Torque control method and device of electric automobile

Abstract

The invention discloses a torque control method and device for an electric vehicle, and relates to the technical field of new energy vehicles. The method comprises the steps that the actual torque of a motor in the electric automobile is obtained, and the required torque of the electric automobile is obtained; judging whether a difference value between the required torque and the actual torque is greater than a preset difference value; when the difference value between the required torque and the actual torque is greater than a preset difference value, integrating the difference value between the required torque and the actual torque according to a preset duration to obtain an unexpected acceleration risk degree index; and when the unexpected acceleration risk degree index is larger than a first preset value, the demand torque of the electric vehicle is limited based on the unexpected acceleration risk degree index. According to the method, the unexpected acceleration risk degree index is obtained based on the integral of the torque difference to the time, and the demand torque is limited based on the unexpected acceleration risk degree index to prevent unexpected acceleration and ensure the stability of power output of the electric vehicle, so that the driving experience and the kinetic energy safety of the electric vehicle are improved.

Description

Technical Field

[0001] This application relates to the technical field of new energy vehicles, and particularly to a torque control method and device for an electric vehicle. Background Art

[0002] In daily life, cars have become one of the indispensable means of transportation for users. With the rapid development of science and technology, electric vehicles (such as pure electric vehicles, hybrid electric vehicles, etc.) are more and more widely used. And with the development of science and technology, users have higher requirements for the driving experience and functional safety of electric vehicles.

[0003] However, in different scenarios, an electric vehicle may have different unexpected acceleration risks. For example, when the user continuously presses the accelerator pedal, the required torque of the electric vehicle may be limited by speed limits or other fault sources, resulting in the output torque of the electric vehicle's motor being limited. When the required torque no longer has speed limits or other fault source limitations at a certain moment, there will be an unexpected acceleration risk. The unexpected acceleration risk may cause the electric vehicle to suddenly accelerate, affecting the stability of the vehicle's power output, and thus affecting the driving experience and functional safety of the electric vehicle.

[0004] In summary, there is an unexpected acceleration risk in daily life, which will seriously affect the stability of the power output of electric vehicles, and thus affect the driving experience and functional safety of electric vehicles. Summary of the Invention

[0005] Based on the above problems, this application provides a torque control method and device for an electric vehicle, which ensures the stability of the power output of the electric vehicle, thereby improving the driving experience and functional safety of the electric vehicle.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, this application provides a torque control method for an electric vehicle, including:

[0008] Obtain the actual torque of the motor in the electric vehicle, and obtain the required torque of the electric vehicle;

[0009] Judge whether the difference between the required torque and the actual torque is greater than a preset difference;

[0010] When the difference between the required torque and the actual torque is greater than the preset difference, integrate the difference between the required torque and the actual torque according to a preset duration to obtain an unexpected acceleration risk degree index;

[0011] When the unexpected acceleration risk degree index is greater than a first preset value, limit the required torque of the electric vehicle based on the unexpected acceleration risk degree index.

[0012] Optionally, the method further includes:

[0013] When the unexpected acceleration risk index is greater than the first preset value, a risk warning is issued to prompt the user that the electric vehicle has an unexpected acceleration risk.

[0014] Optionally, after restricting the required torque of the electric vehicle based on the unexpected acceleration risk degree index, the method further includes:

[0015] When the unexpected acceleration risk degree index is not greater than the first preset value, the restriction on the required torque of the electric vehicle is lifted.

[0016] Optionally, the step of lifting the restriction on the required torque of the electric vehicle when the unexpected acceleration risk degree index is not greater than the first preset value includes:

[0017] When the unexpected acceleration risk degree index is not greater than the first preset value, obtain the duration during which the unexpected acceleration risk degree index is not greater than the first preset value;

[0018] When the duration is greater than the preset time, set the unexpected acceleration risk degree index to zero;

[0019] When the unexpected acceleration risk degree index is zero, lift the restriction on the required torque of the electric vehicle.

