DE102021204807A1 - Sensor arrangement, exhaust aftertreatment device, internal combustion engine, vehicle and method for operating an exhaust aftertreatment device - Google Patents

Abstract

The invention relates to a sensor arrangement (29) for determining at least one exhaust gas parameter in an exhaust gas flow, with a housing (31) which has an exhaust gas guide section (33) and a sensor chamber (35) in which at least one exhaust gas sensor (15) is arranged is, wherein- the housing (31) is set up to be arranged on an exhaust pipe section (7) of an exhaust line (8) for determining the at least one exhaust gas parameter in the exhaust pipe section (7), wherein- the sensor arrangement (29) has a Has a shielding device (25) that can be moved either into a shielding position and a release position, wherein the shielding device (25) is set up to release a fluidic connection between the exhaust gas routing section (33) and the sensor chamber (35) in the release position in such a way that during operation of the sensor arrangement (29), exhaust gas from the exhaust gas guide section (33) into the sensor chamber (35) to the at least one exhaust gas sensor (15). and wherein the shielding device (25) is set up to shield the sensor chamber (35) from the exhaust gas guide section (33) in the shielding position in such a way that during operation of the sensor arrangement (29) no exhaust gas reaches the at least one exhaust gas sensor ( 15) can reach.

Description

The invention relates to a sensor arrangement, an exhaust gas aftertreatment device, an internal combustion engine, a vehicle with such an internal combustion engine, and a method for operating an exhaust gas aftertreatment device.

When operating sensor assemblies that are set up to determine at least one exhaust gas parameter in an exhaust gas flow, in particular an internal combustion engine, there is at least some applications with the problem that the sensor assemblies at certain times and in particular depending on a specific configuration of the exhaust gas flow are needed, where they are not only not needed at other times and especially when the exhaust gas flow is configured differently, but are even adversely affected by the exhaust gas flow. For example, when operating an internal combustion engine in a vehicle, in particular a ship, the fact may arise that this vehicle is temporarily operated in emission-regulated areas where a specific exhaust gas aftertreatment is desired or even prescribed. The sensor arrangement is then required to ensure exhaust gas aftertreatment. In other, non-emission-regulated areas, on the other hand, exhaust gas after-treatment is to be omitted and the internal combustion engine may even be operated with a different fuel, for example marine heavy oil. The exhaust gas flow emitted by the internal combustion engine can then include components, in particular sulfur or sulfur compounds, which impair, in particular contaminate, the sensor arrangement. There is therefore a fundamental need to be able to use the sensor arrangement selectively and to be able to selectively spare it from being adversely affected by the exhaust gas.

The invention is therefore based on the object of creating a sensor arrangement, an exhaust gas aftertreatment device, an internal combustion engine, a vehicle and a method for operating an exhaust gas aftertreatment device, with the disadvantages mentioned being at least partially alleviated, preferably avoided, with particularly preferred advantages over the ones described design can be realized.

The object is achieved by providing the present technical teaching, in particular the teaching of the independent claims and the embodiments disclosed in the dependent claims and the description.

The object is achieved in particular by creating a sensor arrangement for determining at least one exhaust gas parameter in an exhaust gas flow, which has a housing which has an exhaust gas guide section and a sensor chamber. At least one exhaust gas sensor is arranged in the sensor chamber. The housing is set up to be arranged on an exhaust pipe section of an exhaust line in order to be able to determine the at least one exhaust gas parameter in the exhaust pipe section. The sensor arrangement has a shielding device that can be selectively shifted into a shielding position and into a release position. The shielding device is set up to release a fluidic connection between the exhaust gas routing section of the housing and the sensor chamber in the release position in such a way that during operation of the sensor arrangement, exhaust gas can flow from the exhaust gas routing section into the sensor chamber and thus to the at least one exhaust gas sensor. The shielding device is also set up to shield the sensor chamber from the exhaust gas routing section in the shielding position in such a way that no exhaust gas can reach the at least one exhaust gas sensor during operation of the sensor arrangement. It is thus advantageously possible, in particular, to operate the sensor arrangement in two different operating states, wherein in one operating state, which corresponds to the release position of the shielding device, the at least one exhaust gas parameter can be detected in the exhaust gas flow passing through the exhaust pipe section, which in particular allows for regulated operation an exhaust gas aftertreatment device, whereby, on the other hand, in a second operating state, which corresponds to the shielding position of the shielding device, the exhaust gas sensor is effectively shielded from the exhaust gas flow, so that it is not adversely affected by the exhaust gas, in particular by the harmful substances contained in the exhaust gas flow, for example sulfur or sulfur compounds can. In this way, in particular, a purposeful operation that extends the service life of the sensor arrangement in different environments, in particular in areas with different or non-existent emission regulations, is made possible for the sensor arrangement.

