METHOD FOR BRAKING A VEHICLE, AND DRIVE TRAIN OF A VEHICLE

Abstract

A drive train of a vehicle and a method for controlling a drive train is provided. The drive train includes a brake control unit configured to control vehicle brakes via, for example, hydraulic lines, and a transmission control unit coupled to the brake control unit via a data bus and configured to control a vehicle transmission. The transmission control unit is configured to command the brake control unit to activate the vehicle brakes in response to a detected defect in the vehicle transmission.

Claims

1. A method for braking a vehicle, the vehicle having a transmission which is actuated by a transmission control unit, wherein the transmission control unit requests a brake intervention.

2. The method as claimed in claim 1, wherein the brake intervention is requested electronically by the transmission control unit and is implemented by a vehicle brake.

3. The method as claimed in claim 2, wherein the transmission control unit requests the brake intervention by a brake control unit which converts the request into a torque of at least one wheel brake which is configured as a vehicle brake.

4. The method as claimed in claim 2, wherein the transmission control unit and the brake control unit communicate via a bus system of the vehicle.

5. The method as claimed in claim 2, wherein, before the communication between the transmission control unit and the brake control unit, the driving situation of the vehicle is checked in order to prevent an impermissible brake intervention.

6. A drive train of a vehicle, in the case of which an engine drives wheels of the vehicle via a transmission, the transmission being actuated by a transmission control unit, and the vehicle having a vehicle brake which is controlled by a brake control unit in order to brake the vehicle, wherein the transmission control unit for electronically requesting a brake intervention is connected directly to the brake control unit for actuating the vehicle brake.

7. The drive train as claimed in claim 6, wherein, in the case of a hybrid vehicle, the transmission is configured as a hybrid transmission structure.

8. The drive train as claimed in claim 6, wherein the transmission control unit and the brake control unit are connected to one another via a data line.

9. The drive train as claimed in claim 6, wherein the brake control unit is configured as an ABS control unit or an ESP control unit or an ASR control unit.

10. A drive train of a vehicle, the drive train comprising: a brake control unit configured to control vehicle brakes via hydraulic lines; and a transmission control unit coupled to the brake control unit via a data bus and configured to control a vehicle transmission, wherein the transmission control unit is further configured to command the brake control unit to activate the vehicle brakes in response to a detected defect in the vehicle transmission.

11. The drive train of claim 10, wherein the transmission control unit commands the brake control unit to activate the vehicle brakes in response to the vehicle operating in a safe driving situation.

12. The drive train of claim 10, wherein the detected detect includes a detection that a gear in vehicle transmission is unable to be disengaged.

13. The drive train of claim. 12, wherein the vehicle transmission is a double clutch transmission and the gear is a component within the double clutch transmission.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosure permits numerous embodiments. One of these is to be described in greater detail on the basis of the figures which are shown in the drawing, in which:

[0017] The Figure shows one exemplary embodiment of a drive train of a vehicle.

DETAILED DESCRIPTION

[0018] The Figure shows one exemplary embodiment of a drive train 1 of a vehicle, in the case of which a transmission 2 is actuated by way of a transmission control unit 3. Here, the transmission 2 is connected via a differential 4 to vehicle wheels 5. Via a data bus 6, for example a CAN bus, the transmission control unit 3 is connected to a brake control unit 7, for example an ABS control unit. The brake control unit 7 of a brake actuator (not shown in further detail) is coupled via corresponding hydraulic lines 8 to in each case one of the wheel brakes 9 which lie opposite the vehicle wheel 5.

[0019] If a defect occurs in the transmission 2, which defect can consist in the case of a double clutch transmission for example in that a gear cannot be disengaged on a component transmission of the double clutch transmission, the vehicle rolls further and continues to accelerate, which involves a risk of an accident in the absence of a brake intervention. Said defect is detected by the transmission control unit 3. In this case, the transmission control unit 3 requests a brake intervention electronically by the brake control unit 7, in order for it to be possible for a controlling intervention of the transmission 2 to be performed. The brake control unit 7 converts the request of the transmission control unit 3 into a torque which is set at the wheel brakes 9, as a result of which the vehicle wheels 5 are braked by way of the wheel brakes 9.

[0020] Before the request of the brake intervention is output by way of the transmission control unit 3 to the brake control unit 7, the transmission control unit 3 checks whether the vehicle is in a driving situation, in which the brake intervention ensures reliable and accident-free braking of the vehicle. If said check leads to the result that a brake operation brings about an unsafe driving situation of the vehicle, the request of the brake intervention is not output to the brake control unit 7.

[0021] The request of a brake intervention by way of the transmission control unit 3 can also take place, however, in fault-free operation of the transmission 2. This is the case, fur example, in a transmission 2 which comprises a claw which becomes torque-free when the output is torque-free. A claw of this type can be opened only when it is torque-free. In the overrun mode of the vehicle, the claw is loaded and therefore cannot be opened. As a result of a brake request of the transmission control unit 3, however, the overrun torque of the vehicle wheels 5 can be conducted past the transmission 2 which has the claw into the vehicle brake 9 by way of the brake intervention. The transmission 2 and the claw are torque-free at that moment, and the claw can then be opened.

[0022] The vehicle drive train 1 which is shown in the figure comprises a front transversely mounted transmission. The invention is not restricted to a transmission of this type, however, but rather can be applied to all drive designs such as a standard drive, an all wheel drive and the like.

LIST OF DESIGNATIONS

[0023] Drive train

[0024] Transmission

[0025] Transmission control unit

[0026] Differential

[0027] Vehicle wheel

[0028] Data bus

[0029] Brake control unit

[0030] Hydraulic line

[0031] Wheel brake