Control method and device for hybrid vehicle

Abstract

The invention discloses a control method and device for a hybrid vehicle and belongs to the technical field of vehicle control, the hybrid vehicle comprises a hybrid system, the hybrid system comprises an electromagnetic one-way clutch, an engine, a generator and a driving motor, and the method comprises the steps that if it is detected that the condition of switching from a series connection mode to a parallel connection mode is met, the hybrid system is started; determining a first target rotating speed of the engine according to the actual rotating speed of the driving motor, a first rotating speed ratio between the driving motor and the engine and a first rotating speed difference threshold value; if the first target rotating speed of the engine is larger than the preset rotating speed threshold value, controlling the actual rotating speed of the engine to reach the preset rotating speed threshold value, and then controlling the electromagnetic one-way clutch to be powered on; and after the electromagnetic one-way clutch is powered on, the actual rotating speed of the engine is controlled to reach the first target rotating speed, and after the actual rotating speed of the engine reaches the first target rotating speed, the absolute value of the torque of the generator is controlled to be reduced to zero, so that the working mode of the hybrid power system is switched from the series connection mode to the parallel connection mode.

Description

Technical Field

[0001] This application belongs to the field of vehicle control technology, and in particular relates to a control method and device for hybrid vehicles. Background Technology

[0002] An electromagnetic one-way clutch engages and disengages the driving and driven ends by changing the position of the rollers in the wedge groove. In hybrid vehicles, when the driving and driven ends of the electromagnetic one-way clutch are disengaged, the range extender, consisting of an engine and a generator, generates electricity and supplies energy to the drive motor, which then drives the vehicle; this mode is called series mode. When the driving and driven ends of the clutch are engaged, the engine can drive the vehicle alone or together with the drive motor; this mode is called parallel mode.

[0003] When hybrid vehicles switch from series to parallel operation, they are prone to failure to engage because the rollers of the electromagnetic one-way clutch cannot be pushed to the narrower end of the wedge groove. Therefore, improving the engagement success rate of the electromagnetic one-way clutch in hybrid vehicles is a pressing issue that needs to be addressed in this field. Summary of the Invention

[0004] The embodiments of this application provide a control method and device for a hybrid vehicle, which can at least to some extent avoid the situation where the roller cannot be pushed to the narrower end of the wedge groove due to excessive centrifugal force caused by the excessive rotation speed of the driving end of the electromagnetic one-way clutch, thereby improving the success rate of engagement between the driving end and the driven end of the electromagnetic one-way clutch.

[0005] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0006] According to a first aspect of the embodiments of this application, a control method for a hybrid vehicle is provided. The hybrid vehicle includes a hybrid system, which includes an electromagnetic one-way clutch, an engine, a generator, and a drive motor. The driving end of the electromagnetic one-way clutch is connected to the engine, and the driven end of the electromagnetic one-way clutch is connected to the drive motor. The engine is also connected to the generator. The method includes: if a condition for switching from a series mode to a parallel mode is detected, determining a first target speed of the engine based on the actual speed of the drive motor, a first speed ratio between the drive motor and the engine, and a first speed difference threshold; if the first target speed of the engine is greater than a preset speed threshold, controlling the actual speed of the engine to reach the preset speed threshold, and then controlling the electromagnetic one-way clutch to be energized; after the electromagnetic one-way clutch is energized, controlling the actual speed of the engine to reach the first target speed; and after the actual speed of the engine reaches the first target speed, controlling the absolute value of the torque of the generator to decrease to zero, so that the operating mode of the hybrid system switches from a series mode to a parallel mode.

[0007] In some embodiments, controlling the absolute value of the generator torque to reduce to zero includes:

[0008] The torque slope of the generator is determined based on the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the resultant torque of the driving end of the electromagnetic one-way clutch. Based on torque slope control, the absolute value of the generator's torque gradually decreases until the absolute value of the generator's torque decreases to zero.

[0009] In some embodiments, determining the torque slope of the generator based on the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the resultant torque of the driving end of the electromagnetic one-way clutch includes: If the speed difference is less than zero and the combined torque of the driving end of the electromagnetic one-way clutch is less than the preset torque, then the torque slope of the generator is determined to be the first slope, where the first slope is greater than zero. If the speed difference is zero, then the torque slope of the generator is determined to be the second slope; where the second slope is greater than the first slope.

[0010] In some embodiments, determining the torque slope of the generator based on the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the resultant torque of the driving end of the electromagnetic one-way clutch includes: If the speed difference is less than zero, and the engagement torque of the electromagnetic one-way clutch reaches the preset torque, then the torque slope of the generator is determined to be zero.

[0011] In some embodiments, the control method for hybrid vehicles further includes: If the speed difference is zero, the engagement torque of the driving end of the electromagnetic one-way clutch is determined based on the actual torque of the engine, the actual torque of the generator, and the second speed ratio between the generator and the engine. The product of the combined torque of the driving end of the electromagnetic one-way clutch and the speed ratio between the driving end of the electromagnetic one-way clutch and the front wheel end is taken as the actual torque of the electromagnetic one-way clutch at the front wheel end. Subtract the actual torque of the electromagnetic one-way clutch at the front wheel end from the total required torque at the front wheel end to obtain the required torque of the drive motor at the front wheel end. Divide the required torque of the drive motor at the front wheel end by the fourth speed ratio between the drive motor and the front wheel end to obtain the first target torque of the drive motor. The actual torque of the drive motor is controlled based on the first target torque.

[0012] In some embodiments, the control method for a hybrid vehicle further includes: If the first target speed is less than or equal to the preset speed threshold, the actual speed of the engine is adjusted to the first target speed, and the actual torque of the engine is controlled based on the actual speed of the engine. Control the energization of the electromagnetic one-way clutch; After the electromagnetic one-way clutch is energized, the absolute value of the generator torque gradually decreases until the absolute value of the generator torque decreases to zero, at which point the hybrid system's operating mode is switched from series mode to parallel mode.

[0013] In some embodiments, the control method for a hybrid vehicle further includes: If the conditions for switching from parallel mode to series mode are detected, the electromagnetic one-way clutch is de-energized, and during the de-energization process, the actual torque of the engine, generator and drive motor is controlled so that the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than zero. After the clutch is de-energized and the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than the second speed difference threshold, the actual speed of the engine is controlled so that the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than or equal to the second speed difference threshold. Switch the operating mode of the hybrid system from parallel mode to series mode.

