METHOD FOR ENGAGING A PARKING LOCK OF A MOTOR VEHICLE, AND MOTOR VEHICLE

Abstract

A method for engaging a parking lock of a motor vehicle having a service brake and a parking brake, in which the parking lock is engaged, while by means of a braking device of the motor vehicle, the rolling away of the motor vehicle is at least restricted, wherein as the braking device, an additionally provided braking device of the motor vehicle, different from the service brake and from the parking brake, is used.

Claims

1-12 (canceled)

13. A method for engaging a parking lock of a motor vehicle comprising: a service brake and a parking brake, in which the parking lock is engaged, while by means of a braking device of the motor vehicle, the rolling away of the motor vehicle is at least restricted, wherein as the braking device, an additionally provided parking device of the motor vehicle, different from the service brake and from the parking brake is used.

14. The method according to claim 13, wherein the braking device comprises at least one electric motor designed for driving the motor vehicle, by means of which the rolling away of the motor vehicle is at least restricted in such way that, by means of the electric motor, at least one shaft of the motor vehicle is moved several times alternately in a first rotation direction and in a second rotation direction opposite to the first rotation direction.

15. The method according to claim 13, wherein the braking device has a secondary brake system comprising an electronic brake booster that can be actuated by means of a fluid, by means of which the rolling away of the motor vehicle is restricted, in particular prevented in such way that, the electronic brake booster effects a pressure of the fluid for actuating the braking device, independently of the actuation of the electronic brake booster that is effected by a person.

16. The method according to claim 13, wherein by means of at least one sensor device, at least one measurement value characterizing a rolling speed of the motor vehicle is recorded, wherein the parking lock is engaged, depending on the recorded measurement value.

17. The method according to claim 16, wherein the parking lock is engaged when the measurement value falls below a predetermined threshold value.

18. The method according to claim 16, wherein the measurement value comprises a rotational speed of at least one wheel of the motor vehicle and the sensor device comprises at least one wheel speed sensor, by means of which the rotational speed of the wheel is recorded, wherein the parking lock is engaged, depending on the recorded rotational speed of the wheel.

19. The method according to claim 16, wherein the measurement value comprises a rotational speed of a shaft of the motor vehicle, in particular of the engine of the motor vehicle designed for driving the motor vehicle, and the sensor device comprises at least one shaft speed sensor, by means of which the rotational speed of the shaft is recorded, wherein the parking lock is engaged, depending on the recorded rotational speed of the shaft.

20. The method according to claim 13, wherein based on a satellite-based navigation system, a speed of the motor vehicle is determined, wherein the parking lock is engaged, depending on the determined speed.

21. The method according to claim 13, wherein after engaging the parking lock, the braking device is deactivated.

22. The method according to claim 13, wherein the rolling away of the motor vehicle is automatically at least restricted by means of the braking device, by controlling the braking device with an electronic computing device of the motor vehicle.

23. The method according to claim 22, wherein the initially moving motor vehicle is automatically braked via the braking device by means of the electronic computing device of the motor vehicle, by controlling the braking device with the computing device, whereupon by means of the braking device, the rolling away of the motor vehicle is at least restricted.

24. A Motor vehicle comprising: a parking lock, a service brake, and a parking brake, wherein a braking device, different from the service brake and from the parking brake, is additionally provided, which is designed to at least restrict the rolling away of the motor vehicle while the parking lock is engaged.

Description

[0032] Further advantages, features and details of the invention result from the following description of a preferred exemplary embodiment and from the drawing. The features and combination of features mentioned above in the description as well as the features and combination of features mentioned below in the FIGURE description andor shown in the single FIGURE alone can be used not only in the respectively specified combination but also in other combinations or alone, without leaving the scope of the invention.

[0033] The drawing shows, in the single FIGURE, a flow chart for illustrating a method according to the invention for engaging a parking lock of a motor vehicle.

[0034] The single FIGURE shows a flow chart for illustrating a method for engaging a parking lock of the motor vehicle having the parking lock, a service brake and a parking brake, which is designed, for example, as a car, particularly as a passenger car. The motor vehicle further comprises, for example, an electronic computing device, by means of which an electronic stability program for controlling driving dynamics is realized so that critical driving conditions can be counteracted actively and, in particular automatically, by means of the electronic stability program.

