DE102007005396A1 - Motor vehicle automatic gearbox i.e. variable automatic gearbox, operating method, involves controlling switching unit such that friction moment lies against unit during starting of lifting of moments and is released at synchronous point - Google Patents

Abstract

The method involves reducing a friction moment before obtaining a synchronous point of a traction uplift to be implemented. The friction moment is increased at a region of the synchronous point, and a switching unit to be switched off is controlled in such a manner that the friction moment lies against the switching unit during starting of lifting of engine moments and before obtaining the synchronous point of the traction uplift to be implemented. The friction moment is released at the region of the synchronous point.

Description

The The invention relates to a method for operating an automatic transmission according to the preamble of claim 1.

vehicles need Gearbox to convert torques and speeds. Task of a transmission is to implement the traction power supply of a drive unit. The present invention relates to a method of operation an automatic transmission. Within the meaning of the present invention Under the term automatic transmissions are meant all transmissions with a automatic gear change to be understood, which also referred to as a stepped automatic transmission become.

at Automatic transmissions, the circuit sequence and thus the circuit quality by various factors are determined, e.g. B. by the activation of a for execution a circuit to be switched off switching element, by the control one for execution the circuit zuzuschaltenden switching element, by the during the circuit at the transmission input applied engine torque, through the constructive execution the switching elements and lubricants used. Most These factors are due to the construction of the automatic transmission set, allowing to influence the circuit quality, which is determined by determines the transmission output torque applied to the transmission output is, only the control of the off and zuzuschaltenden Switching element and the voltage applied to the transmission input engine torque be available.

automatic transmission have the Peculiarity that the transmission output torque that significantly influences the circuit quality also by internal gear inertia, which in execution of a Circuit must be braked or accelerated, is affected.

Especially in the execution sportive traction shifts with a relatively steep engine speed gradient affect the internal mass inertia of an automatic transmission the gear output torque applied to the transmission output in terms of on a transmission output torque increase so strong, that the circuit quality is felt by a driver as unacceptable. It exists therefore, a need for a method of operating an automatic transmission, with which the circuit quality negatively affecting transmission output torque peaks, especially at sportive train upshifts with a relative steep engine speed gradient, can be reduced.

• a) zur Verringerung einer die Schaltungsqualität beeinträchtigenden Getriebeausgangsmomentüberhöhung zu Beginn der auszuführenden Zughochschaltung wird die Motormomentreduzierung kontinuierlich durchgeführt oder bei einer stufenartigen Motormomentreduzierung wird das abschaltende Schaltelement derart angesteuert, dass an demselben bis zur stufenartigen Motormomentreduzierung ein Reibmoment anliegt;
• b) zur Verringerung einer die Schaltungsqualität beeinträchtigenden Getriebeausgangsmomentüberhöhung zum Ende der auszuführenden Zughochschaltung wird das zuschaltende Schaltelement derart angesteuert, dass vor Erreichen eines Synchronpunkts der auszuführenden Zughochschaltung ein an demselben anliegendes Reibmoment reduziert und im Bereich des Synchronpunkts dasselbe wieder erhöht wird, und/oder das abschaltende Schaltelement wird derart angesteuert, dass vor Erreichen eines Synchronpunkts der auszuführenden Zughochschaltung an demselben ein Reibmoment anliegt und im Bereich des Synchronpunkts dasselbe wieder entfernt wird.

On this basis, the present invention based on the problem to provide a novel method for operating an automatic transmission. This problem is solved by a method according to claim 1. According to the invention, the method comprises at least the following steps:

• a) to reduce a circuit quality impairing transmission output torque increase at the beginning of the train upshift to be performed the engine torque reduction is performed continuously or in a step-like engine torque reduction the shutdown switching element is driven such that at the same applied to the step-like engine torque reduction a friction torque;
• b) to reduce the circuit quality impairing transmission output torque increase to the end of the train upshift to be executed the switching switching element is controlled such that before reaching a synchronization point of the executed upshifting a friction torque applied to the same and in the region of the synchronization point the same is increased again, and / or the abschaltende Switching element is controlled such that before reaching a synchronous point of the train upshift to be executed at the same applies a friction torque and the same is removed again in the region of the synchronization point.

