EP3596391B1 - Method for controlling a combustion-gas operated heating device - Google Patents

Method for controlling a combustion-gas operated heating device Download PDF

Info

Publication number
EP3596391B1
EP3596391B1 EP18758556.7A EP18758556A EP3596391B1 EP 3596391 B1 EP3596391 B1 EP 3596391B1 EP 18758556 A EP18758556 A EP 18758556A EP 3596391 B1 EP3596391 B1 EP 3596391B1
Authority
EP
European Patent Office
Prior art keywords
ionization
gas
air
volume flow
mixture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP18758556.7A
Other languages
German (de)
French (fr)
Other versions
EP3596391A1 (en
Inventor
Enno Jan Vrolijk
Jan Dannemann
Hartmut Hennrich
Jens Hermann
Hans-Joachim Klink
Stephan Wald
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ebm Papst Landshut GmbH
Original Assignee
Ebm Papst Landshut GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ebm Papst Landshut GmbH filed Critical Ebm Papst Landshut GmbH
Publication of EP3596391A1 publication Critical patent/EP3596391A1/en
Application granted granted Critical
Publication of EP3596391B1 publication Critical patent/EP3596391B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N1/00—Regulating fuel supply
    • F23N1/02—Regulating fuel supply conjointly with air supply
    • F23N1/022—Regulating fuel supply conjointly with air supply using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
    • F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L5/00—Blast-producing apparatus before the fire
    • F23L5/02—Arrangements of fans or blowers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2223/00—Signal processing; Details thereof
    • F23N2223/06—Sampling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2227/00—Ignition or checking
    • F23N2227/20—Calibrating devices

Definitions

  • the invention relates to a method for regulating a fuel gas-operated heater.
  • Another problem with the control method is that different types of gas, e.g. Natural gas or liquid gas, as well as gas qualities, are used.
  • the parameters of the control process must be adapted to the type of gas or gas quality, as otherwise the combustion will be unclean.
  • the air ratio is preferably different for different burner power points and for different gas families (eg natural gas or liquid gas). This relationship is usually stored in the control unit in the form of performance-dependent ⁇ characteristics. Automatic gas type detection is required to automatically select the correct characteristic.
  • the calorific value of the different gases corresponds approximately to the value of the air requirement L. This relationship is used to precontrol the modulating combustion air fan to a desired burner output. Since all gases change their volume under different temperatures and pressures, the conditions listed above only apply under the same pressure and temperature conditions. In the case of the different conditions for gas and air in practice, however, either the respective mass flow or correspondingly corrected volume flows must be used as a basis for regulating the combustion process (exa temperature increase of 30 K, air expands by 10% without more air molecules participating in the combustion process so that without correction the air ratio would decrease by 10%).
  • the invention is based on the object of providing a gas type-independent method for regulating a fuel gas-operated heating device.
  • the method should be able to determine the type of gas and its control parameters to be adaptable to the specific type of gas in further developments.
  • a method for regulating a fuel gas-operated heater using an ionization setpoint power characteristic wherein a gas volume flow supplied via a gas supply and an air volume flow supplied via a fan are mixed to form a gas-air mixture and with an air ratio ⁇ based on a desired burner output Burner of the heater are fed.
  • the air ratio ⁇ is monitored by means of an ionization measurement method of a burner flame of the burner.
  • the mixture calibration is carried out by an ionization current control, in which the air ratio ⁇ of the gas-air mixture is adjusted to a value ⁇ ion-max at which a maximum ionization measurement signal is achieved on an ionization electrode of the ionization measurement in the burner flame. From the maximum ionization measurement signal, an ionization signal target value for the air ratio ⁇ is calculated at a calibration point and then the air ratio ⁇ ion-max is adjusted to a target air ratio ⁇ soll until the ionization measurement signal corresponds to the calculated ionization signal target value.
  • the burner output is regulated for the respective heat demand on the heater.
  • the amount of air required for this is changed by a control unit with the speed-controlled fan.
  • the fan speed essentially corresponds to the air volume flow.
  • the supplied gas volume flow is varied by an electrically modulated gas actuator or gas valve and measured by a gas mass flow sensor.
  • the gas volume flow is also regulated via the control unit.
  • the fan is preferably designed as a premix fan for mixing gas and air, so that the fan supplies a mixture volume flow to the burner.
  • the gas-air mixture control is based on the continuous detection of the air volume flow by a fan speed detection and the downstream regulation of the gas volume via the control unit, the target value of the gas volume being taken from a stored characteristic curve.
  • the plausibility check can determine whether the parameters influencing optimal combustion such as gas type, gas quality, exhaust system, components of the heater such as the non-return valves in front of the burner or the heat exchanger function in the desired way. Any change in these parameters affects the gas / air ratio and therefore the ionization measurement signal. This in turn can be detected.
  • the parameters influencing optimal combustion such as gas type, gas quality, exhaust system, components of the heater such as the non-return valves in front of the burner or the heat exchanger function in the desired way. Any change in these parameters affects the gas / air ratio and therefore the ionization measurement signal. This in turn can be detected.
  • the mixture calibration according to the invention enables the air ratio ⁇ to be adjusted and the heater to be converted into optimal combustion, taking into account the parameters influencing the combustion.
  • the values of the air requirement value L are known for each gas, as described above.
  • the gas type determination can thus be recorded automatically via the mixture calibration and stored in the control unit of the heater.
  • the control device can then use laboratory-technically predefined control characteristics for the corresponding type of gas, in particular the corresponding ionization setpoint power characteristic, for further control.
  • an advantageous embodiment of the method provides for the ionization setpoint power characteristic to be adapted by the mixture calibration over an entire power range of the heater if the ionization measurement signal is above a specified threshold value from an ionization measurement signal. Setpoint deviates. The adaptation of the ionization setpoint power characteristic takes place over its entire course by the ratio detected at the calibration point of the mixture calibration. The new ionization setpoint power characteristic is then saved. After the mixture calibration, the gas and air quantities are regulated along the stored characteristic curve with the corresponding performance-dependent air ratio and the newly determined air requirement value L.
  • the air ratio ⁇ is adjusted by changing the gas volume flow or gas mass flow until the ionization measurement signal corresponds to the calculated ionization signal setpoint. This is possible in a simple and very precise way by activating the gas actuator. The actual gas mass flow can also be compared directly via the gas mass flow sensor.
  • the mixture calibration can be run through in a long version and in a short version.
  • a mixture volume flow is first generated at a defined fan speed and the associated air volume flow is recorded.
  • a maximum value of the ionization signal is determined immediately, and from this a new ionization target value for a known one is determined and adjusted.
  • the air requirement is determined from the gas and air volume regulated at this operating point and used for further mixture control.
  • the associated ionization signal setpoint is determined via the ionization setpoint power characteristic.
  • the ionization current signal is measured by the control unit and compared with the currently stored characteristic curve value.
  • the steps of the ionization current regulation are then run through and the ionization target value power characteristic curve is adapted and stored as described above. In this case, the ionization signal maximum only has to be determined in exceptional cases.
  • the mixture calibration is preferably carried out at a power point of the heater which corresponds to its maximum power or the burner power in a range of 50-70%.
  • the method includes a transit time measurement to check the correct function of the gas mass sensor.
  • a transit time measurement an amount of the supplied gas volume flow is actively varied via a control of the gas actuator or gas valve and the transit time between the control and the detection of the gas volume variation at the gas mass sensor is compared with a predefined setpoint transit time.
  • the gas valve position can be increased or reduced by a pulse, an oscillation or an actual value jump when it is varied.
  • the nominal run time is determined in advance in the laboratory. If the running time is above a limit value, there is a gas sensor fault and the heater is set to emergency mode, for example with limited modulation.
  • the method also includes a run time measurement to determine the gas-air mixture volume flow.
  • the amount of the supplied gas volume flow is actively varied and the transit time between the activation and a change in the ionization measurement signal and, optionally, additionally the level and type of change in the ionization measurement signal is recorded.
  • the measured transit time is then with compared to a laboratory-based predetermined transit time-volume flow characteristic. If the effect on the ionization measurement signal due to the change in gas volume flow is too small or if the ionization measurement signal changes in the wrong direction, the heater is switched to emergency mode. If the effect is within the tolerance range, the mixture volume flow is determined from the comparison of the running time using a table of values determined by the laboratory.
  • the transit time measurement is repeated at predetermined time intervals.
  • a plausibility check of a sufficient air volume flow is continuously implemented over the entire performance range.
  • the blower speed is checked for plausibility in terms of safety.
  • the runtime measurement can be used as a further expansion stage in order to carry out a combustion air calculation according to the stationary recorded values at various power points. This means that the internally stored characteristic curve for calculating the combustion air can be corrected dynamically.
  • the method also provides that the actual air volume flow is calculated from a difference between the set air volume flow and the mixture volume flow determined via the transit time measurement and optionally a measured temperature of the air volume flow.
  • the method provides that the fan speed and a target air volume flow resulting therefrom are continuously compared with the actual air volume flow. If the speed deviates too much in the course of operation despite the same air volume flow, for example due to a blocked heat exchanger, the control unit switches off the heater and issues an alarm message.
  • the method includes the integration of the mixture calibration in a starting method for cold starting the heater. Ignition attempts of the gas-air mixture are carried out until a burner flame is detected via the ionization measurement.
  • the gas mass flow present at the time of ignition is kept constant and stored in the control unit.
  • the starting air requirement L start is determined from the ratio of the gas volume flow to the air volume flow taken from the blower characteristic and corresponding to the ignition speed, and the gas type is determined from this as described above.
  • the starting point for the next burner start is determined from the stored gas mass flow and the ignition range.
  • FIG 1 is a schematic structure of a heater 100 for carrying out the control method with a modulating premix blower 5, the ambient air a and mixes with gas.
  • the gas is fed to the premix blower 5 via a gas line in which a gas safety valve 1, a gas valve 2 controllable by way of example via a motor M and a gas mass sensor 3 are arranged.
  • the gas inlet pressure d is adapted to the gas control pressure c.
  • the mixture After mixing with ambient air, the mixture has the mixture pressure b.
  • an optional non-return flap 6 is provided at the blower outlet.
  • the mixture then has the burner pressure e. This is followed by the burner 28 with the ionization electrode 7 arranged in the burner flame and a siphon 10 connected to the burner housing.
  • the heat exchanger 18 is arranged around the burner 28. Continued in the flow direction, the exhaust system follows with the exhaust flap 8. The exhaust gas pressure f prevails in the exhaust system. The amount of gas and the fan speed and therefore the air ratio are regulated by means of the control unit 9, in which the regulating characteristics are stored.
  • FIG. 2 shows the partial process of the mixture calibration of the control procedure in the short version.
  • the fan speed n of the premix fan 5 is set to a fixed value via the control device 9 and the actual air volume flow vL-ist is calculated in step 300 using the run time measurement described above.
  • the ionization flow control takes place at a fixed air volume flow vL-act, in that the gas quantity is increased until a maximum ionization measurement signal (lo-max) is reached.
  • the ionization signal setpoint (lo-soll, lo-neu) for the desired air ratio ⁇ is calculated from the maximum ionization measurement signal and the gas quantity is then regulated in step 615 until the ionization measurement signal corresponds to the calculated ionization signal setpoint lo-soll.
  • the short version of the ionization calibration takes place with every mixture calibration.
  • FIG. 3 shows the partial process of the mixture calibration of the control method in the long version.
  • the fan speed n of the premix fan 5 is set to a fixed value via the control device 9 and the actual air volume flow vL-ist is calculated.
  • the ionization signal setpoint value lo-soll is determined using the ionization setpoint power characteristic and the burner power P.
  • the ionization current at the ionization electrode 7 is measured by the control unit 9 in an ionization measurement process and compared with the characteristic value. If the values match, the measured ionization current is used for further mixture calibration.
  • the ionization setpoint performance characteristic is calibrated by increasing the gas quantity in step 612 with a fixed air volume flow vL-act until a maximum ionization measurement signal lo-max is reached. From the maximum ionization measurement signal, the ionization signal setpoint 624 (lo-soll) for the desired air ratio ⁇ (at 625) is calculated. According to step 613, the original ionization setpoint power characteristic curve lo-old is corrected over its entire power range by the ratio detected at the calibration point of the mixture calibration to the new ionization setpoint power characteristic curve lo-new. The new ionization target value performance characteristic lo-new is stored in the memory of the control device 9.
  • step 615 the amount of gas is regulated until the ionization measurement signal corresponds to the calculated target ionization signal value lo-soll.
  • ionization calibration is only carried out in exceptional cases.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Regulation And Control Of Combustion (AREA)

