A vehicle torque control method and device

Abstract

This invention discloses a vehicle torque control method and apparatus. The method includes: determining the actual output torque value based on the driving state of the electric vehicle during operation; calculating the difference between the actual output torque value and the vehicle's limit torque value; determining a torque adjustment gradient value based on the difference; and adjusting the required torque value of the electric vehicle based on the torque adjustment gradient value. The vehicle torque control scheme disclosed in this invention can reduce the duration and frequency of continuous vehicle vibration, thereby improving the driving experience.

Description

Technical Field

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

[0002] Automotive torque reflects the torque output from the crankshaft when the engine is running. Simply put, it's the amount of force the engine can generate per revolution; the greater the torque, the greater the engine's force. To ensure vehicle stability during driving, torque filtering methods are used to control torque in specific situations such as acceleration and deceleration, allowing for smooth driving during gear changes. Existing torque filtering methods only have a single torque filtering coefficient. When the actual output torque approaches or exceeds the vehicle's permissible torque limit, the driver's required torque is suddenly restricted, causing a sudden decrease in the vehicle's actual output torque and resulting in wheel vibration. Since there's a conversion relationship between wheel speed and torque limit, fluctuations in wheel speed further affect torque limit fluctuations, ultimately causing continuous vehicle vibration and impacting the overall driving experience. Summary of the Invention

[0003] The purpose of this invention is to provide a vehicle torque control method and system that can solve the problem of continuous vehicle vibration caused by the actual output torque of the vehicle being limited by the allowable torque limit value of the vehicle in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] This invention provides a vehicle torque control method applied to electric vehicles, the method comprising:

[0006] During the operation of an electric vehicle, the actual output torque value is determined based on the vehicle's driving status.

[0007] Calculate the difference between the actual output torque value and the vehicle's limit torque value;

[0008] The torque adjustment gradient value is determined based on the difference.

[0009] The actual output torque value of the electric vehicle is adjusted based on the torque adjustment gradient value.

[0010] Optionally, the step of determining the torque adjustment gradient value based on the difference includes:

[0011] The torque adjustment gradient value corresponding to the difference is found from the preset gradient value list; wherein, the gradient value list includes the relationship between the difference range and the gradient value.

[0012] or,

[0013] Determine the sign of the difference;

[0014] Find the list of gradient values ​​corresponding to the positive or negative value of the difference, and determine the torque adjustment gradient value corresponding to the difference.

[0015] Optionally, the step of adjusting the actual output torque value of the electric vehicle based on the torque adjustment gradient value includes:

[0016] When the wheel speed of the electric vehicle is shuddering downwards, the sum of the torque adjustment gradient value and the required torque value at the previous moment is determined as the actual output torque value of the electric vehicle.

[0017] When the wheel speed of the electric vehicle vibrates upwards, the difference between the required torque value at the previous moment and the torque adjustment gradient value is determined as the actual output torque value of the electric vehicle.

[0018] Optionally, the step of adjusting the actual output torque value of the electric vehicle based on the torque adjustment gradient value includes:

[0019] When the wheel speed of the electric vehicle is shuddering downwards, the sum of the torque adjustment gradient value and the actual output torque value is determined as the actual output torque value of the electric vehicle.

[0020] When the wheel speed of the electric vehicle vibrates upwards, the difference between the actual output torque value and the torque adjustment gradient value is determined as the actual output torque value of the electric vehicle.

[0021] Optionally, the correspondence between the difference range and the gradient value in the preset gradient value list is fixed data, which is manually set by the user; or,

[0022] The correspondence between the difference range and the gradient value in the preset gradient value list is dynamically adjusted based on the torque control strategy during the historical driving process of the electric vehicle.

[0023] This invention also provides a vehicle torque control device for electric vehicles, the device comprising:

[0024] The first determining module is used to determine the actual output torque value based on the driving state of the electric vehicle during driving.

[0025] The calculation module is used to calculate the difference between the actual output torque value and the vehicle's limited torque value;

[0026] The second determining module is used to determine the torque adjustment gradient value based on the difference;

[0027] An adjustment module is used to adjust the actual output torque value of the electric vehicle based on the torque adjustment gradient value.

