Vehicle control method, brake system, and vehicle

Abstract

The application discloses a vehicle control method, a brake system and a vehicle. The vehicle control method comprises the following steps: detecting an auxiliary brake handle closing signal; determining that a vehicle enters a target brake torque mode; acquiring a current driving motor actual brake torque and a requested retarder target brake torque; and acquiring a sum of the current driving motor actual brake torque and the requested retarder target brake torque. The method further comprises the following steps: determining that a running time of the target brake torque mode is less than or equal to a first preset time; determining a whole vehicle brake demand torque according to the requested retarder target brake torque and the sum of the current driving motor actual brake torque and the requested retarder target brake torque; determining that the running time of the target brake torque mode is greater than the first preset time; and taking the requested retarder target brake torque as the whole vehicle brake demand torque. The method can solve the problem of vehicle braking at the initial stage of the target brake torque mode, and improve driving stability and safety.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a vehicle control method, braking system, and vehicle. Background Technology

[0002] More and more new energy commercial vehicles in China are equipped with EBS (Electronic Braking System), and currently, the control software for EBS systems is basically derived from that of traditional commercial vehicles. Traditional commercial vehicles are mostly equipped with hydraulic retarders. The working principle of the EBS system is that the driving intervention is on the engine, while the braking intervention is on the hydraulic retarder.

[0003] In existing technologies, new energy commercial vehicles are usually not equipped with hydraulic retarders, and when the vehicle brakes, in the initial stage of entering the target braking torque mode, the vehicle often experiences jerking, which affects driving stability and safety. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first objective of the present invention is to propose a vehicle control method that can solve the problem of vehicle jerking when the vehicle enters the initial stage of the target braking torque mode, thereby improving the driving stability and safety of the vehicle.

[0005] The second objective of this invention is to provide a braking system.

[0006] The third objective of this invention is to provide a vehicle.

[0007] To achieve the above objectives, a vehicle control method is proposed in a first aspect of the present invention. The vehicle includes a drive motor. The vehicle control method includes: detecting an auxiliary brake lever closing signal; determining that the vehicle has entered a target braking torque mode; acquiring the current actual braking torque of the drive motor and the requested target braking torque of the retarder; acquiring the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder; determining that the running time of the target braking torque mode is less than or equal to a first preset time; determining the vehicle's braking demand torque based on the requested target braking torque of the retarder and the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder; and determining that the running time of the target braking torque mode is greater than the first preset time, using the requested target braking torque of the retarder as the vehicle's braking demand torque.

[0008] According to the vehicle control method proposed in this embodiment of the invention, when the vehicle is in braking state, the function of the drive motor is replaced by the hydraulic retarder. In the initial stage of the vehicle entering the target braking torque mode, the actual braking torque of the current drive motor is obtained as the sum of the engine friction torque and the requested target braking torque of the retarder, and locked. Based on the running time of the target braking torque mode and the requested target braking torque of the retarder, it is determined whether the vehicle's braking torque requirement follows the requested target braking torque of the retarder or the locked torque is used. This can solve the problem of vehicle jerking in the initial stage of the EBS system entering the target braking torque mode intervention caused by the large difference in the period of the CAN message containing the engine friction torque signal and the retarder torque signal, which leads to torque asynchrony. This ensures that the braking torque output of the drive motor always meets the vehicle's torque requirement, improving the driving stability and safety of the vehicle.

[0009] In some embodiments of the present invention, determining that the operating time of the target braking torque mode is less than or equal to the first preset time, and determining the vehicle braking demand torque based on the requested retarder target braking torque and the sum of the current drive motor actual braking torque and the requested retarder target braking torque, includes: determining that the operating time of the target braking torque mode is less than or equal to the first preset time, determining that the requested retarder target braking torque is greater than the sum of the current drive motor actual braking torque and the requested retarder target braking torque, and controlling the vehicle braking demand torque to follow the requested retarder target braking torque; or, determining that the operating time of the target braking torque mode is less than or equal to the first preset time, determining that the requested retarder target braking torque is less than or equal to the sum of the current drive motor actual braking torque and the requested retarder target braking torque, and using the sum of the current drive motor actual braking torque and the requested retarder target braking torque as the vehicle braking demand torque.

[0010] In some embodiments of the present invention, after determining that the vehicle has entered the target braking torque mode and obtaining the actual braking torque of the current drive motor, the vehicle control method further includes: controlling the operating state of the drive motor according to the vehicle braking torque requirement, and receiving the braking torque signal fed back by the drive motor; putting the braking torque signal into the retarder message, and clearing the actual braking torque of the current drive motor.

