EP4043792A1 - Method and arrangement for the use of combustion products or properties of the air in the combustion air path of a gas-fired heater for its control and / or state analysis - Google Patents
Method and arrangement for the use of combustion products or properties of the air in the combustion air path of a gas-fired heater for its control and / or state analysis Download PDFInfo
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- EP4043792A1 EP4043792A1 EP22151795.6A EP22151795A EP4043792A1 EP 4043792 A1 EP4043792 A1 EP 4043792A1 EP 22151795 A EP22151795 A EP 22151795A EP 4043792 A1 EP4043792 A1 EP 4043792A1
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- exhaust gas
- property
- sensor
- humidity
- air
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Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/003—Systems for controlling combustion using detectors sensitive to combustion gas properties
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/24—Preventing development of abnormal or undesired conditions, i.e. safety arrangements
- F23N5/242—Preventing development of abnormal or undesired conditions, i.e. safety arrangements using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2202/00—Fluegas recirculation
- F23C2202/10—Premixing fluegas with fuel and combustion air
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2202/00—Fluegas recirculation
- F23C2202/50—Control of recirculation rate
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2221/00—Pretreatment or prehandling
- F23N2221/12—Recycling exhaust gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2223/00—Signal processing; Details thereof
- F23N2223/10—Correlation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2225/00—Measuring
- F23N2225/26—Measuring humidity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2231/00—Fail safe
- F23N2231/18—Detecting fluid leaks
Definitions
- the invention relates to a method and an arrangement for using measured values of components or properties, in particular the humidity, of the air in the combustion path of a gas-fired heating device for its regulation and/or status analysis.
- gas-fired heaters In gas-fired heaters, electronically controlled gas-air combinations are used which, as part of a closed control circuit, use controlled variables such as an ionization current that can be measured during combustion, which correlate with a defined gas-air ratio.
- controlled variables such as an ionization current that can be measured during combustion, which correlate with a defined gas-air ratio.
- the correlation is subject to the influence of disturbance variables, which means that the resulting gas-air mixture can deviate from the target value in the adjusted state, which is evaluated in the context of tolerance analyzes and taken into account when defining operating limits.
- the invention deals in particular with the detection or measurement of selected disturbance variables and, based on this, offers concepts of how the detection of a disturbance variable in conjunction with knowledge of its influence on the gas-air mixture can be used for more robust and extended device operation.
- the totality of all relevant influences on the target gas-air mixture are realistically combined and a deviation related to a constant heating load is assigned to the mixture.
- influences on the mixture formation can have a particularly destabilizing effect on the combustion to be initiated and make a complex ignition algorithm with multiple ignition attempts and additional thermoacoustic disturbances necessary.
- the qualitative and/or quantitative knowledge of disturbance variables in heating operation and their specific influence on the formation of the gas-air mixture can reduce the tolerance bands that are to be assumed, which means there is significant potential for optimization.
- this knowledge can also be used to detect and display (e.g. in a control panel as part of device commissioning) leakage flows between the exhaust gas path and the combustion air path (fresh air supply) resulting from installation errors when laying exhaust gas-air piping or, for example, from wear and tear or growth of an exhaust pipe can result.
- the object of the present invention is to at least partially solve the problems described with reference to the prior art.
- the object of the invention is to create a method and an arrangement for using properties of the air in the combustion air path of a gas-fired heating device for its control and/or status analysis.
- Contributing to this is a method for using at least one property of the air in a combustion air path of a gas-fired heater to measure exhaust gas recirculation and to control it and/or analyze its status, with the property being measured using at least one sensor and its behavior in relation to known processes in the heater being taken into account Empirical values or calibration data is compared, so that changes in the property are recognized and used (can be) to control the heater and/or to report status.
- the measured property of the air is used to measure an exhaust gas recirculation. Flue gas recirculation affects the properties of the air in the combustion air path and therefore allows conclusions to be drawn about possible leaks and the composition of the air in general.
- the combustion air path of a gas-fired heater may be, for example, a section of duct located in a section from an air intake towards the burner or combustion chamber. It is possible that essentially only combustion air should or is conveyed in the combustion air path in which the property is measured.
- the combustion air path can be part of an exhaust gas recirculation system, i.e. a section in which air is fed (again) to the burner together with recirculated exhaust gas from the combustion chamber.
- the behavior of the property e.g. B. with regard to measured mean values, limit values, vibrations, etc., can be related to desired, predetermined empirical values or calibration data that are stored, for example, in a data memory and/or can be called up automatically.
- Empirical values can include, for example, mean values and tolerance ranges for the behavior of the property, which can also be adapted system-specifically via the history of the gas-fired heating device if necessary.
- Calibration data can be fixed and/or variably adjustable reference values for the gas-fired heating device, which can be specified or set during commissioning and/or with the duration of operation.
- changes that indicate deviations from normal operation can also be detected. If an undesired or unexpected change/deviation of one of the properties is detected, it is possible, for example, to (automatically) intervene in the control of the heater, e.g. by initiating or executing measures to adjust the gas-air mixture formation and/or to influence the air will. It is possible that when such a change in the property is detected, (automatic) status reports are sent to the user, a control center, an evaluation unit, etc., which may further analyze this change and then trigger further measures on the heater.
- Fluctuations in the humidity contained in the combustion air (content of water vapor in the air) and/or the occurrence of flue gas recirculation, i.e. the Partial supply of exhaust gas to the combustion air, as permitted by local regulations up to certain limits, are normal environmental influences to be assumed or operating modes that are permitted up to specifiable limits, which behave like disturbance variables on the formation of the gas-air mixture and accordingly in the context of the tolerance analysis are taken into account. Since these two influences have the strongest effect on the mixture deviation, taking into account the current influences they emanate during operation has a particularly large potential for optimization.
- incorrectly installed or damaged exhaust gas/air piping can also be identified, the resulting leakage flow of which is above the permissible limits, because the effect can also be detected here on the humidity of the combustion air.
- the object of the invention is, by providing information about the combustion products contained in the combustion air path and possibly at other reference points (in the present example, the moisture, but can also be replaced by carbon dioxide, carbon monoxide, oxygen, nitrogen, nitrogen oxides, possibly in conjunction with the temperature or any combination of all of the above components) in connection with defined measurement methods or other signal processing methods (e.g. a cross-correlation) to record quantitatively and locally the current flue gas recirculation, among other things, and to detect a piping installation error or correct the gas-air mixture formation into account.
- the resulting reduction in tolerance limits for the air-gas mixture can be used to improve device performance and robustness.
- the measured property can preferably be at least one from the group of humidity, temperature, content of carbon dioxide, carbon monoxide, oxygen, nitrogen and nitrogen oxides. Since humidity sensors are part of a standard instrumentation belong, this property is preferably used, possibly in connection with the temperature at the measuring point.
- the humidity and/or the temperature of the air in the combustion path in front of a combustion chamber are measured and their progression over time is monitored and analyzed during an ignition process.
- the ignition process is a controlled process with precisely defined processes and parameters, so that it generates very specific courses of measured values and/or calculated values in a reproducible manner, a so-called signature, which can be stored in a control and regulation unit. With such a signature z. B. the course of the humidity in the combustion air path is correlated and the resulting correlation signal is analyzed.
- a cross-correlation of the time profile of the measured property to a time profile of at least one other measured value and/or parameter is particularly suitable, as a result of which a cross-correlated signal is generated that can be evaluated further.
- the humidity and/or the temperature at the location of the heating device can be used for correction from measuring sensors that are often already present or, for example, also from data services.
