A flywheel lockup control method and system for a single planetary gearbox

Abstract

The present invention discloses a flywheel lockup control method and system for a single planetary gearbox hybrid transmission, wherein the method includes the following steps: arbitrating a received flywheel swing request and activating the flywheel lockup control after the arbitration is passed; after entering the flywheel lockup control process, summing the target generator swing torque and the engine friction correction torque to obtain an original target generator torque value; performing a flywheel swing according to the original target generator torque value and its negative value respectively; during the swinging process, limiting the maximum value of the original target generator torque value and limiting the maximum value of the slope of the curve of the original target generator torque value and its negative value fitted with time; setting a swing abnormality termination protection; and determining that both flywheel swings are completed to achieve complete lockup of the flywheel. The present invention can accurately control the locking of the engine flywheel in the ECVT dual-motor pure electric drive mode.

Description

Technical Field

[0001] The present invention relates to the field of vehicle power devices, and in particular to a flywheel locking control method and system for a single planetary gearbox hybrid transmission. Background Art

[0002] A structure of a planetary power split multi-speed hybrid transmission Figure 1 As shown, the engine flywheel is connected to the planetary carrier of the single planetary gear set, the generator is connected to the sun gear and engaged on the left and right sides of the S2 synchronizer, so that the entire planetary gear set is connected as one and the sun gear and the generator are relatively stationary. The ring gear is connected to the wheels through the differential and half-shafts from the left and right sides of the S1 synchronizer with two sets of gear systems with different speed ratios. The drive motor is also connected to the wheels through the differential and half-shafts with another set of gear systems.

[0003] When the S2 synchronizer is in the middle position and the S1 synchronizer is to the left or right, the gearbox is in ECVT. Based on the dynamic kinematics principle of a single planetary gear, part of the engine's output power is transmitted to the wheels through the planetary carrier, the ring gear, the S1 synchronizer, and the gear train, and the other part is transmitted to the generator through the sun gear for power generation, thus realizing the ECVT power split mode. This mode is based on the dynamic kinematics diagram of the lever method as shown in the figure. Figure 2 shown.

[0004] In addition to the power split mode, in the ECVT gear, when the engine is stopped, if the generator outputs positive torque, the engine will be dragged by the generator. At this time, the engine is fixed. Based on the planetary gear lever principle, if the generator outputs positive torque, after speed ratio conversion, it will be output through the wheel end as negative torque at the ring gear end. If the generator outputs negative torque, after the same speed ratio conversion, it will be output to the wheel end as positive torque at the ring gear end. Combined with the torque output of the drive motor, a dual-motor pure electric drive mode can be realized in which the generator and the drive motor participate in the vehicle drive at the same time. The lever method dynamic kinematics diagram under the ECVT dual-motor pure electric drive mode is shown as follows: Figure 3 As shown, combined with the principle of force balance, the torque ratio acting on the sun gear and the ring gear is the lever ratio , the torque on the engine flywheel acted on by the generator is , the two are in the same direction, that is, the positive torque applied by the generator is in the same direction as the flywheel movement.

[0005] In order to realize the ECVT dual-motor pure electric drive mode, the engine flywheel must be locked. The locking mechanism is as follows: Figure 4As shown, the flywheel is spaced at a fixed angle and provided with a certain number of grooves. Two locking solenoid valves are fixed to the hybrid transmission housing, which is connected to the engine flywheel housing. The VECU issues an unlock command to the lock controller. The lock controller controls the solenoid valve coil and the return spring to extend and retract the solenoid valve push rod to lock and unlock the flywheel. At the same time, the lock controller reports the solenoid valve unlock status to the VECU.

[0006] The locked state of the flywheel is as follows Figure 5 As shown, there are three situations: both solenoid valve push rods extend into the flywheel groove, and both sides of the flywheel are locked, such as Figure 5 As shown in (a), one side of the push rod extends into the flywheel groove, and the other side push rod presses against the flywheel protrusion, and the flywheel is locked from rotating in one direction. Figure 5 (b) and 5(c). To ensure complete locking of both sides of the flywheel, not only must a locking command be issued to extend the solenoid valve push rod, but the generator must also be controlled to output a certain torque to the flywheel, causing it to swing left and right, thereby fully extending the solenoid valve push rods on both sides into the flywheel grooves. Therefore, a flywheel locking control method and system for a single planetary gear hybrid transmission is urgently needed. Summary of the Invention

[0007] The main purpose of the present invention is to provide a flywheel locking control method and system for a single planetary gearbox hybrid transmission, ensuring the successful locking of the engine flywheel under different conditions, thereby enabling the transmission to enter the ECVT dual-motor pure electric drive mode.

