JP2007224813A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for improving the mixed state of an EGR mixed gas more inexpensively and easily in an EGR device of an internal combustion engine having a reflux passage between a suction manifold and an exhaust manifold for refluxing a part of the exhaust gas to the suction side. <P>SOLUTION: In the internal combustion engine, the refluxing passage (EGR pipe 27) is formed between the suction manifold 6 and the exhaust manifold 7 to reflux the part of the exhaust gas. Blade bodies 41b are installed in an EGR gas inlet port 6b of the suction manifold 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technology of an EGR (Exhaust Gas Recirculation) device for an internal combustion engine having a circulation passage between an intake manifold and an exhaust manifold in order to circulate a part of exhaust gas to the intake side. More specifically, the present invention relates to a technique for effectively mixing EGR gas and intake air in an intake manifold.

2. Description of the Related Art Conventionally, in an internal combustion engine (diesel engine) mounted on a work machine, a moving vehicle, or the like, an EGR device has been known in order to reduce nitrogen oxides generated during combustion as a countermeasure against environmental pollution. In this EGR device, a part of exhaust gas exhausted from the exhaust manifold (EGR gas) is recirculated to the intake manifold and mixed with intake air to reduce the combustion temperature in the combustion chamber, thereby reducing nitrogen oxides. It aims to make it easier. Here, in order to further effectively reduce nitrogen oxides, various improvements have been known in the art in order to improve the mixing state of the EGR mixed gas sent to each combustion chamber.
For example, in “Patent Document 1”, in order to improve the mixing state of the EGR mixed gas, the cross-sectional area of the intake pipe communicating with the intake manifold is increased, and the EGR gas is taken in and out of the passage along with the intake air. Two mixing blades are provided inside and outside and front and rear so as to turn in the outer and inner directions and reversely turn in one or the other direction from the flow direction of the intake air.
Japanese Utility Model Publication No. 6-29491

In the above known technique, the mixing state of the EGR mixed gas can be made more uniform by the flow of the fluid itself without providing any other special mixing device. However, the production of the mixing blade in the above-mentioned known technique requires a high level of technical skill, and the number of assembling steps is increased, which cannot be easily handled.
In view of these circumstances, an object of the present invention is to provide a technique for improving the mixed state of an EGR mixed gas that can be easily implemented at a lower cost.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  In other words, in the internal combustion engine in which a circulation passage is formed between the intake manifold and the exhaust manifold so that a part of the exhaust gas is circulated to the intake side, the blade body is provided at the EGR gas inlet of the intake manifold. Is provided.

  According to a second aspect of the present invention, the blade body is formed integrally with a gasket interposed between the intake manifold and the circulation passage.

  According to a third aspect of the present invention, the blade body has a configuration in which a plurality of fins are disposed with an inclination about the axis of the circulation passage and the passing EGR gas becomes a swirling flow.

  According to a fourth aspect of the present invention, in the internal combustion engine in which a circulation passage is formed between the intake manifold and the exhaust manifold to circulate a part of the exhaust gas to the intake side, the EGR gas inflow port is an air intake port of the intake manifold. A wall portion provided in the vicinity and projecting toward the intake air flow side is provided on the downstream side of the EGR gas inlet.

  According to a fifth aspect of the present invention, in the internal combustion engine in which a recirculation passage is formed between the intake manifold and the exhaust manifold, and a part of the exhaust gas is recirculated to the intake side, the end of the recirculation passage is configured in a pipe shape. The pipe part at the end of the passage is inserted into the intake manifold in parallel with the crankshaft, and an outlet hole is drilled in the pipe part according to the position of the intake port, and the angle can be changed between the pipe part and the intake port. A simple valve element is arranged.

  According to a sixth aspect of the present invention, in the internal combustion engine in which a recirculation passage is formed between the intake manifold and the exhaust manifold and a part of the exhaust gas is recirculated to the intake side, the end of the recirculation passage is configured in a pipe shape, The pipe part at the end of the passage is inserted into the intake manifold in parallel with the crankshaft, and an outlet hole is drilled in the pipe part according to the position of the intake port, and a valve body is provided along the outlet direction of the outlet hole. The pipe portion is configured so that the angle can be changed.