[0035] The motor vehicle further comprises, for example, at least one sensor device, by means of which, for example, in the first step S1 of the method, at least one measurement value characterizing the speed, in particular a rolling speed, of the motor vehicle is recorded. The sensor device comprises, for example, per wheel of the motor vehicle, at least one wheel speed sensor, by means of which each rotational speed, also referred to as wheel speed, of each wheel is recorded. Based on each wheel speed, the speed can be determined respectively, at which the wheel rotates, respectively. If the speed is 0, for example, it can be recorded that the motor vehicle is at a standstill. Alternatively or additionally, the sensor device comprises, for example, at least one shaft speed sensor, by means of which a rotational speed of at least one shaft of the motor vehicle, also referred to as shaft rotational speed, is recorded. The shaft is, for example, a transmission shaft of a transmission of the motor vehicle. Furthermore, the shaft may be a pinion shaft of an engine designed for operating the motor vehicle. The engine is, for example, an internal combustion engine, in particular a reciprocating piston machine, or alternatively an electric motor, so that the motor vehicle is designed, for example, as a hybrid or electric vehicle. Based on the shaft rotational speed, a speed can be recorded, at which the shaft rotates. If the shaft rotational speed or the speed at which the shaft rotates, is 0, it can be assumed, for example, that the motor vehicle is at its standstill.

[0036] Furthermore, it is conceivable that the sensor device has at least one communication element which, for example, can communicate at least indirectly with satellites of a satellite-based navigation system. In this way it is possible, for example, by means of the communication element and by means of the satellite-based navigation system, to determine the speed, also referred to as driving speed, at which the vehicle moves, for example, on the earth or relative to the ground, so that based on the driving speed, it can be determined whether the motor vehicle is at its standstill or moves relative to the ground or along the ground.

[0037] As illustrated in the FIGURE by a dashed arrow 10, the sensor device provides, for example, in the first step S1, at least one, in particular an electrical signal, which characterizes the recorded or determined speed. The signal and thus the determined recorded speed are fed into, for example, a system or module 12, wherein the module 12 is realized, for example, by the electronic computing device. By means of module 12, a safe parking of the motor vehicle can be realized in such a way that the motor vehicle can be designed particularly cost and weight effectively.

[0038] As will be explained in more detail below, during the method, the parking lock is engaged, while by means of a braking device of the motor vehicle, the rolling away of the motor vehicle is at least restricted, in particular prevented. In order to be able to keep the weight and the cost of the motor vehicle particularly low, as the braking device, an additionally provided braking device of the motor vehicle, different from the service brake, the parking lock and the parking brake, is used.

[0039] In the following, for example, an error-free operation of the motor vehicle will be described. In the error-free operation, in the second step S2 of the method, the motor vehicle, for example, initially moving at a certain speed and thus moving relative to the ground, in particular automatically by means of the electronic computing device, is decelerated or slowed down, wherein, for example, the motor vehicle is decelerated or slowed down by means of the electronic stability program. In particular, the motor vehicle is braked to its standstill in the second step S2, for example. For this purpose, for example, the electronic computing device or the electronic stability program provide a decelerating request illustrated by arrow 16, to module 14, by means of which, for example, the motor vehicle is slowed down or decelerated, and thereby slowed down, in particular to a standstill. Module 14 is realized, for example, by the electronic computing device.

[0040] At the third step S3 of the method, it is determined or recognized that the speed of the motor vehicle falls below a predetermined threshold value or that the motor vehicle is at a standstill. Thus, for example, at the third step S3, it safely recognized that the motor vehicle is at its standstill. For example, it is recognized, based on said signal, that the speed, at which the motor vehicle moves along the ground, falls below the predetermined threshold value or that the motor vehicle is at its standstill. In the error-free operation, for example, based on the wheel speed sensors or based on the wheel speeds, it is recognized that the motor vehicle is at a standstill or that the speed of the motor vehicle falls below the threshold value.