[0008] The technical solution adopted by the present invention is: a flywheel lockup control method and system for a single planetary hybrid transmission, wherein the method steps include: arbitrating the received flywheel swing request, activating the flywheel lockup control after the arbitration is passed, otherwise not activating the flywheel lockup control and latching the final flywheel swing request; after entering the flywheel lockup control process, adding the target generator swing torque and the engine friction correction torque to obtain the original target generator torque value; performing a flywheel swing according to the original target generator torque value and its negative value respectively; during the swinging process, limiting the maximum value of the original target generator torque value according to the maximum torque limit of a single swing and the maximum torque limit corresponding to the flywheel swing stop speed threshold, fitting the curves of the original target generator torque value and its negative value with time respectively, and limiting the maximum value of the curve slope; setting the swing abnormal termination protection to terminate the flywheel swing in the event of an abnormal swing; judging that both flywheel swings are completed to achieve complete locking of the flywheel.

[0009] Furthermore, the condition for the flywheel swing request arbitration is that the transmission is currently in an ECVT gear position, and the ECVT gear position specifically means that one synchronizer of the transmission is in a middle position and the other synchronizer is in a left or right position.

[0010] Furthermore, during the flywheel lockup control process, when the flywheel oscillation request is reset or the transmission is not in the ECVT gear position, the final flywheel oscillation request is reset.

[0011] Furthermore, the method for obtaining the target generator swing torque is: according to experimental calibration, the relationship between the absolute value of the flywheel speed and the target generator swing torque is obtained, a one-dimensional table of the absolute value of the flywheel speed-target generator swing torque is established, the actual absolute value of the flywheel speed is obtained, and then the corresponding target generator swing torque is obtained by looking up the table.

[0012] Furthermore, the method for obtaining the engine friction correction torque is: dividing the engine friction torque by the speed ratio of the planetary carrier and the sun gear, and then multiplying the obtained value by the friction correction coefficient. The method for obtaining the friction correction coefficient is, based on experimental calibration, obtaining the relationship between the absolute value of the flywheel speed and the friction correction coefficient, establishing a one-dimensional table of the absolute value of the flywheel speed-friction correction coefficient, obtaining the actual absolute value of the flywheel speed, and looking up the table to obtain the corresponding friction correction coefficient.

[0013] Furthermore, the maximum torque limit of the single swing is calibrated according to actual conditions and is not less than the maximum torque value that enables the flywheel to overcome friction resistance and rotate.

[0014] Furthermore, the flywheel swing stop speed threshold is specifically: a speed value is preset to meet the requirement that during the flywheel swing process, when the flywheel speed exceeds the preset speed value, the flywheel is judged to be in an abnormal swing condition and the flywheel swing request is reset, wherein the abnormal swing condition also includes: the gearbox is not in the ECVT gear position and the single swing time of the flywheel exceeds the preset time.

[0015] Furthermore, a slope value is preset to satisfy the requirement that during the flywheel swing process, the absolute value of the slope of the curve fitted by the original target generator torque value and the negative target generator torque value and time is less than the preset slope value at any time.

[0016] Furthermore, the judgment basis for the flywheel to complete one swing according to the original target generator torque value is that the swing time reaches the preset time and the absolute value of the flywheel speed is lower than the preset value; the judgment basis for the flywheel to complete another swing according to the negative value of the original target generator torque is that the actual generator torque is less than 0, and after waiting for the preset time, the flywheel speed is also less than 0, wherein the preset waiting time is sufficient to complete this flywheel swing.

[0017] Another aspect of the present invention provides a single planetary gearbox hybrid transmission system, which is adapted to the above-mentioned flywheel lockup control method of the single planetary gearbox hybrid transmission.

[0018] The beneficial effects of the present invention are as follows: the present invention performs arbitration after receiving a flywheel swing request in the ECVT gear position, calculates the target generator torque value after the arbitration is passed and limits it, the engine drags the flywheel to swing twice in opposite directions, and makes a swing completion judgment, and at the same time sets the swing abnormal termination protection to achieve precise control of the flywheel locking under various circumstances.

