Heating system comprising a fuel-operated heater

Abstract

The invention relates to a heating system (10), in particular for heating a motor vehicle, comprising a fuel-operated heater (20) and a detection unit (61) which is configured to detect, at least for a first case in which no flame formation is present, whether fuel is present in the heater (20), in particular to detect not only for the first case in which no flame formation is present, but also for a second case in which flame formation is present.

Description

TECHNICAL FIELD

[0001] The invention relates to a heating system, in particular for heating a motor vehicle, a method for priming a heater with fuel, a method for starting, in particular for starting for the first time, a heater or a heating system, and the use of parameters pertaining to a firing device. BACKGROUND

[0002] WO 2014 / 044570 A1 describes a method for automatic priming of a line in a fuel-operated heating system with flame recognition. In this method, the line priming process is started, the heating system is controlled such that fuel is heated or a firing attempt is made during line priming, and the line priming process is ended when a flame is recognized.

[0003] In a first process step, the fuel line can be preprimed. Here, the operating time and the metering pump frequency should be chosen such that the fuel line is not overprimed (which would be detrimental to the heater), but the unprimed length should be as short as possible. For example, in the case of a truck, the line length can depend greatly on the respective vehicle, so that after prepriming, an unprimed line length of possibly up to several meters (for example 3 to 4 meters) also needs to be primed.

[0004] In a next process step, heating can be started, in which the metering pump is operated at an increased frequency (for example 3 Hz instead of the usual 1 Hz), if necessary deviating from the "normal start", until a flame is recognized. A line length of for example 4.5 m can be primed within a predetermined (maximum) first start time (for example 4 min) including all pre-warm-up times (for example 50 s), stabilization times (for example 40 s).

[0005] When starting a heater by means of an evaporation burner, it is basically advantageous for the relative start safety to work with a (initially) relatively low flow of combustion air (and a correspondingly small flame). However, as mentioned above, this is somewhat contradictory to the requirement for automatic first start.

[0006] If no flame is formed immediately, the heater can be significantly overprimed in a continuous (until possibly time-controlled shutdown), fuel-intensive start process. SUMMARY

[0007] It is therefore the task of the invention to propose a heating system in which fuel can be primed relatively quickly and the disadvantages associated therewith, such as the risk of overpriming the heater, can be reduced as much as possible. Furthermore, it is the task of the invention to propose a corresponding method for priming a heater, a method for starting a heater, and the use of parameters pertaining to a firing device.

[0008] This task is solved in particular by the features of claim 1.

[0009] This task is solved, inter alia, by means of a heating system, which is preferably used for heating a vehicle, preferably a motor vehicle, particularly preferably a passenger car and / or a utility vehicle, comprising a fuel-operated heater (with an evaporation burner) and a detection unit. The detection unit is configured to detect the presence (or the action) of fuel in the heater.

[0010] Preferably, the detection unit is configured to detect the presence of fuel in the heater at least for a (first) case in which no flame formation (or no successful ignition) takes place. Particularly preferably, the detection unit is configured to detect not only for the first case in which no flame formation (or no successful ignition) takes place, but also for a second case in which flame formation is present (i.e. ignition has already taken place successfully).

[0011] The core idea of the present application is that, when there is no flame (combustion), it is possible (by means of the detection unit) to recognize (detect) the action of fuel on the heater. In this way, it is possible to fill a relatively long (empty) fuel line (as is also possible in principle in the prior art) without problems. However, by recognizing a completed or successful filling even when no flame is formed, it is possible (significantly) to reduce the probability of an undesired overfilling. If necessary, a second start attempt (with flame formation or with conditions that promote ignition, if necessary deviating) can be carried out when the heater is started (initially started) within the time available for starting. In particular, a second start attempt with a correspondingly lean mixture can then be carried out. Here, it has also been recognized within the scope of the present application that, by means of the above-mentioned prior art (in particular by means of flame recognition by increasing the exhaust gas temperature), it is not possible to distinguish between a case in which fuel has not yet been acted upon and a case in which fuel is present, but combustion has not yet started.

