WO2007062939A1

WO2007062939A1 - Cooling device for an internal combustion engine

Info

Publication number: WO2007062939A1
Application number: PCT/EP2006/067799
Authority: WO
Inventors: Hans-Jürgen Hüsges; Hans-Ulrich Kühnel; Peter Heuer
Original assignee: Pierburg Gmbh
Priority date: 2005-12-02
Filing date: 2006-10-26
Publication date: 2007-06-07
Also published as: EP1955001A1; EP2413080A3; US20090050302A1; DE102005058204B4; EP2413080A2; DE102005058204A1; JP2009517625A

Abstract

A cooling device is proposed which can be produced by the diecasting process and which has a heat-transfer unit (1; 27, 28) surrounded by an outer shell (14; 31 ), wherein a casing (20) through which coolant flows is formed between the heat-transfer unit (1 ; 27, 28) and the outer shell (14; 31), said casing (20) being subdivided by webs (3, 4, 5, 6; 29, 30, 34, 35, 36, 37) in such a way that a passage (21; 33) through which coolant flows is formed between the outer shell (14; 31) and the outer casing (2) of the heat-transfer unit (1; 27, 28). To this end, the webs (3, 4, 5, 6; 29, 30, 34, 35, 36, 37) are arranged in such a way that this circulating flow is effected in a meander shape. Compared with a spiral flow, this results in degrees of freedom with regard to the arrangement of the coolant inlets (12; 32) and coolant outlets (13; 38). Furthermore, such cooling devices can be produced and assembled in a cost-effective manner and have a high efficiency.

Description

DESCRIPTION

Cooling device for an internal combustion engine

The invention relates to a cooling device, in particular an exhaust gas cooling device for an internal combustion engine with an outer shell, in which at least one heat transfer unit is arranged, which has an outer housing, which separates a formed between the outer shell and the heat transfer unit, by a coolant flow-through jacket of a channel in the heat transfer unit is formed and through which flows the fluid to be cooled, wherein between the outer shell and the outer housing of the heat transfer unit webs are arranged, which limit channels through which coolant flows.

Cooling devices of this kind are used, for example, in internal combustion engines as exhaust-gas cooling devices for reducing pollutant emissions by the exhaust gas being cooled being mixed with the freshly drawn-in air and supplied to the cylinders. By reducing the temperature of the cylinder filling pollutant emissions are reduced. For this purpose, various designs of cooling devices have been registered.

The problem in many of these cooling devices are death areas or vortices in the coolant flow-through jacket, in which no coolant exchange takes place, whereby the efficiency of the cooling device is set significantly lower. Also, boiling of the coolant can cause damage to the cooling device.

In order to avoid such dead water areas and to increase the efficiency of a heat exchanger, cooling devices have been developed, which include a positive guidance of the coolant. Thus, DE 20 48 474 discloses a partition wall for a cooling device, which is arranged in the coolant jacket and defines a channel through which it flows. This cooling device is of cylindrical design, wherein the webs for positive guidance of the coolant flow are formed from a subsequently arranged on the inner Wärmetau- shear unit separating blade which helically surrounds the inner heat exchanger unit, so that a positive guidance in spiral form is achieved around the heat exchanger unit.

A similar embodiment is also known from DE 20 2004 008 737, which e- benfalls discloses a cylindrical heat exchanger whose partitions are spirally arranged so helically around the inner channel. These partitions are formed by a wire which is approximately square. This wire is then firmly bonded to the inner tube, so the heat exchanger unit.

A disadvantage of such embodiments is that in such helical positive guides the heat exchanger is fixed with respect to the arrangement of the coolant inlet and outlet. In a helical flow around the inner heat exchanger unit, the inlets and outlets for the coolant must be located at the axial ends of the heat exchanger.

Furthermore, it is disadvantageous that it is very difficult and costly to manufacture the inner heat exchanger unit to produce, for example, a cuboid or multiple parts, or to arrange a plurality of heat exchanger units in an outer shell, wherein each heat exchanger unit should be completely bypassed as far as possible. In such a case, it would be necessary to be able to accurately associate the helical continuation of the webs delimiting the channels in both parts so that there are no cracks or gaps between the individual parts.