[0011] In some embodiments of the present invention, the vehicle control method further includes: determining the driving intervention mode and braking intervention mode of the vehicle; and determining the target requested torque of the vehicle based on the driving intervention mode and the braking intervention mode.

[0012] In some embodiments of the present invention, determining the target requested torque of the vehicle based on the driving intervention mode and the braking intervention mode includes: determining that the driving intervention mode is a target driving torque mode and the braking intervention mode is a no-request or braking torque limiting mode, and controlling the target requested torque of the vehicle to follow the target driving torque mode; or, determining that the braking intervention mode is the target braking torque mode and the driving intervention mode is a no-request or driving torque limiting mode, and controlling the target requested torque of the vehicle to follow the target braking torque mode; or, determining that the driving intervention mode is the driving torque limiting mode and the braking intervention mode is a no-request, and controlling the target requested torque of the vehicle to be less than or equal to the driving torque limiting value.

[0013] In some embodiments of the present invention, determining the target requested torque of the vehicle based on the driving intervention mode and the braking intervention mode further includes: determining that the driving intervention mode is the driving torque limiting mode and the braking intervention mode is the braking torque limiting mode, and obtaining the vehicle torque requirement; and determining the target requested torque of the vehicle based on the driving torque limiting value, the braking torque limiting value and the vehicle torque requirement.

[0014] In some embodiments of the present invention, determining the target requested torque of the vehicle based on the drive torque limit value, the braking torque limit value, and the vehicle torque requirement includes: if the vehicle torque requirement is greater than zero, then 0 ≤ the target requested torque of the vehicle ≤ the drive torque limit value; or, if the vehicle torque requirement is less than zero, then the braking torque limit value ≤ the target requested torque of the vehicle ≤ 0.

[0015] To achieve the above objectives, a second aspect of the present invention provides a braking system, comprising: a brake pedal; an auxiliary brake lever, wherein the auxiliary brake lever, when in the OFF position, is used to provide an auxiliary brake lever closing signal; a drive motor, used to provide driving force and braking force to the vehicle; and a controller connected to the brake pedal, the auxiliary brake lever and the drive motor, used to perform control according to any of the vehicle control methods described above.

[0016] According to the braking system proposed in the embodiments of the present invention, the controller is connected to the auxiliary brake handle, the brake pedal and the drive motor respectively. By adopting the vehicle control method described in the following embodiments, the problem of vehicle jerking caused by torque asynchrony due to the large difference in the period of the CAN message containing the engine friction torque signal and the retarder torque signal can be solved. This ensures that the braking torque output of the drive motor always meets the torque requirements of the whole vehicle, thereby improving the driving stability and safety of the vehicle.

[0017] To achieve the above objectives, embodiments of the present invention also provide a vehicle, including a vehicle body and the braking system described above, wherein the braking system is disposed on the vehicle body.

[0018] According to the vehicle proposed in the embodiments of the present invention, by employing the braking system of the above embodiment, the problem of vehicle jerking caused by the large difference in the period of the CAN messages containing the engine friction torque signal and the retarder torque signal during the initial stage of the EBS system's intervention in the target braking torque mode during braking can be solved. This results in torque asynchrony. The braking torque output of the entire vehicle always meets the vehicle's torque requirements, improving the vehicle's driving stability and safety.

[0019] In some embodiments of the present invention, the vehicle is a new energy commercial vehicle.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0022] Figure 1 A block diagram of a vehicle according to an embodiment of the present invention;

[0023] Figure 2 This is a block diagram of a braking system according to an embodiment of the present invention;

[0024] Figure 3 A flowchart of a vehicle control method according to an embodiment of the present invention;

[0025] Figure 4 A flowchart of a vehicle control method according to another embodiment of the present invention;

[0026] Figure 5 This is a flowchart of a vehicle control method according to yet another embodiment of the present invention.

[0027] Figure label:

[0028] 10 vehicles;

[0029] Vehicle body 1, braking system 2;

[0030] Brake pedal 21, auxiliary brake handle 22, drive motor 23, controller 24. Detailed Implementation

[0031] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0032] More and more new energy commercial vehicles in China are equipped with EBS systems, but currently, the control software for these systems is primarily derived from that of traditional commercial vehicles. Traditional commercial vehicles are mostly equipped with hydraulic retarders; therefore, the EBS system's operating mechanism involves the engine as the driving intervention target and the hydraulic retarder as the braking intervention target. However, new energy commercial vehicles typically do not have hydraulic retarders. Since the drive motors in new energy vehicles have electric braking capabilities, the drive motors can essentially replace the function of the hydraulic retarder. Therefore, the drive motor is the target of both driving and braking interventions in the EBS system. The hydraulic retarder can be manually controlled via a multi-position auxiliary brake lever, or it can be controlled by the EBS system when the multi-position auxiliary brake lever is closed.

