METHOD FOR OPERATING A BRAKE SYSTEM WITH INCREASED SAFETY IN THE FALLBACK LEVEL AND BRAKE SYSTEM WITH INCREASED SAFETY IN THE FALLBACK LEVEL
The embodiments generally relate to a method for operating a brake system with increased safety in the fallback level, and to such a brake system for a motor vehicle. Here, the brake system may comprise a brake system which requires no operating fluids. Here, the method for operating the brake system provides for actuating wheel brake modules of the motor vehicle in a normal operating level by a central control electronics unit, and for actuating the wheel brake modules in a fallback level, wherein the fallback level is designed in a two-circuit manner.
1 . A method for operating a brake system for a motor vehicle comprising:
determining actuating information describing a brake demand by a brake actuating unit, wherein the brake demand can be detected by at least one front axle pedal sensor and one rear axle pedal sensor independently of each other;
generating first font axle and rear axle brake torque demands corresponding to the actuating information with a central control electronics unit;
generating second front axle brake torque demands corresponding to the actuating information by at least one front axle brake control unit which is assigned to wheel brake modules of a front axle, or which is assigned to two diagonally arranged wheel brake modules,
generating second rear axle brake torque demands corresponding to the actuating information by at least one rear axle brake control unit which is assigned to wheel brake modules of a rear axle, or which is assigned to two other diagonally arranged wheel brake modules, and
actuating the wheel brake modules of the brake system according to one of:
a normal operating level with the first front axle and rear axle brake torque demands,
a fallback level with the second front axle brake torque demands front axle, and
a fallback level with the second rear axle brake torque demands.
2 . The method for operating a brake system as claimed in claim 1 , wherein the brake system further comprises:
at least one first brake request signal line between the front axle pedal sensor and the front axle brake control unit,
at least one second brake request signal line between the rear axle pedal sensor and the rear axle brake control unit,
at least one data line between the at least one central control electronics unit and the front axle brake control unit, and at least one data line between the at least one central control electronics unit and the rear axle brake control unit.
3 . The method as claimed in further comprising:
switching between the normal operating level and the fallback level by a decision logic unit, wherein the decision logic unit integrated into one of the front axle and the rear axle brake control unit.
4 . The method as claimed in claim 1 further comprising:
actuating the wheel brake modules in the normal operating level when
the first front axle and rear axle brake torque demands exist and actuating information of at least one front axle and rear axle pedal sensor is available,
there is no error message from the central control electronics unit, and
the first front axle and rear axle brake torque demands do not exceed a predefined offset from the corresponding second front axle and rear axle brake torque demands.
5 . The method as claimed in claim 1 further comprising:
actuating the wheel brake modules in the fallback level when one of:
actuating information of at least one front axle or rear axle pedal sensor is available, but no first front axle or rear axle brake torque demands by the central control electronics unit exist,
in the case of actuating information by the actuating unit being present, there is an error message from the central control electronics unit,
in the case of actuating information by the actuating unit being present, there is no bus signal on at least data line,
the first front axle or rear axle brake torque demands exceed a predefined offset from the corresponding second front axle or rear axle brake torque demands.
6 . The method as claimed in claim 1 , further comprising at least one of:
transmitting the actuating information independently of one another from the front axle pedal sensor to the front axle brake control unit via a first brake request signal line and from the rear axle pedal sensor to the rear axle brake control unit via a second brake request signal line,
transmitting the actuating information in each case independently of each other via the front axle and rear axle brake control unit by at least one data line to the at least one central control electronics unit,
transmitting the first front axle or rear axle brake torque demands independently of each other via the at least one data line to the front axle and rear axle brake control units.
7 . The method as claimed in claim 1 , further comprising:
generating the first front axle or rear axle brake torque demands according to central control algorithms stored in the central control electronics unit.
8 . The method as claimed in claim 1 , wherein the central control electronics unit is connected via a data bus to a vehicle computer, and wherein the generation of the first front axle or rear axle brake torque demands is at least partially based on signals which are transmitted via the data bus to the central control electronics unit.
9 . The method as claimed in claim 8 , wherein the data bus is connected to a parking brake button, and wherein the central control electronics unit can be actuated via the parking brake button.
10 . The method as claimed in claim 1 , further comprising:
generating the brake torque demands according to stored local control algorithms by the brake control units.
