JP6536655B2 - Engine intake system - Google Patents

Description

  The present invention relates to an intake system of an engine.

  In vehicles such as automobiles, an intake manifold is attached to an engine. The intake manifold includes a runner connected to the cylinder head of the engine, a surge tank connected to the intake upstream side of the runner, and a throttle valve passage connected to the intake upstream side of the surge tank for intake of fresh air And the passage). A throttle valve is attached to the intake upstream end of the throttle valve passage.

  Further, in the intake manifold disclosed in Patent Document 1 and the like, a configuration in which an EGR passage (secondary gas introduction passage) for introducing an EGR (Exhaust Gas Recirculation) gas into the throttle valve passage is connected is adopted. In the prior art, the EGR passage was connected to the throttle valve passage immediately after the throttle valve.

  As described above, by connecting the EGR passage to the position immediately after the throttle valve in the throttle valve passage, the EGR gas is smoothly made to the throttle valve passage utilizing the negative pressure generated at the portion immediately after the valve body in the throttle valve. Can be taken into

JP, 2017-31964, A

  However, in the intake manifold in which the EGR passage is connected to the position immediately after the throttle valve as described above, the water contained in the EGR gas may adhere to the throttle valve to cause condensation. As described above, when dew condensation water adheres to the throttle valve, there is a concern that the throttle valve may freeze when the outside air temperature is low (0 ° C. or lower) to cause malfunction.

  In order to suppress the malfunction of the throttle valve caused by the condensation water as described above, it is conceivable that the connection point of the EGR passage with respect to the throttle valve passage is a point away from the throttle valve. As the distance from the throttle valve to the connection point of the EGR passage becomes longer, it is considered that it becomes difficult to use the negative pressure generated at the point immediately after the valve body in the throttle valve for taking in the EGR gas.

  Therefore, if the connection point of the EGR passage in the throttle valve passage is merely a point away from the throttle valve, there is a concern that the efficiency of capturing the EGR gas into the throttle valve passage may be lowered.

  The above-described problems occur not only in the case of taking in the EGR gas into the throttle valve passage, but also in the case of taking in the purge gas and the blowby gas.

  The present invention has been made to solve the problems as described above, and can suppress the malfunction of the throttle valve even when the outside temperature is low, and at the same time, the high intake efficiency of the secondary gas into the intake air introduction passage. It is an object of the present invention to provide an engine intake system that can be secured.

An engine intake system according to an aspect of the present invention includes an intake air introduction passage having a tubular passage, and a throttle attached to one end of the intake air introduction passage and capable of changing an intake air amount by opening and closing operation of a valve body. A valve, and a secondary gas introduction passage connected to a location separated by a predetermined distance downstream of the throttle valve in the flow direction of the intake with respect to the intake introduction passage, for introducing a secondary gas into the intake introduction passage; The secondary gas introduction passage is a region along the inner wall surface of the intake air introduction passage at the location where the secondary gas introduction passage is connected, in a region where the intake flow velocity is relatively faster than the other. have a secondary gas inlet for flowing the secondary gas toward the secondary gas inlet, said from outside the intake air introducing passage, inlet tube extending to diameter center portion of the passage in the inside of the intake air introducing passage Department, A distal end tube portion connected to the distal end side of the introduction tube portion, the distal end tube portion having a tube axis in a direction orthogonal to the tube axis of the introduction tube portion; Openings are respectively provided, and the secondary gas is a region where the intake flow velocity is relatively high from the diameter center portion, passing through the pipe opening of the leading end pipe portion from the introduction pipe portion. The gas flows in toward a part of the inner wall surface of the intake air introduction passage.

  In the engine intake system according to the above aspect, the connection point of the secondary gas introduction passage to the intake air introduction passage is separated from the throttle valve by a predetermined distance. Therefore, water (condensed water) contained in the secondary gas is less likely to adhere to the throttle valve than when the secondary gas introduction passage is connected immediately after the portion where the throttle valve is attached in the intake air introduction passage. For this reason, in the intake system of the engine according to the above aspect, malfunction of the throttle valve can be suppressed even when the outside temperature is low (0 ° C. or less).

Further, in the intake system of the engine according to the above aspect, since the secondary gas is made to flow from the secondary gas introduction portion toward the region where the intake flow velocity is relatively higher than the others, the throttle valve as described above Even in the case where the secondary gas introduction passage is provided at a place separated from the place where the secondary gas is attached, the secondary gas can be made to flow into the intake air introduction passage with high efficiency. This is because the “extraction effect” can be obtained by ejecting the secondary gas toward the region where the intake flow velocity is relatively high.
Further, in the intake system of the engine according to the above aspect, since the tip end portion of the introduction pipe portion is made to be the diameter center portion of the intake introduction passage, it is more uniformly jetted toward the above "region where the intake flow velocity is relatively high". Can. Therefore, in the intake system of the engine according to the above aspect, the inflow of the secondary gas into the intake air introduction passage can be performed with higher efficiency.
Further, in the intake system of the engine according to the above aspect, the secondary gas is spouted from the two openings provided on the tip end side of the introduction pipe portion, so that no complicated configuration is required, and it is possible to reliably perform the secondary It is possible to eject the gas toward the "region where the intake flow velocity is relatively high".
Further, in the intake system of the engine according to the above aspect, the secondary gas is spouted from the pipe opening portion of the tip end pipe portion, so that the spouting direction of the secondary gas is reliably Can be turned to Therefore, in the intake system of the engine according to the above aspect, it is possible to more reliably ensure the high uptake efficiency of the secondary gas into the intake air introduction passage.

