How to monitor an onboard network in a vehicle
By precisely determining voltage reduction and disconnecting non-safety-related equipment in in-vehicle networks, the method ensures reliable power supply to safety-critical components, enhancing availability and comfort.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2023-03-06
- Publication Date
- 2026-07-24
Smart Images
Figure 0007894950000001 
Figure 0007894950000002 
Figure 0007894950000003
Abstract
Description
Technical Field
[0001] The present invention relates to a method for monitoring an in-vehicle network of a motor vehicle based on the field of the independent claims.
Background Art
[0002] From DE102018212369A1, a method for monitoring the energy supply in a motor vehicle is known. In this case, within a partial in-vehicle network, at least one energy storage device supplies energy to a plurality of preferably safety-related consumer devices. At least one measured quantity of the energy storage device and / or at least one of the at least one consumer device is captured, and at least one cable harness model representing the partial in-vehicle network is provided. A parameter estimator is provided for estimating at least one characteristic quantity of the cable harness model using the measured quantity.
[0003] From DE10201821277A1, a method for monitoring the in-vehicle network of a motor vehicle is known. In this regard, it is determined by simulation which safety stop scenarios are available in the respective battery state and in-vehicle network state. Furthermore, corresponding measures within the in-vehicle network are proposed, and an analysis of the direct impact of this measure on the availability of various scenarios is determined.
[0004] From DE102020212414A1, a method for monitoring an onboard network of a vehicle is known, in which at least one safety-related consumer and possibly additional consumer devices are supplied by one energy storage device, and at least one onboard network model is provided that represents the safety-related consumer device, corresponding wiring with assigned wiring resistance, and connections to the energy storage device, and includes the following steps: providing a current or power profile that is expected to be required for a particular operation of the vehicle involving at least one safety-related consumer device and may include the base load of at least one additional consumer device; determining predicted features of the energy storage device using this current or power profile; determining predicted features of the safety-related consumer device using the current or power profile expected to be applied to the safety-related consumer device, the assigned wiring resistance, and the predicted features of the energy storage device; and evaluating the predicted features of the safety-related consumer device. [Overview of the project]
[0005] The fundamental problem of this invention is to further enhance availability without significantly sacrificing user comfort, particularly with respect to onboard networks with high security requirements. This problem is solved by the features of the independent claims.
[0006] In contrast, the method based on the features of claim 1 has the advantage, on the one hand, that sufficient voltage supply for safety-related consumer equipment can be reliably guaranteed, in this case, based on a more precise determination of the degree of reduction, only the non-safety-related consumer equipment that is actually needed will be degraded or disconnected with considerable precision. In other words, the necessary, as few non-safety-related consumer equipment as possible will be disconnected from the energy supply. By more precisely determining the degree of reduction and the undervoltage, the measures taken can be precisely guaranteed to effectively reduce the similarly determined undervoltage as desired, and therefore ensure that safety-related consumer equipment will subsequently receive sufficient power again. Indeed, by individually determining the voltage drop at safety-related consumer equipment, tolerances for undervoltage can be better utilized, thereby minimizing potentially premature disconnection of non-safety-related consumer equipment or groups of consumer equipment, while still not jeopardizing the supply to safety-related consumer equipment. Thus, the availability of non-safety-related consumer equipment is improved.
[0007] In one useful variant, a trigger for disconnection or performance degradation is generated in at least one non-safety-related consumer device when the applied voltage to a safety-related consumer device falls below a certain duration threshold, preferably in the range of 1 ms to 500 ms. This allows for the appropriate voltage requirements to be individually adapted to each safety-related consumer device through the appropriate selection of thresholds or durations tailored to the specific characteristics of each device. It is precisely this appropriate time interval of 1 ms to 500 ms that makes it clear that this method is not useful for wiring protection, component protection, or part protection that may require overcurrent disconnection in time ranges of less than 10 μs. In contrast, the selected time range takes into account the increased safety requirements for safety-related consumer devices compared to classic onboard network interventions for voltage support exceeding 500 ms.
[0008] In one useful variant, the degree of voltage applied to safety-critical consumer equipment is intended to be determined from the supply voltage at the power distributor and the voltage drop in the wiring path between the power distributor and the safety-critical consumer equipment. By considering this voltage drop in the wiring path, particularly precise and accurate predictions of possible undervoltages can be achieved, thereby enabling the disconnection or degradation of non-safety-critical consumer equipment to be carried out accurately and precisely as needed. As a trend, non-safety-critical consumer equipment may be disconnected later than when disconnecting with a normal high safety margin.
[0009] In one useful variant, the voltage drop in the wiring path between the power distributor and the safety-related consumer equipment is intended to be determined by the resistance of each wiring path and the current flowing through the safety-related consumer equipment. In particular, a corresponding current measurement is generally already present in the power distributor based on safety functions such as overcurrent protection or similar, which allows for the simple determination of the voltage drop in the safety-related consumer equipment.