An exhaust gas parameter is understood here to mean a physical and/or chemical variable that can be measured in the exhaust gas flow, in particular a pollutant concentration, a concentration of another substance, for example oxygen, a pressure and/or a temperature. Accordingly, the exhaust gas sensor is preferably set up to measure such an exhaust gas parameter. The exhaust gas sensor is very particularly preferably set up to detect a nitrogen oxide concentration in the exhaust gas, be it nitrogen monoxide, nitrogen dioxide, or a total nitrogen oxide concentration, or a reducing agent concentration, in particular an ammonia concentration. The sensor arrangement is preferably set up to determine the at least one exhaust gas parameter in an exhaust gas flow of an internal combustion engine. In particular, the sensor arrangement is set up for arrangement and use in the exhaust system of an internal combustion engine.

The housing can preferably be arranged on the exhaust pipe section in such a way that at least the exhaust gas guide section protrudes into the exhaust pipe section and in particular into an exhaust gas flow guided in the exhaust pipe section.

The exhaust gas routing section is preferably a part of the housing which is set up to conduct exhaust gas from an exhaust gas flow passing through the exhaust pipe section--preferably a proportion of the exhaust gas flow representative of an exhaust gas composition in the exhaust pipe section--into the sensor chamber. Preferably, the exhaust gas routing section is further set up to cause a local calming of the flow and thus enable a meaningful and representative measurement of the at least one exhaust gas parameter. In a preferred embodiment, the exhaust gas routing section is designed as a sampling pipe that is at least partially open on the inflow side, which can be arranged with a pipe longitudinal axis preferably perpendicular to the exhaust gas flow in the exhaust pipe section. The inflow side is that transverse side of the sampling tube which faces the inflowing exhaust gas. The sampling tube preferably has a plurality of inflow openings, in particular bores, on the inflow side, through which exhaust gas can enter the sampling tube and thus the exhaust gas routing section. The sensor chamber is preferably arranged at one end of the sampling tube, in particular at a front end of the sampling tube.

It is possible for exactly one exhaust gas sensor to be arranged in the sensor chamber. However, it is also possible for a plurality of exhaust gas sensors to be arranged in the sensor chamber, preferably exactly two exhaust gas sensors being arranged.

The exhaust gas line section is in particular a part of an exhaust line section, preferably a pipe, pipe section or also a plurality of tubes, it being possible for an exhaust gas flow of the exhaust gas line to be guided along the exhaust line section.

According to a development of the invention, it is provided that the shielding device has a valve device which is arranged and set up to release the fluidic connection between the exhaust gas routing section and the sensor chamber in the release position and to block it in the shielding position. In this way, the valve device can be used to ensure in a simple and at the same time very effective manner that the exhaust gas sensor is acted upon by exhaust gas in the release position and is shielded from exhaust gas in the shielding position. The valve device is preferably arranged on the housing or in the housing, in particular between the exhaust gas routing section and the sensor chamber. The valve device preferably has a switching valve, in particular an electrically or electronically controllable switching valve.

According to a development of the invention, it is provided that the shielding device has a scavenging air device, the scavenging air device having a scavenging air source. The scavenging air source can be fluidically connected to the housing, in particular to the sensor chamber. The scavenging air device is set up to fluidically connect the scavenging air source to the sensor chamber in the shielding position, so that scavenging air flows through the sensor chamber in the direction of the exhaust gas routing section. The scavenging air device is also set up to fluidically separate the scavenging air source from the sensor chamber in the release position. In this way, exhaust gas can be applied to the at least one exhaust gas sensor very efficiently on the one hand in the release position and on the other hand it can be spared from exhaust gas in the shielding position, in particular in that no scavenging air flows through the sensor chamber in the release position, with a scavenging air flow from the sensor chamber in the direction of the Exhaust gas guide section is provided in such a way that the exhaust gas sensor is quasi blown free of exhaust gas, with no exhaust gas being able to get into the sensor chamber from the direction of the exhaust gas guide section due to the scavenging air flow. The scavenging air flow also preferably prevents exhaust gas from entering the exhaust gas line section into the exhaust gas routing section.

In a preferred embodiment, the scavenging air source can be a charge air line of an internal combustion engine, with a corresponding scavenging air pressure preferably being provided by a compressor, for example a compressor or the compressor of an exhaust gas turbocharger. However, the scavenging air source can also be a scavenging air reservoir, in which the charge air of the internal combustion engine can be stored at certain operating points, in particular with an increase in pressure, for example by a compressor, in particular a compressor or a compressor of an exhaust gas turbocharger internal combustion engine. However, it is also possible for the scavenging air source to be a suitably designed air pump which, for example, conveys ambient air into the sensor chamber. The scavenging air pressure is preferably chosen to be higher than an exhaust gas back pressure, so that the at least one exhaust gas sensor is always surrounded by scavenging air when the scavenging air device is active. The scavenging air is preferably disposed of via the exhaust gas flow.

