Hybrid power vehicle mode switching method and device, vehicle, medium and product

Abstract

The invention relates to the technical field of vehicle control, and discloses a hybrid power vehicle mode switching method and device, a vehicle, a medium and a product, the hybrid power vehicle is divided into two stages before clutch engagement and clutch engagement from series drive to parallel drive, and different control targets of the two stages are used as variables to realize mode switching of the hybrid power vehicle. The method comprises the following steps: establishing state equations in stages by using parameters of a power transmission system, and performing continuous optimization solution by setting optimization targets of the state equations in different stages and connection constraints among the state equations to obtain an optimal torque of a generator in a stage before clutch engagement and an optimal positive pressure change rate of clutch engagement in a clutch engagement stage; by means of the mode switching control method and device, staged control over mode switching is achieved, due to the fact that the optimization target in the clutch engagement stage is that the angular acceleration of the passive end of the clutch reaches the minimum, it is guaranteed that the NVH performance of a transmission system of the hybrid vehicle reaches the optimum in the mode switching process, the comfort of the whole vehicle is improved, and then the use experience of a user is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and particularly to a method, device, vehicle, medium and product for hybrid vehicle mode switching. Background Art

[0002] Hybrid electric vehicles have neither the "range anxiety" faced by pure electric vehicles nor the better fuel economy than fuel vehicles, and have become a hot spot in current automotive research and development. When a hybrid electric vehicle switches from a series drive mode to a parallel drive mode, the engine participates in driving the vehicle through the engagement of a clutch. The switching process and the clutch engagement control are likely to cause problems such as noise, vibration, and harshness (NVH) in the drive system, affecting the comfort of the whole vehicle. Therefore, how to ensure the NVH performance of the drive system during the drive mode switching of hybrid electric vehicles has become an urgent problem to be solved. Summary of the Invention

[0003] In view of this, the present invention provides a method, device, vehicle, medium and product for hybrid vehicle mode switching to solve the problem in the related art that the drive mode switching of hybrid electric vehicles is likely to cause NVH problems in the drive system, thereby affecting the comfort of the whole vehicle.

[0004] In a first aspect, the present invention provides a method for hybrid vehicle mode switching, the method comprising: Obtaining the power transmission system parameters of the hybrid vehicle; Dividing the switching of the hybrid vehicle from series drive to parallel drive into a first stage before clutch engagement and a second stage of clutch engagement, and based on the power transmission system parameters, establishing a first state equation corresponding to the first stage with the generator torque as a variable, and establishing a second state equation corresponding to the second stage with the clutch engagement normal pressure change rate as a variable; Taking the minimum time consumption of the first stage as the optimization objective of the first state equation, taking the minimum angular acceleration of the passive end of the clutch in the second stage as the optimization objective of the second state equation, and establishing a connection constraint between the first state equation and the second state equation based on the angular velocity of the active end of the clutch, and jointly solving the first state equation and the second state equation to obtain the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage; Controlling the process of switching the hybrid vehicle from series drive to parallel drive based on the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage.

[0005] The present invention divides the process of switching a hybrid vehicle from series drive to parallel drive into two stages before and after the clutch engagement. Taking the different control objectives of the two stages as variables, it uses the parameters of the power transmission system to establish state equations in stages. Then, by setting the optimization objectives of the state equations in different stages and the connection constraints between the state equations, continuous optimization is performed to obtain the optimal torque of the generator in the stage before the clutch engagement and the optimal positive pressure change rate of the clutch engagement in the stage of clutch engagement. With this, the staged control of the hybrid vehicle switching from series drive to parallel drive is achieved. Since the optimization objective in the stage of clutch engagement is to minimize the angular acceleration of the passive end of the clutch, the NVH performance of the power transmission system during the mode switching process of the hybrid vehicle is guaranteed to be optimal, improving the comfort of the whole vehicle and thus enhancing the user experience.

[0006] In an alternative embodiment, the control of the process of switching the hybrid vehicle from series drive to parallel drive based on the optimal torque of the generator corresponding to the first stage and the optimal positive pressure change rate of the clutch engagement corresponding to the second stage includes: When the hybrid vehicle is in the first stage of switching from series drive to parallel drive, the generator is controlled based on the optimal torque of the generator corresponding to the first stage; When the hybrid vehicle is in the second stage of switching from series drive to parallel drive, based on the optimal positive pressure change rate of the clutch engagement corresponding to the second stage, the optimal positive pressure of the clutch is determined to control the clutch.

[0007] By controlling the generator according to the optimal torque of the generator obtained through optimization in the stage before the clutch engagement, the present invention can make the angular velocity of the active end of the clutch approach the passive end in the shortest time, thereby shortening the switching time of the whole mode and enhancing the user experience. And by controlling the clutch according to the optimal positive pressure of the clutch obtained through optimization in the stage of clutch engagement, the angular velocity of the passive end of the clutch during the mode switching process is minimized, thus ensuring the NVH performance of the power transmission system and improving the comfort of the whole vehicle.

[0008] In an alternative embodiment, the process of jointly solving the first state equation and the second state equation further includes: Taking the engagement speed difference as a variable, a constraint of the first state equation is established with the difference between the angular velocity of the active end and the angular velocity of the passive end of the clutch corresponding to the end of the first stage not being greater than the engagement speed difference, so as to jointly solve for the target engagement speed difference.

