JPH10281014A - Egr gas cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely arrange a heat exchanger within an engine room by arranging the heat exchanger cooling EGR gas by circulation of cooling water within an intake manifold, in an EGR gas cooling device for cooling EGR gas to be recirculated in the intake manifold. SOLUTION: A heat exchanger 21 which forms an EGR gas cooling device and is arranged within an intake manifold 23 is formed by joining a core part 27 to a supporting plate 25. A through hole 25b is formed at the center of this supporting plate 25 and an EGR gas piping is connected to the end face of a gas pipe 27 connected with this through hole 25b. Through holes 25c, 25d are formed on the upper and lower sides of the gas pipe 27 of the supporting plate 25. The core part 27 is constituted by laminating plural sheets of shells 37 in which a cooling water channel 35 is formed between a pair of plate members 33 and the center of each shell 37 is formed as an EGR gas passage 43. Further, a heat radiating fin 47 guiding EGR gas from the center to the side is arranged between the shells 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an EGR system for an exhaust system.
The present invention relates to an EGR gas cooling device for cooling EGR gas recirculated to an intake manifold via a pipe.

[0002]

2. Description of the Related Art Conventionally, in an engine, in order to reduce nitrogen oxides (NOx) in the exhaust gas, a part of the exhaust gas is taken out of an exhaust system and added to an air-fuel mixture.
(Exhaust Gas Recirculation). An EGR device for performing such EGR includes:
A part of the exhaust gas from the exhaust system is configured to be recirculated as an EGR gas to the air-fuel mixture sucked into the combustion chamber. For example, as shown in FIG. 8, an exhaust manifold (or an exhaust pipe) 1 An EGR passage 3 connecting the intake manifold 2 and an EGR passage provided in the EGR passage 3
And a valve 4.

[0003] The ratio of the EGR gas to the intake air-fuel mixture is adjusted by appropriately controlling the opening of the EGR valve 4 according to the operating state of the engine. Such an E
In the GR device, since the EGR gas is taken into the combustion chamber together with the air-fuel mixture, it is necessary to maintain the temperature of the EGR gas at an appropriate temperature. That is, the EGR gas is naturally high in temperature, but if the temperature of the EGR gas is too high, the air-fuel mixture is heated and thermally expanded, thereby lowering the air charging efficiency and deteriorating the combustion rate of the air-fuel mixture. The output of the engine may be reduced.

On the other hand, if the temperature of the EGR gas is too low,
The viscosity of the adhering substance such as tar in the GR gas increases, so that the adhering substance easily adheres to the EGR passage, the EGR valve, and the like, which may reduce the reliability of the apparatus. Conventionally, as an EGR device provided with a cooling device for cooling EGR gas, for example,
Japanese Unexamined Patent Application Publication No. 7-180620 and the like are known.

FIG. 9 shows a cooling device arranged in this type of EGR device. This cooling device is arranged in a pipe connecting the exhaust manifold and the EGR valve. This cooling device is configured by arranging a number of pipes 6 in the axial direction of the outer cylinder 5, and both ends of the pipes 6 are supported by end plates 7 as shown in FIG. 10. An inlet pipe 8 and an outlet pipe 9 for the cooling water are opened on the outer periphery of the outer cylinder 5.

Further, flange portions 10 and 11 are formed at the upper end and the lower end of the outer cylinder 5, respectively. A pipe 12 from the exhaust manifold is connected to the upper flange 10 via a mounting flange 13, and a pipe 14 to the EGR valve is connected to the lower flange 11 via a mounting flange 15. In this cooling device, the EGR gas is introduced into the outer cylinder 5 from the pipe 12 on the exhaust manifold side, cooled by the cooling water flowing between the pipes 6 in the outer cylinder 5, and then led to the pipe 14 on the EGR valve side. Is done.

[0007]

However, in such a conventional EGR gas cooling device, the cooling device is disposed between the pipe lines 12 and 14 connecting the exhaust manifold and the EGR valve. And the fixing of the cooling device is complicated, and there is a problem that it is difficult to lay out the cooling device in a narrow engine room.

