Electrical flow heater for a vehicle, in particular an electric vehicle, operating method for a flow heater, and vehicle

Abstract

The invention relates to a method for operating an electric flow heater (14) in a vehicle (10), in particular an electric vehicle (10), the flow heater (14) having a plurality of electric heating circuits (31) for electrically generating a corresponding heating power in a heating section through which a medium (16) to be heated flows, the power control of the respective heating power of the respective heating circuit (31) is carried out by the control circuit (20) by actuating the respective controllable electrical switching element (33) of the respective heating circuit (31), the sum of the respective heating power being set as the total heating power (32). According to the invention, the total heating power (32) is distributed by the control circuit (20) into the heating power of the heating circuits (31) on the basis of configuration data (40), the configuration data (40) being independent of the actual temperature of the medium (16) to be heated.

Description

Technical Field

[0001] The invention relates to a method for operating an electric flow heater in a vehicle, in particular in an electric vehicle. The method proceeds from the fact that the flow heater comprises a plurality of electric heating circuits. The heating circuits can be provided by circuits comprising at least one heating wire and / or at least one heating coil. When the heating circuits are operated, temperature gradients and / or temperature changes occur on the respective heating wires or the respective heating coils, which lead to material stresses which can lead to undesirably early material fatigue, which should be prevented. The invention also comprises a flow heater which can be operated according to the method, and a vehicle having such a flow heater. The vehicle is in particular configured as an electric vehicle. Background Art

[0002] In electric vehicles, such as battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV), the heating / warming of the interior is not effected by the loss heat of the internal combustion engine as in the case of an internal combustion engine, but also or only by an electrically operated flow heater. Alternatively or additionally, the required temperature can be heated by a heat pump, which extracts heat from the high-voltage battery or electric motor. If this is not enough (for example on cold days or at the beginning of driving), the coolant is additionally heated via an electric heating device (ie, an electric flow heater (elektrische Durchlauferhitzer, eDH)). In addition, the eDH is also used to adjust the high-voltage system HVS of the electric vehicle in such a way that the charging time is shortened in many operating situations.

[0003] The electric heating device in an electric flow heater (eDH) has a very high power (e.g. up to 9 kW). In the model of the flow heater used here, the operating principle is as follows: the coolant (medium to be heated) flows through the electric heating device or the heating section and is heated here on one or more heating plates via a plurality of electric heating circuits. In this case, each heating circuit is connected to a high voltage supply (Hochvolt-Spannungsversorgung, HVS) via at least one separate power driver (e.g. a dedicated transistor). The power driver is controlled, for example, via pulse width modulation (PWM) by control electronics (control circuit), whereby the heating power of the heating circuits can be controlled individually or separately. Generally, all heating circuits are supplied with power uniformly.

[0004] DE 42 11 590 C1 discloses an electric flow heater with a cold water inlet, a control device, a heating section and a hot water outlet, wherein the heating section has at least two individually controllable and / or switchable heating elements, at least one of which can be controlled according to the heat demand. Summary of the invention

[0005] The invention is based on operating an electric flow heater for vehicles in a manner that is gentle on the material.

[0006] According to the invention, this object is achieved by the subject matter of the independent patent claims. Advantageous embodiments of the invention are the subject matter of the dependent claims, the description and the drawings.

[0007] As a solution, the present invention includes a method for operating an electric flow heater in a vehicle. The method starts from the fact that the flow heater has a plurality of electric heating circuits, which are used to electrically generate the corresponding heating power in a heating section through which the medium to be heated flows. The heating section can be formed, for example, by a pipe or a channel, which can be flowed through or through by the medium. In a known manner, a fluid, in particular a liquid such as water or oil, can be provided as the medium. The heating circuits can heat the same heating section together or heat different branches or sections of the heating section. In order to heat them, it is necessary to supply them with electric power.

[0008] For this purpose, the control circuit drives the corresponding controllable electrical switching elements (one or more semiconductor switches, MOSFETs, power drivers) of the corresponding heating circuits in order to implement power control of the corresponding heating powers of the corresponding heating circuits, wherein the sum of the heating powers of the individual heating circuits is set as the total heating power, as can be predefined for flow heaters. For example, the total heating power can be predefined by the temperature control circuit, and the distribution to the heating circuits can be controlled by the configuration data.

