JP2014084841A - Exhaust heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized exhaust heat exchanger reduced in cost and improved in vehicle mountability while requiring no piping space.SOLUTION: In an exhaust heat exchanger, a bonnet is formed of a first bonnet plate and a second bonnet plate of two thin plates separated transversely by a vertical split surface. The first bonnet plate is formed with a first incomplete effluent water passage, and the second bonnet plate is also formed with a second incomplete effluent water passage. The individual faces coextensive with the vertical split surfaces of the first bonnet plate and the second bonnet plate are soldered to each other into one bonnet, so that the first incomplete effluent water passage and the second incomplete effluent water passage join to form one complete effluent water passage.

Description

  The present invention relates to an exhaust heat exchanger that performs heat exchange between exhaust gas of an internal combustion engine and cooling water of the internal combustion engine in an EGR (exhaust gas recirculation device).

  Conventionally, as shown in Patent Document 1, for example, when part of exhaust gas discharged from an internal combustion engine is circulated to the intake side of the internal combustion engine in EGR, the exhaust gas is cooled by cooling water of the internal combustion engine. Heat exchangers are known. FIG. 9 is an external view schematically showing the exhaust heat exchanger described in Patent Document 1. FIG.

  In the exhaust heat exchanger 90, the cooling water from the internal combustion engine flows into the main body portion of the outer case from the inflow pipe 91, flows through the main body section (outside the plurality of heat transfer tubes), and then flows out from the outflow pipe 92. Then return to the internal combustion engine. Then, a part of the cooling water in the main body is caused to flow out to the EGR valve 80. In order to prevent water such as the exhaust gas condensed water from freezing in the EGR valve 80 and to prevent the EGR valve 80 from being overheated by the exhaust gas, a part of the cooling water returns to the internal combustion engine after passing through the EGR valve. Further, the exhaust gas discharged from the internal combustion engine flows in from the introduction part 90a, is distributed to each heat transfer tube, flows through each heat transfer pipe, and then gathers and flows out in the lead-out part 90b. At this time, the exhaust gas is cooled by the cooling water in the main body of the outer case. The exhaust gas flowing out from the outlet 90b flows into the EGR valve 80, the flow rate of which is adjusted, flows out of the EGR valve 80, and returns to the intake side of the internal combustion engine.

  The exhaust heat exchanger 90 is formed by accommodating a plurality of stacked flat heat transfer tubes (heat transfer tube group) inside an outer case having a square cross section. An introduction part for introducing exhaust gas is formed on one side in the longitudinal direction of the outer case, and a lead-out part for leading exhaust gas is formed on the other side, and a body part is formed between the introduction part and the lead-out part. Yes.

  Moreover, the pipe expansion part is formed in the both ends of the longitudinal direction of a heat exchanger tube, respectively, when this pipe expansion part is laminated | stacked, it is mutually joined. Furthermore, the outer peripheral part of the whole pipe expansion part joined mutually is joined to the inner wall located in the both ends part of the main-body part of an outer case.

  In the main body of the outer case, an inflow pipe 91 for flowing cooling water into the main body, an outflow pipe 92 for flowing cooling water in the main body to the internal combustion engine side, and a part of the cooling water in the main body. An outflow pipe 93 for flowing out to the EGR valve 80 side is formed. The outflow pipe 93 is connected to the EGR valve 80 through a rubber hose 94.

JP 2010-48536 A

  However, the exhaust heat exchanger requires pipes (cooling water supply pipes) 93 and 94 for supplying cooling water from the exhaust heat exchanger to the EGR valve, and a space for arranging the pipes is necessary. As a result, this piping space becomes a problem in a limited engine room of a vehicle. In addition, since it is necessary to manufacture a cooling water supply pipe separately from the lead-out part, there is a problem that the cost is increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a downsized exhaust heat exchanger with reduced cost, no need for piping space, and improved vehicle mountability. is there.

According to the invention described in claim 1, the exhaust heat exchanger is
Heat exchange is performed between the exhaust gas of the internal combustion engine that flows through the plurality of tubes (21) and the cooling water for cooling the internal combustion engine that flows through the flow path (20a) formed outside the tubes (21). In the exhaust heat exchanger (100),
An exhaust inlet (30);
A main body (20) having a plurality of the tubes (21) stacked in a flat cross section, the flow path (20a), and a water chamber (20b) connected to the flow path (20a). When,
An exhaust outlet (10);
With
The exhaust outlet (10) is formed of a flange (3) and a bonnet (11) made of a thin plate. The bonnet (11) includes a gas passage (10a) and a main body (20). An outflow water channel (10b) that is a passage of cooling water flowing from the water chamber (20b) to the EGR valve (40) is formed,
The bonnet (11) is formed by a first bonnet plate (1) and a second bonnet plate (2) which are two thin plates divided right and left by a vertical dividing surface (XX).
The first bonnet plate (1) is formed with a first incomplete gas passage (1a) and a first incomplete outflow water channel (1b), and the second bonnet plate (2) also has a first bonnet plate (1). Two incomplete gas passages (2a) and a second incomplete outflow channel (2b) are formed,
The first bonnet plate and the second bonnet plate are assembled into one bonnet (1) by brazing the surfaces (1x, 2x) that coincide with the vertical split surfaces (XX) of the first bonnet plate. The complete gas passage (1a) and the second incomplete gas passage (2a) are combined to form one complete gas passage (10a), and the first incomplete effluent channel (1b) and the second The incomplete outflow channel (2b) is combined to form one complete outflow channel (10b).

