Shift control method and apparatus for electric vehicle transmission

Abstract

The invention relates to a gear shifting control method for a gearbox of an electric vehicle. The method comprises the steps that first information related to the state of the vehicle and second information related to a driving scene are received; in the gear shifting period, the rotating speed difference variable quantity between a gear ring and a shaft sleeve in the gearbox is determined according to the first information and the second information; and determining a target rotating speed of a control motor based on the rotating speed difference variable quantity and a rotating speed difference basic value between the gear ring and the shaft sleeve, wherein the control motor is used for controlling the gearbox. The application also relates to a shift control device for an electric vehicle gearbox, a computer storage medium, a computer program product, and a multi-speed gearbox controller for an electric vehicle.

Description

Technical Field

[0001] The present application relates to the field of shift control of electric vehicle transmissions, and more specifically, to a shift control method and device for electric vehicle transmissions, a computer storage medium, a computer program product, and a multi-speed transmission controller for electric vehicles. Background Art

[0002] As electric vehicles continue to develop, their technical performance is also constantly improving. As far as the most important powertrain system is concerned, a single-speed transmission (or single-speed gearbox) has the advantages of simple structure, low cost, and low failure rate, but due to the fixed speed ratio, in order to avoid motor overspeeding, the maximum speed of the vehicle will also be limited. In addition, the single-speed transmission has average acceleration ability in the middle and later stages when the vehicle is driving at high speed. Compared with a single-speed transmission with a fixed speed ratio, a multi-speed transmission (or multi-speed gearbox) can be adjusted by gear position, such as using a high-speed ratio in the first gear to provide high torque at startup and using a small speed ratio in the second gear to increase the maximum speed of the vehicle. At the same time, the reduction in motor speed helps to improve the NVH performance of the entire vehicle, and by controlling the shifting strategy, the motor can also work more in the high-efficiency range, thereby reducing energy consumption and increasing cruising range.

[0003] However, the use of multi-speed transmissions also has the following problems: under certain special working conditions (such as when the vehicle is fully loaded and going up or down a steep slope), the shifting of electric vehicles often fails and triggers the software fault handling mode. In addition, the overall shifting shock increases and the shifting quality decreases. Summary of the invention

[0004] According to one aspect of the present application, a shift control method for an electric vehicle transmission is provided, the method comprising: receiving first information related to a vehicle state and second information related to a driving scenario; during shifting, determining a change in speed difference between a ring gear and a sleeve in the transmission according to the first information and the second information; and determining a target speed of a control motor based on the change in speed difference and a base value of the speed difference between the ring gear and the sleeve, wherein the control motor is used to control the transmission.

[0005] As a supplement or alternative to the above solution, in the above method, the first information related to the vehicle state is the weight of the electric vehicle; and the second information related to the driving scene is the slope.

[0006] As a supplement or alternative to the above scheme, in the above method, the gear shifting period includes a torque reduction stage, a gear disengagement stage, a motor speed regulation stage, a gear engagement stage and a torque recovery stage.

[0007] As a supplement or alternative to the above solution, the above method may further include: controlling the motor by utilizing the target speed request.

[0008] As a supplement or alternative to the above solution, in the above method, the rotation speed of the ring gear is obtained by an input shaft rotation speed sensor, and the rotation speed of the sleeve is obtained by an output shaft rotation speed sensor.

[0009] According to another aspect of the present application, a shift control device for an electric vehicle gearbox is provided, the device comprising: a receiving device for receiving first information related to a vehicle state and second information related to a driving scenario; a first determining device for determining, during a gear shift, a change in the speed difference between a ring gear and a sleeve in the gearbox based on the first information and the second information; and a second determining device for determining a target speed of a control motor based on the change in the speed difference and a base value of the speed difference between the ring gear and the sleeve, wherein the control motor is used to control the gearbox.

