Method for operating an electromechanical braking system and a vehicle equipped with an electromechanical braking system

Abstract

This prevents damage to the electromechanical braking system in the event of overheating, while simultaneously ensuring sufficient braking force. [Solution] A method for operating an electromechanical brake system for a vehicle having at least one electromechanical brake mounted on the front axle of the vehicle and at least one electromechanical brake mounted on the rear axle of the vehicle is to detect the temperature of the front brake and to control the front brake and the rear brake so that up to a specified temperature, the front brake can provide a first maximum front braking force and the rear brake can provide a first maximum rear braking force less than the first maximum front braking force, and if the temperature is higher than the specified temperature, the front brake can provide a second maximum front braking force and the rear brake can provide a second maximum rear braking force.

Description

Technical Field

[0001] The present disclosure relates to a method for operating an electromechanical brake system and a vehicle equipped with an electromechanical brake system.

Background Art

[0002] A vehicle's brake system is often exposed to strong loads that can be caused by repeated braking, such as during downhill driving or urban traffic, which can lead to overheating. Overheating of the brake system can result in a decrease in braking power (Bremsleistung) and damage to brake components. These problems occur in both conventional hydraulic brake systems and electromechanical brake systems, which are becoming increasingly important recently and enable individual wheel braking.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The problem of the present disclosure is to avoid damage to the electromechanical brake system during overheating and, at the same time, ensure sufficient braking power.

Means for Solving the Problems

[0004] In a first aspect of the present disclosure, the above problem is solved by a method for operating an electromechanical brake system of a vehicle having at least one electromechanical front axle brake assembled to a front axle of the vehicle and at least one electromechanical rear axle brake assembled to a rear axle of the vehicle, the method comprising: detecting the front axle brake temperature of at least one front axle brake; controlling at least one front axle brake and at least one rear axle brake, Up to a specified front axle brake temperature, at least one front axle brake can provide a first maximum front axle braking force, and at least one rear axle brake can provide a first maximum rear axle braking force that is less than the first maximum front axle braking force. After reaching a specified front axle brake temperature, at least one front axle brake is capable of providing a second maximum front axle braking force, and at least one rear axle brake is capable of providing a second maximum rear axle braking force. This includes controlling the second maximum front axle braking force to be less than the first maximum front axle braking force, and the second maximum rear axle braking force to be greater than the first maximum rear axle braking force.

[0005] In the method described herein, for reasons of driving stability, it is intended that, up to a specified front axle brake temperature, the first maximum front axle braking force that can be provided by at least one front axle brake is greater than the first maximum rear axle braking force that can be provided by at least one rear axle brake. Therefore, since at least one front axle brake is more heavily loaded than at least one rear axle brake, the front axle brake temperature is higher than the rear axle brake temperature up to a specified front axle brake temperature.

[0006] Front axle brake temperatures and rear axle brake temperatures can be detected, for example, by appropriate temperature sensors. Alternatively or additionally, front axle brake temperatures and rear axle brake temperatures can be detected by model-based monitoring that detects brake temperatures at specific time intervals based on the load applied to the brakes.

[0007] To prevent damage to at least one front axle brake due to overheating, when a specified front axle brake temperature is reached, the braking force (Bremskraft) is redistributed between at least one front axle brake and at least one rear axle brake by reducing the maximum braking force that can be provided by at least one front axle brake to a second maximum front axle brake force, and increasing the maximum rear axle brake force that can be provided by at least one rear axle brake to a second maximum rear axle brake force. This prevents damage to at least one front axle brake.

[0008] "At least one front axle brake" here refers to one or more brakes (front wheel brakes) mounted on the vehicle's front axle. These brakes can, for example, be assigned to each wheel and mounted on the vehicle's front axle, and may be configured to brake each wheel individually. Similarly, "at least one rear axle brake" refers to one or more brakes (rear wheel brakes) mounted on the vehicle's rear axle. These brakes can, for example, be assigned to each wheel and mounted on the vehicle's rear axle, and may be configured to brake each wheel individually.