[0010] In one useful variant, the degree of reduction, particularly the current to be reduced, is determined by the resistance of the wiring path connecting the energy storage and the power distributor, and / or the internal resistance of the energy storage. Here again, the accuracy of performance degradation or disconnection is improved because additional features are taken into account, and these features may also change relatively strongly over the lifetime of the energy storage or onboard network.
[0011] In one useful variant, the number of non-safety-related consumer devices to be disconnected is determined based on the degree of reduction. Unlike typical systems, when there is a shortage, not all non-safety-related consumer devices are disconnected; instead, only the precise number needed is disconnected. This avoids disconnecting unnecessary non-safety-related consumer devices, further improving user comfort.
[0012] In one useful variant, the degree of reduction is determined such that the supply voltage is increased by at least the amount of the undervoltage. This precisely targeted increase effectively prevents unnecessary and excessive voltage increases, further improving comfort.
[0013] In one useful variant, the limit value changes depending on the duration for which the voltage applied to safety-critical consumer equipment remains below a corresponding limit value, and in particular, increases as the duration increases. This allows for accurate and early response to particularly critical situations involving prolonged periods below a sufficient supply voltage.
[0014] In one useful variant, the degree of reduction is determined using the resistance of the wiring paths to the energy storage and / or alternative energy sources, and / or the internal resistance of the energy storage, and / or depending on a predetermined degree of reduction, and / or depending on the resistance of the wiring paths to the energy storage and / or alternative energy sources determined by modeling or diagnostics, and / or depending on the internal resistance of the energy storage determined by modeling or diagnostics. This can further improve accuracy. In particular, by using models, the aging state of onboard network components can be predicted with relative accuracy and can serve as a basis for a correspondingly more accurate determination of the degree of reduction.
[0015] A useful variant features a mechanism that determines when the voltage applied to a safety-related consumer device reaches a limit, and then captures the duration during which the voltage remains below the limit. This captured duration is then compared to a duration assigned to the limit, and when the assigned duration is reached, a trigger is generated to initiate the disconnection or performance degradation of at least one non-safety-related consumer device. This allows for the simple implementation of a duration-dependent limit, which can then be easily adapted to each safety-related consumer device.
[0016] In one useful variant, the degree of voltage applied to at least safety-related consumer equipment is intended to be determined by measuring this voltage at the safety-related consumer equipment, and / or by using the current flowing through the safety-related consumer equipment, and / or by measuring the supply voltage, and / or by considering the resistance of the wiring path between the power distributor and the safety-related consumer equipment, particularly the worst-case value of the resistance or the resistance estimated by a model, and / or depending on the worst-case value of the voltage drop across the resistance. On the one hand, the accuracy of the assessment can be further improved by appropriate measures such as measuring the voltage there at the safety-related consumer equipment or measuring the current flow through the safety-related consumer equipment. On the other hand, specific worst-case values can further simplify the determination. By also using a model for determining the voltage at safety-related consumer equipment, a corresponding aging state of onboard network components can be represented with high reliability. The accuracy of the determination is improved.
[0017] In one useful variant, the trigger and / or undervoltage determination is performed by the safety-related consumer, and / or the safety-related consumer transmits the trigger and / or undervoltage and / or the voltage drop measured by the safety-related consumer, particularly to the power distributor. This allows for fast and accurate assessment to be performed already within the safety-related consumer, which already has high computing power, and frees the power distributor from this role. Communication volume can also be reduced, as a suitable disconnection signal is sent only when an undervoltage is imminent, precisely targeting the objective.
[0018] In one useful variant, the selection of non-safety-related consumer devices to be disconnected or degraded is based on the current flowing through each device, with particular consideration given to disconnecting or degrading non-safety-related consumer devices with current flows exceeding the maximum current flow or a certain limit. This ensures that the disconnected non-safety-related consumer devices actually cause the desired voltage boost. Furthermore, this proposed measure achieves the requirement to disconnect only a small number of truly necessary non-safety-related consumer devices.
[0019] In one useful variant, the intention is to disconnect non-safety-related power consumption devices until a certain reduction level is reached. This allows for particularly simple implementation of the selection and ensures that the desired voltage boost is achieved.
[0020] In one useful variant, the current flowing through each non-safety-related consumer device is linked to a weighting coefficient specific to that device, and the linked values are intended to be used to select which non-safety-related consumer devices should be disconnected or degraded. Particularly useful, each non-safety-related consumer device is assigned a weight or priority value, and the selection of which consumer devices should be disconnected or degraded is intended to be made by optimizing the linked weights or priorities. To minimize the loss of user comfort, these consumer devices may be given different priorities through appropriate weighting.
