Flywheel locking control method and system of single planet row type hybrid gearbox

Abstract

The invention discloses a flywheel locking control method and system for a single planet row type hybrid gearbox, and the method comprises the steps: arbitrating a received flywheel swing request, and activating the flywheel locking control after the arbitration is passed; after entering a flywheel locking control process, adding the target generator swing torque and the engine friction correction torque to obtain an original target generator torque value; according to the original target generator torque value and the negative value of the original target generator torque value, flywheel swing is carried out once; in the swinging process, the maximum value of the original target generator torque value is limited, and the maximum value of the original target generator torque value and the maximum value of the slope of a curve fitted by the negative value of the original target generator and time are limited; setting abnormal swing stopping protection; and judging that two times of swinging of the flywheel are completed, and realizing complete locking of the flywheel. According to the invention, the locking of the engine flywheel can be accurately controlled in an ECVT dual-motor pure electric driving 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, 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 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-axles through the left and right sides of the S1 synchronizer with two sets of gear systems with different speed ratios, and the drive motor is also connected to the wheels through the differential and half-axles 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 lever method dynamic kinematics diagram as shown in 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, the dual-motor pure electric drive mode in which the generator and the drive motor participate in the vehicle drive at the same time can be realized. The lever method dynamic kinematics diagram of the ECVT dual-motor pure electric drive mode is shown below: 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 Z R / Z S The torque of the engine flywheel acting on the generator is T p1 *(1+Z R / Z S ), the two are in the same direction, that is, the positive torque applied by the generator is in the same direction as the flywheel motion.

[0005] In order to realize the ECVT dual-motor pure electric driving 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 a certain number of grooves are set, and two locking solenoid valves are fixed on the hybrid transmission housing side connected to the engine flywheel housing. The VECU sends an unlocking command to the locking controller, and the locking controller controls the on and off of the solenoid valve coil and the return spring to extend and retract the solenoid valve push rod to achieve the locking and unlocking of the flywheel. At the same time, the locking controller feeds back the unlocking state of the solenoid valve to the VECU.

[0006] The locked state of the flywheel is as follows: Figure 5 As shown in the figure, there are three situations: the two solenoid valve push rods are inserted into the flywheel groove, and both sides of the flywheel are locked, such as Figure 5 (a); one side of the push rod extends into the flywheel groove, and the other side push rod pushes against the flywheel protrusion, and the flywheel is locked from rotating in one direction. Figure 5 (b) and 5(c). To ensure that both sides of the flywheel are completely locked each time, it is necessary not only to issue a locking command to drive the solenoid valve push rod to extend, but also to control the generator to output a certain torque to act on the flywheel to make it swing left and right, so that the solenoid valve push rods on both sides are fully extended into the flywheel groove. Therefore, a flywheel locking control method and system for a single planetary gearbox 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, so as to ensure 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 gearbox hybrid transmission, wherein the steps of the method 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 slope of the curve; setting the swing abnormal termination protection, and terminating the flywheel swing in the case of abnormal swing; judging that both flywheel swings are completed, and realizing the complete locking of the flywheel.

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

[0010] Further, during the flywheel lockup control process, when the flywheel swing request is reset or the transmission is not in the ECVT gear position, the final flywheel swing 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, wherein 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 obtaining the corresponding friction correction coefficient by looking up the table.

[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 frictional resistance and rotate.

[0014] Furthermore, the flywheel swing stop speed threshold is specifically: a speed value is preset to satisfy the condition that during the flywheel swing, 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 original target generator torque negative value 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 the flywheel swing.

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

[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 a swing abnormal termination protection to achieve precise control of the flywheel locking under various circumstances.

[0019] Furthermore, swing abnormal suspension protection and swing request arbitration are set to avoid flywheel swing under wrong conditions, which may cause mechanical damage and other hazards;

[0020] Furthermore, limiting the maximum torque when the flywheel swings can prevent the push rod from colliding with the flywheel due to excessive torque when the flywheel swings, causing NVH and other possible mechanical damage problems;

[0021] Furthermore, limiting the slope of the curve obtained by fitting the image of the torque when the flywheel swings can avoid the NVH problem caused by the collision between the push rod and the flywheel due to the torque rising too fast during the flywheel swing, and avoid the signal jump collected by the speed sensor due to the rebound of the flywheel after the push rod hits the flywheel, thereby causing the misjudgment of the completion of the flywheel swing;

[0022] Furthermore, when judging whether the next flywheel swing is completed, setting a waiting time can avoid misjudgment of the swing completion caused by the fact that the torque of the next flywheel swing has not reached a certain value and the flywheel has not actually rotated.

[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 briefly introduces 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 creative work.

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

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

[0027] Figure 3 It is a lever method dynamics analysis diagram of the ECVT dual-motor driving mode in the prior art;

[0028] Figure 4It is a 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 It is a schematic diagram of the locked state of the flywheel of the present invention;

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

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

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

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 used to limit the present invention.

[0034] It should be noted that the illustrations provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.

[0035] In the present invention, it is also necessary to explain that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0036] Example 1

[0037] This embodiment provides a flywheel lock control method for a single planetary gearbox hybrid transmission, and the specific steps 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, when the flywheel speed exceeds a certain preset value during the flywheel swing process, 100rpm 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 fully extending 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 an original target generator torque value.

