DE102021116217A1 - Exhaust gas cooler for cooling exhaust gas from an internal combustion engine and a drive device with an internal combustion engine and a method for operating a drive device - Google Patents

Abstract

The invention relates to an exhaust gas cooler (1) for cooling exhaust gas from an internal combustion engine (18), having an inlet area (2) for supplying the exhaust gas, an outlet area (3) for discharging the exhaust gas and an area between the inlet area (2) and the outlet area ( 3) present cooling area (4), wherein the cooling area (4) has a plurality of cooling ducts (5) through which the exhaust gas flows at least at times and around which a coolant flows at least at times to cool the exhaust gas. It is provided that the inlet area (2) and the outlet area (3) via a first flow path, which runs through at least one first of the cooling ducts (5), and via a second flow path, which runs through at least a second of the cooling ducts (5). , are fluidically connected to one another, a first flow cross-sectional area of the first flow path being constant and a second flow cross-sectional area of the second flow path being adjustable by means of an adjusting device (15). The invention also relates to a drive device (17) with an internal combustion engine (18) and a method for operating a drive device (17) with an internal combustion engine (18).

Description

The invention relates to an exhaust gas cooler for cooling exhaust gas from an internal combustion engine, having an inlet area for supplying the exhaust gas, an outlet area for discharging the exhaust gas and a cooling area between the inlet area and the outlet area, the cooling area having a plurality of cooling channels through which the exhaust gas flows at least at times has, which are flowed at least temporarily by a coolant to cool the exhaust gas. The invention further relates to a drive device with an internal combustion engine and a method for operating a drive device with an internal combustion engine.

From the prior art, for example, the publication WO 2005/111385 A2 famous. This describes a heat exchanger for internal combustion engines, comprising a first, elongated flow channel for the passage of exhaust gases from the internal combustion engine, a second flow channel arranged adjacent to the first flow channel for the passage of the exhaust gases, a line separate from the second flow channel for the passage of a medium, in particular a coolant, wherein thermal energy can be exchanged between the exhaust gas of the second flow channel and the medium of the line, and wherein thermal energy can be exchanged between the exhaust gas in the first flow channel and the medium in the line, at least not to a significant extent, and a valve channel with an adjustable valve element, wherein by a position of the valve element, a distribution of the exhaust gases to the first flow channel and the second flow channel can be adjusted. A heat exchanger, which is particularly advantageous in terms of the required installation space and the exhaust gas routing, is created in that an inlet-side flow axis of the valve channel has a different direction than a flow axis of the first flow channel.

The pamphlet WO 2008/031959 A1 describes an exhaust gas recirculation circuit arranged between an exhaust manifold and an intake air manifold of a supercharged engine, with an exhaust gas recirculation control means arranged between the exhaust manifold and an exhaust gas cooler. It is provided that the circuit has an interrupting means for at least partially interrupting the circuit, the interrupting means being arranged between an inlet connection of the exhaust gas cooler and the inlet air distributor.

It is the object of the invention to propose an exhaust gas cooler for cooling exhaust gas from an internal combustion engine, which has advantages over known exhaust gas coolers, in particular making efficient use of the available installation space.

According to the invention, this is achieved with an exhaust gas cooler for cooling an internal combustion engine with the features of claim 1 . It is provided that the inlet area and the outlet area are fluidically connected to one another via a first flow path, which runs through at least one first of the cooling ducts, and via a second flow path, which runs through at least a second of the cooling ducts, with a first flow cross-sectional area of the first Flow path constant and a second flow cross-sectional area of the second flow path can be adjusted by means of an adjusting device.

Advantageous configurations with expedient developments of the invention are specified in the dependent claims.

The exhaust gas cooler is used to cool exhaust gas from an internal combustion engine, which is part of a drive device in particular. The drive device is used, for example, to drive a motor vehicle, in this respect therefore to provide a drive torque aimed at driving the motor vehicle. The drive torque is provided at least temporarily by the internal combustion engine, which for this purpose is drivingly coupled or can be coupled to an output shaft of the drive device. The drive device or the internal combustion engine are preferably part of the motor vehicle. During operation of the internal combustion engine, fresh gas, in particular air, and fuel are supplied to it. The fresh gas and the fuel form a mixture that is burned in a combustion chamber of a cylinder of the internal combustion engine. The combustion of the mixture produces the exhaust gas, which is discharged to the outside environment via an exhaust system.

The exhaust gas is fed to the exhaust gas cooler at least temporarily. In particular, all of the exhaust gas generated by the internal combustion engine is fed to the exhaust gas cooler. The exhaust gas cooler has the inlet area for supplying the exhaust gas. In this respect, the exhaust gas is fed at least partially, preferably completely, to the inlet area of the exhaust gas cooler. The inlet area has a corresponding inlet opening through which the exhaust gas enters the inlet area. Furthermore, the exhaust gas cooler has the outlet area for discharging the exhaust gas. The outlet area has a corresponding outlet opening through which the exhaust gas emerges from the outlet area.