The present invention has been made in order to solve such a conventional problem, and an EGR in which a heat exchanger as a cooling device can be easily and reliably arranged in an engine room.
It is an object to provide a gas cooling device.

[0009]

According to a first aspect of the present invention, there is provided an EGR gas cooling apparatus for cooling EGR gas recirculated from an exhaust system to an intake manifold via an EGR pipe.
In the gas cooling device, a heat exchanger that cools the EGR gas by circulating cooling water is disposed in the intake manifold.

According to a second aspect of the present invention, in the EGR gas cooling apparatus according to the first aspect, the heat exchanger directs the EGR gas flowing from one end in the axial direction of the core portion to the side. It is characterized by flowing out. The EGR gas cooling device according to claim 3 is the EGR gas cooling device according to claim 2, wherein the heat exchanger includes a plurality of shells each having a cooling water flow path formed between a pair of plate members, An EGR gas passage is formed in the center of the shell, and a radiation fin for guiding the EGR gas from the center to the side is disposed between the shells.

According to a fourth aspect of the present invention, there is provided the EGR gas cooling apparatus according to the second aspect, wherein the heat exchanger includes a plurality of heat radiating plates stacked at predetermined intervals and an EGR gas at the center of the heat radiating plate. A gas passage is formed, and a cooling water pipe is disposed through the heat radiation plate.

(Effect) In the EGR gas cooling device according to the first aspect, the EGR gas is cooled by circulating cooling water in the intake manifold.
A heat exchanger for cooling the gas is arranged, and the EGR gas cooled by the heat exchanger is led out into the intake manifold as it is.

[0013] In the EGR gas cooling device according to the second aspect, the EGR gas flowing from one end of the core portion of the heat exchanger in the axial direction is discharged to the side. In the EGR gas cooling device according to the third aspect, after the EGR gas flows from the EGR gas passage of the shell disposed at the end, the cooling water flows through the cooling water flow path between the pair of plate members via the radiation fins. And is discharged toward the side of the core.

[0014] In the EGR gas cooling device of the fourth aspect, the EG
After the R gas flows in from the EGR gas passage of the radiating plate disposed at the end, the R gas is cooled by the cooling water flowing through the cooling water pipe through the radiating plate and flows out toward the side of the core.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show a first embodiment of an EGR gas cooling apparatus according to the present invention. Reference numeral 21 denotes a heat exchanger disposed in an intake manifold 23. The heat exchanger 21 includes a core plate 2
7 are joined. The support plate 25 has a disk shape made of, for example, stainless steel, and has a mounting hole 25a formed on the outer peripheral side.

At the center of the support plate 25, a through hole 25 is provided.
b is formed, and the gas pipe 27 is connected to the through hole 25b. A flange 27 a to which an EGR gas pipe that has passed through an EGR valve (not shown) is connected is formed on an end surface of the gas pipe 27. Through holes 25c and 25d are formed above and below the gas pipe 27 of the support plate 25, to which the inlet pipe 29 and the outlet pipe 31 of the cooling water are connected.

In this embodiment, the core portion 27 is formed by laminating a plurality of circular shells 37 in which a cooling water passage 35 is formed between a pair of plate members 33 made of, for example, stainless steel. Each shell 37 has an inlet-side cup portion 39 communicating with the inlet pipe 29 and an outlet-side cup portion 41 communicating with the outlet pipe 31.

An EGR gas passage 43 is formed at the center of each shell 37, and the EGR gas passage 43 of the inner shell 37 is closed by a patch end 45. Radiation fins 47 for guiding the EGR gas from the center to the side are disposed between the shells 37. The heat radiation fins 47 are made of, for example, stainless steel, and are formed by forming circular corrugated fins without louvers.

An elongate through hole 47a is formed at the center of the radiation fin 47. The above-described EGR gas cooling device includes, as shown in FIG.
Gas pipe 27, inlet pipe 29 and outlet pipe 31
In a state where the core portion 27 in which the shells 37 and the heat radiation fins 47 are alternately laminated on the other side of the support plate 25 is assembled, for example, it is manufactured by nickel brazing.

