DE102009039833A1 - Heat transfer device and method for producing such a heat transfer device - Google Patents

Abstract

To improve the strength and efficiency of die-cast heat transfer devices, it is proposed that in the first section (14) of the base housing part (12) two opposite peripheral walls (20, 26) are fixedly connected to one another by ribs (24). This is achieved by pulling the casting mold after casting the base housing part (12) and before joining the cover part (22) forming the ribs (24) of the first section (14) from a front side (8) of the base housing part (12) A mold insert for demolding the ribs (30) of the second section (16) from the open peripheral wall (20) is pulled out of the casting mold to form a heat transfer device with improved efficiency and increased component strength by reducing the pressure-loaded explosive surface.

Description

The invention relates to a heat transfer device for an internal combustion engine having an outer housing, an inner housing, which is arranged in the outer housing and flows around the coolant and can be flowed through by a medium to be cooled, and which has a basic housing part, which has a first, closed over the circumference portion and a second section circumferentially open on one side, which is closed by a cover part and a method for producing such a heat transfer device, wherein the heat transfer device is produced by die-casting and the cover part with the basic housing part by welding, in particular friction stir welding, is connected.

Such heat transfer devices are used for example as a cooler in internal combustion engines. They serve to cool exhaust gases to improve the combustion process or to cool the charge air. It is known to produce heat exchangers from a plurality of die-cast shells arranged one inside the other, ribs extending from the die-cast shells into the channel through which the fluid to be cooled flows. The shell, from which the ribs extend into the channel through which the fluid to be cooled flows, simultaneously serves as a partition between the channel through which the cooling fluid flows and the channel through which the fluid to be cooled flows, so that a coolant jacket is formed between the inner housing and the outer housing.

Such a heat transfer device is, for example, in the DE 10 2005 058 204 B4 disclosed. This produced in the die-casting heat exchanger has a coolant jacket between the inner housing and outer housing and is flowed through in a U-shape of exhaust gas. The inner housing consists of a basic housing part, which is closed by a lid. From the cover and the bottom of the base housing part extend to improve the efficiency broken ribs in the direction of the opposite wall. In order to be able to arrange ribs over as long as possible a running distance of the exhaust gas, which extend into the channel, the area of the basic housing part, in which a closed peripheral wall is present, is kept as short as possible. Thus, a mold insert for forming the ribs can be removed from the side of the lid part from the base housing part after casting.

A disadvantage of a heat exchanger constructed in this way, however, is that problems arise with the strength of the heat exchanger and its ribs fixed on one side during operation.

It is therefore an object to provide a heat transfer device and a method for producing such a heat transfer device, by means of which the component strength is increased compared to the prior art and at the same time improved radiator efficiencies can be achieved. In the production as possible costs should be saved.

This object is achieved by an apparatus and a method according to the characterizing part of claims 1 and 6. Characterized in that in the first portion of the base housing part, two opposite peripheral walls are firmly connected by ribs, the ribs are cooled in the first section of both opposite sides. It is thus discharged heat in both directions. In addition, increases the same size, the heat transfer surface, since the ribs can be formed from the inlet. For this purpose, after the casting of the base housing part and before connecting the cover part to the base housing part, a slide for demolding the ribs of the first section from a front side of the base housing part is pulled out of the mold and a mold insert for demolding the ribs of the second section from the open peripheral wall of the Drawn mold. Using the additional slider does not require extra time. Instead, the first section can be made much longer without loss of efficiency, so that the length of the weld decreases when attaching the lid. As a result, processing time and thus processing costs can be reduced. In addition, the strength of the heat transfer device increases due to the increased rigidity of the base housing part and the reduction of the lid size and thus weld length.

Preferably, the ribs extend in the main flow direction of the fluid to be cooled over the entire first portion. Thus, the maximum cooling effect of the ribs and at the same time the maximum rigidity of the basic housing part is achieved.

In an advantageous embodiment, the ribs in the region of the closed peripheral wall in the main flow direction have a greater extent than the interrupted in the main flow direction interrupted ribs. Thus, in this area initially a uniform flow without breaks, whereby pressure losses are reduced. At the same time compared to known designs, the pressure-loaded explosive surface reduced, so that an improved strength is achieved.

In a preferred embodiment, the channel to be flowed through by the fluid to be cooled is U-shaped, wherein a rib arranged in the first section serves as a partition wall, via which an inlet region is separated from an outlet region. Compared to other coolers can be reduced by the U-shape of the axial space. At the same time an overflow of the partition is reliably prevented by the bilateral connection of serving as a partition rib, which in turn increases the efficiency of the heat transfer device, since short-circuit currents are avoided, which otherwise occur especially in areas highest pressure gradient, ie between inlet and outlet.