[0020] Optionally, the step of restricting the required torque of the electric vehicle based on the unexpected acceleration risk degree index includes:

[0021] Restrict the change slope of the required torque of the electric vehicle based on the unexpected acceleration risk degree index.

[0022] Optionally, the step of restricting the required torque of the electric vehicle based on the unexpected acceleration risk degree index includes:

[0023] Determine the unexpected acceleration risk level according to the unexpected acceleration risk degree index;

[0024] Restrict the required torque of the electric vehicle based on the restriction method corresponding to the unexpected acceleration risk level.

[0025] Optionally, the step of determining the unexpected acceleration risk level according to the unexpected acceleration risk degree index includes:

[0026] When the unexpected acceleration risk index is greater than the first preset value and less than or equal to the second preset value, the unexpected acceleration risk level is determined to be the first level;

[0027] When the unexpected acceleration risk index is greater than the second preset value and less than or equal to the third preset value, the unexpected acceleration risk level is determined to be the second level;

[0028] When the unexpected acceleration risk index is greater than the third preset value, the unexpected acceleration risk level is determined to be the third level; wherein the first preset value is less than the second preset value, and the second preset value is less than the third preset value.

[0029] Optionally, the required torque is obtained by:

[0030] Based on the throttle characteristics of the electric vehicle, a table lookup calculation is performed to determine the required torque of the electric vehicle.

[0031] In a second aspect, the present application provides a torque control device for an electric vehicle, comprising:

[0032] A torque acquisition module, used to acquire the actual torque of the motor in the electric vehicle and acquire the required torque of the electric vehicle;

[0033] A difference judgment module, used to judge whether the difference between the required torque and the actual torque is greater than a preset difference;

[0034] An index calculation module, used for integrating the difference between the required torque and the actual torque according to a preset time length to obtain an unexpected acceleration risk index when the difference between the required torque and the actual torque is greater than a preset difference;

[0035] A torque limiting module is used to limit the required torque of the electric vehicle based on the unexpected acceleration risk index when the unexpected acceleration risk index is greater than a first preset value.

[0036] Optionally, the device further comprises:

[0037] The risk warning module is used to issue a risk warning when the unexpected acceleration risk index is greater than the first preset value to remind the user that the electric vehicle has an unexpected acceleration risk.

[0038] Optionally, the device further comprises: a restriction release module, which is used to release the restriction on the required torque of the electric vehicle when the unexpected acceleration risk index is not greater than a first preset value.

[0039] ​Optionally, the restriction release module is specifically configured to obtain the duration during which the non-expected acceleration risk degree index is not greater than the first preset value when the non-expected acceleration risk degree index is not greater than the first preset value; when the duration is greater than the preset time, clear the non-expected acceleration risk degree index; when the non-expected acceleration risk degree index is cleared, release the restriction on the required torque of the electric vehicle.

[0040] Optionally, the torque restriction module is specifically configured to restrict the change slope of the required torque of the electric vehicle based on the non-expected acceleration risk degree index.

[0041] Optionally, the torque restriction module is specifically configured to determine the non-expected acceleration risk level according to the non-expected acceleration risk degree index; and restrict the required torque of the electric vehicle based on the restriction method corresponding to the non-expected acceleration risk level.

[0042] Optionally, the torque restriction module is specifically configured to determine that the non-expected acceleration risk level is the first level when the non-expected acceleration risk degree index is greater than the first preset value and less than or equal to the second preset value; determine that the non-expected acceleration risk level is the second level when the non-expected acceleration risk degree index is greater than the second preset value and less than or equal to the third preset value; determine that the non-expected acceleration risk level is the third level when the non-expected acceleration risk degree index is greater than the third preset value; wherein, the first preset value is less than the second preset value, and the second preset value is less than the third preset value.

[0043] In a third aspect, the present application provides an electric vehicle, including a torque control device for an electric vehicle as described in the second aspect, to implement a torque control method for an electric vehicle as described in the first aspect.

