DE102006019239A1 - Gear change control method for automatic gearbox unit, involves aligning target gear unilaterally with large speed gradient at beginning and with small speed gradients to coupling at end of synchronization - Google Patents

Abstract

The method involves controlling an electric machine for synchronization of the target gear in such a manner, that the output speed of the coupling of the target gear is unilaterally aligned, with large speed gradient at the beginning and with small speed gradients to the coupling at the end of the synchronization, in asymptotic manner to the output speed of the coupling.

Description

The The invention relates to a method for switching control of an automated Manual transmission, which is in a drive train of a motor vehicle arranged between an internal combustion engine and a final drive is provided with unsynchronisierten clutches, and whose input shaft can be operated with a motor and generator Electric machine is connected or connectable, wherein at a circuit from a load gear and in a target gear the synchronization of the Targeting done by means of the electric machine.

In a manual transmission occurs in a circuit between a load gear and a target gear after laying out the load gear at the target gear assigned and still open gear shift clutch on a speed difference, the before inserting the target gear, so before closing the relevant clutch must be compensated. this will commonly referred to as synchronization and is practical by a speed adaptation of the with the input shaft of the gearbox connected input-side part of the clutch. At a Upshifting rotates the input side of the clutch of the Target gear after laying the load gear faster than the output side Part of the clutch, allowing the input shaft for synchronization of the target gear delayed must become. In a downshift the input-side part of the clutch of the target gear rotates on the other hand, after laying out the load gear, it is slower than the output side Part of the clutch, allowing the input shaft for synchronization of the target gear has to be accelerated.

In a provided with synchronized clutches manual gearbox the synchronization of the respective target gear or the Target gear associated clutch via a friction ring synchronization device, the actual, mostly designed as a dog clutch, positive clutch upstream.

at the synchronization of the target gear is the at the clutch applied speed difference passively by the action of a switching force by a between two friction rings of the synchronizer generated friction torque balanced before the clutch under the effect of the switching force indented and thus the target gear can be inserted. Such lock-synchronized clutches However, they are relatively complicated and expensive. Also require synchronized clutches within the gearbox a relatively large one Space and thus increase the Dimensions and the weight of the gearbox. Due to the subject to wear Operation of the synchronizers is also the life limited the relevant gearbox.

in the In contrast, unsynchronized clutches are simple and compact design, inexpensive to manufacture, and exhibit when properly performed circuits a little wear and tear consequently a long service life. In one with unsynchronized However, clutches provided shift transmission is an active synchronization the respective target gear or the gearshift assigned to the target gear required. For this it is known, for example, to synchronize of the target gear, the input shaft of the gearbox in an upshift to decelerate by means of a transmission brake and a downshift by means of the internal combustion engine with at least partially closed Accelerate engine clutch. Also for this is the use a connected or connectable to the input shaft electric machine known, in comparison to a transmission brake and an internal combustion engine faster and more precisely controllable, and with the input shaft delayed both in generator mode and in motor mode Operation can be accelerated.

In the DE 198 49 156 A1 is a drive train of a motor vehicle of the type described, in which a motor and a generator operable electric machine with the input shaft of an automated transmission is in communication. In a first embodiment of the drive train, the rotor of the electric machine is non-rotatably connected to the input shaft, and the rotatably mounted stator is connected via a gear pair with the output shaft of the gearbox in connection.

hereby can the input shaft of the gearbox in a circuit for Synchronization of the respective target gear by means of the electric machine be accelerated or decelerated as needed relative to the output shaft. In a second embodiment This known drive train is the rotor of the electric machine rotatably connected to the sun gear of a planetary gear, and the Stator is on the housing side established. The planet carrier of the planetary gear is non-rotatable with the drive shaft of the internal combustion engine connected, and the ring gear of the planetary gear is connected via a pair of gears with the output shaft of the gearbox in conjunction. hereby can the input shaft of the gearbox in a circuit for synchronization the respective target gear by means of the electric machine relative to the drive shaft of the engine and to the output shaft the transmission can be accelerated or decelerated as needed.

Another drive train of a motor vehicle of the type in question is from the DE 199 34 696 A1 and the DE 101 52 471 A1 known. In this drive train, the input shaft of the gearbox is connected via a planetary gear with an internal combustion engine and an electric motor in combination. The ring gear of the planetary gear is rotatably connected to the drive shaft of the internal combustion engine. The rotor of the electric machine is rotatably connected to the sun gear of the planetary gear, whereas the stator of the electric machine is fixed on the housing side. The planet carrier of the planetary gear is rotatably coupled to the input shaft of the gearbox.

