Method for controlling the start of a heating device with a burner

Abstract

The invention relates to a method for controlling the start of a heating device (12) with a burner (13) and a combustion chamber (20), to which combustion air and fuel gas are supplied as a mixture via a supply channel, which includes an ignition device (14) for a fuel gas-air mixture and a control unit (15), wherein the method comprises at least the following steps: a. Performing a start sequence comprising a plurality of predetermined ignition parameter settings (1, 2, 3, 4, 5) which are activated successively, b. Identifying the ignition parameter setting (1, 2, 3, 4, 5) that caused successful ignition, and c. Determining the sequence of the predetermined ignition parameter settings (1, 2, 3, 4, 5) for a subsequent start sequence. Furthermore, a control unit (15) for controlling the method and a computer program for executing the control of the method are proposed.

Description

[0001] The invention relates to a method for controlling the start-up of a heating device with a burner. Furthermore, a control unit for controlling the method and a computer program product for executing the control of the control unit are specified.

[0002] The start-up of a heater with a burner is subject to various environmental fluctuations, including at least a variation in intake air temperatures, gas pressures, and / or a change in the installation conditions. The combination of various influences can lead to (unexpected) noises and / or delays occurring during the start-up of a heater. Disturbing noises are caused in particular by uncontrolled ignitions during a start-up with an incorrectly set fuel gas-air mixture composition with an excessively high proportion of fuel gas. Ignition delays can occur if the current fuel gas-air mixture composition contains too high a proportion of air during a start-up. Such events during the start-up of a heater can reduce the robustness of the heater and / or cause it to fail.

[0003] Especially when such problems occur, it's difficult to initiate quick and appropriate countermeasures that lead to stable ignition. If this isn't done quickly enough, a user who wants heated domestic water, for example, won't be able to access it quickly enough, thus suffering a loss of comfort.

[0004] In addition, the initial setup of a heater with regard to suitable ignition conditions is time-consuming, e.g., setting new ignition conditions and / or storing them in the device. This can make the installation of such systems time-consuming and costly, or even prone to failure.

[0005] The object of the invention is therefore to at least alleviate the problems described with reference to the prior art. In particular, the object of the invention is to ensure that a heater can be started (quickly) without disturbing noises and / or undesirable delays, thus increasing robustness and / or preventing failure.

[0006] This object is achieved according to the features of claim 1. Advantageous further developments are specified in the dependent claims. It should be noted that the features specified in the claims can be combined with one another in any technologically expedient manner and can characterize further embodiments of the invention. The description, particularly in conjunction with the figures, explains the invention and also discloses additional embodiments of the invention.

[0007] To solve this problem, a method for controlling the start of a heater with a burner and a combustion chamber, to which combustion air and fuel gas are supplied as a mixture via a supply channel, contributes. The heater also includes an ignition device for a fuel gas-air mixture and a control unit. The method comprises at least the following steps: a. Performing a start sequence comprising a plurality of predetermined ignition parameter settings that are activated sequentially, b. Identifying the ignition parameter setting that caused a successful ignition, and c. Determining the order of the predetermined ignition parameter settings for a subsequent start sequence.

[0008] The above-mentioned steps a., b., and c. can be performed in the specified order, but this is not mandatory. In particular, it is possible for the steps to overlap at least partially, be performed at different locations, and / or be repeated with different frequencies.

[0009] The control of the start-up of a heater with a burner can influence the ignition parameters of the air supply, the fuel gas supply, and / or the ignition via an ignition device in a time-dependent manner. The ignition parameters can be preset in an ignition parameter setting, which specifies a temporal sequence of the ignition parameters.

[0010] The ignition device enables the ignition of a mixture of air and fuel gas provided there, e.g., by means of an ignition spark. The ignition device can be provided in a combustion chamber of the heater's burner.

[0011] The control unit influences the amount of supplied air and / or fuel gas as well as the timing of the ignition spark. The control unit is configured to activate the ignition device.

[0012] The start sequence according to step a is carried out by activating predetermined ignition parameter settings one after the other by the control unit. The sequence of the ignition parameter settings is predetermined. The ignition parameter settings can differ in their characteristics, but can also have the same characteristics.

[0013] A start sequence comprises, for example, at least three or at least five predetermined ignition parameter settings, which are also executed in a predetermined order. The start sequence is performed by setting the first ignition parameter setting (also called the initial ignition parameter setting) and activating the ignition device. If no successful ignition is identified, the ignition is automatically adjusted to the subsequent second ignition parameter setting and activated the ignition device. If this does not result in a stable flame, the ignition continues with the subsequent ignition parameter setting, and so on.

