Method for safely heating at least one brake disc of a vehicle

Abstract

The present invention comprises a method (100) for safely heating at least one brake disc (30) of a vehicle (80), comprising the following steps: - Setting (102) an actual pressure (40) to a first target pressure (42) for the at least one brake disc (30), wherein the actual pressure (40) specifies a defined pressure of at least one brake pad (32) on the at least one brake disc (30) of the vehicle (80), wherein the actual pressure (40) is set at least partially indirectly on the basis of a motion-specific parameter (50) of the vehicle (80); - Maintaining (104) the set actual pressure (40) for a first time interval t1 (47) in order to heat up at least one brake disc (30); - Reducing (106) the actual pressure (40) to a second target pressure (46) within a second time period t2 (48).

Description

[0001] The present invention relates to a method for safely heating at least one brake disc of a vehicle. State of the art

[0002] So-called residual-drag-optimized brakes are installed, particularly in electric vehicles. These types of brakes reduce friction loss when not braking and significantly increase the range of the vehicles.

[0003] However, this brake optimization results in a layer of ice forming on the brake disc at low temperatures, such as around freezing point. As a result, reliable hydraulic braking can no longer be guaranteed under all weather conditions.

[0004] Ice formation occurs primarily during changes in temperature and humidity, such as in a tunnel or when entering an underground parking garage. Periodic hydraulic deceleration at low temperatures can heat the brake discs, thus preventing ice formation. This periodic hydraulic deceleration must occur at a low pressure range for efficiency and comfort reasons.

[0005] To ensure that the brakes are heated, it is therefore necessary to reliably detect the contact of the brake pads. This has traditionally been achieved using pressure sensors. However, the measurement accuracy of existing pressure sensors, as guaranteed by the well-known ASIL (Automotive Safety Integrity Level) safety standard, lies within a range that is noticeable to the driver and is therefore too imprecise for this application. A solution using pressure sensors alone is therefore not feasible without significantly compromising comfort. Disclosure of the invention

[0006] Therefore, the invention provides a method for safely heating at least one brake disc of a vehicle having the features of the independent claim.

[0007] According to a first aspect, the disclosure relates to a method for safely heating at least one brake disc of a vehicle.

[0008] In a first step, an actual pressure is set to a first target pressure for the at least one brake disc, wherein the actual pressure indicates a defined pressure of at least one brake pad on the at least one brake disc of the vehicle, wherein the actual pressure is set at least partially indirectly on the basis of a movement-specific parameter of the vehicle.

[0009] In a second step, the set actual pressure is maintained for a first time period t1 in order to heat up at least one brake disc.

[0010] In a third step, the actual pressure is reduced to a second target pressure within a second time period t2.

[0011] The actual pressure is the pressure actually acting on the at least one brake disc. Thus, adjusting the actual pressure can, for example, involve controlling the vehicle and / or the vehicle's braking system in such a way that the actual pressure acts on the brake disc. The same applies to maintaining and reducing the actual pressure.

[0012] A fundamental idea of ​​the present invention is that an exact, safe application of a brake pad (brake pad) for heating a brake disc is not only detected or measured by using a pressure sensor, but that a pressure required for the brake disc and acting on the brake disc by applying pressure is set at least partially indirectly on the basis of a movement-specific parameter of the vehicle, such as a deceleration of the vehicle or information about a wheel speed of the vehicle.

[0013] The present pressure-based solution, which involves applying a brake pad to the vehicle's brake disc, e.g. by automatically decelerating the vehicle, creates a measurable "jerk" in the vehicle, which, although not noticeable to the driver, can nevertheless be measured.

[0014] In this way, the application of the brake pads and thus the heating of the vehicle's brake disc can be detected safely and reliably.

[0015] One possible embodiment of the method provides for the motion-specific parameter to include at least one of the following auxiliary variables: a negative acceleration of the vehicle, a wheel speed of at least one wheel of the vehicle. This provides the advantage of reliably and reliably detecting brake disc heating.