[0028] Optionally, the first determining module includes:

[0029] The first submodule is used to find the torque adjustment gradient value corresponding to the difference from a preset gradient value list; wherein, the gradient value list includes: the correspondence between the difference range and the gradient value;

[0030] or,

[0031] The second submodule is used to determine the sign of the difference; search the gradient value list corresponding to the sign of the difference, and determine the torque adjustment gradient value corresponding to the difference.

[0032] Optionally, the adjustment module includes:

[0033] The third submodule is used to determine the actual output torque value of the electric vehicle by summing the torque adjustment gradient value with the demand torque value at the previous moment when the wheel speed of the electric vehicle is shaking downward.

[0034] The fourth submodule is used to determine the difference between the required torque value at the previous moment and the torque adjustment gradient value as the actual output torque value of the electric vehicle when the wheel speed of the electric vehicle is shaking upward.

[0035] Optionally, the adjustment module includes:

[0036] The fifth submodule is used to determine the actual output torque value of the electric vehicle by summing the torque adjustment gradient value and the actual output torque value when the wheel speed of the electric vehicle is shaking downward.

[0037] The sixth submodule is used to determine the difference between the actual output torque value and the torque adjustment gradient value as the actual output torque value of the electric vehicle when the wheel speed of the electric vehicle vibrates upward.

[0038] Optionally, the correspondence between the difference range and the gradient value in the preset gradient value list is fixed data that is manually set by the user; or, the correspondence between the difference range and the gradient value in the preset gradient value list is dynamically adjusted based on the torque control strategy during the historical driving process of the electric vehicle.

[0039] The vehicle torque control scheme provided in this invention determines the actual output torque value based on the driving state of the electric vehicle during operation; calculates the difference between the actual output torque value and the vehicle's limit torque value; determines a torque adjustment gradient value based on the difference; and adjusts the actual output torque of the electric vehicle based on the torque adjustment gradient value. This vehicle torque control scheme distinguishes between the gradient limits for increasing and decreasing demand torque. When wheel speed vibrates, it can effectively suppress the passive vibration of the demand torque, thereby indirectly suppressing the drivability problem caused by overall wheel speed vibration. Attached Figure Description

[0040] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1 This is a schematic flowchart illustrating a vehicle torque control method according to an embodiment of this application;

[0042] Figure 2 This is a schematic diagram illustrating the effect of torque control in existing technologies;

[0043] Figure 3 This is a schematic diagram illustrating the effect of torque control achieved by the method shown in the embodiments of this application;

[0044] Figure 4 This is a structural block diagram illustrating a vehicle torque control device according to an embodiment of this application. Detailed Implementation

[0045] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0046] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0047] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0048] The vehicle torque control scheme provided in this application can suppress the driving performance problem of continuous vehicle vibration caused by the actual output torque being limited by the vehicle's allowable torque limit. When the actual output torque approaches or exceeds the vehicle's allowable torque limit, by distinguishing the gradient limits of the increase and decrease of the driver's required torque, the driver's required torque achieves the effect of decreasing quickly and increasing slowly, thereby suppressing the problem of vehicle vibration caused by the fluctuation of required torque.

[0049] The vehicle torque control scheme provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0050] As attached Figure 1 As shown, the vehicle torque control method of this application embodiment includes the following steps:

[0051] Step 101: During the operation of the electric vehicle, determine the actual output torque value based on the driving status of the electric vehicle.

[0052] The vehicle torque control method provided in this application is applied to electric vehicles, which can be either pure electric vehicles or hybrid vehicles. The actual output torque value can be determined in real time by the electric vehicle's power control system during operation. The actual output torque value can be derived from the current engine power.

[0053] Step 102: Calculate the difference between the actual output torque value and the vehicle's limit torque value.

[0054] The power control system of an electric vehicle has a preset limit torque value. When the vehicle torque just begins to change, it is adjusted with reference to the preset limit torque value in the system. During the adjustment process, the vehicle limit torque value changes, so each torque adjustment is based on the previously adjusted vehicle limit torque value for the next torque adjustment.

[0055] Appendix Figure 3 This is a schematic diagram illustrating the effect of torque control using the vehicle torque control method provided in the embodiments of this application. (See attached diagram.) Figure 3 As can be seen, the unfiltered demand torque remains unchanged, while the actual output torque after being limited by the torque limit value changes during the control process, and the torque limit value also changes during the torque control process.