  According to a seventh aspect of the present invention, one end of the pipe portion is connected to an actuator so that the angle can be changed according to the operating conditions of the internal combustion engine.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, since the intake manifold is connected to the outlet side front end portion of the circulation passage via the blade body, the circulation gas (hereinafter referred to as “EGR gas”) flowing into the intake manifold is always the blade. The direction of flow in contact with the body is changed and diffused, and the intake air and the EGR gas are mixed to achieve uniformity. Further, since the blade body is disposed at the outlet side tip of the circulation passage, there is almost no obstacle to the flow of the intake air, and the balance of the supplied intake air amount is not lost.

  In claim 2, since the blade body is integrated with the gasket, a bracket or the like for mounting the blade body is unnecessary, the number of parts is not increased, and the blade body is manufactured at a relatively low cost by stamping with a press machine. be able to.

  According to a third aspect of the present invention, since the blade body is composed of a plurality of inclined fins, the EGR gas that has flowed into the intake manifold comes into contact with the blade body to generate a swirling flow. Mixing is further promoted.

  According to a fourth aspect of the present invention, a wall member projecting toward the intake air flow side is provided on the downstream side of the EGR gas inlet, whereby a vortex is generated on the downstream side of the wall portion, and mixing of the EGR gas and the intake air is performed. Can be promoted. Moreover, since the wall material can be configured as a simple protrusion, it can be realized at low cost.

  According to the fifth aspect of the present invention, the valve body capable of changing the angle is arranged between the end of the pipe-shaped circulation passage inserted into the intake manifold and the intake port, whereby the flow direction of the EGR gas is changed by the valve body. Thus, a turbulent flow is generated in the intake port due to a difference in partial flow velocity, and mixing of the EGR gas and the intake air is further promoted, and the uniformity of the mixed gas is improved. Further, by adjusting the angle of the valve body, it is possible to perform optimal swirl control in accordance with the characteristics of the internal combustion engine.

  According to the sixth aspect of the present invention, it is possible to freely change the discharge direction of the EGR gas by changing the angle of the valve body and the pipe portion, and the EGR gas is supplied to each supply port according to the characteristics of the internal combustion engine. Can be supplied. In addition, the flow direction of the intake air is freely changed by the valve body, and a turbulent flow is generated in the intake port due to a difference in partial flow velocity, so that the mixing of the EGR gas and the intake air is further promoted, and the mixed gas becomes uniform. Is improved.

  According to the seventh aspect of the present invention, the pipe portion is rotated by an actuator in accordance with the operating characteristics (output, rotational speed, etc.) of the internal combustion engine so that the angle of the valve body can be changed, so that mixing supplied to the intake port The gas can be made to accurately correspond to the operating situation, and the optimum mixing ratio of the EGR gas and the intake air can be realized.

Next, embodiments of the invention will be described.
1 is a front perspective view showing an overall configuration of an engine according to an embodiment of the present invention, FIG. 2 is a rear perspective view, and FIG. 3 is a front view showing an internal structure of the engine.
FIG. 4 is a view showing a circulation passage and an intake manifold in which a blade body according to the present invention is provided in a gap portion. In FIG. 4, (a) is a cross-sectional view modeling the entire configuration, and (B) is FIG.
5 is an overall cross-sectional view (a) modeling the structure of a conventional intake manifold and a cross-sectional view (b) near the intake inlet, and FIG. 6 is a wall suspended from the EGR gas inlet according to the present invention to the intake flow side. FIG. 6 is a cross-sectional view modeling the vicinity of the intake inlet of the intake manifold in which mixing of the EGR gas is promoted by a section.
FIG. 7 is a view showing a pipe-shaped circulation passage and an intake manifold provided with a swingable valve body at the intake port inlet according to the present invention, and (a) in FIG. (B) is a detailed view seen from the cross-section Y.
FIG. 8 is a view showing a pipe-shaped recirculation passage and an intake manifold integrated with a swingable valve body according to the present invention, and (a) in this figure is a cross-section modeling the entire structure. The figure (b) is a detailed view seen from the cross section Z.