[0010] As a supplement or alternative to the above solution, in the above device, the first information related to the vehicle state is the weight of the electric vehicle; and the second information related to the driving scene is the slope.

[0011] As a supplement or alternative to the above solution, in the above device, the gear shifting period includes a torque reduction stage, a gear disengagement stage, a motor speed regulation stage, a gear engagement stage and a torque recovery stage.

[0012] As a supplement or replacement for the above solution, the above device may further include: a sending device for requesting the control of the motor using the target rotation speed.

[0013] As a supplement or alternative to the above solution, in the above device, the receiving device is configured to obtain the rotation speed of the ring gear through an input shaft rotation speed sensor, and to obtain the rotation speed of the sleeve through an output shaft rotation speed sensor.

[0014] According to another aspect of the present application, a computer storage medium is provided, wherein the medium includes instructions, and the instructions execute the above method when running.

[0015] According to another aspect of the present application, a computer program product is provided, comprising a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0016] According to another aspect of the present application, a multi-speed transmission controller for an electric vehicle is provided, wherein the multi-speed transmission controller includes the shift control device as described above.

[0017] The inventor of the present application realizes that the reason why the prior art fails to engage in gear and has a large impact on gear shifting under certain working conditions is that the speed difference between the shaft sleeve and the meshing gear ring (after the motor actively adjusts the speed and before engaging the gear) is rapidly amplified. Generally speaking, since multi-speed transmissions do not have a clutch and a synchronizer ring, they often use a control motor to actively adjust the speed until the difference between the shaft sleeve speed and the meshing gear ring speed is less than 50rpm, and then control the shaft sleeve and the meshing gear ring to perform mechanical hard meshing to synchronize the speeds. When the vehicle is fully loaded and operating on a steep slope, due to the idle travel between the neutral position and the gear meshing position, the shaft sleeve speed will drop rapidly before meshing, causing the speed difference to be amplified (for example, greater than 50rpm) when the shaft sleeve and the gear ring mesh.

[0018] The shift control scheme of the electric vehicle transmission of the embodiment of the present application determines the change in the speed difference between the ring gear and the sleeve according to the received first information related to the vehicle state and the second information related to the driving scene during the shift, and determines the target speed of the motor based on the change in the speed difference and the speed difference base value. In other words, the shift control scheme predicts the change in the speed difference, superimposes the change in advance into the control of the motor speed, and forms a predictive advance amount. With the existence of this advance amount, it can be ensured that the speed difference when the sleeve and the meshing gear ring gear are combined is accurately controlled at the target expected value, making the transmission shifting moment smoother, greatly improving the success rate of shifting, and reducing impact to enhance the driving experience. In addition, the shift control scheme can also reduce the wear on the transmission gears and increase the life and reliability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects and advantages of the present application will become more fully apparent from the following detailed description in conjunction with the accompanying drawings, wherein the same or similar elements are represented by the same reference numerals.

[0020] Figure 1 A schematic flow chart of a shift control method for an electric vehicle transmission according to an embodiment of the present application is shown;

[0021] Figure 2 A schematic structural diagram of a gear shift control device for an electric vehicle gearbox according to an embodiment of the present application is shown;

[0022] Figure 3 shows multiple stages of shift control according to one embodiment of the present application; and

[0023] Figure 4 A logical diagram of a shift control according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0024] Hereinafter, a shift control scheme of an electric vehicle transmission according to various exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0025] Figure 1 FIG. 1 is a flow chart of a shift control method 1000 for an electric vehicle transmission according to an embodiment of the present application. Figure 1 As shown, the shift control method 1000 includes:

[0026] In step S110, first information related to the vehicle state and second information related to the driving scene are received;

[0027] In step S120, during a gear shift, a change in the speed difference between a ring gear and a sleeve in the gearbox is determined according to the first information and the second information; and

[0028] In step S130, a target speed of a control motor is determined based on the speed difference variation and a basic value of the speed difference between the ring gear and the sleeve, wherein the control motor is used to control the gearbox.

