JP2012031795A - Waste heat recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste heat recovery system that can reduce noise such as a hammering sound by using a small number of part items.SOLUTION: The waste heat recovery system 10 is composed of: a heat recovery unit 18 which heats cooling water; a heat recovery path 15 which introduces exhaust gas into the heat recovery unit 18; a detour 16 which makes the heat recovery unit 15 make a detour; a switching valve 13 which switches flow passages of the detour 16 and the heat recovery unit 15; and an actuator 35 which operates at a temperature of the cooling water. In a valve 13, a flow-passage closing face 28 for closing an inlet of the detour 16 or an inlet of the heat recovery path 15 is spherical when viewed from a cross section. A pressure difference may be generated between the upstream and downstream of the valve 13. The flow-passage closing face 28 is spherical, and directions of forces are dispersed. The valve 13 is prevented from being opened even if the pressure difference is generated. That is, even if the pressure difference is generated between the upstream and downstream of the valve 13, since the valve 13 is not opened, it is not necessary to attach a collar at the valve 13. Since it is not necessary to attach the collar, the number of part items can be reduced.

Description

  The present invention relates to an exhaust heat recovery apparatus that warms cooling water with the heat of exhaust gas.

  Exhaust gas is generated by operating the internal combustion engine. Heating the cooling water using the heat of the exhaust gas is widely performed. At this time, an exhaust heat recovery device is known in which a bypass is provided separately from the heat recovery path for performing exhaust heat recovery to smoothly exhaust the exhaust gas. Such an exhaust heat recovery apparatus has problems as described in the next figure.

  As shown in FIG. 9A, the exhaust heat recovery apparatus 100 includes a separator 102 provided in an exhaust gas introduction member 101, a rotating shaft 103 provided upstream of the separator 102, and the rotating shaft. A valve 104 that is fixed to 103 and rotates when the rotary shaft 103 rotates, and a seating portion 105 on which the tip of the valve 104 is seated are provided.

  Above the separator 102 is a heat recovery path 107 for recovering the heat of the exhaust gas. On the other hand, below the separator 102 is a bypass 108 for allowing the exhaust gas to escape when heat recovery is not necessary and when the exhaust gas exceeds a predetermined flow rate even during heat recovery.

  A spring that rotates the rotary shaft 103 in a direction to close the bypass circuit 108 is provided outside the introduction member 101. When the valve 104 closes the bypass circuit 108, the exhaust gas flows through the heat recovery path 107.

When the internal combustion engine is operated, exhaust gas generated in the internal combustion engine flows toward the exhaust heat recovery apparatus 100.
By flowing the exhaust gas, the pressure at the point A upstream of the valve 104 may become larger than the pressure at the point B in the bypass 108 on the downstream side of the valve 104. That is, the pressure at point A> the pressure at point B.

Then, as shown in (b), the valve 104 is pushed and the detour 108 is opened.
At a certain moment after the detour circuit 108 is opened, the pressure at the point A is approximately equal to the pressure at the point B, and the valve 104 is connected to the detour circuit 108 by a spring attached to the rotating shaft 103 that is biased toward the seating portion 105 side. It is rotated in the closing direction.

  Further, when the pressure at the point A <the pressure at the point B, as shown in (a), in addition to energizing the valve 104 in the direction in which the rotating shaft 103 closes the detour 108, Pressure indicated by an arrow is applied to the valve 104. The valve 104 closes vigorously by applying a large force in the direction of closing the detour 108. When the valve 104 strikes the seating portion 105 vigorously, noise such as a hitting sound is generated.

  Here, the internal combustion engine repeats intake, compression, combustion, and exhaust. For this reason, below the predetermined number of revolutions, after the tip of the valve 104 hits the seat 105 and makes noise, the exhaust pressure due to the next combustion is applied to the valve 104 and tries to open. By repeating this, the valve 104 strikes the seating portion 105 vigorously, so that noise such as a hitting sound becomes particularly large.

  A technique for reducing such noise has been proposed (see, for example, Patent Document 1 (FIG. 1B)).

Patent document 1 is demonstrated based on the following figure.
As shown in FIG. 10, the exhaust device 200 is attached to a flow path 201 through which exhaust gas flows from the right to the left of the drawing, a valve 202 that closes the downstream end of the flow path 201, and an upper portion of the valve 202. A weight 203 is provided, and a spring 205 is provided so as to surround the rotating shaft 204 and biases the channel 201 in a closing direction.

  According to the exhaust device 200, the weight of the valve 202 is changed by attaching the weight 203 to the valve 202. By changing the weight of the valve 202, the natural frequency is changed and the noise is reduced.