The cooling area is in terms of flow between the inlet area and the outlet area, so that the inlet area and the outlet area are connected to one another in terms of flow or are connected to one another in terms of flow via the cooling area. The cooling area has the plurality of cooling channels. The cooling channels are, for example, in the form of pipelines that have a rectangular or circular cross-sectional area. The cooling ducts are preferably configured identically to one another, ie preferably have identical dimensions and/or a mutually identical shape, so that the cooling ducts are present as a plurality of identically dimensioned and/or designed cooling ducts.

The coolant flows at least temporarily against and/or around the cooling channels. This means that an outer peripheral surface of the cooling channels is acted upon by the coolant. This results in a heat transfer between the cooling channels and the coolant, in particular heat is transferred from the cooling channels into the coolant. All cooling channels are preferably acted upon by the coolant. In this respect, the cooling region has a cooling jacket which surrounds the plurality of cooling channels and through which the coolant flows at least at times.

In terms of flow, the cooling channels are arranged between the inlet area and the outlet area. In this respect, the inlet area and the outlet area are fluidically connected to one another via the cooling channels. The cooling channels preferably start directly from the inlet area on the one hand and open directly into the outlet area on the other hand. The exhaust gas supplied to the inlet area can thus flow through the cooling channels into the outlet area. In this respect, the exhaust gas flows through the cooling channels at least at times. During the flow through the cooling channels, a corresponding heat transfer takes place from the exhaust gas into the coolant, which leads to a corresponding reduction in an exhaust gas temperature of the exhaust gas and thus to its cooling.

The invention provides that the inlet area and the outlet area are fluidically connected to one another via the first flow path and the second flow path. It is provided that the first flow path runs through the at least one first of the cooling channels, while the second flow path runs through the at least one second of the cooling channels. In principle, the exhaust gas can flow from the inlet area into the outlet area at least at times both via the first flow path and the second flow path. Here, the exhaust gas flows through the first cooling channel or the second cooling channel. There is no flow connection between the first cooling duct and the second cooling duct itself; rather, the first cooling duct and the second cooling duct are fluidically connected to one another only via the inlet area or the outlet area.

It should be noted that the first flow path and the second flow path do not mean that the respective flow path runs exclusively through one of the cooling channels, namely either through exactly one first cooling channel or through exactly one second cooling channel. Rather, the first flow path preferably includes a plurality of the cooling ducts, which are then referred to as first cooling ducts, while the second flow path also includes a plurality of cooling ducts, which are then referred to as second cooling ducts.

In other words, the exhaust gas can flow from the inlet area along the first flow path into the outlet area, with the exhaust gas flowing through the first cooling channels. Additionally or alternatively, the exhaust gas can flow along the second flow path from the inlet area into the outlet area, with it correspondingly flowing through the second cooling channels. Preferably, only the first and second flow paths are present, so that each of the cooling channels is assigned to exactly one of the two flow paths. In other words, the cooling channels are divided between the two flow paths, so that the cooling channels are divided exclusively into first cooling channels and second cooling channels.

The first flow path has the first flow cross-sectional area and the second flow path has the second flow cross-sectional area. The first through-flow cross-sectional area is to be understood as that through-flow cross-sectional area that is present between the inlet area and the outlet area across the first flow channel. It therefore represents the smallest through-flow cross-sectional area over the course of the first flow channel between the inlet area and the outlet area. The situation is analogous for the second through-flow cross-sectional area.

The first through-flow cross-sectional area is constant over time and the second through-flow cross-sectional area can be adjusted by means of the adjusting device. Thus, only the second through-flow cross-sectional area can be adjusted, namely by means of the adjusting device. The adjusting device enables a throughput to be set, i.e. a mass flow or a volume flow, of the exhaust gas flowing along the second flow path. In this respect, the adjustment device can be used to set a distribution of the exhaust gas over the first flow path and the second flow path.

The adjusting device preferably has at least one first position and one second position, the second flow cross-sectional area having a smaller first value in the first position and a larger second value in the second position. The second flow cross-sectional area is particularly preferably equal to zero in the first position of the adjusting device, while the second flow cross-sectional area in the second position corresponds to a maximum possible value of the second flow cross-sectional area. The second flow path is therefore completely interrupted in the first position and completely released in the second position. The adjusting device is preferably arranged in the inlet area. The second flow path is thus interrupted upstream of the cooling ducts, so that when the second flow path is completely interrupted, the exhaust gas cannot get into the corresponding cooling ducts. Alternatively, the adjusting device is arranged in the outlet area or in the cooling area, so that the second flow path is interrupted in the cooling channels or downstream of the cooling channels.