[0044] Compared with the prior art, the present application has the following beneficial effects: Based on the integral of the difference between the required torque and the actual torque with respect to time, the non-expected acceleration risk degree index is obtained, and the non-expected acceleration risk degree index can represent the degree of non-expected acceleration risk of the current electric vehicle. And based on the non-expected acceleration risk degree index, the required torque of the electric vehicle is restricted to prevent non-expected acceleration, ensure the stability of the power output of the electric vehicle, thereby improving the driving experience and kinetic energy safety of the electric vehicle. Description of the Drawings

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0046] Figure 1 Schematic flow chart of a torque control method for an electric vehicle provided by an embodiment of the present application;

[0047] Figure 2 Waveform schematic diagram of a non - expected acceleration risk degree index provided by an embodiment of the present application;

[0048] Figure 3 Another waveform schematic diagram of a non - expected acceleration risk degree index provided by an embodiment of the present application;

[0049] Figure 4 Schematic structural diagram of a torque control device for an electric vehicle provided by an embodiment of the present application. Detailed implementation manners

[0050] As described above, in different scenarios, an electric vehicle may have different non - expected acceleration risks. For example, when the user continuously presses the accelerator pedal, the output demand torque may be limited by speed limits or other fault sources, resulting in the output torque at the wheel end of the electric vehicle being limited. When at a certain moment the demand torque is no longer limited by speed limits or other fault sources, there will be a non - expected acceleration risk. That is, the non - expected acceleration risk may cause the electric vehicle to suddenly accelerate, thus affecting the stability of the vehicle's power output, and thereby affecting the driving experience and functional safety of the electric vehicle.

[0051] The present application provides a torque control method for an electric vehicle, including: obtaining the actual torque of the motor in the electric vehicle and obtaining the demand torque of the electric vehicle; determining whether the difference between the demand torque and the actual torque is greater than a preset difference; when the difference between the demand torque and the actual torque is greater than the preset difference, integrating the difference between the demand torque and the actual torque according to a preset duration to obtain a non - expected acceleration risk degree index; when the non - expected acceleration risk degree index is greater than a first preset value, restricting the demand torque of the electric vehicle based on the non - expected acceleration risk degree index. By integrating the difference between the demand torque and the actual torque with respect to time to obtain the non - expected acceleration risk degree index, and restricting the demand torque of the electric vehicle based on the non - expected acceleration risk degree index to prevent non - expected acceleration, ensure the stability of the power output of the electric vehicle, and thereby improve the driving experience and kinetic safety of the electric vehicle.

[0052] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0053] Embodiment 1:

[0054] The following combines Figures 1-3 to introduce in detail a torque control method for an electric vehicle provided by an embodiment of the present application.

[0055] For the convenience of understanding, first, an example is given to introduce the scenarios with the risk of unexpected acceleration.

[0056] For the working condition where the driver continuously presses the accelerator pedal, due to the limitations of speed limits and other fault sources, the required torque of the electric vehicle is limited, that is, the actual torque does not meet the required torque of the electric vehicle. When the required torque is no longer limited at a certain moment, it will cause the electric vehicle to suddenly accelerate. Therefore, in this case, the electric vehicle has a risk of unexpected acceleration. In addition, when the required torque is not limited, but the components (such as the battery and motor) of the electric vehicle are in a limited state, when the components of the electric vehicle suddenly recover from the limited state, it will also cause the electric vehicle to suddenly accelerate. Therefore, in this case, the electric vehicle has a risk of unexpected acceleration.

[0057] For the working condition where the driver frequently releases and presses the accelerator pedal, due to the limitations of speed limits and other fault sources, the required torque of the electric vehicle is limited. When the required torque is no longer limited at a certain moment, it will cause the electric vehicle to suddenly accelerate. Therefore, in this case, the electric vehicle has a risk of unexpected acceleration.

