JP2011247206A - Exhaust heat recovery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust heat recovery device which can be efficiently assembled in short time.SOLUTION: Both a first outlet 18 and a gas inlet member 23 have a horizontally long rectangle cross section with a length along a valve shaft 67 of a switching valve 32 longer than the length of the valve shaft 67 in a right angle direction. A welding part 42 which connects the first outlet 18 and the gas inlet member 23 is provided on a longitudinal axis 44 of a heat recovery unit 25, and the minimum radius surface 45 of the gas inlet member 23 is formed in curvature to extend near to the longitudinal axis 44 of the heat recovery unit 25. To form the curvature toward the vicinity of the longitudinal axis 44 of the heat recovery unit 25, the welding part 42 is provided obliquely to a detour 16. As the welding part 42 is slanted, a welding torch 65 can easily reach the welding part 42. As the welding torch 65 can easily reach the welding part 42, welding can be done easily, and operation time of the exhaust heat recovery device 10 can be reduced.

Description

  The present invention relates to an exhaust heat recovery apparatus that recovers heat of exhaust gas.

  It is known that exhaust gas generated in an internal combustion engine is sent to a heat recovery device, and cooling water flowing in the heat recovery device is heated by the heat of the exhaust gas (for example, Patent Document 1 (FIGS. 1 and 2). )reference.).

Patent document 1 is demonstrated based on the following figure.
As shown in FIG. 9 (a), the exhaust heat recovery apparatus 100 includes an introduction port 101 through which exhaust gas is introduced, a detour route 102 linearly extending from the introduction port 101, and the detour route 102. A first bent pipe portion 103 that is extended and bent from the vicinity of the inlet 101, a heat recovery device 104 that is connected to the first bent tube portion 103 and recovers the heat of exhaust gas, and a detour 102 from the heat recovery device 104. A second bent pipe portion 105 that extends toward the center, a valve 107 that is provided in the vicinity of the second bent pipe portion 105 and is rotatably supported by a rotary shaft 106 in order to switch the flow path of the exhaust gas, and the valve 107 And a thermoactuator 108 that is connected via a rotating shaft 106 and is operated at the temperature of the cooling water in the heat recovery unit 104.

  When the valve 107 closes the downstream end 109 of the bypass 102, the exhaust gas is flowed to the heat recovery unit 104, and heat exchange is performed with the cooling water in the heat recovery unit 104. The valve 107 opens the downstream end 109 of the detour 102 so that most of the exhaust gas flows through the detour 102.

As shown in (b), the exhaust heat recovery apparatus 100 is assembled by welding a plurality of parts. In general, a welding torch 111 is used for such welding.
By the way, the exhaust heat recovery apparatus 100 has a narrow space between the heat recovery device 104 and the detour 102. Due to the narrowness, a portion where the welding torch 111 is difficult to enter is generated in the vicinity of the first curved pipe portion 103. Since the welding torch 111 is difficult to enter, the welding work takes a lot of time, and the assembly time of the exhaust heat recovery apparatus 100 as a whole becomes long.

  On the other hand, simply widening the space between the heat recovery device 104 and the detour route 102 causes an increase in the size of the exhaust heat recovery device 100, which is not preferable.

  It is desired to provide an exhaust heat recovery apparatus that can be assembled efficiently and in a short time.

JP 2009-209913 A

  An object of the present invention is to provide an exhaust heat recovery apparatus that can be efficiently assembled in a short time.