Adjusting the second through-flow cross-sectional area adjusts a cooling capacity of the exhaust gas cooler. For example, the first position of the adjusting device is present during operation of the exhaust gas cooler with a reduced cooling capacity, while the second position of the adjusting device is used during operation of the exhaust gas cooler with a higher, in particular maximum, cooling capacity. In particular, the invention makes the use of a bypass to circumvent the cooling channels to reduce the cooling capacity superfluous, as a result of which a particularly compact exhaust gas cooler is created. The exhaust gas cooler according to the invention can thus be mounted on an internal combustion engine in a particularly space-saving manner.

A further development of the invention provides that the inlet area has a first sub-area assigned to the first flow path and a second sub-area assigned to the second flow path, the first sub-area and the second sub-area being fluidically connected to one another via a passage opening having the second flow cross-sectional area. Preferably, the exhaust gas initially enters the first partial area through the inlet opening of the inlet area. The first sub-area opens into the first cooling channels on the one hand and into the second sub-area via the through-opening on the other.

The second partial area opens into the second cooling channels. Thus, the exhaust gas that has entered the first partial area can flow either directly along the first flow path or via the second partial area along the second flow path in the direction of the outlet area. The passage opening has the second flow cross-sectional area. To this extent, the second through-flow cross-sectional area can be adjusted by changing the dimensions of the through-opening. This enables a particularly space-saving arrangement.

A development of the invention provides that the adjusting device comprises an adjusting element arranged at the through-opening, which is rotatably mounted about an axis of rotation arranged parallel to the second through-flow cross-sectional area for adjusting the second through-flow cross-sectional area. The actuating element is, for example, in the form of a rotatable flap. The flap at least partially overlaps the passage opening in at least one position, so that it is at least partially closed. The adjusting element preferably completely closes the passage opening in the first position of the adjusting device. In the second position of the adjusting device, however, the adjusting element releases the passage opening at least partially. In particular, the actuating element is arranged at a first angle of rotation with respect to the passage opening in the first position and at a second angle of rotation in the second position.

The actuating element is particularly preferably arranged on a side of the passage opening which faces the second partial area. As a result, the actuating element pivots at least partially in the direction of the second partial region when it is shifted from the closed position into the open position. Of course, in addition to the first position and the second position, any further positions of the actuating element can be present. For example, the actuating element can be continuously adjusted between the first position and the second position, with the second flow cross-sectional area being correspondingly continuously adjustable. This creates a functionally versatile adjusting device in a simple manner.

The invention also relates to a drive device with an internal combustion engine, in particular with an exhaust gas cooler according to the statements in this description, wherein an exhaust gas generated by the internal combustion engine can be fed back into the internal combustion engine at least temporarily via an exhaust gas recirculation device is, wherein the exhaust gas recirculation device comprises the exhaust gas cooler for cooling the recirculated exhaust gas, which has an inlet area for supplying the recirculated exhaust gas, an outlet area for discharging the recirculated exhaust gas and a cooling area present between the inlet area and the outlet area, the cooling area having a plurality of at least at times has cooling ducts through which the exhaust gas flows, around which a coolant flows at least at times in order to cool the exhaust gas. It is provided that the inlet area and the outlet area are fluidically connected to one another via a first flow path, which runs through at least one first of the cooling ducts, and via a second flow path, which runs through at least a second of the cooling ducts, with a first flow cross-sectional area of the first Flow path constant and a second flow cross-sectional area of the second flow path can be adjusted by means of an adjusting device.

The advantages of such a procedure or such a configuration of the exhaust gas cooler have already been pointed out. Both the exhaust gas cooler and the drive device can be further developed according to the explanations within the scope of this description, so that reference is made to them in this respect.

The exhaust gas generated by the internal combustion engine can contain pollutants that are subject to strict emission limits. In particular, the exhaust gas can contain nitrogen oxides. Exhaust gas recirculation is provided to reduce pollutant emissions, in particular to reduce emissions of nitrogen oxides. For this purpose, the drive device or the internal combustion engine has the exhaust gas recirculation device, by means of which the exhaust gas generated by the internal combustion engine can be at least partially returned to the internal combustion engine. The exhaust gas recirculation device is designed to feed part of the exhaust gas generated by the internal combustion engine back to the internal combustion engine, namely together with the fresh gas. In this respect, the mixture present in the combustion chamber of the cylinder can, in addition to the fresh gas and the fuel, have exhaust gas that is recirculated at least at times.

In order to avoid or at least reduce heat being introduced into the mixture by the recirculated exhaust gas, the exhaust gas recirculation device has the exhaust gas cooler. This serves to cool the recirculated exhaust gas. To this end, the exhaust gas to be returned is fed to the exhaust gas cooler before it is returned to the internal combustion engine. In the exhaust gas cooler, the exhaust gas is at least temporarily cooled by means of the coolant. As already explained above, the cooling capacity of the exhaust gas cooler can be adjusted by means of the adjusting device. By using the exhaust gas cooler according to the invention, a drive device with a particularly compact and efficient exhaust gas recirculation device is created.