[0058] For the working condition where the driver continuously releases the accelerator pedal, the electric vehicle is in a low-speed state. Due to fault source limitations or extreme limitations of component capabilities, etc., the creep mode (creeping mode, that is, the vehicle will slowly move without stepping on the accelerator pedal) of the electric vehicle will be prohibited. At a certain moment, when the fault source limitation disappears or the component capability recovers, the creep mode of the electric vehicle resumes, which will cause the electric vehicle to suddenly accelerate. Therefore, in this case, the electric vehicle has a risk of unexpected acceleration.

[0059] The specific process of a torque control method for an electric vehicle provided by an embodiment of the present application is as Figure 1 shown.

[0060] S101. Obtain the actual torque of the motor in the electric vehicle and obtain the required torque of the electric vehicle.

[0061] Among them, the actual torque of the motor in the electric vehicle is calculated based on parameters such as the current, inductance, and magnetic flux of the motor during the driving process of the electric vehicle.

[0062] Among them, the required torque of the electric vehicle is calculated based on parameters such as the gear state, accelerator pedal depth, and vehicle speed during the driving process of the electric vehicle.

[0063] In a possible implementation, based on the throttle characteristic (Pedal Map) of the electric vehicle, a look-up table calculation is performed to determine the required torque of the electric vehicle.

[0064] Among them, the throttle characteristic (Pedal Map) is the relationship between the throttle pedal depth, the engine speed, and the engine power. For an electric vehicle, the throttle characteristic is actually a relationship diagram of the required torque output by the motor at different throttles (i.e., different throttle pedal depths) and different vehicle speeds.

[0065] S102. Determine whether the difference between the required torque and the actual torque is greater than a preset difference.

[0066] When the difference between the required torque and the actual torque is not greater than the preset difference, it indicates that the electric vehicle does not have the risk of unexpected acceleration. It should be noted that even if the required torque of the electric vehicle is not restricted by any fault source and speed limit, during the operation of the motor (i.e., when outputting the actual torque), there will definitely be influences such as resistance and filtering, and there will be a small difference between the required torque and the actual torque, but it does not affect the normal driving of the electric vehicle.

[0067] Therefore, when the difference between the required torque and the actual torque is not greater than the preset difference, it indicates that the electric vehicle does not have the risk of unexpected acceleration, and there is no need to perform a torque control method for an electric vehicle provided in this embodiment of the application.

[0068] When the difference between the required torque and the actual torque is greater than the preset difference, it indicates that the electric vehicle has the risk of unexpected acceleration, and then S103 is performed.

[0069] S103. Integrate the difference between the required torque and the actual torque according to a preset duration to obtain an unexpected acceleration risk degree index.

[0070] Among them, the unexpected acceleration risk degree index can be used to characterize the possibility and degree of unexpected acceleration that may exist in the current electric vehicle.

[0071] Specifically, the unexpected acceleration risk degree index is obtained by integrating the difference between the required torque and the actual torque according to the following formula for a preset duration.

[0072] UAR = ∫(DrvrReqTq - ActTq)dt

[0073] Among them, UAR is the unexpected acceleration risk degree index, DrvrReqTq is the required torque of the electric vehicle, and ActTq is the actual torque of the motor of the electric vehicle.

[0074] In a possible implementation, the preset duration can be set to 200 ms. In addition, it can also be determined according to the actual situation, and the present application does not make specific limitations.

[0075] Specifically, integrating the difference between the required torque and the actual torque according to the preset duration can be as follows: obtaining the actual torque and the required torque every 1 ms, calculating the difference between the required torque and the actual torque, and recording it. After each update of the difference between the required torque and the actual torque, a new non-unexpected acceleration risk degree index is generated by integrating according to the latest difference between the torques and the differences between the torques within the preset duration recorded before. That is, the non-unexpected acceleration risk degree index is also updated according to the preset time.