[0033] In related technologies, for new energy commercial vehicles without hydraulic retarders, when the auxiliary brake lever is closed, the EBS system intervenes during driving or braking. After the EBS system enters the target braking torque mode, the CAN message periods for the engine friction torque signal and the retarder torque signal differ significantly, resulting in torque asynchrony and causing a jerking problem in the initial stage of entering the target braking torque mode. Based on this, this invention proposes a vehicle control method. This method effectively solves the jerking problem during the initial stage of the EBS system entering the target braking torque mode, improving vehicle driving stability and safety.

[0034] To facilitate the explanation of the technical solution, the vehicle and braking system of the present invention will be described first below.

[0035] Figure 1 This is a block diagram of a vehicle according to an embodiment of the present invention, such as... Figure 1 As shown, vehicle 10 includes vehicle body 1 and braking system 2.

[0036] The braking system 2 is installed on the vehicle body 1. The braking system 2 is a series of specialized devices that can forcibly reduce the speed of the vehicle. The braking system mainly consists of four parts: a power supply device, a control device, a transmission device, and brakes. The main functions of the braking system are to slow down or even stop a moving vehicle, maintain a stable speed for a vehicle traveling downhill, and keep a stopped vehicle stationary.

[0037] In some embodiments of the present invention, vehicle 10 may be a new energy commercial vehicle, which is a pure electric vehicle, and the energy required by the whole vehicle is provided entirely by the drive motor.

[0038] Figure 2This is a block diagram of a braking system according to an embodiment of the present invention, wherein the braking system 2 includes a brake pedal 21, an auxiliary brake handle 22, a drive motor 23, and a controller 24.

[0039] In some embodiments, controller 24 may be a main control unit for executing vehicle control methods. The controller may include a vehicle controller, domain controller, or other similar electronic control unit. Controller 24 is connected to the auxiliary brake lever 22, brake pedal 21, and drive motor 23 respectively, and is used to control the vehicle according to the vehicle control method described in the following embodiments to achieve intelligent management of the vehicle braking system 2 and ensure the performance of vehicle 10 in different operating modes.

[0040] For vehicles equipped with hydraulic retarders, when the brake pedal 21 is depressed, the hydraulic retarder can be manually controlled via the multi-position auxiliary brake lever, or it can be controlled by the EBS system when the multi-position auxiliary brake lever is closed. However, since this new energy commercial vehicle is not equipped with a hydraulic retarder, the drive motor 23 of this new energy vehicle has an electric braking function that replaces the function of the hydraulic retarder. Therefore, the drive motor is the object of both the EBS system's drive intervention and the braking intervention object. Thus, in this embodiment, after the driver depresses the brake pedal 21, the braking system 2 enters the braking mode, and when the multi-position auxiliary brake lever 22 is closed, it is actually the drive motor 23 that is controlled by the EBS system.

[0041] According to the braking system 2 proposed in the embodiment of the present invention, the controller 24 is connected to the auxiliary brake handle 22, the brake pedal 21 and the drive motor 23 respectively. By adopting the vehicle control method described in the following embodiment, the problem of vehicle jerking caused by torque asynchrony due to the large difference in the period of the CAN message where the engine friction torque signal and the retarder torque signal are located can be solved. This ensures that the braking torque output of the drive motor 23 always meets the torque requirements of the whole vehicle, thereby improving the driving stability and safety of the vehicle.

[0042] In some embodiments, such as Figure 1 The diagram shows a flowchart of a vehicle control method according to an embodiment of the present invention, wherein the vehicle includes a drive motor, and the vehicle control method includes at least steps S1-S3, as follows:

[0043] S1, detect the auxiliary brake handle closing signal, determine that the vehicle has entered the target braking torque mode, obtain the current actual braking torque of the drive motor and the requested target braking torque of the retarder, and obtain the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder.

[0044] It is understood that the auxiliary brake lever can be used to control the hydraulic retarder, which can be manually controlled or controlled by the EBS system. In this embodiment of the invention, the braking system does not have a hydraulic retarder; instead, the electric braking function of the drive motor replaces the function of the hydraulic retarder. The auxiliary brake lever can select multiple positions during operation, such as positions 1-5, each requiring different braking strengths. For new energy commercial vehicles, the braking force during braking comes entirely from the drive motor, achieved through electric braking via the drive motor's reverse drag. For example, among positions 1-5, the braking strength is minimum when the auxiliary brake lever is in position 1, and the reverse drag force provided by the drive motor is also minimum during braking; conversely, the braking strength is maximum when the auxiliary brake lever is in position 5, and the reverse drag force provided by the drive motor is also maximum during braking. During braking, the vehicle controller first acquires the position signal of the auxiliary brake lever. The position signal is different for each position, and the vehicle controller can control the reverse drag force output by the drive motor based on the acquired position signal.

