Vehicle clutch control method and vehicle

Abstract

This application provides a vehicle clutch control method and vehicle, belonging to the field of hybrid vehicle technology. The method includes: when the switching command is a clutch engagement command, adjusting the engine speed based on a comparison between the vehicle's current speed and a preset speed threshold, and controlling clutch engagement after the speed adjustment is completed; when the switching command is a clutch disengagement command, determining the urgency of the clutch disengagement command and acquiring engine characteristic parameters, obtaining a target torque reduction rate based on the urgency and characteristic parameters, and determining the engine torque reduction ratio and the generator negative torque ratio based on the engine speed and current road gradient; and controlling clutch disengagement based on the target torque reduction rate, the engine torque reduction ratio, and the generator negative torque ratio. The method provided by this invention ensures rapid response during emergency clutch disengagement and smooth transition in non-emergency conditions.

Description

Technical Field

[0001] This invention belongs to the field of hybrid vehicle technology, specifically relating to a vehicle clutch control method and a vehicle. Background Technology

[0002] Hybrid electric vehicles rely on electromagnetic clutches to switch power between the engine and the electric motor. Closed-loop current control of the electromagnetic clutch is crucial for ensuring its rapid response and smooth engagement. However, electromagnetic clutches exhibit strong nonlinear and time-varying characteristics, making it difficult to achieve precise current tracking under all operating conditions. This can easily lead to engagement shocks or response delays, affecting driving smoothness and system stability. Summary of the Invention

[0003] In view of the above problems, embodiments of this application provide a vehicle clutch control method and a vehicle to overcome or at least partially solve the above problems.

[0004] In a first aspect, this application provides a vehicle clutch control method, comprising: a vehicle main controller issuing a switching command; when the switching command is a clutch engagement command, adjusting the engine speed based on a comparison between the vehicle's current speed and a preset speed threshold, and controlling the clutch to engage after the speed adjustment is completed; when the switching command is a clutch disengagement command, determining the urgency of the clutch disengagement command and acquiring characteristic parameters of the engine, the characteristic parameters including engine speed and load, adjusting a preset base torque reduction rate based on the urgency and the characteristic parameters to obtain a target torque reduction rate, and determining the engine torque reduction ratio and the generator negative torque ratio based on the engine speed and the current road gradient; controlling the clutch to disengage based on the target torque reduction rate, the engine torque reduction ratio, and the generator negative torque ratio; wherein the urgency of the clutch disengagement command is negatively correlated with the time required for clutch disengagement, and the sum of the engine torque reduction ratio and the generator negative torque ratio equals 1.

[0005] In some embodiments, adjusting a preset base torque reduction rate based on the urgency level and the characteristic parameters to obtain a target torque reduction rate includes: determining an urgency coefficient based on the urgency level of the clutch disengagement command; wherein the urgency coefficient is positively correlated with the urgency level; determining a speed coefficient based on the current engine speed and multiple different speed ranges; wherein different speed ranges correspond to different speed coefficients; determining a load coefficient based on the current load of the engine; wherein the load coefficient is positively correlated with the load magnitude; and determining the torque reduction rate based on the urgency coefficient, the speed coefficient, and the load coefficient, relative to the preset base torque reduction rate.

[0006] In some embodiments, determining the engine torque reduction ratio and the generator negative torque ratio based on the engine speed and the current road slope includes: determining the current road slope type based on the current road slope; determining the target speed range where the engine speed is located based on the engine speed and a plurality of preset speed ranges; and determining the engine torque reduction ratio and the generator negative torque ratio according to the current road slope type and the target speed range.

[0007] In some embodiments, determining the engine torque reduction ratio and the generator negative torque ratio based on the current road slope type and the target speed range includes: when the target speed range is a first speed range, if the current road slope type is flat or downhill, determining the engine torque reduction ratio as a first torque reduction ratio and the generator negative torque ratio as a first negative torque ratio; if the current road slope type is uphill, determining the engine torque reduction ratio as a second torque reduction ratio and the generator negative torque ratio as a second negative torque ratio, wherein the first torque reduction ratio is greater than the second torque reduction ratio, and the engine torque reduction ratio is greater than the generator negative torque ratio.

[0008] In some embodiments, determining the engine torque reduction ratio and the generator negative torque ratio based on the current road slope type and the target speed range further includes: when the target speed range is a second speed range, determining the engine torque reduction ratio and the generator negative torque ratio based on the current road slope type, the ratio between the speed and the upper limit of the second speed range, and a preset ratio correction factor; when the target speed range is a third speed range, if the current road slope type is flat or uphill, determining the engine torque reduction ratio as the third torque reduction ratio and the generator negative torque ratio as the third negative torque ratio; if the current road slope type is downhill, determining the engine torque reduction ratio as the fourth torque reduction ratio and the generator negative torque ratio as the fourth negative torque ratio; the third negative torque ratio is greater than the fourth negative torque ratio, and the engine torque reduction ratio is less than the generator negative torque ratio; wherein, the speed in the third speed range is greater than the speed in the second speed range, and the speed in the second speed range is greater than the speed in the first speed range.

[0009] In some embodiments, controlling the clutch to disengage based on the target torque reduction rate, the engine torque reduction ratio, and the generator negative torque ratio includes: obtaining a required torque; reducing the engine torque at the input end of the clutch to a first target torque based on the required torque, the target torque reduction rate, and the engine torque reduction ratio, and increasing the generator negative torque at the input end of the clutch to a second target torque; wherein the first target torque is the product of the required torque and the engine torque reduction ratio, and the second target torque is the product of the required torque and the generator negative torque ratio.

[0010] In some embodiments, before the vehicle main controller issues the switching command, the method further includes: The system acquires the vehicle's current speed, required torque, and remaining battery power; when the required torque is greater than a preset required torque and the remaining battery power is greater than a preset power threshold, it acquires the clutch engagement command; when the current speed is less than a preset speed, and the required torque is less than or equal to the preset required torque or the remaining battery power is less than or equal to the preset power threshold, it acquires the clutch disengagement command.