[0076] Furthermore, the non-unexpected acceleration risk degree index (UAR) can be divided into the first non-unexpected acceleration risk degree index (SUAR) and the second non-unexpected acceleration risk degree index (LUAR). Among them, when the actual torque is lower than the preset torque, the SUAR starts to integrate. When the integration of the SUAR lasts for a certain period of time (for example: 10 ms), the LUAR starts to integrate. At this time, the non-unexpected acceleration risk degree index is the larger value between the first non-unexpected acceleration risk degree index (SUAR) and the second non-unexpected acceleration risk degree index (LUAR). Through the SUAR and the LUAR, misjudgment of the non-unexpected acceleration risk can be prevented.

[0077] For the convenience of understanding, the following combines Figure 2 and Figure 3 The two waveform diagrams shown to introduce the non-unexpected acceleration risk degree index by way of example.

[0078] As Figure 2 (a) shows the relationship between the actual torque and the required torque, which indicates that the required torque of the electric vehicle is not initially achieved (that is, the waveforms of the actual torque and the required torque do not overlap), and after a short period of time, the required torque of the electric vehicle is promptly satisfied (that is, the waveforms of the actual torque and the required torque tend to overlap). At this time, the numerical waveforms of the SUAR and the LUAR are as Figure 2 (b) shows. The value of the SUAR starts to increase from 0, approaches stability, and then quickly clears to zero. The value of the LUAR has not started to integrate, and the non-unexpected acceleration risk index is the larger value between the SUAR and the LUAR.

[0079] As Figure 3 (a) shows the relationship between the actual torque and the required torque, which indicates that initially the electric vehicle does not generate actual torque and the required torque of the electric vehicle is not achieved. After a relatively long period, the electric vehicle generates actual torque, and after a period of time when the electric vehicle starts to generate actual torque, the required torque of the electric vehicle is satisfied. At this time, the numerical waveforms of the SUAR and the LUAR are asFigure 3 As shown in (b), the SUAR starts to increase (integrate) before the LUAR and tends to stabilize. After a period of time after the SUAR starts to increase, the LUAR starts to increase (integrate) and also tends to stabilize, and the stable values of the LUAR and the SUAR are the same. When the demand torque is satisfied, the SUAR quickly resets to zero, while the LUAR resets to zero after a period of time lagging behind the SUAR. Then, the non-expected acceleration risk index is the larger value between the SUAR and the LUAR. Since the LUAR lags behind the SUAR, it can prevent misjudgment of the non-expected acceleration risk.

[0080] S104. When the non-expected acceleration risk degree index is greater than the first preset value, the demand torque of the electric vehicle is restricted based on the non-expected acceleration risk degree index.

[0081] Specifically, when the non-expected acceleration risk degree index is 0, it indicates that there is no non-expected acceleration risk in the current electric vehicle. The higher the non-expected acceleration risk degree index, the higher the non-expected acceleration risk of the electric vehicle.

[0082] In a possible implementation manner, the change slope of the demand torque of the electric vehicle is restricted based on the non-expected acceleration risk degree index. For example: when the non-expected acceleration risk degree index is greater than the first preset value, the greater the non-expected acceleration risk degree index, the stronger the restriction on the change slope of the demand torque of the electric vehicle. By restricting the change slope of the demand torque of the electric vehicle, the increase speed of the demand torque is restricted, that is, the greater the non-expected acceleration risk index, the smaller the change slope of the restricted demand torque, that is, the slower the increase speed of the demand torque.

[0083] By using the non-expected acceleration degree index to restrict the demand torque of the electric vehicle, that is, to realize the control of the torque of the electric vehicle, ensure the stable output of the torque of the electric vehicle, thereby maintaining the stability of the power output of the electric vehicle, and improving the driving experience and functional safety of the electric vehicle.

[0084] It should be noted that the non-expected acceleration risk degree index (UAR) has a hysteresis interval threshold to prevent the non-expected acceleration risk degree index from jumping, resulting in the repeated enabling and disabling of the non-expected acceleration function. Among them, the first preset value is actually the lower limit of the hysteresis interval threshold of the non-expected acceleration risk degree index. Specifically, when the non-expected acceleration risk degree index is greater than the upper limit of the hysteresis interval threshold, the demand torque restriction function is enabled; when the non-expected acceleration risk degree index is less than the upper limit of the hysteresis interval threshold but greater than the lower limit of the hysteresis interval threshold (the first preset value), the demand torque restriction function remains enabled until the non-expected acceleration risk degree index is not greater than the lower limit of the hysteresis interval threshold (the first preset value), and the demand torque restriction function is exited.