[0021] Further useful variations will become apparent from further dependent claims and descriptions of the invention. [Brief explanation of the drawing]
[0022] [Figure 1] This diagram shows an onboard network equipped with a power distributor. [Figure 2]FIG. 0 shows an exemplary alternative embodiment of an on-board network with a power distributor and further distributors. [Figure 3] FIG. 3 is a block diagram for implementing various sub-processes. [Figure 4] FIG. 6 is an exemplary voltage-time graph having an under-voltage range of attribution. DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention is schematically illustrated based on one exemplary embodiment and will be described in detail below with reference to the drawings. FIG. 1 shows a partial on-board network including a power distributor 18, especially within a motor vehicle. The power distributor 18 is supplied with energy via an energy storage device 12, especially a battery. For this purpose, the energy storage device 12 is connected at least partially to a power transmission rail 14 running within the power distributor 18. A resistance Rb is suggested between the power distributor 18 and the energy storage device 12, and the resistance Rb represents the resistance in the conductor to the energy storage device 12, especially the battery. For a possible redundant supply in the case of the power distributor 18, the power transmission rail 14 of the power distributor 18 can be connected to a further energy supply at another inlet, which is suggested in this exemplary embodiment by providing a DC voltage converter 22. The DC voltage converter 22 is connected to a further partial on-board network that can include, for example, a higher or lower or similar voltage level. A resistance Rdc is also schematically suggested between the power distributor 18 and the DC voltage converter 22, and the resistance Rdc represents the resistance in the conductor from the power distributor 18 to the DC voltage converter 22.
[0024] The power distributor 18 is connected to n safety-related consumer devices 16.1, 16.2, ..., 16.n and m non-safety-related consumer devices 17.1, 17.2, ..., 17.m. These safety-related consumer devices 16.n can be made particularly safe, for example, against overcurrent, by switching means not shown for clarity. Each non-safety-related consumer device 17.m is controllable by switching means 19 (19.1, 19.2, ..., 19.m), and can, in particular, be disconnected or have their performance degraded. These switching means 19 are located within the power distributor 18. The switching means 19 are preferably semiconductor switches, such as MOSFETs. Within the power distributor 18, the voltage U on the transmission rail 14 is measured. Furthermore, current measurements are performed within the power distributor 18. In this exemplary embodiment, each current I 16.n flowing through each safety-related consumer device 16.n is captured. Optionally, each current I17.m flowing through each non-safety-related consumer device 17.m may be captured. Optionally, the voltage U16.n applied to each safety-related consumer device 16.n may be measured, in particular, relative to earth or ground GND. The determined or measured applied voltage U16.n may be sent, depending on the location of the evaluation, to, for example, a power distributor 18 or further control equipment, via a communication system, such as a bus system like a CAN bus. Alternatively, the evaluation may be performed on the safety-related consumer device 16.n itself.
[0025] Resistors R16.1, R16.2, ..., R16.n are shown between the power distributor 18 and each of the safety-related consumer devices 16.n, respectively, and these resistors represent the resistance of each wiring path between the power distributor 18 and each of the consumer devices 16.n. Resistors R17.1, R17.2, ..., R17.m are shown between the power distributor 18 and each of the non-safety-related consumer devices 17.m, respectively, and these resistors represent the resistance of each wiring path between the power distributor 18 and each of the non-safety-related consumer devices 17.m.
[0026] The energy storage device 12 may be provided with sensors, not shown, preferably battery sensors, to capture further characteristic quantities of the energy storage device 12. In this sensor, for example, based on the state quantities of the energy storage device 12 and the model of its attribution, corresponding characteristic quantities of the energy storage device 12, such as the internal resistance Ri, the state of charge SOC, or the like, can be determined. The consumer device 16 related to safety is a special consumer device with high requirements or high protection requirements, and generally, it is referred to as the consumer device 16 related to safety. This is, for example, an electric steering and / or brake system as an example of a component that must be supplied absolutely in order to guarantee the vehicle's operation and / or braking in case of a defect.
[0027] The power distributor 18 also has corresponding processing means, not shown in detail, for example a microcontroller, to store or evaluate the captured quantities. The microcontroller can not only control the corresponding switching means 19 (or the switching means not shown specifically for protecting the consumer device 16 for the consumer device 16 related to safety). Instead, the evaluation may be performed by another control device. <{
[0028] The consumer devices 16 supplied by the power distributor 18, especially the consumer devices 16 with high requirements regarding protection requirements, may include, for example, vehicle functions related to safety, such as brakes, steering, etc. Generally, the consumer devices 16 related to safety are, for example, consumer devices that are necessary for maintaining a certain emergency function and are particularly valuable for protection. Not only the aforementioned functions such as steering and brakes, but also functions that should continue to function well if possible after an accident, such as restraint systems, closing systems for opening and closing vehicle doors, such as emergency call systems for transmitting electronic emergency calls, sliding roof functions, lighting, or the like.