- the measurements described can not only be carried out passively during normal operation of the heater, but can also be carried out actively when starting and/or changes to settings are made in a targeted manner during operation of the heater and their effects on the measured values of the sensor are determined. This opens up further diagnostic options at times when they would not be possible during normal operation of the heater.
- An arrangement for using at least one property of the air (which changes with exhaust gas recirculation) in a combustion air path of a gas-fired heating device for measuring exhaust gas recirculation and for controlling it and/or analyzing its status, in particular for carrying out the method described, also serves to solve the task at least one sensor for measuring the property of the air is present in the combustion air path, which is connected to evaluation electronics that are set up to create and evaluate a correlated signal of the time profile of the property with the time profile of at least one other measured value and/or parameter.
- the evaluation electronics are set up to determine a current exhaust gas recirculation.
- the evaluation electronics are particularly preferably set up to determine the size and/or the location of a leak between an exhaust gas path and the combustion air path if the current recirculation deviates from empirical values and/or calibration data.
- the evaluation electronics are connected to a control and regulation unit and set up to transmit data about humidity, temperature and/or the current exhaust gas recirculation to it.
- the control and regulation unit can use current data for the properties in question and can use more precise regulation lower tolerances than with unknown properties of the air in the combustion air path.
- the heater has an exhaust gas recirculation system with an adjusting device, and the sensor is arranged downstream of a junction of the exhaust gas recirculation system in the combustion air path. This allows an exhaust gas recirculation to be set and/or changed in a targeted manner and the effect on the measured property of the air to be observed. In this way, additional information about the heater and the measuring systems used can be obtained.
- At least one humidity sensor and one temperature sensor are arranged at a measuring point as sensors.
- a further aspect also relates to instructions comprising a computer program product which cause the arrangement described to carry out the method described.
- the evaluation of the data measured by the sensor and their further use in the heater require a program and data for the analysis of the measured values, both of which must be updated from time to time.
- the explanations for the method can be used for a more detailed characterization of the arrangement, and vice versa.
- the arrangement can also be set up in such a way that the method is carried out with it.
- the use of at least one property of the air in a combustion air path of a gas-fired heater for its control and / or status analysis to increase safety during operation and / or to reduce tolerance limits in the control of a heater, so that this at least in some Conditions can be operated more efficiently and robustly.
- FIG. 1 shows schematically a heater 1, which z. B. is housed in an interior 4 of a building, not shown.
- Air fresh air
- Air passes from the free environment 2 through an air inlet 3 into the interior 4, from where it is sucked in as combustion air through an air intake 5 and guided to a combustion air path 21 (hatched).
- a vibration damper 6 Through a vibration damper 6, it reaches a mixing element 8, where a fuel gas from a fuel gas inlet 7 is mixed with the air.
- the resulting gas-air combination 22 (shown cross-hatched) reaches a combustion chamber 10 via a fan 9 (blower) in which the mixture of air and fuel gas is burned and the heat generated is dissipated for heating purposes.
- Combustion gases that arise are guided through an exhaust gas path 11 to an exhaust gas outlet 12 and released into the free environment 2 .
- an exhaust gas recirculation system 13 can branch off from the exhaust gas path 11 and feeds exhaust gas back to the gas-air compound 22 via a control device 14 via a junction 20 .
- a control and regulation unit 16 controls or regulates all processes taking place in the heating device 1 .
- a first sensor 17 for measuring a property of the combustion air is arranged at a suitable point in the combustion air path 21, 22 (the path of the gas-air compound is also considered here for the combustion air path). In the following, humidity is considered as a property to be measured, but the explanations would also apply to other properties of the air.
- the first sensor 17 is connected to evaluation electronics 15, which also have other signals and/or measured values available, for example from the control and regulation unit 16 or from a reference sensor 18 for measuring in the free environment 2. Additional sensors can be installed in the combustion air path 21, 22 can be arranged, for example a second sensor 19 for moisture measurement. The sensors 17, 18, 19 can also be combined sensors, for example for measuring humidity and temperature. The position of the second sensor 19 shown is required in the presence of an exhaust gas recirculation 13, so that the second sensor 19 can also measure changes caused by recirculated exhaust gas. The first sensor 17 is then not absolutely necessary.
- FIG. 2 illustrates the procedure for evaluating measurement signals from the first sensor 17 and/or the second sensor 19 in the evaluation electronics 15.
- Top left in 2 a symbolic diagram is shown in which the course of a first signal A (e.g. a fan speed when starting the heater 1) with a measured course of a second signal B (e.g. the humidity in the combustion air) in a cross-correlator K is correlated to a cross-correlated signal C (in a symbolic diagram lower right in 2 shown).
- the correlation can also detect or process a time offset S (shift) between the signals.
- exhaust gas path 11 of a heater 1 usually leads through the interior 4 in which the heater 1 is installed, leaks in the exhaust gas path 11 can inadvertently suck in exhaust gas with the combustion air, which can be detected by measuring the humidity. Exhaust gas can also get into the air inlet 3 from the exhaust gas outlet 12 of the heater 1 or possibly also from an adjacent (external) heater.
- FIG. 3 illustrates schematically and qualitatively which information e.g. B. can provide a simple moisture measurement.
- the moisture is plotted on the Y axis with any scale, and the time t is plotted on the X axis.
- the humidity is measured at the first sensor 17, there is a substantially constant value before the heater 1 starts, which when the heater 1 starts with a lead of the fan 9 at time V to the value Fu of the humidity in the open air Environment 2 set. Based on experience, this leads to a value within the hatched area and stays there. Without humidity measurement, the control of the heater would, as a precaution, take into account a tolerance range with a maximum possible humidity Fmax (dashed line), which is not necessary with the procedure described with humidity measurement.
- Fmax dashex
- the absolute air humidity or the expected stationary air humidity is measured after a defined period of inactivity of the heater 1 during the fan run-up and compared with the expected maximum air humidity Fmax, which can be based on our own measurements as well as on available weather data. If absolute humidity is determined during the measurement that exceeds the maximum value to be assumed (i.e. excessive humidity Fex), this can be taken as an indicator of external recirculation (exhaust gas introduction caused by the operation of another device and its unwanted exhaust gas recirculation to the device to be considered device) are used. Furthermore, the results of this humidity measurement during the fan run-up can be used as reference values for further measurements carried out during fired device operation and as the first recorded value in the context of a moisture-corrected gas-air mixture formation for ignition and device operation.
- the humidity F (measured at the first sensor 17 and/or at the second sensor 19) is again plotted on the Y axis against time t on the X axis.
- the humidity F (measured at the first sensor 17 and/or at the second sensor 19) is again plotted on the Y axis against time t on the X axis.
- the fan 9 starts to run ahead of time from point in time V, so that the ambient humidity is set first.
- the mixture is ignited, resulting in an increase in humidity after a certain time delay due to the recirculation of exhaust gas.
- the dotted curve Rnorm shows a normal course of the humidity in a typical operation with an approved recirculation.
- the dashed curve Rmax shows the value up to which recirculation (e.g. according to local regulations) is permitted.
- the first difference M1 between a first minimum (or a constant initial value) and a first maximum of the humidity readings in relation to a second difference M2 between the first maximum and a subsequent minimum (M1:M2) gives information about the amount of recirculated exhaust gas.
- typical changes resulting from exhaust gas recirculation of a signature based on stored empirical values allow e.g. B. during the ignition process in the measurements described and their evaluation, in particular through cross-correlation, conclusions about the location and/or quantity of a recirculation that occurs.
