DE10059949B4 - Method for operating an electronic assembly for a motor vehicle - Google Patents

Abstract

method for operating an electronic assembly (1) for a motor vehicle with an electrical system for power supply and one on this control signal towards activatable electrochemical energy source (3, 3.1, 3.2, ...), characterized in that the assembly in normal operation from the electrical system (10) with electrical energy is supplied for self-service operation in the event of a failure of the vehicle electrical system (10) however, the module (1) generates the control signal (s0) which the electrochemical energy source (3) activated.

Description

The The invention relates to a method for operating an electronic Assembly for a motor vehicle, in particular control unit of an occupant protection system, according to the generic term of claim 1.

Such an assembly is, for example, as a control unit of an occupant protection system of the DE 198 13 955 A1 refer to. The energy required to operate the module is thereby obtained from the electrical system of the motor vehicle and fed via a bus system to the individual control devices of the occupant protection devices. The control units have an autarkic capacitor as energy storage, the energy content is sufficient for a limited period of time for the intended operation of the controller.

For a series of applications, for example. Assemblies for safety-critical areas in the motor vehicle, in particular control devices of occupant protection devices, however autarky times of several seconds are required, which is relatively big and thus expensive autarky capacitors conditional. The same problem occurs for the provision of ignition energy in the occupant protection devices, since the to be provided Ignition energy as well size and expensive ignition capacitors requires.

In addition, the charging of the capacitors, regardless of whether autarky or firing capacitors charged during commissioning of the module often takes place via the same line data transmission. Because of this, the beats DE 197 51 910 C1 in addition to use an accumulator as an intermediate energy storage, which initially provides the energy when the system is turned on and is then slowly recharged from the electrical system. When the module is switched off, the energy stored in the ignition energy store is also preferably loaded back into the accumulator.

In particular, in occupant protection devices in motor vehicles, such as the DE 195 41 998 A1 can be seen, in which the data exchange with sensors and / or a central unit via a wireless data transmission medium, the ignition energy must be recovered from the data transmission medium, which with considerable effort, high energy losses and often unwanted strong interference to other modules or even the vehicle occupants connected is.

From the not previously published application DE 100 22 173 A1 In addition, a method for triggering occupant protection devices is to be found in which upon reaching a first stage of accident risk and / or accident severity first an indirect, not immediately triggering the occupant protection device leading trigger command is set, which withdrawn within a predetermined time by a cancel command can be.

In addition, for example, from the DE-OS 37 09 742 Thermal batteries known as activatable electrochemical energy sources for ammunition, missiles, etc. Thermal batteries are activatable energy sources in which a relatively high load voltage source is provided by thermoelectric reaction or as a result of the liquefaction of electrolytes and which are characterized by an extremely good long-term availability over many years. In addition, there are a number of other alternative activatable electrochemical energy sources.

From the DE 195 23 109 A1 For example, it is known to use a fuel cell for power supply instead of an alternator in a vehicle to allow a constant, independent of the engine speed and need-based energy supply via the vehicle electrical system. However, if the on-board power supply line is interrupted, the module can not continue to function analogously to the other wired wiring systems. If sufficient and therefore correspondingly large autarky capacitors are to be charged for a long autarchic time, considerable inrush current loads also occur when the power is supplied via the vehicle electrical system from a fuel cell. Hydrogen-based fuel cells are also currently not capable of long-term storage due to the volatilizing hydrogen. Fuel cells with recovery of hydrogen from other substances, in particular the elimination of fuel are extremely expensive, must also be refilled and also currently still have a non-negligible start-up reaction time.

From the DE 4201651 In addition, a self-ignition device for airbags is known, in which a thermoelectric battery is provided for emergency ignition upon reaching a critical temperature range.

The object of the invention is to present an alternative power supply for electronic assemblies in motor vehicles and particularly suitable method for operating this. These objects were achieved by the features of claim 1 ge solves.

basic idea is about to bring the electronic assembly for power an activatable to a control signal electrochemical energy source equip, which preferably directly on or in the Assembly is arranged in the vehicle and individually this If necessary, an assembly is supplied with energy. preferred meadow the electrochemical energy source consists of a plurality of individual activatable cells, so that either the power supply over a still longer Period, for temporally separate needs or even adapted to a different level of energy consumption is possible. In particular, should safety-critical electronic assemblies, in particular the ECUs of occupant protection devices or the central unit of the occupant protection system with such an activatable electrochemical energy source be equipped.

From Of particular importance is the individual assignment of the electrochemical Energy source to the modules also due to the possible individually optimized method for operating the electrochemical Energy source of the assembly, because so is one for the particular application needs-based release of energy possible.

