Exhaust Heater

Abstract

The invention relates to an exhaust gas heater for an exhaust gas system of an internal combustion engine, comprising a heat conductor (12), which comprises a first supply voltage connection (28), a second supply voltage connection (32) and a heating region (38) extending between the first supply voltage connection (28) and the second supply voltage connection (32), the exhaust gas heater also comprising a voltage measuring section (42) integrated into the heating region (38).

Description

Technical Field

[0001] The invention relates to an exhaust gas heater for an exhaust gas system of an internal combustion engine, an exhaust gas heating system constructed with such an exhaust gas heater and an exhaust gas system comprising such an exhaust gas heater or exhaust gas heating system. The invention further relates to a method for operating such an exhaust gas heater. Background Art

[0002] From the German patent application DE 10 2020 123 376, which was published later, an exhaust gas heater is known, which has a heat conductor, which comprises a heating region extending between two supply voltage connections and through which exhaust gas can flow in an exhaust gas system. The heat conductor of the exhaust gas heater is provided by being cut out of a metallic flat material. By applying a voltage between the supply voltage connections and by a current flowing between the supply voltage connections when the voltage is applied, heat is generated based on a heating power that is essentially defined by the product of the voltage and the current, which heat is at least partially transferred to the exhaust gas flowing around the heat conductor or its heating region. Summary of the invention

[0003] The object of the present invention is to provide an exhaust gas heater and a method for operating an exhaust gas heater, with which an improved adaptability of the heating operation to ambient conditions, for example the temperature of the exhaust gas circulating through a heating conductor, can be achieved.

[0004] According to the invention, this object is achieved by an exhaust gas heater for an exhaust gas system of an internal combustion engine. The exhaust gas heater has a heat conductor, which comprises a first supply voltage connection, a second supply voltage connection and a heating region extending between the first supply voltage connection and the second supply voltage connection, and further has a voltage measuring section integrated into the heating region.

[0005] By providing such a voltage measuring section on the heat conductor or the heating region of the heat conductor, it is possible to determine the temperature in the region of the voltage measuring section and thus also the temperature of the heating region by measuring or detecting the voltage drop on the voltage measuring section based on the generally known relationship between the voltage and the resistance of the voltage measuring section and the generally known relationship between the resistance and the temperature, which temperatures can in principle be assumed to also correspond substantially to the temperature of the voltage measuring section. Thus, information about the temperature of the heat conductor in the region of the heating region of the heat conductor in which the exhaust gas circulates or can circulate can be provided. Thus, it is possible to set the temperature of the heat conductor in a desired range or to keep it in the range of a setpoint value by changing the supply voltage and thereby also changing the heating power generated on the heat conductor.

[0006] In a particularly simple and realizable embodiment, the voltage measuring section can have a section of the heating region. This means that the measurement voltage is tapped directly at the heating region or between two voltage measuring connections provided at the heating region and can therefore directly provide information about the temperature of the heating region in the longitudinal section of the heating region that provides the voltage measuring section.

[0007] In an alternative design, the voltage measuring section can have a measuring resistor, wherein a first connection area of ​​the measuring resistor is connected to a first heating region section leading to a first supply voltage connection and a second connection area of ​​the measuring resistor is connected to a second heating region section leading to a second supply voltage connection, wherein the measuring resistor is electrically connected in series with the first heating region section and the second heating region section. In this design, the thermal conductor is interrupted in the region of the voltage measuring section, so that there are two heating region sections of the heating region that are physically separated from one another by the voltage measuring section, but are electrically conductively connected to one another by the voltage measuring section. Integrating such a measuring section in the form of a measuring resistor implemented as a separate component into the thermal conductor or its heating region provides the possibility of using a material for the measuring resistor that enables an accurate detection of the measuring voltage or resistance and therefore also an accurate determination of the temperature prevailing in the region of the measuring section in the operating temperature range to be considered, i.e., the temperature range in which such an exhaust gas heater is usually operated.

[0008] In another alternative design, the measuring section integrated into the heating region can have a measuring resistor extending along a section of the heating region. In this design as well, it is possible to use a particularly suitable material for the measuring resistor without interrupting the heat conductor or the heating region and thus not being able to use its longitudinal section for thermal interaction with the exhaust gas.

