DE102013107868A1 - Exhaust heat recovery device - Google Patents

Abstract

An exhaust heat recovery device includes: an inner pipe portion in which a coolant flows; an intermediate pipe section disposed outside the inner pipe section at a predetermined distance therefrom to form a heat recovery duct between the intermediate pipe section and the inner pipe section for recovering heat of the introduced exhaust gas into the coolant; an outer pipe portion disposed outside the intermediate pipe portion at a predetermined distance therefrom to form a bypass passage between the outer pipe portion and the intermediate pipe portion so that the bypassed exhaust gas flows into the bypass passage; and an exhaust valve at an upstream end in the flow direction of the exhaust gas within the intermediate pipe section to switch the flow of the exhaust gas between the heat recovery duct and the bypass duct.

Description

Background of the invention

Field of the invention

The present invention relates to an exhaust heat recovery device that recovers exhaust heat of an engine into a coolant, such as engine cooling water.

Description of the Prior Art

In the prior art, an exhaust heat recovery apparatus is known which recovers exhaust heat of an internal combustion engine of a motor vehicle (for example, an automobile engine, which will be simply referred to as an engine hereinafter). This exhaust heat recovery device is located in an intermediate region of an engine exhaust pipe to perform heat exchange between exhaust gas (exhaust gas) coming out of the engine and flowing through the exhaust pipe and the cooling water of the engine. For example, the exhaust gas heat recovered via the cooling water of the engine is used to rapidly raise the temperature of the cooling water when the engine is still cold, for example, serving the purpose of achieving a rapid warm-up of the engine, and the exhaust heat is used to heat the engine Driver's cab used.

Exhaust heat recovery devices currently in use can be broadly divided into two types of a first conventional technique (as disclosed in US Pat 5 shown), disclosed in the patent document 1 ( Japanese Patent Laid-Open Publication No. 2010-31671 ), and a second conventional technique (not shown here) as shown in Patent Document 2 ( Japanese Patent Laid-Open Publication No. 2001-30741 ). Of these two techniques, the first conventional technique is predominant in terms of cost and the like.

An exhaust heat recovery unit 100 ( 5 ) of the first conventional technique includes an inner pipe section 101 containing a bypass channel (or flow path) 104 forms for the passage of the exhaust gas, an exhaust valve 102 which is the bypass channel 104 on a downstream side of the inner pipe section 101 opens and closes, an outer pipe section 103 located on the outer peripheral side of the inner pipe section 102 is provided at intervals, and a heat exchange section (exhaust heat recovery channels or paths 105 and 106 , and cooling water channels or flow paths 107 and 108 ), between the inner pipe section 101 and the outer tube section 103 ,

To recover exhaust heat, the exhaust valve 102 closed, and that in the inner tube section 101 introduced exhaust gas passes sequentially in a first exhaust heat recovery channel 105 and a second exhaust heat recovery channel 106 located on the outer peripheral side of the inner pipe section 101 located over a large number of small holes 109 located in a side area of the inner pipe section 101 are formed, so that the heat exchange between the exhaust gas and the cooling water takes place, which through the inner cooling water channel 107 and the outer cooling water channel 108 flows.

As the main purpose of the exhaust heat recovery unit 100 is to warm the engine after its start, and to heat the vehicle interior, as explained above, the exhaust gas is then discharged (removed) when the need for warming up or heating after a certain period of time following the start of the engine has become smaller is.

When discharging the exhaust heat, the valve 102 closed, and that in the inner pipe section 101 introduced exhaust gas is discharged directly to the downstream side, so that the exhaust gas not first through the first heat recovery channel 105 and the second heat recovery channel 106 arrives. As a result, an unnecessary increase in the temperature of the cooling water is suppressed, while a pressure loss of the exhaust gas is prevented.

On the other hand, in the exhaust heat recovery apparatus (heat storage system for vehicles) of the second conventional art, there is provided a cooling water system of an engine including a heat recovery unit and a heat accumulator. The heat recovery unit is disposed along one of two sections branched from an exhaust system of the engine so that the heat exchange between exhaust gas discharged from the engine and cooling water of the engine is executable.