[Entire engine configuration]
First, as an example of an internal combustion engine to which the present invention is applied, an overall configuration of a diesel engine (hereinafter referred to as “engine 1”) mounted on a work machine or the like will be described with reference to FIGS. 1 to 3. (The direction of arrow A shown in FIGS. 1 and 2 indicates the front-rear direction.)
In addition, the engine 1 applied to this invention has shown the diesel engine provided with the EGR (Exhaust Gas Recirculation) apparatus.
Here, the EGR device is a part of the exhaust gas discharged from the exhaust manifold 7 (reflux gas; hereinafter referred to as “EGR gas”) in order to reduce the amount of nitrogen oxides contained in the exhaust gas. This is a device that recirculates to the intake manifold 6 and mixes it with intake air, thereby lowering the combustion temperature in the cylinder block and reducing the generation amount of nitrogen oxides.

  A cylinder head 3 is attached to an upper portion of a cylinder block 2 provided in the engine 1, and an upper surface of the cylinder head 3 is covered with a bonnet 4. An oil pan 5 is attached to the lower part of the cylinder block 2, and engine oil (lubricating oil) is stored in the oil pan 5. The lubricating oil is sucked by the lubricating oil pump 22 and supplied to each lubricating portion in the engine 1 through the lubricating oil filter 20.

An intake manifold 6 is provided on one side of the cylinder head 3, and an exhaust manifold 7 is provided on the opposite side.
An intake pipe 28 (see FIGS. 4 to 8) is connected to one end of the intake manifold 6, and an air cleaner (not shown) is disposed at the tip of the intake manifold 6 to temporarily filter the intake air from the atmosphere. After removing dust, etc., it is taken into the cylinder block 2. Further, an EGR valve 26 (see FIG. 4) is disposed in the vicinity of the connection portion of the intake pipe 28, and the exhaust manifold 7 and the circulation passage (hereinafter referred to as “EGR pipe 27”) are provided via the EGR valve 26. 4 and FIGS. 7 to 8). The EGR valve 26 finely adjusts the opening amount of the discharge valve by electrical control. That is, according to conditions such as the rotational speed and temperature of the engine 1, the EGR gas and the intake air have an optimum mixing ratio, can be started easily, and the emission amount of nitrogen oxides can be reduced. 2 is an apparatus for adjusting the discharge amount of EGR gas to the intake manifold 6.
An exhaust pipe (not shown) is connected to one end side of the exhaust manifold 7, and a muffler is disposed at the tip of the exhaust pipe. As a result, the pressure fluctuation of the explosive sound energy discharged together with the exhaust is canceled out and absorbed, and the sound is calmed down.

  A fuel injection pump 8 for sending fuel to be injected into a combustion chamber formed in the cylinder block 2 is attached to one side of the cylinder block 2 below the intake manifold 6. The fuel injection pump 8 is provided with a governor for adjusting the fuel injection amount, and the adjustment in the governor is performed by turning the governor lever 9. A fuel feed pump 10 that supplies fuel into the engine 1 is provided below the fuel injection pump 8. The fuel in the fuel tank (not shown) is sucked and sent out by the fuel feed pump 10 and introduced into the fuel injection pump 8 through the fuel filter 19 provided in the fuel supply path of the engine 1.

A crankshaft 23 is rotatably supported in the cylinder block 2, and gears for transmitting the power of the crankshaft 23 to the fuel injection pump 8 and the like are housed on the front surface of the cylinder block 2. A gear case 11 is attached and is covered with a gear case cover 12. A cooling fan 25 is attached to the front side of the gear case 11, and the cooling fan 25 has a V pulley 14 and a V belt that are driven by the crank shaft 23, and the power of the crank shaft 23 is provided on the front surface of the gear case 11. 15 is transmitted through 15 and rotates. The power of the crankshaft 23 is also transmitted to the alternator 30 provided on the front side of the cylinder block 2 through the V pulley 14 and the V belt 15. A cooling water pump 21 for lubricating engine cooling water is provided on the front surface of the cylinder block 2 coaxially with the cooling fan 25.
On the other hand, a flywheel housing 18 that covers a flywheel 31 attached to the rear end of the crankshaft 23 is fixed to the rear surface of the cylinder block 2.

