Intake system for internal combustion engine

Abstract

To provide an intake device for an internal combustion engine, which can suppress a pressure loss.SOLUTION: An intake device for an internal combustion engine, comprises an intake passage for introducing air into the internal combustion engine, a throttle valve provided in the intake passage, and an EGR passage connected to the intake passage and an exhaust passage of the internal combustion engine. The EGR passage is connected downstream of the throttle valve in the intake passage, and an end of the EGR passage protrudes inward of the intake passage from an inner wall of the intake passage, and is opposed to the axis of the throttle valve along a direction in which air in the intake passage flows.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] 2. Description of the Related Art Exhaust gas recirculation (EGR) devices that recirculate exhaust gas from an internal combustion engine to an intake passage are known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-210848 A Summary of the Invention [Problem to be solved by the invention]

[0004] By protruding the EGR passage into the inside of the intake passage, the EGR gas can be effectively diffused into the air in the intake passage. However, there is a risk of the air colliding with the EGR passage increasing the pressure loss. Therefore, the object of the present invention is to provide an intake device for an internal combustion engine that can achieve both the distribution of EGR gas and the suppression of pressure loss. [Means for solving the problem]

[0005] The above object is to provide an internal combustion engine having an intake passage for introducing air into the internal combustion engine, a throttle valve provided in the intake passage, and an EGR passage connected to the intake passage and an exhaust passage of the internal combustion engine, the intake passage includes a first intake passage and a plurality of second intake passages, the first intake passage extends in a first direction, the plurality of second intake passages are connected to a downstream side of the first intake passage and are connected to a plurality of cylinders of an internal combustion engine, the plurality of second intake passages are arranged on both sides of the first intake passage in a second direction intersecting the first direction, and the throttle valve is provided in the first intake passage, The EGR passage is No. 1 The EGR passage is connected to the intake passage downstream of the throttle valve, and an end of the EGR passage is No. 1 The inner wall of the intake passage No. 1 protruding into the inside of the intake passage, In the first direction This can be achieved by an intake system of the internal combustion engine that faces the axis of the throttle valve.

[0006] The central axis of the EGR passage is First Direction may overlap the axis of the throttle valve along

[0007] The intake passage may have a surge tank, the surge tank having a width greater than that of the first intake passage in the second direction, the first intake passage being connected to an upstream side of the surge tank, and the plurality of second intake passages being connected to a downstream side of the surge tank. .

[0008] A catalyst for purifying exhaust gas may be provided in the exhaust passage, and the EGR passage may be connected to the exhaust passage upstream of the catalyst. Effect of the Invention

[0009] It is possible to provide an intake device for an internal combustion engine that is capable of suppressing pressure loss. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating an engine system. [Diagram 2] Fig. 2(a) is a cross-sectional view illustrating an intake system, and Fig. 2(b) is a plan view of a throttle valve and an EGR passage. [Diagram 3] FIG. 3 is a front view illustrating the intake device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an intake device of an internal combustion engine according to the present embodiment will be described with reference to the drawings. Fig. 1 is a schematic diagram illustrating an engine system 100. The engine system 100 has an internal combustion engine 10 (engine), an intake device 11, a supercharger 30, and an EGR device 40. The internal combustion engine 10 is, for example, a gasoline engine or a diesel engine. The internal combustion engine 10 is a four-cylinder engine and has four cylinders 10a, 10b, 10c, and 10d.

[0012] The intake system 11 has an intake passage 12, a throttle valve 26, and an EGR system 40. The intake passage 12 has an intake passage 13 (first intake passage), intake passages 15a, 15b, 15c, and 15d, and a surge tank 16. The intake passage 13 is provided with an air cleaner 20, an air flow meter 22, a compressor 32 of a turbocharger 30, an intercooler 24, and a throttle valve 26, in this order from the upstream side. The intake passage 13 is located upstream of the surge tank 16 and connected to the surge tank 16. The four intake passages 15a, 15b, 15c, and 15d (second intake passages) are located downstream of the surge tank 16 and connected to the surge tank 16.

[0013] The exhaust passage 18 branches into four on the upstream side and merges into one passage on the downstream side. The turbocharger 30 has a compressor 32 and a turbine 34. The EGR device 40 has an EGR passage 42, an EGR catalyst 44, an EGR cooler 46, and an EGR valve 48. The exhaust passage 18 is provided with, in order from the upstream side, the turbine 34 of the turbocharger 30 and a catalyst 28. The catalyst 28 includes a start-up catalyst (S / C, start-up converter), an SCR (Selective Catalytic Reduction) catalyst, and an NOx Storage-Reduction (NSR) catalyst, and purifies the exhaust gas.

[0014] Four cylinders 10a, 10b, 10c and 10d of the internal combustion engine 10 are connected to four intake passages 15a, 15b, 15c and 15d, and an exhaust passage 18 branched into four.