[0009] In order to be able to use the measuring resistor particularly effectively for detecting the voltage drop, it is proposed that in the case of a measuring resistor which is electrically connected in series with the first heating area segment and the second heating area segment, a first voltage measuring connection on the measuring resistor is formed in the region of the first connection area and a second voltage measuring connection on the measuring resistor is formed in the region of the second connection area.

[0010] In the case of a measuring resistor extending along a section of the heating region, the measuring resistor can be in thermal contact with the heating region substantially over its entire length region extending between the first voltage measuring connection and the second voltage measuring connection. This ensures that the measuring resistor, due to its thermal contact with the heating region, has a temperature that corresponds to the temperature of the heating region.

[0011] For increased accuracy in detecting the voltage drop between the voltage measuring terminals, the voltage measuring section can have a resistance characteristic that differs from the resistance characteristic of the heating region. This makes it possible, in particular, to use a structural material for the heating conductor or its heating region that has only a relatively low dependence of resistance on temperature in the temperature range in which such an exhaust gas heater or its heating conductor is usually operated.

[0012] In such an operating temperature range, the voltage measuring section can advantageously have a resistance that changes more strongly in a temperature-dependent manner than the heating region. This means that the magnitude of the gradient of the resistance-temperature relationship is greater in the voltage measuring section than in the thermal conductor. Alternatively or additionally, such different resistance characteristics can be provided so that in the operating temperature range, the voltage measuring section has a smaller resistance than the heating region. This ensures that, due to the smaller resistance, a smaller voltage drop and correspondingly also a smaller heating power occur in the measuring section compared to the heating region, so that the temperature of the measuring section can be determined primarily by the temperature of the heating region that is in heat transfer contact with the measuring section.

[0013] In a particularly advantageous design with a strong temperature dependence of the resistance, the voltage measuring section can have a PTC resistance characteristic or an NTC resistance characteristic. Such a resistance characteristic is characterized in that, unlike, for example, in metals, the resistance characteristic has an exponential relationship between temperature and resistance in a temperature range that is particularly relevant for the operation of the exhaust gas heater, rather than a linear relationship. This means that relatively small temperature changes already cause a strong change in the resistance that can be detected by measuring the voltage. The use of a structural material with a PTC resistance characteristic provides another advantage, especially when the voltage measuring section is connected in series to the thermal conductor, namely, with an exponential increase in resistance, a self-regulating effect of the heating power and thus overheating protection for the thermal conductor can be provided at relatively high temperatures.

[0014] The invention further relates to an exhaust gas heating system for an exhaust gas system of an internal combustion engine, comprising at least one exhaust gas heater having a construction according to the invention through which exhaust gas can flow, and an actuation arrangement for detecting a measurement voltage between a first voltage measuring connection and a second voltage measuring connection and for applying a supply voltage between a first supply voltage connection and a second supply voltage connection as a function of the detected measurement voltage.

[0015] The control arrangement can be designed to apply the supply voltage to be applied between the first supply voltage terminal and the second supply voltage terminal as a function of the detected measurement voltage and the setpoint measurement voltage or setpoint temperature in the region of the measurement section. That is, a voltage regulation can be provided, which is used to ensure that the temperature of the measurement section determined based on the detected measurement voltage, that is, the actual voltage, is in the range of the setpoint temperature or fluctuates around the setpoint temperature (around the setpoint temperature) as a function of the control strategy and therefore deviates from the setpoint temperature only to an extent that is essentially dependent on the set control strategy. The setpoint temperature or the setpoint measurement voltage corresponding to the determined setpoint temperature can be predetermined, for example, as a function of environmental parameters, for example, the exhaust gas temperature of the exhaust gas flowing through the exhaust gas heater.

[0016] The invention further relates to an exhaust gas system for an internal combustion engine having an exhaust gas heating system with at least one exhaust gas heater designed according to the invention.

