阅读说明：本技术 混合连接器以及发动机 (Hybrid connector and engine ) 是由 神山知大 小田智德 三木章弘 于 2019-08-07 设计创作，主要内容包括：混合连接器(100)具备：进气通路(101)；EGR通路(103),其使从发动机主体排出的排出气体的一部分作为EGR气体返回到进气通路；合流部(104),其以进气通路以及EGR通路的长度方向相互交叉的方式将EGR通路连接于进气通路。构成进气通路的内表面并位于与合流部相反的一侧的相反壁面(115)中的、位于比合流部更靠进气通路的导入口(101A)侧的位置的上游侧区域(116)包含：从合流部侧向导入口按顺序隔开间隔地配置的第一壁面(116A)以及第二壁面(116B)；在第一壁面以及第二壁面之间相对于第一壁面向内侧突出的第三壁面(116C)。(A hybrid connector (100) is provided with: an intake passage (101); an EGR passage (103) for returning a part of exhaust gas discharged from the engine body to the intake passage as EGR gas; and a junction (104) that connects the EGR passage to the intake passage so that the longitudinal directions of the intake passage and the EGR passage intersect with each other. An upstream region (116) of an opposite wall surface (115) that forms an inner surface of the intake passage and is located on the opposite side of the merging portion, the upstream region being located closer to an inlet (101A) of the intake passage than the merging portion, the upstream region including: a first wall surface (116A) and a second wall surface (116B) which are arranged in order from the merging section side to the introduction opening at intervals; and a third wall surface (116C) protruding inward with respect to the first wall surface between the first wall surface and the second wall surface.)

1. A hybrid connector is provided with:

an intake passage for introducing outside air into the engine main body;

an EGR passage that takes out a part of exhaust gas discharged from the engine body as EGR gas and returns the EGR gas to the intake passage;

a merging section that connects the EGR passage to a middle portion in a longitudinal direction of the intake passage so that longitudinal directions of the intake passage and the EGR passage intersect with each other;

an upstream region, which constitutes an inner surface of the intake passage and is located on an opposite wall surface on an opposite side to the merging portion in a direction orthogonal to a longitudinal direction of the intake passage, at a position closer to a gas introduction port side of the intake passage than the merging portion includes:

a first wall surface and a second wall surface that are arranged in order from the merging portion side to the introduction port at intervals in a longitudinal direction of the intake passage;

a third wall surface protruding inward with respect to the first wall surface between the first wall surface and the second wall surface.

2. The hybrid connector of claim 1,

the third wall surface is an inclined surface inclined so as to extend toward the introduction port as extending from an end of the first wall surface on the introduction port side toward an inner side of the first wall surface,

the first wall surface is continuous with the third wall surface in a curved surface, and the second wall surface is continuous with the third wall surface in a curved surface.

3. The hybrid connector of claim 1 or 2,

the intake passage has:

an upstream passage including the inlet;

a downstream passage located on a downstream end side of the upstream passage and extending in a direction different from the upstream passage;

a curved passage connecting the upstream passage and the downstream passage;

the merging portion is located at least at an upstream end portion of the downstream side passage located on the curved passage side,

the hybrid connector includes a convex portion that protrudes from an inner region of the inner surface of the downstream-side passage that corresponds to a radially inner side of the curved passage, is located between the joining portion and an opposing region that is a region of the opposite wall surface that opposes the joining portion, and opposes the joining portion,

a gap is formed between a front end of the projection in the projection direction and an outer region of the inner surface of the downstream side passage that faces the inner region.

4. The hybrid connector of claim 3,

the upstream end of the projection is inclined from the upstream passage to the downstream passage as it goes from the base end to the tip end in the projection direction of the projection.

5. The hybrid connector of any one of claims 1 to 4,

in an opposing region of the opposing wall surface that opposes the joining portion, a recessed portion recessed from the opposing wall surface is formed.

