A method for engaging a dog clutch of a hybrid transmission

Abstract

The application provides a method for engaging a cogged clutch of a hybrid transmission, comprising: in an unengaged state, performing a difference adjusting process, including: a motor controller obtaining a rotation speed of a driving motor output to a vehicle wheel, and a rotation speed ratio calculation obtaining a rotation speed r1 of a driving motor end of the clutch; the motor controller controlling a generator to adjust a rotation speed r2 of a generator end of the clutch in a rotation speed loop, so that a difference between the rotation speed r1 and the rotation speed r2 of the clutch is a target difference D (D≠0); performing an engaging action, including: the motor controller controlling the generator to adjust a torque of the generator end of the clutch in a torque loop, so that the difference between the rotation speed r1 and the rotation speed r2 of the clutch is 0; and the clutch action realizing coupling of an engine and the driving motor.

Description

Technical Field

[0001] This invention relates to the field of jaw clutch technology and control technology, and more particularly to a method for controlling the engagement of a jaw clutch in a hybrid transmission. Background Technology

[0002] Using a dog clutch to achieve parallel drive of the engine in hybrid vehicles has a significantly lower system cost than hydraulic clutches, and is the future trend for hybrid transmissions with a P1+P3 architecture.

[0003] Existing hybrid transmissions with jaw clutches require a separate clutch controller (CCU) outside the transmission for clutch engagement. The CCU controls the jaw clutch, necessitating dedicated CAN communication, which is costly. Furthermore, during clutch engagement control, the CCU communicates first with the motor controller (PEU), then with the vehicle controller (HCU), and finally receives a feedback signal from the HCU. This results in a long communication chain with numerous nodes. Summary of the Invention

[0004] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a method for engaging the jaw clutch of a hybrid transmission that is directly controlled by a motor controller without the need for a clutch controller.

[0005] This invention discloses a method for engaging a jaw clutch in a hybrid transmission, comprising the following steps: In the unengaged state, a differential adjustment process is performed, including: the motor controller acquires the rotational speed output by the drive motor to the vehicle wheels, and calculates the engagement speed ratio to obtain the rotational speed r1 at the drive motor end of the clutch; the motor controller controls the generator to adjust the rotational speed r2 at the generator end of the clutch via a speed loop, such that the difference between the rotational speeds r1 and r2 at the clutch ends is a target difference value D (D≠0); engagement is performed, including: the motor controller controls the generator to adjust the torque at the generator end of the clutch via a torque loop, such that the difference between the rotational speeds r1 and r2 at the clutch ends is 0; the clutch actuates to couple the engine and the drive motor; it is determined whether the actual difference n between the rotational speeds r1 and r2 at the clutch ends is less than a preset speed difference threshold and continues for a first preset time; if not, the engagement is performed again; if so, the clutch engagement state is maintained, and clutch engagement is completed.

[0006] Preferably, before engaging the clutch, the method further includes: determining whether the actual difference n between the rotational speeds r1 and r2 at both ends of the clutch is within a preset speed difference range and continues for a second preset time, wherein the target difference D is within the preset speed difference range; if not, the adjustment process continues; if yes, the engagement is performed.

[0007] Preferably, determining whether the actual difference n between the rotational speeds r1 and r2 at both ends of the clutch is less than a preset speed difference threshold and continues for a first preset time; if so, maintaining the clutch engagement state and completing clutch engagement includes: if so, performing a verification process, including: the motor controller allocating the torque T1 output by the drive motor in the disengaged state to the generator and the drive motor, and the torque allocated by the drive motor is greater than the torque allocated by the generator; determining whether the actual difference n between the rotational speeds r1 and r2 at both ends of the clutch is less than the preset speed difference threshold; if so, maintaining the clutch engagement state and completing clutch engagement; if not, all of the torque T1 is allocated to the generator, and the generator speed is controlled by a torque loop, abandoning clutch engagement.

[0008] Preferably, the motor controller distributes the torque T1, which is entirely output by the drive motor in the disengaged state, to the generator and the drive motor by: distributing 10% of the torque T1, which is entirely output by the drive motor in the disengaged state, to the generator and 90% to the drive motor.

[0009] Preferably, the upper limit of the target difference D is set according to the tooth thickness and tooth clearance of the clutch engagement teeth, and the lower limit of the target difference D is set according to the desired clutch engagement time.

[0010] Preferably, the target difference D is 35 rpm.