A further development of the invention provides an exhaust gas turbocharger with a turbine and a compressor, the recirculated exhaust gas being able to be removed downstream of the turbine and fed back into an intake line of the internal combustion engine upstream of the compressor. In this respect, the internal combustion engine is a supercharged internal combustion engine with low-pressure exhaust gas recirculation. The exhaust gas generated by the internal combustion engine first flows through the turbine, which is connected to the compressor in terms of drive technology. The compressor is used to compress the fresh gas supplied to the internal combustion engine, as a result of which an increase in the power of the internal combustion engine is achieved.

It is advantageous to extract the recirculated exhaust gas downstream of the turbine, since the amount of exhaust gas flowing through the turbine is not reduced by the extraction of the recirculated exhaust gas. As a result, the efficiency of the exhaust gas turbocharger can be improved. However, since the exhaust gas is already being cooled during the expansion work performed in the turbine, condensation of water vapor contained in the exhaust gas can occur in the exhaust gas cooler if the recirculated exhaust gas is cooled further. This water vapor can damage the compressor. Furthermore, instabilities in the combustion of the mixture in the cylinder can occur due to excessive cooling of the recirculated exhaust gas. These disadvantageous effects occur in particular when the drive device has not yet reached its operating temperature.

In order to avoid this, provision could now be made to prevent the exhaust gas recirculation until the drive device has reached its operating temperature. However, this is associated with an increase in emissions, particularly nitrogen oxides, as long as exhaust gas recirculation does not take place. Alternatively, it could be provided to bypass the exhaust gas cooler by means of a bypass. As a result, the exhaust gas recirculation can be carried out without cooling the recirculated exhaust gas. By using the exhaust gas cooler according to the invention, on the other hand, the use of such a bypass can be dispensed with and the exhaust gas can still be recirculated, since the second through-flow can be achieved by means of the actuating device cross-sectional area and thus the cooling capacity of the exhaust gas cooler can be adjusted.

Additionally or alternatively, it can be provided that the recirculated exhaust gas is removed upstream of the turbine and recirculated downstream of the compressor. In this respect, this is a high-pressure exhaust gas recirculation. Here, in particular during a cold start of the drive device, the above-described condensation of the water vapor contained in the exhaust gas can occur. By using the exhaust gas cooler according to the invention, analogous to the low-pressure exhaust gas recirculation explained above, the use of a bypass in the high-pressure exhaust gas recirculation can be dispensed with.

The invention also relates to a method for operating a drive device with an internal combustion engine, in particular a drive device according to the statements made within the scope of this description, wherein an exhaust gas generated by the internal combustion engine is at least partially recirculated into the internal combustion engine via an exhaust gas recirculation device, the exhaust gas recirculation device using the exhaust gas cooler for cooling of the recirculated exhaust gas, which has an inlet area for supplying the recirculated exhaust gas, an outlet area for discharging the recirculated exhaust gas and a cooling area between the inlet area and the outlet area, wherein the cooling area has a plurality of cooling channels through which the exhaust gas flows at least at times, which for Cooling of the exhaust gas are at least temporarily flowed around by a coolant.

It is provided that the inlet area and the outlet area are fluidically connected to one another via a first flow path, which runs through at least one first of the cooling ducts, and via a second flow path, which runs through at least a second of the cooling ducts, with a first flow cross-sectional area of the first Flow path constant and a second flow cross-sectional area of the second flow path can be adjusted by means of an adjusting device, the second flow cross-sectional area being reduced during a warm-up operation of the drive device and increased in normal operation following the warm-up operation.

With regard to the advantages and possible advantageous configurations, reference is once again made to the explanations within the scope of this description.

The invention provides at least two modes of operation of the drive device, namely warm-up mode and normal mode. The warm-up operation and the normal operation differ with regard to a setting of the second flow cross-sectional area and thus with regard to the cooling capacity provided by the exhaust gas cooler. In the warm-up operation, the second through-flow cross-sectional area is reduced by means of the actuating element. In this respect, there is a reduced cooling capacity of the exhaust gas cooler during the warm-up operation. During the warm-up operation, the above-described condensation of the water vapor contained in the recirculated exhaust gas can be avoided since the exhaust gas cooler is only operated with the reduced cooling capacity.

The warm-up operation of the drive device is preferably carried out as long as the drive device has not yet reached its operating temperature, ie its temperature is lower than the operating temperature. The actuating element of the actuating device is particularly preferably in the closed position during the warm-up operation. In this case, the recirculated exhaust gas can only flow through the exhaust gas cooler via the first flow path during the warm-up operation.