With the method according to the invention can at the beginning of a to be performed Up-shift and at the end of the up-train to be executed the circuit quality impairing transmission output torque increases are reduced whereby the circuit quality, especially in sporty train upshifts with a steep Engine speed gradient, is significantly improved.

preferred Further developments of the invention will become apparent from the dependent claims and the following description. Embodiments of the invention without being limited to this to be closer to the drawing explained.

there shows:

1a a diagram illustrating a known from the prior art method for operating an automatic transmission of a motor vehicle;

1b a diagram for clarification of the execution of the method according to 1a adjusting transmission output torque;

2a a diagram for illustrating the method according to the invention for operating an automatic transmission of a motor vehicle according to a first embodiment of the invention;

2 B a diagram for clarification of the execution of the method according to 2a adjusting transmission output torque;

3a a diagram illustrating the inventive method for operating an automatic transmission of a motor vehicle according to a second embodiment of the invention;

3b a diagram for clarification of the execution of the method according to 3a adjusting transmission output torque;

4a a diagram illustrating the inventive method for operating an automatic transmission of a motor vehicle according to a third embodiment of the invention;

4b a diagram for clarification of the execution of the method according to 4a adjusting transmission output torque;

5a a diagram illustrating the inventive method for operating an automatic transmission of a motor vehicle according to a fourth embodiment of the invention;

5b a diagram for clarification of the execution of the method according to 5a adjusting transmission output torque;

5c a diagram for clarification of the execution of the method according to 5a adjusting clutch differential speed;

6a a diagram illustrating the inventive method for operating an automatic transmission of a motor vehicle according to a fifth embodiment of the invention;

6b a diagram for clarification of the execution of the method according to 6a adjusting transmission output torque and

6c a diagram for clarification of the execution of the method according to 6a adjusting clutch differential speed.

Before referring to 2a to 6c the method according to the invention for operating an automatic transmission will be described in detail, with reference to 1a and 1b be received on a known from the prior art method for operating an automatic transmission.

So shows 1a a diagram in which a plurality of temporal signal waveforms are entered for a pull upshift, wherein a temporal waveform 1 the time course of an engine speed during the pull upshift to be executed, a time waveform 2 the time course of an engine torque during the pull upshift to be executed, a time waveform 3 the temporal course of a friction torque at a switch-off during the upshifting circuit to be executed switching element and a time waveform 4 shows the temporal waveform of a friction torque at a zuzuschührenden during the upshift circuit switching element. According to the signal curves 3 and 4 In the case of the upshifting circuit to be executed, the switching element to be disconnected and the switching element to be connected are simultaneously active, for which reason the upshift circuit is designed as a so-called overlapping circuit.

1a can be seen that it is already known from the prior art, to perform a pull upshift according to the temporal waveform 2 to reduce the engine torque for a defined period of time, according to the waveform 2 the engine torque is abruptly reduced to a circuit start and in turn is increased to a circuit end, in particular ramp-shaped and thus continuously.

When carrying out a pull upshift with a control of the engine torque according to the waveform 2 , the switching off switching element according to the waveform 3 and the switching element switching according to the waveform 4 turns on at the transmission output in 1b through the temporal signal course 5 visualized transmission output torque, wherein both at the beginning of the train upshift to be executed (see circle 6 in 1b ) as well as the end of the upshift (see circle 7 in 1b ) forms a significant transmission output torque increase.

such Affect transmission output torque increases the shift quality and fall in a sporty Zughochschaltungen with a steep or high gradient of the engine speed particularly strong.

The The present invention relates to a method with the aid of at the beginning of the circuit and the circuit end such Impairing shift quality Gearbox output torque increases reduced can be.

2a and 2 B illustrate a first embodiment of the method according to the invention, wherein in 2a and 2 B temporal signal Gradients are shown for the same sizes as 1a and 1b Therefore, to ensure a simpler representation of the invention for the corresponding waveforms same reference numerals are used.

According to the embodiment of the 2a is to reduce a shift quality affecting transmission output torque increase at the beginning of the to be executed Zughochschaltung in the beginning of the circuit (see circle 6 in 2a ) according to the waveform 2 the motor torque reduction already started during the rise of the friction torque in the engaging clutch and not abruptly, but rather continuously carried out.

