Vehicle control method and device, vehicle and storage medium

Abstract

The invention provides a vehicle control method and device, a vehicle and a storage medium, the method is applied to the field of vehicles, and the method comprises the steps that under the condition that the vehicle is in a direct drive mode, whether the vehicle is in an emergency braking working condition or not is judged; if the vehicle is in the emergency braking working condition, it is determined that the vehicle needs to be controlled to exit from the direct drive mode, and a target torque reduction gradient in the process that the vehicle exits from the direct drive mode is determined; and according to the target torque reduction gradient, torque reduction of the engine is controlled, and under the condition that the output torque of the engine is reduced to the target torque, a clutch of the vehicle is controlled to be in an open state, so that the vehicle is controlled to exit the direct drive mode. According to the method, the vehicle can be controlled to exit the direct-drive mode in advance, the problem of clutch opening delay is solved, the situation that an engine is reversely dragged is avoided, and the safety of the vehicle is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicles, and more specifically, to a method, a device, a vehicle and a storage medium for controlling a vehicle in the field of vehicles. Background Art

[0002] With the advancement of science and technology and the development of automotive electronics, four-wheel drive hybrid vehicles usually have multiple driving modes including direct drive mode to meet different driving needs. In direct drive mode, the vehicle's clutch is closed, the synchronizer is engaged, and the front drive motor, rear drive motor and engine are all in the driving state to jointly drive the vehicle.

[0003] When the vehicle is in direct drive mode and there is an emergency braking situation, the speed will drop rapidly. Under normal circumstances, as the speed drops rapidly, the vehicle should adjust the current driving mode in time, such as exiting the direct drive mode. However, in the prior art, the direct drive mode can only be exited when the vehicle speed is usually reduced to a certain value, which may cause the vehicle to exit the direct drive mode too late, resulting in the engine and motor torque not being able to be reduced quickly when the speed drops rapidly, which will cause the clutch to open late. This delay may cause the engine to be reverse-dragged (that is, because the wheel speed is lower than the engine speed, the wheels in turn drive the engine to rotate through the transmission system, hindering the normal operation of the engine), which may lead to the risk of stalling and affect the safety of the vehicle. Summary of the invention

[0004] The present application provides a vehicle control method, device, vehicle and storage medium, which can realize early control of the vehicle to exit the direct drive mode, avoid the clutch opening delay problem, avoid the engine being reversely dragged, and improve the safety of the vehicle.

[0005] In a first aspect, a vehicle control method is provided, the method comprising: when the vehicle is in a direct drive mode, determining whether the vehicle is in an emergency braking condition; if the vehicle is in an emergency braking condition, determining that the vehicle needs to be controlled to exit the direct drive mode, and determining a target torque reduction gradient for the vehicle in the process of exiting the direct drive mode; controlling the engine torque reduction according to the target torque reduction gradient, and when the output torque of the engine drops to the target torque, controlling the clutch of the vehicle to be in an open state, so as to control the vehicle to exit the direct drive mode.

[0006] The above technical solution, when the vehicle is in the direct drive mode, determines whether the vehicle is in an emergency braking condition. If the vehicle is in an emergency braking condition, it is determined that the vehicle needs to be controlled to exit the direct drive mode. By accurately identifying whether the vehicle is in an emergency braking condition, and immediately determining to control the vehicle to exit the direct drive mode when the emergency braking condition is identified, there is no need to wait for the vehicle speed to drop to a certain threshold before controlling the vehicle to exit the direct drive mode. Compared with the method in the prior art where the vehicle speed drops to a certain value before exiting the direct drive mode, it is possible to achieve early control of the vehicle to exit the direct drive mode, and can more quickly respond to sudden emergency braking conditions, avoiding the problem of exiting the direct drive mode too late. In addition, the torque reduction gradient during the vehicle exiting the direct drive mode can be determined, so that the engine torque reduction is controlled based on the torque reduction gradient, and when the engine output torque drops to the target torque, the clutch of the vehicle is controlled to be in an open state to control the vehicle to exit the direct drive mode. By accurately controlling the torque reduction, the problem of clutch opening delay caused by the inability to reduce the engine torque in time can be avoided, so that the clutch can be separated in time according to the normal working logic, thereby avoiding the situation where the engine is reversely dragged, and improving the safety of the vehicle.

[0007] In combination with the first aspect, in certain implementations of the first aspect, determining whether the vehicle is in an emergency braking condition includes: obtaining the current speed of the vehicle's transmission input shaft and the actual gear position of the vehicle's front axle; and determining whether the vehicle is in an emergency braking condition based on the current speed and the actual gear position of the front axle.

[0008] In the above technical solution, since the relationship between the transmission input shaft speed and the actual gear position of the front axle is different during emergency braking and normal driving, the accuracy of emergency braking condition judgment can be improved by combining the two parameters of the current speed of the transmission input shaft and the actual gear position of the front axle to determine whether the vehicle is in an emergency braking condition.

[0009] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, judging whether the vehicle is in an emergency braking condition based on the current speed and the actual gear position of the front axle includes: judging whether the actual gear position of the front axle satisfies a preset condition; wherein the preset condition is that the actual gear position of the front axle is in the target gear position and is not in the process of shifting; when it is determined that the actual gear position of the front axle satisfies the preset condition, judging whether the vehicle is in an emergency braking condition based on the current speed of the transmission input shaft and the actual gear position of the front axle; when it is determined that the actual gear position of the front axle does not meet the preset condition, obtaining the acceleration change rate of the vehicle, and judging whether the vehicle is in an emergency braking condition based on the acceleration change rate, the current speed of the transmission input shaft and the actual gear position of the front axle.

[0010] The above technical solution first determines whether the actual gear position of the front axle meets the preset conditions, and then determines different ways of judging whether the vehicle is in an emergency braking condition according to different situations of whether the actual gear position of the front axle meets the preset conditions, which can further improve the accuracy of emergency braking condition judgment.

[0011] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, based on the current speed of the transmission input shaft and the actual gear position of the front axle, determining whether the vehicle is in an emergency braking condition includes: calculating the speed change rate of the transmission input shaft; determining a first speed threshold based on the speed change rate of the transmission input shaft and the actual gear position of the front axle; and determining that the vehicle is in an emergency braking condition when it is determined that the current speed of the transmission input shaft is less than the first speed threshold.

[0012] In the above technical solution, since there is a certain matching relationship between the rotation speed of the transmission input shaft and the actual gear position of the front axle under normal driving conditions, when it is determined that the actual gear position of the front axle meets the preset conditions, it is judged whether the vehicle is in an emergency braking condition based on the current rotation speed of the transmission input shaft and the actual gear position of the front axle, and it is possible to accurately analyze whether an emergency braking situation occurs when the vehicle is driving in a normal gear. And since the speed change rate of the transmission input shaft is relatively stable during normal driving, but will show obvious abnormalities under emergency braking conditions, it is possible to more accurately judge whether the vehicle is in an emergency braking condition based on the speed change rate of the transmission input shaft. Due to the different actual gear positions of the front axle, the speed of the transmission input shaft will be different. Therefore, combining the speed change rate of the transmission input shaft and the actual gear position of the vehicle can more accurately judge whether the vehicle is in an emergency braking condition, reducing the possibility of misjudgment.

