Device and method for cooling an exhaust gas aftertreatment device

Abstract

The present invention relates to a device (10) for cooling an exhaust gas aftertreatment device (12). The device (10) has a coolant circuit (16), the coolant circuit having a cooling region (18) for heat transfer with the exhaust gas aftertreatment device (12), and at least one reflux preventer (20, 22). The at least one reflux preventer (20, 22) is arranged upstream and / or downstream of the cooling region (18) and is constructed and / or designed such that it opens when there is a change in the coolant volume in the cooling region (18) and / or in the section of the coolant circuit (16) located between the cooling region (18) and the at least one reflux preventer (20, 22), the volume change occurring below the boiling temperature of the coolant. Preferably, a natural circulation of the coolant in the coolant circuit (16) can thus be provided below the boiling temperature of the coolant.

Description

Field of the Invention

[0001] The present invention relates to a device and a method for cooling an exhaust gas aftertreatment device, preferably an additive metering device. Background Art

[0002] In order to reduce nitrogen oxide emissions of internal combustion engines, so-called SCR systems (English: selective catalytic reduction) can be used. In these systems, a reducing agent (such as an aqueous urea solution) can be conveyed into the exhaust gas via a metering system, and the reducing agent can be used to convert nitrogen oxides into non-toxic compounds in a subsequent process. Depending on the installation of the SCR system, temperature-sensitive components are directly located on components that guide hot exhaust gas. In order to avoid overheating of these components, these components must be cooled. This can be done, for example, by connecting to a coolant circuit (such as the coolant circuit of an internal combustion engine).

[0003] When the internal combustion engine is running, the coolant can be recirculated in the coolant circuit by the coolant pump of the internal combustion engine. In some cases, a long-lasting "reheating" may occur after the internal combustion engine is shut down, in which heat is strongly transferred from the exhaust gas components to the SCR components installed in the exhaust gas components. In order to avoid component damage and shortened service life, the SCR components must be cooled in some way even after shutdown during "reheating" when needed.

[0004] DE 10 2014 221 655 A1 discloses a metering module for introducing an operating material into a pipeline, wherein the metering module is connected to a coolant circuit to cool at least a part of the metering module as needed, and wherein a flow control device is arranged in the coolant circuit. The flow control device is a valve device that controls the inflow of coolant into the metering module and the outflow of coolant from the metering module, and the valve device consists of a valve installed in the metering module on the input side and a valve extending from the metering module on the output side. In the case of shutdown, after coolant evaporation occurs in the coolant conduit and thus pressure increases, it is ensured that the coolant is forced to flow through the metering module, whereby the coolant escapes through the valve in the flow path, and then new cooling water is sucked into the coolant conduit through the valve when the pressure drops.

[0005] The disadvantage of the system known from DE 10 2014 221 655 A1 may be insufficient cooling. Under specific boundary conditions, the coolant temperature may rise steadily, and thus the pressure may also rise steadily, and there is no pressure drop anymore before the allowable component temperature is exceeded. No continuous coolant flow is generated. Summary of the Invention

[0006] Therefore, the task underlying the present invention is to provide alternative and / or improved technologies for cooling an exhaust gas aftertreatment device.

[0007] This task is solved by the features described independently below. Advantageous extensions are illustrated in the solutions described later.

[0008] The present invention provides a device for cooling an exhaust gas aftertreatment device (such as an SCR exhaust gas aftertreatment device), preferably an additive metering device (such as a reducing agent metering device (such as a reducing agent injector)). The device has a coolant circuit for guiding a coolant. The coolant circuit has a cooling area (for example, having cooling coils and / or heat exchangers) for heat transfer with the exhaust gas aftertreatment device. The coolant circuit has at least one reflux preventer, preferably a check valve. The at least one reflux preventer is arranged upstream and / or downstream of the cooling area and is constructed and / or designed such that when there is a change in the volume of the coolant (for example, without a phase change of the coolant and / or a periodic volume change with alternating volume increase and volume decrease) in the cooling area and / or in a section (preferably a cooling path section) of the coolant circuit located between the cooling area and the at least one reflux preventer (such as a pipe), the at least one reflux preventer (for example, already) opens, wherein the volume change occurs below the boiling temperature of the coolant. Thus, it is possible to preferably provide a suitably continuous or quasi - continuous natural circulation of the coolant in the coolant circuit below the boiling temperature of the coolant.