[0015] Air flows in this order through the intake passage 12, the surge tank 16, and the four intake passages 15a, 15b, 15c, and 15d. The air cleaner 20 purifies the air. The air flow meter 22 detects the amount of air. The throttle valve 26 adjusts the flow rate of air. The larger the opening of the throttle valve 26, the larger the flow rate of air. The smaller the opening of the throttle valve 26, the smaller the flow rate of air.

[0016] Air is distributed to four intake passages 15a, 15b, 15c, and 15d and introduced into the four cylinders of the internal combustion engine 10. A mixture of air and fuel is burned in the internal combustion engine 10. Exhaust gas generated by the combustion is discharged into the exhaust passage 18, purified by the catalyst 28, and discharged outside the vehicle.

[0017] The turbine 34 rotates when the exhaust air is blown against it. The compressor 32 is connected to the turbine 34 and rotates together with the turbine 34. The air is supercharged when the compressor 32 rotates. The intercooler 24 cools the supercharged air. By introducing high-pressure air into the internal combustion engine 10, the output of the internal combustion engine 10 can be improved.

[0018] A part of the exhaust gas (EGR gas) is recirculated to the intake passage 12 by the EGR device 40 and introduced into the internal combustion engine 10 for combustion. By mixing the EGR gas with the air, the oxygen concentration decreases. The combustion temperature decreases, so the generation of nitrogen oxides (NOx) can be suppressed.

[0019] The EGR device 40 is a HPL (High Pressure Loop)-EGR device. One end of the EGR passage 42 is connected to the intake passage 12 downstream of the compressor 32 and the throttle valve 26 and upstream of the surge tank 16. The other end of the EGR passage 42 is connected to the exhaust passage 18 downstream of the joining position of the branched passages and upstream of the turbine 34 and the catalyst 28.

[0020] In the EGR passage 42, an EGR catalyst 44, an EGR cooler 46, and an EGR valve 48 are provided in this order from the side closer to the exhaust passage 18 toward the intake passage 12. The EGR catalyst 44 purifies the EGR gas. The EGR cooler 46 cools the EGR gas. The EGR valve 48 controls the flow rate of the EGR gas. The larger the opening of the EGR valve 48, the larger the flow rate of the EGR gas. The smaller the opening of the EGR valve 48, the smaller the flow rate of the EGR gas.

[0021] 2(a) is a cross-sectional view illustrating the intake system 11, illustrating a plane parallel to the axis 26a of the throttle valve 26. The throttle valve 26 is a butterfly valve, and has a shaft 26a and a valve body 26b. The shaft 26a crosses the intake passage 13. The throttle valve 26 opens and closes as the valve body 26b rotates about the shaft 26a as a rotation axis. Air flows through the intake passage 13 in the direction of the arrow. The inner wall 13a is the inner wall surface of the intake passage 13.

[0022] The EGR passage 42 is spaced from the throttle valve 26 along the air flow direction, is aligned with and faces the axis 26a of the throttle valve 26. The EGR passage 42 is located downstream of the throttle valve 26 and protrudes into the intake passage 13. An end 42a of the EGR passage 42 is located further inside the intake passage 13 than the inner wall 13a, and faces the axis 26a.

[0023] FIG. 2(b) is a plan view of the throttle valve 26 and the EGR passage 42, as viewed from the upstream side of the intake passage 13. Air flows from the back to the front side of FIG. 2(b). The EGR passage 42 is a cylindrical pipe that protrudes linearly into the inside of the intake passage 13. Line L1 is an imaginary line segment indicating the central axis of the EGR passage 42, which extends along the extension direction of the EGR passage 42 and passes through the center of the EGR passage 42. Line L1 extends in the same direction as the axis 26a of the throttle valve 26. That is, the central axis of the EGR passage 42 extends in the same direction as the axis 26a of the throttle valve 26, and overlaps with the axis 26a in the air flow direction.

[0024] Fig. 3 is a front view illustrating the intake device 11. In Fig. 3, the flow of air is indicated by arrows. The air flows along the extension direction of the intake passage 13. The EGR passage 42 is located downstream of the axis 26a of the throttle valve 26. The central axis (line L1) of the EGR passage 42 is aligned with the axis 26a of the throttle valve 26 in the air flow direction. The central axis of the EGR passage 42, the axis 26a of the throttle valve 26, and the intake passage 13 are parallel to one another.

[0025] 3, air is introduced into the intake passage 13, collides with the shaft 26a of the throttle valve 26, and is divided by the shaft 26a. The divided air flows so as to avoid the EGR passage 42, is distributed to the four intake passages 15a, 15b, 15c, and 15d, and is introduced into the four cylinders of the internal combustion engine 10.