[0029] In the context of this application, "electric vehicle" refers to any transportation vehicle that is powered by electric energy and driven by a traction motor, including pure electric vehicles, hybrid vehicles, etc.

[0030] In step S110, first information related to the vehicle state and second information related to the driving scene are received. Here, the first information is related to the vehicle state, and the second information is different from the first information and is related to the driving scene. In the context of the present application, the first information and the second information can be used to determine the change in the speed difference between the ring gear and the bushing in the gearbox. In one embodiment, the "first information related to the vehicle state" may be the weight of the electric vehicle, and the "second information related to the driving scene" may be the slope. Those skilled in the art will appreciate that the first information, in addition to the vehicle weight, may also be other information related to the vehicle state, including but not limited to the acceleration, traction, airbag pressure on the axle, etc. of the vehicle. Similarly, in addition to the slope, the second information may also be other information related to the driving scene, such as map information.

[0031] In step S120, during the gear shifting period, the speed difference change between the ring gear and the sleeve in the gearbox is determined according to the first information and the second information. Here, the "gear shifting period" of the electric vehicle may include multiple stages. Figure 3As shown, the gear shift period 3000 includes in sequence: a torque reduction stage 310, a gear disengagement stage 320, a motor speed regulation stage 330, a gear engagement stage 340, and a torque recovery stage 350. Among them, the torque reduction stage 310, as the name implies, refers to the stage of reducing torque under the control of the TCU after the vehicle is triggered and enters the gear shift process. After completing the torque reduction stage 310, the gear disengagement stage 320 is entered, so that the vehicle enters neutral gear. The motor speed regulation stage 330 is also called the speed synchronization stage, and the speed compensation is also considered in the request value of the motor in this stage (that is, the target speed of the motor is determined based on the speed difference change and the speed difference base value). After the speed synchronization, the gear engagement stage 340 is entered to complete the gear engagement. Finally, in the torque recovery stage 350, the TCU controls the motor to recover the torque, so that the transmission can smoothly and reliably complete the gear shift.

[0032] In electric vehicle transmissions, the term "sleeve" is also called a coupling sleeve, a meshing sleeve or a synchronizer sleeve, which is used for the speed synchronization phase during gear shifting (i.e. Figure 3 The motor speed regulation stage 330 in the shaft sleeve is mechanically hard-engaged with the meshing ring gear. In the neutral range, the rotational speed of the shaft sleeve is related to the wheel speed (for example, connected through the first fixed gear pair). The term "ring gear" is also referred to as the meshing ring gear, and its rotational speed is related to the rotational speed of the motor (for example, connected through the second fixed gear pair). In one embodiment, the rotational speed of the shaft sleeve can be obtained by the output shaft speed sensor, and the rotational speed of the ring gear can be obtained by the input shaft speed sensor. After the shaft sleeve speed is obtained, a speed difference (for example, a speed less than 50rpm) is superimposed on it, and then multiplied by the speed ratio of the second fixed gear pair to obtain the motor target speed and request the motor controller to achieve a speed difference of less than 50rpm.

[0033] However, as described in the background technology section, there is an idle stroke between the neutral position and the gear meshing position. Before the meshing, the speed of the shaft sleeve will drop rapidly, thereby amplifying the speed difference (i.e., there is a "speed difference change"). For example, in neutral, there is no power output at the motor end. When the vehicle is on an uphill slope, the vehicle speed will drop, and thus the speed of the shaft sleeve will also drop (the speed of the shaft sleeve is positively correlated with the wheel speed).

[0034] In order to obtain a balanced shift time, shift shock and shift success rate, an optimal speed difference, i.e., a speed difference base value, can generally be obtained by bench testing or the like. As described in step S130, the target speed of the control motor is determined based on both the speed difference change and the speed difference base value, wherein the control motor is used to control the gearbox. In other words, in order to overcome the speed difference change caused by the change in the shaft sleeve speed during the idle stroke, in the above embodiment, the speed difference change is predicted based on the first information (e.g., vehicle weight) and the second information (e.g., slope).

