DE102005036045A1 - Cooling device for internal combustion engine has ribs which extend perpendicularly to main flow direction into flow-washed passage of heat exchanger in alternating manner from two opposite side walls of passage - Google Patents

Abstract

The cooling device for an internal combustion engine has an arrangement in which ribs (22) extend perpendicularly to the main flow direction into the flow-washed passage (4) of a heat exchanger (3) in an alternating manner from the two opposite side walls (20,21) of the passage. The cross section to the main flow direction of the passage through each rib is completely closed over the height of the side wall, and is closed at least by half in the direction of the extent of each rib.

Description

The The invention relates to a cooling device for internal combustion engines with an outer shell, in the one in the die-casting process integrally manufactured heat exchanger element is used, wherein between the heat exchanger element and the outer shell one of a to be cooled Fluid permeable Channel is arranged and in the heat exchanger element a coolant flowed through Channel is formed, which by itself in the main flow direction extending side walls is limited.

Such cooling devices can be used in internal combustion engines, for example for exhaust gas cooling or intercooling. Above all, multi-part cooling devices are known, which are designed as plate heat exchangers or tube bundle heat exchangers. For positive guidance of the fluid to be cooled and to increase the residence time of the gas to be cooled, it is from the DE 43 105 38 A1 known to arrange partition plates for positive guidance of the gas to be cooled in the heat exchanger, so that the existing coolant-carrying tube bundles are flowed transversely, whereby the heat transfer to the fluid to be cooled is to be improved.

A such cooler However, it has the disadvantage that they are composed of many individual parts must be set, which in their size exactly matched have to be. This results in high assembly times and costs. Furthermore there is a re the size continues relatively poor heat transfer between the refrigerant and to be cooled Fluid.

Therefore, in the DE 103 21 533 B4 discloses an exhaust gas cooler in which an integrally formed in the die casting process heat exchanger element is mounted in an outer shell, which has in the fluid-carrying channel extending ribs over which the heat transfer of the coolant is significantly improved. In this case, the coolant flows in a channel which is arranged centrally in the heat exchanger element and is delimited by side walls extending in the main flow direction of the fluid to be cooled and of the coolant.

A such a cooling device reduces the assembly costs in particular by the used Die casting process in comparison to known cooling devices, although significant and also has an improved size Heat transfer compared to other known heat exchangers, however available in small still in terms of space its cooling capacity limited.

task The invention is therefore the cooling performance of such cooler continue to improve without having to extend the length, with each additional after application, the possibility should exist, the desired Heat transfer as well as the occurring pressure losses according to the application discontinue without a complete new one Construction of the cooling device perform too have to. The advantages regarding a simple and inexpensive Production and installation should be maintained.

These Task is solved by that is in the main flow direction alternately from two opposite sidewalls of the coolant perfused Channel of the heat exchanger element Ribs perpendicular to the main flow direction extend into the channel, wherein the cross section to the main flow direction of the channel through each rib the height the side wall completely is closed and in the extension direction of each rib at least in half is closed. This creates a positive guidance of the coolant in the coolant channel in serpentine shape and thus a significantly increased residence time of the coolant. This leads to a significant improvement in heat transfer and the possibility of the Distance of the ribs to each other and the pressure loss in the coolant channel to set arbitrarily.

In An advantageous embodiment of the invention is the flow-through cross-section of the coolant perfused Channels between the ribs and between the ribs and the side walls in the Essentially constant. This means no flow losses caused by occurring pressure differences within the channel, so that an adjustment of the desired pressure loss can be easily realized is.

In a preferred embodiment The ribs have a steadily shrinking in the direction of extent Cross-section width, so that the mass of the cooling device at about the same good Heat transfer is reduced. At the same time the manufacturability and the heat transfer compared to thin ones Ribs improved.

Preferably has the heat exchanger element at its to be cooled from Flow through the fluid Channel facing side in the flow direction extending ribs, causing pressure loss in the area of cooling Fluids are significantly reduced and a good heat transfer is reached.

