Method for controlling the shifting of an automated dual clutch transmission

Translation of description of equivalent WO 2004058535 A1

Shift control method for an automated dual clutch transmission

The invention relates to a method for switching controlling an automated dual clutch transmission comprising a first partial transmission with a first transmission input shaft, a first engine clutch, and a first group of gears and a second partial transmission with a second transmission input shaft, a second engine clutch, and a second group of gears, with a shift between a low gear and a same partial transmission assigned target gear using a the other partial transmission associated intermediate gear as a multiple shift with the switching steps inserting the intermediate gear, clutch change from the engine clutch of the load transfer to the engine clutch of the intermediate gear, laying out the load profile, engaging the target gear, clutch replacement is performed by the engine clutch of the intermediate gear to the engine clutch of the target gear, and the engine speed of the associated drive motor is led to the end of the shift to the synchronous speed of the target gear.

The design of the dual clutch transmission has long been known, for example from DE 35 46 454 A1, in which a gear transmission for a motor vehicle with a double clutch is proposed. The dual clutch transmission comprises a first engine clutch, a first transmission input shaft, and a first group of gears, which form a first partial transmission, and a second engine clutch, a second transmission input shaft, and a second group of gears that form a second partial transmission. By inserting one of the passages in question, the transmission input shaft with a common transmission output shaft is connected. In the usual alternating assignment of the courses in which the one component transmission the even gears and the other sub-transmission associated with the odd gears, there is a simple sequential shifting from an engaged load gear to a next higher or lower, that is, each of the other partial transmission assigned target gear first, provided that it is a passive closable coupling, in an opening of the gear train of the target gear associated motor coupling, in a selection of the target path, and in a subsequent overcut opening of the partial transmission of the load profile associated with motor coupling and closing of the partial transmission of the target gear assigned Clutch. The power transmission is thus alternately over the first partial transmission with the first engine clutch and the first transmission input shaft and the second partial transmission with the second engine clutch and the second transmission input shaft, a particular advantage when changing gear no Zugbzw. Thrust interrupt occurs, which is why the dual clutch transmission is also associated with the kind of power shift. Since a considerable mechanical effort would be required in case of manual actuation of two engine clutches and shifting the gears with a temporary two simultaneously engaged gears, are dual-clutch transmission, if known, automated design, ie that both the operation of the motor clutches and gear shifting via assigned actuators takes place, the electromagnetic, electric motor, pressure medium, as can be hydraulically actuated or otherwise formed eg.

In certain operating situations, essentially of a sudden change of road gradient, for example, a transition from a horizontally extending into a steep uphill road, and / or the power demand of the driver, for example, a fast depression of the accelerator pedal in order to achieve a rapid acceleration (kick-down ), are dependent, may no longer be sufficient, a simple sequential shift may, to meet the requirements of the engine and transmission control and / or the driver. In this case, a switching operation is required, in which at least one gear is skipped, that is the load gear and the target gear are associated with the same partial transmission. In order to avoid a tensile or shear force interruption even in this case carried out such a switching operation preferably using a part of the other gear assigned to the intermediate gear as so-called multiple shift.

To perform such multi-circuit as quickly as possible, the required speed adjustment, ie, the adjustment of the motor speed to the effective in the associated motor coupling synchronous speed of the target gear, according to the prior art already performed during the switching operation. Here, a SoUDrehzahlgradient is predetermined, after the engine speed is guided by means of the motor controller and / or the overlap control of the motor couplings to the end of the shifting operation to the synchronous speed of the target gear. Equals to actual shift progress, ie the timing of the individual switching steps, and the resulting overall response time in the underlying estimated total shift time, as the engine speed reaches the synchronous speed of the target gear exactly at the desired time. Due to changing operating conditions, in particular different operating temperatures, and wear on the engine clutches and the switching and synchronization elements of the transmission, the part of the switching times of the individual switching steps and thus the total switching time of multiple circuit can not be accurately determined in advance, so that the engine speed synchronous speed not usually accomplished at the desired time. Does the shifting operation, ie the implementation of the individual switching steps, faster than expected, so hastens the shift sequence of the speed adjustment advance, ie at the end of the shift, a waiting time in must be accepted, in which the engine speed still runs through the remaining difference in rotational speed to achieve synchronous speed , Does the shifting process is slower than expected, so the speed adaptation is ahead of the shifting sequence, ie, the engine speed on the prematurely reached synchronous speed of the target gear must remain at the end of the shift until the shift is completed. In the first case enters a real delay of the entire circuit sequence, in the second case only because of the temporarily constant engine speed, the driver of potentially perceived as unpleasant, apparent delay of the circuit sequence is recorded.