[0013] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, based on the acceleration change rate, the current speed of the transmission input shaft and the actual gear position of the front axle, it is determined whether the vehicle is in an emergency braking condition, including: based on the acceleration change rate and the actual gear position of the front axle, determining a second speed threshold; when it is determined that the current speed of the transmission input shaft is less than the second speed threshold, determining that the vehicle is in an emergency braking condition.

[0014] According to the above technical solution, when the actual gear position of the front axle does not meet the preset conditions, it is not accurate to judge whether the vehicle is in an emergency braking condition based on the rotational speed of the transmission input shaft. The vehicle acceleration change rate can be obtained and combined with the current rotational speed of the transmission input shaft and the change in the actual gear position of the front axle to jointly judge whether the vehicle is in an emergency braking condition, thereby further improving the reliability and accuracy of the emergency braking condition judgment.

[0015] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, determining the target torque reduction gradient of the vehicle during the process of exiting the direct drive mode includes: obtaining the gas circuit torque request of the engine of the vehicle, the opening of the accelerator pedal, the current speed of the engine and the opening of the brake pedal; determining the initial torque reduction gradient corresponding to the gas circuit torque request of the engine; determining a first coefficient corresponding to the opening of the accelerator pedal, and determining a second coefficient based on the current speed of the engine and the opening of the brake pedal; and determining the product of the initial torque reduction gradient, the first coefficient and the second coefficient as the target torque reduction gradient of the vehicle during the process of exiting the direct drive mode.

[0016] The above technical solution determines the initial torque reduction gradient by obtaining the gas path torque request of the engine, which can be closely combined with the working requirements of the engine itself to avoid abnormal engine operation due to unreasonable torque reduction. Determining the first coefficient corresponding to the accelerator pedal opening can fully consider the current operation of the driver, so as to flexibly adjust the torque reduction gradient according to the driver's operation. Based on the current engine speed and the brake pedal opening, the second coefficient is determined, which can take into account the braking demand of the vehicle and the actual speed state of the engine, so as to reasonably adjust the torque gradient based on the braking demand of the vehicle and the actual speed of the engine. The product of the initial torque gradient, the first coefficient and the second coefficient is determined as the target torque reduction gradient, which fully considers multiple key factors such as the engine's own working conditions, the driver's power intention and the vehicle's braking state, so that the engine torque can be reduced at a suitable rate, which helps to achieve a smooth transition of mode switching and improve the overall performance and driving experience of the vehicle.

[0017] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, if the vehicle is in an emergency braking condition, the method also includes: obtaining a current speed of the engine of the vehicle; when it is determined that the current speed of the engine is less than a first preset speed, controlling the clutch of the vehicle to be in an open state; when it is determined that the current speed of the engine is less than a second preset speed, controlling the engine to be in a stopped state; wherein the second preset speed is less than the first preset speed.

[0018] The above technical solution can effectively avoid the working condition where the calibration data does not fully cover the working condition by real-time monitoring of the engine speed and taking timely measures. When the current speed of the engine is less than the first preset speed, timely controlling the clutch to open can further reduce the risk of the engine being dragged and stalled. Set a second preset speed lower than the first preset speed, and when the current speed of the engine is less than the second preset speed, timely control the engine to be in a shutdown state. In the case where the engine has been dragged and stalled, requesting the engine to stop to help reset the vehicle's operating mode can prevent the operating mode from getting stuck. A hierarchical control strategy is adopted to take appropriate measures according to different speed ranges, which not only ensures safety but also avoids unnecessary excessive operation. By gradually controlling the state of the clutch and the engine, the safety and stability of the vehicle under emergency braking conditions are ensured, and the risk of accidents is reduced.

[0019] In a second aspect, a vehicle control device is provided, which includes: a judgment module for judging whether the vehicle is in an emergency braking condition when the vehicle is in a direct drive mode; a determination module for determining that the vehicle needs to be controlled to exit the direct drive mode if the vehicle is in an emergency braking condition, and determining a target torque reduction gradient for the vehicle to exit the direct drive mode; a control module for controlling the engine torque reduction according to the target torque reduction gradient, and controlling the clutch of the vehicle to be in an open state when the output torque of the engine drops to the target torque, so as to control the vehicle to exit the direct drive mode.

[0020] In combination with the second aspect, in certain implementations of the second aspect, the judgment module is specifically used to: obtain the current speed of the vehicle's transmission input shaft and the actual gear position of the vehicle's front axle; and based on the current speed and the actual gear position of the front axle, determine whether the vehicle is in an emergency braking condition.

[0021] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the judgment module is also specifically used to: judge whether the actual gear position of the front axle meets the preset conditions; wherein, the preset condition is that the actual gear position of the front axle is in the target gear position and is not in the gear shifting process; when it is determined that the actual gear position of the front axle meets the preset conditions, based on the current speed of the transmission input shaft and the actual gear position of the front axle, judge whether the vehicle is in an emergency braking condition; when it is determined that the actual gear position of the front axle does not meet the preset conditions, obtain the acceleration change rate of the vehicle, and based on the acceleration change rate, the current speed of the transmission input shaft and the actual gear position of the front axle, judge whether the vehicle is in an emergency braking condition.

[0022] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the judgment module includes a first judgment unit, which is specifically used to: calculate the speed change rate of the transmission input shaft; determine a first speed threshold based on the speed change rate of the transmission input shaft and the actual gear position of the front axle; and determine that the vehicle is in an emergency braking condition when it is determined that the current speed of the transmission input shaft is less than the first speed threshold.

[0023] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the judgment module includes a second judgment unit, which is specifically used to: determine a second speed threshold based on the acceleration change rate and the actual gear position of the front axle; and determine that the vehicle is in an emergency braking condition when it is determined that the current speed of the transmission input shaft is less than the second speed threshold.

[0024] In combination with the second aspect and the above-mentioned implementation methods, in certain implementation methods of the second aspect, the determination module is specifically used to: obtain the gas circuit torque request of the vehicle's engine, the opening of the accelerator pedal, the current speed of the engine and the opening of the brake pedal; determine the initial torque reduction gradient corresponding to the gas circuit torque request of the engine; determine a first coefficient corresponding to the opening of the accelerator pedal, and determine a second coefficient based on the current speed of the engine and the opening of the brake pedal; determine the product of the initial torque reduction gradient, the first coefficient and the second coefficient as the target torque reduction gradient when the vehicle exits the direct drive mode.

[0025] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the device also includes a second control module, which is specifically used to: obtain the current speed of the engine of the vehicle; when it is determined that the current speed of the engine is less than the first preset speed, control the clutch of the vehicle to be in an open state; when it is determined that the current speed of the engine is less than the second preset speed, control the engine to be in a stopped state; wherein the second preset speed is less than the first preset speed.

[0026] In a third aspect, a vehicle is provided, comprising a memory and a processor. The memory is used to store executable program code, and the processor is used to call and run the executable program code from the memory, so that the vehicle executes the vehicle control method in the first aspect and any possible implementation of the first aspect.

[0027] In a fourth aspect, a computer program product is provided, which includes: a computer program code, when the computer program code is run on a computer, the computer executes the vehicle control method in the above-mentioned first aspect and any possible implementation of the first aspect.

