DE102022214201A1 - Method for operating a system for supplying air to a burner - Google Patents

Abstract

Method for operating a system (40) for supplying air to a burner (43), in particular for conditioning a catalyst (37), which is designed, for example, as a three-way catalyst, wherein a pump (58) conveys air between an air inlet (46) in the system (40) and the burner (43), wherein a sensor element (55) is arranged between the air inlet (46) and the pump (58), by means of which a property present there - in particular a temperature (T55) - of the air is detected, wherein after activation of the system (40) in a step (S1) the property of the air in the system (40) is detected by means of the sensor element (55).

Description

State of the art

It is known that the use of three-way catalysts is necessary to achieve emission limits. Such emission limits are determined, for example, by the EU emissions standard EU6. These three-way catalysts enable the conversion of the relevant gaseous pollutants, such as nitrogen oxide NOx, hydrocarbons HC and carbon monoxide CO into harmless products such as nitrogen N2, water H2O and carbon dioxide CO2. In order for the catalytic reactions required for this to take place, the temperature in the catalyst, the so-called light-off temperature, must exceed typically 300°C to 400°C. As soon as this temperature is reached, the catalyst converts the relevant pollutants almost completely. In order to achieve this state as quickly as possible, so-called internal engine catalyst heating measures are already being used. These internal catalyst heating measures change the efficiency of the internal combustion engine (particularly the gasoline engine) by, for example, retarding the ignition angle in such a way that the exhaust gas temperature and the so-called enthalpy input into the catalyst are increased. At the same time, intelligent injection strategies (e.g. multiple injections) ensure stable combustion. The test cycles that have been valid to date (NEDC, FDP 75), which all begin with an extended idling phase, have ensured a rapid light-off temperature with low emissions.

In addition to these internal engine catalyst heating measures, external engine catalyst heating measures have also been investigated in the past. These include, for example, electrically heated catalysts, but also so-called exhaust gas burners, such as those described in the published documents DE 41 32 814 A1 and DE 195 04 208 A1 are known.

In connection with the exhaust emission standards that have been in force up to now, it was still possible to comply with them solely by means of internal catalytic converter heating measures, despite the increasingly strict requirements in the past. For this reason, the external catalytic converter heating measures mentioned above, such as the electrically heated catalytic converter or the exhaust gas burner, or burner for short, have not yet been able to establish themselves on the market. With the introduction of the determination of emissions that are determined during real road trips (real driving emissions, RDE), driving situations in which the conversion of various exhaust gas components by the three-way catalytic converters mentioned above is not possible solely by means of internal catalytic converter heating measures are becoming more important. These so-called RDE boundary conditions also include, for example, the so-called urban spontaneous cold start of a motor vehicle, which can take place with a high engine load in combination with a very short idling phase beforehand. Such real driving conditions push the familiar internal catalyst heating to its limits, especially when further reduced emission limits are to be expected at the same time, which must be complied with. This is expected for the EU emissions standard EU7, for example. In connection with these requirements, a so-called exhaust gas burner turns out to be an extremely effective measure. Using such an exhaust gas burner, it is possible to bring a three-way catalyst extremely quickly to the aforementioned light-off temperature, at which the pollutants are converted very early.

Embodiments of the invention

According to a first embodiment of the invention, a method is provided for operating a system for supplying air to a burner, in particular for conditioning a catalyst. The conditioning of the catalyst results in it being preferably heated up and a temperature of the catalyst being set, in particular a working temperature or conversion temperature. The catalyst is designed in particular as a three-way catalyst or four-way catalyst (a combination of a three-way catalyst and a gasoline particle filter). A pump that delivers air is arranged between an air inlet in the system and the burner. A sensor element is arranged between the air inlet and the pump, by means of which a property of the air present there is detected.

According to a further aspect, it is provided that after activation of the system, the properties of the air in the system are detected in one step by means of the sensor element.

According to a further aspect of the invention, a change in the property over time is to be determined in one step from a temporal progression of the property of the air. By observing the temporal progression, it is possible to determine unusual increases and, for example, to conclude that there is a defect in the system.

According to a further aspect, it is planned to change the to compare the property over time with a reference value.

If the change in the property over time exceeds a threshold value of the comparison value, it can be safely concluded that there is a defect in the system.