[0011] Preferably, determining whether the actual difference n between the rotational speeds r1 and r2 at both ends of the clutch is within a preset speed difference range and continues for a second preset time includes: setting a fluctuation value, and taking positive or negative fluctuation values ​​for the target difference D to obtain the preset speed difference range.

[0012] Preferably, the preset speed difference threshold is set according to the tooth thickness and tooth clearance of the clutch engagement teeth; the preset speed difference threshold is less than the preset speed difference range.

[0013] Preferably, determining whether the actual difference n between the rotational speeds r1 and r2 at both ends of the clutch is less than a preset speed difference threshold and lasts for a first preset time; if not, then restarting the engagement action includes: if not, and lasting for less than a third preset time, then restarting the engagement action; if not, and lasting for more than or equal to a third preset time, then abandoning clutch engagement.

[0014] Preferably, the step of abandoning clutch engagement includes: the motor controller feeding back engagement error information to the vehicle controller; the step of completing clutch engagement includes: the motor controller feeding back engagement success information to the vehicle controller; and the step of sending a clutch engagement command to the motor controller before the adjustment process in the non-engaged state further includes: the vehicle controller sending a clutch engagement command to the motor controller.

[0015] Compared with existing technologies, the above technical solution has the following advantages:

[0016] 1. In this invention, communication is directly established between the motor controller PEU and the vehicle controller HCU. Specifically, the motor controller PEU collects data signals and the vehicle controller HCU sends commands, eliminating the need for the clutch controller CCU. This simplifies the communication link and makes the control more reliable. Furthermore, the clutch controller CCU can be omitted, allowing the clutch control logic to be integrated into the motor controller.

[0017] 2. By setting the target difference D to be non-zero, a speed difference can be artificially given to both ends of the clutch. When the tooth tips of the meshing teeth at both ends of the clutch are opposite at the initial engagement, this speed difference can be used to adjust the tooth tips of the meshing teeth at both ends to be staggered, thereby achieving successful meshing of the meshing teeth at both ends.

[0018] 3. When performing the engagement operation, changing the generator speed loop control to torque loop control can avoid the strong impact on the meshing teeth at both ends of the clutch caused by continuous generator speed control at the moment of engagement.

[0019] 4. During the verification process, the torque T1, which was originally entirely output by the drive motor, is distributed between the generator and the drive motor. Whether the engagement action in the previous step is truly completed can be determined by whether there is a significant change in the speed difference of the generator. Furthermore, by ensuring that the torque distributed to the drive motor is greater than that distributed to the generator, even if the engagement action is not truly achieved, the torque distributed to the drive motor is not significantly reduced compared to before the distribution, so there will be no significant change in vehicle speed for the driver, and the verification will not affect the driving experience. Moreover, this verification method does not require the use of sensors or other components. Attached Figure Description

[0020] Figure 1 A simplified architectural diagram of a preferred embodiment of the hybrid transmission provided by the present invention;

[0021] Figure 2 A flowchart of the engagement control method for the jaw clutch of a hybrid transmission provided by the present invention. Detailed Implementation

[0022] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0023] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0024] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0025] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0026] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0028] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0029] This invention relates to a hybrid powertrain system with a P1+P3 hybrid transmission, where P1 is a generator and P3 is a drive motor. A classic P1+P3 hybrid architecture is shown in the appendix. Figure 1 In this transmission system, the engine and generator are normally connected, the drive motor is connected to the engine via a clutch, and the drive motor is connected to the vehicle's wheels to output power to drive them. Not shown in this diagram, the generator is also connected to the drive motor to supply power to it, enabling it to drive the wheels. In the disengaged clutch state (often called series mode), the engine's power is transmitted only to the generator, which then generates electricity and transmits it to the drive motor to drive the wheels. In the engaged clutch state (often called parallel mode), part of the engine's power is transmitted to the generator (which then generates electricity and transmits it to the drive motor), and part of the power is also transmitted to the drive motor via the engaged clutch, ultimately driving the wheels.