Between the sun gear and the planet carrier of the planetary gear is a lock-up clutch arranged in normal driving, ie outside of start-up and switching operations, closed is. With the lock-up clutch open can the input shaft of the gearbox in a circuit for Synchronization of the respective target gear by means of the electric machine relative if necessary accelerated to the drive shaft of the internal combustion engine or delayed become.

In such powertrains, the input shaft of the gearbox for synchronization of the target gear or the target gear associated clutch is delayed by the electric machine at an upshift and accelerated at a downshift in a shift from a load gear to a target gear until the speed difference .DELTA.n _SK = n _{SK_A} - n _{SK_E} between the output-side part and the input-side part of the clutch is sufficiently small, so that the clutch engaged and thus the target gear can be engaged.

If the speed difference Δn _SK at the clutch is too great, the clutches of the clutch are rejected when engaged, resulting in so-called "ratcheting" of the clutch, resulting in comfort-reducing noise and high wear on the claw of the clutch, delaying the engagement In the case of a largely _equal speed between the input-side part and the output-side part of the clutch (n _{SK_A} = n _{SK_E} ), the claws of the two clutch _halves can abut each other, so that engagement of the clutch is also impossible and at very small speed difference .DELTA.n _SK can only be delayed greatly.

According to previously known methods, the deceleration or acceleration of the input shaft is largely unregulated, ie with a constant speed gradient or with a constant torque of the electric machine. As a result, occurs when engaging the clutch on a comfort harmful shift shock M _jerk in the drive train, because of the equation M shock = dω SK_E / Dt · J SK_E is proportional to the conditional by the engagement rotational speed change d ω _{SK_E} / dt of the input-side part of the clutch or proportional to the input shaft connected thereto and the input side of the clutch applied moment of inertia J _{SK_E of} the drive-side drive train and the associated with this electric machine.

In front In this background, the present invention has the object underlying to provide a method with which in a powertrain of the type mentioned a circuit of a load gear in a target gear faster and more comfortable than previously possible feasible.

The solution this object is achieved by a method according to the features of the main claim, while advantageous embodiments and developments of the dependent claims are.

The invention is therefore based on a method for switching control of an automated gearbox, which is arranged in a drive train of a motor vehicle between an internal combustion engine and a final drive, which is provided with unsynchronisierten clutches, and whose input shaft is connected to a motor and generator operable electric machine or connectable , wherein in a circuit between a load gear and a target gear, the synchronization of the target gear by means of the electric machine. According to the method is also provided that the electric machine is controlled to synchronize the target gear such that the input-side speed n _{SK_E} the clutch of the target gear with large _{Drehzahlgradienten} dn _{SK_E} / dt at the beginning and with a small _{Drehzahlgradienten} dn _{SK_E} / dt asymptotically to the end of the synchronization _Output speed n _{SK_A of} the clutch SK is adjusted.

Due to the large speed _gradient dn _{SK_E} / dt at the beginning of the synchronization, the synchronization of the target gear is initially comparatively fast. Because of the later following smaller speed _gradient dn _{SK_E} / dt at the end of synchronization, the input side speed n _{SK_E} the clutch of the target gear is also approximated with low or vanishing speed difference Δn _SK = n _{SK_A} - n _{SK_E} to the output side speed n _{SK_A} the clutch SK, so that the following ing engagement of the clutch SK relatively easy and fast, so with little force and without a large shift shock M _jerk can be done. Due to the good control properties of the electric machine EM such a control is easily possible.

Admittedly, the deceleration or acceleration of the input-side part SK_E of the clutch SK and the input shaft of the gearbox connected to it take slightly more time than with a constant speed _gradient dn _{SK_E} / dt, due to the lighter and thus faster engagement of the clutch SK runs the entire circuit but faster. In addition, the shift comfort is increased by avoiding a strong shift shock M _jerk and high load peaks and vibration excitations avoided, so that the load and wear of the drive train, in particular the clutches, are significantly reduced.

To control the circuit _according to the invention, it is preferably provided that the input-side rotational speed n _{SK_E} and the output-side rotational speed n _{SK_A of} the clutch SK be determined, and from this the rotational speed difference Δn _SK = n _{SK_A} -n _{SK_E to} be _{synchronized is} calculated, and that the torque M _{EM of} the electric machine EM is reduced in proportion to the changing speed difference Δn _{SK of} the clutch.

This inevitably results in a speed _gradient dn _{SK_E} / dt of the input-side part SK_E of the shift clutch SK, which decreases towards the end of the synchronization, so that the input-side rotational speed n _{SK_E is} thus unavoidably _aligned asymptotically with the output-side rotational speed n _{SK_A of} the shift clutch SK. Consequently, the clutch SK can be subsequently engaged with very little or very vanishing speed difference Δn _SK = n _{SK_A} - n _{SK_E} .