[0017] The object specified at the outset is further achieved by a method for operating an exhaust gas heater designed according to the invention, preferably in an exhaust gas heating system comprising at least one exhaust gas heater designed according to the invention or in an exhaust gas system comprising such an exhaust gas heating system, the method comprising the measures:

[0018] a) applying a supply voltage between the first supply voltage connection and the second supply voltage connection,

[0019] b) detecting a measurement voltage between the first voltage measuring connection and the second voltage measuring connection,

[0020] c1) comparing the measured voltage detected in measure b) with a setpoint measured voltage in order to determine a voltage deviation between the detected measured voltage and the setpoint measured voltage and regulating the supply voltage as a function of the voltage deviation such that the detected measured voltage lies in the range of the setpoint measured voltage,

[0021] or

[0022] c2) Comparing the temperature determined based on the measured voltage detected in measure b) with a desired temperature to determine a temperature deviation between the determined temperature and the desired temperature and regulating the supply voltage as a function of the temperature deviation so that the determined temperature is within the range of the desired temperature.

[0023] It should be noted that the detection of the measurement voltage forms the basis for determining the resistance of the measurement section and thus the temperature of the measurement section, based on the relationship between the detected measurement voltage and the resistance of the measurement section or the temperature of the measurement section. The regulation or adjustment of the measurement voltage thus leads to the regulation or adjustment of the resistance and thus the temperature of the measurement section and thereby also the temperature of the thermal conductor.

[0024] In measure c2), the temperature in the region of the measuring path can be determined using a measured voltage-temperature relationship. This relationship can be stored, for example, in the form of a characteristic curve set or a functional relationship, so that for each value of the measured voltage assigned to it, by reading from the characteristic curve set or by calculation using the functional relationship, the temperature represented by the corresponding measured voltage can be determined and, if necessary, compared with a setpoint temperature.

[0025] The setpoint temperature or the setpoint measurement voltage representing the setpoint temperature may preferably be predefined as a function of environmental parameters, for example the temperature of the exhaust gas flowing through the exhaust gas heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Next, the present invention will be described in detail with reference to the accompanying drawings.

[0027] Figure 1 An exhaust gas heater is shown which comprises a heat conductor supported on a support arrangement and a voltage measuring section integrated into the heat conductor;

[0028] Figure 2 The exhaust heater corresponds to Figure 1 , showing two different alternative designs of a voltage measuring section integrated into a thermal conductor;

[0029] Figure 3 shows the relationship between the temperature and the resistance of a thermal conductor and the measured resistance of a voltage measuring section having a PTC resistance characteristic;

[0030] Figure 4 Shown included in Figure 2 A side view of the hot conductor of the voltage measurement section is shown in the left half;

[0031] Figure 5 Shown included in Figure 2 The right half shows a side view of the hot conductor of the voltage measurement section;

[0032] Figure 6 The schematic diagram of an exhaust gas system includes an exhaust gas heater and a voltage measuring section integrated into the exhaust gas heater. DETAILED DESCRIPTION

[0033] exist Figure 11 shows an exhaust gas heater 10, as described in its basic design, for example, in the German patent application DE 10 2020 123 376 published later. The exhaust gas heater 10 has, for example, a heat conductor 12 formed by separation from a metal sheet, which is designed in the illustrated design with six meandering sections 14, 16, 18, 20, 22, 24 that are arranged one after another in the circumferential direction around a central region. In each of the meandering sections 14, 16, 18, 20, 22, 24, the respective meandering sections are arranged radially stepped relative to one another and are connected to the respectively following meandering section in the radial direction in one of its circumferential end regions.

[0034] On the meandering zone 12, the radially outermost meandering section 26 provides a first supply voltage connection 28 in one of its circumferential end regions. Correspondingly, the radially outermost meandering section 30 of the meandering zone 24 provides a second supply voltage connection 32 in one of its circumferential end regions. Respective voltage supply lines 34, 36 can be connected to the two supply voltage connections 28, 32, which can be guided through an exhaust gas-tight guide passage in an exhaust gas guide element, for example tubular, containing the exhaust gas heater 10.

[0035] Between the two supply voltage connections 28 , 30 , the heating conductor 12 has a heating region, generally designated 38 , which, when a voltage is applied to the supply voltage connections 28 , 30 , heats up due to the current flowing therein and can thus transfer heat to the exhaust gas circulating around the heating region 38 .

