# US 10,371,256 B2 · Vehicle lock-up clutch control device and lock-up clutch control method

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- Number: US 10,371,256 B2
- Document ID: US10371256B2
- Status: Granted
- Kind: B2
- Application number: 15/753,705
- Filed: 2016-08-12
- Published: 2018-08-30
- Granted: 2019-08-06
- Earliest claimed: 2015-08-24
- Assignees: JATCO Ltd; Nissan Motor Co., Ltd.
- Applicants: JATCO Ltd; Nissan Motor Co., Ltd.
- Inventors: Toshimitsu Araki; Seiji Kasahara; Hideshi Wakayama; Kouji Saitou; Hiroyasu Tanaka
- Web page: https://patentgrep.com/patent/US10371256B2

## CPC

- F16H 61/143: {using electric control means}
- F16D 48/06: Control by electric or electronic means, e.g. of fluid pressure
- F16H 59/14: Inputs being a function of torque or torque demand
- B60Y 2300/421: Control of lock-up type clutches, e.g. in a torque converter
- F16D 48/02: Control by fluid pressure
- F16D 2500/10412: Transmission line of a vehicle
- F16D 2500/10462: Dog-type clutch
- F16D 2500/3024: Pressure
- F16D 2500/30421: Torque of the output shaft
- F16D 2500/3065: Torque of the engine
- F16D 2500/3166: Detection of an elapsed period of time
- F16D 2500/5012: Accurate determination of the clutch positions, e.g. treating the signal from the position sensor, or by using two position sensors for determination
- F16D 2500/50236: Adaptations of the clutch characteristics, e.g. curve clutch capacity torque - clutch actuator displacement
- F16D 2500/7041: Position
- F16H 59/42: Input shaft speed
- F16H 59/44: dependent on machine speed {, e.g. the vehicle speed} (F16H59/46 takes precedence)
- F16H 2059/147: {Transmission input torque, e.g. measured or estimated engine torque}
- F16H 2061/0087: {Adaptive control, e.g. the control parameters adapted by learning}
- F16H 2061/146: {for smoothing gear shift shock}
- F16H: GEARING
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- B60Y: INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY

## Abstract

In a vehicle on which a torque converter having a lock-up clutch is mounted between an engine and a transmission, a meet point learning controller is provided to perform learning control for obtaining a learning value based on information on a meet point at which the lock-up clutch starts torque transmission. The meet point learning controller estimates a LU transmission torque based on a difference between an engine torque signal value and a torque converter transmission torque when the lock-up clutch moves from a non-engaged state to an engaged state during traveling of the vehicle, and uses, as the meet point information, a meet point detection pressure at a time when the LU transmission torque estimated value is determined to have entered an upward trend.

## Claims

### Claim 1

In a vehicle on which a torque converter having a lock-up clutch is mounted between an engine and a transmission, a lock-up clutch control device of the vehicle comprises:
a lock-up controller that performs engagement control for the lock-up clutch; and
a meet point learning controller that performs learning control for obtaining a learning value based on information on a meet point at which the lock-up clutch starts torque transmission,
wherein the meet point learning controller estimates a lock-up transmission torque based on a difference between an engine torque and a torque converter transmission torque when the lock-up clutch moves from a non-engaged state to an engaged state during traveling of the vehicle, and uses, as the meet point information, a meet point detection pressure at a time when the lock-up transmission torque estimated value is determined to have entered an upward trend, and
wherein the meet point learning controller determines that the lock-up transmission torque estimated value has entered the upward trend, when a variation in the lock-up transmission torque estimated value per unit time exceeds an edge detection threshold value that represents a start of a monotonic increase.

### Claim 2 (depends on 1)

A lock-up clutch control device of the vehicle as recited in claim 1, wherein:
the meet point learning controller estimates a meet point estimation pressure at which the lock-up clutch starts torque transmission, based on an extension line obtained when connecting a plurality of hydraulic points on a build-up characteristic line of the lock-up transmission torque estimated value, compares the meet point detection pressure and the meet point estimation pressure, and takes the meet point detection pressure in as the meet point information for obtaining the learning value, when a difference between the meet point detection pressure and the meet point estimation pressure is less than a predetermined value.

### Claim 3 (depends on 2)

A lock-up clutch control device of the vehicle as recited in claim 2, wherein:
the meet point learning controller connects a first hydraulic point which has reached a first predetermined ratio with respect to a torque converter input torque of the lock-up clutch kept in a completely engaged state and a second hydraulic point which has reached a second predetermined ratio greater than the first predetermined ratio, and sets, as the meet point estimation pressure, information on a hydraulic pressure corresponding to an intersection point of an extension line obtained when connecting the first hydraulic point and the second hydraulic point and a coordinate line on which the lock-up transmission torque estimated value is zero.

### Claim 4 (depends on 3)

A lock-up clutch control device of the vehicle as recited in claim 3, wherein:
the meet point learning controller sets the first predetermined ratio and the second predetermined ratio less than or equal to 50% of the torque converter input torque.

### Claim 5 (depends on 1)

A lock-up clutch control device of the vehicle as recited in claim 1, wherein:
the lock-up controller calculates an initial pressure to be supplied to the lock-up clutch by subtracting an offset pressure from the learning value determined based on the meet point detection pressure, and performs the engagement control for the lock-up clutch by using the calculated initial pressure.

### Claim 6

In a vehicle on which a torque converter having a lock-up clutch is mounted between an engine and a transmission, the vehicle equipped with a lock-up controller that performs engagement control for the lock-up clutch, and a meet point learning controller that performs learning control for obtaining a learning value based on information on a meet point at which the lock-up clutch starts torque transmission, a lock-up clutch control method of the vehicle comprises:
estimating a lock-up transmission torque based on a difference between an engine torque and a torque converter transmission torque when the lock-up clutch moves from a non-engaged state to an engaged state during traveling of the vehicle;
using, as the meet point information, a meet point detection pressure at a time when the lock-up transmission torque estimated value is determined to have entered an upward trend; and
determining that the lock-up transmission torque estimated value has entered the upward trend, when a variation in the lock-up transmission torque estimated value per unit time exceeds an edge detection threshold value that represents a start of a monotonic increase.