[0029] Consumer devices 17.m that are not related to safety are typically comfort consumer devices. Comfort consumer devices 17.m can be divided into main and subgroups depending on their application, and thus can be grouped (see alternative exemplary embodiments based on Figure 2 with further distributors 50, 52). Such consumer devices 17 do not feature high importance to safety or feature relatively low requirements regarding protection requirements.
[0030] The exemplary embodiment based on Figure 2 differs from the exemplary embodiment based on Figure 1 in that further distributors 50 and 52 are connected to the power distributor 18, and these further distributors 50 and 52 can control the exemplary further consumer devices 16.k, 17.l, and 17.j, respectively. Distributor 50, to which at least one safety-related consumer device 16.k is connected, is supplied with a corresponding current I16.v from the power distributor 18 via wiring with wiring resistance R16.v. In addition, a further distributor 52 is provided, through which only a non-safety-related consumer device 17.j, which is shown as an example only in this exemplary embodiment, can be supplied and disconnected via corresponding switching means 19.j. This further distributor 52 is supplied with a corresponding current I17.v from the power distributor 18 via wiring with wiring resistance R17.v. The assigned non-safety-related consumer device 17.j is supplied with current I17.j.
[0031] In this regard, the sub-process described below can be distributed to various control devices. This allows the disconnection of non-safety consumer devices 17.m to be triggered in other distributors 50, 52 via corresponding switching means 19.l, 19.j. Signals 40 for disconnecting consumer devices 17.l, 17.j can be transmitted via a communication bus, and commands can also be issued in independent control devices, such as so-called vehicle computers. Also, if a voltage dU is applied to a safety consumer device 16.k supplied by distributor 50, this distributor 50 can also suggest to power distributor 18 the disconnection of a corresponding non-safety consumer device 17.
[0032] As an example, in this exemplary embodiment, a battery or storage cell is described as a possible energy storage device 12. However, other energy storage devices suitable for the present problem, such as inductive or capacitive-based energy storage devices, fuel cells, capacitors, or similar devices, may also be used instead.
[0033] The time range for the isolation of the consumer device 17 to be disconnected is between 1 ms and 500 ms. This method is not useful for wiring protection, component protection, or part protection, and is therefore incomparable to overcurrent disconnection in time ranges of less than 10 μs. In classical onboard networks, energy management adjustment interventions in time ranges exceeding 500 ms may be expected. In some cases, it must be ensured that the quantity to be evaluated is quickly captured and / or quickly communicated to an evaluation unit, such as a power distributor 18.
[0034] In Figure 3, different blocks 30, 34, and 38 are schematically shown along with their input and output quantities. Multiple of the above quantities are fed into the undervoltage detection 30. These are the current I16.n through each safety-related consumer device 16.n and / or the voltage U in the transmission rail 14 and / or the resistors R16n of one or more wiring paths to each safety-related consumer device 16.n and / or the resistors R17.m of one or more wiring paths to each non-safety-related consumer device 17.m. Based on these, the undervoltage detection 30 determines at least one trigger 32 and / or the undervoltage dU, as described below. The calculation of the undervoltage detection 30 may be performed within the power distributor 18, or within each consumer device 16.n, 17.m, in particular within the safety-related consumer device 16.n, but also within the non-safety-related consumer device 17.m. For undervoltage detection 30, the following process steps may be used individually or in combination. The degree of voltage U16.n in each safety-related consumer device 16.n can be determined by different approaches as follows:
[0035] In the first option, the voltage U at the power transmission rail 14 is captured. To account for the voltage drop due to each resistor R16.n in the wiring path to each safety-related consumer device 16.n, a predefined voltage Uw representing the worst-case scenario is subtracted from the voltage U at the power transmission rail 14. This predefined voltage Uw is the worst-case experience value that must be accepted in the worst-case scenario. Thus, the voltage U16.n at each safety-related consumer device 16.n can be estimated as follows. U16.n=U-Uw (1)
[0036] In one further option, to estimate the degree of voltage drop U16.n at safety-related consumer equipment 16.n, the measured voltage U at the power transmission rail 14, the measured current I16.n through the safety-related consumer equipment 16.n, and a fixed resistance value R16.n_w representing the worst case are taken into consideration. From the voltage U at the power transmission rail 14, the voltage drop along the wiring path is calculated based on Ohm's law, using the worst-case estimate of the wiring resistance R16.n_w and the current flow I16.n through each wiring. U16.n = U - I16.n * R16.n_w (2)
[0037] In one further option, to estimate the degree of voltage drop U16.n at safety-related consumer equipment 16.n, the measured voltage U at the transmission rail 14, the measured current I16.n through the safety-related consumer equipment 16.n, and the respective wiring resistance R16.n_d estimated within the framework of the model are taken into consideration. From the voltage U at the transmission rail 14, the voltage drop along the wiring path is calculated based on the diagnostic function of the wiring resistance R16.n_d (as described, for example, in DE102018212369A1 and fully related to that disclosure) and the current flow I16.n through this wiring. U16.n = U - I16.n * R16.n_d (3)
[0038] In one further alternative exemplary embodiment, the voltage U16n applied to the safety-related consumer devices 16.n is measured directly within each consumer device 16.n itself and communicated to the power distributor 18 via a communication interface (e.g., CAN). U16.n = U16.n via communication means (4)
[0039] In another option, the degree of the voltage U16.n applied to the safety-related consumer devices 16.n can be evaluated within each consumer device 16.n itself. When it is recognized that an undervoltage dU is imminent, a function built into each consumer device 16 sends a trigger 34 and / or the undervoltage dU to the power distributor 18. In other words, undervoltage recognition 30 is performed within the consumer device 16.n instead of within the power distributor 18. U16.n = U16.n within consumer device 16 (5)
[0040] These various methods for determining the degree of voltage U16.n applied to safety-related consumer equipment 16.n can be used alternatively (individually), but at least two, but also more, alternative determinants can be used for mutual likelihood confirmation. In the case of a low-likelihood result, appropriate warning notices or countermeasures may be initiated.