In a preferred embodiment, the scavenging air device has at least one scavenging air nozzle, which is arranged in the sensor chamber or on the sensor chamber and is aligned in such a way that a scavenging air flow can be generated from the at least one nozzle in the direction of the exhaust gas routing section through the sensor chamber. The at least one nozzle is advantageously aligned in the direction of the exhaust gas routing section.

According to a development of the invention, it is provided that the at least one exhaust gas sensor is selected from a group consisting of: a nitrogen oxide sensor and an ammonia sensor. In particular, these sensors are required on the one hand for exhaust gas aftertreatment, particularly in an emissions-regulated area, in particular for selective catalytic reduction of nitrogen oxides, preferably while avoiding ammonia slip from the exhaust gas aftertreatment device. In addition, these sensors are particularly susceptible to contamination, particularly from exhaust gases containing sulfur.

In a preferred embodiment, it is possible for both at least one nitrogen oxide sensor and at least one ammonia sensor, in particular precisely one nitrogen oxide sensor and precisely one ammonia sensor, to be arranged in the sensor chamber.

The object is also achieved by creating an exhaust gas aftertreatment device for aftertreatment of an exhaust gas flow, in particular for catalytic aftertreatment of an exhaust gas flow, preferably for selective catalytic reduction of nitrogen oxides in the exhaust gas flow. The exhaust gas aftertreatment device has an exhaust pipe section, which has an aftertreatment section and a sensor section arranged downstream of the aftertreatment section. The aftertreatment section has at least one exhaust aftertreatment element. The sensor section has at least one exhaust gas sensor. The exhaust gas after-treatment device also has a bypass path, which opens out of the exhaust pipe section upstream of the after-treatment section and into the exhaust pipe section again between the after-treatment section and the sensor section. In particular, an exhaust gas flow that at least partially flows through the exhaust pipe section can therefore flow through the bypass path or through the aftertreatment section. Regardless of whether the exhaust flow flows through the bypass path or through the aftertreatment section, it always passes through the sensor section.

The exhaust gas aftertreatment device has an actuating device that is set up to selectively guide the exhaust gas flow through the aftertreatment section into the sensor section in a first functional position and at the same time to block the bypass path, and to guide the exhaust gas flow through the bypass path into the sensor section in a second functional position and at the same time to lock the post-processing section. The exhaust gas flow is thus either guided only through the aftertreatment section and not through the bypass path, or only through the bypass path and not through the aftertreatment section.

The exhaust gas aftertreatment device also has a shielding device that is set up to selectively allow exhaust gas to flow against the at least one exhaust gas sensor or to shield the at least one exhaust gas sensor from exhaust gas. The exhaust gas sensor can therefore either be exposed to exhaust gas or spared from exhaust gas.

Finally, the exhaust gas aftertreatment device has a control device that is operatively connected to the actuating device and to the shielding device. The control device is also set up to switch the actuating device either to the first functional position or to the second functional position, and to activate the shielding device in such a way that in the first functional position of the actuating device, exhaust gas is permitted to flow against the at least one exhaust gas sensor, wherein in the second functional position of the actuating device, the at least one exhaust gas sensor is shielded from exhaust gas. When exhaust gas flows through the after-treatment section and the at least one exhaust-gas after-treatment element is used, the exhaust-gas sensor is subjected to exhaust gas, so that regulated operation of the exhaust-gas after-treatment element is possible. If, on the other hand, the exhaust gas flow is guided along the bypass path, the exhaust gas sensor is shielded from exhaust gas, so that it is particularly advantageously not exposed to any contamination. In this respect, in connection with the exhaust aftertreatment device, in particular the pros parts that have already been described in connection with the sensor arrangement.

According to a development of the invention, it is provided that the exhaust gas aftertreatment device has a sensor arrangement according to the invention or a sensor arrangement according to one of the exemplary embodiments described above. In particular, the at least one exhaust gas sensor of the sensor arrangement is the previously mentioned exhaust gas sensor of the exhaust gas aftertreatment device. Furthermore, in particular the shielding device of the sensor arrangement is the previously mentioned shielding device of the exhaust gas aftertreatment device. Thus, in particular, the sensor arrangement provides both the at least one exhaust gas sensor and the shielding device for the exhaust gas aftertreatment device. The control device is operatively connected to the sensor arrangement and set up to switch the shielding device of the sensor arrangement to the release position when the actuating device is in the first functional position, and to switch the shielding device of the sensor arrangement to the shielding position when the actuating device is in the second functional position . In this way, the advantages already mentioned above are realized particularly effectively.

The object is also achieved by creating an internal combustion engine which has at least one sensor arrangement according to the invention or a sensor arrangement according to one of the exemplary embodiments described above. Alternatively or additionally, the internal combustion engine has an exhaust gas aftertreatment device according to the invention or an exhaust gas aftertreatment device according to one of the exemplary embodiments described above. In connection with the internal combustion engine, the advantages that have already been explained in connection with the sensor arrangement and the exhaust gas aftertreatment device are realized in particular.