One first procedure employed dealing with the operation of an electronic assembly in self-service, wherein the assembly in normal operation of an electrical system with electrical energy is supplied, in case of failure of the electrical system, however the electronic assembly generates the control signal which is the electrochemical Energy source activated. Preferably, in addition to the activatable electrochemical energy source in normal operation with intact Electrical system via the on-board network charged Autarkiekondensator provided in the Autarkiebetrieb in case of failure of the electrical system initially directly takes over the power supply and subsequently the electrochemical energy source is activated. Thereby can in particular, turn-on delay times some electrochemical energy sources bridges or these accordingly be designed simpler and thus cheaper.

Next The application in motor vehicles is basically also a transmission on airplanes, ships and similar means of transport, over one On-board network for energy supply, but only a limited Energiebereitbereitstellbarkeit about this Vehicle electrical system and in particular the risk of an electrical system interruption feature.

In Further developments of this method is the electrochemical energy source only activated if the autarky capacitor fails in case of failure of the electrical system tappable voltage drops below a predetermined minimum voltage or if the failure of the vehicle electrical system exceeds a predetermined period of time. In addition, you can additional Vehicle parameters, in particular the speed of the vehicle, recorded as well as compared with predetermined setpoints and the activation the electrochemical energy source in case of failure of the electrical system additionally in dependence be initiated by this setpoint comparison. This can in particular ensure that, for example, not unnecessarily when the vehicle is stationary, for example, when repairing the electrochemical Energy source is activated.

Furthermore In a further development, the assembly with sensors for recording a safety-critical condition, for example with distance sensors for determining an impending vehicle collision, impact sensors or acceleration sensors for detecting an accident from the Acceleration process, connected directly or via a central unit and the electrochemical energy source is activated only when a Failure of the electrical system during a safety critical condition occurs. The goal is always one possible needs-based activation of the electrochemical energy source and an avoidance of unnecessary Consumption of electrochemical energy sources, since even in multicellular Energy sources whose number and thus the number of possible Activations already limited for cost reasons is.

at electrochemical energy sources consisting of a plurality individually are on the control signal activated cells, is preferably initially on the control signal triggered a first still activatable cell of the electrochemical energy source and then monitored, whether the activated amount of energy is sufficient, for example based on the tapped voltage or by means of a timer. Possibly other cells are activated one after the other, if that is the case leading to activation Conditions, such as failure of the electrical system, certain vehicle parameters and / or safety-critical condition are present. Preferably the driver of the vehicle over informed the consumption of cells, at least when falling short a minimum reserve of cells warned.

A method again adapted according to the application is proposed for an electronic assembly in an occupant protection device in motor vehicles, in which the occupant protection device requires an amount of ignition energy to trigger and the data exchange with the sensors and / or the central unit via a low-energy, in particular for the transmission of the amount of ignition energy not or only with considerable effort suitable data transmission medium takes place. Radio waves or light waves as data transmission medium have considerable advantages due to the possibility of flexible distribution of the modules, but the disadvantage is the low efficiency in the energy transmission due to the high active losses. Therefore, it is proposed that the occupant protection device activate an electrochemical energy source to provide the amount of ignition energy to a trip command or trip ready command.

In occupant protection devices that form part of an occupant protection system according to the DE 100 22 173 A1 are in which upon reaching a first stage of accident hazard and / or accident severity first indirect, not immediately triggering the occupant protective device trigger command is set, an electrochemical energy source is provided with a plurality of individually activatable cells and the mediate trigger command each still activatable Cell activated. Thus, a needs-based energy supply in the first stage of accident risk and / or accident severity even before the immediate release possible. However, if due to the dangerous situation course of the indirect trigger command can be withdrawn, the occupant protection device is still available for subsequent dangerous situations, which can then be triggered from the remaining activatable cells of the electrochemical energy source.

The Invention will be described below with reference to embodiments and figures be explained in more detail. Brief description of the figures:

1 electronic assembly in a motor vehicle with a connection to the electrical system and an existing of several individually activatable cells electrochemical energy source for self-service operation in case of failure of the electrical system

2 electronic assembly in an occupant protection device with an electrochemical energy source as the ignition energy source

3 Flow sketch of the method for supplying power to an occupant protection device according to the principle of indirect trigger commands according to the DE 100 22 173 A1

The 1 shows an electronic assembly 1 in a motor vehicle with a connection to the electrical system 10 and an electrochemical energy source 3 , for supplying a load element 2 , About the electrical system 10 In normal operation, the voltage U from a vehicle battery is preferably also for further modules 11 provided.