[0085] Further, in a possible implementation, when the unexpected acceleration risk degree index is greater than the first preset value, the unexpected acceleration risk level is determined according to the unexpected acceleration risk degree index, and the required torque of the electric vehicle is limited based on the limiting method corresponding to the unexpected acceleration risk level.

[0086] Specifically, when the unexpected acceleration risk degree index is greater than the first preset value and less than or equal to the second preset value, it is determined that the unexpected acceleration risk level is the first level; when the unexpected acceleration risk degree index is greater than the second preset value and less than or equal to the third preset value, it is determined that the unexpected acceleration risk level is the second level; when the unexpected acceleration risk degree index is greater than the third preset value, it is determined that the unexpected acceleration risk level is the third level. Among them, the first preset value is less than the second preset value, and the second preset value is less than the third preset value. For example: when the unexpected acceleration risk level is the first level, the required torque of the electric vehicle is limited by using the limiting method corresponding to the first level.

[0087] Further, when the unexpected acceleration degree index is greater than the first preset value, a risk warning is issued to prompt the user that the electric vehicle has an unexpected acceleration risk. Thus, the function of timely reminder is realized.

[0088] Further, after limiting the required torque of the electric vehicle based on the unexpected acceleration risk degree index, the actual torque of the motor in the electric vehicle and the required torque of the electric vehicle are obtained in real time; and based on the difference between the actually obtained real-time torque and the required torque, the unexpected acceleration risk degree index is updated; when the updated unexpected acceleration risk degree index is greater than the preset value, the required torque of the electric vehicle is limited based on the updated unexpected acceleration risk degree index. Thus, the real-time limitation of the required torque of the electric vehicle is realized, so as to ensure the smooth driving of the electric vehicle.

[0089] Further, after limiting the required torque of the electric vehicle based on the unexpected acceleration risk degree index, when the unexpected acceleration risk degree index is not greater than the first preset value, the limitation of the required torque of the electric vehicle is released, so as to restore the output power of the electric vehicle.

[0090] In a possible implementation, when the unexpected acceleration risk degree index is not greater than the first preset value, the duration during which the unexpected acceleration risk degree index is not greater than the first preset value is obtained. When the duration is greater than the preset time, the unexpected acceleration risk degree index is cleared. When the unexpected acceleration risk degree index is cleared, the limitation of the required torque of the electric vehicle is released, so as to restore the output power of the electric vehicle.

[0091] An embodiment of the present application provides a torque control method for an electric vehicle, including: obtaining the actual torque of the motor in the electric vehicle and obtaining the required torque of the electric vehicle; determining whether the difference between the required torque and the actual torque is greater than a preset difference; when the difference between the required torque and the actual torque is greater than the preset difference, integrating the difference between the required torque and the actual torque according to a preset duration to obtain an unexpected acceleration risk degree index; when the unexpected acceleration risk degree index is greater than a first preset value, restricting the required torque of the electric vehicle based on the unexpected acceleration risk degree index. By integrating the difference between the required torque and the actual torque over time, an unexpected acceleration risk degree index is obtained, and the required torque of the electric vehicle is restricted based on the unexpected acceleration risk degree index to prevent unexpected acceleration and ensure the stability of the power output of the electric vehicle, thereby improving the driving experience and kinetic energy safety of the electric vehicle.

[0092] Further, when the unexpected acceleration degree index is greater than the first preset value, a risk warning is issued to prompt the user that the electric vehicle has an unexpected acceleration risk, so as to realize the function of timely reminder.

[0093] Further, when the unexpected acceleration degree index is not greater than the first preset value, the restriction on the required torque of the electric vehicle is lifted, thereby restoring the output power of the electric vehicle.