The internal combustion engine is preferably set up to be operated in a vehicle, in particular to drive the vehicle. The internal combustion engine is preferably set up to drive a ship vehicle.

The internal combustion engine is preferably designed as a reciprocating piston engine, in particular as a large engine.

The object is also achieved by creating a vehicle, in particular a ship, which has an internal combustion engine according to the invention or an internal combustion engine according to one of the exemplary embodiments described above. In connection with the vehicle, the advantages already mentioned above in connection with the sensor arrangement, the exhaust gas aftertreatment device and the internal combustion engine are realized in particular. In particular, such a vehicle, especially a ship, can move both in emission-regulated areas and in areas without emission regulation, with the operation of the internal combustion engine being able to be matched to the respectively prevailing or possibly completely non-existent regulations. In particular, in an emissions-regulated area, a fuel can be used to operate the internal combustion engine that burns comparatively cleanly, with exhaust gas aftertreatment, in particular selective catalytic reduction of nitrogen oxides, also being able to be carried out. In this case, the at least one exhaust gas sensor of the sensor arrangement is advantageously also used in order to regulate the operation of the exhaust gas aftertreatment device. On the other hand, the internal combustion engine can be operated in non-emission-regulated areas with a cheaper fuel that burns less cleanly, with no exhaust gas aftertreatment, in particular no selective catalytic reduction of nitrogen oxides, being carried out. In this case, the at least one exhaust gas sensor is advantageously shielded from the exhaust gas that is harmful to it.

Finally, the object is also achieved by creating a method for operating an exhaust gas aftertreatment device, wherein the exhaust gas aftertreatment device is operated in an aftertreatment position or in a rest position depending on at least one operating parameter. In the aftertreatment position, an exhaust gas flow is directed through at least one exhaust gas aftertreatment element, and the exhaust gas flow is applied to at least one exhaust gas sensor downstream of the at least one exhaust gas aftertreatment element. The operation of the at least one exhaust gas aftertreatment element is preferably regulated by means of the at least one exhaust gas sensor. In the rest position, the exhaust gas flow is routed past the at least one exhaust gas aftertreatment element, and the at least one exhaust gas sensor is shielded from the exhaust gas flow. In connection with the method, there are in particular the advantages already explained in connection with the sensor arrangement, the exhaust gas aftertreatment device, the internal combustion engine and the vehicle.

As part of the method, an exhaust gas aftertreatment device according to the invention or an exhaust gas aftertreatment device according to one of the embodiments described above is preferred tion examples operated. The rest position of the exhaust gas after-treatment device preferably corresponds to the second functional position of the actuating device, with the after-treatment position corresponding to the first functional position of the actuating device. Correspondingly, the shielding position of the shielding device is preferably assigned to the rest position, and the release position of the shielding device is assigned to the post-treatment position.

The at least one exhaust gas sensor is in particular the at least one exhaust gas sensor of a sensor arrangement according to the invention or a sensor arrangement according to one of the exemplary embodiments described above.

According to one development of the invention, it is provided that a geographic location at which the method is carried out is used as the at least one operating parameter. In this way in particular, the operation of the exhaust gas aftertreatment device can advantageously be adapted to specific conditions that depend on the geographic location at which the method is carried out, in particular on the emission regulations that prevail there or are absent.

• 1 eine schematische Darstellung eines Ausführungsbeispiels einer Brennkraftmaschine mit einem Ausführungsbeispiel einer Abgasnachbehandlungseinrichtung;
• 2 eine schematische Darstellung eines ersten Ausführungsbeispiels einer Sensor-Anordnung;
• 3 eine schematische Darstellung eines zweiten Ausführungsbeispiels einer Sensor-Anordnung, und
• 4 eine schematische Darstellung einer Ausführungsform eines Verfahrens zum Betreiben einer Abgasnachbehandlungseinrichtung.

The invention is explained in more detail below with reference to the drawing. show:

• 1 a schematic representation of an embodiment of an internal combustion engine with an embodiment of an exhaust gas aftertreatment device;
• 2 a schematic representation of a first exemplary embodiment of a sensor arrangement;
• 3 a schematic representation of a second exemplary embodiment of a sensor arrangement, and
• 4 a schematic representation of an embodiment of a method for operating an exhaust gas aftertreatment device.

1 shows a schematic representation of an exemplary embodiment of an internal combustion engine 1 with an exemplary embodiment of an exhaust gas aftertreatment device 3. At a) an overview of the internal combustion engine 1 with the exhaust gas aftertreatment device 3 is shown; at b) a detailed representation of a part of the exhaust gas aftertreatment device 3 is shown.

The internal combustion engine 1 is preferably used to drive a vehicle 2 or is otherwise part of the vehicle 2, in particular part of an energy supply for the vehicle 2. The vehicle 2 is preferably a ship, in particular a yacht, a ferry, a container ship or cargo ship, or a submarine .