[0012] The heating system can be defined by one (common) structural group, in particular by one common (external) housing. Alternatively, the heating system can also exist in the form of separate components, which are connected to one another (for example by means of an electrical connection and / or a fluid-conducting connection). According to a first alternative, the detection unit and the heater can in particular be components of one common structural group, for example such that the detection unit is arranged in the heater housing. Alternatively, the detection unit can also be arranged (at least partially, if necessary completely) externally with respect to the heater, in particular outside the heater housing.

[0013] The heater comprises in particular an (evaporation) burner. Furthermore, the heater preferably comprises at least one ignition device, in particular at least one glow plug, for igniting a fuel-air mixture.

[0014] The detection of the presence of fuel in the heater can be carried out directly (by directly detecting the presence of fuel) and / or indirectly (in particular by means of at least one parameter which is influenced by the fuel acting).

[0015] The detection unit is preferably configured to consider the same parameters (in particular the power consumption of the ignition device, preferably of the at least one glow pin) for the case in which no flame formation occurs as for the case in which flame formation is present (when the detection of the presence of fuel in the heater is carried out).

[0016] The detection unit is preferably configured to consider at least one parameter which is determined and / or evaluated (for example determined or evaluated for the electrical power required to adjust the ignition device, in particular the glow pin, to the desired temperature) in connection with at least one further function of the heater, in particular a control or regulation function.

[0017] The consideration of the parameters is in particular (in the context) to be understood as the use of the (respective) parameters when carrying out the detection, for example in the respective calculation and / or comparison and / or analysis carried out by the detection unit in general.

[0018] The heating system, in particular the heater, preferably comprises a control and / or calculation device (for example comprising a processor, in particular a microprocessor) in order to carry out the necessary manipulations and / or calculations. The control and / or calculation device can comprise or be configured at least in part by the detection unit. Conversely, the detection unit can also comprise (or be configured) at least in part by the control and / or calculation device. The control and / or calculation device can form one structural unit with the heater (for example arranged in one common housing) or be configured externally with respect to the heater and / or the detection unit. The functions of the heating system and / or the control and / or calculation method steps, which are preferably carried out by the control and / or calculation device or the control and / or calculation device is correspondingly configured, are described below.

[0019] Preferably, the detection unit is configured to consider at least one, in particular electrical operating parameter and / or settable operating parameter, if necessary adjustable operating parameter, of the heating system in order to carry out the detection. The operating parameter of the heating system is in particular to be understood as a parameter which influences the manner of operation of the heating system, for example the electrical power for operating one or more components. Parameters which are only derived from the current operation (for example parameters relating to the flame) are in particular not to be understood as operating parameters. In the consideration of such operating parameters, information which is already present (in the case of regulation) can be used in a synergistic manner, which simplifies the heating system in terms of construction and function.

[0020] Preferably, the same or identical parameters are considered for the detection when the detection is carried out in the first case and when the detection is carried out in the second case. However, it is also conceivable to consider different parameters, for example operating parameters (for example in particular the electrical power consumption of the ignition device) in the first case (in which no flame formation occurs) and other parameters in the second case, for example parameters relating to the flame formation (combustion), for example parameters relating to the exhaust gases (for example the temperature) caused by the combustion.

[0021] It is also conceivable to also take into account several parameters at the same time, for example an operating parameter (for example the electrical power for the ignition device / glow plug) and a further parameter (for example relating to the flame formation), i.e. preferably in the first and / or second case.

[0022] In an embodiment, the detection unit can be configured to take into account, for the purpose of performing the detection, at least one electrical parameter and / or a settable parameter, if necessary an adjustable parameter, which parameter is assigned to at least one ignition device, in particular at least one glow plug, of the heater. Thereby it is possible to simplify the detection of the presence of fuel in the heater, in particular by taking into account or using a parameter which has to be determined or ascertained as such (at least generally) anyway (in particular in the case of constant temperature regulation).

