Torque control method for vehicle engine, vehicle and torque control device

Abstract

The application discloses a torque control method of a vehicle engine, a vehicle and a torque control device, and the method comprises the following steps: obtaining an initial torque of the engine; obtaining a torque step of a current torque period according to the initial torque and a wheel end torque of a last torque period; in response to the engine torque control function being in an activated state, obtaining a maximum torque and a minimum torque of the current torque period according to the initial torque and the torque step of the current torque period; and performing torque limiting control on the engine according to the maximum torque and the minimum torque. Thus, the method is suitable for a 48V BSG_P0 micro-hybrid vehicle equipped with a 9AT gearbox, the working condition can be accurately identified in advance, the engine torque can be accurately and greatly limited in a short time, the rising amplitude of the engine speed is slowed down, and the occurrence of the 9AT gearbox breaking working condition is effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a torque control method for a vehicle engine, a vehicle, and a torque control device. Background Technology

[0002] The 48V-BSG system in hybrid electric vehicles is a type of mild hybrid system. The 48V mild hybrid system adds a 48V hybrid system to a 12V system, meaning it simultaneously incorporates a 48V lithium-ion battery and a traditional 12V battery. The 12V battery system handles traditional loads such as lighting, ignition, entertainment, and audio systems, while the 48V battery system powers the active chassis system, regenerative braking system, etc. Thus, by adding a 48V battery system to a traditional vehicle, it can achieve functions such as charging while driving, acceleration assistance, energy recovery, and electric crawl control. Compared to traditional vehicles, it is more fuel-efficient and less expensive, significantly improving the user experience. BSG (Belt-Driven Starter Generator) technology connects the electric motor to the engine via a belt-driven mechanism at the front end of the engine, replacing the vehicle's original 12V alternator. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in the related art. Therefore, the first objective of this invention is to propose a torque control method for a vehicle engine, applicable to 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, the method can precisely and significantly limit the engine torque in a short time, slowing down the rate of engine speed increase and effectively preventing the 9AT transmission from jerking.

[0004] The second objective of this invention is to provide a vehicle.

[0005] The third objective of this invention is to provide a torque control device for a vehicle engine.

[0006] To achieve the above objectives, a first aspect of the present invention provides a torque control method for a vehicle engine, comprising: acquiring the initial torque of the engine; acquiring the torque step size of the current torque cycle based on the initial torque and the wheel end torque of the previous torque cycle; in response to the engine torque control function being activated, acquiring the maximum torque and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle; and performing torque limiting control on the engine based on the maximum torque and minimum torque.

[0007] The torque control method for a vehicle engine according to an embodiment of the present invention obtains the initial torque of the engine, and obtains the torque step size of the current torque cycle based on the initial torque and the wheel-end torque of the previous torque cycle. Furthermore, by responding to the engine torque control function being active, the maximum and minimum torque of the current torque cycle are obtained based on the initial torque and the torque step size of the current torque cycle, and torque limiting control of the engine is performed based on the maximum and minimum torque. Therefore, this method is suitable for 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, it can precisely and significantly limit the engine torque in a short time, slowing down the rate of engine speed increase and effectively preventing the 9AT transmission from jerking.

[0008] According to one embodiment of the present invention, obtaining the initial torque of an engine includes: obtaining engine loss torque, vehicle accessory torque, and vehicle accessory loss torque; and obtaining the initial torque of the engine based on the engine loss torque, vehicle accessory torque, and vehicle accessory loss torque.

[0009] According to one embodiment of the present invention, obtaining the torque step size of the current torque cycle based on the initial torque and the wheel end torque of the previous torque cycle includes: obtaining the absolute value of the torque difference between the initial torque and the wheel end torque of the previous torque cycle; obtaining the torque step size correction coefficient of the current torque cycle; and multiplying the square of the absolute value, the torque step size correction coefficient of the current torque cycle, and the torque cycle to obtain the torque step size of the current torque cycle.

