Method, control unit and vehicle for reducing magnetic interference in the vehicle interior

Abstract

The invention relates to a method for reducing magnetic, electrical, and / or electromagnetic interference emanating from the vehicle electrical system (10) of a vehicle (1) and influencing the vehicle interior (1). For at least one predetermined sub-area (12, 13) of the vehicle electrical system (10), a total current (G1, G2) is determined from the sum of the partial currents (I) flowing through each sub-area (12, 13). From all the electrical devices (20, 30) supplied via the vehicle electrical system (10), the electrical comfort consumers (30) whose power consumption can be modulated are identified. The power consumption of the modulated electrical comfort consumers (30) is controlled such that the total current (G1, G2) of each predetermined sub-area (12, 13) of the vehicle electrical system (10) does not exceed a respective maximum value.The invention further relates to a control unit (40) for carrying out the method and to a vehicle (1) with such a control unit (40).

Description

[0001] The invention relates to a method for reducing magnetic interference emanating from a vehicle's electrical system and spreading into the vehicle's interior. The invention further relates to a control unit for carrying out such a method and to a vehicle comprising such a control unit.

[0002] In modern vehicles, a multitude of electrical consumers are powered via the vehicle's electrical system. Depending on the wiring of this system and the power consumption of the activated electrical consumers, currents flowing along the system's supply lines can radiate magnetic fields of considerable strength into the vehicle interior. Such magnetic fields can potentially impair the medical function of active implanted medical devices (AIMDs) in vehicle occupants or, in extreme cases, destroy them. Examples include cochlear implants, implanted insulin pumps, implanted pacemakers or defibrillators, and similar active medical devices.

[0003] Limit values, particularly for low-frequency magnetic fields, have not been thoroughly investigated for vehicle interiors. Therefore, conservative limits are often recommended, which are, to an unspecified but presumably considerable extent, below the magnetic and / or electric field strength at which safe operation of AIMDs would still be possible.

[0004] Ensuring that such recommended limits for magnetic and / or electromagnetic interference from the vehicle's electrical system are consistently below the limits under all operating conditions and throughout the entire vehicle interior is only possible with considerable technical effort and / or by accepting significant limitations in the supply of electrical consumers in the vehicle.

[0005] In contrast, measures to limit magnetic and / or electromagnetic interference are only relevant under certain, comparatively rare operating and usage conditions, in particular only when there are actually people with an AIMD in the vehicle interior and there is a risk of interference due to an exceptionally high power consumption of electrical consumers.

[0006] Therefore, there is a need for a method that allows such interference limitation to be controlled situationally and as required, in order to reduce negative effects of such measures, particularly on the development and manufacture and on the range of functions of vehicles.

[0007] From DE 10 2021 116 576 A1, a method for reducing electromagnetic influence and a motor vehicle with a plurality of electrical devices are known, wherein the motor vehicle has a control unit which is designed to execute at least one predetermined electromagnetic environmental compatibility setting (EMC setting) during operation of the motor vehicle and, depending on the EMC setting, to control predetermined electrical devices of the plurality of electrical devices to reduce electromagnetic influence in a vehicle interior of the motor vehicle.

[0008] US Patent 2023 0150369 A1 describes a method for reducing magnetic fields in the interior of a vehicle, whereby the total electric current in a predetermined area of ​​a vehicle occupant is determined and, if necessary, the power consumption of electrical consumers is reduced. It is tested whether the strength of the generated magnetic field reaches or exceeds a predetermined reference value.

[0009] The invention is based on the objective of providing an improved method for reducing magnetic and / or electromagnetic interference emanating from a vehicle's electrical system and spreading into the vehicle's interior, which in particular enables a simple design of the electrical system and / or minimal impairment of the function of electrical devices powered by such an electrical system. This objective is achieved according to the invention by a method with the features of claim 1.

[0010] Furthermore, the invention is based on the objective of providing a control unit for carrying out such a method. This objective is achieved according to the invention with a control unit having the features of claim 4.

[0011] Furthermore, the invention is based on the objective of providing a vehicle with such a control unit. This objective is achieved according to the invention with a vehicle having the features of claim 5.

[0012] Advantageous embodiments of the invention are the subject of the dependent claims.

[0013] In a method for reducing magnetic and / or electromagnetic interference (AMI) emanating from a vehicle's electrical system and affecting the vehicle's interior, a total current is determined for at least one predetermined section of the electrical system from the sum of all partial currents flowing through that section. Such sections of the electrical system, also known as hotspots, which, due to their arrangement and geometry and / or the currents flowing through them to supply electrical devices in the vehicle, emit a magnetic and / or electric field strength that is particularly critical for AIMDs in the vehicle interior, can be identified in advance based on the vehicle design, and in particular the electrical system and the electrical devices it powers, for example, using simulation methods.