  The "region where the intake flow velocity is relatively high" in the above refers to the type and mounting form of the throttle valve, and the form of the intake introduction passage between the throttle valve and the connection point of the secondary gas introduction passage. It is set.

  The intake system of an engine according to another aspect of the present invention is the above aspect, wherein the throttle valve is a butterfly valve having the valve body and an outer pipe surrounding the outside of the valve body, the intake flow rate The region where the velocity is relatively fast is the flow direction downstream of the intake air with respect to the region including the portion where the gap between the valve body and the inner wall surface of the outer pipe is the largest when the It is an area located on the side.

  In the engine intake system according to the above aspect, the "region where the intake flow velocity is relatively high" is specifically identified as described above. In the intake system of the engine according to the above aspect, the secondary gas is obtained based on the finding that the intake flow velocity becomes the fastest at the downstream side of the location where the gap between the valve body and the inner wall surface of the outer pipe in the butterfly valve is the largest. It defines the ejection direction of secondary gas from the introductory part. Thus, in the intake system of the engine according to the above aspect, the secondary gas can be made to flow into the intake air introduction passage with high efficiency by utilizing the suction effect.

  The intake system for an engine according to another aspect of the present invention is the above aspect, wherein the engine has a plurality of cylinders, is connected to the other end of the intake air introduction passage, and internally distributes intake air to each cylinder And a plurality of independent intake passages each connected at one end to the intake distribution portion and at the other end connected to each intake port of the engine; The extending direction of the introduction passage and the arrangement direction of the connection points of the plurality of independent intake passages in the intake distribution unit are along each other, and in the arrangement direction, the intake introduction passage in the intake distribution unit The connection point is a point farthest from the one end in the intake air introduction passage.

  In the intake system of the engine according to the above aspect, since the connection location of the intake air introduction passage in the intake air distribution unit is the location farthest from the throttle valve in the extending direction of the intake air introduction passage, the secondary gas in the intake air introduction passage The flow passage length from the connection point of the introduction passage to the intake air distribution unit can be secured as long as possible. Therefore, in the engine intake system according to the above aspect, the mixing performance of the fresh air and the secondary gas can be improved.

  The intake system of an engine according to another aspect of the present invention is the above aspect, wherein a section between at least the one end of the intake introduction passage and a point where the secondary gas introduction passage is connected is linear. It is formed.

  In the intake system of the engine according to the above aspect, since the section from the at least one end of the intake air introduction passage to the connection point of the secondary gas introduction passage is formed in a straight line, the flow velocity decrease in the intake air flow in the area It can be suppressed. Therefore, in the intake system of the engine according to the above aspect, the secondary gas can be taken in more smoothly to the intake air introduction passage.

  In the intake system of the engine according to each of the above aspects, malfunction of the throttle valve can be suppressed even when the outside temperature is low, and high efficiency of secondary gas intake into the intake air introduction passage can be secured.

FIG. 2 is a schematic side view showing an engine and an intake manifold mounted in an engine room of a vehicle according to the embodiment. It is a model front view showing composition of an intake manifold. It is a model rear view which shows the structure of an intake manifold. It is a model side view showing composition of an intake manifold. It is a figure which shows the VV cross section of FIG. 4, Comprising: It is a schematic cross section which shows the internal structure of an intake manifold. It is a figure which shows the VI-VI cross section of FIG. 5, Comprising: It is a schematic cross section which shows the structure of the gas injection part of an EGR passage. It is a figure which shows the VII-VII cross section of FIG. 5, Comprising: It is a schematic cross section which shows the internal structure of an intake manifold. It is a figure which expands and shows the B section of FIG. 5, Comprising: It is a schematic cross section which shows a part of internal structure of an intake manifold. FIG. 9 is an enlarged view of a portion D of FIG. 8, and is a schematic cross-sectional view showing a connection portion of a reflux passage portion to a throttle valve passage in an intake manifold. It is a figure which shows the XX cross section of FIG. 5, Comprising: It is a schematic cross section which shows the shape of a reflux passage part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The form described below is an aspect of the present invention, and the present invention is not limited to the following form except for the essential configuration.

  In the drawings used in the following description, "Up" above the vehicle, "Lo" below the vehicle, "Fr" ahead of the vehicle, "Re" behind the vehicle, "Le" behind the vehicle, "Ri" vehicle The right side is shown respectively.