[0041] The durations T1, T2, and T3 of the applied calculated or measured voltage U16.n are important for recognizing that an undervoltage dU is imminent and for generating a trigger signal 32 that suggests disconnecting 40 or degrading the performance of a non-safety-related consumer device 17. According to Figure 4, this is represented by a dynamic voltage limit Ug, that is, the voltage limit Ug increases as the duration T of being below the voltage limit Ug increases. In the exemplary embodiment based on Figure 4, the increase in the voltage limit Ug as the duration T increases is stepwise. However, in principle, other relationships between the limit value Ug and the maximum allowable duration T for each limit value Ug, such as a relationship in the form of a continuously, i.e., constantly increasing function, can also be implemented. The durations T or T1, T2, and T3 represent the maximum duration for which the voltage U16.n of the safety-related consumer equipment 16.n must not fall below the assigned limit values Ug or Ug1, Ug2, and Ug3, otherwise an undersupply or failure of the safety-related consumer equipment 16.n will be imminent. From duration T1 onward, the limit value Ug has a first value Ug1 and remains constant until a further duration T2. Duration T1 is, for example, in the range of about 0.5 ms, and the further duration T2 is, for example, 10 ms. The first limit value Ug1 has a minimum value, and with respect to the supply voltage (12V in this exemplary embodiment), this first limit value Ug1 takes a value of, for example, about 50% of the supply voltage. Absolutely, the first limit value Ug1 is, for example, in the range of 6V to 7V, and is 6.4V in this exemplary embodiment. After a duration T2 (e.g., 10 ms), the limit value Ug rises to a value Ug2, which is 70% of the supply voltage, and is absolutely exemplary, as shown in Figure 3, for example, 8.6V or in the range of 8-9V. After a duration T2, the second limit value Ug2 remains constant until a duration T3. After a duration T3 (e.g., 100 ms), the limit value Ug rises to a value Ug3, which is 80% of the supply voltage, and is absolutely exemplary, as shown in Figure 3, for example, 9.6V or in the range of 9-10V. After a duration T3, the third limit value Ug3 also remains constant.
[0042] For duration T1, trigger 32 is generated when the determined voltage U16.n is about to fall below the first limit value Ug1. For duration T2, trigger 32 is generated when the determined voltage U16.n is about to fall below the second limit value Ug2. For duration T3, trigger 32 is generated when the determined voltage U16.n is about to fall below the third limit value Ug3. When the determined voltage U16.n falls below one of the limit values Ug, the timer starts at this point. Trigger 32 is generated as soon as the duration T assigned to the fallen limit value Ug is reached. For this fallen limit value Ug, the undervoltage dU is determined as described below.
[0043] The voltage difference or undervoltage dU is calculated (dU = Ug - U16.n) based on the voltage U16.n at each confirmed or measured safety-related consumer device 16.n and the dynamic voltage limits Ug; Ug1, Ug2, Ug3 based on, for example, Figure 3. In this calculation, the limit value Ug closest to the voltage drop U16.n at the confirmed safety-related consumer device 16.n is selected. For example, if the voltage U16.n is 6V, the undervoltage dU for the closest limit value Ug1 (Ug1 = 6.4V) is 0.4V. If the voltage U16.n is, for example, 8V, the undervoltage dU for the closest limit value Ug2 (Ug2 = 8.6V) is 0.6V, and so on.
[0044] This voltage difference or undervoltage dU is used as an input to block 34 for estimating the current Ir that should be disconnected. The process steps or block 34 for estimating the degree of reduction, for example, the current Ir that should be disconnected or reduced, are described in more detail below. In order to stabilize the voltage U (increase by dU) and to comply with the voltage and time limits of safety-related consumer equipment 16.n, one or more non-safety-related consumer equipment 17.m must be disconnected. The number of non-safety-related consumer equipment 17.m that must be disconnected is determined on the basis of the degree of reduction (e.g., the current 36 that should be disconnected) Ir. The amount of current Ir that must be reduced in order to increase the supply voltage U by dU can be derived by one of the sub-processes described below.