Description

Die Erfindung betrifft ein Verfahren zur Regelung eines brenngasbetriebenen Heizgerätes.The invention relates to a method for regulating a fuel gas-operated heater.

Gattungsbildende Verfahren sind aus dem Stand der Technik bekannt, beispielsweise aus der Offenbarung gemäß der Druckschrift WO2006/000366A1 . Auch kennt der Fachmann eine Verbrennungsregelung nach dem sog. SCOT-Verfahren, bei dem die Steuerung der dem Brenner des Heizgerätes zugeführte Luftmenge entsprechend der Brennerleistung erfolgt. Dabei wird eine Flammensignalmessung mittels eines lonisationssensors durchgeführt und das Gas-Luftgemisch auf einen in einer Kennlinie hinterlegten Soll-lonisationsmesswert geregelt. Beim SCOT-Verfahren ist jedoch nachteilig, dass bei kleinen Brennerleistungen das Flammensignal stark absinkt und die Regelung damit unzuverlässig wird. Zudem ist der Adaptionsaufwand, insbesondere zur Anpassung der Brennergeometrie hoch und die Brennerleistung kann nur ungenau über die Gebläsedrehzahl eines den Luftvolumenstrom für das Gas-Luft-Gemisch liefernden Gebläses bestimmt werden.Generic methods are known from the prior art, for example from the disclosure according to the publication WO2006 / 000366A1 . The person skilled in the art is also familiar with combustion control according to the so-called SCOT method, in which the amount of air supplied to the burner of the heater is controlled according to the burner output. A flame signal measurement is carried out by means of an ionization sensor and the gas-air mixture is based on a characteristic curve stored nominal ionization measurement value regulated. The disadvantage of the SCOT process, however, is that the flame signal drops sharply at low burner outputs, making the control unreliable. In addition, the adaptation effort, in particular for adapting the burner geometry, is high and the burner output can only be determined imprecisely via the fan speed of a fan supplying the air volume flow for the gas-air mixture.

Eine Problematik der Regelungsverfahren liegt zudem darin, dass für die Verbrennung unterschiedliche Gasarten, z.B. Erdgas oder Flüssiggas, sowie Gasqualitäten zum Einsatz kommen. Die Parameter des Regelungsverfahrens müssen auf die Gasart bzw. Gasqualität angepasst werden, da die Verbrennung andernfalls unsauber abläuft.Another problem with the control method is that different types of gas, e.g. Natural gas or liquid gas, as well as gas qualities, are used. The parameters of the control process must be adapted to the type of gas or gas quality, as otherwise the combustion will be unclean.

