Burner system for an exhaust stream of an internal combustion engine with a fuel heating device and an oxygen gas heating device

Abstract

A burner system (1) for an exhaust stream (5) of an internal combustion engine comprises a combustion chamber (3), a fuel injector (6) for introducing fuel into the combustion chamber (3), a fuel supply (8) for supplying fuel to the fuel injector (6), and an oxygen gas supply (15) for supplying oxygen gas to the combustion chamber (3). A fuel heating device (14) is associated with the fuel injector (6), and an oxygen gas heating device (18) is associated with the oxygen gas supply (15). When the burner system (1) is started, the fuel heating device (14) is operated if the fuel temperature is below a fuel temperature threshold, and the oxygen gas heating device (18) is operated if the oxygen gas temperature of the oxygen gas in the oxygen gas supply is below an oxygen gas temperature threshold and / or the combustion chamber temperature is below a combustion chamber temperature threshold.

Description

[0001] The invention relates to a burner system for an exhaust system of an internal combustion engine. The invention further relates to an internal combustion engine with such a burner system, a motor vehicle with such an internal combustion engine, and a method for operating such a burner system.

[0002] The emission limits for internal combustion engines are becoming increasingly stringent. This applies particularly to internal combustion engines intended for powering motor vehicles. To comply with these emission limits, it is essential that the conversion capability of exhaust aftertreatment systems integrated into the exhaust system of such engines is achieved as quickly as possible after a cold start. This requires that the exhaust aftertreatment systems reach their activation temperatures (also known as light-off temperatures) as soon as possible after a cold start, at which point sufficient effectiveness of the exhaust aftertreatment can be assumed.

[0003] It is known to temporarily heat exhaust aftertreatment systems. This can be achieved both through engine-related measures aimed at ensuring that an internal combustion engine produces exhaust gas at a relatively high temperature, and through active heating measures, for example, using electric heating devices or burners. Such a burner can, in particular, use the same fuel intended for operating the internal combustion engine ("fuel").

[0004] At relatively low fuel temperatures due to correspondingly low ambient temperatures, operation and especially ignition of the burner can be problematic. This is particularly true when using diesel fuel for the burner.

[0005] German patent DE 10 2021 104 273 A1 discloses a burner system for a vehicle, comprising a process chamber for mixing and / or burning a fuel, in particular a liquid fuel, with a process gas, in particular air, a fuel supply system directly or indirectly connected to the process chamber for supplying the process chamber with the fuel, and a process gas supply system connected to the process chamber for supplying the process chamber with the process gas, wherein the process gas supply system includes a conditioning device for influencing at least one temperature of the process gas. A comparable burner system is also described in US patent 4,459,805 A.

[0006] DE 11 2008 000 574 T5 discloses a fluid injector for use in an exhaust gas treatment system, comprising an injector body, a closure element arranged in the injector body, wherein the closure element has a fluid receiving end and a fluid injection end, and a heating device arranged around the fluid injection end of the closure element.

[0007] A heated fuel injector for a burner associated with a particulate filter is also described in DE 42 42 091 A1.

[0008] EP 2 617 957 A1 discloses a demand-based heating of an electromagnetic fuel injector of a burner associated with an exhaust stream of an internal combustion engine, wherein the fuel injector is energized to generate heat energy when the fuel supply is interrupted in order to electrically generate waste heat.

[0009] The invention is based on the objective of improving the operation and, in particular, the ignition of a burner system associated with an exhaust stream of an internal combustion engine, especially at relatively low temperatures.

[0010] This problem is solved by the subject matter of the patent claims.

[0011] The invention relates, on the one hand, to a burner system designed and configured to be associated with the exhaust stream of an internal combustion engine. A burner system is essentially a device that combusts fuel with oxygen, particularly as a component of air, within a combustion chamber, thereby generating a hot gas that can be used to directly heat a component. A burner system according to the invention therefore comprises at least one such combustion chamber, a fuel injector for introducing fuel into the combustion chamber, a fuel supply for delivering fuel to the fuel injector, and an oxygen gas supply for delivering oxygen gas (i.e., a gas containing at least oxygen), preferably air or a mixture of air and other gases, in particular exhaust gas from an exhaust gas recirculation system, into the combustion chamber.According to the invention, both the fuel injector and the oxygen gas supply are associated with a fuel heating device.