[0009] The power control in each heating circuit can be performed, for example, based on the mentioned pulse width modulation PWM, by which the corresponding switching element can be switched between different electrical switching states (for example, electrical conduction and resistance disconnection). One or more semiconductor switches, for example, at least one transistor, for example, MOSFET (MOS-Metal Oxide Semiconductor Field Effect Transistor) and / or corresponding bipolar transistors can be respectively arranged in the corresponding switching element. Generally speaking, such an electrical switching element is called a power driver. Since each heating circuit is provided with a switching element of its own, each heating circuit can be controlled or set individually with respect to the heating power converted therein or provided therein by the control circuit. In general, a total heating power is generated, for example, in the case of an air conditioning device, the total heating power can be predetermined by the user, and the user can have predetermined or set the heating level for heating the interior space. In a manner known per se, it can be arranged at least partially on a heating plate or multiple heating plates in the heating circuit, and the heating plates can be made of ceramics, for example, respectively. The conductive lines of the corresponding heating circuit can be connected to the corresponding heating plate or embedded in the corresponding heating plate, for example.

[0010] In order to reduce material fatigue that occurs during operation of the heating circuit due to temperature fluctuations and / or temperature concentrations (hot spots) in the heating plates and / or in the heating sections, the invention provides that a division or distribution of the total heating power to the heating powers of the heating circuits is carried out by the control circuit according to configuration data (stored in a data memory of the control circuit), wherein the configuration data or the distribution predefined by the configuration data is independent of the actual temperature of the medium to be heated. Thus, the power curve or the power distribution is still applied to the actual temperature control by the configuration data.

[0011] The term "configuration data" should be understood broadly here, because it involves data-based control of the control circuit, which can be implemented in many different ways. The following is a feasible example: the configuration data can be implemented as a program-based control of the control circuit. The configuration data can additionally or alternatively specify at least one characteristic field, which can specify the additional distribution of the total heating power to each heating circuit for different operating values ​​and / or operating conditions. In addition or alternatively to this, the configuration data can be pre-set in the control software parameter values, such as at least one threshold value and / or limit value and / or upper limit. In addition or alternatively to this, the configuration data can be implemented, for example, by a function of a parameter, which pre-sets the functional relationship between at least one operating parameter and the heating power to be set for at least one heating circuit. The total heating power can be, for example, in the range of 1kW to 15kW. For flow heaters of this order of magnitude, material fatigue proves to be a special technical problem. Therefore, the total heating power to be provided or generated can now be distributed or divided to different heating circuits by pre-setting the configuration data, so that each heating circuit can be operated with different heating powers. It can be taken into account that one or some of the heating circuits must be operated more gently than at least one of the other heating circuits, because they are arranged, for example, in hot spots, where a disproportionately large local heating can occur (relative to the remaining heating circuits) due to heat accumulation or heat accumulation. By configuring the control circuit in such a way that the control circuit distributes the total heating power to the individual heating circuits according to configuration data, which does not depend on the actual temperature control, but rather determines the distribution ratio universally (i.e. for different presettings of the total heating power), an operating strategy for gentle operation of the flow heater can be superimposed or supplemented for the actual temperature open-loop control or temperature closed-loop control by characteristic data. The power control performed by driving the switching element can be realized by methods in the prior art, for example, by adjusting the current intensity and / or the switch-on time.

[0012] From the simulation data of the numerical simulation, it is possible to determine the expected limits on the feasible operating time / operating cycle in the given electric flow heater eDH. That is, it is possible to determine whether and / or what position of the flow heater is likely to be damaged before the expected or predetermined operating time of the flow heater in the user's operation. Replacement will be expensive. In addition to the pure price of the parts, the vehicle must be stopped / protected from the high voltage point of view, other obstructing parts must be disassembled, the medium line must be emptied and disassembled, and it is also important that this also means great dissatisfaction on the part of the user. By reducing the temperature and / or temperature gradient in the hot spot (hot spot) above the maximum value, failure or malfunction of the heating circuit located there can be avoided.

[0013] The present invention also includes further developments that can achieve additional advantages.

[0014] A further development consists in that the configuration data are permanently predefined or stored in the control circuit. For example, the configuration data can be stored or memorized in the control device when the vehicle is manufactured. If it is known for which vehicle the flow heater is to be used, the configuration file is configured for the vehicle by memorizing or storing the configuration data in the control circuit, so that, for example, it is taken into account which of the heating circuits of the flow heater must be operated with reduced or minimum electrical power relative to the remaining heating circuits, because, for example, the simulation data described by the simulation have already been identified for this heating circuit, if the heating circuit is located in the installation position in the vehicle. Thus, gentle operation can be implemented for different vehicle models with one and the same model of flow heater, without the need to structurally match the flow heater to the corresponding vehicle model.

[0015] Alternatively, the configuration data can be changed (updated) during operation of the control circuit. By means of such a subsequent change of the configuration, for example by means of an update of the configuration data in the control circuit, it is possible to respond to new findings and / or to long-term testing of prototypes, since the operating mode (i.e. the distribution of the heating power to the heating circuits) can also be adjusted in the vehicle (which is already in use by the user).