[0014] Step a. is completed when an ignition parameter setting has led to a stable ignition of the fuel gas-air mixture or an ignition was "successful."

[0015] The ignition parameter setting according to step b. that results in successful ignition is identified at the end of or after the start sequence or step a. The control unit checks for the presence of a flame in the burner, for example, using a sensor or flame detector. The current or successful ignition parameter setting can be marked.

[0016] According to step c., the order of the predetermined ignition parameter setting for a subsequent start sequence is determined based on the result of step b.

[0017] If it is identified in step b. that a successful ignition was caused by the first ignition parameter setting (start ignition parameter setting), it can be specified in step c. that the next start sequence (step a.) will also start with the same first ignition parameter setting. If, on the other hand, it is identified in step b., for example, that a successful ignition was not caused by the first ignition parameter setting, but by the second (or a further) ignition parameter setting, it can be specified in step c. that the previously second (or further) ignition parameter setting will then be used as the first ignition parameter setting in the next start sequence (step a.). In this case, it is particularly possible for the two ignition settings to swap places in the sequence and / or for the newly successful ignition parameter setting to be placed before all others.It is possible to perform particularly promising ignition parameter settings, in particular those determined in step b., several times in step c. and / or to execute them more frequently.

[0018] In particular, the predetermined ignition parameter settings themselves are not adjusted, but the majority of such optional, stored or retrievable ignition parameter settings are only rearranged.

[0019] Such an ignition parameter setting may include variation ranges that may take into account, for example, an ignition time, a stabilization time and / or a heating power.

[0020] The ignition time comprises, in particular, a period during which the ignition device emits an ignition spark at predetermined intervals. The supply of fuel gas and air can be kept constant or varied during the ignition time. The ignition time ends with a successful ignition and / or after the predetermined ignition parameter setting has been reached.

[0021] The ignition time is preferably at least 0.5 to 5.0 s [seconds], in particular 1.5 to 2.5 s. The range proposed here enables robust ignition with a low risk of multiple ignitions. The ignition time is particularly preferably 1.5 to 2.0 s. If the lower limit is exceeded, there is a risk of multiple ignitions occurring during the further course of the ignition phase, including undesirable noise. If the upper limit is exceeded, successful ignition can no longer be guaranteed.

[0022] The ignition device preferably emits ignition sparks at intervals of at least 30 to 250 ms [milliseconds] or 4 to 30 Hz during the ignition period. The range proposed here ensures high availability of an ignition source within the available ignition period. Particularly preferably, the ignition device emits ignition sparks at intervals of 40 to 60 ms during the ignition period. If the lower limit is exceeded, there is a risk that a slightly delayed ignition will lead to increased noise pollution. If the upper limit is exceeded, it can lead to a reduction in the service life of the components.

[0023] The stabilization period covers a period immediately after the ignition time and after successful ignition. During the stabilization period, after successful ignition, the burner checks whether the flame is stable. During the stabilization period, further variable control of the ignition spark, fuel gas, and / or air can occur. The stabilization period can also be added to step a.

[0024] The stabilization time is preferably at least 3.0 s [seconds]. The range proposed here allows a flame to stabilize in the burner. The stabilization time is particularly preferably between 0 and 5.0 s. If the lower limit is exceeded, there is a risk that a stable flame will not be generated in the burner, and the flame may extinguish or explode. If the upper limit is exceeded, the heater cannot be used for too long after start-up, which negatively impacts user-friendliness. Connected domestic hot water operation is only possible without compromising comfort after a stabilization period.

[0025] After the flame has (successfully) stabilized, the system can then transition to the usual control / modulation mode, which then represents regular operation of the heater. In control mode, control and regulation are carried out based, for example, on the (heating) demand of the connected domestic hot water system.

[0026] At least one of the ignition parameter settings includes a varying fuel-air mixture composition. "Varying" in this context specifically means that at least one ignition parameter is changed over time at a predetermined ignition parameter setting. The time-varying ignition parameter can be selected from the following group: fuel supply (or valve opening), air supply (or fan speed), ignition energy. The ignition parameter settings can characterize or determine the fuel-air mixture composition.

[0027] The ignition parameter settings can determine an increase in the proportion of fuel in the fuel-air mixture composition over time. The increase does not have to be constant, but can occur in steps or ramps, or even be quadratic in nature.

[0028] The variation ranges of subsequent ignition parameter settings may partially overlap. An overlap occurs when the successively activated ignition parameter settings encompass situations in which the same ignition parameters apply, in particular the same fuel-air mixture composition. For example, if an ignition parameter is varied from 100% to 120% in a first ignition parameter setting, a partial overlap occurs if the subsequent ignition parameter setting varies the ignition parameter from 110% to 130%.