Normal operation follows warm-up operation. Normal operation is carried out as soon as the temperature of the drive device has reached the operating temperature or is equal to or greater than this. Under this condition, there is a switchover from the warm-up mode to the normal mode. In normal operation, the second through-flow cross-sectional area is increased by means of the actuating element. In this respect, there is a greater cooling capacity of the exhaust gas cooler during normal operation compared to the warm-up operation. Normal operation is preferably carried out as soon as the drive device reaches or exceeds its operating temperature. The actuating element of the actuating device is particularly preferably in the open position during normal operation. In this case, the recirculated exhaust gas can flow through the exhaust gas cooler during normal operation both along the first flow path and along the second flow path.

In addition, it can be provided that normal operation is switched back to warm-up operation if the temperature of the drive device falls below the operating temperature during normal operation. This can be done, for example, during an idling phase of the drive device, in which the internal combustion engine is at least temporarily decoupled in terms of drive technology from the output shaft of the drive device and is not operated to provide the drive torque, or during overrun operation Drive device, in which the internal combustion engine is at least temporarily coupled to the output shaft in terms of drive technology without a supply of fuel, may be the case. A hysteresis is preferably provided when switching over as a result of exceeding or falling below the operating temperature.

A further development of the invention provides that after starting the internal combustion engine, the warm-up operation takes place first and when an exhaust gas temperature of the recirculated exhaust gas exceeds a first temperature threshold value, a switch is made from the warm-up operation to normal operation. In this respect, after starting the internal combustion engine, the exhaust gas cooler is initially operated with the reduced cooling capacity. During the warm-up operation, the drive device, in particular the internal combustion engine, will heat up towards its operating temperature. In this case, the exhaust gas temperature in particular will rise.

It is provided that when the exhaust gas temperature exceeds the first temperature threshold value, the system switches from the warm-up mode to the normal mode. The first temperature threshold value preferably corresponds to the operating temperature of the drive device. Of course, provision can also be made for switching over to normal operation before the drive device has reached the operating temperature. In this case, the first temperature threshold is less than the operating temperature. The first temperature threshold value particularly preferably corresponds to an exhaust gas temperature at which the above-explained condensation of the water vapor is no longer to be expected, for example it is slightly greater than this temperature. This procedure creates a particularly efficient drive device.

A further development of the invention provides that the second flow cross-sectional area is initially set to a smaller first value after switching to normal operation and, when the exhaust gas temperature exceeds a second temperature threshold value, in the direction of a larger second value, with the second temperature threshold value being greater than the first temperature threshold. In this respect, the second temperature threshold value is present in addition to the first temperature threshold value. When the exhaust gas temperature exceeds the first temperature threshold value, the system switches to normal operation and the second flow cross-sectional area is set to the first value. In this case, the actuating element of the actuating device is preferably only partially displaced in the direction of the open position, so that the second flow cross-sectional area corresponds to the first value.

During normal operation, the actuating element is then moved further in the direction of the open position. In this case, the actuating element is adjusted as a function of the exhaust gas temperature, so that the second flow cross-sectional area increases in the direction of the second value as the exhaust gas temperature rises. The second value particularly preferably corresponds to the open position of the actuating element. In other words, after switching over to normal operation, the actuating element is initially not completely displaced into the open position, but only partially in the direction of the open position. The actuating element should only be in the open position when the second temperature threshold value is exceeded. This procedure allows the cooling performance of the exhaust gas cooler to be optimized during normal operation.

A development of the invention provides that the drive device comprises an exhaust gas back pressure valve for setting an exhaust gas back pressure, with a manipulated variable of the exhaust gas back pressure valve being adjusted during the warm-up operation as a function of a pressure loss occurring via the first flow path and/or via the second flow path, so that a constant exhaust gas mass flow is achieved via the first flow path and/or the second flow path. The exhaust gas back pressure is a pressure of the exhaust gas present downstream of the internal combustion engine, in particular downstream of the turbine, compared to the pressure of the fresh gas present upstream of the internal combustion engine. The exhaust gas flows under the exhaust gas back pressure into the inlet area of the exhaust gas cooler, so that the exhaust gas back pressure has a significant influence on the mass flow or the volume flow of the recirculated exhaust gas.

The exhaust gas back pressure valve is used to set the exhaust gas back pressure and is arranged, for example, downstream of an exhaust gas aftertreatment device. Additionally or alternatively, the exhaust gas back pressure valve is arranged downstream of the exhaust gas cooler, in particular it is integrated into the outlet area of the exhaust gas cooler. The exhaust gas mass flow of the recirculated exhaust gas can be adjusted by means of the exhaust gas back pressure valve. For this purpose, the manipulated variable of the exhaust back pressure valve is adjusted accordingly.

In addition to the exhaust back pressure valve, however, the exhaust gas mass flow is also influenced by the actuating element in the inlet area of the exhaust gas cooler. When flowing through the exhaust gas cooler, the recirculated exhaust gas experiences the pressure reduction desire. The pressure loss is to be understood in particular as a pressure difference of the recirculated exhaust gas between the inlet area and the outlet area of the exhaust gas cooler.