[0028] In a fifth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the vehicle control method in the above-mentioned first aspect and any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a structural schematic diagram of a hybrid vehicle provided by an embodiment of the present application;

[0030] Figure 2 is a schematic flow chart of a vehicle control method provided in an embodiment of the present application;

[0031] Figure 3 is a structural schematic diagram of a vehicle control device provided in an embodiment of the present application;

[0032] Figure 4 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0034] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0035] Figure 1 This is a schematic diagram of the structure of a hybrid vehicle. Figure 1 As shown, the vehicle 100 includes: a front drive motor 101, a rear drive motor 102, an engine 103, a clutch 104, a front axle transmission 105, a rear axle transmission 106, a front axle differential 107, a rear axle differential 108, front wheels, and rear wheels. The front wheels include a left front wheel 1091 and a right front wheel 1092. The rear wheels include a left rear wheel 1101 and a right rear wheel 1102.

[0036] The front drive motor 101 is arranged on the front axle, and is used to provide power to the front wheels through the front drive shaft to drive the vehicle. The front drive motor 101 is connected to the clutch 104, the first end of the clutch 104 is connected to the engine 103, and the second end of the clutch 104 is connected to the first end of the front axle transmission 105. The second end of the front axle transmission 105 is connected to the front axle differential 107, and the front axle differential 107 is arranged between the left front wheel 1091 and the right front wheel 1092.

[0037] The rear drive motor 102 is arranged on the rear axle, and is used to provide power to the rear wheels through the rear drive shaft to drive the vehicle. The rear drive motor 102 is connected to a first end of a rear axle transmission 106, and a second end of the rear axle transmission 106 is connected to a rear axle differential 108, and the rear axle differential 108 is arranged between the left rear wheel 1101 and the right rear wheel 1102.

[0038] The hybrid vehicle adopting the above-mentioned architecture is equipped with a front drive motor 101, a rear drive motor 102 and an engine 103 at the same time. Therefore, in order to adapt to different road conditions and driving requirements, multiple operating modes including a direct drive mode and a series mode are usually provided.

[0039] In the direct drive mode, the clutch 104 of the vehicle is closed, the front drive motor 101, the rear drive motor 102 and the engine 103 are all in a driving state, and the front drive motor 101, the rear drive motor 102 and the engine 103 jointly drive the vehicle to travel.

[0040] The inventor of the present application has discovered that when an emergency brake is applied to a vehicle in direct drive mode, the vehicle speed will drop rapidly. Under normal circumstances, as the vehicle speed drops rapidly, the vehicle should adjust the current driving mode in a timely manner, such as exiting the direct drive mode. However, in the prior art, the direct drive mode can only be exited when the vehicle speed is reduced to a certain value, which may cause the vehicle to exit the direct drive mode too late. If the vehicle exits the direct drive mode too late, the torque of the engine and the motor may not be reduced quickly when the vehicle speed drops rapidly, which may lead to a delay in clutch opening (the clutch can only be opened when the torque of the engine and the motor drops to 0). This delay may cause the engine to be reversely dragged (that is, because the wheel speed is lower than the engine speed, the wheels in turn drive the engine to rotate through the transmission system, hindering the normal operation of the engine), thereby causing the risk of flameout and affecting the safety of the vehicle.

[0041] In order to solve the above technical problems, an embodiment of the present application provides a vehicle control method, wherein the execution subject of the method is a vehicle, specifically a hybrid control unit (HCU) in the vehicle.

[0042] Figure 2It is a schematic flow chart of a vehicle control method provided in an embodiment of the present application.

[0043] For example, Figure 2 As shown, the method 200 includes:

[0044] S201, when the vehicle is in direct drive mode, determine whether the vehicle is in an emergency braking condition.

[0045] S202: If the vehicle is in an emergency braking condition, it is determined that the vehicle needs to be controlled to exit the direct drive mode, and a target torque reduction gradient is determined during the process of the vehicle exiting the direct drive mode.

[0046] S203, controlling the engine torque reduction according to the target torque reduction gradient, and when the engine output torque drops to the target torque, controlling the vehicle's clutch to be in an open state to control the vehicle to exit the direct drive mode.

[0047] In the embodiment of the present application, when the vehicle is in the direct drive mode, it is determined whether the vehicle is in an emergency braking condition. If the vehicle is in an emergency braking condition, it is determined that the vehicle needs to be controlled to exit the direct drive mode. By accurately identifying whether the vehicle is in an emergency braking condition, and in the case of identifying the emergency braking condition, it is immediately determined to control the vehicle to exit the direct drive mode, without waiting for the vehicle speed to drop to a certain threshold before controlling the vehicle to exit the direct drive mode. Compared with the method in the prior art that the vehicle speed drops to a certain value before exiting the direct drive mode, it is possible to achieve early control of the vehicle to exit the direct drive mode, and can more quickly respond to sudden emergency braking conditions, avoiding the problem of exiting the direct drive mode too late. In addition, the torque reduction gradient during the vehicle exiting the direct drive mode can be determined, so as to control the engine torque reduction based on the torque reduction gradient, and when the output torque of the engine drops to the target torque, the clutch of the vehicle is controlled to be in an open state to control the vehicle to exit the direct drive mode. By accurately controlling the torque reduction, the problem of clutch opening delay caused by the inability to reduce the engine torque in time can be avoided, so that the clutch can be separated in time according to the normal working logic, thereby avoiding the situation where the engine is reversely dragged, and improving the safety of the vehicle.

[0048] Below Figure 2 The specific implementation of each step in the embodiment shown is described as follows:

[0049] As for the above S201, it can be understood that in the direct drive mode, the power transmission between the engine and the wheels is relatively direct, and this connection method makes the operating state of the engine and the motion state of the wheels tightly coupled. Compared with other drive modes, the power transmission path of the direct drive mode is shorter and more direct, and the power response is more direct, but it also means that in some special working conditions such as emergency braking conditions, more complex power system problems may be caused. Based on this, when the vehicle is in the direct drive mode, it is necessary to pay attention to whether the vehicle is currently in a special working condition, so as to take timely measures to ensure the safety of the vehicle.

[0050] Furthermore, when the vehicle is in emergency braking, the vehicle speed will drop sharply. The torque output of the engine and motor is designed based on the normal driving state of the vehicle. If the vehicle is not promptly controlled to exit the direct drive mode, the engine and motor of the vehicle may not be able to adjust the torque in time, which may cause the torque output to not match the actual power required by the wheels, thereby increasing the possibility of accidents.

[0051] Based on this, when the vehicle is in direct drive mode, it is possible to determine in real time whether the vehicle is in an emergency braking condition, so that when the vehicle is in an emergency braking condition, timely measures can be taken to ensure the safety of the vehicle.

[0052] In one possible implementation, determining whether a vehicle is in an emergency braking condition includes: obtaining a current rotational speed of a transmission input shaft of the vehicle and an actual gear position of a front axle of the vehicle; and determining whether the vehicle is in an emergency braking condition based on the current rotational speed and the actual gear position of the front axle.

[0053] It is understood that the above transmission input shaft refers to Figure 1 The input shaft of the front axle transmission shown. The actual gear position of the front axle mentioned above refers to Figure 1 Actual gear position of the front axle transmission shown.