[0010] According to one embodiment of the present invention, obtaining the torque step correction coefficient of the current torque cycle includes: obtaining the current accelerator pedal opening; and obtaining the torque step correction coefficient of the current torque cycle based on the current accelerator pedal opening.

[0011] According to one embodiment of the present invention, obtaining the maximum torque and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle includes: adding the maximum torque of the previous torque cycle to the torque step size of the current torque cycle to obtain the maximum torque of the current torque cycle, wherein, in the first torque cycle, the maximum torque is the initial torque; subtracting the torque step size of the current torque cycle from the minimum torque of the previous torque cycle to obtain the minimum torque of the current torque cycle, wherein, in the first torque cycle, the minimum torque is the smaller value of the initial torque and the wheel end torque of the last torque cycle before the engine torque control function is activated.

[0012] According to one embodiment of the present invention, the method further includes: identifying whether the engine is in a through-shaft condition, whether the accelerator pedal is depressed, and whether the engine torque control function is in a restricted state; if the engine is in a through-shaft condition, the accelerator pedal is depressed, and the engine torque control function is in an unrestricted state, then it is determined that the engine torque control function is in an active state.

[0013] According to one embodiment of the present invention, identifying whether an engine is in a through-shaft condition includes: acquiring engine speed, transmission turbine speed, and vehicle transmission ratio; acquiring engine speed gradient based on engine speed; determining a maximum speed difference threshold and a minimum speed difference threshold based on the speed gradient and vehicle transmission ratio; and determining that the engine is in a through-shaft condition if the speed difference between the engine speed and the transmission turbine speed is between the maximum speed difference threshold and the minimum speed difference threshold.

[0014] According to one embodiment of the present invention, identifying whether the engine torque control function is in a restricted state includes: if the vehicle's electronic stability system and automatic transmission adjustment system are not activated, the transmission clutch is in the open state, and the vehicle speed is within a preset speed range, then it is determined that the engine torque control function is in an unrestricted state.

[0015] To achieve the above objectives, a second aspect of the present invention provides a vehicle, including: a memory, a processor, and a torque control program for a vehicle engine stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described torque control method for the vehicle engine.

[0016] According to embodiments of the present invention, the vehicle obtains the initial torque of the engine, and obtains the torque step size of the current torque cycle based on the initial torque and the wheel-end torque of the previous torque cycle. Furthermore, by responding to the engine torque control function being activated, the maximum and minimum torque of the current torque cycle are obtained based on the initial torque and the torque step size of the current torque cycle, and torque-limiting control of the engine is performed based on the maximum and minimum torque. Therefore, this method is suitable for 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, it can precisely and significantly limit the engine torque in a short time, slowing down the rate of engine speed increase and effectively preventing the 9AT transmission from jerking during operation.

[0017] To achieve the above objectives, a third aspect of the present invention provides a torque control device for a vehicle engine. The device includes: an acquisition module, configured to acquire the initial torque of the engine, acquire the torque step size of the current torque cycle based on the initial torque and the wheel end torque of the previous torque cycle, and acquire the maximum torque and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle in response to the engine torque control function being activated; and a control module, configured to perform torque limiting control on the engine based on the maximum torque and the minimum torque.

[0018] The torque control device for a vehicle engine according to an embodiment of the present invention acquires the initial torque of the engine through an acquisition module, and acquires the torque step size of the current torque cycle based on the initial torque and the wheel-end torque of the previous torque cycle. In response to the engine torque control function being activated, it acquires the maximum and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle, and performs torque limiting control on the engine based on the maximum and minimum torque through a control module. Therefore, it is suitable for 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, it can precisely and significantly limit the engine torque in a short time, slowing down the rate of engine speed increase and effectively avoiding the occurrence of jerkiness in the 9AT transmission.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a 48V BSG_P0 mild hybrid vehicle according to an embodiment of the present invention; Figure 2 A flowchart of a torque control method for a vehicle engine according to an embodiment of the present invention; Figure 3 This is a partial flowchart of a torque control method for a vehicle engine according to another embodiment of the present invention; Figure 4 For relative to Figure 3 Another part of the flowchart; Figure 5 This is a structural block diagram of a vehicle according to an embodiment of the present invention; Figure 6 This is a structural block diagram of a torque control device for a vehicle engine according to an embodiment of the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] It should be noted that this application is applicable to 48V BSG_P0 mild hybrid vehicles, see reference. Figure 1As shown, the 48V BSG_P0 mild hybrid vehicle 100 may include an engine 110, a transmission 120, a 48V power battery 130, a 12V battery 140, a BSG motor 150, a DC-DC (Direct Current-Direct Current) converter 160, etc.

