Vehicle driving mode switching control method, device, equipment and vehicle

Abstract

Embodiments of the present application provide a kind of vehicle driving mode switching control method, device, equipment and vehicle, it is related to vehicle control technical field.The method comprises: when vehicle meets the enabling condition from series mode to parallel mode, the target speed regulation curve of engine is obtained;According to the curve, the current speed of engine is adjusted, and when the speed difference between current speed and the actual speed of clutch output shaft is less than preset threshold, clutch is controlled to engage;After engagement is completed, engine torque is loaded to crankshaft end, and the power generation torque of starting power generation integrated machine is transferred to drive motor, and mode switching is completed.The method can realize the smooth adjustment of engine speed by pre-acquiring the target speed regulation curve of engine, avoid speed overshoot and oscillation phenomenon, to improve the speed smoothness of series mode switching to parallel mode.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a control method, device, equipment, and vehicle for switching vehicle drive modes. Background Technology

[0002] In actual driving, hybrid vehicles need to switch their driving mode from series mode (where the engine drives the starter generator to generate electricity, and the drive motor drives the wheels) to parallel mode (where the engine and drive motor drive the wheels together) based on driver needs, road conditions, battery charge, and energy management strategies.

[0003] In related technologies, when switching from series mode to parallel mode, the engine speed is usually set as the target value for PID control using the clutch output shaft speed. The engine speed is then adjusted by regulating the engine torque to follow this target. However, using the clutch output shaft speed as the regulation target requires the controller to continuously track the output shaft speed, making it susceptible to operating disturbances, resulting in speed overshoot or oscillation, and poor speed regulation smoothness. Summary of the Invention

[0004] This application provides a control method, device, equipment, and vehicle for switching vehicle drive modes, which can achieve smooth adjustment of engine speed during the process of switching from series mode to parallel mode and improve speed regulation smoothness.

[0005] Firstly, this application provides a control method for switching vehicle drive modes, including:

[0006] When the vehicle meets the preset enabling conditions, the target speed adjustment curve of the engine is obtained. The preset enabling conditions are used to represent the operating conditions required for the vehicle to switch from series mode to parallel mode.

[0007] The engine's current speed is adjusted according to the target speed adjustment curve, and when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold, the clutch is controlled to perform an engagement operation.

[0008] After the clutch is engaged, the engine outputs the required torque at the crankshaft end, and the generated torque of the generator is transferred to the drive motor, completing the switch from the series mode to the parallel mode.

[0009] In one possible implementation, obtaining the target engine speed adjustment curve when the vehicle meets preset enabling conditions includes:

[0010] When the vehicle meets the preset enabling conditions, the initial speed difference between the current speed of the engine and the actual speed of the clutch output shaft is determined;

[0011] According to the preset speed adjustment time, the initial speed difference is smoothly transitioned to the preset speed difference to generate the target speed adjustment curve.

[0012] In one possible implementation, the step of smoothly transitioning the initial speed difference to a preset speed difference according to a preset speed adjustment time, and generating the target speed adjustment curve, includes:

[0013] The preset speed adjustment time is divided into multiple consecutive time points;

[0014] Based on the speed difference smooth transition function and the initial speed difference, the remaining speed difference corresponding to each time point is calculated, and the remaining speed difference corresponding to the last time point among the multiple consecutive time points is the preset speed difference;

[0015] The target speed adjustment curve is generated based on the remaining speed difference corresponding to each time point.

[0016] In one possible implementation, adjusting the engine's current speed according to the target speed adjustment curve, and controlling the clutch to perform an engagement operation when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold, includes:

[0017] When adjusting the current engine speed according to the target speed adjustment curve, a pre-load torque is applied to the clutch to put the clutch in a pre-engaged state;

[0018] When the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than a preset threshold, the pre-load torque is adjusted to the target torque to control the clutch engagement.

[0019] In one possible implementation, applying the pre-load torque to the clutch includes:

[0020] The pre-build-up torque is calculated based on the current engine speed using a proportional-integral control algorithm.

[0021] The pre-built torque is applied to the clutch with a preset slope as a constraint condition.

[0022] In one possible implementation, transferring the generating torque of the integrated generator to the drive motor includes:

[0023] The initial power generation torque of the starter generator is obtained, wherein the initial power generation torque is the current power generation torque of the starter generator when the vehicle meets the preset enabling conditions;

[0024] Using a preset torque transfer rate, the generating torque of the integrated generator is gradually reduced from the initial generating torque to zero, while the generating torque of the drive motor is gradually increased from zero to the initial generating torque.

[0025] In one possible implementation, the preset enabling condition includes at least one of the following:

[0026] The vehicle is powered on and in forward gear;

[0027] The engine is in normal operating condition, and the current speed of the engine is within the preset speed range;

[0028] The vehicle's current speed is greater than or equal to the speed threshold for switching to the parallel mode.

[0029] The clutch is in a fault-free state;

[0030] The discharge power of the power battery is greater than the preset discharge power threshold.

[0031] Secondly, this application provides a control device for switching vehicle driving modes, comprising:

[0032] The first processing module is used to acquire the target speed adjustment curve of the engine when the vehicle meets the preset enabling conditions. The preset enabling conditions are used to represent the operating conditions required for the vehicle to switch from series mode to parallel mode.

[0033] The second processing module is used to adjust the current speed of the engine according to the target speed adjustment curve, and control the clutch to perform an engagement operation when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold.

[0034] The control module is used to control the engine to output the required torque at the crankshaft end after the clutch is engaged, and to transfer the generated torque of the generator to the drive motor, thereby completing the switch from the series mode to the parallel mode.

[0035] Thirdly, this application provides a controller, including: a memory and a processor;

[0036] The memory stores computer-executed instructions;

[0037] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0038] Fourthly, this application provides a vehicle, including: a vehicle body, and a controller as described in the third aspect.

[0039] Fifthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible embodiments of the first aspect.