However, such an exhaust device 200 increases the number of parts and the weight by attaching the weight 203.
It is desired to provide an exhaust heat recovery device that can reduce noise with a small number of parts.

Japanese Patent No. 4056227

  An object of the present invention is to provide an exhaust heat recovery apparatus that can reduce noise with a small number of parts.

According to the first aspect of the present invention, a heat recovery unit that warms the cooling water using the heat of the exhaust gas, a heat recovery path that is connected to the heat recovery unit and guides the exhaust gas into the heat recovery unit, and bypasses the heat recovery path. Detours, and a valve that is pivotably provided upstream of these detours and the heat recovery path and switches the exhaust gas flow path by closing the detour or the heat recovery path, and the valve An exhaust heat recovery device comprising a thermoactuator connected to a rotating shaft to be operated and operating when the temperature of the cooling water reaches a predetermined temperature,
The valve is characterized in that at least a part of a flow path closing surface that closes an inlet of a bypass or an inlet of a heat recovery path is a spherical surface in a cross-sectional view.

The invention according to claim 2 is provided with a cover member on the downstream side of the valve along the trajectory of the rotation of the valve,
The cover member is provided with a first opening opened toward the detour and a second opening opened toward the heat recovery path,
The first opening is an entrance to the bypass, and the second opening is an entrance to the heat recovery path.

  The invention according to claim 3 is characterized in that the cover member is integrally provided with an extension portion extended so as to extend the locus from the tip portion on the heat recovery path side.

  According to a fourth aspect of the present invention, when the base is attached to the rotation shaft and the valve closes the detour, the through hole is provided substantially perpendicular to the detour shaft and allows exhaust gas to pass therethrough. It is characterized by comprising a plate-like member having a gap.

  In the invention according to claim 1, the flow path closing surface is a spherical surface in a cross-sectional view. When the valve opens a bypass, a pressure difference may occur upstream and downstream of the valve. Due to this pressure difference, a predetermined force is applied to the flow path closing surface. Since the flow path closing surface is a spherical surface, the direction of the force is dispersed, and at the same time, the force hardly acts in the seating direction of the valve. Therefore, it is possible to prevent the valve from closing vigorously. By preventing the valve from closing violently, the generation of noise such as hammering is suppressed.

  According to the present invention, it is not necessary to adjust the natural frequency of the valve in order to prevent generation of noise by making the flow path closing surface spherical. Since there is no need to adjust the natural frequency, there is no need to attach a weight to the valve. Furthermore, it is possible to improve the seating sound that cannot be removed even if a weight is attached. Since there is no need to attach a weight, the number of parts can be reduced.

  In the invention which concerns on Claim 2, the cover member is provided with the 1st opening part opened toward a detour, and the 2nd opening part opened toward a heat recovery path. The flow path closing surface switches the flow path of the exhaust gas by closing the first opening or the second opening. Compared with the case where all the entrances of the detour path or the heat recovery path are closed, the flow path can be switched reliably without leaking the exhaust gas.

  In the invention which concerns on Claim 3, the cover member is integrally provided with the extension part extended so that a locus | trajectory may be extended from the front-end | tip part by the side of a heat recovery path. An overlift may occur where the thermoactuator operates beyond a predetermined range. The overlift is absorbed by the extension. By absorbing the overlift by the extension portion, it is not necessary to attach a part for absorbing the overlift to the thermoactuator. Space for mounting components is not required, and the thermoactuator can be downsized.

  In the invention which concerns on Claim 4, when the valve | bulb has closed the detour, the plate-shaped member provided substantially perpendicularly with respect to the axis | shaft of a detour is provided. By providing the plate member substantially perpendicular to the axis of the detour, a part of the exhaust gas comes into contact with the plate member. When the flow rate of the exhaust gas exceeds a certain amount, the exhaust gas opens the valve against the force of closing the valve. Regardless of the temperature of the cooling water, exhaust can be efficiently performed by allowing some exhaust gas to escape from the detour when the flow rate is large.

It is sectional drawing of the waste heat recovery apparatus which concerns on this invention. It is a side view of the waste heat recovery device concerning the present invention. 1 is a perspective view of a valve according to Example 1. FIG. It is a side view of a cover member. It is operation | movement explanatory drawing in the state where the temperature of a cooling water is low. It is an effect explanatory view in the state where the temperature of cooling water is high. It is sectional drawing of a thermo actuator. 6 is a cross-sectional view of a valve according to Embodiment 2. FIG. It is a figure explaining the problem of the prior art. It is a figure explaining the basic principle of the prior art.