[0014] In some embodiments, controlling the actual torque of the engine, generator, and drive motor to make the speed difference between the driving and driven ends of the electromagnetic one-way clutch less than zero includes: The second target torque of the engine in the fuel-efficient range is determined based on the actual engine speed. Based on the second target torque and the engine's target moment torque, the engine's actual torque is controlled, where the target moment torque is the engine's actual torque at the moment when it is determined that it needs to switch from parallel mode to series mode. The actual torque of the generator is controlled based on the engine's actual speed, speed difference, and vehicle speed change information. The actual torque of the drive motor is controlled based on the total required torque at the front wheel end, the first speed ratio, the actual torque of the engine, the actual torque of the generator, and the second speed ratio between the generator and the engine.

[0015] In some embodiments, controlling the actual torque of the engine based on a second target torque and a target moment torque of the engine includes: If the second target torque is less than the target torque, then the third target torque of the engine is determined based on the second target torque; If the second target torque is greater than or equal to the target moment torque, then the fourth target torque of the engine at the current moment is determined based on the target moment torque, the second target torque, the maximum output torque of the generator, and the external characteristic torque of the engine. The smaller of the fourth target torque at the current moment and the fourth target torque at the previous moment is determined as the third target torque of the engine. The actual torque of the engine is controlled based on the third target torque.

[0016] In some embodiments, the control method for a hybrid vehicle further includes: If the determined third target torque is less than or equal to zero, then control the engine to cut off fuel and shut down.

[0017] In some embodiments, controlling the actual torque of the generator based on the engine's actual speed, speed difference, and vehicle speed change information includes: The engine torque increment is determined based on the engine's actual speed and speed difference. The fifth target torque of the generator is obtained by taking the negative of the sum of the engine's actual torque and the engine's torque increment, and then dividing it by the second speed ratio. Based on vehicle speed change information, determine the torque change gradient of the generator; The actual torque of the generator is controlled based on the fifth target torque and the torque change gradient.

[0018] In some embodiments, determining the torque change gradient of the generator based on vehicle speed change information includes: If the vehicle speed change information indicates that the vehicle is decelerating or moving at a constant speed, then the torque change gradient of the generator is determined as the first gradient. If the vehicle speed change information represents vehicle acceleration, then the torque change gradient of the generator is determined as the second gradient, where the absolute value of the second gradient is less than the absolute value of the first gradient.

[0019] In some embodiments, controlling the actual torque of the drive motor based on the total required torque at the front wheel end, a first speed ratio, the actual torque of the engine, the actual torque of the generator, and a second speed ratio between the generator and the engine includes: Based on the actual torque of the engine, the actual torque of the generator, and the second speed ratio, the engagement torque of the driving end of the electromagnetic one-way clutch is determined. The product of the combined torque of the driving end of the electromagnetic one-way clutch and the third speed ratio between the driving end of the electromagnetic one-way clutch and the front wheel end is taken as the actual torque of the electromagnetic one-way clutch at the front wheel end. The required torque of the drive motor at the front wheel end is obtained by subtracting the greater of the actual torque and the zero torque of the electromagnetic one-way clutch at the front wheel end from the total required torque at the front wheel end. Divide the required torque of the drive motor at the front wheel end by the fourth speed ratio between the drive motor and the front wheel end to obtain the sixth target torque of the drive motor. The actual torque of the drive motor is controlled based on the sixth target torque.

[0020] In some embodiments, controlling the actual engine speed to make the speed difference between the driving and driven ends of the electromagnetic one-way clutch less than or equal to a second speed difference threshold includes: Based on the actual speed of the drive motor, the first speed ratio, and the second speed difference threshold, the candidate target speed of the engine is determined; The smaller of the candidate target speed and the target speed of the engine in series mode is determined as the second target speed of the engine; The actual engine speed is controlled based on the second target speed.

[0021] According to a second aspect of the embodiments of this application, a control device for a hybrid vehicle is provided, including a processor and a memory. The memory stores computer program instructions that can be executed by the processor. When the processor executes the computer program instructions, it implements the steps of the method as described in any of the first aspects above.

[0022] This application addresses the scenario where the hybrid system switches from a series mode to a parallel mode. After calculating the engine's first target speed, it compares this first target speed with a preset speed threshold. If the first target speed is greater than the preset speed threshold, the electromagnetic one-way clutch is energized once the engine's actual speed reaches the preset speed threshold, rather than energizing it only after the engine's actual speed reaches a higher first target speed. This avoids the rollers failing to be pushed to the narrower end of the wedge groove due to excessive centrifugal force caused by excessively high speed at the driving end of the electromagnetic one-way clutch, thereby improving the success rate of engagement between the driving and driven ends of the electromagnetic one-way clutch.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings: Figure 1 An electrical architecture diagram of a hybrid system according to some embodiments of this application is shown; Figure 2A radial cross-sectional schematic diagram of an electromagnetic one-way clutch according to some embodiments of this application is shown; Figure 3 A flowchart illustrating a control method for a hybrid vehicle according to some embodiments of this application is shown; Figure 4 A flowchart illustrating a control method for a hybrid vehicle according to other embodiments of this application is shown; Figure 5 A flowchart illustrating a control method for a hybrid vehicle according to some embodiments of this application is shown; Figure 6 A block diagram of a control device for a hybrid vehicle according to some embodiments of this application is shown; Figure 7 A schematic diagram of the structure of a control device for a hybrid vehicle according to some embodiments of this application is shown. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0027] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0028] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0029] To enable those skilled in the art to better understand this application, firstly, in conjunction with Figure 1 and Figure 2 A brief explanation of the working principle of the hybrid system and electromagnetic one-way clutch involved in this application is provided.

[0030] Figure 1 An electrical architecture diagram of a hybrid system according to some embodiments of this application is shown. Figure 1 A hybrid system with a configuration of P1+P3+P4 is shown, such as Figure 1 As shown, the hybrid system includes an electromagnetic one-way clutch, an engine, a generator P1, and drive motors (including a front axle drive motor P3 and a rear axle drive motor P4). The driving end of the electromagnetic one-way clutch is connected to the engine, and the driven end of the electromagnetic one-way clutch is connected to the drive motor. The engine is also connected to the generator. Furthermore, the driven end of the electromagnetic one-way clutch is connected to the drive motor via gears, and the engine and generator are also connected via gears.

[0031] It should be noted that this application is applicable not only to hybrid systems with a P1+P3+P4 configuration, but also to hybrid systems with a P1+P3 configuration. For hybrid systems with a P1+P3+P4 configuration, the drive motor mentioned below refers to the front axle drive motor. For hybrid systems with a P1+P3 configuration, since there is only one drive motor, the drive motor mentioned below refers to that drive motor.