[0056] Step 103: Determine the torque adjustment gradient value based on the difference.

[0057] Alternatively, the torque adjustment gradient value can be determined based on the difference as follows:

[0058] Method 1: Find the torque adjustment gradient value corresponding to the difference from the preset gradient value list; whereby the gradient value list includes the relationship between the difference range and the gradient value.

[0059] In actual implementation, after calculating the difference, the target difference range to which the difference belongs is found from the preset gradient value list. The gradient value corresponding to the target difference range is then determined as the torque adjustment gradient value. The specific correspondence between the difference range and the gradient value can be set by those skilled in the art based on experimental results or experience; this application embodiment does not impose specific limitations on this.

[0060] or,

[0061] Method 2: Determine the sign of the difference; find the list of gradient values ​​corresponding to the sign of the difference, and determine the torque adjustment gradient value corresponding to the difference.

[0062] The sign of the difference indicates whether the wheel speed of the electric vehicle is fluctuating upwards or downwards. When the wheel speed fluctuates downwards, the corresponding torque adjustment gradient value is positive, indicating that the torque value needs to be increased; conversely, it indicates that the torque value needs to be decreased. In Method Two, two gradient value lists are pre-set: one list corresponds to the gradient value corresponding to the difference determined when the wheel speed fluctuates downwards; the other list corresponds to the gradient value corresponding to the difference determined when the wheel speed fluctuates upwards.

[0063] The correspondence between the difference range and the gradient value in the preset gradient value list is fixed data that can be manually set by the user; or, the correspondence between the difference range and the gradient value in the preset gradient value list is dynamically adjusted based on the torque control strategy during the electric vehicle's historical driving process.

[0064] It should be noted that the above are only two feasible ways to generate data in the preset gradient value list. In actual implementation, it is not limited to these methods. Those skilled in the art can set the generation method of the preset gradient value list according to actual needs. For example, the correspondence between the difference range and the gradient value can also be determined based on a large amount of experimental test data.

[0065] Step 104: Adjust the actual output torque value of the electric vehicle based on the torque adjustment gradient value.

[0066] An optional method for adjusting the actual output torque of an electric vehicle based on a torque adjustment gradient value is as follows:

[0067] When the wheel speed of an electric vehicle is oscillating downwards, the sum of the torque adjustment gradient value and the demand torque value at the previous moment is determined as the actual output torque value of the electric vehicle; when the wheel speed of an electric vehicle is oscillating upwards, the difference between the demand torque value at the previous moment and the torque adjustment gradient value is determined as the actual output torque value of the electric vehicle.

[0068] Another alternative method to adjust the actual output torque of an electric vehicle based on the torque adjustment gradient value is as follows:

[0069] When the wheel speed of an electric vehicle is downward, the sum of the torque adjustment gradient value and the actual output torque value is determined as the actual output torque value of the electric vehicle; when the wheel speed of an electric vehicle is upward, the difference between the actual output torque value and the torque adjustment gradient value is determined as the actual output torque value of the electric vehicle.

[0070] During the operation of an electric vehicle, the vehicle torque control method provided in this application embodiment can effectively suppress the frequency of wheel speed vibration and effectively shorten the duration of wheel speed vibration compared to the torque filtering method provided in the prior art. Figure 2 A schematic diagram illustrating the effect of torque control in existing technologies is attached. Figure 2 The existing technical solution shown, when the actual output torque approaches or exceeds the allowable torque limit of the vehicle, has only a single torque filtering coefficient. When the torque is limited and reduced, it causes the wheel speed to vibrate. Since there is a certain conversion relationship between wheel speed and torque limit, the fluctuation of wheel speed will in turn affect the vibration of torque limit. The vibration of torque limit will cause the actual output torque to vibrate with almost the same period, amplitude, and different phases, which will directly aggravate the wheel speed vibration problem. As a result, the vibration of the whole vehicle lasts for a long time from t1 to t2, and the vibration problem of the whole vehicle can be clearly perceived.