As shown in FIG. 4, the EGR gas cooling device manufactured as described above has an intake manifold 23
The core 27 is inserted into a through hole 23b formed in the end surface 23a of the intake manifold 23, and the support plate 25 is fixed to the end surface 23a of the intake manifold 23 by bolts (not shown), and is fixed to the intake manifold 23. In the above-described EGR gas cooling device, the EGR gas that has passed through the EGR valve flows from the gas pipe 27 of the support plate 25 into the EGR gas passage 43 of the shell 37, and then flows between the pair of plate members 33 through the radiation fins 47. Is cooled by the cooling water flowing through the cooling water flow path 35, and flows out toward the side of the core portion 27.

The EGR gas flowing toward the side of the core 27 flows through the EGR gas flow path in the intake manifold 23 and is mixed with the intake air of the intake manifold 23. Further, cooling water from the engine side flows in from the inlet pipe 29, and cooling water from the outlet pipe 31 flows out to the upstream side of the water pump. In the EGR gas cooling device configured as described above, in the intake manifold 23,
Heat exchanger 21 for cooling EGR gas by cooling water circulation
Is arranged, the heat exchanger 21 as the cooling device can be easily and reliably arranged in the engine room.

In the above-described EGR gas cooling device,
Since the EGR gas flowing from one end in the axial direction of the core portion 27 of the heat exchanger 21 is configured to flow out toward the side of the core portion 27, the axial length of the core portion 27 is reduced. In addition, the heat exchanger can be made compact. That is, in the conventional EGR gas cooling device,
Since the gas flows linearly along the axial direction of the outer cylinder, in order to obtain a predetermined cooling performance, the EGR gas flow path and the cooling water flow path are relatively long, and the length of the outer cylinder is increased. However, in the above-described EGR gas cooling device, the core 27
Can be reduced, and the heat exchanger 21 can be made compact.

Further, in the above-described EGR gas cooling device, a plurality of shells 37 each having a cooling water passage 35 formed between a pair of plate members 33 are stacked, and
7, an EGR gas passage 43 is formed in the center of the heat exchanger 21, and a radiating fin 47 for guiding the EGR gas from the center to the side is arranged between the shells 37 to constitute the heat exchanger 21. The EGR gas that has flowed in from one end in the axial direction can easily and reliably flow out to the side.

Since the EGR gas is dispersed and discharged from between the shells 37, the EGR gas can be easily dispersed.
It can be done reliably. In addition, in the above-described EGR gas cooling device, since an outer cylinder is not required, at the time of periodic inspection or the like,
By removing the support plate 25 from the intake manifold 23, the clogging state of the radiation fins 47 is confirmed,
Cleaning and the like of the radiation fins 47 can be easily performed.

Further, in the above-described EGR gas cooling device, since the inlet pipe 29 and the outlet pipe 31 of the cooling water are provided on the support plate 25 and the gas pipe 27 of the EGR gas is provided, the workability of pipe installation is improved. be able to. Further, in the above-described EGR gas cooling device, since only one end of the core 27 is joined to the support plate 25, for example, the EGR gas rapidly flows into the core 27 cooled to the cooling water temperature, and the core 27 is cooled. Even when 27 expands, it is possible to reduce a possibility that a large thermal stress is generated in core portion 27.

Further, in the above-described EGR gas cooling device, the number of stacked shells 37 can be easily changed.
Heat exchange performance, EGR gas resistance, cooling water flow resistance, and the like can be easily changed. FIGS. 5 and 6 show a second embodiment of the EGR gas cooling device of the present invention, and reference numeral 51 denotes a heat exchanger disposed in the intake manifold 23.

This heat exchanger 51 is constituted by forming a core 55 on a support plate 53. Support plate 5
3 is, for example, in the shape of a disk made of stainless steel, and has a mounting hole 53a formed on the outer peripheral side. In the center of the support plate 53, a through hole 53b is formed.