However, in the conventional techniques, there is still a need for the possibility of designing the exhaust heat recovery device to continuously recover the exhaust heat while the engine is running in normal operation and also in high load operation after the exhaust heat recovery device has its purpose warming up the engine or heating the cab so that improved fuel economy is possible. This requirement applies, for example, to a vehicle that is equipped with a Rankine process system in which exhaust gas heat is constantly supplied to the cooling water and the heat recovered as Heat source of a Rankine process heater is used.

However, when an attempt is made to recover the exhaust heat during normal operation of the engine in the first and second conventional techniques, the following problems arise:
First, the cooling water cooled by airflow is accompanied by a deteriorated efficiency of heat recovery.

That is, in a vehicle having the engine in the front region, an exhaust pipe extends from the front of the vehicle to the rear side thereof via the underbody side, thus the exhaust heat recovery unit is located 100 on the bottom of the floor. However, since the cooling water near the outer pipe section 103 within the exhaust heat recovery unit 100 flows during normal operation and also in high-speed operation of the engine generated strong air wind tends to cool the cooling water, which has absorbed the exhaust heat in itself. As a result, there is a heat loss, which leads to a deterioration of the recovery efficiency of the exhaust heat. This undesirable condition also comes about in connection with the second conventional technique, which is disadvantageous.

Second, the exhaust and cooling water suffer a heavy pressure loss.

That is, on the exhaust side of the exhaust heat recovery unit 100 the exhaust gas flows over the small holes 109 to the first exhaust heat recovery channel 105 and then the exhaust gas flows in the reverse direction between the upstream side and then flows to the second exhaust heat recovery channel, resulting in a considerable pressure loss. As a result, there is a deterioration in the output and, in the high-load operation of the engine, there is a deterioration of the fuel efficiency in particular. In addition, because on the side of the cooling water, the inner cooling water channel 107 and the outer cooling water channel 108 have a small cross-section, the cooling water is exposed to a strong pressure loss with high water pump performance, which in turn leads to the problem of deteriorated fuel economy. Such deterioration also occurs in the second conventional technique, which is disadvantageous.

Even if the exhaust heat recovery apparatus is of the type in which the exhaust heat is continuously recovered in the normal operation of the engine, there is still a demand for the exhaust heat recovery apparatus to easily control a recovery amount of exhaust heat as a request from a Rankine process system or the like.

DISCLOSURE OF THE INVENTION

The present invention has been made in view of the above-described circumstances of the conventional techniques, and it is an object of the invention to provide an exhaust heat recovery apparatus capable of decreasing the amount of recovery heat due to the influence of wind avoid reducing a pressure loss in the exhaust gas and the refrigerant involved in the heat exchange, and also being able to easily control the amount of recovery heat.

These and other objects can be attained according to the present invention by providing an exhaust heat recovery apparatus including: an inner pipe section in which a coolant flows; an intermediate pipe portion disposed outside the inner pipe portion at a predetermined interval to form a heat recovery passage between the intermediate pipe portion and the inner pipe portion for recovering heat of the introduced exhaust gas into the coolant; an outer pipe section disposed outside the intermediate pipe section at a predetermined distance therefrom to form a bypass passage between the outer pipe section and the intermediate pipe section so that the bypassed exhaust gas flows in the bypass passage; and an exhaust valve located at an upstream end in the flow direction of the exhaust gas in the intermediate pipe portion to switch the flow of the exhaust gas between the heat recovery passage and the bypass passage.

In the above aspect, the exhaust heat recovery apparatus may further include: a static mixer installed in the inner pipe section to stir the flowing coolant.

It may be preferable that the exhaust valve has a valve body and a valve body rod at about the middle position of the valve body, wherein the valve body rod is disposed substantially at the middle position in the width direction or diameter direction of the intermediate pipe portion.

It may be preferred if the exhaust valve includes a plurality of valve assemblies in the form of a double door structure, each of which Valve assembly having a valve body and a valve body rod in an end portion of the valve body, the valve body rod is arranged in each of the valve assemblies in an end portion in the width direction or diameter direction in the intermediate pipe section, and then, when the exhaust valve is fully closed, the upstream end in the flow direction of the exhaust gas within of the intermediate pipe portion is blocked by the valve body of the valve assemblies, whereas when the exhaust valve is fully opened, an upper end portion of the valve body in the valve assemblies is configured to approach the outer pipe portion substantially to an upstream end in the flow direction of the exhaust gas within the bypass passage lock.