[0009] By taking the engagement speed difference as a variable and using the relationship between the difference between the angular velocity of the clutch driving end and the angular velocity of the clutch driven end and the engagement speed difference as the solution constraint condition of the first state equation, the automatic setting of the engagement speed difference can be realized, avoiding the problem of low mode switching efficiency or poor stability of the hybrid vehicle caused by unreasonable setting of the engagement speed difference due to insufficient manual experience, and further improving the user experience.

[0010] In an alternative embodiment, the method further includes: Obtain the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end during the process of the hybrid vehicle switching from series drive to parallel drive; Determine whether the difference between the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end is greater than the target engagement speed difference; When the difference between the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end is greater than the target engagement speed difference, determine that the hybrid vehicle is in the first stage during the process of switching from series drive to parallel drive.

[0011] By using the target engagement speed difference obtained through continuous optimization solution as the discrimination condition between the pre-clutch engagement stage and the clutch engagement stage, the present invention realizes the accurate division of the pre-clutch engagement stage and the clutch engagement stage. And when the difference between the angular velocity of the clutch driving end and the angular velocity of the driven end is greater than the target engagement speed difference, it is determined that it is in the pre-clutch engagement stage, so as to quickly reach the clutch engagement stage by controlling the engine torque, shorten the mode switching time, and improve the user experience.

[0012] In an alternative embodiment, the method further includes: When the difference between the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end is not greater than the target engagement speed difference, determine that the hybrid vehicle is in the second stage during the process of switching from series drive to parallel drive.

[0013] When the difference between the angular velocity of the clutch driving end and the angular velocity of the driven end is not greater than the target engagement speed difference, the present invention determines that it is in the clutch engagement stage, so as to ensure the NVH performance of the transmission system during the clutch engagement process by controlling the change rate of the clutch engagement positive pressure and improve the vehicle comfort.

[0014] In an alternative embodiment, establishing the connection constraint between the first state equation and the second state equation based on the angular velocity of the clutch driving end includes: Establish the connection constraint between the first state equation and the second state equation with the angular velocity of the clutch driving end at the end of the first stage being equal to the angular velocity of the clutch driving end at the beginning of the second stage.

[0015] In the present invention, by using the equality of the angular velocity of the clutch driving end at the end of the first stage and the angular velocity of the clutch driving end at the start of the second stage as the connection constraint for the two state equations, the situation of discontinuous angular velocity of the clutch driving end during the solution of the state equations is avoided, so that the entire optimized solution result is consistent with the actual vehicle operation, and the practicability of the final mode switching strategy is improved.

[0016] In an alternative embodiment, the process of jointly solving the first state equation and the second state equation further includes: Establishing the constraint of the first state equation with the generator torque being zero corresponding to the start and end of the first stage; Establishing the constraint of the second state equation with the change rate of the clutch engagement positive pressure being zero corresponding to the start and end of the second stage, and the angular velocity of the clutch driving end being equal to the angular velocity of the clutch driven end at the end of the second stage.

[0017] In the present invention, by establishing separate constraint conditions for each state equation, the consistency between the entire optimized solution result and the actual vehicle operation is further improved, and the practicability of the final mode switching strategy and the user experience are enhanced.

[0018] In an alternative embodiment, establishing the first state equation corresponding to the first stage with the generator torque as the variable and the second state equation corresponding to the second stage with the change rate of the clutch engagement positive pressure as the variable based on the power transmission system parameters includes: Respectively establishing the first vehicle dynamics model corresponding to the first stage and the second vehicle dynamics model corresponding to the second stage based on the power transmission system parameters; Based on the first vehicle dynamics model, establishing the first state equation corresponding to the first stage with the generator torque as the variable, and based on the second vehicle dynamics model, establishing the second state equation corresponding to the second stage with the change rate of the clutch engagement positive pressure as the variable.

[0019] In the present invention, by using the power transmission system parameters to establish the vehicle dynamics models corresponding to different stages of clutch engagement, and then using the vehicle dynamics models to establish the state equations for different stages, the solution result of the state equation is further ensured to meet the requirements of vehicle dynamics, and the practicability of the overall switching control scheme is guaranteed.

[0020] In a second aspect, the present invention provides a hybrid vehicle mode switching device, and the device includes: An acquisition module, configured to acquire the power transmission system parameters of the hybrid vehicle; The first processing module is configured to divide the process of switching the hybrid vehicle from series drive to parallel drive into a first stage before clutch engagement and a second stage of clutch engagement, and based on the power transmission system parameters, establish a first state equation corresponding to the first stage with the generator torque as a variable, and establish a second state equation corresponding to the second stage with the clutch engagement normal pressure change rate as a variable; The second processing module is configured to take the minimum time consumption of the first stage as the optimization objective of the first state equation, take the minimum angular acceleration of the clutch passive end in the second stage as the optimization objective of the second state equation, and establish a connection constraint between the first state equation and the second state equation based on the angular velocity of the clutch active end, and jointly solve the first state equation and the second state equation to obtain the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage; The third processing module is configured to control the process of switching the hybrid vehicle from series drive to parallel drive based on the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage.

[0021] In a third aspect, the present invention provides a vehicle, which is a hybrid vehicle, and the vehicle includes: a controller, and the controller includes: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to execute the method described in the first aspect and any one of its optional implementation manners.

[0022] In a fourth aspect, the present invention provides a computer-readable storage medium, on which computer instructions are stored, and the computer instructions are used to cause a computer to execute the method provided in the first aspect or any one of its corresponding implementation manners.

