EP4174374B1 - Method for starting a heating device, computer program , and heating device - Google Patents

Description

The invention relates to methods for commissioning a heating device, a computer program product, a control device and a heating device.

To start up heating devices, a mixture of fuel gas and combustion air is often fed into a burner and ignited. It has been shown that, particularly in heating devices with a pneumatic gas-air connection, the composition of the gas mixture for ignition can fluctuate due to the system. The fluctuations are due, among other things, to tolerances and the dynamic characteristics of the gas valve, fluctuations in the calorific value of the gas to be burned and/or the characteristics, in particular the flow resistance, of the exhaust system of the heating device.

This means that if the proportion of fuel gas is too high, ignition can be accompanied by a lot of noise. If the proportion of fuel gas is too low, the gas mixture may not be ignitable and/or several ignition processes may be necessary for commissioning. Both consequences are unpleasant for the user and also place increased strain on the heater. They can also lead to a service technician having to carry out maintenance work, which entails corresponding costs.

In the DE 41 42 841 A1 In order to reduce pollutant emissions during the start-up process of a heater, it is proposed to promote the ignition process with the full combustion air flow provided at operating temperature and, if necessary, to carry out a new ignition process with a reduced combustion air flow if no flame is formed. However, the proposed method increases the risk of a hard ignition with the associated risk of damage to the heater.

The EP 3 054 216 A1 describes a control method for a switch-on function sequence for a fuel-operated heater. It is proposed that when switching on, the same amount of fuel but a smaller air mass should be supplied during a transition phase, thus reducing the air/fuel ratio lambda during a defined period of time, which can last up to 20 seconds, compared to the ratio in the steady state. In this way, the components involved in mixture formation, combustion and heat transfer can be heated more quickly, and the emissions of certain exhaust gas components can be reduced in the transition phase. However, this method cannot be used for commissioning a heater with a pneumatic gas-air system, since the amount of gas supplied is linked to the amount of air flowing in there. In addition, lowering the fuel/air ratio in the start-up phase could lead to an unsafe operating state, for example hard ignition, if the tolerances and dynamic characteristics of the gas valve are unfavorable.

The DE 15 01 894 A1 The subject of the invention is a method for regulating the air quantity of automatically operating gas burners, by means of which the air quantity is adapted to the purging and ignition process as well as to the normal operation of the burner. It is proposed that when the gas burner is started, it should initially be operated at maximum power and then reduce its output to an ignition output in order to increase the output of the fan to nominal output again after ignition. This method is also unable to avoid the problems mentioned, namely the effects of tolerances and dynamic characteristics of the gas valve on the combustion air ratio.

The EP 3 301 365 A1 also describes a method for controlling an ignition operation of a heating system, in which at least one operating characteristic value recorded before the ignition operation is taken into account. This is suitable for determining a quality of the fuel used and/or a power requirement. It is also proposed that a starting power of the heating system be selected close to a power requirement. However, the method is not suitable for including or reducing effects of a dynamic characteristic of the gas valve on the set combustion air ratio.

Influencing or regulating the composition of the combustion mixture is particularly difficult in a pneumatic (combustion) gas-air system because this is caused by the interaction of mechanical components. There are known ways of influencing this, for example a device for limiting the gas flow and/or a buffer storage unit. However, it has been found that the use of these can, under certain conditions, exacerbate the problems mentioned above in certain situations during the start-up process. In addition, the options mentioned are associated with costs. Another disadvantage is that the complexity of a heater equipped with them increases.

Based on this, it is the object of the invention to propose a method for commissioning a gas heating device with a pneumatic gas-air connection, which at least partially overcomes the problems of the state of the art described above. In particular, a safe and reliable start-up process should be guaranteed in almost all scenarios and operating situations that occur.

In addition, the proposed method should be easy to implement and at least not significantly increase the complexity of a heating device.

These objects are achieved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It is pointed out that the features listed in the dependent patent claims can be combined with one another in any technologically reasonable manner and define further embodiments of the invention. In addition, the features specified in the patent claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

The method proposed here is particularly suitable for gas heaters with a pneumatic gas-air connection. In such heaters, the combination of combustion air and combustion gas is essentially based on mechanical principles. Combustion gas is often added to an air flow conveyed by a conveyor using a Venturi nozzle. The gas flow supplied is therefore a delayed image of the air flow generated by the conveyor. The disadvantage of this purely mechanical combination of combustion gas and combustion air is that it can only be adjusted or controlled to a very limited extent.

The composition of the combustion mixture has a reference composition suitable for the starting process. A composition that has a lower proportion of fuel gas than the reference value is referred to as lean. Ignition of a lean combustion mixture is difficult, although high ignition performance can be advantageous. A composition that has a higher proportion of fuel gas than the reference value is referred to as rich.

The composition of the combustion mixture has a reference composition suitable for the ignition process. A composition that has a lower proportion of combustion gas than the reference value is referred to as lean. Ignition of a lean combustion mixture is difficult, although high ignition performance can be advantageous. A composition that has a higher proportion of combustion gas than the reference value is referred to as rich.