[0009] The device enables the exhaust gas aftertreatment device to be cooled with a coolant such as engine cooling water after the coolant pump in the coolant circuit is shut down. The device can be realized in a cost - advantageous manner and independently of pipe laying. For example, the circulation of the coolant can be ensured only by the temperature difference between the exhaust gas aftertreatment device / cooling area and the downstream section (such as a pipe) of the coolant circuit. The circulation here does not depend on whether the coolant in the cooling area boils. Instead, the circulation may already occur in a temperature range below the boiling temperature of the coolant. The volume change of the coolant that has occurred in this temperature range may be sufficient to enable the coolant to circulate through a reflux preventer with an appropriately adapted opening pressure. Specifically, for example, an increase in the volume of the coolant in the cooling area may cause the coolant to be pushed into the section downstream of the cooling area and appropriately pass through the reflux preventer here. The reflux preventer in the section upstream of the cooling area prevents the coolant from being forced to flow upstream. The coolant can also be cooled in the section downstream of the cooling area. A volume decrease occurs again, which ensures the re - suction of the coolant from the section upstream of the cooling area.

[0010] In one embodiment, the at least one reflux preventer suitably has a first reflux preventer, preferably a check valve, arranged upstream of the cooling zone, and / or suitably has a second reflux preventer, preferably a check valve, arranged downstream of the cooling zone, the second reflux preventer preferably being spaced apart from the cooling zone. The first reflux preventer allows the coolant to flow again but does not push the coolant back into the forward flow. The second reflux preventer enables the coolant to be discharged, but the coolant is not sucked back from the reflux. The spaced arrangement of the second reflux preventer may cause the section of the coolant circuit located between the cooling zone and the second reflux preventer to be used as a cooling path. In this section, the coolant previously heated in the cooling zone can be cooled, during which the coolant volume is reduced, thereby causing coolant from the forward flow to be sucked in.

[0011] In another embodiment, the first reflux preventer and / or the second reflux preventer is configured to have an opening pressure for opening the reflux preventer that is less than or equal to 10 mbar, preferably less than or equal to 1 mbar, particularly preferably less than or equal to 0.1 mbar or 0.05 mbar. Alternatively or additionally, the first reflux preventer and / or the second reflux preventer is configured to have an opening pressure that causes the reflux preventer to open when the coolant experiences a volume change that occurs below the boiling temperature of the coolant. The low opening pressure enables the coolant to already pass through the reflux preventer when a volume change of the coolant occurs below the boiling temperature of the coolant.

[0012] It is also possible that the first reflux preventer and / or the second reflux preventer is configured to remain open in the case of a volume change of the coolant below the boiling temperature, preferably a slight fluid flow.

[0013] In another embodiment, the first reflux preventer and / or the second reflux preventer is oriented in an ascending, preferably vertical or approximately vertical, mounting position. This can have the advantage that a reflux preventer in the form of, for example, a spherical check valve or a flap check valve is held in the closed position only by gravity. Therefore, the reflux preventer can have a relatively low opening pressure. The low opening pressure enables the reflux preventer to open already when a volume change of the coolant occurs, where the volume change occurs below the boiling temperature of the coolant.

[0014] In one embodiment, the first reflux preventer and / or the second reflux preventer is held in the closed position only by or substantially only by the gravity of the closing element (such as a closing ball or a closing flap) of the reflux preventer. Therefore, in the case of a relatively small mass of the closing element, a relatively low opening pressure can be achieved for the reflux preventer. This enables the reflux preventer to open already when a volume change of the coolant occurs, where the volume change occurs below the boiling temperature of the coolant.

[0015] In another embodiment, the first reflux preventer and / or the second reflux preventer is non-spring-loaded. By removing the spring prestress of the closure element of the reflux preventer, a relatively low opening pressure of the reflux preventer can also be achieved. This low opening pressure in turn causes the reflux preventer to open already when there is a volume change in the coolant, where the volume change occurs below the boiling temperature of the coolant.

[0016] In an implementation variant, the first reflux preventer and / or the second reflux preventer is a ball check valve. Preferably, the ball check valve can be oriented in an ascending, preferably vertical or approximately vertical, installation position, is non-spring-loaded and / or is held in the closed position only by or substantially only by the gravity of the closure ball of the ball check valve.

[0017] In another implementation variant, the first reflux preventer and / or the second reflux preventer is a flap check valve. Preferably, the flap check valve can be oriented in a horizontal or approximately horizontal installation position, is non-spring-loaded and / or is held in the closed position only by or substantially only by the gravity of the check flap of the flap check valve.

