JPH10281015A - Egr gas cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a heat exchanger which serves as a cooler to be easily and certainly arranged in an engine room, in case of an EGR gas cooler for the purpose of cooling EGR gas re-circulated in an intake air manifold via EGR pipe passage from an exhaust system. SOLUTION: In an EGR gas cooler for the purpose of cooling EGR gas re- circulated in an intake air manifold 21 via EGR pipe passage from an exhaust system, an opening part 27 for opening to an EGR gas passage 25 formed in this intake manifold 21 is formed. This opening part 27 is covered freely openably/closably by means of a lid member 29, and in a space part 31 formed inside of the lid member 29, a heat exchanger 33 for cooling EGR gas by circulation of cooling water is arranged, and an inlet pipe 35 and an outlet pipe 37 for the cooling water arranged on the heat exchanger 33 at a specific interval are inserted in through-holes 29b, 29c formed in the lid member 29.

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. 6, an exhaust manifold (or 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. 7 shows a cooling device disposed in this type of EGR device. This cooling device is disposed in a pipe connecting the exhaust manifold and the EGR valve. This cooling device is configured by arranging a large number of pipes 6 in the axial direction of the outer cylinder 5, and as shown in FIG.
Are supported by the end plate 7. On the outer circumference of the outer cylinder 5,
An inlet pipe 8 and an outlet pipe 9 for the cooling water are opened.

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, an opening is formed in the intake manifold to open to an EGR gas passage formed in the intake manifold, and the opening is opened and closed by a lid member, and is formed inside the lid member. A heat exchanger that cools the EGR gas by circulating cooling water is disposed in a space of the cooling water, and an inlet pipe and an outlet pipe of the cooling water that are arranged at predetermined intervals in the heat exchanger are formed in the lid member. Characterized by being inserted through a through hole.

According to a second aspect of the present invention, in the EGR gas cooling apparatus according to the first aspect, the heat exchanger includes a plurality of shells each having a cooling water passage formed between a pair of plate members. A radiating fin through which the EGR gas flows is arranged between the shells, and an inlet pipe and an outlet pipe are erected on the shell on the lid member side.

According to a third aspect of the present invention, there is provided the EGR gas cooling apparatus according to the second aspect, wherein the inlet pipe and the outlet pipe are fixed to the shell via a sheet member, and are provided on an outer end surface of the sheet member. An O-ring to be pressed is disposed on the inner surface of the lid member. An EGR gas cooling device according to a fourth aspect is the EGR gas cooling device according to any one of the first to third aspects, wherein an EGR of a space formed inside the lid member is provided.
The width of the gas passage is substantially equal to the width of the heat exchanger.

(Effect) In the EGR gas cooling device of the first aspect, with the lid member removed from the intake manifold,
A heat exchanger is arranged in the space inside the lid member, and thereafter,
The lid member is attached to the intake manifold such that the inlet pipe and the outlet pipe of the cooling water pass through the through hole of the lid member.

[0013] In the EGR gas cooling device of the second aspect, the EG
While the R gas passes through the radiating fins disposed between the shells, the R gas is exchanged with the cooling water flowing through the cooling water flow path between the pair of plate members via the radiating fins to be cooled.

In the EGR gas cooling device according to the third aspect, an O-ring pressed against the inner surface of the lid member is arranged on the outer end surface of the sheet member to which the inlet pipe and the outlet pipe are fixed. In the EGR gas cooling device according to the fourth aspect, the width of the EGR gas passage in the space formed inside the lid member is made substantially the same as the width of the heat exchanger.

[0015]

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

FIG. 1 shows an embodiment of an EGR gas cooling apparatus according to the present invention, and reference numeral 21 denotes an intake manifold. On the end face of the intake manifold 21,
A flange portion 23 to which a pipe of the EGR gas that has passed through an EGR valve (not shown) is connected is formed. On the upper surface of the intake manifold, a rectangular opening 27 that opens to an EGR gas passage 25 formed in the intake manifold 21 is formed.

The opening 27 is openably and closably covered by a cover member 29. The opening 27 has a female screw portion 21a, and the cover member 29 has a mounting hole 29a. A heat exchanger 33 that cools the EGR gas by circulating cooling water is disposed in a space 31 formed inside the lid member 29. The heat exchanger 33 is mounted on a pair of heat-resistant rubbers 35 arranged at intervals on the bottom surface of the space 31 of the intake manifold 21.