[0016] A possible embodiment of the method provides that the set actual pressure is between a first minimum pressure P min , which allows the vehicle-specific parameter to be determined, and a second maximum pressure P max , which does not yet produce a perceptible reaction from the vehicle during braking. This increases driving comfort for the driver.

[0017] One possible embodiment of the method provides that the first time period t1, during which the actual pressure is kept constant, and / or the number of times the method is performed within a defined time period t3, depends on an environment-specific parameter of the vehicle. This provides the advantage that the vehicle's brake disc is heated efficiently and reliably adapted to changing ambient conditions.

[0018] One possible embodiment of the method provides for the environment-specific parameter to represent an outside temperature in the immediate vicinity of the vehicle. This has the advantage of adapting the heating of the vehicle's brake disc to the prevailing ambient conditions, thus enabling efficient implementation of the method.

[0019] One possible embodiment of the method provides for the actual pressure to be adjusted using a pressure sensor-based device. This provides the advantage of enabling reliable and efficient heating of the brake disc.

[0020] A possible embodiment of the method provides that, after the step of reducing the set actual pressure, a step of resetting the pressure sensor-based device to an initial configuration corresponding to a state without pressure being applied to the at least one brake disc. This ensures that precise and reliable application of the brake pads is detected at all times, enabling safe heating of the brake disc.

[0021] One possible design of the process provides for the setting and reduction of the actual pressure to occur evenly. This increases the vehicle's driving comfort.

[0022] According to a second aspect, the disclosure relates to a computer program containing machine-readable instructions which, when executed on one or more computers and / or compute instances, cause the computer(s) or compute instance(s) to carry out the method according to the invention.

[0023] According to a third aspect, the disclosure relates to a machine-readable data carrier and / or download product comprising the computer program.

[0024] According to a fourth aspect, the disclosure relates to one or more computers and / or compute instances with the computer program, and / or with the machine-readable data carrier and / or the download product.

[0025] Further measures improving the invention are presented in more detail below together with the description of the preferred embodiments of the invention with reference to figures. Examples of implementation

[0026] It shows: Fig. 1 Schematic flow diagram of the method 100 for safely heating at least one brake disc 30 of a vehicle 80; and Fig. 2 Schematic curve of a pressure applied to a brake disc 30 and a corresponding curve of a movement-specific parameter over time according to an embodiment of the present invention.

[0027] The Fig. 1 shows a schematic flow diagram of the method 100 for safely heating at least one brake disc 30 of a vehicle 80. The vehicle 80 can preferably be an automobile, a motorcycle, or an electric vehicle.

[0028] In step 102, an actual pressure 40 is set to a first target pressure 42 for the at least one brake disc 30. The actual pressure 40 indicates a defined pressure of at least one brake pad 32 on the at least one brake disc 30 of the vehicle 80. The actual pressure 40 is set at least partially indirectly based on a movement-specific parameter 50 of the vehicle 80.

[0029] The temporal course of the movement-specific parameter 50 corresponds to the temporal course of the actual pressure 40 (see also Fig. 2).

[0030] The movement-specific parameter 50 can comprise at least one of the following auxiliary variables: a negative acceleration of the vehicle 80, a wheel speed of at least one wheel of the vehicle 80.

[0031] In step 104, the set actual pressure 40 is maintained for a first time period t1 47 in order to heat up the at least one brake disc 30.

[0032] In step 106, the actual pressure 40 is reduced to a second target pressure 46 within a second time period t2 48.

[0033] Optionally, the set actual pressure 40 moves between a first minimum pressure P min in order to determine the vehicle-specific parameter 50, and a second maximum pressure P max so as not to produce any perceptible reaction of the vehicle 50, such as a jerk that is noticeable or perceptible to the driver of the vehicle 80, during the braking process.

[0034] Optionally, the first time period t1 47, during which the actual pressure 40 is kept constant, and / or the number of times the procedure is performed within a defined time period t3 49, depends on an environment-specific parameter 60 of the vehicle 80. It should also be noted that during active braking, whether by a driver or by the system, which involves hydraulic deceleration, additional energy is also introduced into the system. This heating reduces the need to heat the brake discs outside of active braking.