[0040] In a sixth aspect, this application provides a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0041] This application provides a control method, device, equipment, and vehicle for switching vehicle drive modes, including: when the vehicle meets the enabling conditions for switching from series mode to parallel mode, acquiring the target speed adjustment curve of the engine, adjusting the current speed of the engine according to the curve, and controlling the clutch to engage when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold. After engagement, the engine torque is applied to the crankshaft end, and the generated torque of the starter generator is transferred to the drive motor, completing the mode switching. In the above process, by acquiring the target speed adjustment curve of the engine in advance instead of the traditional method of using the clutch output shaft speed as the PID dynamic tracking target, combined with the clutch timing coordination mechanism driven by speed difference and the torque seamless reconstruction strategy, smooth adjustment of engine speed and precise synchronization of clutch driving and driven ends can be achieved, avoiding speed overshoot, oscillation and engagement shock, reducing the risk of power interruption, and significantly improving the smoothness of speed regulation during the process of switching from series mode to parallel mode. Attached Figure Description

[0042] 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.

[0043] Figure 1 A schematic diagram illustrating the application scenarios provided in the embodiments of this application;

[0044] Figure 2 A flowchart illustrating an embodiment of the vehicle drive mode switching control method provided in this application;

[0045] Figure 3 A flowchart illustrating Embodiment 2 of the vehicle drive mode switching control method provided in this application;

[0046] Figure 4 A schematic diagram of a preset enable condition determination process provided for an embodiment of this application;

[0047] Figure 5 This is a schematic diagram of the speed regulation process provided in the embodiments of this application;

[0048] Figure 6This is a control timing diagram for switching from series mode to parallel mode provided in an embodiment of this application;

[0049] Figure 7 This is a schematic diagram of the structure of the vehicle drive mode switching control device provided in the embodiments of this application;

[0050] Figure 8 This is a schematic diagram of the controller provided in an embodiment of this application.

[0051] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0052] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application.

[0053] Currently, hybrid vehicles, with their balanced advantages in fuel economy and power performance, have become one of the core technological routes for the automotive industry's low-carbon transformation. In actual driving, it is often necessary to dynamically switch between different driving modes based on driver intentions, road conditions, battery state of charge, and energy management strategies. For example, series mode is often used in congested urban traffic, while parallel mode is needed for highway cruising or climbing hills. The smoothness of the transition between these two modes directly affects driving comfort and vehicle power performance.

[0054] In related technologies, when switching from series mode to parallel mode, the engine speed is usually used as the clutch output shaft speed as the PID control target, and the engine torque is adjusted to follow the target change. However, in this method, the controller needs to continuously track the dynamic target, which places a heavy computational burden on it and makes it susceptible to road condition fluctuations, resulting in speed overshoot or oscillation, and making the speed regulation process less smooth.

[0055] To address the aforementioned issues, the inventors considered using a phased collaborative control combined with dynamic timing constraints to improve the smoothness of speed regulation during the transition from series to parallel mode. Based on this, through numerous experiments, the inventors discovered that when the vehicle meets preset enabling conditions, a target engine speed adjustment curve can be obtained. The engine's current speed is adjusted according to this curve, and the clutch engagement is controlled when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold, completing the mode switch. The preset enabling conditions represent the operating requirements for the vehicle to switch from series to parallel mode. In this process, by replacing the traditional PID dynamic tracking method with a pre-planned target speed adjustment curve, combined with a clutch timing coordination strategy driven by speed difference, smooth engine speed regulation can be achieved, avoiding speed overshoot, oscillation, and engagement shock, thereby improving the smoothness of speed regulation during the transition from series to parallel mode. Based on this, this application proposes a control method for vehicle drive mode switching to improve the smoothness of speed regulation during the transition from series to parallel mode.

[0056] Figure 1 This is a schematic diagram illustrating an application scenario provided in an embodiment of this application. Please refer to [link / reference]. Figure 1 When the vehicle is in series mode, the engine drives the starter generator (P1 motor) to generate electricity, which is then used by the drive motor (P3 motor) to drive the wheels. When the vehicle meets preset enabling conditions, the controller can switch the vehicle from series mode to parallel mode. After the switch is complete, the vehicle enters parallel mode, where the engine and drive motor jointly drive the wheels.

[0057] The technical solution of this application and how it solves the above-mentioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0058] Figure 2 This is a flowchart illustrating an embodiment of the vehicle drive mode switching control method provided in this application. Please refer to [link / reference]. Figure 2 The method includes:

[0059] S201. When the vehicle meets the preset enabling conditions, obtain the target speed adjustment curve of the engine.

[0060] The execution entity in this application embodiment can be a controller installed in a vehicle, or a vehicle drive mode switching control device installed in the controller. The vehicle drive mode switching control device can be implemented in software or a combination of software and hardware. The vehicle drive mode switching control device can be a processor in the controller. For ease of understanding, the technical solution of this application will be described below using a controller as an example.

[0061] In this step, when the controller detects that a vehicle operating in series mode meets preset enabling conditions, it can acquire the engine's target speed adjustment curve. The preset enabling conditions represent the operating requirements for the vehicle to switch from series mode to parallel mode.

[0062] Optionally, the preset enable conditions include at least one of the following:

[0063] 1) The vehicle is powered on and in drive;

[0064] Specifically, the vehicle must be powered on and in drive (D) mode; these are the basic prerequisites for mode switching. If the vehicle is not powered on or is in neutral, reverse, or other non-drive gears, the necessary conditions for switching to parallel mode are not met, and the controller should prohibit switching and maintain the current series mode.

[0065] 2) The engine is in normal working condition, and the current engine speed is within the preset speed range;

[0066] Specifically, the engine must be in operation without any shutdown requests, and its current speed should fall within the preset speed range. If the engine speed is too low (such as at idle) or too high (exceeding the speed adjustment limit), it will be difficult to complete a smooth speed adjustment within a reasonable time, which may easily cause speed fluctuations or shocks. Therefore, switching is only allowed under these conditions.

[0067] Optionally, the preset speed range can be calibrated based on the engine's idle speed, maximum permissible speed, and speed regulation quality requirements. For example, the preset speed range can be from 1000 rpm to 4000 rpm, with the lower limit of 1000 rpm slightly higher than the engine idle speed (usually 700-800 rpm) to ensure that the engine has sufficient speed regulation margin; and the upper limit of 4000 rpm lower than the engine's maximum permissible speed (usually 5500-6000 rpm) to avoid entering nonlinear or unstable regions during speed regulation.