  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 includes an exhaust gas introduction part 11 into which exhaust gas generated in an internal combustion engine is sent, and a direction perpendicular to the exhaust gas flow direction in the vicinity of the exhaust gas introduction part 11 (drawing). A rotation shaft 12 provided in the front and back direction, a valve 13 supported by the rotation shaft 12, and a cover member 14 provided on a downstream side of the valve 13 and provided along a locus of rotation of the valve 13. A heat recovery path 15, which is one flow path connected to the cover member 14 and switched by the valve 13, a bypass circuit 16 provided to bypass the heat recovery path 15 at a lower portion of the heat recovery path 15, A heat recovery unit 18 that is provided on the upper surface of the detour 16 and heats the cooling water with the heat of the exhaust gas flowing from the heat recovery path 15, and a discharge hole 19 that discharges the exhaust gas that has passed through the heat recovery unit 18 to the detour 16. Tokara .

  The valve 13 includes a spherical main body portion 21 attached to the rotating shaft 12 and a plate-like member 24 provided with a base portion 22 attached to the rotating shaft 12 and provided substantially perpendicular to the shaft 23 of the bypass circuit 16.

The heat recovery unit 18 includes a core case 26 as a main body, and a heat plate 27 provided in the core case 26 and through which exhaust gas flows.
The cooling water that flows in the core case 26 is warmed by the heat of the exhaust gas that flows in the heat plate 27.

  The rotating shaft 12 is urged clockwise by a spring or the like as indicated by an arrow (1). The main body portion 21 closes the detour 16 by the rotation shaft 12 being urged clockwise. That is, the rotating shaft 12 is biased so that the valve 13 closes the bypass circuit 16. At this time, the surface that faces the detour 16 and closes the detour 16 is called a flow path closing surface 28.

The valve 13 is restricted from moving in a direction to close the detour 16 by a stopper 29 provided at a lower portion of the cover member 14.
The valve 13 rotates and closes the heat recovery path 15 when the temperature of the cooling water increases. Details are described in the following figure.

  As shown in FIG. 2, the heat recovery unit 18 includes a cooling water introduction part 32 that introduces cooling water and a cooling water discharge part 33 that discharges the cooling water that has passed through the core case 26. The

The thermoactuator 35 is supported at the base by the cooling water discharge portion 33 and a part of the cooling water discharged from the cooling water discharge portion 33 is sent.
The tip of the rod 36 of the thermoactuator 35 contacts the link member 37 supported by the rotating shaft 12.

  As the temperature of the cooling water rises, the rod 36 of the thermoactuator 35 advances toward the left side of the drawing as shown by the arrow (2). As the rod 36 advances, the link member 37 is rotated counterclockwise as indicated by the arrow (3). The rotating shaft 12 and the valve 13 supported by the link member 37 also rotate counterclockwise, and the valve 13 closes the heat recovery path 15.

When the temperature of the cooling water decreases from the state in which the valve 13 closes the heat recovery path 15, the rod 36 moves backward. As the rod 36 moves backward, the rotating shaft 12 biased in the clockwise direction rotates the valve 13 clockwise. The rotated valve 13 closes the bypass 16. That is, the state is as shown in the figure.
The valve 13 thus rotated will be described in detail with reference to the next figure.

  As shown in FIG. 3, the main body 21 of the valve 13 has a divided spherical shape obtained by dividing a sphere. The plate-like member 24 has a base 22 attached to the rotating shaft 12 and has a semicircular shape along the inner periphery of the main body 21.

  The main body 21 and the plate-like member 24 may be a combination of a divided columnar shape and a rectangular shape in addition to the divided spherical shape and semicircular shape shown in the drawing. That is, when the cross section is perpendicular to the rotation shaft 12, the flow path closing surface 28 of the main body 21 may be a spherical surface. Moreover, the plate-shaped member 24 should just be a shape in alignment with the inner periphery of the main-body part 21. FIG.

  The plate-like member 24 is provided with a plurality of differently shaped through holes 39a to 39c through which exhaust gas passes. The larger the sum of the areas of these through holes 39a to 39c, the better the passage of exhaust gas. By improving the flow of the exhaust gas, even when the flow rate of the exhaust gas increases, the exhaust gas can smoothly flow to the heat recovery path.

On the other hand, the smaller the total area of the through holes 39, the greater the amount of exhaust gas that contacts the plate member 24. By increasing the amount of exhaust gas in contact with the plate member 24, the valve 13 is easily rotated.
A cover member for covering such a valve 13 will be described with reference to the next drawing.