In a preferred embodiment is that of the to be cooled Fluid can flow through Channel through the heat exchanger element closed, so that in turn components are saved and a simple Manufacturability ensured by reducing the manufacturing and assembly costs becomes.

Farther is the coolant flowed through Channel preferably closed by a lid on which and / or outlet for the coolant can be arranged.

Of Furthermore, it has proved to be advantageous, the connection between outer shell and heat exchanger element and heat exchanger element and make covers by friction stir welding, since this is a cost-effective connection method which is also suitable for die castings suitable.

In a continuing Embodiment is in the outer shell the cooling device an intermediate wall is formed, which can be flowed through by the fluid to be cooled channel separates from a bypass channel, wherein the bypass channel and the from to be cooled Fluid can flow through Channel can be switched on and off by means of a bypass flap. This will it is possible For example, when used as an exhaust gas cooler this in the warm-up phase to bypass the internal combustion engine without additional To provide pipelines.

In another in turn embodiment are the bypass flap and a metering valve as well as the heat exchanger element in the outer shell the cooling device arranged so that extra housing parts saved and thus weight and costs are reduced. The entire unit can be manufactured as a complete module and the Individual parts are optimally matched to each other.

It thus becomes a cooling device created, which significantly reduces the necessary number of components, a manufactured in comparison with known die-cast coolers higher Efficiency, and thus can be built smaller. In addition is it possible, the entire unit as a complete module with optimally coordinated Components to manufacture and offer. Furthermore, the setting the pressure losses in the coolant channel possible and by different distribution of the transverse ribs to be arranged easy to change depending on the application.

One embodiment is shown in the drawings and will be described below.

1 shows a cooling device according to the invention in a three-dimensional representation in modular design with attachments.

2 also shows in a three-dimensional sectional representation of a section of the cooling device according to the invention 1 with cut-off lid.

3 again shows the cooling device according to the invention 1 in three-dimensional representation with partially cut outer shell and lid.

The 1 shows a cooling device according to the invention 1 in modular design with an outer shell 2 , which forms a unilaterally open channel into which a heat exchanger element 3 is used such that the open side of the outer shell 2 through this heat exchanger element 3 is closed. This heat exchanger element 3 also has a unilaterally open channel through which coolant flows 4 up in the 2 and 3 it can be recognized and as in 1 visible again by a lid 5 is closed. On the lid 5 are additional attachments of the cooling device 1 attached. In the present embodiment, these are a coolant inlet nozzle 6 and a vacuum box 7 which in conjunction with a solenoid valve 8th stands and as an actuator in 3 recognizable bypass flap 9 serves.

On the outer shell 2 are an unillustrated inlet nozzle for the fluid to be cooled and an outlet nozzle 10 for the fluid to be cooled as well as an outlet nozzle 11 for the coolant present. The outlet nozzle 10 for the fluid to be cooled by a metering valve 12 dominated, wherein the fluid to be cooled, for example, an exhaust gas, so that the outlet nozzle 10 dominant valve 12 is designed as an EGR valve, which in turn via an adjusting device 13 is pressed, which is also on the outer shell 2 the cooling device 1 is attached.

The structure of the actual cooling device 1 with the heat exchanger element 3 in particular 2 can be seen, in which the heat exchanger element 3 as well as the outer shell 2 cut open and without lid 5 are shown. It can be clearly seen that one on the heat exchanger element 3 trained plate 14 the outer shell 2 closes at its open side. Furthermore, it can be seen that parallel to the main flow direction z through an intermediate wall 15 separated, in the outer shell 2 a bypass channel 16 is formed, over which the heat exchanger element 3 is bypassable. Also this bypass channel is through the plate 14 locked. Furthermore, it is clear in this view that in the outer shell 2 between the in the main flow direction z extending Wärmetau shear element 3 as well as the partition 15 or the outer wall 17 the outer shell 2 an exhaust leading channel 18 is trained. In this exhaust gas leading channel 18 also protrude in the main flow direction z extending longitudinal ribs 19 ,