[0032] When the driving end of the electromagnetic one-way clutch is disengaged from the driven end, the range extender, consisting of an engine and a generator, generates electricity, and the vehicle is driven only by the drive motor. This mode is called series mode. When the driving end of the clutch is engaged with the driven end, the engine can drive the vehicle alone or together with the drive motor. This mode is called parallel mode.

[0033] It is understandable that the controller for the electromagnetic one-way clutch is the Transmission Control Unit (TCU), the engine controller is the Engine Management System (EMS), the generator controller is the Generator Control Unit (GCU), and the drive motor controller is the Motor Control Unit-Front (MCUF). The Vehicle Control Unit (VCU) interacts with the Generator Control Unit (GCU), Engine Management System (EMS), Transmission Control Unit (TCU), and Motor Control Unit-Front (MCUF) to achieve engine start-stop control, switching control between series and parallel modes of the hybrid system, torque distribution in parallel mode, and generator control in series mode. The engine and generator are located on one side of the driving end of the electromagnetic one-way clutch. When the driving end of the electromagnetic one-way clutch is engaged with the driven end, the engine can transmit positive torque to the wheels to drive them. When the driving end of the electromagnetic one-way clutch is disengaged from the driven end, the engine and wheels are decoupled, and the engine can no longer directly transmit torque to the wheels through the electromagnetic one-way clutch.

[0034] Figure 2 A radial cross-sectional schematic diagram of an electromagnetic one-way clutch according to some embodiments of this application is shown. For example... Figure 2 As shown, the driving end (also called the engine end) of the clutch is the outer ring, and the driven end (also called the wheel end) is the inner ring. In the middle are rollers that transmit torque. The clutch rotates clockwise. The driving end of the clutch, the rollers, and the engine's output shaft rotate synchronously, so the speed of the driving end of the clutch is the same as the engine speed. When the clutch electromagnet is not energized, the clutch's mechanical structure holds the rollers at the wider end of the wedge groove (e.g., ...). Figure 2 As shown in the box on the left), at this time, the driving and driven ends of the clutch are disengaged, and the engine cannot transmit torque to the wheels; when the electromagnet is energized, the mechanical structure of the clutch can push the rollers from the wider end of the wedge groove to the narrower end of the wedge groove (as shown in the box on the left). Figure 2 (As shown in the box on the right) When the speed of the clutch's driving end is equal to the speed of the driven end, the engine torque can be transmitted to the wheel end through the contact surfaces of the rollers and the outer and inner rings. When the speed of the clutch's driving end is less than the speed of the driven end, the engine torque cannot be transmitted to the wheel end through the rollers.

[0035] Figure 3 A flowchart illustrating a control method for a hybrid vehicle according to some embodiments of this application is shown. Figure 3As shown, a control method for a hybrid vehicle is provided, which may include the following steps: Step 301: If the condition for switching from series mode to parallel mode is detected, the first target speed of the engine is determined based on the actual speed of the drive motor, the first speed ratio between the drive motor and the engine, and the first speed difference threshold. Step 302: If the first target speed of the engine is greater than the preset speed threshold, then after the actual speed of the engine reaches the preset speed threshold, the electromagnetic one-way clutch is energized. Step 303: After the electromagnetic one-way clutch is energized, control the actual speed of the engine to reach the first target speed. Step 304: After the engine's actual speed reaches the first target speed, control the absolute value of the generator's torque to decrease to zero, so that the hybrid system's operating mode switches from series mode to parallel mode.

[0036] In step 301, if the vehicle controller detects that the conditions for switching from series mode to parallel mode are met, it determines the first target speed of the engine based on the actual speed of the drive motor, the first speed ratio between the drive motor and the engine, and the first speed difference threshold.

[0037] Specifically, the vehicle controller can determine that the vehicle meets the conditions for switching from series to parallel mode when the hybrid system's operating mode can switch from series to parallel mode and there is a need to switch from series to parallel mode. In some examples, the vehicle controller can determine that the hybrid system's operating mode can switch from series to parallel mode when the vehicle speed is greater than 70 km / h and there is a demand for drive torque; it can also determine that there is a need to switch from series to parallel mode when the energy consumption is lower after switching from series to parallel mode based on vehicle energy economy calculations; and it can further determine that the vehicle meets the conditions for switching from series to parallel mode when the vehicle speed is greater than 70 km / h, there is a demand for drive torque, and the energy consumption is lower after switching from series to parallel mode based on vehicle energy economy calculations.

[0038] In some embodiments, the first target rotational speed can be calculated using the following formula: Formula 1; in, This is the engine's first target speed. This refers to the actual speed of the drive motor. This is the first speed ratio between the drive motor and the engine. This is the first speed difference threshold.

[0039] First speed difference threshold The settings can be adjusted according to the actual situation. Considering that dividing the actual speed of the drive motor by the first speed ratio yields the actual speed of the driven end of the electromagnetic one-way clutch, while the actual speed of the engine is equal to the actual speed of the driving end of the electromagnetic one-way clutch, the first speed difference threshold can be set. Set a smaller speed value, such as 40 rpm or 35 rpm, so that the speed of the driving end of the electromagnetic one-way clutch is slightly less than the speed of the driven end, so that the hybrid system can smoothly transition from series mode to parallel mode.

[0040] In step 302, the preset speed threshold can be set according to the actual situation. In some examples, the preset speed threshold can be 2500 rpm, 2400 rpm, etc.

[0041] It should be noted that, considering that adjusting the speed using the generator control unit is faster and more precise than adjusting the speed using the engine management system, this application, when controlling the actual speed, sends the target speed to the generator control unit, which then controls the actual speed of the engine or generator based on the target speed. When controlling torque, the vehicle controller sends the target torque to the generator control unit, which then controls the actual torque of the generator based on the target torque. The vehicle controller also sends the target torque to the engine management system, which controls the actual torque of the engine based on the target torque. Finally, the vehicle controller sends the target torque to the front motor control unit, which then controls the actual torque of the drive motor based on the target torque.

[0042] If the engine's first target speed is greater than the preset speed threshold, the vehicle controller can convert the preset speed threshold into the generator's target speed through the second speed ratio between the generator and the engine, and then send the generator's target speed to the generator control unit so that the generator control unit can adjust the engine's actual speed to the preset speed threshold.