- FIG 5 further information can also be obtained after the ignition process when the heater 1 is in constant operation. This can be done by targeted changes during operation, particularly when there is an exhaust gas recirculation system 13 with an adjusting device 14. The effects of such a change for test purposes are shown in the dotted curve T as an example. In this way, empirical values can be gained with which later measured values can be compared. If an unexpected malfunction then occurs during operation, for example a sudden strong exhaust gas recirculation (curve Fex), the size of the measured malfunction can be compared with empirical values in order to be able to trigger suitable measures ranging from a warning message to a shutdown of heater 1.
- curve Fex sudden strong exhaust gas recirculation
- a heater 1 is ignited in a fixed scheme, which is stored in the control and regulation unit 16 by parameters (ignition speed of the fan 9, gas valve position or the like).
- this signature is known to the device electronics.
- the ignition signature known in this way can be examined with the aid of a sensor 17, 19 (for example a moisture sensor) in the combustion air path 21, 22, for example by means of cross-correlation. If there is sufficient coupling between the fresh air and the exhaust gas path 11 (eg due to a leak), the cross-correlation can prove the existence of the coupling and can also be used to locate a leak.
- a humidity can now be defined that correlates with a standard-related maximum permitted recirculation.
- both a characteristic signature caused by the ignition and a longer-term positive deviation in the moisture profile can be determined, which in turn provides input for gas-air mixture formation corrections or error or warning messages in comparison with the maximum allowed humidity.
- the measured signature can also provide conclusions about an existing exhaust gas recirculation and/or a recirculation amount and/or the location of the recirculation due to its characteristics (difference to the reference value and the local minima and maxima among each other) and the time of occurrence.
- signatures that are deliberately produced can also be used to evaluate the location and/or the amount of recirculation.
- a signature can be mapped in the exhaust gas or recirculated combustion air flow by changing the actuators involved in combustion (e.g. gas valve position, fan speed).
- a signature by influencing the condensation in a heating circuit is also possible and can be detected by changing the humidity in the combustion air path and evaluated on the basis of known correlations.
- the time and intensity of the measurement as well as the compression or stretching of the signature over time can be included in the evaluation.
- the recirculation detection with the help of signatures also offers the advantage that it can also correctly evaluate humidity values superimposed by external recirculation and assign it to a possible internal recirculation, as well as offering a redundant measurement method for measuring the absolute humidity.
- a beginning or ending external recirculation can be detected, which in turn can be used to trigger error or warning messages.
- the invention makes it possible to increase safety during operation and to reduce tolerance limits when controlling a heating device, so that it can be operated more efficiently and more robustly, at least under some conditions.
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Abstract
Die Erfindung betrifft ein Verfahren und eine Anordnung zur Verwendung mindestens einer Eigenschaft der Luft in einem Verbrennungsluftweg (21, 22) eines gasbefeuerten Heizgerätes (1) zur Messung einer Abgasrezirkulation und zu dessen Regelung und/oder Zustandsanalyse, wobei die Eigenschaft mittels mindestens eines Sensors (17, 19) gemessen und ihr Verhalten in Relation zu bekannten Abläufen im Heizgerät (1) mit Erfahrungswerten oder Kalibrierdaten verglichen wird, so dass Veränderungen der Eigenschaft erkannt und zur Regelung des Heizgerätes (1) und/oder zu Zustandsmeldungen genutzt werden können. Die Erfindung ermöglicht die Erhöhung der Sicherheit im Betrieb und eine Verringerung von Toleranzgrenzen bei der Regelung eines Heizgerätes (1), so dass dieses zumindest bei manchen Bedingungen effizienter und robuster betrieben werden kann.The invention relates to a method and an arrangement for using at least one property of the air in a combustion air path (21, 22) of a gas-fired heating device (1) to measure an exhaust gas recirculation and to regulate it and/or analyze its status, the property being measured by means of at least one sensor ( 17, 19) is measured and its behavior in relation to known processes in the heater (1) is compared with empirical values or calibration data, so that changes in the property can be detected and used to control the heater (1) and/or for status reports. The invention makes it possible to increase safety during operation and reduce tolerance limits when controlling a heating device (1), so that it can be operated more efficiently and more robustly, at least under some conditions.
Description
Die Erfindung betrifft ein Verfahren und eine Anordnung zur Verwendung von Messwerten von Bestandteilen bzw. Eigenschaften, insbesondere der Feuchtigkeit, der Luft im Verbrennungsweg eines gasbefeuerten Heizgerätes zu dessen Regelung und/oder Zustandsanalyse.The invention relates to a method and an arrangement for using measured values of components or properties, in particular the humidity, of the air in the combustion path of a gas-fired heating device for its regulation and/or status analysis.
In gasbefeuerten Heizgeräten kommen elektronisch geregelte Gas-Luft-Verbunde zum Einsatz, die als Bestandteil eines geschlossenen Regelkreises Regelgrößen, wie beispielsweise einen bei der Verbrennung messbaren lonisationsstrom, verwenden, die mit einem definierten Gas-Luft-Verhältnis korrelieren. Die Korrelation unterliegt dem Einfluss von Störgrößen, was zur Folge hat, dass das entstehende Gas-Luft-Gemisch im eingeregelten Zustand vom Zielwert abweichen kann, was im Rahmen von Toleranzanalysen bewertet und bei der Definition von Betriebsgrenzen berücksichtigt wird.In gas-fired heaters, electronically controlled gas-air combinations are used which, as part of a closed control circuit, use controlled variables such as an ionization current that can be measured during combustion, which correlate with a defined gas-air ratio. The correlation is subject to the influence of disturbance variables, which means that the resulting gas-air mixture can deviate from the target value in the adjusted state, which is evaluated in the context of tolerance analyzes and taken into account when defining operating limits.
Die Erfindung beschäftigt sich insbesondere mit der Detektion bzw. Messung ausgesuchter Störgrößen und bietet darauf aufbauend Konzepte, wie die Detektion einer Störgröße im Zusammenhang mit der Kenntnis um ihren Einfluss auf das Gas-Luft-Gemisch zu einem robusteren und erweiterten Gerätebetrieb genutzt werden kann. Um den sicheren und robusten Betrieb gasbefeuerter Heizgeräte mit elektronisch geregeltem Gas-Luft-Verbund zu ermöglichen, wird in den oben genannten Toleranzanalysen die Gesamtheit aller relevanten Einflüsse auf das Ziel-Gas-Luft-Gemisch realitätsentsprechend kombiniert und eine, bezogen auf eine konstante Heizlast resultierende, Abweichung dem Gemisch zugeordnet.The invention deals in particular with the detection or measurement of selected disturbance variables and, based on this, offers concepts of how the detection of a disturbance variable in conjunction with knowledge of its influence on the gas-air mixture can be used for more robust and extended device operation. In order to enable the safe and robust operation of gas-fired heaters with an electronically controlled gas-air ratio, the totality of all relevant influences on the target gas-air mixture are realistically combined and a deviation related to a constant heating load is assigned to the mixture.
Die hierbei ermittelten Abweichungen des Gemischs beeinflussen direkt die Betriebsgrenzen des Heizgerätes, das im zulässigen Betriebsfeld beispielsweise marktentsprechende Emissionsgrenzen für Kohlenmonoxid und Stickoxide einhalten und thermoakustische Störungen ausschließen muss. Die beschriebenen Folgen von möglichen Gemisch-Abweichungen führen zu einem Eingrenzen des Betriebsfeldes, das durch die Nicht-Kenntnis der im Betrieb vorliegenden Störgrößen deren vollständigen Einfluss berücksichtigen muss, und somit notwendigerweise die Leistungsfähigkeit des Heizgerätes reduziert.The deviations in the mixture determined in this way have a direct impact on the operating limits of the heater, which must, for example, comply with market-specific emission limits for carbon monoxide and nitrogen oxides and exclude thermoacoustic interference in the permitted operating range. The consequences of possible mixture deviations described lead to a narrowing of the operating field, which, due to the lack of knowledge of the disturbance variables present during operation, has to take into account their full influence, and thus necessarily reduces the performance of the heater.