[0011] In some embodiments, adjusting the engine speed based on a comparison between the vehicle's current speed and a preset speed threshold, and controlling the clutch to engage after the speed adjustment is completed, includes: when the current vehicle speed is less than the preset speed threshold, obtaining a first threshold and controlling the speed difference between the input and output ends of the clutch to be less than the first threshold; wherein the first threshold represents the minimum allowable speed difference under low-speed engagement conditions; when the current vehicle speed is greater than or equal to the preset speed threshold, obtaining a second threshold and controlling the speed difference to be less than the second threshold; wherein the second threshold represents the maximum allowable speed difference under high-speed engagement conditions, and the second threshold is greater than the first threshold.

[0012] In some embodiments, obtaining the first threshold includes: obtaining a first influencing parameter and a second influencing parameter, wherein the first influencing parameter includes electromagnetic coil temperature, supply voltage, clutch friction plate temperature, throttle opening change rate, and vehicle speed, and the second influencing parameter includes remaining battery charge and load; wherein each influencing parameter corresponds to a weight value; a first contribution value is obtained based on the product of the first influencing parameter and the weight value corresponding to each parameter in the first influencing parameter; a second contribution value is obtained based on the product of the second influencing parameter and the weight value corresponding to each parameter in the second influencing parameter; the first contribution value and the second contribution value are superimposed on a base threshold to obtain the first threshold; wherein the base threshold is a speed difference benchmark value calibrated under a preset standard operating condition.

[0013] In some embodiments, before controlling the clutch disengagement based on the torque reduction rate, engine torque reduction ratio, and generator negative torque ratio, the method further includes: if the generator temperature exceeds a temperature threshold or the remaining battery charge is lower than a preset charge threshold, increasing the determined engine torque reduction ratio by a preset ratio and decreasing the determined generator negative torque ratio by the preset ratio.

[0014] In a second aspect of this application, a vehicle is provided, the vehicle including a clutch controller, the clutch controller including a memory and a processor, the processor being configured to execute the method described in the first aspect of this application.

[0015] This embodiment provides a vehicle clutch control method, comprising: the vehicle main controller issuing a switching command; when the switching command is a clutch engagement command, adjusting the engine speed based on a comparison between the vehicle's current speed and a preset speed threshold, and controlling clutch engagement after the speed adjustment is completed. This avoids mechanical shock caused by excessive speed difference without relying on a high-precision current closed loop to compensate for nonlinear torque. When the switching command is a clutch disengagement command, the urgency of the clutch disengagement command is determined and the engine's characteristic parameters, including speed and load, are obtained. Based on the urgency and characteristic parameters, the preset base torque reduction rate is adjusted to obtain the target torque reduction rate. At the same time, based on the engine speed and the current road gradient, the engine torque reduction ratio and the generator negative torque ratio are determined. Then, based on the target torque reduction rate, the engine torque reduction ratio, and the generator negative torque ratio, the clutch disengagement is controlled. This ensures rapid response (shortening time) during emergency disengagement and smooth transition in non-emergency conditions, avoiding delays or jerks caused by a single fixed rate. It fundamentally reduces the dependence on precise clutch torque adjustment, thereby bypassing the control difficulties caused by nonlinear disturbances and improving the system's robustness and driving smoothness. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the steps of a vehicle clutch control method provided in an embodiment of this application. Detailed Implementation

[0018] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0019] Figure 1 This is a flowchart illustrating the steps of a vehicle clutch control method provided in an embodiment of this application. Figure 1 The steps of the vehicle clutch control method are as follows: Step S101: The vehicle main controller issues a switching command; when the switching command is a clutch engagement command, the engine speed is adjusted based on the comparison result between the vehicle's current speed and the preset speed threshold, and after the speed adjustment is completed, the clutch is controlled to engage.

[0020] In this embodiment, the clutch is an electromagnetic clutch, installed between the engine and the drive shaft or the transmission input shaft. The electromagnetic clutch generates a magnetic field by energizing it, attracting or releasing the friction plates or armature, achieving rapid engagement or disengagement between the two rotating components (input shaft and output shaft). During vehicle operation, the system acquires the driver's required torque. The main controller determines whether the clutch needs to engage or disengage based on information such as the current vehicle speed and battery charge. A preset speed threshold characterizes the boundary between low speeds requiring active engine speed matching and higher speeds. For example, if the vehicle is in a low-speed condition (such as starting, following in traffic jams, or reversing), the clutch driven plate (transmission input shaft side) rotates very low or even zero. If the electromagnetic clutch is directly engaged, the engine idle speed (approximately 800 rpm) differs greatly from the driven plate speed, causing a severe impact or even stalling. Therefore, the engine speed needs to be adjusted to lower or raise it to match the driven plate speed. Conversely, if the vehicle is in a medium-to-high-speed condition (such as switching modes while driving), the driven plate already rotates at a higher speed, and the difference between it and the engine idle speed or current speed may be small, or it can be quickly matched with minor adjustments. Sometimes, it is even permissible to engage without adjustment (if the speed difference is within a safe range). Therefore, when engagement is deemed necessary, the main controller will adjust the engine speed based on a comparison between the vehicle's current speed and a preset speed threshold.

[0021] Step S102: When the switching command is a clutch disengagement command, determine the urgency of the clutch disengagement command and obtain the engine's characteristic parameters, including engine speed and load. Adjust the preset base torque reduction rate based on the urgency and characteristic parameters to obtain the target torque reduction rate. Determine the engine torque reduction ratio and the generator negative torque ratio based on the engine speed and the current road slope. Control clutch disengagement based on the target torque reduction rate, the engine torque reduction ratio, and the generator negative torque ratio. The urgency of the clutch disengagement command is negatively correlated with the time required for clutch disengagement, and the sum of the engine torque reduction ratio and the generator negative torque ratio equals 1.