Für Regelungsverfahren der vorliegenden Art gilt, dass die Luftzahl λ in der Technik das Verhältnis zwischen Luft und Gas bestimmt, wobei beispielsweise eine Luftzahl λ=1,3 einem Luftüberschuss von 30% entspricht. Ein für ein bestimmtes Gas erforderlicher Luftbedarf L ist abhängig von der Gasbeschaffenheit, wobei beispielhafte Werte für Propan: L= ca. 30, Erdgas aus der Gruppe H: L= ca. 10 und Erdgas aus der Gruppe L: L= ca. 8 sind. Die Luftzahl ist in der Praxis vorzugsweise bei verschiedenen Brennerleistungspunkten und bei verschiedenen Gasfamilien (z.B. Erdgas oder Flüssiggas) unterschiedlich. In der Regel wird dieser Zusammenhang in Form von leistungsabhängigen λ-Kennlinien im Steuergerät abgespeichert. Zur automatischen Auswahl der richtigen Kennlinie ist eine automatische Gasarterkennung nötig. Der zu einem definierten Gas-Luftgemisch erforderliche Luftvolumenstrom vL berechnet sich aus dem Gasvolumenstrom vG multipliziert mit dem Luftbedarf L multipliziert mit der Luftzahl: vL= vG ∗ L ∗ A.For control methods of the present type, the air ratio λ in technology determines the ratio between air and gas, with an air ratio λ = 1.3 for example corresponding to an air excess of 30%. An air requirement L required for a certain gas depends on the gas quality, with exemplary values for propane: L = approx. 30, natural gas from group H: L = approx. 10 and natural gas from group L: L = approx. 8 . In practice, the air ratio is preferably different for different burner power points and for different gas families (eg natural gas or liquid gas). This relationship is usually stored in the control unit in the form of performance-dependent λ characteristics. Automatic gas type detection is required to automatically select the correct characteristic. The air volume flow vL required for a defined gas-air mixture is calculated from the gas volume flow vG multiplied by the air requirement L multiplied by the air ratio: vL = vG ∗ L ∗ A.

Der Brennwert der unterschiedlichen Gase entspricht näherungsweise dem Wert des Luftbedarfes L. Dieser Zusammenhang wird zur Vorsteuerung des modulierenden Verbrennungsluftgebläses auf eine gewünschte Brennerleistung genutzt. Da alle Gase unter unterschiedlichen Temperaturen und Drücken ihr Volumen verändern, gelten die oben aufgeführten Bedingungen nur bei gleichen Druck- und Temperaturbedingungen. Bei den in der Praxis jedoch abweichenden Bedingungen für Gas und Luft muss zur Regelung des Verbrennungsprozess entweder der jeweilige Massenstrom oder entsprechend korrigierte Volumenströme zugrunde gelegt werden (Beispiel: bei 30 K Temperaturerhöhung dehnt sich Luft um 10% aus, ohne dass mehr Luftmoleküle am Verbrennungsprozess beteiligt wären, so dass ohne Korrektur die Luftzahl um 10% sinken würde).The calorific value of the different gases corresponds approximately to the value of the air requirement L. This relationship is used to precontrol the modulating combustion air fan to a desired burner output. Since all gases change their volume under different temperatures and pressures, the conditions listed above only apply under the same pressure and temperature conditions. In the case of the different conditions for gas and air in practice, however, either the respective mass flow or correspondingly corrected volume flows must be used as a basis for regulating the combustion process (example: at a temperature increase of 30 K, air expands by 10% without more air molecules participating in the combustion process so that without correction the air ratio would decrease by 10%).

Der Erfindung liegt die Aufgabe zugrunde, ein gasartenunabhängiges Verfahren zur Regelung eines brenngasbetriebenen Heizgerätes bereitzustellen. Zudem soll in Weiterbildungen mit dem Verfahren die Gasart bestimmbar und seine Regelungsparameter an die bestimmte Gasart anpassbar sein.The invention is based on the object of providing a gas type-independent method for regulating a fuel gas-operated heating device. In addition, the method should be able to determine the type of gas and its control parameters to be adaptable to the specific type of gas in further developments.

Diese Aufgabe wird durch die Merkmalskombination gemäß Patentanspruch 1 gelöst.This object is achieved by the combination of features according to patent claim 1.

Erfindungsgemäß wird ein Verfahren zur Regelung eines brenngasbetriebenen Heizgerätes unter Nutzung einer lonisations-Sollwert-Leistungskennlinie vorgeschlagen, wobei ein über eine Gaszuführung gelieferter Gasvolumenstrom und ein über ein Gebläse gelieferter Luftvolumenstrom zu einem Gas-Luftgemisch gemischt und mit einer auf einer gewünschten Brennerleistung basierenden Luftzahl λ einem Brenner des Heizgerätes zugeführt werden. Die Luftzahl λ wird mittels einem lonisationsmessverfahren einer Brennerflamme des Brenners überwacht. Zudem wird eine Plausibilitätskontrolle durchgeführt, bei der ein lonisationsmesssignal des lonisationsmessverfahrens ausgewertet wird, und im Falle einer Abweichung von einem lonisationsmesssignal-Sollwert eine Gemischkalibration des Gas-Luftgemisches erfolgt. Die Gemischkalibration erfolgt durch eine lonisationsstromregelung, bei der die Luftzahl λ des Gas-Luftgemisches auf einen Wert λion-max angepasst wird, bei dem ein maximales lonisationsmesssignal an einer lonisationselektrode der lonisationsmessung in der Brennerflamme erreicht ist. Aus dem maximalen lonisationsmesssignal wird ein lonisationssignalsollwert für die Luftzahl λ in einem Kalibrierungspunkt errechnet und anschließend die Luftzahl λion-max auf eine Soll-Luftzahl λsoll angepasst, bis das lonisationsmesssignal dem errechneten lonisationssignalsollwert entspricht.According to the invention, a method for regulating a fuel gas-operated heater using an ionization setpoint power characteristic is proposed, wherein a gas volume flow supplied via a gas supply and an air volume flow supplied via a fan are mixed to form a gas-air mixture and with an air ratio λ based on a desired burner output Burner of the heater are fed. The air ratio λ is monitored by means of an ionization measurement method of a burner flame of the burner. There is also a plausibility check carried out, in which an ionization measurement signal of the ionization measurement method is evaluated, and in the event of a deviation from an ionization measurement signal target value, a mixture calibration of the gas-air mixture takes place. The mixture calibration is carried out by an ionization current control, in which the air ratio λ of the gas-air mixture is adjusted to a value λ ion-max at which a maximum ionization measurement signal is achieved on an ionization electrode of the ionization measurement in the burner flame. From the maximum ionization measurement signal, an ionization signal target value for the air ratio λ is calculated at a calibration point and then the air ratio λ ion-max is adjusted to a target air ratio λ soll until the ionization measurement signal corresponds to the calculated ionization signal target value.