[0094] Embodiment 2:

[0095] The following combines Figure 4 , and details an electric vehicle torque control device provided by an embodiment of the present application.

[0096] A torque acquisition module 401 is configured to acquire the actual torque of the motor in the electric vehicle and acquire the required torque of the electric vehicle;

[0097] A difference judgment module 402 is configured to determine whether the difference between the required torque and the actual torque is greater than a preset difference;

[0098] An index calculation module 403 is configured to, when the difference between the required torque and the actual torque is greater than a preset difference, integrate the difference between the required torque and the actual torque according to a preset duration to obtain an unexpected acceleration risk degree index;

[0099] A torque restriction module 404 is configured to, when the unexpected acceleration risk degree index is greater than a first preset value, restrict the required torque of the electric vehicle based on the unexpected acceleration risk degree index.

[0100] Further, the device further includes: a risk warning module, configured to issue a risk warning when the unexpected acceleration risk index is greater than the first preset value to prompt the user that the electric vehicle has an unexpected acceleration risk.

[0101] Further, the device further includes: a restriction release module, configured to release the restriction on the required torque of the electric vehicle when the non-expected acceleration risk degree index is not greater than a first preset value.

[0102] Further, the restriction release module is specifically configured to, when the non-expected acceleration risk degree index is not greater than a first preset value, obtain the duration for which the non-expected acceleration risk degree index is not greater than the first preset value; when the duration is greater than a preset time, clear the non-expected acceleration risk degree index; and when the non-expected acceleration risk degree index is cleared, release the restriction on the required torque of the electric vehicle.

[0103] Further, the torque restriction module 404 is specifically configured to restrict the change slope of the required torque of the electric vehicle based on the non-expected acceleration risk degree index.

[0104] Further, the torque restriction module 404 is specifically configured to determine the non-expected acceleration risk level according to the non-expected acceleration risk degree index; and restrict the required torque of the electric vehicle based on the restriction method corresponding to the non-expected acceleration risk level.

[0105] Further, the torque restriction module 404 is specifically configured to, when the non-expected acceleration risk degree index is greater than a first preset value and less than or equal to a second preset value, determine that the non-expected acceleration risk level is a first level; when the non-expected acceleration risk degree index is greater than the second preset value and less than or equal to a third preset value, determine that the non-expected acceleration risk level is a second level; and when the non-expected acceleration risk degree index is greater than the third preset value, determine that the non-expected acceleration risk level is a third level; where the first preset value is less than the second preset value, and the second preset value is less than the third preset value.

[0106] An embodiment of the present application provides a torque control device for an electric vehicle, including: a torque acquisition module 401, configured to acquire the actual torque of a motor in the electric vehicle and acquire the required torque of the electric vehicle; a difference judgment module 402, configured to judge whether the difference between the required torque and the actual torque is greater than a preset difference; an index calculation module 403, configured to, when the difference between the required torque and the actual torque is greater than the preset difference, integrate the difference between the required torque and the actual torque according to a preset duration to obtain a non-expected acceleration risk degree index; and a torque restriction module 404, configured to, when the non-expected acceleration risk degree index is greater than a first preset value, restrict the required torque of the electric vehicle based on the non-expected acceleration risk degree index. By integrating the difference between the required torque and the actual torque over time, a non-expected acceleration risk degree index is obtained, and the required torque of the electric vehicle is restricted based on the non-expected acceleration risk degree index to prevent non-expected acceleration, ensure the stability of the power output of the electric vehicle, and thus improve the driving experience and kinetic energy safety of the electric vehicle.

[0107] Further, when the unexpected acceleration degree index is greater than the first preset value, a risk warning is given to prompt the user that there is a risk of unexpected acceleration in the electric vehicle, thus realizing the function of timely reminder.

[0108] Further, when the unexpected acceleration degree index is not greater than the first preset value, the limitation on the demand torque of the electric vehicle is released, thereby restoring the output power of the electric vehicle.

