Engine intake system

Abstract

To provide a suction device for an engine capable of preventing condensate water accumulated on a lower part inside a surge tank resulting from an airflow from being sent to a cylinder at once, to suppress accidental fire in the cylinder.SOLUTION: An suction device for an engine comprises a suction manifold 6. The suction manifold 6 has a plurality of runners, a surge tank 62, and a suction introduction passage 61. The surge tank 62 has a space in which the plurality of runners is gathered, and is provided so that runner introduction ports of each of the plurality of runners are aligned along a predetermined direction. The suction introduction passage 61 is a passage for introducing air into the surge tank 62. A side wall inner surface 62h of the surge tank 62 is provided with a deflection base part 62i that deflects the flow of air flowing along the side wall inner surface 62h toward the runner introduction ports after passing above a lower wall inner surface 62a of the surge tank 62.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an intake system for an engine. [Background technology]

[0002] Some vehicle engines are equipped with an EGR (Exhaust Gas Recirculation) device that recirculates part of the exhaust gas back into the intake air. By adding an EGR device like this, it is possible to suppress an excessive rise in the combustion gas temperature, suppress the generation of nitrogen oxides (NOx), and reduce pumping losses during intake.

[0003] The fresh air and EGR gas sent from the intake manifold to each cylinder of the engine contain moisture. The moisture contained in the fresh air and EGR gas can accumulate as condensed water in the lower part of the intake manifold. If this accumulated condensed water is sent to a cylinder, it may cause a misfire in that cylinder.

[0004] Patent Document 1 discloses an intake manifold that has a receiving portion provided at the inlet of the surge tank to receive condensed water, and a guide surface portion provided inside the surge tank to guide the received condensed water in the direction of cylinder alignment and gradually drip it to the bottom of the surge tank. By adopting the above-mentioned configuration, the intake manifold disclosed in Patent Document 1 attempts to prevent a large amount of condensed water from being sent to a specific cylinder all at once. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-286069 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the technology disclosed in Patent Document 1, it is conceivable that the flow of fresh air and EGR gas may scoop up the condensed water accumulated at the bottom of the surge tank, causing a large amount of condensed water to be sent to the cylinders all at once.

[0007] Furthermore, since the fresh air sent to the intake manifold also contains moisture, it is conceivable that the problem of misfires due to condensed water being sent to the cylinders could also occur in engines that do not have an EGR device.

[0008] The present invention aims to provide an engine intake device that can prevent condensed water that has accumulated in the lower part of a surge tank due to air flow from being sent all at once to a cylinder, thereby preventing misfires in that cylinder. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided an intake system for an engine, comprising an engine body and an intake manifold. The engine body has a cylinder head with a plurality of cylinders and an intake port formed therein, which is connected to each of the plurality of cylinders. The intake manifold allows air to pass through to the plurality of intake ports in the engine body.

[0010] The intake manifold has a plurality of independent intake passages, a surge tank, and an intake introduction passage. The plurality of independent intake passages are arranged along the cylinder row direction in the engine body and are connected to the plurality of intake ports, respectively. The surge tank has a space where the plurality of independent intake passages are gathered, and is a portion provided so that the openings of the plurality of independent intake passages are aligned in a predetermined direction. The intake introduction passage is the surge tank is formed to extend from one end side to the other end side along the predetermined direction, and is connected to the space of the surge tank at the other end side, A passage for introducing air into the surge tank.

[0011] In the engine intake system according to this aspect, the intake air introduction passage and the space in the surge tank are separated by a partition wall except for the communicating portion at the other end. Also,In the engine intake system according to this aspect, the surge tank has a deflection base portion provided on the inner surface of the side wall that faces the side wall in which the plurality of openings are provided, with the space therebetween. In a range facing the plurality of openings in the predetermined direction, the protrusions are provided so as to protrude from the inner surface of the opposing side wall toward the plurality of openings, and the protrusion height toward the space side gradually increases from top to bottom, The air flowing along the inner surface of the side wall is deflected so that it passes above the inner surface of the lower wall of the surge tank and flows toward at least some of the plurality of openings.

[0012] In the engine intake system according to the above aspect, the deflection base is provided on the inner surface of the side wall of the surge tank in the intake manifold, so that the air flowing along the inner surface of the side wall passes above the inner surface of the lower wall. As a result, the engine intake system according to the above aspect can prevent condensed water that has accumulated on the inner surface of the lower wall of the surge tank from being suddenly introduced into the independent intake passage. Therefore, the engine intake system according to the above aspect can prevent a large amount of condensed water from being suddenly introduced into a cylinder, thereby preventing misfires in that cylinder.

[0014] Also, In the engine intake device according to the above aspect, a partition is provided between the intake air introduction passage and the space in the surge tank, so the passage length of the intake air introduction passage can be ensured. However, it is thought that increasing the passage length may make it easier for condensed water that has accumulated on the inner surface of the lower wall of the surge tank to be scooped up due to changes in the air flow within the surge tank.

[0015] However, in the engine intake device according to the above aspect, since the deflection base is provided on the inner surface of the side wall of the surge tank, it is possible to prevent the condensed water accumulated on the inner surface of the lower wall of the surge tank from being scooped up by the air flow, and therefore the engine intake device according to the above aspect is suitable for preventing misfires in cylinders caused by condensed water.

[0017] Also,In the engine intake device according to the above aspect, a deflection base portion is provided on the inner surface of the side wall of the surge tank, and the protruding height toward the space gradually increases as it goes from top to bottom, thereby ensuring that the air flowing along the inner surface of the side wall passes above the inner surface of the lower wall.

[0018] Furthermore, in the engine intake device according to the above aspect, the deflection base portion of the surge tank is provided in an area that includes a range facing multiple openings (openings that connect to multiple independent intake passages), thereby preventing a situation in which a large amount of condensed water is introduced into the cylinders all at once from the independent intake passages.

[0019] In the engine intake device according to the above aspect, the surge tank may further have a deflection protrusion that is provided on the deflection base and deflects the flow of air flowing through the space of the surge tank from the other end side to the one end side toward the multiple openings.

[0020] In the engine intake device according to the above aspect, a deflection protrusion is further provided on the deflection base portion, so that air flowing along the inner surface of the side wall can be reliably guided to each opening while passing above the inner surface of the lower wall. According to another aspect of the present invention, there is provided an intake system for an engine, comprising an engine body and an intake manifold. The engine body has a cylinder head having a plurality of cylinders and an intake port connected to each of the plurality of cylinders. The intake manifold allows air to pass through to the plurality of intake ports in the engine body. The intake manifold has a plurality of independent intake passages, a surge tank, and an intake introduction passage. The plurality of independent intake passages are aligned along the cylinder row direction in the engine body and connected to each of the plurality of intake ports. The surge tank has a space where the plurality of independent intake passages are gathered, and is a portion provided so that openings of the plurality of independent intake passages are aligned along a predetermined direction. The intake introduction passage is formed to extend from one end to the other end of the surge tank along the predetermined direction, is connected to the space in the surge tank at the other end, and is a passage for introducing air into the surge tank. In the engine intake system according to this aspect, the surge tank has a deflection base provided on the inner surface of a side wall that faces the side wall having the plurality of openings with the space therebetween, and a deflection protrusion provided on the deflection base for deflecting the air flow that flows through the space of the surge tank from the other end side to the one end side toward the plurality of openings. The deflection base deflects the air flow that flows along the inner surface of the side wall so that it passes above the inner surface of the lower wall of the surge tank and flows toward at least some of the plurality of openings. In the engine intake system according to the above aspect, the deflection base is provided on the inner surface of the side wall of the surge tank in the intake manifold, so that the air flowing along the inner surface of the side wall passes above the inner surface of the lower wall. As a result, the engine intake system according to the above aspect can prevent condensed water that has accumulated on the inner surface of the lower wall of the surge tank from being suddenly introduced into the independent intake passage. Therefore, the engine intake system according to the above aspect can prevent a large amount of condensed water from being suddenly introduced into a cylinder, thereby preventing misfires in that cylinder. Furthermore, in the intake device of the engine according to the above aspect, a partition is provided between the intake air introduction passage and the space in the surge tank, so the passage length of the intake air introduction passage can be ensured. However, it is thought that by increasing the passage length, changes in the air flow within the surge tank may make it easier for condensed water that has accumulated on the inner surface of the lower wall of the surge tank to be scooped up. However, in the engine intake device according to the above aspect, since the deflection base is provided on the inner surface of the side wall of the surge tank, it is possible to prevent the condensed water accumulated on the inner surface of the lower wall of the surge tank from being scooped up by the air flow, and therefore the engine intake device according to the above aspect is suitable for preventing misfires in cylinders caused by condensed water. Furthermore, the engine intake device according to the above aspect further has a deflection protrusion on the deflection base portion, so that the air flowing along the inner surface of the side wall can be reliably guided to each opening while passing above the inner surface of the lower wall.