The internal combustion engine 1 has an engine block 5 in which at least one fuel is reacted with combustion air, with exhaust gas being produced. This exhaust gas enters exhaust aftertreatment device 3.

The exhaust gas aftertreatment device 3 is set up for, in particular, catalytic aftertreatment of an exhaust gas flow, in particular for the selective catalytic reduction of nitrogen oxides contained in the exhaust gas flow. The exhaust gas aftertreatment device 3 has an exhaust pipe section 7 which in turn has an aftertreatment section 9 with at least one exhaust gas aftertreatment element 11 and a sensor section 13 with at least one exhaust gas sensor 15 arranged downstream of the aftertreatment section 9 . Two exhaust gas sensors 15, which are arranged in the sensor section 13, are shown schematically here. The exhaust gas aftertreatment element 11 is preferably set up for the selective catalytic oxidation of nitrogen oxides, in particular it is preferably provided that the exhaust gas aftertreatment element 11 is designed as an SCR catalytic converter.

The exhaust pipe section 7 is in particular part of an exhaust line 8 of the internal combustion engine 1.

Further exhaust gas sensors 17 are preferably also arranged upstream of the exhaust gas aftertreatment element 11 . In this respect, the regulation of the operation of the exhaust gas aftertreatment device 3 can be improved if at least one exhaust gas parameter is measured both upstream and downstream of the exhaust gas aftertreatment element 11 . In this respect, the exhaust gas sensors 15 and the further exhaust gas sensors 17 can in particular be the same exhaust gas sensors, that is to say exhaust gas sensors which are set up to detect the same exhaust gas parameters; however, it is also possible for the exhaust gas sensors 15 and the additional exhaust gas sensors 17 to detect different exhaust gas parameters. In particular, it is preferably provided that the two exhaust gas sensors 15 detect different exhaust gas parameters, in which case in particular one exhaust gas sensor 15 can be in the form of a nitrogen oxide sensor and the other exhaust gas sensor 15 can be in the form of an ammonia sensor. Correspondingly, the two further exhaust gas sensors 17 can also detect different exhaust gas parameters. It is also possible that one of the exhaust gas sensors 15 or the other exhaust gas sensors 17 is an exhaust gas temperature sensor.

The exhaust gas aftertreatment device 3 also has a bypass path 19, which here includes two partial bypass paths, namely a first partial bypass path 19.1 and a second partial bypass path 19.2. The partial bypass paths 19.1, 19.2 are preferably of identical design, so that reference is only made in general to a bypass path 19 in the following.

The bypass path 19 opens out of the exhaust pipe section 7 upstream of the after-treatment section 9 and opens out again into the exhaust pipe section 7 between the after-treatment section 9 and the sensor section 13 . The terms “upstream” and “downstream” refer to the flow direction of the exhaust gas, in particular starting from the engine block 5 in the direction of the exhaust gas sensors 15. The bypass path 19 serves to bypass the exhaust gas aftertreatment element 11; the exhaust gas flow is routed around the exhaust gas aftertreatment element 11 via the bypass path 19 .

The exhaust gas after-treatment device 3 also has an actuating device 21 which is set up, in a first functional position, to guide an exhaust gas flow through the after-treatment section 9 into the sensor section 13, thereby blocking the bypass path 19, in particular both partial bypass paths 19.1, 19.2, and in a second functional position, to guide the exhaust gas flow through the bypass path 19, in particular through both partial bypass paths 19.1, 19.2, into the sensor section 13 and at the same time to block the post-treatment section 9. For this purpose, the adjusting device 21 preferably has a plurality of controllable exhaust gas flaps 23 .

The exhaust gas aftertreatment device 3 also has a shielding device 25, shown only schematically, which is set up to optionally allow exhaust gas to flow against the at least one exhaust gas sensor 15 or to shield the at least one exhaust gas sensor 15 from exhaust gas.

The additional exhaust gas sensors 17 are preferably arranged behind the exhaust gas flaps 23, which are assigned to the exhaust gas aftertreatment element 11, and are therefore protected when the exhaust gas flow is guided along the bypass path 19.

Furthermore, the exhaust gas after-treatment device 3 has a control device 27, which is operatively connected to the actuating device 21 and to the shielding device 25 and is set up to switch the actuating device 21 selectively to the first functional position and to the second functional position, and to control the shielding device 25 in such a way that that in the first functional position of the actuating device 21 a flow of the at least one exhaust gas sensor 15 with exhaust gas is permitted, wherein in the second functional position of the actuating device 21 the exhaust gas sensors 15 are shielded from exhaust gas.