[0012] An internal combustion engine according to the invention comprises an internal combustion engine having at least one combustion chamber and an exhaust system for removing exhaust gases originating from the at least one combustion chamber. The exhaust gases are at least partially discharged into the environment via the exhaust system. An internal combustion engine according to the invention further comprises a burner system, wherein a hot gas outlet of the combustion chamber opens directly or indirectly into the exhaust system, and a fuel supply system with a fuel tank, wherein the fuel supply connects the fuel tank directly or indirectly to the fuel injector (fuel-carrying).

[0013] A "fuel-carrying" connection is understood to be a connection between two components designed to carry fuel, at least temporarily, from the first component to the second. Preferably, the connection is designed such that this fuel can only flow from the first component to the second (and not in the opposite direction). For this purpose, a suitably designed check valve and / or differential pressure valve can be integrated into such a connection.

[0014] The burner system can preferably be associated with at least one exhaust aftertreatment device integrated into the exhaust stream, such that its operation is designed to heat the exhaust aftertreatment device in a targeted and required manner. Such heating can be provided, in particular, before or immediately after a cold start of the internal combustion engine, when the exhaust aftertreatment device has a temperature below its activation temperature, at which sufficient effectiveness for the intended exhaust aftertreatment can be assumed. However, such heating can also be provided to achieve a temporarily particularly high temperature of the exhaust aftertreatment device with the aim of regenerating it. The exhaust aftertreatment device can, in particular, be a particulate filter.

[0015] A fuel pump can preferably be integrated into the fuel supply of the burner system to ensure demand-based fuel delivery. The fuel pump can preferably be designed as a low-pressure pump capable of providing a maximum delivery pressure of 20 bar, 10 bar, or 6 bar. Such a low-pressure pump can be characterized by correspondingly low power consumption, relatively low manufacturing costs, and a relatively small installation space requirement.

[0016] Furthermore, a gas supply device, particularly in the form of a blower or compressor, can be integrated into the oxygen gas supply to ensure demand-based delivery of the oxygen gas. Additionally, a shut-off valve, particularly in the form of a check valve, can be integrated into the oxygen gas supply to prevent unwanted backflow of gas from the combustion chamber.

[0017] The fuel pump and / or the gas delivery device can / can preferably be driven by an electric motor in order to enable the burner system to operate independently of the operation of the internal combustion engine of the combustion engine.

[0018] A "heating device" is generally understood to be a device primarily or exclusively designed to release heat energy in a controlled manner as needed. Such a heating device (and thus the fuel heating device and / or the oxygen gas heating device) can preferably be electrically operated and therefore based on the conversion of electrical energy into heat energy. Such an electrical heating device can, in particular, be designed as a resistance heating device, although alternative designs for the (electrical) heating device, for example in the form of a piezoelectric heating device or a PTC heating device, can also be advantageously provided. Furthermore, the fuel heating device can be provided with a heating functionality as disclosed in EP 2 617 957 A1.The fuel-fired heating device and / or the oxygen gas heating device may preferably be designed to be controllable or adjustable with regard to heating output. Control or regulation can preferably be implemented electronically. However, simple mechanical control using, for example, a bimetallic switch is also possible.

[0019] A burner system according to the invention enables the implementation of a method according to the invention, characterized in that, upon commissioning of the burner system, the fuel heating device is operated to increase the temperature of the fuel to be introduced into the combustion chamber if the fuel temperature is below a fuel temperature threshold (e.g., any value, optionally variable, between 20°C and 120°C). Furthermore, the oxygen gas heating device is operated to increase the temperature of the oxygen gas to be introduced into the combustion chamber if the oxygen gas temperature of the oxygen gas in the oxygen gas supply is below an oxygen gas temperature threshold (e.g., any value, optionally variable, between 0°C and 50°C) and / or the combustion chamber temperature is below a combustion chamber temperature threshold (e.g., any value, optionally variable, between 200°C and 300°C).The combustion chamber temperature is a temperature specific to the combustion chamber.

