Method for determining the functionality of a drive unit in a drive system of a motor vehicle, control unit and computer program product

Abstract

Method for determining the functionality of at least one drive unit (20, 30, 40) in a drive system (100), in particular in a drive system (100) of a motor vehicle, comprising the steps: - Detecting at least one physical property of the at least one drive unit (20, 30, 40) while the at least one drive unit (20, 30, 40) is in a passive switching state, and - Determining the functionality of the at least one drive unit (20, 30, 40) for an active switching state of the at least one drive unit (20, 30, 40) based on the recorded at least one physical property in the passive switching state, characterized in that a switching operation is carried out in the drive system (100) by means of the at least one drive unit (20, 30, 40) and at least one physical property is recorded during the switching operation, wherein a comparison is then carried out between the at least one physical property during the switching operation and the at least one physical property in the passive switching state and, based on this comparison, an evaluation for determining the functionality is carried out, in particular using a statistical model, wherein a switching operation is carried out in the drive system (100) depending on the evaluation for determining the functionality.

Description

[0001] The present invention relates to a method for determining the functionality of a drive unit in a drive system of a motor vehicle. The invention further relates to a control unit configured and designed for determining the functionality of a drive unit in a drive system of a motor vehicle. The invention also relates to a computer program designed for use in a control unit and configured and designed for determining the functionality of a drive unit in a drive system of a motor vehicle.

[0002] The increasing use of various drive units in motor vehicles necessitates high-quality diagnostics. When implementing novel, complex transmission concepts, faults can occur in these components that are difficult to diagnose adequately.

[0003] In known solutions, drive units or actuators (in a broader sense) read back their own movement, usually increments of a rotary motion, after a change request is made by the higher-level control system. An absolute position is determined based on this data. Errors are detected if the rotary motion cannot be performed as requested, if a rotary motion is detected without a request, or if currents and voltages in the actuator control circuitry do not correspond to a setpoint. Depending on the type of safety requirements, optionally redundant sensors are used within the framework of incremental or displacement sensing.

[0004] EP 2 331 848 B1 analyzes a transmission using inertia data, specifically in relation to the currently engaged gear. This means that active components of the transmission are diagnosed. Consequently, faults can only be diagnosed once they have already occurred or led to malfunctions. Therefore, drive units and actuators must be designed to be particularly robust in order to prevent faults from occurring in the first place. However, this results in correspondingly high costs.

[0005] Methods for determining the functionality of a drive unit are known from DE 42 20 286 A1 and GB 2 112 089 A.

[0006] The object of the present invention is to at least partially overcome the disadvantages described above. In particular, it is an object of the present invention to provide an improved method for determining the functionality of a drive unit for a switching operation in a drive system, a control unit, and a computer program product for this purpose, wherein the functionality can be determined in a simple and cost-effective manner, and faulty operating processes in the drive system can be prevented.

[0007] The aforementioned problem is solved by the patent claims. In particular, the problem is solved by the method according to claim 1, the control unit according to claim 8, and the computer program product according to claim 9. Further advantages of the invention will become apparent from the dependent claims, the description, and the drawings. Features described in connection with the method naturally also apply in connection with the control unit and the computer program product according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always includes, or allows for, reciprocal reference.

[0008] According to a first aspect of the present invention, a method for determining the functionality of at least one drive unit in a drive system, in particular in a drive system of a motor vehicle, is provided. The method comprises the following steps: - Detecting at least one physical property of the at least one drive unit while the at least one drive unit is in a passive switching state, and - Determining the functionality of the at least one drive unit for an active switching state of the at least one drive unit based on the recorded at least one physical property in the passive switching state.

[0009] In the passive switching state, the at least one drive unit and switching elements controlled or moved by the at least one drive unit can be tested for functionality without the at least one drive unit or the switching elements influencing an operating process, such as a switching operation, in the drive system or a transmission of the drive system. However, adjusting the at least one drive unit and recording the at least one physical property during this process can be carried out during operation of the drive system, in which at least parts of the drive system are active. The recording of the at least one physical property is made available prior to a request for an operating process in which the at least one drive unit is to be activated.This allows faults in at least one drive unit to be diagnosed before a faulty operating process, such as a switching operation, would be carried out.