Grundsätzlich erfolgt die Regelung der Brennerleistung der jeweiligen Wärmebedarfsanforderung an das Heizgerät. Die dazu erforderliche Luftmenge wird mit dem drehzahlgeregeltem Gebläse von einem Steuergerät verändert. Die Gebläsedrehzahl entspricht im Wesentlichen dem Luftvolumenstrom. Der zugeführte Gasvolumenstrom wird durch ein elektrisch moduliertes Gasstellglied bzw. Gasventil variiert und durch einen Gasmassenstromsensor gemessen. Die Regelung des Gasvolumenstroms erfolgt ebenfalls über das Steuergerät. Das Gebläse ist vorzugsweise als Vormischgebläse zur Mischung von Gas und Luft ausgebildet, so dass das Gebläse einen Gemischvolumenstrom an den Brenner liefert. Die Gas-Luftgemischregelung beruht auf der kontinuierlichen Erfassung des Luftvolumenstroms durch eine Gebläsedrehzahlerfassung und der nachgeschalteten Ausregelung der Gasmenge über das Steuergerät, wobei der Sollwert der Gasmenge aus einer gespeicherten Kennlinie entnommen wird.Basically, the burner output is regulated for the respective heat demand on the heater. The amount of air required for this is changed by a control unit with the speed-controlled fan. The fan speed essentially corresponds to the air volume flow. The supplied gas volume flow is varied by an electrically modulated gas actuator or gas valve and measured by a gas mass flow sensor. The gas volume flow is also regulated via the control unit. The fan is preferably designed as a premix fan for mixing gas and air, so that the fan supplies a mixture volume flow to the burner. The gas-air mixture control is based on the continuous detection of the air volume flow by a fan speed detection and the downstream regulation of the gas volume via the control unit, the target value of the gas volume being taken from a stored characteristic curve.

Über die Plausibilitätskontrolle kann mit dem erfindungsgemäßen Verfahren festgestellt werden, ob die eine optimale Verbrennung beeinflussenden Parameter wie Gasart, Gasqualität, Abgassystem, Baugruppen des Heizgerätes wie die Rückschlagklappen vor dem Brenner oder der Wärmetauscher in der gewünschten Art und Weise funktionieren. Jede Änderung dieser Parameter beeinflusst das Gas-Luftverhältnis und mithin das lonisationsmesssignal. Dies wiederum kann detektiert werden.Using the method according to the invention, the plausibility check can determine whether the parameters influencing optimal combustion such as gas type, gas quality, exhaust system, components of the heater such as the non-return valves in front of the burner or the heat exchanger function in the desired way. Any change in these parameters affects the gas / air ratio and therefore the ionization measurement signal. This in turn can be detected.

Die erfindungsgemäße Gemischkalibration ermöglicht die Anpassung der Luftzahl λ und die Überführung des Heizgeräts in die optimale Verbrennung unter Berücksichtigung der die Verbrennung beeinflussenden Parametern.The mixture calibration according to the invention enables the air ratio λ to be adjusted and the heater to be converted into optimal combustion, taking into account the parameters influencing the combustion.

Vorteilhafterweise kann mit dem Verfahren aus der Soll-Luftzahl λsoll ein Luftbedarfswert L errechnet und über den Luftbedarfswert L die Gasart bestimmt werden, denn aus der Formel vL= vG∗L∗λ folgt, dass L=vL/(vG∗λ). Die Werte des Luftbedarfswerts L sind wie oben beschrieben für jedes Gas bekannt. Die Gasartbestimmung kann somit automatisch über die Gemischkalibration erfasst und im Steuergerät des Heizgerätes hinterlegt werden. Zudem kann das Steuergerät anschließend labortechnisch vordefinierte Regelungskennlinien für die entsprechende Gasart, insbesondere die entsprechende lonisations-Sollwert-Leistungskennlinie, zur weiteren Regelung verwenden.Advantageously, the method can be used to calculate an air requirement value L from the target air ratio λ should and the gas type can be determined using the air requirement value L, because the formula vL = vG ∗ L ∗ λ implies that L = vL / (vG ∗ λ). The values of the air requirement value L are known for each gas, as described above. The gas type determination can thus be recorded automatically via the mixture calibration and stored in the control unit of the heater. In addition, the control device can then use laboratory-technically predefined control characteristics for the corresponding type of gas, in particular the corresponding ionization setpoint power characteristic, for further control.

Da die Regelung des Heizgerätes entlang der lonisations-Sollwert-Leistungskennlinie erfolgt, sieht eine vorteilhafte Ausführung des Verfahrens vor, die lonisations-Sollwert-Leistungskennlinie durch die Gemischkalibration über einen gesamten Leistungsbereich des Heizgerätes anzupassen, wenn das lonisationsmesssignal oberhalb eines festgelegten Schwellenwerts von einem lonisationsmesssignal-Sollwert abweicht. Die Anpassung der lonisations-Sollwert-Leistungskennlinie erfolgt dabei über ihren gesamten Verlauf um das bei dem Kalibrierungspunkt der Gemischkalibration erfasste Verhältnis. Die neue lonisations-Sollwert-Leistungskennlinie wird anschließend gespeichert. Nach der Gemischkalibration werden die Gas- und Luftmenge entlang der gespeicherten Kennlinie mit der entsprechend leistungsabhängigen Luftzahl und dem neu festgelegten Luftbedarfswert L geregelt.Since the control of the heater takes place along the ionization setpoint power characteristic, an advantageous embodiment of the method provides for the ionization setpoint power characteristic to be adapted by the mixture calibration over an entire power range of the heater if the ionization measurement signal is above a specified threshold value from an ionization measurement signal. Setpoint deviates. The adaptation of the ionization setpoint power characteristic takes place over its entire course by the ratio detected at the calibration point of the mixture calibration. The new ionization setpoint power characteristic is then saved. After the mixture calibration, the gas and air quantities are regulated along the stored characteristic curve with the corresponding performance-dependent air ratio and the newly determined air requirement value L.

Bei der lonisationsstromregelung der Gemischkalibration wird die Luftzahl λ durch Veränderung des Gasvolumenstromes oder Gasmassenstromes angepasst, bis das lonisationsmesssignal dem errechneten lonisationssignalsollwert entspricht. Dies ist über die Ansteuerung des Gasstellglieds auf einfach und sehr exakte Weise möglich. Über den Gasmassenstromsensor kann zudem unmittelbar der tatsächliche Gasmassenstrom abgeglichen werden.In the case of the ionization flow regulation of the mixture calibration, the air ratio λ is adjusted by changing the gas volume flow or gas mass flow until the ionization measurement signal corresponds to the calculated ionization signal setpoint. This is possible in a simple and very precise way by activating the gas actuator. The actual gas mass flow can also be compared directly via the gas mass flow sensor.

Die Gemischkalibration kann in einer Langversion und in einer Kurzversion durchlaufen werden. In beiden Varianten wird zunächst ein Gemischvolumenstrom bei einer festgelegten Gebläsedrehzahl erzeugt und der zugehörige Luftvolumenstrom erfasst. Bei der Kurzversion wird unmittelbar ein Maximalwert des lonisationssignales ermittelt und daraus ein neuer lonisations-sollwert für ein bekanntes ermittelt und eingeregelt. Aus der in diesem Arbeitspunkt eingeregelten Gas- und Luftmenge wird der Luftbedarf bestimmt und für die weitere Gemischregelung genutzt.The mixture calibration can be run through in a long version and in a short version. In both variants, a mixture volume flow is first generated at a defined fan speed and the associated air volume flow is recorded. In the short version, a maximum value of the ionization signal is determined immediately, and from this a new ionization target value for a known one is determined and adjusted. The air requirement is determined from the gas and air volume regulated at this operating point and used for further mixture control.