In a further embodiment, the serving as a partition rib extends into the second portion of the base housing part, wherein the lid part rests on serving as a partition rib in the second section. This also largely prevents short-circuit currents, since there are no gaps in the dividing wall and the equalized flow from the first section initially does not tend to overflow the dividing wall.

It is thus provided a heat transfer device with improved efficiency, at the same time by reducing the size of the lid, the pressure-loaded explosive surface is reduced, so that higher component strengths arise. At the same time the manufacturing costs are reduced in particular by shortening the weld.

An embodiment is shown in the figures and will be described below.

1 shows a perspective view of an inner housing of a heat transfer device according to the invention.

2 shows a perspective view of the in 1 illustrated inner housing with partially cut body.

In the 1 is an inner case 2 a heat transfer device according to the invention shown, which is surrounded in the assembled state by an outer housing, not shown, that of a closed back 4. of the inner casing 2 against a front flange 6 of the inner casing 2 is pushed and welded there. This results between the outer housing and the inner housing 2 a coolant jacket, which is the inner casing 2 with the exception of an open front 8th of the inner casing 2 completely surrounds. Through the inner housing 2 trained bridges 10 For example, the coolant flow in the coolant jacket can be forcibly guided so that dead spaces are avoided and uniform cooling of the entire inner housing 2 is reached.

The inner case 2 has a basic housing part 12 on which from the front 8th to the back 4. considered, two consecutive sections 14 . 16 having. The first paragraph 14 has a closed peripheral wall 18 consisting of four substantially perpendicular to each other arranged side walls. The following, second section 16 has over its periphery an open upper peripheral wall 20 on, which in the figures by a substantially plate-shaped cover part 22 is closed.

The first paragraph 14 of the basic housing part 12 has ribs 24 on, extending from the upper perimeter wall 20 to the lower peripheral wall 26 and over the entire length of the first section 14 extend. They are integral with the closed peripheral wall 18 manufactured, as will be described below. This also means that a solid connection between the ribs 24 and the opposite peripheral walls 20 . 26 which does not exist only through the lateral peripheral walls 28 but also through the ribs 24 connected to each other.

In the second section 16 ribs extend 30 alternately from the cover part 22 and from the lower peripheral wall 26 of the basic housing part 12 in the interior of the inner housing 2 , They each end in front of the opposite wall. These ribs 30 are also in rows one behind the other, with the successive rows are offset from one another.

One of the ribs, which is in the middle area of the open front 8th is arranged, without interruption from the first section 14 to the second section 16 of the inner casing 2 continued. This rib serves as a partition 32 and ends in front of the closed back 4. , so that there is a U-shaped deflection of a media stream to be cooled. In the first part 14 is thus through the partition 32 an inlet area 34 of the inner casing 2 from an outlet area 36 separated. In the second section 16 this extends as a partition 32 Serving rib from the lower peripheral wall 26 towards the opposite upper peripheral wall 20 at the lid part 22 loose on the partition 32 rests. Here, if necessary, a small distance must be maintained to tensions by a firm contact of the cover part 22 on the partition 32 after connecting the cover part 22 with the basic housing part 12 to avoid. Since in this area the pressure gradient between the two flow-through halves is already significantly lower than at the inlet or outlet area, the resulting short-circuit currents are largely negligible.

Inside the inner housing 2 is a channel to be cooled by the medium to be cooled 38 formed, each by a lateral peripheral wall 28 , the partition 32 , as well as a part of the upper peripheral wall 20 and the lower peripheral wall 26 is limited.

A gas flow of a medium to be cooled can accordingly on the front 8th trained inlet area 34 in the inner housing 2 flow. The gas continues to flow through the first section 14 on one side of the partition 32 past the ribs 24 , As a result, a main flow direction A of the medium is determined. Subsequently, in the second section 16 , can through the interruptions between the ribs 30 Cross flows arise, the main flow direction A is maintained. At the end of the partition 32 finds a reversal of gas flow along the semicircular reverse side 4. of the inner casing 2 instead of. After flowing through the reverse region, the flow is now in the opposite direction of main flow A to the outlet 36 on the front side 8th continued. By the contact of the gas to the side walls 20 . 26 . 28 . 32 and the ribs 24 . 30 There is a very good heat dissipation from the medium to be cooled on the heat exchange surfaces to the coolant.