[Embodiment]
1. Engine 3 and intake manifold 7 in vehicle 1
The arrangement of the engine 3 and the intake manifold 7 in the vehicle 1 according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 1, an engine 3 is mounted in an engine room 2 provided in a fluorocarbon part of the vehicle 1. In the vehicle 1 according to the present embodiment, a four-cylinder gasoline engine is applied as an example of the engine 1. The engine 1 is mounted such that its cylinder row direction is in the front-rear (Fr-Re) direction of the vehicle 1. That is, the vehicle 1 according to the present embodiment has the engine 1 mounted vertically.

  A transmission 4 is attached to the engine 3 on the rear Re side of the vehicle 1, and a propeller shaft 5 extends from the transmission 4 toward the rear Re of the vehicle 1. A radiator 6 is provided on the front Fr side of the vehicle 1 with respect to the engine 3.

  Further, an intake manifold (intake device) 7 is attached to the engine 7. The intake manifold 7 is disposed on the left side Le of the vehicle 1 (the front side in FIG. 1).

Here, in the longitudinal direction (Fr-Re) of the vehicle 1, in the engine 3, the axis (output axis) Ax _{3 of the} engine 3 is inclined at an angle θ ₃ with respect to the horizontal axis Ax ₀ . Also, with the inclination of the engine 3, for the intake manifold 7 are inclined drives out angle theta ₇ with respect to the axis Ax ₇ is a horizontal axis Ax ₀ before and after (Fr-Re) direction of the vehicle 1.

In the present embodiment, the angle theta ₃ and the angle theta ₇ is the same angle.

2. External Configuration of Intake Manifold 7 The external configuration of the intake manifold 7 will be described with reference to FIGS. 2 to 4. 2 is a schematic front view of intake manifold 7 viewed from the left side Le of vehicle 1, FIG. 3 is a schematic rear view of intake manifold 7 viewed from the side of engine 3, and FIG. 4 is an intake FIG. 2 is a schematic side view of the manifold 7 as viewed from the front Fr side of the vehicle 1;

  As shown in FIG.2 and FIG.4, the intake manifold 7 which concerns on this embodiment has three structural members 7A-7C. Each of the three component members 7A to 7C is formed, for example, using a resin material. The number and shape of the constituent members constituting the intake manifold 7 are not limited to this.

  As shown in FIGS. 2 to 4, the intake manifold 7 includes a throttle valve passage (intake air introduction passage) 8, a plurality (four in the present embodiment) runners (independent air intake passages) 9, and a surge tank (intake air passage). A distribution unit) 10, a throttle valve 11, and an EGR valve 12 are provided. In the following description, the throttle valve may be described as "T / V" and the throttle valve passage may be described as "T / V passage".

  As shown in FIGS. 2 and 3, the T / V 11 is attached to the end of the T / V passage 8 on the front Fr side of the vehicle 1. As shown in FIG. 4, the T / V 11 includes an outer pipe 11g, a rotary shaft 11b fixed so as to extend in the radial direction of the outer pipe 11g, and a valve body 11a rotatable about the rotary shaft 11b. And a butterfly valve for adjusting the inflow of intake air to the engine 3.

  As shown in FIG. 3, the end on the rear Re side of the vehicle 1 in the T / V passage 8 is connected to the surge tank 10. The connection point of the T / V passage 8 in the surge tank 10 is the point on the rear Re side in the front-rear direction (Fr-Re) of the vehicle 1.

  As described above, the surge tank 10 is inclined so that the bottom surface portion becomes lower Lo as it goes from the front side Fr to the rear side Re along with the inclined arrangement of the intake manifold 7.

  Returning to FIG. 2, each of the four runners 9 is a passage for sending the intake air distributed by the surge tank 10 to each intake port of the engine 3. The four runners 9 according to the present embodiment are integrally molded. By this, the rigidity can be improved.

  As shown in FIG. 4, the four runners 9 arc in such a manner as to surround the left Le and the upper Up of the surge tank 10 in a side view from the front Fr side (direction perpendicular to the paper surface) of the vehicle 1. It is drawn and structured. As shown in FIG. 3, each of the four runners 9 is provided with outlet side openings 9 a to 9 d for connecting to respective intake ports of the engine 3.

  In the present embodiment, although one outlet side opening 9a to 9d is provided corresponding to each cylinder of the engine 3, the present invention is not limited to this, and two or more outlet sides corresponding to each cylinder An opening may be provided.

  As shown in FIGS. 3 and 4, the EGR valve 12 is disposed at a portion on the upper side of the intake manifold 7. An EGR passage connected to the T / V passage 8 is connected to the EGR valve 12. This will be described later.

3. Internal Configuration of Intake Manifold 7 The internal configuration of the intake manifold 7 will be described using FIGS. 5 to 7. 5 is a schematic cross sectional view showing a V-V cross section of FIG. 4, FIG. 6 is a schematic cross sectional view showing a VI-VI cross section of FIG. 5, and FIG. 7 is a VII-VII cross section of FIG. It is a schematic cross section which shows.

