Method for Monitoring an Electronic Control Unit and Control Unit for a Motor Vehicle

Abstract

A method is specified for monitoring an electronic control unit for a motor vehicle. An electronic control unit with a monitoring circuit, which contains at least one sensor component, is provided. A measured value is recorded by means of the at least one sensor component, on the basis of which an actual value of a characteristic value representative for the thermal, mechanical and/or chemical loading of the control unit is determined and compared with a predetermined set-point value. A signal is emitted as a function of the result of the comparison. A device and a control unit are additionally specified.

Claims

1. A method for monitoring an electronic control unit for a motor vehicle, comprising: providing the electronic control unit, wherein the control unit has a control circuit which is constructed for controlling an operating function of the motor vehicle, and a monitoring circuit which contains at least one sensor component, recording a measured value by the at least one sensor component, determining an actual value of a characteristic value representative of thermal, mechanical and/or chemical loading of the control unit by the monitoring circuit on the basis of the recorded measured value, and comparing the actual value with a predetermined set-point value of the characteristic value, and emitting a signal by the monitoring circuit as a function of a result of the comparison.

2. The method as claimed in claim 1, wherein the characteristic value is representative of thermal, mechanical and/or chemical loading of the at least one sensor component, the control circuit is different from the monitoring circuit, and the control circuit has at least one electric or electronic component which is of the same type as the at least one sensor component and which is less sensitive with respect to the thermal, mechanical and/or chemical loading than the at least one sensor component.

3. The method as claimed in claim 1, wherein the characteristic value is representative of the thermal, mechanical and/or chemical loading of the at least one sensor component, the control circuit contains a plurality of similar electric or electronic components which together contribute to controlling the operating function of the motor vehicle and are connected to one another in such a manner that a failure of an individual component of the similar components does not impair the functionality of the control circuit for controlling the operating function, and the similar components constitute the sensor components and the failure of an individual component of the similar components or a failure of a portion of the similar components is detected for determining the actual value.

4. The method as claimed in claim 1, wherein the at least one sensor component contains at least one component from the following group: temperature sensor, acceleration sensor, vibration sensor, moisture sensor, sulfur sensor, and corrosion sensor.

5. The method as claimed in claim 1, wherein determining the actual value comprises evaluating at least one of the following parameters on the basis of the recorded measured value: temperature, a number and/or size of temperature fluctuations, maximum temperature, minimum temperature, a number of temperature cycles, a number and/or strength of mechanical impacts, a duration and/or intensity of mechanical vibrations, corrosion, sulfur concentration, and air humidity, and wherein the method further comprises determining the predetermined set-point value on the basis of a lifespan model of the at least one evaluated parameter.

6. The method as claimed in claim 1, further comprising: saving the actual value, recording a further measured value by the at least one sensor component following the comparison of the actual value with the set-point value, determining a new actual value of the characteristic value by the monitoring circuit on the basis of the recorded further measured value and the saved actual value and comparing the new actual value with the set-point value, and emitting a further signal by the monitoring circuit as a function of the result of the comparison of the new actual value with the set-point value.

7. The method as claimed in claim 1, wherein the signal is emitted during operation of the control unit for controlling the operating function of the motor vehicle by the control circuit.

8. The method as claimed in claim 1, wherein the emitted signal is a warning signal and is represented by an acoustic and/or optical indicating element, and/or is saved in a fault memory of the motor vehicle.

9. The method as claimed in claim 1, wherein the electronic control unit having the control circuit, the monitoring circuit and the at least one sensor component are part of a device.

10. An electronic control unit for a motor vehicle, comprising: a control circuit which is constructed for controlling an operating function of the motor vehicle; and a monitoring circuit which contains at least one sensor component, wherein the control unit is constructed and configured by the monitoring circuit for: recording a measured value by the at least one sensor component, determining an actual value of a characteristic value representative of at least one of thermal, mechanical and chemical loading of the control unit on the basis of the recorded measured value, comparing the actual value with a predetermined set-point value of the characteristic value, and emitting a signal as a function of the result of the comparison.

11. The control unit as claimed in claim 10, wherein the characteristic value is representative of at least one of thermal, mechanical and chemical loading of the at least one sensor component, and the control circuit is different from the monitoring circuit and has at least one electric or electronic component for each sensor component, which is of the same type as the respective sensor component and is less sensitive with respect to the at least one of the thermal, mechanical and chemical loading than the respective sensor component.

12. The control unit as claimed in the claim 11, wherein the monitoring circuit contains a plurality of sensor components, the sensor components being diverse sensor components which are connected in series in the monitoring circuit.

13. The control unit as claimed in claim 11, wherein the control unit comprises an application specific integrated circuit (ASIC) and the at least one sensor component is selected from the following group: a ceramic resistor which has a larger mass than the respective component of the control circuit, a resistor, an exposed metal surface of which is larger than that of the respective component of the control circuit, a resistor array and the component of the control circuit is a single resistor, a coil, an electrolytic capacitor, and a diode of the ASIC of the control unit, constructed with a reduced or omitted diffusion barrier compared with the respective component of the control circuit.