To achieve this, the electric motor EM with a positive speed difference .DELTA.n _SK> 0, so during a downshift power tools and the drive torque M _EM> 0 is the electric motor EM reduced in proportion to the speed difference .DELTA.n _SK at the shift clutch SK. In contrast, the electric machine EM is operated at a negative speed difference .DELTA.n _SK <0, ie at an upshift, as a generator and reduces the drag torque M _EM <0 of the electric machine EM proportional to the speed difference .DELTA.n _SK on the clutch SK.

To accelerate the synchronization and thus the entire circuit is advantageously provided that the synchronization of the target gear initially takes place with a high constant drive or drag torque M _{EM of} the electric machine EM until a predetermined _limit speed difference .DELTA.n _{SK_Gr is} reached or fallen _below , and that only from this point on, the torque M _{EM of} the electric machine EM is reduced in proportion to the speed difference Δn _SK . In this case, the constant drive or drag torque M _{EM of} the electric machine used at the beginning of the synchronization can correspond to the maximum permissible torque M _{EM_max of} the electric machine EM, so that the limit _speed difference _{Δn SK_Gr is} reached as quickly as possible without overshooting the output-side speed n _{SK_A} by the input-side part Risk SK_E of the clutch SK.

Since it can come to a tooth-on-tooth contact of the two coupling halves SK_E, SK_A of the clutch SK due to the small or even vanishing speed difference Δn _SK , it is expedient that after reaching the synchronous _speed (n _{SK_E} = n _{SK_A} ) the engaging duration .DELTA.t _Einr for closing the clutch is determined, and that when exceeding a predetermined _{Grenzeinrückdauer} .DELTA.t _{Einr_Gr} the input-side part SK_E the clutch SK is acted upon by the electric machine EM with an angular momentum. As a result, a tooth-on-tooth gap contact of the two coupling halves SK_E and SK_A is enforced, which allows easy engagement of the clutch SK.

to Clarification of the invention, the description is a drawing with exemplary embodiments attached. In these shows

1 Speed curves at a clutch in an inventive synchronization of the target gear at an upshift,

2 Speed curves on a clutch in an inventive synchronization of the target gear in a downshift,

3 Speed curves at a clutch in a known synchronization of the target gear in an upshift, and

4 a sketch to illustrate the torque ratios when engaging a clutch.

In 3 are the speed _curves n _{SK_E} (t) and n _{SK_A} (t) of the input-side part SK_E and the output-side part SK_A a clutch SK of an automatic transmission for an upshift shown, in which the synchronization of the target gear takes place in a previously known manner. From time t0, the input side part becomes SK_E of the clutch SK by means of a connected to the input shaft of the gearbox electric machine EM by a constant generator torque M _EM with a constant speed _gradient dn _{SK_E} / dt delayed. At the time t1, the input side part SK_E of the shift clutch SK reaches the speed n _{SK_A of} the output side part SK_A, and the shift clutch SK is engaged.

Due to the different rotational speed gradients of the two coupling halves SK_E and SK_A, a shift shock M _{jerk occurs} in the drive train AS. As in 4 is illustrated, is applied to the input-side part SK_E of the clutch SK, a relatively small moment of inertia J _{SK_E} , which essentially results from the drive-side part AS_an of the drive train AS and the electric machine EM. By contrast, a relatively large moment of inertia J _{SK_A} , which _results from the output-side part AS_ab of the drive train AS and the total mass m _{Fzg of} the motor vehicle, is _applied to the output-side part SK_A of the shift clutch SK.

When the clutch SK is _engaged , the rotational speed n _{SK_E} and the rotational speed _gradient dn of the input-side part SK_E are therefore essentially adapted to the rotational speed n _{SK_A} and the rotational speed _gradient dn _{SK_A} / dt of the output-side part SK_A of the clutch SK. Thus, the shift _jerk is given by the equation M _jerk = dω _{SK_E} / dt * J _{SK_E} , which is proportional to the change in the rotational speed ω _{SK_E of} the input side part SK_E of the clutch SK during engagement and proportional to the moment of inertia J _{SK_E} applied _thereto effective forces between the teeth of the two coupling halves SK_E and SK_A is a high force required to engage the clutch SK according to the prior art, and the engagement process itself takes a relatively long time.

In contrast, the synchronization of the target gear with the electric machine EM according to the invention is such that the input-side speed n _{SK_E of} the clutch SK of the target gear with large speed _gradient dn _{SK_E} / dt at the beginning and with a small speed _gradient dn _{SK_E} / dt at the end of the synchronization asymptotically to the _Output speed n _{SK_A of} the clutch SK is adjusted. This is based on the speed _curves n _{SK_E} (t) and n _{SK_A} (t) of the input-side part SK_E and the output-side part SK_A a clutch SK of an automated transmission in 1 for an upshift and in 2 for a downshift illustrated. There, the synchronization of the target gear is in each case at the beginning with a constant drive or drag torque M _{EM of} the electric machine EM until a predetermined _limit speed difference .DELTA.n _{SK_Gr is} reached or fallen _below . In this phase, the constant torque M _{EM of} the electric machine EM leads in each case to a largely constant speed _gradient dn _{SK_E} / dt of the input-side part SK_E of the clutch SK.