  As shown in FIG. 4, the cover member 14 is provided with a first opening 41 that opens toward the detour (FIG. 1, reference numeral 16), and opens toward the heat recovery path (FIG. 1, reference numeral 15). The second opening 42 is provided.

  When the valve 13a (a is a subscript indicating that the valve is in a position to close the first opening 41; the same applies hereinafter) closes the first opening 41, the exhaust gas is heated from the second opening 42. It flows into the collection path.

On the other hand, the valve 13b (b is a subscript indicating that the valve is in a position to close the second opening 42; the same shall apply hereinafter) closes the second opening 42, so that the exhaust gas is supplied to the first opening 41. To the detour.
That is, the first opening 41 is an entrance to the detour, and the second opening 42 is an entrance to the heat recovery path.

  By the way, the valves 13a and 13b rotate within a range indicated by an imaginary line to switch the exhaust gas flow path. For this reason, the cover member 14 that covers the valves 13a and 13b may be provided in the section from P1 to P2. Of the cover member 14, P1 to P2 are referred to as a base portion 44.

On the other hand, when the temperature of the cooling water exceeds a predetermined temperature, the valve 13b may move further from P2 toward P3. In order to absorb the excessive movement of the valve 13b, the cover member 14 is desirably provided up to P3. That is, P2 to P3 are referred to as an extended portion 45 extended from the base portion 44.
That is, the cover member 14 is integrally provided with an extended portion 45 that extends from the distal end portion P2 of the base portion 44 along the locus of the valve 13b.

  The flow path closing surface 28 switches the flow path of the exhaust gas by closing the first opening 41 or the second opening 42. Compared with the case where all the entrances of the detour path or the heat recovery path are closed, the flow path can be switched reliably without leaking the exhaust gas. It is desirable that the flow path can be reliably switched with a simple configuration.

Particularly in the present invention, the cross section of the flow path closing surface 28 is a spherical surface. In order to reliably close the flow path with the spherical flow path closing surface 28, it is desirable to provide the cover member 14 having a shape along the locus of the valves 13a and 13b.
The operation of the exhaust heat recovery device will be described in detail in the following figures.

  As shown in FIG. 5A, when the temperature of the cooling water is as low as T1, the valve 13 closes the bypass 16. By closing the bypass 16, the exhaust gas passes through the heat recovery path 15, and heat exchange with the cooling water is performed by the heat recovery unit 18 to warm the cooling water. The exhaust gas that has passed through the heat recovery unit 18 is discharged to the outside through the discharge hole 19.

  When the valve 13 closes the bypass 16, the exhaust gas flow rate may increase instantaneously. As shown in (b), a part of the exhaust gas contacts the plate member 24. When the flow rate of the exhaust gas exceeds a certain amount, the exhaust gas in contact with the plate-like member 24 (see the white arrow (4)) opens the valve 13 against the force to close the valve 13. By opening the valve 13, the exhaust gas can escape to the detour 16 as indicated by the white arrow (5).

  After the exhaust gas has escaped to the bypass route 16, the pressure upstream of the valve 13 may be substantially equal to the pressure downstream of the valve 13. Since the flow path closing surface 28 is a spherical surface, the direction of force is dispersed as indicated by the white arrows (6) and (6). That is, it is possible to prevent pressure from being applied in the direction in which the valve 13 is closed. Generation of noise is suppressed by dispersing the direction of the force and preventing the valve 13 from closing forcefully.

  According to the present invention, since the generation of noise is prevented by making the flow path closing surface 28 a spherical surface, it is not necessary to adjust the natural frequency of the valve 13. Since there is no need to adjust the natural frequency, there is no need to attach a weight to the valve 13. Furthermore, it is possible to improve seating sound that cannot be removed even if a weight is attached. Since there is no need to attach a weight, the number of parts can be reduced.

  In addition, a part of the exhaust gas is allowed to escape from the bypass 16 when the flow rate of the exhaust gas is large regardless of the temperature of the cooling water. By bypassing the heat recovery path 15 having a high flow path resistance, exhaust can be efficiently performed.

Furthermore, by adjusting the total area of the through holes 39, the flow rate of the exhaust gas when the valve 13 is opened can be adjusted. That is, if the total area of the through holes 39 is large, the valve 13 is difficult to open, and if the total area of the through holes 39 is small, the valve 13 is easy to open. Adjustment can be performed simply by providing the through hole 39, and the labor required for adjustment can be reduced.
By continuing to warm the cooling water, the temperature of the cooling water rises to a predetermined temperature. The operation when the cooling water rises to a predetermined temperature will be described with reference to the next figure.

  As shown in FIG. 6A, when the temperature of the cooling water rises to a predetermined temperature T2, the valve 13 closes the heat recovery path 15 and stops heat exchange. The exhaust gas flows through the bypass 16.