  As shown in FIG. 5, in the T / V passage 8, an upstream passage portion 8a and a downstream passage portion 8b are formed continuously as an intake passage between the T / V 11 and the surge tank 10, respectively. There is. An outlet side opening 13a of an EGR passage (secondary gas introduction passage) 13 connected to the EGR valve 12 (see FIGS. 3 and 4) is opened in the T / V passage 8.

  As shown in part A of FIG. 5, the T / V 11 rotates between the ceiling surface 11c and the bottom surface 11d on the inner surface of the outer pipe 11g by the rotation of the valve body 11a around the rotation axis 11b. The gaps 11e and 11f will be open. Fresh air is introduced into the T / V passage 8 through the gaps 11e and 11f.

  Here, the openings 11e and 11f have the largest opening degree in the direction orthogonal to the direction in which the rotation shaft 11b extends (the direction perpendicular to the paper surface). For this reason, the intake flow velocity of the fresh air to be introduced becomes the fastest at the ceiling surface 11c and the bottom surface 11d of the outer pipe 11g. Further, along with this, also in the T / V passage 8, the intake air flow velocity becomes relatively faster at the passage ceiling surface 8d and the passage bottom surface 8e.

  As shown in FIG. 5, the gas injection portion (secondary gas introduction portion) 13 a of the EGR passage 13 is provided at a substantially middle position in the longitudinal direction (direction along the flow of intake air) in the T / V passage 8 There is.

  As shown in FIG. 6, the gas injection part 13a has an introduction pipe part 13b provided so as to insert the pipe wall of the T / V passage 8 in and out, and a tip pipe joined to the tip part of the introduction pipe part 13b. And 13c. The introduction pipe portion 13 b is connected to the EGR passage 13. Further, the introduction pipe portion 13 b is inserted toward the radial direction central portion of the T / V passage 8.

The tip end pipe portion 13 c is provided such that the pipe axis Ax ₁₃ is orthogonal to the introduction pipe portion 13 b and substantially coincides with the pipe axis of the T / V passage 8. The upper portion Up and the lower portion Lo of the distal end tube portion 13c are open (upward opening 13d, downward opening 13e). The upward opening 13 c is opened toward a ceiling area Ar 1 which is an area along the passage ceiling surface 8 d in the T / V passage 8. Similarly, the downward opening 13 e is open toward the bottom area Ar 2 which is an area along the passage bottom 8 e in the T / V passage 8.

  The ceiling area Ar1 and the bottom area Ar2 to which the upward opening 13d and the downward opening 13e face are both areas where the intake flow velocity is relatively high.

  Referring back to FIG. 5, in the present embodiment, the passage portion of the T / V passage 8 is referred to as the upstream passage portion 8 a on the intake upstream side of the gas ejection portion 13 a of the EGR passage 13 and the intake downstream side is on the downstream side. It will be called passage part 8b. Note that, in the present embodiment, the upstream side passage portion 8a is formed in a linear shape, and the downstream side passage portion 8b is also formed in a linear shape except the connection portion to the surge tank 10.

  Further, in the T / V passage 8, a straightening unit 8 c is provided at a location corresponding to the lower side Lo of the gas ejection unit 13 a of the EGR passage 13. The straightening unit 8c is configured with a slope that rises upward to the Up side as going from the front side to the rear side. The role played by the rectifying unit 8c will be described later.

  As described above, the T / V passage 8 is connected to the surge tank 10 at the end farthest from the end where the T / V 11 is attached (the farthest point). Specifically, the T / V passage 8 is connected at the rearmost Re side of the surge tank 10.

  The surge tank 10 is internally provided with a surge tank interior space 10a. The surge tank inner space 10 a is in communication with the downstream side passage portion 8 b of the T / V passage 8. Further, in the surge tank 10, inlet side openings 9i to 9l connected to the respective passage portions 9e to 9h of the runner 9 are opened. Thus, the surge tank inner space 10a is also communicated with the passage portions 9e to 9h of the runner 9.

As shown in FIG. 7, the bottom P ₁ of the surge tank 10 is configured drives out smooth curved surface. Then, (in FIG. 6, for convenience of illustration, illustrated only inlet-side opening 9k.) Inlet-side opening 9i~9l runner 9 lower Lo-side portion of the so that the bottom portion P ₁ and substantially flush (See the portion indicated by arrow C). The passage portions 8 a and 8 b of the T / V passage 8 are configured to point to the bottom portion P ₁ of the surge tank 10.

Here, as described with reference to FIG. 1, the intake manifold 7 of the present embodiment, the following angle theta ₇ with respect to the axis Ax ₇ is a horizontal axis Ax ₀ before and after (Fr-Re) direction of the vehicle 1 It is inclined. Therefore, for the bottom P ₁ of the surge tank 10, the front and rear of the vehicle 1 (Fr-Re) direction, i.e., is inclined by an angle theta ₇ along the cylinder row direction of the engine 1.