[0016] The control circuit can switch or select between different configuration data during operation, i.e., the heating circuit can be controlled according to the selected configuration data, depending on the detected current operating situation. With this variant, a plurality of different operating situations can already be taken into account in the configuration data. For example, a plurality of different vehicle models can be taken into account in the configuration data, and the flow heater can be enhanced for the corresponding vehicle model by selecting or switching in the respective configuration data, because the control circuit can then adapt its operation to the vehicle model of the vehicle by selecting the part of the configuration data that is suitable for the vehicle or its vehicle model. For example, the control circuit can be informed by a signal from a communication vehicle network, such as a communication bus, to which vehicle model the vehicle in which the flow heater is installed belongs. The control circuit can then automatically adapt the operating mode of the heating circuit and, in particular, the distribution of the heating power to the vehicle model.

[0017] In the following, it is described by means of exemplary possible embodiments of the control circuit what can be controlled or specified in the control circuit by means of configuration data in order to achieve gentle operation of the flow heater.

[0018] Therefore, a further improvement includes: the conditions for driving the switching element are predefined by configuration data, which predefined the corresponding upper limit of the heating power for one heating circuit or some heating circuits or each heating circuit. In other words, it is avoided that more heating power is set or input in the corresponding heating circuit than allowed by the upper limit. In this way, hot spots or overheating can be avoided for the corresponding heating circuit. By the distribution based on the predefined upper limit, uneven losses of the heating circuit can be avoided. By changing the upper limit over time, it is also possible to achieve or coordinate the losses of the individual heating circuits with the corresponding loss state of another heating circuit.

[0019] A further improvement includes that the configuration data predetermines the following conditions, which stipulate the coordinated switching of the switching elements of at least two heating circuits in the heating circuit (according to the power), and the heating circuits of the at least two heating circuits are arranged directly adjacent to each other in the flow heater, wherein the coordinated switching stipulates the heating power and / or switching state of one heating circuit in the coordinated switched heating circuit and the heating power and / or switching state of another heating circuit in the coordinated switched heating circuit. The mentioned heating circuit can be the described heating wire and / or heating coil, and each heating circuit can have one or more of them respectively. By taking into account the adjacently arranged heating circuits (i.e., the following heating circuits, between which other heating circuits of another heating circuit are not laid or arranged), thermal hot spots can be avoided. For example, the coordinated switching of such heating circuits can stipulate that as a condition, the sum of the heating powers provided by these heating circuits at the same time should be less than a predetermined maximum value. For example, such a maximum value can be determined by simulation. The maximum value can also be set according to the flow rate or flow rate (liters per minute) of the medium. Thus, for example, in areas where the heating lines are at the shortest distance from one another, possible hot spots can be avoided there or their temperature can be kept below a maximum value if the medium otherwise transfers thermal energy too slowly.

[0020] A further improvement includes that the configuration data predetermines the following conditions, which predetermine the synchronous switching of at least two of the switching elements, in particular the switching with a time offset and / or a phase offset. Synchronous switching means that the switching is carried out in a time-coordinated manner, for example in a time-offset manner. This can avoid, for example, in the case of inductively acting electrical structural elements, the possible accumulation or superposition of switching peaks caused simultaneously (such as those caused by induction when the current is interrupted) in the heating circuit. Instead, the switching peaks are caused in a time-offset manner. For periodic or cyclic switching, for example in the case of PWM, the time offset of the switching process of multiple heating circuits can, for example, achieve destructive inertia or elimination of the emitted electromagnetic radiation and / or the ripple voltage in the power supply network, so that, for example, other vehicle components (such as electronic control devices) remain undisturbed.

[0021] A further improvement includes presetting the switching of phase offsets for the following heating circuits in the heating circuit, the electrical heating circuits of the heating circuits and / or the electrical supply circuits of the heating circuits are arranged directly adjacent to each other (without other circuits in between). This adjacent arrangement of the heating circuits and / or the supply circuits is produced, for example, under the twisted pair arrangement structure of the supply circuits and / or under the electrical shielding or electromagnetic shielding of the supply circuits. In order to promote the cancellation effect, the heating circuits can even be laid in parallel to each other in a targeted manner, for example, during the production process of the heating plate, in particular in the form of heating coils n, so that the heating circuits can then be operated in an improved or advantageous manner with respect to electromagnetic compatibility EMC by switching the phase offset (in particular with a phase offset of 180 degrees). The antenna effect of the heating circuit can then be compensated by the antenna effect of another heating coil by means of the phase offset by means of destructive inertia. Therefore, at least two heating circuits in the heating circuit can be provided with phase-shifted pulse operation, for example with a pulse rate in the range of 5 Hz to 50 kHz, which pulse rate can be present or used in particular in pulse width modulation, which is then carried out in a phase-shifted manner, in particular with a phase offset of 180 degrees.