[0021] In the engine intake device according to the above aspect, the surge tank may further have a plurality of ribs on the inner surface of the lower wall of the surge tank, extending from each of the portions between adjacent openings toward the inner surface of the opposing side wall.

[0022] In the engine intake device according to the above aspect, a plurality of ribs are provided on the inner surface of the lower wall of the surge tank so as to extend from the portions between the openings of the plurality of independent intake passages, and the movement of condensed water in the predetermined direction is restricted by the ribs. As a result, the engine intake device according to the above aspect can prevent condensed water accumulated on the inner surface of the lower wall of the surge tank from being biased downstream in the air flow direction, and can prevent a large amount of condensed water from being introduced all at once into an independent intake passage having an opening downstream in the air flow direction in the predetermined direction, thereby preventing misfires in cylinders connected to the independent intake passage.

[0023] According to another aspect of the present invention, there is provided an intake system for an engine, comprising an engine body and an intake manifold. The engine body has a cylinder head having a plurality of cylinders and an intake port connected to each of the plurality of cylinders. The intake manifold allows air to pass through to the plurality of intake ports in the engine body. The intake manifold has a plurality of independent intake passages, a surge tank, and an intake introduction passage. The plurality of independent intake passages are aligned along the cylinder row direction in the engine body and connected to each of the plurality of intake ports. The surge tank has a space where the plurality of independent intake passages are gathered, and is a portion where the openings of the plurality of independent intake passages are aligned along a predetermined direction. The intake introduction passage is a passage that is connected to the space in the surge tank at a central portion in the predetermined direction so as to be directed toward the inner surface of the lower wall of the surge tank at the portion that communicates with the space in the surge tank, and introduces air into the surge tank. In the engine intake device according to this aspect, the surge tank has a deflection base provided on the inner surface of the side wall that faces the side wall having the plurality of openings with the space therebetween, and two ribs that are provided on the inner surface of the lower wall on both sides of the deflection base in the predetermined direction, each rib extending from a portion between adjacent openings toward the inner surface of the opposing side wall. The deflection base protrudes from the inner surface of the opposing side wall toward some of the openings in a region including a central portion in the predetermined direction so as to cover an upper portion of the inner surface of the lower wall, and deflects the air flowing along the inner surface of the side wall so as to pass above the inner surface of the lower wall and flow toward at least some of the openings.

[0024] In the engine intake system according to the above aspect, the deflection base is provided on the inner surface of the side wall of the surge tank in the intake manifold, so that the air flowing along the inner surface of the side wall passes above the inner surface of the lower wall. As a result, the engine intake system according to the above aspect can prevent condensed water that has accumulated on the inner surface of the lower wall of the surge tank from being suddenly introduced into the independent intake passage. Therefore, the engine intake system according to the above aspect can prevent a large amount of condensed water from being suddenly introduced into a cylinder, thereby preventing misfires in that cylinder. Also, In the engine intake device according to the above aspect, a deflection base is provided in a region including the central portion in the predetermined direction, protruding toward some of the openings and covering an upper portion of the inner surface of the lower wall. Therefore, air introduced into the surge tank from the intake passageway strikes the deflection base and is dispersed in the predetermined direction (the flow direction is deflected). The air flow dispersed in the predetermined direction can pass above the inner surface of the lower wall of the surge tank, preventing condensed water accumulated on the inner surface of the lower wall from being introduced into the independent intake passageway through the opening in the central portion in the predetermined direction. Therefore, the engine intake device according to the above aspect can prevent misfires caused by a large amount of condensed water being introduced all at once into a specific cylinder (particularly, a cylinder connected to an independent intake passage having an opening in the central portion of the surge tank in the predetermined direction).

[0026] Also,In the engine intake device according to the above aspect, since the intake air introduction passage is connected to the space of the surge tank at the center in the predetermined direction so as to be directed toward the inner surface of the lower wall of the surge tank, the flow of air introduced from the intake air introduction passage into the surge tank is deflected in the predetermined direction. In this way, if the air flow over the condensed water accumulated on the inner surface of the lower wall of the surge tank is from the center to the ends in the predetermined direction, the condensed water will also move from the center to the ends, and it is thought that the condensed water on the inner surface of the lower wall of the surge tank will be biased toward the ends rather than the center.

[0027] However, in the engine intake device according to the above aspect, two ribs are provided on the inner surface of the lower wall in the portions on both sides where the deflection base portions are provided in the predetermined direction, and the ribs restrict the movement of condensed water in the predetermined direction. Therefore, in the engine intake device according to the above aspect, it is possible to prevent condensed water from being concentrated at both end portions of the surge tank in the predetermined direction, and to prevent a large amount of condensed water from being introduced all at once into the independent intake passages having openings near the both end portions.

[0028] In the engine intake device according to the above aspect, the intake manifold may be configured by joining a plurality of members including a first member and a second member that form the space of the surge tank by joining the inner surface of the side wall on which the plurality of openings are provided and the inner surface of the side wall on which the deflection base portion is provided in a direction facing each other.

[0029] In the engine intake device according to the above aspect, the intake manifold is formed by joining multiple components including a first component and a second component, so that it is possible to easily manufacture an intake manifold with a complex internal structure having a deflection base portion on the inner surface of the side wall of the surge tank.

[0030] In the engine intake device according to the above aspect, the plurality of openings may be provided so that lower end portions thereof are positioned above an inner surface of a lower wall of the surge tank.

[0031] In the engine intake system according to the above aspect, the openings of the independent intake passages are positioned above the inner surface of the lower wall of the surge tank, which prevents condensed water from undesirably flowing from the surge tank into the independent intake passages when the engine is stopped, thereby preventing misfires in the cylinders when the engine is restarted.

[0032] In the engine intake device according to the above aspect, each of the plurality of independent intake passages may have a portion extending upward from the opening.

[0033] In the engine intake system according to the above aspect, since each of the independent intake passages has a portion extending upward from the opening, condensed water remaining in the independent intake passages is returned to the surge tank when the engine is stopped, which is more suitable for preventing misfires in the cylinders when the engine is restarted.

[0034] In the intake system for the engine according to the above aspect, an EGR passage for introducing EGR gas may be connected to the intake manifold.