[0018] In one embodiment, the section of the coolant circuit preferably directly downstream of the cooling region can be oriented ascendingly, approximately vertically or vertically, preferably to form a steam bubble pump (air lift pump).

[0019] Suitably, the cooling region can be constructed and / or arranged for cooling the exhaust gas aftertreatment device.

[0020] Preferably, the coolant circuit can have a coolant pump (such as an internal combustion engine coolant pump). Thus, the coolant pump can be used to convey coolant during normal operation. Then, after the coolant pump is shut off, the circulation of the coolant can be achieved by the device disclosed herein by means of natural circulation.

[0021] It is possible that the coolant circuit is an internal combustion engine coolant circuit or at least a part thereof. The coolant can be an internal combustion engine coolant (such as engine cooling water). Alternatively, for example, additives can also be used as the coolant.

[0022] The invention also relates to a motor vehicle, preferably a commercial vehicle (such as a truck or a bus). The motor vehicle has an exhaust gas aftertreatment device (such as an SCR exhaust gas aftertreatment device), preferably an additive metering device (such as a reductant metering device). The motor vehicle also has a device for cooling the exhaust gas aftertreatment device as disclosed herein. It is also possible to use the device disclosed herein for passenger cars, large engines, all-terrain vehicles, stationary engines, marine engines, etc.

[0023] The present invention also relates to a method for cooling an exhaust gas aftertreatment device (such as an SCR exhaust gas aftertreatment device), preferably an additive metering device (such as a reducing agent metering device (such as a reducing agent injector)). The method includes cooling the exhaust gas aftertreatment device through a cooling zone of a coolant circuit, suitably by transferring heat from the exhaust gas aftertreatment device to the coolant in the cooling zone. The method also includes transporting the coolant through the coolant circuit in a natural circulation, which is caused by a volume change (such as without a phase change) of the coolant below the boiling temperature of the coolant in the cooling zone, preferably after the coolant pump in the coolant circuit is turned off. The same advantages as the device for cooling an exhaust gas aftertreatment device disclosed herein can be achieved by using this method.

[0024] In one embodiment, the transportation is continuous or quasi - continuous.

[0025] In another embodiment, the natural circulation is additionally caused by a volume change of the coolant in a coolant circuit section preferably directly upstream of the cooling zone and / or in a coolant circuit section preferably directly downstream of the cooling zone. Preferably, the coolant circuit section upstream of the cooling zone is defined by a reflux preventer. The coolant circuit section downstream of the cooling zone can also be defined by a reflux preventer.

[0026] In one implementation, the volume change of the coolant is a periodic volume change, preferably with alternating volume increase and volume decrease. The volume increase is preferably caused by heat feed from the exhaust gas aftertreatment device in the cooling zone, and the volume decrease is preferably caused by heat dissipation to the environment in the coolant circuit section downstream of the cooling zone.

[0027] In another implementation, cooling and the associated volume decrease of the coolant in the coolant circuit section downstream of the cooling zone cause the coolant to flow back to the cooling zone again.

[0028] In one implementation variant, the method uses the device for cooling an exhaust gas aftertreatment device as disclosed herein.

[0029] The devices and methods disclosed herein may also offer advantages over other possible solutions, but may also be combined with them. For example, if desired, the additional electric coolant pump in the coolant circuit may be omitted. The additional electric coolant pump may, for example, circulate the coolant in the cooling circuit even during the continuation flow time after the internal combustion engine and the internal combustion engine coolant pump are turned off. By this possible omission, for example, the cost of the additional coolant pump and the energy for driving the additional coolant pump may be saved. If desired, the steadily increasing pipe laying may also be omitted. In the case of the steadily increasing pipe laying leading from the exhaust gas aftertreatment device to the coolant compensating container or the engine block, a thermosiphon effect is generated due to the significantly higher temperature in the exhaust gas aftertreatment device. Here, the density change caused by the heating and evaporation of the coolant causes the coolant to recirculate. However, due to the spatial proportions and installation conditions when necessary, this cost - advantageous variant may be difficult or rarely achievable. If desired, the coolant reservoir above and near the exhaust gas aftertreatment device may also be omitted. When the coolant boils, the coolant reservoir can ensure faster condensation of the steam bubbles and the continued flow of the coolant. However, due to the circulation of the coolant in the remaining coolant circuit (in a hot stationary internal combustion engine when necessary), the flow direction at the exhaust gas aftertreatment device cannot be foreseen, so it is possible that the continued flow is not always ensured. In addition, this function may strongly depend on the installation position and the vehicle inclination.