14. The control unit as claimed in claim 10, wherein the control circuit contains a plurality of similar electric or electronic components which are connected to one another in such a manner that together the similar electric or electronic components contribute to controlling the operating function of the motor vehicle and that a failure of an individual component of the similar components does not impair the functionality of the control circuit for controlling the operating function, and the similar components constitute the sensor components and the monitoring circuit is constructed for detecting a failure of an individual or a portion of the similar components for determining the actual value.

15. The control unit as claimed in claim 10, wherein the control circuit, the monitoring circuit and the at least one sensor component are arranged together in a housing of the control unit.

16. The control unit as claimed in claim 10, wherein the at least one sensor component contains at least one component from the following group: temperature sensor, acceleration sensor, vibration sensor, moisture sensor, sulfur sensor, and corrosion sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In the figures:

[0053] FIG. 1 shows a schematic sectional illustration of a control unit according to a first exemplary embodiment,

[0054] FIG. 2 shows a very schematized circuit diagram of a control unit according to a second exemplary embodiment,

[0055] FIG. 3 shows a very schematized circuit diagram of a control unit according to a third exemplary embodiment, and

[0056] FIG. 4 shows a very schematized circuit diagram of a control unit according to a fourth exemplary embodiment.

[0057] Identical, similar or identically acting elements are provided with the same reference numbers in the figures. In some figures, individual reference numbers and elements may be omitted to improve clarity. The figures and the size ratios, with respect to one another, of the elements illustrated in the figures are not to be considered as being to scale. Rather, individual elements may be illustrated at an exaggerated size for better representation and/or for better understanding.

DETAILED DESCRIPTION

[0058] FIG. 1 shows a control unit ECU according to a first exemplary embodiment in a very schematized sectional illustration.

[0059] The control unit ECU has a housing H, in which a printed circuit board PCB is arranged. A control circuit CC and a monitoring circuit SC, which are different from one another, are formed by means of conductor tracks on the printed circuit board PCB and further components. In the present case, the control circuit CC contains an electric or electronic component EC and a microcontroller C2. The monitoring circuit SC contains a further microcontroller C1 and a sensor component S1. During normal operation of the control unit, the sensor component S1 does not contribute to controlling an operating function of the vehicle. The control circuit CC with the component EC and the microcontroller C1, the monitoring circuit SC with the sensor component S1 and the microcontroller C2, and also the printed circuit board PCB are arranged in the common housing H. The functions of the two microcontrollers C1 and C2 may also be realized in a single microcontroller. In one design, the sensor component S1 is a sulfur sensor.

[0060] In an exemplary embodiment of a method for monitoring the electronic control unit ECU, a measured value M1 for the sulfur concentration is recorded by means of the sensor component S1. The recorded measured value M1 is calculated by means of the monitoring circuit SC using a value which results from earlier measurements of the sulfur concentration by means of the sensor component S1 and which is read in particular from an internal memory inM of the microcontroller C1. An actual value for the sulfur exposure of the control unit ECU is determined in this manner. The sulfur exposure is a characteristic value representative of a chemical loading of the control unit ECU.

[0061] The recorded actual value is compared with a predetermined set-point value, which is read from the memory inM in particular. If the actual value overshoots the set-point value, a signal I is output by means of the monitoring circuit SC and transmitted from the control unit ECU to a different component of the vehicle electronics.

[0062] In this case, the determination of the sulfur exposure is not to be understood as limiting. Different characteristic values and sensor components S1 corresponding thereto may also be usedparticularly as described above in the general partwhich then monitor a mechanical or thermal loading of the control unit ECU, for example.

[0063] FIG. 2 shows a very simplified circuit diagram of a control unit ECU according to a second exemplary embodiment. The control unit ECU according to the second exemplary embodiment essentially corresponds to that of the first exemplary embodiment. For the sake of simplicity, the control circuit CC and the constituents thereof are omitted in the circuit diagram.

[0064] In contrast to the first exemplary embodiment, the monitoring circuit SC of the control unit ECU of the second exemplary embodiment contains a plurality of sensor components S1, S2, S3. By means of the microcontroller C1, measured values M1, M2, M3 of the sensor components S1, S2, S3 are recorded by the monitoring circuit SC and referred to for determining the actual value of a characteristic value or alternatively for determining actual values of a plurality of characteristic values.

[0065] The actual values or values corresponding thereto are saved in an internal memory inM of the control unit ECU and read and taken into account when determining the actual values of subsequent measurements. The internal memory inM may be integrated in the microcontroller C1 or may be constructed as an additional component.

[0066] The signal I emitted as a function of the comparison result of the actual value or the actual values with a set-point value or corresponding set-point values of the characteristic value(s) is forwarded by means of a signal line from the control unit of the ECU to a different component of the vehicle electronics and a value corresponding to the signal is saved in a fault memory exM. For example, the monitoring circuit SC may be constructed for emitting various signals I as a function of the actual values of the various sensor components S1, S2, S3, which signals correspond to variously strong thermal, mechanical and/or chemical loading of the control unit ECU.

[0067] FIG. 3 shows a very schematized circuit diagram of a control unit ECU according to a third exemplary embodiment. The control unit ECU of the third exemplary embodiment essentially corresponds to that of the second exemplary embodiment.