[0023] The system comprises: an engine 110 (which can be a conventional engine); a transmission 120 (which can be a 9-speed automatic transmission); a BSG motor 150 connected to the engine 110 via a belt drive mechanism at the front end; a 12V battery 140 handling conventional loads such as lighting, ignition, entertainment, and audio systems; and a 48V power battery 130 supporting the active chassis system and regenerative braking system. Therefore, by adding a 48V power battery 130 to a conventional vehicle, it can achieve functions such as charging while driving, acceleration assistance, energy recovery, and electric crawling, resulting in better fuel economy than conventional vehicles at a low cost, while significantly improving the user experience.

[0024] However, when a hybrid 48V BSG_P0 model is equipped with a 9AT transmission, the 9AT transmission clutch (torque converter) has a flexible connection in its OPEN state. At low vehicle speeds, the 9AT transmission clutch needs to be in the OPEN state in a fixed gear to prevent the engine from stalling due to heavy wheel load. During vehicle coasting and acceleration, the 9AT transmission clutch, in the OPEN state, relies on hydraulic compression to transmit power. The pump wheel speed connected to the engine crosses the turbine speed, causing turbine speed fluctuations and resulting in slight impact noises throughout the vehicle. However, the solutions used in traditional vehicles equipped with 9AT transmissions and common new energy vehicles are limited by their architecture; they do not filter wheel torque and are not based on a 48V BSG architecture, therefore they cannot be used in 48V BSG_P0 mild hybrid vehicles.

[0025] Based on this, this application provides a torque control method for a vehicle engine, a vehicle, and a torque control device, which is applicable to 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, the engine torque can be precisely and significantly limited in a short period of time, slowing down the rise in engine speed and effectively avoiding the occurrence of jerkiness in the 9AT transmission.

[0026] The following description, with reference to the accompanying drawings, describes a torque control method for a vehicle engine, a vehicle, and a torque control device provided in an embodiment of the present invention.

[0027] Figure 2 A flowchart of a vehicle engine torque control method according to an embodiment of the present invention is shown below. Figure 2 As shown, the torque control method for the vehicle engine may include the following steps: Step S201: Obtain the initial torque of the engine.

[0028] It should be noted that the initial torque of the engine can be the torque of the engine in a "zero" torque state, that is, the zero torque of the engine. By limiting the initial torque of the engine to zero torque, it is possible to ensure the normal torque use of the vehicle, while also minimizing the rate of engine speed increase, thereby reducing the impact on the transmission turbine speed during engine speed transitions.

[0029] In one embodiment, reference Figure 3 As shown, obtaining the initial torque of the engine includes: obtaining the engine loss torque, vehicle accessory torque, and vehicle accessory loss torque; and obtaining the initial torque of the engine based on the engine loss torque, vehicle accessory torque, and vehicle accessory loss torque. Specifically, when obtaining the zero torque of the engine, the engine loss torque, vehicle accessory torque, and vehicle accessory loss torque can be obtained first. By adding the engine loss torque to the vehicle accessory loss torque and then subtracting the vehicle accessory torque (which is itself a negative value), the zero torque of the engine can be obtained.

[0030] Step S202: Obtain the torque step size of the current torque cycle based on the initial torque and the wheel end torque of the previous torque cycle.

[0031] The torque period refers to the period of the torque signal. In a specific example, the torque period can be 10ms. The torque step size of the current torque period refers to the change in the torque limit value of the current torque period compared to the previous torque period.