[0043] Specifically, the method for obtaining the target generator swing torque is as follows: 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 just starts to swing, a larger torque is required to overcome friction to make the flywheel rotate. 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] Flywheel speed 0 20 30 40 50 Generator torque 10 8 6 3 0

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

[0047] Specifically, the method for obtaining the engine friction correction torque is: divide the engine friction torque by the speed ratio of the planetary carrier and the sun gear, and then multiply the obtained value by the friction correction coefficient, wherein the method for obtaining the friction correction coefficient is, according to experimental calibration, to obtain the relationship between the absolute value of the flywheel speed and the friction correction coefficient, to establish a one-dimensional table of the absolute value of the flywheel speed-friction correction coefficient, as shown in Table 2, to obtain the actual absolute value of the flywheel speed, and to obtain the corresponding friction correction coefficient 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] Flywheel speed 0 20 30 40 50 Friction correction factor 1 0.8 0.5 0.3 0

[0050] Table 2 One-dimensional table of absolute value of flywheel speed-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, and both sides of the flywheel are locked; a push rod on one side extends into the flywheel groove, and a push rod on the other side presses against the flywheel protrusion, and the flywheel is locked from rotating in one direction. Therefore, when designing the swing torque direction of the flywheel, it is necessary to swing in both directions, either forward first and then reverse, or reverse first and then forward. This embodiment adopts the former, and the preset time of each swing of the flywheel in this embodiment is 500ms.

[0054] Specifically, in order to avoid excessive torque when the flywheel swings, which may cause the push rod to collide with the flywheel, causing NVH and possible mechanical damage, the maximum torque of the flywheel swing should be limited. The limit is made in two aspects: the maximum torque limit of a single swing of the flywheel is calibrated according to the actual situation and cannot be lower than the maximum torque value that can drag the flywheel to overcome the low-temperature friction resistance to rotate; the flywheel swing speed over-limit protection, the speed of the flywheel when swinging should not be greater than the above-mentioned flywheel speed stop speed 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 to be less than a preset slope value at any time. In this embodiment, the slope 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, causing the signal collected by the speed sensor to jump, thereby causing a misjudgment that the flywheel swing is completed.

[0056] S4. Set the swing abnormal termination protection to terminate the flywheel swing in the event of abnormal swing.

[0057] Specifically, the 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 stopped; 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 has not been completed within a 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, the flywheel swing starts with a positive judgment. When the preset time of the first flywheel swing is reached and the absolute value of the flywheel speed is lower than the preset speed value, in this embodiment, the preset speed value is 10rpm, and it is considered that the first flywheel swing is completed; then another flywheel swing in the opposite direction is judged, and the target generator torque changes from positive to negative. When it is judged that the actual generator torque is lower than 0 and after waiting for a period of time, the flywheel speed is also lower than 0, it is considered that the reverse flywheel swing is completed, wherein the calibration of the waiting time should take into account the actual flywheel reverse rotation and the actual negative generator torque size, to ensure that the flywheel swing can be completed within this time, to avoid the flywheel swing torque size not reaching a certain value, that is, the flywheel has not actually rotated before it is judged to be completed, resulting in a misjudgment of the completion of the flywheel swing. When both flywheel swings are judged to be completed, the flywheel swing is completed.

[0060] Example 2

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

[0062] The present invention provides a flywheel locking control method and system for a single planetary gearbox hybrid transmission. The transmission performs arbitration after receiving a flywheel swing request. After the arbitration is passed, the swing torque of the target generator is calculated, and two flywheel swings in opposite directions are performed. At the same time, swing abnormal termination protection is set, and swing completion judgment is performed after the swing to ensure that each flywheel lock is successful, thereby enabling the transmission to enter the ECVT dual-motor pure electric drive mode. The present invention better considers the NVH problem in the locking process and effectively avoids mechanical damage in the flywheel locking process. At the same time, swing abnormal termination protection is set during the flywheel swing to prevent the flywheel from swinging under wrong conditions, thereby ensuring the smooth progress of the locking 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, and 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 order of execution of each step in the above embodiment 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 embodiment 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 these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A flywheel lock control method for a single planetary gearbox hybrid transmission, characterized in that: include: Arbitrate the received flywheel swing request, activate the flywheel locking control after the arbitration is passed, otherwise, do not activate the flywheel locking control and latch the final flywheel swing request; After entering the flywheel locking 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 swinging 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 and time are fitted respectively to limit the maximum value of the slope of the curve; Set up abnormal swing stop protection to stop the flywheel swing in the event of abnormal swing; It is determined that both flywheel swings are completed, thus achieving full locking of the flywheel.

2. The flywheel lock 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 gearbox is currently in the ECVT gear position, and the ECVT gear position specifically means that one synchronizer of the gearbox is in the middle position and the other synchronizer is in the left or right position.

3. The flywheel lock 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 lock 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: 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.

5. The flywheel lock 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, wherein the method for obtaining the friction correction coefficient is, according to 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 obtaining the corresponding friction correction coefficient 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 frictional resistance and rotate.

7. The flywheel lock 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 condition that during the flywheel swing, 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 lock 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 swinging process of the flywheel, 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 lock control method of a single planetary gearbox hybrid transmission according to claim 1, characterized in that: The judgment basis for the flywheel to complete one swing according to the original target generator torque value is that 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 locking control method of the single planetary gearbox hybrid transmission as described in any one of claims 1-9.

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