Method for actuating a park lock of a vehicle, computer program and computer program product for carrying out the method, and vehicle

Abstract

The invention relates to a method for actuating a park lock of a vehicle. In said method, the park lock is actuated when a determined vehicle speed falls below a definable reference speed of the vehicle, the vehicle speed being determined by means of a rotor position sensor (RPS), which is integrated into the park lock and which provides periodic voltage signals for the determination of the vehicle speed within a control unit of the vehicle. The invention also relates to a computer program, to a computer program product and to a vehicle.

Description

[0001] Description

[0002] Method for activating a parking lock of a vehicle, computer program and computer program product for carrying out the method and vehicle

[0003] The invention relates to a method for actuating a parking lock of a vehicle, a computer program and a computer program product for carrying out this method, and a vehicle with such a computer program or computer program product.

[0004] Parking locks are known in which an electrically actuated lever with a ratchet tooth interacts with a gear of a drive train to block or lock the drive train. For example, see DE 102017 102 804 A1, which describes such a parking lock with a ratchet mechanism.

[0005] Such parking locks can be actuated below a definable, critical vehicle speed limit, which is monitored by sensors based on a determined vehicle speed. Wheel speed information is used to determine the vehicle speed and provided to a vehicle control unit.

[0006] The object of the present invention is to improve the safety of such parking locks or parking lock systems.

[0007] This object is achieved by a method proposed and protected according to claim 1.

[0008] A method for actuating a parking lock of a vehicle is proposed. The parking lock is actuated when a defined reference speed of the vehicle is undershot by a determined vehicle speed. The vehicle speed is determined using a rotor position sensor integrated into the parking lock, which provides periodic voltage signals for determining the vehicle speed within a control unit of the vehicle.

[0009] The proposed method is based on the concept of integrating a rotor position sensor into a parking lock. Reference is made here to the German patent application with the application number 10 2022 207 258.8, which discloses such a concept as an example. A position sensor arrangement comprising an inductive signal transmitter and a sensor component that interacts with the signal transmitter and is at least partially made of metal is accommodated in a housing of the parking lock. This position sensor arrangement detects an absolute angular position or angular orientation of a rotor of an electric motor of an electric motor drive unit for driving a vehicle, said rotor being connected to a shaft.

[0010] Within the scope of the present invention, it is proposed to use such a rotor position sensor not only for efficient electronic commutation of a separately excited or permanently excited synchronous machine of the electric motor drive unit, but also for determining a highly accurate vehicle speed.

[0011] In a further embodiment, it is proposed that the highly accurate vehicle speed thus determined is used to verify the plausibility of vehicle speed control information determined based on other sensor signals, which as such represents primary vehicle speed information for orientation. This vehicle speed control information can be determined, for example, from wheel speed sensor signals within a vehicle control unit, such as an ESP (Electronic Stability Program) control unit - also called ESC (Electronic Stability Control) control unit. This is an electronic driver assistance system designed to counteract a vehicle skidding by braking individual wheels. This is also referred to as a so-called vehicle dynamics control system. This redundancy supports the release of a drivetrain lock by the parking lock or safeguards it (veto option).

[0012] For example, a control unit of an inverter can be provided in the form of a central control unit, in which, among other things, signal processing for the parking lock can also take place. A first vehicle speed information item is checked for plausibility with a second vehicle speed information item, i.e., the vehicle speed information determined by the rotor position sensor integrated into the parking lock, in order to be able to issue approval for a locking request. This makes it possible to compensate for inaccuracies in vehicle speed information determined, for example, based on wheel speed sensor signals. This can prevent unintentional activation of the parking lock above the aforementioned reference vehicle speed.

[0013] In a further embodiment, it is proposed that the thus determined - highly accurate - vehicle speed itself is used as vehicle speed guidance information, against which plausibility can then be checked as such if necessary.

[0014] In a further embodiment, it is proposed that the thus determined - highly accurate - vehicle speed is determined within a control unit integrated into the parking lock.