According to a further embodiment, it is provided that a temperature is determined by means of one sensor element and a temperature is determined by means of the other sensor element and if a temperature difference exceeds a temperature threshold value, a defect in the system is concluded.

Furthermore, a computer program is provided which is designed to carry out all the steps of one of the methods mentioned, such that it is programmed such that it carries out a method when it is executed on a computer.

Furthermore, a machine-readable storage medium is provided on which the computer program is stored or which is stored for use in a method. Furthermore, a control device is provided which is designed in such a way that all steps of one of the methods are carried out or that it is programmed for use in a method.

• 1 eine schematische Ansicht der Anlage zur Zuführung von Luft zu einem Brenner,
• 2 eine schematische Darstellung des erfindungsgemäßen Verfahrens.

The invention is explained in more detail below with reference to the two figures shown. They show:

• 1 a schematic view of the system for supplying air to a burner,
• 2 a schematic representation of the method according to the invention.

In 1 a device 10 is shown which is particularly intended for a motor vehicle. This device 10 has an internal combustion engine 13 which is supplied with air via an intake device 16. This intake device 16 has an air inlet 19. In the air supply to the internal combustion engine 13 there is also a sensor element 22 and then a valve 25, which is typically designed as a so-called throttle valve. The air inlet 19 typically leads into a so-called box 28 (air filter box), so that the admitted air first flows through the air inlet 19 and then flows through an air filter (not described in more detail here). The intake device 16 has an intake pipe 31 in which the aforementioned sensor element 22 is arranged. The valve 25 is also arranged in this intake pipe 31. The exhaust gases or combustion gases generated by the internal combustion engine 13 are introduced into an exhaust system 34. One part of this exhaust system is, for example, a catalyst 37. After passing through the catalyst 37, the converted exhaust gases are released into the environment (arrow) or - depending on the exhaust system - this exhaust gas flows through other components/organs of the exhaust system that change the exhaust gas.

In 1 Furthermore, a system 40 for supplying air to a burner 43 is shown. This system 40 also has an air inlet 46, which represents an entrance to a box 49. An air filter can also be arranged in this box 49. The boxes 28, 49 can also be designed as one box, as is symbolically shown by the dashed rectangle around both boxes 28, 49 without any further designation. Accordingly, such a combined box can also have only one air inlet, which combines the two air inlets 19, 46. In addition, such a box can also have only a single air filter, which represents the two air filters mentioned above. The air passing through the air inlet 46 into the box 49 then enters an intake pipe 52, in which a sensor element 55 is also arranged. The sensor element 55 can, for example, be designed as a sensor element for detecting temperature. If this sensor element 55 is, for example, part of a so-called hot film measuring probe, then in addition to the air mass flow, this can be used, for example, as a whole to determine the pressure, temperature and humidity of the air. The incoming air then passes through a pump 58 and is fed by this pump 58 to a valve 61 (shut-off valve). This valve 61 serves - as the name suggests - to shut off the air supply to the burner 43. In a section of the system 40 between the pump 58 and the valve 61 there is a further sensor element 64 which can be designed, for example, as a sensor element for detecting pressure or as a sensor element for detecting temperature. The sensor element 22 can be designed in the same way as the sensor element 55. In the flow direction after the burner 43, a mechanical component is shown which is, for example, a screw connection with flanges. The device 10 shown here also has a control unit 70, which is connected to individual components of this device 10 via signal lines, which are not described in more detail here. These signal lines are used for communication between the individual components and the control unit 70. This control unit has a machine-readable storage medium 73, on which, for example, a computer program 76 is stored.

As part of the method presented here for operating a system 40 for supplying air to the burner 43, in particular for conditioning a catalyst 37, which is designed in particular as a three-way catalyst or as a four-way catalyst, it is provided that the pump 58 conveys air between an air inlet 46 in the system 40 and the burner 43. A sensor element 55 is arranged between the air inlet 46 and the pump 58, by means of which a property present or applied there - in particular a temperature T55 - of the air is detected.