The control device 27 is preferably operatively connected to the exhaust gas sensors 15 for detecting the at least one exhaust gas parameter. In addition, it is preferably also functionally connected to the additional exhaust gas sensors 17 for detecting the at least one exhaust gas parameter or an additional exhaust gas parameter. In addition, the control device 27 is operatively connected to the actuating device 21 and to the shielding device 25 for their respective activation, in particular synchronized activation. In a preferred embodiment, the control device 27 is a control unit of the internal combustion engine 1 or is integrated into a control unit of the internal combustion engine 1, either as a hardware module or as a software module. In a preferred embodiment, the control device 27 is what is known as an engine control unit (ECU).

In b) a detailed view of the sensor section 13 of the exhaust pipe section 7 is shown in particular. It can be seen here that the exhaust gas sensors 15 are part of a sensor arrangement 29 which has a housing 31 which is arranged on the exhaust pipe section 7 in the sensor section 13 in order to measure the at least one exhaust gas parameter in the exhaust pipe section 7 .

The housing 31 has an exhaust gas routing section 33 and a sensor chamber 35 arranged here in particular above the exhaust gas routing section 33, with at least one exhaust gas sensor 15, here preferably two exhaust gas sensors 15, in particular the two exhaust gas sensors 15 of the exhaust gas aftertreatment device 3, being arranged in the sensor chamber 35. The sensor arrangement 29 also has the shielding device 25, which is likewise indicated here schematically and which can be shifted optionally into a shielding position and a release position. The shielding device 25 is set up to release a fluidic connection between the exhaust gas routing section 33 and the sensor chamber 35 in the release position in such a way that during operation of the sensor arrangement 29 exhaust gas can flow from the exhaust gas routing section 33 into the sensor chamber 35 to the at least one exhaust gas sensor 15 , And being in the shielding position, the sensor chamber 35 is shielded from the exhaust gas guide section 33 in such a way that the operation of the Sensor arrangement 29 no exhaust gas can reach the at least one exhaust gas sensor 15.

As already explained, one of the exhaust gas sensors 15 arranged in the sensor chamber 35 is preferably a nitrogen oxide sensor, the other exhaust gas sensor 15 arranged in the sensor chamber 35 being an ammonia sensor.

The control device 27 is in particular operatively connected to the sensor arrangement 29 and set up to switch the shielding device 25 of the sensor arrangement 29 to the release position when the actuating device 21 is in the first functional position and to the shielding position when the actuating device 21 is in the second functional position.

2 1 shows a schematic representation of a first exemplary embodiment of the sensor arrangement 29. Identical and functionally identical elements are provided with the same reference symbols in all figures, so that reference is made to the respective preceding description.

In 2 a) shows a partially sectioned first view and b) shows a second view of the sensor arrangement 29. It can be seen in particular that the exhaust gas guide section 33 is part of the housing 31, which is designed as a sampling tube that is open at least in certain areas on the inflow side, with inflow openings 37 being particularly visible here, of which only one is denoted by the corresponding reference number for the sake of clarity.

The shielding device 25 here has a valve device 39 which is arranged and set up to release the fluidic connection between the exhaust gas routing section 33 and the sensor chamber 35 in the release position and to block it in the shielding position. In particular, the valve device 39 has a displaceable valve element 41 for this purpose. The valve device 39 can in particular be actuated, preferably in the form of a controllable switching valve, the control device 27 being operatively connected to the valve device 39 in order to actuate it. A through-opening 43 between the exhaust-gas guide section 33 and the sensor chamber 35 can in particular be selectively blocked and unblocked by suitable displacement of the valve element 41 . In b) it is shown schematically by means of two crossed first arrows P1 that in the shielding position no exhaust gas entering the exhaust gas guide section 33 can get further into the sensor chamber 35 and thus to the exhaust gas sensors 15 .

3 shows a schematic representation of a second exemplary embodiment of the sensor arrangement 29 . In this exemplary embodiment, the shielding device 25 has a scavenging air device 45 . The scavenging air device 45 has a scavenging air source 47 that can be fluidically connected to the housing 31 and in particular to the sensor chamber 35, wherein the scavenging air device 45 is set up to fluidly connect the scavenging air source 47 to the sensor chamber 35 in the shielding position, so that the sensor chamber 35 is flowed through in the direction of the exhaust gas guide section 33 with scavenging air. The scavenging air device 45 is also set up to fluidically separate the scavenging air source 47 from the sensor chamber 35 in the release position.

In this respect, the scavenging air device 45 preferably has a switching valve 49 in a fluidic connection between the scavenging air source 47 and the sensor chamber 35, which is designed to be controllable and is operatively connected to the control device 27 for its control.

At a) and b) again different views of the second embodiment of the sensor arrangement 29 are shown. In b) two second arrows P2 are used to show that in the shielding position, scavenging air flows through the exhaust gas routing section 33 from the sensor chamber 35, so that preferably no exhaust gas enters the exhaust gas routing section 33, but in particular no exhaust gas from the exhaust gas routing section 33 into the Sensor chamber 35 can reach. The exhaust gas sensors 15 are thus freed from exhaust gas by the scavenging air flow, in particular blown free. The pressure of the scavenging air is preferably chosen to be higher than an exhaust gas back pressure in the sensor section 13, so that the exhaust gas sensors 15 are always surrounded by scavenging air when the scavenging air device 45 is active. The scavenging air is disposed of via the exhaust gas flow.

