A decoupled braking system with a brake thermal fade alarm function

Abstract

The present invention discloses a decoupled braking system with a brake thermal fade alarm function, which consists of a decoupled brake, a brake controller, and a wheel angular velocity sensor. When the vehicle brakes, the brake controller reads information such as the angular velocity of the wheel and the braking force output by the brake, and real-time monitors whether the wheel brake of the vehicle has thermal fade. When it is found that the temperature of the wheel brake is too high and the performance of the brake fades, it can promptly alarm the driver, thereby avoiding traffic accidents caused by the driver's ignorance of the thermal fade of the braking system.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive braking systems, and particularly to a decoupled braking system with a brake thermal fade alarm function. Background Art

[0002] With the progress of technology, more and more vehicles use decoupled electro-hydraulic brakes (EHB) or electro-mechanical brakes (EMB). These two types of brakes can use electrical signals to control the braking force. With control programs, the flexibility of braking control can be greatly improved, and they are also very convenient to be used in autonomous driving. At the same time, in order to improve driving quality, some decoupled brakes also use deceleration closed-loop control. That is to say, whether the vehicle is empty or loaded, when the force applied by the driver on the brake pedal is constant, the brake automatically controls the magnitude of the braking force so that the deceleration of the empty vehicle and the loaded vehicle is the same.

[0003] When a vehicle brakes, it usually uses friction to convert the kinetic energy of the vehicle into heat energy and dissipate it. When using wheel brakes for braking, due to the limited heat dissipation capacity of the wheel brakes, part of the generated heat energy is dissipated into the air, and the other part heats the wheel brakes, causing the temperature of the wheel brakes to rise. After the temperature rises, it will also cause the energy efficiency ratio (friction coefficient) of the wheel brakes to decrease, which is called the thermal fade of the brakes.

[0004] When the brakes experience thermal fade, the performance of the brakes deteriorates. When the brakes output the same braking hydraulic pressure or braking force, the deceleration of the vehicle is smaller than usual. That is to say, when pressing the brake pedal with the same force, the deceleration of the vehicle becomes smaller than before. Therefore, experienced drivers can judge whether there is brake thermal fade by judging the force on the brake pedal and the deceleration of the vehicle. However, for a decoupled braking system with deceleration closed-loop control, since the control program can automatically adjust the braking force of the brakes, when the brakes experience thermal fade, the braking system automatically increases the braking force. When the force on the brake pedal remains unchanged, the deceleration of the vehicle also remains unchanged. Therefore, the driver cannot judge whether there is thermal fade by judging the relationship between the force on the brake pedal and the deceleration of the vehicle. And when the temperature of the brakes is too high and serious thermal fade occurs, the increased braking force of the brakes at this time will not be able to compensate for the decline in braking performance caused by thermal fade. At this time, there may be major traffic accidents due to insufficient braking performance of the vehicle.

[0005] For some ordinary drivers, they may not have the ability to judge whether there is brake thermal fade by judging the force on the brake pedal and the deceleration of the vehicle, and are more likely to have major traffic accidents due to brake thermal fade. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention aims to provide a decoupled braking system with a brake thermal fade alarm function.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] As a technical solution of the present invention, a decoupled braking system with a brake thermal fade alarm function includes an electro-hydraulic brake EHB, a wheel angular velocity sensor, a brake controller ECU, and a brake cylinder; the wheel angular velocity sensor is used to measure the angular velocity of the wheel; the electro-hydraulic brake EHB is connected to the brake cylinder through a brake pipeline and brakes the wheel through the brake cylinder; the brake controller ECU is communicatively connected to the electro-hydraulic brake EHB and the wheel angular velocity sensor respectively;

[0009] The brake controller ECU is used to, during a driving process from vehicle start to stop, when the driver steps on the brake each time, record the output hydraulic pressure x of the EHB and the angular velocity y of the wheel measured by the wheel angular velocity sensor in real time, then calculate the angular deceleration y' of the wheel and the ratio y' / x between the angular deceleration of the wheel and the output hydraulic pressure of the EHB, and update and record the maximum value w in the ratio y' / x calculated during this driving process. Thereafter, calculate the ratio between the ratio y' / x of the current angular deceleration of the wheel and the output hydraulic pressure of the EHB and the maximum value w of the ratio in the record; the brake controller ECU is further used to, when the ratio between the ratio y' / x of the current angular deceleration of the wheel and the output hydraulic pressure of the EHB and the maximum value w of the ratio in the record is less than a set threshold, determine that the electro-hydraulic brake has thermal fade and send a brake overheat alarm to the driver.

[0010] Further, in the above system, the brake controller ECU is also used to clear the maximum value of the ratio in the record when the vehicle stops.