On the upper surface of the heat exchanger 33, a cooling water inlet pipe 35 is provided at intervals in the width direction of the EGR gas passage 25.
And an outlet pipe 37 is provided upright. On the other hand, the cover member 29 is formed with through holes 29b and 29c through which the inlet pipe 35 and the outlet pipe 37 are inserted. FIG.
Shows details of the heat exchanger 33, and the heat exchanger 3
Reference numeral 3 denotes a Dron cup type heat exchanger, which is formed by laminating a plurality of circular shells 41 in which a cooling water flow path is formed between a pair of plate members 39 made of stainless steel.

Each shell 41 has an inlet-side cup portion 43 communicating with the inlet pipe 35 and an outlet-side cup portion 45 communicating with the outlet pipe 37. The radiation fins 47 are arranged between the shells 41. The heat radiation fins 47 are made of, for example, stainless steel, and are formed by forming rectangular corrugated fins without louvers.

The inlet-side cup portion 43 and the outlet-side cup portion 45 of the shell 41 located at the upper end, for example,
A sheet member 49 made of stainless steel is fixed, and an inlet pipe 35 and an outlet pipe 37 are fitted and fixed to the sheet member 49. An annular groove 49a is formed on the outer end surface of the sheet member 49, and the annular groove 49a
An O-ring 51 that is pressed against the inner surface of the lid member 29 is disposed.

In this embodiment, the space 31 of the intake manifold 21 in which the heat exchanger 33 is accommodated is
The width of the EGR gas passage 25 is substantially the same as the width of the heat exchanger 33, and the width direction of the EGR gas passage 25 is formed in a rectangular shape to form a protruding portion 21b. The above-described heat exchanger 33 includes:
In a state where the shell 41 and the radiation fins 47 are alternately laminated and the core is assembled, as shown in FIG. 3, the inlet-side cup 43 and the outlet-side cup 45 of the upper shell 41 are provided.
A small diameter portion 49b formed at the lower portion of the sheet member 49 is fitted therein, and the sheet member 49 is manufactured by, for example, nickel brazing in a state where the inlet pipe 35 and the outlet pipe 37 are fitted.

As shown in FIG. 1, the heat exchanger 33 manufactured as described above has an opening 27 of the intake manifold 21.
With the cover member 29 removed from the cover member 29, the cover member 29 is placed on the heat-resistant rubber 35 in the space 31 inside the cover member 29, and thereafter,
The lid member 29 is connected to the intake manifold 2 with bolts (not shown) so that the inlet pipe 35 and the outlet pipe 37 of the cooling water pass through the through holes 29 b and 29 c of the lid member 29.
Attach to 1.

In the above-described EGR gas cooling device, the EGR gas that has passed through the EGR valve flows into the EGR gas passage 25 from the flange portion 23 of the intake manifold 21, and then passes through the pair of plate members via the radiation fins 47. It is cooled by the cooling water flowing through the cooling water passage between 39, flows out toward the front, and is mixed with the intake air of the intake manifold 21.

Further, cooling water from the engine side flows in from the inlet pipe 35, and cooling water from the outlet pipe 37
The water is discharged upstream of the water pump. In the EGR gas cooling device configured as described above, the intake manifold 2
Opening 2 opening to EGR gas passage 25 formed in 1
7 is openably and closably covered by a cover member 29, a heat exchanger 33 is disposed in a space 31 formed inside the cover member 29, and the inlet pipe 35 and the outlet pipe 37 of the cooling water are covered by the cover member 2.
9, the heat exchanger 33 as a cooling device can be easily and reliably arranged in the engine room.

In the above-described EGR gas cooling device,
A plurality of shells 41 each having a cooling water channel formed between a pair of plate members 39 are stacked, and radiating fins 47 through which EGR gas flows are arranged between the shells 41 to form a heat exchanger 33.
, The heat exchanger 33 can be made small and have high heat exchange efficiency. Further, the above-mentioned EGR
In the gas cooling device, the inlet pipe 35 and the outlet pipe 3
7 is attached to the outer end surface of the sheet member 49 to which the
Since the O-ring 51 pressed against the inner surface of the cover 9 is arranged, the airtightness with the lid member 29 can be easily and reliably improved.

In the above EGR gas cooling device,
Since the width of the EGR gas passage 25 in the space 31 formed inside the lid member 29 is set to be substantially the same as the width of the heat exchanger 33, the EGR from the space between the heat exchanger 33 and the intake manifold 21. The amount of gas leakage can be reduced. Further, in the above-described EGR gas cooling device, since the outer cylinder is not required, the clogging state of the radiating fins 47 is confirmed by removing the lid member 29 from the intake manifold 21 at the time of periodic inspection or the like. Can be easily performed.