[0023] In a fifth aspect, the present invention provides a computer program product, including computer instructions, and the computer instructions are used to cause a computer to execute the method provided in the first aspect or any one of its corresponding implementation manners.

[0024] Advantages of the present invention: The present invention divides the switching of a hybrid vehicle from series drive to parallel drive into two stages: before the clutch engages and when the clutch engages. Taking the different control objectives of the two stages as variables, state equations are established in stages using the parameters of the power transmission system. Then, by setting the optimization objectives of the state equations in different stages and the connection constraints between the state equations, continuous optimization is solved to obtain the optimal torque of the generator in the stage before the clutch engages and the optimal positive pressure change rate of the clutch engagement in the stage when the clutch engages. Based on this, the staged control of the hybrid vehicle's switching from series drive to parallel drive is achieved. Since the optimization objective in the stage when the clutch engages is to minimize the angular acceleration of the passive end of the clutch, the NVH performance of the power transmission system during the mode switching of the hybrid vehicle is guaranteed to be optimal, improving the comfort of the whole vehicle and thus enhancing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 is a flowchart of a method for switching the mode of a hybrid vehicle according to an embodiment of the present invention; Figure 2 is a schematic diagram of a plug-in hybrid system according to an embodiment of the present invention; Figure 3 is a flowchart of another method for switching the mode of a hybrid vehicle according to an embodiment of the present invention; Figure 4 is a schematic diagram of the main working process of switching the mode of a hybrid vehicle according to an embodiment of the present invention; Figure 5 is a schematic diagram of the optimal torque of the first motor and the optimal positive pressure of the clutch according to an embodiment of the present invention; Figure 6 is a comparison schematic diagram of the angular acceleration of the passive end of the clutch before and after optimizing the mode switching of a hybrid vehicle using an embodiment of the present invention; Figure 7 is a schematic diagram of the structure of a hybrid vehicle mode switching device according to an embodiment of the present invention; Figure 8 is a schematic diagram of the structure of a vehicle controller according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the related art, when a hybrid vehicle switches from a series drive mode to a parallel drive mode, usually the main consideration is the smoothness during the switching process, and the NVH performance during the process from series drive to parallel drive is not considered. It should be noted that in the embodiments of the present invention, the hybrid vehicles mentioned are all plug-in hybrid vehicles, that is, a hybrid system of a vehicle composed of an engine, a generator (also called the first motor), and a drive motor (also called the second motor).

[0029] Based on this, the embodiments of the present invention provide a hybrid vehicle mode switching solution. For the specific process of a plug-in hybrid vehicle switching from series drive to parallel drive, by continuously optimizing the speed regulation process before the clutch engagement and the clutch engagement process in segments, the NVH performance of the transmission system is optimized.

[0030] According to the embodiments of the present invention, an embodiment of a hybrid vehicle mode switching method is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0031] In this embodiment, a hybrid vehicle mode switching method is provided, which can be applied to a controller of a hybrid vehicle, such as control chips like a single-chip microcomputer and an MCU. Figure 1 is a flowchart of the hybrid vehicle mode switching method according to the embodiments of the present invention, as Figure 1 shown, and this process includes the following steps: Step S101, obtain the power transmission system parameters of the hybrid vehicle.

[0032] Specifically, the power transmission system parameters refer to the hardware parameters of the power transmission system involved in the driving process of the hybrid vehicle, and can be specifically obtained from the vehicle parameters of the hybrid vehicle. In the embodiments of the present invention, as Figure 2 shown, the power transmission system parameters at least include: the total inertia of the engine and the first motor , the inertia of the clutch active end , the inertia of the clutch passive end , the inertia of the first gear and radius and the second gear inertia and radius and the third gear inertia and radius and the fourth gear inertia and radius and the second motor inertia and the equivalent inertia of the whole vehicle and the equivalent stiffness of the first motor shaft and equivalent damping and the equivalent stiffness of the first gear shaft and equivalent damping and the meshing stiffness between the first gear and the second gear and meshing damping and the equivalent stiffness of the second gear shaft and equivalent damping and the equivalent stiffness of the third gear shaft and equivalent damping and the meshing stiffness between the third gear and the fourth gear and meshing damping and the equivalent stiffness of the fourth gear shaft and equivalent damping etc. The present invention takes this as an example only and is not limited thereto.

[0033] Step S102: Divide the switching of the hybrid vehicle from series drive to parallel drive into a first stage before the clutch engages and a second stage when the clutch engages, and based on the parameters of the power transmission system, establish a first state equation corresponding to the first stage with the generator torque as a variable, and establish a second state equation corresponding to the second stage with the change rate of the clutch engagement normal pressure as a variable.

[0034] Specifically, since there are two states in the series drive mode of a hybrid vehicle, the first state is that the vehicle is driven by the second motor, the engine drives the first motor to generate electricity, and the power generation speed is higher than the rotational speed of the passive end of the clutch. The engine, the first motor, and the active end of the clutch are coaxially fixedly connected. Therefore, the rotational speed of the active end of the clutch is higher than that of the passive end. The second state is that the vehicle is driven by the second motor while the engine is in a shutdown state. Therefore, the rotational speed of the active end of the clutch is lower than that of the passive end. When switching from series drive to parallel drive, regardless of whether it is the first state or the second state, the control idea for the switch is as follows: before the clutch engages, the rotational speed of the active end of the clutch is controlled by the first motor to approach the rotational speed of the passive end. When the rotational speeds at both ends of the clutch are close, the clutch is then controlled to engage, that is, the control during the clutch engagement phase. Therefore, the switch from series drive to parallel drive of a hybrid vehicle can be divided into a first stage before the clutch engages and a second stage when the clutch engages. In the first stage, it is controlled by the generator torque, that is, the torque of the first motor, and in the second stage, it is controlled by the optimal positive pressure change rate of the clutch engagement. Additionally, it should be noted that the angular velocity mentioned in the embodiments of the present invention is also referred to as rotational speed, which is common knowledge in the art and will not be elaborated further hereinafter.