[0023] Preferably, the sensor unit is configured to detect the electrical power (power consumption) for the ignition device, in particular the glow plug. Here, in particular it is preferred to be able to determine (or to take into account in the detection) an increase in the electrical power consumption (in particular at a constant temperature of the ignition device or at a temperature which is regulated to a constant value), preferably an increase in the electrical power consumption and a decrease in the electrical power consumption (at a constant temperature or at a temperature which is regulated to a constant value). The increase in the electrical power consumption is to be understood in particular as an increase from a positive value to a (higher) positive value (> 0). Thus, the decrease is to be understood in particular as a change from a higher positive value to a lower positive value (> 0).

[0024] If the parameter, for example the power or the power consumption, is detectable or determinable, then preferably at least 10, further preferably at least 100 different (in particular time-dependent) parameter values can be detected or determined (in particular in relation to time) and can be evaluated accordingly by the detection unit or by the detection unit (this applies in particular to any other parameter, in particular the operating parameters mentioned above and / or below).

[0025] If the parameter, for example the power or the power consumption, is variable, in particular settable, then preferably at least 10, further preferably at least 100 different (in particular time-dependent) parameter values can be assumed, in particular set, for example by means of a calculation and / or control unit (this applies in particular also to any other parameter, in particular the operating parameters mentioned above and / or below).

[0026] Generally, the present application aims to be able to read off information (lack of) about the presence of fuel ("fuel action") by evaluating existing sensor values and / or measurement values. As a measured variable, here preferably the electrical power (and / or related parameters, for example the current and / or the voltage) are taken, which are necessary for keeping the temperature of the ignition device (glow plug temperature or glow plug resistance) constant (possibly steady-state at start-up).

[0027] The ignition device temperature (glow plug temperature) can be measured, for example, by means of the ignition device resistance or glow plug resistance.

[0028] Preferably, at least one measuring device is provided for measuring or determining the ignition device temperature.

[0029] In an embodiment, for example, the heating power necessary for the ignition device is increased from initially approximately 65 to 70 W (generally: first value) to (at least almost) 100 W (generally: second value) as soon as fuel is fed to the heater (combustion chamber) without a flame being formed. In this case, the ignition device (glow plug) is cooled by the fuel (for example, diesel).

[0030] Conversely, on completion of flame formation, the required electric heating power decreases (significantly) since the ignition device (glow plug) is also heated by the flame here.

[0031] Preferably, the temperature of the (at least one) ignition device, in particular at least one glow plug, is adjustable to a constant value (in particular by means of a corresponding calculation and / or control unit of the heating system or heater).

[0032] The detection unit is preferably configured to detect whether a flame is formed when fuel is present (detected) in the heater.

[0033] The (said) calculation and / or control unit of the heating system is preferably configured to carry out a (further) start-up attempt, in particular with a leaner mixture (compared to the fuel-air mixture at the first start-up attempt), if it is determined that there is no (lack of) flame formation when fuel is present (detected). There is thus the possibility of being able to carry out a second (regular or more robust) start-up attempt within the time available for the initial start-up.

[0034] Furthermore, the above-mentioned tasks are solved, in particular, by a method for charging (and thus initially charging) a heater (and / or a heating system, as described above and / or below) of a motor vehicle with fuel, comprising the following steps:

[0035] (a) supplying fuel to the heater by means of at least one fuel feed device;

[0036] (b) detecting the presence of fuel in the fuel chamber in the (first) case without flame formation.

[0037] Step b) is preferably carried out such that, in the case of no (presence of) flame formation, at least the presence of fuel in the heater is identified. Preferably, however, step b) is carried out such that the presence of fuel can be determined (detected) in any case (i.e. also in the case of flame formation).

[0038] Further method features result from the above explanations of the heating system, in particular the functional features there, which can be carried out in the method as corresponding method steps, in particular detection and / or control steps.

[0039] Preferably, at least one parameter is considered in step b), which parameter is assigned to at least one ignition device of the heater, in particular at least one glow plug.

[0040] In one embodiment of the method, the electrical heating power or power consumption of at least one ignition device, in particular at least one glow plug, is detected, preferably such that an increase in the electrical power consumption can be determined, in particular at a constant temperature of the ignition device or a constant regulated temperature of the ignition device, preferably not only an increase in the electrical power consumption but also a decrease in the electrical power consumption (and correspondingly for the detection of the acting fuel).