In the first aspect of the invention, a second outlet is provided downstream of the introduction member through which the exhaust gas flows from the introduction port, and a detour is connected to the second exit so that the second exit is substantially orthogonal to the axis of the introduction port. A first outlet is formed from the introduction member, a junction is branched from the bypass so as to be substantially orthogonal to the axis of the bypass, a gas inflow member is connected to the first outlet, and the gas inflow member is connected to the gas inflow member. A heat recovery unit that recovers the retained heat of the exhaust gas is connected, a gas outflow member is connected to the heat recovery unit, the gas outflow member is connected to the junction, and the flow of the exhaust gas is switched by the switching valve. In the exhaust heat recovery apparatus adapted to switch to the outlet or to the first outlet,
Both the first outlet and the gas inflow member have a horizontally long rectangular cross section in which the length along the valve axis of the switching valve is longer than the length perpendicular to the valve axis, and connects the first outlet and the gas inflow member. A welding part is provided on the longitudinal axis of the heat recovery unit, and the minimum radius surface of the gas inflow member is curved so as to reach the vicinity of the longitudinal axis of the heat recovery unit.

  The invention according to claim 2 is characterized in that the second outlet is linearly connected to the first outlet via a connecting portion in a cross-sectional view, and an angle formed by the connecting portion and the second outlet is an obtuse angle. To do.

  The invention according to claim 3 is characterized in that an angle formed by the connecting portion and the first outlet is an obtuse angle.

  In the first aspect of the invention, the minimum radius surface of the gas inflow member is curved so as to reach the vicinity of the longitudinal axis of the heat recovery unit. In order to curve toward the vicinity of the longitudinal axis of the heat recovery unit, the welded portion is provided obliquely with respect to the detour. Since the welded portion is inclined, the welding torch can easily face the welded portion. Since the welding torch can easily face the welded portion, the welding work can be facilitated, and the working time of the exhaust heat recovery apparatus can be shortened.

  In the invention which concerns on Claim 2, the angle | corner which a connection part and a 2nd exit make is an obtuse angle. The bypass route connected to the second outlet may expand due to heat. It is considered that this expanding force reaches the connecting portion through the second outlet and deforms the connecting portion. It is considered that the amount of deformation of the connecting portion is smaller when the angle between the connecting portion and the second outlet is an obtuse angle than when the angle between the connecting portion and the second outlet is an acute angle. If the amount of deformation is small, the load applied to the connecting portion is also reduced. By reducing the load, the durability of the exhaust heat recovery device can be enhanced.

  In the invention which concerns on Claim 3, the angle | corner which a connection part and a 1st exit make is an obtuse angle. The heat of the detour may be transmitted to the connection part, and the connection part may expand due to the heat. It is considered that this expanding force reaches the gas inflow member through the first outlet and deforms the gas inflow member. The amount of deformation of the gas inflow member is considered to be less when the angle is obtuse than when the angle between the connecting portion and the first outlet is an acute angle. If the amount of deformation is small, the load applied to the first outlet is also small. By reducing the load, the durability of the exhaust heat recovery device can be enhanced.

It is sectional drawing of the waste heat recovery apparatus which concerns on this invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is an enlarged view of part 3 of FIG. 1. 1 is a perspective view of an exhaust heat recovery apparatus according to Embodiment 1. FIG. It is a figure which compares the waste heat recovery apparatus which concerns on this invention, and the conventional waste heat recovery apparatus. FIG. 6 is a sectional view taken along line 6-6 of FIG. It is a figure explaining the waste heat recovery apparatus when the temperature of cooling water rises. It is a schematic diagram explaining the reason which durability improved. It is a figure explaining the basic composition of the conventional technology.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

First, Embodiment 1 of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the exhaust heat recovery apparatus 10 is connected to an introduction member 13 having a flange 12 attached to the outer periphery of an introduction port 11 through which exhaust gas is introduced, and a second outlet 14 of the introduction member 13 and is downstream. A bypass 16 to which the flange 15 is attached at the end, a gas inflow member 23 to which a gas inflow port 22 is connected to a first outlet 18 provided so as to be substantially orthogonal to the axis 17 of the introduction port 11, and the gas inflow member 23 A heat recovery unit 25 supported by a gas outlet 24 provided integrally at the downstream end of the gas, and a downstream side of the heat recovery unit 25 supported by a gas inlet 26 provided integrally. A gas outflow member 29 connected to the merging portion 27 provided on the rotating shaft 31, a rotating shaft 31 that extends in the width direction (the front and back of the drawing) of the introducing member 13 and is rotatably supported, and is supported by the rotating shaft 31 and 1 exit 18 or 2nd A switching valve 32 switches the flow path of the exhaust gas by closing the mouth 14, the switching valve 32 is made of a mesh of the seating portion 33 for seating.