[0035] Step S103: Taking the minimum time consumption of the first stage as the optimization objective of the first state equation, taking the minimum angular acceleration of the passive end of the clutch in the second stage as the optimization objective of the second state equation, and establishing a connection constraint between the first state equation and the second state equation based on the angular velocity of the active end of the clutch, and jointly solving the first state equation and the second state equation to obtain the optimal torque of the generator corresponding to the first stage and the optimal positive pressure change rate of the clutch engagement corresponding to the second stage.

[0036] Specifically, in order to shorten the time consumption for a hybrid vehicle to switch from series drive to parallel drive, the time consumption during the clutch engagement stage is taken as the optimization objective for this stage. At the same time, in order to ensure the NVH performance of the transmission system during the mode switch, the angular acceleration of the passive end of the clutch is taken as the optimization objective for the clutch engagement stage. By establishing a connection constraint between the two state equations to ensure the continuity of the segmentation process, the NVH performance optimization problem is converted into a state equation solution problem. Thus, through continuous optimization and solution of the state equation, automatic and precise control during the drive mode switch is achieved to ensure the NVH performance of the transmission system.

[0037] Step S104: Based on the optimal torque of the generator corresponding to the first stage and the optimal positive pressure change rate of the first clutch engagement corresponding to the second stage, control the process of the hybrid vehicle switching from series drive to parallel drive.

[0038] Specifically, by using the control parameters obtained through the above steps for optimization, corresponding control is performed on different stages of the whole process of switching the hybrid vehicle from series drive to parallel drive.

[0039] In the present invention, the process of switching the hybrid vehicle from series drive to parallel drive is divided into two stages: before the clutch engages and when the clutch engages. Taking the different control objectives of the two stages as variables, state equations are established in stages using the parameters of the power transmission system. Then, by setting the optimization objectives of the state equations in different stages and the connection constraints between the state equations, continuous optimization is performed to obtain the optimal torque of the generator in the stage before the clutch engages and the optimal positive pressure change rate of the clutch engagement in the stage when the clutch engages. Based on this, staged control of switching the hybrid vehicle from series drive to parallel drive is achieved. Since the optimization objective in the stage when the clutch engages is to minimize the angular acceleration of the passive end of the clutch, the NVH performance of the transmission system during the mode switch of the hybrid vehicle is guaranteed to be optimal, the comfort of the whole vehicle is improved, and thus the user experience is enhanced.

[0040] In this embodiment, a method for switching the mode of a hybrid vehicle is provided, which can be applied to the controller of a hybrid vehicle, such as control chips like a single-chip microcomputer, an MCU, etc. Figure 3 It is a flowchart of the method for switching the mode of a hybrid vehicle according to an embodiment of the present invention, as Figure 3 shown. This process includes the following steps: Step S301, obtain the parameters of the power transmission system of the hybrid vehicle. For detailed content, refer to the relevant description of step S101 as Figure 1 shown, and details will not be elaborated here.

[0041] Step S302, divide the process of switching the hybrid vehicle from series drive to parallel drive into a first stage before the clutch engages and a second stage when the clutch engages. Based on the parameters of the power transmission system, establish a first state equation corresponding to the first stage with the generator torque as the variable, and establish a second state equation corresponding to the second stage with the positive pressure change rate of the clutch engagement as the variable.

[0042] Specifically, the above step S302 includes: Step S3021, respectively establish a first vehicle dynamics model corresponding to the first stage and a second vehicle dynamics model corresponding to the second stage based on the parameters of the power transmission system.

[0043] Among them, the above first vehicle dynamics model is shown in formula (1): (1) Among them, 、 、 are the inertias The corresponding angular displacement, angular velocity, and angular acceleration and are the output torque of the generator and the output torque of the drive motor, respectively.

[0044] The above second vehicle dynamics model is shown in Equation (2): (2) where is the torque transmitted by the clutch, , , respectively represent the clutch friction coefficient, the effective radius of the clutch pressure plate, and the normal pressure acting on the clutch disc.

[0045] Step S3022: Based on the first vehicle dynamics model, establish the first state equation corresponding to the first stage with the generator torque as the variable, and based on the second vehicle dynamics model, establish the second state equation corresponding to the second stage with the clutch engagement positive pressure change rate as the variable.

[0046] Specifically, the above first state equation is shown in Equation (3): (3) where T represents the generator torque, , , , .

[0047] The above second state equation is shown in Equation (4): (4) where , , , , , , , , , , , , , , , , , , , , represents the clutch engagement positive pressure change rate.

[0048] It should be noted that the process of optimizing and solving the above formulas (3) and (4) is a prior art and can be implemented by using the optimization and solution algorithms in the prior art, which will not be elaborated here.

[0049] In the embodiment of the present invention, a vehicle dynamics model corresponding to different stages of clutch engagement is established by using the parameters of the power transmission system, and then the state equations of different stages are established by using the vehicle dynamics model, further ensuring that the solution results of the state equations meet the requirements of vehicle dynamics and ensuring the practicability of the overall switching control scheme.