[0011] As another technical solution of the present invention, a decoupled braking system with a brake thermal fade alarm function includes an electro-mechanical brake EMB, a wheel angular velocity sensor, and a brake controller ECU; the wheel angular velocity sensor is used to measure the angular velocity of the wheel; the electro-mechanical brake EMB is used to brake the wheel; the brake controller ECU is communicatively connected to the electro-mechanical brake EMB and the wheel angular velocity sensor respectively;

[0012] The brake controller ECU is used to, during a driving process of the vehicle from start to stop, every time the driver steps on the brake, record in real time the output force x' of the EMB and the angular velocity y of the wheel measured by the wheel angular velocity sensor, then calculate the angular deceleration y' of the wheel and the ratio y' / x' between the angular deceleration of the wheel and the output force of the EMB, and update and record the maximum value w' of the ratio y' / x' calculated during this driving process. Thereafter, calculate the ratio between the current ratio y' / x' of the angular deceleration of the wheel and the output force of the EMB and the maximum value w' of the ratio in the record; the brake controller ECU is further used to, when the ratio between the current ratio of the angular deceleration of the wheel and the output force of the EMB and the maximum value w' of the ratio in the record is less than a set threshold, determine that the electro-mechanical brake has thermal fade and send an overheat alarm to the driver.

[0013] Further, in the above system, the brake controller ECU is further used to clear the maximum value of the ratio in the record when the vehicle stops.

[0014] The beneficial effects of the present invention are as follows: By calculating the angular deceleration of the wheel and the output hydraulic pressure / output force of the brake to determine whether the brake has thermal fade, the present invention can effectively improve the driving safety of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the system according to Embodiment 1 of the present invention;

[0016] Figure 2 is a schematic structural diagram of the system according to Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The following will further describe the present invention in conjunction with the drawings. It should be noted that this embodiment is based on the present technical solution and gives detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to this embodiment.

[0018] Embodiment 1

[0019] This embodiment provides a decoupled braking system with a brake thermal fade alarm function, which is applicable to vehicles using electro-hydraulic brakes EHB, such as Figure 1As shown in the figure, it includes an electro-hydraulic brake EHB 101, a wheel angular velocity sensor 102, a brake controller ECU 100, and a brake wheel cylinder 103. The wheel angular velocity sensor 102 is used to measure the angular velocity of the wheel 105. The electro-hydraulic brake EHB 101 is connected to the brake wheel cylinder 103 through a brake pipeline 104 and brakes the wheel 105 through the brake wheel cylinder 103. The brake controller ECU 100 is communicatively connected to the electro-hydraulic brake EHB 101 and the wheel angular velocity sensor 102 respectively. Specifically, each wheel angular velocity sensor 102 is connected to the vehicle harness 107 through a data line 106, thereby connecting to the brake controller ECU 100.

[0020] The brake controller ECU is used to record the output hydraulic pressure x of the EHB and the angular velocity y of the wheel measured by the wheel angular velocity sensor in real time every time the driver steps on the brake during a driving process of the vehicle (i.e., a continuous process from vehicle start to stop), and then calculates the angular deceleration y' of the wheel and the ratio y' / x between the angular deceleration of the wheel and the output hydraulic pressure of the EHB, and updates and records the maximum value w of the ratio y' / x calculated during this driving process. Subsequently, it calculates the ratio between the current ratio y' / x of the angular deceleration of the wheel and the output hydraulic pressure of the EHB and the maximum value w of the ratio in the record. The brake controller ECU is also used to determine that the electro-hydraulic brake has thermal fade and send a brake overheat alarm to the driver in a way such as sound or light when the ratio between the current ratio y' / x of the angular deceleration of the wheel and the output hydraulic pressure of the EHB and the maximum value w of the ratio in the record is less than a set threshold.

[0021] Furthermore, in this embodiment, the brake controller ECU is also used to clear the maximum value of the ratio in the record when the vehicle stops (at this time, the vehicle may be loading or unloading goods or taking on or off passengers, and the weight of the vehicle may change).

[0022] It should be noted that the ratio of the angular deceleration to the output hydraulic pressure of the EHB is proportional to the friction coefficient of the brake. The friction coefficient of the brake is related to temperature. Some friction coefficients decrease with the increase of temperature, and some friction coefficients increase with the increase of temperature, but after exceeding a certain temperature, the friction coefficient decreases with the increase of temperature. Therefore, during each braking process of the driver, the ECU needs to calculate the ratio of the angular deceleration of the wheel to the output hydraulic pressure of the EHB in real time, record the maximum value of the ratio, and determine whether the brake has thermal fade by calculating the ratio between the current ratio of the angular deceleration of the wheel to the output hydraulic pressure of the EHB and the maximum value of the ratio in the record and judging its relationship with the preset threshold.

[0023] Embodiment 2

[0024] This embodiment provides a decoupled braking system with a brake thermal fade alarm function, which is applicable to vehicles using electro-mechanical brakes (EMBs), such as Figure 2 As shown, it includes an electro-mechanical brake (EMB) 201, a wheel angular velocity sensor 202, and a brake controller ECU 200. The wheel angular velocity sensor 202 is used to measure the angular velocity of the wheel 203; the electro-mechanical brake EMB 201 is used to brake the wheel 203; the brake controller ECU 200 is communicatively connected to the electro-mechanical brake EMB 201 and the wheel angular velocity sensor 202 respectively. Among them, each electro-mechanical brake EMB 201 is connected to the brake controller ECU 200 through a control signal line 204, and each wheel angular velocity sensor 202 is connected to the vehicle harness 206 through a data line 205 to be connected to the brake controller ECU 200.