  As described above, the fuel injection pump 8 is driven by the rotation of the crankshaft 23 being transmitted. The rotation of the crankshaft 23 is an idle mechanism that serves as an idle mechanism housed in the gear case 11 as shown in FIG. It is transmitted to the drive shaft (hereinafter simply referred to as “pump drive shaft”) 34 of the fuel injection pump 8 via the gear 35. Specifically, a crank gear 36 is fixed to the front end portion of the crankshaft 23, and the crank gear 36 meshes with the idle gear 35. The idle gear 35 is supported on an idle shaft 32 supported by the gear case 11. The idle gear 35 meshes with a fuel injection pump drive gear 33 fixed to the pump drive shaft 34, and transmits the power of the crankshaft 23 to the fuel injection pump 8. In this embodiment, power transmission is transmitted by a gear mechanism, but it can also be transmitted by a chain, a belt, or the like. Therefore, when driven by a chain, the idle gear is replaced by an idle sprocket, and when transmitted by a belt, the idle gear is replaced by an idle pulley.

  Further, as described above, the lubricating oil sucked by the lubricating oil pump 22 is specifically supplied as follows. That is, as shown in FIG. 3, a lubricating oil pump driving gear 22 a is fixed to the driving shaft of the lubricating oil pump 22, and the lubricating oil pump driving gear 22 a meshes with the crank gear 36. The power of the crankshaft 23 that is driven when the engine 1 is started is transmitted to the lubricating oil pump 22 via the crank gear 36 and the lubricating oil pump driving gear 22a, and the lubricating oil pump 22 is driven. As a result, the lubricating oil stored in the oil pan 5 is sucked by the lubricating oil pump 22 through the strainer 29 through the lubricating oil supply pipe 37. The lubricating oil sucked in by the lubricating oil pump 22 is sent to a main gallery 38 formed in the cylinder block 2 through a lubricating oil path (not shown) and guided to each lubricating location in the engine 1.

[Intake Manifold Example 1]
Next, as a first embodiment of the present invention, the structure of the connection portion between the intake manifold 6 and the EGR pipe 27 will be described. FIG. 4 shows a model of the structure of the first embodiment. FIG. 4A is an overall sectional view of the gasket, and FIG. 4B is a view of the gasket viewed from the X direction shown in FIG. This will be described below with reference to this figure. Note that arrows B and C shown in the figure indicate the flow directions of EGR gas and intake air, respectively.

The EGR pipe 27 is connected to the intake manifold 6 via the EGR valve 26 with a gasket 41 disposed therebetween.
In the intake manifold 6, the same number of intake ports 6 a as the number of cylinders are perforated on the connection surface with the cylinder head 3, and an opening is provided on one end side for connection to the intake pipe 28. An EGR gas inlet 6b is provided in the vicinity of the opening and is connected to the EGR pipe 27 as described above. Here, since the inlet 6b is provided at a right angle to the flow direction of the intake air, the flow direction of the EGR gas flowing into the intake manifold 6 is forcibly changed immediately after that, The mixing action of is promoted.

  The gasket 41 is formed of a thin plate member made of a non-metallic sealing material, and a fin-like blade body 41b is integrally formed by providing a notch 41a at a central portion thereof and inclining and bending the plurality of fins. Is arranged with an inclination about the axis of the circulation passage. In this embodiment, two fan-shaped cuts 41a are provided radially. The plurality of fan-shaped cuts 41a are held in a part thereof without being cut off from the periphery, and are bent using the part to form a fin shape as a whole between the fin and the main body. An intake hole is formed in the front.

  By adopting such a configuration, when the EGR gas that has flowed in through the EGR pipe 27 passes through the notch 41a of the gasket 41, the flow direction is regulated by the blade body 41b without being subjected to excessive resistance. It flows into the intake manifold 6 as a flow. Then, it intersects with the intake air sucked from the intake pipe 28 in the direction perpendicular to it, and can further promote the mixing action.

