US-20260126087-A1 - DOG CLUTCH ENGAGEMENT CONTROL SYSTEM

US20260126087A1US 20260126087 A1US20260126087 A1US 20260126087A1US-20260126087-A1

Abstract

A clutch actuator relatively moves a first clutch member and a second clutch member relative to each other in an axial direction. A phase difference sensor detects a phase difference between the first and second clutch members. A controller executes a synchronization operation that gradually decreases an input-output rotational speed difference until it reaches a target rotational speed difference and detects a current latest engagement timing based on an output of the phase difference sensor. After an adjustment reference time point, at which the input-output rotational speed difference reaches a phase-difference-detectable rotational speed difference that allows the phase difference sensor to detect the phase difference, the controller adjusts the phase difference by changing a change characteristic of the input-output rotational speed difference such that one of future engagement timings coincides with a target completion time point, based on information obtained at an arbitrary phase difference detection time point.

Inventors

Daisuke NAKANISHI
Yoshinori Kato
Yasuhiro Shikata
Kazushi Nakatani

Assignees

DENSO CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251219
Priority Date: 20231030

Claims (9)

1 . A dog clutch engagement control system, comprising: a dog clutch that includes: a first clutch member which is coupled to an input shaft and has a plurality of first engagement teeth arranged in a circumferential direction of the dog clutch; and a second clutch member which is coupled to an output shaft and has a plurality of second engagement teeth arranged in the circumferential direction, wherein the plurality of second engagement teeth are configured to engage with the plurality of first engagement teeth, and the dog clutch is configured to switch between an engaged state, in which the first clutch member and the second clutch member are engaged with each other, and a disengaged state, in which the first clutch member and the second clutch member are disengaged from each other; a clutch actuator that is configured to drive the dog clutch and thereby to shift the dog clutch between the engaged state and the disengaged state; a phase difference sensor that is configured to detect a phase difference between the first clutch member and the second clutch member; and a controller that includes at least one of (i) a circuit and (ii) a processor with a memory storing computer program code executable by the processor, wherein the controller is configured to: control an input-output rotational speed difference, which is a difference between a rotational speed of the input shaft and a rotational speed of the output shaft; in response to an engagement instruction, which instructs to shift the dog clutch from the disengaged state into the engaged state, execute a synchronization operation to gradually decrease the input-output rotational speed difference until the input-output rotational speed difference reaches a target rotational speed difference at which the dog clutch is shiftable into the engaged state; in the synchronization operation, with respect to an engagement timing, at which the phase difference reaches an allowable phase difference that allows the dog clutch to be shifted into the engaged state, detect a current latest engagement timing, which is the engagement timing detected most recently, based on an output of the phase difference sensor; and output a drive instruction to the clutch actuator to cause the dog clutch to be shifted into the engaged state at one of a plurality of future engagement timings, each of which is subsequent to a timing at which the input-output rotational speed difference reaches the target rotational speed difference, wherein: after reaching an adjustment reference time point, at which the input-output rotational speed difference reaches a phase-difference-detectable rotational speed difference that allows the phase difference sensor to detect the phase difference, the controller is configured to adjust the phase difference between the first clutch member and the second clutch member based on information, which is obtained at an arbitrary phase difference detection time point where an arbitrary phase difference is detected according to the output of the phase difference sensor, by changing a change characteristic of the input-output rotational speed difference, such that the one of the plurality of future engagement timings coincides with a target completion time point that is a time point at which a target completion time length elapses from the adjustment reference time point.
2 . The dog clutch engagement control system according to claim 1 , wherein: a time rate of change of the input-output rotational speed difference is defined as a gradient, and the gradient in a period from the adjustment reference time point to the arbitrary phase difference detection time point is defined as an initial gradient, and the controller is configured to calculate a target gradient, which is a target value of the gradient, based on the information obtained at the arbitrary phase difference detection time point, and the controller is configured to change from the initial gradient to the target gradient.