[0054] Furthermore, the transmission input shaft refers to the shaft connecting the engine output end and the front axle transmission. Specifically, in the vehicle's power system, the power generated by the engine is usually transmitted to the transmission input shaft through the clutch. Therefore, the speed of the transmission input shaft is closely related to the speed of the engine.

[0055] The current rotation speed of the transmission input shaft may be acquired via a rotation speed sensor in the vehicle.

[0056] The actual gear position of the front axle determines the transmission ratio between the input shaft and the output shaft of the front axle transmission. The transmission ratio under different gear positions will affect the relationship between the input shaft and the output shaft speed, thereby affecting the characteristics of the entire power transmission system. The actual gear position of the front axle can be obtained through the Electronic Control Unit (ECU) or the Transmission Control Unit (TCU) in the vehicle.

[0057] Furthermore, when the vehicle is running normally, there is a relatively stable matching relationship between the speed of the transmission input shaft and the actual gear position of the front axle to ensure the smooth operation and power output of the vehicle. When the vehicle is in an emergency braking condition, the speed of the vehicle will drop sharply and the wheel speed will drop rapidly. Since there is a mechanical connection between the transmission and the wheels, this will cause the speed of the transmission input shaft to drop rapidly, and the speed of decline is much faster than the rate of change during normal gear shifting or deceleration. Therefore, the current speed of the transmission input shaft can be obtained, and based on this, it can be judged whether the vehicle is in an emergency braking condition. In addition, since the current speed of the transmission input shaft and the actual gear position of the front axle cooperate with each other to achieve power output during normal driving of the vehicle, by simultaneously obtaining the current speed of the transmission input shaft and the actual gear position of the front axle, it is possible to accurately identify whether the vehicle is in an emergency braking condition.

[0058] When the vehicle is in an emergency braking condition, the actual gear position of the front axle usually does not change. However, in some special cases (such as manual gear shifting by the driver, automatic gear shifting when reaching a certain speed, etc.), the actual gear position of the front axle may change. In the process of the actual gear position of the front axle changing, the speed of the transmission input shaft often changes. Therefore, when the actual gear position of the front axle changes, it is not accurate to judge whether the vehicle is in an emergency braking condition based on the current speed of the transmission input shaft. Based on this, different emergency braking condition discrimination methods can be formulated according to the actual situation of the actual gear position of the front axle.

[0059] In one possible implementation, based on the current speed and the actual gear position of the front axle, determining whether the vehicle is in an emergency braking condition includes: determining whether the actual gear position of the front axle meets a preset condition; wherein the preset condition is that the actual gear position of the front axle is in a target gear and is not in the process of shifting; when it is determined that the actual gear position of the front axle meets the preset condition, determining whether the vehicle is in an emergency braking condition based on the current speed of the transmission input shaft and the actual gear position of the front axle; when it is determined that the actual gear position of the front axle does not meet the preset condition, obtaining the acceleration change rate of the vehicle, and determining whether the vehicle is in an emergency braking condition based on the acceleration change rate, the current speed of the transmission input shaft and the actual gear position of the front axle.

[0060] It is understandable that the target gear refers to the expected most suitable gear under the current driving conditions. The not in the gear shifting process refers to the transmission having completed the gear shifting action, the current gear is stable, and there is no ongoing gear shifting operation.

[0061] As mentioned above, if the actual gear position of the front axle meets the preset conditions, it means that the actual gear position of the front axle is not in the gear shifting process and will not change. Therefore, it is possible to directly judge whether the vehicle is in an emergency braking condition based on the current speed of the transmission input shaft and the actual gear position of the front axle.

[0062] In one possible implementation, based on the current speed of the transmission input shaft and the actual gear position of the front axle, determining whether the vehicle is in an emergency braking condition includes: calculating the speed change rate of the transmission input shaft; determining a first speed threshold based on the speed change rate of the transmission input shaft and the actual gear position of the front axle; and determining that the vehicle is in an emergency braking condition when it is determined that the current speed of the transmission input shaft is less than the first speed threshold.

[0063] It is understandable that, as mentioned above, when the vehicle is in an emergency braking condition, the speed of the transmission input shaft will drop rapidly, and the speed of the drop is much faster than the change rate during normal gear shifting or deceleration. Therefore, the speed change rate of the transmission input shaft can be calculated.

[0064] The above speed change rate of the transmission input shaft is used to describe how fast the speed of the transmission input shaft changes over time. The speed change rate = Δn / Δt; where Δn is the speed change of the transmission input shaft (unit: revolutions per minute, rpm); Δt represents the time interval (unit: seconds, s).

[0065] For example, the current speed of the transmission input shaft is 2000 rpm and the speed of the transmission input shaft at 5 seconds before the current moment is 1000 rpm, that is, the above Δn is 1000 rpm, Δt is 5 seconds, and the speed change rate of the transmission input shaft is calculated to be 200 rpm / s.

[0066] Further, after the speed change rate of the transmission input shaft is calculated, a first speed threshold corresponding to two parameters, the speed change rate of the transmission input shaft and the actual gear position of the front axle, can be determined based on a first preset relationship established in advance.

[0067] It is understandable that the first preset relationship is a table or mapping relationship established in advance and can be stored in the vehicle. The first preset relationship can be obtained based on a large amount of experimental data and simulation analysis, and defines the maximum speed threshold corresponding to different conditions (different speed change rates of the transmission input shaft and different actual gear positions of the front axle).

[0068] For example, the maximum speed threshold (in rpm) corresponding to different conditions (different speed change rates of the transmission input shaft and different actual front axle gears) can be determined based on a predefined first preset relationship. The predefined first preset relationship can be shown in the following Table 1:

[0069] Table 1

[0070]

[0071] As shown in Table 1 above, when the speed change rate is the same, the higher the gear, the smaller the corresponding maximum speed threshold will usually be; when the gear is the same, the smaller the absolute value of the speed change rate, the larger the corresponding maximum speed threshold.

[0072] It is understandable that if the actual gear position of the front axle is higher, the transmission ratio is lower, which means that the speed of the input shaft and the output shaft of the front axle transmission are closer. At this time, the speed of the engine or motor directly reflected on the wheel is higher, so at the same speed change rate, a higher input shaft speed may cause the vehicle speed to increase rapidly. Therefore, in the case of a higher gear position, a lower maximum speed threshold can be set.

[0073] If the actual gear of the front axle is low, the transmission ratio is high, which means that the input shaft speed is high and the output shaft speed is low. At this time, the speed of the engine or motor will not be directly reflected in proportion to the wheels, so even if the input shaft speed is high, the actual speed of the vehicle may be low. Therefore, under the same speed change rate, in low gear, a higher maximum speed threshold can be set.

[0074] Furthermore, when the absolute value of the speed change rate of the transmission is large, it means that the vehicle is experiencing a very sharp deceleration. In this case, even if the gear is the same, a lower maximum speed threshold can be set to ensure that the engine or motor does not produce an unstable operating state due to excessive deceleration.

[0075] When the absolute value of the transmission speed change rate is small, it means that the vehicle's deceleration process is relatively gentle. In this case, a higher maximum speed threshold can be set because there is no immediate safety risk and the engine or motor can continue to operate safely at a higher speed.