  The fan-shaped cuts 41a provided in the gasket 41 are not limited to being provided as two as in the present embodiment, and one fan-shaped cut 41a is possible as long as it is possible to generate a swirling flow without difficulty in the passing EGR gas. Alternatively, it may be a plurality of three or more. Furthermore, the shape of the cut 41a is not a fan shape, and may be formed in, for example, a triangular shape or another polygonal shape.

[Intake manifold embodiment 2]
Next, the structure of the intake manifold 6 will be described as a second embodiment of the present invention.
As described above, the intake manifold 6 is provided with an intake air (atmosphere) inlet 13c and an EGR gas inlet 6b (FIG. 5) on one end side. First, a conventional intake manifold 13 (hereinafter referred to as “old intake manifold 13”) will be described with reference to FIG. (The direction of the arrow A shown in FIG. 5 indicates the front-rear direction.) FIG. 5 is a cross-sectional view of the old intake manifold 13, and (a) in FIG. ) Is a side view of (A) viewed from the direction of arrow a. Note that arrows B, C, and D shown in the figure indicate the flow directions of EGR gas, intake air, and mixed gas, respectively.

  The old intake manifold 13 has a substantially rectangular shape extending in the front-rear direction, and communicates with each intake port of the cylinder head 3. In FIG. 5A, the side wall 13b of the side surface portion is smoothly inclined toward the cylinder head 3 from the vicinity of the inlet of the intake air toward the front. The rear part is open as an inlet for intake air, and the front part is closed by a wall. Further, at the same time when viewed from the side, the inlet portion of the intake air is provided with an EGR gas inlet 13a on the upper surface, so that the intake air and EGR gas sucked into the old intake manifold 13 are orthogonal to each other in the vicinity of the inlet. Then, the mixed gas mixed after that was sent to each combustion chamber in the cylinder block 2 along the side wall 13b inclined as described above. However, in this structure, even if both gases are sucked at right angles to each other due to the pressure drop in the old intake manifold 13, the flow is immediately aligned in the same direction, that is, in the forward direction. The EGR amount of the mixed gas sent into the combustion chamber was likely to vary.

In the second embodiment of the present invention, an improvement is added to the structure of the opened rear portion, that is, the upstream side of the intake air, in the old intake manifold 13. In the vicinity of the rear opening of the intake manifold 6, a wall (projection) 6 d is provided at a right angle to the flow direction of the intake air immediately downstream of the EGR gas inlet 13 a so that the intake air and the EGR gas are separated from each other. Immediately after mixing, a turbulent flow is forcibly generated to promote the mixing action.
FIG. 6 is a side view showing a cross section of the intake manifold 6 according to the second embodiment of the present invention, in which a rear opening portion is modeled, and will be described below with reference to this drawing. (The direction of arrow A shown in FIG. 6 indicates the front-rear direction.) In addition, arrows B, C, and D shown in the figure indicate the flow directions of EGR gas, intake air, and mixed gas, respectively.

In the rear upper part of the intake manifold 6, an EGR gas inlet 6 b is penetrated through the upper surface member 6 e, and a wall portion 6 d for preventing the flow of intake air from the lower surface of the upper surface member 6 e is provided in front or downstream thereof. ing.
The side wall 6d is hanged perpendicularly to the flow direction of the intake air downward as viewed from the side, and further, an opening 6f having a smaller opening area than the rear opening is formed in the lower part. .

  By having such a structure, the intake air that has flowed in comes into contact with the wall 6d and generates a vortex (turbulent flow) that wraps downward. On the other hand, after the EGR gas is supplied from the inlet 6b, it intersects with the flow direction of the intake air at right angles, and the flow is aligned in the flow direction of the intake air because of the pressure drop in the manifold 6 as described above. However, the turbulent flow of the intake air crosses uniformly as a mixed gas. Furthermore, the mixed gas that has passed through the wall 6d is once throttled by the opening 6f and then released to generate Karman vortices from the orifice effect, thereby further promoting the mixing action of the mixed gas. As a result, the distribution of the EGR gas amount of the mixed gas supplied to each cylinder is made uniform, and the generation of nitrogen oxides in the EGR device can be further reduced.