[0045] In other words, one possible option is to implement a fixed value for the amount of reduction or the current Ir to be cut off. When trigger 32 is activated, the current Ir defined in relation to it must be cut off. Ir=constant (1)
[0046] In one further option, the reduction degree Ir is calculated using the undervoltage dU determined by the undervoltage recognition 30, the total resistance Rb of the entire path from the energy storage 12 to the input of the power distributor 18, and the resistance Ri of the energy storage 12, particularly the internal resistance of the battery, up to earth or ground. The above resistances Rb and Ri may be based on known resistances or corresponding estimates at the beginning of the life cycle. If the energy storage 12 is not provided as a power source or if the energy storage 12 is being charged, the current in the direction of the DC voltage converter 22 must be reduced. Thus, the current to be reduced Ir is determined as follows: Ir = dU / (Rb + Ri) or Ir = dU / Rdc (2)
[0047] Based on the undervoltage dU calculated by the undervoltage recognition 30, the resistance Rdc_d of the cable assembly of the conductor from the DC voltage converter 22 determined by the diagnosis, and / or the resistance Rb_d of the cable assembly of the conductor to the energy storage 12 determined by the diagnosis, and / or the internal resistance Ri_d of the energy storage 12 determined by the diagnosis, the degree of reduction, for example, the current Ir to be cut off, is calculated in a further alternative procedure. Ir=dU / (Rb_d+Ri_d) or Ir=dU / Rdc_d (3)
[0048] In one further option, the reduction degree Ir may be set by energy management to adequately stabilize the voltage. Ir = Ir via communication system from energy management (4)
[0049] A further block 38 is responsible for selecting non-safety-related consumer devices 17.m to be disconnected. For this process step 38, the current Ir to be disconnected from the trigger 32 and / or block 34 and / or the respective current I17.m flowing through each non-safety-related consumer device 17.m are supplied. That is, given that the trigger 32 (from block 30) and the current Ir to be disconnected (from block 34) are known, one of the process steps described below is used to disconnect the precisely determined non-safety-related consumer devices 17.m. Disconnection is performed via corresponding disconnection signals 40.1, 40.2, ..., 40.m that can control each of the said switching means 19m. In this case, the consumer devices 17.m may be disconnected immediately or in stages. In the case of staged disconnection, after the disconnection of the consumer(s) of consumer devices, a defined system response is awaited, and new or further disconnections of non-safety-related consumer devices 17.m are performed if necessary or in the event of non-compliance with voltage requirements. The system response could be an increase in voltage U on the transmission rail or a signal from a system located higher up.
[0050] In one configuration, all non-safety-related consumer devices 17.m can be disconnected. When a corresponding trigger signal 36 is generated and transmitted by the undervoltage detection 30, all non-safety-related consumer devices 17.m are disconnected. The current Ir to be reduced is not required as an input quantity.
[0051] In a further alternative form, this is done based on the maximum current flowing within each non-safety-related consumer device 17.m. That is, first, the non-safety-related consumer device 17.max with the maximum current flow I17.max is disconnected. This is continued until the current Ir to be reduced is reached.
[0052] In a further alternative configuration, the current I17.m flowing through non-safety consumer devices 17.m can be multiplied by a constant or dynamic weighting coefficient, and in proportion to this weighting number, the devices can be disconnected until at least the current Ir to be reduced is reached. The weighting number may be derived independently of the current I17.m. This weighting allows for the optimal selection of consumer devices 17.m to be disconnected, thereby achieving the best balance between the current Ir to be disconnected and the loss of function of each non-safety consumer device 17.m. For this purpose, weighting methods based on static or dynamic values, or based on the current or state of onboard network components, may be used. In this regard, the non-safety consumer devices 17.m to be disconnected or degraded can be selected, for example, by an optimization method (e.g., an optimization problem: binary linear programming), where each consumer device path is assigned a weight, which weights the impact of the current I17.m in each consumer device path on the system. Firstly, the condition must be met that the total current (I17.m) of the disconnected consumer devices 17.m must reach at least the reduction level Ir. As an optimization goal for optimized consumer device disconnection, while adhering to the above reduction conditions, for example, the minimum total priority value of non-safety consumer devices 17.m may be taken into consideration (the higher the priority of non-safety consumer devices 17.m, the higher the corresponding priority value).
[0053] In a further alternative configuration, a higher-level vehicle system provides a group of disconnectable consumer devices 17.m in accordance with the rules. This group of disconnectable consumer devices 17.m is then disconnected when performing its function. Alternatively, a corresponding group of consumer devices 17.m may be disconnected.