[0020] Preferably, the combustion chamber temperature can be the temperature of a gas located inside the combustion chamber.

[0021] By heating both the fuel supplied to the fuel injector via the fuel heating device and the oxygen gas supplied to the combustion chamber via the oxygen gas heating device as needed, safe operation and, in particular, reliable ignition and thus commissioning of the burner system can be ensured even at low temperatures of the fuel and / or oxygen gas and / or the combustion chamber. A particular advantage lies in the fact that the fuel heating device and the oxygen gas heating device can each be selectively activated only when the temperature(s) required for their operation necessitate it. This can have a beneficial effect on the power required for operating the heating devices.It was recognized that low fuel, oxygen gas, and combustion chamber temperatures, which can negatively affect safe operation and, in particular, ignition of the burner system, do not always occur simultaneously. For example, the combustion chamber temperature may still be relatively high despite low ambient temperatures due to a recent combustion operation of the burner system. This means that, in principle, sufficiently reliable ignition and combustion of a fuel-oxygen mixture in the combustion chamber can be ensured even without heating the oxygen gas supplied to the combustion chamber, provided the fuel is sufficiently well atomized and metered accurately by the fuel injector. However, due to the low ambient temperatures, the fuel supplied to the fuel injector may be so cold that sufficiently good atomization and / or metering cannot be guaranteed.The burner system according to the invention makes it possible in such a case to heat only the fuel in order to ensure sufficiently good atomization and / or metering of the fuel, thus enabling an energetically advantageous commissioning of the burner system.

[0022] A further advantage of a burner system according to the invention lies in the fact that, by allowing preheating of both the fuel and the oxygen gas, which has a positive effect on the commissioning of the burner system, the two heating devices—i.e., the fuel heating device and the oxygen gas heating device—can each be designed with relatively low power output. This minimizes or even eliminates the additional costs resulting from the provision of two heating devices. Particularly in this context, it is preferable for the fuel heating device to have a maximum heating output of 100 W, 150 W, or 250 W, and / or for the oxygen gas heating device to have a maximum heating output of 400 W, 500 W, or 600 W.These values ​​may be particularly relevant for a burner system used in an internal combustion engine that is part of a passenger car. For a burner system used in a comparatively larger internal combustion engine (i.e., at least in relation to the (total) volume of the combustion chamber(s)), a higher heating output may be advantageous. In an internal combustion engine that is part of a truck or bus, the maximum heating output of the fuel heating device and / or the oxygen gas heating device may be two to three times the values ​​mentioned above.

[0023] The temperatures considered within the framework of a method according to the invention can each be measured by means of a suitably configured and arranged temperature sensor or determined or calculated using a model.

[0024] According to a preferred embodiment of a method according to the invention, the fuel heating device can be operated in such a way that a target fuel temperature (e.g., any variable value between 20°C and 120°C) is reached and maintained, and the oxygen gas heating device is operated in such a way that a target oxygen gas temperature (e.g., any variable value between 0°C and 50°C) is reached and maintained. This is intended to achieve an effective and simultaneously energy-efficient heating of the fuel and oxygen gas, as heating only occurs to the minimum extent necessary.