The electronic assembly 1 has a control device 4 for the needs-based activation of the electrochemical energy source 3 on. The electrochemical energy source 3 consists in this preferred embodiment of several individually activatable cells 3.1 . 3.2 . 3.3 ... between the individual cells 3.1 . 3.2 . 3.3 ... the electrochemical energy source 3 and the control device 4 is a switch controllable by the latter via the cell selection signal sx 5 provided, each pointing to the next, still activatable cell. In 1 is just the cell 3.2 activated by the control signal s0. Below is the next cell that can still be activated 3.3 ,

In addition, the assembly in this embodiment has a self-sufficiency capacitor C, which in normal operation with intact electrical system 10 already from this electrical system 10 was charged. The autarky capacitor C has a relation to the vehicle electrical system voltage U by means of an up-converter 8th increased voltage Uc, which in this embodiment for the supply to the load element 2 again by means of a down converter 9 is lowered. Advantage of this increased voltage Uc on Autarkiekondensator C is on the one hand, the larger energy storage amount at the same capacity and also maintaining the operational readiness even when the voltage U drops on the electrical system 10 up to one for the operation of the boost converter 8th mandatory minimum voltage value. It is particularly advantageous, that of the electrochemical energy source 3 provided energy also via this boost converter 8th to supply the autarkic capacitor C, since the electrochemical energy source 3 Usually has no constant voltage, but a falling characteristic. By the up-converter 8th In this case, just so much energy is always supplied that a constant voltage Uc on Autarkiekondensator C arises, even if the voltage at the electrochemical energy source 3 already drops significantly below the voltage Uc on Autarkiekondensator C.

The control device 4 for the activation of the electrochemical energy source 3 or their individual cells 3.1 . 3.2 . 3.3 , .... detects a series of signals, depending on which will decide on the activation.

So the voltage U is at the electrical system 10 recorded to a failure of the electrical system 10 to recognize. Preferably, however, autarky capacitor C initially takes over the power supply directly until the electrochemical En ergiequelle 3 is active. The autarky capacitor C, however, only needs the turn-on delay of the electrochemical energy source 3 bridge and can therefore be designed significantly smaller.

In the advantageous development, however, in addition to or as an alternative to the voltage U at the vehicle electrical system 10 the tapped on the autarkic capacitor C voltage Uc from the control device 4 captured and the electrochemical energy source 3 activated only when the voltage Uc which can be picked off at the autarky capacitor C drops below a predetermined minimum voltage. Thus, smaller failures of the electrical system or voltage fluctuations can be bridged on this alone from the autarky capacitor C, without any ignition of the electrochemical energy source 3 he follows. This is important because there are only a limited number of cells 3.1 . 3.2 . 3.3 ... will be available, just for cost reasons. In addition, it is monitored whether the amount of activated energy is sufficient, that is, for example, the voltage at the autarky capacitor C again rises above the minimum voltage, and optionally further cells ( 3.3 , ...) are activated one after the other (see also 3 ).

Alternatively, the duration of a failure of the electrical system 10 be monitored. The electrochemical energy source 3 is only activated if the failure of the electrical system 10 exceeds a predetermined period of time, if necessary. After expiry of a further period each time a further cell.

In addition, however, other parameters may be taken into account to actually only in a truly existential emergency, the electrochemical energy source 3 to activate. So is provided, also additional vehicle parameters by means of sensors 6 , in particular the speed of the vehicle to detect and compare with predetermined setpoints. The electrochemical energy source 3 is activated only if a failure of the electrical system 10 during an overshoot or undershooting of the setpoints occurs, in the case of speed monitoring, for example, only from a vehicle speed of, for example, over 30 km / h, because below this range, a temporary failure of the assembly, such as an active power steering or a brake assist, still too no serious safety risks for the vehicle occupants leads, for example, the vehicle remains sufficiently steerable and braked by the driver.

In addition to such vehicle parameters can also complementary or alternative sensors 7 be provided for detecting a safety-critical condition, which are connected directly or via a central unit with the module, in particular an occupant protection device. The electrochemical energy source 3 only activated if a failure of the electrical system 10 occurs during a safety critical condition. As sensors 7 To detect a safety-critical condition, for example, distance sensors for detecting an impending vehicle collision, impact sensors or acceleration sensors for detecting an accident from the acceleration course are known, whose data are preferably in a central unit 7 treated, compared with each other and derived from the occurrence of a safety-critical condition. While the electrochemical energy source 3 in an assembly 1 So is activated for a steering or braking assistance in case of failure of the electrical system, for example, depending on the vehicle speed, this can be done in assemblies of occupant protection systems depending on the safety-critical condition.