  Note that the structure of the wall portion 6d is not limited to an integral structure with the upper surface member 6e. For example, the wall portion 6d is assembled as a separate structure to the upper surface member 6e with a fastening part such as a bolt. It may be possible to reduce the manufacturing cost by avoiding the processing difficulty in the case of the structure.

[Intake manifold embodiment 3]
Next, as a third embodiment of the present invention, a structure of a connection portion between the intake manifold 6 and the EGR pipe 27 will be described. FIG. 7 shows a cross-sectional view modeling the structure. In FIG. 7, (a) is shown in a plan view, and (b) is shown in a side view seen from the direction of the arrow Y with respect to (a). This will be described below with reference to this figure. Note that arrows B and C shown in the figure indicate the flow directions of EGR gas and intake air, respectively.

  In this embodiment, a pipe portion 27c extending from the tip of the EGR pipe 27 is inserted into the intake manifold 6, and the same number of valve bodies 42 as the intake ports 6a are provided, and are arranged in parallel with the pipe portion 27c. The present invention relates to an EGR gas supply unit composed of a swirl control mechanism (rotation angle changing mechanism) 43.

  The EGR pipe 27 is directly opposed to the intake ports 6a, 6a, etc. with the pipe portion 27c at the tip thereof directly inserted from one side of the intake manifold 6 via the EGR valve 26 (see FIG. 4). It is penetrated by the side part to do. Here, the direction in which the pipe portion 27c is inserted is parallel to a crankshaft (not shown) provided in the cylinder block 2, and the pipe portion 27c is arranged in accordance with the arrangement of the intake ports 6a to each cylinder. On one side surface, a plurality of outflow holes 27a are perforated toward the intake port 6a. Further, the tip portion of the pipe portion 27c is closed with a seal tape, a plug or the like (not shown) in order to prevent the release of EGR gas to the outside of the intake manifold 6.

  The swirl control mechanism 43 includes a plurality of valve bodies 42 that regulate the flow direction of the mixed gas, a turning shaft 44 into which the plurality of valve bodies 42 are inserted, and a drive motor 45 that serves as an actuator that moves the turning shaft 44. It is comprised by.

The valve body 42 has a substantially rectangular shape in a plan view, and has a streamline shape smoothly narrowed from the insertion portion of the pivot shaft 44 toward the opposite side in a side view, and the distal end on the opposite side A portion is directed to the intake port 6a, and a part of the tip is disposed so as to overlap the intake port 6a. The valve body 42 is arranged in accordance with the position of the outflow hole 27a drilled in the pipe portion 27c in plan view, and the outflow hole 27a, the valve body 42 and the intake port 6a are in plan view and side view. It is the structure arranged in parallel on a straight line.
The shape of the valve body 42 is not limited to the shape as in the present embodiment, and may be, for example, an elliptical shape or a polygonal shape, but it is desirable to have an appropriate shape by analyzing the airflow of the mixed gas. .

The turning shaft 44 is arranged in parallel with the pipe portion 27c, and is inserted from one side surface of the intake manifold 6 in the same manner as the pipe portion 27c, and passes through the side surface portion facing it as it is. The both insertion parts are pivotally supported via ball bearings 46 and the like, and a gear 47 is fixed to one end.
A key groove 48 is provided in the central portion of the turning shaft 44 in accordance with the arrangement of the valve body 42, and the valve body 42 is fixed to the turning shaft 44 through a key 49. Therefore, the valve element 42 is rotated following the rotation of the swing axis.
Thus, the turning shaft 44 is disposed between the pipe portion 27c and the intake port 6a, and the valve body 42 protrudes and is fixed on the turning shaft 44 so as to face the intake port 6a.
One end of the swivel shaft 44 extends somewhat and a gear 47 is fixed. The gear 47 meshes with a gear 50 fixed to the drive motor 45, and when the driving force of the drive motor 45 is transmitted, the turning shaft 44 is turned and the orientation of the valve body 42 is controlled. Is done. As a control method of the valve element 42, the controller 1 that senses the engine speed, temperature, and other conditions with a detector such as an encoder or a thermometer and outputs an electrical signal to the controller. The rotation speed and rotation angle are determined by a preset program and output to the drive motor 45 as a command signal. Upon receiving the command signal, the drive motor 45 is driven as specified, and the direction of the valve body 42 is controlled. The valve element 42 may be configured to change the angle in accordance with the operating conditions of the internal combustion engine, or may be configured to reciprocally swing up and down by a set angle, or may be configured to change the swing cycle. It doesn't matter.