Outside the support plate 53, a cooling water tank 57 made of, for example, stainless steel is arranged. This tank 57 has a bottomed cylindrical shape,
The partition plate 59 allows the inlet-side tank 61 and the outlet-side tank 6
3 and 2. A cooling water inlet pipe 65 is opened in the inlet tank 61, and a cooling water outlet pipe 67 is opened in the outlet tank 63.

At a position corresponding to the through hole 53b of the support plate 53, a cylindrical pipe 69 is disposed. The pipe 69 is connected to a gas pipe 71 through which EGR gas flows. A flange portion 71a is formed on an end surface of the gas pipe 71, to which an EGR gas pipe that has passed through an EGR valve (not shown) is connected.

In this embodiment, the core portion 55 is formed by laminating a plurality of heat radiation plates 73 made of, for example, stainless steel at predetermined intervals. At the center of each heat dissipation plate 73, a through hole 73a is formed, and an EGR gas passage 75 is formed. A bottom plate 77 made of, for example, stainless steel is disposed adjacent to the heat radiation plate 73 located at the downstream end.

The support plate 53, the heat radiating plate 73 and the bottom plate 77 have a large number of through holes 53f, 73f.
f, 77f are formed, and these through holes 53f, 73
The inlet pipe 79 and the outlet pipe 81 of the cooling water made of, for example, stainless steel are arranged so as to penetrate through the holes f and 77f. A return tank 83 for cooling water made of, for example, stainless steel is disposed so as to cover the bottom plate 77.

In the above-described EGR gas cooling device, a heat radiating plate 73 is disposed between the support plate 53 and the bottom plate 77, and the cooling water inflow side pipe 79 and the outflow side pipe 81 are disposed therethrough. With the core 55 attached, the gas pipe 7 is mounted on the support plate 53 on the side opposite to the core 55.
1, the tank 57 in which the inlet pipe 65 and the outlet pipe 67 are assembled is assembled, and the return tank 83 is assembled on the bottom plate 77 side, for example, by nickel brazing.

In the EGR gas cooling device manufactured as described above, the core 55 is inserted into the through hole 23b formed in the end face of the intake manifold 23, and the supporting plate 5
3 is fixed to the end face of the intake manifold 23 by a bolt (not shown), and is fixed to the intake manifold 23. In the above-described EGR gas cooling device, E
GR gas passes through gas pipe 71 and pipe 69,
After flowing into the EGR gas passage 75 of the core portion 55, the core portion 55 is cooled through the heat radiation plate 73 cooled by cooling water flowing through the inflow side tube 79 and the outflow side tube 81.
Is spilled toward the side of.

In the EGR gas cooling device configured as described above, a plurality of heat radiating plates 73 are stacked at predetermined intervals, an EGR gas passage 75 is formed in the center of the heat radiating plate 73, and the heat radiating plate 73 is inserted therethrough. Since the heat exchanger 51 is configured by arranging the inflow side pipe 79 and the outflow side pipe 81, the EGR gas flowing from one end of the heat exchanger 51 in the axial direction can be easily and reliably discharged to the side. can do.

Then, substantially the same effects as in the first embodiment can be obtained. In the above-described first and second embodiments, an example has been described in which the heat exchangers 21 and 51 are arranged near the inside of the end face of the intake manifold 23.
The present invention is not limited to such an embodiment. For example, the core portions 27 and 55 are spaced apart from the support plates 25 and 53, and the support plates 25 and 53 and the core portions 27 and 55 are separated from each other by EGR gas. The core portions 27 and 55 are connected by the intake manifold 2 and the cooling water passage.
3 at or near the branch to each cylinder,
The R gas may be directly distributed to each cylinder.

Further, in the first and second embodiments described above, an example in which the core portions 27 and 55 are formed in a circular shape has been described. However, the present invention is not limited to such an embodiment. It may be formed in a rectangular shape or the like. Furthermore, in the above-described second embodiment, an example in which the return tank 83 is disposed on the bottom plate 77 has been described. However, the present invention is not limited to this embodiment. 81, the return tank 83 may be eliminated.