6. A hybrid connector is provided with:

an intake passage for introducing outside air into the engine main body;

an EGR passage that takes out a part of exhaust gas discharged from the engine body as EGR gas and returns the EGR gas to the intake passage;

a merging section that connects the EGR passage to a middle portion in a longitudinal direction of the intake passage so that longitudinal directions of the intake passage and the EGR passage intersect with each other;

the intake passage has:

an upstream passage including an inlet of the intake passage;

a downstream passage located on a downstream end side of the upstream passage and extending in a direction different from the upstream passage;

a curved passage connecting the upstream passage and the downstream passage;

the merging portion is located at least at an upstream end portion of the downstream side passage located on the curved passage side,

the hybrid connector includes a convex portion that protrudes from an inner region of the inner surface of the downstream passage, the inner region corresponding to a radially inner side of the curved passage, is located between the joining portion and an opposing region, and opposes the joining portion, the opposing region being located on an opposite side from the joining portion in a direction orthogonal to a longitudinal direction of the intake passage and opposing the joining portion,

a gap is formed between a front end of the projection in the projection direction and an outer region of the inner surface of the downstream side passage that faces the inner region.

7. An engine provided with the hybrid connector according to any one of claims 1 to 6 and an engine main body.

Technical Field

The invention relates to a hybrid connector and an engine.

Background

Patent documents 1 to 3 disclose the following engines: in order to reduce NOx in the exhaust gas discharged from the engine body, a part of the exhaust gas discharged from the engine body is mixed with outside air (fresh air) as EGR gas (exhaust recirculation gas) and returned to the engine body. In the engines of patent documents 1 to 3, a heater for heating the outside air is provided in an intake passage for introducing the outside air into the engine body at a position upstream of a merging portion where the outside air merges with the EGR gas.

Documents of the prior art

Patent document

Patent document 1: U.S. patent application publication No. 2012/0180478 specification

Patent document 2: japanese patent laid-open publication No. 2018-188983

Patent document 3: japanese patent laid-open publication No. 2010-144669

Disclosure of Invention

Technical problem to be solved by the invention

However, in such an engine, the EGR gas may flow back to a position upstream of the intake passage from the merging portion. In this case, there is a problem that soot contained in the EGR gas adheres to the heater, thereby degrading the performance of the heater.

Note that the reverse flow of the EGR gas in the intake passage is caused due to: in an engine in operation, all intake valves of the engine main body are momentarily or temporarily closed, so that the flow of outside air flowing from the intake passage to the engine main body is temporarily stopped.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a hybrid connector and an engine that can suppress a decrease in the performance of a heater by suppressing the EGR gas from reaching the heater.

Means for solving the problems

A hybrid connector according to a first aspect of the present invention includes: an intake passage for introducing outside air into the engine main body; an EGR passage that takes out a part of exhaust gas discharged from the engine body as EGR gas and returns the EGR gas to the intake passage; a merging section that connects the EGR passage to a middle portion in a longitudinal direction of the intake passage so that longitudinal directions of the intake passage and the EGR passage intersect with each other; an upstream region, which constitutes an inner surface of the intake passage and is located on an opposite wall surface on an opposite side to the merging portion in a direction orthogonal to a longitudinal direction of the intake passage, at a position closer to a gas introduction port side of the intake passage than the merging portion includes: a first wall surface and a second wall surface that are arranged in order from the merging portion side to the introduction port at intervals in a longitudinal direction of the intake passage; a third wall surface protruding inward with respect to the first wall surface between the first wall surface and the second wall surface.

A hybrid connector according to a second aspect of the present invention includes: an intake passage for introducing outside air into the engine main body; an EGR passage that takes out a part of exhaust gas discharged from the engine body as EGR gas and returns the EGR gas to the intake passage; a merging section that connects the EGR passage to a middle portion in a longitudinal direction of the intake passage so that longitudinal directions of the intake passage and the EGR passage intersect with each other; the intake passage has: an upstream passage including an inlet of the intake passage; a downstream passage located on a downstream end side of the upstream passage and extending in a direction different from the upstream passage; a curved passage connecting the upstream passage and the downstream passage; the merging portion is located at least at an upstream end portion of the downstream side passage on the curved passage side, the mixing connector includes a convex portion that protrudes from an inner region corresponding to a radially inner side of the curved passage in an inner surface of the downstream side passage, is located between the merging portion and an opposing region, and opposes the merging portion, the opposing region is located on an opposite side of the merging portion in a direction orthogonal to a longitudinal direction of the intake passage and opposes the merging portion, and a gap is formed between a tip in a protruding direction of the convex portion and an outer region opposing the inner region in the inner surface of the downstream side passage.

An engine according to a first aspect of the present invention includes the hybrid connector and an engine main body.

Effects of the invention

According to the present invention, it is possible to suppress the EGR gas from reaching the heater provided at the inlet port of the intake passage and to suppress the performance of the heater from being degraded.

Drawings

Fig. 1 is a schematic diagram showing an engine according to an embodiment of the present invention.