[0068] 3) The vehicle's current speed is greater than or equal to the speed threshold for switching to parallel mode;

[0069] Specifically, parallel mode is typically suitable for medium to high-speed driving scenarios. If the vehicle speed is too low, engine intervention may actually increase fuel consumption or cause a jerking sensation. Therefore, a speed threshold needs to be set, allowing the vehicle to switch from series mode to parallel mode only when the current speed reaches or exceeds this threshold, in order to ensure fuel economy and driving smoothness after the switch.

[0070] 4) The clutch is in a fault-free state;

[0071] The clutch is a critical component for switching between series and parallel operation modes. If the clutch malfunctions (such as slippage, inability to disengage or engage, or hydraulic system abnormalities), engagement cannot be completed safely and reliably. Therefore, the clutch must be in a fault-free state before switching modes to avoid power interruption or mechanical damage due to clutch failure.

[0072] 5) The discharge power of the power battery is greater than the preset discharge power threshold.

[0073] In parallel mode, the engine and drive motor jointly drive the wheels. The drive motor needs to obtain sufficient discharge power from the power battery to support its output torque. If the battery discharge power is insufficient, switching to parallel mode may limit the motor output, affecting power response and even causing power fluctuations. Therefore, a discharge power threshold needs to be set. Switching to parallel mode is only allowed when the battery's current available discharge power exceeds this threshold.

[0074] In one specific implementation, when the vehicle meets the preset enabling conditions, the initial speed difference between the current engine speed and the actual speed of the clutch output shaft can be determined, and the initial speed difference can be smoothly transitioned to the preset speed difference according to the preset speed adjustment time to generate the target speed adjustment curve.

[0075] Optionally, the current engine speed and the actual speed of the clutch output shaft can be obtained in the following ways: the current engine speed is acquired in real time by the engine control unit (ECU) through the crankshaft position sensor; the actual speed of the clutch output shaft can be directly measured by the speed sensor set on the clutch output shaft, or it can be calculated based on the speed of the P3 motor and the current gear ratio of the transmission.

[0076] Optionally, the preset speed difference can be zero or a small positive value close to zero. When the preset speed difference is zero, it means that the engine speed needs to be fully synchronized with the clutch output shaft speed before the speed adjustment is considered complete; when the preset speed difference is a small positive value (e.g., 5 rpm), it means that the engine speed is close to the clutch output shaft speed to meet the speed adjustment requirements, which is suitable for operating conditions with high response speed requirements.

[0077] The preset speed adjustment time can be calibrated based on the response speed requirements and speed adjustment smoothness requirements of mode switching. For example, under rapid acceleration conditions, the preset speed adjustment time can be set to a shorter value to quickly respond to the driver's power demand; under normal cruising conditions, the preset speed adjustment time can be set to a longer value to pursue a smoother speed adjustment experience. Optionally, the shorter value can be any time value between 1s and 2s, and the longer value can be any time value between 3s and 5s.

[0078] S202. Adjust the current engine speed according to the target speed adjustment curve, and when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold, control the clutch to perform an engagement operation.

[0079] In this step, the controller can adjust the engine's current speed in real time according to the generated target speed adjustment curve, making the engine speed change smoothly along the curve and gradually approach the actual speed of the clutch output shaft. Simultaneously, during the engine speed adjustment process, the controller can continuously monitor the speed difference between the current engine speed and the actual speed of the clutch output shaft. When the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold, the controller controls the clutch to perform an engagement operation.

[0080] In one specific implementation, when adjusting the current engine speed according to the target speed adjustment curve, a pre-load torque can be applied to the clutch to put the clutch in a pre-tightened state; when the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than a preset threshold, the pre-load torque is adjusted to the target torque to control the clutch engagement.

[0081] The target torque refers to the torque value required for the clutch to fully engage. This torque value is used to fully press the clutch's driving and driven plates together, enabling power transmission between the engine and the drive motor. The target torque can be dynamically determined based on the engine's current output torque, the drive motor's required torque, and the vehicle's operating conditions, or it can be preset to a fixed value based on the clutch characteristics and vehicle calibration results. When the speed difference between the engine's current speed and the actual speed of the clutch output shaft is less than a preset threshold, the clutch torque is gradually increased from the pre-load torque to the target torque, allowing the clutch to fully engage.

[0082] Optionally, the aforementioned preset threshold can be calibrated according to clutch characteristics, vehicle smoothness requirements, and different operating conditions. For example, the preset threshold can be set to 50 rpm, with a range between 30 rpm and 80 rpm, to trigger full clutch engagement. At this point, the engine speed and the clutch output shaft speed are basically synchronized, and the engagement process will not produce significant impact.

[0083] S203. After the clutch is engaged, control the engine to output the required torque at the crankshaft end, and transfer the generated torque of the starter generator to the drive motor to complete the switch from series mode to parallel mode.

[0084] In this step, after the clutch is fully engaged, a mechanical connection is established between the engine and the P3 motor. The controller can control the engine to output the required torque at the crankshaft end, enabling the engine to drive the wheels; at the same time, the power generation torque originally borne by the P1 motor can be gradually transferred to the P3 motor, causing the P3 to exit the driving state and enter the power generation state, achieving a smooth handover of the power generation task, thereby completing the switch from series mode to parallel mode.

[0085] The crankshaft-end torque requirement refers to the engine's target output torque, calculated by the controller based on factors such as driver demand (e.g., accelerator pedal opening), current vehicle speed, and the current output torque of the P3 motor. Specifically, the controller first determines the total vehicle torque requirement based on the accelerator pedal opening and vehicle speed, then subtracts the current output torque of the P3 motor to obtain the crankshaft-end torque requirement. This torque requirement is used to control the engine's fuel injection and air intake, enabling the engine to output the corresponding torque to drive the wheels (at this point, the P3 motor has disengaged from its driving mode and switched to generator mode, no longer outputting driving torque).