[0043] During implementation, the "speed synchronization 1" of the electromagnetic one-way clutch is considered complete when the difference between the actual engine speed and a preset speed threshold is within the range of -50 rpm and +30 rpm for a sustained period (e.g., 0.2 s). During "speed synchronization 1," the vehicle controller sends the engine target torque to the engine management system. This target torque is generally within the engine's fuel-efficient range and is related to the engine's actual speed. Specifically, it can be found by looking up the corresponding torque within the fuel-efficient range using the engine's fuel-efficient map and actual engine speed. For example, when the actual engine speed is 1450~2000 rpm, the target torque is 90 Nm; when the actual engine speed is 2000~2500 rpm, the target torque is 110 Nm. After receiving the target torque, the engine management system controls the engine's actual torque based on it.

[0044] After "Speed ​​Synchronization 1" is completed, the vehicle controller sends an electromagnetic one-way clutch engagement request to the transmission control unit. The transmission control unit controls the electromagnet to be energized, and the mechanical structure inside the electromagnetic one-way clutch pushes the roller from the wider end of the wedge groove to the narrower end. During the energization of the electromagnet, the transmission control unit reports the current state of the electromagnetic one-way clutch as "engaged". When the current of the electromagnet reaches the target value, the transmission control unit reports the current state of the electromagnetic one-way clutch as "energization completed" to the vehicle controller. During this process, the generator control unit is always in the "speed control" state, and the engine management system also responds to the engine target torque (e.g., 90 Nm) sent by the vehicle controller.

[0045] In step 303, after the electromagnetic one-way clutch is energized, the generator control unit continues to control the engine speed, adjusting the actual engine speed to reach the first target speed. When the difference between the actual engine speed and the first target speed is within the range of [-50 rpm, +30 rpm] and remains so for a period of time (e.g., 0.2 s), the "speed synchronization 2" of the driving end of the electromagnetic one-way clutch can be considered complete.

[0046] In step 304, after the actual engine speed reaches the first target speed, the vehicle controller can control the absolute value of the generator torque to decrease to zero, and after the absolute value of the generator torque decreases to zero, the hybrid system's operating mode is switched from series mode to parallel mode.

[0047] In some embodiments, the vehicle controller can determine the torque slope of the generator based on the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the combined torque of the driving end of the electromagnetic one-way clutch; and control the absolute value of the generator torque to gradually decrease based on the torque slope until the absolute value of the generator torque decreases to zero.

[0048] During implementation, when "Speed ​​Synchronization 2" is completed and the current state of the electromagnetic one-way clutch is "Electrification Completed", the vehicle controller can control the generator control unit to switch from "Speed ​​Control" to "Torque Control" mode. The vehicle controller can then request to unload the generator's torque according to a calibrable dynamic slope. This slope is related to the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the engagement torque of the driving end of the electromagnetic one-way clutch.

[0049] In some embodiments, if the speed difference is less than zero and the net torque at the driving end of the electromagnetic one-way clutch is less than a preset torque, then the torque slope of the generator is determined to be a first slope, wherein the first slope is greater than zero; if the speed difference is equal to zero, then the torque slope of the generator is determined to be a second slope, wherein the second slope is greater than the first slope. If the speed difference is less than zero and the net torque at the driving end of the electromagnetic one-way clutch reaches a preset torque, then the torque slope of the generator is determined to be zero.

[0050] Understandably, if the speed difference is less than or close to zero (e.g., -10 rpm), and the torque at the driving end of the electromagnetic one-way clutch is less than the preset torque (e.g., 20 Nm), only a portion of the generator torque can be unloaded. If the torque at the driving end of the electromagnetic one-way clutch reaches the preset torque, but the speed difference is not yet zero, the unloading of the generator torque can be paused. The purpose is to allow the driving end of the electromagnetic one-way clutch to engage with the driven end of the electromagnetic one-way clutch with a smaller positive torque, ensuring a smooth transition of the vehicle's front axle from "motor drive" to "engine mechanical drive" in parallel mode, reducing the impact on the rollers of the electromagnetic one-way clutch and the impact on vehicle drivability. When the speed difference reaches 0 rpm or close to zero, the generator torque is unloaded to 0 Nm at a larger slope. When the generator torque is unloaded to 0 Nm, the hybrid system's operating mode is switched to parallel mode, and the generator torque is maintained at 0 Nm during parallel operation.

[0051] By designing a system that switches from series to parallel mode with a smaller combined torque, the electromagnetic one-way clutch can be engaged while the torque impact on the clutch hardware is reduced during engagement, allowing the hybrid system to smoothly transition from series to parallel mode.

[0052] In some embodiments, if the speed difference is zero, the resultant torque of the driving end of the electromagnetic one-way clutch is determined based on the actual torque of the engine, the actual torque of the generator, and the second speed ratio between the generator and the engine. The resultant torque of the driving end of the electromagnetic one-way clutch and the product of the third speed ratio between the driving end of the electromagnetic one-way clutch and the front wheel end are used as the actual torque of the electromagnetic one-way clutch at the front wheel end. The actual torque of the electromagnetic one-way clutch at the front wheel end is subtracted from the total required torque at the front wheel end to obtain the required torque of the drive motor at the front wheel end. The required torque of the drive motor at the front wheel end is divided by the fourth speed ratio between the drive motor and the front wheel end to obtain the first target torque of the drive motor. The actual torque of the drive motor is controlled based on the first target torque.

[0053] Specifically, the first target torque of the drive motor can be calculated using the following formula: Formula 2; in, The first target torque for driving the motor, This represents the total torque required at the front wheels. This is the actual torque of the engine. This is the actual torque of the generator. This is the second speed ratio between the generator and the engine. This is the third speed ratio between the driving end and the front wheel end of the electromagnetic one-way clutch. This is the fourth speed ratio between the drive motor and the front wheel.

[0054] This application addresses the scenario where the hybrid system switches from a series mode to a parallel mode. After calculating the engine's first target speed, it compares this first target speed with a preset speed threshold. If the first target speed is greater than the preset speed threshold, the electromagnetic one-way clutch is energized once the engine's actual speed reaches the preset speed threshold, rather than energizing it only after the engine's actual speed reaches a higher first target speed. This avoids the rollers failing to be pushed to the narrower end of the wedge groove due to excessive centrifugal force caused by the high speed of the electromagnetic one-way clutch's driving end, thereby improving the success rate of engagement between the driving and driven ends of the electromagnetic one-way clutch. By adding a "torque control" stage after the two stages of "speed control," the hybrid system can smoothly transition from a series mode to a parallel mode even at high vehicle speeds.