  Therefore, as shown in FIG. 5, the inlet side openings 9i to 9l are arranged below the vehicle 1 in the order from the inlet side opening 9i to the inlet side opening 9j, the inlet side opening 9k and the inlet side opening 9l. It is arranged on the Lo side.

  In the surge tank 10, a reflux passage portion 10b is formed, which communicates the portion on the forward Fr side in the surge tank inner space 10a with the downstream passage portion 8b in the T / V passage 8. In the reflux passage portion 10b, the lower Lo side is in the upper portion of the surge tank 10 where the inlet side openings 9j and 9i are opened, and the upper Up side is the rectifying portion 8c in the T / V passage 8. It is just downstream of the place provided.

4. Airflow in Intake Manifold 7 Airflow in the intake manifold 7 will be described with reference to FIGS. 6 to 8. FIG. 8 is a schematic cross-sectional view showing a portion B of FIG. 5 in an enlarged manner.

  As shown in FIG. 8, fresh air (air) introduced according to the opening degree of the valve body 11 a in the T / V 11 makes the upstream side passage portion 8 a of the T / V passage 8 downstream (rear Re side) Flow toward (airflow Flow 2). As described above, the air flow Flow2 includes the air flow Flow21 flowing along the passage ceiling surface 8d and the air flow Flow22 flowing along the passage bottom surface 8e. In these air flows Flow 21 and Flow 22, the intake flow velocity is relatively faster than the other air flows in the air flow Flow 2.

  A predetermined amount of EGR gas (secondary gas) is ejected from the gas ejection portion 13a of the EGR passage 13 to the downstream passage portion 8b of the T / V passage 8 according to the valve opening degree of the EGR valve 12 (EGR gas Flow Flow 3). As shown in FIG. 6, the EGR gas flow Flow 30 flowing through the introduction pipe portion 13 b has an EGR gas flow Flow 31 ejected toward the ceiling area Ar 1 from the upward opening 13 d and a bottom portion from the downward opening 13 e. The EGR gas flow Flow 32 which is jetted toward the region Ar2 is branched.

  Referring back to FIG. 8, the EGR gas flows Flow 31 and Flow 32 spouted from the both openings 13 d and 13 e are a fresh air flow Flow 2 (airflows Flow 21 and Flow 22) sent from the upstream passage portion 8 a of the T / V passage 8. Flow toward the downstream side (rear Re side) (air flow Flow 4).

  The gas (fresh air + EGR gas) mixed while advancing the downstream side passage portion 8 b is introduced into the space 10 a in the surge tank 10 (air flow Flow 5).

  The air flow Flow 5 flows along the inner wall surface of the surge tank 10 a, and the gas is temporarily accumulated in the space 10 a in the surge tank 10. As a result, the gas is evenly distributed to the inlet openings 9i to 9l of the runners 9, and the intake buffer is also prevented.

  From the surge tank 10, gas is drawn out to each runner 9 through the inlet side openings 9i to 9l (air flow Flow 6). Further, from the surge tank 10, at least a part of the gas (fresh air, EGR gas) is recirculated to the downstream passage 8b of the T / V passage 8 through the reflux passage 10b (air flow Flow 7). The recirculated gas (fresh air, EGR gas) is again mixed in the downstream passage portion 8 b and sent to the surge tank inner space 10 a of the surge tank 10.

  As shown in FIG. 7, the runner 9 is connected to the runner 9 via the inlet space 9a of the surge tank 10 via the inlet openings 9i to 9l (only the inlet opening 9k is shown in FIG. 7 for convenience of illustration). The sent gas (mixed gas of fresh air and EGR gas) is sent from the passage portions 9e to 9h of the runner 9 to the intake port of the engine 3 through the outlet side openings 9a to 9d (air flow Flow1).

  In FIG. 7, for the convenience of illustration, only the passage 9g in the passages 9e to 9h is illustrated, and only the outlet opening 9c in the outlet openings 9a to 9d is illustrated.

5. Role played by the rectifying unit 8c The role played by the rectifying unit 8c provided on the inner wall surface of the T / V passage 8 will be described with reference to FIG. FIG. 9 is a schematic cross-sectional view showing a portion D of FIG. 8 in an enlarged manner.

  As shown in FIG. 9, the straightening portion 8c in the T / V passage 8 has a triangular cross-sectional shape, and is upwardly directed from the intake upstream side (front Fr side) to the intake downstream side (rear Re side) It is formed to be raised (see the portion indicated by arrow E).

  Of the inner wall surface surrounding the upstream side passage portion 8a in the T / V passage 8, the rectifying portion 8c is a fresh air (air flow Flow 22) flowing along the bottom surface 8e which is the inner wall surface on the bottom side (lower Lo side). It is deflected upward to the Up side (air flow Flow 8). The airflow Flow 8 is a flow avoiding the opening of the reflux passage portion 10 b.