[0025] According to a preferred embodiment of a method according to the invention, the fuel temperature threshold and / or the target fuel temperature can be varied depending on the heating potential of the oxygen gas heating device (i.e., the ability to heat the oxygen gas by the oxygen gas heating device, particularly with regard to the maximum achievable fuel temperature). Likewise, the oxygen gas temperature threshold and / or the combustion chamber temperature threshold and / or the target oxygen gas temperature can be varied depending on the heating potential of the fuel heating device (i.e., the ability to heat the fuel by the fuel heating device, particularly with regard to the maximum achievable fuel temperature).In particular, it may be stipulated that a relatively low temperature threshold and / or a relatively high target value is used when the associated heating potential is relatively low. This allows a reduced heating potential of one of the heating devices to be functionally compensated for by an increased heating effect from the other heating device, thereby ensuring continued safe operation and, in particular, reliable ignition of the burner system. In extreme cases, if one of the heating devices fails (malfunctions), this failure can be compensated for by at least a particularly low temperature threshold and / or a particularly high target value for the medium to be heated by the other heating device (the oxygen gas (and thus the combustion chamber) or the fuel).

[0026] It may also be preferably provided that the operation of the fuel heating device and the oxygen gas heating device is reduced or stopped when a combustion chamber temperature target value (e.g. 250°C) is reached.

[0027] Preferably, the fuel used to operate the burner system is the same fuel that is also intended for operating the internal combustion engine. Accordingly, the fuel supply can connect a fuel tank of an internal combustion engine according to the invention directly or indirectly (fuel-carrying) to the fuel injector. The fuel supply can also branch off from a fuel supply system of the internal combustion engine, by means of which the at least one combustion chamber of the internal combustion engine can be supplied with fuel. Such a branch can, for example, originate from a fuel distributor, in which fuel is divided among a plurality of fuel injectors, which, in an internal combustion engine with multiple combustion chambers, are assigned to these multiple combustion chambers.Such a fuel distributor can also serve as a pressure accumulator if the fuel is to be supplied to the fuel injectors at high pressure (e.g., at least 1000 bar). In this case, a pressure relief valve can preferably be integrated into the fuel supply, since it is energetically advantageous to supply the burner system with fuel at low pressure, in particular with a maximum overpressure of 20 bar, 10 bar, or 6 bar (compared to ambient pressure). Furthermore, such an electrically adjustable pressure relief valve advantageously enables the required amount of fuel to be supplied on demand.

[0028] According to a preferred embodiment of a method according to the invention, it can be provided that, after the end of a combustion operation of the burner system (during which hot gas is generated), oxygen gas is passed through the oxygen gas supply and / or fuel through the fuel supply. This can serve to cool the burner system in order to prevent damage or at least a negative impact on the service life of the burner system due to accumulated residual heat energy. The continued passing of oxygen gas through the oxygen gas supply can, in particular, serve to cool the oxygen gas heating device as well as the combustion chamber and the components of the burner system that define it, while passing fuel through the fuel supply can, in particular, serve to cool the fuel injector.The oxygen gas can preferably be discharged via the hot gas outlet of the combustion chamber, which is not usually possible or permissible with regard to the supplied fuel, because it cannot be vented to the environment. Particularly against this background, it can be advantageous if a burner system according to the invention has a fuel discharge line for removing fuel. The fuel discharge line can, in particular, be associated with the fuel injector, so that the fuel discharge line either branches off from the fuel injector itself or branches off from the fuel supply in such a way that a relevant cooling effect is achieved by the fuel flowing through the fuel supply and the fuel discharge line. Preferably, the fuel discharge line branches off from the fuel injector or from the fuel supply line at the shortest possible distance upstream of the fuel injector.

[0029] The fuel discharge can preferably lead into the fuel tank, optionally into the fuel tank of an internal combustion engine according to the invention, in order to realize a fuel cycle that generates a relatively good cooling effect.

[0030] Cooling the burner system after a combustion operation has ended can, for example, be carried out for a defined period and / or controlled, and in particular also terminated, depending on a temperature of the burner system that can be measured and / or modeled.

[0031] The internal combustion engine of an internal combustion engine according to the invention can, in particular, be a (self-igniting and quality-controlled) diesel engine, because relatively low temperatures, especially with diesel fuel, which is preferably also used as fuel for the burner system, can negatively affect its properties, particularly with regard to atomizability. However, it is also possible that the internal combustion engine is a (spark-ignition and quantity-controlled) gasoline engine or a functional combination of a diesel and a gasoline engine, e.g., an internal combustion engine with homogeneous compression ignition. The internal combustion engine can, in particular, be operated with liquid fuel (i.e., diesel or gasoline).