Accordingly, the electrochemical energy source becomes 3 an assembly 1 for a steering or braking assistance must be activated more frequently than that of an occupant protection device, so that the number of individually activatable cells is adjusted accordingly. Of course, the energy content of each cell, if necessary, also the type of electrochemical energy source 3 adapted to the application. Also conceivable are different amounts of energy in the individual cells and an energy management, which selectively targets the cells according to the required amount of energy, ie, for example, not according to their order but according to their amount of energy.

The driver of the vehicle is concerned about the consumption of cells 3.1 . 3.2 . 3.3 , ... on a display 12 informed, at least when a minimum reserve quantity of cells warned.

A particularly adapted method of operating such an electronic assembly with electrochemical energy source 3 arises when used in an occupant protection system in motor vehicles, as in 2 will be shown. The data exchange between the occupant protection devices 21 and a central processing unit 20 for processing the sensor signals of the sensors 29 to record a safety-critical condition via a low-energy data transmission medium 23 , in particular by radio or light waves. In 2 points to the central unit 20 a radio transmitter 22 and the occupant protection device 21 a radio receiver 24 with receiving circuit 25 on.

Although it can be from the radio or light waves in the receiving circuit 25 In addition to the data to a limited extent energy can be obtained, but this amount of energy is often not enough for the triggering of the occupant protection devices 21 he demanded amount of ignition energy or the expenditure for a corresponding energy intake is very high. The from the data transfer medium 23 recoverable energy thus suffices for maintaining the normal diagnostic operation of the occupant protection device 21 , but not for their release. The occupant protection device 21 activated to provide the amount of ignition energy in a firing capacitor C _fire therefore on a tripping command or preferably a previous tripping ready command again an electrochemical energy source 3 , The actual triggering of the detonator 28 the occupant protection device 21 , For example, a gas generator of an airbag is carried out on a command from the central unit 20 from the receiving circuit 25 is detected, which then via signals SH and SL the switches 26 and 27 closes and so on again a boost converter 8th charged ignition capacitor C _fire over the detonator 28 shorts. It may also be a retransmission of data from the occupant protection device 21 to the central unit 20 done, for example, by load modulation on the radio receiver 24 via inductive coupling. Activation of additional cells 3.2 . 3.3 , ... preferably takes place analogously to the exemplary embodiment in FIG 1 as a function of the voltage at the ignition capacitor C _fire .

Is the occupant protection device 21 Component of an occupant protection system according to DE 100 22 173 A1 there is still a further advantageous embodiment, based on 3 is to be explained, in addition to the understanding of the disclosure of DE 100 22 173 A1 is referenced. Upon reaching a first stage L1 of the accident hazard and / or accident severity is first indirectly, not immediately to trigger the occupant protection device 21 leading trip command L1-On set, which can be withdrawn within a predetermined time window T of the central unit by a canceling command L1-Off again. For the ignition energy supply is now again an electrochemical energy source 3 with a plurality of individually activatable cells 3.1 . 3.2 . 3.3 , ... and at least on a first indirect tripping order L1-On into a still activatable cell, in 2 cell 3.2 , activated. Preferably, the voltage at the ignition capacitor C _{fire is also} detected and the next, still activatable cell 3.3 the electrochemical energy source 3 activated when the voltage Uc tapped off at the ignition capacitor C _fire drops below a predetermined minimum voltage Umin.

This is particularly in the embodiment of the occupant protection system according to the DE 100 22 173 A1 advantageous in which within the time window T by further indirect tripping commands L1-On the expiration of this time window T can be restarted in each case. So shows 3 First, the charging of the ignition capacitor C _fire by activating the cell 3.1 due to the first indirect trip command L1-On in t1. When the time window T in to + T / 2 is restarted, on the other hand, no further cell is activated, since the voltage Uc at the ignition capacitor C _{fire is} still above the minimum voltage Umin. At time t1, the redemption of the indirect triggering command takes place by means of the redemption signal L1-Off. If, at the time t2, an indirect trigger command L1-On occurs again, the next cell will be 3.2 activated, since the voltage Uc at the ignition capacitor C _fire has dropped below the predetermined minimum voltage Umin. The one from the cell 3.2 Although the amount of energy provided suffices for a series of repetitions of the indirect tripping command L1-On, it drops again below the minimum voltage Umin in t3. Accordingly, a next cell 3.3 This is preferably done immediately on sinking in t3, but possibly also on the next indirect triggering command L1-On (eg in t2 + 2T) is conceivable. If the severity of the accident reaches the second stage L2 in t4, then an immediate triggering command and thus ignition of the fuze takes place 28 the occupant protection device 21 from the ignition capacitor C _fire , as is illustrated by the correspondingly steep discharge of the ignition capacitor C _fire .