[0086] In one specific implementation, the controller can obtain the initial generating torque of the P1 motor (i.e., the current generating torque of the P1 motor when the vehicle meets the preset enabling conditions), and use a preset torque transfer rate to gradually reduce the generating torque of the P1 motor from the initial generating torque to zero, while gradually increasing the generating torque of the P3 motor (also known as the charging torque) from zero to the initial generating torque, so that the two are executed in overlapping time to achieve seamless transfer of generating torque.

[0087] Optionally, the torque transfer rate can be dynamically adjusted according to driving conditions. For example, during rapid acceleration, a faster transfer rate (e.g., 500 N·m / s) can be used to quickly respond to the driver's power demands; during normal cruising, a slower transfer rate (e.g., 100 N·m / s) can be used to achieve a smoother driving experience. The specific value of the torque transfer rate can be determined based on the actual vehicle calibration results.

[0088] In this embodiment, the controller can acquire the target speed adjustment curve of the engine when the vehicle meets preset enabling conditions, adjust the current engine speed according to the curve, and control the clutch to engage when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold. After engagement, the controller controls the engine to output the required torque at the crankshaft end and transfers the generated torque from the generator to the drive motor, completing the switch from series mode to parallel mode. In the above process, by replacing the traditional control method that uses the clutch output shaft speed as the dynamic PID tracking target with a preset target speed adjustment curve, and combining clutch timing coordination driven by speed difference with seamless torque reconstruction, the controller can achieve smooth adjustment of engine speed, precise synchronization of clutch driving and driven ends, and smooth switching of power source. This effectively avoids speed overshoot, oscillation, and engagement shock, reduces the risk of power interruption, and significantly improves the speed regulation smoothness, engagement comfort, and system robustness throughout the entire process of switching from series mode to parallel mode.

[0089] exist Figure 2 Based on the illustrated embodiment, the following, in conjunction with Figure 3 The control method for switching vehicle drive modes described above will be further explained in detail.

[0090] Figure 3 This is a flowchart illustrating a second embodiment of the vehicle drive mode switching control method provided in this application. Please refer to [link / reference]. Figure 3 The method may include:

[0091] S301. When the vehicle meets the preset enabling conditions, determine the initial speed difference between the current engine speed and the actual speed of the clutch output shaft.

[0092] In this step, the controller can first detect whether the vehicle meets the preset enabling conditions. When the conditions are met, the controller can obtain the current engine speed and the actual speed of the clutch output shaft, calculate the difference between the two as the initial speed difference, and lock it.

[0093] For example, if the vehicle is currently in series mode, the engine's current speed is 3000 rpm, and the clutch output shaft's actual speed is 1500 rpm, the initial speed difference between the two is 1500 rpm. If the controller detects that the vehicle meets preset enabling conditions—namely, the vehicle is powered on and in Drive (D) gear, the engine's current speed of 3000 rpm is within the preset speed range of 1000 rpm to 4000 rpm, the current vehicle speed is 60 km / h, which is greater than the speed threshold of 40 km / h for switching to parallel mode, the clutch is functioning properly, and the battery discharge power is 30 kW, which is greater than the preset discharge power threshold of 20 kW—then the initial speed difference of 1500 rpm can be locked for subsequent generation of the target speed adjustment curve.

[0094] S302. According to the preset speed adjustment time, the initial speed difference is smoothly transitioned to the preset speed difference to generate the target speed adjustment curve.

[0095] In this step, the controller can smoothly transition the locked initial speed difference from the current value to the preset speed difference based on the preset speed adjustment time, generating a target speed adjustment curve. This curve is used to plan the trajectory of the engine speed smoothly changing from the current value to the target value (the actual speed of the clutch output shaft).

[0096] In one specific implementation, the preset speed regulation time can be divided into multiple consecutive time points. Based on the speed difference smoothing transition function and the initial speed difference, the remaining speed difference corresponding to each time point is calculated. A target speed regulation curve is then generated based on the remaining speed difference at each time point. The remaining speed difference corresponding to the last time point among the multiple consecutive time points is the preset speed difference.

[0097] The speed difference smoothing transition function describes the change in the remaining speed difference as it gradually decreases to a preset speed difference over time. This function can be a quadratic polynomial function, expressed as y = a + bx + cx², where x is the time variable, y is the remaining speed difference at the current time point, and a, b, and c are correction coefficients. By adjusting the correction coefficients, the rate at which the speed difference decreases can be controlled, ensuring a smooth speed regulation curve in both the initial and final stages and avoiding sudden changes in speed.

[0098] For example, when a rapid response is required, a function with a steeper descent slope can be chosen; when smoothness is desired, a function with a gentler descent slope can be chosen. The specific form of the speed difference smoothing transition function can be determined based on the actual vehicle calibration results, and this application does not impose specific limitations on it.

[0099] For example, taking an initial speed difference of 1500 rpm and a preset speed adjustment time of 3 seconds as an example, the initial speed difference corresponds to the coefficient 'a' in the quadratic polynomial function y = a + bx + cx² (i.e., when x = 0, y = a = 1500 rpm). The controller can divide the 3 seconds into four time points: 0 seconds, 1 second, 2 seconds, and 3 seconds. It then uses a quadratic polynomial function to calculate the remaining speed difference for each time point, which are 1500 rpm, 1000 rpm, 500 rpm, and 0 rpm, respectively. Based on these remaining speed differences, the controller generates a target speed adjustment curve that smoothly transitions from the engine's current speed to the actual speed of the clutch output shaft.

[0100] Optionally, during speed regulation, the controller can maintain the stable generating torque of the P1 motor and prioritize the use of the faster-responding torque of the P3 motor to perform additional speed regulation needs, so as to ensure the smoothness of the speed regulation process.

[0101] S303. When adjusting the current engine speed according to the target speed adjustment curve, apply a pre-load torque to the clutch to put the clutch in a pre-tightened state.

[0102] In this step, the controller can adjust the engine's current speed in real time according to the generated target speed adjustment curve, so that the engine speed changes smoothly along the curve and gradually approaches the actual speed of the clutch output shaft. At the same time as the engine speed adjustment begins, the controller can apply a pre-load torque to the clutch, so that the clutch driving and driven plates begin to contact but transmit almost no torque, preparing for subsequent full engagement.