[0071] Figure 3 This is a schematic diagram illustrating the effect of torque control achieved by the method shown in the embodiments of this application, as shown in the attached diagram. Figure 3 As shown, the torque control method provided in this application distinguishes between the gradient limits of the increase and decrease of the required torque. It uses the difference between the actual output torque and the vehicle's limit torque value to look up the gradient limit values, i.e., the torque adjustment gradient values. When the wheel speed vibrates downwards, the vehicle's torque limit value fluctuates upwards, but the required torque is limited to a small growth gradient by the increasing gradient. This effectively suppresses the passive vibration of the actual output torque, thereby indirectly suppressing the vibration of the vehicle's wheel speed. Compared to... Figure 3 The duration of vibration can be effectively shortened from t1 to t2 (i.e., the duration of vehicle vibration), and the problem of vehicle vibration can be significantly improved.

[0072] The vehicle torque control method provided in this application determines the actual output torque value based on the driving state of the electric vehicle during operation; calculates the difference between the actual output torque value and the vehicle's limit torque value; determines a torque adjustment gradient value based on the difference; and adjusts the actual output torque of the electric vehicle based on the torque adjustment gradient value. The vehicle torque control scheme proposed in this invention distinguishes between the gradient limits for rising and falling demand torque. When wheel speed vibrates, it can effectively suppress the passive vibration of the demand torque, thereby indirectly suppressing the drivability problem caused by overall wheel speed vibration.

[0073] Figure 4 The structural block diagram of a vehicle torque control device according to an embodiment of this application is shown.

[0074] The vehicle torque control device of this application embodiment is applied to an electric vehicle, and the device includes the following functional modules:

[0075] The first determining module 401 is used to determine the actual output torque value based on the driving state of the electric vehicle during driving.

[0076] Calculation module 402 is used to calculate the difference between the actual output torque value and the vehicle's limited torque value;

[0077] The second determining module 403 is used to determine the torque adjustment gradient value based on the difference;

[0078] The adjustment module 404 is used to adjust the actual output torque value of the electric vehicle based on the torque adjustment gradient value.

[0079] Optionally, the first determining module includes:

[0080] The first submodule is used to find the torque adjustment gradient value corresponding to the difference from a preset gradient value list; wherein, the gradient value list includes: the correspondence between the difference range and the gradient value;

[0081] or,

[0082] The second submodule is used to determine the sign of the difference; search the gradient value list corresponding to the sign of the difference, and determine the torque adjustment gradient value corresponding to the difference.

[0083] Optionally, the adjustment module includes:

[0084] The third submodule is used to determine the actual output torque value of the electric vehicle by summing the torque adjustment gradient value with the demand torque value at the previous moment when the wheel speed of the electric vehicle is shaking downward.

[0085] The fourth submodule is used to determine the difference between the required torque value at the previous moment and the torque adjustment gradient value as the actual output torque value of the electric vehicle when the wheel speed of the electric vehicle is shaking upward.

[0086] Optionally, the adjustment module includes:

[0087] The fifth submodule is used to determine the actual output torque value of the electric vehicle by summing the torque adjustment gradient value and the actual output torque value when the wheel speed of the electric vehicle is shaking downward.

[0088] The sixth submodule is used to determine the difference between the actual output torque value and the torque adjustment gradient value as the actual output torque value of the electric vehicle when the wheel speed of the electric vehicle vibrates upward.

[0089] Optionally, the correspondence between the difference range and the gradient value in the preset gradient value list is fixed data, which is manually set by the user; or,

[0090] The correspondence between the difference range and the gradient value in the preset gradient value list is dynamically adjusted based on the torque control strategy during the historical driving process of the electric vehicle.

[0091] The vehicle torque control device provided in the application embodiment determines the actual output torque value based on the driving state of the electric vehicle during operation; calculates the difference between the actual output torque value and the vehicle's limit torque value; determines a torque adjustment gradient value based on the difference; and adjusts the actual output torque of the electric vehicle based on the torque adjustment gradient value. The vehicle torque control device proposed in this embodiment distinguishes between the gradient limits for rising and falling demand torque. When wheel speed vibrates, it can effectively suppress passive vibration of the demand torque, thereby indirectly suppressing the drivability problem caused by overall wheel speed vibration.