[0076] For example, if the calculated speed change rate of the transmission input shaft is -500rpm / s, and the actual gear position of the front axle is obtained to be 1st gear, based on the first preset relationship shown in Table 1 above, the corresponding first speed threshold can be determined to be 2800rpm. If the current speed of the transmission input shaft is obtained to be 2500rpm, it is determined that the current speed of the transmission input shaft is less than the first speed threshold, and it can be determined that the vehicle is in an emergency braking condition.

[0077] Furthermore, as mentioned above, if the actual gear position of the front axle does not meet the preset conditions, it means that the actual gear position of the front axle may change during the gear shifting process or because the actual gear position of the front axle is not in the target gear position. If the actual gear position of the front axle changes, the speed of the transmission input shaft will often change. Therefore, when the actual gear position of the front axle changes, it is not accurate to judge whether the vehicle is in an emergency braking condition based on the current speed of the transmission input shaft. Based on this, the acceleration change rate of the vehicle can be introduced to judge whether the vehicle is in an emergency braking condition.

[0078] It is understood that the above acceleration change rate refers to the rate of change of acceleration per unit time, reflecting the tendency of the vehicle to accelerate or decelerate. Under emergency braking conditions, the acceleration change rate of the vehicle is usually a large negative value, indicating that the vehicle is decelerating rapidly. Therefore, by monitoring the acceleration change rate, it is possible to identify the situation where the vehicle is in an emergency braking condition.

[0079] Under different driving conditions, the acceleration change rate of the vehicle will show different changes. Therefore, the acceleration change rate and the actual gear position of the front axle can be combined to determine whether the vehicle is in an emergency braking condition.

[0080] In one possible implementation, based on the acceleration change rate, the current speed of the transmission input shaft and the actual gear position of the front axle, it is determined whether the vehicle is in an emergency braking condition, including: determining a second speed threshold based on the acceleration change rate and the actual gear position of the front axle; and determining that the vehicle is in an emergency braking condition when it is determined that the current speed of the transmission input shaft is less than the second speed threshold.

[0081] It is understandable that after the acceleration change rate of the vehicle is acquired, a second rotation speed threshold corresponding to two parameters, the acceleration change rate of the vehicle and the actual gear position of the front axle, can be determined based on a second preset relationship established in advance.

[0082] It is understandable that the second preset relationship is also a table or mapping relationship established in advance and can be stored in the vehicle. The second preset relationship can be obtained based on a large amount of experimental data and simulation analysis, and defines the maximum speed threshold corresponding to different conditions (different acceleration change rates and different actual front axle gears).

[0083] For example, the maximum speed threshold (in rpm) corresponding to different conditions (different acceleration change rates and different front axle actual gears) can be determined based on a predefined second preset relationship. The predefined second preset relationship can be shown in Table 2 below:

[0084] Table 2

[0085]

[0086] As shown in Table 2 above, when the acceleration change rate is the same, the higher the gear is, the smaller the corresponding maximum speed threshold will be; when the gear is the same, the smaller the absolute value of the acceleration change rate is, the larger the corresponding maximum speed threshold will be.

[0087] It is understandable that if the actual gear position of the front axle is higher, the transmission ratio is lower, which means that when the engine outputs the same torque, the torque obtained by the wheel is relatively small. Under the same acceleration change rate, a higher gear position often requires the engine to output higher power. A higher input shaft speed may also require the engine to output higher power, but the engine's output power is often limited. If a higher input shaft speed is still set, the engine may exceed the preset operating range. Therefore, in the case of a higher gear position, in order to prevent the engine from exceeding the preset operating range, a lower maximum speed threshold can be set.

[0088] If the actual gear position of the front axle is lower, the transmission ratio is higher, which means that when the engine outputs the same torque, the wheel gets a relatively larger torque. Under the same acceleration rate, the engine does not need to output higher power, so even if a higher input shaft speed is set, the engine will not exceed the preset operating range. Therefore, under the same acceleration rate, when the gear position is lower, a higher maximum speed threshold can be set.

[0089] Furthermore, when the absolute value of the acceleration rate of change is small, it means that the vehicle speed changes more slowly. If the absolute value of the acceleration rate of change is small, the vehicle's demand for engine torque output is also small, and there is no need to quickly increase the engine speed to meet the power demand, that is, in the same gear, when the absolute value of the acceleration rate of change is small, the engine can run stably under a relatively low load. Therefore, in the same gear, if the absolute value of the acceleration rate of change is small, a higher maximum speed threshold of the transmission input shaft can be set, so that when the vehicle is in such a driving state with a small absolute value of the acceleration rate of change, the working characteristics of the engine can be better adapted to ensure the smooth and efficient operation of the vehicle power system.

[0090] When the absolute value of the acceleration change rate is large, it means that the faster the vehicle speed changes, the greater the vehicle's demand for engine torque output, and the engine needs to quickly increase the speed to increase the output power to meet the power demand. Since the engine has its own operating range limitations, in order to prevent the engine from exceeding its reasonable operating range due to excessive speed, under the same gear, when the absolute value of the acceleration change rate is large, a lower maximum speed threshold of the transmission input shaft can be set to ensure the stable operation of the vehicle power system and extend the service life of the engine.

[0091] For example, if the acceleration change rate of the vehicle is -4m / s 2 / s, the actual gear position of the front axle is 2nd gear, and based on the second preset relationship shown in Table 2, the corresponding second speed threshold can be determined to be 2600rpm. If the current speed of the transmission input shaft is 2500rpm, it is determined that the current speed of the transmission input shaft is less than the second speed threshold, and it can be determined that the vehicle is in an emergency braking condition.

[0092] The above method first determines whether the actual gear position of the front axle meets the preset conditions, and then determines different ways to determine whether the vehicle is in an emergency braking condition according to different situations of whether the actual gear position of the front axle meets the preset conditions, which can further improve the accuracy of the emergency braking condition judgment. Since there is a certain matching relationship between the rotation speed of the transmission input shaft and the actual gear position of the front axle in the normal driving state, when it is determined that the actual gear position of the front axle meets the preset conditions, it is determined based on the current rotation speed of the transmission input shaft and the actual gear position of the front axle to determine whether the vehicle is in an emergency braking condition, which can accurately analyze whether the vehicle has an emergency braking situation when driving in a normal gear. In the case that the actual gear position of the front axle does not meet the preset conditions, it is not accurate to determine whether the vehicle is in an emergency braking condition based on the rotation speed of the transmission input shaft. The vehicle acceleration change rate can be obtained, and combined with the current rotation speed of the transmission input shaft and the change of the actual gear position of the front axle, it is jointly determined whether the vehicle is in an emergency braking condition, which further improves the reliability and accuracy of the emergency braking condition judgment.

[0093] Furthermore, when it is determined that the vehicle is in an emergency braking condition, an emergency braking flag in the vehicle may be activated.

[0094] As for the above S202, it can be understood that if the vehicle is in an emergency braking condition, the emergency braking flag in the vehicle can be activated immediately. When the emergency braking flag in the vehicle is activated, the direct drive enable flag in the vehicle can be immediately controlled to be reset, that is, the vehicle can be immediately controlled to exit the direct drive mode.