In der Langversion wird im Anschluss an die Erfassung des Luftvolumenstroms über die lonisations-Sollwert-Leistungskennlinie der zugehörige lonisationssignalsollwert ermittelt. Das lonisationsstromsignal wird vom Steuergerät gemessen und mit dem aktuell hinterlegten Kennlinienwert verglichen. Anschließend werden die Schritte der lonisationsstromregelung durchlaufen und die lonisations-Sollwert-Leistungskennlinie wie vorstehend beschrieben angepasst und gespeichert. In diesem Fall muss nur in Ausnahmefällen das lonisationssignalmaximum ermittelt werden.In the long version, following the acquisition of the air volume flow, the associated ionization signal setpoint is determined via the ionization setpoint power characteristic. The ionization current signal is measured by the control unit and compared with the currently stored characteristic curve value. The steps of the ionization current regulation are then run through and the ionization target value power characteristic curve is adapted and stored as described above. In this case, the ionization signal maximum only has to be determined in exceptional cases.

Die Gemischkalibration erfolgt vorzugsweise bei einem Leistungspunkt des Heizgerätes, der in einem Bereich von 50-70% seiner Maximalleistung bzw. der Brennerleistung entspricht.The mixture calibration is preferably carried out at a power point of the heater which corresponds to its maximum power or the burner power in a range of 50-70%.

Grundsätzlich wird bei dem vorliegenden Regelungsverfahren zur Festlegung des über das Gebläse gelieferten Luftvolumenstroms für die erforderliche bzw. angeforderte Brennerleistung aus einer Luftzahl-Leistungskennlinie die gewünschte Luftzahl ermittelt und daraus der über das Gebläse zu liefernde Luftvolumenstrom über die Formel vL=P∗λ berechnet.In the present control method to determine the air volume flow supplied by the fan for the required or requested burner output, the desired air ratio is determined from an air ratio performance characteristic and from this the air volume flow to be supplied by the fan is calculated using the formula vL = P ∗ λ.

In einer Weiterbildung des Verfahrens ist vorgesehen, dass es eine Laufzeitmessung zur Prüfung der richtigen Funktion des Gasmassensensors umfasst. Bei der Laufzeitmessung wird eine Menge des zugeführten Gasvolumenstroms über eine Ansteuerung des Gasstellglieds bzw. Gasventils aktiv variiert und die Laufzeit zwischen der Ansteuerung und der Erfassung der Gasvolumenvariation an dem Gasmassensensor mit einem vordefinierten Laufzeit-Sollwert verglichen. Die Gasventilstellung kann bei der Variation um einen Impuls, eine Schwingung oder einen Istwertsprung erhöht oder reduziert werden. Der Laufzeit-Sollwert wird vorab labortechnisch ermittelt. Liegt die Laufzeit oberhalb eines Grenzwertes, liegt eine Gassensorstörung vor und das Heizgerät wird in einen Notbetrieb, beispielsweise mit beschränkter Modulation gesetzt.In a further development of the method it is provided that it includes a transit time measurement to check the correct function of the gas mass sensor. In the transit time measurement, an amount of the supplied gas volume flow is actively varied via a control of the gas actuator or gas valve and the transit time between the control and the detection of the gas volume variation at the gas mass sensor is compared with a predefined setpoint transit time. The gas valve position can be increased or reduced by a pulse, an oscillation or an actual value jump when it is varied. The nominal run time is determined in advance in the laboratory. If the running time is above a limit value, there is a gas sensor fault and the heater is set to emergency mode, for example with limited modulation.

Zudem umfasst das Verfahren in einer Ausführungsvariante eine Laufzeitmessung zur Bestimmung des Gas-Luft-Gemischvolumenstromes. Dabei wird die Menge des zugeführten Gasvolumenstroms aktiv variiert und die Laufzeit zwischen der Ansteuerung und einer Änderung des lonisationsmesssignals und optional zusätzlich der Höhe und Art der Änderung des lonisationsmesssignals erfasst. Die gemessene Laufzeit wird anschließend mit einer labortechnisch vorbestimmten Laufzeit-Volumenstrom-Kennlinie verglichen. Ist die Auswirkung auf das lonisationsmesssignal aufgrund der Gasvolumenstromänderung zu gering oder verändert sich das lonisationsmesssignal in die falsche Richtung, wird das Heizgerät in den Notbetrieb gefahren. Liegt die Auswirkung im Toleranzbereich, wird aus dem Laufzeitvergleich über eine labortechnisch ermittelte Wertetabelle der Gemischvolumenstrom bestimmt.In one embodiment variant, the method also includes a run time measurement to determine the gas-air mixture volume flow. The amount of the supplied gas volume flow is actively varied and the transit time between the activation and a change in the ionization measurement signal and, optionally, additionally the level and type of change in the ionization measurement signal is recorded. The measured transit time is then with compared to a laboratory-based predetermined transit time-volume flow characteristic. If the effect on the ionization measurement signal due to the change in gas volume flow is too small or if the ionization measurement signal changes in the wrong direction, the heater is switched to emergency mode. If the effect is within the tolerance range, the mixture volume flow is determined from the comparison of the running time using a table of values determined by the laboratory.

Zudem ist vorteilhaft, dass die Laufzeitmessung in vorbestimmten Zeitabständen wiederholt wird. Dadurch wird stetig über den gesamten Leistungsbereich eine Plausibilisierung eines hinreichenden Luftvolumenstromes umgesetzt. Somit wird die Gebläsedrehzahl sicherheitstechnisch plausibilisiert. Als weitere Ausbaustufe kann die Laufzeitmessung herangezogen werden, um eine Verbrennungsluftberechnung gemäß den stationär erfassten Werten an verschiedenen Leistungspunkten durchzuführen. Dadurch kann die intern gespeicherte Kennlinie zur Verbrennungsluftberechnung dynamisch korrigiert werden.It is also advantageous that the transit time measurement is repeated at predetermined time intervals. As a result, a plausibility check of a sufficient air volume flow is continuously implemented over the entire performance range. In this way, the blower speed is checked for plausibility in terms of safety. The runtime measurement can be used as a further expansion stage in order to carry out a combustion air calculation according to the stationary recorded values at various power points. This means that the internally stored characteristic curve for calculating the combustion air can be corrected dynamically.

Das Verfahren sieht ferner vor, dass der tatsächliche Luftvolumenstrom aus einer Differenz des eingestellten Luftvolumenstroms und dem über die Laufzeitmessung bestimmten Gemischvolumenstroms und optional einer gemessene Temperatur des Luftvolumenstroms berechnet wird.The method also provides that the actual air volume flow is calculated from a difference between the set air volume flow and the mixture volume flow determined via the transit time measurement and optionally a measured temperature of the air volume flow.

Als weiteres Merkmal sieht das Verfahren vor, dass die Gebläsedrehzahl und ein sich draus ergebender Soll-Luftvolumenstrom kontinuierlich mit dem tatsächlichen Luftvolumenstrom abgeglichen werden. Bei einer zu großen Abweichung der Drehzahl im Laufe des Betriebs trotz gleichen Luftvolumenstromes, beispielsweise durch einen verstopften Wärmetauscher, schaltet das Steuergerät das Heizgerät ab und gibt eine Alarmmeldung aus.As a further feature, the method provides that the fan speed and a target air volume flow resulting therefrom are continuously compared with the actual air volume flow. If the speed deviates too much in the course of operation despite the same air volume flow, for example due to a blocked heat exchanger, the control unit switches off the heater and issues an alarm message.