[0022] In this embodiment, when the switching command is a clutch disengagement command, the urgency of the clutch disengagement command is determined and the engine's characteristic parameters are obtained. The urgency of the clutch disengagement command is negatively correlated with the time required for clutch disengagement; the more urgent the urgency, the faster the disengagement is required. For example, during normal gear shifting, the urgency is low, and the disengagement time is ample (e.g., coefficient 1.0); gear shifting while parking on a slope: moderately urgent (uphill coefficient 1.6, downhill 0.8); gear shifting during emergency braking: most urgent (coefficient 2.2, deceleration > 5 m / s²). The higher the urgency, the faster the subsequent target torque reduction rate. Characteristic parameters include load and speed. Load and speed can reflect the engine's current torque output state and rotational kinetic energy, thus affecting how quickly the engine torque needs to be reduced when disengaging the clutch (i.e., the torque reduction rate) to avoid shock, speed spikes, or disengagement failure. The basic torque reduction rate characterizes how quickly the engine torque decreases under standard operating conditions (normal gear shifting, flat road, medium speed, light load). The target torque reduction rate is calculated by adjusting the base torque reduction rate based on factors such as the urgency of the current operating condition, engine speed, and engine load. This yields the actual torque reduction rate required. Therefore, the preset base torque reduction rate can be adjusted based on the urgency and characteristic parameters to obtain the target torque reduction rate. The sum of the engine torque reduction ratio and the generator negative torque ratio equals 1, meaning the sum of the target negative torques of the engine and generator equals the total required braking negative torque. Engine speed determines the operating efficiency range of both the engine and the generator, while road gradient determines the required total braking force and the most stable power distribution. Therefore, the engine torque reduction ratio and the generator negative torque ratio can be determined based on the engine speed and the current road gradient, and then the clutch disengagement can be controlled according to these ratios.

[0023] In some embodiments, adjusting a preset base torque reduction rate based on urgency and characteristic parameters to obtain a target torque reduction rate includes: determining an urgency coefficient based on the urgency of the clutch disengagement command; wherein the urgency coefficient is positively correlated with the urgency; determining a speed coefficient based on the current engine speed and multiple different speed ranges; wherein different speed ranges correspond to different speed coefficients; determining a load coefficient based on the current engine load; wherein the load coefficient is positively correlated with the load magnitude; and determining the torque reduction rate based on the preset base torque reduction rate using the urgency coefficient, speed coefficient, and load coefficient.

[0024] In this embodiment, the preset basic torque reduction rate is adjusted based on the urgency and characteristic parameters to obtain the target torque reduction rate. First, the urgency coefficient is determined based on the urgency of the clutch disengagement command. For example, the urgency coefficient Ke can be 1.0 for normal shifting, 0.8 for hill start shifting (downhill (-15°~0°), 1.0 for flat road (0°), and 1.6 for uphill (0°~15°) (to increase the torque reduction rate to cope with increased load); and 2.2 for emergency braking shifting (e.g., deceleration > 5m / s^2 is emergency braking, which can be calibrated). Based on the current engine speed and multiple different speed ranges, the speed coefficient is determined. Since different speed ranges correspond to different speed coefficients, for example, the engine speed coefficient Ks can be 0.7 (0r / min) for low speed, 1.0 (800~3000r / min) for medium speed, and 1.3 (>3000r / min) for high speed. Alternatively, the load coefficient can be determined based on the current engine load, for example, load coefficient Kl: 1.0 for light load (load < 30%). Rated load), heavy load = 1.4 (load ≥ 30% of rated load). It should be noted that this embodiment does not limit the specific coefficient values; they can be selected based on the actual conditions of the vehicle. Then, based on the urgency coefficient, speed coefficient, and load coefficient, the preset base torque reduction rate is determined, specifically, the base torque reduction rate V_base = 50N. m / s (medium speed, normal shifting, light load condition), target torque reduction rate V_torque=V_base×Ke×Ks×Kl.

[0025] In some embodiments, determining the engine torque reduction ratio and the generator negative torque ratio based on the engine speed and the current road slope includes: determining the current road slope type based on the current road slope; determining the target speed range based on the engine speed and multiple preset speed ranges; and determining the engine torque reduction ratio and the generator negative torque ratio according to the current road slope type and the target speed range.

[0026] In this embodiment, the current road slope can specifically be the angle of the slope. For example, when the road slope angle is between -15° and 0°, it is determined to be a downhill type; when the slope angle is equal to 0°, it is determined to be a flat road type; and when the slope angle is between 0° and 15°, it is determined to be an uphill type. The preset speed range can be specifically divided into a low speed range, a medium speed range, and a high speed range. The low speed range corresponds to a speed of 0~800 r / min, the medium speed range corresponds to 800~3000 r / min, and the high speed range corresponds to a speed greater than 3000 r / min. This embodiment does not limit the values ​​of each speed range; they can be calibrated according to actual needs. The target speed range is the preset speed range corresponding to the current engine speed.

[0027] Then, based on the current engine speed, the target speed range of the engine is determined. Next, based on the current road gradient and the target speed range, the engine torque reduction ratio and the generator negative torque ratio are determined. For example, when the road gradient is downhill and the speed range is high, the engine torque reduction ratio is 0.8, and the generator negative torque ratio is 0.2; when the gradient is flat and the speed range is medium, both are 0.5; when the gradient is uphill and the speed range is low, the engine torque reduction ratio is 0.2, and the generator negative torque ratio is 0.8. In summary, by identifying the gradient (downhill / flat / uphill) and matching the engine speed range, the engine torque reduction ratio and the generator negative torque ratio are determined. This allows engine braking and electric motor braking to work in tandem, avoiding sudden torque changes or shocks. While ensuring smooth separation, it also considers energy recovery efficiency, component safety, and adaptability to different operating conditions. For example, when going downhill at high speed, the engine dominates (0.8), using its own resistance to stabilize the vehicle speed and reducing the jerking sensation caused by frequent adjustments by the electric motor.