Des Weiteren können in besonders anfälligen Betriebsphasen, wie dem rein gesteuerten Zündvorgang, Einflüsse auf die Gemischbildung besonders destabilisierend auf die einzuleitende Verbrennung wirken und hierbei einen aufwändigen Zündalgorithmus mit mehrfachen Zündversuchen und hinzunehmenden thermoakustischen Störungen notwendig machen.Furthermore, in particularly sensitive operating phases, such as the purely controlled ignition process, influences on the mixture formation can have a particularly destabilizing effect on the combustion to be initiated and make a complex ignition algorithm with multiple ignition attempts and additional thermoacoustic disturbances necessary.
Grundsätzlich kann die qualitative und/oder quantitative Kenntnis von Störgrößen im Heizbetrieb und von deren konkretem Einfluss auf die Gas-Luft-Gemischbildung anzunehmende Toleranzbänder verkleinern, womit ein signifikantes Optimierungspotenzial verbunden ist. Zudem kann diese Kenntnis auch Verwendung beim Detektieren und Anzeigen (z.B. in einem Bedienfeld im Rahmen einer Geräteinbetriebnahme) von Leckage-Strömungen zwischen Abgasweg und Verbrennungsluftweg (Frischluftzuführung) finden, die aus Installationsfehlern beim Verlegen einer Abgas-Luft-Verrohrung oder z.B. aus Verschleiß oder Bewuchs eines Abgasrohres resultieren können.In principle, the qualitative and/or quantitative knowledge of disturbance variables in heating operation and their specific influence on the formation of the gas-air mixture can reduce the tolerance bands that are to be assumed, which means there is significant potential for optimization. In addition, this knowledge can also be used to detect and display (e.g. in a control panel as part of device commissioning) leakage flows between the exhaust gas path and the combustion air path (fresh air supply) resulting from installation errors when laying exhaust gas-air piping or, for example, from wear and tear or growth of an exhaust pipe can result.
Aufgabe der vorliegenden Erfindung ist es, die mit Bezug auf den Stand der Technik geschildeten Probleme wenigstens teilweise zu lösen. Insbesondere ist die Schaffung eines Verfahrens und einer Anordnung zur Verwendung von Eigenschaften der Luft im Verbrennungsluftweg eines gasbefeuerten Heizgerätes zu dessen Regelung und/oder Zustandsanalyse Aufgabe der Erfindung.The object of the present invention is to at least partially solve the problems described with reference to the prior art. In particular, the object of the invention is to create a method and an arrangement for using properties of the air in the combustion air path of a gas-fired heating device for its control and/or status analysis.
Zur Lösung dieser Aufgabe dienen ein Verfahren und eine Anordnung sowie ein Computerprogrammprodukt gemäß den unabhängigen Ansprüchen. Vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung sind in den jeweiligen abhängigen Ansprüchen angegeben. Die Beschreibung, insbesondere im Zusammenhang mit der Zeichnung, veranschaulicht die Erfindung und gibt weitere Ausführungsbeispiele an.A method and an arrangement as well as a computer program product according to the independent claims serve to solve this task. Advantageous refinements and developments of the invention are specified in the respective dependent claims. The description, in particular in connection with the drawing, illustrates the invention and specifies further exemplary embodiments.
Hierzu trägt ein Verfahren bei zur Verwendung mindestens einer Eigenschaft der Luft in einem Verbrennungsluftweg eines gasbefeuerten Heizgerätes zur Messung einer Abgasrezirkulation und zu dessen Regelung und/oder Zustandsanalyse, wobei die Eigenschaft mittels mindestens eines Sensors gemessen und ihr Verhalten in Relation zu bekannten Abläufen im Heizgerät mit Erfahrungswerten oder Kalibrierdaten verglichen wird, so dass Veränderungen der Eigenschaft erkannt, und zur Regelung des Heizgerätes und/oder zu Zustandsmeldungen genutzt werden (können). Dabei wird die gemessene Eigenschaft der Luft zur Messung einer Abgasrezirkulation verwendet. Eine Abgasrezirkulation wirkt sich auf die Eigenschaften der Luft im Verbrennungsluftweg aus und erlaubt daher Rückschlüsse auf eventuelle Leckagen und generell auf die Zusammensetzung der Luft.Contributing to this is a method for using at least one property of the air in a combustion air path of a gas-fired heater to measure exhaust gas recirculation and to control it and/or analyze its status, with the property being measured using at least one sensor and its behavior in relation to known processes in the heater being taken into account Empirical values or calibration data is compared, so that changes in the property are recognized and used (can be) to control the heater and/or to report status. The measured property of the air is used to measure an exhaust gas recirculation. Flue gas recirculation affects the properties of the air in the combustion air path and therefore allows conclusions to be drawn about possible leaks and the composition of the air in general.
Der Verbrennungsluftweg eines gasbefeuerten Heizgerätes kann zum Beispiel ein Leitungsabschnitt sein, der in einem Abschnitt von einer Luftansaugung hin zum Brenner bzw. Brennraum angeordnet ist. Dabei ist möglich, dass in dem Verbrennungsluftweg, in dem eine Messung der Eigenschaft erfolgt, im wesentlichen nur Verbrennungsluft gefördert werden sollte bzw. wird. Der Verbrennungsluftweg kann Teil einer Abgasrückführung sein, also einem Abschnitt, in dem Luft gemeinsam mit rückgeführtem Abgas aus dem Brennraum (erneut) dem Brenner zugeführt wird. Das Verhalten der Eigenschaft, z. B. bezüglich gemessener Mittelwerte, Grenzwerte, Schwingungen, etc., kann in Bezug gesetzt werden zu gewünschten, vorgegebenen Erfahrungswerten oder Kalibrierdaten, die beispielsweise in einem Datenspeicher abgelegt und/oder automatisch abrufbar sind. Erfahrungswerte können zum Beispiel Mittelwerte und Toleranzfelder für das Verhalten der Eigenschaft umfassen, welche ggf. auch systemspezifisch über die Vergangenheit des gasbefeuerten Heizgerätes angepasst werden können. Kalibrierdaten können feste und/oder variabel einstellbare Richtwerte für das gasbefeuerte Heizgerät sein, die bei Inbetriebnahme und/oder mit der Dauer des Betriebes vorgegeben bzw. eingestellt werden können. Insbesondere können auch Veränderungen, die auf Abweichungen von einem Normalbetrieb hindeuten, erkannt werden. Wenn eine unerwünschte oder unerwartete Veränderung/Abweichung einer der Eigenschaft detektiert wird, kann beispielsweise (automatisch) in die Regelung des Heizgerätes eingegriffen werden, z.B. indem Maßnahmen zur Anpassung der Gas-Luft-Gemischbildung und/oder zur Einflussnahme auf die Luft eingeleitet bzw. ausgeführt werden. Es ist möglich, dass bei Feststellen einer solchen Veränderungen der Eigenschaft (automatisch) Zustandsmeldungen an den Nutzer, eine Zentrale, eine Auswerteeinheit etc. ausgelöst werden, die diese Veränderung ggf. weiter analysieren und dann weitere Maßnahmen am Heizgerät auslösen.The combustion air path of a gas-fired heater may be, for example, a section of duct located in a section from an air intake towards the burner or combustion chamber. It is possible that essentially only combustion air should or is conveyed in the combustion air path in which the property is measured. The combustion air path can be part of an exhaust gas recirculation system, i.e. a section in which air is fed (again) to the burner together with recirculated exhaust gas from the combustion chamber. The behavior of the property, e.g. B. with regard to measured mean values, limit values, vibrations, etc., can be related to desired, predetermined empirical values or calibration data that are stored, for example, in a data memory and/or can be called up automatically. Empirical values can include, for example, mean values and tolerance ranges for the behavior of the property, which can also be adapted system-specifically via the history of the gas-fired heating device if necessary. Calibration data can be fixed and/or variably adjustable reference values for the gas-fired heating device, which can be specified or set during commissioning and/or with the duration of operation. In particular, changes that indicate deviations from normal operation can also be detected. If an undesired or unexpected change/deviation of one of the properties is detected, it is possible, for example, to (automatically) intervene in the control of the heater, e.g. by initiating or executing measures to adjust the gas-air mixture formation and/or to influence the air will. It is possible that when such a change in the property is detected, (automatic) status reports are sent to the user, a control center, an evaluation unit, etc., which may further analyze this change and then trigger further measures on the heater.