[0055] Figure 4 A flowchart illustrating a control method for a hybrid vehicle according to other embodiments of this application is shown. For example... Figure 4 As shown, another control method for hybrid vehicles is provided, which includes the following steps: Step 401: If the conditions for switching from series mode to parallel mode are met, the first target speed of the engine is determined based on the actual speed of the drive motor, the first speed ratio between the drive motor and the engine, and the first speed difference threshold. Step 402: If the first target speed is less than or equal to the preset speed threshold, the actual speed of the engine is adjusted to the first target speed, and the actual torque of the engine is controlled based on the actual speed of the engine. Step 403: Control the electromagnetic one-way clutch to be energized; Step 404: After the electromagnetic one-way clutch is energized, the absolute value of the generator torque is gradually reduced until the absolute value of the generator torque is reduced to zero, then the working mode of the hybrid system is switched from series mode to parallel mode.

[0056] Step 401 is implemented in the same way as step 301 above, and will not be described again here.

[0057] Understandably, if the engine's first target speed is less than or equal to a preset speed threshold, the vehicle controller can convert the first target speed into the generator's target speed through the second speed ratio between the generator and the engine, and then send the generator's target speed to the generator control unit so that the generator control unit can adjust the engine's actual speed to the engine's first target speed.

[0058] During implementation, the "speed synchronization 3" of the electromagnetic one-way clutch is considered complete when the difference between the actual engine speed and the first target engine speed is within the range of -50 rpm and +30 rpm for a period of time (e.g., 0.2 s). During "speed synchronization 3," the vehicle controller sends the engine target torque to the engine management system. This target torque is generally within the engine's fuel-efficient range and is related to the engine's actual speed. Specifically, the torque corresponding to the fuel-efficient range can be found based on the engine's fuel-efficient map and the engine's actual speed. For example, when the actual engine speed is 1450~2000 rpm, the engine target torque is 90 Nm; when the actual engine speed is 2000~2500 rpm, the engine target torque is 110 Nm.

[0059] After "Speed ​​Synchronization 3" is completed, the vehicle controller sends an electromagnetic one-way clutch engagement request to the transmission control unit. The transmission control unit controls the electromagnet to be energized, and the mechanical structure inside the electromagnetic one-way clutch pushes the roller from the wider end of the wedge groove to the narrower end. During the energization of the electromagnet, the transmission control unit reports the current state of the electromagnetic one-way clutch as "engaged". When the current of the electromagnet reaches the target value, the transmission control unit reports the current state of the electromagnetic one-way clutch as "energization completed" to the vehicle controller. During this process, the generator control unit is always in the "speed control" state, and the engine management system also responds to the engine target torque (e.g., 90 Nm) sent by the vehicle controller.

[0060] In the implementation process, when "speed synchronization 3" is completed and the current state of the electromagnetic one-way clutch is "energized," the vehicle controller can control the generator control unit to switch from "speed control" to "torque control" mode. The vehicle controller can then request to unload the generator's torque according to a calibrable dynamic slope. This slope is related to the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the net torque of the driving end of the electromagnetic one-way clutch. The specific control process can be referred to in the previous embodiment and will not be repeated here.

[0061] This application addresses the situation where the hybrid system switches from series mode to parallel mode and the first target speed is less than or equal to a preset speed threshold. It first controls the actual engine speed to reach the first target speed before controlling the electromagnetic one-way clutch to be energized. It also adds a "torque control" segment after "speed control" so that the hybrid system can smoothly transition from series mode to parallel mode at low vehicle speeds.

[0062] The above describes the process of a hybrid system switching from series to parallel operation. This process can be summarized in three steps: the generator adjusts the speed, and the engine adjusts the torque; the electromagnetic one-way clutch is energized and engaged; and the torque of the electromagnetic one-way clutch and the drive motor are coordinated and transferred. These three steps complete the switch from series to parallel operation. In parallel mode, the vehicle controller requests torque from the engine and the drive motor respectively according to the torque distribution logic of parallel operation.

[0063] The inventors have also carefully designed the process of switching the operating mode of the hybrid system from parallel mode to series mode. The following will describe in detail the process of switching the operating mode of the hybrid system from parallel mode to series mode.

[0064] Figure 5 A schematic flowchart of a control method for a hybrid vehicle according to some embodiments of this application is shown. Figure 5 As shown, another control method for hybrid vehicles is provided, which includes the following steps: Step 501: If the condition for switching from parallel mode to series mode is detected, the electromagnetic one-way clutch is de-energized, and during the de-energization process, the actual torque of the engine, generator and drive motor is controlled so that the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than zero. Step 502: After the clutch is de-energized and the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than the second speed difference threshold, control the actual speed of the engine so that the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than or equal to the second speed difference threshold. Step 503: Switch the operating mode of the hybrid system from parallel mode to series mode.

[0065] The process of switching from parallel mode to series mode requires first de-energizing the electromagnetic one-way clutch, then adjusting the actual torque of the generator, engine, and drive motor, and finally controlling the speed.

[0066] In step 501, the vehicle controller can determine that the vehicle meets the conditions for switching from parallel mode to series mode when the hybrid system's operating mode can switch from parallel mode to series mode and there is a need to switch from parallel mode to series mode. In some examples, the vehicle controller can determine that the hybrid system's operating mode can switch from parallel mode to series mode when the vehicle speed is less than 65 km / h or the deceleration is less than -0.3g; determine that there is a need to switch from parallel mode to series mode when the energy consumption is lower after switching from parallel mode to series mode through vehicle energy consumption economic calculation; and determine that the vehicle meets the conditions for switching from parallel mode to series mode when the vehicle speed is less than 65 km / h, the deceleration is less than -0.3g, and the energy consumption is lower after switching from parallel mode to series mode through vehicle energy consumption economic calculation.

[0067] When the vehicle meets the conditions for switching from parallel mode to series mode, the vehicle controller can directly request the electromagnet of the electromagnetic one-way clutch to be de-energized, and the transmission control unit enters the electromagnet de-energization process. At the same time, the vehicle controller requests the "torque control" mode and target torque from the generator control unit, engine management system, and front motor control unit respectively, so that the speed difference between the driving and driven ends of the electromagnetic one-way clutch is less than zero.

[0068] In some embodiments, controlling the actual torque of the engine, generator, and drive motor to make the speed difference between the driving and driven ends of the electromagnetic one-way clutch less than zero includes: determining a second target torque corresponding to the engine in the fuel-efficient range based on the engine's actual speed; controlling the engine's actual torque based on the second target torque and the engine's target moment torque, wherein the target moment torque is the engine's actual torque at the moment when it is determined that a switch from parallel mode to series mode is needed; controlling the generator's actual torque based on the engine's actual speed, speed difference, and vehicle speed change information; and controlling the drive motor's actual torque based on the total demand torque at the front wheels, a first speed ratio, the engine's actual torque, the generator's actual torque, and a second speed ratio between the generator and the engine.