In the above-described second embodiment, only the through hole 73a is formed at the center of the heat radiating plate 73, and the EG is formed.
Although the example in which the R gas passage 75 is formed has been described, the present invention is not limited to such an embodiment. For example, as shown in FIG. Distribution pipe 89 in which part 89a is formed
May be inserted to guide the EGR gas in a desired direction.

[0039]

As described above, in the EGR gas cooling device of the first aspect, the heat exchanger for cooling the EGR gas by circulating the cooling water is disposed in the intake manifold.
The heat exchanger as the cooling device can be easily and reliably arranged in the engine room. In the EGR gas cooling device according to the second aspect, the EGR gas flowing from one end in the axial direction of the core portion of the heat exchanger is configured to flow out toward the side of the core portion. Direction length,
The heat exchanger can be made compact.

In the EGR gas cooling device according to the third aspect, a plurality of shells each having a cooling water passage formed between a pair of plate members are stacked, and an EGR gas passage is formed at the center of the shell. Since the heat exchanger is configured by disposing radiating fins for guiding the EGR gas from the center to the side, the EGR flowed from one end in the axial direction of the heat exchanger.
The gas can easily and reliably flow out to the side.

In the EGR gas cooling device according to the fourth aspect, a plurality of heat radiating plates are stacked at predetermined intervals, an EGR gas passage is formed in the center of the heat radiating plate, and a cooling water pipe is arranged through the heat radiating plate. Since the heat exchanger is configured, the EGR gas that has flowed in from one end in the axial direction of the heat exchanger can easily and reliably flow out to the side.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of an EGR gas cooling device of the present invention.

FIG. 2 is a front view showing the EGR gas cooling device of FIG.

FIG. 3 is an exploded perspective view showing the EGR gas cooling device of FIG.

FIG. 4 is an exploded perspective view showing a method of attaching the EGR gas cooling device of FIG. 1 to an intake manifold.

FIG. 5 is a longitudinal sectional view showing a second embodiment of the EGR gas cooling device of the present invention.

FIG. 6 is an exploded perspective view showing the EGR gas cooling device of FIG.

FIG. 7 is a perspective view showing a distribution pipe that can be arranged in the EGR gas cooling device of FIG. 5;

FIG. 8 is an explanatory view showing a conventional EGR device.

FIG. 9 is a side view showing a conventional EGR gas cooling device.

FIG. 10 is a sectional view showing details of a main part of the EGR gas cooling device of FIG. 9;

[Explanation of symbols]

 21, 51 Heat exchanger 23 Intake manifold 25 Support plate 27, 55 Core part 33 Plate member 35 Cooling water flow path 37 Shell 43, 75 EGR gas passage 47 Heat radiation fin 73 Heat radiation plate 73a Through hole 79 Inflow side pipe 81 Outflow side pipe

Claims (4)

[Claims] 1. An EGR gas cooling device for cooling EGR gas recirculated from an exhaust system to an intake manifold (23) through an EGR pipe line, wherein a coolant is circulated in the intake manifold (23). A heat exchanger (21, 51) for cooling the EGR gas according to (1). 2. The EGR gas cooling device according to claim 1, wherein the heat exchanger (21, 51) has a core part (27, 55).
An EGR gas cooling device characterized in that EGR gas flowing from one end in the axial direction of the EGR gas is caused to flow out laterally. 3. The EGR gas cooling device according to claim 2, wherein said heat exchanger (21) comprises a pair of plate members (33).
Shell (37) in which cooling water flow path (35) is formed
And an EGR gas passage (43) is formed at the center of the shell (37).
A cooling fin (47) for guiding the EGR gas from the center to the side, between the center and the side. 4. The EGR gas cooling device according to claim 2, wherein the heat exchanger (51) has a plurality of heat radiating plates (73) stacked at predetermined intervals and is provided at a center of the heat radiating plates (73). An EGR gas passage (75) is formed, and the cooling water pipe (79, 8) is inserted through the heat radiation plate (73).
An EGR gas cooling device characterized by including the above (1).