[0032] In one embodiment, continue to refer to Figure 3 As shown, the torque step size of the current torque cycle is obtained based on the initial torque and the wheel end torque of the previous torque cycle, including: obtaining the absolute value of the torque difference between the initial torque and the wheel end torque of the previous torque cycle; obtaining the torque step size correction coefficient of the current torque cycle; and multiplying the square of the absolute value, the torque step size correction coefficient of the current torque cycle, and the torque cycle to obtain the torque step size of the current torque cycle.

[0033] Specifically, to obtain the torque step size for the current torque cycle, it is necessary to obtain the initial torque, the wheel-end torque of the previous torque cycle (i.e., the wheel-end filtered torque), the torque step size correction factor, and the torque cycle. The torque step size for the current torque cycle is the product of these three factors: the torque step size correction factor, the torque cycle, and the square of the absolute value of the difference between the initial torque and the wheel-end torque of the previous torque cycle. The torque step size correction factor can be a coefficient related to the accelerator pedal opening; the torque cycle is the torque signal period. Since the torque gradient needs to be superimposed onto the final calculated torque using the torque cycle, it needs to be multiplied by the torque cycle when calculating the torque step size for the current torque cycle.

[0034] Further reference Figure 3 As shown, obtaining the torque step correction coefficient for the current torque cycle includes: obtaining the current accelerator pedal opening; and obtaining the torque step correction coefficient for the current torque cycle based on the current accelerator pedal opening. Specifically, pedal opening refers to the accelerator pedal opening. Since a large pedal opening causes the engine speed to rise faster, resulting in more drastic fluctuations in the transmission turbo speed, it is preferable to correct the torque step based on the pedal opening. In a specific example, the current accelerator pedal opening can be substituted into a one-dimensional calibration chart to obtain the torque step correction coefficient for the current torque cycle.

[0035] Step S203: In response to the engine torque control function being activated, obtain the maximum and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle.

[0036] Specifically, when it is anticipated that the transmission is about to experience a jerk, the engine torque control function is activated. After activating the engine torque control function, the torque limit for the current torque cycle can be obtained based on the current zero torque of the engine and the torque step size of the current torque cycle.

[0037] In one embodiment, continue to refer to Figure 3 As shown, the maximum and minimum torques of the current torque cycle are obtained based on the initial torque and the torque step size of the current torque cycle, including: adding the maximum torque of the previous torque cycle to the torque step size of the current torque cycle to obtain the maximum torque of the current torque cycle, wherein, in the first torque cycle, the maximum torque is the initial torque; subtracting the torque step size of the current torque cycle from the minimum torque of the previous torque cycle to obtain the minimum torque of the current torque cycle, wherein, in the first torque cycle, the minimum torque is the smaller value of the initial torque and the wheel end torque of the last torque cycle before the engine torque control function is activated.

[0038] Specifically, when calculating the maximum torque, if the torque control function is not active, the maximum torque of the current torque cycle is not limited. If the torque control function is active, a rising edge detection is performed to limit the maximum torque of the first cycle to the engine's zero torque. In subsequent torque cycles, the torque step size is added to the engine's zero torque using an accumulator. For example, when the torque step size is 10ms, the engine's zero torque is added every 10ms to obtain the maximum torque, causing the upper limit of torque to rise in the shape of a positive quadratic function curve in the first quadrant.

[0039] When calculating the minimum torque, if the torque control function is not active, the minimum torque for the current torque cycle is not limited. If the torque control function is active, a rising edge detection is performed to limit the minimum torque of the first cycle to the smaller of the engine zero torque and the wheel-end torque of the last torque cycle before the engine torque control function was activated. In subsequent torque cycles, an accumulator is used to subtract the torque step size from the smaller of the engine zero torque and the wheel-end torque of the last torque cycle before the engine torque control function was activated. For example, when the torque step size is 10ms, the torque step size is subtracted from the smaller of the engine zero torque and the wheel-end torque of the last torque cycle before the engine torque control function was activated every 10ms to obtain the minimum torque, causing the lower limit of torque to decrease in the shape of a negative quadratic function curve in the fourth quadrant.