[0029] For step c, the section of the variation range in which successful ignition was detected can be taken into account. The variation range of the ignition parameter can be divided into different sections. It is possible to record at which section of the specified ignition parameter setting the ignition occurred. This information can also be used to determine the sequence for the next start.

[0030] The control unit records measured values ​​from the start-up sequence up to the successful ignition parameter setting. If necessary, values ​​for ignition parameter settings before and / or after the successful ignition parameter setting are also determined. Furthermore, it can record the specific time during the successful ignition parameter setting that the burner ignited.

[0031] In step c, a previous ignition parameter setting can be defined as the initial ignition parameter setting if successful ignition was determined in an initial section of the variation range and the previous ignition parameter setting demonstrated a leaner fuel-air mixture composition. The burner ignition occurred in a lean range of the ignition parameter setting. This range can overlap with or be close to a rich range of the previous ignition parameter setting. With a high probability, a burner start sequence can thus be performed with the previous ignition parameter setting at the next start, ensuring reliable burner ignition.

[0032] In step c, the same ignition parameter setting can be specified as the initial ignition parameter setting if successful ignition was determined in a central section of the variation range. The burner ignition thus occurred in a central section of the ignition parameter setting. The ignition parameter settings are designed, for example, so that the central sections do not overlap with the variation ranges of the previous and subsequent ignition parameter settings.

[0033] In step c., a subsequent ignition parameter setting can be defined as the starting ignition parameter setting if successful ignition was determined in a final section of the variation range and the subsequent ignition parameter setting demonstrated a richer fuel-air mixture composition. The burner thus ignited in a richer range of the ignition parameter setting. This range can overlap with or be close to a lean range of the subsequent ignition parameter setting. With a high probability, a burner start sequence can thus be performed at the next start with the subsequent ignition parameter setting, ensuring reliable burner ignition.

[0034] An initial start sequence, which follows the initial switch-on of the heater, has a plurality of predetermined ignition parameter settings, with the successively activated ignition parameter settings comprising a richer fuel gas-air mixture composition. The "initial" start sequence is particularly characterized by a set of ignition parameter settings that are factory-preset by the manufacturer of the heater and / or the control unit and stored there. This thus applies to the situation when the heater is first put into operation after installation. It is possible that the control unit provides at least three ignition parameter settings for this purpose, with the lambda to be set being reduced with the subsequent ignition parameter settings.

[0035] The order of the activated ignition parameter settings or the determination of the order of the predetermined ignition parameter settings for a subsequent start sequence can be adjusted taking environmental parameters into account. In other words, the method can detect and take into account the characteristics of the environmental parameters present before and / or during ignition. These can then be used, for example, before step a. and / or during step c. to (re)determine the order of the predetermined ignition parameter settings for the (immediately) subsequent start sequence.

[0036] The ambient parameters can be selected from the group: outside temperature, air humidity, time until the last start-up of the heater (overnight and / or over the summer), fuel composition, burner temperature (heater still hot after only a short switch-off time).

[0037] During the stabilization period following a successful ignition attempt, the burner's flame behavior can be evaluated, and flame behavior errors can be taken into account in step c. Flame behavior errors can result in deflagration or uncontrolled flame extinguishing. Thus, an ignition parameter setting that is used to ignite an unstable flame can be postponed or de-prioritized when determining the new sequence of ignition parameter settings.

[0038] In step c, at least one of the ignition parameters can be adjusted to the ignition parameter setting determined in step b. For example, the temporal change of the ignition parameter in this ignition parameter setting can be (permanently) adjusted or saved and used for subsequent start sequences.

[0039] Sections of the ignition parameter setting variation range in which successful ignition has been determined can be modified by varying the gradient. Varying the gradient can reduce the rate of change in the fuel-air mixture composition, thus preventing an excessive fuel fraction from being exceeded, which could cause a deflagration. This can be achieved by varying the gradient of the variation range, in which the gradient is reduced shortly before the expected successful ignition. This allows a critical range in which ignition can occur to be passed through more slowly or with greater certainty.The described gradient variation can be particularly preferably applied if a subsequent ignition parameter setting is defined as the starting ignition parameter setting, and if successful ignition was determined in an end section of the variation range of this starting ignition parameter setting. Then, the initial and / or middle section could be changed or passed through more quickly, and the final section (significantly) more slowly.

