JP2019173720A - Egr device of internal combustion engine - Google Patents

Abstract

To provide an EGR device superior in a thermal expansion absorption function of a catalyst case.SOLUTION: An EGR device has an EGR takeout pipe 13 connected to a catalyst case 9, an EGR cooler 14 connected to the EGR take-out pipe 13, and an intermediate pipe 15 connected to the EGR cooler 14, and the intermediate pipe 15 is fixed to a cylinder head 2 through a flange plate 16. The EGR take-out pipe 13 has a plurality of bent portions and has a meandering shape. Further the catalyst case 9 and the EGR cooler 14 have an inverted truncated shape in a side view. As thermal expansion of the catalyst case 9 is absorbed by bending deformation of the EGR take-out pipe 13, a large load is not applied to a joining portion of the intermediate pipe 15 and the flange plate 16.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an EGR device for an internal combustion engine.

  In an internal combustion engine for automobiles or the like, it is widely performed to provide an EGR device that recirculates a part of exhaust gas to an intake system in order to promote purification of exhaust gas. The EGR device often includes a water-cooled EGR cooler to cool the EGR gas.

  As an example of an EGR device equipped with an EGR cooler, Patent Document 1 discloses that an EGR take-off pipe (upstream EGR pipe) is connected to the lower end of the catalyst case, and an EGR take-off pipe is connected to the upper end of the EGR take-off pipe. In the configuration in which the cooler is connected and the upper end of the EGR cooler is connected to the EGR valve, the EGR take-out pipe is formed in a substantially inverted L-shape when viewed from the direction facing the exhaust side of the engine body, thereby It is disclosed that thermal expansion is absorbed by bending deformation of the EGR take-out pipe.

Japanese Patent No. 5805206

  In Patent Document 1, the lower end of the EGR take-out pipe is connected to the front surface of the catalyst case as viewed from the direction orthogonal to the exhaust side surface of the engine body. Therefore, the EGR take-out pipe largely protrudes outside the exhaust side of the engine main body. However, in this configuration, when other members are arranged outside the exhaust side of the engine main body, the other members come into contact with the EGR take-out pipe. Since the arrangement position must be selected so that there is no problem, the freedom of design of the engine is impaired, and there is a concern that the engine will be enlarged.

  The present invention has been made to improve the current situation.

The EGR device of the present invention is
“An exhaust passage through which the exhaust gas discharged from the cylinder head flows, an EGR takeout pipe branched from the exhaust passage, and an EGR cooler connected to the end of the EGR takeout pipe are arranged on the exhaust side surface of the engine body. ing"
This is the basic configuration.

And, the invention of claim 1 is the above basic configuration,
“The EGR cooler is disposed on the side of the exhaust passage in a side view opposite to the exhaust side of the engine body, and a part of the EGR take-out pipe extends behind the exhaust passage in the side view. It has a meandering shape to pass through. ''
It is the composition.

Further, the invention of claim 2 is the above basic configuration,
“The exhaust passage and the EGR cooler are arranged in a substantially C-shaped (or V-shaped) posture in which the interval increases upward in a side view facing the exhaust side of the engine body.”
It is the composition.

The present invention further has various configurations. For example, in the invention of claim 3, in claim 1 or 2,
“While the exhaust passage has a catalyst case,
The EGR cooler is a box shape whose cross-sectional shape is substantially rectangular in a direction facing the exhaust side of the engine body, and the EGR cooler is disposed on the side of the catalyst case in the side view. ing"
It is the composition.

  As a development example of claim 3, in claim 4, the upper end portion of the EGR cooler is fixed directly to the engine body via a bracket or via a flange plate.

  The invention of claim 1 does not conflict with the invention of claim 2. It is preferable to combine them with each other.

  In the first aspect of the present invention, the EGR take-out pipe has a meandering shape and is easily bent and deformed, so that the exhaust passage is thermally expanded and can absorb the elongation accurately. Therefore, the EGR cooler is not pulled strongly due to the thermal expansion of the exhaust passage, and the EGR cooler can be stably held.

  A part of the EGR take-out pipe is located behind the exhaust passage (a space between the exhaust passage and the engine body), and the EGR take-out pipe is entirely outside the exhaust passage (on the opposite side of the cylinder block). ) Can be placed in a state that does not protrude. That is, although the space between the exhaust passage and the engine body is a dead space, the dead space can be used to form the EGR take-out pipe in a meandering form.

  Therefore, when other members are arranged outside the exhaust passage of the engine body, the EGR take-out pipe does not get in the way, so that the design freedom can be improved and the internal combustion engine can be made compact.