[0015] Furthermore, a computer program for carrying out the method described above is proposed, as well as a computer program product comprising program code means stored on a computer-readable data carrier for carrying out the method described above when the program code means are executed on a computer.

[0016] Furthermore, a vehicle with a computer program or a computer program product of the type described above is proposed. A vehicle is understood to mean any type of vehicle or motor vehicle that is powered by an electric motor, but in particular passenger cars and / or commercial vehicles in the form of electric or hybrid vehicles. These can be semi-autonomous or fully autonomous vehicles.

[0017] Furthermore, a use of a rotor position sensor integrated into a parking lock of an electric motor drive unit for driving a vehicle is proposed for actuating the parking lock, wherein a vehicle speed is determined within a control unit of the vehicle on the basis of periodic voltage signals provided by the rotor position sensor in order to release a locking request.

[0018] The invention will be explained in detail below with reference to the figures. Further advantageous developments of the invention will become apparent from the dependent claims and the following description of preferred embodiments. A single figure schematically shows:

[0019] Fig. 1 an electric or hybrid vehicle with a lockable electric motor drive unit.

[0020] The vehicle 2 illustrated in Fig. 1 comprises an electric motor drive unit 4 with a permanent magnet or separately excited synchronous machine as the electric motor for driving the vehicle, wherein the electric motor can optionally be combined with a reduction gear, a high-voltage battery 8, and an inverter 6, which is included in the power electronics of the vehicle 2 and which establishes the connection between the electric motor of the electric motor drive unit 4 and the high-voltage battery 8. The power electronics can optionally comprise an integrated voltage converter 10, which supplies a low-voltage electrical system of the vehicle from the high-voltage electrical system of the vehicle. A control unit of the inverter 6 controls, regulates, and monitors the electric motor and ensures a demand-oriented torque supply and speed control of a drive train of the vehicle 2.In addition, the inverter 6 converts the direct voltage of the high-voltage battery 8 into the alternating voltage required by the electric motor.

[0021] The power electronics, or the inverter 6 included within the power electronics, supplies not only the electric motor with power, but also the high-voltage battery 8—namely when the electric motor operates as a generator and feeds power into the high-voltage battery 8. During this process, known as recuperation, it converts the alternating current generated by the electric motor into direct current, thereby charging the high-voltage battery 8.

[0022] A parking lock – also called a locking device – is integrated into the electric motor drive unit 4, which in turn incorporates a rotor position sensor (RPS). This rotor position sensor (RPS) serves, on the one hand, to efficiently commutation the electric motor and, on the other hand, to provide periodic, sine-cosine-shaped voltage signals, which are then sent to a control unit of the vehicle, such as the control unit of the inverter 6. From these voltage signals, the control unit calculates an absolute angle of a rotor of the electric motor or an exact angular position of the rotor or a rotor shaft, as well as its exact rotational speed. By utilizing a fixed or, if necessary, switchable gear ratio between the rotor shaft of the electric motor and one of the drive wheels, the control unit can determine the vehicle speed with high precision.

[0023] The vehicle speed determined in this way can be consulted or used to verify the plausibility of vehicle speed control information determined based on other sensor signals. For example, the vehicle speed determined in this way can be used in the control unit of inverter 6 to verify the plausibility of this vehicle speed control information and thus to enable a rotor shaft lock. After such a plausibility check and release, the control unit of inverter 6 issues a locking command to the parking lock. Such redundant determination of the vehicle speed increases the functional security of the parking lock. Thus, for example, the control unit of inverter 6 can function as a central control unit for the parking lock.

[0024] Alternatively, the vehicle speed determined in this way can itself be used as vehicle speed guidance information, against which plausibility can be checked if necessary.

[0025] The parking lock itself comprises a control unit in which the said determination of the vehicle speed can be carried out based on the said sine-cosine-shaped voltage signals.