[0010] At least one physical property is also recorded, in particular, when at least one drive unit is in the passive switching state and at least one other drive unit of the drive system is in an active switching state.

[0011] The drive system is designed to propel at least one object. When the at least one drive unit is in the passive switching state, it cannot contribute to propelling the at least one object. The at least one drive unit can be configured as an electric motor, internal combustion engine, or transmission unit within the drive system. In the passive switching state, the electric motor, internal combustion engine, or transmission unit is decoupled from a driven unit for transmitting a drive or driven force to the at least one object, which in this case can be the chassis or wheels of a motor vehicle. That is, in the passive switching state, the electric motor or internal combustion engine cannot be used to propel the motor vehicle, as it is essentially idling.In the active switching state, the at least one drive unit can contribute to driving the at least one object, for example the wheels of the motor vehicle, via the output unit.

[0012] Based on the recorded at least one physical property of the at least one drive unit in the passive switching state of the drive unit, it can be concluded whether the at least one drive unit would also function flawlessly in the active or activated switching state.

[0013] After recording the at least one physical property, a comparison is preferably made between the recorded at least one physical property and at least one corresponding target physical property. Based on this comparison, the functionality of the at least one drive unit for the active switching state or a corresponding switching operation is determined. If, for example, the comparison reveals that the at least one physical property does not correspond to the corresponding target physical property because the at least one drive unit cannot be moved or operated as desired, it can be assumed that the at least one drive unit is also not suitable for performing a switching operation in the active switching state, or cannot be switched into the active switching state without errors, or if this is imminent.In this case, an impending fault can be rectified through maintenance or repair before it actually occurs. If, however, a comparison reveals that the at least one physical property corresponds to the associated at least one target physical property, it can be assumed that the at least one drive unit is also suitable for performing a switching operation or can be switched into the active switching state or operated in it without errors. The target physical property is preferably not to be understood as a single value, but as a range of values, a characteristic curve, or a combination of several properties. The at least one drive unit can be adjusted by an adjustment unit. The at least one physical property can be detected by a detection unit, for example, a suitable sensor.The functionality of at least one drive unit for the active switching state or a drive state for driving at least one object can be detected by a detection unit, for example a computing unit of a control unit.

[0014] Within the scope of the present invention, a switch between the passive switching state and the active switching state of the at least one drive unit can be performed depending on the determined functionality of the at least one drive unit. This prevents a faulty operating process, such as a switching operation, from being initiated or carried out. If it is recognized based on the determined functionality that a particular operating process is likely not to be executed correctly, another operating process, such as an alternative switching strategy, can be selected. Damage to the drive system, which is particularly designed as a gearbox drive system, can thus be prevented. Accordingly, the costs for repairing the damage can be avoided. The drive unit is preferably designed as a drive unit for driving gearbox components in a gearbox drive system.

[0015] Adjusting the at least one drive unit can refer to changing its position or its state. The change in state can be a change in speed and / or torque.

[0016] According to a further development of the present invention, it is possible for the at least one drive unit (hereinafter referred to as the drive unit in certain sections) to be continuously adjusted in the passive switching state and for the at least one physical property (hereinafter referred to as the physical property in certain sections) to be continuously detected. The continuous adjustment of the drive unit and the corresponding continuous detection of the physical property during the adjustment are only facilitated by the detection of the physical property in the passive switching state of the drive unit according to the invention. Through the continuous adjustment of the drive unit and the corresponding continuous detection of the physical property in the passive switching state of the drive unit, accurate statements about the functionality or...A malfunction of the drive unit in its passive switching state can be detected. This allows for the reliable and timely prediction of potentially faulty operation of the drive system. Consequently, any faulty operation, such as a switching operation in the drive system, can be reliably prevented in a timely manner, thus avoiding damage to the drive system. Continuous adjustment or continuous detection, as used here, refers to a defined, repetitive, and possibly regularly recurring adjustment or detection process.