It is therefore the problem of the present invention to provide a method for controlling such, above-defined sequence circuit, with which the speed adaptation can be improved and the known defects can be avoided.

The problem is inventively solved in connection with the preamble of claim 1, characterized in that at the beginning of the shift process (t = to), an initial nominal speed gradient (dn_M/ Dt)₀ is predefined, with which the engine speed n at an estimated total shift time .DELTA.t_sΣ the synchronous speed n_Ms at the end of the switching operation ensures that the engine speed n of the drive motor at the start of the switching operation, first according to the predefined initial nominal speed gradient (dn_M/ Dt) o changed, is that determined during the switching operation of the actual shift progress and compared to the estimated shift progress, and that the target speed gradient dn_M/ Dt is adjusted at a determined deviation of the shift progress to the actual shift progress.

Advantageous embodiments of the inventive method are listed in the dependent claims 2 to 12th

The engine speed n_M So is first after the given initial target speed gradient (dn_M/ Dt)₀ controlled or regulated to the synchronous speed n_MS out of the target gear and achieved the desired time for the end of the shift, unless the actual shift progress, ie the timing of the shift or the individual switching steps S1 - S5, the estimated shift progress corresponds. If, however, as a result of changed operating conditions, such as extreme operating temperatures or wear on switching and synchronization elements, so are recognized to delays or accelerations in the shift sequence these deviations by the inventive method and by adjusting the target speed gradient dn_M/ Dt compensated. In a recorded compared to the estimated shift progress faster shift progress the target speed gradient is dn_M/ Dt consequently increased in amount and decreased at a determined slower shift progress in amount. Thus, the effect that the engine speed n_M the synchronous speed n_Ms achieved at the right time at the end of the shift. A prior art standard at a faster shift progress waiting time until the engine speed n_M the synchronous rotational speed has reached ns, is thus avoided. In the opposite case is also a prior art standard for a slower shift progress phase in which the engine speed n_M n on the synchronous speed_Ms must be kept constant largely avoided. The inventive method ensures that the shifting sequence of the above-described multiple circuit runs as fast as possible and as comfortable as possible. The inventive method is preferably used for carrying out a traction downshift, but is also applicable to a traction upshift, downshift at a shear, and at a thrust upshift.

The adjustment of the nominal speed gradient dn_M/ Dt is expediently characterized in that the previously valid target speed gradient dn_M/ Dt by a corrected nominal speed gradient (dn / dt)_kor is replaced with which the engine speed n_M at a estimated remaining shift time Δ the synchronous speed n_MS reaches the end of the shift.

Since a continuous examination of the shift progress and a quasi-continuous adjustment of the nominal speed gradient dn_M/ Dt would be too costly, the determination of the shift progress and, if necessary, adjust the target speed gradient dn is_M/ Dt advantage by the end of each shift step S1 - S4 performed. However, as a correction of the target speed gradient dn_M/ Dt after the last switching step S5 no longer makes sense, the adaptation only until the penultimate switching step S4. Minor variations of the engine speed n_M of the synchronous speed ns at the end of the shift, which may be due to variations of the shifting progress in the last switching step S5, have to be taken into account.

The initial target speed gradient (dn_M/ Dt)₀ n may in a simple manner at the start of the switching operation by detecting the current engine speed_M0 and the synchronous speed of the target gear n_MS and N by forming the quotient of the difference between the synchronous speed_Ms and the initial engine speed n_Mo and a previously known total estimated switching time .DELTA.t_sΣ'((Dn / dt)₀ = (N_Ms - n_Mo) / .DELTA.t_sΣ) are determined. For this purpose, the estimated total switching time .DELTA.t_sΣ'As the sum of the estimated partial shift times .DELTA.t_Sι 'of the individual switching steps S1 - S5 are calculated (At_sΣ'= -Σ Δtsi', i = 1 - 5). The estimated total switching time .DELTA.t_sΣ'And / or the estimated partial shift times .DELTA.t_s. ' be expedient previously, ie determined during the development of its dual-clutch transmission or the motor vehicle, in test bed and / or driving tests and stored in a transmission data storage from which they can be read as needed.