Fig. 2 is a perspective view showing an external appearance of a hybrid connector according to an embodiment of the present invention.

Fig. 3 is a perspective view showing an intake passage and an EGR passage inside the hybrid connector of fig. 2.

Fig. 4 is a sectional view IV-IV of fig. 2.

Fig. 5 is a V-V sectional view of fig. 4.

Fig. 6 is a cross-sectional view VI-VI of fig. 4.

FIG. 7 is a sectional view VII-VII of FIGS. 4-6.

FIG. 8 is a sectional view VIII-VIII of FIGS. 5-7.

Detailed Description

Hereinafter, an embodiment of the present invention will be described in detail with reference to fig. 1 to 8. The hybrid connector 100 of the present embodiment is provided in the engine 1 illustrated in fig. 1. First, the engine 1 will be explained.

< Engine >

As shown in fig. 1, the engine 1 includes an engine main body 2 having a plurality of combustion chambers 2A therein, in addition to a hybrid coupling 100 described later. The engine main body 2 illustrated in fig. 1 is a three-cylinder engine having three combustion chambers 2A.

The engine 1 further includes an intake passage 3, an air cleaner 4, an exhaust turbocharger 5 having a turbine 5A and a compressor 5B, an after cooler 6, and an intake manifold 7.

The intake passage 3 is a passage for introducing outside air into the engine body 2. The air cleaner 4, the compressor 5B of the exhaust turbocharger 5, and the after cooler 6 are arranged in this order in the direction toward the engine main body 2 in the intake passage 3.

The exhaust turbocharger 5 compresses outside air that has entered through the air cleaner 4 by using exhaust gas discharged from the engine main body 2. The turbine 5A of the exhaust turbocharger 5 is rotated by the exhaust energy of the exhaust gas. The compressor 5B of the exhaust turbocharger 5 rotates together with the turbine 5A to compress outside air.

The aftercooler 6 cools the air (outside air) compressed by the exhaust turbocharger 5 to have a high temperature.

The intake manifold 7 is provided between the engine body 2 and the intake passage 3, and distributes air (outside air) flowing from the intake passage 3 to the combustion chambers 2A. The intake manifold 7 of the present embodiment has a main flow portion 7A, through which air from the intake path 3 flows, extending in the direction of arrangement of the combustion chambers 2A, and a plurality of (three in the illustrated example) branch portions 7B extending from the main flow portion 7A to the respective combustion chambers 2A. The plurality of branch portions 7B are connected to the main flow portion 7A at positions spaced apart from each other in the extending direction of the main flow portion 7A, respectively. Therefore, in the intake manifold 7 of the present embodiment, the lengths of the plurality of paths from the inlet thereof to the respective combustion chambers 2A are different from each other. Note that, in the intake manifold 7, for example, the lengths of the plurality of paths may be equal to each other.

The engine 1 further includes an exhaust passage 8, an exhaust manifold 9, an EGR passage 10, an EGR cooler 11, and an EGR valve 12.

The exhaust passage 8 is a passage for discharging exhaust gas from the engine main body 2. A turbine 5A of the exhaust turbocharger 5 is disposed in the middle of the exhaust passage 8.

The exhaust manifold 9 is provided between the engine body 2 and the exhaust passage 8, and concentrates the exhaust gas discharged from each combustion chamber 2A of the engine body 2 into the exhaust passage 8.

The EGR path 10 extends from the exhaust manifold 9 to a point in the intake path 3 between the after cooler 6 and the intake manifold 7. Note that the EGR path 10 may extend from the exhaust path 8 to the intake path 3, for example. The EGR path 10 is a path for taking out a part of the exhaust gas discharged from the engine body 2 as EGR gas and returning it to the intake path 3. The EGR cooler 11 and the EGR valve 12 are arranged in this order in the direction toward the intake path 3 in the EGR path 10.

The EGR cooler 11 cools the EGR gas.

The EGR valve 12 opens and closes the EGR path 10. The EGR valve 12 opens the EGR path 10 when the pressure of the EGR gas (exhaust gas) in the EGR path 10 is higher than the pressure of the outside air passing through the intake path 3. This allows the EGR gas to be returned to the intake passage 3. The opening and closing of the EGR valve 12 is controlled by an engine controller (not shown) based on detection signals from NOx amount detection means (not shown) provided in the exhaust passage 8 and the exhaust manifold 9.