In the structures and peculiarities of the present invention explained above, the inner pipe portion with the coolant flowing therein is sequentially covered by the heat recovery passage formed of the inner pipe portion and the intermediate pipe portion and the bypass passage, the bypass passage being formed again by the intermediate pipe portion and the outer pipe portion. This makes it possible to prevent the amount of recovery heat recovered from the coolant from being reduced due to the influence of the running wind. In addition, since the heat recovery passage is formed in a linear shape, the heat recovery passage allows a smooth flow of exhaust gas therein, and the sectional area of the passage is also set in the inner pipe portion in which the coolant flows. This allows a reduction in the pressure loss of both the exhaust gas and the coolant. By adjusting an opening of the exhaust valve, and thus adjusting a flow rate of the exhaust gas flowing into the heat recovery passage, the amount of heat recovery by the coolant can be easily controlled.

The features and other features as well as advantageous effects of the present invention will become more apparent from the following description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings show:

1 an exhaust heat recovery device in a state without heat recovery according to a first embodiment of the invention, wherein 1A a longitudinal sectional view of the device and 1B a cross-sectional view along the line II in 1A is;

2 an exhaust heat recovery device in a state of heat recovery according to the second embodiment of the invention, wherein 2A a longitudinal sectional view of the device and 2 B a cross-sectional view taken along a line II-II in 2A is;

3 an exhaust heat recovery device in a state without heat recovery according to a second embodiment of the invention, wherein 3A a longitudinal sectional view of the device is and 3B a cross-sectional view taken along a line III-III in 3A is;

4 an exhaust heat recovery device in a state of heat recovery according to the second embodiment of the invention, wherein 4A a longitudinal sectional view of the device is and 4B a cross-sectional view taken along a line IV-IV in 4A is; and

5 Fig. 12 is a cross-sectional view showing an exhaust heat recovery unit of a first type of conventional technology.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments for carrying out the invention will be explained with reference to the drawings.

First Embodiment (FIGS. 1 and 2)

With reference to the 1 and 2 In the following, a first embodiment of the invention will be described.

Referring to the 1 and 2 includes an exhaust heat recovery device 10 This embodiment, an inner tube section 11 , an intermediate pipe section 12 , an outer pipe section 13 and an exhaust valve 14 , The exhaust heat recovery device 10 with the above construction serves for the continuous recovery of heat from exhaust gas (exhaust gas) 1 , which comes from an engine, not shown, in a coolant (cooling water 2 the engine in this embodiment), during the start-up phase of the engine as well as in normal operation and high-load operation of the engine, wherein the recovered heat serves to warm the engine and to heat the vehicle cabin, which acts as a heat source for a Rankine process heater ,

For example, the inner pipe section 11 designed as a tube shot, in which the cooling water 2 flows, and in it is a static mixer 15 built-in. The static mixer 15 sits down together from a plurality of assembled right-handed blades 15A on the right and several left-hand blades 15B on the left side, with the right and left blades arranged alternately in the sweeping direction. A crossing angle between a right-handed blade 15A and a left-handed blade 15B is for example 90 degrees. Therefore, this will be in the inner pipe section 11 flowing cooling water 2 from the static mixer 15 inside the inner pipe section 11 touched.

For example, the intermediate pipe section is also 12 formed as a tube shot, arranged in the outer peripheral region of the inner tube section 11 with a predetermined distance from this. Between the intermediate pipe section 12 and the inner pipe section 11 is a heat recovery channel 16 formed, which is configured so that in the inner pipe section 11 located cooling water 2 Heat of the introduced exhaust gas 1 by a heat exchange process (hereinafter simply referred to as heat exchange) is recovered.

The outer pipe section 13 is also designed as a tube, for example, arranged on the outer peripheral side of the intermediate pipe section 12 with a predetermined distance from this. Between the outer pipe section 13 and the intermediate pipe section 12 is a bypass channel 17 formed to the exhaust 1 which without introduction into the heat recovery channel 16 is diverted through the bypass channel 17 to flow.