3 . The dog clutch engagement control system according to claim 2 , wherein the controller is configured to calculate the target gradient based on: the target completion time length; a time length from the adjustment reference time point to the arbitrary phase difference detection time point; the phase difference that is detected at the arbitrary phase difference detection time point; a target phase difference at a time of shifting the dog clutch into the engaged state; the input-output rotational speed difference at the arbitrary phase difference detection time point; and the target rotational speed difference.
4 . The dog clutch engagement control system according to claim 3 , wherein the controller is configured to calculate the target gradient such that, during a period from the arbitrary phase difference detection time point to the target completion time point, a time integral of a converted value, which is obtained by converting the input-output rotational speed difference into a phase difference change rate, coincides with a phase difference that is obtained by adding, to an integer multiple of a pitch angle of the plurality of first engagement teeth and the plurality of second engagement teeth, a difference between the target phase difference at the time of shifting the dog clutch into the engaged state and the phase difference detected at the arbitrary phase difference detection time point.
5 . The dog clutch engagement control system according to claim 1 , wherein the phase difference, which is detected at the arbitrary phase difference detection time point, is a phase difference that enables the dog clutch to be shifted into the engaged state.
6 . The dog clutch engagement control system according to claim 1 , wherein the controller is configured to change the target rotational speed difference based on the information obtained at the arbitrary phase difference detection time point.
7 . The dog clutch engagement control system according to claim 1 , wherein: the controller is configured to start a preliminary operation of the clutch actuator at a time point that precedes the target completion time point by a predetermined preliminary operation time length; and in a case where a factor causing an operational delay of the clutch actuator is generated, the controller is configured to correct the target completion time length in accordance with an operation delay time length of the operation delay.
8 . The dog clutch engagement control system according to claim 2 , wherein: the arbitrary phase difference detection time point is one of a plurality of arbitrary phase difference detection time points, and the phase difference is detected at each of the plurality of arbitrary phase difference detection time points during a period from the adjustment reference time point to an arrival timing, at which the input-output rotational speed difference reaches the target rotational speed difference; and the controller is configured to update the target gradient, which is calculated at a previous one of the plurality of arbitrary phase difference detection time points, to the target gradient, which is calculated at a current one of the plurality of arbitrary phase difference detection time points.
9 . A dog clutch engagement control system, comprising: a dog clutch that includes: a first clutch member which is coupled to an input shaft and has a plurality of first engagement teeth arranged in a circumferential direction of the dog clutch; and a second clutch member which is coupled to an output shaft and has a plurality of second engagement teeth arranged in the circumferential direction, wherein the plurality of second engagement teeth are configured to engage with the plurality of first engagement teeth directly or indirectly via a relay member, and the dog clutch is configured to switch between an engaged state, in which the first clutch member and the second clutch member are engaged with each other, and a disengaged state, in which the first clutch member and the second clutch member are disengaged from each other; a clutch actuator that is configured to relatively move the first clutch member and the second clutch member relative to each other in an axial direction of the dog clutch, or, relatively move the relay member in the axial direction relative to the first clutch member and the second clutch member in a case where the relay member is used; a phase difference sensor that is configured to detect a phase difference between the first clutch member and the second clutch member; and a controller that is configured to: control an input-output rotational speed difference, which is a difference between a rotational speed of the input shaft and a rotational speed of the output shaft; in response to an engagement instruction, which instructs to shift the dog clutch from the disengaged state into the engaged state, execute a synchronization operation to gradually decrease the input-output rotational speed difference until the input-output rotational speed difference reaches a target rotational speed difference at which the dog clutch is shiftable into the engaged state; in the synchronization operation, with respect to an engagement timing, at which the phase difference reaches an allowable phase difference that allows the dog clutch to be shifted into the engaged state, detect a current latest engagement timing, which is the engagement timing detected most recently, based on an output of the phase difference sensor; and output a drive instruction to the clutch actuator to cause the dog clutch to be shifted into the engaged state at one of a plurality of future engagement timings, each of which is subsequent to a timing at which the input-output rotational speed difference reaches the target rotational speed difference, wherein: after reaching an adjustment reference time point, at which the input-output rotational speed difference reaches a phase-difference-detectable rotational speed difference that allows the phase difference sensor to detect the phase difference, the controller is configured to adjust the phase difference between the first clutch member and the second clutch member based on information, which is obtained at an arbitrary phase difference detection time point where an arbitrary phase difference is detected according to the output of the phase difference sensor, by changing a change characteristic of the input-output rotational speed difference, such that the one of the plurality of future engagement timings coincides with a target completion time point that is a time point at which a target completion time length elapses from the adjustment reference time point.