It is therefore an object of the invention to provide a cooling device with a coolant forced guidance, which has high degrees of freedom with respect to the arrangement of the coolant inlet and outlet, wherein at the same time a multi-part ability of an internal heat exchanger unit should be easy to produce. Furthermore, it should be possible, for example, to arrange a plurality of heat exchanger units in a housing, which nevertheless are individually bypassed as completely as possible.

This object is achieved in that the webs which delimit the coolant are arranged in such a way that the heat transfer unit is forcibly circulated in a meandering manner. As a result of this meander-shaped flow, the arrangement of the inlets and outlets can be selected as freely as the shape of the cooling device and the heat exchanger unit. Even with a multi-part heat transfer unit the webs are easy to produce and without offset with the heat transfer unit.

In a preferred embodiment, a first axially extending web is arranged between the outer shell and outer housing of the heat transfer unit, from which circumferentially extending webs extend alternately from both sides of the axially extending web around the heat transfer unit, wherein the webs extending in the circumferential direction at a distance which preferably corresponds to the distance between the circumferentially extending webs, terminate in front of the axially extending web. In such an embodiment, webs which are arranged only perpendicularly to one another and which can be arranged simply and accurately relative to one another, even in the case of a multi-part heat transfer unit, are completely avoided. In such a cooling device, the coolant inlet is arranged at the first axial end of the cooling device and the coolant outlet at the opposite axial end. There is over the circumference a completely positively driven flow around the heat transfer unit and thus a high efficiency.

In an alternative embodiment, between the outer shell and the outer housing of the heat transfer unit, two axially extending webs are provided, of which a first web terminates in front of a last axial section of the cooling device and from which, in the axial direction, alternately from the first one extending web and from the second axially extending web in the circumferential direction extending webs from both sides of the respective axially extending web to the heat transfer unit, wherein the circumferentially extending webs at a distance which preferably corresponds to the distance between the circumferentially extending webs, in front of the other axially extending web , With such an embodiment, the coolant inlet and the coolant outlet can be arranged at the same axial end of the cooling device, so that the cooling device is initially flowed around meandering in its first half and then in its second half. In such an embodiment, the flow of the heat transfer unit can be selected according to a U-shape, so that the cooling device can be operated both in countercurrent and in parallel flow. The arrangement of the webs to each other is easy to produce and dead spaces are still avoided.

In a further alternative embodiment, two transmission units are arranged in an outer shell, between which webs are formed such that each of the heat transfer unit is zwangsumströmt on all sides in cross section. In such a case, it is a two-level cooler, which has the advantage that it is axially less long-lasting, so that in this case, too, there are significantly higher degrees of freedom in comparison to spiral-shaped coolers.

Such an all-round flow around is achieved in that the two heat transfer units are flowed around in cross-section substantially in the form of a figure eight. Additional flow and return flows are thus avoided and coolant inlet and outlet passages can be arranged on the axially opposite sides of the heat transfer unit.

In such a preferred embodiment, an axially extending web is disposed between the outer shell and each of the two heat transfer units, wherein the two axially extending webs are arranged on opposite circumferential sides of the shell and extending in the circumferential direction webs alternately from both sides of the axially extending Bars around the heat Transmission units extend, wherein each first circumferentially extending web terminates at a distance in front of the first axially extending web and each second circumferentially extending web terminates at a distance in front of the second axially extending web. By means of such an embodiment, the flow around the two-storey heat exchanger in the form of an eight is ensured in a particularly simple manner.

In a preferred embodiment, the heat transfer unit is produced by die-casting, so that it is lightweight, for example, when using an aluminum or magnesium die-casting, and yet can be produced inexpensively. At the same time it is suitable for high temperatures.