[0050] Step S303: Taking the minimum time consumption in the first stage as the optimization objective of the first state equation, taking the minimum angular acceleration of the passive end of the clutch in the second stage as the optimization objective of the second state equation, and establishing a connection constraint between the first state equation and the second state equation based on the angular velocity of the active end of the clutch, and jointly solving the first state equation and the second state equation to obtain the optimal torque of the generator corresponding to the first stage and the optimal positive pressure change rate of clutch engagement corresponding to the second stage.

[0051] Specifically, in the first stage, the shorter the time, the better, which can reduce the time of the entire switching process. Therefore, the performance functional, that is, the optimization objective of the first state equation, is shown in formula (5): (5) Wherein, is the optimization objective of the first state equation, is the end time of the first stage.

[0052] During the clutch engagement process in the second stage, a transient impact is generated in the transmission system, which will cause poor NVH performance during the switching process. The NVH performance of the transmission system is mostly indicated by the angular acceleration of the shaft. Therefore, in order to reduce the angular acceleration of the passive end of the clutch during the switching process a performance functional is constructed to optimize and obtain the optimal positive pressure change rate during the clutch engagement process, so as to control the NVH performance during the engagement process. The performance functional, that is, the optimization objective of the second state equation, is shown in formula (6):

[0053] Wherein, is the optimization objective of the second state equation, is the end time of the first stage and also the start time of the second stage, is the end time of the second stage.

[0054] Further, the process of jointly solving the first state equation and the second state equation in step S303 further includes: taking the engagement speed difference as a variable, and establishing a constraint for the first state equation with the difference between the angular velocity of the clutch driving end and the angular velocity of the clutch driven end corresponding to the end of the first stage not being greater than the engagement speed difference, as shown in formula (7), so as to jointly solve for the target engagement speed difference.

[0055] (7) Among them, is the engagement speed difference, is the end time of the first stage, is the angular velocity of the clutch driving end corresponding to the end of the first stage, that is, the angular velocity corresponding to the above-mentioned clutch driving end inertia corresponding angular velocity.

[0056] In the embodiment of the present invention, by taking the engagement speed difference as a variable and using the relationship between the difference between the angular velocity of the clutch driving end and the angular velocity of the clutch driven end and the engagement speed difference as the solution constraint condition of the first state equation, the automatic setting of the engagement speed difference can be realized, avoiding the problem of low mode switching efficiency or poor stability of the hybrid vehicle caused by unreasonable setting of the engagement speed difference due to insufficient manual experience, and further improving the user experience.

[0057] Further, establishing the connection constraint between the first state equation and the second state equation based on the angular velocity of the clutch driving end in step S303 includes: establishing the connection constraint between the first state equation and the second state equation with the angular velocity of the clutch driving end at the end of the first stage being equal to the angular velocity of the clutch driving end at the start of the second stage. Among them, the above connection constraint is as shown in formula (8).

[0058] (8) Among them, is the angular velocity of the clutch driving end corresponding to the end of the first stage, is the angular velocity of the clutch driven end corresponding to the start of the second stage, that is, the angular velocity corresponding to the above-mentioned clutch driven end inertia corresponding angular velocity. It should be noted that since the first stage and the second stage are continuous in time, the end of the first stage and the start of the second stage refer to the same moment. By ensuring that the rotational speed of the clutch driving end at the end of the first stage is the same as the rotational speed at the start of the second stage, the situation of discontinuity during the optimization of the two stages can be avoided.

[0059] In the present invention, by using the equality of the angular velocity of the clutch driving end at the end of the first stage and the angular velocity of the clutch driving end at the start of the second stage as the connection constraint for the two state equations, the situation of discontinuous angular velocity of the clutch driving end during the solution of the state equations is avoided, making the entire optimization solution result consistent with the actual vehicle operation condition and enhancing the practicality of the final mode switching strategy.

[0060] In addition, in practical applications, the process of jointly solving the first state equation and the second state equation in step S303 further includes: Step a1, establishing the constraint of the first state equation with the generator torques corresponding to the start and end of the first stage being zero. Specifically, as shown in formulas (9) and (10).

[0061] (9) (10) Wherein, represents the generator torque corresponding to the start of the first stage, represents the generator torque corresponding to the end of the first stage.

[0062] Step a2, establishing the constraints of the second state equation with the change rate of the clutch engagement positive pressure corresponding to the start and end of the second stage being zero, and the angular velocity of the clutch driving end being equal to the angular velocity of the clutch driven end at the end of the second stage. Specifically, as shown in formulas (11), (12), and (13).

[0063] (11) (12) (13) Wherein, and respectively represent the change rates of the clutch engagement positive pressure corresponding to the start and end of the second stage, and respectively represent the angular velocity of the clutch driving end and the angular velocity of the clutch driven end at the end of the second stage.

[0064] By establishing the separate constraint conditions for each state equation in the embodiments of the present invention, the consistency between the entire optimization solution result and the actual vehicle operation condition is further enhanced, and the practicality of the final mode switching strategy and the user experience are improved.

[0065] Step S304, controlling the process of the hybrid vehicle switching from series drive to parallel drive based on the optimal generator torque corresponding to the first stage and the optimal change rate of the first clutch engagement positive pressure corresponding to the second stage.