In addition, the exhaust valve has 14 a valve body 18 in the form of a disc and a valve body rod 19 approximately in the central position (for example, the location of a diameter) of the valve body 18 , The exhaust valve 14 is located at an upstream end in the flow direction of the exhaust gas 1 within the intermediate pipe section 12 , In particular, the valve body rod 19 the exhaust valve 14 rotatable at about the intermediate position in the diameter direction or width direction (a diameter direction D in this embodiment) of the intermediate pipe section 12 stored, at an upstream end in the flow direction of the exhaust gas 1 within the intermediate pipe section 12 ,

The intermediate pipe section 12 has on the upstream side an open end, in which the valve body 18 the exhaust valve 14 perpendicular to a central axis O of the intermediate pipe section 12 is arranged, and in the 1A and 1B is the opening of the exhaust valve 14 shown in a fully closed state. In such an embodiment of the valve body 18 this will be in the outer pipe section 13 introduced exhaust 1 from the valve body 18 the exhaust valve 14 blocked, leaving the exhaust 1 not in the heat recovery channel 16 within the intermediate pipe section 12 flows, but the entire exhaust gas amount of the exhaust gas 1 through the bypass channel 17 in the outer pipe section 13 flows as indicated by the arrow A in 1A is indicated. For this reason, the heat of the exhaust gas 1 hardly of the cooling water inside the inner pipe section 1 added.

When the valve body 18 the exhaust valve 14 a position parallel to the central axis O of the intermediate pipe section 12 takes, is the opening of the exhaust valve 14 brought into a fully open state ( 2 ). In this case, this flows into the outer pipe section 13 introduced exhaust 1 through the heat recovery channel 16 within the intermediate pipe section 12 and through the bypass channel 17 within the outer pipe section 13 , as in 2A indicated by the arrows B and C, and the heat of the heat recovery through the channel 16 flowing exhaust gas 1 is from the inside of the inner pipe section 10 flowing cooling water 2 taken up due to the heat exchange process.

Depending on the opening of the exhaust valve 14 which is at a predetermined position in a region orthogonal to the central axis O of the intermediate pipe section 12 is adjustable to a state parallel to the central axis O, the exhaust gas flows 1 within the outer pipe section 13 to the heat recovery channel 16 within the intermediate pipe section 12 , and the heat of the exhaust gas 1 becomes the one in the inner pipe section through the heat exchange process 11 flowing cooling water 2 recovered.