[0045] Furthermore, when the auxiliary brake lever is deactivated, for example, in the OFF position, and the driver depresses the brake pedal, the EBS system will not adjust the auxiliary brake lever position. It will only detect whether the auxiliary brake lever is engaged in the appropriate position. If it is detected that the auxiliary brake lever is engaged, the EBS system will not intervene, and the vehicle will use air braking. If it detects that the auxiliary brake lever is not engaged in the appropriate position, such as in the OFF position, the EBS system will take over, and the intervention method will be electric braking.

[0046] For new energy commercial vehicles, only one drive motor can generate electric braking. With the auxiliary brake lever closed, before the target braking torque mode of the EBS system intervenes, the vehicle's coasting electric braking torque or braking electric braking torque must be treated as engine friction torque. In other words, the engine friction torque is the actual braking torque of the current drive motor. During braking, before the EBS system intervenes, the actual braking torque of the current drive motor is included in the engine friction torque, not in the retarder message.

[0047] Understandably, the EBS system identifies two types of braking mechanisms on the vehicle: engine braking and hydraulic retarder braking. During braking, if the braking torque from the drive motor is input into the hydraulic retarder's communication, the EBS system interprets this as the hydraulic retarder engaging, assuming human intervention with the auxiliary brake lever. In this case, the EBS system assumes the user is taking over the electric braking and will instead engage the air braking. However, if the electric braking torque from the drive motor is input into the engine's friction torque, the EBS system interprets this as the hydraulic retarder being off. The EBS system then requests the hydraulic retarder to engage, requesting the vehicle controller to provide a target braking torque. This configuration aims to achieve energy savings.

[0048] Furthermore, since new energy commercial vehicles do not have independent retarders, when the EBS system enters the target braking torque mode, the retarder target torque requested in the first frame is the same as the retarder target braking torque requested. This is the vehicle's braking torque requirement minus the engine friction torque, which is the actual braking torque of the current drive motor. Since the new energy drive motor acts as both an engine and a retarder, the braking torque requested by the vehicle controller for the drive motor, which is the vehicle's braking torque requirement, should be the sum of the current engine friction torque and the retarder target braking torque requested by the EBS, i.e., the sum of the current actual braking torque of the drive motor and the retarder target braking torque requested.

[0049] Based on the above, in the initial stage of EBS system intervention to control the target braking torque during braking, regarding vehicle jerking, since the message period for the engine friction torque signal is 250ms while the message period for the retarder torque signal is 10ms (a difference of 240ms), after the driver depresses the brake pedal, the EBS system calculates the target deceleration based on factors such as the pedal depth and depressing rate. Then, based on the target deceleration, it calculates the vehicle's braking torque requirement, which is the wheel-side braking torque. Subtracting the engine friction torque from the vehicle's braking torque requirement yields the requested retarder target braking torque. For example, under braking conditions, if the driver depresses the brake pedal to 30% after EBS system intervention, the required target acceleration is -2m / s². 2 To achieve -2m / s 2To achieve the target acceleration, the wheel-side braking torque needs to be calculated, for example, if it is 1000N. Wheel-side braking torque = engine friction torque + hydraulic retarder torque. For example, if the detected engine friction torque, i.e., the actual braking torque of the current drive motor, is 500N, then the required hydraulic retarder torque, i.e., the target braking torque of the retarder, is 500N. However, since the drive motor acts as both the engine and the hydraulic retarder, both the engine friction torque and the hydraulic retarder torque actually need to be provided by the drive motor. Therefore, the controller needs to control the output torque of the drive motor to be 500N plus 500N, so the actual output torque required by the drive motor is 1000N.

[0050] S2, determine that the running time of the target braking torque mode is less than or equal to the first preset time, and determine the vehicle braking torque requirement based on the requested target braking torque of the retarder and the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder.

[0051] The first preset time can be set according to the characteristics of the message transmission cycle of the retarder torque signal and the actual braking torque of the current drive motor on the CAN line. For example, the message cycle of the actual braking torque of the current drive motor is 250ms, while the message cycle of the retarder torque signal is 10ms, which is 240ms apart. Therefore, the first preset time can be set to 250ms, but no specific limitation is made here.

[0052] To address the jerking issue, in some embodiments, it is determined that the operating time of the target braking torque mode is less than or equal to a first preset time, and that the requested target braking torque of the retarder is greater than the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder, thereby controlling the vehicle's braking demand torque to follow the requested target braking torque of the retarder; or, it is determined that the operating time of the target braking torque mode is less than or equal to the first preset time, and that the requested target braking torque of the retarder is less than or equal to the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder, using the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder as the vehicle's braking demand torque.