Especially in the first section 14 the heat transfer device, the heat transfer is very good, since the heat from the ribs 24 can be dissipated on both sides, which is not possible in the following areas.

Such a heat transfer device is manufactured by a die casting with one of the ribs 24 forming slider and one ribs 30 forming mold insert is used, the slider from the front 8th is inserted and can be demolded after the casting process to the front during the mold insert from the top 20 pushed in the die and pulled out there for demoulding. By using these two shaping parts, continuous ribs can be obtained in the first section 24 are made over the slider, which are the opposite perimeter walls 20 . 26 connect to each other while the mold insert the broken ribs 30 forms, which extend from the lower peripheral wall 26 extend upwards. Both types of ribs 24 . 30 have a decreasing cross-section in the removal direction, so that the ribs 24 in the first part 14 in the main flow direction are wedge-shaped, while the ribs 30 have in their respective facing the mounting wall section having a larger cross section in order to ensure a clean demolding can.

After making the basic housing part 12 and the lid part 22 In the die casting process, both can be joined together by friction stir welding. Subsequently, the likewise cast outer housing from the back 4. over the inner housing 2 pushed and with this on the flange 6 welded or bolted with the interposition of a seal.

It should be clear that it is not possible to produce such a U-shaped inner housing with ribs in one piece by die-casting. It is therefore necessary to produce an at least two-part inner housing in which, on the one hand, a high degree of cooler efficiency is achieved and, on the other hand, a high component strength is to be achieved. For this reason, the first section was maximized as possible, without having to dispense with the attachment of ribs below, which in the no longer rectilinear and therefore no longer demouldable to the front area can be produced only by another slider, so that a cover part must be used , In this way, however, a minimized pressure-loaded explosive surface and a significant shortening of the weld and thus the welding time, whereby manufacturing costs are reduced. In addition, the risk of breaking off the heavily loaded first finned ribs is minimized by the bilateral connection to the housing. By this two-sided connection of the ribs on the housing this in turn becomes stiffer and more stable. At the same time, the cooler efficiency increases as well as the complete arrangement of ribs over the entire run length.

Of course, design changes are conceivable within the scope of the main claims. In particular, the arrangement and attachment of the inner housing to or on the outer housing, the arrangement of the webs on the inner housing and the formation of the ribs in the inner housing can be performed differently.

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

• DE 102005058204 B4 [0003]

Claims (6)

Heat transfer device for an internal combustion engine having an outer housing, an inner housing, which is arranged in the outer housing and flows around the coolant and can be flowed through by a medium to be cooled, and which has a basic housing part, which has a first, circumferentially closed portion and a second over the circumference having unilaterally open portion which is closed by a cover part, wherein extend in the flow-through of the fluid to be cooled channel ribs which are interrupted in the main flow direction of the fluid to be cooled, characterized in that in the first section ( 14 ) of the basic housing part ( 12 ) two opposite peripheral walls ( 20 . 26 ) by ripping ( 24 ) are firmly connected. Heat transfer device for an internal combustion engine according to claim 1, characterized in that the ribs ( 24 ) in the main flow direction (A) of the fluid to be cooled over the entire first section ( 14 ). Heat transfer device for an internal combustion engine according to claim 1 or 2, characterized in that the ribs ( 30 ) in the region of the closed peripheral wall ( 18 ) in the main flow direction (A) have a greater extent than the interrupted in the main flow direction (A) interrupted ribs ( 30 ). Heat transfer device for an internal combustion engine according to one of the preceding claims, characterized in that the channel to be cooled by the fluid to be cooled ( 38 ) Is U-shaped, one in the first section ( 14 ) arranged rib as a partition ( 32 ), via which an inlet area ( 34 ) from an outlet area ( 36 ) is disconnected. Heat transfer device for an internal combustion engine according to claim 4, characterized in that as a partition ( 32 ) serving rib in the second section ( 36 ) of the basic housing part ( 12 ), wherein the lid part ( 22 ) on the as a partition ( 32 ) rib in the second section ( 16 ) rests. Method for producing a heat transfer device according to one of the preceding claims, wherein the heat transfer device is produced by die-casting and the cover part is connected to the basic housing part by welding, in particular friction stir welding, characterized in that after the casting of the basic housing part ( 12 ) and before connecting the cover part ( 22 ) with the basic housing part ( 12 ) a slider for demolding the ribs ( 24 ) of the first section ( 14 ) from a front side ( 8th ) of the basic housing part ( 12 ) is pulled out of the mold and a mold insert for removing the ribs ( 30 ) of the second section ( 16 ) from the open peripheral wall ( 20 ) is pulled out of the mold.

Images