[0066] Specifically, the above step S304 includes: Step S3041: When the hybrid vehicle switches from series drive to parallel drive in the first stage, control the generator based on the optimal torque of the generator corresponding to the first stage.

[0067] Step S3042: When the hybrid vehicle switches from series drive to parallel drive in the second stage, determine the optimal positive pressure of the clutch based on the optimal positive pressure change rate of the clutch engagement corresponding to the second stage, and control the clutch.

[0068] In the embodiment of the present invention, by controlling the generator according to the optimal torque of the generator obtained through optimization before the clutch engagement stage, the angular velocity of the active end of the clutch can approach the passive end in the shortest time, thereby shortening the switching time of the entire mode, improving the user experience, and by controlling the clutch according to the optimal positive pressure of the clutch obtained through optimization during the clutch engagement stage, the angular velocity of the passive end of the clutch reaches the minimum during the mode switching process, thus ensuring the NVH performance of the transmission system and improving the comfort of the whole vehicle.

[0069] Furthermore, the embodiment of the present invention further includes the following steps: Step b1: Obtain the current angular velocity of the active end of the clutch and the current angular velocity of the passive end of the clutch during the process of the hybrid vehicle switching from series drive to parallel drive.

[0070] Step b2: Determine whether the difference between the current angular velocity of the active end of the clutch and the current angular velocity of the passive end of the clutch is greater than the target engagement speed difference.

[0071] Step b3: When the difference between the current angular velocity of the active end of the clutch and the current angular velocity of the passive end of the clutch is greater than the target engagement speed difference, determine that the hybrid vehicle is in the first stage when switching from series drive to parallel drive.

[0072] In the embodiment of the present invention, by using the target engagement speed difference obtained through continuous optimization as the discrimination condition for the pre-clutch engagement stage and the clutch engagement stage, the accurate division of the pre-clutch engagement stage and the clutch engagement stage is realized. And when the difference between the angular velocity of the active end of the clutch and the angular velocity of the passive end is greater than the target engagement speed difference, it is determined that it is in the pre-clutch engagement stage, so as to quickly reach the clutch engagement stage by controlling the engine torque, shorten the mode switching time, and improve the user experience.

[0073] Step b4: When the difference between the current angular velocity of the active end of the clutch and the current angular velocity of the passive end of the clutch is not greater than the target engagement speed difference, determine that the hybrid vehicle is in the second stage when switching from series drive to parallel drive.

[0074] When the difference between the angular velocity of the active end and the angular velocity of the passive end of the clutch in the embodiment of the present invention is not greater than the target engagement speed difference, it is determined that the clutch is in the engagement stage, so as to ensure the NVH performance of the transmission system during the clutch engagement process by controlling the change rate of the clutch engagement positive pressure, and improve the vehicle comfort.

[0075] Exemplarily, when the scheme provided by the embodiment of the present invention is used for hybrid vehicle mode switching control, its main working process is as Figure 4 shown, mainly including: S1: Collect vehicle parameters, i.e., the above-mentioned power transmission system parameters.

[0076] S2: Divide the series drive to parallel drive into two stages of "before clutch engagement" and "clutch engagement", and establish vehicle dynamics models for different stages respectively.

[0077] S3: According to the characteristics of different stages and the vehicle dynamics model, establish state equations for different stages, and determine the optimization objectives and constraints for different stages.

[0078] S4: Add connection constraints for the two stages to avoid discontinuity during the two-stage switching.

[0079] S5: Perform piecewise continuous optimization.

[0080] S6: According to the optimization results, change the control strategies of the motor and the clutch during the drive mode switching process to improve the NVH performance of the transmission system.

[0081] The above-mentioned NVH control scheme of the transmission system during the switching process from series drive to parallel drive proposed by the embodiment of the present invention. By optimization, the optimal torque of the generator, i.e., the optimal torque T of the first motor, the engagement speed difference σ, and the optimal positive pressure change rate U of the clutch engagement are obtained. As Figure 5 shown, by using the optimal torque T of the first motor to control the rotation speed of the active end of the clutch in the "before clutch engagement stage" to approach the passive end, and then using the optimal positive pressure of the clutch to control the clutch engagement process in the "clutch engagement stage", the angular velocity of the passive end of the clutch during the switching process is minimized, thereby ensuring the NVH performance of the transmission system.

[0082] Exemplarily, when the above step S6 is used to optimize the control of a hybrid vehicle during the switching from series drive to parallel drive, the comparison result of the angular acceleration change of the passive end of the clutch with that before optimization is as Figure 6 shown. From Figure 6 it can be seen that when the scheme provided by the embodiment of the present invention is used for hybrid vehicle mode switching control, the change amplitude of the angular acceleration of the passive end of the clutch is significantly smaller, thereby significantly improving the NVH performance of the transmission system.

[0083] In this embodiment, a hybrid vehicle mode switching device is also provided. This device is used to implement the above-mentioned embodiments and preferred implementation manners, and those that have been described will not be repeated. As used hereinafter, the term "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0084] An embodiment of the present invention provides a hybrid vehicle mode switching device, as Figure 7 shown, the device includes: An acquisition module 701, configured to acquire power transmission system parameters of the hybrid vehicle; A first processing module 702, configured to divide the switching of the hybrid vehicle from series drive to parallel drive into a first stage before the clutch engages and a second stage when the clutch engages, and based on the power transmission system parameters, establish a first state equation corresponding to the first stage with the generator torque as a variable, and establish a second state equation corresponding to the second stage with the clutch engagement normal pressure change rate as a variable; A second processing module 703, configured to take the minimum time consumption of the first stage as the optimization objective of the first state equation, take the minimum angular acceleration of the passive end of the clutch in the second stage as the optimization objective of the second state equation, and based on the angular velocity of the active end of the clutch, establish a connection constraint between the first state equation and the second state equation, and jointly solve the first state equation and the second state equation to obtain the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage; A third processing module 704, configured to control the process of switching the hybrid vehicle from series drive to parallel drive based on the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage.