[0103] In one specific implementation, the controller can calculate the pre-build-up torque using a proportional-integral (PI) control algorithm. Specifically, the pre-build-up torque can be calculated based on the engine's current speed using the PI control algorithm; and the pre-build-up torque can be applied to the clutch using a preset slope as a constraint.

[0104] For example, the controller can obtain the P-term torque component by multiplying the derivative of the engine's current speed by the moment of inertia and then by a coefficient for the P-term. It can then look up the upper and lower limits of the I-term torque based on the current engine speed, and obtain the I-term torque component after integral adjustment. The P-term torque component and the I-term torque component are then superimposed to obtain the pre-setup torque. During the application of the pre-setup torque, the controller uses a preset slope as a constraint condition to limit the rate of torque change to no more than this slope, thereby avoiding sudden torque changes.

[0105] Formula (1)

[0106] in, For pre-built-up torque; This is the current clutch torque (0 at the start of the pre-load build-up phase, gradually increasing with the control cycle). To control the cycle; The preset slope (N·m / s) (also the maximum allowable slope) is used to limit the rate of torque change and prevent sudden torque changes.

[0107] Using formula (1), the controller can calculate the torque change rate at the current moment in each control cycle and update the current torque of the clutch accordingly. When the difference between the pre-load torque and the current torque is large, the actual change rate is limited by the preset slope. The current torque increases smoothly at a constant rate; when the difference is small, the actual rate of change gradually decreases, and the current torque gradually converges to the pre-built torque.

[0108] For example, current torque =0 N·m, pre-built torque value =30 N·m, control period =0.01s, preset slope =100 N·m / s, then the ideal rate of change is (30-0) / 0.01=3000 N·m / s, but limited by the preset slope S, the actual rate of change is min(3000,100)=100 N·m. Therefore, the current torque of the clutch is... It will smoothly increase from 0 to 30 N·m within 0.3s, allowing the clutch to smoothly enter the pre-clamping state.

[0109] S304. When the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than a preset threshold, the pre-built torque is adjusted to the target torque to control clutch engagement.

[0110] In this step, the controller continuously monitors the speed difference between the current engine speed and the actual speed of the clutch output shaft. When this speed difference is less than a preset threshold, the clutch torque can be adjusted from the pre-set torque to the target torque, controlling the clutch to fully engage.

[0111] Optionally, during the process of adjusting the pre-built torque to the target torque, the controller also adopts the method shown in formula (1), with a preset slope as a constraint condition, to limit the torque change rate to not exceed the slope, so that the clutch torque can smoothly increase from the pre-built torque to the target torque.

[0112] For example, after the clutch torque preload is completed, the controller continues to adjust the engine speed until the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than or equal to 50 rpm. At this point, the controller can adjust the clutch torque from the preload torque to the target torque, controlling the clutch to fully engage. If the speed difference condition is not met, the speed adjustment operation continues until the speed difference reaches the target before engaging the clutch.

[0113] In one optional implementation, a first preset threshold and a second preset threshold can be set during engine speed regulation, wherein the second preset threshold is less than the first preset threshold. When the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than or equal to the first preset threshold, a pre-load torque is applied to the clutch to put the clutch in a pre-compression state; when the speed difference further decreases to less than or equal to the second preset threshold, the clutch is controlled to fully engage.

[0114] S305. After the clutch is engaged, control the engine to output the required torque at the crankshaft end and obtain the initial generating torque of the starter generator.

[0115] In this step, after the clutch is fully engaged, the controller can request the engine to output the required torque at the crankshaft end, so that the engine can participate in driving the wheels; at the same time, it can obtain the current generating torque of the P1 motor when the vehicle meets the preset enabling conditions as the initial generating torque for subsequent torque transfer control.

[0116] Optionally, the controller can obtain the initial generated torque in the following way: When the vehicle meets the preset enabling conditions, the motor control unit of motor P1 can collect parameters such as motor current, voltage, and speed, calculate the generated torque value at the current moment through an internal algorithm, and send this value to the controller via the Controller Area Network (CAN) bus. After receiving the torque value, the controller saves it as the initial generated torque.

[0117] S306. Using a preset torque transfer rate, the generator torque of the starter generator is gradually reduced from the initial generator torque to zero, and the generator torque of the drive motor is gradually increased from zero to the initial generator torque, thus completing the switch from series mode to parallel mode.

[0118] In this step, the controller uses a preset torque transfer rate to dynamically distribute the torque of motors P1 and P3. On one hand, the generating torque of motor P1 is gradually reduced from its initial generating torque to zero, causing it to exit the generating state; on the other hand, the generating torque of motor P3 is gradually increased from zero to its initial generating torque, enabling it to take on the generating task.

[0119] At the same time, the crankshaft end of the engine gradually increases the required torque, and the output torque of the P3 motor gradually transitions from positive (driving) to negative (generating electricity), realizing a smooth handover of the driving task to the engine.

[0120] For example, with an initial generated torque of 20 N·m, a torque transfer rate set to 40 N·m / s, and a control cycle of 0.01 s, the generated torque of motor P1 decreases by 0.4 N·m and the generated torque of motor P3 increases by 0.4 N·m in each control cycle. After 50 control cycles (0.5 seconds), the generated torque of motor P1 drops to 0, while the generated torque of motor P3 rises to 20 N·m, completing a seamless transfer of generated torque. During this process, the crankshaft torque demand from the engine gradually increases, gradually taking over the drive task. The drive torque of motor P3 decreases accordingly to 0, and finally, the engine drives the vehicle alone (motor P3 has switched to generator mode and is responsible for generating electricity). The vehicle's power output remains continuous without any jerking or interruption.

[0121] In this embodiment, when the vehicle meets preset enabling conditions, an initial speed difference can be determined and a target speed adjustment curve can be generated. The engine speed is adjusted according to this curve, while a pre-load torque is applied to pre-tighten the clutch. When the speed difference is less than a preset threshold, the clutch torque is adjusted to the target torque, controlling clutch engagement. After engagement, the engine can be requested to output the required torque at the crankshaft end, and the generator torque is gradually reduced to zero using a preset torque transfer rate. Simultaneously, the generator torque of the drive motor is gradually increased from zero to the initial generator torque, completing the switch from series mode to parallel mode. In this process, by pre-planning a smooth target speed trajectory, the engine smoothly adjusts its speed according to this trajectory. Combined with the clutch's stepped pre-load and seamless torque transfer strategy, smooth engine speed adjustment, gradual clutch torque loading, and smooth power transfer between power sources can be achieved, effectively suppressing speed fluctuations, avoiding engagement shocks and power interruptions, and improving the overall smoothness of mode switching.