[0017] Furthermore, it is provided that in a method according to the invention, a switching operation is carried out in the drive system by means of the drive unit, and a physical property is recorded during the switching operation. Subsequently, a comparison is made between the physical property during the switching operation and the physical property, which can be understood as the target physical property, in the passive switching state. Based on this comparison, an evaluation is carried out to determine the functionality, in particular using a statistical model. The recorded physical property during the switching operation, or the change behavior of the physical property during the switching operation, can be understood as the actual physical property. By comparing the target physical property and the actual physical property, the accuracy can be determined.The reliability of determining the functionality of the drive unit can be assessed. This allows for a classification of when, or with which assessment results, a conclusion can be drawn from a functioning adjustment in the passive switching state to a functioning adjustment in the active switching state, i.e., an adjustment during the switching process. Furthermore, it is possible to initially compile statistics during the operating life of the drive system, recording which assessment results, based on adjustment in the passive switching state, also allowed for a complete adjustment during the switching process, and when they did not. This is suitable for types of errors that can only be partially addressed during the development of the drive system. Based on this data, the drive unit or multiple drive units can be diagnosed using estimation functions or other methods.This can be achieved by programming a control unit in a vehicle with the drive system, particularly in the form of a vehicle transmission, or by evaluating vehicle data offline after reading it out in a workshop or online transmission and re-parameterization. It is also possible to transfer the statistical results to other vehicles or motor vehicles to improve control or fault analysis.The evaluation can consider whether and how often a prediction regarding the functionality of the drive unit for the switching process was correct, how often a prediction regarding the functionality of the drive unit for the switching process was incorrect, and how often a prediction was not feasible due to errors in recording the physical property during adjustment of the drive unit in the passive switching state or even during adjustment of the drive unit in the passive switching state itself. Based on the comparison and / or evaluation, tolerances and aging effects in the drive system with respect to the drive unit can be identified and compensated for. This has a positive effect on the longevity of the drive system. Adjustment of the drive unit in the passive switching state can be carried out or modified based on the data obtained.

[0018] Furthermore, it is provided that in a method according to the present invention, a switching operation or other operation in the drive system is carried out depending on the evaluation for determining functionality. This ensures that the switching operation is only carried out based on the detected physical property during adjustment of the drive unit in the passive switching state if the detected physical property also allows for a reliable conclusion to be drawn about the behavior of the drive unit during the switching operation. If, for example, the comparison, which is preferably carried out continuously, shows that the target physical property always matches the actual physical property, it can be assumed that determining the functionality of the drive unit based on the target physical property works reliably.In this case, the functionality determined according to the invention, or the correspondingly predicted functionality of the drive unit, can be used or taken into account with a certain degree of confidence to carry out a desired switching operation. However, if the comparison reveals that the target physical property rarely matches the actual physical property, or that the actual physical property frequently deviates significantly from the target physical property, it can be assumed that determining the functionality of the drive unit for the switching operation based on the target physical property while adjusting the drive unit in the passive switching state is not reliable. In this case, the detection of the physical property should be modified or corrected. Furthermore, in this case, the determined functionality should be...The predicted functionality of the drive unit should not, at least for the time being, be used as a basis for deciding whether to carry out a desired switching operation or operation.

[0019] Furthermore, the method according to the invention can not only distinguish between a functioning and a defective drive unit, but also detect premature aging of the drive unit. This aging detection can trigger a request for maintenance or repair, or the switching behavior can be influenced by means of an alternative circuit to inhibit further aging.

[0020] Within the scope of the present invention, it is further possible that, in a method, the at least one drive unit in the drive system is adjusted in the passive switching state according to a defined test pattern. Using a defined test pattern for adjusting the drive unit in the passive switching state, the physical properties can be recorded particularly comprehensively and precisely, and thus the functionality of the drive unit for the switching process or other operation can be determined with corresponding accuracy. The defined test pattern preferably refers to a specific procedure for adjusting the drive unit in the passive switching state. For example, within the test pattern, the drive unit is adjusted alternately quickly and slowly and / or first within a first defined range and then within a second defined range.The term "test pattern" refers to at least one test pattern. This means that, within the scope of the present invention, multiple and / or different test patterns or adjustments can be performed within the test patterns.