[0054] Disconnected non-safety consumer equipment (17.m) must be reconnected according to specific standards. Various standards may be used in this regard. In one form, a reconnection attempt may be made after a predetermined time. For example, if the reconnection attempt fails after x seconds, i.e., a new disconnection occurs, k further reconnection attempts may be made. Alternatively, an error message may be sent. The reconnection attempts may be aborted.
[0055] As a further alternative criterion, it is determined whether the voltage U remains stable for a defined time. For example, if the voltage U is greater than a threshold Ug of, for example, 11V for x seconds, then a non-safety-related consumer device 17.m that was previously disconnected may be connected.
[0056] As a further alternative criterion, reconnection may occur after communication with energy management. The vehicle-wide energy management or equivalent vehicle system may propose reconnection of non-safety-related consuming devices via a communication system, such as a CAN bus. Connections may be made individually, in interaction with each other, and / or in groups.
[0057] Within the framework of one further alternative criterion, disconnected consumer equipment 17.m may be reconnected based on current storage capacity. This function continuously calculates the minimum current storage capacity required to reconnect non-safety consumer equipment 17.m to the energy supply. Whether non-safety consumer equipment 17.m is reconnected is determined based on settings by the vehicle system, such as within the framework of energy management, and / or based on a pre-set current value I17.m_v for each consumer equipment 17.m, and / or based on a value dynamically calculated based on past consumer equipment current consumption, and / or in a similar manner.
[0058] The aforementioned function is not limited to a specific voltage level U (e.g., 12V in this exemplary embodiment) within the energy onboard network. The aforementioned method has an interface, not explicitly shown, to energy management to send at least one piece of feedback information about disconnected non-safety-related consuming equipment 17.m. In addition, communication or configuration from a higher-level vehicle system (e.g., energy management as described in the Attributable Partial Process) can also be imagined. Based on the required execution speed (between 1ms and 500ms), energy management cannot perform this function on its own. Therefore, configuration parameters must be provided to the power distributor 18 before the function is executed, or only upon reconnection after a voltage shortage occurs.
Claims
1. A method for monitoring an onboard network of an automobile, wherein at least one power distributor (18) is provided, and a supply voltage (U) is supplied to at least one safety-related consumer device (16) via the power distributor (18), and a non-safety-related consumer device (17) is supplied via the power distributor (18), and the power distributor (18) is supplied by at least one energy storage device (12), and the degree of the voltage (U16.n) applied to at least the safety-related consumer device (16.n) is determined, and Based on this, in a monitoring method in which the undervoltage (dU) in the safety-related consumer device (16.n) is determined depending on a limit value (Ug), the degree of reduction (Ir) of disconnection or performance degradation of at least one non-safety-related consumer device (17.m) necessary to raise the voltage (U16.n) applied to the safety-related consumer device (16.n) is determined depending on the undervoltage (dU), and based on the degree of reduction (Ir), the non-safety-related consumer device (17.m) to be disconnected or performance-degraded is selected. A monitoring method characterized in that when the voltage (U16.n) dropping in the safety-related consumer device (16.n) reaches or is about to reach the limit value (Ug) for a specific duration (T1, T2, T3) in the range of 1 ms to 500 ms, a trigger (32) for disconnection or performance degradation of at least one of the non-safety-related consumer devices (17.m) is generated.
2. A method for monitoring an onboard network of an automobile, wherein at least one power distributor (18) is provided, and a supply voltage (U) is supplied to at least one safety-related consumer device (16) via the power distributor (18), and a non-safety-related consumer device (17) is supplied via the power distributor (18), and the power distributor (18) is supplied by at least one energy storage device (12), and the degree of the voltage (U16.n) applied to at least the safety-related consumer device (16.n) is determined, and Based on this, in a monitoring method in which the undervoltage (dU) in the safety-related consumer device (16.n) is determined depending on a limit value (Ug), the degree of reduction (Ir) of disconnection or performance degradation of at least one non-safety-related consumer device (17.m) necessary to raise the voltage (U16.n) applied to the safety-related consumer device (16.n) is determined depending on the undervoltage (dU), and based on the degree of reduction (Ir), the non-safety-related consumer device (17.m) to be disconnected or performance-degraded is selected. The monitoring method is characterized in that the limit value (Ug) changes depending on the duration (Ti) during which the degree of voltage (U16.n) drop in the safety-related consumer device (16.n) is below a corresponding limit value (Ug), and increases as the duration (Ti) increases.