[0035] although Figure 1Not shown in the figure, in one embodiment, the method 1000 may further include: controlling the motor using the target speed request. That is, by predicting the speed difference change, a predictive advance amount is added to the motor speed control. In this way, by considering the influence of vehicle weight and slope on the speed control target value, gear speed synchronization can be better achieved.

[0036] For example, when the slope is 10% and the vehicle weight is 10 tons, the speed difference change is determined to be 10rpm through calibration, and the speed difference base value is 15rpm. In other words, the speed difference controlled at this time is 25rpm. When the 10-ton vehicle climbs a 10% slope and triggers a gear shift, the shaft sleeve speed will drop by 10rpm when overcoming the idle stroke. Since the target speed of the control motor has taken into account the speed difference change in advance, the speed difference will still be 15rpm when the ring gear and the shaft sleeve are finally combined.

[0037] For another example, when the slope is 20% and the vehicle weight is 10 tons, the speed difference change is determined to be 20 rpm by calibration. For another example, when the slope is 20% and the vehicle weight is 18 tons, the speed difference change is determined to be 25 rpm by calibration.

[0038] It is understandable that the relationship between the speed difference change and the slope and vehicle weight can be determined in advance by calibration. Specifically, the trend of variable changes can be found through hub bench tests / vehicle tests, the trend can be specifically quantified as actual physical values ​​through test data of different environmental parameters, the compensation effect can be tested through software compensation physical value tests, and the relationship between the speed difference change and the slope and vehicle weight can be determined by solidifying the physical values. In addition, the speed difference change can be predicted based on the slope and vehicle weight by looking up a table or estimating using the vehicle dynamics formula. In one embodiment, the speed drop / increase calculation value can be obtained through the vehicle dynamics formula and used as the theoretical control value for the hub / vehicle test.

[0039] In one or more implementations, the speed difference variation is added to the control of the motor speed in advance to form a predictive advance amount. With the existence of this advance amount, the speed difference when the shaft sleeve and the gear ring are combined can be accurately controlled at the target expected value, making the transmission shifting smoother, greatly improving the success rate of ramp shifting, reducing impact, improving driving experience, reducing wear on transmission gears, and increasing the life and reliability of the power system.

[0040] In addition, it is easy for a person skilled in the art to understand that the shift control method 1000 for an electric vehicle transmission provided in the above one or more embodiments of the present application can be implemented by a computer program. For example, the computer program is included in a computer program product, and when the computer program is executed by a processor, the shift control method 1000 for an electric vehicle transmission of one or more embodiments of the present application is implemented. For another example, when a computer storage medium (such as a USB flash drive) storing the computer program is connected to a computer, the shift control method 1000 for an electric vehicle transmission of one or more embodiments of the present application can be executed by running the computer program.

[0041] refer to Figure 2 , Figure 2 FIG. 2 shows a schematic structural diagram of a shift control device 2000 for an electric vehicle transmission according to an embodiment of the present application. Figure 2 As shown, the device 2000 includes: a receiving device 210, a first determining device 220 and a second determining device 230. The receiving device 210 is used to receive first information related to the vehicle state and second information related to the driving scene; the first determining device 220 is used to determine the speed difference change between the gear ring and the shaft sleeve in the gearbox according to the first information and the second information during the gear shift; and the second determining device 230 is used to determine the target speed of the control motor based on the speed difference change and the speed difference base value between the gear ring and the shaft sleeve, wherein the control motor is used to control the gearbox.

[0042] It should be noted that, in the context of this application, "electric vehicle" refers to any transport vehicle driven by a traction motor using electrical energy as power, including pure electric vehicles, hybrid electric vehicles, etc.