  As described above, in the intake manifold 7 according to the present embodiment, the rectifying portion 8c of the T / V passage 8 can enhance the effect of making the outlet portion of the reflux passage portion 10b a negative pressure. Therefore, in the intake manifold 7, it is possible to promote the reflux to the T / V passage 8 through the reflux passage portion 10b, and it is possible to improve the mixing performance.

In the present embodiment, the angle θ ₈ c of the straightening portion 8 c (inclined surface) with respect to the bottom surface 8 e is in the range of 10 ° to 45 °, and more preferably in the range of 20 ° to 35 °.

6. Configuration of Reflux Passage 10b The configuration of the reflux passage 10b will be described with reference to FIGS. 9 and 10. FIG. FIG. 10 is a schematic cross-sectional view showing the XX cross section of FIG.

As shown in FIG. 9, in the reflux passage portion 10b provided so as to connect the surge tank internal space 10a of the surge tank 10 and the downstream passage portion 8b of the T / V passage 8, the tube axis Ax ₁₀ is at the top It is provided to turn diagonally backward as you go. Angle theta ₁₀ formed by the tube axis Ax ₈ of the downstream passage portion 8b of the tube axis _{Ax 10} and T / V passage 8 of the recirculation passage portion 10b has a less than 90 °. That is, a tube axis Ax ₈ of the tube axis _{Ax 10} and T / V passage 8 of the recirculation passage section 10b are to be crossed at an acute angle.

Further, as shown in FIG. 9, the reflux passage portion 10 b is connected to the T / V passage 8 on the downstream side (rear Re side) in the flow direction of intake air from the gas ejection portion 13 a of the EGR passage 13. Specifically, a virtual line Ax ₁₃ is drawn from the center of the gas injection portion 13a of the EGR passage 13 (the tube axis of the distal end tube portion 13c) in the direction orthogonal to the tube axis Ax ₈ and the upper front end portion P of the reflux passage portion 10b _When an imaginary line Ax _{10 b} parallel to the imaginary line Ax ₁₃ is drawn from _{10 b} , the distance between the imaginary line Ax ₁₃ and the imaginary line Ax _{10 b} is D ₁₀ . The distance D10 is, for example, about ₁₀ mm to 50 mm.

  Furthermore, as shown in FIG. 9, the reflux passage portion 10 b is configured such that the connection portion (upper portion) with the T / V passage 8 faces the downstream side (rear Re side) in the direction along the flow of intake air. ing. For this reason, combined with the formation of the flow straightening unit 8c, it is suppressed that new air or EGR gas flowing through the upstream passage portion 8a of the T / V passage 8 flows back to the surge tank 10 through the reflux passage portion 10b. can do.

As shown in FIG. 10, the reflux passage portion 10b is disposed from the side (lower Lo side) of the surge tank inner space 10a of the surge tank 10 to the downstream side passage portion 8b (upper Up side) of the T / V passage 8. Directingly, the cross-sectional width inside the passage gradually decreases. Specifically, the return passage portion 10b has an inner cross-sectional width on the side of the surge tank inner space 10a of D _LO and an inner cross-sectional width of the T / V passage 8 on the downstream side passage portion 8b is D _UP . . The cross-sectional width D _LO and the cross-sectional width D _UP satisfy the following relationship.
[Equation 1] D _LO > D _UP
The cross-sectional width D _LO is the same as the width of the space 10 a in the surge tank 10 in the direction shown in FIG. 10. On the other hand, the cross-sectional width _DUP is equal to or less than the inner diameter of the downstream side passage portion 8 b of the T / V passage 8.

7. In the intake manifold (intake device) 7 of the engine 3 according to this embodiment, the gas injection portion (connection portion) 13a of the EGR passage (secondary gas introduction passage) 13 with respect to the T / V passage (intake air introduction passage) 8 is It is separated from T / V 11 by a predetermined interval. Therefore, in the intake manifold 7 according to the present embodiment, the water (condensed water) contained in the EGR gas (secondary gas) is T compared to the case where the gas ejection part of the EGR passage is provided at the position immediately after T / V. It is hard to adhere to / V11. Therefore, in the intake manifold 7 according to the present embodiment, it is possible to suppress the operation failure of the T / V 11 caused by the moisture in the EGR gas even when the outside air temperature is low (0 ° C. or less).

  Further, in the intake manifold 7 of the engine 3 according to the present embodiment, the EGR gas (secondary gas) is directed from the gas injection part 13a of the EGR passage 13 toward the regions Ar1 and Ar2 where the intake flow velocity is relatively faster than the others. Since the gas is allowed to flow in, even when the gas ejection part 13a of the EGR passage 13 is provided at a location separated from the location where the T / V 11 is attached, the EGR gas with high efficiency with respect to the T / V passage 8 (EGR gas flow Flow 3) can be introduced. This is because the "extraction effect" can be obtained by ejecting the EGR gas toward the region where the intake flow velocity is relatively high.