[0040] Step S204: Perform torque limiting control on the engine based on the maximum torque and minimum torque.

[0041] Specifically, by calculating the maximum and minimum torque of the current torque cycle, the upper limit of torque is set to rise in the first quadrant as a positive quadratic function, while the lower limit of torque is set to fall in the fourth quadrant as a negative quadratic function. During the current torque cycle, the engine torque is controlled to be limited between the maximum and minimum torque. This ensures a smooth torque increase while also limiting torque output, thereby effectively preventing transmission jerking by slowing down the rate of engine speed increase.

[0042] Understandably, the torque control strategy for the engine to prevent transmission jerking mainly involves limiting the engine torque based on the maximum torque, while limiting the engine torque based on the minimum torque is a corresponding redundancy strategy.

[0043] It should be understood that, although Figure 2 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 2 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0044] The torque control method for a vehicle engine according to an embodiment of the present invention obtains the initial torque of the engine, and obtains the torque step size of the current torque cycle based on the initial torque and the wheel-end torque of the previous torque cycle. Furthermore, by responding to the engine torque control function being active, the maximum and minimum torque of the current torque cycle are obtained based on the initial torque and the torque step size of the current torque cycle, and torque limiting control of the engine is performed based on the maximum and minimum torque. Therefore, this method is suitable for 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, it can precisely and significantly limit the engine torque in a short time, slowing down the rate of engine speed increase and effectively preventing the 9AT transmission from jerking.

[0045] In one embodiment, reference Figure 4 As shown, the method further includes: identifying whether the engine is in a through-shaft condition, whether the accelerator pedal is depressed, and whether the engine torque control function is in a restricted state; if the engine is in a through-shaft condition, the accelerator pedal is depressed, and the engine torque control function is in an unrestricted state, then it is determined that the engine torque control function is in an active state.

[0046] It should be noted that the "cross-shaft" condition refers to the process where the transmission pump wheel speed (i.e., engine speed) crosses the turbine speed. Whether the accelerator pedal is depressed can be determined by the accelerator pedal opening; when the opening exceeds a calibrable value, the accelerator pedal is considered depressed. The unrestricted state of the engine torque control function means that the engine torque control function is only applicable under this state. Specific factors contributing to this unrestricted state include: low likelihood of false triggering, no impact on higher-priority functions, or fulfillment of other preconditions. In other words, if it is determined that the engine is in the process of the transmission pump wheel speed crossing the turbine speed, the accelerator pedal is depressed but low likelihood of false triggering, no impact on higher-priority functions, or fulfillment of other preconditions, then the engine torque control function is activated.

[0047] In one embodiment, reference Figure 4 As shown, identifying whether the engine is in a through-shaft condition includes: acquiring the engine speed, transmission turbine speed, and vehicle transmission ratio; acquiring the engine speed gradient based on the engine speed; determining the maximum speed difference threshold and the minimum speed difference threshold based on the speed gradient and the vehicle transmission ratio; if the speed difference between the engine speed and the transmission turbine speed is between the maximum speed difference threshold and the minimum speed difference threshold, it is determined that the engine is in a through-shaft condition.

