SYSTEM ARCHITECTURE OF AN ELECTRONIC BRAKING SYSTEM

Abstract

A braking system for a vehicle, including: at least one pressure regulating module to set a setpoint brake pressure for at least one brake cylinder of a vehicle wheel; at least one wheel speed sensor to detect the wheel slip of the one vehicle wheel; at least one pressure control valve, assigned to the brake cylinder of a wheel, to control the brake pressure applied at the brake cylinder depending on the wheel slip; and a central processing unit to control the at least one pressure regulating module and the at least one pressure control valve at least starting from a brake signal and the detected data of the at least one wheel speed sensor, which has a direct connection to the central processing unit to transmit data detected by the wheel speed sensor.

Claims

1-7. (canceled)

8. A braking system for a vehicle, comprising: at least one pressure regulating module to set a setpoint brake pressure to be introduced into at least one brake cylinder of a wheel of the vehicle; at least one wheel speed sensor to detect the wheel slip of the one wheel of the vehicle; at least one pressure control valve, which is assigned to the brake cylinder of a wheel, to control the brake pressure applied at the brake cylinder in dependence on the wheel slip; and a central processing unit to control the at least one pressure regulating module and the at least one pressure control valve at least starting from a brake signal and the detected data of the at least one wheel speed sensor; wherein the at least one wheel speed sensor has a direct connection to the central processing unit to transmit data detected by the wheel speed sensor.

9. The braking system of claim 8, wherein the central processing unit and the at least one pressure regulating module are arranged in a central unit.

10. The braking system of claim 9, wherein the central processing unit and the at least one pressure regulating module have a common housing.

11. The braking system of claim 8, wherein the braking system has a wheel speed sensor for each wheel to be braked of the vehicle.

12. The braking system of claim 8, wherein the braking system has a pressure control valve for each brake cylinder to be controlled of a wheel of the vehicle.

13. The braking system of claim 8, wherein the braking system has at least one further sensor, which is a sensor for detecting the brake pressure, wherein the at least one further sensor also has a connection to the central processing unit, which is configured to transmit data directly.

14. The braking system of claim 8, wherein the braking system has multiple pressure regulating modules and at least one pressure regulating module for each axle or for each double axle of the vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 shows a schematic structure of an electronic braking system according to the prior art.

[0021] FIG. 2 shows a schematic structure of an embodiment of an electronic braking system according to the invention.

[0022] FIG. 3 shows a schematic structure of the embodiment from FIG. 2 in a utility vehicle.

DETAILED DESCRIPTION

[0023] FIG. 1 shows the schematic structure of an electronic braking system according to the prior art.

[0024] The control unit 60 is connected to a power supply 20 and controls the four pressure control valves 40, which are each assigned to one wheel of the vehicle, via electronic switches 41. Moreover, the control unit 60 also controls the pressure regulating module 30. The data transmission is ensured here by a CAN bus 70. Of course, other forms of data transmission are also conceivable. The power supply of the pressure regulating module 30 is also ensured via the power supply 20 of the control unit 60. Furthermore, wheel speed sensors 50 detect the speeds of the wheels of the vehicle, wherein each sensor is assigned to one wheel and detects its speed. The wheel speed sensors 50 are not directly connected to the control unit 60 here, but rather communicate via the pressure regulating module 30.

[0025] If one of the wheel speed sensors 50 detects slip between a wheel of the vehicle and the roadway during braking of the vehicle, these items of information are conducted to the control unit 60 via the pressure regulating module 30. The pressure control valve 40 corresponding to the wheel at which the slip was established is controlled at the pressure regulating module in such a way that the brake pressure of the relevant brake cylinder 85 is reduced until slip is no longer established by the wheel speed sensor 50 and the traction is established again. An ABS braking action takes place.

[0026] A similar functional principle is applied if a wheel speed sensor 50 should establish a slip during the acceleration of the vehicle. In this case, the pressure applied at the corresponding brake cylinder is increased by the central control unit 60 and the spinning wheel is thus braked, so that slip does not occur.

[0027] In the event of a failure of the pressure regulating module 30, for example, due to an electrical disturbance, in previous systems, data can no longer be transmitted from the wheel speed sensors 50 to the control unit 60. The control unit 60 therefore also cannot control the pressure control valves 40 so that an ABS braking action or a traction control can take place, which as already described above can have negative effects on the vehicle stability and thus the safety of the vehicle, in particular during braking.

[0028] The designation “failure of a pressure regulating module” is understood in the scope of this application to mean that the electronic part of the pressure regulating module 30 fails or, for example, has to be switched off by the ECU due to an occurring defect, so that the control unit 60 can no longer be incorporated in the provision of the brake pressure. Electronic braking systems known from the prior art have a pneumatic replacement system (backup) for this case. The braking intention of the driver is converted here via the existing foot brake module 83 into a pneumatic control pressure, in dependence on which the brake pressure is then generated in the pressure regulating module 30. In this way, a variable brake pressure can still be made available at the brake cylinders 85 of the vehicle, even if the central control unit 60 cannot be incorporated in the control of the brake pressure. However, an ABS braking action or a traction control are no longer possible.

[0029] FIG. 2 shows the schematic structure of an embodiment of the electronic braking system according to the invention. The components of the EBS (pressure regulating module 30, pressure control valves 40, central control unit 60) are arranged in a central unit 10 here. Embodiments in which the pressure control valves 40 are arranged outside the braking module 10, but are nonetheless still directly activated by the control unit 60, are also conceivable and typical in practice, however.