< hybrid connector >

The hybrid connector 100 constitutes a portion where the intake passage 3 and the EGR passage 10 merge. The hybrid connector 100 will be explained below.

The hybrid connector 100 of the present embodiment is a casting. As shown in fig. 2 and 3, the hybrid connector 100 includes an intake passage 101, a heater 102, an EGR passage 103, and a junction 104. Fig. 3 shows an internal passage of the hybrid connector 100 including the intake passage 101 and the EGR passage 103.

The intake passage 101 is a passage for introducing outside air into the engine body 2, and includes an inlet 101A and an outlet 101B. The inlet 101A of the intake passage 101 is connected to the downstream side of the aftercooler 6 in the intake path 3 shown in fig. 1. The outlet 101B of the intake passage 101 is connected to the engine main body 2 shown in fig. 1. Thus, the outside air from the aftercooler 6 flows into the engine main body 2 through the intake passage 101 of the hybrid connector 100. The intake passage 101 may be disposed, for example, in the middle of the intake passage 3, or may be disposed, for example, between the intake passage 3 and the intake manifold 7.

The intake passage 101 may be formed linearly, for example. As shown in fig. 5 and 6, the intake passage 101 of the present embodiment is curved at a middle portion in the longitudinal direction of the intake passage 101. Specifically, the intake passage 101 includes an upstream passage 111, a downstream passage 112 extending in a direction different from that of the upstream passage 111, and a curved passage 113 connecting the upstream passage 111 and the downstream passage 112.

The upstream passage 111 includes an inlet 101A of the intake passage 101. The downstream passage 112 is located on the downstream end side of the upstream passage 111, and includes the outlet 101B of the intake passage 101. The length of the downstream passage 112 in the illustrated example is shorter than the length of the upstream passage 111, but is not limited thereto. The upstream passage 111 and the downstream passage 112 extend linearly. The upstream passage 111 and the downstream passage 112 may intersect at an arbitrary angle, and in the present embodiment, they are orthogonal to each other. In the illustrated example, the upstream passage 111 extends in the Z-axis direction, and the downstream passage 112 extends in the X-axis direction orthogonal to the Z-axis direction. The curved passage 113 may be at least a curved passage. The curved passage 113 of the present embodiment is curved so as to smoothly connect the upstream passage 111 and the downstream passage 112.

The intake passage 101 of the present embodiment is formed in a tapered shape, that is, the flow path cross section of the intake passage 101 becomes smaller from the introduction port 101A to the discharge port 101B. In particular, the upstream passage 111 is formed in a tapered shape.

The heater 102 is provided at the inlet 101A of the intake passage 101. The heater 102 heats the outside air when the temperature of the outside air is low, for example. This can suppress or prevent the introduction of the outside air having an excessively low temperature into the combustion chamber 2A of the engine body 2 (see fig. 1).

As shown in fig. 3, 4, and 8, the EGR passage 103 is a passage for taking out a part of the exhaust gas discharged from the engine body 2 as EGR gas and returning it to the intake passage 101. In the present embodiment, the EGR passage 103 constitutes the downstream end of the EGR path 10 (see fig. 1). As illustrated in fig. 2 and 3, the number of introduction ports 103A of the EGR passage 103 connected to the EGR passage 10 may be plural (two in the illustrated example), but may be one, for example. The EGR passage 103 illustrated in fig. 3 is formed in a tapered shape, that is, the flow path cross section of the EGR passage 103 becomes smaller from the introduction port 103A toward the intake passage 101, but is not limited thereto.

As shown in fig. 3, 4, and 8, the junction 104 connects the EGR passage 103 to an intermediate portion in the longitudinal direction of the intake passage 101 such that the longitudinal directions of the intake passage 101 and the EGR passage 103 intersect with each other. The junction 104 of the present embodiment connects the EGR passage 103 to an intermediate portion of the intake passage 101 so that the longitudinal directions of the intake passage 101 and the EGR passage 103 are orthogonal to each other.

The joining portion 104 includes a downstream end of the EGR passage 103 that opens on the inner surface of the intake passage 101. The downstream end of the EGR passage 103 is an inlet 104A of EGR gas to the intake passage 101. In the following description, the downstream end of the EGR passage 103 may be referred to as an inlet 104A of the junction 104.