In a preferred embodiment, the heat transfer unit is composed of an upper part and a lower part, which are connected to one another by welding, in particular friction stir welding. Friction stir welding is particularly suitable for use with magnesium or aluminum die cast coolers. Additional protuberances or eyes for screw connections, as they are known in other cooling devices for connecting two parts together, are not necessary here, so that a very small, yet dense assembly without additional seals is guaranteed.

Preferably, the webs are at least partially disposed on the outer housing of the heat transfer unit, so that no additional inserts are necessary to ensure a functioning forced operation. In Diegussverfah- these webs are then produced in only one manufacturing step with the heat transfer unit.

In a further or alternative embodiment, the outer shell is designed at least in two parts and produced by die-casting, wherein the webs are at least partially formed on an inner wall of the outer shell. Of course, even in such an embodiment, the webs may be completely formed on the outer shell and extend to the outer wall of the heat transfer unit. Also conceivable are intermediate solutions, so that the Webs are partially formed on the outer casing of the heat transfer unit and partially on the inner wall of a two-part outer shell produced. In both cases, additional inserts and thus manufacturing steps are avoided.

In a further embodiment, the webs are formed substantially on the outer housing of the heat transfer unit and have in the connection region between the upper part and lower part interruptions, which are filled in the assembled state by corresponding webs of the outer shell. Such an embodiment is particularly useful in multi-part heat transfer units, which are then welded. Usually this is in the area between the items of the heat transfer unit a free cut necessary to start the appropriate welding tool can. In order nevertheless to avoid an overflow of the coolant in the assembled state at these points, they can be intentionally recessed at the heat transfer unit and filled by corresponding arranged on the inner wall of the outer shell webs in the assembled state again, so that no areas with standing Coolants exist.

In an alternative embodiment, the webs in the connecting region between the upper part and the lower part of the heat transfer unit in the cross-section are formed continuously running. Although this results in slight pressure losses in the coolant jacket, since the cross section is no longer the same over the entire course, but it is possible by such an embodiment that to guide the welding tool on the steadily formed in this area webs, without the reliable separation of the channels to destroy by the bridges.

The claimed cooling devices have a high efficiency, with their size and the arrangement of the coolant inlet and outlet are almost arbitrary. Such cooling devices are simple and inexpensive to manufacture and assemble without having to use additional components.

Three embodiments are illustrated in the drawings and will be described below. FIG. 1 shows a plan view of a heat transfer unit of a cooling device according to the invention.

FIG. 2 shows a side view of the heat transfer unit from FIG. 1.

FIG. 3 shows a view from below of the heat transfer unit of FIGS. 1 and 2.

FIG. 4 shows a view from below of an alternative cooling device with a two-part outer housing, wherein a part of the outer shell is shown cut away.

FIG. 5 shows a sectional view of a top view of the cooling device from FIG. 4.

Figure 6 shows a third embodiment of a cooling device according to the invention in a partially sectioned illustration in plan view.

FIGS. 1 to 3 show a heat transfer unit 1 of a cooling device, which is usually surrounded by a one-piece outer shell, which is not shown here. The heat transfer unit 1 has an outer housing 2, on which webs 3, 4, 5, 6 are formed. Their height corresponds to the distance between an inner wall of the outer shell and the outer housing 2 of the heat transfer unit 1, so that an emerging between the outer shell, not shown, and the heat transfer unit 1 by the coat Webs 3, 4, 5, 6 is divided into a continuous channel 7.

Inside the heat transfer unit 1, a passage through which exhaust gas flows is formed, in which, for example, ribs for better heat transfer can be arranged. In the present embodiment, the heat transfer unit 1 is designed U-shaped, this means that at least one axially extending web is formed in the interior of the heat transfer unit 1, in the rear area is interrupted, thus allowing a diversion of the exhaust gas flow. Accordingly, an exhaust gas inlet 8 and an exhaust gas outlet 9 are formed at the same axial end of the heat transfer unit 1.