Als weiterer Aspekt umfasst das Verfahren die Integration der Gemischkalibration in ein Startverfahren zum Kaltstart des Heizgerätes. Dabei werden Zündversuche des Gas-Luftgemisches durchgeführt, bis über die lonisationsmessung eine Brennerflamme detektiert wird. Der zum Zündzeitpunkt vorliegende Gasmassenstrom wird konstant gehalten und im Steuergerät abgespeichert. Aus dem Verhältnis aus Gasvolumenstrom zu dem aus der Gebläsekennlie entnommenen und der Zünd-Drehzahl entsprechenden Luftvolumenstrom wird der Start-Luftbedarf Lstart ermittelt und daraus wie vorstehend beschrieben die Gasart bestimmt. Aus dem abgespeicherten Gasmassenstrom und dem Zündbereich wird der Startpunkt für den nächsten Brennerstart festgelegt.As a further aspect, the method includes the integration of the mixture calibration in a starting method for cold starting the heater. Ignition attempts of the gas-air mixture are carried out until a burner flame is detected via the ionization measurement. The gas mass flow present at the time of ignition is kept constant and stored in the control unit. The starting air requirement L start is determined from the ratio of the gas volume flow to the air volume flow taken from the blower characteristic and corresponding to the ignition speed, and the gas type is determined from this as described above. The starting point for the next burner start is determined from the stored gas mass flow and the ignition range.

Soweit vorliegend auf "Volumenstrom" abgestellt wird, kann in gleicher Weise auch der Massenstrom angewendet werden.If the focus is on "volume flow", the mass flow can also be used in the same way.

Andere vorteilhafte Weiterbildungen der Erfindung sind in den Unteransprüchen gekennzeichnet bzw. werden nachstehend zusammen mit der Beschreibung der bevorzugten Ausführung der Erfindung anhand der Figuren näher dargestellt. Es zeigen:

Fig. 1
einen schematischen Aufbau eines Heizgerätes;
Fig. 2
einen Ablauf der Gemischkalibration in der Kurzversion,
Fig. 3
einen Ablauf der Gemischkalibration in der Langversion.
Other advantageous developments of the invention are characterized in the subclaims or are shown in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. Show it:
Fig. 1
a schematic structure of a heater;
Fig. 2
a sequence of the mixture calibration in the short version,
Fig. 3
a sequence of mixture calibration in the long version.

In Figur 1 ist ein schematischer Aufbau eines Heizgerätes 100 zur Durchführung des Regelungsverfahrens mit einem modulierenden Vormischgebläse 5, das Umgebungsluft a ansaugt und mit Gas mischt. Das Gas wird dem Vormischgebläse 5 über eine Gasleitung zugeführt, in der ein Gassicherheitsventil 1, ein beispielhaft über einen Motor M steuerbares Gasventil 2 sowie ein Gasmassensensor 3 angeordnet sind. Der Gaseingangsdruck d wird auf den Gasregeldruck c angepasst. Nach der Mischung mit Umgebungsluft weist das Gemisch den Gemischdruck b auf. Am Gebläseausgang ist in der gezeigten Ausführung eine optionale Rückschlagklappe 6 vorgesehen. Das Gemisch hat dann den Brennerdruck e. Daran schließt sich der Brenner 28 mit der in der Brennerflamme angeordneten lonisationselektrode 7 und einem mit dem Brennergehäuse verbundenen Siphon 10 an. Um den Brenner 28 ist der Wärmetauscher 18 angeordnet. In Strömungsrichtung fortgesetzt folgt das Abgassystem mit der Abgasklappe 8. Im Abgassystem herrscht der Abgasdruck f. Die Regelung der Gasmenge sowie der Gebläsedrehzahl und mithin der Luftzahl erfolgt über das Steuergerät 9, in dem die Regelungskennlinien hinterlegt sind.In Figure 1 is a schematic structure of a heater 100 for carrying out the control method with a modulating premix blower 5, the ambient air a and mixes with gas. The gas is fed to the premix blower 5 via a gas line in which a gas safety valve 1, a gas valve 2 controllable by way of example via a motor M and a gas mass sensor 3 are arranged. The gas inlet pressure d is adapted to the gas control pressure c. After mixing with ambient air, the mixture has the mixture pressure b. In the embodiment shown, an optional non-return flap 6 is provided at the blower outlet. The mixture then has the burner pressure e. This is followed by the burner 28 with the ionization electrode 7 arranged in the burner flame and a siphon 10 connected to the burner housing. The heat exchanger 18 is arranged around the burner 28. Continued in the flow direction, the exhaust system follows with the exhaust flap 8. The exhaust gas pressure f prevails in the exhaust system. The amount of gas and the fan speed and therefore the air ratio are regulated by means of the control unit 9, in which the regulating characteristics are stored.

Figur 2 zeigt den Teilprozess der Gemischkalibration des Regelungsverfahrens in der Kurzversion. Zunächst wird in dem Schritt 601 die Gebläsedrehzahl n des Vormischgebläses 5 über das Steuergerät 9 auf einen festen Wert eingesteuert und mittels der vorstehend beschriebenen Laufzeitmessung im Schritt 300 der tatsächliche Luftvolumenstrom vL-ist berechnet. Anschließend erfolgt unter Schritt 612 die lonisationsstromregelung bei einem festgelegtem Luftvolumenstrom vL-ist, indem die Gasmenge soweit erhöht wird, bis ein maximales lonisationsmesssignal (lo-max) erreicht ist. Aus dem maximalen lonisationsmesssignal wird der lonisationssignalsollwert (lo-soll, lo-neu) für die gewünschte Luftzahl λ errechnet und anschließend im Schritt 615 die Gasmenge soweit geregelt, bis das lonisationsmesssignal dem errechneten lonisationssignalsollwert lo-soll entspricht. Der sich im neuen Betriebspunkt ergebende Gasmassenstrom Gas-ist wird verwendet, um im Schritt 617 unter Nutzung der Luftzahl-Leistungskennlinie und mithin der Luftzahl λsoll, dem Luftvolumenstrom vL und der aktuellen Brennerleistung den Luftbedarfswert L=vL/(vG∗λsoll) zu errechnen und über den Luftbedarfswert L die Gasart zu bestimmen. Die lonisationskalibrierung in der Kurzversion erfolgt bei jeder Gemischkalibration. Figure 2 shows the partial process of the mixture calibration of the control procedure in the short version. First, in step 601 the fan speed n of the premix fan 5 is set to a fixed value via the control device 9 and the actual air volume flow vL-ist is calculated in step 300 using the run time measurement described above. Then, in step 612, the ionization flow control takes place at a fixed air volume flow vL-act, in that the gas quantity is increased until a maximum ionization measurement signal (lo-max) is reached. The ionization signal setpoint (lo-soll, lo-neu) for the desired air ratio λ is calculated from the maximum ionization measurement signal and the gas quantity is then regulated in step 615 until the ionization measurement signal corresponds to the calculated ionization signal setpoint lo-soll. The resulting gas mass flow gas actual at the new operating point is used in step 617 using the air ratio performance characteristic and thus the air ratio λ soll , dem Air volume flow vL and the current burner output to calculate the air requirement value L = vL / (vG ∗ λ soll ) and to determine the gas type via the air requirement value L. The short version of the ionization calibration takes place with every mixture calibration.