Similarly, the corrected target speed gradient (dn_M/ Dt)_kor n from a simple manner by a detection of the current engine speed_M and n by a quotient of the difference between the synchronous speed_Ms and the instantaneous engine speed n and a previously known estimated remaining shift time Δ-SR '((dn_M/ Dt)₀ = (N_Ms - ΓIM) / Δ._SR ') can be determined. For this purpose, in the discontinuous procedure, that an adjustment of the nominal speed gradient dn_M/ Dt at the end of each shift step S1 - S4, the estimated remaining shifting time Δ._SR 'as a sum of estimated partial shift times Δtsi 'of the individual, outstanding shifting steps SI + 1 - are calculated S5 (Δ = Σ Δtsi', i = l + 1 - 5).

By running-in process, and wear on switching and synchronization elements in the dual clutch transmission, it may in the course of operation or life to permanent shifts of part switching times .DELTA.t_Sι and thus the residual switching times .DELTA.t_SR and the total switching time .DELTA.t_sΣ come. To avoid large corrections of the target speed gradient d_nM/ Dt, especially during the first switching steps, it the stored values ​​of the estimated total shift time is therefore sensible .DELTA.t_sΣ'And / or of the estimated remaining shift times Δ and / or the estimated partial shift times .DELTA.ts_,'In case of deviations of the switching progress .DELTA.t by the values ​​of the actual switching times_sΣ or .DELTA.t_SR or .DELTA.ts. to correct. One such adaptive correction can in the simplest case be achieved in that the stored values ​​of the estimated shift times .DELTA.W or Δ._SR'Or .DELTA.ts_,'By the values ​​of the actual switching times .DELTA.t or ΔtsΣ_SR or Δtsi be replaced. In order to eliminate outliers, it is better if the stored values ​​of the estimated response times .DELTA.W 'or Δ or Δ means of a correction function with the values ​​of the actual switching times .DELTA.t_sΣ or .DELTA.t_SR or Δtsi are corrected.

Since the clutch change from the engine clutch of the intermediate gear n to the engine clutch of the target gear at a constant engine speed_M is easier and faster controlled, the initial target speed gradient (dn_M/ Dt)₀ and the corrected target speed gradient (dn_M/ Dt)_kor suitably determined such that the engine speed n_M the synchronous speed n_Ms reached the end of the penultimate switching step S4. That the purposes of the foregoing description of the method of switching penultimate step S4 is regarded as the last switching step and the end of the penultimate switching step S4 as the end of the shift.

Further details of the invention will become apparent from the following detailed description and the accompanying drawings which are given by way of example for explaining the control method of the invention.

For this show: FIG. 1 the engine speed characteristic according to the invention at a controlled

Circuit operation in the form of a time chart, and

Fig. 2 shows the engine speed at a controlled course in accordance with the prior art circuit operation in the form of a timing diagram.

In FIG. 2, the time sequence is shown a pulling downshift of the dual clutch transmission, which is performed as a multiple shift of the type defined and proceeds according to the prior art. FIG. 2, refer to the profile of the engine speed n of an associated drive motor over time t during the switching operation, which comprises a total of five shift steps. In the first switching step S1, the intermediate gear is engaged, the second shifting step S2, the clutch change from the engine clutch of the load transfer to the engine clutch of the intermediate gear is effected, in the third switching step S3 the load gear is disengaged, the fourth shifting step S4, the target gear is engaged, and the fifth shifting step S5 carried out the clutch change from the engine clutch of the intermediate gear to the engine clutch of the target gear. Since the last change of clutch can be controlled at a constant engine speed quicker and easier, it is provided that the engine speed n_M the synchronous speed n_MS the target gear already reached the end of the penultimate switching step S4. The last clutch change can then at nearly constant engine speed, namely the synchronous speed n_MS, Done.