As shown in fig. 5 and 7, the merging portion 104 (particularly, the inflow port 104A) is located at an upstream end portion of the downstream passage 112 located on the curved passage 113 side in the longitudinal direction of the downstream passage 112. In the present embodiment, a part of the merging portion 104 (particularly, the inflow port 104A) is also located at the downstream end of the curved passage 113 on the upstream side of the downstream passage 112. The merging portion 104 is located on the rear side of a later-described convex portion 105 as viewed from the direction (Y-axis direction) shown in fig. 5.

As shown in fig. 4 and 5, in the inner surface of the downstream passage 112, the inflow port 104A of the joining portion 104 in the present embodiment opens in a region between an inner region 112A of the downstream passage 112 corresponding to the radially inner side of the curved passage 113 and an outer region 112B of the downstream passage 112 corresponding to the radially outer side of the curved passage 113 in the circumferential direction of the inner surface of the downstream passage 112. Thus, the direction in which the EGR gas flows from the EGR passage 103 into the intake passage 101 is substantially orthogonal to the longitudinal direction of the downstream-side passage 112 (the X-axis direction in fig. 5) and the radial direction of the curved passage 113 at the downstream end of the curved passage 113 (the Z-axis direction in fig. 5) (the Y-axis direction in fig. 5).

As shown in fig. 8, the inner surface of the intake passage 101 includes an upstream side region 116, the upstream side region 116 being located closer to the inlet 101A of the intake passage 101 than the joining portion 104 in the opposite wall surface 115, and the opposite wall surface 115 constituting the inner surface of the intake passage 101 and being located on the opposite side of the joining portion 104 (particularly, the inlet 104A) in the direction (the Z-axis direction in fig. 8) orthogonal to the longitudinal direction of the intake passage 101. The upstream side region 116 in the present embodiment constitutes the inner surface of the upstream side passage 111 in the intake passage 101.

The upstream region 116 includes a first wall surface 116A, a second wall surface 116B, and a third wall surface 116C. The first wall surface 116A and the second wall surface 116B are arranged in this order with a gap in the longitudinal direction of the intake passage 101 from the joining portion 104 side to the introduction port 101A. The third wall surface 116C protrudes inward (radially inward of the intake passage 101) with respect to the first wall surface 116A between the first wall surface 116A and the second wall surface 116B.

In the present embodiment, the third wall surface 116C is an inclined surface that is inclined so as to extend toward the inlet 101A in the longitudinal direction of the intake passage 101 as extending from the end of the first wall surface 116A on the inlet 101A side toward the inside of the first wall surface 116A.

The first wall surface 116A and the third wall surface 116C are continuous with each other in a curved surface. Similarly, the second wall surface 116B is continuous with the third wall surface 116C in a curved surface. That is, the first wall 116A is smoothly connected to the third wall 116C, and the second wall 116B is smoothly connected to the third wall 116C.

In the present embodiment, the second wall surface 116B is located inside the first wall surface 116A. The first wall surface 116A and the second wall surface 116B are arranged parallel to each other in the longitudinal direction of the intake passage 101 as shown in the drawing, but the present invention is not limited thereto.

Further, an upstream facing region 117 of the inner surface of the intake passage 101, which faces the first to third wall surfaces 116A to 116C in the radial direction of the intake passage 101, is curved so that the interval between the upstream facing region and the second wall surface 116B is larger than the interval between the upstream facing region and the first wall surface 116A. This enables the intake passage 101 (particularly, the upstream passage 111) to be tapered.

As shown in fig. 4 to 6, the hybrid connector 100 of the present embodiment further includes a convex portion 105. The convex portion 105 protrudes in the Z-axis negative direction from the inner region 112A toward the outer region 112B of the downstream passage 112. As shown in fig. 7, the convex portion 105 is located between the joining portion 104 (the inlet 104A) and the facing region 118, and faces the joining portion 104 (the inlet 104A), and the facing region 118 is a region facing the joining portion 104 (the inlet 104A) in the opposite wall surface 115 of the intake passage 101. The convex portions 105 are arranged at intervals in the Y-axis direction from both the facing region 118 and the inlet 104A of the junction 104.

As shown in fig. 4 to 6, a gap is formed between the front end of the projection 105 in the projection direction and the outer region 112B of the downstream passage 112. That is, the tip of the projection 105 does not reach the outer region 112B of the downstream passage 112. The protruding length of the convex portion 105 in the present embodiment is about half of the length from the inner region 112A to the outer region 112B, but is not limited thereto.