[0025] For vehicles using EMBs, it is possible to determine whether the brake has experienced thermal fade by calculating the ratio of the angular deceleration of the wheel to the output force of the EMB. Therefore, in this embodiment, the brake controller ECU is configured to, during a driving process of the vehicle (i.e., a continuous process from vehicle startup to stop), each time the driver steps on the brake, record the output force x' of the EMB and the angular velocity y of the wheel measured by the wheel angular velocity sensor in real time, and then calculate the angular deceleration y' of the wheel and the ratio y' / x' between the angular deceleration of the wheel and the output force of the EMB, and update and record the maximum value w' of the calculated ratio y' / x' during this driving process. Subsequently, calculate the ratio between the current ratio y' / x' of the angular deceleration of the wheel to the output force of the EMB and the maximum value w' of the ratio in the record; the brake controller ECU is also configured to determine that the electro-mechanical brake has experienced thermal fade when the ratio between the current ratio of the angular deceleration of the wheel to the output force of the EMB and the maximum value w' of the ratio in the record is less than a set threshold, and send a brake overheat alarm to the driver by means of sound or light, etc.

[0026] Furthermore, in this embodiment, the brake controller ECU is also configured to clear the maximum value of the ratio in the record when the vehicle stops (at this time, the vehicle may be loading or unloading goods or taking on or off passengers, and the weight of the vehicle may change).

[0027] For those skilled in the art, various corresponding changes and deformations can be given according to the above technical solutions and concepts, and all such changes and deformations should be included within the protection scope of the claims of the present invention.

Claims

1. A decoupled braking system with a brake thermal fade alarm function, characterized in that, It includes an electro-hydraulic brake EHB, a wheel angular velocity sensor, a brake controller ECU, and a brake cylinder; the wheel angular velocity sensor is used to measure the angular velocity of the wheel; the electro-hydraulic brake EHB is connected to the brake cylinder through a brake pipeline and brakes the wheel through the brake cylinder; the brake controller ECU is communicatively connected to the electro-hydraulic brake EHB and the wheel angular velocity sensor respectively; The brake controller ECU is used to, during a driving process from vehicle start to stop, when the driver steps on the brake each time, record the output hydraulic pressure x of the EHB and the angular velocity y of the wheel measured by the wheel angular velocity sensor in real time, then calculate the angular deceleration y' of the wheel and the ratio y' / x between the angular deceleration of the wheel and the output hydraulic pressure of the EHB, and update and record the maximum value w of the ratio y' / x calculated during this driving process. Thereafter, calculate the ratio between the ratio y' / x of the current angular deceleration of the wheel and the output hydraulic pressure of the EHB and the maximum value w of the ratio in the record; the brake controller ECU is further used to, when the ratio between the ratio y' / x of the current angular deceleration of the wheel and the output hydraulic pressure of the EHB and the maximum value w of the ratio in the record is less than a set threshold, determine that the electro-hydraulic brake has thermal fade and send a brake overheat alarm to the driver.

2. The decoupled braking system with a brake thermal fade alarm function according to claim 1, characterized in that, The brake controller ECU is further used to clear the maximum value of the ratio in the record when the vehicle stops.

3. A decoupled braking system with a brake thermal fade alarm function, characterized in that, It includes an electro-mechanical brake EMB, a wheel angular velocity sensor, and a brake controller ECU; the wheel angular velocity sensor is used to measure the angular velocity of the wheel; the electro-mechanical brake EMB is used to brake the wheel; the brake controller ECU is communicatively connected to the electro-mechanical brake EMB and the wheel angular velocity sensor respectively; The brake controller ECU is used to, during a driving process from vehicle start to stop, when the driver steps on the brake each time, record the output force x' of the EMB and the angular velocity y of the wheel measured by the wheel angular velocity sensor in real time, then calculate the angular deceleration y' of the wheel and the ratio y' / x' between the angular deceleration of the wheel and the output force of the EMB, and update and record the maximum value w' of the ratio y' / x' calculated during this driving process. Thereafter, calculate the ratio between the ratio y' / x' of the current angular deceleration of the wheel and the output force of the EMB and the maximum value w' of the ratio in the record; the brake controller ECU is further used to, when the ratio between the ratio y' / x' of the current angular deceleration of the wheel and the output force of the EMB and the maximum value w' of the ratio in the record is less than a set threshold, determine that the electro-mechanical brake has thermal fade and send a brake overheat alarm to the driver.

4. The decoupled braking system with a brake thermal fade alarm function according to claim 3, characterized in that, The brake controller ECU is further used to clear the maximum value of the ratio in the record when the vehicle stops.

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