[0053] S3, determine that the running time of the target braking torque mode is greater than the first preset time, and use the requested retarder target braking torque as the vehicle braking demand torque.

[0054] Based on the above, since the message period for engine friction torque is relatively long, typically 250ms, it may not be able to promptly transmit 0 torque to the EBS system, or in extreme cases, there may be a lag of around 250ms. During this lag, the target braking torque calculated by the EBS system for the retarder may be too low. If the vehicle controller directly follows the target braking torque requested by the EBS system at this time, the vehicle's braking torque will decrease, resulting in a decrease in vehicle deceleration. After the engine friction torque is emitted, the target braking torque requested by the EBS system will increase again, and the vehicle deceleration will increase again, resulting in a slight jerking motion in the actual vehicle. To solve the jerking problem, when the vehicle controller receives the first frame of target braking torque mode intervention from the EBS system, it first locks the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder. Within 250ms, if the requested target braking torque of the retarder is greater than the locked torque, the vehicle controller directly follows the requested target braking torque of the retarder, that is, it uses the requested target braking torque of the retarder as the vehicle's braking requirement torque; otherwise, it uses the locked torque. After 250ms, the vehicle controller directly follows the target braking torque requested by EBS, that is, it uses the requested target braking torque of the retarder as the vehicle's braking torque requirement.

[0055] According to the vehicle control method proposed in this embodiment of the invention, when the vehicle is in braking state, the function of the drive motor is replaced by the hydraulic retarder. In the initial stage of the vehicle entering the target braking torque mode, the actual braking torque of the current drive motor is obtained as the sum of the engine friction torque and the requested target braking torque of the retarder, and locked. Based on the running time of the target braking torque mode and the requested target braking torque of the retarder, it is determined whether the vehicle's braking torque requirement follows the requested target braking torque of the retarder or the locked torque is used. This can solve the problem of vehicle jerking in the initial stage of the EBS system entering the target braking torque mode intervention caused by the large difference in the period of the CAN message containing the engine friction torque signal and the retarder torque signal, which leads to torque asynchrony. This ensures that the braking torque output of the drive motor always meets the vehicle's torque requirement, improving the driving stability and safety of the vehicle.

[0056] In some embodiments of the present invention, after determining that the vehicle has entered the target braking torque mode and obtaining the actual braking torque of the current drive motor, the vehicle control method further includes: controlling the operating state of the drive motor according to the braking torque demand of the whole vehicle, and receiving the braking torque signal fed back by the drive motor; putting the braking torque signal into the retarder message, and clearing the actual braking torque of the current drive motor to zero.

[0057] In other words, once the EBS system's target braking torque mode is engaged, the vehicle controller must immediately include the actual braking torque fed back by the drive motor in the retarder message, and the engine friction torque must be simultaneously cleared to zero. The braking torque signal fed back by the drive motor is the actual braking torque fed back by the drive motor, which is entirely provided by the drive motor. Taking the above example: the driver depresses the brake pedal to 30% opening, the required target acceleration is -2 m / s², and the required wheel-side braking torque is 1000 N, because the EBS system considers the engine friction torque when calculating the wheel-side braking torque, if the engine friction torque is maintained continuously, it will cause an EBS calculation error, resulting in the calculated target braking torque requested by the retarder being smaller than 1000 N. Alternatively, due to the relatively long message period of the engine friction torque, the zero torque cannot be transmitted to the EBS in time, and there may be a lag of about 250ms in extreme cases. During this lag, the target braking torque of the retarder calculated by the EBS will be too small. Therefore, after the EBS system intervenes, the engine friction torque needs to be cleared to zero, and the actual braking torque fed back by the drive motor is put into the retarder message.

[0058] In some embodiments of the present invention, such as Figure 4 The diagram shows a flowchart of a vehicle control method according to another embodiment of the present invention, wherein the vehicle control method may include steps S101-S106, as detailed below.

[0059] S101, the actual braking torque of the coasting drive motor is placed in the engine friction signal. That is, under braking conditions, before the target braking torque mode of the EBS system intervenes, the engine friction torque is the current actual braking torque of the drive motor. The current actual braking torque of the drive motor is placed in the engine friction torque, instead of in the retarder message.

[0060] S102, determine whether the target braking torque mode of the EBS system is engaged. If the result is "yes", proceed to step S103. If the result is "no", return to step S101.

[0061] S103 locks the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder, and uses it as the torque request output by the vehicle controller to the drive motor, which is the vehicle's braking torque requirement.