As shown in fig. 5, the convex portion 105 may face the entire inlet 104A of the junction 104, for example, when viewed in a direction (Y-axis direction) in which the convex portion 105 is juxtaposed with the inlet 104A of the junction 104, but in the present embodiment, faces a part of the inlet 104A of the junction 104. Specifically, the convex portion 105 faces a portion of the inlet 104A close to the inner region 112A of the downstream passage 112, but does not face a portion of the inlet close to the outer region 112B of the downstream passage 112.

Thereby, the flow of EGR gas flowing from the EGR passage 103 into the portion of the downstream-side passage 112 close to the inner region 112A is blocked by the convex portion 105. On the other hand, the flow of EGR gas flowing from the EGR passage 103 into the portion of the downstream passage 112 close to the outer region 112B reaches the facing region 118 without being blocked by the convex portion 105 (see fig. 4).

As shown in fig. 5 and 6, an end portion 105A of the convex portion 105 located on the upstream side of the intake passage 101 is inclined from the upstream passage 111 toward the downstream passage 112 (i.e., toward the outlet 101B of the intake passage 101) as going from the base end of the convex portion 105 in the protruding direction toward the leading end.

The upstream end 105A of the projection 105 may be located at the upstream end of the downstream passage 112 as shown in the drawing, or may be located at a position spaced downstream from the upstream end of the downstream passage 112. On the other hand, the downstream end 105B of the convex portion 105 may be located at the outlet 101B of the intake passage 101 as shown in the drawing, or may be located at a position spaced apart from the outlet 101B of the intake passage 101 toward the upstream side of the downstream passage 112.

The convex portion 105 may be formed in any shape. As shown in fig. 4 and 8, the convex portion 105 of the present embodiment is formed in a plate shape having a direction in which the convex portion 105 and the inlet 104A of the merging portion 104 are juxtaposed (Y-axis direction in fig. 4 and 8) in the plate thickness direction.

As shown in fig. 4 and 6 to 8, a recessed portion 120 recessed from the opposite wall surface 115 is formed in an opposing region 118 of the opposite wall surface 115 of the intake passage 101. In the present embodiment, the recess 120 is formed at the upstream end of the downstream side passage 112 in the opposing region 118. The recess 120 of the present embodiment is formed to extend to the downstream end of the curved passage 113 (see fig. 6 and 7 in particular). The inner surface of the recess 120 may be formed in any shape, and in the present embodiment, as shown in fig. 8, the inner surface of the recess 120 is formed in an arc shape smoothly curved in a cross section orthogonal to the longitudinal direction (X-axis direction) of the downstream passage 112.

< action Effect >

In the hybrid connector 100 of the present embodiment configured as described above, as shown in fig. 8, the EGR gas flowing from the EGR passage 103 into the intake passage 101 mainly flows from the inlet 104A of the junction 104 to the facing region 118 of the opposite wall surface 115 facing the inlet 104A.

Part of the flow of EGR gas flowing into the intake passage 101 is blocked by the convex portion 105. That is, the flow of a part of the EGR gas flowing into the intake passage 101 is attenuated by the convex portion 105. This can suppress backflow of the EGR gas from the merging portion 104 to the inlet 101A of the intake passage 101. An arrow F1 in fig. 8 shows an example of the flow of EGR gas being blocked by the convex portion 105.

Further, a part of the flow of the EGR gas flowing from the EGR passage 103 into the intake passage 101 passes through a gap between the tip of the convex portion 105 and the outer region 112B of the downstream passage 112, and reaches the facing region 118 facing the inlet 104A of the junction 104. Here, since the recess 120 is formed in the opposing region 118, a part of the EGR gas flows into the recess 120. Therefore, the EGR gas can be retained in the recess 120. This can suppress backflow of the EGR gas from the merging portion 104 to the inlet 101A of the intake passage 101. An arrow F2 in fig. 8 shows an example of the flow of EGR gas that stagnates in the recess 120.

Further, a part of the EGR gas reaching the facing region 118 of the opposite wall surface 115 may flow toward the introduction port 101A of the intake passage 101 along the first wall surface 116A of the opposite wall surface 115, which is located on the upstream side of the facing region 118. In this case, the flow direction of the EGR gas along the first wall surface 116A is changed by the third wall surface 116C protruding inward of the first wall surface 116A. Specifically, the third wall surface 116C reduces the flow component of the EGR gas toward the introduction port 101A, and increases the flow component of the EGR gas toward the radially inner side of the upstream inner surface. That is, the flow of the EGR gas toward the introduction port 101A is attenuated by the third wall 116C. This can prevent the EGR gas from reaching the inlet 101A of the intake passage 101 and the heater 102. An arrow F3 in fig. 8 shows an example of the flow of EGR gas attenuated by the third wall surface 116C.