[0069] Among them, determining the second target torque of the engine in the fuel-efficient range based on the engine's actual speed can be achieved by finding the torque corresponding to the fuel-efficient range based on the engine's specific fuel consumption map and the engine's actual speed as the second target torque.

[0070] Controlling the engine's actual torque based on the second target torque and the engine's target moment torque can include: if the second target torque is less than the target moment torque, then determining the engine's third target torque based on the second target torque; if the second target torque is greater than or equal to the target moment torque, then determining the engine's fourth target torque at the current moment based on the target moment torque, the second target torque, the generator's maximum output torque, and the engine's external characteristic torque, and determining the smaller of the current moment's fourth target torque and the previous moment's fourth target torque as the engine's third target torque; controlling the engine's actual torque based on the third target torque.

[0071] During implementation, if the second target torque is less than the target moment torque, the vehicle controller can set a third target torque, which decreases to the second target torque according to a certain gradient. If the second target torque is greater than or equal to the target moment torque, the fourth target torque can be determined as min[second target torque, target moment torque, abs (generator torque capacity)]. The second speed ratio between the generator and the engine is -20 Nm, and the engine's external characteristic torque is used. The smaller of the current fourth target torque and the previous fourth target torque is taken as the third target torque to ensure that the engine's actual torque gradually decreases or remains constant. After determining the third target torque, the vehicle controller can send the third target torque to the engine management system, which then controls the engine's actual torque based on the third target torque.

[0072] In some embodiments, if the determined third target torque is less than or equal to zero, the vehicle controller can directly control the engine to cut off fuel and stop, so as to ensure that the driving end of the electromagnetic one-way clutch can disengage.

[0073] In some embodiments, if the actual engine speed is lower than the preset speed (e.g., 750 rpm) during the deparallel connection process, the vehicle controller can also directly request the engine to cut off fuel and stop.

[0074] Controlling the generator's actual torque based on the engine's actual speed, speed difference, and vehicle speed change information can include: determining the engine's torque increment based on the engine's actual speed and speed difference; taking the negative of the sum of the engine's actual torque and the engine's torque increment, and dividing by the second speed ratio to obtain the generator's fifth target torque; determining the generator's torque change gradient based on vehicle speed change information; and controlling the generator's actual torque based on the fifth target torque and the torque change gradient.

[0075] In the implementation process, the engine torque increment (e.g., 30 Nm) can be obtained by looking up a table based on the engine's actual speed and speed difference, and the fifth target torque of the generator can be calculated using the following formula three: Formula 3; Among them, F 发电机5 This is the fifth target torque for the generator. This is the increase in engine torque. This is the second speed ratio between the generator and the engine.

[0076] Determining the torque change gradient of the generator based on vehicle speed change information can include: if the vehicle speed change information indicates that the vehicle is decelerating or moving at a constant speed, then the torque change gradient of the generator is determined as the first gradient; if the vehicle speed change information indicates that the vehicle is accelerating, then the torque change gradient of the generator is determined as the second gradient, wherein the absolute value of the second gradient is less than the absolute value of the first gradient.

[0077] After determining the fifth target torque of the generator and the torque change gradient of the generator, the vehicle controller can send the fifth target torque of the generator and the torque change gradient of the generator to the generator control unit, which then controls the actual torque of the generator based on the fifth target torque of the generator and the torque change gradient of the generator.

[0078] By generating a large absolute negative torque from the generator to reduce the speed of the driving end of the electromagnetic one-way clutch to within a certain range of the speed difference between it and the driven end, the goal of transitioning from parallel mode to series mode (i.e., disengaging from parallel) can be achieved. For example, when disengaging from parallel under deceleration conditions, the absolute value of the generator's torque change gradient is large, allowing the generator's actual torque to quickly reach the fifth target torque. This enables the generator to quickly reduce the speed of the driving end of the electromagnetic one-way clutch to within a certain range of the speed difference between it and the driven end (e.g., the speed of the driving end is more than 100 rpm lower), but without reducing the speed of the driving end of the electromagnetic one-way clutch too low (to avoid the engine's actual speed being too low to operate normally). When disengaging from parallel under acceleration conditions, the absolute value of the generator's torque change gradient is small, allowing the generator's actual torque to reach the fifth target torque more slowly. This suppresses the vehicle jerking problem caused by the rapid decrease in torque at the driving end of the electromagnetic one-way clutch and insufficient torque compensation from the drive motor.

[0079] In some embodiments, controlling the actual torque of the drive motor based on the total required torque at the front wheel end, a first speed ratio, the actual torque of the engine, the actual torque of the generator, and a second speed ratio between the generator and the engine may include: determining the engagement torque of the driving end of the electromagnetic one-way clutch based on the actual torque of the engine, the actual torque of the generator, and the second speed ratio; using the product of the engagement torque of the driving end of the electromagnetic one-way clutch and a third speed ratio between the driving end of the electromagnetic one-way clutch and the front wheel end as the actual torque of the electromagnetic one-way clutch at the front wheel end; subtracting the greater of the actual torque of the electromagnetic one-way clutch at the front wheel end and the zero torque from the total required torque at the front wheel end to obtain the required torque of the drive motor at the front wheel end; dividing the required torque of the drive motor at the front wheel end by a fourth speed ratio between the drive motor and the front wheel end to obtain a sixth target torque of the drive motor; and controlling the actual torque of the drive motor based on the sixth target torque.

[0080] Specifically, the sixth target torque of the drive motor can be calculated using the following formula: Formula 4; in, The sixth target torque for the drive motor, This represents the total torque required at the front wheels. This is the actual torque of the engine. This is the actual torque of the generator. This is the second speed ratio between the generator and the engine. This is the third speed ratio between the driving end and the front wheel end of the electromagnetic one-way clutch. This is the fourth speed ratio between the drive motor and the front wheel end. <0.

[0081] After determining the sixth target torque of the drive motor, the vehicle controller can send the sixth target torque to the front motor control unit, which then controls the actual torque of the drive motor based on the sixth target torque.

[0082] In step 502, the second speed difference threshold can be set according to the actual situation, such as -100rpm, -120rpm, etc.

[0083] When the clutch de-energization is complete, the speed difference between the driving and driven ends of the electromagnetic one-way clutch is less than the second speed difference threshold, and the current state of the electromagnetic one-way clutch is "de-energization complete", the vehicle controller sends the "speed control" mode and the second target speed of the engine to the generator control unit.