[0109] It should be noted that each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the method and device embodiments, since they are basically similar to the method embodiments, they are described relatively simply, and the relevant parts can be referred to the description of the method embodiments. The device and system embodiments described above are only illustrative. The units described as separate components may or may not be physically separated, and the components prompted as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative work.

[0110] The above is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A torque control method for an electric vehicle, characterized in that: include: Obtaining an actual torque of a motor in an electric vehicle, and obtaining a required torque of the electric vehicle; Determining whether a difference between the required torque and the actual torque is greater than a preset difference; When the difference between the required torque and the actual torque is greater than a preset difference, the difference between the required torque and the actual torque is integrated according to a preset time period to obtain an unexpected acceleration risk degree index; When the unexpected acceleration risk level index is greater than a first preset value, the demand torque of the electric vehicle is limited based on the unexpected acceleration risk level index.

2. The method according to claim 1, characterized in that The method further comprises: When the unexpected acceleration risk index is greater than the first preset value, a risk warning is issued to remind the user that the electric vehicle has an unexpected acceleration risk.

3. The method according to claim 1, characterized in that After limiting the required torque of the electric vehicle based on the unexpected acceleration risk index, the method further includes: When the unexpected acceleration risk index is not greater than the first preset value, the restriction on the required torque of the electric vehicle is released.

4. The method according to claim 3, characterized in that When the unexpected acceleration risk index is not greater than the first preset value, releasing the restriction on the required torque of the electric vehicle includes: When the unexpected acceleration risk level index is not greater than the first preset value, obtaining a duration during which the unexpected acceleration risk level index is not greater than the first preset value; When the duration is greater than a preset time, the unexpected acceleration risk index is reset to zero; When the unexpected acceleration risk level index is cleared to zero, the restriction on the required torque of the electric vehicle is released.

5. The method according to claim 1, characterized in that The limiting the required torque of the electric vehicle based on the unexpected acceleration risk index includes: Based on the unexpected acceleration risk level index, a change slope of the required torque of the electric vehicle is limited.

6. The method according to claim 1, characterized in that: The limiting the required torque of the electric vehicle based on the unexpected acceleration risk index includes: Determining the unexpected acceleration risk level according to the unexpected acceleration risk degree index; The required torque of the electric vehicle is limited based on a limitation method corresponding to the unexpected acceleration risk level.

7. The method according to claim 6, characterized in that Determining the unexpected acceleration risk level according to the unexpected acceleration risk index includes: When the unexpected acceleration risk index is greater than the first preset value and less than or equal to a second preset value, determining that the unexpected acceleration risk level is the first level; When the unexpected acceleration risk index is greater than the second preset value and less than or equal to a third preset value, determining that the unexpected acceleration risk level is the second level; When the unexpected acceleration risk index is greater than the third preset value, the unexpected acceleration risk level is determined to be the third level; wherein the first preset value is less than the second preset value, and the second preset value is less than the third preset value.

8. The method according to any one of claims 1 to 7, characterized in that: The required torque is obtained as follows: Based on the throttle characteristics of the electric vehicle, a table lookup calculation is performed to determine the required torque of the electric vehicle.

9. A torque control device for an electric vehicle, characterized in that: include: A torque acquisition module, used to acquire the actual torque of the motor in the electric vehicle and acquire the required torque of the electric vehicle; A difference judgment module, used to judge whether the difference between the required torque and the actual torque is greater than a preset difference; an index calculation module, configured to integrate the difference between the required torque and the actual torque according to a preset time period to obtain an unexpected acceleration risk index when the difference between the required torque and the actual torque is greater than a preset difference; The torque limiting module is used to limit the required torque of the electric vehicle based on the unexpected acceleration risk index when the unexpected acceleration risk index is greater than a first preset value.

10. The device according to claim 9, characterized in that The device also includes: The risk warning module is used to issue a risk warning when the unexpected acceleration risk index is greater than the first preset value to prompt the user that the electric vehicle has an unexpected acceleration risk.

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