The composition of the combustion mixture can also be specified by a combustion air ratio λ, which indicates the ratio of the air mass actually available for combustion to the air mass required for complete combustion. A combustion air ratio of (significantly) over 1 thus indicates a lean mixture in which more combustion air is available than is required for the combustion of the existing combustion gas and, accordingly, a combustion air ratio of less than 1 indicates a rich combustion mixture in which insufficient combustion air is available for complete combustion.

The invention is based on the idea that the mixture composition can be influenced by means of a control of the conveyor device. When commissioning a heating device, the output of a conveyor device is usually increased as linearly as possible with the greatest possible gradient up to a reference output, whereby the flow rate of the combustion air at the reference power reaches a reference flow rate. Shortly before or in the area of reaching the reference flow rate, the gas valve opens and adds combustion gas to the fluid flow of the combustion air, for example through the Venturi effect. Due to its characteristics, a gas peak often occurs when the gas valve is opened, i.e. an area of the fluid flow of the combustion mixture which contains a significantly higher proportion of combustion gas than in the resulting operating state. According to the invention, this gas peak (also referred to as gas peak) can be used advantageously for an ignition process, for example when the composition of the combustion mixture is lean. In other situations, for example when the composition of the combustion mixture is rich, the gas peak can have a detrimental effect on an ignition process and should be reduced or dampened.

By specifically influencing the fluid flow conveyed by the conveying device, a rich mixture composition (i.e. a mixture composition with a high proportion of combustion gas) can be leaned out for the ignition point, and a leaner mixture composition (i.e. a mixture composition with a low proportion of combustion gas) can be enriched.

It has been shown that the extent of a gas peak when a gas valve is opened can be influenced by the flow rate of the combustion air, among other things. For example, opening the gas valve at a flow rate significantly below the reference flow rate can lead to a reduction in the gas peak and thus be suitable for igniting rich compositions of the combustion mixture. In contrast, with a lean composition of the combustion mixture, the gas peak can be a welcome increase in the proportion of combustion gas in the combustion mixture for an ignition process.

1. a) Steigern der Leistung der Fördereinrichtung bis zu einer (vorgebbaren ersten) Leistung mit einem (definierten, insbesondere konstanten, ersten) Anstieg,
2. b) Öffnen des Gasventils nach Erreichen der (vorgebbaren ersten) Leistung und Einleiten eines Zündvorganges beim Brenner,
3. c) für einen (vorgegebenen, ersten) Zeitraum (weitestgehendes) konstant halten der (vorgebbaren ersten) Leistung,
4. d) Ansteuern einer (von der vorgebbaren ersten Leistung abweichenden, vorgebbaren zweiten) Leistung der Fördereinrichtung mit einem (definierten, insbesondere konstanten, zweiten) Anstieg.

The method for commissioning a gas heater with a pneumatic gas-air connection comprises that the heater is operated with a start profile during commissioning and the start profile is adapted to the dynamic behavior of the mixture composition and to the formation of a gas peak during an ignition process, wherein the start profile comprises a power curve of a conveyor device of the heater and an opening time of a gas valve, wherein the power curve of a start profile comprises the following processes:

1. a) Increasing the performance of the conveyor up to a (specifiable first) performance with a (defined, in particular constant, first) increase,
2. b) Opening the gas valve after reaching the (predetermined first) power and initiating an ignition process at the burner,
3. c) keeping the (specifiable first) performance (as far as possible) constant for a (specified, first) period of time,
4. d) Controlling a (definable second) output of the conveyor system (which differs from the predefinable first output) with a (defined, in particular constant, second) increase.

A start profile within the meaning of this document can be a defined procedure or a definition of several different variable start parameters for commissioning components of the heater, with the aim of enabling a problem-free start-up of the heater. The parameters coordinated within the framework of the start profile can include, for example, a performance curve of a conveyor device for the combustion gas mixture or the combustion air, an ignition time of the burner, an ignition intensity and/or an instruction for operating a pneumatic restriction. The start profile determines in particular a temporal progression of a (possibly variable) setting of a parameter as well as an action and/or a temporal progression of a (possibly variable) setting of at least one other parameter. The start profile can include a (pre-defined selected) rigid, possibly time-fixed sequence of the two variable start parameters for commissioning the heater, for example for a specifically determined situation (fuel, fault messages, initial/recommissioning, etc.). Alternatively or cumulatively, it is also possible that the setting of the two variable start parameters is regulated during commissioning within the framework of the start profile using current parameters (in particular those determined during operation). It goes without saying that a start profile should also be tailored to the specific properties of the heater or heating system. In this context, particular mention should be made of the output of the heater, properties of the combustion chamber, properties of the exhaust system, in particular its length, and/or the specific fuel gas.

A performance curve of the conveying device can indicate a curve of a performance parameter of the conveying device as a function of the time with which the conveying device of the heating system is operated during commissioning. The performance parameter can be any parameter that characterizes the performance of the conveying device, for example a speed of a fan as a conveying device, a flow rate and/or a power consumption of the conveying device.

According to a preferred embodiment of the method, a start profile can be selected from at least two start profiles and the method can be carried out. If this method execution does not lead to a successful start, the method can then be carried out with a different start profile, etc. For this purpose, the start profiles can be stored with a prioritization, i.e. an indication of the order in which a method execution is attempted with these start profiles.