[0040] Furthermore, a heating device with a burner, having an ignition device for a fuel gas-air mixture, and means adapted to carry out the steps of the method contribute to solving the problem. The heating device can receive information about the flame behavior and control the air supply, the fuel gas supply, and the ignition device. The heating device can be part of a property's domestic hot water system or be pre-designed and configured for this purpose.

[0041] The heater comprises, in particular, a burner, which can be used to heat a domestic hot water system. The combustion chamber has a supply duct through which combustion air and (gaseous) fuel can be supplied as a mixture, and an exhaust duct through which combustion exhaust gases can be discharged. The mixture in the burner can be ignited via an ignition device. The control unit can be integrated into the heater.

[0042] Furthermore, a computer program product comprising commands that cause the heater to execute the method steps contributes to solving the problem. The computer program product can receive, store, and / or process information / data or (determined and / or measured) value parameters regarding the flame behavior from the heater.

[0043] The invention and the technical environment are explained in more detail below with reference to four figures. The representations are schematic and not intended to illustrate proportions. The explanations given with reference to individual details of the figures are extractable and can be freely combined with facts from the above description, unless something else necessarily follows for a person skilled in the art or such a combination is explicitly excluded. It shows schematically: Fig. 1 : a graphical view of an exemplary process flow with two start sequences and five ignition parameter settings Fig. 2 : a graphical representation of an exemplary first ignition parameter setting Fig. 3 : a graphical representation of an exemplary second ignition parameter setting Fig. 4 : schematic representation of a heater with connected control unit.

[0044] Fig. 1 shows a graphical view of an exemplary process flow with two start sequences and five ignition parameter settings each.

[0045] It shows (above) an initial start sequence 6 and a subsequent start sequence 7 below, in which the ignition parameter settings, which show a fuel-air mixture composition with an increasing fuel fraction, were re-sorted after the procedure was performed. This will now be explained.

[0046] During the initial start sequence 6, the control and regulation unit of the heater accesses a predetermined sequence of ignition parameter settings and is configured to carry them out in the initial sequence: first ignition parameter setting 1, second ignition parameter setting 2, third ignition parameter setting 3, fourth ignition parameter setting 4 and fifth ignition parameter setting 5 (see step a. of the method).

[0047] Now, a first unsuccessful ignition attempt was made with the first ignition parameter setting 1 and then an ignition 8 with the second ignition parameter setting 2. This was determined in step b. of the method.

[0048] As part of step c of the process, a new sequence was established, namely that the second ignition parameter setting 2 has the highest priority and is preceded in the next start sequence. It was even specified that the highest-priority ignition parameter setting would be executed several times before a further ignition parameter setting was performed.

[0049] For the subsequent start sequence 7, the ignition parameter settings were reordered, after which the second ignition parameter setting 2 is placed at the beginning and run through twice. If no ignition occurs in the two attempts with the second ignition parameter setting 2, a third attempt follows with the first ignition parameter setting 1, followed by attempts with the second ignition parameter setting 2 and the third ignition parameter setting 3.

[0050] Fig. 2 shows a graphical representation of an exemplary first ignition parameter setting 1. The first ignition parameter setting 1 comprises a varying fuel-air mixture composition with an increasing fuel proportion. During the increase, an ignition 8 occurs. Up to the ignition 8, an ignition time 9 occurs. The ignition time 9 is followed by a stabilization time 10. The stabilization time 10 has a smooth transition to a control / modulation 11. During the stabilization time 10 and in the smooth transition to the control / modulation 11, the fuel proportion increases to a maximum, from which it remains constant.

[0051] Fig. 3 shows a graphical representation of an exemplary second ignition parameter setting 2. The second ignition parameter setting 2 has a gradient variation of the varying fuel-air mixture composition with increasing fuel proportion, in which the gradient of the second ignition parameter setting 2 is reduced before an expected ignition 8 (based on the determination in step b. of the previous start sequence).

[0052] Fig. 4shows a schematic representation of a heater 12 with a connected control unit 15 and computer program / network 17. The heater 12 has a heat exchanger, whereby the heat generated by a burner 13 is transferred to a pipe of a domestic hot water system or a heating system 16. The burner 13 has a combustion chamber 20. The combustion chamber 20 has a combined ignition device 14, here with combined flame monitoring. The ignition device 14 and the flame monitoring are controlled via the control unit 15. The ignition device 14 can ignite a mixture in the combustion chamber 20, and the flame monitoring device 14 can monitor the maintenance of the ignited flame in the combustion chamber 20.

[0053] An exhaust pipe 19 is connected to the combustion chamber 20, which releases exhaust gases into the environment via an exhaust system 24.