  In the present embodiment, as one example, the regions Ar1 and Ar2 are referred to as "regions where the intake flow velocity is relatively high." However, with respect to the regions, the type and mounting form of T / V, and gas ejection from T / V. It is suitably set according to the form etc. of the T / V passage to a part.

  Further, in the intake manifold 7 of the engine 3 according to this embodiment, the ceiling area Ar1 and the bottom area Ar2 are specifically identified as the "area where the intake flow velocity is relatively high". As described above, in the present embodiment for specifying the “region where the intake flow velocity is relatively high”, the downstream of the portion where the gaps 11e and 11f between the valve body 11a and the inner wall surface of the outer pipe 11g in T / V 11 is the largest. Based on the knowledge that the intake flow velocity is the highest at the side (rear Re side), the ejection direction of the EGR gas from the gas ejection portion 13a is defined as shown in FIGS. Thereby, in the intake manifold 7 according to the present embodiment, the EGR gas can be made to flow into the T / V passage 8 with high efficiency by utilizing the suction effect.

Further, in the intake manifold 7 of the engine 3 according to the present embodiment, as described with reference to FIG. 6, the tip of the introduction pipe portion 13 b (the pipe axis Ax ₁₃ of the tip pipe portion 13 c) Since it matches with the diameter center portion, it can be more uniformly ejected toward the ceiling area Ar1 and the bottom area Ar2. Therefore, in the intake manifold 7 according to the present embodiment, the inflow of the EGR gas into the T / V passage 8 can be performed with higher efficiency.

  Further, in the intake manifold 7 of the engine 3 according to the present embodiment, the end pipe portion 13c orthogonal to the introduction pipe portion 13b is joined to the end of the introduction pipe portion 13b, and the EGR gas is passed through the two openings 13d and 13e. Since the spouting configuration is adopted, EGR gas can be reliably spouted toward the ceiling portion area Ar1 and the bottom portion area Ar2, without requiring a complicated configuration.

  Further, in the intake manifold 7 of the engine 3 according to the present embodiment, the EGR gas is ejected from the openings 13d and 13e of the end pipe portion 13c of the gas ejection portion 13a. Therefore, the ejection direction of the EGR gas is ensured. It can be directed to the ceiling area Ar1 and the bottom area Ar2. Therefore, in the intake manifold 7 according to the present embodiment, it is possible to more reliably ensure the high uptake efficiency of the EGR gas into the T / V passage 8.

  Further, in the intake manifold 7 of the engine 3 according to this embodiment, the connection location of the T / V passage 8 in the surge tank 10 is taken as the location farthest from the T / V 11 in the extension direction of the T / V passage 8 Therefore, the flow path length from the location where the gas injection portion 13 a is disposed in the T / V passage 8 to the surge tank 10 can be secured as long as possible. Therefore, in the intake manifold 7 according to this embodiment, the mixing performance of the fresh air and the secondary gas can be improved.

  Further, in the intake manifold 7 of the engine 3 according to the present embodiment, at least the upstream passage portion 8a in the T / V passage 8 is formed in a straight line, so the flow velocity decrease in the intake flow in the upstream passage portion 8a. Can be suppressed. Therefore, in the intake manifold 7 according to the present embodiment, the EGR gas can be more smoothly taken into the T / V passage 8.

  As described above, in the intake manifold 7 of the engine 3 according to the present embodiment, the malfunction of the T / V 11 can be suppressed even when the outside temperature is low, and the high uptake efficiency of the EGR gas into the T / V passage 8 It can be secured.

[Modification]
In the above embodiment, a 4-cylinder gasoline engine is adopted as the engine 3, but the present invention is not limited to this. For example, a gasoline engine with three or less cylinders or five or more cylinders may be employed. Also, instead of a gasoline engine, a diesel engine can be adopted.

  In the above embodiment, the engine 3 is mounted vertically and an FR vehicle that drives a rear tire is adopted as an example, but the present invention is not limited to this. For example, it is also possible to adopt an FF car with an engine set horizontally to the engine room.

  In the above embodiment, a pipe body in which both the upstream passage portion 8a and the downstream passage portion 8b extend linearly as the T / V passage 8 is adopted, but the present invention is not limited to this. . For example, a tube whose downstream side passage portion is curved in a U-shape can be adopted as the T / V passage.

  In the above embodiment, a butterfly valve is employed as an example of the T / V 11, but the present invention is not limited to this. For example, a gate valve can also be employed. Also in this case, the upper similar effect can be obtained by defining the ejection direction of the secondary gas in consideration of “a region where the intake flow velocity is relatively high” corresponding to the type of valve.

  In the above embodiment, as described with reference to FIG. 5, when the surge tank 10 is viewed from the right side Ri of the vehicle 1, the space 10a in the surge tank has a substantially rectangular shape, but The present invention is not limited to this. For example, it is also possible to employ a surge tank having a circular or elliptical shape, or a surge tank internal space having a shape in which a portion thereof is cut away.