The shift begins at time t₀ and is expected to end at the time t₅, This requires, however, that the individual switching steps S1 - S5 run time as intended, ie S1 between t₀ and) with the estimated time .DELTA.W, S2 between ti and t₂ runs with the estimated length of time ΔW'- etc., and thus the entire shifting operation in the time period provided .DELTA.W. The envisaged total switching time .DELTA.W that from the sum of the planned partial switching times .DELTA.t-si, i = 1-5 result is, that in addition to the speed difference between the synchronous speed n_Ms and the engine speed at the start of the switching process no the basis for determining a target speed gradient dn_M/ Dt, after the engine speed n_M is guided to the synchronous speed ns during the switching operation. Due to the foregoing, the speed adjustment is made during the switching steps S1 to S4, ie in the sense of the process of switching penultimate step S4 is to be regarded as the last switching step (.DELTA.W = ΣΔt_Sι ', i = 1 - 4). Corresponds to the shift progress, ie the actual amount of time .DELTA.t_Sι the individual switching steps S1 to S4 or the actual total shift time .DELTA.W. the anticipated shift progress, ie .DELTA.t_Sι = .DELTA.t_Sι 'or .DELTA.W = .DELTA.W so reaches the engine speed n_M with the target speed gradient dn / dt exactly at the desired time, namely the end of switching step S4, the synchronous speed n_Ms of the target gear (ts = t₄). The corresponding speed curve represented by curve 1 (solid line). However, this ideal situation is seldom correspond to reality. Due to changing operating conditions, such as different operating temperatures and wear on switching and synchronization of the respective gear elements, it is, in practice, deviations of the time sequence of the switching operation.

The present case, for example, two such cases illustrated. In case A, the entire Schaitvorgang runs faster than expected, because the actual length of time .DELTA.t_S2 the second shifting step S2 shorter than expected (.DELTA.t_S2 <.DELTA.t_S2'). Consequently, the fourth shifting step S4 is already at time t_4A terminated, whereas the engine speed n_M corresponding to curve 2 (= curve 1) the synchronous speed ns is achieved only at the time. So there arises a waiting time .DELTA.t_WA- In the further circuit flow n to achieving the synchronous speed_Ms have to wait. The ideal speed progression (desired) would play in this case by curve 2 '(dashed line). In case B, the entire switching operation is running slower than expected, because the actual length of time .DELTA.t_S2 the second shifting step S2 longer than expected (.DELTA.t_S2 > .DELTA.W ') - Consequently, the fourth shifting step S4 is only at the time t_4B terminated, whereas the engine speed n_M corresponding to curve 3, the synchronous speed n_Ms already reached at the time. The engine speed n_M must be held in this case roughly constant at the synchronous speed ns until the fourth shifting step S4 is completed. It arises because although no real delay of the circuit sequence, however, due to the temporarily constant engine speed by a driver perceived, apparent waiting time .DELTA.t_WB- The ideal speed progression (desired) would play in this case by curve 3 '(dash-dotted line).

In contrast, the same switching process is according to the inventive method as shown in Fig. 1 from FIG. First, an initial target speed gradient is (dn_M/ Dt)₀ predefined, with which the engine speed n_M in compliance with the estimated Total switching time .DELTA.t_sΣ'The synchronous speed n_Ms the end of the shift, ie in this case, reached exactly at the end of the fourth shifting step S4 (see graph 1, 1a / solid line). After this initial target speed gradient (dn / dt)₀, Which as indicated as the quotient of the difference between the synchronous speed n_MS and the initial engine speed no and a previously known estimated total shift time .DELTA.W can be calculated ((dn_M/ Dt)₀ = (N_Ms - n_Mo) / Δ) ,. is the engine speed n_M changing the drive motor at the start of the shift. After the end of each scarf kick S1 - S3, the actual shift progress is determined and compared with the estimated shift progress. In a determined deviation of the switching progress of the estimated shift progress, ie a substantial deviation of the actual partial shifting time Δtsi of the estimated partial shifting time Δtsi 'the just-ended switching step is, the target speed gradient dn_M/ Dt, the initially identical to the initial target speed gradient (dn_M/ Dt)₀ is adapted to the actual shift progress. This is expediently characterized in that the previously valid target speed gradient dn_M/ Dt by a corrected nominal speed gradient (dn_M/ Dt)_kor is replaced with which the engine speed n_M in compliance with an estimated remaining shift time .DELTA.W the synchronous speed n_MS reaches the end of the shift.