[0032] The invention also relates to a motor vehicle, in particular a land vehicle, especially preferably a wheeled and not rail-bound motor vehicle (preferably a passenger car, a truck, or a bus), with an internal combustion engine according to the invention. (Note: for a potential distinction from prior art, e.g., diesel-powered locomotives or ships or stationary power plants (is sometimes cited as an alternative).) The internal combustion engine of the motor vehicle can be provided, in particular, for the (direct or indirect) provision of the propulsion power for the motor vehicle.

[0033] The invention is explained in more detail below with reference to an embodiment illustrated in a drawing. The drawing shows: Fig. 1: according to the burner system in simplified representation.

[0034] The one in Fig.The burner system 1 shown comprises a burner 2, which defines a combustion chamber 3. A hot gas outlet 4 of the combustion chamber 3 leads into an exhaust stream 5 of an internal combustion engine comprising the burner system 1, which is not shown in further detail.

[0035] The burner system 1 further comprises a fuel injector 6, which is schematically depicted as an electromagnetically actuated switching valve (an implementation as a proportional valve is also possible). Fuel can be introduced into the combustion chamber 3 by means of the fuel injector 6, controlled by a control device 12 of the internal combustion engine. Fuel quantity control can be achieved by corresponding timing of the switching of the fuel injector 6, which functions as a switching valve. The fuel can be supplied to the fuel injector 6 from a fuel tank 7, which can preferably also be a fuel tank of the internal combustion engine, via a fuel supply 8. An electrically driven fuel pump 9 is integrated into the fuel supply 8 to deliver the fuel.The fuel pump 9 also sets a defined fuel pressure in the fuel injector 6, whereby for setting and in particular regulating the fuel pressure a measurement of the relevant actual value is carried out by means of a fuel pressure sensor 10, which is integrated into the fuel supply 8 between the fuel pump 9 and the fuel injector 6.

[0036] A fuel line 11 branches off from the fuel supply 8 at the shortest possible distance upstream of the fuel injector 6. The fuel line 11, which incorporates an actively adjustable pressure relief valve 13 via the control device 12, leads into the fuel tank 7 and allows fuel supplied via the fuel supply 8 to be partially or completely returned to the fuel tank 7. The pressure relief valve 13 enables fine control of the fuel pressure, which is generally set by the fuel pump 9. Specifically, the pressure relief valve 13 opens slightly during periods of overpressure due to the uneven fuel pressure generated by the fuel pump 9, thereby returning small amounts of fuel to the fuel tank 7.

[0037] An electrically operated fuel heating device 14, controllable by means of the control device 12, is integrated into the fuel injector 6. By operating the fuel heating device 14, the fuel injector 6, and thus also the fuel contained therein, can be heated as required. According to the invention, this is provided at least for the commissioning of the burner system 1 when the fuel temperature is lower than a defined fuel temperature threshold. This is intended to achieve the finest possible atomization of the fuel and thus a uniform distribution of the fuel in the combustion chamber 3 via the fuel injector 6, which is advantageous with regard to the ignition of the burner system 1 and / or a fuel-oxygen mixture within the combustion chamber 3.

[0038] The oxygen for forming the fuel-oxygen mixture within the combustion chamber 3 is supplied via an oxygen gas supply 15 of the burner system 1. This supply can preferably branch off from a fresh gas stream (not shown) of the internal combustion engine, particularly downstream of an integrated air filter. Integrated into the oxygen gas supply 15 is an electrically driven gas delivery device 16, controllable by means of the control device 12, for delivering the oxygen gas (in this case, air), a check valve 17, which, when the gas delivery device 16 is deactivated, prevents gas from flowing back from the combustion chamber 3 into the fresh gas stream of the internal combustion engine, and an electrically operated oxygen gas heating device 18, also controllable by means of the control device 12.Alternatively or in addition to the check valve 17, any other, in particular actively controllable, closure element, for example an actively controllable closure flap, may also be provided.