  A first bonnet plate on which the first incomplete outflow channel is formed and a second bonnet plate on which the second incomplete outflow channel is formed are each manufactured by press molding. Thereafter, the bonnet in which one complete outflow water channel is formed is manufactured by brazing each surface corresponding to the vertical dividing surface of each bonnet plate. As a result, the bonnet can take a form in which an outflow water channel is built in, and the cooling water supply pipe is not disposed outside the bonnet as in the prior art. And since it is not necessary to manufacture a cooling water supply pipe separately from a bonnet, cost is reduced. Furthermore, a piping space is not required, and the mounting property on the vehicle is improved.

  In addition, the code | symbol of said each means shows a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a simplified overview of an exhaust heat exchanger according to the present invention. (A) is a front view, (b) is a top view, and (c) is a BB cross-sectional view. 1 is a front view of an exhaust heat exchanger according to the present invention. It is a top view of the exhaust heat exchanger which concerns on this invention. It is CC sectional drawing of the exhaust heat exchanger which concerns on this invention. It is BB sectional drawing of the exhaust heat exchanger which concerns on this invention. It is AA sectional drawing of the exhaust heat exchanger which concerns on this invention. It is a front view, a top view, a bottom view, a left side view, and a right side view of the first bonnet plate of the exhaust heat exchanger according to the present invention. It is a front view, a top view, a bottom view, a left side view, and a right side view of a second bonnet plate of the exhaust heat exchanger according to the present invention. It is a general-view figure of the exhaust heat exchanger of a prior art example.

(First embodiment)
In the first embodiment, an exhaust heat exchanger according to the present invention is applied to an EGR gas cooler (exhaust heat exchanger) 100 in an exhaust gas recirculation device (EGR) of a diesel engine for a vehicle and a gasoline engine (also referred to as “internal combustion engine”). It is applied. Hereinafter, the configuration of the EGR gas cooler 100 will be described with reference to FIGS.

  The EGR gas cooler 100 is an exhaust heat exchanger that cools exhaust gas recirculated to the engine with engine coolant. As shown in FIG. 1, the EGR gas cooler 100 includes an exhaust inlet portion 30, a main body portion 20, and an exhaust outlet portion 10.

  The main body 20 includes an outer case 22 made of a thin plate, a plurality of tubes (heat transfer tubes) 21 installed inside the outer case 22, and an inlet water pipe 23. The tube 21 is laminated with a flat cross section, and an inner fin 21a is fixed therein. Each member described below is formed from a stainless steel material excellent in strength resistance and corrosion resistance, and the contact portion of each member is joined by brazing (for example, nickel brazing).

  The tube 21 is formed from two tube plates. Each tube plate is formed into a U-shape with a shallow cross section from a flat plate by pressing or roll processing. And the opening side of each tube plate is joined mutually, The tube 21 is formed as an elongate pipe member which has a flat cross section.

  Inside the tube 21 is disposed an inner fin 21a that is pressed from a thin plate material into a cross-sectional wave shape. The inner fin 21 a is joined to the inner surface of the tube 21. The tube 21 having the inner fin 21a is formed by assembling the inner fin 21a so that the inner fin 21a is sandwiched between the two tube plates and then joining them.

  A plurality of tubes 21 are stacked such that the inner surfaces of the tubes on the long side of the flat cross section face each other, and a gas flow path formed inside the tube 21 and a water flow path formed outside the tube 21 20a is formed.

  Here, as shown in FIG. 6, a space is formed between a plurality of stacked tubes 21 (outside of the tube 21), and this space becomes a flow path (water flow path) 20a for cooling water. Yes. A water chamber 20b is provided at the upper and lower portions of the outer case 22, and the flow path 20a is connected to the water chamber 20b. The inlet water pipe 23 is a pipe into which cooling water from the engine flows.

  The exhaust outlet 10 is formed of a flange 3 and a bonnet 11 made of a thin plate. The bonnet 11 is brazed to the outer case 22. Inside the bonnet 11, an EGR gas passage 10 a, an outflow water passage 10 b connecting the water chamber 20 b of the main body 20 and the cooling water passage 40 a in the EGR valve 40 are formed.

  The bonnet 11 includes a thin first bonnet plate 1 and a thin second bonnet plate 2. The 1st bonnet board 1 and the 2nd bonnet board 2 take the form divided | segmented into the right and left by the vertical dividing surface XX of the bonnet 11. As shown in FIG. The first bonnet plate 1 and the second bonnet plate 2 are manufactured by press molding. The first bonnet plate 1 is formed with a first incomplete gas passage 1a and a first incomplete outflow water passage 1b, and the second bonnet plate 2 also has a second incomplete gas passage 2a. And a second incomplete outflow channel 2b is formed. The surfaces 1x and 2x that coincide with the vertical dividing plane XX of the first bonnet plate and the second bonnet plate are brazed together to be assembled into one bonnet 1. As a result, the first incomplete gas passage 1a and the second incomplete gas passage 2a are combined to form one complete gas passage 10a, and the first incomplete outflow water passage 1b and the second incomplete water passage 1a are formed. The complete outflow channel 2b is combined to form one complete outflow channel 10b. By such a manufacturing method of the bonnet 11, it becomes possible to provide an inexpensive bonnet 11 having the outflow water channel 10b.