[0019] Furthermore, swing abort protection and swing request arbitration are set to avoid flywheel swing under incorrect conditions, which may cause mechanical damage and other hazards.

[0020] Furthermore, limiting the maximum torque during flywheel swing can prevent excessive flywheel swing torque from causing the push rod to collide with the flywheel, causing NVH and other possible mechanical damage issues.

[0021] Furthermore, limiting the slope of the curve obtained by fitting the torque image during flywheel swing can avoid NVH problems caused by the push rod colliding with the flywheel due to the torque rising too quickly during flywheel swing, and avoid the flywheel rebounding after the push rod collides with the flywheel, which causes the signal collected by the speed sensor to jump, thereby misjudging the completion of flywheel swing.

[0022] Furthermore, when performing the next flywheel swing completion judgment, setting a waiting time can avoid the swing completion misjudgment caused by the next flywheel swing torque not reaching a certain value and the flywheel not actually rotating.

[0023] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a structural diagram of a planetary power split multi-speed hybrid transmission in the prior art;

[0026] Figure 2 This is a dynamic analysis diagram of the ECVT power split mode lever method in the prior art;

[0027] Figure 3 This is a lever method dynamic analysis diagram of the ECVT dual-motor drive mode in the prior art;

[0028] Figure 4A schematic diagram of the flywheel and locking mechanism of the planetary gearbox power split multi-speed hybrid transmission of the present invention;

[0029] Figure 5 This is a schematic diagram of the flywheel locked state of the present invention;

[0030] Figure 6 This is a logic block diagram of the flywheel swing control strategy of the present invention;

[0031] Figure 7 This is a schematic diagram of a flywheel swing of the present invention;

[0032] Figure 8 Schematic diagram of another flywheel swing of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] It should be noted that the illustrations provided in the embodiments of the present invention are only schematic illustrations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0035] In the present invention, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like are used to indicate positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present application and to simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present application. Furthermore, the terms "first" and "second" are used solely for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0036] Example 1

[0037] This embodiment provides a flywheel lockup control method for a single planetary gearbox hybrid transmission, the specific steps of which include:

[0038] S1. After receiving the flywheel swing request, the generator performs flywheel swing request arbitration.

[0039] Specifically, the flywheel swing request arbitration is to confirm that the transmission is currently in the ECVT gear position, otherwise the flywheel cannot be dragged to rotate by controlling the generator torque, and the final flywheel swing request trigger is latched.

[0040] Furthermore, if the flywheel speed exceeds a certain preset value during the flywheel swing process, which is 100 rpm in this embodiment, the flywheel swing request will also be reset. This preset speed value is called the flywheel swing stop speed threshold. At this time, the flywheel is not locked due to the solenoid valve push rod not being fully extended into the flywheel groove or other mechanical damage, so there is no need to swing the flywheel at this time.

[0041] Furthermore, when the flywheel swing request is reset or the actual gear is no longer ECVT, the final flywheel swing request is reset.

[0042] S2. Add the target generator swing torque and the engine friction correction torque to calculate the original target generator torque value.

[0043] Specifically, the target generator swing torque is obtained by: according to experimental calibration, the relationship between the absolute value of the flywheel speed and the target generator swing torque is obtained, and a one-dimensional table of the absolute value of the flywheel speed-target generator swing torque is established, as shown in Table 1. The actual absolute value of the flywheel speed is obtained, and then the corresponding target generator swing torque is obtained by looking up the table.

[0044] Furthermore, the absolute value of the flywheel speed is negatively correlated with the target generator swing torque value. This is because when the flywheel first starts to swing, a larger torque is required to overcome friction and rotate the flywheel. As the flywheel swing speed increases, the swing torque should be gradually reduced to reduce the impact between the push rod and the flywheel groove.

[0045]

[0046] Table 1 One-dimensional table of flywheel speed absolute value-target generator swing torque

[0047] Specifically, the engine friction correction torque is obtained by dividing the engine friction torque by the speed ratio of the planetary carrier to the sun gear, and then multiplying the obtained value by the friction correction coefficient. The friction correction coefficient is obtained by obtaining the relationship between the absolute value of the flywheel speed and the friction correction coefficient based on experimental calibration, and establishing a one-dimensional table of the absolute value of the flywheel speed-friction correction coefficient, as shown in Table 2. The actual absolute value of the flywheel speed is obtained, and the corresponding friction correction coefficient is obtained by looking up the table.