[0030] The above - mentioned preferred embodiments and features of the present invention can be combined with each other arbitrarily. Other details and advantages of the present invention will be described below with reference to the drawings. Description of the Drawings

[0031] Figure 1 A schematic diagram showing an exemplary device for cooling an exhaust gas aftertreatment device according to the present disclosure; and

[0032] Figure 2 A schematic diagram showing the thermodynamic relationships that can be used by the method and device for cooling an exhaust gas aftertreatment device according to the present disclosure.

[0033] The embodiments shown in the drawings are at least partially consistent, so that similar or identical parts are provided with the same reference numerals, and their explanations can also refer to the descriptions of other embodiments or drawings to avoid repetition. Detailed Embodiments

[0034] Figure 1An exemplary device 10 for cooling an exhaust gas aftertreatment device 12 is shown. The exhaust gas aftertreatment device 12 can suitably be a metering device, such as an injector, for delivering a reducing agent into the exhaust gas line 14 of an internal combustion engine. The device 10, the exhaust gas aftertreatment device 12 and the exhaust gas line 14 can be included in an internal combustion engine (such as a diesel internal combustion engine). The internal combustion engine can suitably be included in a motor vehicle for driving the motor vehicle, which is preferably a commercial vehicle (such as a truck or a bus).

[0035] For example, an (e.g., aqueous) urea solution can be injected into the exhaust gas stream flowing in the exhaust gas line 14 by means of a metering device. The metering device can be part of an SCR catalytic converter device which additionally has an SCR catalytic converter in the exhaust gas line 14 downstream of the metering device. By means of the SCR catalytic converter device, nitrogen oxides in the exhaust gas stream can suitably be reduced. The metering device can be operated, for example, by an electronic control unit.

[0036] The device 10 includes a coolant circuit 16 having a cooling region 18. The coolant circuit 16 can be connected, for example, to the coolant circuit for cooling the internal combustion engine. The coolant circuit 16 can have a coolant pump (not shown), such as the coolant pump of the internal combustion engine. During operation of the internal combustion engine, the coolant pump can be operated. By operating the coolant pump, coolant (such as cooling water) is pumped through the coolant circuit 16. The exhaust gas aftertreatment device 12 is cooled by the cooling region 18 through which the coolant flows. The cooling region 18 can be configured, for example, as a cooling coil or a heat exchanger.

[0037] After the coolant pump is switched off, for example by switching off the internal combustion engine, the coolant is no longer actively pumped through the coolant circuit 16. Nevertheless, it can happen that the still hot components (such as pipes, etc.) of the exhaust gas line 14 continue to heat the exhaust gas aftertreatment device 12 (see Figure 1 : ). This can lead to damage to the components of the exhaust gas aftertreatment device 12 and a shortened service life. It will be explained below that the device 10 has one or more reflux preventers in order to be able to cool the exhaust gas aftertreatment device 12 in the event of the coolant pump being switched off.

[0038] The device 10 has a first check valve 20 as a first reflux preventer and a second check valve 22 as a second reflux preventer. The first check valve 20 is arranged upstream of the cooling zone 18. Thus, the first check valve 20 is arranged in the forward flow towards the cooling zone 18. The pipe section between the first check valve 20 and the cooling zone 18 is also referred to herein as the first section 24 of the coolant circuit 16. The second check valve 22 is arranged downstream of the cooling zone 18. Thus, the second check valve 22 is arranged in the return flow relative to the cooling zone 18. The pipe section between the cooling zone 18 and the second check valve 22 is also referred to herein as the second section 26 of the coolant circuit 16.

[0039] The check valves 20, 22 are constructed and designed such that they open already at a very low opening pressure. The check valves 20, 22 (or generally at least one reflux preventer) preferably open already at an opening pressure of less than or equal to 10 mbar, preferably less than or equal to 1 mbar, particularly preferably less than or equal to 0.1 mbar or 0.05 mbar. The opening pressure must suitably be low enough so that the reflux preventer remains open also at the minimum flow rate.