[0043] The receiving device 210 is configured to receive first information related to the vehicle state and second information related to the driving scene. Here, the first information is related to the vehicle state, and the second information is different from the first information and is related to the driving scene. In the context of the present application, the first information and the second information can be used to determine the change in the speed difference between the ring gear and the bushing in the gearbox. In one embodiment, the "first information related to the vehicle state" may be the weight of the electric vehicle, and the "second information related to the driving scene" may be the slope. Those skilled in the art will appreciate that the first information, in addition to the vehicle weight, may also be other information related to the vehicle state, including but not limited to, the acceleration, traction, airbag pressure on the axle, etc. of the vehicle. Similarly, in addition to the slope, the second information may also be other information related to the driving scene, such as map information.

[0044] The first determining device 220 is configured to determine the change in the speed difference between the ring gear and the sleeve in the gearbox according to the first information and the second information during the gear shift. Here, the "gear shift period" of the electric vehicle may include multiple stages. Figure 3 As shown, the gear shift period 3000 includes in sequence: a torque reduction stage 310, a gear disengagement stage 320, a motor speed regulation stage 330, a gear engagement stage 340, and a torque recovery stage 350. Among them, the torque reduction stage 310, as the name implies, refers to the stage of reducing torque under the control of the TCU after the vehicle is triggered and enters the gear shift process. After completing the torque reduction stage 310, the gear disengagement stage 320 is entered, so that the vehicle enters neutral gear. The motor speed regulation stage 330 is also called the speed synchronization stage, and the speed compensation is also considered in the request value of the motor in this stage (that is, the target speed of the motor is determined based on the speed difference change and the speed difference base value). After the speed synchronization, the gear engagement stage 340 is entered to complete the gear engagement. Finally, in the torque recovery stage 350, the TCU controls the motor to recover the torque, so that the transmission can smoothly and reliably complete the gear shift.

[0045] In electric vehicle transmissions, the term "sleeve" is also called a coupling sleeve, a meshing sleeve or a synchronizer sleeve, which is used for the speed synchronization phase during gear shifting (i.e. Figure 3 The motor speed control stage 330 in the gearbox is mechanically hard-engaged with the meshing ring gear. In the neutral range, the rotation speed of the sleeve is related to the wheel rotation speed (for example, connected through the first fixed gear pair). The term "ring gear" is also referred to as the meshing ring gear, and its rotation speed is related to the rotation speed of the motor (for example, connected through the second fixed gear pair). In one embodiment, the receiving device 210 is configured to obtain the rotation speed of the ring gear through an input shaft rotation speed sensor, and obtain the rotation speed of the sleeve through an output shaft rotation speed sensor.

[0046] The second determining device 230 is used to determine the target speed of the control motor based on the speed difference variation and the speed difference base value between the ring gear and the sleeve, wherein the control motor is used to control the gearbox. Here, the speed difference base value refers to the optimal speed difference that obtains a balanced shift time, shift shock, and shift success rate through bench testing or the like. In order to overcome the speed difference variation caused by the change in the sleeve speed during the idle stroke, in the above embodiment, the second determining device 230 predicts the speed difference variation based on the first information (e.g., vehicle weight) and the second information (e.g., slope).

[0047] Figure 4 FIG. 2 shows a logic diagram of a shift control according to an embodiment of the present application. Figure 4As shown, the first determining device 410 is configured to determine the speed difference change between the ring gear and the sleeve in the gearbox according to the slope 412 and the vehicle weight 414 during the gear shift. The second determining device 420 determines the final motor speed request value based on the speed difference change provided by the first determining device 410 and the speed difference basic value 416.

[0048] although Figure 2 Not shown in the figure, in one embodiment, the device 2000 may further include: a sending device for controlling the motor using the target speed request. That is, the sending device sends the predicted speed difference change to the control motor so as to add a predictive advance amount to the motor speed control. In this way, by considering the influence of vehicle weight and slope on the speed control target value, gear speed synchronization can be better achieved.