[0035] The environment-specific parameter 60 can represent an outside temperature in the immediate vicinity of the vehicle 80. This parameter 60 can preferably be determined via a vehicle-specific sensor of the vehicle 80. Alternatively, however, an embodiment without a corresponding temperature sensor within the vehicle 80 is conceivable if, for example, a temperature model determined through test series or empirical values ​​is stored in the vehicle or control unit of the vehicle 80 via a corresponding application via software in order to carry out the method according to the invention efficiently and depending on varying ambient conditions of the vehicle 80 - which can be determined with or without an additional temperature sensor.

[0036] Optionally, the actual pressure 40 is also adjusted using a pressure sensor-based device 39. This device 39 can be part of the vehicle 80.

[0037] Optionally, after the step of reducing 106 the set actual pressure 40, a step 108 of resetting the pressure sensor-based device 39 to an initial configuration 62 can be performed, which corresponds to a state without pressure being applied to the at least one brake disc 30, for example, a zero value of 0 bar. This can also be considered a type of recalibration of the device 39.

[0038] The method according to the invention can provide any number of repetitions of steps 102 to 106. Before each run or pass, the pressure sensor-based device 39 can be reset, for example, by a corresponding offset compensation, so that a corresponding sensor actually indicates 0 bar again in the pressureless state.

[0039] Optionally and particularly advantageously, the actual pressure 40 is set or built up to the defined target pressure 42 and the set actual pressure 40 is reduced evenly, i.e., at a constant rate. A slow reduction of the set actual pressure 40, i.e., a reduction of the actual pressure 40, for example, preferably in the millisecond range, is advantageous. The same applies to the slow buildup of the actual pressure 40.

[0040] The Fig. 2 shows a schematic curve of a pressure applied to a brake disc 30 of a vehicle 80 and a corresponding curve of a movement-specific parameter 50 over time according to an embodiment of the present invention.

[0041] In the temporal progression shown, the x-axis 18 represents the time and the y-axis 19 represents the respective height of the pressure curve 21 or the negative acceleration or deceleration curve 20.

[0042] Between the first time 22 and the second time 23, the vehicle's brake disc 30 is subjected to a defined pressure. This cannot be measured directly and precisely using a pressure sensor.

[0043] However, this can be indirectly determined by measuring a movement-specific parameter 50, a deceleration or negative acceleration of a wheel of the vehicle 80, to what extent a brake pad placed on the brake disc 30 exerts a corresponding necessary pressure. A course of the deceleration curve 20 corresponding to the pressure curve 21 is shown in the Fig. 2.

[0044] Between the second time 23 and the third time 24, the pressure on the brake disc 30 is continuously increased until an actual pressure 40 has reached a defined target pressure 42. To the same extent, the course of the negative acceleration of the curve 20 in the Fig. 2, which is measured accordingly.

[0045] In the present invention, therefore, the exact actual pressure value is not measured, but a target pressure 42 is determined indirectly via the movement-specific parameter 50, as shown here in Fig. 2, for example, the negative acceleration is determined or set. This allows for reliable detection of the brake pads on the brake disc 30, thus enabling reliable heating of the brake disc 30.

[0046] Between the third time 24 and the fourth time 25, which define a first time period t1 47, the set actual pressure 40 on the brake disc 30 is maintained constant for a defined time period in order to heat the brake disc 30. The deceleration also remains constant during this time period, as in the Fig. 2 is shown.

[0047] The actual pressure 40, which is set to a target pressure 42 and constantly maintained, moves between a first minimum pressure P min in order to be able to determine the vehicle-specific parameter 50 by measurement, and a second maximum pressure P max in order not to produce any perceptible reaction of the vehicle 50 during the automated controlled braking process of the vehicle 50. The setting of the required actual pressure 40, which is between P min and P max depends on various factors that may be vehicle-specific and / or environmental. A movement of the actual pressure 40 between P min and P max However, it is not understood that the actual pressure 40 during the first time period t1 47 of P min to P max Rather, it means that an absolute level of the actual pressure 40 between P min and P maxDuring the first time period t1 47, the actual pressure 40 remains constant as specified.