[0021] According to the invention, it can be advantageous if, in a method, the defined test pattern is created based on comparison and / or evaluation. That is, the test pattern, or at least one test pattern, can be adaptively adjusted to capture the physical property during adjustment of the drive unit and / or to determine the functionality of the drive unit for the active switching state. Thus, a first test pattern can be performed, and depending on the determined functionality of the drive unit, a second test pattern can then be performed, the second of which differs from the first. This allows the physical property to be captured with particular flexibility and the functionality of the drive unit for the active switching state to be determined with corresponding accuracy.

[0022] A further advantage can be found in a method according to the invention if the functionality of the at least one drive unit for a drive process in a drive system in a motor vehicle is tested, wherein the detection of the at least one physical property in the passive switching state and the determination of the functionality of the at least one drive unit based on the detected at least one physical property are carried out by a control unit in the motor vehicle during a journey. This allows a faulty switching process or operation of the drive system to be prevented in a timely manner during a journey. This leads to a correspondingly high level of driving safety during a journey and to safe operation of the vehicle throughout its entire service life.Because adjusting the drive unit in the passive switching state does not affect the operation of the drive system, the functionality of the drive unit for the active switching state of the drive unit can be continuously maintained while the vehicle is driving.

[0023] Furthermore, in a method according to the present invention, the at least one physical property of the at least one drive unit detected during adjustment, as well as the determined functionality of the at least one drive unit, can be stored in the form of corresponding data. By storing the data regarding the detected physical property during adjustment and the determined functionality of the drive unit, it is possible to perform the functionality determination at a later time than when this data is obtained. Thus, the stored data can, for example, also be read out and evaluated in a workshop during customer service.In the workshop, if errors are detected during the recording of the physical properties while adjusting the drive unit in the passive switching state and / or during the determination of the drive unit's functionality in the active switching state, appropriate countermeasures can be taken to rectify the errors based on the data. Furthermore, the stored data can be used as the basis for a statistical analysis to evaluate the accuracy of determining the drive unit's functionality in the active switching state. Based on a sufficiently comprehensive statistical analysis of the data, the determination of functionality can be reliably assessed.This prevents relying on an alleged functionality of the drive unit for the active switching state, which may not have been correctly determined, when performing the switching process or any other operation of the drive system.

[0024] In a method according to the invention, the at least one physical property can be a moment of inertia, a torque, an acceleration, an elasticity, a rotational speed, a velocity, and / or a temperature of the at least one drive unit or within the at least one drive unit. Mathematical operations such as differentiation and / or integration can be used to obtain these properties.

[0025] According to a further aspect of the present invention, a control unit is provided which is configured and designed to carry out a method as described in detail above. The control unit according to the invention thus offers the same advantages as described in detail with reference to the method according to the invention. The control unit or a corresponding control system has an adjustment unit for adjusting the drive unit in the passive switching state. For this purpose, the drive unit can be controlled by the control unit accordingly, in particular electrically. The control unit or a control system further comprises at least one detection unit for detecting at least one physical property of at least one drive unit during the adjustment of the drive unit.The detection unit preferably comprises at least one sensor for acquiring measured variables to determine at least one physical property of the drive unit. Furthermore, the control unit comprises a determination unit for ascertaining the physical property(ies) and thus the functionality of the drive unit in the active switching state based on the measured variables during adjustment of the drive unit in the passive switching state. The determination unit preferably comprises a processing unit for determining the functionality. In addition, the control unit comprises a comparison unit for comparing the at least one physical property during the active switching state with the at least one physical property during the passive switching state.The comparison unit is preferably configured for comparing the determined physical property with a reference behavior of the physical property. The comparison unit can be implemented within the processing unit. An evaluation unit for assessing the functionality can also be implemented in the processing unit. A control system according to the invention further comprises a memory and a storage unit, such that the at least one physical property detected during the passive switching state, as well as the determined functionality of the drive unit, can be stored in the memory in the form of corresponding data.

