JP2000265834A - Heat exchanger for recovering exhaust gas heat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover the waste heat of an internal combustion engine while muffling the exhaust gas noise by applying a heat exchanger to be formed of a plurality of plates to a heat exchanger for recovering the exhaust gas heat. SOLUTION: This heat exchanger for recovering the exhaust gas heat is arranged in a muffler to reduce the noise of the exhaust gas from an engine for running a vehicle. A plurality of fins 130 to promote the heat exchange of cooling water with the exhaust gas are joined with surfaces of plates 111, 112, the fins 130 have a plurality of bent portions 131, and extended to bridge a through hole 121. In addition, a clearance 140 is provided between the fins so that the exhaust gas is distributed toward a space (a resonance chamber) located outside the plates 111-113 from the through hole 121. Since a part of the exhaust gas to be distributed in an exhaust gas passage 120 is passed through the clearance 140 and flows into the space (resonance chamber), the waste heat can be recovered while muffling the exhaust gas noise of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for recovering exhaust heat, which is disposed in a muffler for reducing noise generated by exhaust gas discharged from an internal combustion engine and recovers waste heat of the exhaust gas. This is effective when applied to vehicles.

[0002]

2. Description of the Related Art As a heat exchanger for recovering exhaust heat, for example, in the invention described in JP-A-59-65513, a fluid such as cooling water is circulated around a plurality of thin tubes through which exhaust gas flows. A heat exchange unit is configured to recover waste heat of exhaust gas.

[0003]

However, in the above configuration, it is necessary to assemble and join a plurality of thin tubes.
The structure of the heat exchange unit becomes complicated, which may increase the number of assembling steps. In addition, since the exhaust gas is circulated inside the simple round pipe and the fluid is circulated outside the simple round pipe, the temperature boundary layer easily grows and the heat transfer coefficient decreases,
There is a problem that heat exchange efficiency (heat recovery capacity) is low.

On the other hand, a drone cup type heat exchanger (in which a plurality of plates are laminated to form a tube or a tank) used in an air-cooled oil cooler or an evaporator for a vehicle, It has been technically established as a small size, high productivity and high heat exchange rate. Then, the inventors and others studied to apply this drone cup type heat exchanger to a heat exchanger for exhaust heat recovery, and found the following problems.

[0005] That is, when a Drone cup type heat exchanger (hereinafter abbreviated as a heat exchanger) is applied to an exhaust heat recovery heat exchanger, the exhaust gas is substantially perpendicular to the core of the heat exchanger. However, if the exhaust heat recovery heat exchanger is simply disposed in the muffler as described above, a part of the exhaust gas is formed outside the exhaust heat recovery heat exchanger such as a resonance chamber. The exhaust cannot be exhausted into the space, and the exhaust cannot be silenced.

On the other hand, in a normal heat exchanger, a part of exhaust gas cannot be discharged to a space formed outside the heat exchanger during a process of passing through the core portion. The present invention
In view of the above, it is an object of the present invention to apply a heat exchanger configured by stacking a plurality of plates to an exhaust heat recovery heat exchanger.

[0007]

According to the present invention, in order to achieve the above object, the present invention is characterized in that a fluid passage extending in a direction intersecting a flow direction of exhaust gas and flowing a fluid is provided. 110), a plurality of plates (111,
112) and the plate surfaces (11, 112) of the plates (111, 112).
1a, 112a) and has a plurality of fins (130) for promoting heat exchange between the exhaust and the fluid, and the exhaust flows through the plates (111, 112) in the thickness direction thereof. An exhaust hole (121) is formed, and a gap (140) through which exhaust gas can flow from the exhaust hole (121) to the outside of the plates (111, 112) is formed between the plurality of fins (130). It is characterized by being provided.

As a result, a part of the exhaust gas flowing through the exhaust hole (121) is allowed to flow through the gap (140) to allow the plate (1) to flow.
11, 112), so that waste heat can be recovered while silencing the exhaust of the internal combustion engine.
Therefore, the heat exchanger of the Dron cup type (a stack of a plurality of plates) can be applied to the heat exchanger for waste heat recovery, so that the size of the heat exchanger for waste heat recovery can be reduced while improving productivity. And the heat exchange rate (heat recovery capacity) can be improved.