[0028] In some embodiments, determining the engine torque reduction ratio and the generator negative torque ratio based on the current road slope type and the target speed range includes: when the target speed range is a first speed range, if the current road slope type is flat or downhill, determining the engine torque reduction ratio as the first torque reduction ratio and the generator negative torque ratio as the first negative torque ratio; if the current road slope type is uphill, determining the engine torque reduction ratio as the second torque reduction ratio and the generator negative torque ratio as the second negative torque ratio, wherein the first torque reduction ratio is greater than the second torque reduction ratio, and the engine torque reduction ratio is greater than the generator negative torque ratio.

[0029] In this embodiment, the first speed range can be a low speed range (e.g., 0~800 r / min). At this low speed, the motor, acting as a generator, may be in an inefficient range, or the battery may be fully charged and unable to charge, thus limiting the motor's proportion. At low speeds, if the engine does not bear any negative torque (i.e., is not dragged), insufficient inertia may cause speed fluctuations or even stalling. Furthermore, when the current road slope is downhill, gravity generates a forward component along the slope, causing the vehicle to accelerate, requiring a larger total braking negative torque to maintain speed or decelerate smoothly. When the current road is flat, there is no additional gravity component, and the total braking demand is moderate. The engine's torque reduction proportion can be determined as the first torque reduction proportion, and the generator's negative torque proportion as the first negative torque proportion. When the current road is uphill, the gravity component is backward, and the vehicle decelerates naturally, requiring less additional braking negative torque. Therefore, a smaller second torque reduction proportion is used for the engine's torque reduction proportion, and a larger second negative torque proportion is used for the generator's negative torque proportion. This avoids excessive braking force leading to excessively rapid speed reduction or poor smoothness, while allowing the motor to bear more negative torque to recover energy. For example: when the road type is flat or downhill, the engine torque decreases by 0.7, and the generator negative torque is 0.3; if the road type is uphill, the engine torque decreases by 0.6, and the generator negative torque is 0.4 (the generator negative torque is still ≤-30N). m, to avoid overload).

[0030] In some embodiments, determining the engine torque reduction ratio and the generator negative torque ratio based on the current road slope type and the target speed range further includes: when the target speed range is a second speed range, determining the engine torque reduction ratio and the generator negative torque ratio based on the current road slope type, the ratio between the speed and the upper limit of the second speed range, and a preset ratio correction factor; when the target speed range is a third speed range, if the current road slope type is flat or uphill, determining the engine torque reduction ratio as the third torque reduction ratio and the generator negative torque ratio as the third negative torque ratio; if the current road slope type is downhill, determining the engine torque reduction ratio as the fourth torque reduction ratio and the generator negative torque ratio as the fourth negative torque ratio; the third negative torque ratio is greater than the fourth negative torque ratio, and the engine torque reduction ratio is less than the generator negative torque ratio; wherein, the speed in the third speed range is greater than the speed in the second speed range, and the speed in the second speed range is greater than the speed in the first speed range.

[0031] In this embodiment, the second speed range is the medium speed range (e.g., 800~3000 r / min), with an upper limit of 3000 r / min. Let the current engine speed be n, then the speed ratio r = n / 3000, where r ranges from 0.267 to 1 (corresponding to 800~3000 r / min). Based on the current road slope type, a basic engine torque reduction ratio η is pre-calibrated (e.g., 0.5 for flat roads, 0.4 for uphill roads, and 0.6 for downhill roads). Combined with a preset ratio correction factor k (k is a calibrable constant, e.g., k = 0.2), the engine torque reduction ratio is determined as η × (1 + k × (r - 0.5)) or η + k × (r - 0.5). For example, when going downhill, η=0.6, k=0.3. If the current speed n=1500r / min, then r=0.5, and the engine's share is 0.6; if n=3000r / min, then r=1, and the engine's share is 0.6+0.3×0.5=0.75; if n=800r / min, then r≈0.267, and the engine's share is 0.6+0.3×(0.267-0.5)=0.53. The generator's negative torque share is always 1 minus the engine's share. Within the second speed range, as the speed increases (r increases), the engine's torque reduction share continuously increases, achieving a smooth transition from the low-speed range to the high-speed range.

[0032] The third speed range is the high speed range (e.g., greater than 3000 r / min). When the engine speed is in the high speed range, if the current road slope is flat or uphill, the engine torque reduction ratio is determined to be 0.4 (third torque reduction ratio), and the generator negative torque ratio is determined to be 0.6 (third negative torque ratio); if the current road slope is downhill, the engine torque reduction ratio is determined to be 0.45 (fourth torque reduction ratio), and the generator negative torque ratio is determined to be 0.55 (fourth negative torque ratio). Since the generator has higher power generation efficiency at high speeds, the generator is given priority to bear the negative torque to recover energy; while a larger total braking force is required when going downhill, the engine torque reduction ratio is appropriately increased (from 0.4 to 0.45), but the generator is still the main generator (0.55) to balance energy recovery and braking stability. It can be seen that the third negative torque ratio (0.6) is greater than the fourth negative torque ratio (0.55), and regardless of whether it is flat, uphill, or downhill, the engine torque reduction ratio (0.4, 0.45) is less than the corresponding generator negative torque ratio (0.6, 0.55). For example, if it is a flat road or uphill, the generator's negative torque is 0.8 and the engine's torque is reduced by 0.2. If it is downhill, the generator's negative torque is 0.7 and the engine's torque is reduced by 0.3 (to suppress drag impact).