  The switching valve 32 is a V-shaped valve in which a heat recovery path opening / closing part 35 that closes the first outlet 18 and a bypass opening / closing part 36 that closes the second outlet 14 are V-shaped. The V-shaped valve can be provided even in a narrow space as compared with a straight valve, which is beneficial.

  A bent portion 37 that bends the introduction member 13 is provided along the detour opening / closing portion 36 when seated. By making the shape along the detour opening / closing portion 36, the sealing performance when the second outlet 14 is closed is increased.

  A junction 27 is provided in the bypass 16. The junction 27 is provided so as to be substantially orthogonal to the axis 41 of the bypass 16.

  The first outlet 18 closed by the heat recovery path opening / closing part 35 of the switching valve 32 is connected to the gas inflow member 23 by welding. The welded portion 42 that connects the first outlet 18 and the gas inflow member 23 is provided on the longitudinal axis 44 of the heat recovery unit 25.

  The gas inflow member 23 is curved so that the minimum radius surface 45 of the gas inflow member 23 reaches the vicinity of the longitudinal axis 44. By providing the first outlet 18 toward the curved gas inflow member 23, the welded portion 42 is provided on the longitudinal axis 44.

The heat recovery unit 25 whose upstream side is supported by the gas inflow member 23 includes a plurality of (two in this example) heat transfer members 48 in a core case 47.
By passing the exhaust gas through the heat transfer member 48, the heat of the exhaust gas is given to the cooling water passing through the outer periphery of the heat transfer member 48. The cooling water is warmed by the heat of the exhaust gas.

A gas outlet 24 that supports the heat recovery unit 25 is integrally provided in the gas inflow member 23. The number of parts can be reduced by providing them integrally. By providing the gas inlet 26 of the gas outlet member 29 integrally with the gas outlet member 29, the number of parts can be further reduced.
In addition, the number of parts can be reduced by using a split line shape.

  Note that the longitudinal axis 44 of the heat recovery unit 25 is a longitudinal axis. When the longitudinal axis 44 is parallel to the horizontal direction, the welded portion 42 of the gas inflow member 23 may be provided at a height from the lower surface 51 to the upper surface 52 of the core case 47. That is, the longitudinal axis 44 is not limited to the longitudinal axis 44 that passes through the approximate center of the heat recovery unit 25.

  The second outlet 14 to the first outlet 18 are connected by a connecting portion 53. The relationship between the second outlet 14 and the connecting portion 53 and the relationship between the connecting portion 53 and the first outlet 18 will be described in detail in the following drawings.

  As shown in FIG. 2, the connection portion 53 is connected to the second outlet 14 at a predetermined angle θ1. This predetermined angle θ1 is an obtuse angle. That is, the angle formed by the connecting portion 53 and the second outlet 14 is an obtuse angle. When the predetermined angle θ1 is an obtuse angle, the durability of the exhaust heat recovery apparatus 10 can be enhanced. The reason will be described later.

  As shown in FIG. 3, the connection portion 53 is connected to the first outlet 18 at a predetermined angle θ2. This predetermined angle θ2 is an obtuse angle. That is, the angle formed by the connecting portion 53 and the first outlet 18 is an obtuse angle. When the predetermined angle θ2 is an obtuse angle, the durability of the exhaust heat recovery apparatus 10 can be enhanced. The reason will be described later.

  As shown in FIG. 4, a cooling water introduction pipe 56 for guiding cooling water into the core case 47 is connected to the side surface of the core case 47 of the heat recovery unit 25. Similarly, a discharge support member 57 for discharging the cooling water warmed by the core case 47 is provided on the side surface of the core case 47, and the cooling water discharge pipe 58 is extended from the discharge support member 57.