• (1) Der Innenrohrabschnitt 11, in welchem das Kühlwasser 2 strömt, ist von dem Wärmerückgewinnungskanal 16 abgedeckt, welcher gebildet wird durch den Innenrohrabschnitt 11 und den Zwischenrohrabschnitt 12, wobei der Wärmerückgewinnungskanal 16 weiterhin abgedeckt wird von dem Bypasskanal 17, der durch den Zwischenrohrabschnitt 12 und dem Außenrohrabschnitt 13 gebildet wird. Hierdurch ist es möglich, zu verhindern, dass die von dem Kühlwasser 2 zurückgewonnene Wärme verringert wird aufgrund des Einflusses von Fahrtwind, der außerhalb des Außenrohrabschnitts 13 vorbeiströmt. Im Ergebnis wird die Wiedergewinnungseffizienz der Abgaswärme verbessert.
• (2) Der Wärmerückgewinnungskanal 16, der aus dem Innenrohrabschnitt 11 und dem Zwischenrohrabschnitt 12 gebildet wird, hat eine linear verlaufende Gestalt, so dass das Abgas 1 glatt durch das Innere des Wärmerückgewinnungskanals 16 strömt, und der Kanal besitzt eine große Querschnittsfläche, um den statischen Mischer 15 innerhalb des Innenrohrabschnitts 11 aufnehmen zu können, in welchem das Kühlwasser 2 strömt. Demzufolge lässt sich ein Druckverlust sowohl des Abgases 1 als auch des Kühlwassers 2 verringern. Im Ergebnis wird es möglich, eine Beeinträchtigung der Ausgangsleistung und eine Beeinträchtigung des Wirkungsgrads des Kraftstoffs im Normalbetrieb und im Hochleistungsbetrieb des Motors zu vermeiden. Folglich wird ein Abgaswärme-Wiedergewinnungssystem 10 geschaffen, welches sich für eine kontinuierliche Wärmerückgewinnung während des Normalbetriebs und des Hochlastbetriebs des Motors eignet.
• (3) Durch Einstellen der Öffnung des Abgasventils 14 lässt sich ein Strömungsdurchsatz des in den Wärmerückgewinnungskanal 16 einströmenden Abgases 1 einstellen, und damit lässt sich in einfacher Weise eine Rückgewinnungsmenge an Wärme seitens des im Inneren des Innenrohrabschnitts 11 fließenden Kühlwassers 2 steuern. Im Ergebnis ist es, wenn die aus dem Abgas zurückgewonnene Wärme als Wärmequelle für eine Heizvorrichtung des Rankine-Prozesses genutzt wird, möglich, die Wärmemenge zu steuern, die seitens des Rankine-Prozess-Systems angefordert wird.
• (4) Der Innenrohrabschnitt 11 beinhaltet den statischen Mischer 15, der das Kühlwasser 2 rührt und zum Strömen veranlasst, wodurch der Wirkungsgrad des Wärmeaustauschs zwischen dem durch den Wärmerückgewinnungskanal 16 strömenden Abgases 1 außerhalb des Innenrohrabschnitts 11 einerseits und dem Kühlwasser in dem Innenrohrabschnitt 11 andererseits erhöht. Aus diesem Grund lässt sich die aus dem Abgas 1 durch das Kühlwasser 2 zurückgewonnene Wärmemenge steigern.
• (5) Das Abgasventil 14 befindet sich an dem stromaufwärtigen Ende in Strömungsrichtung des Abgases 1 innerhalb des Zwischenrohrabschnitts 12, und in diesem Zustand befindet sich die Ventilkörperstange 19, die etwa in der Mitte des Ventilkörpers 18 angeordnet ist, etwa an der mittleren Stelle in Durchmesserrichtung D des Zwischenrohrabschnitts 12. Wenn also das Abgas 1 in den Wärmerückgewinnungskanal 16 innerhalb des Zwischenrohrabschnitts 12 strömt, wird das Abgas 1 von dem Ventilkörper 18 und der Ventilkörperstange 19 verwirbelt und in einen turbulenten Strömungszustand gebracht. Im Ergebnis ist es möglich, die Wärmerückgewinnungsmenge aus dem Abgas 1 zu steigern, welches innerhalb des Wärmerückgewinnungskanals 16 in einen Zustand turbulenter Strömung gebracht wurde, so dass die Wärme in erhöhtem Maß in das im Inneren des Innenrohrabschnitts 11 strömende Kühlwasser 12 abgegeben wird.

By the structure of the first embodiment explained above, the following advantageous effects (1) to (5) are achieved:

• (1) The inner pipe section 11 in which the cooling water 2 flows is from the heat recovery channel 16 covered, which is formed by the inner pipe section 11 and the intermediate pipe section 12 , wherein the heat recovery channel 16 continues to be covered by the bypass channel 17 passing through the intermediate pipe section 12 and the outer tube section 13 is formed. This makes it possible to prevent that from the cooling water 2 Recovered heat is reduced due to the influence of wind, outside the outer pipe section 13 flows past. As a result, the recovery efficiency of the exhaust heat is improved.
• (2) The heat recovery channel 16 coming from the inner pipe section 11 and the intermediate pipe section 12 is formed, has a linear running shape, leaving the exhaust 1 smooth through the interior of the heat recovery channel 16 flows, and the channel has a large cross-sectional area around the static mixer 15 inside the inner pipe section 11 to be able to record in which the cooling water 2 flows. As a result, there is a pressure loss of both the exhaust gas 1 as well as the cooling water 2 reduce. As a result, it becomes possible to prevent the deterioration of the output and the deterioration of the fuel efficiency in the normal operation and in the high-output operation of the engine. Consequently, an exhaust heat recovery system 10 which is suitable for continuous heat recovery during normal operation and high load operation of the engine.
• (3) By adjusting the opening of the exhaust valve 14 can be a flow rate of the heat recovery channel 16 incoming exhaust gas 1 adjust, and thus can be easily a recovery amount of heat from the inside of the inner pipe section 11 flowing cooling water 2 Taxes. As a result, when the heat recovered from the exhaust gas is used as a heat source for a Rankine process heater, it is possible to control the amount of heat requested by the Rankine process system.
• (4) The inner pipe section 11 includes the static mixer 15 that the cooling water 2 stir and caused to flow, whereby the efficiency of heat exchange between that through the heat recovery channel 16 flowing exhaust gas 1 outside the inner pipe section 11 on the one hand and the cooling water in the inner pipe section 11 on the other hand increased. Because of this, it can be removed from the exhaust 1 through the cooling water 2 Increase recovered heat quantity.
• (5) The exhaust valve 14 is located at the upstream end in the flow direction of the exhaust gas 1 within the intermediate pipe section 12 , and in this state is the valve body rod 19 , which is roughly in the middle of the valve body 18 is arranged, approximately at the middle point in the diameter direction D of the intermediate pipe section 12 , So if the exhaust 1 in the heat recovery channel 16 within the intermediate pipe section 12 flows, becomes the exhaust gas 1 from the valve body 18 and the valve body rod 19 swirled and brought into a turbulent flow state. As a result, it is possible to recover the heat recovery amount from the exhaust gas 1 to increase, which within the heat recovery channel 16 was brought into a state of turbulent flow, so that the heat in an increased degree in the interior of the inner pipe section 11 flowing cooling water 12 is delivered.