Schwankungen der in der Verbrennungsluft enthaltenen Feuchte (Gehalt an Wasserdampf in der Luft) und/oder das Auftreten von Abgasrezirkulationen, also dem teilweisen Zuführen von Abgas zur Verbrennungsluft, wie sie nach lokalen Vorschriften bis zu gewissen Grenzen zulässig sind, sind regulär anzunehmende Umwelteinflüsse bzw. bis zu vorgebbaren Grenzen zulässige Betriebsarten, die sich auf die Gas-Luft-Gemischbildung wie Störgrößen verhalten und entsprechend im Rahmen der Toleranzanalyse berücksichtigt werden. Da diese beiden Einflüsse die stärkste Wirkung auf die Gemisch-Abweichung haben, hat die Berücksichtigung der von ihnen ausgehenden aktuellen Einflüsse im Betrieb ein besonders großes Optimierungspotenzial. Zudem können, wie zuvor dargestellt, auch falsch installierte oder beschädigte Abgas-Luft-Verrohrungen identifiziert werden, deren resultierende Leckage-Strömung oberhalb von zulässigen Grenzen liegen, weil sich hierbei der Effekt ebenfalls an der Feuchte der Verbrennungsluft detektieren lässt.Fluctuations in the humidity contained in the combustion air (content of water vapor in the air) and/or the occurrence of flue gas recirculation, i.e. the Partial supply of exhaust gas to the combustion air, as permitted by local regulations up to certain limits, are normal environmental influences to be assumed or operating modes that are permitted up to specifiable limits, which behave like disturbance variables on the formation of the gas-air mixture and accordingly in the context of the tolerance analysis are taken into account. Since these two influences have the strongest effect on the mixture deviation, taking into account the current influences they emanate during operation has a particularly large potential for optimization. In addition, as shown above, incorrectly installed or damaged exhaust gas/air piping can also be identified, the resulting leakage flow of which is above the permissible limits, because the effect can also be detected here on the humidity of the combustion air.
Gegenstand der Erfindung ist es, durch die Bereitstellung von Informationen über die im Verbrennungsluftweg und möglicherweise an weiteren Referenzpunkten enthaltenen Verbrennungsprodukte (im vorliegenden Beispiel die Feuchte, kann aber auch ersetzt werden durch Kohlendioxid, Kohlenmonoxid, Sauerstoff, Stickstoff, Stickoxide, gegebenenfalls in Verbindung mit der Temperatur oder eine beliebige Kombination aus allen genannten Bestandteilen) in Verbindung mit definierten Messverfahren bzw. weiteren Signalverarbeitungsverfahren (z.B. einer Kreuzkorrelation) unter anderem die aktuell vorliegende Abgasrezirkulation quantitativ sowie lokal zu erfassen und bei einer Verrohrungsinstallationsfehler-Detektion bzw. der Korrektur der Gas-Luft-Gemischbildung zu berücksichtigen. Die hieraus resultierende Verminderung von Toleranzgrenzen für das Luft-Gas-Gemisch kann zur Verbesserung der Geräteleistung und -robustheit genutzt werden.The object of the invention is, by providing information about the combustion products contained in the combustion air path and possibly at other reference points (in the present example, the moisture, but can also be replaced by carbon dioxide, carbon monoxide, oxygen, nitrogen, nitrogen oxides, possibly in conjunction with the temperature or any combination of all of the above components) in connection with defined measurement methods or other signal processing methods (e.g. a cross-correlation) to record quantitatively and locally the current flue gas recirculation, among other things, and to detect a piping installation error or correct the gas-air mixture formation into account. The resulting reduction in tolerance limits for the air-gas mixture can be used to improve device performance and robustness.
Wie erwähnt kann die gemessene Eigenschaft bevorzugt mindestens eine aus der Gruppe Feuchte, Temperatur, Gehalt an Kohlendioxid, Kohlenmonoxid, Sauerstoff, Stickstoff, und Stickoxiden sein. Da Feuchtesensoren zu einer üblichen Instrumentierung gehören, wird diese Eigenschaft, gegebenenfalls in Verbindung mit der Temperatur an der Messstelle bevorzugt verwendet.As mentioned, the measured property can preferably be at least one from the group of humidity, temperature, content of carbon dioxide, carbon monoxide, oxygen, nitrogen and nitrogen oxides. Since humidity sensors are part of a standard instrumentation belong, this property is preferably used, possibly in connection with the temperature at the measuring point.
Insbesondere werden die Feuchte und/oder die Temperatur der Luft im Verbrennungsweg vor einem Verbrennungsraum gemessen und ihr zeitlicher Verlauf während eines Zündvorganges überwacht und analysiert. Der Zündvorgang ist ein gesteuerter Vorgang mit genau festgelegten Abläufen und Parametern, so dass er reproduzierbar ganz bestimmte Verläufe von Messwerten und/oder berechneten Werten erzeugt, eine sogenannte Signatur, die in einer Steuer- und Regeleinheit gespeichert werden kann. Mit einer solchen Signatur kann z. B. der Verlauf der Feuchte im Verbrennungsluftweg korreliert und das entstehende Korrelationssignal analysiert werden.In particular, the humidity and/or the temperature of the air in the combustion path in front of a combustion chamber are measured and their progression over time is monitored and analyzed during an ignition process. The ignition process is a controlled process with precisely defined processes and parameters, so that it generates very specific courses of measured values and/or calculated values in a reproducible manner, a so-called signature, which can be stored in a control and regulation unit. With such a signature z. B. the course of the humidity in the combustion air path is correlated and the resulting correlation signal is analyzed.
Besonders geeignet ist die Bildung einer Kreuzkorrelation des zeitlichen Verlaufs der gemessenen Eigenschaft zu einem zeitlichen Verlauf mindestens eines anderen Messwertes und/oder Parameters, wodurch ein kreuzkorreliertes Signal erzeugt wird, das weiter ausgewertet werden kann.The formation of a cross-correlation of the time profile of the measured property to a time profile of at least one other measured value and/or parameter is particularly suitable, as a result of which a cross-correlated signal is generated that can be evaluated further.