[0040] The low opening pressure of the check valves 20, 22 can be achieved in Figure 1 the embodiment in such a way that the check valves 20, 22 are non-spring-loaded ball check valves in a vertically installed position. Thereby, the check valves 20, 22 are held in the closed position only by the gravity of the closing balls of the check valves 20, 22. Here, not the entire weight of the closing ball for closing, but only the following part, which is not compensated in the coolant due to the rising of the closing ball. The low gravity of the ball can be provided by a low-mass ball. For example, the ball can be made of a plastic material such as nylon. The ball check valve also has the advantage that they exhibit only a very low flow resistance after opening.

[0041] For example, for a vertically oriented ball check valve without spring loading, the opening pressure can be calculated as follows:

[0042] The position factor depends on the position. As an average value, a position factor of 9.81 m / s² can be given.

[0043] In other embodiments, the low opening pressure of the reflux preventer can be achieved by additional and / or alternative measures. In addition to the purely vertical orientation of the reflux preventer, all ascending orientations (ascending from the inlet of the check valve to the outlet) can also be considered for the reflux preventer. For example, it is also conceivable that the check valve is oriented in a horizontal mounting position and is spring-loaded with a very low pre-stress in the closed position. As another example of a reflux preventer, a flap check valve can be used, which is, for example, oriented in a horizontal mounting position and whose check flap is held in the closed position only by its own weight.

[0044] As explained below, since the check valves 20, 22 have a very low opening pressure, a natural circulation of the coolant is generated in the coolant circuit 16 after the coolant pump in the coolant circuit 16 is shut off. In particular, the very low opening pressure enables the coolant to undergo natural circulation already within a temperature range that is still below the coolant boiling temperature. To ensure a continuous or at least quasi-continuous flow through the cooling region 18 and thus ensure continuous heat dissipation, the periodically occurring volume changes between the check valves 20, 22 can be used. The volume changes are caused by the temperature changes experienced by the flowing coolant, or in a higher temperature range by boiling and subsequent condensation.

[0045] When flowing through the cooling region 18, the coolant is heated by the exhaust gas aftertreatment device 12. The coolant expands. The first check valve 20 in the forward flow prevents the coolant from flowing back. The coolant is pressed into a return pipe that is colder than the exhaust gas aftertreatment device 12 due to the volume increase, i.e., into section 26. The second check valve 22 opens and the coolant passes through the second check valve 22. The coolant is cooled again in section 26 (see Figure 1 : ). Once the heat output from section 26 to the environment is greater than the heat flow fed to the coolant in the cooling region 18, the volume decreases and the coolant is suctioned through the first check valve 20. The second check valve 22 prevents the coolant from being sucked out of the section of the coolant circuit 16 (cooling path section) downstream of the second check valve 22.

[0046] Natural circulation is generated both within a temperature range below the boiling temperature of the coolant in the cooling region 18 and within a temperature range above the boiling temperature of the coolant in the cooling region 18. The thermodynamic processes causing the natural circulation are similar here. Due to the heat input in the cooling region 18, the density of the coolant decreases. The volume of the coolant increases. The increase in the volume of the coolant caused by the heat feed in the cooling region 18 causes the coolant to be discharged through the second check valve 22. The decrease in the volume of the coolant in the second section 26 due to cooling causes the coolant to flow back into the first section 24 through the first check valve 20. Since the opening pressure of the check valve is very low, preferably approximately zero, the circulation of the coolant can be caused only by (periodic) volume changes.

[0047] The second section 26 has an important influence on ensuring that the transport / natural circulation of the coolant does not stop. The second section 26 serves as a cooling path for cooling the coolant, where the coolant is associated with a volume reduction. Thereby, the coolant is re-sucked through the first check valve 20. The second section 26 can be suitably designed according to the corresponding installation conditions. The influencing variables to be considered here can be the heat transfer from the exhaust gas line 14 to the exhaust gas aftertreatment device 12, the coolant temperature at the inlet of the cooling zone 18, the ambient temperature in the area of the second section 26, the cooling system pressure, and / or the coolant composition.

[0048] Generally, two cases can be distinguished. In the first case, the temperature of the exhaust gas aftertreatment device 12 (e.g., the temperature of its inner wall) is lower than the boiling point of the coolant. No vapor bubbles appear in the coolant. In the second case, the temperature of the exhaust gas aftertreatment device 12 (e.g., the temperature of its inner wall) is higher than the boiling point of the coolant. In the cooling zone 18, vapor bubbles appear in the coolant, and these vapor bubbles can be re-condensed in the downstream section 26.