[0048] In other words, the transmission shaft failure condition can be identified by whether the speed difference between the engine speed and the transmission turbine speed is within a threshold range. Specifically, it is necessary to determine when the engine speed will cross the transmission speed. Since transmission speed fluctuations are delayed, it is necessary to identify in advance whether the engine speed will cross the transmission speed. Therefore, this can be measured by the gradient of engine speed changes. In a specific example, when determining the gradient of engine speed changes, the engine speed (X) of the most recent seven cycle intervals (which can be labeled) can be taken first. n X n-1 X n-2 X n-3 X n-4 X n-5 X n-6 ), and then according to Y n =X n -X n-1 Calculate the speed difference (Y) between the current cycle and the previous cycle. n Y n-1 Y n-2 Y n-3 Y n-4 Y n-5 ), and then according to Z n =Y n -Y n-1 Calculate the engine variation gradient (Z) for the most recent five cycles. n Z n-1 Z n-2 Z n-3 Z n-4 And it can be averaged to determine the engine speed gradient, i.e. The greater the gradient of engine speed change, the larger the range of speed difference needs to be set. The setting of the range can depend on the gradient of engine speed change and the vehicle's gear ratio (also known as the vehicle's rotational speed ratio, i.e., the speed ratio from the engine flywheel end to the vehicle wheel end, which may include the gearbox ratio, the final drive ratio, and the transfer case ratio). In a specific example, the obtained engine speed change gradient and vehicle gear ratio can be substituted into an empirical chart to obtain the maximum and minimum speed difference thresholds. If the speed difference between the engine speed and the gearbox turbine speed is between the maximum and minimum speed difference thresholds, it is identified as the engine being in a cross-axle operating condition, which is one of the prerequisites for activating the engine torque control function.

[0049] In one embodiment, continue to refer to Figure 4As shown, identifying whether the engine torque control function is in a restricted state includes: if the vehicle's Electronic Stability Program (ESP) and Transmission Control Unit (TCU) are not activated, the transmission clutch is open, and the vehicle speed is within a preset speed range, then the engine torque control function is determined to be in an unrestricted state.

[0050] In other words, higher-priority suppression activation conditions can be set. Once a suppression activation condition is triggered, the torque control function is prohibited from activation. Considering that the electronic stability control system or the automatic transmission adjustment system is activated, which involves torque increase or decrease, and thus has a higher priority, the activation of the electronic stability control system or the automatic transmission adjustment system is one of the suppression activation conditions. Since the transmission jerk condition only triggers when the transmission clutch is open, the transmission clutch being closed is one of the suppression activation conditions. Because the vehicle speed must be within a preset speed range to avoid erroneous function triggering at unexpected speeds, the vehicle speed being outside the preset speed range (e.g., excessively high speed) is one of the suppression activation conditions. When the above suppression activation conditions are not met, the engine torque control function is in an unrestricted state.

[0051] In summary, the torque control method for a vehicle engine according to embodiments of the present invention obtains the initial torque of the engine, and obtains the torque step size of the current torque cycle based on the initial torque and the wheel-end torque of the previous torque cycle. Furthermore, by responding to the engine torque control function being active, the maximum and minimum torque of the current torque cycle are obtained based on the initial torque and the torque step size of the current torque cycle, and torque limiting control of the engine is performed based on the maximum and minimum torque. Therefore, this method is suitable for 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, it can precisely and significantly limit the engine torque in a short time, slowing down the increase in engine speed and effectively preventing the 9AT transmission from jerking.

[0052] Figure 5 This is a structural block diagram of a vehicle according to an embodiment of the present invention. (Reference) Figure 5 As shown, the vehicle 300 includes: a memory 301, a processor 302, and a torque control program for the vehicle engine stored in the memory 301 and executable on the processor 302. When the processor 302 executes the program, it implements the torque control method for the vehicle engine described above.

[0053] According to embodiments of the present invention, the vehicle obtains the initial torque of the engine, and obtains the torque step size of the current torque cycle based on the initial torque and the wheel-end torque of the previous torque cycle. Furthermore, by responding to the engine torque control function being activated, the maximum and minimum torque of the current torque cycle are obtained based on the initial torque and the torque step size of the current torque cycle, and torque-limiting control of the engine is performed based on the maximum and minimum torque. Therefore, this method is suitable for 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, it can precisely and significantly limit the engine torque in a short time, slowing down the rate of engine speed increase and effectively preventing the 9AT transmission from jerking during operation.

[0054] Figure 6 This is a structural block diagram of a torque control device for a vehicle engine according to an embodiment of the present invention. (Reference) Figure 6 As shown, the torque control device 400 of the vehicle engine includes an acquisition module 401 and a control module 402.