11 . The method as claimed in claim 1 , wherein the central control electronics unit comprises an front axle partition and an rear axle partition which independently generate the first front axle or rear axle brake torque demands, further comprising:
generating the first front axle brake torque demands by the front axle partition and transmitting them via the data line to the front axle brake control unit,
generating the first rear axle brake torque demands by the rear axle partition and transmitting them via the data line to the rear axle brake control unit.
12 . The method as claimed in claim 1 , wherein at least one of the front axle brake control unit and the rear axle brake control unit is of split configuration and is each directly assigned to a wheel brake module.
13 . The method as claimed in claim 1 , further comprising:
transmitting the actuating information from the front axle and rear axle pedal sensors to the central control electronics unit solely via the first and second brake request signal line to the front axle and rear axle brake control units and from there via at least one data line.
14 . The method as claimed in claim 1 , wherein, in the fallback level, the actuating of the wheel brakes takes place solely by the brake actuating unit without further communication via a data bus.
15 . The method as claimed in claim 1 , wherein, furthermore, an additional data line is provided between the front axle and rear axle brake control unit, which enables data exchange between the front axle and the rear axle brake control unit.
16 . A brake system for a motor vehicle comprising:
a plurality of front axle brake wheel brake modules;
a plurality of rear axle wheel brake modules;
a brake actuating unit for determining actuating information describing a brake demand, wherein the brake demand can be detected by at least one front axle pedal sensor and one rear axle pedal sensor independently of each other;
an central control unit with instructions for generating first front axle and rear axle brake torque demands corresponding to the actuating information;
at least one front axle brake control unit with instructions for generating second front axle brake torque demands corresponding to the actuating information by which is assigned to wheel brake modules of a front axle, or which is assigned to two diagonally arranged wheel brake modules,
at least one rear axle brake control unit with instructions for generating second rear axle brake torque demands corresponding to the actuating information by which is assigned to wheel brake modules of a rear axle, or which is assigned to two other diagonally arranged wheel brake modules, and
wherein the brake actuation unit actuates the plurality of front axle and rear axle wheel brake modules of the brake system according to one of:
a normal operating level with the first front axle and rear axle brake torque demands,
a fallback level with the second front axle brake torque demands front axle, and
a fallback level with the second rear axle brake torque demands.
17 . The brake system as claimed in claim 16 ,
wherein the plurality of front axle and rear axle wheel brake modules, each comprise a wheel brake,
wherein the brake actuating unit has at least one front axle pedal sensor and one rear axle pedal sensor, each of which is designed to detect actuating information, describing the brake demand, of the brake actuating unit independently of one another,
wherein the front axle pedal sensor is connected at least to the front axle brake control unit, via at least one first brake request signal line,
wherein the rear axle pedal sensor is connected at least to the rear axle brake control unit via at least one second brake request signal line, and
wherein the at least one central control electronics unit is connected via at least one data line to the front axle brake control unit and via at least one data line to the rear axle brake control unit.
18 . The brake system as claimed in claim 16 , wherein the central control electronics unit comprises a front axle partition and a rear axle partition, and wherein the front axle partition is configured to generate a first front axle brake torque demand of the first brake torque demands independently of the rear axle partition and to transmit the first front axle demand via the at least one data line to the front axle brake control unit, and wherein the rear axle partition is configured to generate a first rear axle brake torque demand of the first brake torque demands independently of the front axle partition and to transmit it via another of the at least one data line to the rear axle brake control unit.
19 . The brake system as claimed in claim 16 , wherein the at least one date line comprises a further data line provided between the central control electronics unit and a higher-level vehicle computer, and wherein the central control electronics unit is configured to be able to be actuated by the vehicle computer.
20 . The brake system as claimed in claim 19 , wherein a parking brake button is connected via the further data line to the central control electronics unit, and wherein the central control electronics unit is configured to be able to be actuated by the parking brake button.
21 . The brake system as claimed in claim 16 , wherein an additional signal line is provided between the central control electronics unit and at least one of the front axle brake control unit and the rear axle brake control unit, and wherein the signal line is connected to an emergency stop switch.
22 . The brake system as claimed in one of the preceding claim 16 , wherein the front axle brake control unit and the rear axle brake control unit each have two different power supplies.