[0026] According to a further aspect of the present invention, a computer program product is provided that is designed for use in a control unit as described above and is configured and designed to carry out a method as described above. Thus, the computer program product according to the invention also offers the same advantages as described in detail above. The computer program product can be written as computer-readable instruction code in any suitable programming language, such as Java, C, C+, or C++, and is implemented as executable instruction code in the control unit. The computer program product can be stored on a computer-readable storage medium (data disk, removable drive, volatile or non-volatile memory, built-in memory / processor, etc.).Furthermore, the computer program product can be made available on a network, such as the internet, from which it can be downloaded by a user as needed. The computer program product can be implemented using a computer program (i.e., software), one or more specialized electronic circuits (i.e., hardware), or in any hybrid form (i.e., using both software and hardware components).

[0027] Further improvements to the invention will become apparent from the following description of various embodiments of the invention, which are schematically illustrated in the figures. All features and / or advantages arising from the claims, the description, or the drawings, including design details and spatial arrangements, can be essential to the invention, both individually and in various combinations.

[0028] They each show schematically: Fig. 1 a drive system comprising a control unit according to the invention and a computer program product according to the invention in a first operating state, Fig. 2 the in Fig. 1 Drive system shown in a second operating state, Fig. 3 that in Fig. 1 drive system shown in a third operating state, and Fig. 4 that in Fig. 1. Drive system shown in a fourth operating state.

[0029] Elements with the same function and mode of operation are in the Fig. 1, Fig. 2, Fig. 3 to Fig. 4 each with the same reference numerals.

[0030] Fig. Figure 1 shows a drive system 100 with a control unit 60, which is configured to carry out a method according to the invention. A computer program 70, which is also configured and designed to carry out a method according to the invention, is stored in the control unit 60.

[0031] The drive system 100 comprises a transmission 10. The transmission has a first clutch 11, a second clutch 12, a third clutch 13, and a fourth clutch 14. The transmission 10 also has a gear unit 15 in the form of a gear stage.

[0032] The gearbox 10 can be connected to a first electric motor 20 (drive unit), a second electric motor 30 (drive unit), and an internal combustion engine 40 (drive unit). More precisely, the first electric motor 20 can be coupled to the gearbox unit 15 via the first clutch 11. The second electric motor 30 can be coupled to the gearbox unit 15 via the third clutch 13. The internal combustion engine 40 can be coupled to the gearbox unit 15 via the second clutch 12.

[0033] The drive system 100 further comprises an output unit 50, through which a mechanical movement can be transmitted to a chassis or wheels of the motor vehicle in which the drive system 100 is arranged. The output unit 50 can be coupled to the transmission unit 15 by means of the fourth clutch 14. Fig. Figure 1 shows an operating state of the drive system 100 in which all clutches 11, 12, 13, 14 are open. In this case, measurements of the individual rotational speeds of the first electric motor 20, the second electric motor 30, the internal combustion engine 40, and the transmission unit 15 are performed. Furthermore, the moments of inertia of the first electric motor 20, the second electric motor 30, and the internal combustion engine 40 (excluding the transmission unit 15) are determined.

[0034] In Fig. Figure 2 shows an operating state of the drive system 100 in which only the first clutch 11 is engaged. This means that the first electric motor 20 is coupled to the transmission unit 15. In this case, measurements are taken of the individual speeds of the first electric motor 20, the second electric motor 30, the internal combustion engine 40, and the transmission unit 15. Additionally, the moment of inertia of the first electric motor 20 with the transmission unit 15 is measured.

[0035] In Fig. Figure 3 shows an operating state of the drive system 100 in which only the second clutch 12 is engaged. This means that the internal combustion engine 40 is coupled to the transmission unit 15. In this case, measurements are taken of the individual rotational speeds of the first electric motor 20, the second electric motor 30, the internal combustion engine 40, and the transmission unit 15. Additionally, the moment of inertia of the internal combustion engine 40 with the transmission unit 15 is measured.