The coolant flowed through the channel 4 except at its open, through the lid 5 closed side completely by the integrally produced by die casting heat exchanger element 3 educated. This heat exchanger element 3 has two side walls extending in the main flow direction z 20 . 21 on that the channel 4 limit in its width and from which transverse ribs 22 in the coolant flow channel 4 extend. These ribs 22 stand perpendicular to the side walls 20 . 21 , wherein seen in the main flow direction z alternately from each side wall 20 . 21 one rib each 22 extends, which extends over the entire height of the relevant side wall 20 . 21 the coolant flowed through the channel 4 extends and extends in the extension direction at least over half the width of the channel 4 extends. It follows that the cross section of the channel 4 at least halfway through each rib 22 is closed.

This will also come from the 3 clearly, being in the 3 both the lid 5 , which flowed through the coolant channel 4 closes, partially cut away is shown, as well as a front wall in this view of the outer shell 2 the cooling device 1 , As a result, the internal structure of the cooling device 1 visible, so that both the bypass flap 9 as well as the metering valve 12 can be seen in this illustration. The metering valve 12 is designed as a poppet valve whose valve seat in the region of the connection point between outlet nozzle 10 and outer shell 2 is arranged and thus controls the total mass flow of the fluid to be cooled. Advantageously, the metering valve is 12 to a plug valve, which in the assembled state in the outer shell 2 is inserted and on the outer shell 2 is attached. The bypass flap 9 is designed as eccentrically mounted on a shaft flap whose drive shaft through the lid 5 ranges and there over an eccentric 23 and a ball joint 24 with an operating rod 25 the vacuum box 7 connected is.

Furthermore, it can be seen that in the flow direction behind the finned coolant channel leading 4 a secondary channel 26 is arranged, in the outlet nozzle 11 flows and over the bypass flap 9 and the metering valve 12 to be bypassed.

The following is the operation of the cooling device 1 explained in detail using the example of an insert as an exhaust gas cooler.

When the internal combustion engine starts cold, recirculated exhaust gas reaches the cooling device via the exhaust gas inlet connection 1 , Since during cold start of the internal combustion engine, the bypass damper 9 the exhaust gas leading channel 18 closes, the exhaust gas flows through the bypass channel 16 without being cooled. The exhaust gas mass flow is simultaneously via the position of the flow direction behind the heat exchanger element 3 arranged exhaust gas recirculation valve 1 regulated. By returning the warm uncooled exhaust gas, the internal combustion engine is heated quickly, at the same time the warm exhaust gas in the channel 18 in front of the bypass flap 9 stands and also contributes to the coolant heating.

After the internal combustion engine has warmed up, the bypass flap becomes 9 by switching the solenoid valve 8th and thus the vacuum box 7 switched over so that now the bypass channel 16 is closed and the exhaust gas permeable channel 18 is open. Through the longitudinal ribs 19 in the exhaust gas flowed through channel 18 create a good heat transfer and good cooling of the exhaust gas. The recirculated exhaust gas amount is further determined by the position of the exhaust gas recirculation valve 12 certainly.

During the entire period, coolant is supplied through the inlet port 6 in the coolant flow channel 4 pumped and there in serpentine lines between the cross ribs projecting into the cross section 22 directed. By the arrangement of the transverse ribs 22 creates a significantly increased residence time of the coolant in the channel 4 , so that a very good heat transfer to the exhaust gas is achieved. This is achieved both by the longer residence time and by the ribbing itself, which provides more surface area for heat exchange.