Zur Erhöhung der Genauigkeit von Analysen aus einer gemessenen Eigenschaft der Luft ist es besonders sinnvoll, die gemessene Eigenschaft anhand von Umgebungsdaten zu korrigieren, wobei diese durch Messung in der Umgebung und/oder von anderen Datenquellen erlangt werden. So kann beispielsweise die Feuchte und/oder die Temperatur am Ort des Heizgerätes aus oft ohnehin vorhandenen Messfühlern oder aber beispielsweise auch von Datendiensten zur Korrektur herangezogen werden.In order to increase the accuracy of analyzes based on a measured property of the air, it is particularly useful to correct the measured property using environmental data, which is obtained through measurements in the environment and/or from other data sources. For example, the humidity and/or the temperature at the location of the heating device can be used for correction from measuring sensors that are often already present or, for example, also from data services.
Die beschriebenen Messungen können nicht nur passiv bei einem üblichen Betrieb des Heizgerätes durchgeführt werden, sondern es können auch aktiv bei einem Start und/oder während eines Betriebes des Heizgerätes gezielt Veränderungen von Einstellungen vorgenommen und deren Auswirkungen auf die Messwerte des Sensors ermittelt werden. Dies eröffnet weitere Diagnosemöglichkeiten zu Zeitpunkten, zu denen sie bei einem normalen Betrieb des Heizgerätes nicht möglich wären.The measurements described can not only be carried out passively during normal operation of the heater, but can also be carried out actively when starting and/or changes to settings are made in a targeted manner during operation of the heater and their effects on the measured values of the sensor are determined. This opens up further diagnostic options at times when they would not be possible during normal operation of the heater.
Zur Lösung der Aufgabe dient auch eine Anordnung zur Verwendung mindestens einer Eigenschaft der Luft (die sich mit einer Abgasrezirkulation verändert) in einem Verbrennungsluftweg eines gasbefeuerten Heizgerätes zur Messung einer Abgasrezirkulation und zu dessen Regelung und/oder Zustandsanalyse, insbesondere zur Durchführung des beschriebenen Verfahrens, wobei mindestens ein Sensor zur Messung der Eigenschaft der Luft im Verbrennungsluftweg vorhanden ist, der mit einer Auswerteelektronik verbunden ist, die eingerichtet ist, ein korreliertes Signal des zeitlichen Verlaufs der Eigenschaft mit dem zeitlichen Verlauf mindestens eines anderen Messwertes und/oder Parameters zu erstellen und auszuwerten. Außerdem ist die Auswerteelektronik eingerichtet, eine aktuelle Abgasrezirkulation festzustellen.An arrangement for using at least one property of the air (which changes with exhaust gas recirculation) in a combustion air path of a gas-fired heating device for measuring exhaust gas recirculation and for controlling it and/or analyzing its status, in particular for carrying out the method described, also serves to solve the task at least one sensor for measuring the property of the air is present in the combustion air path, which is connected to evaluation electronics that are set up to create and evaluate a correlated signal of the time profile of the property with the time profile of at least one other measured value and/or parameter. In addition, the evaluation electronics are set up to determine a current exhaust gas recirculation.
Besonders bevorzugt ist die Auswerteelektronik eingerichtet, bei Abweichung der aktuellen Rezirkulation von Erfahrungswerten und/oder Kalibrierdaten die Größe und/oder den Ort einer Leckage zwischen einem Abgasweg und dem Verbrennungsluftweg festzustellen.The evaluation electronics are particularly preferably set up to determine the size and/or the location of a leak between an exhaust gas path and the combustion air path if the current recirculation deviates from empirical values and/or calibration data.
In einer bevorzugten Ausführungsform ist die Auswerteelektronik mit einer Steuer- und Regeleinheit verbunden und eingerichtet, Daten über Feuchte, Temperatur und/oder aktuelle Abgasrezirkulation an diese zu leiten. Damit kann die Steuer- und Regeleinheit aktuelle Daten für die betreffenden Eigenschaften nutzen und eine genauere Regelung mit geringeren Toleranzen durchführen als bei unbekannten Eigenschaften der Luft im Verbrennungsluftweg.In a preferred embodiment, the evaluation electronics are connected to a control and regulation unit and set up to transmit data about humidity, temperature and/or the current exhaust gas recirculation to it. In this way, the control and regulation unit can use current data for the properties in question and can use more precise regulation lower tolerances than with unknown properties of the air in the combustion air path.
In einer besonderen Ausführungsform weist das Heizgerät eine Abgasrückführung mit einer Stelleinrichtung auf, und der Sensor ist stromabwärts einer Einmündung der Abgasrückführung im Verbrennungsluftweg angeordnet. Dies erlaubt es, gezielt eine Abgasrückführung einzustellen und/oder zu verändern und die Auswirkung auf die gemessene Eigenschaft der Luft zu beobachten. Auf diese Weise können zusätzliche Informationen über das Heizgerät und die eingesetzten Messsysteme gewonnen werden.In a special embodiment, the heater has an exhaust gas recirculation system with an adjusting device, and the sensor is arranged downstream of a junction of the exhaust gas recirculation system in the combustion air path. This allows an exhaust gas recirculation to be set and/or changed in a targeted manner and the effect on the measured property of the air to be observed. In this way, additional information about the heater and the measuring systems used can be obtained.
Um insbesondere nicht nur eine relative Feuchte, sondern auch die absolute Feuchte in der Luft messen zu können, was für die Regelung des Heizgerätes wichtig ist, sind als Sensor mindestens ein Feuchtesensor und ein Temperatursensor an einer Messstelle angeordnet.In order to be able to measure not only relative humidity but also absolute humidity in the air, which is important for controlling the heater, at least one humidity sensor and one temperature sensor are arranged at a measuring point as sensors.
Ein weiterer Aspekt betrifft auch ein Computerprogrammprodukt umfassende Befehle, die bewirken, dass die beschriebene Anordnung das beschriebene Verfahren ausführt. Die Auswertung der vom Sensor gemessenen Daten und deren weitere Verwendung im Heizgerät benötigen ein Programm und Daten für die Analyse der Messwerte, wobei beides gelegentlich aktualisiert werden muss.A further aspect also relates to instructions comprising a computer program product which cause the arrangement described to carry out the method described. The evaluation of the data measured by the sensor and their further use in the heater require a program and data for the analysis of the measured values, both of which must be updated from time to time.
Die Erläuterungen zum Verfahren können zur näheren Charakterisierung der Anordnung herangezogen werden, und umgekehrt. Die Anordnung kann auch so eingerichtet sein, dass damit das Verfahren durchgeführt wird.The explanations for the method can be used for a more detailed characterization of the arrangement, and vice versa. The arrangement can also be set up in such a way that the method is carried out with it.
Gemäß einem weiteren Aspekt wird die Verwendung mindestens einer Eigenschaft der Luft in einem Verbrennungsluftweg eines gasbefeuerten Heizgerätes zu dessen Regelung und/oder Zustandsanalyse zur Erhöhung der Sicherheit im Betrieb und/oder zur Verringerung von Toleranzgrenzen bei der Regelung eines Heizgerätes, so dass dieses zumindest bei manchen Bedingungen effizienter und robuster betrieben werden kann. Hinsichtlich bevorzugter Verwendungen wird auch auf die Erläuterungen zum Verfahren vollumfänglich Bezug genommen, insbesondere im Zusammenhang mit dem Auftreten von Abgasrezirkulationen.According to a further aspect, the use of at least one property of the air in a combustion air path of a gas-fired heater for its control and / or status analysis to increase safety during operation and / or to reduce tolerance limits in the control of a heater, so that this at least in some Conditions can be operated more efficiently and robustly. With regard to preferred uses, reference is also made in full to the explanations relating to the method, in particular in connection with the occurrence of exhaust gas recirculations.