[0084] In some embodiments, controlling the actual engine speed so that the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than or equal to a second speed difference threshold may include: determining a candidate target speed of the engine based on the actual speed of the drive motor, a first speed ratio, and the second speed difference threshold; determining the smaller of the candidate target speed and the target speed of the engine in series mode as the second target speed of the engine; and controlling the actual engine speed based on the second target speed.

[0085] Specifically, the second target engine speed can be calculated using the following formula: Formula 5; in, This is the engine's second target speed. This refers to the actual speed of the drive motor. This is the first speed ratio between the drive motor and the engine. The second speed difference threshold, This is the target speed of the engine in series mode.

[0086] In some examples, after determining the second target speed of the engine, the vehicle controller can convert the second target speed into the target speed of the generator by using the second speed ratio between the generator and the engine, and then send the target speed of the generator to the generator control unit so that the generator control unit can adjust the actual speed of the engine to the second target speed.

[0087] In step 503, the vehicle controller can end the deparallel disengagement process after the actual engine speed is maintained at the second target speed for a period of time (e.g., 0.2s), and then switch the hybrid system's operating mode from parallel mode to series mode. During this process, if the second target engine speed is lower than 750rpm, the controller will directly request the engine to cut off fuel and stop.

[0088] This application addresses the scenario where the hybrid system switches from parallel to series operation. By performing "torque control" followed by "speed control," it better controls the engagement torque of the electromagnetic one-way clutch's driving end and the speed difference between the driving and driven ends, ensuring a high success rate for the electromagnetic one-way clutch disengagement. Furthermore, during the torque control process of reversing parallel operation, a torque variation gradient for the generator is designed based on vehicle speed changes, balancing smoothness during both deceleration and acceleration phases. Finally, by designing a system where the engine's target torque does not need to drop to 0 Nm during parallel and reversing operations, the actual engine torque remains within the fuel-efficient range during these processes, while also shortening the time required for parallel and reversing operations.

[0089] The following describes an embodiment of the apparatus described in this application, which can be used to execute the hybrid vehicle control method described in the above embodiments of this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the hybrid vehicle control method described above.

[0090] See Figure 6 This diagram illustrates a block diagram of the control device for a hybrid vehicle according to an embodiment of this application. Figure 6 As shown, the control device for a hybrid vehicle according to an embodiment of this application includes: a speed determination module 601, a first speed control module 602, a second speed control module 603, and a torque control module 604. The speed determination module 601 determines a first target speed of the engine based on the actual speed of the drive motor, a first speed ratio between the drive motor and the engine, and a first speed difference threshold if the conditions for switching from a series mode to a parallel mode are detected. The first speed control module 602 controls the electromagnetic one-way clutch to energize after the actual speed of the engine reaches the preset speed threshold if the first target speed of the engine is greater than the preset speed threshold. The second speed control module 603 controls the actual speed of the engine to reach the first target speed after the electromagnetic one-way clutch is energized. The torque control module 604 controls the absolute value of the generator torque to decrease to zero after the actual speed of the engine reaches the first target speed, thereby switching the operating mode of the hybrid system from a series mode to a parallel mode.

[0091] Based on the same inventive concept, this application also provides a control device for a hybrid vehicle, see reference. Figure 7The diagram shows a schematic of the structure of a control device for a hybrid vehicle according to an embodiment of this application. The control device for the hybrid vehicle includes one or more memories 704, one or more processors 702, and at least one computer program (computer program instruction) stored in the memory 704 and executable on the processor 702. When the processor 702 executes the computer program, it implements the method described above.

[0092] Among them, Figure 7 In this document, a bus architecture (represented by bus 700) is used. Bus 700 may include any number of interconnected buses and bridges, linking various circuits including one or more processors represented by processor 702 and memory represented by memory 704. Bus 700 may also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. Bus interface 705 provides an interface between bus 700 and receiver 701 and transmitter 703. Receiver 701 and transmitter 703 may be the same element, i.e., a transceiver, providing a unit for communicating with various other devices over a transmission medium. Processor 702 is responsible for managing bus 700 and general processing, while memory 704 can be used to store data used by processor 702 during operation.

[0093] Based on the same inventive concept, embodiments of this application provide a computer-readable storage medium storing computer program instructions, which, when executed by a processor, cause the processor to perform the steps of the method described above.

[0094] Based on the same inventive concept, embodiments of this application provide a computer program product, including a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.

[0095] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and embodiments are within the scope and spirit of this application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Furthermore, the functional units may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit.

[0096] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0097] The units described as separate components may or may not be physically separate. Similarly, the components of the control device may or may not be physical units; they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0098] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing computer program instructions, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0099] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A control method for a hybrid vehicle, characterized in that, The hybrid vehicle includes a hybrid system comprising an electromagnetic one-way clutch, an engine, a generator, and a drive motor. The driving end of the electromagnetic one-way clutch is connected to the engine, and the driven end of the electromagnetic one-way clutch is connected to the drive motor. The engine is also connected to the generator. The method includes: If the conditions for switching from series mode to parallel mode are met, the first target speed of the engine is determined based on the actual speed of the drive motor, the first speed ratio between the drive motor and the engine, and the first speed difference threshold. If the first target speed of the engine is greater than the preset speed threshold, then after the actual speed of the engine reaches the preset speed threshold, the electromagnetic one-way clutch is energized. After the electromagnetic one-way clutch is energized, the actual speed of the engine is controlled to reach the first target speed. After the actual speed of the engine reaches the first target speed, the absolute value of the torque of the generator is reduced to zero, so that the operating mode of the hybrid system is switched from series mode to parallel mode.

2. The control method for a hybrid vehicle according to claim 1, characterized in that, The process of reducing the absolute value of the torque of the generator to zero includes: The torque slope of the generator is determined based on the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the combined torque of the driving end of the electromagnetic one-way clutch. The absolute value of the generator's torque is gradually reduced based on the torque slope until the absolute value of the generator's torque is reduced to zero.

3. The control method for a hybrid vehicle according to claim 2, characterized in that, The determination of the generator's torque slope based on the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the resultant torque of the driving end of the electromagnetic one-way clutch includes: If the speed difference is less than zero and the engagement torque of the driving end of the electromagnetic one-way clutch is less than the preset torque, then the torque slope of the generator is determined to be the first slope, wherein the first slope is greater than zero. If the speed difference is zero, then the torque slope of the generator is determined to be a second slope; wherein the second slope is greater than the first slope.

4. The control method for a hybrid vehicle according to claim 3, characterized in that, The determination of the generator's torque slope based on the speed difference between the driving and driven ends of the electromagnetic one-way clutch and the resultant torque of the driving end of the electromagnetic one-way clutch includes: If the speed difference is less than zero, and the engagement torque of the driving end of the electromagnetic one-way clutch reaches the preset torque, then the torque slope of the generator is determined to be zero.