[0014] From all electrical devices powered by the vehicle's electrical system, the electrical comfort consumers whose power consumption can be modulated are identified. Here and in the following, comfort consumers are defined as electrical devices in the vehicle whose electrical power consumption can be reduced or switched off without impairing the vehicle's functional safety, operational safety, or road safety.

[0015] Such comfort consumers can include, for example, seat heating, seatbelt heating, or an audio system for playing entertainment content in the vehicle. In contrast, electrical devices whose power consumption cannot be reduced without impairing the vehicle's operational or road safety are referred to here and in the following as functional consumers. Comfort consumers can be identified based on their device type or by other means from the vehicle's design.

[0016] According to the invention, the power consumption of the modulatable electrical comfort consumers is controlled in such a way that the total current of each predetermined sub-area (hotspot) of the vehicle electrical system does not exceed a respective assigned maximum value. The total current can be determined as the sum of all partial currents flowing to supply the electrical devices through supply lines installed in the respective sub-area of ​​the vehicle electrical system. Thus, the total current for a hotspot can be determined from the known topology of the vehicle electrical system by determining the supply currents of all electrical devices and, if necessary, averaging them according to the electrical resistances of the individual supply lines, summing them up.

[0017] This method makes it possible to comply with recommended limits for magnetic, electrical, and / or electromagnetic interference while maintaining the greatest possible degree of comfort functions for consumer devices. At the same time, the method enables the design of particularly simple electrical systems that do not require additional protective measures (such as shielding plates, alternative routing of supply lines, and / or switchable partial electrical systems).

[0018] In one embodiment of the method, it is determined in advance whether vehicle occupants with AIMDs require special protection from magnetic and / or electromagnetic interference. The method is then only executed if a special protection requirement is identified. Such situational restriction of comfort functions ensures largely unaffected operation of these functions.

[0019] According to further aspects of the invention, at least one control unit configured to carry out such a method, as well as a vehicle with at least one such control unit, are provided. The advantages according to these aspects of the invention correspond to the advantages of the method according to the invention.

[0020] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0021] This shows: Fig. 1. A purely schematic representation of a vehicle's electrical system and Fig. 2. A purely schematic representation of the power budget of devices supplied via an on-board electrical system.

[0022] Corresponding parts are assigned the same reference symbols in all drawings.

[0023] Fig. Figure 1 shows a purely schematic representation of the electrical system 10 of a vehicle 1. The electrical system 10 comprises a large number of supply lines 11, which are not differentiated in detail here. Electrical devices 20, 30 are supplied with a predetermined electrical system voltage via the electrical system 10.

[0024] Some of these electrical devices 20, 30 are designed as functional consumers 20 whose power consumption cannot be modulated because this could impair the operational safety of the vehicle 1 and / or road safety. Functional consumers 20 can be, for example, a rear window heater, a control unit for an Electronic Stability Program (ESP), or a control unit for an Advanced Driver Assistance System (ADAS).

[0025] Other electrical devices 20, 30 are designed as comfort consumers 30, which improve driving comfort but whose functionality can be reduced or even switched off without impairing operational or traffic safety. Such comfort consumers 30 can be, for example, rear seat heating, rear seat belt heating, rear fan / heater, seat massage units, steering wheel heating, cooling compartments, or audio amplifiers.

[0026] Each electrical device 20, 30 is supplied via the vehicle electrical system 10 with a partial current I, which is determined by a subsequent calculation based on Fig. The operating state Z1, Z2 of the electrical device 20, 30, which is explained in more detail below, may depend on this. For example, the heating power of a rear fan / heater can be varied so that – with an essentially constant vehicle electrical system voltage – the partial current I drawn varies proportionally.

[0027] Typically, a vehicle electrical system 10 has specific sub-areas 12, 13 where, due to limited installation space, a particularly large number of supply lines 11 must be bundled together. Such bundles of supply lines 11 are referred to as wiring harnesses, in which partial currents flow through the individual supply lines 11, resulting in a total current for the wiring harness in one of the sub-areas. Due to this bundling, these sub-areas 12, 13, also referred to as hotspots, exhibit particularly high current densities and dominate the magnetic, electrical, and / or electromagnetic interference radiated into the vehicle interior.

[0028] The first and second hotspots 12 and 13 in the area of ​​the right and left side sills, respectively, are shown here only as examples and schematically. Further hotspots, not shown here, could be located, for example, in the passenger footwell, in the center tunnel, or in a side panel or a body pillar, such as the A- or B-pillar of vehicle 1.

[0029] The design of vehicle 1 reveals the location and extent of hotspots 12, 13. Furthermore, it is known to what extent electrical devices 20, 30 draw partial currents I through these hotspots 12, 13. Therefore, if the power consumption (and thus the drawn partial current I) is known for each of the devices 20, 30, the total current G1, G2 flowing through each hotspot 12, 13 can be determined.

[0030] The invention is based on the idea of ​​monitoring and controlling the power consumption of the comfort consumers 30 via a special control unit 40 designated as AIMD Guard 40. The control is carried out in such a way that a maximum total current, individually defined or definable, is not exceeded at any of the hotspots 12, 13.