[0022] Another advantageous embodiment is provided with respect to pulse width modulation, in which the synchronous switching is predefined by configuration data for all switching frequencies or only for some of the switching frequencies that are predefined or possible by PWM. Since pulse width modulation changes the pulse frequency or predefined pulse-changing switching frequencies within a predefined frequency range during operation, it can happen that only occasionally certain interfering switching frequencies can generate electromagnetic interference caused by the heating circuit in the vehicle, which can interfere with radio transmitters, for example. If such switching frequencies are known, the elimination or attenuation of electromagnetic interference radiation achieved by the described synchronous switching can be predefined by predefining corresponding configuration data.

[0023] A further improvement includes that the configuration data specifies different distributions of the total heating power for different installation positions and / or spatial installation postures of the flow heater in the vehicle and / or for different vehicle models, and the control circuit selects the following configuration data in the configuration data, which is specified for the actual installation position and / or installation posture of the flow heater. The installation position and / or installation posture can be represented by a signal through the predetermined position data. The control of the switch element and the setting of the heating power are performed in the switch element according to the selected configuration data.

[0024] An important realization is that the installation position, i.e. the spatial proximity to other vehicle components of the vehicle and / or the installation posture, such as inverted or horizontal installation, may have an influence on the temperature distribution and / or heat dissipation in the flow heater. In addition, due to the proximity to other vehicle components, overheating or material fatigue may also occur there due to heat radiation. By pre-specifying the corresponding configuration data, the installation position and / or installation posture can be taken into account when distributing the total heating power to the heating circuit. If it is then known in what installation position and / or installation posture the flow heater is installed in the vehicle (this can be achieved, for example, by signaling the vehicle model via the described communication vehicle network), the operation of the flow heater can be adjusted or configured accordingly. For example, the vehicle's control device can use a signal to indicate which vehicle model is present. Where signs of fatigue may occur due to the installation position and / or spatial installation posture can be achieved or achieved in the described manner by simulation and / or by statistics of damage reports.

[0025] During operation of the flow heater, differently advantageous or differently detrimental operating states may occur, which can then be responded to by correspondingly predefining state-specific configuration data in such a way that the distribution of the heating power to the heating circuit is adapted to the operating state.

[0026] A further improvement includes, by means of a control circuit, according to the configuration data, adjusting the distribution and / or the control of the switch element differently for different operating states of the flow heater and / or for different operating modes, the different operating states are different with respect to the flow conditions (flow velocity, flow rate) of the medium, and the different operating modes are different with respect to the fluid coupling of the heating section with different vehicle components of the vehicle. Thus, for example, it can be taken into account that the cooling effect of the medium convection heater decreases with the decrease of the flow velocity and / or flow rate. In addition and alternatively to this, hydraulic conditions can also be regarded as different operating modes and corresponding configuration data can be provided, the hydraulic conditions can be generated by the coupling of different vehicle components (for example, an air conditioning compressor on the one hand and an air conditioning device of the traction battery of the vehicle on the other hand). Then, by this, the control of the switch element (for example, the coordinated operation of the switch element) or the distribution of the heating power (for example, the distribution is performed by presetting an upper limit according to the operating mode) can be changed or matched to the operating mode. The operating state or operating mode can be measured by means of a sensor circuit of the flow heater itself (e.g. flow rate and / or pressure in the medium) and / or it can be signaled from another control device of the vehicle which controls, for example, a valve for the hydraulic coupling.

[0027] A further improvement includes that the total heating power is distributed and / or the switching elements are controlled by the control circuit according to the configuration data according to the corresponding operation history. The operation history particularly gives the age and / or operating hours and / or the total energy converted of the corresponding heating circuit. If, for example, it is known from the operation history that the flow heater has performed more cold starts than a predetermined threshold, the following heating circuit can be reduced or adjusted in terms of the heating power converted by the heating circuit with the help of the configuration data, and the heating circuit is particularly damaged or fatigued due to such cold starts. In addition or alternatively to this, the absolute age of the heating circuit and / or the number of operating hours and / or the total converted energy can also be determined or recorded for the heating circuit. Here, if the operation history indicates with a signal that the loss limit has been reached for at least one of the heating circuits or the loss state has reached a predetermined limit value, redistribution or power transfer can be triggered. Therefore, uniform material fatigue and / or uniform loss of the heating circuit can be achieved.

[0028] The control principle for a flow heater is described again in general terms below.