That is the result of the combination of 2 and 3 resulting embodiment of the application of the method of indirect trigger commands from the DE 100 22 173 A1 to a passenger protection system with low-energy data transmission medium (according to 2 ) is particularly preferred, however, the method of mediate trip commands from the DE 100 22 173 A1 be applied to other, especially on line occupant protection systems and the ignition energy supply from an electrochemical energy source are applied to the indirect trigger command accordingly. the combination of both developments to an embodiment is therefore not restrictive to understand.

Claims (12)

Method for operating an electronic assembly ( 1 ) for a motor vehicle with a vehicle electrical system for supplying energy and an electrochemical energy source which can be activated in response to this control signal ( 3 . 3.1 . 3.2 , ...), characterized in that the assembly in normal operation of the electrical system ( 10 ) is supplied with electrical energy for self-service operation in case of failure of the electrical system ( 10 ) but the assembly ( 1 ) generates the control signal (s0) which the electrochemical energy source ( 3 ) is activated. Process according to Claim 1, characterized in that the electrochemical energy source ( 3 ) from a plurality of individually activatable to the control signal (s0) cells ( 3.1 . 3.2 , ...) consists. Method according to claim 1, wherein besides the activatable electrochemical energy source ( 3 ) in normal operation with intact electrical system ( 10 ) via the electrical system ( 10 ) charged Autarkiekondensator (C) is provided, in Autarkiebetrieb in case of failure of the electrical system ( 10 ) first the autarky capacitor (C) directly takes over the power supply and subsequently the electrochemical energy source ( 3 ) is activated. Method according to Claim 3, in which the electrochemical energy source ( 3 ) is activated if, in the event of a failure of the electrical system ( 10 ) which can be tapped off the autarky capacitor (C) voltage (Uc) below a predetermined minimum voltage. Method according to Claim 4, in which the electrochemical energy source ( 3 ) is activated if the failure of the electrical system ( 10 ) exceeds a predetermined period of time. Method according to one of the preceding claims, in which additional vehicle parameters ( 6 ), in particular the speed of the vehicle, detected and compared with predetermined setpoints and the electrochemical energy source ( 3 ) is activated only if a failure of the electrical system ( 10 ) occurs when the setpoints are exceeded. Method for operating an assembly according to claim 6, in which the assembly ( 1 ) with sensors ( 7 ) is connected directly or via a central unit for detecting a safety-critical condition and the electrochemical energy source ( 3 ) is activated only if a failure of the electrical system ( 10 ) occurs during a safety critical condition. Method according to one of the preceding claims, in which, on the control signal (s0), first a first still activatable cell ( 3.2 ) of the electrochemical energy source ( 3 ), it is monitored whether the amount of activated energy is sufficient, if necessary, further cells ( 3.3 , ...) are activated one after the other. Method according to Claim 8, in which the driver of the vehicle is informed about the consumption of cells ( 3.1 . 3.2 . 3.3 , ...), at least if a minimum reserve quantity of cells is warned ( 12 ). Method according to Claim 1 or 2 in an occupant protection device ( 21 ) in motor vehicles, the occupant protection device ( 21 ) requires an amount of ignition energy to trigger and the data exchange with the sensors ( 29 ) and / or the central unit ( 20 ) via a low-energy data transmission medium ( 23 ), in particular by radio or light waves, in which the occupant protection device ( 21 ) for providing the amount of ignition energy in an ignition capacitor in response to a tripping order or tripping ready command the electrochemical energy source ( 3 ) is activated. Method according to Claim 1 or 2 in an occupant protection device ( 21 ) in motor vehicles, wherein a) the occupant protection device is part of an occupant protection system in which upon reaching a first stage (L1) the accident risk and / or accident severity first an indirect, not directly to trigger the occupant protection device ( 21 ) leading trip command (L1-On), which can be withdrawn within a predetermined time window (T) by the central unit by a cancel command (L1-Off), b) an electrochemical energy source ( 3 ) with a plurality of individually activatable cells ( 3.1 . 3.2 . 3.3 , ...) is provided and c) at least for a first indirect triggering command (L1-On) a still activatable cell ( 3.2 ) is activated. The method of claim 11, wherein the voltage is detected at the ignition capacitor and a next, still activatable cell ( 3.3 ) of the electrochemical energy source ( 3 ) is activated when the voltage (Uc) which can be picked off at the ignition capacitor (C) drops below a predetermined minimum voltage (Umin).