Further, in the above-described EGR gas cooling device, the number of stacked shells 41 can be easily changed.
Heat exchange performance, EGR gas resistance, cooling water flow resistance, and the like can be easily changed. In the above-described embodiment, at intervals in the width direction of the EGR gas passage 25,
Although the example in which the cooling water inlet pipe 35 and the outlet pipe 37 are erected has been described, the present invention is not limited to such an embodiment. For example, as shown in FIG.
At intervals in the direction of the GR gas passage 25, the inlet pipe 5
5 and the outlet pipe 57 may be provided upright.

Further, in the above-described embodiment, an example has been described in which the heat exchanger 33 is simply arranged near the inside of the end face of the intake manifold 21. For example, as shown in FIG. A partition wall 59 for guiding the EGR gas passing through the exchanger 33 to the center is formed, and is mixed with the intake air 61 from the turbocharger at the center,
EGR gas may be distributed to each cylinder.

[0029]

As described above, according to the EGR gas cooling system of the first aspect, the EGR gas cooling system is formed in the intake manifold.
Since the opening that opens to the gas passage is openably and closably covered by the lid member, the heat exchanger is arranged in a space formed inside the lid member, and the cooling water inlet pipe and the outlet pipe are inserted through the lid member. The heat exchanger as the cooling device can be easily and reliably arranged in the engine room.

In the EGR gas cooling device of the present invention, a plurality of shells each having a cooling water passage formed between a pair of plate members are stacked, and radiating fins through which the EGR gas flows are arranged between the shells. Since the heat exchanger is configured, the heat exchanger can be small and have high heat exchange efficiency.

In the EGR gas cooling device according to the third aspect, the O-ring pressed against the inner surface of the lid member is disposed on the outer end surface of the sheet member to which the inlet pipe and the outlet pipe are fixed, so that airtightness with the lid member is achieved. Can be easily and reliably improved. In the EGR gas cooling device according to the fourth aspect, the width of the EGR gas passage in the space formed inside the lid member is set to be substantially the same as the width of the heat exchanger. The amount of EGR gas leakage from between can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of an EGR gas cooling device of the present invention.

FIG. 2 is an exploded perspective view showing a heat exchanger of the EGR gas cooling device of FIG.

FIG. 3 is a cross-sectional view showing the vicinity of an insertion part into a lid member in an inlet pipe and an outlet pipe of the heat exchanger of FIG. 1;

FIG. 4 is an explanatory view showing another example of the EGR gas cooling device of the present invention.

FIG. 5 is a perspective view showing still another example of the EGR gas cooling device of the present invention.

FIG. 6 is an explanatory view showing a conventional EGR device.

FIG. 7 is a side view showing a conventional EGR gas cooling device.

FIG. 8 is a sectional view showing details of a main part of the EGR gas cooling device of FIG. 7;

[Explanation of symbols]

 Reference Signs List 21 intake manifold 25 EGR gas passage 27 opening 29 lid member 29b, 29c through hole 31 space portion 33 heat exchanger 35 inlet pipe 37 outlet pipe 39 plate member 41 shell 47 radiating fin 49 sheet member 51 O-ring

Claims (4)

[Claims] 1. An EGR gas cooling device for cooling EGR gas recirculated from an exhaust system to an intake manifold (21) via an EGR pipe, wherein the intake manifold (21) is ), An opening (27) opening to an EGR gas passage (25) is formed, and the opening (27) is openably and closably covered by a lid member (29), and the inside of the lid member (29) is opened. A heat exchanger (3) that cools the EGR gas by circulating cooling water
3), and an inlet pipe (35) and an outlet pipe (37) of the cooling water arranged at predetermined intervals in the heat exchanger (33) are provided with through-holes (37) formed in the lid member (29). 29b, 29c).
GR gas cooling device. 2. The EGR gas cooling device according to claim 1, wherein said heat exchanger (33) comprises a pair of plate members (39).
A plurality of shells (41) in which a cooling water flow path is formed are laminated between the shells (41), and the EG is provided between the shells (41).
A radiating fin (47) through which R gas flows is arranged, and an inlet pipe (3) is provided in the shell (41) on the side of the lid member (29).
5) An EGR gas cooling device characterized by being provided with an outlet pipe (37) and an outlet pipe (37). 3. The EGR gas cooling device according to claim 2, wherein the inlet pipe (35) and the outlet pipe (37)
An O-ring (51) fixed to the shell (41) via a sheet member (49) and pressed against the inner surface of the lid member (29) is arranged on the outer end surface of the sheet member (49). An EGR gas cooling device, characterized in that: 4. The EGR gas cooling device according to claim 1, wherein the space portion (31) formed inside the lid member (29).
Of the EGR gas passage (25) of the heat exchanger (3)
EG characterized in that the width is substantially the same as the width of 3).
R gas cooling device.