Ein schematisches Ausführungsbeispiel der Erfindung, auf das diese jedoch nicht beschränkt ist, und die Funktionsweise des Verfahrens werden nun anhand der Zeichnung näher erläutert. Es stellen dar:
- Fig. 1:
- schematisch ein Heizgerät mit Sensor im Verbrennungsluftweg,
- Fig. 2:
- ein Diagramm zur Veranschaulichung des Prinzips der Kreuzkorrelation,
- Fig. 3:
- ein Diagramm zur Veranschaulichung eines ungewöhnlichen Verlaufs einer Feuchtemessung,
- Fig. 4:
- ein Diagramm zur Veranschaulichung von Verläufen einer Messung der Rezirkulation von Abgas und
- Fig. 5:
- ein Diagramm zur Veranschaulichung einer Testmessung und eines tatsächlichen Störfalles während des Betriebs eines Heizgerätes.
- Figure 1:
- schematic of a heater with a sensor in the combustion air path,
- Figure 2:
- a diagram to illustrate the principle of cross-correlation,
- Figure 3:
- a diagram to illustrate an unusual course of a moisture measurement,
- Figure 4:
- a diagram to illustrate curves of a measurement of the recirculation of exhaust gas and
- Figure 5:
- a diagram to illustrate a test measurement and an actual malfunction during the operation of a heater.
Grundlage aller Überlegungen hier ist die Tatsache, dass die (absolute) Feuchte der Verbrennungsluft eine wichtige Rolle für eine genaue Regelung der Verbrennung spielt. Allein die genaue Messung der Feuchte kann schon eine Regelung nach dem Stand der Technik verbessern. Noch wichtiger ist aber, dass das Abgas bei Verbrennung von Brenngasen (von Erdgas bis hin zu Wasserstoff) immer Wasserdampf, also Feuchtigkeit, enthält. Eine Feuchtemessung im Verbrennungsluftweg 21, 22 erlaubt daher auch einen Rückschluss auf die Menge an Abgas, das in der Verbrennungsluft möglicherweise enthalten ist (das gleiche gilt für mehrere andere messbare Eigenschaften des Abgases bzw. der Luft). Da der Abgasweg 11 eines Heizgerätes 1 meist durch den Innenraum 4, in dem das Heizgerät 1 aufgestellt ist, führt, kann bei Leckagen im Abgasweg 11 ungewollt Abgas mit der Verbrennungsluft angesaugt werden, was durch eine Feuchtemessung erkannt werden kann. Auch kann von dem Abgasaustritt 12 des Heizgerätes 1 oder möglicherweise auch von einem benachbarten (fremden) Heizgerät Abgas in den Lufteintritt 3 gelangen.All considerations here are based on the fact that the (absolute) humidity of the combustion air plays an important role in the precise control of combustion. The precise measurement of humidity alone can already improve state-of-the-art control. What is even more important, however, is that the exhaust gas from the combustion of combustible gases (from natural gas to hydrogen) always contains water vapour, i.e. moisture. A moisture measurement in the
Dazu wird die absolute Luftfeuchte bzw. die zu erwartende stationäre Luftfeuchte nach definierter Inaktivitätszeit des Heizgerätes 1 während des Lüftervorlaufs gemessen und mit der zu erwartenden maximalen Luftfeuchte Fmax, die sich sowohl auf eigene Messungen als auch auf zur Verfügung stehenden Wetterdaten stützen kann, abgeglichen. Werden im Rahmen der Messung absolute Feuchten ermittelt, die den maximal anzunehmenden Wert überschreiten (also eine exzessive Feuchte Fex), kann dies als Indikator für eine vorliegende Fremd-Rezirkulation (Abgaseinbringung bedingt durch den Betrieb eines anderen Gerätes und dessen ungewollte Abgasrückführung auf das zu betrachtende Gerät) herangezogen werden. Des Weiteren können Ergebnisse dieser Feuchtemessung während des Lüftervorlaufs als Referenzwerte für weitere im befeuerten Gerätebetrieb durchgeführte Messungen sowie als erster erfasster Wert im Rahmen einer Feuchte-korrigierten Gas-Luft-Gemischbildung für Zündung und Gerätebetrieb genutzt werden.For this purpose, the absolute air humidity or the expected stationary air humidity is measured after a defined period of inactivity of the
Gemäß
Die Zündung eines Heizgerätes 1 erfolgt in einem festeingestellten Schema, welches durch Parameter (Zünddrehzahl des Lüfters 9, Gasventilposition o.ä.) in der Steuer- und Regeleinheit 16 hinterlegt ist. Dadurch ist diese Signatur der Geräteelektronik bekannt. Die so bekannte Zündsignatur kann mit Hilfe eines Sensors 17, 19 (z.B. Feuchtesensor) im Verbrennungsluftweg 21, 22 z.B. mittels der Kreuzkorrelation untersucht werden. Sollte eine ausreichende Kopplung zwischen Frischluft und Abgasweg 11 (z.B. durch eine Leckage) vorliegen, kann die Kreuzkorrelation das Vorliegen der Kopplung nachweisen und des Weiteren für eine Leckageortung herangezogen werden.A
Alternativ kann basierend auf der zuvor erwähnten Referenzmessung der Luftfeuchte nach Lüfteranlauf nun eine Feuchte definiert werden, die mit einer normbedingten maximal erlaubten Rezirkulation korreliert. Nach erfolgter Zündung kann im Falle einer vorliegenden Rezirkulation sowohl eine durch die Zündung hervorgerufene, charakteristische Signatur als auch längerfristig eine positive Abweichung im Feuchteverlauf festgestellt werden, die dann wiederum Input für Gas-Luft-Gemischbildungskorrekturen oder Fehler- bzw. Warnmeldungen im Abgleich mit der maximal erlaubten Feuchte bietet. Jedoch kann auch die gemessene Signatur für sich allein durch ihre Ausprägung (Differenz zu Referenzwert sowie der lokalen Minima und Maxima untereinander) und dem Zeitpunkt des Auftretens Rückschlüsse auf eine vorliegende Abgasrezirkulation und/oder eine Rezirkulationsmenge und/oder den Ort der Rezirkulation bieten.Alternatively, based on the previously mentioned reference measurement of the air humidity after fan start-up, a humidity can now be defined that correlates with a standard-related maximum permitted recirculation. After ignition has taken place, in the event of recirculation, both a characteristic signature caused by the ignition and a longer-term positive deviation in the moisture profile can be determined, which in turn provides input for gas-air mixture formation corrections or error or warning messages in comparison with the maximum allowed humidity. However, the measured signature can also provide conclusions about an existing exhaust gas recirculation and/or a recirculation amount and/or the location of the recirculation due to its characteristics (difference to the reference value and the local minima and maxima among each other) and the time of occurrence.
Entsprechend der Auswertung der Startsignatur können auch bewusst herbeigeführte, definierte Signaturen zur Auswertung des Ortes und/oder der Menge der Rezirkulation genutzt werden.Corresponding to the evaluation of the start signature, defined signatures that are deliberately produced can also be used to evaluate the location and/or the amount of recirculation.