[0036] The heating conductor 12 or its heating region 38 is supported on a support arrangement 40 which can have, for example, a respective carrier disk on the upstream and downstream side of the heating conductor 12 , which is connected radially on the outside to a, for example, tubular exhaust gas guide element.

[0037] It should be noted that the structure or course of the heating region 38 including the meandering regions 14, 16, 18, 20, 22, 24 is merely exemplary. The heating region can also have another structure, for example a spiral (helical) course.

[0038] A measuring section, generally designated 42, is integrated into the heating region 38 of the heat conductor 12. The measuring section 42 is Figure 1, has a measuring resistor 44 which is connected in a first connection region 46 to a first heating region segment 48 leading to a first supply voltage connection 28, for example by screwing, riveting, soldering, welding, etc., and in a second connection region 50 is connected in the same manner to a second heating region segment 52 leading to a second supply voltage connection 32. The heating region 38 is thus designed with its two heating region segments 48, 50 as two segments which are physically separated from one another in principle, but which are electrically conductively connected to one another via the measuring resistor 44 which is connected to the segments and is therefore electrically connected in series with them.

[0039] In the region of the first connection region 46, a first voltage measuring connection 54 is provided, to which a first voltage measuring line 56 is connected. Likewise, in the region of the second connection region 50, a second voltage measuring connection 58 is provided, to which a second voltage measuring line 60 is connected. The voltage measuring lines 56, 60 can also be guided through the exhaust gas guide element via a guide passage of the exhaust gas seal.

[0040] The measuring resistor 44 of the voltage measuring section 42 preferably has a resistance characteristic that is different from the resistance characteristic of the heat conductor 12. The heat conductor 12 is formed, for example, using a metallic material, which in principle has a relatively low resistance and has an approximately constant and only slightly increasing resistance in the temperature range in which the exhaust gas heater 10 is to be operated, that is, up to a temperature of approximately 700° C. to 800° C. The measuring resistor 44 can be, for example, a PTC element with a PTC resistance characteristic. The resistance characteristics of the heat conductor 12 and the measuring resistor 44 formed as a PTC element are Figure 3 The curve K1 shows the resistance of the heat conductor 12, which changes only slightly in a relatively large temperature range. The curve K2 shows the PTC resistance characteristic of the measuring resistor 44 in principle. The PTC resistance characteristic is characterized in that it shows a significantly lower resistance than, for example, the heat conductor 12 in a large temperature range, especially in a temperature range relevant for the normal operation of the exhaust gas heater 10, but has a strong dependence of the resistance on the temperature. As the temperature increases, the resistance of the measuring resistor 44 increases exponentially and therefore also exceeds the resistance of the heat conductor 12.

[0041] Various advantages are achieved by using such a temperature-resistance characteristic of the heat conductor 12 on the one hand and the measuring resistor 44 on the other hand. On the one hand, due to the relatively low resistance of the measuring resistor (impedance) 44 or the measuring section 42 in the temperature range in which the exhaust gas heater 10 is usually operated, only a relatively small voltage drop and therefore also a relatively small heating power occurs in the measuring resistor 44 connected in series with the two heating area sections 48, 52. The measuring resistor 44 therefore generates relatively little heat itself, so that its temperature is essentially determined by the temperature of the heat conductor 12 or the two heating area sections 48, 52 physically connected to the measuring resistor 44. On the other hand, the resistance of the measuring resistor 44 changes relatively strongly with temperature, so that relatively small temperature changes already lead to a significant change in the resistance and therefore the voltage drop across the measuring resistor 44. This voltage drop can be detected as a measurement voltage on the voltage measuring wires 56, 60 and thus provides a direct conclusion about the temperature of the measuring resistor 44 and therefore also the temperature of the heating area 38 connected to the measuring resistor.

[0042] Another advantage of the PTC resistance characteristic of the measuring resistor 44 is that the resistance of the measuring resistor 44 also increases strongly when the temperature rises too strongly. The strongly increased resistance of the measuring resistor 44 is due to the connection of the measuring resistor 44 to the two heating area sections 48, 52 in series, resulting in a relatively small current flowing through it, which also causes the heating power of the entire exhaust gas heater 10 to be suppressed when the temperature rises too strongly. That is, a self-regulating effect can be achieved by using this resistance characteristic, which makes the heating power correspondingly reduced based on the strongly increased resistance with the rising temperature. For example, it can be achieved by selecting the structural material of the measuring resistor 44 that in the operating temperature range of up to about 700°C to 800°C, when the temperature in the area of ​​the measuring section 42 further rises, such a strong increase in the resistance of the measuring resistor 44 occurs, so that the heating power of the exhaust gas heater 10 is only very small at a temperature of about 900°C, for example, almost zero.