[0085] In some alternative implementation manners, the above-mentioned third processing module 704 includes: A first processing unit, configured to control the generator based on the optimal generator torque corresponding to the first stage when the hybrid vehicle is in the first stage of switching from series drive to parallel drive; A second processing unit, configured to determine the optimal clutch normal pressure and control the clutch based on the optimal clutch engagement normal pressure change rate corresponding to the second stage when the hybrid vehicle is in the second stage of switching from series drive to parallel drive.

[0086] In some alternative implementation manners, the above-mentioned second processing module 703 further includes: A third processing unit, configured to use the engagement speed difference as a variable, and establish a constraint of a first state equation with the difference between the angular velocity of the clutch driving end and the angular velocity of the clutch driven end corresponding to the end of the first stage not being greater than the engagement speed difference, so as to jointly solve to obtain the target engagement speed difference.

[0087] In some alternative embodiments, the device further includes: A fourth processing module, configured to obtain the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end during the process of the hybrid vehicle switching from series drive to parallel drive; A fifth processing module, configured to determine whether the difference between the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end is greater than the target engagement speed difference; A sixth processing module, configured to determine that the hybrid vehicle is in the first stage of switching from series drive to parallel drive when the difference between the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end is greater than the target engagement speed difference.

[0088] In some alternative embodiments, the device further includes: A seventh processing module, configured to determine that the hybrid vehicle is in the second stage of switching from series drive to parallel drive when the difference between the current angular velocity of the clutch driving end and the current angular velocity of the clutch driven end is not greater than the target engagement speed difference.

[0089] In some alternative embodiments, the second processing module 703 is specifically configured to establish a connection constraint between the first state equation and the second state equation with the angular velocity of the clutch driving end at the end of the first stage being equal to the angular velocity of the clutch driving end at the start of the second stage.

[0090] In some alternative embodiments, the second processing module 703 further includes: A fourth processing unit, configured to establish a constraint of the first state equation with the generator torque corresponding to the start and end of the first stage being zero; A fifth processing unit, configured to establish a constraint of the second state equation with the change rate of the clutch engagement positive pressure corresponding to the start and end of the second stage being zero, and the angular velocity of the clutch driving end being equal to the angular velocity of the clutch driven end at the end of the second stage.

[0091] In some alternative embodiments, the first processing module 702 includes: A sixth processing unit, configured to respectively establish a first vehicle dynamics model corresponding to the first stage and a second vehicle dynamics model corresponding to the second stage based on the power transmission system parameters; A seventh processing unit is configured to establish a first state equation corresponding to a first stage with the generator torque as a variable based on a first vehicle dynamics model, and establish a second state equation corresponding to a second stage with the clutch engagement normal pressure change rate as a variable based on a second vehicle dynamics model.

[0092] The further function descriptions of the above-mentioned modules and units are the same as those in the corresponding method embodiments described above, and will not be elaborated here.

[0093] An embodiment of the present invention further provides a vehicle, which is a hybrid vehicle. The vehicle includes a controller, as Figure 8 shown. The controller includes one or more processors 10, a memory 20, and interfaces for connecting various components, including a high-speed interface and a low-speed interface. Each component is communicatively connected to each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in the memory or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some alternative embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (such as an array of servers, a set of blade servers, or a multi-processor system). Figure 8 Taking one processor 10 as an example in

[0094] The processor 10 can be a central processing unit, a network processor, or a combination thereof. Among them, the processor 10 can further include a hardware chip. The above-mentioned hardware chip can be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The above-mentioned programmable logic device can be a complex programmable logic device, a field programmable gate array, a generic array logic, or any combination thereof.

[0095] Among them, the memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiments.

[0096] The memory 20 may include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of a computer device presented by a kind of mini-program landing page, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 may optionally include a memory remotely provided with respect to the processor 10, and these remote memories can be connected to the computer device through a network. Examples of the above-mentioned network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0097] The memory 20 may include a volatile memory, for example, a random access memory; the memory may also include a non-volatile memory, for example, a flash memory, a hard disk, or a solid-state drive; the memory 20 may further include a combination of the above-mentioned types of memories.

[0098] The controller further includes a communication interface 30 for the vehicle to communicate with other devices or a communication network.

[0099] Embodiments of the present invention also provide a computer-readable storage medium. The methods according to the embodiments of the present invention can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented as computer code originally stored in a remote storage medium or a non-transitory machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the methods described herein can be stored in such software processes on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid-state drive, etc.; further, the storage medium may also include a combination of the above-mentioned types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code, and when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the methods shown in the above embodiments are implemented.

[0100] A part of the present invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can, through the operation of the computer, call or provide the methods and / or technical solutions according to the present invention. Those skilled in the art should understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to the computer.