[0029] The configuration data can be used to predetermine different (e.g., proportional) shares of the corresponding heating power with respect to the total heating power and / or the power upper limits for two or more or all heating circuits in the heating circuit for different possible operating conditions, and the flow heater in the vehicle can be operated continuously and / or temporarily in the different possible operating conditions. The control circuit can determine the situation data by means of its own sensor circuit and / or by receiving from another control device, and the situation data represents the actual operating condition with a signal. The control of the switching element of the heating circuit can be carried out according to the following configuration data in the configuration data, and the configuration data is predetermined for the operating condition represented by the situation data with a signal. The operating data has been given, for example, in the following way: the flow heater is continuously installed and / or retained in a vehicle of a certain vehicle model. The matching of the vehicle model and / or the installation position and / or the installation posture described can be performed here. The control of the switching elements and / or the distribution of the heating power can be changed by determining a change in the current operating situation, which can change during the operation of the vehicle, because, for example, different vehicle components can be coupled to the flow heater at different times and / or the flow of the medium changes. By signaling the current operating situation to the control circuit and / or the control circuit itself determining the current operating situation, situation data are generated, with the help of which configuration data can then be selected and / or with the help of which the distribution of the heating power and / or the control of the switching elements can be carried out differently for different operating situations.

[0030] A further development for this purpose consists in that the configuration data contain a coding flag, the state of which controls whether the assignment is always activated or only activated according to a logic consisting of vehicle parameters, in particular the country version, the target market, the material variant of the heating plate and / or whether it is a special cold country vehicle. This means that in addition to the permanent activation of the method in the vehicle, the method can now also be coded according to a logic consisting of vehicle parameters, such as the country version, the target market, the material variant of the heating plate (for example, if it comes from multiple suppliers or it is (necessarily) purchased locally in a specific market), or whether it is a special cold country vehicle. This is information that can be present in the vehicle order and can be taken into account for coding.

[0031] A further improvement to this end includes that the situation data is determined from an onboard network and / or by means of a sensor circuit of the flow heater, to which the flow heater is coupled. By means of a communication onboard network, such as a CAN bus (CAN-Controller Area Network), the control circuit can be informed by a signal via at least one other vehicle component: which operating situation currently exists and / or which operating mode is to be set in the flow heater and / or which configuration data in the configuration data are valid. By means of the sensor circuit, the control circuit can autonomously determine in the vehicle which configuration data are to be used. For example, the transmitter circuit can include a gyroscope sensor, by means of which the installation posture of the flow heater can be autonomously determined by the flow heater and its control circuit.

[0032] A further development consists in that after the configuration data have been used and in the maintenance mode, new configuration data are received by the control circuit and the configuration data are completely or partially replaced and / or supplemented by the received new configuration data. In the maintenance mode (as the maintenance mode can be set in the flow heater, for example, during an over-the-air update and / or in the factory), the configuration data can be updated or supplemented. Thus, the flow heater can also provide further information about the wear sensitivity of the heating circuit during operation or during the life of the flow heater in the vehicle and corresponding countermeasures can be implemented.

[0033] As a further solution to the task, the present invention comprises an electric flow heater having a plurality of electric heating circuits, each of which is connected to a connection device for supplying electrical energy to the corresponding heating circuit via a corresponding controllable electric switching element. The control circuit of the flow heater can, for example, be based on at least one microcontroller and / or at least one microprocessor and / or an ASIC (application-specific integrated circuit). The method steps described here can also be implemented as software or program code in the control circuit and stored in a data memory of the control circuit. The connection device can, for example, include a plug or a socket with an electrical contact element, so that the flow heater is electrically connected to the vehicle's onboard power supply, for example a high-voltage vehicle network (high voltage - voltage greater than 60V, in particular greater than 100V) via the connection device.

[0034] The flow heater comprises a control circuit for power control of the electrical power (heating power) switched by the switching element in the respective heating circuit and is provided for carrying out an embodiment of the method described here.

[0035] As a further solution to the object, the invention comprises a vehicle having an embodiment of an electric flow heater described here. As already described, the vehicle is in particular an electric vehicle, i.e., for example, a BEV or PHEV as described at the beginning. In the vehicle, the operating state and / or operating history can then be taken into account and controlled by configuration data: to what extent or how the distribution of the heating power should be carried out in order to achieve the total heating power in the heating circuit. Thus, a local or internal temperature distribution in the flow heater can be carried out by configuration data according to regulations concerning material fatigue or loss or electromagnetic compatibility.

[0036] Further features of the invention are derived from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned above in the description and the features and feature combinations mentioned below in the description of the drawings and / or shown alone in the drawings can be used not only in the respectively indicated combination but also in other combinations or alone. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will now be explained in more detail with the aid of preferred embodiments and with reference to the accompanying drawings.

