the first embodiment. In the third embodiment, the same configurations as those of the first embodiment are denoted by the same reference numerals and symbols as those of the first embodiment.

[EGR device]
As shown in FIG. 6, the diffuser 30 includes a cylindrical member 31 having a cylindrical shape and a conical tip member 32, which are formed of a metal material having high heat resistance. The diffuser 30 is configured to receive the exhaust gas sent out from the duct 6 in the internal space S of the cylindrical member 31, diffuse the exhaust gas from the plurality of discharge ports G into the intake pipe 20, and send it out. In the tubular member 31, a tip member 32 having a conical shape with a sharp upstream side is provided at an upstream end of the intake pipe 20 in the air flow direction.

  The cylindrical member 31 has a front end side (an upstream end portion in the air flow direction of the intake pipe 20) disposed on the same axis as the axial center of the intake pipe 20, and a rear end side (the air in the intake pipe 20). The rear end portion is formed in a gently curved shape so that the downstream end portion in the flow direction is disposed in a posture toward the cylinder head 1.

  The rear end side of the cylindrical member 31 reaches the inside of the surge space 21 of the intake manifold 2, and a discharge port G having a simple circular cross section is formed on the rear end side. Two discharge ports G that also function as the intake ports F are formed on the side surface in the vicinity, and an insertion hole 31C through which the duct 6 is inserted is formed in the middle portion.

  Two discharge ports G in the vicinity of the rear end of the cylindrical member 31 are arranged on a single virtual axis (on the axis perpendicular to the paper surface in FIG. 6). The head 1 extends along the direction in which a plurality of intake ports are arranged. As a result, the exhaust gas discharged from the two discharge ports G flows linearly in the direction of the intake port.

  The tip member 32 has a guide portion 32A formed in a conical shape with a sharp upstream side and a diameter that increases toward the downstream side in the air flow direction, and an inner diameter that is connected to the outer peripheral portion of the guide portion 32A and is fitted to the cylindrical member 31. A cylindrical portion 32D is formed. The end portion of the cylindrical portion 32D is externally fitted to the front end position of the cylindrical member 31, and the externally fitted portion is connected by a technique such as spot welding.

  When assembling this EGR device B, the diffuser 30 is inserted from the opening of the flange portion 22 as in the first embodiment, and the end of the duct 6 inserted through the insertion opening 20A is inserted into the cylindrical member 31 of the diffuser 30. An operation of inserting the cylindrical member 31 and the duct 6 by a technique such as welding through the hole 31C is performed.

[Operation and Effect of Third Embodiment]
By configuring the intake device of the third embodiment as described above, the air sent to the intake pipe 20 is smoothly sent to the side surface of the diffuser 30 at the sharp end of the tip member 32. The exhaust gas flows into the internal space S of the diffuser 30 and damage to the intake pipe 20 due to heat is prevented, and from the exhaust port G at the rear end of the cylindrical member 31 and the plurality of exhaust ports G near the rear end. Sent out. In particular, since a plurality of exhaust ports G near the rear end are allowed to enter air (because it also functions as the intake port F), the air that has entered from the exhaust port G is mixed with exhaust gas, It is sent out from a plurality of discharge ports G, and after discharge, it mixes well with the air in the intake pipe 20. Furthermore, the gas mixture sent out from the two outlets G formed in the vicinity of the rear end is supplied to the plurality of intake ports of the cylinder head 1 without being blocked.

[Fourth Embodiment]
In the fourth embodiment, the diesel engine E, the intake air amount control system, and the fuel supply system are not different from those of the first embodiment, and the configuration of the EGR device B is different from that of the first embodiment. Configurations common to the first embodiment in the fourth embodiment are denoted by the same reference numerals and symbols as in the first embodiment.

[EGR device]
As shown in FIG. 7, the diffuser 30 includes a cylindrical member 31 having a cylindrical shape and a conical tip member 32, which are formed of a metal material having high heat resistance. The diffuser 30 is configured to receive the exhaust gas sent out from the tip of the duct 6 into the internal space S of the cylindrical member 31 and diffuse the exhaust gas from the two discharge ports G into the intake pipe 20 and send it out. In the tubular member 31, a tip member 32 having a conical shape with a sharp upstream side is provided at an upstream end of the intake pipe 20 in the air flow direction.