  Furthermore, the discharge support member 57 is connected to a thermoactuator 61 that operates at the temperature of the cooling water. The tip of the rod 62 of the thermoactuator 61 is connected to the urging means 63. The urging means 63 is connected to the rotating shaft (reference numeral 31 in FIG. 1) and urges the rotating shaft.

  By sending the exhaust gas into the exhaust heat recovery apparatus 10, the temperature of the cooling water in the heat recovery unit 25 rises. A part of the cooling water whose temperature has increased flows from the discharge support member 57 toward the thermoactuator 61. The thermo actuator 61 contains wax, and when the temperature of the cooling water exceeds a predetermined temperature, the wax melts and the volume of the wax expands. By expanding, the rod 62 moves forward against the force of the biasing means 63.

  On the other hand, in a state where the rod 62 is moving forward, the temperature of the cooling water may become lower than a predetermined temperature. As the temperature of the cooling water decreases, the wax solidifies and contracts. When contracted, the rod 62 is retracted by the force of the return spring provided in the thermo actuator 61 and urging the rod 62 in the retreating direction and the urging means 63.

As the rod 62 moves forward or backward, the urging means 63 connected to the tip of the rod 62 is rotated. By rotating the urging means 63, both the rotating shaft (FIG. 1, reference numeral 31) connected to the urging means 63 and the switching valve (FIG. 1, reference numeral 32) supported by the rotating shaft are rotated. The flow path of the exhaust gas is switched by rotating the switching valve.
The assembly of the exhaust heat recovery apparatus 10 will be described with reference to the next drawing.

  As shown in FIG. 5A, the introduction member 123 is connected to the gas inflow member 122 by welding the first outlet 121 to the gas inflow member 122. A welding torch 124 may be used for this welding.

  Since the space between the detour path 125 and the gas inflow member 122 is narrow, the exhaust heat recovery apparatus 120 is particularly difficult to weld in the width direction (the front and back direction in the drawing). Since welding is difficult, it takes a long time to manufacture the exhaust heat recovery device 120.

  On the other hand, as shown in (b), the exhaust heat recovery apparatus 10 according to the embodiment is curved so that the minimum radius surface 45 of the gas inflow member 23 reaches the vicinity of the longitudinal axis 44 of the heat recovery unit 25. In order to curve toward the vicinity of the longitudinal axis 44 of the heat recovery unit 25, the welded portion 42 is provided obliquely with respect to the detour route 16. Since the welded portion 42 is inclined, the welding torch 65 can easily face the welded portion 42. Since the welding torch 65 easily faces the welded portion 42, the welding operation can be facilitated, and the working time of the exhaust heat recovery apparatus 10 can be shortened.

  In addition, by forming the gas inflow member 23 in a curved shape, the length of the gas inflow member 23 in the longitudinal direction is shortened by α, and the exhaust heat recovery apparatus 10 can be downsized.

Further, the top 66 of the gas inflow member 23 is set to be approximately the same height as the gas outlet 24 that supports the heat recovery unit 25. By making the height approximately the same as or lower than the gas outlet 24, the exhaust heat recovery apparatus 10 can be mounted in the same space as in the prior art. That is, it is possible to provide the exhaust heat recovery apparatus 10 that can be easily assembled while ensuring the degree of freedom of the mounting position.
The ease of welding will be described in more detail with reference to the following figure.

  As shown in FIG. 6, the first outlet 18 has a length along the valve shaft 67 of the switching valve (FIG. 1, reference numeral 32) in the direction perpendicular to the valve shaft 67 (vertical direction in the drawing). It is set as the horizontally long rectangular cross section longer than this. The gas inlet (FIG. 1, reference numeral 22) of the gas inflow member (FIG. 1, reference numeral 23), which is covered and welded to the first outlet 18, also has a horizontally long rectangular cross section.