• e) (weitestgehend) konstant halten der (vorgebbaren zweiten) Leistung der Fördereinrichtung für einen (vorgegebenen, zweiten) Zeitraum,
• f) Ansteuern einer (von der vorgebbaren zweiten Leistung abweichenden, vorgebbaren dritten) Leistung mit einem (definierten, insbesondere konstanten, dritten) Anstieg.

According to a preferred embodiment, the method may additionally or subsequently comprise the following processes:

• e) keeping the (specifiable second) performance of the conveyor (as far as possible) constant for a (specified, second) period of time,
• f) Controlling a (definable third power that differs from the predefined second power) with a (defined, in particular constant, third) increase.

For the sake of clarity, it should be noted that the increases can take on both negative and positive values. "Increase" here refers in particular to a linear increase; the resulting change in performance can also be caused by any other function, for example an exponential function or a logarithmic function.

According to a preferred embodiment of the method, specific start profiles can be defined, for example, for lean and/or rich mixture compositions and/or for long exhaust systems. The start profiles do not have to be assigned to a specific purpose; a large number of different start profiles can also be stored, and the most suitable one can be determined as part of the processing of the various start profiles.

• Anfahren einer Fördereinrichtung des Heizgerätes mit hohem (ersten) Anstieg, also hoher Beschleunigung (eine hohe bzw. große Beschleunigung sollte gleichwohl ein möglichst präzises Ansteuern der avisierten (ersten oder zweiten) Leistung ermöglichen) bis zu einer (ersten) Leistung zwischen 20% und 40% der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht (mit anderen Worten, der Leistung mit der die Fördereinrichtung bei maximaler Leistung des Heizgerätes betrieben wird); häufig kann eine Leistung einer Fördereinrichtung, die einer maximalen Leistung eines Heizgerätes entspricht, im Bereich von 10.000 U/min [Umdrehungen pro Minute liegen].
• Öffnen des Gasventils,
• Start eines Zündvorganges mit normalen Einstellungen (gekennzeichnet beispielsweise durch eine durchschnittliche Zündenergie und/oder Zündfrequenz)
• Warten für einen (ersten) Zeitraum von ca. 0,1s bis 0,3s [Sekunden], zur Stabilisierung der Flamme, wobei die Leistung der Fördereinrichtung weitestgehend konstant bleibt,
• steigern der Leistung der Fördereinrichtung bis zu einer (zweiten) Leistung im Bereich zwischen 60% und 70% der der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht mit hohem (zweiten) Anstieg, der etwa bzw. exakt dem vorherigen (ersten) Anstieg entsprechen kann,
• mindern der Leistung der Fördereinrichtung auf eine (dritte) Leistung im Bereich von zwischen 20% und 40% der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht mit einem (dritten) Anstieg, dessen Betrag weitestgehend zwei Drittel vom zuerst gewählten (ersten) Anstieg entspricht.

For example, a start profile for a normal start or also for a rich mixture composition (it has been shown that a suitable start profile for a normal start is also suitable for a rich mixture composition in many heaters) can include a performance curve with at least the following features:

• Starting a conveyor of the heater with a high (first) rise, i.e. high acceleration (a high or large acceleration should nevertheless enable the intended (first or second) power to be controlled as precisely as possible) up to a (first) power between 20% and 40% of the conveyor power, which corresponds to the maximum power of the heater (in other words, the power with the the conveyor is operated at the maximum power of the heater); often a conveyor power corresponding to a maximum power of a heater can be in the range of 10,000 rpm [revolutions per minute].
• opening the gas valve,
• Start of an ignition process with normal settings (characterized, for example, by an average ignition energy and/or ignition frequency)
• Wait for a (first) period of approximately 0.1s to 0.3s [seconds] to stabilize the flame, while the performance of the conveyor remains largely constant,
• increasing the output of the conveyor up to a (second) output in the range between 60% and 70% of the output of the conveyor, which corresponds to the maximum output of the heater with a high (second) increase, which can correspond approximately or exactly to the previous (first) increase,
• reducing the output of the conveyor to a (third) output in the range of between 20% and 40% of the output of the conveyor corresponding to the maximum output of the heater with a (third) increase whose amount corresponds approximately to two thirds of the first selected (first) increase.

• Anfahren einer Fördereinrichtung des Heizgerätes mit hohem (ersten) Anstieg, also hoher Beschleunigung bis zu einer (ersten) Leistung im Bereich zwischen 30% und 60% der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht,
• Öffnen des Gasventils,
• Starten eines Zündvorganges mit Einstellungen für eine magere Gemischzusammensetzung (diese kann eine höhere Zündenergie und geringere Zündfrequenz als ein normaler Zündvorgang aufweisen).
• kein Warten, bzw. nur einen sehr kurzen (ersten) Zeitraum von maximal 0,1s [Sekunden] mit weitestgehend konstanter Leistung der Fördereinrichtung,
• Steigern der Leistung der Fördereinrichtung bis zu einer (zweiten) Leistung im Bereich zwischen 75% und 95% der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht, mit einem (zweiten) Anstieg, der weitestgehend zwei Dritteln des vorherigen (ersten) Anstieges entspricht.