In the hybrid connector 100 of the present embodiment, as shown in fig. 5, the outside air flows through the upstream passage 111, the curved passage 113, and the downstream passage 112 in this order from the inlet port 101A to the outlet port 101B of the intake passage 101. Therefore, in the curved passage 113, the flow velocity of the outside air flow F41 on the radially outer side thereof is larger than the flow velocity of the outside air flow F42 on the radially inner side thereof. The convex portion 105 is disposed in a region of the downstream passage 112 corresponding to the radially inner side of the curved passage 113, but is not disposed in a region corresponding to the radially outer side of the curved passage 113. Therefore, the relatively fast flow F41 of outside air radially outside the curved passage 113 reaches the outlet port 101B of the intake passage 101 without being blocked by the protrusion 105 and without being decelerated.

On the other hand, the convex portion 105 blocks the flow of the EGR gas flowing into the intake passage 101 in a region corresponding to the radially inner side of the curved passage 113 in the downstream passage 112 (i.e., a region where the flow velocity of the outside air is small) (particularly, refer to an arrow F1 in fig. 8). Therefore, the flow velocity of the EGR gas flowing into the intake passage 101 can be effectively reduced. Thus, the flow F41 of the relatively fast outside air radially outside the curved passage 113 is not obstructed or is difficult to be obstructed by the flow of the EGR gas flowing into the intake passage 101. Further, in the region corresponding to the radially inner side of the curved passage 113 where the flow velocity of the outside air is small, the EGR gas whose flow velocity is reduced by the convex portion 105 is favorably mixed with the outside air whose flow velocity is small.

The EGR gas whose flow velocity is reduced by the convex portion 105 is multiplied by the relatively fast flow F41 of the outside air radially outside the curved passage 113. Thereby, the EGR gas flows from the lead-out port 101B of the intake passage 101 to the engine body 2 at a high flow speed together with the outside air.

As described above, according to the hybrid connector 100 and the engine 1 of the present embodiment, the first wall surface 116A, the third wall surface 116C, and the second wall surface 116B are arranged in this order from the joining portion 104 side to the introduction port 101A in the upstream region 116 of the opposite wall surface 115 of the intake passage 101 located on the opposite side to the joining portion 104. The third wall surface 116C protrudes inward from the first wall surface 116A. Therefore, even if the EGR gas flowing into the intake passage 101 at the junction 104 flows back to the inlet 101A along the first wall surface 116A, the flow direction of the EGR gas is changed by the third wall surface 116C. This can suppress the EGR gas from reaching the introduction port 101A of the intake passage 101. Therefore, the adhesion of the soot contained in the EGR gas to the heater 102 provided at the introduction port 101A can be suppressed, and the performance degradation of the heater 102 can be suppressed.

In the hybrid connector 100 according to the present embodiment, the third wall surface 116C is an inclined surface, the first wall surface 116A and the third wall surface 116C are smoothly continuous with a curved surface, and the second wall surface 116B and the third wall surface 116C are also smoothly continuous with a curved surface. Therefore, the first to third wall surfaces 116A to 116C can suppress the occurrence of pressure loss in the outside air flowing through the intake passage 101 (particularly, the upstream passage 111).

Further, according to the hybrid connector 100 of the present embodiment, the convex portion 105 provided on the inner surface of the downstream passage 112 is provided to attenuate the flow of the EGR gas flowing into the intake passage 101 from the inlet 104A of the merging portion 104. The convex portion 105 is provided so as not to obstruct the flow F41 of the relatively fast outside air radially outside the curved passage 113. Therefore, the outside air can be made to flow from the outlet port 101B of the intake passage 101 to the engine main body 2 at a high flow speed. Further, the EGR gas whose flow velocity is reduced by the convex portion 105 can be made to flow from the lead-out port 101B of the intake passage 101 to the engine body 2 at a high flow velocity together with the outside air by the flow F41 of the outside air radially outside the curved passage 113.