  In the invention of claim 2, when the exhaust passage is thermally expanded and deformed, the EGR cooler is subjected to an action of rotating with the attachment portion to the engine body as a fulcrum. Therefore, there is almost no tensile force acting on the EGR cooler, and the joint portion with the cylinder head can be prevented from being damaged or deformed.

  Therefore, even in the invention of claim 2, the EGR take-out pipe that protrudes outside the exhaust passage as in Patent Document 1 is unnecessary, and as a result, the design freedom can be improved and the internal combustion engine can be improved as in the case of claim 1. It can also contribute to downsizing the engine.

  A catalyst case is generally arranged in the exhaust passage. However, since the catalyst case has a considerable outer diameter, a large space is vacant on the side of the catalyst case in a side view. In the invention of claim 3, the EGR cooler can be arranged by effectively utilizing the space on the side of the catalyst case. That is, according to the third aspect, since the EGR cooler has a cross-sectional shape that is long in the depth direction (long in a direction perpendicular to the crank axis) in the side view of the engine, the EGR cooler in the side view of the engine The arrangement area (projected area) can be reduced. Therefore, in arranging other members, it is possible to suppress the time and effort of designing so as to avoid interference with the EGR cooler, thereby contributing to improvement in design freedom.

  If the structure of Claim 4 is employ | adopted, since the attachment of an EGR cooler is reinforced with a bracket, the stability of an EGR cooler can further be improved.

1 is a schematic side view of an internal combustion engine. It is the II-II perspective view (rear view) of FIG. It is the elements on larger scale of FIG. (A) is a rear view of IVA-IVA in FIG. 3, and (B) is a partially broken plan view of IVA-IVA in FIG.

(1). Outline Next, an embodiment of the present invention will be described with reference to the drawings. In the following, words such as front and rear and side view are used to specify the direction, but the front and rear direction is the crank axis direction, and the side on which the timing chain and crank pulley (not shown) are provided is the front. . The vertical direction is a vertical direction, and the horizontal direction is a direction perpendicular to the vertical direction and the crank axis direction. As a precaution, the direction is clearly shown in the drawing.

  The basic configuration of the internal combustion engine is the same as that of the prior art. As shown in FIGS. 1 and 2, a cylinder block 1 having a plurality of cylinder bores (not shown) as a core member of the engine body and a top surface thereof are fixed. The cylinder head 2 is provided. In addition, the parallel diagonal line drawn in FIG. 1 is a display of the rear end surface of the cylinder block 1, and is not a display of a cross section.

  An oil pan 3 is fixed to the lower surface of the cylinder block 1, and a head cover 4 is fixed to the upper surface of the cylinder head 2. A cooling water distribution unit 5 is disposed on the rear surface of the cylinder head 2. A front cover 6 that covers the timing chain is fixed to the front surfaces of the cylinder block 1 and the cylinder head 2, and a front end portion of the head cover 4 overlaps the front cover 6 from the bore axis direction. A transmission case 7 is fixed to the rear surfaces of the cylinder block 1 and the oil pan 3 with a large number of bolts.

  The cylinder head 2 of the present embodiment is of a type having a built-in exhaust collecting portion. One exhaust outlet is opened on the exhaust side surface, and a catalyst is connected to this exhaust outlet via an elbow pipe 8 as a part of the exhaust passage. Case 9 is connected. The elbow pipe 8 includes a flange plate 10 which is fixed to the cylinder head 2 with bolts (and nuts).

  The catalyst case 9 includes a straight portion 9a containing a catalyst, an upper conical upper cone portion 9b integrally provided at the upper end thereof, and a lower constricted lower cone portion 9c integrally provided at the lower end of the straight portion 9a. An exhaust joint pipe 12 having a flange plate 11 is integrally provided at the lower end of the lower cone portion 9c.

  As shown in FIGS. 1 and 3, the catalyst case 9 is inclined at a slight angle with respect to the vertical line so as to shift backward as it goes downward in a side view. Further, as shown in FIG. 2, the rear view (and front view) is inclined so as to be slightly separated from the cylinder block 1 as it goes downward (the inclination in the rear view is slight, and the exhaust side surface of the cylinder block 1). Can be said to be substantially parallel.)

(2) EGR device Next, the EGR device will be described. The lower end (upstream end) of the EGR take-out pipe 13 for taking out the EGR gas is connected to the upper portion and the rear face portion of the lower cone portion 9c in the catalyst case 9 by welding or the like. 4B, the receiving member 9d into which the lower end of the EGR take-out pipe 13 is fitted is fixed to the lower cone portion 9c of the catalyst case 9 by welding, but the lower end of the EGR take-out pipe 13 is fixed to the lower cone portion 9c. You may form the cylinder part which inserts by burring.