[0030] This invention discloses a method for controlling the engagement of a jaw clutch in a hybrid transmission, used to control the change from a series mode to a parallel mode, i.e., the clutch engagement process. It mainly includes four processes: differential adjustment (adjusting the speed difference between the two ends of the clutch to create favorable conditions for engagement), action (controlling the clutch to decelerate while simultaneously applying a large current to the coil to achieve shock-free engagement), verification (without adding additional sensors, torque is distributed through P1P3, and engagement is verified by speed), and holding (after ensuring the clutch is physically engaged, a small current is applied to the coil to enter holding mode). The vehicle controller (HCU) sends commands, such as clutch engagement commands (which can also be understood as parallel engagement commands), to the motor controller (PEU). Upon receiving the command, the PEU controls the speed of the generator and drive motor, and collects speed data to create conditions for clutch engagement. Whether engagement is successful or unsuccessful, the PEU feeds back information to the HCU, without requiring a clutch controller (CCU). This invention solves the problem that insufficient engagement conditions in existing dog clutch control can lead to "false engagement" and trigger runaway; by integrating the CCU function into the PEU, the cost and weight of the dog clutch and its corresponding control system are reduced.

[0031] Specifically, in the unengaged state, an adjustment process is first performed to create conditions for successful clutch engagement. This includes: the motor controller acquiring the speed output by the drive motor to the vehicle wheels and calculating the engagement speed ratio to obtain the speed r1 at the drive motor end of the clutch. Here, the speed ratio can be understood as the transmission ratio of a series of transmission components from the drive motor to the clutch; the motor controller controls the generator to adjust the speed r2 at the generator end of the clutch through a speed loop (here, the speed loop can be understood as speed adjustment under PID feedback mechanism control), so that there is a difference D between the speeds r1 and r2 at both ends of the clutch, and this difference D is not zero.

[0032] This difference D is equivalent to artificially introducing a speed difference between the two ends of the clutch. The reason for this design is that if the speed difference between the two ends of the clutch, r1 and r2, is zero, the two ends of the clutch can be considered to be in a relatively static state. However, when the clutch engages (strictly speaking, after the adjustment is completed), it cannot be guaranteed that the meshing teeth at both ends of the clutch are in the optimal engagement state of tooth tip to tooth root. If the meshing teeth at both ends of the clutch are tooth tip to tooth tip, in this relatively static state, the clutch can never be engaged. Therefore, this invention can use this speed difference to gradually adjust the tooth tips of the meshing teeth at both ends of the clutch to be staggered, thereby achieving successful meshing of the meshing teeth at both ends.

[0033] Preferably, the upper limit of the target difference D can be set according to the tooth thickness and tooth clearance of the clutch engagement teeth, and the lower limit of the target difference D can be set according to the desired clutch engagement time. In a preferred embodiment, the target difference D can be set to 35 rpm.

[0034] After the adjustment is completed, the result needs to be evaluated to see if the ideal engagement state has been achieved. Specifically, it is determined whether the actual difference n between the speeds r1 and r2 at both ends of the clutch is within a preset speed difference range and lasts for a preset time. The target difference D is within the preset speed difference range (preferredly, a fluctuation value is set, and the target difference D is adjusted by positive or negative fluctuation to obtain the preset speed difference range. For example, if the target difference D is 35 rpm, then the preset speed difference range is 20 rpm ≤ |n| ≤ 50 rpm). If it is within the preset speed difference range, the adjustment is successful, and engagement can continue; if it is not within the preset speed difference range, the adjustment has failed, and the above adjustment process continues.

[0035] After successful adjustment, engagement occurs, which is the meshing process of the clutch teeth. This includes: the motor controller controlling the generator to adjust the torque at the generator end of the clutch using a torque loop, so that the difference between the speeds r1 and r2 at both ends of the clutch is zero; the clutch actuates to couple the engine and the drive motor. Speed ​​loop control is not used for the generator here because torque control can be achieved by controlling the current magnitude. That is, in the dynamic adjustment process of continuously adjusting the speed to make the speed difference with the drive motor zero, it can be achieved simply by increasing or decreasing the current. For the generator, the change in kinetic energy is small. If speed loop control were used instead, the speed would need to be directly changed each time for dynamic adjustment, which could potentially cause a strong impact between the two meshing teeth during engagement.

[0036] After engagement, it is necessary to initially determine whether the clutch engagement was successful. Specifically, it is necessary to determine whether the actual difference n between the speeds r1 and r2 at both ends of the clutch is less than a preset speed difference threshold and remains so for a preset time. The preset speed difference threshold here is set for the fluctuation error when the speed difference is 0, not for the fluctuation error of the target difference D in the adjustment stage. Therefore, the preset speed difference threshold here is usually less than the lower limit of the preset speed difference range in the adjustment stage, preferably 10 rpm.

[0037] 1) If not, it means that the engagement has failed. Then, try to engage the clutch again, or disengage the clutch directly. The difference is: if the engagement lasts for less than a preset time, try to engage the clutch again; if the engagement lasts for more than or equal to the preset time, abandon the clutch engagement.