[0095] Furthermore, in the process of controlling the vehicle to exit the direct drive mode, it usually involves the switching of gears and driving modes. In the process of switching gears or driving modes, if the engine output torque is too high, it may impose excessive stress on transmission components such as the transmission and clutch, causing wear or damage to the components. Therefore, in the process of controlling the vehicle to exit the direct drive mode, it is necessary to reduce the engine output torque.

[0096] Generally, when it is determined that the output torque of the engine needs to be reduced, a suitable torque reduction gradient can be determined first.

[0097] For example, the gas circuit torque request of the engine can be obtained, and the corresponding torque reduction gradient can be determined according to the gas circuit torque request. For example, if the gas circuit torque request is low, a higher torque reduction gradient can be set; if the gas circuit torque request is high, a lower torque reduction gradient can be set.

[0098] Furthermore, when it is determined that the vehicle is in an emergency braking condition, the current torque reduction gradient needs to be increased, and the current torque reduction gradient can be corrected in combination with the vehicle's operating parameters.

[0099] In one possible implementation, determining the target torque reduction gradient when the vehicle exits the direct drive mode includes: obtaining the gas circuit torque request of the vehicle's engine, the opening of the accelerator pedal, the current engine speed and the opening of the brake pedal; determining an initial torque reduction gradient corresponding to the gas circuit torque request of the engine; determining a first coefficient corresponding to the opening of the accelerator pedal, and determining a second coefficient based on the current engine speed and the opening of the brake pedal; and determining the product of the torque value, the first coefficient and the second coefficient as the target torque reduction gradient when the vehicle exits the direct drive mode.

[0100] It is understood that the gas circuit torque request of the engine refers to the torque expected to be output by the engine calculated based on the state of the engine intake system, and reflects the maximum possible torque that the engine can provide under the current working condition.

[0101] Exemplarily, the gas path torque request of the above engine may be calculated by the engine controller according to various sensor signals (such as an air flow sensor, an intake pressure sensor, a throttle position sensor, etc.) and a preset control strategy.

[0102] The opening of the accelerator pedal reflects the acceleration demand of the driver and is usually expressed in the form of a percentage (0% to 100%). The opening of the accelerator pedal can be detected by a position sensor installed at the position of the accelerator pedal.

[0103] The above-mentioned current speed of the engine refers to the current operating speed of the engine, and the current speed of the engine usually affects the working state of the engine.

[0104] The opening of the brake pedal reflects the driver's deceleration demand, and is usually expressed in percentage form (0% to 100%). In addition to the opening of the brake pedal, the driver's deceleration demand can also be obtained by obtaining the brake stroke of the brake pedal, that is, the displacement distance of the brake pedal from the initial position to the depressed position. The opening of the brake pedal can be detected by a position sensor installed at the brake pedal position.

[0105] Furthermore, after the gas path torque request of the engine is obtained, the corresponding initial torque reduction gradient can be searched in a pre-established initial torque reduction gradient mapping table. The initial torque reduction gradient mapping table can usually be established through experiments and simulations, and the initial torque reduction gradient mapping table contains initial torque reduction gradients corresponding to different gas path torque request values.

[0106] Exemplarily, in the above initial torque reduction gradient mapping table, the smaller the gas path torque request value of the engine is, the larger the corresponding initial torque reduction gradient is.

[0107] It is understandable that when the vehicle is in an emergency braking condition, the engine output torque needs to be quickly reduced. If the calculated engine gas path torque request value is small, a larger torque reduction gradient needs to be set to ensure that the engine output torque can be quickly reduced.

[0108] Furthermore, when the vehicle is in an emergency braking condition, the driver usually releases the accelerator pedal, resulting in a decrease in the accelerator pedal opening. Therefore, the accelerator pedal opening can also be considered when calculating the target torque reduction gradient, and the coefficient of the torque reduction gradient, i.e., the first coefficient, is determined based on the accelerator pedal opening.

[0109] For example, a first coefficient mapping table between the opening of the accelerator pedal and the first coefficient can be established in advance, wherein the first coefficient mapping table includes first coefficients corresponding to different openings of the accelerator pedal. In the first coefficient mapping table, the larger the opening of the accelerator pedal, the smaller the first coefficient.

[0110] Furthermore, when the vehicle is in an emergency braking condition, in order to ensure the safety of the torque reduction process, the current engine speed and the opening of the brake pedal can also be considered when calculating the target torque reduction gradient, and the coefficient of the torque reduction gradient, i.e., the second coefficient, can be determined based on the current engine speed and the opening of the brake pedal.

[0111] For example, a second coefficient mapping table between the two parameters of the current engine speed and the brake pedal opening and the second coefficient may be established in advance. The second coefficient mapping table may be as shown in Table 3 below:

[0112] Table 3

[0113]

[0114] As shown in Table 3 above, when the current speed of the engine is the same, as the opening of the brake pedal increases, the coefficient of the torque reduction gradient, i.e., the second coefficient, tends to increase; when the opening of the brake pedal is the same, as the current speed of the engine increases, the coefficient of the torque reduction gradient, i.e., the second coefficient, tends to decrease.

[0115] It is understandable that a larger brake pedal opening usually indicates that the driver has a strong braking intention and needs to reduce the torque as soon as possible to assist braking. Therefore, if the current engine speed is the same, a larger second coefficient can be set if the brake pedal opening is larger.

[0116] On the contrary, a smaller opening of the brake pedal may indicate that the driver is only slightly decelerating, and an overly rapid torque reduction strategy is not required at this time. Therefore, if the current engine speed is the same, if the opening of the brake pedal is smaller, a smaller second coefficient can be set.

[0117] When the current engine speed is high, the mechanical parts of the engine and transmission system are under greater stress. If the torque reduction speed is too fast, these parts may be subjected to excessive impact force, increasing the risk of damage. Therefore, if the current engine speed is higher, a smaller second coefficient can be set when the opening of the brake pedal is the same.

[0118] On the contrary, at low speed, the engine responds slowly and may need to reduce torque more quickly to help the vehicle decelerate quickly. Therefore, when the opening of the brake pedal is the same, if the current speed of the engine is lower, a larger second coefficient can be set.

[0119] For example, if the gas circuit torque request of the vehicle engine is 500N·m, the accelerator pedal opening is 0%, the current engine speed is 1000rpm, and the brake pedal opening is 60%, based on the initial torque reduction gradient mapping table, the initial torque reduction gradient corresponding to the gas circuit torque request is determined to be 50N·m / s; based on the first coefficient mapping table, the first coefficient corresponding to the accelerator pedal opening is determined to be 1.2; based on the second coefficient mapping table, the second coefficient corresponding to the two parameters of the current speed and the brake pedal opening is determined to be 5. The product of the initial torque reduction gradient, the first coefficient, and the second coefficient is calculated to be 300N·m / s, and the target torque reduction gradient during the vehicle exiting the direct drive mode can be determined to be 300N·m / s.