[0035] In the engine intake system according to the above aspect, the EGR passage is connected to the intake manifold, which prevents an excessive rise in combustion gas temperature, suppresses the generation of nitrogen oxides (NOx), and reduces pumping loss during intake. Meanwhile, moisture contained in the EGR gas condenses, and condensed water generated from the EGR gas accumulates on the inner surface of the lower wall of the surge tank. However, by providing a deflection base on the inner surface of the side wall of the surge tank as described above, it is possible to prevent a large amount of condensed water from being scooped up by the air flow and being introduced all at once into the opening of the independent intake passage. Therefore, in the engine intake system according to the above aspect, connecting the EGR passage to the intake manifold achieves the above effects, while also preventing misfires in cylinders caused by condensed water being sent thereto. [Effects of the Invention]

[0036] The engine intake device according to each of the above aspects can prevent condensed water that has accumulated in the lower part of the surge tank due to air flow from being sent all at once to the cylinder, thereby preventing misfires in the cylinder. [Brief explanation of the drawings]

[0037] [Figure 1] 1 is a schematic diagram showing the configuration of an engine according to a first embodiment. FIG. [Figure 2] FIG. 2 is a perspective view showing the external configuration of an intake manifold. [Figure 3] FIG. 2 is a perspective view showing the external configuration of an intake manifold. [Figure 4] FIG. 4 is a cross-sectional view showing the configuration of a cross section taken along line IV-IV in FIG. [Figure 5] FIG. 3 is a cross-sectional view showing the configuration of a cross section taken along line VV in FIG. [Figure 6] FIG. 2 is a perspective view showing a configuration of a base member. [Figure 7] FIG. 2 is a perspective view showing the configuration of a center member. [Figure 8] FIG. 1(a) is a cross-sectional view showing the air flow and the state of condensed water in an intake manifold according to an embodiment, and FIG. 1(b) is a cross-sectional view showing the air flow and the state of condensed water in an intake manifold according to a comparative example. [Figure 9] 1 is a graph showing the cumulative displacement amount for each cylinder in each of an example and a comparative example 1. [Figure 10] 1 is a graph showing the overall pressure loss in each of Example and Comparative Examples 1 and 2. [Figure 11] FIG. 10 is a perspective view showing a partial configuration of an intake manifold provided in an intake device of an engine according to a second embodiment. [Figure 12] FIG. 2 is a front view showing the intake manifold with the cover member removed. [Figure 13] FIG. 13 is a cross-sectional view showing the configuration of a cross section taken along line XIII-XIII in FIG. [Figure 14]FIG. 14 is a cross-sectional view showing the configuration of a cross section taken along line XIV-XIV in FIG. [Figure 15] FIG. 2 is a perspective view showing the flow of air in a surge tank of an intake manifold. [Figure 16] FIG. 10 is a top view showing the external configuration of an intake manifold provided in the intake device of the engine according to the third embodiment. [Figure 17] FIG. 10 is a side view showing the external configuration of an intake manifold provided in an intake device for an engine according to a third embodiment. [Figure 18] FIG. 2 is an exploded perspective view showing the configuration of the intake manifold, and ribs and deflection base portions provided on the inner surface of the lower wall of the surge tank. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example of the present invention, and the present invention is not limited to the following embodiment except for its essential configuration.

[0039] [First embodiment] 1. Engine 1 Configuration The configuration of an engine 1 according to the first embodiment will be described with reference to Fig. 1. The engine 1 shown in Fig. 1 is an engine mounted on a vehicle, and some of the configuration is not shown in Fig. 1.

[0040] 1, the engine 1 includes an engine body 2, an intake device 3, an exhaust device 4, a turbocharger 5, an HP-EGR (High Pressure Exhaust Gas Recirculation) unit 8, and an LP-EGR (Low Pressure Exhaust Gas Recirculation) unit 9. The engine body 2 has a plurality of cylinders 2a (for example, four cylinders).

[0041] The intake system 3 has an intake passage 30, an air cleaner 31, an intercooler 32, a throttle valve 33, and an intake manifold 6. The intake passage 30 is connected to the intake manifold 6 via the air cleaner 31, the intercooler 32, the throttle valve 33, and the compressor 51 of the turbocharger 5. As shown by arrow A1, fresh air (air) is taken into the air cleaner 31, pressurized by the compressor 51, cooled by the intercooler 32, and sent from the throttle valve 33 to the intake manifold 6. Note that, in the intake passage 30, the air is located closer to the compressor 51 in the flow direction of the fresh air than the air cleaner 31. Upstream side The portion downstream of the compressor 51 may be referred to as an upstream portion 30a, and the portion downstream of the compressor 51 may be referred to as a downstream portion 30b.

[0042] The intake manifold 6 includes an intake passage 61, a surge tank 62, and a plurality of runners (independent intake passages). 63 The intake air introduction passage 61 has one end connected to the intake passage 30 via the throttle valve 33, and the other end connected to a surge tank 62. 63 Each of the intake manifolds 6 to 66 has one end connected to the surge tank 62 and the other end connected to an intake port formed in the cylinder head of the engine body 2. The detailed structure of the intake manifold 6 will be described later.

[0043] The exhaust system 4 includes an exhaust manifold 7, an exhaust passage 40, and a silencer 41. One end of the exhaust manifold 7 is connected to an exhaust port formed in a cylinder head of the engine body 2, and the other end is connected to the exhaust passage 40. The exhaust passage 40 connects the exhaust manifold 7 and the silencer 41 via a turbine 52 of the turbocharger 5. Exhaust gas discharged from the exhaust port of the engine body 2 applies a rotational driving force to the turbine 52, and then has its pressure and temperature reduced by the silencer 41 before being discharged to the outside (arrow A2). Note that with respect to the exhaust passage 40, the portion upstream of the turbine 52 in the flow direction of the exhaust gas may be referred to as an upstream section 40a, and the portion downstream of the turbine 52 may be referred to as a downstream section 40b.

[0044] The HP-EGR section 8 has an EGR passage 81 and an EGR valve 82. One end of the EGR passage 81 is connected to an exhaust port formed in the cylinder head of the engine body 2, and the other end is connected to the intake air introduction passage 61 of the intake manifold 6. In this embodiment, the other end of the EGR passage 81 is connected to the intake air introduction passage 61 of the intake manifold 6, but it may also be connected to a portion between the intercooler 32 and the throttle valve 33 in the downstream portion 30b of the intake passage 30.

[0045] The EGR valve 82 adjusts the amount of exhaust gas that is recirculated from the exhaust port of the engine body 2 to the intake introduction passage 61 .

[0046] The LP-EGR section 9 has an EGR passage 91, an EGR cooler 92, and an EGR valve 93. The EGR passage 91 is provided to connect the downstream portion 40b of the exhaust passage 40 and the upstream portion 30a of the intake passage 30. The EGR cooler 92 is provided to cool the exhaust gas flowing through the EGR passage 91. The EGR valve 93 adjusts the amount of exhaust gas that is recirculated from the downstream portion 40b of the exhaust passage 40 to the upstream portion 30a of the intake passage 30.

[0047] 2. Configuration of intake manifold 6 The configuration of the intake manifold 6 will be described with reference to FIGS.

[0048] 2 and 3, the intake manifold 6 is formed by joining a base member (first member) 6A, a center member (second member) 6B, and a cover member 6C. In this embodiment, the base member 6A, the center member 6B, and the cover member 6C are each formed from a resin material. Note that the number of members constituting the intake manifold 6, as well as the shapes and materials of each member, can be changed as appropriate.

[0049] The intake air introduction passage 61 is formed by a cylindrical pipe, and has an opening (inlet) 61a at one end to which the throttle valve 33 is connected. As shown in Figures 4 and 5, the other end of the intake air introduction passage 61 is connected to the space in the surge tank 62. The spaces of the intake air introduction passage 61 and the surge tank 62 are separated by a partition wall 61b, except for the portion where the intake air introduction passage 61 and the space in the surge tank 62 are connected.

[0050] 2 to 5, the surge tank 62 is disposed below the portion where the intake air introduction passage 61 is formed. Then, as shown in FIGS. 4 and 5, the partition wall 61b is provided so as to separate the intake air introduction passage 61 and the space of the surge tank 62 in the vertical direction.

[0051] As shown in Fig. 2, the four runners 63 to 66 are each formed to extend in the vertical direction and are arranged in the direction in which the intake air introduction passage 61 extends. As shown in Fig. 3, the upper parts of the runners 63 to 66 are arranged to cover the upper part of the intake air introduction passage 61, and runner outlets 63a, 64a, 65a, and 66a are provided at the ends thereof and connected to intake ports formed in the cylinder head of the engine body 2.