  The cylindrical member 31 has a front end side (an upstream end portion in the air flow direction of the intake pipe 20) disposed on the same axis as the axial center of the intake pipe 20, and a rear end side (the air in the intake pipe 20). The rear end portion is formed in a gently curved shape so that the downstream end portion in the flow direction is disposed in a posture toward the cylinder head 1.

  The rear end side of the cylindrical member 31 reaches the inside of the surge space 21 of the intake manifold 2, and the rear end side opposite to the introduction port 31A is closed. Two discharge ports G that also function as the intake ports F are formed on the side surface in the vicinity of the rear end, and an insertion hole 31C through which the duct 6 is inserted is formed in the middle portion.

  Two discharge ports G in the vicinity of the rear end of the cylindrical member 31 are arranged on a single virtual axis (on the axis in a posture orthogonal to the paper surface in FIG. 7). The head 1 extends along the direction in which a plurality of intake ports are arranged. Thereby, the exhaust gas sent out from the two discharge ports G flows in the direction of the intake port linearly.

  The tip member 32 is formed into a conical shape with a sharp upstream side, and the diameter of the guide portion 32A increases toward the downstream side in the air flow direction. A shaped portion 32D is formed. The end portion of the cylindrical portion 32D is externally fitted to the front end position of the cylindrical member 31, and the externally fitted portion is connected by a technique such as spot welding.

  When assembling this EGR device B, the diffuser 30 is inserted from the opening of the flange portion 22 as in the first embodiment, and the end of the duct 6 inserted through the insertion opening 20A is inserted into the cylindrical member 31 of the diffuser 30. An operation of inserting the cylindrical member 31 and the duct 6 by a technique such as welding through the hole 31C is performed.

[Operation / Effect of Fourth Embodiment]
By configuring the intake device of the fourth embodiment as described above, the air sent to the intake pipe 20 is smoothly sent to the side surface of the diffuser 30 at the sharp end of the tip member 32. Exhaust gas flows into the internal space S of the diffuser 30 and prevents damage to the intake pipe 20 due to heat, and is sent out from the two outlets G near the rear end of the cylindrical member 31. Since the plurality of discharge ports G are allowed to enter air (also functions as the intake port F), the air that has entered from the discharge port G is sent out from the discharge port G while being mixed with the exhaust gas. The mixed gas sent out from the two outlets G is supplied to the plurality of intake ports of the cylinder head 1 without being blocked.

[Fifth Embodiment]
In the fifth embodiment, the diesel engine E, the intake air amount control system, and the fuel supply system are not different from those in the first embodiment, and the configuration of the EGR device B is different from that in the first embodiment. Configurations common to the first embodiment in the fifth embodiment are given the same reference numerals and symbols as in the first embodiment.

[EGR device]
As shown in FIG. 8, the diffuser 30 is configured by a cylindrical member 31 integrally formed with an inner diameter equal to that of the duct 6 by bending the distal end side of the duct 6 at right angles so as to have an elbow shape. The member 31 is made of a metal having high heat resistance. The diffuser 30 receives the exhaust gas sent out from the tip of the duct 6 in the internal space S of the cylindrical member 31 and mixes it with air taken in from a plurality of intake ports F on the tip side of the cylindrical member 31. It is configured to diffuse out from the outlet G at the rear end of the cylindrical member 31 into the intake pipe 20 and send it out.

  The cylindrical member 31 is disposed on the same axis as the axial center of the intake pipe 20, and a plurality of intake ports F are formed on the tip side (the upstream end of the intake pipe 20 in the air flow direction). A circular discharge port G having the same size as the cross section of the cylindrical member 31 is formed on the end side (the end portion on the downstream side in the air flow direction of the intake pipe 20).

  When assembling the EGR device B, an operation of inserting the tubular member 31 together with the duct 6 from the insertion opening 20A is performed.