[0049] In the first case, if no boiling occurs, the coolant can be transported only by the (periodic) volume change caused by the temperature increase in the cooling zone 18 and subsequent cooling in the section 26. To prevent this process from stopping, the volume reduction between the check valves during the contraction phase must be at least as large numerically as the volume increase in this area during the expansion phase. Here, with reference to Figure 2 The following example can be generally applied:

[0050] △V Exp ≤△V Kon

[0051] After deformation, it is obtained:

[0052] V KB *(T KB (t2)-T KB (t0))≤V AS *(T AS (t0)-T AS (t2)),

[0053] where

[0054] △V Exp = the volume increase of the liquid between the check valves during the expansion phase

[0055] △V Kon = the volume reduction of the liquid between the check valves during the contraction phase

[0056] V KB = the volume of the cooling zone 18

[0057] V AS = Volume of the cooling path 26

[0058] T KB = Average medium temperature in the cooling zone 18

[0059] T AS = Average medium temperature of the cooling path 26

[0060] t0 = Start of the expansion phase

[0061] t1 = Start of the contraction phase

[0062] t2 = End of the compression phase.

[0063] The average feed heat flow to be considered, if necessary, for the design of the check valves 20, 22, the cooling zone 18 and / or the sections 24 and 26 can be referred to Figure 2 Calculated as follows:

[0064] Where

[0065]

[0066]

[0067] c p = Specific isobaric heat capacity of the coolant [kJ / kgK]

[0068] The temperature generated in section 26 mainly depends on the ambient temperature in the area of section 26, the outer surface of the tube in section 26, the heat transfer coefficient in section 26, the flow rate of the coolant and the flow type of the coolant (laminar or turbulent).

[0069] In the second case, if the temperature in the cooling zone 18 is higher than the boiling point of the coolant, the continuous heat discharge in section 26 can be, for example, so large that a temperature lower than the boiling temperature of the coolant is generated in section 26. As described above, the heat transfer generated in section 26 can be affected. Section 26 can be suitably long so that the vapor bubbles are at least partially, preferably substantially completely, condensed up to the second check valve 22.

[0070] Once the coolant in the cooling region 18 becomes hot enough to form vapor bubbles, two effects can occur: If there is still only vapor in the cooling region 18, heat transfer can hardly occur any more. As a result, the heat flow discharged is significantly greater than the heat flow fed in, and the coolant can continue to flow through the first check valve 20. If the vapor bubbles condense again in the section 26, the volume of the coolant suddenly decreases, whereupon the coolant also flows through the first check valve 20 again. Due to these effects, permanent, periodic volume changes occur in the region between the two check valves 20, 22, which results in a continuous (passive) pumping and recirculation of the coolant.

[0071] The design of the reflux preventer is also decisive for a continuous or quasi - continuous coolant circulation. The circulation is only caused by the volume changes that the coolant undergoes during passage. In order to interrupt the coolant flow as little as possible, as already described, a reflux preventer with a very low opening pressure can be used. For example, a ball check valve or a flap check valve or other types of reflux preventers can be used as the reflux preventer.

[0072] This document has referred to Figure 1 an embodiment in which the reflux preventer is arranged both in the forward flow towards the cooling region 18 and in the return flow after the cooling region 18. However, it is also possible to use only one reflux preventer and still cause the conveyance of the coolant. For example, the reflux preventer (e.g., a check valve) can be arranged upstream of the cooling region 18. The section 26 downstream of the cooling region 18 can rise, be approximately vertical or vertically oriented. Thereby, the function of a steam bubble pump (air lift pump) can be achieved. The very low opening pressure of the reflux preventer upstream of the cooling region 18 enables the coolant to flow continuously.

[0073] It is also possible to supplement a coolant reservoir to the device for cooling the exhaust gas aftertreatment device. For example, the coolant reservoir can be connected to the section 24. In addition, a reflux preventer can be arranged downstream of the cooling region 18.

[0074] This disclosure also relates to a method for cooling an exhaust gas aftertreatment device. This method can use the device 10 disclosed herein to cool the exhaust gas aftertreatment assembly 12.

[0075] The method includes cooling the exhaust gas aftertreatment device 12 through the cooling region 18 of the coolant circuit 16, preferably after the coolant pump in the coolant circuit 16 is switched off. The method also includes suitably continuously or quasi - continuously conveying the coolant by natural circulation through the coolant circuit 16, which natural circulation is caused by preferably periodic volume changes (e.g., without phase change) that have occurred when the coolant in the cooling region 18, in the section 24, and / or in the section 26 is below the coolant boiling temperature.