[0041] The temperature of at least one (said at least one) ignition device, in particular (said) at least one glow plug, is preferably regulated to a constant value.

[0042] The above task is solved in particular by a method for starting, in particular for starting up, in particular for starting up a heater and / or a heating system for a motor vehicle, preferably a method as described above and / or below, which method comprises the above method for charging, in particular for starting up, the heater.

[0043] In the method for starting, it is preferably detected whether flame formation occurs in the presence of (detected) fuel in the heater. Furthermore, it is preferably provided that, if it is determined that there is no (lack of) flame formation, a further start attempt is carried out (in particular with a lean mixture).

[0044] The above task is solved in particular by using a parameter, in particular the electrical power consumption (heating power) and / or a quantity derived therefrom, which is assigned to an ignition device, in particular a glow plug, of the heater, in particular of a heater for a motor vehicle, for detecting whether fuel is present in the heater at least in the (first) case of no flame formation (particularly preferably, the detection is carried out not only for the first case of no flame formation, but also for the second case of the presence of flame formation).

[0045] Further embodiments result from the dependent claims. BRIEF DESCRIPTION OF DRAWINGS

[0046] The application is explained in detail below on the basis of the embodiments illustrated in the drawings. Herein are shown:

[0047] Figure 1 : schematic diagram of one embodiment of a heating system according to the application;

[0048] Figure 2: first temperature-time curve for illustrating the present application; and

[0049] Figure 3 : second temperature-time curve for illustrating the present application.

[0050] In the following description identical reference signs are used for identical and identically acting parts. DETAILED DESCRIPTION

[0051] Figure 1 A heating system 10 is shown, which can be used for example in a vehicle interior. The heating system 10 comprises a heater 20, a dosing pump 30 and a tank 40, wherein the tank 40 can also be identical to a tank 40 which supplies a combustion engine of a motor vehicle. The heater 20 is fed with fuel via a fluid line, preferably defined as pressure line 41, through the dosing pump 30, wherein the dosing pump 30 conveys fuel from the tank 40 through a fluid line, preferably defined as suction line 42. Units 61, 62, like at least one detection unit 61 and if necessary a timer 62, provide or detect data about the heating system, wherein the heating system 10 further comprises a computing and / or control unit 50, which is connected for example through electrical lines 51 to 55 with the heater 20, the dosing pump 30 and the peripherals 61, 62. The computing and / or control unit 50 comprises or consists of a preferably electronic control unit.

[0052] The detection unit 61 can be an integral part of the computing and / or control unit 50 or be constructed separately. In this regard, Figure 1 Should be understood purely schematically.

[0053] The heater 20 preferably has a burner 21, a glow plug 22 and a combustion air blower 23, which are each electrically controllable and connected for example through electrical lines 51, 52, 57 with the computing and / or control unit (controller) 50. The burner 21 here burns an air and fuel mixture, wherein the glow plug 22 provides the heat required for igniting the air and fuel mixture. The heat for operating the heating process can be taken through a heat exchanger on the exhaust gas channel of the heater.

[0054] The dosing pump 30 is preferably constructed as an electromagnetic reciprocating piston pump, which has a controllable drive for conveying fuel from the tank. The drive can be constructed for example as an electromagnet with a coil, wherein the coil moves the reciprocating piston in an electromagnetic manner due to an electrical energization, which is controllable by the computing and / or control unit (controller) 50, for conveying fuel. The dosing pump 30 thus preferably has a controllable conveying frequency, with which the reciprocating piston moves back and forth in the coil. However, other types of dosing pumps can also be involved, for example diaphragm pumps or gear pumps, which have a controllable, preferably electric or electromagnetic drive and can be controlled analogously.

[0055] The computing and / or control unit (controller) 50 can receive data signals from the detection unit 61 and, if necessary, from the timer 62 and use these data signals for controlling the heater 20 and components of the heater: burner 21, glow plug 22 and / or combustion air blower 23 and / or dosing pump 30, depending on the embodiment, when the detection unit itself is not an integral part of the computing and / or control unit.