[0038] Figure 1 A schematic diagram showing an embodiment of a motor vehicle with an electric flow heater according to the invention; and

[0039] Figure 2 Schematic diagrams showing flow heaters with different embodiments of the heating circuit. DETAILED DESCRIPTION

[0040] Figure 1 A vehicle 10 is shown, which can be a motor vehicle, in particular a passenger car. The vehicle 10 can be designed as an electric vehicle. An electrical energy source 11 can be provided in the vehicle 10, which can be, for example, a vehicle battery (traction battery or high-voltage battery). In order to warm or heat at least one vehicle component 12, 13, a flow heater 14 can be provided in the vehicle 10, which can be fluidically coupled to the vehicle components 12, 13 via a heating circuit 15 in order to heat a medium 16, for example a water-based or oil-based liquid. For example, the state of the fluid coupling can be changed via a valve 17. For example, an air conditioning device for the passenger compartment of the vehicle 10 and / or an air conditioning device for the vehicle battery can be provided as vehicle components 12, 13.

[0041] For the energy supply or electrical power supply of the flow heater 14 , the flow heater can be connected via a connection device 18 , for example an electrical socket or an electrical plug, to an onboard electrical system 19 which can be supplied with electrical power via the energy source 11 .

[0042] The flow heater 14 may have a control circuit 20, which may be coupled to at least one further electronic component 22, such as a corresponding electronic control unit (ECU) via a communication onboard network 21 for exchanging situation data 23. The communication onboard network 21 may be based, for example, on the already mentioned CAN bus and / or Ethernet and / or Lin bus. The situation data 23 may, for example, represent the switching state of the valve 17 in the form of a signal. In addition and as an alternative to this, a sensor circuit 24 may be provided in the flow heater 14 itself, with the aid of which the control circuit 20 may detect sensor data 25 as situation data, such as a spatial installation posture 26, which is detected in the Figure 1 It is symbolically represented by a coordinate system.

[0043] In the vehicle 10 , the flow heater 14 may operate gently with respect to material loss and / or material fatigue.

[0044] to this end, Figure 2 A heating plate 30 is shown, which can be made of, for example, ceramic, and a medium 16 can be guided or flowed past the heating plate 30, thereby generating a heating section for the medium. In order to heat the heating plate 30, an electric heating circuit 31, i.e., a circuit that can be supplied with electric power from the vehicle power supply 19, can be provided. The required or requested total heating power 32 can be received, for example, from one of the electronic components 22 (for example, an air conditioning control device or generally speaking, an onboard electronic device) via the communication vehicle network 21. The corresponding heating power of the heating circuit 31 can be individually adjusted by the control circuit 20 with respect to the current or electric power in the heating circuit via the corresponding switching element 33, and the switching element can be, for example, based on at least one semiconductor power switch, for example, at least one transistor and / or thyristor. This individual control of the switching element by the control circuit 20 for adjusting the heating power can be implemented, for example, on the basis of pulse width modulation. In the corresponding heating circuit, the electric power can be converted into heat, for example, by a heating wire 34 and / or a heating coil n (heating spiral), and discharged in or on the heating plate 30.

[0045] This may result in different temperature distributions on the heating plate 30 and / or in the heating circuit 31 and / or temperature gradients in the heating plate 30 and in the heating circuit 31. This may lead to the formation of hot spots (hot spots) or heat concentrations, at which material fatigue may be greater than in other areas of the flow heater 14. In addition or as an alternative thereto, the heating coil n may in particular generate electromagnetic radiation 36.

[0046] This can be addressed structurally, for example, by shielding structures 37 of the input lines or supply lines of the heating circuit and / or by the geometrical arrangement structure 38 of the heating circuit, or the influence of the electromagnetic radiation 36 or its intensity can be reduced. In addition, the reduction of the electromagnetic radiation 36 can be achieved by correspondingly actuating the switching elements 33. The switching behavior or actuation of the switching elements 33 or the division of the requested total heating power 32 into the respective heating powers of the corresponding heating circuits 31 can be carried out according to configuration data 40, which can be stored or implemented in the control circuit 20 and are based on knowledge or information about the formation of hot spots for different operating modes and / or different installation postures of the flow heater 14. Such information can be based on, for example, by means of simulations and / or error reports from vehicles that are already in operation.

[0047] In different vehicle models, the same heating device is installed in different positions and orientations. As a result, the temperature distribution on the heating plate and in the entire component and the flow behavior of the coolant change mainly in the eDH. This may even lead to functional differences. However, the heating device is not adapted for this, so the heating device cannot work optimally and the effective efficiency (how much energy is released to the coolant in the form of heat) is reduced. Since the heating device requires high power, a large amount of installation space is required, and in order to meet the requirements, the materials used for the heating plate must be of very high quality. This results in high proportional costs. In addition, as a result of the high power, there is an increased risk of heating power breakdown or other failures. Therefore, the service life of the eDH is short, and there is even a risk that the vehicle remains immobile, which leads to user dissatisfaction and high warranty costs. Depending on the operating mode, the charging time of the vehicle may also be significantly extended.