[0055] The acquisition module 401 is used to acquire the initial torque of the engine, and to acquire the torque step size of the current torque cycle based on the initial torque and the wheel end torque of the previous torque cycle. In response to the engine torque control function being activated, the maximum torque and minimum torque of the current torque cycle are acquired based on the initial torque and the torque step size of the current torque cycle. The control module 402 is used to perform torque limiting control on the engine based on the maximum torque and minimum torque.

[0056] In one embodiment, the acquisition module 401 is specifically used to: acquire engine loss torque, vehicle accessory torque, and vehicle accessory loss torque; and acquire the initial torque of the engine based on the engine loss torque, vehicle accessory torque, and vehicle accessory loss torque.

[0057] In one embodiment, the acquisition module 401 is specifically used to: acquire the absolute value of the torque difference between the initial torque and the wheel end torque of the previous torque cycle; acquire the torque step size correction coefficient of the current torque cycle; and multiply the square of the absolute value, the torque step size correction coefficient of the current torque cycle, and the torque cycle to obtain the torque step size of the current torque cycle.

[0058] In one embodiment, the acquisition module 401 is specifically used to: acquire the current accelerator pedal opening; and acquire the torque step correction coefficient of the current torque cycle based on the current accelerator pedal opening.

[0059] In one embodiment, the acquisition module 401 is specifically used to: add the maximum torque of the previous torque cycle to the torque step size of the current torque cycle to obtain the maximum torque of the current torque cycle, wherein, in the first torque cycle, the maximum torque is the initial torque; subtract the torque step size of the current torque cycle from the minimum torque of the previous torque cycle to obtain the minimum torque of the current torque cycle, wherein, in the first torque cycle, the minimum torque is the smaller value of the initial torque and the wheel end torque of the previous torque cycle.

[0060] In one embodiment, the torque control device 400 of the vehicle engine further includes an identification module (not shown in the figure), which is used to: identify whether the engine is in axle-crossing condition, whether the accelerator pedal is depressed, and whether the engine torque control function is in a restricted state; if the engine is in axle-crossing condition, the accelerator pedal is depressed, and the engine torque control function is in an unrestricted state, then it is determined that the engine torque control function is in an active state.

[0061] In one embodiment, the identification module is specifically used to: acquire engine speed, transmission turbine speed and vehicle transmission ratio; acquire engine speed gradient based on engine speed; determine maximum speed difference threshold and minimum speed difference threshold based on speed gradient and vehicle transmission ratio; if the speed difference between engine speed and transmission turbine speed is between the maximum speed difference threshold and the minimum speed difference threshold, determine that the engine is in a shaft-crossing condition.

[0062] In one embodiment, the identification module is specifically used to: determine that the engine torque control function is in an unrestricted state if the vehicle's electronic stability system and automatic transmission adjustment system are not activated, the transmission clutch is in the open state, and the vehicle speed is within a preset speed range.

[0063] It should be noted that for the description of the torque control device for the vehicle engine in this application, please refer to the description of the torque control method for the vehicle engine in this application, and will not be repeated here.

[0064] The torque control device for a vehicle engine according to an embodiment of the present invention acquires the initial torque of the engine through an acquisition module, and acquires the torque step size of the current torque cycle based on the initial torque and the wheel-end torque of the previous torque cycle. In response to the engine torque control function being activated, it acquires the maximum and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle, and performs torque limiting control on the engine based on the maximum and minimum torque through a control module. Therefore, it is suitable for 48V BSG_P0 mild hybrid vehicles equipped with a 9AT transmission. By accurately identifying the operating conditions in advance, it can precisely and significantly limit the engine torque in a short time, slowing down the rate of engine speed increase and effectively avoiding the occurrence of jerkiness in the 9AT transmission.