[Operation / Effect of Fifth Embodiment]
By configuring the intake device of the fifth embodiment as described above, a part of the air sent to the intake pipe 20 is smoothly sent to the side surface of the diffuser 30. The exhaust gas flows into the internal space S of the diffuser 30 and damage to the intake pipe 20 due to heat is prevented, and other part of the air flows into the cylindrical member 31 from the plurality of intake ports F. After mixing with the exhaust gas, it is sent out from the outlet G as a mixed gas and mixed with the air in the intake pipe 20. In this configuration, since air flows into the internal space S of the cylindrical member 31 from the plurality of intake ports F, the air flow is disturbed in the internal space S, and a mixed gas in which air and exhaust gas are mixed well is obtained. Produced.

[Sixth Embodiment]
In the sixth embodiment, the diesel engine E, the intake air amount control system, and the fuel supply system are not different from those of the first embodiment, and the configuration of the EGR device B is different from that of the first embodiment. Configurations common to the first embodiment in the sixth embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

[EGR device]
As shown in FIG. 9, the diffuser 30 includes a cylindrical member 31 formed integrally with the duct 6 on the leading end side of the duct 6, and the cylindrical member 31 is formed of a metal having high heat resistance. . The diffuser 30 is configured to diffuse exhaust gas from the exhaust port G at the rear end of the cylindrical member 31 to the inside of the intake pipe 20 (not shown in the drawing). The discharge port G is formed in a rectangle whose one side is longer than the other side.

  When assembling the EGR device B, an operation of inserting the tubular member 31 together with the duct 6 from the insertion opening 20A is performed.

[Operation / Effect of Sixth Embodiment]
By configuring the intake device of the sixth embodiment as described above, the air sent to the intake pipe 20 is sent to the side surface of the diffuser 30. The exhaust gas flows into the internal space S of the diffuser 30 and damage to the intake pipe 20 due to heat is prevented, and the exhaust gas is sent out from the exhaust port G and mixed with the air in the intake pipe 20. In particular, since the cylindrical member 31 is formed in a rectangular pipe shape having a rectangular cross-sectional shape, there are different regions in the distance between the outer surface of the cylindrical member 31 and the inner surface of the intake pipe 20, and each region has a different region. Since there is a difference in the flow velocity of the flowing air, the air flow is disturbed, and the exhaust gas sent out from the discharge port G is well mixed with the air in a stirred form.

[Seventh Embodiment]
In the seventh embodiment, the diesel engine E, the intake air amount control system, and the fuel supply system are not different from those of the first embodiment, and the configuration of the EGR device B is different from that of the first embodiment. In the seventh embodiment, the same configurations as those in the first embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

[EGR device]
As shown in FIG. 10, the diffuser 30 is configured by a cylindrical member 31 having a cylindrical shape, and the cylindrical member 31 is configured by a metal material having high heat resistance. The diffuser 30 receives the exhaust gas sent out from the duct 6 in the internal space S of the cylindrical member 31, mixes it with air taken from the intake port F on the distal end side of the cylindrical member 31, and mixes this mixed gas with the cylindrical member 31. It is configured to diffuse out from the discharge port G at the rear end to the inside of the intake pipe 20 and send it out.

  The cylindrical member 31 is disposed on the same axis as the axial center of the intake pipe 20, and the tip end (the upstream end of the intake pipe 20 in the air flow direction) has a circular cross section with a diameter D1. F is formed, a discharge port G having a circular cross section with a diameter D2 smaller than the diameter D1 is formed on the rear end side opposite to this, and an insertion hole 31C through which the duct 6 is inserted is formed in the middle portion. Yes. From such a configuration, the duct 6 is connected to the rear end side of the tubular member 31 in a communicating state. The cross section of the cylindrical member 31 is not limited to a circle, and may be an ellipse or a polygon. Further, the cylindrical member 31 may be configured such that the cross-sectional area of the intake port F on the front end side is smaller than the cross-sectional area of the discharge port G on the rear end.