[0054] A conveyor device 21 is connected to a burner door 27 of the combustion chamber 20. The conveyor device 21 is controlled by a speed controller 23, which in turn is controlled by the control unit 15. A mixture channel 25 is located upstream of the conveyor device 21. A fuel and combustion air are mixed in the mixture channel 25.

[0055] The fuel is supplied via a gas valve 22 located upstream of the mixture channel 25, which is controlled by the control unit 15. The gas valve 22 receives the fuel via a gas supply 28. Combustion air is supplied to the mixture channel 25 via a combustion air supply 18. A mass flow sensor 26 is located in the combustion air supply 18.

[0056] A computer program / network 17 is connected to the control and regulation unit 15. The computer program 17 controls the control and regulation unit 15 and provides information from the network 17, which is incorporated into the control and regulation unit 15. Information from the network 17 includes, for example, environmental parameters that can be selected from the following group: outside temperature, air humidity, time until the heater 12 was last started (overnight and / or during the summer), fuel composition in the conveyor system 21, and temperature of the burner 13 (heater 12 still hot after only a short shutdown time). List of reference symbols

[0057] 1 First ignition parameter setting 2 Second ignition parameter setting 3 Third ignition parameter setting 4 Fourth ignition parameter setting 5 Fifth ignition parameter setting 6 Initial start sequence 7 Subsequent start sequence 8 Ignition 9 Ignition time 10 Stabilization time 11 Control / Modulation 12 Heater 13 Burner 14 Ignition device 15 Control and regulation unit 16 Domestic hot water / heating system 17 Computer programming / network 18 Combustion air supply 19 Exhaust pipe 20 Combustion chamber 21 Conveying device 22 Gas valve 23 Speed ​​controller 24 Exhaust system 25 Mixture duct 26 Mass flow sensor 27 Burner door 28 Gas supply

Claims

1. A method for controlling the start of a heater (12) with a burner (13) and a combustion chamber (20) to which combustion air and fuel gas are supplied as a mixture via a supply channel, further comprising an ignition device (14) for a fuel gas-air mixture and a regulating and control unit (15), the method comprising at least the following steps: a. carrying out a start sequence comprising a plurality of predetermined ignition parameter settings (1, 2, 3, 4, 5) which are activated one after the other, b. identifying the ignition parameter setting (1, 2, 3, 4, 5) which causes a successful ignition (8), and c. determining the order of the predetermined ignition parameter settings (1, 2, 3, 4, 5) for a subsequent start sequence.

2. Method according to the preceding claim, wherein at least one of the ignition parameter settings (1, 2, 3, 4, 5) comprises a varying fuel gas-air mixture composition.

3. Method according to the preceding claim, wherein the variation ranges of subsequent ignition parameter settings partially overlap one another.

4. Method according to one of the preceding claims 2 or 3, wherein for step c. it is taken into account in which section of the variation range the successful ignition (8) was determined.

5. The method according to one of the preceding claims 2 to 4, wherein - in step c. a previous ignition parameter setting is defined as the start ignition parameter setting if the successful ignition (8) was determined in an initial section of the variation range and the previous ignition parameter setting had a leaner fuel-air mixture composition, - in step c. the same ignition parameter setting is defined as the start ignition parameter setting if the successful ignition (8) was determined in a central section of the variation range, and / or - in step c. a subsequent ignition parameter setting is defined as the start ignition parameter setting if the successful ignition (8) was determined in an end section of the variation range and the subsequent ignition parameter setting had a richer fuel-air mixture composition.

6. The method according to any one of the preceding claims, wherein an initial start sequence (6) following an initial switch-on of the heater (12) comprises a plurality of predetermined ignition parameter settings (1, 2, 3, 4, 5), wherein the successively activated ignition parameter settings comprise a richer fuel gas-air mixture composition.

7. Method according to one of the preceding claims, wherein a sequence of the activated ignition parameter settings is adapted taking environmental parameters into account.

8. Method according to the preceding claim, wherein the environmental parameters are selected from the group consisting of outside temperature, air humidity, time until the last start-up of the heater, fuel composition, burner temperature.

9. Method according to one of the preceding claims, wherein in a stabilization time (10) after a successful ignition attempt, the flame behavior of the burner is evaluated and errors in the flame behavior can be taken into account in step c.

10. Method according to one of the preceding claims, wherein in step c. at least one of the ignition parameters is adapted to the ignition parameter setting determined in step b.

11. A heating device (12) with a burner (13) having an ignition device (14) for a fuel gas-air mixture, and means adapted to carry out the steps of the method according to claim 1.

12. A computer program product comprising instructions that cause the heating device (12) of claim 11 to carry out the method steps according to any one of claims 1 to 10.

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