In order to be able to guide the coolant flow substantially either against the exhaust gas flow or with the exhaust gas flow along the heat exchanger unit 1, the webs 3, 4, 5, 6 are designed such that the heat transfer unit 1 first in its first half 10 and then in the reverse direction In its second half 11, a meandering forcibly flows around, so that a coolant inlet 12 and a coolant outlet 13 are arranged at the same axial end of the heat transfer unit 1.

For this purpose, two axially extending webs 3, 4 are formed on the outer housing 2 of the heat transfer unit 1, of which there is a first axially extending web 3 on the upper side shown in Figure 1 and a second axially extending web 4 on the bottom of the heat transfer unit 1 shown in FIG , From these axially extending webs 3, 4 extend in the axial direction on both sides of the webs 3, 4 in the circumferential direction alternately webs 5, 6, each ending in front of the arranged on the opposite side axially extending web 4, 3 ends. The distance between the end of a circumferential ridge 5, 6 and the respective affected axial web 3, 4 corresponds substantially to the distance between two consecutive extending in the circumferential direction webs 5, 6, so that there is only a slight pressure drop.

The course of the coolant is now apparent from FIGS. 1 to 3. Via the coolant inlet 12, the coolant flows in the direction of the axial web 3 to be recognized in FIG. 1 and between the end of the circumferentially extending web 6 and the axially extending web 3 between the two webs 5, 6 running in the circumferential direction Coolant along the side wall shown in Figure 2 to the bottom of the heat transfer unit 1, which is shown in Figure 3. Here, the flow is in turn deflected in the axial direction, so that the coolant between the end of the circumferentially extending web 5 and extending in the axial direction of the web 4 in turn, a deflection from 90 ° experiences and between the webs 5, 6 can flow back to the top. This meandering movement now follows with recurring deflections to the other axial end of the heat transfer unit 1, where the coolant can flow on the upper side of the heat transfer unit 1 to be recognized to the opposite side wall of the heat transfer unit 1, as in this area the axially extending web 3 is interrupted. From here, the meander-shaped movement now continues around half the cross section of the heat transfer unit 1 all the way to the outlet 13.

A similar cooling device is shown in FIGS. 4 and 5, whereby here also an outer shell 14 opened in FIG. 4 is shown. On the inner walls of the outer shell 14 double webs 15 are formed, which engage around the webs 3, 4, 5, 6 around, so that a reliable seal is achieved. In order to be able to achieve this, the outer shell is constructed from an upper part 16 and a lower part 17, as can be seen in FIG.

As already shown in FIGS. 1 to 3, the heat exchanger unit 1 is also designed in two parts with an upper part 18 and a lower part 19. The flow around the cooling device shown in FIGS. 4 and 5 takes place in the same way as in connection with FIGS 3, wherein in this view, the jacket 20 and in Figure 5, the inner exhaust gas flowed through channel 21 can be seen, in which ribs 22 extend from both parts 18, 19 in the channel 21. Also, a middle rib 23 can be seen, which separates the first flowed through first half 10 from the opposite flow through the second half 11.

From FIG. 4 it can be seen that in the region of the outer edges of the lid-shaped lower part 19 of the heat transfer unit 1, the webs 5, 6 extending in the circumferential direction have interruptions 24. These interruptions 24 are present because during the attachment of the lower part 19 to the upper part 18, a welding takes place in which the welding tool requires sufficient clearance. A discontinuous course of the ribs 5, 6 at this point means that no exact and tight weld would be possible without destroying the ribs 5, 6. For this Reason these existing interruptions 24 are filled by arranged on the outer shell 14 short webs 25 during assembly of the cooling device. Such a bridge can be seen in particular in FIG.

In the heat transfer unit according to FIGS. 1 to 3, this problem has been solved in another way by the areas between upper part 18 and lower part 19 of the heat transfer unit 1 required for the tool during the welding process being continuous around the ribs 5, 6 arranged on the outer housing 2 are executed. This results in the wave-shaped profile on the underside which can be seen in FIG. This has the advantage that, for example, a friction stir welding method can take place without interrupting the ribs 5, 6, but has the disadvantage that, in order to avoid flow losses, the flowthrough cross section of the coolant channel 20 must be kept the same, so that an accurate calculation of the existing Surfaces must be performed and must be realized in the casting.