[0056] Here, a routine for calculating control commands for controlling the heater 20, components 21, 22 of the heater and / or dosing pump 30 can be run on the processor unit 56 of the computing and / or control unit (controller) 50, wherein the computing and / or control unit (controller) 50 sends control signals for controlling the heater 20, components 21, 22, 23 of the heater and / or dosing pump 30 via electrical lines 51 to 53.

[0057] It is understood that the computing and / or control unit (controller) 50 can cause energization of a drive, for example a coil or an electric motor, of the dosing pump 30. It is also possible that the heater 20 and the dosing pump 30 each have their own computing and / or control unit, wherein the respective computing and / or control unit, if necessary, interprets the control signals sent by the computing and / or control unit (controller) 50 and controls the dosing pump and the heater and components thereof itself.

[0058] The computing and / or control unit (controller) 50 can also receive data signals indirectly from a central control device via a CAN or LIN bus system, if necessary. It is understood that the computing and / or control unit (controller) 50 can be an integral part of the heater 20 or be constructed as a separate component.

[0059] The detection unit 61 is configured to derive from the electrical power used for the operation (heating or holding) of the glow plug whether fuel is acting (present) in the heater, as explained in more detail below.

[0060] Figure 2 A graph showing the glow plug temperature GT or the electrical drive power P of the glow plug as a function of time t is shown. From the point in time 0 (origin of the coordinate system) or shortly thereafter, the glow plug is supplied with electrical power (in the present case 65 W), so that after a certain period of time (at the point in time tS = shortly before the start of fuel delivery) its predetermined temperature (in the present case, for example, 1200°C) is reached. Thereafter, fuel delivery is started (at the point in time tS). In order to maintain the temperature constant, the power is adjusted accordingly, which can be seen from the serpentine course between the points in time tS and tB (= fuel acting on the heater).

[0061] At the point in time tB, fuel (BS) acts on the heater (for the first time). In this heater, the temperature of the glow plug is also kept constant by correspondingly adjusting the power. However, because of the heat generated by the combustion, the electrical power required for keeping the temperature (in the present case 1200°C) constant drops. By evaluating the electrical power (in particular the change in the electrical power over time), the detection unit (61) now detects, on the one hand, that fuel is actually acting on the heater; on the other hand, that this takes place in the case of flame formation. In this case, the corresponding start-up attempt is carried out as normal.

[0062] Figure 3 A curve similar to Figure 2 is shown. However, in contrast to Figure 2 here, no flame formation takes place directly after the time tB in which fuel is acting on the heater. Rather, in particular, the temperature and power profiles correspond to those up to the point in time tB in Figure 2 in which fuel is acting on the heater.

[0063] Even thereafter, the temperature profile corresponds to Figure 2 to some extent, because in Figure 3 the temperature is also kept at a constant value (here, for example, also 1200°C). However, because no flame formation and thus no support by the heat input of the flame takes place, but the amount of fuel which is still present now evaporates by means of electrical energy, an increasing power is now required in order to keep the temperature at the desired value. In contrast to Figure 2 the power curve rises (rather than drops). Here, the detection unit also evaluates this profile (in particular the increase or rise in the power consumption), so that it is possible to reliably (and relatively quickly) identify the action of fuel.

[0064] It should be noted here that all the above-described parts are only considered individually and that the details shown in the figures are essential to the invention in each combination. Variations from the above are familiar to the person skilled in the art.

[0065] List of reference signs

[0066] 10 heating system

[0067] 20 heater

[0068] 21 burner

[0069] 22 glow plug

[0070] 23 combustion air blower

[0071] 30 dosing pump

[0072] 40 tank

[0073] 41 line section, pressure line

[0074] 42 line section, suction line

[0075] 50 computing and / or control unit (controller)

[0076] 51 electrical line

[0077] 52 electrical line

[0078] 53 electrical line

[0079] 54 electrical line

[0080] 55 electrical line

[0081] 56 processor unit

[0082] 57 electrical line

[0083] 61 detection unit

[0084] 62 timer

Claims

1. A heating system (10) for heating a motor vehicle, comprising a fuel-operated heater (20) and a detection unit (61) configured to detect, at least in the first case where flame formation is absent, the presence of fuel in the heater (20). Its features are, The detection unit (61) is configured to take into account the electrical power consumption of at least one ignition device in order to perform the detection, wherein the control device of the heating system (10) is further configured to perform a further start-up attempt with a lean mixture if it is determined that no flame is formed when fuel is applied.