[0038] 2) If yes, it means the clutch engagement is successful. At this point, the clutch engagement state can be maintained to complete the clutch engagement. Further, a re-engagement verification can be performed. This includes: first, the motor controller distributes the torque T1, which was entirely output by the drive motor in the disengaged state, to the generator and drive motor; then, it determines whether the actual difference n between the speeds r1 and r2 at both ends of the clutch is less than a preset speed difference threshold.

[0039] The principle behind the re-engagement verification is as follows: If the drive motor is coupled to the engine (successful engagement), even if the torque T1 output by the drive motor is distributed to the generator and drive motor in the disengaged state, there will not be a large difference between the speeds r1 and r2 at both ends of the clutch because it is now in parallel mode. If there is a difference, it is a normal deviation (a small difference). However, if the drive motor is not coupled to the engine (engagement failure), the generator speed will suddenly increase because the engine is in a torque-reduced state. At this time, a larger difference will appear between the speeds r1 and r2 at both ends of the clutch.

[0040] Therefore, if the actual difference n between the speeds r1 and r2 at both ends of the clutch is less than the preset speed difference threshold, it indicates successful engagement, and the clutch remains engaged, completing the clutch engagement. If the actual difference n between the speeds r1 and r2 at both ends of the clutch is greater than the preset speed difference threshold, it indicates a significant change in the difference between the speeds r1 and r2 at both ends of the clutch, suggesting that the previous engagement was a false engagement and the engagement was unsuccessful. In this case, the motor controller redistributes the torque T1 entirely to the generator and uses a torque loop to control the generator speed, abandoning clutch engagement.

[0041] Here, when allocating the torque T1 of the drive motor, the torque allocated to the drive motor is greater than the torque allocated to the generator. This ensures that even if the engagement is not actually achieved, the power transmitted to the vehicle wheels is not significantly reduced compared to before the allocation, as the torque allocated to the drive motor is not significantly reduced. Therefore, for the driver, this does not result in a noticeable change in vehicle speed, and the verification does not affect the driving experience. For example, the motor controller allocates 10% of the torque T1 output by the drive motor in the disengaged state to the generator and 90% to the drive motor.

[0042] See appendix Figure 2 The following provides a complete preferred embodiment of the present invention.

[0043] S10 adjustment.

[0044] S101: The HCU determines that parallel operation has been entered, the engine torque is reduced (0 torque control), and a parallel operation command is sent to the PEU;

[0045] S102: In series mode, motor P1 is controlled by speed loop; P1 maintains speed loop control and adjusts the speed difference between the two sides of the clutch according to the speed of motor P3, with the speed difference control target being 35 rpm.

[0046] S11: Determine whether the absolute value of the speed difference between the two ends of the clutch satisfies 20rpm≤|n|≤50rpm, and maintain it for 150ms;

[0047] If S111 is: Enter the S20 action phase;

[0048] If S112 is not: return to S102 and continue the investigation.

[0049] S20 action.

[0050] S201: P1 motor switches to torque control mode. PEU controls the speed of P1 through the torque loop based on the speed of P3. The speed difference control target is 0.

[0051] S202: The clutch coil is energized (operating current), which pushes the clutch moving end to move.

[0052] S21: Determine whether the absolute value of the speed difference between the two ends of the clutch satisfies |n|≤10rpm, and maintain this for 300ms;

[0053] If S211 is true: proceed to the S30 verification stage;

[0054] If S212 is not valid and less than 600ms has elapsed: return to 201, continue the adjustment, and keep the clutch coil energized;

[0055] If S213 fails and exceeds 600ms: an error is reported, the parallel connection is terminated, the coil is de-energized, and the error information is fed back to the HCU.

[0056] S30 verification.

[0057] S301: Based on the torque requirement of P3 from the HCU, the engagement ratio is converted to 90% output for P3 and 10% output for P1, with the process lasting 300ms.

[0058] S31: Determine whether the absolute value of the speed difference between the two ends of the clutch satisfies |n|≤10rpm during the entire S30 step;

[0059] If S311 is: Enter the S40 holding phase;

[0060] If S312 fails: an error is reported and the parallel connection is exited. After the torque is switched to P3 output 100%, P1 performs torque loop 0 speed control, the coil is de-energized, and an error message is reported to the HCU.

[0061] S40 remains unchanged.

[0062] S401: Reduce clutch coil current (holding current) and report to HCU that clutch engagement was successful and parallel mode has been entered.