If the second flow cross-sectional area is reduced, the pressure loss across the exhaust gas cooler increases accordingly. This can lead to a reduction in the exhaust gas mass flow, so that in the warm-up operation there would be a reduced exhaust gas mass flow compared to normal operation. In order to avoid this, provision is made for compensating for the pressure loss by adjusting the manipulated variable of the exhaust back pressure valve. In this case, the manipulated variable is preferably set in such a way that during the warm-up operation there is an exhaust gas mass flow which corresponds to an exhaust gas mass flow in normal operation. This procedure ensures that the emission benefits of exhaust gas recirculation can be fully utilized during warm-up operation.

Finally, a development of the invention provides that during the warm-up operation, a coolant supply of the coolant is at least temporarily reduced, in particular completely prevented. As already explained above, the exhaust gas cooler is operated with the reduced cooling capacity during the warm-up operation. In order to further lower the cooling performance during the warm-up operation, the coolant supply of the coolant is reduced. In particular, provision can be made for the coolant supply to be completely interrupted at least temporarily during the warm-up operation. As a result, the cooling capacity of the exhaust gas cooler can be reduced to a minimum, at least temporarily, during the warm-up operation.

The features and feature combinations described in the description, in particular the features and feature combinations described in the following description of the figures and/or shown in the figures, can be used not only in the combination specified in each case, but also in other combinations or on their own, without going beyond the scope of the leave invention. The invention is therefore also to be regarded as encompassing embodiments which are not explicitly shown and explained in the description and/or the figures, but emerge from the explained embodiments or can be derived from them.

• 1 einen Abgaskühler in einer ersten Schaltstellung einer Stellvorrichtung,
• 2 den Abgaskühler in einer zweiten Schaltstellung der Stellvorrichtung, und
• 3 eine schematische Darstellung einer Antriebseinrichtung mit dem Abgaskühler.

The invention is explained in more detail below with reference to the exemplary embodiments illustrated in the drawing, without the invention being restricted. It shows:

• 1 an exhaust gas cooler in a first switching position of an actuating device,
• 2 the exhaust gas cooler in a second switching position of the actuating device, and
• 3 a schematic representation of a drive device with the exhaust gas cooler.

the 1 shows an exhaust gas cooler 1 for cooling exhaust gas of an internal combustion engine. The exhaust gas cooler 1 has an inlet area 2 for supplying the exhaust gas and an outlet area 3 for discharging the exhaust gas. Between the inlet area 2 and the outlet area 3 there is a cooling area 4 . A plurality of cooling channels 5 are arranged in the cooling area 4, via which the inlet area 2 and the outlet area 3 are fluidically connected to one another. The cooling channels 5 are, for example, in the form of pipelines with a rectangular or circular cross-sectional area. The exhaust gas can thus flow out of the inlet area 2 and the outlet area 3 through the cooling channels 5 .

The cooling area 4 has at least one coolant connection 6 for supplying a coolant which flows around the cooling channels 5 at least at times. As a result, the exhaust gas flowing through the cooling channels 5 is cooled at least temporarily. The exhaust gas cooler 1 shown has two coolant connections 6 , the coolant being supplied to the exhaust gas cooler 1 through a first of the two coolant connections 6 and being discharged through a second of the two coolant connections 6 . In this respect, the cooling area 4 has a cooling jacket that encompasses the cooling channels 5 .

The inlet area 2 comprises a first sub-area 7 and a second sub-area 8. The first sub-area 7 and the second sub-area 8 are fluidically connected to one another via a passage opening 9. The exhaust gas enters the first partial area 7 through an inlet opening 10 . From the first portion 7, the exhaust gas along a first flow path in the 1 represented by an arrow 11, flow in the direction of a longitudinal central axis 12 of the exhaust gas cooler 1 through at least a first of the cooling channels 5 into the outlet region 3. The exhaust gas then exits the outlet region 3 through an outlet opening 13 .

In addition to the first flow path, there is a second flow path that runs through at least a second one of the cooling channels 5 . Here, the exhaust gas flows from the first portion 7 through the passage opening 9 in the second portion 8 and from this into the second of the cooling channels 5. In the 1 the second flow path is represented by two arrows 14 .

The first flowpath has a first cross-sectional flow area that is constant is. The second flow path, on the other hand, has a second flow cross-sectional area that can be adjusted by means of an adjusting device 15 . In this case, the passage opening 9 has the second flow cross-sectional area. To set the second through-flow cross-sectional area, the adjusting device 15 has an adjusting element 16 which is designed in the form of a pivotable flap. The actuating element 16 is mounted such that it can rotate about an axis of rotation, so that the through-opening 9 can be closed by means of the actuating element 16 . In the 1 the actuating element 16 is in an open position, so that the passage opening 9 is not closed. Accordingly, when the actuating element 16 is in the open position, the exhaust gas can flow through all of the cooling channels 5 . In principle, the actuating element 16 can alternatively to that in the 1 shown flap can also be in the form of a slide or a throttle device, which is suitable for adjusting the second flow cross-sectional area.

the 2 shows the exhaust gas cooler 1 in a closed position of the actuating element 16. In the closed position, the exhaust gas can only flow through the first flow path. Accordingly, when the actuating element 16 is in the closed position, the exhaust gas cooler 1 is operated with a reduced cooling capacity compared to the open position.