[0048] Furthermore, the engine friction correction torque is used to overcome the friction resistance of the rotating parts inside the flywheel engine and is negatively correlated with the water temperature. Considering that the friction torque value has a certain error and is corrected based on the flywheel speed, the friction correction coefficient is also negatively correlated with the absolute value of the flywheel speed.

[0049]

[0050] Table 2 One-dimensional table of flywheel speed absolute value-friction correction coefficient

[0051] S3. Perform a first flywheel swing based on the obtained original target generator torque value, perform another flywheel swing in the opposite direction based on the negative target generator torque value, limit the maximum value of the original target generator torque value during the swing, and limit the maximum value of the original target generator torque slope during the swing.

[0052] Specifically, the negative target generator torque value is obtained by multiplying the original target generator torque value by -1.

[0053] Specifically, when the flywheel is locked, the following situations may occur: both push rods extend into the flywheel groove, locking both sides of the flywheel; or one push rod extends into the flywheel groove, while the other push rod hits the flywheel protrusion, locking the flywheel from rotating in one direction. Therefore, when designing the flywheel's swing torque direction, it is necessary to swing in both directions: first forward and then reverse, or first reverse and then forward. This embodiment adopts the former. In this embodiment, the preset time for each flywheel swing is 500ms.

[0054] Specifically, to prevent excessive torque during flywheel swing, which could cause the push rod to collide with the flywheel, leading to NVH and possible mechanical damage, the maximum torque limit for flywheel swing is implemented. This limitation is achieved in two ways: the maximum torque limit for a single flywheel swing is calibrated based on actual conditions and cannot be lower than the maximum torque that can drive the flywheel to rotate by overcoming low-temperature friction resistance; and the flywheel swing speed overlimit protection ensures that the flywheel speed during swinging is no greater than the aforementioned flywheel speed stop threshold.

[0055] Specifically, when the flywheel swings, the slope of the curve fitted by the original target generator torque value and the negative target generator torque value and time is limited so that it is less than a preset slope value at any time. In this embodiment, it is 100 Nm / s, so as to avoid the torque rising too fast during the flywheel swing, resulting in NVH problems caused by the push rod colliding with the side of the flywheel groove, and the flywheel rebounding after the collision and the signal collected by the speed sensor jumping, thereby causing the misjudgment of the completion of the flywheel swing.

[0056] S4. Set the swing abnormality suspension protection to stop the flywheel swing in the event of abnormal swing.

[0057] Specifically, abnormal swing conditions include: when the flywheel speed exceeds the flywheel swing stop speed threshold during the flywheel swing process, the flywheel is not locked due to reasons such as the solenoid valve not being executed or the locking mechanism being mechanically damaged. At this time, there is no need to swing the flywheel anymore, that is, the swing is terminated; the actual gear position of the gearbox is no longer ECVT, and the generator torque cannot be transmitted to the flywheel to drag the flywheel to rotate; the flywheel swing times out, that is, the swing is not completed within the preset time after the swing request is issued, which is 3s in this embodiment.

[0058] S5. Determine that both flywheel swings are completed, and achieve complete locking of the flywheel.

[0059] Specifically, a positive judgment is performed at the beginning of the flywheel swing. When the preset time for the first flywheel swing is reached and the absolute value of the flywheel speed is lower than the preset speed value (in this embodiment, this preset speed value is 10 rpm), the first flywheel swing is considered complete. Then, another flywheel swing in the opposite direction is judged, and the target generator torque changes from positive to negative. When the actual generator torque is judged to be lower than 0 and the flywheel speed is also lower than 0 after a period of waiting, the reverse flywheel swing is considered complete. The calibration of the waiting time takes into account the actual flywheel reverse rotation and the actual negative generator torque to ensure that the flywheel swing can be completed within this time, avoiding the erroneous judgment that the flywheel swing is completed before the flywheel swing torque reaches a certain value, that is, before the flywheel actually rotates. When both flywheel swings are judged to be complete, the flywheel swing is complete.

[0060] Example 2

[0061] This embodiment provides a single planetary gearbox hybrid transmission system, which is adapted to the speed-based flywheel lockup control method of the single planetary gearbox hybrid transmission described in Example 1.