  By adopting such a configuration, the EGR gas introduced directly to the vicinity of each intake port 6a using the pipe portion 27c comes into contact with the valve body 42 immediately after being discharged from the outflow hole 27a, and the flow direction is made up and down. It is divided to generate a swirling flow, and the mixing action with the intake air is promoted. Thereafter, the mixed gas of the EGR gas and the intake air is guided to the intake port 6a along the outer shape of the valve body 42. The vicinity of the inlet of the intake port 6a is divided into upper and lower parts depending on the orientation of the valve body 42, and Since the opening areas are different, swirl (Karman vortex) is generated by the orifice effect when passing through the vicinity of the inlet, and the mixed gas is further promoted to mix.

  As for the fixing method of the EGR pipe 27 and the intake manifold 6, in this embodiment, a flange part 27b is provided on the EGR pipe 27 side and a fastening part such as a bolt is used. For example, the EGR pipe 27 may be fixed to the intake manifold 6 directly by welding. In the present embodiment, the drive method of the swirl control mechanism 43 is a gear-coupled drive motor system, but the present invention is not limited to this. For example, the gear coupling portion may be constituted by a pulley and a V-belt. More specifically, a hydraulic cylinder or the like may be employed as a drive source, and the system may be driven via a rack and pinion and a gear.

[Intake manifold embodiment 4]
Next, as a fourth embodiment of the present invention, a structure of a connection portion between the intake manifold 6 and the EGR pipe 27 will be described. FIG. 8 shows a cross-sectional view modeling the structure. In FIG. 8, (a) is shown in a plan view, and (b) is shown in a side view as seen from the direction of arrow Z for (a). This will be described below with reference to this figure. Note that arrows B and C shown in the figure indicate the flow directions of EGR gas and intake air, respectively.

  In the present embodiment, the function of the pipe portion 27c is substituted for the turning shaft 51 in the above-described third embodiment. That is, the outer shape of the valve body 52 has a streamline shape smoothly narrowed from the insertion portion of the turning shaft 51 toward the opposite side in a side view, as in the third embodiment. 52 is provided along the outflow direction of the outflow hole 51a, and at the same time, a through hole 52a from the opposite side of the intake port 6a to the insertion hole of the turning shaft 51 is provided in the valve body 52. .

  The swivel shaft 51 is formed of a pipe structure having a cavity inside, and both end portions are pivotally supported by the intake manifold 6 via ball bearings 46 and the like as in the third embodiment, and are fixed at one end portion. The drive force of the drive motor 45 is transmitted by the provided gear 47 and the swing angle of the valve body 52 is controlled. Here, one end portion where the gear 47 is fixed is further extended, and is connected to the EGR pipe 27 via a joint member such as a swivel joint 53 provided with a ball bearing. The other end is closed with a seal tape, a plug or the like (not shown) in order to prevent the release of EGR gas to the outside of the intake manifold 6. Further, the swivel shaft 51 has a plurality of outflow holes 51a drilled toward the intake port 6a side in accordance with the arrangement of the intake ports 6a to each cylinder on one side surface of the central portion, and the other one side surface. Is provided with a key groove 48 for fixing the valve body 52.

  By adopting such a configuration, the EGR gas guided by the EGR pipe 27 passes through the through hole 52a of the valve body 52 and is reliably supplied to the intake port 6a. The disturbed intake air intersects with the downstream side of the intake port 6a and then mixed by Karman vortex, so that the mixing ratio is made uniform. Further, since the pipe portion 27c to be inserted into the intake manifold 6 is not necessary, the cost is improved by reducing the number of parts.