This enables the EGR gas having a high specific gravity to be reliably supplied to the combustion chamber 2A of the engine body 2 with a fast flow of the outside air. Even if the lengths of the plurality of paths from the inlet to the respective combustion chambers 2A are different from each other as in the intake manifold 7 of the present embodiment, the EGR gas having a large specific gravity can be uniformly supplied to all the combustion chambers 2A while being multiplied by the rapid flow of the outside air. That is, the mixture gas having the uniform concentration of the EGR gas can be supplied to all the combustion chambers 2A of the engine body 2.

In addition, according to the hybrid connector 100 of the present embodiment, the upstream-side end 105A of the convex portion 105 is inclined from the upstream-side passage 111 toward the downstream-side passage 112 as going from the base end toward the leading end in the protruding direction of the convex portion 105. Therefore, the pressure loss of the outside air flowing through the intake passage 101 (particularly, the outside air flowing radially inward of the curved passage 113) caused by the convex portion 105 can be reduced. That is, the flow of the outside air in the intake passage 101 can be suppressed from being weakened by the convex portion 105.

Further, according to the hybrid connector 100 of the present embodiment, by forming the recessed portion 120 in the facing region 118 of the inner surface of the intake passage 101 that faces the joining portion 104, the EGR gas that has flowed into the intake passage 101 from the inlet 104A of the joining portion 104 can be retained in the recessed portion 120. This can suppress backflow of the EGR gas from the junction 104 to the inlet 101A of the intake passage 101, and can more effectively suppress adhesion of the soot contained in the EGR gas to the heater 102 provided at the inlet 101A.

Backflow of the EGR gas from the merging portion 104 to the introduction port 101A of the intake passage 101 is likely to occur in the engine 1 in which the number of combustion chambers 2A (the number of cylinders) is three as in the present embodiment. Therefore, the hybrid connector 100 according to the present embodiment, which can suppress the backflow of the EGR gas, is particularly effective when applied to a three-cylinder engine as in the present embodiment.

< other embodiments >

The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and can be modified as appropriate within a range not departing from the technical spirit of the present invention.

In the hybrid connector of the present invention, when the second wall surface 116B is located inward of the first wall surface 116A, the third wall surface 116C located between the first wall surface 116A and the second wall surface 116B may be, for example, a stepped surface connecting the first wall surface 116A and the second wall surface 116B in a stepped manner. That is, the third wall surface 116C may be orthogonal to the first wall surface 116A.

The third wall surface 116C located between the first wall surface 116A and the second wall surface 116B may be formed of, for example, a protrusion protruding inward from the first wall surface 116A and the second wall surface 116B. In this case, the second wall surface 116B may be located inward of the first wall surface 116A as in the above-described embodiment, but is not limited thereto.

In the hybrid connector of the present invention, the convex portion 105 may protrude from the outer region 112B to the inner region 112A of the downstream passage 112, for example. In this case, the flow of the EGR gas flowing from the EGR passage 103 into the intake passage 101 can be attenuated (the flow speed can be reduced) by the convex portion 105. Thus, the EGR gas can be suppressed from reaching the heater 102.

In the hybrid connector of the present invention, the inlet 104A of the junction 104 may be opened, for example, in the outer region 112B and the inner region 112A of the inner surface of the downstream passage 112.

In the hybrid connector of the present invention, the merging portion 104 may connect the EGR passage 103 to an intermediate portion of the intake passage 101, for example, so that the EGR passage 103 extends in the longitudinal direction of the intake passage 101 as being apart from the intake passage 101 in the radial direction of the intake passage 101. In this case, the direction in which the EGR gas flows from the EGR passage 103 into the intake passage 101 may include a component in a direction toward the downstream side of the intake passage 101. This can suppress backflow of the EGR gas to a position upstream of the intake passage 101 from the junction 104.

The engine of the present invention can be applied to any work vehicle such as a dump truck, a hydraulic excavator, a bulldozer, a motor grader, and a crane.

Description of the reference numerals

1 … engine, 2 … engine body, 3 … intake path, 7 … intake manifold, 8 … exhaust path, 9 … exhaust manifold, 10 … EGR path, 100 … hybrid connector, 101 … intake path, 101a … inlet port, 101B … outlet port, 102 … heater, 103 … EGR path, 104 … merging portion, 105 … convex portion, end portion of upstream side of 105a … convex portion 105, 111 … upstream side path, 112 … downstream side path, region inside 112a …, region outside 112B …, 113 … curved path, opposite wall surface 115 …, region upstream side 116 …, first wall surface 116a …, second wall surface 116B …, third wall surface 116C …, region opposite to 118, 118 …, 120 … concave portion.