  When the welding part 42 is made into welding part 42a, 42b, 42c, 42d for every side, welding of the welding part 42c which must put the welding torch 65 from a detour (FIG. 1, 16) side is especially difficult. there were.

The welding torch 65 is particularly difficult to reach in the vicinity of the central portion 68 of the welded portion 42c having a horizontally long rectangular cross section. As described with reference to FIG. 5, the welding torch 65 is easily exposed to the first outlet 18 having such a horizontally long rectangular cross section.
The durability of the exhaust heat recovery apparatus 10 manufactured in this way will be described with reference to the next figure.

  As shown in FIG. 7, when the cooling water rises to a predetermined temperature, the thermoactuator (FIG. 4, reference numeral 61) operates to rotate the rotating shaft 31 and the switching valve 32. When the switching valve 32 is rotated, the switching valve 32 closes the first outlet 18 and opens the second outlet 14.

By opening the second outlet 14, the exhaust gas flows from the second outlet 14 to the detour 16. Since the exhaust gas is very hot (for example, 700 ° C.), the bypass 16 is expanded by heat. In particular, since the detour 16 has a long length, the detour 16 is greatly expanded as compared with other parts.
On the other hand, when the second outlet 14 is closed and the exhaust gas does not flow, the bypass 16 contracts to the original length.

By repeatedly using the exhaust heat recovery apparatus 10, the detour 16 repeatedly expands and contracts. By repeating the expansion and contraction, the welded portion 69 with the introduction member 13 is particularly affected by the expansion and contraction.
With respect to the influence of such expansion and contraction, it was found that when the angle θ1 formed by the second outlet 14 and the connection portion 53 is an obtuse angle, higher durability can be obtained than when the angle is an acute angle.
The reason why high durability can be obtained will be described with reference to the next figure.

  As shown in FIG. 8A, the first tube 71 and the second tube 72 are connected at an angle θ3 that is an acute angle (an angle smaller than 90 °). The cross section of the second pipe 72 before the exhaust gas flows is circular. In such a state, exhaust gas is allowed to flow through the first pipe 71. The first pipe 71 is expanded by the heat of the exhaust gas.

  As shown in (b), the second tube 72 is tilted by the force that the first tube 71 expands, and the angle θ4 formed by the first tube 71 and the second tube 72 is equal to that in (a). It is considered that the angle is sharper than the angle θ3. At this time, the second tube 72 is deformed to have an elliptical cross section.

  Similarly, as shown in (c), the first tube 73 and the second tube 74 are connected at an angle θ5 that is an obtuse angle (an angle greater than 90 ° and smaller than 180 °). The cross section of the second pipe 74 before the exhaust gas flows is circular. In such a state, exhaust gas is caused to flow through the first pipe 73. The first pipe 73 is expanded by the heat of the exhaust gas.

  As shown in (d), the second tube 74 is erected by the force that the first tube 73 expands, and the angle θ6 formed by the first tube 71 and the second tube 72 is as shown in (c). It is considered that the angle is sharper than the angle θ5. At this time, the second tube 74 is deformed to have an elliptical cross section.

  Comparing the cross sections of (b) and (d), the first pipe 73 and the second pipe 72 are connected in the direction (d) in which the first pipe 73 and the second pipe 74 are connected at an obtuse angle. It is considered that the amount of deformation is smaller than that of (b) connected at an acute angle, and the load applied to the second tube 74 is also considered to be small. It is considered that the durability is enhanced by the small load applied to the second pipe 74.

Returning to FIG. 7 and applying this to the exhaust heat recovery apparatus 10 according to the present invention, it can be considered as follows.
An angle θ1 formed by the connection portion 53 and the second outlet 14 is an obtuse angle. The detour 16 connected to the second outlet 14 may expand due to heat. This expanding force is considered to reach the connecting portion 53 through the second outlet 14 and deform the connecting portion 53. It is considered that the amount of deformation of the connecting portion 53 is smaller when the angle formed by the connecting portion 53 and the second outlet 14 is an obtuse angle than when the angle formed by the connecting portion 53 and the second outlet 14 is an acute angle. If the deformation amount is small, the load applied to the connection portion 53 is also reduced. By reducing the load, the durability of the exhaust heat recovery apparatus 10 can be enhanced.