[0063] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method of engagement control of a dog clutch of a hybrid transmission, characterized by, The method comprises the following steps: In the unengaged state, a difference adjusting process is performed, comprising: the motor controller acquires the rotational speed of the driving motor output to the vehicle wheels, and acquires the rotational speed r1 of the driving motor end of the clutch according to the rotational speed ratio; the motor controller controls the generator to adjust the rotational speed r2 of the generator end of the clutch in the rotational speed loop, so that the difference between the rotational speed r1 and the rotational speed r2 of the two ends of the clutch is the target difference D, and D≠0; An engagement action is performed, comprising: the motor controller controls the generator to adjust the torque of the generator end of the clutch in the torque loop, so that the difference between the rotational speed r1 and the rotational speed r2 of the two ends of the clutch is 0; the clutch engagement action realizes the coupling of the engine and the driving motor; It is judged whether the actual difference n between the rotational speed r1 and the rotational speed r2 of the two ends of the clutch is less than a preset rotational speed difference threshold and lasts for a first preset time; If not, the engagement action is performed again; If yes, the clutch engagement state is maintained, and the clutch engagement is completed. And The judgment of whether the actual difference n between the rotational speed r1 and the rotational speed r2 of the two ends of the clutch is less than a preset rotational speed difference threshold and lasts for a first preset time, and the clutch engagement state is maintained, and the clutch engagement is completed if yes, comprises: If yes, a verification process is performed, comprising: the motor controller distributes the torque T1 output by the driving motor in the unengaged state to the generator and the driving motor, and the torque distributed to the driving motor is greater than the torque distributed to the generator; It is judged whether the actual difference n between the rotational speed r1 and the rotational speed r2 of the two ends of the clutch is less than a preset rotational speed difference threshold; If yes, the clutch engagement state is maintained, and the clutch engagement is completed; If not, the torque T1 is distributed to the generator, and the generator speed is controlled in the torque loop, and the clutch engagement is abandoned.

2. The engagement control method of a dog clutch according to claim 1, characterized by, The method further comprises the following before the engagement action is performed: It is judged whether the actual difference n between the rotational speed r1 and the rotational speed r2 of the two ends of the clutch is within a preset rotational speed difference range and lasts for a second preset time, and the target difference D is within the preset rotational speed difference range; If not, the difference adjusting process is continued; If yes, the engagement action is performed.

3. The engagement control method of a dog clutch according to claim 1, characterized by, The motor controller distributing the torque T1 output by the driving motor in the unengaged state to the generator and the driving motor comprises: The motor controller distributes 10% of the torque T1 output by the driving motor in the unengaged state to the generator, and 90% to the driving motor.

4. The engagement control method of a dog clutch according to claim 1, characterized by The upper limit of the target difference D is set according to the tooth thickness and the tooth gap size of the engagement teeth of the clutch, and the lower limit of the target difference D is set according to the expected clutch engagement time.

5. The engagement control method of a dog clutch according to claim 4, characterized by The target difference D is 35 rpm.

6. The engagement control method of a dog clutch according to claim 4, characterized by The judgment of whether the actual difference n between the rotational speed r1 and the rotational speed r2 of the two ends of the clutch is within a preset rotational speed difference range and lasts for a second preset time comprises: A fluctuation value is set, and the preset rotational speed difference range is obtained by taking the target difference D plus and minus the fluctuation value.

7. The engagement control method of the dog clutch according to claim 1, characterized by, The preset rotational speed difference threshold is set according to the tooth thickness and the tooth gap size of the engagement teeth of the clutch; The preset rotational speed difference threshold is less than the preset rotational speed difference range.

8. The engagement control method of a dog clutch according to claim 1, characterized by whether an actual difference n between the rotational speed r1 and the rotational speed r2 is less than a preset rotational speed difference threshold value and lasts for a first preset time; if not, the re-performing the engagement action comprises: if not, and lasting for less than a third preset time, re-performing the engagement action; if not, and lasting for greater than or equal to the third preset time, giving up the clutch engagement.

9. The engagement control method of the dog clutch according to claim 8, characterized by, the giving up the clutch engagement comprises: the motor controller feeding back an engagement error information to a vehicle controller; the completing the clutch engagement comprises: the motor controller feeding back an engagement success information to the vehicle controller; before the performing the difference adjusting process in the unengaged state, the method further comprises: the vehicle controller sending a clutch engagement instruction to the motor controller.

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