  When assembling this EGR device B, the diffuser 30 is inserted from the opening of the flange portion 22 as in the first embodiment, and the end of the duct 6 inserted through the insertion opening 20A is inserted into the cylindrical member 31 of the diffuser 30. An operation of inserting the cylindrical member 31 and the duct 6 by a technique such as welding through the hole 31C is performed.

[Operation / Effect of Seventh Embodiment]
By configuring the intake device of the seventh embodiment in this way, a part of the air sent to the intake pipe 20 flows to the side surface of the diffuser 30. The exhaust gas flows into the internal space S of the diffuser 30 and damage to the intake pipe 20 due to heat is prevented, and a part of the air flows from the intake port F and mixes with the exhaust gas inside the cylindrical member 31. After that, it is sent out from the outlet G as a mixed gas and mixed with the air in the intake pipe 20.

  In particular, since the flow rate of air when the air flowing in from the intake port F of the diffuser 30 flows out of the discharge port G is lower than the flow rate of air flowing outside the diffuser 30, the exhaust gas and air are mixed inside the diffuser 30. When the mixed gas is sent out from the discharge port G, mixing is promoted by generating a vortex from the turbulence in the air flow due to the respective speed differences.

[Eighth Embodiment]
In the eighth embodiment, the diesel engine E, the intake air amount control system, and the fuel supply system are not different from those of the first embodiment, and the configuration of the EGR device B is different from that of the first embodiment. Configurations common to the first embodiment in the eighth embodiment are denoted by the same reference numerals and symbols as in the first embodiment.

[EGR device]
As shown in FIG. 11, the diffuser 30 includes a cylindrical member 31 having a cylindrical shape and a conical tip member 32, which are formed of a metal material having high heat resistance. The diffuser 30 is configured to receive the exhaust gas sent out from the duct 6 in the internal space S of the cylindrical member 31, diffuse the exhaust gas from the discharge port G on the distal end side of the cylindrical member 31 to the inside of the intake pipe 20, and send it out. Yes. In the tubular member 31, a tip member 32 having a conical shape with a sharp upstream side is provided at an upstream end of the intake pipe 20 in the air flow direction.

  The cylindrical member 31 is disposed on the same axis as the axial center of the intake pipe 20, and a plurality of discharge ports G are formed on the outer periphery on the tip side (the upstream end in the air flow direction of the intake pipe 20). In addition, an insertion hole 31C through which the duct 6 is inserted is formed in the intermediate portion. The tip member 32 is formed into a conical shape with a sharp upstream side, and has a guide portion 32A whose diameter increases toward the downstream side in the air flow direction, and an outer peripheral portion of the guide portion 32A, and is fitted around the outer periphery of the cylindrical member 31. A connecting portion 32E and a cylindrical portion 32D that is connected to the connecting portion 32E and is disposed at a position that covers the discharge port G are formed. And the front-end | tip member 32 is connected with the cylindrical member 31 by externally fitting the connection part 32E in the front-end position of the cylindrical member 31, and fixing this external fitting part by techniques, such as spot welding.

  When assembling this EGR device B, the diffuser 30 is inserted from the opening of the flange portion 22 as in the first embodiment, and the end of the duct 6 inserted through the insertion opening 20A is inserted into the cylindrical member 31 of the diffuser 30. An operation of inserting the cylindrical member 31 and the duct 6 by a technique such as welding through the hole 31C is performed.

[Operation / Effect of Eighth Embodiment]
By configuring the intake device of the eighth embodiment as described above, the air sent to the intake pipe 20 is smoothly sent to the side surface of the diffuser 30 at the sharp end of the tip member 32. The exhaust gas flows into the internal space S of the diffuser 30, and damage to the intake pipe 20 due to heat is prevented, and the exhaust gas is sent out from the exhaust port G and mixed with the air in the intake pipe 20. In particular, since the plurality of discharge ports G are arranged in the space covered by the cylindrical portion 32D of the tip member 32 on the front end side of the cylindrical member 31, a part of the air flowing through the intake pipe 20 is the cylindrical portion 32D. The vortex flow is created by flowing into the inside of the gas and mixed well with the exhaust gas sent from the discharge port G. Further, in this configuration, the distance from the discharge port G to the intake port of the cylinder head can be made longer than that in which the discharge port G is formed at the rear end of the cylindrical member 31, so that the exhaust gas passes through a long distance. To achieve good mixing with air.