[0122] Figure 4 This is a schematic diagram illustrating a preset enable condition determination process provided in an embodiment of this application. Please refer to... Figure 4 ,include:

[0123] S401. Is the vehicle powered on and in drive?

[0124] For example, the controller can detect whether the vehicle is powered on and in Drive (D) gear. If the vehicle is not powered on or in Neutral, Reverse, or other non-forward gears, the basic prerequisite for switching to parallel mode is not met. If the above conditions are met (vehicle is powered on and in Drive), step S402 is executed; otherwise, step S408 is executed, prohibiting the issuance of the parallel flag and maintaining the current series mode.

[0125] S402. Is the engine in normal working condition?

[0126] For example, the controller can detect whether there is a shutdown request for the engine. If there is no shutdown request for the engine, step S403 is executed; if there is a shutdown request, step S408 is executed.

[0127] S403. Is the vehicle's current speed greater than or equal to the speed threshold for switching to parallel mode?

[0128] For example, the controller can detect whether the current vehicle speed has reached or exceeded a preset parallel mode speed threshold. If the speed threshold is reached or exceeded, step S404 is executed; if it is not reached, step S408 is executed.

[0129] S404. Is the clutch in a fault-free state?

[0130] For example, the controller can detect whether the clutch is faulty, such as slippage, inability to disengage or engage, or hydraulic system malfunction. If the clutch is fault-free, step S405 is executed; if a fault exists, step S408 is executed.

[0131] S405. Does the discharge power of the power battery exceed the preset discharge power threshold?

[0132] For example, the controller can detect whether the current available discharge power of the power battery is greater than a preset discharge power threshold of 20kW. If it is greater than the threshold, step S406 is executed; if it is less than or equal to the threshold, step S408 is executed.

[0133] S406. Is the current engine speed within the preset speed range?

[0134] For example, the controller can detect whether the current engine speed falls within a preset speed range (e.g., 1000 rpm to 4000 rpm). If the current engine speed is within this range, step S407 is executed; if the current engine speed is below the lower limit or above the upper limit, step S408 is executed.

[0135] S407, Speed ​​control flag is on, clutch engagement begins.

[0136] The controller can activate the speed control flag of Engine Speed ​​Control (ESC), acquire the target speed adjustment curve of the engine, adjust the engine speed according to the curve, and allow the clutch to perform engagement operation, so that the vehicle starts to switch from series mode to parallel mode.

[0137] S408, speed control flag is off, maintaining the current series mode.

[0138] The controller can turn off the ESC speed control flag, prohibit the clutch from engaging, and maintain the vehicle in the current series mode without performing mode switching.

[0139] The preset enable condition judgment process provided in this application embodiment detects and verifies multiple conditions, including vehicle power-on status and gear position, engine operating status, current vehicle speed, clutch status, power battery discharge power, and current engine speed, ensuring that the speed adjustment flag is activated and the clutch engagement operation is allowed only when all conditions are met. This judgment mechanism effectively avoids problems such as mode switching failure, clutch impact, or power interruption caused by abnormal vehicle status or unsuitable operating conditions, significantly improving the safety and reliability of mode switching. It provides a guarantee for subsequent smooth engine speed adjustment, smooth clutch engagement, and seamless torque transfer, thereby further improving the smoothness of speed adjustment and driving comfort throughout the entire process of switching from series mode to parallel mode.

[0140] Figure 5 This is a schematic diagram of the speed regulation process provided in an embodiment of this application. Please refer to... Figure 5 ,include:

[0141] S501, Speed ​​control flag is on.

[0142] After the controller detects that the vehicle meets the preset enabling conditions, it can activate the ESC speed control flag and begin to execute speed control.

[0143] S502, Calculate and lock the initial speed difference.

[0144] Specifically, the controller can obtain the current engine speed and the actual speed of the clutch output shaft, calculate the difference between the two as the initial speed difference, and lock this value for subsequent generation of the target speed adjustment curve.

[0145] S503. Input the preset speed adjustment time, and calculate the remaining speed difference at each time point according to the speed difference smooth transition function.

[0146] For example, the controller divides the speed adjustment time into multiple consecutive time points according to the preset speed adjustment time (such as 3 seconds), and uses the speed difference smooth transition function to calculate the remaining speed difference corresponding to each time point, so that the speed difference gradually decreases from the initial value to zero.

[0147] S504. Generate the target speed adjustment curve based on the remaining speed difference at each time point.

[0148] Specifically, the controller can generate a target speed adjustment curve that smoothly transitions from the current engine speed to the actual speed of the clutch output shaft based on the remaining speed difference at each time point, in order to plan the trajectory of engine speed change.

[0149] S505: Based on the current engine speed, calculate the pre-build-up torque using a proportional-integral control algorithm.

[0150] For example, the controller can obtain the P-term torque component based on the derivative of the current engine speed, the moment of inertia, and the P-term correction coefficient, and obtain the upper and lower limits of the I-term torque by looking up a table based on the current engine speed. After integral adjustment, the I-term torque component is obtained. The P-term and I-term torque components are superimposed to obtain the pre-built torque.

[0151] Among them, the derivative of the current engine speed can be obtained by differential calculation of the signal collected by the speed sensor; the moment of inertia is an inherent parameter of the rotating parts of the engine, which can be pre-calibrated according to the engine model; the P-term correction coefficient and the mapping relationship on which the I-term lookup table is based can both be pre-determined through bench testing or actual vehicle calibration and stored in the controller.

[0152] S506. Apply a pre-built torque to the clutch with a preset slope as a constraint condition.

[0153] Specifically, during the application of pre-loaded torque, the controller can use a preset slope as a constraint condition to limit the rate of torque change to no more than the slope, so that the clutch torque rises smoothly and the clutch is in a pre-loaded state.