[0052] As shown in Fig. 4, the runners 63 to 66 have openings (runner inlets) 63b, 64b, 65b, and 66b at their lower parts that communicate with the space in the surge tank 62. The runner inlets 63b, 64b, 65b, and 66b of the runners 63 to 66 are provided in a side wall 62j that surrounds the space in the surge tank 62. In this embodiment, the runner inlets 63b, 64b, 65b, and 66b correspond to "openings in a plurality of independent intake passages," and the direction in which the runner inlets 63b, 64b, 65b, and 66b are lined up as shown in Fig. 4 corresponds to "a predetermined direction."

[0053] 2 and 5, each of the runners 63 to 66 has a portion extending upward from the runner inlets 63b, 64b, 65b, and 66b. Also, as shown in FIGS. 4 and 5, the lower end portion of each of the runner inlets 63b, 64b, 65b, and 66b is provided so as to be positioned above the lowest height level of the lower wall inner surface 62a of the surge tank 62.

[0054] As shown in Fig. 4, a rib 62b is formed along the lower wall inner surface 62a from a portion (interval) 62e between the runner inlet 63b and the runner inlet 64b toward the front side of the paper in Fig. 4. Similarly, a rib 62c is formed along the lower wall inner surface 62a from a portion (interval) 62f between the runner inlet 64b and the runner inlet 65b toward the front side of the paper in Fig. 4, and a rib 62d is formed along the lower wall inner surface 62a from a portion (interval) 62g between the runner inlet 65b and the runner inlet 66b toward the front side of the paper in Fig. 4. In this embodiment, the ribs 62b to 62d extending from the lower wall inner surface 62a of The three ribs 62b to 62d have the same height, although it is possible for the heights of the three ribs 62b to 62d to be different from each other.

[0055] 4 and 5, the surge tank 62 has a platform-shaped deflection table 62i formed on the inner surface 62h of a side wall that faces the side wall 62j, on which the runner inlets 63b, 64b, 65b, and 66b are provided, across the space of the surge tank 62. The deflection table 62i is provided so as to cover the entire area facing the runner inlets 63b, 64b, 65b, and 66b in the predetermined direction (the direction perpendicular to the plane of the paper in FIG. 5). The deflection table 62i deflects the air mixed within the space of the surge tank 62 so that it passes above the lowest part of the lower wall inner surface 62h and is guided to the runner inlets 63b, 64b, 65b, and 66b (arrow B). In this embodiment, the deflection table portion 62i is formed so that the protruding height toward the space (toward the side wall 62j) gradually increases from the top to the bottom.

[0056] 3. Formation of surge tank 62 by joining base member 6A and center member 6B As described above, in this embodiment, the intake manifold 6 is configured by joining the base member 6A, the center member 6B, and the cover member 6C, and of these, the base member 6A and the center member 6B form the surge tank 62. The formation of the surge tank 62 by joining the base member 6A and the center member 6B will be described using Figures 6 and 7.

[0057] 6, the base member 6A has a portion that forms part of the intake air introduction passage 61 and a portion that forms part of the surge tank 62. As shown in FIG. 6, when the center member 6B is not joined to the base member 6A, the internal space of the base member 6A is open toward the front side of the page.

[0058] The base member 6A is formed with the entire deflection base portion 62i provided on the sidewall inner surface 62h, base side portions 62b1, 62c1, 62d1 which are parts of the longitudinal directions of the ribs 62b, 62c, 62d, and a base side portion 61b1 which is part of the partition wall 61b which separates the intake air introduction passage 61 from the surge tank 62. The base member 6A including these portions 61b1, 62i, 62b1, 62c1, 62d1 is integrally formed from a resin material.

[0059] 7, the center member 6B has a portion that forms the remaining portion of the intake air introduction passage 61 and a portion that forms the remaining portion of the surge tank 62. As shown in FIG. 7, when the base member 6A is not joined to the center member 6B, the internal space of the center member 6B is also open toward the front side of the page.

[0060] The center member 6B is formed with center-side portions 62b2, 62c2, and 62d2, which are the remaining portions of the ribs 62b, 62c, and 62d in the longitudinal direction, and a center-side portion 61b2, which is the remaining portion of the partition wall 61b that separates the intake air introduction passage 61 and the surge tank 62. These portions 61b2, 62b2, 62c2, and 62d2 are formed by joining the base member 6A and the center member 6B together. , The end faces of 62c1 and 62d1 are joined together.

[0061] The center member 6B has runner inlets 63b, 64b, 65b, and 66b opened in a side wall 62j.

[0062] Similarly, the entire center member 6B, including the center-side portions 61b2, 62b2, 62c2, and 62d2, is integrally formed from a resin material.

[0063] 4. Reduction of the amount of condensed water introduced into the runner inlets 63b, 64b, 65b, and 66b by the deflection base 62i In this embodiment, by providing a deflection base 62i in the surge tank 62 of the intake manifold 6, it is possible to prevent a large amount of condensed water from being suddenly introduced into the runner inlets 63b, 64b, 65b, and 66b due to the air flow. This will be explained using Figures 8 and 9. Note that Figure 8(a) schematically shows the state of air flow and condensed water in an intake manifold 6 according to an example having the same configuration as this embodiment, and Figure 8(b) schematically shows the state of air flow and condensed water in an intake manifold 900 according to Modification 1, in which the surge tank 962 does not have a rib or deflection base.

[0064] 8(a), when the engine body 2 is running, fresh air and EGR gas (hereinafter referred to as "fresh air, etc.") are introduced into the surge tank 62 through the intake air introduction passage. A portion of the fresh air, etc. introduced into the surge tank 62 flows downward along the inner surface 62h of the side wall of the surge tank 62.

[0065] In addition, in the intake manifold 6 according to the embodiment, a partition is provided between the intake air introduction passage and the surge tank 62, so that the fresh air and EGR gas flow while being mixed toward the side of the surge tank 62 where the runner introduction port (#1 runner introduction port) 63b is provided (see FIG. 4, etc.). Here, the runner introduction port 63b is referred to as the #1 runner introduction port 63b, the runner introduction port 64b as the #2 runner introduction port 64b, the runner introduction port 65b as the #3 runner introduction port 65b, and the runner introduction port 66b as the #4 runner introduction port 66b.

[0066] Returning to Figure 8(a), condensed water LQ accumulates between three ribs 62b, 62c, and 62d (only rib 62c is shown in Figure 8(a)) provided on the inner surface 62a of the lower wall of the surge tank 62. The height positions of the tops of the ribs 62b, 62c, and 62d are determined based on the estimated amount of condensed water that will accumulate in the surge tank 62, which is determined at the design stage of the intake manifold 6.

[0067] As described above, the surge tank 62 of the intake manifold 6 is provided with the deflection base portion 62i on the side wall inner surface 62h, so that fresh air flows to pass above the lower wall inner surface 62a (arrow C1), making it difficult to scoop up the condensed water accumulated on the lower wall inner surface 62a. Therefore, the intake manifold 6 according to the embodiment prevents a large amount of condensed water LQ from being sent all at once to the runner inlets 63b, 64b, 65b, and 66b.

[0068] Furthermore, in the intake manifold 6 according to the embodiment, the ribs 62b, 62c, and 62d are provided on the inner surface 62a of the lower wall of the surge tank 62, and the ribs 62b, 62c, and 62d prevent the condensed water LQ from moving toward the side where the #1 runner inlet 63b is provided in association with the flow of fresh air, etc. This also prevents a large amount of condensed water LQ from being introduced all at once from the #1 runner inlet 63b and the #2 runner inlet 64b.

[0069] Therefore, in the intake device 3 of the engine 1 equipped with the intake manifold 6 according to the embodiment, a large amount of condensed water LQ is prevented from being sent to a specific cylinder 2a all at once, and misfire in that cylinder 2a is suppressed.