[0026] According to this embodiment, the EGR passage 42 is connected downstream of the throttle valve 26 of the intake passage 13 and protrudes inward from the inner wall 13a of the intake passage 13. Compared to a case where the end 42a of the EGR passage 42 is located on the inner wall 13a, the EGR passage 42 protrudes, so that the EGR gas is effectively diffused into the air of the intake passage 13, improving the distribution of the EGR gas. The end 42a of the EGR passage 42 faces the shaft 26a of the throttle valve 26. The air is divided by the shaft 26a of the throttle valve 26 and flows so as to avoid the EGR passage 42. Therefore, pressure loss caused by the air colliding with the EGR passage 42 is suppressed. It is possible to achieve both distribution of the EGR gas and suppression of pressure loss. By suppressing pressure loss, a decrease in the output of the internal combustion engine 10 is suppressed.

[0027] It is more preferable that the central axis of the EGR passage 42 overlaps with the axis 26a of the throttle valve 26 along the air flow direction. Air that collides with the axis 26a flows so as to avoid the EGR passage 42, and is less likely to collide with the EGR passage 42. Pressure loss is effectively suppressed.

[0028] The intake passage 12 has one intake passage 13 and four intake passages 15a, 15b, 15c, and 15d. The four intake passages 15a, 15b, 15c, and 15d are located downstream of the intake passage 13, branch off from the intake passage 13, and are connected to the cylinders 10a, 10b, 10c, and 10d of the internal combustion engine 10. The EGR gas flows into the intake passages 15a, 15b, 15c, and 15d together with air, and is distributed to the four cylinders of the internal combustion engine 10. By protruding the EGR passage 42, the EGR gas can be distributed more evenly to the four cylinders 10a, 10b, 10c, and 10d, compared to a case in which the EGR passage 42 does not protrude.

[0029] The EGR passage 42 may be branched into four passages corresponding to the intake passages 15a, 15b, 15c, and 15d, and the branched passages may be connected to the four intake passages 15a, 15b, 15c, and 15d. The EGR gas can be distributed evenly to the four cylinders 10a, 10b, 10c, and 10d. However, the branched EGR passages become narrower and may be clogged due to deposits. In this embodiment, one EGR passage 42 is connected to the intake passage 13. The EGR passage 42 is wider than the branched passages. The cross-sectional area of ​​the EGR passage 42 is increased, thereby suppressing clogging due to deposits. The number of the branched intake passages is equal to the number of cylinders of the internal combustion engine 10. The number of cylinders may be four or less, or may be four or more.

[0030] The EGR passage 42 is connected to the exhaust passage 18 upstream of the catalyst 28. Since the exhaust gas before being purified by the catalyst 28 is recirculated through the EGR passage 42, deposits are likely to occur. Since one wide EGR passage 42 is connected to the exhaust passage 18 and the intake passage 13, the EGR passage 42 is less likely to be clogged by deposits. The EGR passage 42 may be cylindrical, elliptical cylindrical, or the like.

[0031] Although a preferred embodiment of the present invention has been described in detail above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0032] 10 Internal combustion engine 10a, 10b, 10c, 10d cylinders 11. Intake system 12, 13, 15a, 15b, 15c, 15d Intake passage 13a Inner wall 16 Surge Tank 18 Exhaust passage 20 Air cleaner 22 Air flow meter 24 Intercooler 26 Throttle valve 26a axis 26b Valve body 28 Catalyst 30 Turbocharger 32 Compressor 34 Turbine 40 EGR device 42 EGR passage 42a end 44 EGR catalyst 46 EGR cooler 48 EGR valve 100 Engine System

Claims

1. an intake passage for introducing air into the internal combustion engine; a throttle valve provided in the intake passage; an EGR passage connected to the intake passage and an exhaust passage of the internal combustion engine, The intake passage includes a first intake passage and a plurality of second intake passages, The first intake passage extends in a first direction, the second intake passages are connected to a downstream side of the first intake passage and are connected to a plurality of cylinders of an internal combustion engine; the second intake passages are arranged on both sides of the first intake passage in a second direction intersecting the first direction, the throttle valve is provided in the first intake passage, the EGR passage is connected to the first intake passage downstream of the throttle valve, an end of the EGR passage protrudes further inwardly of the first intake passage than an inner wall of the first intake passage and faces an axis of the throttle valve in the first direction;

2. 2. The intake system for an internal combustion engine according to claim 1, wherein a central axis of the EGR passage overlaps with an axis of the throttle valve along the first direction.

3. The intake passage has a surge tank, the surge tank has a width greater than that of the first intake passage in the second direction, the first intake passage is connected to the upstream side of the surge tank, 3. The intake system for an internal combustion engine according to claim 1, wherein the second intake passages are connected to a downstream side of the surge tank.

4. A catalyst for purifying exhaust gas is provided in the exhaust passage, 4. The intake system for an internal combustion engine according to claim 1, wherein the EGR passage is connected to a portion of the exhaust passage upstream of the catalyst.

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