5. The control method for a hybrid vehicle according to claim 2, characterized in that, Also includes: If the speed difference is zero, the engagement torque of the driving end of the electromagnetic one-way clutch is determined based on the actual torque of the engine, the actual torque of the generator, and the second speed ratio between the generator and the engine. The product of the combined torque of the driving end of the electromagnetic one-way clutch and the third speed ratio between the driving end of the electromagnetic one-way clutch and the front wheel end is taken as the actual torque of the electromagnetic one-way clutch at the front wheel end. The required torque of the drive motor at the front wheel end is obtained by subtracting the actual torque of the electromagnetic one-way clutch at the front wheel end from the total required torque at the front wheel end. The first target torque of the drive motor is obtained by dividing the required torque of the drive motor at the front wheel end by the fourth speed ratio between the drive motor and the front wheel end. The actual torque of the drive motor is controlled based on the first target torque.

6. The control method for a hybrid vehicle according to any one of claims 1 to 5, characterized in that, Also includes: If the first target speed is less than or equal to the preset speed threshold, the actual speed of the engine is adjusted to the first target speed, and the actual torque of the engine is controlled based on the actual speed of the engine. Control the energization of the electromagnetic one-way clutch; After the electromagnetic one-way clutch is energized, the absolute value of the generator torque is gradually reduced until the absolute value of the generator torque is reduced to zero, at which point the operating mode of the hybrid system is switched from series mode to parallel mode.

7. The control method for a hybrid vehicle according to any one of claims 1 to 5, characterized in that, Also includes: If the conditions for switching from parallel mode to series mode are detected, the electromagnetic one-way clutch is de-energized, and during the de-energization process, the actual torque of the engine, the generator and the drive motor is controlled so that the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than zero. After the clutch is de-energized and the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than the second speed difference threshold, the actual speed of the engine is controlled so that the speed difference between the driving end and the driven end of the electromagnetic one-way clutch is less than or equal to the second speed difference threshold. The operating mode of the hybrid system is switched from parallel mode to series mode.

8. The control method for a hybrid vehicle according to claim 7, characterized in that, Controlling the actual torque of the engine, the generator, and the drive motor to make the speed difference between the driving and driven ends of the electromagnetic one-way clutch less than zero includes: The second target torque of the engine in the fuel-efficient range is determined based on the actual engine speed. Based on the second target torque and the target moment torque of the engine, the actual torque of the engine is controlled, wherein the target moment torque is the actual torque of the engine at the moment when it is determined that it needs to switch from parallel mode to series mode; The actual torque of the generator is controlled based on the actual engine speed, the speed difference, and the vehicle speed change information. The actual torque of the drive motor is controlled based on the total required torque at the front wheel end, the first speed ratio, the actual torque of the engine, the actual torque of the generator, and the second speed ratio between the generator and the engine.

9. The control method for a hybrid vehicle according to claim 8, characterized in that, The step of controlling the actual torque of the engine based on the second target torque and the engine's target moment torque includes: If the second target torque is less than the target moment torque, then the third target torque of the engine is determined based on the second target torque; If the second target torque is greater than or equal to the target moment torque, then the fourth target torque of the engine at the current moment is determined based on the target moment torque, the second target torque, the maximum output torque of the generator, and the external characteristic torque of the engine, and the smaller of the fourth target torque at the current moment and the fourth target torque at the previous moment is determined as the third target torque of the engine. The actual torque of the engine is controlled based on the third target torque.

10. The control method for a hybrid vehicle according to claim 9, characterized in that, Also includes: If the determined third target torque is less than or equal to zero, then the engine is controlled to cut off fuel and stop.

11. The control method for a hybrid vehicle according to claim 8, characterized in that, The method of controlling the actual torque of the generator based on the actual engine speed, the speed difference, and vehicle speed change information includes: The torque increment of the engine is determined based on the actual engine speed and the speed difference. The fifth target torque of the generator is obtained by taking the opposite of the sum of the actual torque of the engine and the torque increment of the engine, and then dividing it by the second speed ratio. Based on the vehicle speed change information, the torque change gradient of the generator is determined; The actual torque of the generator is controlled based on the fifth target torque and the torque change gradient.

12. The control method for a hybrid vehicle according to claim 11, characterized in that, Determining the torque change gradient of the generator based on the vehicle speed change information includes: If the vehicle speed change information indicates that the vehicle is decelerating or moving at a constant speed, then the torque change gradient of the generator is determined to be the first gradient. If the vehicle speed change information represents vehicle acceleration, then the torque change gradient of the generator is determined to be the second gradient, wherein the absolute value of the second gradient is less than the absolute value of the first gradient.

13. The control method for a hybrid vehicle according to claim 8, characterized in that, The method of controlling the actual torque of the drive motor based on the total required torque at the front wheel end, the first speed ratio, the actual torque of the engine, the actual torque of the generator, and the second speed ratio between the generator and the engine includes: Based on the actual torque of the engine, the actual torque of the generator, and the second speed ratio, the engagement torque of the driving end of the electromagnetic one-way clutch is determined; The product of the combined torque of the driving end of the electromagnetic one-way clutch and the third speed ratio between the driving end of the electromagnetic one-way clutch and the front wheel end is taken as the actual torque of the electromagnetic one-way clutch at the front wheel end. The required torque of the drive motor at the front wheel end is obtained by subtracting the greater of the actual torque and the zero torque of the electromagnetic one-way clutch at the front wheel end from the total required torque at the front wheel end. The sixth target torque of the drive motor is obtained by dividing the required torque of the drive motor at the front wheel end by the fourth speed ratio between the drive motor and the front wheel end. The actual torque of the drive motor is controlled based on the sixth target torque.

14. The control method for a hybrid vehicle according to any one of claims 7 to 13, characterized in that, Controlling the actual speed of the engine to make the speed difference between the driving and driven ends of the electromagnetic one-way clutch less than or equal to the second speed difference threshold includes: Based on the actual speed of the drive motor, the first speed ratio, and the second speed difference threshold, the candidate target speed of the engine is determined; The smaller of the candidate target speed and the target speed of the engine in series mode is determined as the second target speed of the engine; The actual speed of the engine is controlled based on the second target speed.

15. A control device for a hybrid vehicle, comprising a processor and a memory, characterized in that, The memory stores computer program instructions that can be executed by the processor, and when the processor executes the computer program instructions, it implements the steps of the method as described in any one of claims 1 to 14.

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