After reaching the limit speed _difference Δn _{SK_Gr} at time t1 ', the torque M _{EM of} the electric machine EM is reduced in proportion to the speed difference Δn _SK = n _{SK_A -n SK_E} , so that the amount of the speed _gradient dn _{SK_E} / dt is reduced, respectively, and the speed n _{SK_E of} the input-side part SK_E of the clutch SK asymptotically into the speed n _{SK_A of} the output-side part SK_A passes. Therefore, the clutch SK can be engaged with a small force and without a noticeable shift shock at very low or zero speed difference .DELTA.n _SK .

By a synchronization according to the method of the invention becomes the entire switching operation accelerates, shifting comfort increases and circuit-related load peaks avoided within the drive train AS.

AS

powertrain

AS_ab

output side powertrain

AS_an

Input side powertrain

EM

electric machine

J _{SK_A}

moment of inertia (to SK_A)

J _{SK_E}

moment of inertia (to SK_E)

M _EM

torque (from EM)

M _{EM_max}

maximum permissible Torque (from EM)

m _veh

vehicle mass

M _jerk

shift shock

n

rotation speed

n _{SK_A}

(Output side) Speed (from SK_A)

n _{SK_E}

(Input-side) Speed (from SK_E)

dn _{SK_A} / dt

speed gradient (from SK_A)

dn _{SK_E} / dt

speed gradient (from SK_E)

Δn _SK

Speed difference (to SK)

Δn _{SK_Gr}

Limit speed difference (to SK)

SK

clutch

SK_A

output side Part of SK

SK_E

input side Part of SK

t

Time

t0

time

t1

time

t1 '

time

Δt _Einr

Einrückdauer

Δt _{Einr_Gr}

Grenzeinrückdauer

ω _{SK_E}

rotation speed (from SK_E)

Claims (7)

Method for switching control of an automated gearbox, which is arranged in a drive train of a motor vehicle between an internal combustion engine and a final drive, also provided with unsynchronisierten clutches, and whose input shaft is connected to a motor and generator operable electric machine or connectable, wherein at a circuit between a Load gear and a target gear synchronization of the target gear by means of the electric machine, characterized in that the electric machine (EM) is controlled to synchronize the target gear such that the input-side speed n _{SK_E} the clutch (SK) of the target gear with large speed _gradient dn _{SK_E} / dt At the beginning and with a small speed _gradient dn _{SK_E} / dt at the end of the synchronization is adjusted asymptotically to the output speed n _{SK_A of} the clutch (SK). A method according to claim 1, characterized in that during the synchronization of the target gear, the input-side speed n _{SK_E} and the output-side speed n _{SK_A of} the clutch (SK) are determined that the currently to be synchronized speed difference Δn _SK = n _{SK_A} - n _{SK_E is} calculated , and that the torque M _{EM of} the electric machine (EM) is reduced in proportion to the changing speed difference Δn _{SK of} the clutch SK. A method according to claim 2, characterized in that the electric machine (EM) at a positive speed difference Δn _SK > 0 is operated by a motor, and that the drive torque M _EM > 0 of the electric machine (EM) is reduced in proportion to the speed difference Δn _SK . A method according to claim 2, characterized in that the electric machine (EM) is operated as a generator at a negative speed difference Δn _SK <0, and that the drag torque M _EM <0 of the electric machine (EM) is reduced in proportion to the speed difference Δn _SK . Method according to at least one of claims 1 to 4, characterized in that the synchronization of the target gear at the beginning with a constant drive or drag torque M _{EM of} the electric machine (EM) takes place until a predetermined _limit speed difference .DELTA.n _{SK_Gr is} reached or fallen _below , and that Subsequently, the torque M _{EM of} the electric machine (EM) proportional to the speed difference Δn _{SK is} reduced. A method according to claim 5, characterized in that the constant drive or drag torque M _{EM of} the electric machine (EM) corresponds to a maximum allowable torque M _{EM_max of} the electric machine (EM). Method according to at least one of claims 1 to 6, characterized in that after reaching the synchronous _speed (n _{SK_E} = n _{SK_A} ) the engagement time .DELTA.t _Einr for closing the clutch (SK) is determined, and that when exceeding a predetermined _{Grenzinrückdauer} .DELTA.t _{Einr_Gr} of Input side part SK_E of the clutch (SK) by the electric machine (EM) is acted upon by an angular momentum.