[0036] In Fig. Figure 4 shows an operating state of the drive system 100 in which the first clutch 11 and the third clutch 13 are engaged. This means that the first electric motor 20 and the second electric motor 30 are coupled to the gearbox 15. In this case, a speed plausibility check is performed for the first electric motor 20, the second electric motor 30, and the gearbox 15. Furthermore, a motor-driven test of the first electric motor 20 and a generator-driven test of the second electric motor 43 are carried out. Additionally, the moment of inertia of the first electric motor 20, the second electric motor 30, and the gearbox 15 can be determined, taking into account the torques provided by the first electric motor 20 and the second electric motor 30.

[0037] With reference to Fig.2 A method according to the invention for determining the functionality of the combustion engine 40 and the second electric motor 30 in the drive system 100 is then described.

[0038] First, the combustion engine 40 and the second electric motor 30 are adjusted in their passive switching state. More precisely, both motors 30 and 40 are started up or operated accordingly as part of a test setup. During this operation of the two motors 30 and 40, their rotational speed and moment of inertia are recorded. Subsequently, the functionality of the two motors 30 and 40 in an active switching state, i.e., a switching state in which the first and third clutches 11 and 13 are engaged, is determined based on the recorded physical properties during the adjustment or operation of the two motors 30 and 40 in their passive switching state. Reference symbol list 10 gearboxes 11 first clutch 12 second clutch 13 third clutch 14 fourth clutch 15 Gear unit 20 first electric motor 30 second electric motor 40 internal combustion engine 50 output unit 60 Control unit 70 Computer program product 100 transmission system

Claims

[1] Method for determining the functionality of at least one drive unit (20, 30, 40) in a drive system (100), in particular in a drive system (100) of a motor vehicle, comprising the steps: - Detecting at least one physical property of the at least one drive unit (20, 30, 40) while the at least one drive unit (20, 30, 40) is in a passive switching state, and - Determining the functionality of the at least one drive unit (20, 30, 40) for an active switching state of the at least one drive unit (20, 30, 40) based on the recorded at least one physical property in the passive switching state characterized by, that in the drive system (100) a switching operation is carried out by means of the at least one drive unit (20, 30, 40) and at least one physical property is recorded during the switching operation, wherein a comparison is subsequently carried out between the at least one physical property during the switching operation and the at least one physical property in the passive switching state and based on this comparison an evaluation for determining the functionality is carried out, in particular on the basis of a statistical model, wherein a switching operation in the drive system (100) is carried out depending on the evaluation for determining the functionality. [2] Method according to claim 1, characterized by , that at least one drive unit (20, 30, 40) is continuously adjusted in the passive switching state and at least one physical property is continuously recorded accordingly. [3] Method according to any of the preceding claims, characterized by , that the at least one drive unit (20, 30, 40) in the passive switching state of the at least one drive unit (20, 30, 40) in the drive system (100) is adjusted according to a defined test pattern. [4] Method according to claim 3, characterized by , that the defined test pattern is created based on comparison and / or evaluation. [5] Method according to any of the preceding claims, characterized by, that the functionality of the at least one drive unit (20, 30, 40) for a drive operation in a drive system (100) in a motor vehicle is carried out, wherein the detection of the at least one physical property in the passive switching state and the determination of the functionality of the at least one drive unit (20, 30, 40) on the basis of the detected at least one physical property is carried out by a control unit (60) in the motor vehicle during a journey of the motor vehicle. [6] Method according to any of the preceding claims, characterized by , that the recorded at least one physical property of the at least one drive unit (20, 30, 40) in the passive switching state as well as the determined functionality of the at least one drive unit (20, 30, 40) are stored in the form of corresponding data. [7] Method according to any of the preceding claims, characterized by, that at least one physical property is a moment of inertia, a torque, an acceleration, an elasticity, a rotational speed, a velocity and / or a temperature of the at least one drive unit (20, 30, 40). [8] Control unit (60) configured to carry out a method according to any of the preceding claims. [9] Computer program product (70) designed for use in a control unit (60) and configured and designed to perform a method according to any one of claims 1 to 7.

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