3. A method for monitoring an onboard network of an automobile, wherein at least one power distributor (18) is provided, and a supply voltage (U) is supplied to at least one safety-related consumer device (16) via the power distributor (18), and a non-safety-related consumer device (17) is supplied via the power distributor (18), and the power distributor (18) is supplied by at least one energy storage device (12), and the degree of the voltage (U16.n) applied to at least the safety-related consumer device (16.n) is determined, and Based on this, in a monitoring method in which the undervoltage (dU) in the safety-related consumer device (16.n) is determined depending on a limit value (Ug), the degree of reduction (Ir) of disconnection or performance degradation of at least one non-safety-related consumer device (17.m) necessary to raise the voltage (U16.n) applied to the safety-related consumer device (16.n) is determined depending on the undervoltage (dU), and based on the degree of reduction (Ir), the non-safety-related consumer device (17.m) to be disconnected or performance-degraded is selected. A monitoring method characterized in that it is determined when the degree to which the voltage (U16.n) drops in the safety-related consumer device (16.n) reaches the limit value (Ug), and after the limit value (Ug) is reached, the duration (T) during which it is below the limit value (Ug) is captured, the captured duration (T) is compared with the duration (Ti) assigned to the limit value (Ug), and when the assigned duration (Ti) is reached, a trigger (32) is generated to initiate the disconnection or performance degradation of at least one non-safety-related consumer device (17.m).
4. A method for monitoring an onboard network of an automobile, wherein at least one power distributor (18) is provided, and a supply voltage (U) is supplied to at least one safety-related consumer device (16) via the power distributor (18), and a non-safety-related consumer device (17) is supplied via the power distributor (18), and the power distributor (18) is supplied by at least one energy storage device (12), and the degree of the voltage (U16.n) applied to at least the safety-related consumer device (16.n) is determined, and Based on this, in a monitoring method in which the undervoltage (dU) in the safety-related consumer device (16.n) is determined depending on a limit value (Ug), the degree of reduction (Ir) of disconnection or performance degradation of at least one non-safety-related consumer device (17.m) necessary to raise the voltage (U16.n) applied to the safety-related consumer device (16.n) is determined depending on the undervoltage (dU), and based on the degree of reduction (Ir), the non-safety-related consumer device (17.m) to be disconnected or performance-degraded is selected. A monitoring method characterized by multiplying the current flowing through each of the aforementioned non-safety consumer devices (17.m) by a weighting coefficient specific to each of the aforementioned non-safety consumer devices (17.m), and using the resulting weighting score to select the non-safety consumer devices (17.m) that should be disconnected or have their performance degraded.
5. The monitoring method according to claim 1, characterized in that the extent of the voltage drop (U16.n) in the safety-related consumer equipment (16.n) is determined from the supply voltage (U) in the power distributor (18) and the voltage drop in the wiring path between the power distributor (18) and the safety-related consumer equipment (16.n).
6. The monitoring method according to claim 5, characterized in that the voltage drop in the wiring path between the power distributor (18) and the safety-related consumer equipment (16.n) is determined by the resistance of each of the wiring paths (R16.n_w, R16.n_d) and the current (I16.n) flowing through the safety-related consumer equipment (16.n).
7. The monitoring method according to claim 1, characterized in that the reduction degree (Ir) is determined depending on the resistance (Rb) of the wiring path connecting the energy storage device (12) and the power distributor (18), and on the internal resistance (Ri) of the energy storage device (12).
8. The monitoring method according to claim 1, characterized in that the number of non-safety consumer devices (17.m) to be cut is determined depending on the degree of reduction (Ir).
9. The monitoring method according to claim 1, characterized in that the reduction degree (Ir) is determined such that the supply voltage (U) and / or the voltage (U16.n) applied to the safety-related consumer equipment (16.n) is increased by at least the amount of the undervoltage (dU).
10. The monitoring method according to claim 1, characterized in that the extent of the voltage (U16.n) applied to at least the safety-related consumer equipment (16.n) is determined by measuring the voltage at the safety-related consumer equipment (16.n), or by using the supply voltage (U) and the worst-case value (Uw) of the voltage drop at the resistance (R16.n) of the wiring path between the power distributor (18) and the safety-related consumer equipment (16.n), or by using the supply voltage (U), the current (I16.n) flowing through the safety-related consumer equipment (16.n) and the worst-case value of the resistance (R16.n_w), or by using the supply voltage (U), the current (I16.n), and the resistance value of the wiring path (R16.n_d).
11. The monitoring method according to 10, characterized in that the determination of the trigger (32) and / or the undervoltage (dU) is performed by the safety-related consumer device (16.n), and / or the safety-related consumer device (16.n) transmits the trigger (32) and / or the undervoltage (dU) to the power distributor (18).
12. The monitoring method according to claim 1, characterized in that the selection of non-safety consumer devices (17.n) to be disconnected or degraded is made based on the current flowing through each of the non-safety consumer devices (17.m), and the non-safety consumer device (17.m) having the maximum current flow is disconnected or degraded.
13. The monitoring method according to claim 1, characterized in that non-safety-related consumer equipment (17.m) is disconnected until the aforementioned reduction level (Ir) is reached.