[0048] This concept provides that the individual heating plates or heating circuits can be controlled individually and no longer all be operated with the same power, but rather the power varies depending on the situation.

[0049] There are several possibilities to communicate to the heating plate: in which operating state, operating history, installation posture and orientation the heating plate is in. The first possibility is, for example, to transmit a signal with information via the vehicle network. This must be determined in advance for each vehicle model and then the required software is adjusted for it. The second possibility is to automate this process by attaching additional sensors (such as simple gyroscopes) to the plate, so that it can independently identify how it is positioned. If this is now determined, the same amount of power is no longer allocated to all plates, but the power control is optimized according to the situation. An example of this is that the heating plate installed further down is turned on more strongly because the heat rises upward (efficiency), and vice versa accordingly. Or the heating plate installed further down is turned on more weakly compared to the heating plate located above, so that the temperature load in the component, other heating plates and / or electronic components can be better derived. Another option is to operate the following heating plate or part of the heating plate with a smaller power according to the situation, which has a higher risk of damage due to temperature from a flow perspective. In the case of corresponding synchronization and design, this solution also leads to improved results in terms of electromagnetic interference radiation to the components. In particular, when using very fast and therefore energy-efficient power drivers, the radiated electromagnetic power is an obstacle, and improving it is beneficial to the energy efficiency of the eDH. Another variant is to control the drive synchronously in pairs with a phase shift of 180°. In this case, the EMC interference that inevitably occurs can be further suppressed in the case of a close geometric arrangement of the power supply lines to the heating plate (for example, by coaxial wiring and / or shielded lines) and a close geometric arrangement of the heating wires on the heating plate. This will become even more important in the future with the continuous and expected development of faster power drivers.

[0050] A possible implementation of the concept provides that additional vehicle network signals are required in order to control the power switches in terms of the operating mode and possibly transmit information via the communication vehicle network (e.g. CAN bus). However, this one-time cost is insignificant and, above all, it is not reflected in the proportional component costs per vehicle. In addition, one power output is now not sufficient to control all switches, but each switch requires its own connection. However, this is already common in technology, because small or low-power power driver functional components for switch elements are disproportionately more cost-effective.

[0051] Power control can avoid early failure of the eDH due to, for example, cable burn-through or component damage. Alternatively, under the same long-term reliability, the system can still operate with a more cost-effective and smaller heating plate of the same power. The eDH can be used in various vehicle models and can still be purchased as a standard device / universal component across multiple vehicle derivatives (i.e., installation posture, installation environment, and flow conditions of the medium), so that economies of scale can be better utilized in terms of cost. Optimized power control seeks to require optimized and therefore potentially lower power overall for the same heating effect. Through the energy saved, BEVs and PHEVs benefit from a higher maximum range and lower energy costs for the same distance. The operating state / operating history can also be taken into account to ensure the optimized heating power for the user permanently. Another advantage is that by pre-implementing in the device SW (SW-Software, software), the mode can also be technically changed at a subsequent time point, if, for example, new knowledge of failure statistics and warranty situations only appears after the production of the vehicle is started. Then only the revised and improved mode needs to be set by software updates, which generally occur during the life cycle of the vehicle. As a result, no mechanical repair costs are incurred and the measures can be effective even before damage occurs in the vehicle and increase robustness.

[0052] This shows how the concept described can be used to avoid hot spots in an electric flow heater.

[0053] Reference numerals list

[0054] 10 Vehicles

[0055] 11Energy

[0056] 12 Vehicle Components

[0057] 14 Flow Heater

[0058] 15 Heating circuit

[0059] 16 Medium

[0060] 17 valves

[0061] 18 Connecting device

[0062] 19 On-board power grid

[0063] 20 Control circuit

[0064] 21 Communication Vehicle Network

[0065] 22 Components

[0066] 23 Situation data

[0067] 24 sensor circuit

[0068] 25 Sensor data

[0069] 26 Installation posture

[0070] 30 Heating Plate

[0071] 31 Heating circuit

[0072] 32 Total heating power

[0073] 33 Switching elements

[0074] 34 Heating wire

[0075] 36 Radiation

[0076] 37 Shielding structure

[0077] 38 Arrangement structure

[0078] 40 Configuration data

Claims

1. A method for operating an electric flow heater (14) in a vehicle (10), in particular an electric vehicle (10), wherein: The flow heater (14) has a plurality of electric heating circuits (31) for electrically generating corresponding heating powers in a heating section through which a medium (16) to be heated flows, and a control circuit (20) controls the power of the corresponding heating powers of the corresponding heating circuits (31) by driving corresponding controllable electric switching elements (33) of the corresponding heating circuits (31), wherein the sum of the individual heating powers is set as a total heating power (32). It is characterized in that The control circuit (20) distributes the total heating power (32) to the heating powers of the individual heating circuits (31) according to configuration data (40), wherein the distribution specified by the configuration data (40) is independent of the actual temperature of the medium (16) to be heated.