Konkret kann sich eine Signatur durch Änderung der an der Verbrennung beteiligten Aktuatoren (z.B. Gasventilposition, Lüfterdrehzahl) im Abgas bzw. rezirkuliertem Verbrennungsluftstrom abbilden lassen. Jedoch ist auch eine Signatur durch Einflussnahme auf die Kondensation in einem Heizkreislauf (bedingt durch kurzzeitige Änderung einer Rücklauftemperatur, der Gerätebelastung oder dem hydraulischen Modus) möglich und kann durch Änderung der Feuchte im Verbrennungsluftweg detektiert und auf Basis von bekannten Korrelationen ausgewertet werden.Specifically, a signature can be mapped in the exhaust gas or recirculated combustion air flow by changing the actuators involved in combustion (e.g. gas valve position, fan speed). However, a signature by influencing the condensation in a heating circuit (caused by a short-term change in a return temperature, the device load or the hydraulic mode) is also possible and can be detected by changing the humidity in the combustion air path and evaluated on the basis of known correlations.
Bei der Auswertung können sowohl Zeitpunkt und Intensität der Messung als auch zeitliche Stauchung bzw. Streckung der Signatur einbezogen werden.The time and intensity of the measurement as well as the compression or stretching of the signature over time can be included in the evaluation.
Die Rezirkulationsdetektion mit Hilfe von Signaturen bietet zudem den Vorteil, dass sie auch von Fremd-Rezirkulation überlagerte Feuchtigkeitswerte korrekt auswerten und einer möglichen eigenen Rezirkulation zuordnen kann, sowie ein redundantes Messverfahren zur Messung der absoluten Feuchte bietet.The recirculation detection with the help of signatures also offers the advantage that it can also correctly evaluate humidity values superimposed by external recirculation and assign it to a possible internal recirculation, as well as offering a redundant measurement method for measuring the absolute humidity.
Ändert sich die Feuchte der Verbrennungsluft im stationären Gerätebetrieb, bzw. stimmt die Änderung der Feuchte nicht mit dem gesteuerten Geräteverhalten überein, kann hierdurch eine beginnende oder endende Fremd-Rezirkulation erkannt werden, was wiederum zur Auslösung von Fehler- bzw. Warnmeldungen genutzt werden kann.If the humidity of the combustion air changes during stationary device operation, or if the change in humidity does not match the controlled device behavior, a beginning or ending external recirculation can be detected, which in turn can be used to trigger error or warning messages.
Die Erfindung ermöglicht die Erhöhung der Sicherheit im Betrieb und eine Verringerung von Toleranzgrenzen bei der Regelung eines Heizgerätes, so dass dieses zumindest bei manchen Bedingungen effizienter und robuster betrieben werden kann.The invention makes it possible to increase safety during operation and to reduce tolerance limits when controlling a heating device, so that it can be operated more efficiently and more robustly, at least under some conditions.
- 11
- Heizgerätheater
- 22
- Umgebungvicinity
- 33
- Lufteintrittair intake
- 44
- Innenrauminner space
- 55
- Luftansaugungair intake
- 66
- Schwingungsdämpfervibration damper
- 77
- Brenngaseintrittfuel gas inlet
- 88th
- Mischelementmixing element
- 99
- Lüfter /Gebläsefan/blower
- 1010
- Verbrennungsraumcombustion chamber
- 1111
- Abgaswegexhaust path
- 1212
- Abgasaustrittexhaust gas outlet
- 1313
- Abgasrückführungexhaust gas recirculation
- 1414
- Stelleinrichtungadjusting device
- 1515
- Auswerteelektronikevaluation electronics
- 1616
- Steuer- und Regeleinheitcontrol and regulation unit
- 1717
- Erster SensorFirst sensor
- 1818
- Referenzsensorreference sensor
- 1919
- Zweiter SensorSecond sensor
- 2020
- Einmündung AbgasrückführungJunction exhaust gas recirculation
- 2121
- Verbrennungsluftwegcombustion air path
- 2222
- Gas-Luft-Verbundgas-air compound
- AA
- erstes Signal mit einer typischen Signaturfirst signal with a typical signature
- BB
- zweites Signalsecond signal
- CC
- kreuzkorreliertes Signalcross-correlated signal
- Ff
- Feuchtehumidity
- Fexfex
- exzessive Feuchteexcessive moisture
- Fufoot
- Umgebungsfeuchte (Toleranzintervall)Ambient humidity (tolerance interval)
- FmaxFmax
- maximal mögliche Feuchtemaximum possible humidity
- KK
- Kreuzkorrelatorcross correlator
- LL
- Lokalisierungsintervalllocalization interval
- M1M1
- erste Differenz zwischen erstem Minimum und erstem Maximumfirst difference between first minimum and first maximum
- M2M2
- zweite Differenz zwischen erstem Maximum und zweitem Minimumsecond difference between first maximum and second minimum
- RR
- Rezirkulation von Abgasrecirculation of exhaust gas
- RmaxRmax
- maximal zulässige Rezirkulationmaximum allowable recirculation
- RnormRnorm
- normale Rezirkulationnormal recirculation
- SS
- zeitlicher Versatz (Shift) zwischen den Signalentime offset (shift) between the signals
- tt
- Zeittime
- TT
- Testverlauftest history
- VV
- Start Vorlauf des GebläsesStart advance of the fan
- ZZ
- Zündzeitpunktignition timing
Claims (12)
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DE102021102700.4A DE102021102700A1 (en) | 2021-02-05 | 2021-02-05 | Method and arrangement for using combustion products or properties of the air in the combustion air path of a gas-fired heating device for its control and/or status analysis |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6039560A (en) * | 1996-01-31 | 2000-03-21 | Sanyo Electric Co., Ltd. | Low NOx burner and method of controlling recirculation of exhaust gas |
US6095792A (en) * | 1998-08-21 | 2000-08-01 | Texaco Inc. | Flue gas recirculation system and method |
DE10302487A1 (en) * | 2002-01-25 | 2003-07-31 | Alstom Switzerland Ltd | Real time determination of the alkane and carbon dioxide content of fuel gas comprises using an infrared absorption measuring system having measuring channels which acquire the infrared adsorption in different wavelength regions |
US20120034568A1 (en) * | 2010-08-06 | 2012-02-09 | Honeywell International, Inc. | Combustion air control |
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DE19906285C2 (en) | 1999-02-15 | 2001-09-27 | Eberspaecher J Gmbh & Co | Fuel-operated heater for motor vehicles |
TW201502356A (en) | 2013-02-21 | 2015-01-16 | Exxonmobil Upstream Res Co | Reducing oxygen in a gas turbine exhaust |
DE202019100263U1 (en) | 2019-01-17 | 2019-02-04 | Ebm-Papst Landshut Gmbh | Heater with control of a gas mixture using a gas sensor, a fuel gas sensor and a gas mixture sensor |
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- 2021-02-05 DE DE102021102700.4A patent/DE102021102700A1/en active Pending
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- 2022-01-17 EP EP22151795.6A patent/EP4043792A1/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6039560A (en) * | 1996-01-31 | 2000-03-21 | Sanyo Electric Co., Ltd. | Low NOx burner and method of controlling recirculation of exhaust gas |
US6095792A (en) * | 1998-08-21 | 2000-08-01 | Texaco Inc. | Flue gas recirculation system and method |
DE10302487A1 (en) * | 2002-01-25 | 2003-07-31 | Alstom Switzerland Ltd | Real time determination of the alkane and carbon dioxide content of fuel gas comprises using an infrared absorption measuring system having measuring channels which acquire the infrared adsorption in different wavelength regions |
US20120034568A1 (en) * | 2010-08-06 | 2012-02-09 | Honeywell International, Inc. | Combustion air control |
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