[0076] Suitably, the volume change of the coolant can be a periodic volume change, having alternating volume increases in the cooling region due to heat feed from the exhaust gas aftertreatment device and volume decreases in section 26 due to heat discharge to the environment.

[0077] The method can also include redirecting the coolant to the cooling region 18 by cooling and the resultant volume decrease of the coolant in section 26.

[0078] The invention is not limited to the above preferred embodiments. Rather, numerous variations and modifications are possible, which also utilize the concept of the invention and thus fall within the scope of protection. All range disclosures herein should be understood to have all values falling within the corresponding ranges individually disclosed, for example also as the respective preferred narrower outer boundaries of the corresponding ranges.

[0079] List of reference numerals

[0080] 10 Device for cooling an exhaust gas aftertreatment device

[0081] 12 Exhaust gas aftertreatment device

[0082] 14 Exhaust gas line

[0083] 16 Coolant circuit

[0084] 18 Cooling region

[0085] 20 First check valve (first reflux preventer)

[0086] 22 Second check valve (second reflux preventer)

[0087] 24 First section

[0088] 26 Second section (cooling path)

Claims

1. Apparatus (10) for cooling an exhaust gas aftertreatment device (12), said apparatus having: A coolant circuit (16) for guiding coolant, said coolant circuit having: A cooling zone (18) for heat transfer with the exhaust gas aftertreatment device (12); A first reflux preventer (20) disposed upstream of the cooling zone (18); A second reflux preventer (22) disposed downstream of the cooling zone (18); And A cooling path section between the cooling zone (18) and the second reflux preventer (22), Wherein the second reflux preventer (22) is constructed and / or designed such that at least one reflux preventer opens upon a change in the volume of coolant in the cooling zone (18), wherein the volume change occurs below the boiling temperature of the coolant, and wherein, The first reflux preventer (20) and / or the second reflux preventer (22) is constructed to have an opening pressure for opening the reflux preventer (20, 22) that is less than or equal to 10 mbar, and / or, The first reflux preventer (20) and / or the second reflux preventer (22) is constructed to have an opening pressure that causes the reflux preventer (20, 22) to open when the coolant undergoes a volume change that occurs below the boiling temperature of the coolant.

2. The apparatus (10) according to claim 1, wherein: The first reflux preventer (20) and / or the second reflux preventer (22) is constructed to remain open in the case of fluid flow caused by a volume change of coolant below the boiling temperature.

3. The apparatus (10) according to claim 1 or claim 2, wherein: The first reflux preventer (20) and / or the second reflux preventer (22) is oriented in an upwardly installed position.

4. The apparatus (10) according to claim 1 or claim 2, wherein: The first reflux preventer (20) and / or the second reflux preventer (22) is held in the closed position only by the gravity of the closing element of the reflux preventer (20, 22).

5. The apparatus (10) according to claim 1 or claim 2, wherein: The first reflux preventer (20) and / or the second reflux preventer (22) is non-spring-loaded.

6. The apparatus (10) according to claim 1 or claim 2, wherein: The first reflux preventer (20) and / or the second reflux preventer (22) is a ball check valve.

7. The apparatus (10) according to claim 1 or claim 2, wherein: The first reflux preventer (20) and / or the second reflux preventer (22) is a flap check valve.

8. The device (10) according to claim 1 or claim 2, wherein: The section of the coolant circuit (16) downstream of the cooling zone (18) is oriented vertically upward.

9. The apparatus (10) according to claim 1, wherein: The exhaust gas aftertreatment device (12) is an additive metering device.

10. The apparatus (10) according to claim 1, wherein: The reflux preventer is a check valve.

11. The device (10) according to claim 1, wherein: the at least one reflux preventer is constructed and / or designed such that it opens when there is a change in the coolant volume in the cooling region (18) and / or in a cooling path section of the coolant circuit (16).

12. The device (10) according to claim 1, wherein: the volume change occurs below the boiling temperature of the coolant to provide a continuous or quasi - continuous natural circulation of the coolant in the coolant circuit (16) below the boiling temperature of the coolant.