[0009] At least one electromechanical front axle brake and at least one electromechanical rear axle brake may each have, for example, an electric motor and a rotary / translational transmission, the rotary / translational transmission being configured to convert the rotational motion of the electric motor shaft into translational motion to bring the brake pads of the corresponding brakes into physical contact with or away from the brake disc.

[0010] At least one electromechanical front axle brake and at least one electromechanical rear axle brake can be controlled, for example, by supplying power to an assigned electric motor. This also allows for variations in the maximum braking force that each brake can provide.

[0011] To ensure stable vehicle behavior even after reaching a specified front axle brake temperature, it is possible to further design the second maximum front axle braking force to be higher than the second maximum rear axle braking force.

[0012] If the brake system continues to be heavily loaded after reaching a specified front axle brake temperature, the rear axle brake temperature may also rise, which ultimately carries the risk of damage to at least one rear axle brake. To prevent damage to at least one rear axle brake, the method may further include deactivating at least one rear axle brake if a specified rear axle brake temperature is reached that is higher than the specified front axle brake temperature.

[0013] Furthermore, after deactivating at least one rear axle brake, it is possible to ensure that at least one front axle brake can continue to provide a second maximum front axle braking force. This specifically means that at least one front axle brake continues to operate, but this front axle brake provides only limited braking force. The driver can receive information about the reduction in braking force, thereby allowing the vehicle to come to a stop to allow the brake system to cool and thus restore full braking force. After the brake system has cooled, braking force can be made fully available again in both the front and rear axle brakes by switching the ignition on and off (Zuendungswechsel).

[0014] In summary, because it is more important from the standpoint of driving stability, the braking force of the rear axle is "sacrificed" according to the method of this disclosure in order to maintain the braking force of the front axle for as long as possible.

[0015] The above problems are solved in a second aspect of this disclosure by a vehicle equipped with an electromechanical braking system, the vehicle being At least one electromechanical front axle brake mounted on the vehicle's front axle, At least one electromechanical rear axle brake mounted on the rear axle of the vehicle, A control device configured to control at least one front axle brake and at least one rear axle brake, Up to a specified front axle brake temperature, at least one front axle brake can provide a first maximum front axle braking force, and at least one rear axle brake can provide a first maximum rear axle braking force that is less than the first maximum front axle braking force. After reaching a specified front axle brake temperature, at least one front axle brake is capable of providing a second maximum front axle braking force, and at least one rear axle brake is capable of providing a second maximum rear axle braking force. The system includes a control device that controls the second maximum front axle braking force to be less than the first maximum front axle braking force, and the second maximum rear axle braking force to be greater than the first maximum rear axle braking force.

[0016] With a vehicle designed in this way, it is possible to achieve the technical effects that can be attained in relation to the method described at the beginning.

[0017] From the perspective of stable driving behavior, it is possible that the second maximum front axle braking force is greater than the second maximum rear axle braking force.

[0018] The control device may be set to deactivate at least one rear axle brake when a specified rear axle brake temperature higher than a specified front axle brake temperature is reached. Further, it can be contemplated that after deactivating at least one rear axle brake, the second maximum front axle brake force can be continuously provided by at least one front axle brake.

[0019] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic diagram of a vehicle according to the present disclosure. [Figure 2] It is a chart showing the time profiles of the maximum front axle brake force and the maximum rear axle brake force in the method and vehicle according to the present disclosure. [Figure 3] It is a chart showing the time profiles of at least one front axle brake temperature and at least one rear axle brake temperature in the method and vehicle according to the present disclosure. [Figure 4] It is a flowchart of an exemplary method according to the present invention.

Embodiments for Carrying Out the Invention

[0021] FIG. 1 is a schematic view of a vehicle 100 according to the present disclosure. The vehicle 100 has a front axle 102 and a rear axle 104. The front axle 102 may have a left front wheel 102-1 at the left end of the front axle 102 and a right front wheel 102-2 at the right end of the front axle 102. The left front wheel 102-1 may be provided with a left electromechanical front axle brake 102-11 configured to brake the left front wheel 102-1. The right front wheel 102-2 may be provided with a right electromechanical front axle brake 102-22 configured to brake the right front wheel 102-2.