[0070] 8(b), also in the intake manifold 900 of Comparative Example 1, when the engine body is running, some of the fresh air and other air introduced into the surge tank 962 through the intake air introduction passage flows from above downward along the sidewall inner surface 962h. In the intake manifold 900 of Comparative Example 1, the sidewall inner surface 962h of the surge tank 962 is not provided with a deflection base, so the fresh air and other air flowing along the sidewall inner surface 962h flows toward the lower wall inner surface 962a where the condensed water LQ has accumulated (arrow C2). Therefore, in the intake manifold 900 of Comparative Example 1, a large amount of condensed water LQ accumulated on the lower wall inner surface 962a of the surge tank 962 is scooped up and introduced into the runner inlet 965b (arrow C3).

[0071] Furthermore, in the intake manifold 900 of Comparative Example 1, no ribs are provided on the inner surface 962a of the lower wall of the surge tank 962, and therefore, the condensed water LQ moves toward the side where the #1 runner inlet is provided due to fresh air flowing in the above-mentioned predetermined direction, resulting in uneven distribution of the condensed water LQ inside the surge tank 962. For this reason, a large amount of condensed water LQ is sent from the #1 runner inlet and the #2 runner inlet to the #1 and #2 runners all at once, which is thought to cause misfires in the cylinders to which these runners are connected.

[0072] As shown in Fig. 9, the amount of condensed water LQ introduced into the #1 to #4 runner inlets was investigated in each of the example and comparative example 1. In the graph shown in Fig. 9, the amount of condensed water LQ introduced from the #1 runner inlet in comparative example 1 is expressed as a relative value, with "100" being used.

[0073] 9, in Comparative Example 1, the amount of condensed water LQ introduced from the #1 and #2 runners is greater than the amount of condensed water LQ introduced from the #3 and #4 runner inlets. In particular, the amount of condensed water LQ introduced from the #1 runner inlet, as shown by arrow D2, is more than 10 times the amount of condensed water LQ introduced from the #4 runner inlet.

[0074] 9, in the embodiment, the amount of condensed water LQ introduced from the #1 to #3 runner inlets 63b, 64b, 65b is greater than the amount of condensed water LQ introduced from the #4 runner inlet 88b, but is kept to about 7.6 times the amount of condensed water LQ introduced from the #3 runner inlet 65b and, as shown by arrow D1, the amount of condensed water LQ introduced from the #4 runner inlet 66b. This shows that in the embodiment in which the deflection base 62i is provided on the side wall inner surface 62h of the surge tank 62 and the ribs 62b to 62d are provided on the bottom wall inner surface 62a, it is possible to suppress unevenness in the amount of condensed water LQ introduced into the #1 to #4 runner inlets 63b, 64b, 65b, 66b.

[0075] 5. Pressure loss between the deflection base 62i and the ribs 62b to 62d The effect on pressure loss caused by providing the deflection base 62i and ribs 62b to 62d in the surge tank 62 will be described with reference to Fig. 10. In Fig. 10, Comparative Example 1 and Example are the same as those described with reference to Figs. 8(a) and (b), and Comparative Example 2 is an example in which the deflection base 62i is not provided in the surge tank 62 compared to the Example shown in Fig. 8(a).

[0076] 10, if the pressure loss in Comparative Example 1 is taken as "100," then the pressure loss in the Example was about 93, and the pressure loss in Comparative Example 2 was about 94. From this, as explained using FIG. 8(b), it is considered that in Comparative Example 1, since the surge tank 962 does not have a deflection base portion or ribs, the condensed water LQ accumulated in the surge tank 962 is biased in the above-mentioned predetermined direction, and the condensed water LQ is scooped up by fresh air, etc., resulting in a large pressure loss.

[0077] In Comparative Example 2, since the surge tank has ribs, the condensed water LQ accumulated in the surge tank is less likely to bias in the above-mentioned specified direction, and it is thought that the pressure loss was kept lower than in Comparative Example 1, even though it does not have a deflection base portion.

[0078] In contrast to this, in the embodiment, the surge tank 62 has the deflection base portion 62i and the ribs 62b to 62d, so that the pressure loss is kept low compared to the comparative examples 1 and 2 (arrows E1 and E2).

[0079] Here, the pressure loss in the example is kept lower (arrow F2), albeit slightly, than in the comparative example 2. This is because, in the example, the deflection base 62i is provided at the bottom of the inner surface 62h of the side wall of the surge tank 62, thereby preventing fresh air and the like from hitting the vicinity of the tops of the ribs 62b to 62d and causing pressure loss.

[0080] 6.Effects In the intake device 3 of the engine 1 according to this embodiment, the deflection base 62i is provided on the side wall inner surface 62h of the surge tank 62 in the intake manifold 6, so that the air flow (arrow C1 in FIG. 8(a)) that flows along the side wall inner surface 62h can pass above the lower wall inner surface 62a. As a result, in the intake manifold 6 of the intake device 3, the condensed water LQ that has accumulated on the lower wall inner surface 62a of the surge tank 62 can be prevented from being introduced into the runners 63 to 66 all at once. Therefore, in the engine 1 equipped with the intake device 3, by preventing a large amount of condensed water LQ from being introduced into the cylinder 2a all at once, misfire in the cylinder 2a can be prevented.

[0081] Furthermore, in the intake device 3 of the engine 1 according to this embodiment, a partition wall 61b is provided in the intake manifold 6 between the intake introduction passage 61 and the space of the surge tank 62, so that the passage length of the intake introduction passage 61 can be ensured. However, it is considered that increasing the passage length may make it easier for the condensed water LQ accumulated on the inner surface 62a of the lower wall of the surge tank 62 to be scooped up due to changes in the air flow inside the surge tank 62.

[0082] However, in the intake device 3 of the engine 1 according to this embodiment, the deflection base 62i is provided on the side wall inner surface 62h of the surge tank 62 in the intake manifold 6, so that it is possible to prevent the condensed water LQ accumulated on the lower wall inner surface 62a of the surge tank 62 from being scooped up by the air flow. Therefore, the engine 1 equipped with the intake device 3 is suitable for preventing misfires in the cylinder 2a caused by the condensed water LQ.

[0083] Furthermore, in the intake device 3 of the engine 1 according to this embodiment, in the intake manifold 6, a deflection base portion 62i is provided on the inner surface 62h of the side wall of the surge tank 62, and the protruding height toward the space side gradually increases from top to bottom, thereby ensuring that the air flowing along the inner surface 62h of the side wall (arrow C1 in Figure 8(a)) passes above the inner surface 62a of the lower wall.

[0084] Furthermore, in the intake device 3 of the engine 1, the deflection base portion 62i of the surge tank 62 is provided in the intake manifold 6 in a range opposite to the multiple runner inlets 63b, 64b, 65b, and 66b, thereby preventing a situation in which a large amount of condensed water LQ is introduced into the cylinder 2a in the engine body 2 all at once.

[0085] Furthermore, in the intake device 3 of the engine 1 according to this embodiment, three ribs 62b-62d are provided on the inner surface 62a of the lower wall of the surge tank 62 so as to extend from portions (interval portions) 62e-62g between the four runner inlets 63b, 64b, 65b, and 66b, respectively, and the ribs restrict the movement of the condensed water LQ in the predetermined direction (the direction in which the runner inlets 63b, 64b, 65b, and 66b are aligned). As a result, in the engine 1 equipped with the intake device 3, it is possible to prevent the condensed water LQ accumulated on the inner surface 62a of the lower wall of the surge tank 62 from being biased downstream in the airflow direction, and to prevent a large amount of condensed water LQ from being introduced all at once into the runners 63, 64 having the runner inlets 63b, 64b downstream in the airflow direction in the predetermined direction, thereby preventing misfires in the cylinders 2a to which the runners 63, 64 are connected.