In the context of the procedure, cf. 2 , it is provided in a step S1 that after activation of the system 40 in a step S1, the property of the air in the system 40 is recorded by means of the sensor element 55, in particular over a time course. For example, in a switching state in which the pump 58 is turned off, i.e. no air is being pumped to the burner 43, the property of the air is recorded. This property of the air can be, for example, a temperature T55, which in this turned off state of the pump 58 is referred to as temperature T550. If the pump 58 is turned on, this sensor element 55 also determines a property of the air in the system 40, in this case, for example, a temperature T55_1 over the time course. The method also includes a step S3 in which the change in the property over time is compared with a comparison value DT/Dt. If the change in the property over time exceeds a threshold value TSCH of the comparison value DT/Dt, a defect in the system 40 is concluded.

Depending on the technical condition of the system 40 (OK or defective), a different temperature development can occur in the system 40. For example, in a system 40 that is in a technically perfect condition, the temperature T55 may only increase slightly over a certain period of time because, for example, the intake pipe 52 is arranged in a so-called engine compartment that is heated by radiant heat from the internal combustion engine 13, but the effect of the heating is only limited by the constantly freshly sucked-in air, in a system 40 that is in a technically defective condition, for example due to a leak in the intake pipe 52 or a loose pipe connection on the intake pipe 52, so-called secondary air can be sucked in from the engine compartment, for example. Since such air is typically significantly warmer than air sucked in from the environment, an increased T55 will be detected by a sensor element 55 in the aforementioned defect case. If in such a case, for example, a temperature T22 is determined by means of the sensor element 22 and a temperature T55 is determined by means of the other sensor element 55 and a temperature difference DT5522 exceeds a temperature threshold value TSCH, it is concluded that there is a defect in the system 40.

In the above example, the temperature difference DT5522 is determined, which results when a temperature T22, T55 is determined at two different locations (location of the sensor element 22, location of the sensor element 55) and a difference between these temperatures T22, T55 is formed. In a further embodiment, for example, the sensor element 22 can detect a temperature of the surroundings of the motor vehicle or the device 10. A corresponding temperature difference DT5522 can also be determined for this case. If a temperature difference DT5522 exceeds a temperature threshold value TSCH, a defect in the system 40 is concluded.

Furthermore, a computer program 76 is provided which is designed such that it carries out all the steps of one of the aforementioned methods, or which is programmed such that a method is carried out when it is carried out on a computer. In addition, the aforementioned machine-readable storage medium 73 is provided on which the computer program 76 is stored, or on which the computer program 76 is stored for use in one of the aforementioned methods. The control unit 70 is designed such that all the steps of one of the aforementioned methods can be carried out, or that it is programmed for use in a method.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed 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 accepts no liability for any errors or omissions.

Cited patent literature

• DE 4132814 A1 [0002]
• DE 19504208 A1 [0002]

Claims (8)

Method for operating a system (40) for supplying air to a burner (43), in particular for conditioning a catalyst (37), which is designed, for example, as a three-way catalyst, wherein a pump (58) conveys air between an air inlet (46) in the system (40) and the burner (43), wherein a sensor element (55) is arranged between the air inlet (46) and the pump (58), by means of which a property present there - in particular a temperature (T55) - of the air is detected, wherein after activation of the system (40) in a step (S1) the property of the air in the system (40) is detected by means of the sensor element (55). Procedure according to Claim 1 , characterized in that in a step (S2) a change in the property of the air over time is determined from a temporal progression of the property of the air. Procedure according to Claim 2 , characterized in that in a step (S3) the change in the property over time is compared with a comparison value (DT/Dt, T22). Procedure according to Claim 2 or 3 , characterized in that if the change in the property over time exceeds a threshold value of the comparison value (DT/Dt), a defect in the system (40) is concluded. Procedure according to Claim 1 , characterized in that a temperature (T22) is determined by means of the sensor element (22) and a temperature (T55) is determined by means of the other sensor element (55), and if a temperature difference (DT5522) exceeds a temperature threshold value (TSCH), a defect in the system (40) is concluded. Computer program (76) which is designed to carry out all the steps of one of the methods according to one of the Claims 1 until 5 or that it is programmed in such a way that it carries out a method according to any of the Claims 1 until 5 when run on a computer. Machine-readable storage medium (73) on which the computer program (76) according to Claim 6 or that the computer program (76) is stored on it according to Claim 6 for use in a procedure of Claims 1 until 5 is saved. Control device (70) which is designed to carry out all the steps of one of the methods according to one of the Claims 1 until 5 or that it is intended for use in a procedure under any of the Claims 1 until 5 is programmed.

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