  In the above embodiment, as described with reference to FIG. 6, in the tip pipe portion 13c of the gas jet portion 13a, the upward opening 13d faces upward and the downward opening 13e faces downward Lo. However, the present invention is not limited thereto. Depending on the configuration and arrangement of the T / V 11 and the like, the left side Le side or the right side Ri side of the T / V passage 8 can be made to face the opening. That is, the secondary gas may be jetted toward the point where the flow velocity is the highest at the portion where the gas jet portion of the T / V passage is provided. Thereby, the same effect as described above can be obtained.

  In the above embodiment, the gas injection portion 13a is configured by a combination of the introduction pipe portion 13b and the end pipe portion 13c connected to the tip end portion, but the present invention is not limited thereto. It is not something to receive. For example, the tip of the introduction tube may be closed, and a hole for gas ejection may be provided in the vicinity of the tip. Moreover, the structure etc. which inserted and joined the some branch pipe with respect to the introductory pipe part are also employable.

  Although the EGR gas as an example of the secondary gas is returned to the T / V passage 8 in the above embodiment, the present invention is not limited to this. For example, a secondary gas such as a purge gas or a blowby gas may be returned to the T / V passage.

In the above embodiment, a control valve or the like for controlling the flow rate is not provided in the reflux passage portion 10b, but the present invention is not limited to this. For example, a control valve may be provided to control the flow rate of gas returned from the surge tank to the T / V passage according to the engine speed, intake air amount, O ₂ concentration, and the like.

  In the above embodiment, the intake manifold 7 is configured by a combination of three components 7A to 7C, but the present invention is not limited to this. For example, a combination of two components may be used, or a combination of four or more components may be used.

  In the above embodiment, four runners 9 are integrally formed, but the present invention is not limited to this. Each runner may be provided separately, or may be integrally formed two by two.

  In the above embodiment, although the straightening section 8c is configured by a flat slope, the present invention is not limited to this. For example, it may be configured with a convex or concave curved surface.

1 Vehicle 3 Engine 7 Intake Manifold (Intake System)
8 Throttle valve passage (intake air introduction passage)
8a upstream passage portion 8b downstream passage portion 9 runner (independent intake passage)
10 Surge tank (intake distribution unit)
11 throttle valve 13 EGR passage (secondary gas introduction passage)
13a Gas ejection part (secondary gas introduction part)
13b Introductory tube portion 13c Tip tube portion 13d upward opening 13e downward opening

Claims (4)

In the intake system of the engine,
An intake air introduction passage having a tubular passage;
A throttle valve attached to one end of the intake air introduction passage and capable of changing an intake air amount by opening and closing operation of a valve body;
A secondary gas introduction passage which is connected to the intake air introduction passage at a location separated by a predetermined distance downstream of the throttle valve in the flow direction of the intake air from the throttle valve and introduces a secondary gas into the intake air introduction passage;
Equipped with
The secondary gas introduction passage is directed toward the region where the flow velocity of intake air is relatively higher than that of the other regions in the region along the inner wall surface of the intake passage at the location where the secondary gas introduction passage is connected. have a secondary gas inlet for flowing secondary gas,
The secondary gas introduction portion is an introduction pipe portion extending from the outside of the intake air introduction path to a radial center portion of the path inside the intake air introduction path, and the introduction pipe connected to the tip end side of the introduction pipe portion A distal end tube portion having a tube axis in a direction orthogonal to the tube axis of the portion;
Tube openings are provided on both sides in the tube axial direction of the distal end tube portion,
The secondary gas passes from the introduction pipe portion to the pipe opening portion of the tip end pipe portion, and is a region having a relatively high intake flow velocity from the diameter center portion, which is one of the inner wall surfaces of the intake introduction passage. Inflow toward the department,
Engine intake system. An engine intake system according to claim 1, wherein
The throttle valve is a butterfly valve having the valve body and an outer pipe surrounding the outside of the valve body,
The region where the intake flow velocity is relatively high is a region where the clearance between the valve body and the inner wall surface of the outer pipe is the largest when the valve body is in an open state. An area located downstream in the flow direction,
Engine intake system. An intake system for an engine according to claim 1 or 2 , wherein
The engine has a plurality of cylinders,
An intake distribution unit which is a container connected to the other end of the intake introduction passage and having a space for distributing intake to each cylinder inside;
A plurality of independent intake passages each connected at one end to the intake distribution unit and at the other end connected to each intake port of the engine;
And further
The extending direction of the intake air introduction passage and the arrangement direction of the connection points of the plurality of independent air intake passages in the intake air distribution unit are in a state of being along each other,
In the arrangement direction, the connection location of the intake air introduction passage in the intake air distribution unit is a location on the side farthest from the one end of the intake air intake passage.
Engine intake system. An intake system for an engine according to any one of claims 1 to 3 , wherein
In the intake air introduction passage, a section from at least the one end portion to a point where the secondary gas introduction passage is connected is formed in a straight line.
Engine intake system.