According to 2a becomes the engine torque (see signal curve 2 ) between times 8th and 9 continuously reduced from a non-reduced value to a reduced value in the form of a linear ramp. By this early and continuous reduction of the engine torque and the transmission input torque at the beginning of the train upshift to be executed can according to the waveform 5 the transmission output torque increase over the prior art at the beginning of the circuit (see circle 6 ) are significantly reduced.

In order to reduce at the end of the train upshift to be executed a circuit quality impairing transmission output torque increase, in the embodiment of the 2a to the end of the circuit (see circle 7 in 2a ) according to the waveform 4 the switching element to be switched on during the upshift circuit to be executed in such a way that, before reaching a synchronization point 10 the upshift circuit to be executed reduces the friction torque of the switching element to be connected and in the region of the synchronization point 10 subsequently increased again. The reduction and subsequent increase in the frictional torque of the switching element to be connected during the upward pull-up operation takes place in accordance with FIG 2a each ramp-shaped and thus continuous.

In the illustrated embodiment of the 2a becomes the sync point 10 the synchronizing circuit to be executed is achieved during the continuous reduction of the friction torque of the switching element to be connected. The subsequent increase in the reduction of the frictional torque thereof accordingly takes place according to 2a after reaching the synchronization point 10 , In contrast to this, it is also possible that before the synchronization point is reached or when the synchronization point is reached, the increase of the friction torque subsequent thereto is carried out.

With the above reduction and subsequent increase in the frictional torque of the switching element to be connected during execution, the circuit end (see circle 7 in 2 B ) the transmission output torque increase over the prior art can be significantly reduced.

3a and 3b show an alternative embodiment of the method according to the invention which concerns the start of the circuit of the train upshift to be executed, wherein according to the signal curve 2 of the 3a a jump-shaped or step-like and thus discontinuous engine torque reduction at the beginning of the upshift circuit to be executed (see circle 6 in 3a ) is carried out.

According to the waveform 3 however, the switching element which shuts down during the upshift circuit to be executed is actuated in such a way that a friction torque is applied to the shunting switching element until the stepwise motor torque reduction. According to 3a is at the time 11 , in which the engine torque (see waveform 2 ) is reduced stepwise or stepped, at the disconnecting switching element has a braking effect and thus deviating from zero, negative friction torque (see waveform 3 ) at. This can lead to the beginning of the circuit (see circle 6 in 3b ) over the prior art, the transmission output torque increase can be significantly reduced.

A further embodiment of the method according to the invention 4a and 4b , where the in 4a and 4b variant shown concerns the reduction of the transmission output torque increase to the end of the to be executed upshift. In the embodiment according to 4a and 4b At the end of the circuit, the switching element which switches off during the execution of the upshift circuit is activated in such a way that, before reaching the synchronization point 10 the pull upshift is applied to the same a friction torque, wherein the friction torque in the region of the synchronization point is removed again. According to the waveform 3 in 4a In this case, the switching off switching element is driven such that with the beginning of the increase of the engine torque and before reaching the synchronization point 10 the train upshift to be executed at the same the friction torque is continuously increased, then kept approximately constant and subsequently continuously reduced again, so that then applied to the switching-off switching element no friction torque. The removal of the friction torque from the switching off switching element is preferably carried out before or with reaching the synchronization point 10 However, the same can be continuously reduced even after reaching the synchronization point. Also by this measure me can according to the waveform 5 in 4b At the end of the circuit, the transmission output torque increase compared to the prior art can be significantly reduced.

With regard to the variant of 4a and 4b which concern the reduction of the transmission output torque increase at the end of the upshift to be executed, it should be noted that this alternative also in combination with the in 2a and 2 B shown measure to reduce the transmission output torque increase can be used for the circuit end.

Then, if so 2a shows, in order to reduce the transmission output torque increase to the end of the train upshift to be executed, the switching element is activated in such a way that before reaching the synchronization point 10 the train upshift to be executed reduces the friction torque applied thereto and is increased again in the region of the synchronization point, signal curves may possibly occur in accordance with FIG 5a to 5c form.

5a to 5c in this case relate to the case that at the switching element switching during the circuit end, the friction torque drops too much, so that it is too low to reduce a differential speed in the switching element or to keep at a constant value.