[0068] In contrast thereto, the signal Ior a value corresponding theretois not only saved in a memory exM however, but rather may additionally be signaled acoustically and/or optically by means of an indicating element Ind. The indicating element Ind is, for example, a constituent of an indicator panelfor example what is known as an instrument clusterwhich is constructed to inform the driver of the motor vehicle about the state of the vehicle. An embodiment of the method for monitoring the control unit ECU, in which the signal I is indicated by means of such an indicating element Ind may also be used and is advantageous for other control units ECU, particularly as are described in connection with the FIGS. 1 and 2.

[0069] In addition, the control unit ECU according to the third exemplary embodiment is differentiated from that of the second exemplary embodiment in that no sensors which are specified for recording environmental influencessuch as, for example, temperature sensors, vibration sensors, moisture sensors and the likeare used as sensor components S1, S2, S3; rather electric or electronic standard components such as resistors, coils, capacitors or diodes are used. The measurement of a characteristic value representative for the thermal, mechanical or chemical loading of the control unit ECU takes place in the present exemplary embodiment in particular by means of the measurement of a deviation of a characteristic value which is design-typical for the respective sensor component S1, S2, S3particularly for a resistor, the ohmic resistance thereof; for a coil, the resistance and/or the inductance thereof; and for a capacitor, the capacitance thereof. In this manner, the measured characteristic value is representative in particular for the thermal, mechanical and/or chemical loading of the respective sensor component S1, S2, S3.

[0070] The sensor components S1, S2, S3 are in particular identical in design to standard components, such as resistors, coils, capacitors or diodes, which are used as electric or electronic components EC in the control circuit CC (omitted in turn in FIG. 3) of the control unit ECU. However, the sensor components S1, S2, S3 are designed in such a manner that they are more sensitive for a thermal, mechanical and/or chemical load than the corresponding components EC of the control circuit CC.

[0071] For example, in the monitoring circuit SC, a ceramic resistor is used as first sensor component S1, the mass and volume of which are larger than those of the largest ceramic resistor in the control circuit CC. For example, a ceramic resistor with the size 2510 according to the EIA standard may be used as sensor component S1 if only ceramic resistors with a size of 1206 or less according to the EIA standard are used in the control circuit CC. Due to the larger mass and dimensions thereof, the sensor component S1 is then more sensitive with respect to mechanical and/or thermal loading than the corresponding component EC of the control circuit CC. For example, the soldering-point aging of the sensor component S1 is accelerated compared to the corresponding component EC.

[0072] A resistor array with silver coating and fine metal structures, which in this manner is sensitive with respect to sulfur exposure, may for example be used as second sensor component S2. Only single resistors, in which less silver is exposed to the sulfur, are for example used as corresponding component EC of the control circuit CC.

[0073] A coil, which is designed to be weaker mechanically than the coils used in the control circuit CC as corresponding components EC, is for example used as third sensor component S3. The sensor component S3 is therefore, for example, more sensitive with respect to vibration fatigue.

[0074] In the present exemplary embodiment, the three sensor components S1, 2, S3 are electrically connected in series and the monitoring circuit SC compares the volume resistance of this series connection with a set-point resistance for recording the measured value. If the actual value of the volume resistance deviates too far from the predetermined set-point value, the monitoring circuit SC signals the end of the technological lifespan of the control unit ECU.

[0075] FIG. 4 shows a very schematized circuit diagram of a control unit ECU according to a fourth exemplary embodiment. The control unit ECU of the fourth exemplary embodiment fundamentally corresponds to that of the first exemplary embodiment.

[0076] However, a multiplicity of similar and, in the present case also structurally identical components EC of the control circuit CC are used as sensor components S1. The sensor component S1 and the similar components EC respectively are therefore both a constituent of the control circuit CC and of the monitoring circuit SC. The control and monitoring circuits CC, SC may be identical in a development. In addition, in the present exemplary embodiment, the microcontrollers C1, C2 of the control and monitoring circuits CC, SC are not spatially separated components.

[0077] In the present exemplary embodiment, the similar components EC are structurally identical resistors. The number of resistors is chosen in such a manner that the failure of a single resistor does not impair the functionality of the control circuit CC for controlling the operating function of the motor vehicle.

[0078] The control unit ECU is, however, constructed by means of the monitoring circuit SC for determining the failure of individual sensor components S1i.e., individual components of the similar components EC. For example, the resistance of the parallel connection of the resistors is determined as actual value. This may take place, e.g., with the aid of a shunt resistor SH for measuring the current flow.

[0079] The resistance is compared with the set-point value, which expediently corresponds to the resistance of the parallel connection when all components EC are operative. A warning signal may be emitted as a function of the comparison result, as described above for example in connection with the third exemplary embodiment. In this case, in a development, various warning stagescorresponding, e.g., to the first, second and third signals described in the general partmay correspond to different numbers of failed resistors.

[0080] The invention is not limited to the exemplary embodiments by the description based on the exemplary embodiments. Rather, the invention includes each novel feature and each combination of features, which includes each combination of features in the exemplary embodiments and patent claims in particular.