[0092] The embodiments provided in this application Figure 4 The vehicle torque control device shown can achieve Figure 1 The various processes implemented in the method implementation examples will not be described again here to avoid repetition.

[0093] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0094] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A vehicle torque control method, applied to electric vehicles, characterized in that, include: During the operation of an electric vehicle, the actual output torque value is determined based on the vehicle's driving status. Calculate the difference between the actual output torque value and the vehicle's limit torque value; The torque adjustment gradient value is determined based on the difference. The actual output torque value of the electric vehicle is adjusted according to the torque adjustment gradient value. The step of determining the torque adjustment gradient value based on the difference includes: The torque adjustment gradient value corresponding to the difference is found from the preset gradient value list; wherein, the gradient value list includes the relationship between the difference range and the gradient value. or, Determine the sign of the difference; Search the list of gradient values ​​corresponding to the sign of the difference to determine the torque adjustment gradient value corresponding to the difference; The step of adjusting the actual output torque value of the electric vehicle based on the torque adjustment gradient value includes: When the wheel speed of the electric vehicle is shuddering downwards, the sum of the torque adjustment gradient value and the required torque value at the previous moment is determined as the actual output torque value of the electric vehicle. When the wheel speed of the electric vehicle vibrates upwards, the difference between the required torque value at the previous moment and the torque adjustment gradient value is determined as the actual output torque value of the electric vehicle.

2. The method according to claim 1, characterized in that, The step of adjusting the actual output torque value of the electric vehicle based on the torque adjustment gradient value includes: When the wheel speed of the electric vehicle is shuddering downwards, the sum of the torque adjustment gradient value and the actual output torque value is determined as the actual output torque value of the electric vehicle. When the wheel speed of the electric vehicle vibrates upwards, the difference between the actual output torque value and the torque adjustment gradient value is determined as the actual output torque value of the electric vehicle.

3. The method according to claim 1, characterized in that: The correspondence between the difference range and the gradient value in the preset gradient value list is fixed data, which is manually set by the user; or... The correspondence between the difference range and the gradient value in the preset gradient value list is dynamically adjusted based on the torque control strategy during the historical driving process of the electric vehicle.

4. A vehicle torque control device, applied to an electric vehicle, characterized in that, For implementing the vehicle torque control method according to any one of claims 1 to 3, the apparatus comprises: The first determining module is used to determine the actual output torque value based on the driving state of the electric vehicle during driving. The calculation module is used to calculate the difference between the actual output torque value and the vehicle's limited torque value; The second determining module is used to determine the torque adjustment gradient value based on the difference; An adjustment module is used to adjust the actual output torque value of the electric vehicle based on the torque adjustment gradient value.

5. The apparatus according to claim 4, characterized in that, The first determining module includes: The first submodule is used to find the torque adjustment gradient value corresponding to the difference from a preset gradient value list; wherein, the gradient value list includes: the correspondence between the difference range and the gradient value; or, The second submodule is used to determine the sign of the difference; search the gradient value list corresponding to the sign of the difference, and determine the torque adjustment gradient value corresponding to the difference.

6. The apparatus according to claim 4, characterized in that, The adjustment module includes: The third submodule is used to determine the actual output torque value of the electric vehicle by summing the torque adjustment gradient value with the demand torque value at the previous moment when the wheel speed of the electric vehicle is shaking downward. The fourth submodule is used to determine the difference between the required torque value at the previous moment and the torque adjustment gradient value as the actual output torque value of the electric vehicle when the wheel speed of the electric vehicle is shaking upward.

7. The apparatus according to claim 4, characterized in that, The adjustment module includes: The fifth submodule is used to determine the actual output torque value of the electric vehicle by summing the torque adjustment gradient value and the actual output torque value when the wheel speed of the electric vehicle is shaking downward. The sixth submodule is used to determine the difference between the actual output torque value and the torque adjustment gradient value as the actual output torque value of the electric vehicle when the wheel speed of the electric vehicle vibrates upward.

8. The apparatus according to claim 4, characterized in that: The correspondence between the difference range and the gradient value in the preset gradient value list is fixed data, which is manually set by the user; or... The correspondence between the difference range and the gradient value in the preset gradient value list is dynamically adjusted based on the torque control strategy during the historical driving process of the electric vehicle.

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