[Another embodiment]
The present invention may be configured as follows in addition to the embodiment described above.

(A) The shape of the intake port F formed in the diffuser 30 is, for example, a cross-shaped opening or a star shape, so that it acts on the air at the central portion and the outer end portion of the intake port F. Different resistance values are used to actively disturb the air flow. Thereby, the air and the exhaust gas are mixed well in the internal space S of the cylindrical member 31.

(B) The shape of the discharge port G formed in the diffuser 30 is, for example, a cross-shaped opening or a star shape, so that a mixed gas or The resistance value that acts when exhaust gas is discharged is varied to actively disturb the flow. Thereby, the flow of the mixed gas or exhaust gas sent out from the internal space S of the cylindrical member 31 is disturbed to create a vortex or the like, and can be mixed well with the air sent to the intake pipe 20.

(C) A part of the configuration of the first to eighth embodiments is appropriately combined. Specifically, in the third embodiment and the fifth embodiment, the diffusion piece 31B of the first and second embodiments is formed on the outlet G at the rear end of the cylindrical member 31, The structure which attaches the suppression wall member 34 is employ | adopted. Similarly, the structure which attaches the leg part 33 of 1st Embodiment to the outer surface of the cylindrical member 31 of other embodiment is employ | adopted. By adding the configuration in this way, it is possible to achieve a favorable aspect of the configuration added in each embodiment.

  The present invention can be used for general internal combustion engines such as gasoline engines in addition to diesel engines.

2 Intake Manifold 6 Duct 20 Intake Pipe 20A Insertion Opening 30 Diffuser 31A Diffusion Part (Diffusion Piece)
34 Diffusion part (suppression wall member)
33 Leg A Throttle valve B Exhaust gas reduction means (EGR device)
E Internal combustion engine (diesel engine)
G outlet

Claims (5)

As an exhaust gas reduction means for reducing a part of the exhaust gas of the internal combustion engine inside the resin intake pipe that sends air to the combustion chamber of the internal combustion engine, a duct for sending the exhaust gas to the inside of the intake pipe, And a diffuser that sends the exhaust gas to the inside of the intake pipe,
The duct is inserted into the intake pipe from an insertion opening formed in the wall surface of the intake pipe,
In the diffuser, an internal space having a wall portion that prevents a flow of exhaust gas sent from the end of the duct from directly contacting the inner wall of the intake pipe is formed, and the exhaust gas received in the internal space is A discharge port is formed that diffuses and feeds inside the intake pipe .
An intake device for an internal combustion engine, wherein the diffuser is formed in a shape in which an upstream end portion in an air flow direction in the intake pipe is sharpened .   The intake device for an internal combustion engine according to claim 1, wherein the exhaust port of the diffuser includes a diffusion unit that diffuses the exhaust gas by disturbing a flow of the exhaust gas sent out from the internal space.   3. The internal combustion engine according to claim 1, wherein a plurality of legs that are in contact with the inner surface of the intake pipe are provided on the outer surface of the diffuser in order to hold the diffuser at a central position in the cross section of the intake space of the intake pipe. Inhalation device.   In the diffuser, the size of the cross-sectional area of the upstream inlet in the air flow direction in the intake pipe is different from the size of the cross-sectional area of the discharge port in the downstream of the air flow direction in the intake pipe. The intake device for an internal combustion engine according to claim 1, wherein the duct is connected to a portion on the outlet side in a communicating state. The intake pipe constitutes an intake manifold connected to the internal combustion engine on the downstream side in the air flow direction, and a throttle valve for controlling the air amount is connected on the upstream side in the air flow direction,
The diffuser is after said throttle valve is inserted from an opening which connects the interior of the intake pipe, in claim 1 any one of 4, which is connected to the distal end of the duct to be inserted from the insertion opening An intake device for an internal combustion engine as described.

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