For example, a starting profile for a lean mixture composition may include a power curve with at least the following features:

• Starting a conveyor of the heater with a high (first) rise, i.e. high acceleration up to a (first) power in the range between 30% and 60% of the conveyor power, which corresponds to the maximum power of the heater,
• opening the gas valve,
• Starting an ignition process with settings for a lean mixture composition (this can have a higher ignition energy and lower ignition frequency than a normal ignition process).
• no waiting, or only a very short (first) period of maximum 0.1s [seconds] with largely constant performance of the conveyor system,
• Increasing the output of the conveyor up to a (second) output in the range between 75% and 95% of the output of the conveyor corresponding to the maximum output of the heater, with a (second) increase corresponding as closely as possible to two thirds of the previous (first) increase.

• Anfahren einer Fördereinrichtung des Heizgerätes mit hohem (ersten) Anstieg, also hoher Beschleunigung bis zu einer (ersten) Leistung im Bereich zwischen 62% und 82% der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht,
• Öffnen des Gasventils,
• Starten eines Zündvorganges mit Einstellungen, die denen für eine magere Gemischzusammensetzung entsprechen,
• Warten für einen (ersten) Zeitraum von ca. 0,2s bis 0,4s [Sekunden], zur Stabilisierung der Flamme, wobei die Leistung der Fördereinrichtung weitestgehend konstant bleibt,
• mindern der Leistung der Fördereinrichtung bis zu einer (zweiten) Leistung im Bereich zwischen 54% und 74% der der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht mit sehr hohem Betrag des negativen (zweiten) Anstieges, beispielsweise erzielt durch eine Außerbetriebnahme der Fördereinrichtung,
• Warten für einen (zweiten) Zeitraum von ca. 2s bis 4s [Sekunden], wobei die Leistung der Fördereinrichtung weitestgehend konstant bleibt,
• Steigern der Leistung der Fördereinrichtung auf eine (dritte) Leistung im Bereich zwischen zwischen 62% und 82% der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht, mit einem (dritten) Anstieg, der ungefähr dem zuerst gewählten (ersten) Anstieg entspricht.

For example, a starting profile for a long exhaust system (for example from a length of approx. 8 meters, whereby the properties of the exhaust system, such as its volume, as well as the specific properties of the heater, for example the volume of the combustion chamber, can be included) can include a performance curve with at least the following features:

• Starting up a conveyor of the heater with a high (first) rise, i.e. high acceleration up to a (first) power in the range between 62% and 82% of the conveyor power, which corresponds to the maximum power of the heater,
• opening the gas valve,
• Starting an ignition process with settings corresponding to those for a lean mixture composition,
• Wait for a (first) period of approximately 0.2s to 0.4s [seconds] to stabilize the flame, while the performance of the conveyor remains largely constant,
• reducing the output of the conveyor down to a (second) output in the range between 54% and 74% of the output of the conveyor corresponding to the maximum output of the heater with a very high amount of negative (second) increase, for example achieved by decommissioning the conveyor,
• Waiting for a (second) period of approximately 2s to 4s [seconds], whereby the performance of the conveyor remains largely constant,
• Increasing the output of the conveyor to a (third) output in the range between 62% and 82% of the output of the conveyor corresponding to the maximum output of the heater, with a (third) increase approximately corresponding to the first selected (first) increase.

After a successful ignition process, the heater can go into normal operating mode after the start profile has been completed. Each of the above-mentioned start profiles is tailored to the dynamic behavior of the mixture composition, in particular the formation of a gas peak, during an ignition process and can reinforce or counteract the natural behavior of the mixture composition.

As a precaution, it should be noted that the start profiles described above are only examples. The design of the start profiles depends, among other things, on the specific heater, its performance data and exhaust system and the properties of the fuel used. When implementing the start profiles, steps can therefore be omitted or added in order to meet the specific requirements of the heater to be operated.

In a preferred embodiment of the method, the conveying device can be a blower. The performance curve of the conveying device can relate, among other things, to a speed of the blower.

According to a preferred embodiment of the method, after an unsuccessful start-up process, in particular after an unsuccessful ignition process, a new start-up process can be initiated with a different start-up profile. For example, different start-up profiles can be tried for different possible situations until a start-up profile is found that enables a successful start-up process.

According to a preferred method, an ignition control method can be carried out during a process run, which includes an evaluation of an ionization signal. An ionization signal from a flame enables a quick and direct conclusion to be drawn as to whether a flame is present, but also as to the quality and stability of the flame.

• ein Zeitraum zwischen Öffnung des Gasventils und dem ersten Auftreten des lonisationssignals,
• eine Anzahl des Auftretens des lonisationssignals während eines Zündvorganges,
• eine Stärke des lonisationssignals, und
• eine Intensität eines Rauschens des lonisationssignals.

According to a preferred embodiment of the method, at least one of the following features of the ionization signal is included:

• a period of time between opening the gas valve and the first occurrence of the ionization signal,
• a number of occurrences of the ionization signal during an ignition process,
• a strength of the ionization signal, and
• an intensity of a noise of the ionization signal.

As part of the ignition control procedure, a (current) performance of the conveying device, in particular a speed of a fan as a conveying device, can be included at the time of the ionization signal.