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation application of International Patent Application No. PCT/JP2024/036891 filed on Oct. 16, 2024, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2023-185557 filed on Oct. 30, 2023. The entire disclosures of all of the above applications are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a dog clutch engagement control system. BACKGROUND Previously, a dog clutch engagement control system is known. This dog clutch engagement control system engages an input shaft and an output shaft, which respectively rotate at different speeds in a disengaged state. For example, one previously proposed technology predicts a future engagement timing based on a plurality of past engagement timings detected based on an output of a phase difference sensor. A controller executes a synchronization operation such that a rotational speed difference between an electric motor and an axle of a vehicle (i.e., an input-output rotational speed difference) reaches a predetermined target rotational speed difference. Then, a clutch actuator is preliminarily driven such that the dog clutch is engaged at a predicted engagement timing after the input-output rotational speed difference reaches the target rotational speed difference. SUMMARY According to one aspect of the present disclosure, there is provided a dog clutch engagement control system that may include a dog clutch, a clutch actuator, a phase difference sensor and a controller. The dog clutch may include a first clutch member and a second clutch member. The first clutch member may be coupled to an input shaft and may have a plurality of first engagement teeth arranged in a circumferential direction of the dog clutch. The second clutch member may be coupled to an output shaft and may have a plurality of second engagement teeth arranged in the circumferential direction. The plurality of second engagement teeth may be configured to engage with the plurality of first engagement teeth directly or indirectly via a relay member. The dog clutch may be configured to switch between an engaged state, in which the first clutch member and the second clutch member are engaged with each other, and a disengaged state, in which the first clutch member and the second clutch member are disengaged from each other. The clutch actuator may be configured to relatively move the first clutch member and the second clutch member relative to each other in an axial direction of the dog clutch, or, relatively move the relay member in the axial direction relative to the first clutch member and the second clutch member in a case where the relay member is used. The phase difference sensor may be configured to detect a phase difference between the first clutch member and the second clutch member. The controller may include at least one of (i) a circuit and (ii) a processor with a memory storing computer program code executable by the processor. The controller may be configured to: control an input-output rotational speed difference, which is a difference between a rotational speed of the input shaft and a rotational speed of the output shaft; in response to an engagement instruction, which instructs to shift the dog clutch from the disengaged state into the engaged state, execute a synchronization operation to gradually decrease the input-output rotational speed difference until the input-output rotational speed difference reaches a target rotational speed difference at which the dog clutch is shiftable into the engaged state; in the synchronization operation, with respect to an engagement timing, at which the phase difference reaches an allowable phase difference that allows the dog clutch to be shifted into the engaged state, detect a current latest engagement timing, which is the engagement timing detected most recently, based on an output of the phase difference sensor; and output a drive instruction to the clutch actuator to cause the dog clutch to be shifted into the engaged state at one of a plurality of future engagement timings, each of which is subsequent to a timing at which the input-output rotational speed difference reaches the target rotational speed difference. After reaching an adjustment reference time point, at which the input-output rotational speed difference reaches a phase-difference-detectable rotational speed difference that allows the phase difference sensor to detect the phase difference, the controller may be configured to adjust the phase difference between the first clutch member and the second clutch member based on information, which is obtained at an arbitrary phase difference detection time point where an arbitrary phase difference is detected according to the output of the phase difference sensor, by changing a change characteristic of the input-output rotational speed difference, such that the one of the plurality of future en