  By the way, the temperature of the cooling water may rise higher than the highest temperature T2 that is initially assumed. When the temperature rises to a temperature T3 higher than T2, the rod (36 in FIG. 2) of the thermoactuator may advance beyond a predetermined range.

  As shown in (b), when an overlift occurs in which the rod of the thermoactuator moves forward beyond a predetermined range, the extension 45 absorbs the excessive movement of the valve 13. By absorbing the overlift by the extension portion 45, it is possible to obtain an effect as described in the next figure.

  As shown in FIG. 7A, the thermoactuator 300 according to the comparative example includes a case 303 in which a cooling water introduction unit 301 and a cooling water discharge unit 302 are provided and wax is stored therein, and the case 303 stores therein. A piston 304 that is actuated by wax, a rod 306 disposed at the tip of the piston 304 via an absorption spring 305, a lid 307 that houses a part of the rod 306 and is connected to the case 303, A return spring 308 is housed in the lid 307 and returns the rod 306 when the wax contracts.

  The thermoactuator 300 according to the comparative example is provided with an absorption spring 305 to absorb overlift.

  On the other hand, the thermoactuator 35 according to the embodiment shown in (b) absorbs the overlift by the extension part (FIG. 1, sign extension part 45) provided in the cover member (FIG. 1, sign cover member 14). . For this reason, it is not necessary to use an absorption spring for the thermoactuator 35. The thermoactuator 35 can be reduced in size by α because the absorption spring is not disposed.

Next, a second embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 8, the valve 50 forms a V-shaped support member 54 by extending the extension support portion 53 so as to be bent from the base portion 52 of the plate-like member 51. The main body 58 provided with the flow path closing surface 57 is attached to the support shaft 54.

  61 and 62 are through holes for allowing exhaust gas to pass therethrough. The through hole is provided in both the plate-like member 51 and the extended support portion 53.

  Even when such a valve 50 is used, the flow path closing surface 57 is a spherical surface in a sectional view, and the direction of the force is dispersed. The valve 50 is prevented from closing vigorously and noise such as hitting is prevented. Since it is not necessary to attach a weight to prevent the generation of noise, the number of parts can be reduced.

  In addition, since the main body 58 is attached to the V-shaped support member 54, the assembly work of the valve 50 is easy.

  The exhaust heat recovery apparatus according to the present invention can be applied not only to an exhaust heat recovery device but also to an EGR (Exhaust Gas Recirculation) cooler or the like, and may be applied to other uses.

  The exhaust heat recovery apparatus of the present invention is suitable for a hybrid vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Waste heat recovery apparatus, 12, 55 ... Turning shaft, 13, 50 ... Valve, 14 ... Cover member, 15 ... Heat recovery path, 16 ... Detour, 18 ... Heat recovery device, 22, 52 ... Base, 23 ... (bypass) shaft, 24, 51 ... plate-like member, 28 ... flow path closing surface, 35 ... thermoactuator, 39 ... through hole, 41 ... first opening, 42 ... second opening, 45 ... extension Department.

Claims (4)

A heat recovery unit that heats the cooling water with the heat of the exhaust gas, a heat recovery path that is connected to the heat recovery unit and guides the exhaust gas into the heat recovery unit, and a detour that is provided to bypass the heat recovery path A valve that is rotatably provided upstream of the bypass and the heat recovery path and that switches the exhaust gas flow path by closing the bypass or the heat recovery path, and a rotary shaft that rotates the valve. An exhaust heat recovery device comprising a thermoactuator connected to the thermoactuator and operating when the temperature of the cooling water reaches a predetermined temperature,
The exhaust heat recovery apparatus according to claim 1, wherein a flow path closing surface that closes the inlet of the bypass or the inlet of the heat recovery path is a spherical surface in a sectional view. A cover member is provided on the downstream side of the valve along the locus of rotation of the valve,
The cover member includes a first opening that opens toward the detour and a second opening that opens toward the heat recovery path,
The exhaust heat recovery apparatus according to claim 1, wherein the first opening is an inlet of the bypass and the second opening is an inlet of the heat recovery path.   The exhaust heat recovery apparatus according to claim 2, wherein the cover member is integrally provided with an extension portion extending so as to extend the locus from the tip portion on the heat recovery path side.   When the base is attached to the rotating shaft and the valve closes the bypass, the base is provided substantially perpendicular to the shaft of the bypass, and a through hole for passing the exhaust gas is formed. The exhaust heat recovery apparatus according to claim 1, further comprising a plate-like member.

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