[0062] S104: The braking torque signal fed back by the brake motor is put into the retarder message, the actual braking torque of the current drive motor is cleared, and the timer is started.

[0063] S105, determine whether the vehicle braking torque is greater than the locked torque, or whether the timer is greater than 250ms. If the result is "yes", proceed to step S106. If the result is "no", return to step S104.

[0064] S106, the vehicle controller follows the vehicle braking torque demand under the target braking torque mode.

[0065] In some embodiments of the present invention, such as Figure 5 The diagram shown is a flowchart of a vehicle control method according to another embodiment of the present invention, wherein the vehicle control method may further include steps S10 and S20, as detailed below.

[0066] S10 determines the vehicle's driving intervention mode and braking intervention mode.

[0067] It is understandable that the EBS system supports two intervention modes for both driving and braking: target torque control mode and maximum torque limiting mode. As in the above embodiment, when the vehicle is braking, the EBS system supports both target braking torque mode intervention and braking torque limiting mode intervention. Similarly, when the vehicle is driving, the EBS system supports both target driving torque mode intervention and driving torque limiting mode intervention. Therefore, regardless of whether the vehicle is driving or braking, it is possible for both intervention modes of the EBS system to be present simultaneously. Based on this, whether the vehicle is braking or driving, it is necessary to combine the driving and braking intervention modes to determine the final target torque requested by the vehicle, and the controller will then control the drive motor to provide the target torque requested by the vehicle.

[0068] S20 determines the target torque requested by the vehicle based on the driving intervention method and the braking intervention method.

[0069] Specifically, the driving intervention method and braking intervention method of the EBS system of the present invention can be understood in conjunction with the following embodiments.

[0070] In some embodiments, determining the vehicle target requested torque based on the driving intervention mode and the braking intervention mode includes: determining that the vehicle's driving intervention mode is a target driving torque mode and the vehicle's braking intervention mode is a no-request or braking torque limiting mode, and controlling the vehicle target requested torque to follow the target driving torque mode.

[0071] When a vehicle enters the target drive torque mode, the EBS system may intervene. For example, when driving on icy or snowy roads, if the driver depresses the accelerator pedal significantly, the driving force is strong, and the drive wheels are prone to slippage. The EBS system will intervene to reduce the driving force. Two control methods can be used: torque following and maximum torque limiting. For torque following, the EBS system sends a target torque request to the controller, which then controls the vehicle to follow the torque in the target drive torque mode. For maximum torque limiting, a drive torque limit value can be preset. By ensuring that the vehicle's target requested torque is always less than or equal to this limit value, the driving force is controlled.

[0072] When the vehicle's drive intervention mode is determined to be the target drive torque mode and the braking intervention mode is set to no request, the driver depresses the accelerator pedal. In this driving state, braking is not engaged, but the drive mode is activated, and the vehicle's target requested torque follows the target drive torque mode. However, when the vehicle's drive intervention mode is determined to be the target drive torque mode and the braking intervention mode is set to braking torque limiting mode, the EBS system intervenes in both drive and braking. For example, when the driver depresses the brake pedal, the drive energy is counter-driven by the drive motor. However, at the same time the brake pedal is depressed, air braking may also affect the drive energy, causing the drive energy speed to decrease rapidly. The auxiliary drive energy decreases at a lower wheel speed than the driven energy. In this situation, to prevent tire lock-up, even with the brake pedal depressed, the EBS system will still require the drive motor to output positive torque. This positive torque increases the drive energy wheel speed, ensuring that the driven energy and the driven energy wheel speeds are nearly identical, thus limiting the braking torque. Therefore, in this situation, the EBS system has both a driving target torque request and a braking torque limit. Its driving intervention mode is the target driving torque mode, and its braking intervention mode is the braking torque limit mode. These two modes may work simultaneously. In driving mode, the vehicle's target torque request follows the target driving torque mode.

[0073] Alternatively, determine that the vehicle's braking intervention mode is the target braking torque mode, and determine that the vehicle's driving intervention mode is the no-request or driving torque limiting mode, and control the vehicle's target requested torque to follow the target braking torque mode.

[0074] In cases where the vehicle's braking intervention mode is determined to be the target braking torque mode and the vehicle's drive intervention mode is set to no request, the driver depresses the brake pedal. At this point, the vehicle is in a braking state, drive is not engaged, and the braking mode intervenes, thus the vehicle's target requested torque follows the target braking torque mode. However, in cases where the vehicle's braking intervention mode is determined to be the target braking torque mode and the vehicle's drive intervention mode is set to drive torque limiting mode, the EBS system intervenes in both braking and drive. For example, when the driver depresses the accelerator pedal, the drive motor provides drive energy. However, while the accelerator pedal is depressed, the drive energy may affect braking. In this situation, the EBS system has both a target braking torque request and a drive torque limitation; its braking intervention mode is the target braking torque mode, and its drive intervention mode is the drive torque limiting mode. During braking, the vehicle's target requested torque follows the target braking torque mode.