[0026] In this context, reference is made to the German patent application with the application number 10 2022 207 258.8 - already mentioned at the beginning - in which such a concept is disclosed by way of example, according to which a parking lock or locking device is integrated into the electric motor drive unit 4 and is accommodated by a housing of the electric motor, wherein in turn a rotor position sensor RPS is integrated into the parking lock.

[0027] In this case, reference is made to the printed circuit board (PCB) described in this application as part of the control unit of the parking lock. This printed circuit board has control electronics with an integrated signal transmitter with a coil arrangement, which interacts with a sensor component in the form of a metallic, disc-like element that is stationary relative to the rotor shaft of the electric motor. This metallic element functions like a sensor wheel, which, in conjunction with the signal transmitter, generates the aforementioned sine-cosine voltage signals. The printed circuit board can have a computing or processing unit, which determines the aforementioned vehicle speed from the sine-cosine voltage signals. In the proposed method for actuating the parking lock of the vehicle, the parking lock is used to lock or release the parking lock.Locking of the drive train is actuated when a definable reference speed of the vehicle is undercut by a vehicle speed determined based on the said sine-cosine-shaped voltage signals.

[0028] The control units described above comprise a digital microprocessor unit (CPU) data-connected to a memory system and a bus system, a random access memory (RAM), and a storage device. The CPU is configured to process commands embodied as a program stored in a memory system, to detect input signals from the data bus, and to output output signals to the data bus. The memory system can have various storage media in the form of magnetic, solid-state, and other non-volatile media, on which a corresponding computer program for implementing the method and the advantageous embodiments is stored. The program can be designed in such a way that it embodies or is capable of executing the method aspects described here, so that the CPU can execute the steps of such methods and thus control both the vehicle and the parking lock or locking device.

[0029] Suitable for carrying out the method is a computer program which has program code means for carrying out all the steps of any of the claims or method claims when the program is executed in the CPU.

[0030] The computer program can be easily read into existing control electronics and used to control both the vehicle and the parking lock or locking device.

[0031] For this purpose, a computer program product is provided with program code means stored on a computer-readable data carrier for carrying out the method according to any of the claims when the computer program product is executed in the CPU. The computer program product can also be integrated into the control electronics as a retrofit option.

[0032] Although exemplary embodiments are explained in the foregoing description, it should be noted that numerous modifications are possible. Furthermore, it should be noted that the exemplary embodiments are merely examples and are not intended to limit the scope of protection, applications, or structure in any way. Rather, the foregoing description provides the skilled person with a guide for implementing at least one exemplary embodiment, whereby various modifications, particularly with regard to the function and arrangement of the described components, can be made without departing from the scope of protection as it results from the claims and equivalent combinations of features.

Claims

Patent claims 1 . A method for actuating a parking lock of a vehicle, wherein the parking lock is actuated when a determined vehicle speed falls below a definable reference speed of the vehicle, characterized in that the vehicle speed is determined by means of a rotor position sensor (RPS) integrated into the parking lock, which provides periodic voltage signals for determining the vehicle speed within a control unit of the vehicle.

2. Method according to claim 1, wherein the vehicle speed thus determined is used to check the plausibility of vehicle speed control information determined based on other sensor signals.

3. Method according to claim 1, wherein the vehicle speed thus determined is used as vehicle speed control information.

4. Method according to one of the preceding claims, wherein the vehicle speed thus determined is determined within a control unit integrated into the parking lock.

5. Computer program for carrying out a method according to one of the preceding claims 1 to 4.

6. A computer program product comprising program code means stored on a computer-readable data carrier for carrying out the method according to any one of the preceding claims 1 to 4 when the program code means are executed on a computer.

7. Vehicle with a computer program according to claim 5 or a computer program product according to claim 6.

8. Use of a rotor position sensor (RPS) integrated into a parking lock of an electric motor drive unit for driving a vehicle for actuating the parking lock, wherein a vehicle speed is determined within a control unit of the vehicle on the basis of periodic voltage signals provided by the rotor position sensor (RPS) in order to release a locking request.

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