[0039] Operating the oxygen gas heating device 18 can heat the oxygen gas, which also results in an increase in the combustion chamber temperature. This can also be advantageous with regard to ignition and, in general, combustion of a fuel-oxygen mixture within the combustion chamber 3. This applies at least when the temperature of the oxygen gas (oxygen gas temperature) is lower than an oxygen gas temperature threshold and / or the burner itself and, in particular, the atmosphere within the combustion chamber 3 are still relatively cold or lower than a defined combustion chamber temperature threshold.

[0040] When burner system 1 is commissioned, the following can be determined before the first fuel is introduced into the combustion chamber 3: a fuel temperature using a fuel temperature sensor 19 integrated into the fuel supply 8, an oxygen gas temperature using an oxygen gas temperature sensor 20 integrated into the oxygen gas supply 15, and a combustion chamber temperature using a combustion chamber temperature sensor 21. If the determined oxygen gas temperature is below the defined oxygen gas temperature threshold and / or the combustion chamber temperature is below the combustion chamber temperature threshold, the oxygen gas heating device 18 is activated, thus heating the oxygen gas supplied via the oxygen gas supply 15 for operation of burner system 1, ideally until a target oxygen gas temperature is reached.If, on the other hand, the oxygen gas temperature or the combustion chamber temperature corresponds at least to the respective threshold value, the oxygen gas heating device 18 is not operated, because then safe ignition and combustion of a fuel-oxygen mixture within the combustion chamber 3 can be ensured even without heating the oxygen gas by means of the oxygen gas heating device.

[0041] The fuel heating device 14 is activated when the burner system 1 is started up if the measured fuel temperature is below the defined fuel temperature threshold. Conversely, the fuel heating device 14 is not activated if the fuel temperature threshold has at least been reached. When the fuel heating device 14 is operating, the fuel inside the fuel injector 6 is heated to a target fuel temperature.Although a sufficiently high combustion chamber temperature can already ensure reliable ignition and combustion of a fuel-oxygen mixture within the combustion chamber, the fuel heating device 14 can be started up independently of the combustion chamber temperature, and thus also when the combustion chamber temperature threshold has at least been reached, because excessively cold fuel can make it difficult or even impossible to generate a defined fuel-oxygen mixture within the combustion chamber 3. This is because excessively cold fuel cannot be metered precisely enough or atomized finely enough by the fuel injector 6.

[0042] The operation of the oxygen gas heating device 18 can be terminated during combustion of the burner system 1 as soon as the combustion chamber temperature reaches the combustion chamber temperature threshold. The same applies to the operation of the fuel heating device 14, whereby an additional requirement for terminating the operation of the fuel heating device 14 may be that the combustion chamber temperature threshold has been reached or exceeded for a defined minimum period. This ensures that the fuel injector 6, even without heat energy released by the fuel heating device 14 and consequently essentially exclusively by the waste heat of the burner 2, has been and will continue to be heated sufficiently to maintain a fuel temperature at least corresponding to the fuel temperature threshold throughout the continued combustion operation of the burner system 1.

[0043] After the combustion operation of burner system 1 has ended, oxygen gas may continue to be supplied via the oxygen gas supply 15 and introduced into the combustion chamber 3 to cool the oxygen gas heating device 18 and also the burner 2. The oxygen gas, heated by a cooling heat transfer, is discharged into the exhaust gas stream 5 via the hot gas outlet 4 of the combustion chamber 3. Such a supply of oxygen gas after a combustion operation of burner system 1 may be particularly useful if the oxygen gas heating device 18 was operated until the end of the combustion operation, because then a considerable amount of residual heat energy is still provided by the oxygen gas heating device 18.