[0033] In some embodiments, before controlling clutch disengagement based on torque reduction rate, engine torque reduction ratio, and generator negative torque ratio, the method further includes: increasing the determined engine torque reduction ratio by a preset ratio and decreasing the determined generator negative torque ratio by a preset ratio when the generator temperature exceeds a temperature threshold or the remaining battery charge is lower than a preset charge threshold.

[0034] In this embodiment, before controlling clutch disengagement, it is necessary to obtain the generator temperature and remaining battery charge. For example, if the generator temperature exceeds a temperature threshold (e.g., 120°C) or the remaining battery charge is lower than a preset charge threshold (e.g., 20%), it indicates that the generator is overheated or the battery charge is insufficient to withstand a large negative torque. In this case, the original engine torque reduction ratio is increased by a preset percentage (e.g., 10%), and the generator negative torque ratio is reduced by the same percentage. This allows the engine to bear more braking negative torque, reduces the generator load, and prevents the generator from being damaged due to overheating or the battery from having its lifespan affected by over-discharge. At the same time, it ensures that the total braking torque required for clutch disengagement remains unchanged.

[0035] In some embodiments, controlling clutch disengagement based on a target torque reduction rate, engine torque reduction ratio, and generator negative torque ratio includes: acquiring a required torque; reducing the engine torque at the clutch input end to a first target torque and increasing the generator negative torque at the clutch input end to a second target torque based on the required torque, the target torque reduction rate, and the engine torque reduction ratio; wherein the first target torque is the product of the required torque and the engine torque reduction ratio, and the second target torque is the product of the required torque and the generator negative torque ratio.

[0036] In this embodiment, controlling clutch disengagement requires first obtaining the required torque, which is the total braking negative torque required by the vehicle under the current operating conditions. Based on the required torque, the target torque reduction rate, and the engine torque reduction ratio, the engine torque at the clutch input end is reduced to a first target torque. The first target torque is the product of the required torque and the engine torque reduction ratio. For example, if the required negative torque is -100 N·m, the engine torque reduction ratio is 0.7, and the generator negative torque ratio is 0.3, then the first target torque = -100 × 0.7 = -70 N·m. At this time, the clutch input shaft is reduced to -70 N·m, and the generator negative torque at the clutch input end is increased to a second target torque, which is the product of the required torque and the generator negative torque ratio. Therefore, the second target torque = -100 × 0.3 = -30 N·m. The controller rapidly reduces the engine torque from its current value to -70 N·m at a target torque reduction rate (e.g., -400 N·m / s), while simultaneously increasing the generator negative torque from its current value (e.g., 0 N·m) to -30 N·m. Once the two are synchronized, the sum of the torques at the clutch input (engine side and motor side) is exactly equal to the total required negative torque of -100 N·m, creating shock-free conditions for clutch disengagement.

[0037] In some embodiments, before the vehicle main controller issues a switching command, the method further includes: obtaining the vehicle's current speed, required torque, and remaining battery power; obtaining a clutch engagement command when the required torque is greater than a preset required torque and the remaining battery power is greater than a preset power threshold; and obtaining a clutch disengagement command when the current vehicle speed is less than a preset vehicle speed and the required torque is less than or equal to the preset required torque or the remaining battery power is less than or equal to the preset power threshold.

[0038] In this embodiment, the preset required torque represents the maximum torque output by the engine alone. If the required torque exceeds the preset required torque, the engine and motor need to work together to drive the vehicle. The preset battery charge represents the critical point where the battery charge is low and the engine needs to be started to generate electricity. When the remaining battery charge is lower than the preset charge threshold, the engine needs to drive the motor to generate electricity. At this time, the clutch disengages, decoupling the engine from the wheels to generate electricity at the optimal speed. Therefore, when the required torque is greater than the preset required torque, it indicates that the vehicle needs more power during driving. At this time, the engine alone cannot meet the demand or is in an inefficient range, and the motor needs to intervene as an auxiliary drive. At the same time, the remaining battery charge is greater than the preset charge threshold, indicating that the battery has the ability to provide auxiliary power. Therefore, the main controller issues a clutch engagement command, causing the engine and motor to output torque together to meet the high power demand. The current vehicle speed is less than the preset vehicle speed, indicating that the vehicle is in a low-speed driving state. At this time, if the required torque is less than or equal to the preset required torque, it means that the motor alone can meet the power demand without the need for engine intervention. Therefore, the clutch can be disengaged to switch to pure electric mode and reduce fuel consumption. If the remaining battery power is less than or equal to the preset power threshold, it means that the battery power is low and the engine needs to be started to drive the motor to generate electricity (range extender mode). At this time, disengaging the clutch can decouple the engine from the wheels, allowing the engine to drive the generator to generate electricity, while the motor independently drives the wheels, thereby achieving efficient power generation and smooth driving.

[0039] In some embodiments, adjusting the engine speed based on a comparison between the vehicle's current speed and a preset speed threshold, and controlling the clutch engagement after speed adjustment, includes: when the current speed is less than the preset speed threshold, obtaining a first threshold and controlling the speed difference between the clutch input and output terminals to be less than the first threshold; wherein the first threshold represents the minimum allowable speed difference under low-speed engagement conditions; when the current speed is greater than or equal to the preset speed threshold, obtaining a second threshold and controlling the speed difference to be less than the second threshold; wherein the second threshold represents the maximum allowable speed difference under high-speed engagement conditions, and the second threshold is greater than the first threshold.