According to a preferred embodiment, an evaluation of the executed start profiles can be carried out as part of the ignition control method. This evaluation is preferably stored. The evaluation can relate in particular to various aspects that characterize the success of the ignition process for the respective start profile.

According to a further preferred embodiment, the stored evaluation can be used to select a start profile when the heater is subsequently put into operation. In this way, if the mixture composition is changed Due to the design features of the gas valve, it can be assumed that these do not change with every start-up process. This can be advantageously used to ensure that at least when the heater is started up, a start-up profile is used that allows for problem-free start-up. This can be advantageously used to shorten the duration of a start-up process by selecting a successful start-up profile right from the start.

According to a preferred embodiment, the at least one evaluation of a start profile can be deleted after a certain number of unsuccessful attempts. Preferably, the method can start up the heater with a standardized sequence of start profiles and then evaluate the start profiles again. For example, due to wear on the gas valve or a change in the composition and/or calorific value of the fuel, it may become apparent over a period of time that the highest-rated start profile no longer guarantees a successful ignition process. A new evaluation process can then be used to find the most suitable start profile at that time.

According to a preferred embodiment, after a defined number of unsuccessful attempts to start up the heater with different start profiles, the heater can switch to a fault mode. For example, the defined number of attempts can include trying each stored start profile twice.

According to a further aspect, a heating device with a pneumatic gas-air connection, at least one conveying device, a gas valve, and a regulating and control device is proposed, wherein the regulating and control device is set up to cause the heating device to carry out the steps of the method described here.

It is possible to carry out the method as a computer-implemented method, comprising steps a) to d). It is possible to provide a device or a system for data processing, comprising means for carrying out these steps of the method specified here.

According to another aspect, a computer program is also proposed which is set up to carry out a method presented here. In other words, this relates in particular to a computer program (product) comprising commands which, when the program is executed by a computer, cause the computer to carry out a method described here. According to a further aspect, a machine-readable storage medium is also proposed on which the computer program is stored. According to a preferred embodiment, at least one start profile defined according to the invention is stored on the memory. The machine-readable storage medium is usually a computer-readable data carrier.

According to a further aspect, a control device for a heating device is also proposed, designed to carry out a method presented here. The control device can for example have a processor or have one. In this context, the processor can for example carry out the method stored in a memory (of the control device). Preferably, At least one start profile defined using a method proposed here is stored in the memory. Particularly preferably, several start profiles are stored and an order of the stored start profiles.

According to a further aspect, a heating device with a control and regulation device as presented here is also proposed. The heating device is a gas heating device with a gas burner and a conveying device that can convey a pneumatic gas-air connection to the gas burner.

In particular, the use of an ionization signal of a flame to control an ignition process of a heating device with a pneumatic gas-air connection is proposed. Furthermore, the use of an ionization signal of a flame of a heating device with a pneumatic gas-air connection is also proposed to select a suitable start profile.

A method for starting up a heater, a computer program product, a control and regulating device, a heater and uses are therefore specified here, which at least partially solve the problems described with reference to the prior art. In particular, the method, the computer program, the control device and the heater each contribute at least to shortening the start-up behavior of a heater and preventing the occurrence of ignition attempts in border areas and thus significantly increasing operational safety. In addition, carrying out the method does not require any structural changes to a heater, which advantageously means that the invention can be implemented cost-effectively and, in addition, the complexity of a heating system is not increased.

• Fig. 1: einen Ablauf eines hier vorgeschlagenen Verfahrens,
• Fig. 2: einen Verlauf eines lonisationssignals während einer Inbetriebnahme eines Heizgerätes,
• Fig. 3: eine Leistungskurve einer Fördereinrichtung eines Startprofils für eine fette Gemischzusammensetzung,
• Fig. 4: eine Leistungskurve einer Fördereinrichtung eines Startprofils für eine magere Gemischzusammensetzung, und
• Fig. 5: eine Leistungskurve einer Fördereinrichtung eines Startprofils für eine lange Abgasanlage.

The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments given. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures and in particular the size relationships shown are only schematic. They show:

• Fig. 1 : a sequence of a procedure proposed here,
• Fig. 2 : a course of an ionization signal during commissioning of a heater,
• Fig. 3 : a performance curve of a conveyor of a starting profile for a rich mixture composition,
• Fig. 4 : a performance curve of a conveyor of a starting profile for a lean mixture composition, and
• Fig. 5 : a performance curve of a conveyor of a starting profile for a long exhaust system.

Fig. 1 shows, by way of example and schematically, the sequence of a method proposed here for starting up a heating device. When starting the method 0, a start profile 1 can be selected from a prioritization list. As a rule, a first start profile in the order of the prioritization list can be used to start and a start-up process 2 can be carried out with this start profile. The prioritization list can specify various start profiles, preferably stored in a memory of the heating device, in particular on a control and regulation device of the heating device. The prioritization list can specify an order of the start profiles, whereby the order can be designed in such a way that the start profile with the highest chance of success is at the top, and the other stored start profiles follow according to their chance of success. When starting the procedure for the first time, for example after a new heating device has been installed, a standard prioritization list can be used, which can be pre-installed by the manufacturer with a sequence of start profiles.