So can 5c , as a temporal waveform 12 shows a time course of the differential speed of the switching element to be switched, it can be seen that due to the reduction of the friction torque of the engaging clutch, the differential speed increases again. In the subsequent increase of the friction torque on the switching element switching this leads to a rapid and shock-like reduction of the differential speed in the switching element, wherein such a jerky degradation is referred to as "flare bump" and adversely affects the circuit quality.

To counteract this jerky reduction of the differential speed in the switching element switching, is in accordance with 6a to 6c proposed, the switching element switching to the circuit end (see waveform 4 in circle 7 in 6a ) to control such that after the reduction of the friction torque, the same is continuously increased in two phases, wherein between the two phases, the friction torque is kept approximately constant.

In a first phase, the friction torque applied thereto is initially increased only to a level at which the differential rotational speed in the switching element (see signal curve) by appropriate control of the switching element 12 in 6c ) is degraded relatively slowly. Only after reaching the synchronization point 10 then the friction torque is increased further starting from this level. As a result, a gentle reduction of the differential speed can be realized in the switching element and the formation of a shift quality negative impact impact can be prevented.

Then, when in the above context of switching elements is mentioned acts these are preferably clutches or brakes of the Automatic transmission.

1

time waveform

2

time waveform

3

time waveform

4

time waveform

5

time waveform

6

circuit beginning

7

circuit end

8th

time

9

time

10

synchronization point

11

time

12

time waveform

Claims (9)

Method for operating an automatic transmission of a motor vehicle, in particular a stepped automatic transmission, wherein a shutdown switching element, in particular a clutch, opened and a zuschaltendes switching element, in particular a further clutch is closed to execute a Zughochschaltung with a particular relatively steep engine speed gradient, and wherein during the current Towing a motor torque reduction is carried out, characterized in that: a) to reduce the circuit quality impairing Getriebeausgangsmomentüberhöhung at the beginning of the train to be executed the engine torque reduction is carried out continuously or at a step-like engine torque reduction the shutdown switching element is driven such that at the same up to the step-like engine torque reduction Friction torque applied; b) to reduce the circuit quality impairing transmission output torque increase to the end of the executed upshift the switching element is controlled such that before reaching a synchronization point of the executed upshifting a friction torque applied to the same and in the region of the synchronization point the same is increased again, and / or the abschaltende switching element is controlled such that with the beginning of the increase of the engine torque and before reaching a synchronization point of the train upshift to be executed at the same applies a friction torque and in the region of the synchronization point the same is removed again. Method according to claim 1, characterized in that in step a), to reduce the quality of the circuit impairing Transmission output torque increase too Start of the to be carried out Zughochschaltung the motor torque reduction is performed ramped. Method according to claim 1, characterized in that in step a), to reduce the quality of the circuit impairing Transmission output torque increase too Start of the to be carried out Upshift in a step-like engine torque reduction the switching off switching element is driven in such a way that on the same until the step-like engine torque reduction a braking acting friction torque is applied. Method according to one or more of claims 1 to 3, characterized in that in step b) for reducing a the circuit quality debilitating Transmission output torque increase to End of the to be carried out Zughochschaltung the switching switching element so controlled is that before reaching the synchronization point of the executed Continuous upshift continuously reduced on the same applied friction torque will, and that before reaching or reaching or after reaching of the synchronization point, the friction torque is increased again. Method according to claim 4, characterized in that that the switching element is activated in such a way that the sync point during the continuous reduction of the friction torque is achieved. Method according to claim 4 or 5, characterized that the switching element is activated in such a way that the friction torque is continuously increased after reducing it. Method according to Claim 6, characterized that the switching element is activated in such a way that the friction torque is continuously increased after reducing it in two phases, wherein the friction torque is approximately constant between the two phases is held. Method according to one or more of claims 1 to 7, characterized in that in step b) for reducing a the circuit quality debilitating Transmission output torque increase to End of the to be carried out Zughochschaltung the switching off switching element driven in such a way that will start with raising the engine torque and before reaching the synchronization point of the executed one Upshifting is continuously increased at the same friction moment, subsequently held approximately constant and subsequently reduced continuously so that before reaching or reaching or after reaching the Synchronous point the friction torque is removed again. Method according to one or more of claims 1 to 8, characterized in that in step b) both the switching Switching element and the switching off switching element is driven.