# US 8,465,394 B2 · Method for operating a transmission device of a vehicle drivetrain

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- Number: US 8,465,394 B2
- Document ID: US8465394B2
- Status: Granted
- Kind: B2
- Application number: 13/387,866
- Filed: 2010-07-22
- Published: 2012-05-31
- Granted: 2013-06-18
- Earliest claimed: 2009-08-06
- Assignees: ZF Friedrichshafen AG
- Applicants: Ruben Cuppers; Werner Fuchs; Thilo Schmidt
- Inventors: Ruben Cuppers; Werner Fuchs; Thilo Schmidt
- Web page: https://patentgrep.com/patent/US8465394B2

## CPC

- F16H 61/0403: {Synchronisation before shifting}
- B60W 10/06: including control of combustion engines
- B60W 10/115: with planetary gears
- B60W 30/188: Controlling power parameters of the driveline, e.g. determining the required power
- F16H 63/502: {for smoothing gear shifts}
- B60W 2710/0666: Engine torque
- F16H 61/686: with orbital gears
- F16H 2200/006: the gear ratios comprising eight forward speeds
- F16H 2200/2012: with four sets of orbital gears
- F16H 2200/2043: with five engaging means
- F16H 2200/2064: using at least one positive clutch, e.g. dog clutch
- F16H 2200/2094: using positive clutches, e.g. dog clutches
- F16H: GEARING
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT

## Abstract

A method of operating a transmission of a vehicle drive-train that comprises frictional shifting elements and an interlocking shifting element. In the neutral operating condition of the transmission, and in the case of an operating condition variation of the vehicle drive-train in which, when it is required to establish the force flow in the transmission, the interlocking shifting element is to be changed from a disengaged to an engaged operating condition, by increasing the transmission capacities of at least two frictional shifting elements which have to be engaged for producing the force flow, a rotational speed difference in the area of the interlocking shifting element is determined, and a drive torque of a drive machine is adjusted to a level that brings the speed difference within a predefined range at which the interlocking shifting element is approximately synchronized and can therefore be engaged.

## Claims

### Claim 1

A method of operating a transmission device (10) of a vehicle drive-train (1) that comprises a plurality of frictional shifting elements (A, C to E) and at least one interlocking shifting element (B) for obtaining various gear ratios (“1” to “R”), wherein in a neutral operating condition (“N”) of the transmission device (10), in which a force flow is interrupted in an area of the transmission device (10), and in a case of an operating condition variation of the vehicle drive-train (1) in which, when required to establish the force flow in the transmission device (10), the at least one interlocking shifting element (B) has to be changed from a disengaged to an engaged operating condition, the method comprising the steps of:
increasing transmission capacities of at least two frictional shifting elements (A, C), which have to be engaged to produce the force flow, to a level at which the frictional shifting elements (A, C) operate in a slip-free condition,
determining a rotational speed difference (nd_B) in an area of the interlocking shifting element (B), and
adjusting a drive torque (m_mot) of a drive machine (9) to a level that brings the rotational speed difference (nd_B) in the area of the interlocking shifting element (B) to within a predefined speed difference range (nd_Bo, nd_Bu) such that within the predefined speed difference range (nd_Bo, nd_Bu), the interlocking shifting element (B) is in an at least an approximately synchronized condition and can thus be engaged.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising a step of reducing the transmission capacities of the two frictional shifting elements (A, C) essentially to zero before engaging the interlocking shifting element (B).

### Claim 3 (depends on 2)

The method according to claim 2, further comprising a step of actuating one of the two frictional shifting elements (C) with an actuating force, at an engagement time (T10) of the interlocking shifting element (B) and after the engagement thereof, to immediately increase the transmission capacity of the frictional shifting element (C).

### Claim 4 (depends on 3)

The method according to claim 3, further comprising a step of adjusting the drive torque (m_mot) of the drive machine (9) from the engagement time (T10) of the interlocking shifting element (B) to a required level that is dependant on the operating condition.

### Claim 5 (depends on 4)

The method according to claim 4, further comprising a step of defining the operating-condition-dependent level of the drive torque (m_mot) to be equivalent to an idling level of the drive torque (n_mot) of the drive machine (9).

### Claim 6 (depends on 1)

The method according to claim 1, further comprising a step of determining the speed difference (nd_B), in the area of the interlocking shifting element (B), with two speed sensors (13, 14), and arranging one of the two speed sensors (13) on a transmission input side and arranging the other of the two speed sensors (14) on the transmission output side.

### Claim 7

A method of operating a transmission in a drive train of a vehicle when shifting the transmission from a neutral operating condition, in which a flow of drive through the transmission is interrupted and an interlocking shift element (B) is disengaged, to a drive operating condition in which the flow of drive through the transmission is established at least by engagement of the interlocking shift element (B), the transmission comprises the interlocking shift element (B) and a plurality of frictional shift elements (A, C, D, E) which are selectively engagable to implement a variety of gear ratios, the method comprising the steps:
increasing transmission capacities of at least two of the plurality of frictional shifting elements (A, C), which are engaged to facilitate the flow of drive, to a level at which the two of the plurality of frictional shifting elements (A, C) substantially operate in a slip-free condition;
determining a rotation speed difference (nd_B) at the interlocking shifting element (B);
adjusting a drive torque (m_mot) of a drive machine (9) to a level at which the rotational speed difference (nd_B) at the interlocking shifting element (B) is within a predefined rotational speed difference range (nd_Bo, nd_Bu) and the interlocking shifting element (B) is at least substantially synchronized; and
engaging the interlocking shifting element (B).