During the start-up process 2, the heater can be operated with the selected start profile, the start profile comprising a power curve for operating a conveyor device 3 and parameters for operating an ignition device 4. The conveyor device 3 can be a fan and the power curve can indicate a fan speed as the power of the conveyor device 3 as a function of time. The parameters for operating the ignition device 4 can be, for example, an intensity of the ignition spark and/or a frequency of the ignition spark.

During the start-up process 2, an ionization signal 5 of the flame can be detected. Parallel to the start-up process 2, an ignition control process 6 can be carried out, in which various operating parameters, such as the ionization signal 5, the opening time of a gas valve and the performance of the conveyor device 3 can be included. As part of the ignition control process 6, it can be determined whether the start-up process 2 was successful. If the start-up process 2 is successful, the heater can switch to a normal operating mode 7.

If the ignition control procedure 6 determines that the start-up process was not successful, a start-up counter 8 can be incremented. If the start-up counter 8 now indicates a maximum number of start-ups 2, the heater can go into a fault mode 9 and block further start-ups for safety reasons. In addition, the heater could indicate in fault mode that maintenance by a service technician is necessary.

If the start-up counter 8 has not yet reached the maximum number of start-ups 2, another start-up 2 can now be initiated. The next start-up 2 can be initiated with the start profile that follows in the order of the prioritization list.

Following or at least partially parallel to the ignition control method 6, an evaluation 10 of the start profile carried out can be carried out. The evaluation particularly includes the ionization signal 5 and evaluates the quality of the start process 2 and the start profile used.

Following the evaluation 10, the prioritization list 11 can be determined. When determining the prioritization list 11, it can be checked whether the order of the prioritization list has changed due to the evaluation 10 of the last start process 2 and the start profile used. The determination of the prioritization list 11 can then be made available for a future selection of a start profile 1.

If, for example, it is determined during several start-up processes 2 that the third start profile in the sequence of the prioritization list has led to a successful start-up process 2, the third start profile in the prioritization list can be moved to the first place in the sequence when determining the prioritization list 11. As a result, the heater can initiate a first start-up process 2 with this start profile during future start-up processes 2, thus shortening the overall duration of the start-up process.

According to an advantageous embodiment, a "successful" start profile, for example a start profile that has enabled a successful start in a large number of consecutive cases, can be further adjusted by adjusting one or more parameters. An advantageous adjustment could, for example, be a shortening of the ignition time in order to enable an even faster start-up process. If a problem occurs during a start-up process after adjusting a parameter, the adjustment can subsequently be reversed.

If it is determined that a first start profile (the most successful start profile with the best rating so far) determined in the context of multiple evaluations 10 and determinations of the prioritization list 11 no longer guarantees a successful start process 2, the (defined prioritization list) can be deleted and the standard prioritization list can be started again.

Fig. 2 shows an ionization signal 5 during a starting process 2. The diagram shows the strength of the ionization signal 5 over a time t. Ignition sparks 12 are emitted by an ignition device 4. The diagram shows an ionization signal 5 which, due to the technical equipment used, is lower the higher the quality of the measured flame.

At the start of an ignition process, the ionization signal 5 can assume a high value because there is no flame. Essentially at the same time as the opening time 13 of the gas valve 13, the ignition device 4 begins to generate ignition sparks 12. At a time 14, a first flame can be detected based on a significantly lower ionization signal 5. At a time 15, a loss of flame occurs. At a time 16, a stable flame forms.

Various indicators for an evaluation 10 of a start profile can be taken from an ionization signal 5. These can be in particular an ignition period 17 (period between the opening time 13 of the gas valve and the time 16 of the stable flame), a number of times 15 at which a loss of flame has occurred, a signal strength 18 of the stabilized flame and an intensity of a signal noise 17 of the stabilized flame.

Fig. 3 showed a performance curve 23 of a conveyor 3 for a (exemplarily selected) starting profile for a rich mixture composition. This performance curve 23 can also be used for a general starting profile. The diagram shows a fan speed n, which is given as a percentage of a performance of the conveyor, which corresponds to the maximum performance of the heater, as a function of time t. The representation in the Fig. 3 to 5 is for illustrative purposes only and is not to scale.

• Anfahren einer Fördereinrichtung 3 des Heizgerätes mit (erstem) Anstieg A1 18 von 150 U/min/0,1s [(Umdrehungen pro Minute) pro 100 Millisekunden] bis zu einer (ersten) Leistung L1 von 30%,
• Öffnen des Gasventils zu einem Öffnungszeitpunkt 20,
• Starten eines Zündvorganges zu einem Zündzeitpunkt 28 mit normalen Einstellungen,
• Warten für einen (ersten) Zeitraum D1 19 von 0,2s [Sekunden], zur Stabilisierung der Flamme, wobei die Leistung der Fördereinrichtung 3 weitestgehend konstant bleibt,
• steigern der Leistung der Fördereinrichtung 3 bis zu einer (zweiten) Leistung L2 von der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht mit hohem (zweiten) Anstieg A2 21 von 150 U/min/ 0,1s [(Umdrehungen pro Minute) pro 100 Millisekunden],
• mindern der Leistung der Fördereinrichtung auf eine (dritte) Leistung L3 von 30% mit einem (dritten) Anstieg A3 23 von - 100 U/min/0,1s [(Umdrehungen pro Minute) pro 100 Millisekunden],
• Ende der Leistungskurve 22 und Kontrolle der Flamme über das lonisationssignal 5.