[0043] Figure 6 An exhaust system for an internal combustion engine, for example in a motor vehicle, is illustrated schematically and is generally designated by 62. The exhaust system 62 has a tubular exhaust gas guiding element 64, in which the exhaust gas A flows toward the exhaust gas heater 10 arranged in the exhaust gas guiding element 44. The supply voltage connections 28, 32 of the exhaust gas heater are connected to an actuation arrangement 66 via supply lines 34, 36, so that a supply voltage can be applied to the supply voltage connections 28, 32 of the heat conductor 12 via the actuation arrangement 66, for example based on the vehicle voltage present in the vehicle.

[0044] The voltage measuring connections 54, 58 or the voltage measuring lines 56, 60 leading away therefrom are also connected to the control arrangement 66, so that the voltage drop across the measuring resistor 44 can be detected in the control arrangement 66. By means of the voltage drop between the two voltage measuring connections 54, 58, i.e. the relationship between the measured voltage detected across the measuring resistor 44 and the resistance of the measuring resistor 44 or the temperature represented by the resistance of the measuring resistor 44 in the region of the measuring resistor 44 or the measuring intensity 42, which is stored in the control arrangement 66, for example in the form of a characteristic curve or a functional relationship, it is thus possible to provide information about this temperature or the temperature in the region of the heating region 38 of the heating conductor 12 as a whole.

[0045] The control arrangement 66 can be designed to regulate or adjust the temperature of the heating region 38 or the exhaust gas heater 10 to a desired temperature, for example, which is dependent on the exhaust gas temperature. This can be done, for example, by determining the actual temperature in the region of the measuring resistor 44 and comparing it with the desired temperature based on the measured voltage detected at the measuring resistor 44 and the known relationship between the measured voltage and the resistance of the measuring resistor 44 and thus the temperature in the region of the measuring resistor 44. Depending on the deviation between the actual temperature and the desired temperature, the supply voltage applied to the supply voltage terminals 28, 32 can then be changed in order to thereby achieve, during the control process, that the actual temperature is in the range of the desired temperature.

[0046] However, since there is a direct relationship between the voltage drop across the measuring resistor 44, that is to say the measuring voltage, and the resistance of the measuring resistor 44 and thus also the temperature in the region of the measuring resistor 44, it is not absolutely necessary to convert the measuring voltage into a temperature. Instead, a setpoint measuring voltage can also be predetermined in the control arrangement 46, which can be varied, for example, as a function of the exhaust gas temperature. This setpoint measuring voltage can be compared with the measuring voltage detected across the measuring resistor 44, that is to say the actual measuring voltage, so that then also the supply voltage applied to the supply voltage terminals 28, 32 can be varied as a function of the value between the setpoint measuring voltage and the actual measuring voltage, so that the exhaust gas heater 10 can be operated with a heating power that is optimized, for example, for the respectively existing exhaust gas temperature or, for example, in the region of an exhaust gas treatment unit 68, for example a catalytic converter arrangement, which follows the exhaust gas heater 10 in the direction of the exhaust gas flow.

[0047] It is further pointed out that the predetermined rated measuring voltage or the predetermined rated measuring temperature is synonymous with the rated resistance predetermined for the measuring resistor 44. Based on the measuring voltage, the resistance of the measuring resistor 44 can be adjusted based on the generally known relationship between the voltage drop at the measuring resistor 44 and its resistance by changing the supply voltage at the supply voltage terminals 28, 32 so that the resistance corresponds to the rated resistance. Since the measuring voltage, the resistance of the measuring resistor 44 and the temperature in the region of the measuring resistor 44 are physical variables that correspond to each other or are in a clear (uniquely corresponding) relationship with each other, each of the variables can be considered as a basis for temperature detection or temperature regulation, or the use of one of the variables as a regulating variable also means that other variables that are clearly associated with the variables form the basis for regulating or adjusting the temperature of the exhaust gas heater 10 (open-loop control or closed-loop control).