[0120] The above method determines the initial torque reduction gradient by obtaining the gas path torque request of the engine, which can be closely combined with the working requirements of the engine itself to avoid abnormal engine operation due to unreasonable torque reduction. Determining the first coefficient corresponding to the accelerator pedal opening can fully consider the current operation of the driver, so as to flexibly adjust the torque reduction gradient according to the driver's operation. Based on the current engine speed and the brake pedal opening, the second coefficient is determined, which can take into account the braking demand of the vehicle and the actual speed state of the engine, so as to reasonably adjust the torque gradient based on the braking demand of the vehicle and the actual speed of the engine. The product of the initial torque gradient, the first coefficient and the second coefficient is determined as the target torque reduction gradient, which fully considers multiple key factors such as the engine's own working conditions, the driver's power intention and the vehicle's braking state, so that the engine torque can be reduced at a suitable rate, which helps to achieve a smooth transition of mode switching and improve the overall performance and driving experience of the vehicle.

[0121] For the above S203, it can be understood that after determining the above target torque reduction gradient, the engine torque reduction can be controlled according to the target torque reduction gradient, and when the output torque of the engine drops to the target torque, the clutch of the vehicle is controlled to be in an open state to control the vehicle to exit the direct drive mode.

[0122] In some embodiments, when the clutch of the vehicle is in an open state, the target gear of the transmission, the first target speed of the motor, and the second target speed of the engine can be determined. Then, the speed of the motor can be adjusted to the first target speed, and the gear of the transmission can be adjusted to the target gear through the TCU, and the speed of the engine can also be adjusted to the second target speed. After the engine speed is adjusted to the target speed, the clutch can be controlled to be in a closed state, and the vehicle can be controlled to enter a new driving mode to complete the exit of the direct drive mode.

[0123] It can be understood that the above-mentioned target gear, first target speed and second target speed can be determined according to the new driving mode to be entered.

[0124] For example, if the vehicle switches from direct drive mode to series mode, the target gear is the gear corresponding to the series mode, the first target speed is the speed suitable for the motor to work in the series mode, and the second target speed is the speed suitable for the engine to work in the series mode.

[0125] For example, in order to reduce the conflict and impact of power transmission during the mode switching process and make the power system transition smoothly, the clutch of the vehicle can be controlled to open when the output torque of the engine is reduced to 0 N·m. That is, the above target torque is set to 0 N·m.

[0126] Furthermore, in the process of controlling the engine's output torque to decrease according to the above-mentioned target torque reduction gradient, if the torque reduction is not timely enough due to untimely response or abnormal calibration data, causing the engine speed to decrease, some remedial measures can be taken quickly to avoid more serious safety problems.

[0127] In one possible implementation, if the vehicle is in an emergency braking condition, the method also includes: obtaining a current speed of the engine of the vehicle; when it is determined that the current speed of the engine is less than a first preset speed, controlling the clutch of the vehicle to be in an open state; when it is determined that the current speed of the engine is less than a second preset speed, controlling the engine to be in a stopped state; wherein the second preset speed is less than the first preset speed.

[0128] It is understandable that the first preset speed can be set according to actual needs, for example, it can be set to be slightly lower than the speed during normal operation of the engine, for example, it can be set to 700 rpm.

[0129] If the current engine speed is less than the first preset speed, it means that the current engine speed is lower than the speed during normal operation, and the engine is at risk of being stalled by reverse drag. In order to avoid the engine being stalled by reverse drag, a request for emergency clutch opening can be immediately sent to the TCU.

[0130] By opening the clutch in an emergency, the connection between the engine and the transmission system can be cut off, which can effectively prevent the wheels from dragging the engine and causing it to stall.

[0131] It should be understood that, when the current speed of the engine is less than the first preset speed, the emergency clutch opening may occur before the engine torque is reduced to the target torque. Since the current speed of the engine is monitored to be less than the first preset speed, it indicates that there is a risk of engine stalling, so the clutch is opened immediately to avoid engine stalling.

[0132] Further, when the current speed of the engine is less than the first preset speed, after the emergency clutch is opened, the above-mentioned operation of exiting the direct drive mode can be continued.

[0133] Exemplarily, the second preset speed may also be set according to actual needs, for example, it may be set lower than the first preset speed, for example, it may be set to 400 rpm.

[0134] If the current engine speed is less than the second preset speed, it means that the current engine speed is already very low, or even the engine may have been stalled. In order to avoid the vehicle's power system from being stuck in the operating mode, the engine can be requested to stop, so that the target operating mode and the actual operating mode of the vehicle are reset to the pure electric mode, so that the vehicle's power system can return to a relatively stable working state.

[0135] It is understandable that when the engine has been stalled, the safety of the vehicle must be ensured first. Normally, the routine operations to exit the direct drive mode can be suspended because the vehicle is in an unstable state after emergency braking. If the complex operations to exit the direct drive mode (such as adjusting the gear, regulating the motor speed, etc.) are continued, it may interfere with the vehicle's braking process or cause other unpredictable problems in the power system.

[0136] If the engine is already in the off state, you can first control the engine to stop, and then switch the vehicle's driving mode to pure electric mode, so as to control the vehicle to stop safely and ensure the safety of the vehicle.

[0137] The above method can effectively avoid the working condition where the calibration data is not fully covered by the working conditions by real-time monitoring of the engine speed and taking timely measures. When the current speed of the engine is less than the first preset speed, timely controlling the clutch to open can further reduce the risk of the engine being stalled by reverse drag. Set a second preset speed lower than the first preset speed, and when the current speed of the engine is less than the second preset speed, timely control the engine to be in a shutdown state. In the case where the engine has been stalled by reverse drag, requesting the engine to stop to help reset the vehicle's operating mode can prevent the operating mode from getting stuck. A hierarchical control strategy is adopted to take appropriate measures according to different speed ranges, which not only ensures safety but also avoids unnecessary excessive operation. By gradually controlling the state of the clutch and the engine, the safety and stability of the vehicle under emergency braking conditions are ensured, and the risk of accidents is reduced.

[0138] Figure 3 It is a structural schematic diagram of a vehicle control device provided in an embodiment of the present application.

[0139] For example, Figure 3 As shown, the device 300 includes:

[0140] The judgment module 301 is used to judge whether the vehicle is in an emergency braking condition when the vehicle is in a direct drive mode.

[0141] The determination module 302 is used to determine that the vehicle needs to be controlled to exit the direct drive mode if the vehicle is in an emergency braking condition, and to determine a target torque reduction gradient during the process of the vehicle exiting the direct drive mode.

[0142] The control module 303 is used to control the engine torque reduction according to the target torque reduction gradient, and when the output torque of the engine drops to the target torque, control the clutch of the vehicle to be in an open state to control the vehicle to exit the direct drive mode.

[0143] In one possible implementation, the judgment module is specifically used to: obtain the current speed of the vehicle's transmission input shaft and the actual gear position of the vehicle's front axle; and based on the current speed and the actual gear position of the front axle, determine whether the vehicle is in an emergency braking condition.

[0144] In one possible implementation, the judgment module is also specifically used to: judge whether the actual gear position of the front axle meets a preset condition; wherein the preset condition is that the actual gear position of the front axle is in the target gear and is not in the gear shifting process; when it is determined that the actual gear position of the front axle meets the preset condition, judge whether the vehicle is in an emergency braking condition based on the current speed of the transmission input shaft and the actual gear position of the front axle; when it is determined that the actual gear position of the front axle does not meet the preset condition, obtain the acceleration change rate of the vehicle, and judge whether the vehicle is in an emergency braking condition based on the acceleration change rate, the current speed of the transmission input shaft and the actual gear position of the front axle.