[0022] The rear axle 104 may have a left rear wheel 104-1 at the left end of the rear axle 104 and a right rear wheel 104-2 at the right end of the rear axle 104. The left rear wheel 104-1 may be provided with a left electromechanical rear axle brake 104-11 configured to brake the left rear wheel 104-1. The right rear wheel 104-2 may be provided with a right electromechanical rear axle brake 104-22 configured to brake the right rear wheel 104-2.

[0023] Relative terms such as "left", "right", "front", and "rear" used herein are related to the illustration in FIG. 1 and do not limit the present disclosure. These terms can represent, for example, the direction as seen by the driver during straight driving of the vehicle 100.

[0024] The front axle brakes 102-11, 102-22 and the rear axle brakes 104-11, 104-22 are components of an electromechanical brake system 105.

[0025] Vehicle 100 further includes a control device 106 configured to individually control the left front axle brake 102-11, the right front axle brake 102-22, the left rear axle brake 104-11, and the right rear axle brake 104-22. The control device 106 is data-exchange connected to each brake via their respective signal lines 106-1, 106-2, 106-3, and 106-4.

[0026] The front axle brakes 102-11 and 102-22 and the rear axle brakes 104-11 and 104-22 may each have an electric motor and a rotary / translational transmission, the rotary / translational transmission being configured to convert the rotational motion of the electric motor shaft into translational motion of each brake pad, and this translational motion is configured to either bring each brake pad into contact with the correspondingly arranged brake disc to achieve braking action, or to move it away from the brake disc to prevent braking action.

[0027] The control device 106 may be configured to adjust the maximum braking force available at the front axle 102 and rear axle 104 depending on the front axle brake temperature TV, i.e., the temperatures of the front axle brakes 102-11 and 102-22, and the rear axle brake temperature TH, i.e., the temperatures of the rear axle brakes 104-11 and 104-22. This will be described in detail below with reference to Figures 2 and 3.

[0028] Figure 2 is a schematic diagram showing the profile of the maximum front axle braking force FV, i.e., the maximum braking force that can be provided by the front axle brakes 102-11 and 102-22, and the profile of the maximum rear axle braking force FH, i.e., the maximum braking force that can be provided by the rear axle brakes 104-11 and 104-22, with respect to time t.

[0029] Figure 3 is a schematic diagram showing the temperature profile of the front axle brakes TV, i.e., the temperatures of the front axle brakes 102-11 and 102-22, and the temperature profile of the rear axle brakes TH, i.e., the temperatures of the rear axle brakes 104-11 and 104-22, with respect to time t.

[0030] The front axle brakes 102-11, 102-22 and the rear axle brakes 104-11, 104-22 are controlled by the control unit 106 based on the front axle brake temperature TV and the rear axle brake temperature TH. The front axle brake temperature TV and the rear axle brake temperature TH can be detected by temperature sensors assigned to and provided for each brake. Alternatively or additionally, the temperature can be detected by a model that provides brake temperature from brake behavior over past time intervals.

[0031] First, the front axle brake temperature TV, i.e., the temperature TV of the front axle brakes 102-11 and 102-22, is important. If this temperature is below the specified front axle brake temperature T1, it can be considered that the brake system 105 is not under excessive load. This condition exists in the time interval between time points t0 and t1 in Figures 2 and 3.

[0032] During this time interval, the front axle brakes 102-11 and 102-22 can provide a first maximum front axle braking force FV1, and the rear axle brakes 104-11 and 104-22 can provide a first maximum rear axle braking force FH1. The first maximum front axle braking force FV1 is greater than the first maximum rear axle braking force FH1, which is desirable for reasons of driving stability.

[0033] As shown in Figure 3, the front axle brake temperature TV reaches a first designated front axle brake temperature T1 at time t1, which suggests that the front axle brakes 102-11 and 102-22 are thermally overloaded. To avoid damage to the front axle brakes 102-11 and 102-22 due to this thermal overload, the control device 106 redistributes the maximum braking force between the front axle 102 and the rear axle 104 by reducing the maximum braking force FV available at the front axle 102 to a second maximum front axle brake force FV2 and increasing the maximum braking force FH available at the rear axle 104 to a second maximum rear axle brake force FH2. The change in the maximum braking force at the front axle 102 and the rear axle 104 occurs in the time between time t1 and time t1'. This region is not shown in Figure 3. In Figure 3, the change in maximum braking force occurs at time t1.