It can further be seen in FIGS. 4 and 5 that the cooling device is fastened to the actual cooling device by means of an attachment part 26 on which the exhaust gas inlet 8 and the exhaust gas outlet 9 are formed.

It becomes clear that a reliable forced circulation in meandering form of the heat transfer unit 1 is achieved by both embodiments, with coolant inlet and outlet 12, 13 being arranged at the same axial end of the heat exchanger unit 1. It should be clear that an arrangement of the coolant inlet 12 and the exhaust gas inlet 8 and the coolant outlet 13 and the exhaust gas outlet 9 at axially opposite ends of the cooling device in meandering flow are possible, in which case only an axial web would be needed and alternating from this axial web to both sides, the webs extending in the circumferential direction would have to extend and each would have to end on the axial web before re-encountering.

Another embodiment of a cooling device according to the invention is shown in FIG. The course of the coolant is shown by arrows. On the back existing components or currents are indicated by broken lines.

This cooling device includes in its interior two heat transfer units 27, 28, each of which is forcibly circulated completely around its circumference. This flow takes place in the form of an eight. For this purpose, each of the heat transfer units 27, 28 has an axially extending web 29, 30, which extends from one axial end to the other. The two axially extending webs 29, 30 are located after installation in the outer shell 31 on opposite circumferential sides of the cooling device, so that the axially extending web 29 is shown in dashed lines.

A coolant inlet 32 is again located on the side opposite the present view, from where the coolant flows in the circumferential direction around the first heat transfer unit 27. From here, the coolant continues to flow between the first heat transfer unit 27 and the second heat transfer unit 28, since the further path through the web 30 is interrupted. The coolant continues to flow on the side of the cooling device facing away from this view and around the second heat transfer unit 28 in the circumferential direction. A lateral boundary of the coolant flowed through channel 33 consists of a circumferentially extending web 34 which extends around the entire heat transfer unit 27 and a circumferentially extending web 35 which extends around the entire heat transfer unit 28, but before impinging on the axial web 30th ends. The flow in the circumferential direction thus ends at the axial web 30, where a deflection of the coolant takes place and this continues to flow in the axial direction between the axially extending web 30 extending in the circumferential direction web 35. Now the coolant again undergoes a deflection, since an axial flow is prevented by a web 36 which extends in the circumferential direction around the heat transfer unit 28. It flows around the second heat transfer unit 28, limited by the webs 35 and 36 and flows from here again due to the resistance of the second axial web 29 now between the two heat transfer units 27, 28 on the side corresponding to the present view. In this way, the further course of the coolant also takes place past a web 37 on the first heat transfer unit 27, which in turn ends in front of the web 30 on the rear side, toward a coolant outlet 38. The webs 42 required for this purpose between the two heat transfer units 27, 28 may optionally be formed on one or both of the heat transfer units 27, 28. In the embodiment illustrated in FIGS. 6 and 7, the heat transfer units 27, 28 have a common housing 39, which is closed on opposite peripheral sides by a cover element 40, 41, so that the webs 42 between the heat transfer units 27, 28 are integral with the housing 39 are executed.

When the exhaust gas outlet of the first heat transfer unit 27 is connected to the exhaust gas inlet of the second heat transfer unit 28, the cooling path for the exhaust gas can thus be doubled without having to lengthen a cooling device in its axial length.

It should be clear that such a meandering forced flow of a cooling device ensures the advantages of a completely freely selectable arrangement of the coolant inlet and outlet 12, 13, 32, 38. With the help of this forced flow, a high efficiency of such constructed cooling devices is achieved. Assembly and production costs compared to known designs are significantly reduced. The extent to which the existing webs are formed on the outer shell or on the outer housing of the heat transfer unit or, if appropriate, applied as individual components, remains free. The outer shape of the heat transfer unit is largely free by such an arrangement of the coolant channels leading through the webs.