[0154] S507. During speed adjustment, determine whether the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than 50 rpm.

[0155] The controller can continuously monitor the speed difference between the current engine speed and the actual speed of the clutch output shaft. If the speed difference is less than or equal to 50 rpm, it indicates that the engine speed and the clutch output shaft speed are basically synchronized, and S508 can be executed; otherwise, S509 is executed to continue speed adjustment.

[0156] S508, Set the speed regulation completion flag.

[0157] When the speed difference meets the conditions, the controller sets the speed regulation completion flag, indicating that the speed regulation process has been completed and the clutch is allowed to perform a full engagement operation.

[0158] S509, continue adjusting the speed.

[0159] If the speed difference does not meet the condition, return to S507 to continue the speed adjustment operation until the speed difference reaches less than or equal to 50 rpm.

[0160] S510 controls the engine to output the required torque at the crankshaft end, and the drive motor disengages from the drive torque.

[0161] Specifically, after the clutch is fully engaged, the controller requests the engine to output the required torque from the crankshaft end, so that the engine can participate in driving the wheels; at the same time, the drive motor gradually withdraws the driving torque (switches to power generation mode) and hands over the driving task to the engine.

[0162] S511, the generating torque of the integrated generator is transferred to the drive motor.

[0163] Specifically, the controller can use a preset torque transfer rate to gradually reduce the generating torque of motor P1 from the initial generating torque to zero, and gradually increase the generating torque of motor P3 from zero to the initial generating torque.

[0164] The speed regulation process provided in this application embodiment locks the initial speed difference and generates a target speed adjustment curve based on a smooth transition function, enabling the engine speed to change smoothly along a preset trajectory. During speed regulation, a pre-loaded torque is applied simultaneously, placing the clutch in a pre-engaged state, and the timing of full clutch engagement is determined by a speed difference threshold. After engagement, the complete switching from series to parallel mode is achieved through the loading of engine drive torque, the unloading of motor drive torque, and the smooth transfer of power generation tasks between different motors. This speed control method effectively suppresses speed fluctuations, eliminates engagement shocks, and ensures the continuity of power output, thereby significantly improving the smoothness and driving comfort during mode switching.

[0165] Figure 6 The control timing diagram for switching from series mode to parallel mode provided in the embodiments of this application is shown below. Figure 6 This timing diagram illustrates the temporal changes in engine speed, clutch output shaft speed, target speed adjustment curves, and clutch status during the vehicle's transition from series mode to parallel mode.

[0166] In the speed change curve, the initial engine speed is higher than the clutch output shaft speed. When the speed adjustment flag is activated, the engine speed smoothly decreases along the target speed adjustment curve, gradually approaching the clutch output shaft speed. During the speed adjustment process, the clutch remains disengaged, and the speed difference between the engine speed and the clutch output shaft speed gradually decreases. When the speed difference is less than a preset threshold (e.g., 50 rpm), the clutch begins to engage, and the engine speed and the clutch output shaft speed are essentially synchronized.

[0167] In the torque variation curve, at the beginning of the speed regulation phase, the clutch applies a pre-load torque, putting it in a pre-compression state. At this time, the actual torque transmitted by the clutch is low (virtually no drive torque is transmitted). When the speed difference meets the engagement condition, the actual torque transmitted by the clutch gradually increases from the pre-load torque to the target torque, achieving full clutch engagement. Simultaneously, the engine output torque gradually increases, and the P3 motor output torque gradually decreases from positive (driving) and transitions to negative (generating power), completing a smooth handover between driving and power generation tasks. The generating torque of the P1 motor gradually decreases to zero, while the generating torque of the P3 motor gradually increases from zero to its initial generating torque, achieving a seamless transfer of power generation tasks.

[0168] By using the smooth speed regulation curve of the target speed, the clutch timing coordination driven by the speed difference, and the coordinated control of torque from multiple power sources, speed overshoot and oscillation can be effectively avoided, clutch engagement shock can be eliminated, a smooth transition from series mode to parallel mode can be achieved, and the smoothness of mode switching can be improved.

[0169] Figure 7This is a schematic diagram of the vehicle drive mode switching control device provided in an embodiment of this application. Please refer to... Figure 7 The vehicle drive mode switching control device 10 includes:

[0170] The first processing module 11 is used to acquire the target speed adjustment curve of the engine when the vehicle meets the preset enabling conditions. The preset enabling conditions are used to represent the operating conditions required for the vehicle to switch from series mode to parallel mode.

[0171] The second processing module 12 is used to adjust the current speed of the engine according to the target speed adjustment curve, and control the clutch to perform an engagement operation when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold.

[0172] The control module 13 is used to control the engine to output the required torque at the crankshaft end after the clutch is engaged, and to transfer the generated torque of the starter generator to the drive motor, thus completing the switch from series mode to parallel mode.

[0173] The vehicle drive mode switching control device provided in this application embodiment can execute the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar, and will not be described again here.

[0174] In one possible implementation, the first processing module 11 is specifically used for:

[0175] When the vehicle meets the preset enabling conditions, determine the initial speed difference between the current engine speed and the actual speed of the clutch output shaft;

[0176] According to the preset speed adjustment time, the initial speed difference is smoothly transitioned to the preset speed difference to generate the target speed adjustment curve.

[0177] In one possible implementation, the first processing module 11 is specifically used for:

[0178] Divide the preset speed adjustment time into multiple consecutive time points;

[0179] Based on the speed difference smooth transition function and the initial speed difference, the remaining speed difference corresponding to each time point is calculated, and the remaining speed difference corresponding to the last time point among multiple consecutive time points is the preset speed difference;

[0180] A target speed adjustment curve is generated based on the remaining speed difference at each time point.

[0181] In one possible implementation, the second processing module 12 is specifically used for:

[0182] When adjusting the current engine speed according to the target speed adjustment curve, a pre-load torque is applied to the clutch to put the clutch in a pre-engaged state.

[0183] When the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than a preset threshold, the pre-built torque is adjusted to the target torque to control clutch engagement.

[0184] In one possible implementation, the second processing module 12 is specifically used for:

[0185] Based on the current engine speed, the pre-build-up torque is calculated using a proportional-integral control algorithm;

[0186] A pre-set pressure torque is applied to the clutch using a preset slope as a constraint condition.