[0030] In contrast to the system architecture of the EBS shown in FIG. 1, the wheel speed sensors 50 are connected directly to the central unit 10. This is to be understood to mean that due to the direct connection, they are capable of being able to transmit their data directly to the control unit 60, without firstly conducting these data to the pressure regulating module 30, as in the arrangement of FIG. 1. The data of the wheel speed sensors 50 are thus available to the control unit 60 even if the pressure regulating module 30 fails or is switched off. The control unit can thus still intervene in the braking system and an ABS braking action and traction control are thus possible on the basis of the sensor data, which are now available to the control unit 60, via the pressure control valves 40, due to which the braking performance and the controllability of the braking or the traction and the controllability of the vehicle during starting/acceleration and thus the safety of the vehicle can be improved.

[0031] FIG. 3 shows the schematic structure of an embodiment of the system architecture according to the invention of an electronic braking system in a vehicle. The vehicle is a two-axle utility vehicle, which has twin wheels (84c, 84d) on the rear axle. Of course, the application of the invention to a vehicle which does not have twin wheels on the rear axle is also possible.

[0032] Each of the wheels (84a, 84b, 84c, 84d) is respectively assigned one brake cylinder (85a, 85b, 85c, 85d) and the front wheels (84a, 84b) are additionally each assigned a pressure control valve (40a, 40b). Moreover, one wheel speed sensor (50a, 50b, 50c, 50d) is respectively located on each wheel (84a, 84b, 84c, 84d), which detects the speed of the corresponding wheel. It is to be noted that the invention is of course not limited to the use of only two pressure control valves, rather embodiments are also possible in which each wheel of the vehicle has a pressure control valve. The pressure control valves (40a, 40b) are located in the pressure line (82ab) between a pressure regulating module 30 and the brake cylinders of the front wheels (84a, 84b), wherein the pressure regulating module 30 is in turn connected to the pressure accumulator 81 via the reservoir line 82. The pressure line 82ab is a single-channel pressure line which transmits the same brake pressure to the brake cylinders 85a and 85b. The pressure lines 82c and 82d are separate pressure lines, by which different brake pressures can be conducted to the brake cylinders 85d or 85c of the rear wheels (84c, 84d), respectively. The pressure regulating module 30 used in the embodiment of FIG. 3 is thus a pressure regulating module having three channels. It is to be noted that in other embodiments multiple individual pressure regulating modules 30 can also be used, for example, one two-channel module for each axle, which can then provide different brake pressures at the brake cylinders of the individual wheels.

[0033] Furthermore, the pressure module 30 is located together with the control unit 60 in a central unit 10. Moreover, an electrical connection between the wheel speed sensors (50a, 50b, 50c, 50d) and the control unit 60 exists via the sensor line 71, via which the data acquired by the sensors can be transmitted directly to the control unit 60. The central unit 60 can activate the pressure control valves (40a, 40b) in accordance with the braking requirements and wheel speeds. Moreover, the electronic braking system shown in FIG. 3 has a foot brake module 83, which can transmit items of information to the control unit 60 via a brake line 73.

[0034] If the vehicle driver wishes to brake the vehicle, he actuates the foot brake module 83. The actuation is converted there as a function of the actuation intensity into a brake signal and transmitted via the brake line 73 to the control unit 60. The brake signal is used there in consideration of various factors, for example, the vehicle mass or the axle load distribution, to calculate a setpoint brake pressure, which is to be conducted to the brake cylinders (85a, 85b, 85c, 85d) of the four wheels of the vehicle, so that the vehicle decelerates according to the intensity specified by the driver.

[0035] Subsequently, the pressure regulating module 30 is controlled by the control unit 60 in such a way that it sets the required setpoint brake pressure. This is then conducted via the pressure lines (82ab, 82c, 82d) to the brake cylinders (85a, 85b, 85c, 85d), by which these are actuated and the vehicle is braked. It is to be noted that embodiments are also conceivable or even advantageous in which a separate setpoint brake pressure is calculated per vehicle axle or even per vehicle wheel, so that each wheel is operated using the respective optimum brake pressure.

[0036] The wheel speed sensors (50a, 50b) detect the speeds of the corresponding front wheels (84a, 84b) of the vehicle and transmit them via the sensor line 71 directly to the control unit 60. If this control unit recognizes slip during the braking at a wheel on the basis of the sensor data, it activates the corresponding pressure control valve (40a, 40b) of the respective wheel (84a, 84b) via the activation line 72 to reduce the brake pressure applied at the corresponding brake cylinder (85a, 85b), until slip is no longer recognized, to thus carry out ABS braking. If slip is recognized during the acceleration process, the traction control is carried out as described above with respect to FIG. 1.

[0037] In the illustrated system architecture according to the invention it is thus possible due to the wheel speed sensors (50a, 50b, 50c, 50d) connected directly to the ECU 60 to carry out ABS braking or traction control at the control unit 60, even if the pressure regulating module 30 has failed and can no longer communicate with the control unit 60.

THE LIST OF REFERENCE SIGNS IS AS FOLLOWS

[0038] 10 central unit

[0039] 20 power supply

[0040] 30 pressure regulating module (EPM)

[0041] 40, 40a, 40b pressure control valve (PCV)

[0042] 41 switch

[0043] 50, 50a, 50b, 50c, 50d wheel speed sensor (WSS)

[0044] 60 control unit (ECU)

[0045] 70 data transmission line (for example, CAN)

[0046] 71 sensor line

[0047] 72 activation line (PCVs)

[0048] 73 brake line

[0049] 80 vehicle

[0050] 81 pressure reservoir container

[0051] 82 reservoir line

[0052] 82ab pressure line (EPM to brake cylinders of the front axle)

[0053] 82c, 82d pressure line (EPM to brake cylinders of the rear axle)

[0054] 83 foot brake module

[0055] 84a, 84b vehicle wheel at front axle

[0056] 84c, 84d vehicle wheel at rear axle

[0057] 85a, 85b, 85c, 85d brake cylinder