[0065] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0066] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0067] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A torque control method for a vehicle engine, characterized in that, The method includes: Obtain the initial torque of the engine; The torque step size of the current torque cycle is obtained based on the initial torque and the wheel end torque of the previous torque cycle. When the engine torque control function is activated, the maximum and minimum torque of the current torque cycle are obtained based on the initial torque and the torque step size of the current torque cycle. The engine is subjected to torque limiting control based on the maximum torque and the minimum torque; wherein, in the current torque cycle, the torque of the engine is controlled to be limited between the maximum torque and the minimum torque, and the upper limit of torque is made to rise in the shape of a positive quadratic function in the first quadrant, and the lower limit of torque is made to fall in the shape of a negative quadratic function in the fourth quadrant. The method further includes: The system identifies whether the engine is in a through-shaft condition, whether the accelerator pedal is depressed, and whether the engine torque control function is in a restricted state; wherein, the through-shaft condition refers to the process in which the transmission pump wheel speed crosses the turbine speed; If the engine is in the through-shaft condition, the accelerator pedal is depressed, and the engine torque control function is in an unrestricted state, then the engine torque control function is determined to be in an active state.

2. The torque control method for a vehicle engine according to claim 1, characterized in that, The process of obtaining the initial torque of the engine includes: Obtain engine loss torque, vehicle accessory torque, and vehicle accessory loss torque; The initial torque of the engine is obtained based on the engine loss torque, the vehicle accessory torque, and the vehicle accessory loss torque.

3. The torque control method for a vehicle engine according to claim 1, characterized in that, The step of obtaining the torque step size of the current torque cycle based on the initial torque and the wheel end torque of the previous torque cycle includes: Obtain the absolute value of the torque difference between the initial torque and the wheel-end torque of the previous torque cycle; Obtain the torque step size correction factor for the current torque cycle; The torque step size of the current torque cycle is obtained by multiplying the square of the absolute value, the torque step size correction factor of the current torque cycle, and the torque cycle.

4. The torque control method for a vehicle engine according to claim 3, characterized in that, The step size correction coefficient for obtaining the current torque cycle includes: Get the current accelerator pedal opening; The torque step correction coefficient for the current torque cycle is obtained based on the current accelerator pedal opening.

5. The torque control method for a vehicle engine according to claim 1, characterized in that, The step of obtaining the maximum and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle includes: The maximum torque of the current torque cycle is obtained by adding the maximum torque of the previous torque cycle to the torque step size of the current torque cycle, wherein, in the first torque cycle, the maximum torque is the initial torque; The minimum torque of the current torque cycle is obtained by subtracting the torque step size of the current torque cycle from the minimum torque of the previous torque cycle. In the first torque cycle, the minimum torque is the smaller value of the initial torque and the wheel-end torque of the last torque cycle before the engine torque control function is activated.

6. The torque control method for a vehicle engine according to claim 1, characterized in that, The process of identifying whether the engine is in a shaft-crossing condition includes: Obtain engine speed, transmission turbine speed, and vehicle gear ratio; The engine speed gradient is obtained based on the engine speed. The maximum speed difference threshold and the minimum speed difference threshold are determined based on the speed gradient and the vehicle transmission ratio; If the speed difference between the engine speed and the gearbox turbine speed is between the maximum speed difference threshold and the minimum speed difference threshold, the engine is determined to be in the shaft-crossing condition.

7. The torque control method for a vehicle engine according to claim 1, characterized in that, Identify whether the engine torque control function is in a restricted state, including: If the vehicle's electronic stability control system and automatic transmission adjustment system are not activated, the transmission clutch is open, and the vehicle speed is within the preset speed range, then the engine torque control function is determined to be in an unrestricted state.

8. A vehicle, characterized in that, include: A memory, a processor, and a torque control program for a vehicle engine stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the torque control method for a vehicle engine according to any one of claims 1-7.

9. A torque control device for a vehicle engine, characterized in that, The apparatus for implementing the torque control method for a vehicle engine according to any one of claims 1-7 comprises: The acquisition module is used to acquire the initial torque of the engine, and to acquire the torque step size of the current torque cycle based on the initial torque and the wheel end torque of the previous torque cycle. In response to the engine torque control function being activated, the module acquires the maximum torque and minimum torque of the current torque cycle based on the initial torque and the torque step size of the current torque cycle. A control module is used to perform torque limiting control on the engine based on the maximum torque and the minimum torque.

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