According to the second aspect of the present invention, the fin (13)
0) extends over the exhaust hole (121) to extend the plate surface (1).
11a, 112a). Thus, the fins (130) can be directly exposed to the exhaust gas, so that the heat exchange rate (heat recovery capacity) can be further improved. The exhaust hole (121) may be formed substantially at the center of the plate (111, 112).

[0010] Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, an exhaust heat recovery heat exchanger (hereinafter, referred to as an exhaust heat recovery heat exchanger) 100 according to the present invention is applied to a vehicle, and FIG. FIG. 3 is a state diagram showing a state in which an exhaust heat recovery heat exchanger 100 is provided in a muffler 200 that reduces noise generated by exhaust gas discharged from a vehicle traveling engine (not shown).

In this embodiment, the muffler 200 is of a resonance type, and a space 210 inside the muffler 200 outside the exhaust heat recovery heat exchanger 100 constitutes a resonance chamber for reducing noise. . Next, the structure of the exhaust heat recovery heat exchanger 100 will be described. FIG. 2 is a cross-sectional view of the exhaust heat recovery heat exchanger 100 cut in the exhaust gas flow direction.
Reference numeral 10 denotes a cold water passage (fluid passage) through which cooling water (fluid) for collecting waste heat flows, and reference numeral 120 denotes an exhaust passage through which exhaust gas flows.

The cold water passage 120 is formed by laminating stainless steel plates 111 to 113, each of which has a predetermined shape by press working, in the flow direction of exhaust gas, and then welds the plurality of plates 111 to 113. It is formed by this. On the other hand, the exhaust passage 120 is formed by forming a through hole (exhaust hole) 121 that penetrates in the thickness direction at substantially the center of each of the plates 111 to 113. For this reason, the exhaust passage 120 is
It is configured to extend in the stacking direction of 1 to 113.

The plate surfaces 11 of the plates 111 and 112
A plurality of fins 130 for promoting heat exchange between the cooling water and the exhaust are joined to each of the fins 1a and 112a.
31 are corrugated fins formed so that the ridge direction D (see FIG. 4) connecting the tops of the bent portions 131 is orthogonal to the plate surfaces 111a and 112a.

Incidentally, since the plate surfaces 111a and 112a extend in a direction perpendicular to the exhaust gas flow direction, the ridge direction D connecting the tops of the bent portions 131 is parallel to the exhaust gas flow direction. In the present embodiment, the cold water passage 11
0 is three steps in the direction of exhaust gas flow as shown in FIG. 2, but in FIG. 4, the second step and subsequent steps are omitted to be one step due to space limitations.

3 and 4, the fins 130 are provided so as to extend (straddle) the through holes 121, and between the fins 130, the through holes 121 are provided. (Exhaust passage 130) from each plate 1
A gap 140 is provided so that the exhaust gas can flow toward a space (resonance chamber) 210 located outside of 11 to 113.

The fin 130 has a window-shaped louver (not shown) that disturbs the exhaust flow in order to prevent the temperature boundary layer generated at the end of the fin 130 from growing large.
Are formed. By the way, as shown in FIGS. 2 and 4, the introduction pipe 11 for guiding the cooling water to the cold water passage 110 is provided on the plate 111 on the side of the inlet 122 of the exhaust passage 120.
4, and an outflow pipe 115 through which the cooling water having undergone the recovery of waste heat flows out is joined.
Is connected to a cooling water circuit of the engine via an external pipe (not shown).

The exhaust passage 120 has an inlet 122 side,
Each of the plates 111 and 113 located at the outlet 123 has an inlet-side exhaust pipe 22 joined to the muffler 200.
0 or the outlet side exhaust pipe 230 and the exhaust heat recovery heat exchanger 10
0 (exhaust passage 120), a collector side joint plate (joint flange) 151, 15
2 are welded.