2. The method according to claim 1, wherein: The configuration data (40) of the control circuit (20) are permanently predetermined or are changed during operation of the control circuit (20), or the control circuit (20) selects between different configuration data of the configuration data (40) during operation according to a detected current operating situation, and the control is performed according to the respectively currently selected configuration data (40).

3. A method according to any one of the preceding claims, wherein: Configuration data (40) for actuating the switching element (33) predetermine conditions to be observed by the control circuit (20), which conditions include a respective upper limit of the heating power of at least one heating circuit or some heating circuits or each heating circuit of the heating circuits (31).

4. A method according to any one of the preceding claims, wherein: The configuration data (40) predetermines conditions to be complied with by the control circuit (20), the conditions specifying coordinated switching of switching elements (33) of at least two of the heating circuits (31), the electrical heating circuits of the at least two heating circuits being arranged directly adjacent to each other in the flow heater (14), wherein the coordinated switching specifies a correlation between the heating power and / or switching state of one of the coordinatedly switched heating circuits (31) and the heating power and / or switching state of another of the coordinatedly switched heating circuits (31).

5. A method according to any one of the preceding claims, wherein: The configuration data (40) prescribe conditions to be observed by the control circuit (20), which prescribe synchronous switching, in particular time-shifted and / or phase-shifted switching, of at least two of the switching elements (33).

6. The method according to claim 5, wherein: The switching of the phase offset is predefined for those of the heating circuits (31) whose electrical heating lines and / or whose electrical supply lines are arranged directly adjacent to each other.

7. The method according to claim 5 or 6, wherein: The switching element (33) is controlled by the control circuit (20) as pulse width modulation (PWM), and the synchronous switching is predefined by configuration data (40) for all switching frequencies or only for some of the switching frequencies specified by PWM.

8. A method according to any one of the preceding claims, wherein: The configuration data (40) specifies different distributions of the total heating power (32) for different installation positions and / or spatial installation postures (26) of the flow heater (14) in the vehicle (10) and / or for different vehicle models, and the control circuit (20) selects the following configuration data in the configuration data (40), which is specified for the actual installation position and / or installation posture (26) of the flow heater (14) based on predetermined position data, and implements the control based on the selected configuration data (40).

9. A method according to any one of the preceding claims, wherein: The control circuit (20) adjusts the distribution of the total heating power and / or the actuation of the switching element (33) differently according to the configuration data (40) for different operating states of the flow heater (14) and / or for different operating modes, wherein the different operating states are different with respect to the flow conditions of the medium (16) and the different operating modes are different with respect to the fluid coupling of the heating section with different vehicle components (12) of the vehicle (10).

10. The method according to any one of the preceding claims, wherein: The control circuit (20) distributes the total heating power (32) and / or controls the switching elements (33) in accordance with configuration data (40) based on a corresponding operating history, which indicates the age and / or operating hours of the corresponding heating circuit (31) and / or the total energy converted.

11. A method according to any one of the preceding claims, wherein: Different portions of the corresponding heating power relative to the total heating power (32) and / or upper power limits are predefined for one heating circuit, some heating circuits or all heating circuits in the heating circuits (31) by means of the configuration data (40) for different possible operating situations, the operating situation being permanently and / or dynamically defined for a flow heater (14) in a vehicle (10), and situation data (23) are determined by means of a control circuit (20), the situation data characterizing the actual operating situation with a signal, and the control is performed according to the associated configuration data (40), and / or The configuration data contain a coding flag by means of which it is controlled that the assignment is activated only as a function of a logic consisting of vehicle parameters, in particular the country version, the target market, the material variant of the heating plate and / or whether it is a special cold country vehicle.

12. The method according to claim 11, wherein: The situation data (23) are determined from a communication onboard network and / or by means of a sensor circuit (24) of the flow heater (14), to which the control circuit (14) is coupled.

13. A method according to any one of the preceding claims, wherein: After the configuration data (40) have been used, new configuration data are subsequently received by the control circuit (20) in a maintenance mode, and the configuration data (40) are completely or partially replaced and / or supplemented by the received new configuration data.

14. An electric flow heater (14) having a plurality of electric heating circuits (15), each of which is connected to a connection device (18) via a corresponding controllable electric switching element (33) for supplying the corresponding heating circuit (15) with electric energy, It is characterized in that A control circuit (20) of the flow heater (14) is provided for power control of the electrical power switched in the respective heating circuit (15) by means of a switching element (33) and is configured to carry out a method according to any of the preceding claims.

15. A vehicle (10), in particular an electric vehicle (10), having an electric flow heater (14) according to claim 14.

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