[0062] The present invention provides a flywheel lockup control method and system for a single-planetary hybrid transmission. Upon receiving a flywheel swing request, the transmission performs arbitration. Upon successful arbitration, the target generator's swing torque is calculated, and two flywheel swings are performed in opposite directions. A swing abort protection function is implemented, and a swing completion determination is performed after each swing to ensure successful flywheel lockup, thereby enabling the transmission to enter the ECVT dual-motor pure electric drive mode. This invention effectively addresses NVH issues during the lockup process and effectively avoids mechanical damage during the flywheel lockup process. Furthermore, a swing abort protection function is implemented during flywheel swing to prevent the flywheel from swinging under erroneous conditions, thereby ensuring a smooth lockup sequence.

[0063] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0064] The size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0065] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A flywheel lockup control method for a single planetary gearbox hybrid transmission, characterized in that: include: Arbitrating the received flywheel swing request, activating the flywheel locking control after the arbitration is passed, otherwise not activating the flywheel locking control and latching the final flywheel swing request; After entering the flywheel lockup control process, the target generator swing torque and the engine friction correction torque are added to obtain an original target generator torque value; the flywheel swing is performed once according to the original target generator torque value and its negative value respectively; During the swing process, the maximum value of the original target generator torque value is limited according to the maximum torque limit of a single swing and the maximum torque limit corresponding to the flywheel swing stop speed threshold, and the curves of the original target generator torque value and its negative value versus time are fitted respectively to limit the maximum value of the curve slope; Set up swing abnormality suspension protection to stop the flywheel swing in the event of abnormal swing; It is determined that both flywheel swings are completed, and the flywheel is fully locked.

2. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: The condition for the flywheel swing request arbitration is that the transmission is currently in the ECVT gear position, and the ECVT gear position specifically means that one synchronizer of the transmission is in the middle position and the other synchronizer is in the left or right position.

3. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 2, characterized in that: During the flywheel lockup control process, when the flywheel swing request is reset or the transmission is not in the ECVT gear, the final flywheel swing request is reset.

4. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: The method for obtaining the target generator swing torque is as follows: based on experimental calibration, the relationship between the absolute value of the flywheel speed and the target generator swing torque is obtained, a one-dimensional table of the absolute value of the flywheel speed-target generator swing torque is established, the actual absolute value of the flywheel speed is obtained, and then the corresponding target generator swing torque is obtained by looking up the table.

5. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: The method for obtaining the engine friction correction torque is: dividing the engine friction torque by the speed ratio of the planetary carrier and the sun gear, and then multiplying the obtained value by the friction correction coefficient. The method for obtaining the friction correction coefficient is: according to experimental calibration, the relationship between the absolute value of the flywheel speed and the friction correction coefficient is obtained, and a one-dimensional table of the absolute value of the flywheel speed-friction correction coefficient is established. The actual absolute value of the flywheel speed is obtained, and the corresponding friction correction coefficient is obtained by looking up the table.

6. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: The maximum torque limit of a single swing is calibrated according to actual conditions and is not less than the maximum torque value that enables the flywheel to overcome friction resistance and rotate.

7. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: The flywheel swing stop speed threshold is specifically: a speed value is preset to meet the requirement that during the flywheel swing process, when the flywheel speed exceeds the preset speed value, the flywheel is judged to be in an abnormal swing condition and the flywheel swing request is reset, wherein the abnormal swing condition also includes: the gearbox is not in the ECVT gear position and the single swing time of the flywheel exceeds the preset time.

8. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: A slope value is preset to satisfy the requirement that during the flywheel swing process, the absolute value of the slope of the curve fitted by the original target generator torque value and the negative target generator torque value and time is less than the preset slope value at any time.

9. The flywheel lockup control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: The flywheel completes one swing according to the original target generator torque value based on the following criteria: the swing time reaches a preset time and the absolute value of the flywheel speed is lower than a preset value; The judgment basis for the flywheel to complete another swing according to the original target generator torque negative value is that the actual generator torque is less than 0, and after waiting for a preset time, the flywheel speed is also less than 0, wherein the preset waiting time is sufficient to complete this flywheel swing.

10. A single planetary gearbox hybrid transmission system, characterized in that: The system is adapted to the flywheel lockup control method of a single planetary gearbox hybrid transmission as described in any one of claims 1 to 9.

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