[0034] As shown in Figure 3, the redistribution of the maximum braking force by the control device 106 reduces the slope of the curve for the front axle brake temperature TV and increases the slope of the curve for the rear axle brake temperature TH. This reduces the load on the front axle brakes 102-11 and 102-22, thereby keeping them functional for a longer period, which is desirable in terms of stable driving behavior. As shown in Figure 2, even after time t1', the second maximum front axle braking force FV2 that can be provided by the front axle brakes 102-11 and 102-22 can be greater than the second maximum rear axle braking force FH2 that can be provided by the rear axle brakes 104-11 and 104-22, which is advantageous for stable driving behavior.

[0035] If the brake system 105 is heavily loaded after time t1 / t1', the temperatures of the front axle brakes 102-11 and 102-22 will continue to rise, but only slightly. Compared to the front axle brakes 102-11 and 102-22, the load on the rear axle brakes 104-11 and 104-22 will be greater from time t1 / t1', which may lead to the rear axle brake temperature TH exceeding the front axle brake temperature TV, as illustrated in Figure 3.

[0036] If the rear axle brake temperature TH reaches a specified rear axle brake temperature T2 which is higher than the specified front axle brake temperature T1, the control device 106 may deactivate the rear axle brakes 104-11 and 104-22 at time t2 to avoid damage to the rear axle brakes 104-11 and 104-22 due to overheating.

[0037] Upon deactivation of the rear axle brakes 104-11 and 104-22, the rear axle brake temperature TH decreases from time t2, as shown in Figure 3. As shown in Figure 2, the rear axle braking force available from time t2 also decreases accordingly. The driver of vehicle 100 can receive information regarding the deactivation of the rear axle brakes 104-11 and 104-22 so that the driving behavior can be appropriately adapted.

[0038] To ensure that the vehicle can be reliably braked until it comes to a stop and the brake system 105 has cooled down, the front axle brakes 102-11 and 102-22 can be operated to continue providing a second maximum front axle braking force FV2 even after the rear axle brakes 104-11 and 104-22 have stopped working, thereby providing braking force.

[0039] However, for safety reasons, the vehicle 100 must be stopped after the rear axle brakes 104-11 and 104-22 have deactivated in order to allow the brake system 105 to cool and thereby become functional again. As shown in Figure 3, this is done at time t3, in which case the front axle brake temperature TV also decreases from this point onward. After the brake system 205 has cooled, the braking force can be made fully available again by turning the ignition on and off.

[0040] Figure 4 shows a flowchart of an exemplary method 200 for operating the electromechanical brake system 105, and method 200 is, Detecting the front axle brake temperature TV of front axle brakes 102-11 and 102-22, Controlling the front axle brakes 102-11, 102-22 and the rear axle brakes 104-11, 104-22, 220 Up to a specified front axle brake temperature T1, the front axle brakes 102-11 and 102-22 can provide a first maximum front axle braking force FV1, and the rear axle brakes 104-11 and 104-22 can provide a first maximum rear axle braking force FH1 that is smaller than the first maximum front axle braking force FV1. After reaching the specified front axle brake temperature T1, the front axle brakes 102-11 and 102-22 can provide a second maximum front axle braking force FV2, and the rear axle brakes 104-11 and 104-22 can provide a second maximum rear axle braking force FH2. This includes controlling the second maximum front axle braking force FV2 to be less than the first maximum front axle braking force FV1, and the second maximum rear axle braking force FH2 to be greater than the first maximum rear axle braking force FH1. [Explanation of Symbols]

[0041] 100 vehicles 102 Front Axle 102-1 Left front wheel 102-2 Right front wheel 102-11 Left electromechanical front axle brake 102-22 Right electromechanical front axle brake 104 Rear Axle 104-1 Left rear wheel 104-2 Right rear wheel 104-11 Left electromechanical rear axle brake 104-22 Right electromechanical rear axle brake 105 Electromechanical Brake System 106 Control device 106-1, 106-2, 106-3, 106-4 signal lines 200 ways FH1 First Maximum Rear Axle Brake Force FH2 Second Maximum Rear Axle Brake Force FV1 First Maximum Front Axle Brake Force FV2 Second Maximum Front Axle Braking Force T1 Front Axle Brake Temperature T2 Rear Axle Brake Temperature