[0048] Between the fourth time 25 and the fifth time 26, which define a second time period t2 48, the set target pressure 42 is then reduced—preferably evenly, constantly, and slowly or in a controlled manner—to a defined initial pressure value, which is generally equivalent to a pressure value of 0 bar, and no pressure is exerted on the brake disc 30. Reducing the set actual pressure 40 is also necessary and required to prevent the brake disc 30 from permanently heating up, as this, among other things, impairs deceleration. Particularly in an electric vehicle, permanent heating of the brake disc leads to energy losses and thus to an undesirable reduction in range.

[0049] The third time period t3 49 between the first time 22 and the fifth time 26, in which the described process of pressurizing and releasing pressure on the brake disc 30 takes place, is variably adjustable and repeatable in its number, depending on the prevailing weather conditions, in order to avoid possible ice formation on the brake disc 30 or to counteract this ice formation.

[0050] The frequency of activation of the adjustable pressure profile is therefore variably adjustable. For example, at an outside temperature of 0 degrees Celsius, a constant actual pressure of 40 is applied to the brake disc 30 for 1 second once per minute. At an outside temperature of minus 30 degrees Celsius, however, it may be necessary to maintain a constant actual pressure of 40 three times per minute for three seconds in order to reliably heat the brake disc 30 of the vehicle 80.

Claims

[1] Method (100) for safely heating at least one brake disc (30) of a vehicle (80), comprising the following steps: - setting (102) an actual pressure (40) to a first target pressure (42) for the at least one brake disc (30), wherein the actual pressure (40) indicates a defined pressure of at least one brake pad (32) on the at least one brake disc (30) of the vehicle (80), wherein the actual pressure (40) is set at least partially indirectly on the basis of a movement-specific parameter (50) of the vehicle (80); - maintaining (104) the set actual pressure (40) for a first time period t1 (47) in order to heat the at least one brake disc (30); - reducing (106) the actual pressure (40) to a second target pressure (46) within a second time period t2 (48). [2] Method (100) according to one of the preceding claims, wherein the movement-specific parameter (50) comprises at least one of the following auxiliary variables: a negative acceleration of the vehicle (80), a wheel speed of at least one wheel of the vehicle (80). [3] Method (100) according to one of the preceding claims, wherein the set actual pressure (40) moves between a first minimum pressure Pmin, which enables the vehicle-specific parameter (50) to be determined, and a second maximum pressure Pmax, which does not yet produce a perceptible reaction of the vehicle (50) during the braking process. [4] Method (100) according to one of the preceding claims, wherein the first time period t1 (47) in which the actual pressure (40) is kept constant and / or a number of times the method is carried out within a defined time period t3 (49) depends on an environment-specific parameter (60) of the vehicle (80). [5] The method (100) of claim 4, wherein the environment-specific parameter (60) represents an outside temperature in an immediate environment of the vehicle (80). [6] Method (100) according to one of the preceding claims, wherein the setting of the actual pressure (40) is further carried out with a pressure sensor-based device (39). [7] Method (100) according to claim 6, wherein after the step of reducing (106) the set actual pressure (40), a step (108) of resetting the pressure sensor-based device (39) to an initial configuration (62) takes place, which corresponds to a state without pressurization of the at least one brake disc (30). [8] Method (100) according to one of the preceding claims, wherein the setting of the actual pressure (40) and the reduction of the set actual pressure (40) are carried out uniformly. [9] A computer program comprising machine-readable instructions which, when executed on one or more computers and / or compute instances, cause the computer or computers or compute instances to carry out the method according to any one of claims 1 to 8. [10] Machine-readable data carrier and / or download product with the computer program according to claim 9. [11] One or more computers and / or compute instances with the computer program according to claim 9, and / or with the machine-readable data carrier and / or download product according to claim 10.

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