The performance curve 23 of the conveyor device 3 for a starting profile for a rich mixture composition can, for example, have the following features:

• Starting a conveyor 3 of the heater with (first) increase A1 18 of 150 rpm/0.1s [(revolutions per minute) per 100 milliseconds] up to a (first) power L1 of 30%,
• Opening the gas valve at an opening time of 20,
• Starting an ignition process at an ignition point 28 with normal settings,
• Waiting for a (first) period D1 19 of 0.2s [seconds] to stabilize the flame, whereby the performance of the conveyor 3 remains largely constant,
• increasing the output of the conveyor 3 up to a (second) output L2 of the output of the conveyor, which corresponds to the maximum output of the heater with high (second) rise A2 21 of 150 rpm/ 0.1s [(revolutions per minute) per 100 milliseconds],
• reducing the performance of the conveyor to a (third) performance L3 of 30% with a (third) increase A3 23 of - 100 rpm/0.1s [(revolutions per minute) per 100 milliseconds],
• End of the power curve 22 and control of the flame via the ionization signal 5.

Fig. 4 showed a performance curve 24 of a conveyor 3 for a starting profile for a lean mixture composition. The representation is analogous to the Fig. 3 .

• Anfahren einer Fördereinrichtung 3 des Heizgerätes mit einem (ersten) Anstieg A1 18 von 150 U/min/0,1s [(Umdrehungen pro Minute) pro 100 Millisekunden], bis zu einer (ersten) Leistung L1 von 45% der Leistung der Fördereinrichtung 3, die der maximalen Leistung des Heizgerätes entspricht,
• Öffnen des Gasventils zu einem Öffnungszeitpunkt 20,
• Starten eines Zündvorganges zu einem Zündzeitpunkt 28 mit Einstellungen für eine magere Gemischzusammensetzung,
• Kein Warten (der (erste) Zeitraum D1 beträgt 0s [Sekunden]);
• Steigern der Leistung der Fördereinrichtung 3 bis zu einer (zweiten) Leistung L2 von 85% mit einem (zweiten) Anstieg A2 21 von 100 U/min/0,1s [(Umdrehungen pro Minute) pro 100 Millisekunden],
• Ende der Leistungskurve 22 und Kontrolle der Flamme über das lonisationssignal 5.

Durch einen geringeren Anstieg A2 kann es einem Regel- und Steuergerät des Heizgerätes erleichtert werden, auf eine geeignete Leistung zu regeln und eine Flamme zu stabilisieren. Dieses Startprofil ist besonders für magere Gemischzusammensetzungen geeignet, insbesondere in Verbindung mit kurzen Abgasanlagen.The performance curve 24 of the conveyor device 3 for a starting profile for a lean mixture composition can, for example, have the following features:

• Starting a conveyor 3 of the heater with a (first) increase A1 18 of 150 rpm/0.1s [(revolutions per minute) per 100 milliseconds], up to a (first) power L1 of 45% of the power of the conveyor 3, which corresponds to the maximum power of the heater,
• Opening the gas valve at an opening time of 20,
• Starting an ignition process at an ignition point 28 with settings for a lean mixture composition,
• No waiting (the (first) period D1 is 0s [seconds]);
• Increasing the power of the conveyor 3 up to a (second) power L2 of 85% with a (second) increase A2 21 of 100 rpm/0.1s [(revolutions per minute) per 100 milliseconds],
• End of the power curve 22 and control of the flame via the ionization signal 5.

A smaller increase A2 can make it easier for a heater's control and regulation device to regulate to a suitable output and to stabilize a flame. This starting profile is particularly suitable for lean mixture compositions, especially in conjunction with short exhaust systems.

Fig. 5 showed a performance curve 25 of a conveyor 3 for a starting profile for a long exhaust system. The representation is analogous to the Fig. 3 or 4.

• Anfahren einer Fördereinrichtung 3 des Heizgerätes mit einem (ersten) Anstieg A1 18 von 150 U/min/0,1s [(Umdrehungen pro Minute) pro 100 Millisekunden] bis zu einer (ersten) Leistung L1 von 72% der Leistung der Fördereinrichtung 3, die der maximalen Leistung des Heizgerätes entspricht,
• Öffnen des Gasventils zu einem Öffnungszeitpunkt 20
• Starten eines Zündvorganges zu einem Zündzeitpunkt 28 mit Einstellungen, die denen für eine magere Gemischzusammensetzung entsprechen,
• Warten für einen (ersten) Zeitraum D1 19 von 0,3s [Sekunden], zur Stabilisierung der Flamme, wobei die Leistung der Fördereinrichtung 3 weitestgehend konstant bleibt,
• Mindern der Leistung der Fördereinrichtung 3 bis zu einer (zweiten) Leistung L2 von 64% der der Leistung der Fördereinrichtung 3, die der maximalen Leistung des Heizgerätes entspricht einem (zweiten) Anstieg A2 21 von -600 U/min/0,1s [(Umdrehungen pro Minute) pro 100 Millisekunden],
• Warten für einen (zweiten) Zeitraum D2 26 von ca. 3s [Sekunden], wobei die Leistung der Fördereinrichtung 3 weitestgehend konstant bleibt,
• steigern der Leistung der Fördereinrichtung 3 auf eine (dritte) Leistung L3 zwischen 62% und 82% der Leistung der Fördereinrichtung, die der maximalen Leistung des Heizgerätes entspricht, mit einem (dritten) Anstieg A3, der ungefähr dem (ersten) Anstieg A1 18 entspricht,
• Ende der Leistungskurve 22 und Kontrolle der Flamme über das lonisationssignal 5.