[0044] Furthermore, after the combustion operation of burner system 1 has ended, it may be provided that fuel is still supplied via the fuel feed 8 to cool the fuel injector 6. This fuel is then completely discharged via the fuel outlet 11. The pressure relief valve 13 can be opened to minimize the pressure drop across it, thus requiring the lowest possible drive power from the fuel pump to deliver the fuel. Reference symbol list 1 burner system 2 burners 3 Combustion chamber 4 Hot gas outlet 5 Exhaust system 6 Fuel injector 7 Fuel tank 8 Fuel supply 9 Fuel pump 10 Fuel pressure sensor 11 Fuel drainage 12 Control device 13 Pressure relief valve 14 Fuel heating device 15 Oxygen gas supply 16 Gas conveying device 17 Check valve 18 Oxygen gas heating device 19 Fuel temperature sensor 20 Oxygen gas temperature sensor 21 Combustion chamber temperature sensor QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 104 273 A1

[0005] US 4 459 805 A

[0005] DE 11 2008 000 574 T5

[0006] DE 42 42 091 A1

[0007] EP 2 617 957 A1 [0008, 0018]

Claims

[1] Burner system (1) for an exhaust stream (5) of an internal combustion engine, comprising a combustion chamber (3), a fuel injector (6) for introducing fuel into the combustion chamber (3), a fuel supply (8) for supplying fuel to the fuel injector (6) and an oxygen gas supply (15) for supplying oxygen gas to the combustion chamber (3), characterized by , that a fuel heating device (14) is associated with the fuel injector (6) and an oxygen gas heating device (18) is associated with the oxygen gas supply (15). [2] Burner system (1) according to claim 1, characterized by , that the fuel heating device (14) and / or the oxygen gas heating device (18) is / are designed to be electrically actuated. [3] Burner system (1) according to claim 1 or 2, characterized by, that the fuel heating device (14) has a maximum heating power of 100 W or 150°W or 250°W and / or the oxygen gas heating device (18) has a maximum heating power of 400 W or 500° or 600°W. [4] Burner system (1) according to any one of the preceding claims, characterized by a fuel outlet (11) associated with the fuel injector (6) for draining fuel. [5] Internal combustion engine with • an internal combustion engine that forms at least one combustion chamber, • an exhaust system (5) for discharging exhaust gas originating from the at least one combustion chamber, • a burner system (1) according to one of the preceding claims, wherein a hot gas outlet (4) of the combustion chamber (3) opens into the exhaust gas stream (5), and • a fuel supply system with a fuel tank (7), wherein the fuel supply (8) connects the fuel tank (7) to the fuel injector (6). [6] Method for operating a burner system (1) according to any one of claims 1 to 4, characterized by , that when the burner system (1) is put into operation, the fuel heating device (14) is operated when the fuel temperature is less than a fuel temperature threshold, and the oxygen gas heating device (18) is operated when the oxygen gas temperature of the oxygen gas in the oxygen gas supply is less than an oxygen gas temperature threshold and / or the combustion chamber temperature is less than a combustion chamber temperature threshold. [7] Method according to claim 6, characterized by , that the fuel heating device (14) is operated in such a way that a fuel temperature target value is reached and maintained, and the oxygen gas heating device (18) is operated in such a way that an oxygen gas temperature target value is reached and maintained. [8] Method according to claim 6 or 7, characterized by, that the fuel temperature threshold and / or the fuel temperature target value is varied depending on the heating potential of the oxygen gas heating device (18) and / or the oxygen gas temperature threshold and / or the combustion chamber temperature threshold and / or the oxygen gas temperature target value is varied depending on the heating potential of the fuel heating device (14). [9] Method according to any one of claims 6 to 8, characterized by , that the operation of the fuel heating device (14) and the oxygen gas heating device (18) is reduced or stopped when a combustion chamber temperature target value is reached. [10] Method according to any one of claims 6 to 9, characterized by , that after the combustion operation of the combustion system (1) has ended, oxygen gas is supplied via the oxygen gas supply (15) and / or fuel is supplied via the fuel supply (8).

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