[0049] The above-mentioned device 2000 can be integrated into various types of transmission controllers, including but not limited to, electric vehicle multi-speed transmission controller TCU, hybrid powertrain transmission controller TCU, etc.

[0050] In summary, the shift control scheme of the electric vehicle transmission of the embodiment of the present application determines the change in the speed difference between the ring gear and the sleeve according to the received first information related to the vehicle state and the second information related to the driving scene during the shift, and determines the target speed of the control motor based on the change in the speed difference and the speed difference base value. In other words, the shift control scheme predicts the change in the speed difference, superimposes the change in advance into the control of the motor speed, and forms a predictive advance amount. With the existence of this advance amount, it can be ensured that the speed difference when the sleeve and the meshing gear ring gear are combined is accurately controlled at the target expected value, making the transmission shifting moment smoother, greatly improving the success rate of shifting, and reducing impact to enhance the driving experience. In addition, the shift control scheme can also reduce the wear on the transmission gears and increase the life and reliability of the power system.

[0051] The above examples mainly illustrate the data mining scheme of the embodiments of the present application. Although only some of the embodiments of the present application are described, it should be understood by those skilled in the art that the present application can be implemented in many other forms without departing from its subject matter and scope. Therefore, the examples and embodiments shown are considered to be illustrative rather than restrictive, and the present application may cover various modifications and substitutions without departing from the spirit and scope of the present application as defined in the claims.

Claims

1. A shift control method for an electric vehicle gearbox, characterized in that: The method comprises: Receiving first information related to a vehicle state and second information related to a driving scenario; During a gear shift, determining a change in a speed difference between a ring gear and a sleeve in the gearbox according to the first information and the second information; and A target speed of a control motor is determined based on the speed difference variation and a basic value of the speed difference between the ring gear and the sleeve, wherein the control motor is used to control the gearbox.

2. The method of claim 1, wherein: The first information related to the vehicle state is the weight of the electric vehicle; and the second information related to the driving scene is the slope.

3. The method of claim 1, wherein: The gear shifting period includes a torque reduction phase, a gear disengagement phase, a motor speed regulation phase, a gear engagement phase and a torque recovery phase.

4. The method of claim 1, further comprising: The electric motor is controlled using the target speed request.

5. The method of claim 1, wherein: The rotation speed of the ring gear is acquired through an input shaft rotation speed sensor, and the rotation speed of the sleeve is acquired through an output shaft rotation speed sensor.

6. A gear shift control device for an electric vehicle gearbox, characterized in that: The device comprises: A receiving device, used to receive first information related to the vehicle state and second information related to the driving scene; a first determining device, for determining, during a gear shift, a change in a speed difference between a ring gear and a sleeve in the gearbox according to the first information and the second information; and The second determining device is used to determine the target speed of the control motor based on the speed difference change and the speed difference basic value between the ring gear and the sleeve, wherein the control motor is used to control the gearbox.

7. The device of claim 6, wherein: The first information related to the vehicle state is the weight of the electric vehicle; and the second information related to the driving scene is the slope.

8. The device of claim 6, wherein: The gear shifting period includes a torque reduction phase, a gear disengagement phase, a motor speed regulation phase, a gear engagement phase and a torque recovery phase.

9. The apparatus of claim 6, further comprising: The sending device is used to request the control of the motor using the target speed.

10. The device of claim 6, wherein: The receiving device is configured to obtain the rotation speed of the ring gear through an input shaft rotation speed sensor, and to obtain the rotation speed of the sleeve through an output shaft rotation speed sensor.

11. A computer storage medium, characterized in that: The medium includes instructions which, when executed, perform the method of any one of claims 1 to 5.

12. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

13. A multi-speed gearbox controller for an electric vehicle, characterized in that: The multi-speed gearbox controller comprises a gear shift control device as claimed in any one of claims 6 to 10.

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