[0075] In some embodiments of the present invention, determining the target requested torque of the vehicle based on the driving intervention mode and the braking intervention mode further includes: determining that the driving intervention mode of the vehicle is a driving torque limiting mode, the braking intervention mode of the vehicle is no request, and controlling the target requested torque of the vehicle to be less than or equal to the driving torque limiting value.

[0076] Among them, the driving intervention mode for the vehicle is the driving torque limiting mode, and the braking intervention mode for the vehicle is the no-request mode. When the vehicle is in driving mode, in order to avoid the driving wheels from slipping due to the large opening of the accelerator pedal and the strong driving force, a driving torque limiting value is preset to ensure that the target requested torque of the whole vehicle is always less than or equal to the driving torque limiting value, so as to control the driving force. In this mode, the target requested torque of the whole vehicle can be negative, and the driving energy can be dragged by the drive motor.

[0077] In some embodiments, determining the target requested torque of the vehicle based on the driving intervention mode and the braking intervention mode further includes: determining that the driving intervention mode of the vehicle is a driving torque limiting mode and the braking intervention mode of the vehicle is a braking torque limiting mode, obtaining the vehicle torque requirement; and determining the target requested torque of the vehicle based on the driving torque limit value and the braking torque limit value.

[0078] Understandably, both braking and driving modes may intervene in both braking and driving states. This means that under the same operating conditions, the braking torque limiting mode and the driving torque limiting mode may be active simultaneously. Specifically, if both the driving and braking intervention modes are determined to be in driving torque limiting mode, the EBS system will limit both driving and braking torque. For driving torque limiting mode, a pre-set driving torque limit value (maximum driving torque) will ensure that the vehicle's target requested torque is always less than or equal to this limit. Similarly, for braking torque limiting mode, a pre-set braking torque limit value (maximum braking torque) will also be used. However, since braking torque in new energy vehicles is provided by the drive motor in reverse drag, the braking torque provided by the drive motor is actually negative. Therefore, the vehicle's target requested torque will always be greater than or equal to the braking torque limit value.

[0079] In some embodiments, determining the target requested torque of the vehicle based on the drive torque limit, the braking torque limit, and the vehicle torque requirement includes: if the vehicle torque requirement is greater than zero, then 0 ≤ target requested torque of the vehicle ≤ drive torque limit.

[0080] In new energy commercial vehicles, the driving force and braking force are provided by a large drive motor. When the drive motor provides driving force, it converts electrical energy into mechanical energy, and its output driving torque is greater than or equal to zero. When the drive motor provides braking force, it provides braking torque through reverse drag, and thus the braking torque is less than or equal to zero. Based on this, when it is determined that the total vehicle torque requirement is greater than zero, the total vehicle torque requirement is determined as the driving torque, and the vehicle is in a driving state. In this state, although the driving force is provided by the drive motor, its output driving torque is limited. Therefore, the final target torque request issued by the controller must satisfy: 0 ≤ Total vehicle target torque request ≤ Driving torque limit value.

[0081] Alternatively, if the overall vehicle torque requirement is less than zero, then the braking torque limit value ≤ overall vehicle target requested torque ≤ 0. From the above, it can be seen that when the overall vehicle torque requirement is determined to be less than zero, the overall vehicle torque requirement is determined to be the braking torque, and the vehicle is in a braking state. In this state, although the braking force is provided by the brake motor, its output braking torque is limited. Therefore, the final overall vehicle target requested torque issued by the controller must satisfy: braking torque limit value ≤ overall vehicle target requested torque ≤ 0.

[0082] According to the vehicle control method proposed in the embodiments of the present invention, by setting both the driving intervention mode and the braking intervention mode of the vehicle to include a target torque control mode and a maximum torque limiting mode, it is possible for both intervention modes to coexist in the driving state or the braking state. By setting different responses for the driving intervention mode and the braking intervention mode of the EBS system under different operating states of the vehicle, the stability and safety of vehicle driving can be improved.