As part of a method for operating the exhaust gas aftertreatment device 3, it is provided that the exhaust gas aftertreatment device 3 is operated in an aftertreatment position or in a rest position depending on at least one operating parameter, preferably depending on a geographic location at which the method is carried out. In the aftertreatment position, an exhaust gas flow is passed through the at least one exhaust gas aftertreatment element 11, and the at least one exhaust gas sensor 15 is acted upon by the exhaust gas flow. In the rest position, the exhaust gas flow is routed past the at least one exhaust gas aftertreatment element 11, leaving out the latter, and the at least one exhaust gas sensor 15 is shielded from the exhaust gas flow.

4 shows a schematic representation of an embodiment of such a method for operating an exhaust gas aftertreatment device 3 4A a first part method, and 4B shows a second partial method.

The first part method according to 4A is initiated under a first condition B1, which is met when the exhaust gas aftertreatment device 3 is operated in an emission-regulated area, which is referred to here as IMO3 operation. In this case, the method starts in a first step S1. In a second step S2, a check is made as to whether an exhaust gas flap 23 referred to as “EGN flap” and assigned to the actuating device 21 is open towards the exhaust gas aftertreatment element 11 . If this is not the case, the corresponding exhaust flap 23 is opened in a third step S3. In a fourth step S4, a check is then carried out to determine whether an exhaust gas flap 23 which is associated with the adjusting device 21 and leads into the bypass path 19 is closed. If this is not the case, this exhaust flap 23 is closed in a fifth step S5.

In a sixth step S6, it is then checked whether the scavenging air device 45 is activated, ie the fluidic connection between the scavenging air source 47 and the sensor chamber 35 is released. If this is the case, the scavenging air device 45 is deactivated in a seventh step S7, ie the fluidic connection between the scavenging air source 47 and the sensor chamber 35 is blocked. In that regard, the presentation refers to 4 according to the second exemplary embodiment of the sensor arrangement 29 3 . However, it is easily possible to use the method corresponding to the first exemplary embodiment of the sensor arrangement 29 according to FIG 2 to be adapted, in particular in that instead of the scavenging air device 45 the valve device 39 is activated accordingly.

Optionally, in an eighth step S8, a check is then carried out to determine whether a preheating mode is active for at least one of the exhaust gas sensors 15. If this is the case, the preheating mode is deactivated in a ninth step S9.

Then, in a tenth step S10, it is checked whether a supply of reducing agent, in particular a supply of urea, to exhaust gas aftertreatment element 11 is active. If this is not the case, the supply of reducing agent is activated in an eleventh step S11.

Then, in a twelfth step S12, it is checked whether condition B1 is still present; if this is the case, the method is continued in the first step S1. If, on the other hand, the first condition B1 is no longer present, it is concluded that a second condition B2 is present, which is met when the exhaust gas aftertreatment device 3 is operated in a non-emission-regulated range, which is referred to as IMO2 operation.

In this case, the procedure with the second part procedure is in accordance with 4B continued in a thirteenth step S13.

Then, in a fourteenth step S14, it is checked whether the supply of reducing agent is active. If this is the case, it is deactivated in a fifteenth step S15. Then, in a sixteenth step S16, it is checked whether the scavenging air device 45 is active. If this is not the case, the scavenging air device 45 is activated in a seventeenth step S17. Then, in an eighteenth step S18, it is checked whether the exhaust gas valve 23 leading to the bypass path 19 is open. If this is not the case, this exhaust flap 23 is opened in a nineteenth step S19. Then, in a twentieth step S20, it is checked whether the exhaust gas flap 23 leading to the exhaust gas aftertreatment element 11 is closed. If this is not the case, this exhaust flap 23 is closed in a twenty-first step S21.

Optionally, in a twenty-second step S22, it is then checked whether the preheating mode for the at least one exhaust gas sensor 15 is active. If this is not the case, the preheating mode is activated in a twenty-third step S23.

Then, in a twenty-fourth step S24, it is checked whether the second condition B2 is still met. If this is the case, the method continues in the thirteenth step S13. If, on the other hand, this is not the case, it is assumed that the first condition B1 is now once again met, and the method is carried out correspondingly with the first partial method 4A continued in the first step S1.

The method is preferably carried out continuously and permanently during operation of the internal combustion engine 1 .