[0145] In one possible implementation, the judgment module includes a first judgment unit, which is specifically used to: calculate the speed change rate of the transmission input shaft; determine a first speed threshold based on the speed change rate of the transmission input shaft and the actual gear position of the front axle; and determine that the vehicle is in an emergency braking condition when it is determined that the current speed of the transmission input shaft is less than the first speed threshold.

[0146] In one possible implementation, the judgment module includes a second judgment unit, which is specifically used to: determine a second speed threshold based on the acceleration change rate and the actual gear position of the front axle; and determine that the vehicle is in an emergency braking condition when it is determined that the current speed of the transmission input shaft is less than the second speed threshold.

[0147] In one possible implementation, the determination module is specifically used to: obtain the gas circuit torque request of the vehicle's engine, the opening of the accelerator pedal, the current engine speed and the opening of the brake pedal; determine an initial torque reduction gradient corresponding to the gas circuit torque request of the engine; determine a first coefficient corresponding to the opening of the accelerator pedal, and determine a second coefficient based on the current engine speed and the opening of the brake pedal; and determine the product of the initial torque reduction gradient, the first coefficient and the second coefficient as the target torque reduction gradient when the vehicle exits the direct drive mode.

[0148] Optionally, the device also includes a second control module, which is specifically used to: obtain the current speed of the engine of the vehicle; when it is determined that the current speed of the engine is less than a first preset speed, control the clutch of the vehicle to be in an open state; when it is determined that the current speed of the engine is less than a second preset speed, control the engine to be in a stopped state; wherein the second preset speed is less than the first preset speed.

[0149] Figure 4 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0150] For example, Figure 4 As shown, the vehicle 400 includes: a memory 401 and a processor 402, wherein the memory 401 stores an executable program code 4011, and the processor 402 is used to call and execute the executable program code 4011 to perform a vehicle control method.

[0151] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores an executable program code, and the processor is used to call and execute the executable program code to execute a vehicle control method provided by an embodiment of the present application.

[0152] In this embodiment, the functional modules of the device can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0153] In the case of dividing each functional module according to each function, the device may also include a judgment module, a determination module and a control module, etc. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0154] It should be understood that the device provided in this embodiment is used to execute the above-mentioned vehicle control method, and thus can achieve the same effect as the above-mentioned implementation method.

[0155] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is applied to a vehicle, the processing module may be used to control and manage the actions of the vehicle. The storage module may be used to support the vehicle in executing relevant program codes and data.

[0156] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits shown in conjunction with the disclosure of the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0157] In addition, the device provided in the embodiments of the present application may specifically be a chip, a component or a module, and the chip may include a connected processor and a memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a vehicle control method provided in the above embodiments.

[0158] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement a vehicle control method provided by the above embodiment.

[0159] This embodiment also provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement a vehicle control method provided by the above-mentioned embodiment.

[0160] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment is used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here.

[0161] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0162] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0163] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A vehicle control method, characterized in that: The method comprises: When the vehicle is in a direct drive mode, determining whether the vehicle is in an emergency braking condition; If the vehicle is in an emergency braking condition, determining that the vehicle needs to be controlled to exit the direct drive mode, and determining a target torque reduction gradient during the process of the vehicle exiting the direct drive mode; The engine torque reduction is controlled according to the target torque reduction gradient, and when the output torque of the engine drops to the target torque, the clutch of the vehicle is controlled to be in an open state, so as to control the vehicle to exit the direct drive mode.

2. The method according to claim 1, characterized in that The determining whether the vehicle is in an emergency braking condition comprises: Acquiring the current rotation speed of the transmission input shaft of the vehicle and the actual gear position of the front axle of the vehicle; Based on the current rotation speed and the actual gear position of the front axle, it is determined whether the vehicle is in an emergency braking condition.

3. The method according to claim 2, characterized in that The determining whether the vehicle is in an emergency braking condition based on the current speed and the actual gear position of the front axle includes: Determining whether the actual gear position of the front axle meets a preset condition; wherein the preset condition is that the actual gear position of the front axle is in the target gear position and is not in the gear shifting process; In the case where it is determined that the actual gear position of the front axle meets a preset condition, judging whether the vehicle is in an emergency braking condition based on the current rotation speed of the transmission input shaft and the actual gear position of the front axle; When it is determined that the actual gear position of the front axle does not meet the preset conditions, the acceleration change rate of the vehicle is obtained, and based on the acceleration change rate, the current rotational speed of the transmission input shaft and the actual gear position of the front axle, it is determined whether the vehicle is in an emergency braking condition.

4. The method according to claim 3, characterized in that The determining whether the vehicle is in an emergency braking condition based on the current rotation speed of the transmission input shaft and the actual gear position of the front axle includes: Calculating the speed change rate of the transmission input shaft; Determining a first speed threshold value based on a speed change rate of the transmission input shaft and an actual gear position of the front axle; When it is determined that the current rotation speed of the transmission input shaft is less than the first rotation speed threshold, it is determined that the vehicle is in an emergency braking condition.

5. The method according to claim 3, characterized in that: The determining whether the vehicle is in an emergency braking condition based on the acceleration change rate, the current rotation speed of the transmission input shaft and the actual gear position of the front axle includes: Determining a second speed threshold based on the acceleration change rate and the actual gear position of the front axle; When it is determined that the current rotation speed of the transmission input shaft is less than the second rotation speed threshold, it is determined that the vehicle is in an emergency braking condition.

6. The method according to claim 1, characterized in that The determining of the target torque reduction gradient during the process of the vehicle exiting the direct drive mode includes: Obtaining a gas circuit torque request of an engine of the vehicle, an opening of an accelerator pedal, a current speed of the engine, and an opening of a brake pedal; determining an initial torque reduction gradient corresponding to a gas circuit torque request of the engine; determining a first coefficient corresponding to the opening of the accelerator pedal, and determining a second coefficient based on the current speed of the engine and the opening of the brake pedal; The product of the initial torque reduction gradient, the first coefficient and the second coefficient is determined as the target torque reduction gradient when the vehicle exits the direct drive mode.

7. The method according to claim 1, characterized in that If the vehicle is in an emergency braking condition, the method further includes: Obtaining a current speed of an engine of the vehicle; When it is determined that the current speed of the engine is less than a first preset speed, controlling the clutch of the vehicle to be in an open state; When it is determined that the current speed of the engine is less than a second preset speed, the engine is controlled to be in a shutdown state; wherein the second preset speed is less than the first preset speed.

8. A vehicle control device, characterized in that: The device comprises: A judging module, used for judging whether the vehicle is in an emergency braking condition when the vehicle is in a direct drive mode; a determination module, configured to determine that the vehicle needs to be controlled to exit the direct drive mode if the vehicle is in an emergency braking condition, and determine a target torque reduction gradient during the process of the vehicle exiting the direct drive mode; The control module is used to control the engine torque reduction according to the target torque reduction gradient, and when the output torque of the engine drops to the target torque, control the clutch of the vehicle to be in an open state to control the vehicle to exit the direct drive mode.

9. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory, so that the vehicle executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 7 is implemented.

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