[0086] Furthermore, in the intake device 3 of the engine 1 according to this embodiment, the intake manifold 6 is formed by joining three components 6A to 6C, including the base component 6A and the center component 6B, so that it is possible to easily manufacture an intake manifold 6 with a complex internal structure having a deflection base portion 62i on the inner surface 62h of the side wall of the surge tank 62.

[0087] Furthermore, in the intake device 3 of the engine 1 according to this embodiment, the runner inlets 63b, 64b, 65b, and 66b are each provided to be positioned higher than the inner surface 62a of the lower wall of the surge tank 62, which prevents the condensed water LQ from undesirably flowing from the surge tank 62 into each of the runners 63 to 66 when the engine 1 is stopped, for example. This prevents misfires from occurring in the cylinder 2a when the engine 1 is restarted, for example.

[0088] Furthermore, in the intake device 3 of the engine 1 according to this embodiment, the runners 63 to 66 each have a portion extending upward from the runner inlets 63b, 64b, 65b, and 66b, so that when the engine 1 is stopped, the condensed water LQ remaining in the runners 63 to 66 is returned to the surge tank 62. This is therefore even more suitable for preventing misfires from occurring in the cylinder 2a when the engine 1 is restarted, for example.

[0089] Furthermore, in the intake device 3 of the engine 1 according to this embodiment, the EGR passage 81 is connected to the intake manifold 6, which suppresses an excessive increase in combustion gas temperature, thereby suppressing the generation of nitrogen oxides (NOx) and reducing pumping loss during intake. Meanwhile, moisture contained in the EGR gas condenses, and condensed water LQ generated from the EGR gas accumulates on the inner surface 62a of the lower wall of the surge tank 62. However, by providing the deflection base 62i on the inner surface 62h of the side wall of the surge tank 62 as described above, it is possible to prevent a large amount of condensed water LQ from being scooped up by the air flow and being introduced all at once into the runner inlets 63b, 64b, 65b, and 66b. Therefore, in the engine 1 equipped with the intake device 3, connecting the EGR passage 81 to the intake manifold 6 achieves the above-described effects, while also suppressing misfires in the cylinder 2a caused by the condensed water LQ being introduced.

[0090] As described above, the intake device 3 of the engine 1 according to this embodiment can prevent the condensed water LQ that has accumulated on the inner surface 62a of the lower wall of the surge tank 62 due to the air flow from being sent all at once to the cylinder 2a, thereby preventing misfires in the cylinder 2a.

[0091] [Second embodiment] An intake system for an engine according to the second embodiment will be described with reference to Figures 11 to 15. Note that the intake system for an engine according to this embodiment differs from the first embodiment in that part of the configuration of the intake manifold 106 is different, but other parts are the same as those of the first embodiment, and therefore the following description will mainly focus on the parts of the intake manifold 106 that differ from the first embodiment.

[0092] As shown in Figure 11, in the intake system of the engine according to this embodiment, the intake manifold 106 is formed by joining three members, including a base member (first member) 106A and a center member (second member) 106B. The configurations of the center member 106B and the cover member are the same as those of the center member 6B and the cover member 6C in the first embodiment. In this embodiment, the number of members constituting the intake manifold 106, as well as the shapes and materials of each member, can be changed as appropriate.

[0093] The intake manifold 106 also has an intake air introduction passage 161 having an introduction port 161a at one end, and a surge tank 162 to which four runners are connected. The intake air introduction passage 161 is disposed above the surge tank 162, and a portion of the space between the intake air introduction passage 161 and the surge tank 162 is separated by a partition wall 161b. The intake air introduction passage 161 is connected to the surge tank 162 at the right side of the paper in FIG. 11. In this embodiment, too, the left-right direction on the paper in FIG. 11 corresponds to the "predetermined direction."

[0094] A deflection table portion 162i is provided on an inner side wall surface 162h of the surge tank 162 so that the protruding height from the inner side wall surface 162h toward the space (the front side of the paper in FIG. 11) gradually increases from top to bottom. The shape and formation range of the deflection table portion 162i are basically the same as those of the deflection table portion 62i of the first embodiment.

[0095] Three ribs 162b to 162d are provided on the lower wall inner surface 162a of the surge tank 162. Similar to the ribs 62b to 62d of the first embodiment, each of the three ribs 162b to 162d is formed to extend from a portion between adjacent runner inlets (not shown in FIG. 11) in a direction intersecting both the up-down direction and the predetermined direction (the depth direction of the paper in FIG. 11). Note that, in this embodiment as well, the runner inlets are provided to be positioned higher than the lower wall inner surface 162a of the surge tank 162, and the deflection base portion 162i of the side wall inner surface 162h is provided higher than the tops of the ribs 162b to 162d.

[0096] In the intake manifold 106 of this embodiment, a deflection protrusion 162j is provided on the deflection base portion 162i. The deflection protrusion 162j is provided in the range from the vicinity of the portion where the rib 162d is provided to the vicinity of the portion where the rib 162b is provided in the predetermined direction. As shown in FIG. 12, when the center member 106B is joined to the base member 106A, the deflection protrusion 162j is formed in the range from the portion between the runner inlet 163b and the runner inlet 164b to the runner inlet 166b. As shown in FIGS. 11 and 12, the deflection protrusion 162j has a triangular pyramid shape, and the ridge portion 162k that protrudes most toward the center member 106B is located in the portion opposite the portion where the runner inlet 164b is provided.

[0097] The deflection protrusion 162j is formed such that the inclination on the runner inlet 165b, 166b side of the ridge line 162k in the predetermined direction is gentler than the inclination on the runner inlet 163b side. 13 and 14, the deflection protrusion 162j is formed to have a smoothly curved surface (a surface without steps or the like) such that the radius of curvature of the main surface gradually increases from the side where the runner inlet 166b is provided toward the ridge line 162k in the predetermined direction.

[0098] 15, when the engine body is running, fresh air and EGR gas (hereinafter referred to as "fresh air, etc.") are introduced (arrow F1) into surge tank 162 through intake air introduction passage 161. In this case, since a partition wall 161b is provided to separate a part of the space between intake air introduction passage 161 and surge tank 162, the fresh air and EGR gas are sent to surge tank 162 while being mixed.

[0099] In the space inside the surge tank 162, fresh air and the like sent to the side where the #4 runner inlet 166b is provided (see also FIG. 12) hits the end wall inner surface 162l on the right side of the paper in FIG. 15 and is deflected downward (arrow F2). Then, the fresh air and the like flowing downward along the end wall inner surface 162l and the side wall inner surface 162h of the surge tank 162 passes above the lower wall inner surface 162a by the deflection base portion 162i and is introduced into each of the runner inlets 163b, 164b, 165b, and 166b (arrow F4).

[0100] Furthermore, the fresh air, etc. that flows downward along the end wall inner surface 162l also flows on the deflection table portion 162i toward the end wall inner surface 162m on the left side of the paper surface in Fig. 15 (arrow F3). Then, the fresh air, etc. flowing as shown by arrow F3 is deflected along the deflection protrusion 162j provided on the deflection table portion 162i toward the side where the runner inlets 163b and 164b are provided (see also Fig. 12), and is introduced into the runner inlets 163b and 164b.

[0101] The intake system of the engine according to this embodiment has the same configuration as the first embodiment except for a part of the configuration of the surge tank 162 of the intake manifold 106, and can therefore achieve the same effects as the first embodiment.

[0102] Furthermore, the engine intake device according to this embodiment further includes the deflection protrusion 162j on the deflection base 162i, so that fresh air flowing along the side wall inner surface 162h in the space inside the surge tank 162 can pass above the lower wall inner surface 162a and be reliably guided to each of the runner inlets 163b, 164b, 165b, and 166b. This allows the engine intake device according to this embodiment to further reduce pressure loss.