Claims (10)

Sensor arrangement (29) for determining at least one exhaust gas parameter in an exhaust gas flow, with - a housing (31), which has an exhaust gas guide section (33) and a sensor chamber (35), in which at least one exhaust gas sensor (15) is arranged, wherein - the housing (31) is set up to an exhaust pipe section (7) of an exhaust line (8) for determining the at least one exhaust para meters in the exhaust pipe section (7), wherein - the sensor arrangement (29) has a shielding device (25) which can be moved optionally into a shielding position and a release position, wherein - the shielding device (25) is set up to release position a fluidic connection between the exhaust gas guide section (33) and the sensor chamber (35) in such a way that during operation of the sensor arrangement (29) exhaust gas flows from the exhaust gas guide section (33) into the sensor chamber (35) to the at least one exhaust gas sensor (15 ) can reach, and wherein - the shielding device (25) is set up to shield the sensor chamber (35) from the exhaust gas routing section (33) in the shielding position in such a way that no exhaust gas reaches the at least one exhaust gas sensor during operation of the sensor arrangement (29). (15) can arrive. Sensor arrangement (29) after claim 1 , wherein the shielding device (25) has a valve device (39) which is arranged and set up to release the fluidic connection between the exhaust gas guide section (33) and the sensor chamber (35) in the release position and to block it in the shielding position. Sensor arrangement (29) according to one of the preceding claims, wherein the shielding device (25) has a scavenging air device (45), wherein the scavenging air device (45) has a scavenging air source (47) which is connected to the housing (31), in particular to the sensor chamber (35) can be fluidically connected, the scavenging air device (45) being set up to fluidly connect the scavenging air source (47) to the sensor chamber (35) in the shielding position, so that the sensor chamber (35) moves in the direction of the exhaust gas routing section (33). Purge air flows through, and wherein the purge air device (45) is set up to fluidically separate the purge air source (47) in the release position from the sensor chamber (35). Sensor arrangement (29) according to one of the preceding claims, wherein the at least one exhaust gas sensor (15) is selected from a group consisting of: a nitrogen oxide sensor and an ammonia sensor. Exhaust gas aftertreatment device (3) for the in particular catalytic aftertreatment of an exhaust gas flow, with an exhaust pipe section (7), the exhaust pipe section (7) having an aftertreatment section (9) with at least one exhaust gas aftertreatment element (11) and a sensor section (13) arranged downstream of the aftertreatment section (9). has at least one exhaust gas sensor (15), wherein - the exhaust gas after-treatment device (3) has a bypass path (19) which opens out of the exhaust pipe section (7) upstream of the after-treatment section (9) and again into the exhaust pipe section (7) between the after-treatment section (9) and the sensor section (13), wherein - the exhaust gas after-treatment device (3) has an actuating device (21) which is set up in order, in a first functional position, to guide an exhaust gas flow through the after-treatment section (9) into the sensor section (13) and to block the bypass path (19), and in a second functional position to guide the exhaust gas flow through the bypass path (19) into the sensor section (13) and to block the after-treatment section (9), wherein - the exhaust gas aftertreatment device (3) has a shielding device (25) which is set up to optionally allow exhaust gas to flow against the at least one exhaust gas sensor (15) or to shield the at least one exhaust gas sensor (15) from exhaust gas, and wherein - the exhaust gas aftertreatment device (3) also has a control device (27), which is operatively connected to the adjusting device (21) and to the shielding device (25) and is set up to move the adjusting device (21) selectively into the first functional position and into the second functional position switch, and to control the shielding device (25) in such a way that in the first functional position, exhaust gas is permitted to flow against the at least one exhaust gas sensor (15), and that in the second functional position the at least one exhaust gas sensor (15) is shielded from exhaust gas. Exhaust aftertreatment device (3). claim 5 , wherein the exhaust aftertreatment device (3) has a sensor arrangement (29) according to one of Claims 1 until 4 wherein the control device (27) is operatively connected to the sensor arrangement (29) and set up to move the shielding device (25) of the sensor arrangement (29) into the release position when the actuating device (21) is in the first functional position and in the second To switch functional position of the actuating device (21) in the shielding position. Internal combustion engine (1), with at least one sensor arrangement (29) according to one of Claims 1 until 4 , or with an exhaust aftertreatment device (3) according to one of Claims 5 or 6 . Vehicle (2), in particular a ship, with an internal combustion engine (1). claim 7 . Method for operating an exhaust gas aftertreatment device (3), wherein the exhaust gas aftertreatment device (3) is operated in an aftertreatment position or in a rest position depending on at least one operating parameter, wherein in the aftertreatment position an exhaust gas flow is passed through at least one exhaust gas aftertreatment element (11) and at least one exhaust gas sensor (15 ) downstream of the at least one exhaust gas after-treatment element (11) is acted upon by the exhaust gas flow, and wherein in the rest position the exhaust gas flow is guided past the at least one exhaust gas after-treatment element (11) while leaving out the at least one exhaust gas after-treatment element (11) and the at least one exhaust gas sensor (15) of is shielded from the exhaust gas flow. procedure after claim 9 , wherein a geographic location at which the method is carried out is used as the at least one operating parameter.

Images