[0040] In this embodiment, when the vehicle starts or follows another vehicle in congested traffic, the vehicle speed is low, the rotational inertia of the transmission system (gearbox, half-shafts, wheels) is small, and the overall vehicle kinetic energy is low. If the speed difference between the input and output ends is large when the clutch engages, it will produce obvious jerking, engine lurching, or even stalling, resulting in a very poor driving experience. The preset vehicle speed threshold represents the dividing point between low speeds requiring fine-tuning and high speeds where direct engagement is possible. When the vehicle speed is below the preset speed threshold, the speed difference between the clutch engagement and the speed difference must be strictly controlled (a smaller threshold). When the vehicle speed is above or equal to the preset speed threshold, a larger speed difference is allowed to improve response speed. When the current vehicle speed is less than the preset speed threshold, a first threshold is obtained, and the speed difference between the input and output ends of the clutch is controlled to be less than the first threshold before the clutch engages.

[0041] The vehicle is already at a high speed, the transmission system has a large moment of inertia, and the vehicle has a large kinetic energy. Due to the inertial filtering effect of the system itself at high speeds, even if there is a certain speed difference (e.g., 100 rpm), the impact during engagement will be absorbed by inertia and will not be easily noticed by the driver. At high speeds, the inertia is large and the impact is diluted, so a slightly larger speed difference is allowed in exchange for response speed. When the current vehicle speed is greater than or equal to the preset vehicle speed threshold, the speed difference can be controlled to be less than the second threshold, and the second threshold can be greater than the first threshold. During the process of controlling clutch engagement, the engine speed adjustment waiting time can be reduced, and clutch engagement can be completed more quickly.

[0042] In some embodiments, obtaining the first threshold includes: obtaining a first influencing parameter and a second influencing parameter, wherein the first influencing parameter includes electromagnetic coil temperature, supply voltage, clutch friction plate temperature, throttle opening change rate, and vehicle speed, and the second influencing parameter includes remaining battery charge and load; wherein each influencing parameter corresponds to a weight value; a first contribution value is obtained based on the product of the first influencing parameter and the weight values ​​corresponding to each parameter in the first influencing parameter; a second contribution value is obtained based on the product of the weight values ​​corresponding to each parameter in the second influencing parameter and the second influencing parameter; and the first contribution value and the second contribution value are superimposed on a base threshold to obtain the first threshold; wherein the base threshold is a speed difference reference value calibrated under a preset standard operating condition.

[0043] In this embodiment, to avoid slippage due to excessive speed difference even when the clutch is engaged, or impact due to insufficient suction even when the speed difference is too small, the magnetic clutch's suction power decreases with voltage fluctuations and temperature increases (the suction power decreases by 8%~12% for every 20°C increase in temperature). An unreasonable first threshold setting can easily lead to slippage at high temperatures or excessive suction causing impact at low temperatures. Therefore, the influence of multiple parameters, such as electromagnetic coil temperature, supply voltage, and vehicle operating conditions, will be comprehensively considered to obtain a first influencing parameter and a second influencing parameter. The first influencing parameter includes electromagnetic coil temperature, supply voltage, clutch friction plate temperature, throttle opening rate of change, and vehicle speed. The second influencing parameter includes remaining battery charge and load. Each influencing parameter corresponds to a weight value; see Table 1 for details.

[0044] Table 1 is a weighting table for influencing parameters provided in this embodiment.

[0045]

[0046] As shown in Table 1, the first contribution value is obtained by multiplying the first influencing parameter and the weight values ​​of each parameter within the first influencing parameter. The second contribution value is obtained by multiplying the second influencing parameter and the weight values ​​of each parameter within the second influencing parameter. The first and second contribution values ​​are then superimposed with the base threshold to obtain the first threshold. The basic correlation between the parameters and the threshold is fitted using multiple linear regression to determine the weights of each parameter. A random forest algorithm is then introduced to train a nonlinear mapping model to correct for biases in the base layer (such as the nonlinear growth characteristics of the threshold in the low-temperature range). The output first threshold is: Δn=k1×TO+k2×U+k3×TE+k4×TC-k5×SOC-k6×Load+k7×dθ / dt+C+k8×v, where k1~k8 are parameter weighting coefficients, and C is the basic threshold.

[0047] The method for obtaining the second threshold can also refer to the formula for obtaining the first threshold. In this embodiment, the specific parameter values ​​and weight coefficient values ​​can be set according to actual needs, and this embodiment does not impose any limitations.

[0048] In some embodiments, controlling clutch engagement further includes: outputting a peak current to the clutch coil, determining that clutch engagement is complete when the actual current of the coil reaches a preset proportion of the peak current and continues for a first preset duration, and reducing the peak current to the rated current; controlling the engine to increase torque until the speed difference between the input and output ends of the clutch is less than a third threshold; wherein the third threshold is less than a first threshold; controlling clutch disengagement further includes: outputting zero current to the clutch coil, determining that clutch disengagement is complete when the actual current of the coil is less than a preset shut-off threshold and continues for a second preset duration; and controlling the generator to reverse-drive the engine so that the speed difference between the input and output ends of the clutch is less than the first threshold.

[0049] In this embodiment, controlling clutch engagement can specifically involve the main controller outputting a switching command to the clutch controller after preparing for clutch engagement. The clutch controller first outputs a target current Atarget = A1 (A1 is the peak current in amperes) to the clutch coil. After the coil is energized, a magnetic field is generated, attracting the armature to the rotor. The actual current is greater than A2 (e.g., A2 = A1 * 0.9, set according to the hardware characteristics and actual requirements of the electromagnetic clutch) for a duration of T1 (calibrable, e.g., 50ms). After engagement is complete, the engaged status is fed back to the main controller. The peak current is much greater than the rated current, generating a sufficiently strong initial magnetic force to quickly overcome the gaps and static friction between the friction plates, allowing the clutch to engage rapidly and shortening the response time. A preset ratio (e.g., 90%) + a first preset duration: The judgment is not made only when the current reaches its peak value, as the peak current may only be a short pulse, and the actual current rise has a certain slope. When the current reaches 90% of the peak value and stabilizes for a period of time, it indicates that the magnetic force is sufficient for engagement, and the clutch has transmitted basic torque. This judgment is more reliable and avoids misjudgments due to current fluctuations. Simultaneously, the target current A1 is reduced to A3 (A3 is the rated current, in amps) and maintained, as the electromagnetic clutch relies on a magnetic field to engage the friction plates. Once the clutch is fully engaged, only the holding force needs to be maintained. The magnetic force generated by the rated current is sufficient to handle normal torque transmission, while reducing coil heating and energy consumption, protecting the electromagnetic coil. After the clutch is engaged, the clutch control can also send an engagement signal to the main controller. When the main controller receives the engagement signal from the electromagnetic clutch controller, in order to completely eliminate the impact and achieve smooth power transmission, it is necessary to further compress the speed difference to a smaller range. A small torque is added to the input end of the electromagnetic clutch until the speed difference abs(n1) ≤ threshold 4, where threshold 4 is a minimum value, such as 1 rpm. Entering parallel operation, the engine torque is output according to the drive demand, and the engine torque is slowly increased, using the engine's active output to gradually "flatten" the speed difference until the two ends are almost synchronized. In this way, the driver feels very little jerking.