  The EGR take-out pipe 13 meanders and extends upward, and an EGR cooler 14 is connected to the upper end (downstream end). The upper end of the EGR cooler 14 is a cylinder via an L-shaped intermediate pipe 15 and a flange plate 16. It is fixed to the rear side surface of the head 2. The EGR cooler 14 is disposed on the side (lateral direction) of the catalyst case 9 in a side view of the engine, and is disposed behind the catalyst case 9 in the direction of the engine.

  As shown in FIG. 2, an EGR internal passage 17 that opens to the exhaust side surface and the intake side surface is formed at the rear portion of the cylinder head 2, and the intermediate pipe 15 is connected to the start end of the EGR internal passage 17.

  As shown in FIGS. 1 and 3, the EGR take-out pipe 13 meanders in a substantially S shape when viewed from the side, and is bent into an inverted L shape when viewed from the rear as shown in FIG. Precisely, the EGR take-out pipe 13 has a first portion 13a connected to the catalyst case 9, a third portion 13c connected to the EGR cooler 14, and a second portion 13b connecting the two, The first portion 13 a and the second portion 13 b are connected via the first bent portion 18, and the second portion 13 b and the third portion 13 c are connected via the second bent portion 19.

  And the lower end of the 1st part 13a is connected to the substantially back part of the lower cone part 9c in the catalyst case 9, and it is so that it may approach the cylinder head 2 as it goes up in rear view as FIG. While tilting, it is tilted backwards in a side view.

  The first portion 13a and the second portion 13b are bent almost on the same plane. Therefore, as shown in FIG. 4A, the second portion 13b is inclined so as to approach the cylinder block 1 as it goes upward in the rear view, and is inclined forward as shown in FIG. 3 in the side view. Yes. That is, the first portion 13a and the second portion 13b are in opposite postures in a side view. As shown in FIG. 4B, the first portion 13a and the second portion 13b are formed in a square shape as a whole in plan view.

  The third portion 13c is inclined obliquely upward so as to face rearward and upward in a side view, and is separated from the cylinder block 1 as it goes upward as shown in FIG. 4A in the side view. Inclined. Therefore, the 2nd part 13b and the 3rd part 13c are curving loosely in the shape of a character as a whole. The second portion 13b and the third portion 13c have a U-turn shape as seen in FIG. 4B in plan view.

  Eventually, the EGR take-out pipe 13 meanders in an S-shape or close to it in a side view and a plan view, and is bent in an L shape in the rear view. That is, the EGR take-out pipe 13 meanders three-dimensionally, and easily bends and deforms in any of the vertical direction, the front-rear direction, and the left-right direction. Therefore, even if the catalyst case 9 thermally expands or swings in the front-rear direction or the left-right direction, the thermal expansion or swing motion can be easily absorbed by bending deformation.

  The EGR cooler 14 is a box shape whose cross-sectional shape is an elongated rectangle, and as shown in FIG. 3, the EGR cooler 14 is inclined so as to go backward as it goes upward as viewed from the side. Accordingly, when viewed from the side, the catalyst case 9 and the EGR cooler 14 have an inverted C-shaped posture (or a V-shaped posture) in which the interval increases upward.

  Of the EGR take-out pipe 13, the entire third portion 13c and about half of the second portion 13b are hidden behind the catalyst case 9 in a side view (exactly, between the catalyst case 9 and the cylinder block 1). In the space.) In the rear view of the engine, for example, as shown in FIG. 4A, the EGR cooler 14 and the catalyst case 9 overlap each other. However, since the EGR cooler 14 is disposed behind the catalyst case 9, EGR There is no contact between the cooler 14 and the catalyst case 9.

  Further, the EGR cooler 14 has a rectangular shape (cross-sectional shape) having a width direction X and a longitudinal direction Y when viewed from the axial direction, but as shown in FIG. It arrange | positions with the attitude | position from which the direction Y becomes a depth direction. Therefore, the area (projected area) in the side view is much smaller than when the width direction X is in the depth direction in the side view.

  The EGR cooler 14 is water-cooled, and a cooling water introduction port 20 is provided at the lower part and a cooling water discharge port 21 is provided at the upper part. The cooling water discharge port 21 and the cooling water introduction port 20 are arranged so as to be divided into left and right in the side view of FIG. 1 and FIG.