Now is the distance between the ribs 22 with each other and the ribs 22 and the side walls 20 . 21 especially low, this results in a higher pressure loss in the coolant flow channel 4 , It becomes clear that an adjustment of the pressure loss in this channel 4 Thus, only by the position of the ribs can be reached each other. However, care should be taken to ensure that the cross-section through which it flows remains as constant as possible. Subsequently, the coolant flows over the channel 26 to the outlet nozzle 11 , Depending on the required exhaust gas temperature and the amount of exhaust gas, the bypass flap 9 and the exhaust gas recirculation valve 12 controlled, with an optimization of the temperature and thus a significant reduction of the emitted pollutants in the engine he is enough.

It is clear that such a heat exchanger element and such a cooling device with outer shell and heat exchanger element can be produced in the die casting process, so that the assembly costs and the production costs are reduced. For fixing these components with each other, a friction stir welding method is preferably used. An adjustment of the pressure loss in the cooling channel 4 by adapting the diecasting tool and thus arranging the transverse ribbing accordingly 22 is possible without having to adapt the heat exchanger in its other form. In comparison with known designs, an optimization of the heat transfer is thus achieved with simple production and thus small designs can be used.

It It should be clear that the cross ribbing formed differently can be. Decisive is the positive guidance of the coolant under extension which flowed through Route, as well as the flow the ribs. For example, a forcibly guided serpentine up and down is also included Abbewegung by a corresponding ribbing conceivable.

It should also be clear that any attachments such as bypass flap or metering valve or actuators be designed differently can or the cooling device used individually. Even a different arrangement of the and outlets is certainly conceivable.

Claims (9)

Cooling device for internal combustion engines with an outer shell, in which a die-cast heat exchanger element is used, wherein between the heat exchanger element and the outer shell a through-flow of a fluid to be cooled channel is arranged and in the heat exchanger element, a coolant flow channel is formed by the main flow direction extending side walls is limited, characterized in that in the main flow direction (z) alternately from two opposite side walls ( 20 . 21 ) of the coolant flow channel ( 4 ) of the heat exchanger element ( 3 ) Ribs ( 22 ) perpendicular to the main flow direction (z) in the channel ( 4 ), wherein the cross-section to the main flow direction (z) of the channel ( 4 ) through each rib ( 22 ) is completely closed over the height of the side wall and in the extension direction of each rib ( 22 ) is at least half closed. Cooling device for internal combustion engines according to claim 1, characterized in that the flow-through cross section of the coolant flow channel ( 4 ) between the ribs ( 22 ) and between the ribs ( 22 ) and the side walls ( 20 . 21 ) is substantially constant Cooling device for internal combustion engines according to claim 1 or 2, characterized in that the ribs ( 22 ) have a continuously shrinking in the direction of extension cross-sectional width. Cooling device for internal combustion engines according to one of the preceding claims, characterized in that the heat exchanger element ( 3 ) at its channel to be cooled by the fluid to be cooled ( 18 ) facing side in the direction of flow ribs ( 19 ) having. Cooling device for internal combustion engines according to one of the preceding claims, characterized in that the channel to be cooled by the fluid to be cooled ( 18 ) through the heat exchanger element ( 3 ) is closed. Internal combustion engine cooling device according to one of the preceding claims, characterized in that the coolant flow channel ( 4 ) is closed by a lid. Cooling device for internal combustion engines according to one of the preceding claims, characterized in that the connections between the outer shell ( 2 ) and heat exchanger element ( 3 ) and heat exchanger element ( 3 ) and lid ( 5 ) are produced by friction stir welding. Cooling device for internal combustion engines according to one of the preceding claims, characterized in that in the outer shell ( 2 ) of the cooling device ( 1 ) an intermediate wall ( 15 ) is formed, which can be flowed through by the fluid to be cooled channel ( 18 ) from a bypass channel ( 16 ), whereby the bypass channel ( 16 ) and the channel to be cooled by the fluid to be cooled ( 18 ) by means of a bypass flap ( 9 ) are switched on and off. Cooling device for internal combustion engines according to claim 8, characterized in that the bypass flap ( 9 ) and a metering valve ( 12 ) in the outer shell ( 2 ) of the cooling device ( 1 ) are arranged.