[0031] Fig. Figure 2 illustrates the procedure for controlling the comfort consumers 30 by the AIMD Guard 40. Fig. 2 compares the budget of the cumulative power consumption P of all electrical devices 20, 30 in a first operating state Z1 and in a second operating state Z2.

[0032] A certain initial power output P1, the same in both operating states Z1 and Z2, is used as base load, as well as by non-modulating continuous loads and / or for cooling. A certain second power output P2, also the same in both operating states Z1 and Z2, is used by functional loads 20 whose power consumption cannot be limited without jeopardizing the functional, operational, or traffic safety of the vehicle 1.

[0033] However, a third partial power P3 is consumed in the first operating state Z1 by comfort consumers 30, whose power consumption can be limited.

[0034] The AIMD Guard 40 limits the power consumption of these comfort consumers 30 in such a way that the total power consumption P, cumulative across all electrical devices 20, 30, does not exceed a predefined maximum power consumption Pmax. To achieve this, the AIMD Guard 40 controls the comfort consumers 30 in the second operating state Z2 so that they consume only a reduced third partial power P3' compared to the third partial power P3.

[0035] This is based on the finding that with such a limited cumulative power consumption P, the total current G1, G2 at each of the hotspots 12, 13 is limited in such a way that the magnetic fields radiated there into the vehicle interior do not pose a risk of AIMDs to vehicle occupants.

[0036] For example, when driving in winter conditions (outside temperature 4 degrees Celsius or below), the AIMD Guard 40 controls a rear fan / heater at reduced power. Additionally or alternatively, the seatbelt and seat heaters in the rear are switched off. While this reduces the comfort of the rear passengers, it does not affect the vehicle's operational or road safety.

[0037] At the same time, this increases the safety of AIMDs for vehicle occupants because, due to the reduction of the total current G1, G2 in the hotspots 12, 13, they are no longer exposed to potentially dangerous magnetic fields. Comfort functions of comfort consumers 30 are offered to the greatest extent possible, taking into account the safety of the AIMDs.

[0038] The proposed method thus enables the construction of simple on-board networks 10 that do without costly additional measures to reduce the radiated magnetic field strength (for example, by shielding plates, alternative more complex on-board network topologies, switchable on-board networks 10 or similar measures).

[0039] In one embodiment of the method, the AIMD Guard 40 controls comfort consumers 30 to reduce their power consumption (i.e., in this case, to absorb a third reduced partial power P3) only if it has been previously determined that at least one vehicle occupant is wearing an AIMD. Otherwise, the comfort consumers 30 are operated without restrictions.

[0040] The need for protection of vehicle occupants can be detected, for example, at the start of the journey via user interaction, such as through a query in a dialog presented by an infotainment unit of vehicle 1 (not described in detail here). This can be advantageous if vehicle occupants with AIMD only use vehicle 1 occasionally, while regular use can take place without such restrictions.

[0041] Alternatively or additionally, such a need for protection can also be captured via a user profile that is permanently or at least non-volatilely assigned to vehicle 1 via a configuration. This will be particularly advantageous if a user restricted by an AIMD uses vehicle 1 regularly or at least repeatedly.

[0042] By configuring the procedure in this way, which is geared towards the actual need for protection, the least possible restriction of comfort functions for the comfort consumers 30 is achieved.

Claims

[1] Method for reducing magnetic, electrical and / or electromagnetic interference emanating from an on-board electrical system (10) of a vehicle (1) and spreading into the interior of the vehicle (1), characterized by , that - for at least one predetermined sub-area (12, 13) of the vehicle electrical system (10) a total current (G1, G2) is determined from the totality of the partial currents (I) flowing through this sub-area (12, 13) in each case, - from the totality of electrical devices (20, 30) supplied via the vehicle electrical system (10), the electrical comfort consumers (30) whose power consumption can be modulated are determined, - the modulatable electrical comfort consumers (30) are controlled in their power consumption in such a way that the total current (G1, G2) of each predetermined sub-area (12, 13) of the vehicle electrical system (10) does not exceed a respective assigned maximum value. [2] Method according to claim 1, characterized by, that the standard execution of the procedure is activated or deactivated via a user profile assigned to the vehicle (1). [3] Method according to claim 1 or 2, characterized by , that it is recorded whether at least one vehicle occupant is carrying an active implanted medical device (AIMD) and the procedure is then carried out if at least one vehicle occupant with an AIMD has been detected. [4] Control unit (40) for controlling at least one electrical device (20, 30) supplied via an on-board electrical system (10) of a vehicle (1), characterized by that the control unit (40) is configured to perform a method according to one of the preceding claims. [5] Vehicle (1) with at least one control unit (40) and at least one electrical device (20, 30) supplied via an on-board network (10), characterized by, that the control unit (40) is configured to perform a method according to one of claims 1 to 3.

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