It should be noted that in the presentation of 1 and 2 the first flow path comprises only one of the cooling channels 5, while the second flow path comprises two of the cooling channels 5. In principle, there can be any number of cooling channels 5 in the first flow path and any number of cooling channels 5 in the second flow path. According to the invention, however, each of the cooling channels 5 is assigned to exactly one of the two flow paths.

The second through-flow cross-sectional area of the second flow path can basically be adjusted as desired between the closed position and the open position of the adjusting element 16 by means of the adjusting device 15 . In this respect, operation of the exhaust gas cooler 1 with a maximum cooling capacity is possible in the open position and operation of the exhaust gas cooler 1 with a minimum cooling capacity in the closed position. Additionally or alternatively, the actuating element 16 can only be partially displaced in the direction of the closed position, so that the cooling capacity of the exhaust gas cooler 1 can be adjusted as desired between the minimum cooling capacity and the maximum cooling capacity.

the 3 shows a schematic representation of a drive device 17 with an internal combustion engine 18 and an exhaust gas recirculation device 19. The drive device 17 has an exhaust gas turbocharger with a turbine 20 and a compressor 21. The exhaust gas generated by internal combustion engine 18 flows via turbine 20 into an exhaust system that has at least one exhaust gas aftertreatment device 22 . The turbine 20 is drivingly connected to the compressor 21 . Compressor 21 is used to supply fresh gas to internal combustion engine 18 , which is taken from the outside of drive device 17 via an intake line having an air filter 23 . In this case, the fresh gas fed to the internal combustion engine 18 is cooled by an intercooler 24 downstream of the compressor 21 .

By means of the exhaust gas recirculation device 19 , exhaust gas is at least temporarily removed from the exhaust system downstream of the turbine 20 and fed back upstream of the compressor 21 as recirculated exhaust gas into the intake line and thus into the internal combustion engine 18 .

The exhaust gas recirculation 19 has the exhaust gas cooler 1 for cooling the recirculated exhaust gas and an exhaust gas recirculation valve 25 . In this respect, the exhaust gas recirculation device 19 is a low-pressure exhaust gas recirculation. In addition to the exhaust gas recirculation device 19 , a high-pressure exhaust gas recirculation system is provided, which has a further exhaust gas cooler 25 and a further exhaust gas recirculation valve 27 .

During a warm-up operation of the drive device 17, the second flow cross-sectional area of the exhaust gas cooler 1 is reduced and increased in a normal operation following the warm-up operation. In particular, the actuating element 16 of the actuating device 15 is initially in the closed position after the internal combustion engine 18 has been started.

The exhaust gas recirculation valve 25 represents an exhaust gas back pressure valve. A manipulated variable of the exhaust gas recirculation valve 25 is adjusted as a function of a pressure loss occurring between the inlet area 2 and the outlet area 3 of the exhaust gas cooler 1 .

When an exhaust gas temperature of the recirculated exhaust gas exceeds a first temperature threshold value, the system switches from warm-up operation to normal operation. After switching to normal operation, the actuating element 16 is opened in the direction of the open position. Here, the manipulated variable of the exhaust gas recirculation valve 25 is further adapted to the pressure loss, so that a constant exhaust gas mass flow is achieved.

The invention creates a particularly compact exhaust gas cooler 1, the efficient Operation of the exhaust gas recirculation device 19 allows. In particular, the cooling capacity of the exhaust gas cooler 1 can be varied by adjusting the second flow cross-sectional area, without providing a bypass for at least temporarily bypassing the cooling channels 5 .

Reference List

1

exhaust gas cooler

2

entry area

3

outlet area

4

cooling area

5

cooling channels

6

coolant connection

7

first section

8th

second section

9

passage opening

10

intake port

11

arrow

12

longitudinal central axis

13

exhaust port

14

arrow

15

actuator

16

actuator

17

drive device

18

internal combustion engine

19

exhaust gas recirculation device

20

turbine

21

compressor

22

exhaust aftertreatment device

23

air filter

24

intercooler

25

exhaust gas recirculation valve

26

further exhaust gas cooler

27

another exhaust gas recirculation valve

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was 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.