13. The device (10) according to claim 1, wherein: the first reflux preventer (20) is a check valve.

14. The device (10) according to claim 1, wherein: the second reflux preventer (22) is a check valve.

15. The device (10) according to claim 1, wherein: the second reflux preventer is spaced from the cooling region (18).

16. The device (10) according to claim 2, wherein: the first reflux preventer (20) and / or the second reflux preventer (22) is constructed to have an opening pressure for opening the reflux preventer (20, 22) that is less than or equal to 1 mbar.

17. The device (10) according to claim 2, wherein: the first reflux preventer (20) and / or the second reflux preventer (22) is constructed to have an opening pressure for opening the reflux preventer (20, 22) that is less than or equal to 0.1 mbar or 0.05 mbar.

18. The device (10) according to claim 2, wherein: the first reflux preventer (20) and / or the second reflux preventer (22) is constructed to remain open in the case of a slight fluid flow caused by a volume change of the coolant below the boiling temperature.

19. The device (10) according to claim 3, wherein: the first reflux preventer (20) and / or the second reflux preventer (22) is oriented in an upward, vertical mounting position.

20. The device (10) according to claim 6, wherein: the ball check valve: is oriented in an upward mounting position, and / or is non - spring - loaded; and / or is held in the closed position only by the gravity of the closing ball of the ball check valve.

21. The device (10) according to claim 20, wherein: the ball check valve is oriented in an upward, vertical mounting position.

22. The device (10) according to claim 7, wherein: the flap check valve: is oriented in a horizontal mounting position; and / or is non - spring - loaded; and / or is held in the closed position only by the gravity of the check flap of the flap check valve.

23. The device (10) according to claim 8, wherein: the section of the coolant circuit (16) directly downstream of the cooling region (18) is oriented vertically upward.

24. The device (10) according to claim 8, wherein: The section of the coolant circuit (16) downstream of the cooling region (18) is oriented vertically and rising to form a vapor bubble pump.

25. The device (10) according to claim 24, wherein: The vapor bubble pump is an air lift pump.

26. A motor vehicle, comprising: An exhaust gas aftertreatment device (12), and The device (10) according to any one of the preceding claims.

27. The motor vehicle according to claim 26, wherein: The motor vehicle is a commercial vehicle.

28. A method for cooling an exhaust gas aftertreatment device (12), the method using the device (10) according to any one of claims 1 to 25, the method comprising: Cooling the exhaust gas aftertreatment device (12) through the cooling region (18) of the coolant circuit (16); And Transporting the coolant through the coolant circuit (16) by natural circulation, the natural circulation being caused by a change in volume of the coolant that occurs below the boiling temperature of the coolant in the cooling region (18).

29. The method according to claim 28, wherein: The transportation is continuous or quasi - continuous.

30. The method according to claim 28 or claim 29, wherein: The natural circulation is additionally caused by a change in volume of the coolant in the section of the coolant circuit (16) upstream of the cooling region (18) and / or in the section of the coolant circuit (16) downstream of the cooling region (18).

31. The method according to claim 28 or claim 29, wherein: The change in volume of the coolant is a periodic change in volume; and / or The coolant is caused to flow back to the cooling region (18) by cooling and the associated decrease in volume of the coolant in the section of the coolant circuit (16) downstream of the cooling region (18).

32. The method according to claim 28, wherein: The exhaust gas aftertreatment device (12) is an additive metering device.

33. The method according to claim 28, wherein: After the coolant pump in the coolant circuit (16) is switched off, the natural circulation is caused by a change in volume of the coolant that occurs below the boiling temperature of the coolant in the cooling region (18).

34. The method according to claim 30, wherein: The natural circulation is additionally caused by a change in volume of the coolant in the section of the coolant circuit (16) directly upstream of the cooling region (18) and / or in the section of the coolant circuit (16) directly downstream of the cooling region (18).

35. The method according to claim 30, wherein: The section of the coolant circuit (16) upstream of the cooling region (18) is defined by the first reflux preventer (20); and / or The section of the coolant circuit (16) downstream of the cooling region (18) is defined by the second reflux preventer (22).

36. The method according to claim 31, wherein: The periodic change in volume has alternating volume increases and volume decreases.

37. The method according to claim 36, wherein: The volume increase is caused in the cooling region (18) by the heat feed from the exhaust gas aftertreatment device (12).

38. The method according to claim 36, wherein: The volume decrease is caused in the section of the coolant circuit (16) downstream of the cooling region (18) by heat dissipation to the environment.

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