Similarly, both exhaust pipes 220 and 230 have an exhaust pipe side joint plate (joint flange) 22.
1, 231 are welded, and both joint plates 1
51, 152, 221 and 231 are connected by bolts (not shown) via metal gaskets (packings) 153 and 154. The outlet side exhaust pipe 23
0, the outlet side exhaust pipe 230 as shown in FIG.
A hole 232 is provided for discharging a part of the exhaust flowing through the inside toward the space (resonance chamber) 210.

Next, the features of this embodiment will be described. A gap 140 is provided between each fin 130 so that exhaust gas can flow from the through hole 121 (exhaust passage 130) to a space (resonance chamber) 210 located outside each of the plates 111 to 113. Therefore, a part of the exhaust gas flowing through the exhaust passage 120 can flow through the gap 140 and flow into the space (resonance chamber) 210, and the exhaust heat of the engine can be muffled and the waste heat can be recovered.

Accordingly, a heat exchanger of the Dron cup type (a stack of a plurality of plates) can be applied to the heat exchanger for exhaust heat recovery 100, so that the heat exchanger for exhaust heat recovery 100 can be reduced in size. It is possible to improve the productivity and the heat exchange rate (heat recovery capacity) while aiming. Also, so that the fins 130 bridge the through-holes 121 (to straddle them).
Since the fins 130 are extended,
20 can be directly exposed to the exhaust gas flowing therethrough, so that the heat exchange rate (heat recovery capacity) can be further improved.

In the above-described embodiment, the present invention is applied to a vehicle, but the present invention is not limited to this. The present invention is applied to a heat exchanger for exhaust heat recovery of a stationary engine such as a generator. Can also be applied. Also, fin 1
The fin 30 is not limited to corrugated fins, but may be other fins such as offset fins in which the phases of rectangular fins are shifted.

In the above embodiment, each plate 1
Although 11 to 113 are welded, the plates 111 to 113 may be joined by other joining means such as brazing. Further, in the above and the embodiments, the resonance type is also an internal combustion engine having a muffler, but may be other types of muffler such as an interference type, an expansion type and a sound absorbing type.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a muffler having a built-in heat exchanger for exhaust heat recovery, and FIG. 1B is a view taken in the direction of arrow A in FIG.

FIG. 2 is a sectional view of a heat exchanger for exhaust heat recovery.

FIG. 3 is a front view of the exhaust heat recovery heat exchanger viewed from a direction in which exhaust gas flows.

FIG. 4 is an exploded perspective view of the exhaust heat recovery heat exchanger.

[Explanation of symbols]

100 heat exchanger for exhaust heat recovery, 110 cold water passage (fluid passage), 111-113 plate, 120 exhaust passage, 121 (through hole) exhaust hole, 130 fin, 14
0 ... gap.

Claims (3)

[Claims] 1. A heat exchanger for exhaust heat recovery disposed in a muffler (200) for reducing noise generated by exhaust gas discharged from an internal combustion engine and recovering waste heat of the exhaust gas, A plurality of plates (111, 112) extending in a direction intersecting the flow direction and forming a fluid passage (110) through which fluid flows, and plate surfaces (111a, 1) of the plates (111, 112);
12a), a plurality of fins (130) for promoting heat exchange between the exhaust gas and the fluid, and the exhaust gas penetrates through the plates (111, 112) in the thickness direction thereof. An exhaust hole (121) that circulates is formed. Further, between the plurality of fins (130), the exhaust gas may flow from the exhaust hole (121) to the outside of the plates (111, 112). Possible gap (14
(0) is provided. 2. The fin (130) has a plurality of bent portions (131) and the bent portions (13).
The ridge direction (D) connecting the tops of 1) is the plate surface (111).
a, 112a) are corrugated fins formed so as to be orthogonal to the exhaust holes (12).
1) to extend over the plate surface (111a, 112
The exhaust heat recovery heat exchanger according to claim 1, wherein the heat exchanger is provided in a). 3. The heat exchanger for exhaust heat recovery according to claim 1, wherein the exhaust hole (121) is formed substantially at the center of the plate (111, 112).