Figur 3 zeigt den Teilprozess der Gemischkalibration des Regelungsverfahrens in der Langversion. Zunächst wird in den Schritten 601 und 300 die Gebläsedrehzahl n des Vormischgebläses 5 über das Steuergerät 9 auf einen festen Wert eingesteuert und der tatsächliche Luftvolumenstrom vL-ist berechnet. Anschließend erfolgt unter Schritt 605 die Ermittlung des lonisationssignalsollwerts lo-soll unter Nutzung der lonisations-Sollwert-Leistungskennlinie und der Brennerleistung P. Gemäß Schritt 607 wird in einem lonisationsmessverfahren der lonisationsstrom an der lonisationselektrode 7 durch das Steuergerät 9 gemessen und mit dem Kennlinienwert verglichen. Bei einer Übereinstimmung der Werte wird der gemessene lonisationsstrom zur weiteren Gemischkalibration verwendet. Ist die Abweichung der Vergleichswerte größer als ein vorab definierter Schwellenwert, erfolgt eine Kalibration der lonisations-Sollwert-Leistungskennlinie, indem unter Schritt 612 bei festgelegtem Luftvolumenstrom vL-ist die Gasmenge soweit erhöht wird, bis ein maximales lonisationsmesssignal lo-max erreicht ist. Aus dem maximalen lonisationsmesssignal wird der lonisationssignalsollwert 624 (lo-soll) für die gewünschte Luftzahl λ (bei 625) errechnet. Gemäß Schritt 613 wird die ursprüngliche lonisations-Sollwert-Leistungskennlinie lo-alt über ihren gesamten Leistungsbereich um das bei dem Kalibrierungspunkt der Gemischkalibration erfasste Verhältnis auf die neue lonisations-Sollwert-Leistungskennlinie lo-neu korrigiert. Die neue lonisations-Sollwert-Leistungskennlinie lo-neu wird im Speicher des Steuergerätes 9 hinterlegt. In Schritt 615 wird die Gasmenge soweit geregelt, bis das lonisationsmesssignal dem errechneten lonisationssignalsollwert lo-soll entspricht. Der sich im neuen Betriebspunkt ergebende Gasmassenstrom Gas-ist wird verwendet, um im Schritt 617 unter Nutzung der Soll-Luftzahl λsoll der Luftbedarfswert L=vL/(vG∗λsoll) zu errechnen und über den Luftbedarfswert L die Gasart zu bestimmen. Bei der Langversion erfolgt eine lonisationskalibrierung nur in Ausnahmefällen. Figure 3 shows the partial process of the mixture calibration of the control method in the long version. First, in steps 601 and 300, the fan speed n of the premix fan 5 is set to a fixed value via the control device 9 and the actual air volume flow vL-ist is calculated. Then, in step 605, the ionization signal setpoint value lo-soll is determined using the ionization setpoint power characteristic and the burner power P. According to step 607, the ionization current at the ionization electrode 7 is measured by the control unit 9 in an ionization measurement process and compared with the characteristic value. If the values match, the measured ionization current is used for further mixture calibration. If the deviation of the comparison values is greater than a previously defined threshold value, the ionization setpoint performance characteristic is calibrated by increasing the gas quantity in step 612 with a fixed air volume flow vL-act until a maximum ionization measurement signal lo-max is reached. From the maximum ionization measurement signal, the ionization signal setpoint 624 (lo-soll) for the desired air ratio λ (at 625) is calculated. According to step 613, the original ionization setpoint power characteristic curve lo-old is corrected over its entire power range by the ratio detected at the calibration point of the mixture calibration to the new ionization setpoint power characteristic curve lo-new. The new ionization target value performance characteristic lo-new is stored in the memory of the control device 9. In step 615, the amount of gas is regulated until the ionization measurement signal corresponds to the calculated target ionization signal value lo-soll. The resulting in the new operating point gas mass flow gas is used to (intended PG * λ) using the target excess air factor λ to the air requirement value L = vL / in step 617 to calculate and determine the type of gas across the air demand value L. With the long version, ionization calibration is only carried out in exceptional cases.

Claims (13)

  1. A method for regulating a fuel-gas-operated heating device (100) using an ionization target value-output characteristic curve, wherein the regulation of the heating device (100) takes place along the ionization target value-output characteristic curve and in this case
    a. a gas volume flow supplied via a gas supply and an air volume flow supplied via a fan are mixed to form a gas-air mixture and are supplied to a burner (28) of the heating device with an air-fuel ratio λ based on a desired burner output,
    b. the air-fuel ratio A is monitored by means of an ionization measuring method of a burner flame of the burner (28),
    c. a plausibility check is performed in which an ionization measurement signal of the ionization measuring method is evaluated, and in the case of a deviation from an ionization measurement signal target value, a mixture calibration of the gas-air mixture takes place, and wherein
    d. the mixture calibration is carried out by an ionization current regulation, in which the gas-air mixture is adapted to a value at which a maximum ionization measurement signal is achieved, and an ionization signal target value for the target air-fuel ratio λtarget at a calibration point is calculated from the maximum ionization measurement signal, wherein in the ionization current regulation, the mixture calibration of the air-fuel ratio A is adapted by changing the gas volume flow or gas mass flow until the ionization measurement signal corresponds to the calculated ionization signal target value.
  2. The method as claimed in claim 1, characterized in that an air requirement value L is calculated from the target air-fuel ratio λtargat and a gas type of the gas is determined via the air requirement value.
  3. The method as claimed in claim 1 or 2, characterized in that, in the mixture calibration, the air-fuel ratio A is adapted by changing the gas volume flow until the ionization measurement signal corresponds to the calculated ionization signal target value.
  4. The method as claimed in any one of the preceding claims, characterized in that the regulation of the heating device (100) takes place along the ionization target value-output characteristic curve and the ionization target value-characteristic curve is adapted by the mixture calibration over an entire output range of the heating device if the ionization measurement signal deviates from an ionization measurement signal target value above a defined threshold value.
  5. The method as claimed in any one of the preceding claims, characterized in that, in the mixture calibration, firstly a volume flow is produced and measured at a fixed fan speed, and the associated ionization signal target value is ascertained via the ionization target value-output characteristic curve.
  6. The method as claimed in any one of the preceding claims, characterized in that, to establish the air volume flow supplied via the fan for a required burner output, the desired air-fuel ratio is ascertained from an air-fuel ratio-output characteristic curve and the air volume flow to be supplied via the fan is calculated therefrom.
  7. The method as claimed in any one of the preceding claims, characterized in that it comprises a runtime measurement for checking a gas mass sensor, in which a quantity of the supplied gas volume flow is actively varied via an activation of a gas valve (2) and a runtime between the activation and a detection of the gas volume variation at the gas mass sensor (3) is compared to a predefined runtime target value.
  8. The method as claimed in any one of the preceding claims, characterized in that it comprises a runtime measurement for determining the gas-air mixture volume flow, in which a quantity of the supplied gas volume flow is actively varied via an activation of a gas valve (2) and a runtime between the activation and a change of the ionization measurement signal and optionally additionally a level and type of the change of the ionization measurement signal are detected, and wherein the measured runtime is compared to a runtime-volume flow characteristic curve predetermined in a laboratory and the mixture volume flow is determined therefrom.
  9. The method as claimed in any one of the preceding claims, characterized in that the actual volume flow is calculated from a difference of a set air value flow and the mixture volume flow determined via the runtime measurement and optionally a measured temperature of the air volume flow.
  10. The method as claimed in any one of preceding claims 8-9, characterized in that the runtime measurement is repeated at predetermined time intervals,
  11. The method as claimed in any one of preceding claims 9-10, characterized in that a fan speed of the fan (5) and a target air volume flow resulting therefrom are continuously compared to the actual air volume flow.
  12. The method as claimed in any one of the preceding claims, characterized in that the mixture calibration is performed at an output point of the heating device which corresponds to a range of 50-70% of its maximum output.
  13. The method as claimed in any one of the preceding claims, characterized in that the mixture calibration is integrated into a starting method for the cold start of the heating device.
EP18758556.7A 2017-11-08 2018-08-09 Method for controlling a combustion-gas operated heating device Active EP3596391B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102017126137.0A DE102017126137A1 (en) 2017-11-08 2017-11-08 Method for controlling a fuel gas operated heater
PCT/EP2018/071669 WO2019091612A1 (en) 2017-11-08 2018-08-09 Method for controlling a combustion-gas operated heating device