[0048] exist Figure 2 In FIG. 1 , an alternative design of an exhaust gas heater 10 is shown, which in particular comprises two alternatively designed measuring sections 42 ′ and 42 ″. Figure 4 The measuring section 42 is graphically illustrated in FIG. Figure 2 In the design shown on the left in FIG. 1 , the measuring section has a measuring resistor 44 ′ which is not individually (physically) installed in the heating region 38 of the thermal conductor 12, but rather has a measuring resistor 44 which extends along a section 70 of the heating region 38 and is electrically insulated from the heating region 38 by an insulating material 72. However, the measuring resistor 44 ′ is in heat-conducting contact with the heating region 38 of the thermal conductor 12 by means of the electrically insulating insulating material 72. The insulating material 72 can be, for example, a temperature-resistant adhesive or can also contain a soldering material or a welding material in the measuring resistor 44 ′ contained in the insulating encapsulation.

[0049] Voltage measuring connections 54, 58 are formed at both ends of the measuring resistor 44', to which voltage measuring lines 56, 60 are connected. The voltage drop occurring across the measuring resistor 44', i.e. the measuring voltage, can be detected via the voltage measuring lines 56, 60, which in turn has a clear (uniquely assigned) relationship to the temperature of the measuring resistor 44'. For example, in such a design, the measuring resistor can be designed as a so-called Pt100 platinum resistor, which has a substantially linear, but significant increase in resistance with temperature, especially in a temperature range of up to approximately 800°C.

[0050] By integrating the measuring section 42 ′ into the heat conductor 12 in such a way that it is in thermal contact with the heat conductor but has no electrically conductive interaction therewith, the heat conductor 12 or its heating region 38 is available over essentially the entire longitudinal section for heat transfer to the exhaust gas A flowing around it.

[0051] It should be pointed out that, of course, Figure 4 In the design shown in FIG. 1 , the measuring resistor 44 ′ of the measuring section 42 ′ can also have another resistance characteristic, for example, Figure 1 The PTC resistance characteristic described in the design of . However, since there is no electrical interaction between the measuring resistor 44' and the thermal conductor 12 in this design, it is not possible to use the self-regulating effect based on the greatly increased resistance in the PTC element. However, the temperature of the thermal conductor 12 can be prevented from exceeding the upper threshold temperature by corresponding regulating measures by means of the control arrangement 66 based on monitoring of the temperature in the region of the measuring section 42'.

[0052] In the exhaust heater 10 Figure 2 in the right and in Figure 5 In the embodiment illustrated in FIG. 1 , the measuring section 42 ″ has a section 74 of the heating region 38 of the heat conductor 12 . The voltage measuring connections 54 , 58 are formed at the heating region 38 , for example, by soldering or welding the voltage measuring wires 56 , 60 . Figure 3 As is illustrated in the figure, the heating region 38 also has a resistance that changes with temperature, so that the resistance of the section 74 and thus its temperature can be inferred by detecting the voltage drop, that is to say the measured voltage, between the two voltage measuring connections 54, 58. Since the voltage drop occurring between the voltage measuring connections 54, 58 depends on the resistance of the section 74 and the resistance of the section 74 depends on its length, it can be advantageous to arrange the voltage measuring connections 54, 58 as far apart from each other as possible along the heating region 38 for the most accurate detection of the measured voltage or the change in the measured voltage. For example, the voltage measuring connections can also be arranged in the region of the supply voltage connections 28, 32.

[0053] The configuration according to the invention of the exhaust gas heater enables the possibility of monitoring the temperature in the region of the exhaust gas heater or its heat conductor and regulating or adjusting the temperature to a value that is particularly favorable for the corresponding operation of the internal combustion engine and therefore in particular also for the exhaust gas temperature or also for the temperature of the exhaust gas treatment unit following downstream. Different types of measuring sections can be used for this purpose. If the measuring section has a measuring resistor provided as a separate component, the measuring resistor can be constructed with different resistance characteristics. The PTC resistance characteristic is particularly advantageous because it brings about a self-regulating effect of the heating power or temperature of the exhaust gas heater 10 when the temperature rises excessively. However, it is also possible to use a measuring resistor with other resistance characteristics, such as an NTC resistance characteristic or a substantially linear resistance characteristic as is usually present in metals.