The performance curve 24 of the conveyor device 3 for a starting profile for a long exhaust system can, for example, have the following features:

• Starting a conveyor 3 of the heater with a (first) increase A1 18 of 150 rpm/0.1s [(revolutions per minute) per 100 milliseconds] up to a (first) power L1 of 72% of the power of the conveyor 3, which corresponds to the maximum power of the heater,
• Opening the gas valve at an opening time 20
• Starting an ignition process at an ignition point 28 with settings corresponding to those for a lean mixture composition,
• Waiting for a (first) period D1 19 of 0.3s [seconds] to stabilize the flame, whereby the performance of the conveyor 3 remains largely constant,
• Reducing the power of the conveyor 3 to a (second) power L2 of 64% of the power of the conveyor 3, which corresponds to the maximum power of the heater, a (second) increase A2 21 of -600 rpm/0.1s [(revolutions per minute) per 100 milliseconds],
• Waiting for a (second) period D2 26 of approximately 3s [seconds], whereby the performance of the conveyor 3 remains largely constant,
• increasing the power of the conveyor 3 to a (third) power L3 between 62% and 82% of the power of the conveyor, which corresponds to the maximum power of the heater, with a (third) increase A3 which is approximately equal to the (first) increase A1 18 corresponds,
• End of the power curve 22 and control of the flame via the ionization signal 5.

list of reference symbols

0

start of the procedure

1

selection start profile

2

startup process

3

conveyor system

4

ignition device

5

ionization signal

6

ignition control procedure

7

normal operating mode

8

boot counter

9

jamming mode

10

Evaluation

11

definition of prioritization list

12

ignition spark

13

opening time of the gas valve

14

time of first flame

15

time of loss of flame

16

time of stable flame

17

signal noise

18

(first) climb A1

19

(first) period D1

20

opening time of the gas valve

21

(second) climb A2

22

end of the performance curve

23

power curve for rich mixture composition

24

power curve for lean mixture composition

25

performance curve for long exhaust system

26

(second) period D2

27

(third) climb A3

28

ignition timing

Claims (12)

1. Method for starting up a gas heater with a pneumatic gas/air assembly, wherein the heater is operated with a start profile during start-up and the start profile is adapted to the dynamic behaviour of the mixture composition and to the formation of a gas peak during an ignition procedure, and comprises at least one output curve (23, 24, 25) of a conveying apparatus (3) of the heater and an opening time (13, 20) of a gas valve, wherein the output curve (23, 24, 25) of a conveying device (3) of a start profile comprises at least the following processes:

   a) increasing the output of the conveying apparatus (3) up to an output L1 with an increase A1 (18)

   b) opening the gas valve after reaching the output L1 and initiating an ignition procedure,

   c) keeping the output L1 constant for a period D1 (19),

   d) controlling an output L2 of the conveying apparatus (3) with an increase A2 (21).
2. Method according to claim 1, wherein the following processes are additionally carried out:

   e) the power is kept largely constant for a period D2 (26),

   f) controlling an output L3 with an increase A3 (27).
3. Method according to any one of the preceding claims, wherein, after an unsuccessful starting procedure (1), a new starting procedure (1) is initiated with a different starting profile.
4. Method according to any one of the preceding claims, wherein after the method has been executed, an ignition control method (6) which comprises an evaluation of an ionisation signal (5) is initiated.
5. Method according to claim 3, wherein at least one of the following features of the ionisation signal (5) is included: period of time between an opening time (13, 30) of the gas valve and the first occurrence of the ionisation signal (5), number of occurrences of the ionisation signal (5) during an ignition procedure, strength of the ionisation signal (5), noise of the ionisation signal (5).
6. Method according to any one of claims 3 or 4, wherein the output of the conveying apparatus (3) when the ionisation signal (5) occurs is included in the evaluation of the ionisation signal (5).
7. Method according to any one of claims 4 to 6, wherein in the ignition control method (6) at least one evaluation (10) of the start profile carried out is performed and stored.
8. Method according to claim 7, wherein the order of the start profiles is selected on the basis of the at least one evaluation (10).
9. Method according to any one of claims 7 or 8, wherein the at least one evaluation (10) is deleted after a defined number of unsuccessful start procedures (1).
10. Heater having a pneumatic gas/air assembly and at least one conveying apparatus (3), a gas valve and a regulating and control appliance, wherein the regulating and control appliance is arranged to cause the heater to carry out the steps of the method according to any one of the preceding claims.
11. Computer program comprising commands that cause the heater of claim 10 to carry out the steps of the method according to any one of claims 1 to 9.
12. Machine-readable storage medium on which the computer program according to claim 11 is stored.

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