Publications (2)

Publication Number Publication Date
EP3596391A1 EP3596391A1 (en) 2020-01-22
EP3596391B1 true EP3596391B1 (en) 2020-12-30

Family

ID=63294200

Family Applications (1)

Application Number Title Priority Date Filing Date
EP18758556.7A Active EP3596391B1 (en) 2017-11-08 2018-08-09 Method for controlling a combustion-gas operated heating device

Country Status (4)

Country Link
EP (1) EP3596391B1 (en)
CN (1) CN110573800B (en)
DE (1) DE102017126137A1 (en)
WO (1) WO2019091612A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018105185A1 (en) 2018-03-07 2019-09-12 Ebm-Papst Landshut Gmbh Method for detecting fuel gas in a fuel gas operated heater
DE102019003451A1 (en) * 2019-05-16 2020-11-19 Truma Gerätetechnik GmbH & Co. KG Method for monitoring a burner and / or a burning behavior of a burner and burner arrangement
DE102020102117A1 (en) 2020-01-29 2021-07-29 Ebm-Papst Landshut Gmbh Method for optimizing a tolerance range of a control characteristic of an electronic mixture control in a gas heater
EP3913285A1 (en) * 2020-05-22 2021-11-24 Pittway Sarl Method and controller for operating a gas burner appliance
CN114576648B (en) * 2021-11-18 2022-12-06 浙江菲斯曼供热技术有限公司 Method for operating a gas burner

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE59604283D1 (en) * 1995-10-25 2000-03-02 Stiebel Eltron Gmbh & Co Kg Method and circuit for regulating a gas burner
DE102004055716C5 (en) 2004-06-23 2010-02-11 Ebm-Papst Landshut Gmbh Method for controlling a firing device and firing device (electronic composite I)
DE102010008908B4 (en) * 2010-02-23 2018-12-20 Robert Bosch Gmbh A method of operating a burner and the air-frequency controlled modulating a burner power
DE102010046954B4 (en) * 2010-09-29 2012-04-12 Robert Bosch Gmbh Method for calibration, validation and adjustment of a lambda probe
DE102010055567B4 (en) * 2010-12-21 2012-08-02 Robert Bosch Gmbh Method for stabilizing a performance of a gas-fired burner
CN103256623B (en) * 2012-02-20 2015-06-17 宝山钢铁股份有限公司 Method for flexibly controlling air excess coefficient of impulse burner
DE102014224891A1 (en) * 2014-12-04 2016-06-09 Robert Bosch Gmbh A heater apparatus and method of operating a heater apparatus
DE102015116458A1 (en) * 2015-09-29 2017-03-30 Viessmann Werke Gmbh & Co Kg Method for distinguishing between two combustion gases provided for a combustion process with different levels of energy

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Also Published As

Publication number Publication date
DE102017126137A1 (en) 2019-05-09
CN110573800A (en) 2019-12-13
WO2019091612A1 (en) 2019-05-16
CN110573800B (en) 2021-06-15
EP3596391A1 (en) 2020-01-22

Similar Documents

Publication Publication Date Title
EP3596391B1 (en) Method for controlling a combustion-gas operated heating device
EP2594848B1 (en) Method for controlling a firing device and firing device
EP3683500B1 (en) Method for regulating a gas mixture using a gas sensor and a gas mixture sensor
EP3824366B1 (en) Method for the closed-loop control of a gas mixture using a gas sensor, a combustion-gas sensor and a gas-mixture sensor
DE202019100263U1 (en) Heater with control of a gas mixture using a gas sensor, a fuel gas sensor and a gas mixture sensor
EP1717514B1 (en) Gas burner and methods for starting and operating the same
EP3499124A1 (en) Heating device components and method for adjusting a fuel flow
EP3182007B1 (en) Heating device system and method with a heating device system
EP3680553B1 (en) Method for regulating the combustion air ratio of a burner of a heater
EP3746705A1 (en) Method for controlling a gas mixture using a gas mixture sensor
DE102015207672B3 (en) Method for controlling a fuel delivery system
EP1923634B1 (en) Adjustment of fuel gas/air mixture via the burner or flame temperature of a heating device
DE102013220954A1 (en) Heater with a burner assisted by a fan
EP3751200B1 (en) Method for controlling a heater powered by combustion gas
EP2615278A2 (en) Metering device with a gas mixer and method for controlling gas mixture formation
EP3707433A1 (en) Method for controlling a combustion-gas operated heating device
WO2020030323A1 (en) Method for controlling a mixing ratio of fuel gas and air for a heating appliance
DE102011111453A1 (en) Method for adjusting air ratio of combustion air-fuel mixture to desired air speed in air-fuel mixture combustion, involves controlling air ratio, when variation of combustion air flow or fuel quantity is less than or equal to variation
AT505064B1 (en) REGULATION OF THE FUEL GAS AIR MIXTURE ON THE BURNER OR FLAME TEMPERATURE OF A HEATER
DE10220774B4 (en) Burner control device
EP3859210B1 (en) Method for optimizing a tolerance range of a control characteristic of an electronic mixture control in a gas heater
DE202019100264U1 (en) Heater with control of a gas mixture using a gas sensor and a gas mixture sensor
EP1351019B1 (en) Process to check the operation of the regulation system of heating burner
DE102004063992B4 (en) Regulating and controlling process for firing apparatus involves using characteristic curve showing value range for setpoint temperature in accordance with two parameters
DE202004017851U1 (en) Firing equipment for gas burners has means for determining value dependent on measured temperature and means for regulating generated temperature using characteristic line representing value range corresponding to ideal temperature

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20191015

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

RIN1 Information on inventor provided before grant (corrected)

Inventor name: HENNRICH, HARTMUT

Inventor name: DANNEMANN, JAN

Inventor name: VROLIJK, ENNO JAN

Inventor name: KLINK, HANS-JOACHIM

Inventor name: WALD, STEPHAN

Inventor name: HERMANN, JENS

RIN1 Information on inventor provided before grant (corrected)

Inventor name: HERMANN, JENS

Inventor name: HENNRICH, HARTMUT

Inventor name: VROLIJK, ENNO JAN

Inventor name: WALD, STEPHAN

Inventor name: DANNEMANN, JAN

Inventor name: KLINK, HANS-JOACHIM

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
INTG Intention to grant announced

Effective date: 20200930

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 502018003511

Country of ref document: DE

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 1350308

Country of ref document: AT

Kind code of ref document: T

Effective date: 20210115

REG Reference to a national code

Ref country code: NL

Ref legal event code: FP

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: GERMAN

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210330

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210330

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG9D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210430

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210430

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502018003511

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

26N No opposition filed

Effective date: 20211001

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

REG Reference to a national code

Ref country code: BE

Ref legal event code: MM

Effective date: 20210831

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20210831

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20210831

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210430

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20210809

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20210809

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20210831

P01 Opt-out of the competence of the unified patent court (upc) registered

Effective date: 20230521

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SM

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20180809

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: TR

Payment date: 20230802

Year of fee payment: 6

Ref country code: IT

Payment date: 20230831

Year of fee payment: 6

Ref country code: GB

Payment date: 20230824

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20230821

Year of fee payment: 6

Ref country code: DE

Payment date: 20230822

Year of fee payment: 6

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20240821

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20201230