2. The heating system (10) according to claim 1, characterized in that, The detection unit (61) is configured to take into account at least one operating parameter of the heating system (10) in order to perform the detection.

3. The heating system (10) according to claim 1 or 2, characterized in that, The detection unit (61) is configured to consider at least one parameter for performing the detection, the parameter being associated with at least one ignition device of the heater (20).

4. The heating system (10) according to claim 1 or 2, characterized in that, The temperature of at least one ignition device can be adjusted to a constant value.

5. The heating system (10) according to claim 1 or 2, characterized in that, The detection unit (61) is configured to detect whether flame formation occurs when fuel is present in the heater (20).

6. The heating system (10) according to claim 1 or 2, characterized in that, The detection unit (61) is configured to detect the presence of fuel in the heater (20) not only in the first case where no flame is formed, but also in the second case where flame is formed.

7. The heating system (10) according to claim 1 or 2, characterized in that, The at least one ignition device is at least one incandescent plug (22).

8. The heating system (10) according to claim 1 or 2, characterized in that, The detection unit (61) is configured to take into account the power consumption of at least one ignition device in order to perform the detection, so that an increase in at least the power consumption can be determined.

9. The heating system (10) according to claim 1 or 2, characterized in that, The detection unit (61) is configured to consider the power consumption of at least one ignition device in order to perform the detection, so that it can determine not only an increase in the power consumption, but also a decrease in the power consumption.

10. The heating system (10) according to claim 2, characterized in that, The operating parameters are at least one electrical operating parameter and / or settable operating parameters of the heating system (10).

11. The heating system (10) according to claim 3, characterized in that, The parameter is at least one electrical parameter and / or a settable parameter.

12. The heating system (10) according to claim 10, characterized in that, The operating parameters are at least one electrical operating parameter and / or a settable, adjustable operating parameter of the heating system (10).

13. The heating system (10) according to claim 11, characterized in that, The parameter is at least one electrical parameter and / or a settable, adjustable parameter.

14. A method for starting a heater (20) and / or a heating system (10) according to claim 1, wherein, The method includes a method for charging a heater (20) with fuel, having the following steps: (a) Fuel is supplied to the heater (20) via at least one fuel delivery device; (b) Detection in the absence of flame formation: the presence of fuel in the heater (20), wherein the power consumption of at least one ignition device is taken into account. The method is characterized in that, in the method for starting the heater and / or heating system, if it is determined that no flame formation is present, a further start-up attempt is performed with a thin mixture.

15. The method for starting a heater and / or a heating system according to claim 14, characterized in that, The method is configured for initial startup of the heater (20) and / or the heating system (10).

16. The method for starting a heater and / or heating system according to claim 14 or 15, characterized in that, The heater (20) and / or the heating system (10) are configured for heating a motor vehicle.

17. The method for starting a heater and / or heating system according to claim 14 or 15, characterized in that, Detect whether flame formation occurs when fuel is present in the heater (20).

18. The method for starting a heater and / or a heating system according to claim 14, characterized in that, In step b), at least one parameter is considered, which is associated with at least one ignition device of the heater (20).

19. The method for starting a heater and / or a heating system according to claim 14, characterized in that, Adjust the temperature of at least one ignition device to a constant value.

20. The method for starting a heater and / or a heating system according to claim 18 or 19, characterized in that, The at least one ignition device is at least one incandescent plug (22).

21. The method for starting a heater and / or a heating system according to claim 14, characterized in that, Taking into account the power consumption of at least one ignition device, it becomes possible to determine at least the increase in electrical power consumption.

22. The method for starting a heater and / or a heating system according to claim 21, characterized in that, The power consumption of at least one ignition device is considered so that not only can an increase in the power consumption be determined, but also a decrease in the power consumption can be determined.

Images