Second Embodiment (FIGS. 3 and 4)

Based on 3 and 4 In the following, a second embodiment will be explained. In particular 3A a cross-sectional view of an exhaust heat recovery apparatus in a state without heat recovery of a second embodiment of the invention, and 3B is a cross-sectional view taken along a line III-III in 3A , 4A FIG. 15 is a cross-sectional view of the exhaust heat recovery apparatus of FIGS 3A and 3B in the state of heat recovery, and 4B is a cross-sectional view taken along the line IV-IV in FIG 4A ,

According to the second embodiment 3 and 4 For example, components or elements corresponding to those of the first embodiment are given the same reference numerals to simplify or partially obviate the description.

An exhaust heat recovery device 20 The second embodiment differs from that of the first embodiment in that an intermediate pipe section 21 and an outer pipe section 22 are formed in the form of a rectangular tube, and that an exhaust valve 23 a plurality of valve assemblies 24 includes.

In this embodiment, each of the valve assemblies is 24 with a valve body 25 in the form of a square plate and a valve body bar 26 fitted to one end portion of the valve body 25 is provided, wherein the valve assembly 24 This embodiment, for example, a pair of valve assemblies 24 form, which are arranged in the form of a double door structure, thereby an exhaust valve 23 to build.

In the structure explained above, the valve body rod is 26 each of the valve assemblies 24 in an end portion in the width direction or a diameter direction (in the widthwise direction W in this embodiment) of the intermediate pipe portion 21 at an upstream end in the flow direction of the exhaust gas 1 within the intermediate pipe section 22 arranged.

In particular, the valve body bar 26 a valve assembly 24 and the valve body rod 26 the other valve body assembly 24 at the opposite ends in the width direction of the intermediate pipe section 21 arranged so that these valve arrangements 24 to form the structure of a double door.

In addition, the valve body 25 all valve arrangements 24 that the exhaust valve 23 form such that their surfaces and shapes are equal to or greater than a cross section of the channel at the upstream end in the flow direction of the exhaust gas 1 within the intermediate pipe section 21 , So while the exhaust valve 23 is completely closed ( 3A and 3B ), the cross section of the channel at the upstream end becomes in the flow direction of the exhaust gas 1 within the intermediate pipe section 21 from the valve bodies 25 all valve arrangements 24 blocked. In such an embodiment, this flows into the outer tube section 22 introduced exhaust 1 through the bypass channel 17 as indicated by the arrow P in 3A is shown and does not flow into the heat recovery channel 16 ,

As in the 4A and 4B is shown, the valve body 25 all valve arrangements 24 that the exhaust valve 23 form, configured to have an upper end portion 25A have, who is the outer tube section 22 comes close when the exhaust valve 23 is fully open, leaving an upstream end in the flow direction of the exhaust gas 1 in the bypass channel 17 is almost completely locked. So if the exhaust valve 23 is fully open, although the exhaust gas flows 1 within the outer pipe section 22 not in the bypass channel 17 but the exhaust 1 is from the valve bodies 25 the valve arrangements 24 directed so that substantially the entire amount of the exhaust gas 1 in the heat recovery channel 16 flows as indicated by the arrow Q in 4A is illustrated.

In addition, in this embodiment, the heat recovery passage 16 between the inner pipe section 11 and the intermediate pipe section 21 formed while the bypass channel 17 between the intermediate pipe section 21 and the outer tube section 22 is formed.