[0101] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for switching hybrid vehicle modes, characterized in that, The method includes: Obtaining the power transmission system parameters of a hybrid vehicle; Dividing the process of switching the hybrid vehicle from series drive to parallel drive into a first stage before clutch engagement and a second stage during clutch engagement, and based on the power transmission system parameters, establishing a first state equation corresponding to the first stage with the generator torque as a variable, and establishing a second state equation corresponding to the second stage with the clutch engagement normal pressure change rate as a variable; Taking the minimum time consumption of the first stage as the optimization objective of the first state equation, taking the minimum angular acceleration of the clutch passive end in the second stage as the optimization objective of the second state equation, and based on the angular velocity of the clutch active end, establishing a connection constraint between the first state equation and the second state equation, and jointly solving the first state equation and the second state equation to obtain the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage; Controlling the process of switching the hybrid vehicle from series drive to parallel drive based on the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage.

2. The method according to claim 1, wherein The controlling the process of switching the hybrid vehicle from series drive to parallel drive based on the optimal generator torque corresponding to the first stage and the optimal clutch engagement normal pressure change rate corresponding to the second stage includes: When the hybrid vehicle is in the first stage of switching from series drive to parallel drive, controlling the generator based on the optimal generator torque corresponding to the first stage; When the hybrid vehicle is in the second stage of switching from series drive to parallel drive, determining the optimal clutch normal pressure based on the optimal clutch engagement normal pressure change rate corresponding to the second stage and controlling the clutch.

3. The method according to claim 2, characterized in that, The process of jointly solving the first state equation and the second state equation further includes: Taking the engagement speed difference as a variable, and establishing a constraint of the first state equation with the difference between the angular velocity of the clutch active end and the angular velocity of the clutch passive end at the end of the first stage not being greater than the engagement speed difference, so as to jointly solve to obtain the target engagement speed difference.

4. The method according to claim 3, wherein The method further includes: Obtaining the current angular velocity of the clutch active end and the current angular velocity of the clutch passive end during the process of switching the hybrid vehicle from series drive to parallel drive; Judging whether the difference between the current angular velocity of the clutch active end and the current angular velocity of the clutch passive end is greater than the target engagement speed difference; When the difference between the current angular velocity of the clutch active end and the current angular velocity of the clutch passive end is greater than the target engagement speed difference, determining that the hybrid vehicle is in the first stage of switching from series drive to parallel drive.

5. The method according to claim 4, wherein The method further includes: When the difference between the current angular velocity of the clutch active end and the current angular velocity of the clutch passive end is not greater than the target engagement speed difference, determining that the hybrid vehicle is in the second stage of switching from series drive to parallel drive.

6. The method according to claim 1, wherein Establishing the connection constraint between the first state equation and the second state equation based on the angular velocity of the clutch driving end includes: Establishing the connection constraint between the first state equation and the second state equation based on the equality of the angular velocity of the clutch driving end at the end of the first stage and the angular velocity of the clutch driving end at the beginning of the second stage.

7. The method according to claim 1, characterized in that, The process of jointly solving the first state equation and the second state equation further includes: Establishing the constraint of the first state equation with the generator torque corresponding to the start and end of the first stage being zero; Establishing the constraint of the second state equation with the change rate of the clutch engagement positive pressure corresponding to the start and end of the second stage being zero, and the angular velocity of the clutch driving end being equal to the angular velocity of the clutch driven end at the end of the second stage.

8. The method according to any one of claims 1-7, characterized in that, Based on the parameters of the power transmission system, establishing the first state equation corresponding to the first stage with the generator torque as the variable, and establishing the second state equation corresponding to the second stage with the change rate of the clutch engagement positive pressure as the variable, includes: Respectively establishing the first vehicle dynamics model corresponding to the first stage and the second vehicle dynamics model corresponding to the second stage based on the parameters of the power transmission system; Based on the first vehicle dynamics model, establishing the first state equation corresponding to the first stage with the generator torque as the variable, and based on the second vehicle dynamics model, establishing the second state equation corresponding to the second stage with the change rate of the clutch engagement positive pressure as the variable.

9. A hybrid vehicle mode switching device, characterized in that, The device includes: An acquisition module, configured to acquire the parameters of the power transmission system of the hybrid vehicle; A first processing module, configured to divide the process of switching the hybrid vehicle from series drive to parallel drive into a first stage before clutch engagement and a second stage of clutch engagement, and based on the parameters of the power transmission system, establish the first state equation corresponding to the first stage with the generator torque as the variable, and establish the second state equation corresponding to the second stage with the change rate of the clutch engagement positive pressure as the variable; A second processing module, configured to take the minimum time consumption of the first stage as the optimization objective of the first state equation, take the minimum angular acceleration of the clutch driven end in the second stage as the optimization objective of the second state equation, and establish the connection constraint between the first state equation and the second state equation based on the angular velocity of the clutch driving end, and jointly solve the first state equation and the second state equation to obtain the optimal generator torque corresponding to the first stage and the optimal change rate of the clutch engagement positive pressure corresponding to the second stage; A third processing module, configured to control the process of switching the hybrid vehicle from series drive to parallel drive based on the optimal generator torque corresponding to the first stage and the optimal change rate of the first clutch engagement positive pressure corresponding to the second stage.

10. A vehicle, the vehicle being a hybrid vehicle, characterized in that, The vehicle includes: a controller, and the controller includes: A memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to execute the method according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that, Computer instructions are stored on the computer-readable storage medium, and the computer instructions are used to cause a computer to execute the method according to any one of claims 1 to 8.

12. A computer program product, characterized in that, It includes computer instructions, and the computer instructions are used to cause a computer to execute the method according to any one of claims 1 to 8.

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