[0050] When disengaging the clutch, the main controller outputs a disengagement command to the clutch controller. The clutch controller sends a target current Atarget=A4 (A4 is 0A current) to the clutch coil. When the coil is de-energized, the actual current is less than A5 (e.g., A2=A4+0.2, determined by the hardware characteristics and actual needs of the electromagnetic clutch). This current remains less than A5 for a duration T2 (calibrable, e.g., 50ms) until disengagement is complete. The disengaged state is then fed back to the main controller. After the coil is de-energized, the current does not instantly drop to 0 (due to inductance characteristics). A small shutdown threshold (e.g., 0.5A) is set and maintained for a period (e.g., 10ms) to ensure the magnetic force has completely dissipated and the friction plates are fully separated. This prevents residual current from causing partial clutch disengagement and slippage. After disengagement, the engine loses its load, and its speed may drop rapidly (or even stall) or remain at a higher speed due to inertia, while the motor / transmission speed is determined by the vehicle speed. A significant speed difference will occur between the two. Therefore, the generator can be controlled to reverse-drag the engine, keeping the speed difference below the first threshold. When the speed difference is below the first threshold and remains below the preset time, the parallel operation mode is exited, and the engine torque is output according to the generator's needs. The next engagement can be completed quickly without prolonged speed adjustment. This not only recovers some kinetic energy (for power generation) but also prepares the speed for the next clutch engagement. In addition, a current closed-loop control method can be used to achieve precise tracking of the target value of the output current, including: determining the control target as the target current Atarget: when the magnetic circuit is not saturated, the engagement force (i.e., the transmitted torque) of the electromagnetic clutch is approximately proportional to the magnitude of the current in the coil, so the engagement and disengagement of the electromagnetic clutch can be achieved by controlling the coil current. Actual current feedback: current sampling current, using a Hall effect sensor to collect the actual current in real time, and performing RC low-pass filtering (through resistor-capacitor low-pass filtering) and moving average filtering to eliminate or reduce noise. Error calculation: the target current value minus the actual feedback current value. An adaptive PID (Proportional-Integral-Derivative controller) algorithm is implemented in the embedded system: the adaptive PID (adjusting parameters online according to the rate of change of current, proportional-integral-derivative) controller is used to process the error signal and generate a control signal to adjust the working state of the power drive circuit, thereby changing the magnitude of the current in the circuit. To eliminate steady-state error, an integral anti-saturation (Anti-windup) is added, pausing integration when the PWM reaches the limit (0% or 100%). The circuit parameters are then adjusted according to the control signal. The microcontroller outputs a PWM signal through a timer to make the actual current as close as possible to the target current value, thereby controlling the energization and de-energization of the electromagnetic clutch coil. When an abnormally high current is detected, the microcontroller output is shut down; when a sudden current change is detected, active demagnetization (brief reverse voltage) is used to accelerate current decay and prevent damage to the equipment.

[0051] This application also provides a vehicle, which includes a clutch controller. The clutch controller includes a memory and a processor, and the processor is used to execute the method of the first aspect of this application.

[0052] The vehicle provided in this embodiment can determine the torque adjustment rate based on the urgency of the separation command (such as normal gear shift separation / emergency braking separation) and parameters such as the current engine speed during vehicle operation. In emergency conditions, the torque reduction speed is increased to shorten the separation response time, while in normal conditions, the torque reduction speed is reduced to reduce energy loss. Furthermore, based on the collaborative control strategy of engine torque reduction and generator negative torque, a switching threshold and smooth transition algorithm are set to prioritize engine torque reduction at low vehicle speeds (to avoid generator overload) and prioritize generator negative torque at high speeds (to improve torque reduction efficiency).

[0053] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0054] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods and apparatus according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0055] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0056] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0057] The present invention has provided a detailed description of a vehicle clutch control method and a vehicle. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will know that there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A vehicle clutch control method, characterized in that, include: The vehicle's main controller issues a switching command; When the switching command is a clutch engagement command, the engine speed is adjusted based on the comparison result between the vehicle's current speed and a preset speed threshold, and the clutch is engaged after the speed adjustment is completed. When the switching command is a clutch disengagement command, the urgency of the clutch disengagement command is determined and the characteristic parameters of the engine are obtained, including the engine speed and load. Based on the urgency and the characteristic parameters, the preset basic torque reduction rate is adjusted to obtain the target torque reduction rate. Based on the engine speed and the current road gradient, the engine torque reduction ratio and the generator negative torque ratio are determined. Based on the target torque reduction rate, the engine torque reduction ratio, and the generator negative torque ratio, the clutch is controlled to disengage; wherein, the urgency of the clutch disengagement command is negatively correlated with the time required for clutch disengagement, and the sum of the engine torque reduction ratio and the generator negative torque ratio equals 1.