Claims

1. An exhaust gas heater for an exhaust gas system of an internal combustion engine, the exhaust gas heater having a heat conductor (12), the heat conductor comprising a first supply voltage connection (28), a second supply voltage connection (32) and a heating region (38) extending between the first supply voltage connection (28) and the second supply voltage connection (32), the exhaust gas heater further comprising a voltage measuring section (42) integrated into the heating region (38), the voltage measuring section (42) comprising a measuring resistor (44), a first connection region (46) of the measuring resistor (44) being connected to a first heating region section (48) leading to the first supply voltage connection (28) and a second connection region (50) of the measuring resistor (44) being connected to a second heating region section (52) leading to the second supply voltage connection (32), the measuring resistor (44) being electrically connected in series with the first heating region section (48) and the second heating region section (52).

2. The exhaust gas heater according to claim 1, characterized in that: A first voltage measuring connection (54) on the measuring resistor (44) is formed in the region of the first connection region (46), and a second voltage measuring connection (58) on the measuring resistor is formed in the region of the second connection region.

3. The exhaust gas heater according to claim 1 or 2, characterized in that: The voltage measuring section (42) has a resistance characteristic that is different from the resistance characteristic of the heating region (38).

4. The exhaust gas heater according to claim 3, characterized in that: In an operating temperature range, the voltage measuring section (42) has a resistance that changes more strongly as a function of temperature than the heating region (38), or / and in the operating temperature range, the voltage measuring section (42) has a lower resistance than the heating region (38).

5. The exhaust gas heater according to claim 3, characterized in that: The voltage measurement section (42) has a PTC resistance characteristic or an NTC resistance characteristic.

6. An exhaust gas heating system for an exhaust gas system of an internal combustion engine, the exhaust gas heating system comprising at least one exhaust gas heater (10) according to one of claims 1 to 5, through which exhaust gas (A) can flow, and an actuation arrangement (66), the actuation arrangement being used to detect a measurement voltage between a first voltage measuring terminal (54) and a second voltage measuring terminal (58) and to apply a supply voltage between a first supply voltage terminal (28) and a second supply voltage terminal (32) as a function of the detected measurement voltage.

7. The exhaust gas heating system according to claim 6, characterized in that: The control arrangement (66) is designed to apply a supply voltage to be applied between the first supply voltage terminal (28) and the second supply voltage terminal (32) as a function of the detected measurement voltage and a target measurement voltage or a target temperature in the region of the measurement path (42).

8. An exhaust system for an internal combustion engine, comprising an exhaust gas heating system according to claim 6 or 7.

9. A method for operating an exhaust gas heater according to claim 1 , comprising the steps of: a) applying a supply voltage between a first supply voltage connection (28) and a second supply voltage connection (32), b) detecting a measurement voltage between a first voltage measuring connection (54) of the measuring section (42) and a second voltage measuring connection (58) of the measuring section (42), c1) comparing the measured voltage detected in measure b) with a nominal measured voltage in order to determine a voltage deviation between the detected measured voltage and the nominal measured voltage and regulating the supply voltage as a function of the voltage deviation such that the detected measured voltage lies in the range of the nominal measured voltage, or c2) Comparing the temperature determined based on the measured voltage detected in measure b) with a desired temperature to determine a temperature deviation between the determined temperature and the desired temperature and regulating the supply voltage as a function of the temperature deviation so that the determined temperature is within the range of the desired temperature.

10. The method according to claim 9, characterized in that In measure c2), the temperature in the region of the measuring section ( 42 ) is determined using a measured voltage-temperature relationship.

11. The method according to claim 9 or 10, characterized in that The setpoint measurement voltage or the setpoint temperature is predetermined as a function of at least one environmental parameter.

12. The method according to claim 11, characterized in that The exhaust gas temperature of the exhaust gas (A) flowing through the exhaust gas heater (10) is an ambient parameter.

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