  As shown in FIG. 1 (particularly (b)), FIG. 5, FIG. 7, and FIG. 8, the bonnet is formed in a funnel shape as a whole. 3 side) is an outer shell body having a circular shape (more specifically, a bowl shape). The side of the bonnet that opens in a square shape is in contact with and joined to the outer periphery of a plurality of stacked tubes 21. The gas passage 10a inside the bonnet communicates with the inside (gas flow path) of a plurality of stacked tubes 21. Further, a flange 3 fastened to the EGR valve is joined to the side of the bonnet that opens in a circular shape (a bowl shape) by brazing.

  In the EGR gas cooler 100 configured as described above, as shown in FIG. 4, a part of the exhaust gas discharged from the engine is gas flow paths in the plurality of tubes 21 of the main body 20 from the exhaust inlet 30. And flows out to the EGR valve 40 through the bonnet 11. The exhaust gas that has flowed out with the flow rate controlled by the EGR valve 40 is again taken into the engine. The EGR valve 40 includes a control motor and a valve (for example, a butterfly valve) connected to the control motor, but the control motor and the valve are omitted in the drawing.

  On the other hand, as shown in FIG. 4, engine cooling water flows through a flow path 20 a formed between a plurality of tubes 21 from an inlet water pipe 23 on the exhaust gas inflow side through an upper water chamber 20 b. Then, it flows out from the outflow water channel 10b again through the water chamber 20b to the EGR valve. A part of the cooling water flowing in from the inlet water pipe 23 once hits the lower water chamber 20b, makes a U-turn again, flows in the flow path 20a, and proceeds to the upper water chamber 20b. At this time, heat exchange is performed between the exhaust gas flowing through the gas flow path and the cooling water flowing through the flow path 20a to cool the exhaust gas.

(Other embodiments)
Further, as shown in FIGS. 1B and 5, each of the complete gas passage 10 a and the complete outflow water passage 10 b is divided into approximately half of the passage cross-sectional area by the vertical dividing plane XX. The bonnet can also be made. And as shown in FIG. 2, FIG. 5, the vertical dividing surface XX can also be set so that the axis line Y of a main-body part may be included.

  As described above, it is possible to provide a downsized exhaust heat exchanger that is reduced in cost, does not require piping space, and has improved vehicle mountability.

DESCRIPTION OF SYMBOLS 1 1st bonnet board 2 2nd bonnet board 3 Flange 10 Exhaust outlet part 11 Bonnet 20 Main body part 20a Water flow path 21 Tube 30 Exhaust inlet part 90 Conventional type EGR gas cooler 100 EGR gas cooler

Claims (3)

Heat exchange is performed between the exhaust gas of the internal combustion engine that flows through the plurality of tubes (21) and the cooling water for cooling the internal combustion engine that flows through the flow path (20a) formed outside the tubes (21). In the exhaust heat exchanger (100),
An exhaust inlet (30);
A main body (20) having a plurality of the tubes (21) stacked in a flat cross section, the flow path (20a), and a water chamber (20b) connected to the flow path (20a). When,
An exhaust outlet (10);
With
The exhaust outlet (10) is formed of a flange (3) and a bonnet (11) made of a thin plate. The bonnet (11) includes a gas passage (10a) and a main body (20). An outflow water channel (10b) that is a passage of cooling water flowing from the water chamber (20b) to the EGR valve (40) is formed,
The bonnet (11) is formed by a first bonnet plate (1) and a second bonnet plate (2) which are two thin plates divided right and left by a vertical dividing surface (XX).
The first bonnet plate (1) is formed with a first incomplete gas passage (1a) and a first incomplete outflow water channel (1b), and the second bonnet plate (2) also has a first bonnet plate (1). Two incomplete gas passages (2a) and a second incomplete outflow channel (2b) are formed,
The first bonnet plate and the second bonnet plate are assembled into one bonnet (1) by brazing the surfaces (1x, 2x) that coincide with the vertical split surfaces (XX) of the first bonnet plate. The complete gas passage (1a) and the second incomplete gas passage (2a) are combined to form one complete gas passage (10a), and the first incomplete effluent channel (1b) and the second An exhaust heat exchanger characterized in that an incomplete outflow channel (2b) is combined to form a complete outflow channel (10b).   The complete one gas passage (10a) and the complete one outflow water passage (10b) are each divided by the vertical dividing surface (XX) into substantially half the passage cross-sectional area. The exhaust heat exchanger according to claim 1.   The exhaust heat exchanger according to claim 1 or 2, wherein the vertical split surface (XX) includes an axis (Y) of the main body (20).

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