Claims

PATENT APPLICATIONS

1. Cooling device, in particular an exhaust gas cooling device for an internal combustion engine with an outer shell, in which at least one Wärmeübertra- tion unit is arranged, which has an outer housing, which separates a formed between the outer shell and the heat transfer unit, through which flows through a coolant jacket of a channel which in the heat transfer unit is formed and through which flows the fluid to be cooled, wherein between outer shell and outer housing of the heat transfer unit webs are arranged, which in the shell a

Limiting coolant flow channel, characterized in that the webs (3, 4, 5, 6, 29, 30, 34, 35, 36, 37) are arranged such that the heat transfer unit (1, 27, 28) is zwangsumströmt meandering.

2. Cooling device according to claim 1, characterized in that a first axially extending web is arranged between the outer shell and the outer housing of the heat transfer unit, from which extending in the circumferential direction webs extend alternately from both sides of the axially extending web to the heat transfer unit, wherein in Umfanggehung extending webs at a distance, preferably the

Distance between the webs extending in the direction of the circumference corresponds to the end in front of the axially extending web.

3. Cooling device according to claim 1, characterized in that between the outer shell (14) and outer housing (2) of the heat transfer unit (1) two oppositely disposed axially extending webs (3, 4) are formed, of which a first web (3) a last axial portion of the cooling device ends and from which in the axial direction alternately axially from the first axially extending web (3) and the second axially extending web (4) extending in the circumferential direction webs (5, 6) extend from both sides of the respective axially extending web (3, 4) to the heat transfer unit (1), wherein the circumferentially extending webs (5, 6) at a distance which preferably corresponds to the distance between the circumferentially extending webs (5, 6), in front of the respective other axially extending web (4, 3).

4. Cooling device according to one of claim 1, characterized in that two heat transfer units (27, 28) in an outer shell (31) are arranged, between which webs (29, 30, 34, 35, 36, 37) are formed in that each of the heat transfer units (27, 28) is forcibly bypassed on all sides in cross section.

5. Cooling device according to claim 4, characterized in that the two heat transfer units (27, 28) in cross-section substantially in

Form of an eight are flowed around.

6. Cooling device according to claim 4 or 5, characterized in that between the outer shell (31) and each of the two heat transfer units (27, 28) each have an axially extending web (29, 30) is arranged, wherein the two axially extending webs (29, 30) are arranged on opposite circumferential sides of the channel (33) and that circumferentially extending webs (34, 35, 36, 37) alternately from both sides of the axially extending webs (29, 30) to the heat transfer units (27, 28), each first circumferentially extending web

(34, 35) terminates at a distance in front of the first axially extending web (30) and every second circumferentially extending web (36, 37) terminates at a distance in front of the second axially extending web (29).

7. Cooling device according to one of the preceding claims, characterized in that the heat transfer unit (1, 27, 28) is produced by die-casting.

8. Cooling device according to one of the preceding claims, characterized in that the heat transfer unit (1, 27, 28) of an upper part (18) and a lower part (19) is constructed, which are connected by welding in particular friction stir welding.

9. Cooling device according to one of the preceding claims, characterized in that the webs (3, 4, 5, 6; 29, 30, 34, 35, 36, 37) at least partially on the outer housing (2) of the heat transfer unit (1, 27, 28) are formed.

10. Cooling device according to one of the preceding claims, characterized in that the outer shell (14) is at least made in two parts and produced by die-casting, wherein the webs (15, 25) are at least partially formed on an inner wall of the outer shell (14).

11. Cooling device according to one of the preceding claims, characterized in that the webs (3, 4, 5, 6) are formed substantially on the outer housing of the heat transfer unit (1) and in the connecting region between upper part (18) and lower part (19) interruptions ( 24), which in the assembled state by corresponding

Webs (25) of the outer shell (14) are filled.

12. Cooling device according to claim 9, characterized in that the webs (5, 6) in the connecting region between the upper part (18) and lower part (19) of the heat transfer unit (1) are formed to extend continuously in cross section.