[0103] [Third embodiment] In the first embodiment, the engine 1 is provided with a four-cylinder engine body 2, but in this embodiment, an engine body with a six-cylinder engine body is used. The configuration of the intake manifold 206 provided in the intake device differs depending on the number of cylinders in the engine body, and this will be explained below. Except for the number of cylinders in the engine body and the configuration of the intake manifold 206, the intake device of the engine according to this embodiment has the same configuration as the intake device 3 of the engine 1 according to the first embodiment.

[0104] 1. External configuration of intake manifold 206 The external configuration of the intake manifold 206 will be described with reference to FIGS.

[0105] 17, the intake manifold 206 according to this embodiment is also configured by joining together a base member (first member) 206A, a center member (second member) 206B, and a cover member 206C. In this embodiment, the base member 206A, the center member 206B, and the cover member 206C are each formed from a resin material. Note that, in this embodiment, as in the first embodiment, the number of members constituting the intake manifold 206 and the shapes and materials of each member can be changed as appropriate.

[0106] 16 and 17, the intake air introduction passage 261 is formed by a cylindrical pipe, and has an opening (inlet) 261a at one end to which a throttle valve is connected. The intake air introduction passage 261 is bent downward in an arc from the end where the inlet 261a is opened. As shown in FIG. 17, the intake air introduction passage 261 is connected to a surge tank 262.

[0107] As shown in Fig. 17, in this embodiment as well, the surge tank 262 is disposed below the intake air introduction passage 261. As shown in Figs. 16 and 17, six Runner (independent intake passage)263-268 each extend upward from a portion communicating with the space of the surge tank 262 and are arranged to cover the upper part of the surge tank 262. As shown in Fig. 16, the intake air introduction passage 261 is arranged to extend vertically between the runners 265 and 266 in the arrangement direction of the runners 263-268. Note that although the runner outlets of the runners 263-268 are not shown in Figs. 16 and 17, they are arranged to open toward the right side of the paper in Fig. 17 (the opposite side to the installation direction of the inlet 261a of the intake air introduction passage 261).

[0108] 2. Internal structure of surge tank 262 The internal structure of the surge tank 262 in the intake manifold 206 will be described with reference to FIG.

[0109] 18, the intake manifold 206 is configured by joining a cover member 206C and a base member 206A together with a center member 206B sandwiched therebetween, as indicated by arrows G1 and G2. The cover member 206C is provided with outer walls of the runners 263-268 and an inlet 261a of the intake air introduction passage 261.

[0110] The center member 206B is provided with a portion of the peripheral wall of the intake air introduction passage 261, a connection port 261b of the intake air introduction passage 261 with the surge tank 262, and runner introduction ports 263b, 264b, 265b, 266b, 267b, and 268b of the runners 263-268 (portions of the runners 263-268 that communicate with the space of the surge tank 262). The connection port 261b of the intake air introduction passage 261 is formed so as to be directed toward the inner surface 262a of the lower wall of the surge tank 262. In other words, the intake air introduction passage 261 is formed so that a center line passing through the center of the connection port 261b intersects with the inner surface 262a of the lower wall of the surge tank 262.

[0111] The base member 206A is provided with a portion of the outer wall, including the lower wall, of the surge tank 262, and runner outlets (openings connected to intake ports in the engine body) 263a, 264a, 265a, 266a, 267a, and 268a of the runners 263 to 268. As shown in the enlarged portion of Figure 18, in the intake manifold 206, two ribs 262b and 262c are provided on the inner surface 262a of the lower wall of the surge tank 262, and a deflection base 262d is provided on the inner surface 262h of the side wall of the surge tank 262.

[0112] Of the two ribs 262b, 262c, rib 262b is formed to extend from a portion between runner inlet 264b and runner inlet 265b in a direction intersecting both the vertical direction and the arrangement direction (predetermined direction) of runner inlets 263b, 264b, 265b, 266b, 267b, and 268b. Similarly, rib 262c is formed to extend from a portion between runner inlet 266b and runner inlet 267b in a direction intersecting both the vertical direction and the predetermined direction.

[0113] The deflection table portion 262d is formed in a region (including a central portion in the predetermined direction) between the portion where the rib 262b is provided and the portion where the rib 262c is provided, so as to cover a portion of the upper surface of the lower wall inner surface 262a. The deflection table portion 262d is provided so as to protrude from a lower portion of the side wall inner surface 262h of the surge tank 262 toward the center member 206B on which the runner inlets 263b, 264b, 265b, 266b, 267b, and 268b are provided. The height position of the protruding end edge of the deflection table portion 262d is higher than the tops of the ribs 262b and 262c provided on the lower wall inner surface 262a. The deflection table portion 262d is formed in a region between the rib 262b and the rib 262c, so that a vertical space exists between the deflection table portion 262d and the lower wall inner surface 262a of the surge tank 262.

[0114] 3. Suppression of air flow in surge tank 262 and introduction of large amounts of condensed water into runners 263-268 18, in the intake manifold 206, fresh air and the like introduced into the surge tank 262 through the intake air introduction passage 261 collides with the upper surface of a deflection table portion 262d formed on the inner surface 262h of the side wall of the surge tank 262. A portion of the fresh air and the like that collides with the upper surface of the deflection table portion 262d is sent from runner inlets 265b and 266b toward the runners 265 and 266 (arrow G3), another portion is sent from runner inlets 267b and 268b toward the runners 267 and 268 (arrow G4), and the remaining portion is sent from runner inlets 263b and 264b toward the runners 263 and 264 (arrow G5).

[0115] In the intake manifold 206, a deflection base 262e is provided on the inner side wall 262h of the surge tank 262, thereby preventing fresh air, etc. introduced into the surge tank 261 through the intake air introduction passage 261, from directly hitting the condensed water accumulated in the region 262e. As a result, the condensed water accumulated in the region 262e is less likely to be scooped up by the flow of fresh air, etc., and a large amount of condensed water is sent from the runner inlet ports 265b, 266b to the runners 265, 266, preventing misfires in the cylinders to which these runners 265, 266 are connected.

[0116] Furthermore, in this embodiment, two ribs 262b, 262c are provided on the inner surface 262a of the lower wall of the surge tank 262 of the intake manifold 206. This limits the movement of condensed water from the region 262e between the ribs 262b, 262c to the regions 262f, 262g on both sides of the region where the ribs 262b, 262c are provided in the predetermined direction due to the influence of the flow of fresh air, etc. Therefore, in this embodiment, uneven distribution of condensed water in the surge tank 262 of the intake manifold 206 is suppressed, and a large amount of condensed water is prevented from being sent to a specific cylinder all at once. Therefore, as in the first embodiment, misfires in specific cylinders can be suppressed.

[0117] In addition, although the intake device of the engine according to this embodiment differs from the first embodiment in part of the configuration of the intake manifold 206, the remaining configuration is the same as that of the first embodiment, and therefore the same effects as those of the first embodiment can be obtained.

[0118] [Variations] In the first and second embodiments, the intake manifold 6, 106 is provided with a partition wall 61b, 161b that separates a portion of the space between the intake introduction passage 61, 161 and the surge tank 62, 162, but in the present invention, it is not necessarily necessary to provide a partition wall.

[0119] In the first and second embodiments, three ribs 62b-62d and 162b-162d are provided on the inner surface 62a of the lower wall of the surge tank 62, 162 in the intake manifold 6, 106, respectively, but in the present invention, the same effect as above can be obtained by providing at least one rib. Note that in the present invention, it is not necessary to provide a rib on the inner surface of the lower wall of the surge tank.

[0120] In addition, in the third embodiment described above, two ribs 262b, 262c are provided on the inner surface 262a of the lower wall of the surge tank 262 in the intake manifold 206, but in the present invention, three or more ribs may be provided, or no ribs may be provided.

[0121] In the first and second embodiments, the surge tank 62, 162 of the intake manifold 6, 106 is provided with a deflection base portion 62i, 162i on the inner surface 62h, 162h of the side wall over the entire area in the specified direction, but in the present invention, the deflection base portion may be provided in at least a partial area in the specified direction.