[0083] In summary, by employing the vehicle control method of this invention in new energy commercial vehicles, the problem of vehicle jerking during the initial intervention phase of the EBS system when entering the target braking torque mode can be solved due to torque asynchrony caused by the large difference in the period of the CAN messages containing the engine friction torque signal and the retarder torque signal. This ensures that the braking torque output of the drive motor always meets the vehicle's required torque. Furthermore, by setting both the vehicle's drive intervention mode and braking intervention mode to include a target torque control mode and a maximum torque limiting mode, and by setting different responses for the EBS system's drive intervention mode and braking intervention mode under different vehicle operating states, the stability, safety, and economy of vehicle driving can be improved through coordinated control of the new energy commercial vehicle's EBS system and vehicle controller.

[0084] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0085] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A vehicle control method, characterized in that, The vehicle includes a drive motor, and the vehicle control method includes: Upon detecting an auxiliary brake lever closing signal, the system determines that the vehicle has entered the target braking torque mode, acquires the current actual braking torque of the drive motor and the requested target braking torque of the retarder, and acquires the sum of the current actual braking torque of the drive motor and the requested target braking torque of the retarder. If the running time of the target braking torque mode is determined to be less than or equal to a first preset time, the vehicle braking demand torque is determined based on the requested target braking torque of the retarder and the sum of the actual braking torque of the current drive motor and the requested target braking torque of the retarder. Specifically, if the running time of the target braking torque mode is determined to be less than or equal to the first preset time, and the requested target braking torque of the retarder is determined to be greater than the sum of the actual braking torque of the current drive motor and the requested target braking torque of the retarder, the vehicle braking demand torque is controlled to follow the requested target braking torque of the retarder. If the running time of the target braking torque mode is determined to be less than or equal to the first preset time, and the requested target braking torque of the retarder is determined to be less than or equal to the sum of the actual braking torque of the current drive motor and the requested target braking torque of the retarder, the sum of the actual braking torque of the current drive motor and the requested target braking torque of the retarder is used as the vehicle braking demand torque. If the operating time of the target braking torque mode is determined to be greater than the first preset time, the target braking torque of the retarder requested is taken as the braking torque required by the whole vehicle.

2. The vehicle control method according to claim 1, characterized in that, After determining that the vehicle has entered the target braking torque mode and obtaining the actual braking torque of the current drive motor, the vehicle control method further includes: Based on the vehicle's braking torque requirement, the system sends control over the operating status of the drive motor and receives the braking torque signal fed back from the drive motor. The braking torque signal is placed into the retarder message, and the actual braking torque of the current drive motor is cleared.

3. The vehicle control method according to claim 1, characterized in that, The vehicle control method further includes: Determine the driving intervention mode and braking intervention mode of the vehicle; The target torque requested by the vehicle is determined based on the driving intervention method and the braking intervention method.

4. The vehicle control method according to claim 3, characterized in that, Determining the target requested torque of the vehicle based on the driving intervention method and the braking intervention method includes: The driving intervention mode is determined to be the target driving torque mode, and the braking intervention mode is determined to be the no-request or braking torque limiting mode, and the vehicle target requested torque is controlled to follow the target driving torque mode; Alternatively, determine that the braking intervention method is the target braking torque mode, and determine that the driving intervention method is an unrequested or driving torque limiting mode, and control the vehicle's target requested torque to follow the target braking torque mode; Alternatively, the driving intervention mode is determined to be the driving torque limiting mode, the braking intervention mode is no request, and the target requested torque of the vehicle is controlled to be less than or equal to the driving torque limiting value.

5. The vehicle control method according to claim 4, characterized in that, Determining the target requested torque of the vehicle based on the driving intervention method and the braking intervention method further includes: The driving intervention mode is determined to be the driving torque limiting mode, and the braking intervention mode is determined to be the braking torque limiting mode; the vehicle torque requirement is obtained. The target requested torque for the vehicle is determined based on the driving torque limit, the braking torque limit, and the overall vehicle torque requirement.

6. The vehicle control method according to claim 5, characterized in that, Determining the target requested torque for the vehicle based on the drive torque limit, the braking torque limit, and the vehicle torque requirement includes: If the vehicle torque requirement is greater than zero, then 0 ≤ the target requested torque of the vehicle ≤ the driving torque limit value; Alternatively, if the vehicle torque requirement is less than zero, then the braking torque limit value ≤ the vehicle target requested torque ≤ 0.

7. A braking system, characterized in that, include: Brake pedal; An auxiliary brake handle, when in the OFF position, is used to provide an auxiliary brake handle closing signal; The drive motor is used to provide driving force and braking force for the entire vehicle; A controller, connected to the brake pedal, the auxiliary brake handle and the drive motor, is used to control the vehicle according to any one of claims 1-6.

8. A vehicle, characterized in that, It includes a vehicle body and the braking system of claim 7, wherein the braking system is disposed on the vehicle body.

9. The vehicle according to claim 8, characterized in that, The vehicle in question is a new energy commercial vehicle.

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