• (6) Zu der Zeit, zu der das Abgasventil 23 vollständig geöffnet ist, kommt der obere Endabschnitt 25A des Ventilkörpers 25 in sämtlichen Ventilanordnungen 24 dem Außenrohrabschnitt 22 nahe, und das stromaufwärtige Ende in Strömungsrichtung des Abgases 1 innerhalb des Bypasskanals 17 ist im großen und ganzen durch die Ventilkörper 25 sämtlicher Ventilanordnungen 24 gesperrt. Folglich wird es möglich, den Strömungsdurchsatz des vom Inneren des Außenrohrabschnitts 22 in den Bypasskanal 17 strömenden Abgases 1 im wesentlichen auf Null einzustellen, um dadurch das gesamte Abgas 1 im Inneren des Außenrohrabschnitts 22 in den Wärmerückgewinnungskanal 16 einzuleiten. Im Ergebnis wird es möglich, die Menge an zurückgewonnener Wärme aus dem Abgas 1 durch das in dem Innenrohrabschnitt 11 fließende Kühlwasser 2 deutlich zu steigern.

By the structure and configuration of the second embodiment described above, in addition to the same effects (1) to (4) of the first embodiment, the following advantageous effects (6) are obtained:

• (6) At the time when the exhaust valve 23 is fully open, comes the upper end section 25A of the valve body 25 in all valve arrangements 24 the outer pipe section 22 near, and the upstream end in the flow direction of the exhaust gas 1 within the bypass channel 17 is by and large through the valve body 25 all valve arrangements 24 blocked. Consequently, it becomes possible to control the flow rate of the inside of the outer pipe section 22 in the bypass channel 17 flowing exhaust gas 1 set substantially to zero, thereby the entire exhaust gas 1 inside the outer pipe section 22 in the heat recovery channel 16 initiate. As a result, it becomes possible to control the amount of recovered heat from the exhaust gas 1 through that in the inner pipe section 11 flowing cooling water 2 significantly increase.

It should be further noted that the present invention is not limited to the described embodiments, but that numerous changes or modifications are possible without departing from the scope of the invention.

For example, in the first and second embodiments, depressions and projections, for example, wings, on an outer surface of the inner pipe section 11 be provided to the amount of heat recovery from the exhaust 1 in addition to increase. In addition, the cross-sectional shapes of the inner pipe section 11 , the intermediate pipe section 12 respectively. 21 and the outer pipe section 13 respectively. 22 have any shape of a circular shape and a polygon shape.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2010-31671 [0003]
• JP 2001-30741 [0003]

Claims (4)

Exhaust heat recovery apparatus comprising: an inner pipe section in which a coolant flows; an intermediate pipe portion disposed outside the inner pipe portion at a predetermined interval to form a heat recovery passage between the intermediate pipe portion and the inner pipe portion for recovering heat of the introduced exhaust gas into the coolant; an outer pipe section disposed outside the intermediate pipe section at a predetermined distance therefrom to form a bypass passage between the outer pipe section and the intermediate pipe section so that the bypassed exhaust gas flows in the bypass passage; and an exhaust valve located at an upstream end in the flow direction of the exhaust gas in the intermediate pipe section to switch the flow of the exhaust gas between the heat recovery passage and the bypass passage. The exhaust heat recovery apparatus according to claim 1, further comprising a static mixer installed in the inner pipe section for stirring the flowing coolant. The exhaust heat recovery apparatus according to claim 1 or 2, wherein the exhaust valve has a valve body and a valve body rod at about the middle position of the valve body, wherein the valve body rod is disposed substantially at the middle position in the width direction or diameter direction of the intermediate pipe section. The exhaust heat recovery apparatus of claim 1 or 2, wherein the exhaust valve includes a plurality of valve structures in the form of a double door structure, each valve assembly comprising a valve body and a valve body rod in an end portion of the valve body, the valve body rod in each of the valve assemblies in a width direction end portion or diameter direction is disposed in the intermediate pipe section, and when the exhaust valve is fully closed, the upstream end in the flow direction of the exhaust gas within the intermediate pipe section is blocked by the valve body of the valve assemblies, whereas when the exhaust valve is fully opened, an upper end region of the Valve body is configured in the valve assemblies to approach the outer tube portion to substantially block an upstream end in the flow direction of the exhaust gas within the bypass passage.

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