[0041] At the fourth step S4 of the method, the standstill is maintained or the rolling away of the motor vehicle is at least restricted. For example, at the second step S2, if the motor vehicle is decelerated by means of the service brake and thus by means of a pressure of a brake fluid, also referred to as brake pressure, for example, in the fourth step S4, the motor vehicle is decelerated by means of the service brake and thus by means of a pressure of a brake fluid, also referred to as brake pressure, and, for example, in the fourth step S4, via valves of the electronic stability program, the brake pressure is locked or held until the particularly designed parking break as an electric parking brake is closed andor the parking lock is engaged. In other words, at the fourth step S4, in the error-free operation, the motor vehicle is kept at a standstill by means of the brake pressure while the parking lock is engaged andor the parking brake is closed.

[0042] At the fifth step S5 of the method, for example, the standstill of the motor vehicle is permanently secured. For this purpose, for example, at the fifth step S5 of the method, in the error-free operation, the hydraulic brake pressure is released or reduced, so that then the closed parking brake andor the engaged parking lock secure the standstill and thus the motor vehicle against undesired rolling away.

[0043] For this purpose, for example, there is a data exchange with modules 22 illustrated by arrows 18 and 20, by means of which, for example, the standstill is secured. Modules 22 are realized, for example, by the electronic computing device and are used, for example, to control at least one actuator of the parking brake andor at least one actuator of the parking lock, so that, for example, by means of each actuator, the parking brake or the parking lock can be closed or engaged. By arrow 18, for example, a request to modules 22 is illustrated, so that by means of the modules 22, for example, the parking brake is closed andor the parking lock is engaged. If this is successful, for example, a feedback illustrated by arrow 20 takes place in which the parking brake is closed or the parking lock is engaged.

[0044] In the following, an error or an error case of the motor vehicle is described. In this error case, for example, the parking brake has failed because, for example, the electronic stability program that controls the parking brake has failed. In the event of an error, for example, at the second step S2, the motor vehicle is, in particular automatically, decelerated by the electronic computing device, via the above-mentioned braking device, different from the service brake, the parking brake and the parking lock, and in particular slowed down to a standstill, particularly while the parking lock is still disengaged. For this purpose, the braking device comprises, for example, the above-mentioned electric motor designed for driving the motor vehicle andor a secondary brake system (SBS). In the event of an error, in the third step S3, the standstill of the motor vehicle or the circumstance that the speed of the motor vehicle falls below the threshold value, for example, is recognized via redundant wheel speed sensors connected to the secondary brake system andor by the fact, that a rotational speed of the above-mentioned engine, in particular a pinion shaft of the engine, is recorded andor that a transmission output speed of a transmission is recorded. Alternatively or additionally, at the third step S3, the standstill of the motor vehicle or the condition that the speed of the motor vehicle falls below the threshold value, can be recognized based on the speed of the motor vehicle, determined by means of the satellite-based navigation system.

[0045] In the event of an error, in the fourth step S4 of the method, the standstill is maintained or the motor vehicle is secured against excessive rolling or rolling away, while the braking device as a braking body at least restricts the rolling away of the motor vehicle. By restricting the rolling away of the motor vehicle, it can be understood that the rolling away or rolling of the motor vehicle is completely prevented, so that the motor vehicle does not move. Furthermore, by restricting the rolling away, it may be understood that a slight movement of the motor vehicle is permitted only at a low speed. In particular, for example, the rolling away of the motor vehicle can be at least restricted by means of the braking device in such a way that the braking device comprises the above-mentioned electric motor, by means of which at least one shaft of the motor vehicle is alternately rotated back and forth. In the event of an error, in the fourth step S4 of the method, the rolling away of the motor vehicle is at least restricted while the parking lock is engaged, wherein the rolling away of the motor vehicle is at least restricted until the parking lock is fully engaged.

[0046] In the event of an error, in the fourth step S5 of the method, the braking device is off or deactivated after the parking lock has been engaged, whereby the standstill and thus parking of the motor vehicle can be permanently secured by means of the parking lock.