The following can also be said.
An angle θ2 formed by the connecting portion 53 and the first outlet 18 is an obtuse angle. The heat of the detour route 16 is transmitted to the connection portion 53, and the connection portion 53 may expand due to the heat. It is considered that this expanding force reaches the gas inflow member 23 through the first outlet 18 and deforms the gas inflow member 23. It is considered that the amount of deformation of the gas inflow member 23 is smaller when the angle between the connecting portion 53 and the first outlet 18 is an obtuse angle than when the angle is an acute angle. If the amount of deformation is small, the load applied to the first outlet 18 is also small. By reducing the load, the durability of the exhaust heat recovery apparatus 10 can be enhanced.

The following can also be said.
Compared with the gas outflow member 29 through which the exhaust gas (for example, 90 ° C.) passing through the heat recovery unit 25 and having a low temperature flows, the bypass 16 through which the high-temperature exhaust gas flows has a large elongation due to heat. That is, the temperature of the exhaust gas flowing for each part is different, and the amount of thermal expansion is also different. Different amounts of thermal elongation cause stress. This stress is particularly large near the connection portion 53.

  An angle θ1 formed by the connection portion 53 and the second outlet 14 is an obtuse angle, and an angle θ2 formed by the connection portion 53 and the first outlet 18 is also an obtuse angle. It is considered that the stress is easily dispersed by setting the obtuse angle. Since the stress is easily dispersed, the durability of the exhaust heat recovery device 10 can be enhanced.

  In addition, although this invention was applied to the exhaust-heat recovery apparatus in embodiment, it is applicable also to an EGR (Exhaust Gas Recirculation) cooler, and an application is not limited to these things.

  The exhaust heat recovery device of the present invention is suitable for an exhaust system of a vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Waste heat recovery apparatus, 11 ... Introduction port, 14 ... 2nd exit, 16 ... Detour, 17 ... Axis (of introduction port), 18 ... 1st exit, 23 ... Gas inflow member, 25 ... Heat recovery device, 27 ... Junction part, 29 ... Gas outflow member, 32 ... Switching valve, 41 ... (Detour) axis, 42 ... Welding part, 44 ... Long axis, 45 ... Minimum radius surface, 53 ... Connection part.

Claims (3)

A second outlet is provided downstream of the introduction member through which the exhaust gas flows from the introduction port. A bypass is connected to the second outlet, and the first outlet is connected to the introduction member so as to be substantially orthogonal to the axis of the introduction port. Formed, branching the junction from the bypass so as to be substantially perpendicular to the axis of the bypass, connecting a gas inflow member to the first outlet, and recovering the retained heat of the exhaust gas to the gas inflow member A heat recovery unit is connected, a gas outflow member is connected to the heat recovery unit, the gas outflow member is connected to the junction, and the flow of the exhaust gas is switched to the second outlet or the first outlet by a switching valve. In the exhaust heat recovery device that has been switched,
Both the first outlet and the gas inflow member have a horizontally long rectangular cross section in which the length along the valve axis of the switching valve is longer than the length perpendicular to the valve axis, and connects the first outlet and the gas inflow member. Waste heat is provided on a longitudinal axis of the heat recovery unit, and a minimum radius surface of the gas inflow member is curved so as to reach the vicinity of the longitudinal axis of the heat recovery unit. Recovery device.   2. The second outlet is linearly connected to the first outlet via a connecting portion in a cross-sectional view, and an angle formed by the connecting portion and the second outlet is an obtuse angle. Waste heat recovery equipment.   The exhaust heat recovery apparatus according to claim 2, wherein an angle formed by the connection portion and the first outlet is an obtuse angle.

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