[0122] In addition, in the third embodiment, the deflection table portion 262h is provided on the side wall inner surface 262h of the surge tank 262 of the intake manifold 206 in a partial area in the predetermined direction, but in the present invention, the deflection table portion may be provided over the entire area in the predetermined direction.

[0123] Furthermore, in the second embodiment, the deflection protrusion 162j is provided on the deflection table 162i, but a similar deflection protrusion may be provided on the deflection table 262d of the third embodiment.

[0124] In the first, second, and third embodiments, the runner inlets 63b, 64b, 65b, 66b, 163b, 164b, 165b, 166b, 263b, 264b, 266b, 267b, and 268b in the intake manifolds 6, 106, and 206 are positioned higher than the inner lower wall surfaces 62a, 162a, and 262a of the surge tanks 62, 162, and 262, respectively. However, in the present invention, the runner inlets may be positioned at the same height as the inner lower wall surface of the surge tank or at a lower position than the inner lower wall surface of the surge tank.

[0125] Furthermore, in the first, second, and third embodiments, EGR gas is recirculated to the intake manifold 6, 106, 206 together with fresh air, but in the present invention, the recirculation of EGR gas to the intake manifold is not essential.

[0126] Furthermore, in the first, second, and third embodiments, the intake manifolds 6, 106, and 206 are formed by combining three members 6A, 6B, 6C, 106A, 106B, 106C, 206A, 206B, and 206C, but in the present invention, the intake manifold may be formed by combining two members, or may be formed by combining four or more members.

[0127] Furthermore, in the first embodiment, the second embodiment, and the third embodiment, an engine equipped with a turbocharger is used as an example, but a turbocharger is not an essential component of the present invention.

[0128] Furthermore, in the first and second embodiments, a four-cylinder engine was used as an example of the engine body 2, and in the third embodiment, a six-cylinder engine was used as an example of the engine body, but the present invention can also use an engine with three or fewer cylinders, five cylinders, or seven or more cylinders. [Explanation of symbols]

[0129] 1 engine 3. Intake system 6,106,206 Intake manifold 6A, 106A, 206A Base member (first member) 6B, 106B, 206B Center member (second member) 6C, 106C Cover member 61,161,261 Intake passage 61b,161b Bulkhead 62,162,262 surge tank 62a, 162a, 262a Inner surface of lower wall 62b,62c,62d,162b,162c,162d,262b,262c Ribs 62h, 162h, 262h Inner surface of side wall (inner surface of opposing side wall) 62i,162i,262d Deflection table part 63~66, 263~268 Runner (Independent Intake Passage) 162j Deflection convex part

Claims

1. An intake system for an engine, comprising: an engine body having a plurality of cylinders and a cylinder head in which intake ports connected to each of the plurality of cylinders are formed; an intake manifold through which air passes to the plurality of intake ports in the engine body; Equipped with The intake manifold is a plurality of independent intake passages arranged along a cylinder row direction in the engine body and connected to the plurality of intake ports, respectively; a surge tank having a space where the plurality of independent intake passages are gathered, and arranged so that openings of the plurality of independent intake passages are aligned in a predetermined direction; an intake air introduction passage that is formed to extend from one end side to the other end side of the surge tank along the predetermined direction, and that is connected to the space in the surge tank at the other end side, and that introduces air into the surge tank; and the intake air introduction passage and the space in the surge tank are separated by a partition wall except for a communicating portion at the other end, the surge tank has a deflection base portion provided on an inner surface of a side wall that faces the side wall in which the plurality of openings are provided, with the space therebetween; The deflection base portion is provided so as to protrude from the inner surface of the opposing side wall toward the plurality of openings in a range facing the plurality of openings in the predetermined direction, and is provided so that the protrusion height toward the space side gradually increases from top to bottom, and deflects the flow of air flowing along the inner surface of the side wall so that it passes above the inner surface of the lower wall of the surge tank and flows toward at least some of the plurality of openings. Engine intake system.

2. In the intake device of the engine described in claim 1, The surge tank further includes a deflection protrusion provided on the deflection base portion and configured to deflect the air flow flowing through the space of the surge tank from the other end side to the one end side toward the plurality of openings. Engine intake system.

3. An intake device for an engine, comprising: an engine body having a plurality of cylinders and a cylinder head in which intake ports connected to each of the plurality of cylinders are formed; an intake manifold through which air passes to the plurality of intake ports in the engine body; Equipped with The intake manifold is a plurality of independent intake passages arranged along a cylinder row direction in the engine body and connected to the plurality of intake ports, respectively; a surge tank having a space where the plurality of independent intake passages are gathered, and arranged so that openings of the plurality of independent intake passages are aligned in a predetermined direction; an intake air introduction passage that is formed to extend from one end side to the other end side of the surge tank along the predetermined direction, and that is connected to the space in the surge tank at the other end side, and that introduces air into the surge tank; and the intake air introduction passage and the space in the surge tank are separated by a partition wall except for a communicating portion at the other end, the surge tank has a deflection table portion provided on the inner surface of the side wall that faces the side wall in which the plurality of openings are provided, with the space therebetween, and a deflection protrusion portion that is provided on the deflection table portion and deflects the flow of air that flows through the space of the surge tank from the other end side to the one end side toward the plurality of openings, The deflection base deflects the air flowing along the inner surface of the side wall so that the air flows above the inner surface of the lower wall of the surge tank and toward at least some of the plurality of openings. Engine intake system.

4. The engine intake system according to any one of claims 1 to 3, The surge tank further includes a plurality of ribs provided on the inner surface of the bottom wall of the surge tank so as to extend from each of the portions between the adjacent openings toward the inner surface of the opposing side wall. Engine intake system.

5. An intake device for an engine, comprising: an engine body having a plurality of cylinders and a cylinder head in which intake ports connected to each of the plurality of cylinders are formed; an intake manifold through which air passes to the plurality of intake ports in the engine body; Equipped with The intake manifold is a plurality of independent intake passages arranged along a cylinder row direction in the engine body and connected to the plurality of intake ports, respectively; a surge tank having a space where the plurality of independent intake passages are gathered, and arranged so that openings of the plurality of independent intake passages are aligned in a predetermined direction; an intake air introduction passage that is connected to the space in the surge tank at a central portion in the predetermined direction so as to be directed toward an inner surface of a lower wall of the surge tank at a portion that is connected to the space in the surge tank, and that introduces air into the surge tank; and the surge tank has a deflection table provided on the inner surface of a side wall that faces the side wall having the plurality of openings therein with the space therebetween, and two ribs that are provided on the inner surface of the lower wall at portions on both sides of the deflection table in the predetermined direction, each rib extending from a portion between adjacent openings toward the inner surface of the opposing side wall, the deflection table portion is provided in a region including a central portion in the predetermined direction so as to protrude from the inner surface of the opposing side wall toward some of the plurality of openings so as to cover an upper portion of the inner surface of the lower wall, and deflects the air flow flowing along the inner surface of the side wall so as to pass above the inner surface of the lower wall and flow toward at least some of the plurality of openings. Engine intake system.

6. The engine intake device according to any one of claims 1 to 5, The intake manifold is configured by joining a plurality of members including a first member and a second member that define the space of the surge tank by joining the inner surface of the side wall on which the plurality of openings are provided and the inner surface of the side wall on which the deflection base portion is provided in such a direction that they face each other. Engine intake system.

7. The engine intake device according to any one of claims 1 to 6, The plurality of openings are provided so that their lower end portions are positioned above the inner surface of the lower wall of the surge tank. Engine intake system.

8. The engine intake device according to any one of claims 1 to 7, Each of the plurality of independent intake passages has a portion extending upward from the opening. Engine intake system.

9. The engine intake system according to any one of claims 1 to 8, An EGR passage for introducing EGR gas is connected to the intake manifold. Engine intake system.

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