2. The method according to claim 1, characterized in that, Based on the urgency level and the characteristic parameters, the preset base torque reduction rate is adjusted to obtain the target torque reduction rate, including: An urgency coefficient is determined based on the urgency of the clutch disengagement command; wherein the urgency coefficient is positively correlated with the urgency. Based on the current engine speed and multiple different speed ranges, a speed coefficient is determined; wherein, different speed ranges correspond to different speed coefficients. A load factor is determined based on the current load of the engine; wherein the load factor is positively correlated with the load magnitude; The torque reduction rate is determined based on the urgency coefficient, the speed coefficient, and the load coefficient, relative to the preset basic torque reduction rate.

3. The method according to claim 1, characterized in that, The determination of the engine torque reduction ratio and the generator negative torque ratio based on engine speed and current road gradient includes: The current road slope type is determined based on the current road slope. Based on the rotational speed and multiple preset rotational speed ranges, the target rotational speed range in which the rotational speed is located is determined; Based on the current road slope type and target speed range, determine the engine torque reduction ratio and the generator negative torque ratio.

4. The method according to claim 1, characterized in that, Based on the current road gradient type and target speed range, determine the engine torque reduction ratio and the generator negative torque ratio, including: When the target speed range is the first speed range, if the current road slope type is flat or downhill, the engine torque reduction ratio is determined as the first torque reduction ratio, and the generator negative torque ratio is determined as the first negative torque ratio. If the current road slope type is uphill, the engine torque reduction ratio is determined as the second torque reduction ratio, and the generator negative torque ratio is determined as the second negative torque ratio. The first torque reduction ratio is greater than the second torque reduction ratio, and the engine torque reduction ratio is greater than the generator negative torque ratio.

5. The method according to claim 4, characterized in that, Based on the current road slope type and target speed range, determining the engine torque reduction ratio and generator negative torque ratio also includes: When the target speed range is the second speed range, the engine torque reduction ratio and the generator negative torque ratio are determined based on the current road slope type, the ratio between the speed and the upper limit of the second speed range, and the preset ratio correction factor. When the target speed range is the third speed range, if the current road slope type is flat or uphill, the engine torque reduction ratio is determined as the third torque reduction ratio and the generator negative torque ratio is determined as the third negative torque ratio. If the current road slope type is downhill, the engine torque reduction ratio is determined as the fourth torque reduction ratio and the generator negative torque ratio is determined as the fourth negative torque ratio. The third negative torque ratio is greater than the fourth negative torque ratio, and the engine torque reduction ratio is less than the generator negative torque ratio. The rotational speed in the third rotational speed range is greater than that in the second rotational speed range, and the rotational speed in the second rotational speed range is greater than that in the first rotational speed range.

6. The method according to claim 1, characterized in that, Based on the target torque reduction rate, the engine torque reduction ratio, and the generator negative torque ratio, the clutch disengagement is controlled, including: Obtain the required torque; Based on the required torque, the target torque reduction rate, and the engine torque reduction ratio, the engine torque at the input end of the clutch is reduced to a first target torque, and the generator negative torque at the input end of the clutch is increased to a second target torque; wherein, the first target torque is the product of the required torque and the engine torque reduction ratio, and the second target torque is the product of the required torque and the generator negative torque ratio.

7. The method according to claim 1, characterized in that, Before the vehicle main controller issues the switching command, it also includes: Obtain the vehicle's current speed, required torque, and remaining battery power; When the required torque is greater than the preset required torque and the remaining battery charge is greater than the preset charge threshold, the clutch engagement command is obtained; When the current vehicle speed is less than the preset vehicle speed, and the required torque is less than or equal to the preset required torque or the remaining battery charge is less than or equal to the preset charge threshold, the clutch disengagement command is obtained.

8. The method according to claim 1, characterized in that, The step of adjusting the engine speed based on a comparison between the vehicle's current speed and a preset speed threshold, and controlling the clutch to engage after the speed adjustment is complete, includes: When the current vehicle speed is less than the preset vehicle speed threshold, a first threshold is obtained, and the speed difference between the input and output ends of the clutch is controlled to be less than the first threshold; wherein, the first threshold represents the minimum speed difference allowed under low-speed engagement conditions. When the current vehicle speed is greater than or equal to the preset vehicle speed threshold, a second threshold is obtained, and the speed difference is controlled to be less than the second threshold; wherein, the second threshold represents the maximum allowable speed difference under high-speed combined operating conditions, and the second threshold is greater than the first threshold.

9. The method according to claim 8, characterized in that, The process of obtaining the first threshold includes: Obtain a first influencing parameter and a second influencing parameter. The first influencing parameter includes the temperature of the electromagnetic coil, the supply voltage, the temperature of the clutch friction plate, the rate of change of the throttle opening, and the vehicle speed. The second influencing parameter includes the remaining battery charge and the load. Each influencing parameter corresponds to a weight value. The first contribution value is obtained by multiplying the first influence parameter and the weight value corresponding to each parameter in the first influence parameter; The second contribution value is obtained by multiplying the second influence parameter and the weight value corresponding to each parameter in the second influence parameter; The first contribution value and the second contribution value are superimposed with the base threshold to obtain the first threshold; wherein, the base threshold is the speed difference reference value calibrated under preset standard operating conditions.

10. The method according to claim 1, characterized in that, Based on the torque reduction rate, engine torque reduction ratio, and generator negative torque ratio, before controlling the clutch disengagement, the method further includes: If the generator temperature exceeds a temperature threshold or the remaining battery charge is lower than a preset charge threshold, the determined engine torque reduction ratio is increased by a preset ratio, and the determined generator negative torque ratio is decreased by the preset ratio.

11. A vehicle, characterized in that, The vehicle includes a clutch controller, the clutch controller including a memory and a processor, the processor being configured to perform the method according to any one of claims 1-10.

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