Patent Literature Cited

• WO 2005/111385 A2 [0002]
• WO 2008/031959 A1 [0003]

Claims (10)

Exhaust gas cooler (1) for cooling exhaust gas of an internal combustion engine (18), with an inlet area (2) for supplying the exhaust gas and an outlet area (3) for discharging the exhaust gas and a cooling area between the inlet area (2) and the outlet area (3). (4), wherein the cooling area (4) has a plurality of cooling channels (5) through which the exhaust gas flows at least at times and around which a coolant flows at least at times to cool the exhaust gas, characterized in that the inlet area (2) and the outlet area (3) are fluidically connected to one another via a first flow path, which runs through at least a first one of the cooling channels (5), and via a second flow path, which runs through at least a second one of the cooling channels (5), with a first flow cross-sectional area of the first flow path constant and a second flow cross-sectional area of the second flow path by means of an adjusting device (15). is ellable. Exhaust gas cooler (1) after claim 1 , characterized in that the inlet area (2) comprises a first partial area (7) assigned to the first flow path and a second partial area (8) assigned to the second flow path, the first partial area (7) and the second partial area (8) having a die passage opening (9) having a second flow cross-sectional area are fluidically connected to one another. Exhaust gas cooler (1) according to one of the preceding claims, characterized in that the adjusting device (15) comprises an adjusting element (16) which is arranged on the through-opening (9) and which is rotatably mounted about an axis of rotation arranged parallel to the second cross-sectional flow area in order to adjust the second cross-sectional area of flow is. Drive device (17) with an internal combustion engine (18), in particular with an exhaust gas cooler (1) according to one or more of the preceding claims, wherein an exhaust gas generated by the internal combustion engine (18) is fed at least partially via an exhaust gas recirculation device (19) into the internal combustion engine (18) can be recirculated, wherein the exhaust gas recirculation device (19) comprises the exhaust gas cooler (1) for cooling the recirculated exhaust gas, which has an inlet area (2) for supplying the recirculated exhaust gas, an outlet area (3) for discharging the recirculated exhaust gas and an area between the inlet area (2 ) and the outlet area (3) has a cooling area (4), wherein the cooling area (4) has a plurality of cooling channels (5) through which the exhaust gas flows at least at times and around which a coolant flows at least at times to cool the exhaust gas, characterized that the inlet area (2) and the outlet area (3) via a first flow path through to at least one first of the cooling channels (5), and are fluidically connected to one another via a second flow path, which runs through at least a second of the cooling channels (5), a first flow cross-sectional area of the first flow path being constant and a second flow cross-sectional area of the second flow path being constant by means of a Adjusting device (15) is adjustable. Drive device (17) after claim 4 , characterized by an exhaust gas turbocharger with a turbine (20) and a compressor (21), wherein the recirculated exhaust gas can be removed downstream of the turbine (20) and upstream of the compressor (21) into an intake line of the internal combustion engine (18) can be returned. Method for operating a drive device (17) with an internal combustion engine (18), in particular a drive device (17) according to one or more of the preceding claims, wherein an exhaust gas generated by the internal combustion engine (18) is at least partially fed into the internal combustion engine via an exhaust gas recirculation device (19). (18) is recirculated, wherein the exhaust gas recirculation device (19) comprises the exhaust gas cooler (1) for cooling the recirculated exhaust gas, which has an inlet region (2) for supplying the recirculated exhaust gas, an outlet region (3) for discharging the recirculated exhaust gas and one between the inlet area (2) and the outlet area (3), the cooling area (4) having a plurality of cooling ducts (5) through which the exhaust gas flows at least at times and around which a coolant flows at least at times in order to cool the exhaust gas , characterized in that the inlet area (2) and the outlet area (3) via a en first flow path, which runs through at least a first one of the cooling channels (5), and via a second flow path, which runs through at least a second one of the cooling channels (5), are fluidically connected to one another, with a first flow cross-sectional area of the first flow path being constant and a second Flow cross-sectional area of the second flow path can be adjusted by means of an adjusting device (15), the second flow cross-sectional area being reduced during a warm-up operation of the drive device (17) and increased in normal operation following the warm-up operation. procedure after claim 6 , characterized in that after the internal combustion engine (18) is started, the warm-up operation takes place first and when an exhaust gas temperature of the recirculated exhaust gas exceeds a first temperature threshold value, a switch is made from the warm-up operation to normal operation. procedure after claim 6 or 7 , characterized in that the second flow cross-sectional area after switching to normal operation is initially set to a smaller first value and when the exhaust gas temperature exceeds a second temperature threshold value in the direction of a larger second value, the second temperature threshold value being greater than the first temperature threshold value. Procedure according to one of Claims 6 until 8th , characterized in that the drive device (17) comprises an exhaust gas back pressure valve for adjusting an exhaust gas back pressure, with a manipulated variable of the exhaust gas back pressure valve depending on a pressure loss occurring via the first flow path and/or via the second flow path being adjusted during the warm-up operation, so that a constant exhaust gas mass flow is achieved via the first flow path and/or via the second flow path. Procedure according to one of Claims 6 until 9 , characterized in that during the warm-up operation a coolant supply of the coolant is at least temporarily reduced, in particular completely prevented.

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