  The flange plate 16 fixed to the cylinder head 2 has a substantially longitudinal shape, and its front end and rear end are fixed to the cylinder head 2 with bolts. As shown in FIG. 4, the upper end portion of the EGR cooler 14 and the flange plate 16 are fixed by a bracket 22. The bracket 22 has an upper end welded to the flange plate 16 and a lower end welded to a side surface of the EGR cooler 14 (a surface facing the cylinder head 2). The upper end and the lower end are connected by an inclined portion. Yes.

  The bracket 22 is in a posture overlapping with the intermediate pipe 15 in a side view (therefore, the bracket 22 does not appear in FIGS. 1 and 3). The bracket 22 can also be fixed to the exhaust side of the cylinder head 2. However, if it fixes to the flange board 16 like this embodiment, since the whole EGR apparatus can be unitized, there exists an advantage that an attachment operation becomes easy.

(3) Summary As described above, the catalyst case 9 extends due to thermal expansion or shakes due to the vibration of the engine. These elongations and vibrations are absorbed by the EGR take-out pipe 13, and the intermediate pipe 15 A strong external force does not act on the joint between the flange plate 16 and the flange plate 16. Therefore, the phenomenon that the intermediate pipe 15 is detached from the flange plate 16 does not occur, and high durability can be maintained.

  Further, since the catalyst case 9 and the EGR cooler 14 are in an inverted C-shaped (or V-shaped) posture, when the catalyst case 9 is thermally expanded, the EGR take-out pipe 13 and the EGR cooler 14 are at the upper end of the intermediate pipe 15. The external force that rotates around the fulcrum is received, and the external force that pulls the EGR cooler 14 in the longitudinal direction is small.

  An external force that rotates the EGR take-out pipe 13 and the EGR cooler 14 is absorbed mainly by the deformation of the EGR take-out pipe 13. Also in this aspect, it is possible to prevent an excessive load from being applied to the joint portion between the intermediate pipe 15 and the flange plate 16 and to ensure high durability.

  In this embodiment, the EGR take-out pipe 13 is three-dimensionally bent and is in a state close to a spiral. For this reason, the EGR gas flows smoothly through the EGR take-out pipe 13. Therefore, it is possible to prevent the EGR gas from striking the bent portion and promoting the deterioration while making the EGR take-out pipe 13 meandering.

  Since the EGR cooler 14 is longer in the depth direction when viewed from the side of the engine, the area occupied by the EGR cooler 14 is smaller when viewed from the side. Therefore, in arranging other members behind the catalyst case 9, design freedom can be improved.

  The present invention can be embodied in various ways other than the above-described embodiment. For example, the upper end portion of the EGR cooler 14 may be directly fixed to the exhaust side surface of the cylinder head 2 without using the intermediate pipe 15. In the embodiment, the EGR take-out pipe 13 is meandered by providing two bent portions, but may be formed in a form having one or three or more bent portions, or may be formed in a spiral shape in which the bent portions are not clear. It is also possible.

  Further, the connection destination of the EGR take-out pipe is not necessarily the catalyst case, and can be connected to the exhaust pipe.

  The present invention can be embodied in an EGR device for an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 8 Elbow pipe which comprises an exhaust passage 9 Catalyst case which comprises an exhaust passage 13 EGR take-out pipe 13a 1st part 13b 2nd part 13c 3rd part 14 EGR cooler 1
15 Intermediate pipe 16 Flange plate 18, 19 Bent part 22 Bracket

Claims (4)

An exhaust passage through which exhaust gas discharged from the cylinder head flows, an EGR extraction pipe branched from the exhaust passage, and an EGR cooler connected to the end of the EGR extraction pipe are disposed on the exhaust side surface of the engine body. The configuration
The EGR cooler is disposed on the side of the exhaust passage in a side view facing the exhaust side of the engine body, and a part of the EGR take-out pipe passes behind the exhaust passage in the side view. Is in a meandering form,
EGR device for internal combustion engine. An exhaust passage through which exhaust gas discharged from the cylinder head flows, an EGR extraction pipe branched from the exhaust passage, and an EGR cooler connected to the end of the EGR extraction pipe are disposed on the exhaust side surface of the engine body. The configuration
The exhaust passage and the EGR cooler are arranged in a substantially C-shaped posture in which the interval is widened upward in a side view facing the exhaust side of the engine body.
EGR device for internal combustion engine. While the exhaust passage includes a catalyst case,
The EGR cooler is a box shape whose cross-sectional shape is substantially rectangular in a direction facing the exhaust side of the engine body, and the EGR cooler is disposed on the side of the catalyst case in the side view. ing,
An EGR device for an internal combustion engine according to claim 1 or 2. The upper end of the EGR cooler is fixed directly to the engine body via a bracket or via a flange plate,
An EGR device for an internal combustion engine according to claim 3.

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