  In the present embodiment, the single through hole 52a provided in the valve body 52 is configured. However, the present invention is not limited to this. For example, a plurality of through holes 52a are arranged in the axial direction of the turning shaft 51. May be arranged in parallel with each other to achieve dispersion after discharging the EGR gas. The actuator of the swirl control mechanism 43 is not limited to a motor but may be a cylinder or a solenoid, and the power transmission configuration between the motor and the turning shaft is not limited to a gear but may be a chain or the like. Or the structure which drives directly may be sufficient.

1 is a front perspective view showing the overall configuration of an engine according to an embodiment of the present invention. Similarly rear perspective view. The front view which shows the internal structure of an engine. It is the figure which showed the circulation passage and the intake manifold which provided the blade body which concerns on this invention in the clearance gap, (a) in this figure is sectional drawing which modeled the whole structure, (b) from the cross section X Detailed view seen. It is the figure which showed the structure of the conventional intake manifold, (a) in this figure is sectional drawing which modeled the whole structure, (b) is the detailed figure seen from the cross section a. Sectional drawing which modeled the vicinity of the intake inlet of the intake manifold which promoted the mixing of the EGR gas by the wall portion suspended from the EGR gas inlet according to the present invention to the intake flow side. FIG. 2 is a view showing a pipe-shaped recirculation passage provided with a swingable valve body at an intake port inlet portion and an intake manifold according to the present invention, in which (a) in FIG. (B) is a detailed view seen from the cross-section Y. It is the figure which showed the pipe-shaped recirculation channel | path and the intake manifold which were integrated with the swingable valve body which concerns on this invention, (a) in this figure is sectional drawing which modeled the whole structure, ( (B) is a detailed view seen from the cross section Z.

Explanation of symbols

6 Intake manifold 26 EGR valve 27 EGR pipe 28 Intake pipe 41 Gasket 6a Intake port 6b Inlet 41a Incision 41b Blade body B Flow direction of EGR gas C Intake air flow direction

Claims (7)

  In an internal combustion engine in which a circulation passage is formed between an intake manifold and an exhaust manifold so that a part of the exhaust gas is circulated to the intake side, a blade body is provided at an EGR gas inlet of the intake manifold. Internal combustion engine.   The internal combustion engine according to claim 1, wherein the blade body is formed integrally with a gasket interposed between the intake manifold and the circulation passage.   3. The blade body according to claim 1 or 2, wherein a plurality of fins are arranged in an inclined manner centering on the axis of the circulation passage and the passing EGR gas is a swirl flow. The internal combustion engine described in 1.   In an internal combustion engine in which a circulation passage is formed between the intake manifold and the exhaust manifold to circulate a part of the exhaust gas to the intake side, an EGR gas inlet is provided in the vicinity of the air inlet of the intake manifold, and the EGR An internal combustion engine characterized in that a wall portion protruding toward the intake air flow side is provided on the downstream side of the gas inlet.   In an internal combustion engine in which a circulation passage is formed between the intake manifold and the exhaust manifold to circulate a part of the exhaust gas to the intake side, the end of the circulation passage is configured in a pipe shape, and the pipe portion of the end of the circulation passage is Inserted into the intake manifold parallel to the crankshaft, drilled an outflow hole in the pipe portion according to the position of the intake port, and disposed a valve body capable of changing the angle between the pipe portion and the intake port. An internal combustion engine characterized by that.   In an internal combustion engine in which a circulation passage is formed between the intake manifold and the exhaust manifold to circulate a part of the exhaust gas to the intake side, the end of the circulation passage is configured in a pipe shape, and the pipe portion of the end of the circulation passage is Inserted into the intake manifold in parallel with the crankshaft, drilled an outflow hole in the pipe portion according to the position of the intake port, provided a valve body along the outflow direction of the outflow hole, and angled the pipe portion An internal combustion engine configured to be changeable. An internal combustion engine characterized in that one end of the pipe portion is connected to an actuator so that the angle can be changed according to the operating condition of the internal combustion engine.