Claims

1. A method (200) for operating an electromechanical braking system (105) of a vehicle (100), wherein the vehicle (100) has at least one electromechanical front axle brake (102-11, 102-22) mounted on the front axle (102) of the vehicle (100) and at least one electromechanical rear axle brake (104-11, 104-22) mounted on the rear axle (104) of the vehicle (100), and the method (200) is, Detecting the front axle brake temperature (TV) of at least one of the front axle brakes (102-11, 102-22) (210), Controlling the at least one front axle brake (102-11, 102-22) and the at least one rear axle brake (104-11, 104-22) (220), Up to a specified front axle brake temperature (T1), the at least one front axle brake (102-11, 102-22) is capable of providing a first maximum front axle braking force (FV1), and the at least one rear axle brake (104-11, 104-22) is capable of providing a first maximum rear axle braking force (FH1) that is smaller than the first maximum front axle braking force (FV1). After reaching the specified front axle brake temperature (T1), the at least one front axle brake (102-11, 102-22) is capable of providing a second maximum front axle braking force (FV2), and the at least one rear axle brake (104-11, 104-22) is capable of providing a second maximum rear axle braking force (FH2). A method comprising controlling the second maximum front axle braking force (FV2) to be less than the first maximum front axle braking force (FV1) and the second maximum rear axle braking force (FH2) to be greater than the first maximum rear axle braking force (FH1).

2. The method according to claim 1 (200), wherein the second maximum front axle braking force (FV2) is greater than the second maximum rear axle braking force (FH2).

3. The method according to claim 1 or 2 (200), further comprising deactivating at least one of the rear axle brakes (104-11, 104-22) when a specified rear axle brake temperature (T2) is reached that is higher than the specified front axle brake temperature (T1).

4. The method according to claim 3 (200), wherein, after deactivating the at least one rear axle brake (104-11, 104-22), the at least one front axle brake (102-11, 102-22) can continue to provide the second maximum front axle braking force (FV2).

5. A vehicle (200) equipped with an electromechanical braking system (105), wherein the vehicle is At least one electromechanical front axle brake (102-11, 102-22) is mounted on the front axle (102) of the vehicle (100), At least one electromechanical rear axle brake (104-11, 104-22) is mounted on the rear axle (104) of the vehicle (100), A control device (106) configured to control the at least one front axle brake (102-11, 102-22) and the at least one rear axle brake (104-11, 104-22), Up to a specified front axle brake temperature (T1), the at least one front axle brake (102-11, 102-22) is capable of providing a first maximum front axle braking force (FV1), and the at least one rear axle brake (104-11, 104-22) is capable of providing a first maximum rear axle braking force (FH1) that is smaller than the first maximum front axle braking force (FV1). After reaching the specified front axle brake temperature (T1), the at least one front axle brake (102-11, 102-22) is capable of providing a second maximum front axle braking force (FV2), and the at least one rear axle brake (104-11, 104-22) is capable of providing a second maximum rear axle braking force (FH2). A vehicle having a control device configured to control the second maximum front axle braking force (FV2) to be less than the first maximum front axle braking force (FV1), and the second maximum rear axle braking force (FH2) to be greater than the first maximum rear axle braking force (FH1).

6. The vehicle (200) according to claim 5, wherein the second maximum front axle braking force (FV2) is greater than the second maximum rear axle braking force (FH2).

7. The vehicle (200) according to claim 5 or 6, wherein the control device (106) is configured to deactivate at least one of the rear axle brakes (104-11, 104-22) when it reaches a specified rear axle brake temperature (T2) that is higher than the specified front axle brake temperature (T1).

8. The vehicle (200) according to claim 7, wherein after the deactivation of the at least one rear axle brake (104-11, 104-22), the at least one front axle brake (102-11, 102-22) can continue to provide the second maximum front axle braking force (FV2).

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