[0187] In one possible implementation, the control module 13 is specifically used for:

[0188] Obtain the initial generating torque of the integrated generator when it starts. The initial generating torque is the current generating torque of the integrated generator when the vehicle meets the preset enabling conditions.

[0189] Using a preset torque transfer rate, the generator torque of the starter generator is gradually reduced from the initial generator torque to zero, while the generator torque of the drive motor is gradually increased from zero to the initial generator torque.

[0190] In one possible implementation, the preset enable condition includes at least one of the following:

[0191] The vehicle is powered on and in drive;

[0192] The engine is in normal operating condition, and the current engine speed is within the preset speed range;

[0193] The vehicle's current speed is greater than or equal to the speed threshold for switching to parallel mode;

[0194] The clutch is in a fault-free state;

[0195] The discharge power of the power battery is greater than the preset discharge power threshold.

[0196] The vehicle drive mode switching control device provided in this application embodiment can execute the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar, and will not be described again here.

[0197] Figure 8 This is a schematic diagram of the controller provided in an embodiment of this application. Please refer to... Figure 8The controller 20 provided in this embodiment can be a vehicle controller, an autonomous driving domain controller, or a central domain controller in a vehicle, or it can be a dedicated controller that is set up independently. This application does not limit this.

[0198] The controller 20 may include at least one processor 21 and a memory 22. Optionally, the controller 20 may also include a communication component 24. The processor 21, the memory 22, and the communication component 24 are connected via a bus 23.

[0199] In a specific implementation, at least one processor 21 executes computer execution instructions stored in memory 22, causing at least one processor 21 to perform the above-described method.

[0200] The specific implementation process of processor 21 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0201] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0202] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0203] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0204] This application provides a vehicle, including a vehicle body and... Figure 8 The controller shown is used to implement the vehicle drive mode switching control method provided in the above method embodiments.

[0205] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described vehicle drive mode switching control method.

[0206] This application also provides a computer-readable storage medium storing computer-executable instructions. When the processor executes the computer-executable instructions, the above-described vehicle drive mode switching control method is implemented.

[0207] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0208] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0209] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0210] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0211] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0212] If a function 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 invention, or the part that contributes to the prior art, or a 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 of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0213] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0214] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A control method for switching vehicle drive modes, characterized in that, include: When the vehicle meets the preset enabling conditions, the target speed adjustment curve of the engine is obtained. The preset enabling conditions are used to represent the operating conditions required for the vehicle to switch from series mode to parallel mode. The engine's current speed is adjusted according to the target speed adjustment curve, and when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold, the clutch is controlled to perform an engagement operation. After the clutch is engaged, the engine outputs the required torque at the crankshaft end, and the generated torque of the generator is transferred to the drive motor, completing the switch from the series mode to the parallel mode.

2. The method according to claim 1, characterized in that, The step of acquiring the target engine speed adjustment curve when the vehicle meets preset enabling conditions includes: When the vehicle meets the preset enabling conditions, the initial speed difference between the current speed of the engine and the actual speed of the clutch output shaft is determined; According to the preset speed adjustment time, the initial speed difference is smoothly transitioned to the preset speed difference to generate the target speed adjustment curve.

3. The method according to claim 2, characterized in that, The step of smoothly transitioning the initial speed difference to a preset speed difference according to a preset speed adjustment time, and generating the target speed adjustment curve, includes: The preset speed adjustment time is divided into multiple consecutive time points; Based on the speed difference smooth transition function and the initial speed difference, the remaining speed difference corresponding to each time point is calculated, and the remaining speed difference corresponding to the last time point among the multiple consecutive time points is the preset speed difference; The target speed adjustment curve is generated based on the remaining speed difference corresponding to each time point.

4. The method according to any one of claims 1-3, characterized in that, The step of adjusting the current engine speed according to the target speed adjustment curve, and controlling the clutch to perform an engagement operation when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold, includes: When adjusting the current engine speed according to the target speed adjustment curve, a pre-load torque is applied to the clutch to put the clutch in a pre-engaged state; When the speed difference between the current engine speed and the actual speed of the clutch output shaft is less than a preset threshold, the pre-load torque is adjusted to the target torque to control the clutch engagement.

5. The method according to claim 4, characterized in that, Applying a pre-load torque to the clutch includes: The pre-build-up torque is calculated based on the current engine speed using a proportional-integral control algorithm. The pre-built torque is applied to the clutch with a preset slope as a constraint condition.

6. The method according to any one of claims 1-3, characterized in that, The process of transferring the generating torque of the integrated generator to the drive motor includes: The initial power generation torque of the starter generator is obtained, wherein the initial power generation torque is the current power generation torque of the starter generator when the vehicle meets the preset enabling conditions; Using a preset torque transfer rate, the generating torque of the integrated starter generator is gradually reduced from the initial generating torque to zero, while the generating torque of the drive motor is gradually increased from zero to the initial generating torque.

7. The method according to any one of claims 1-3, characterized in that, The preset enabling condition includes at least one of the following: The vehicle is powered on and in forward gear; The engine is in normal operating condition, and the current speed of the engine is within the preset speed range; The vehicle's current speed is greater than or equal to the speed threshold for switching to the parallel mode. The clutch is in a fault-free state; The discharge power of the power battery is greater than the preset discharge power threshold.

8. A control device for switching vehicle drive modes, characterized in that, include: The first processing module is used to acquire the target speed adjustment curve of the engine when the vehicle meets the preset enabling conditions. The preset enabling conditions are used to represent the operating conditions required for the vehicle to switch from series mode to parallel mode. The second processing module is used to adjust the current speed of the engine according to the target speed adjustment curve, and control the clutch to perform an engagement operation when the speed difference between the current speed and the actual speed of the clutch output shaft is less than a preset threshold. The control module is used to control the engine to output the required torque at the crankshaft end after the clutch is engaged, and to transfer the generated torque of the generator to the drive motor, thereby completing the switch from the series mode to the parallel mode.

9. A controller, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-7.

10. A vehicle, characterized in that, include: The vehicle body, and the controller as described in claim 9.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-7.

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