Are present to illustrate the method according to the invention in Fig. 1 by way of example the same two cases as shown previously in Fig. 2 for the prior art. In case A, the entire switching operation runs faster than expected, because the actual length of time .DELTA.t_S2 the second shifting step S2 shorter than expected (.DELTA.W <.DELTA.W ') - This deviation is however now been found after the completion of the second shifting step S2 at the time. Thereupon, the previously valid SoUDrehzahlgradient, after the engine speed has been changed, by a corrected target speed gradient (dn_M/ Dt)_kor replaced with which the engine speed n_M 2a corresponding to curve (dashed line) the synchronous speed n_Ms exactly at the desired time t_4A reached at which the switching operation (without the fifth switching step S5) is terminated prematurely. The corrected target speed gradient (dn_M/ Dt)_kor is in the amount larger and, as stated, as a ratio of the difference between the synchronous speed ΠM_S and the instantaneous engine speed n_M2A and a previously known estimated remaining shifting time .DELTA.W be calculated ((dn_M/ Dt)_kor = (N_Ms - Π_M2A) / .DELTA.t_S ), Where the estimated remaining shifting time .DELTA.W present the sum of the estimated partial shift times of switching steps S3 and S4 results (.DELTA.W = .DELTA.W ' ⁺ Δ ') ■ A common prior art waiting time .DELTA.t_WA (See FIG. 2), n in the further circuit flow to the achievement of the synchronous speed_Ms must wait is now avoided. The actual speed progression for case A arises from the juxtaposition of the partial curves 1a, 2a, and 2. FIG.

In case B, the entire switching operation is running slower than expected, because the actual length of time .DELTA.t_S2 the second shifting step S2 longer than expected (.DELTA.t_S2 > .DELTA.W). The deviation that occurs will turn after the completion of the second shifting step S2 at time t_{2 B} detected. Then, the previously valid target speed gradient is a corrected target speed gradient (dn_M/ Dt)_k0r replaced with which the engine speed n_M corresponding to curve 3a (dot-dashed line) the synchronous speed n_MS exactly at the desired time 1_4B reached at which the switching operation (without the fifth switching step S5) is completed late. The corrected target speed gradient (dn_M/ Dt)_kor is reduced in amount, and may, as before n as the quotient of the difference between the synchronous speed_Ms and the instantaneous engine speed n _B and the previously known estimated remaining shifting time .DELTA.W be calculated ((dn dt)_kor = (N_Ms - n_M2SS) / W). A common prior art apparent waiting time .DELTA.t_A (See FIG. 2) in which the engine speed n_Ms largely must be kept constant to await the end of the shift or the conclusion of the fourth shifting step S4, will now also be avoided. The actual speed curve obtained now by the juxtaposition of the Teilkurveϊi 1a, 3a, and 3. FIG.

By applying the control method of the invention, the verification of the switching progress and, if necessary, adjustment or correction of the target speed gradient dn_M/ Dt at least after each switching step provides can thus be achieved with a dual-clutch transmission in a multiple circuit of the type defined the switching process itself, ie the engagement and disengagement of the participating courses and the first clutch change, and the concurrent speed adaptation terminated substantially simultaneously will. LIST OF REFERENCE NUMBERS

n_M Engine speed n_M0 n_M at the start of the switching operation

ΠM2A n_M the end of switching step S2 in the case of A

ΠM2B n_M the end of switching step S2 in the case B

ΠMS synchronous speed

51 first switching step

52 second switching step

53 third switching step

54 fourth switching step

55 fifth switching step

Sl ith switching step, current switching step

SI + 1 (i + 1) th switching step, next step switching time t t₀ t the beginning of the shift t | t the end of S1 (estimated) t₂ t the end of S2 (estimated) t the end of S2 (is case A) t_{2 B} t the end of S2 (is case B) t₃ t the end of S3 (estimated) t the end of S3 (is case A) t_3B t the end of S3 (is case B) t the end of S4 (estimated) ti_A t the end of S4 (is case A) tn₃ t the end of S4 (is case B) t₅ t the end of S5 (estimated) t_s t to the n_Ms is achieved

Δtsi period of S1 (is)

Δtsi 'period of S1 (estimated)

.DELTA.t_S2 Period of S2 (is)

.DELTA.t_S2'Period of S2 (estimated)

.DELTA.t_S3 Period of S3 (is) .DELTA.W 'Period of S3 (estimated)

.DELTA.t_S4 Period of S4 (is)

.DELTA.W 'Period of S4 (estimated)

.DELTA.W 'Period of S5 (estimated)

.DELTA.t_Sι time period of the i-th switching stage (IST)

.DELTA.t_Si 'period of the i-th switching step (estimated)

.DELTA.t_SR Duration of the remaining switching steps, residual switching time (is)

.DELTA.t_SR time the remaining switching steps, residual switching time (estimated)

.DELTA.W Time all switching steps, total switching time (is)

.DELTA.W Time all switching steps, total switching time (estimated)

ΔtwA waiting time in case A

ΔtwB (apparent) waiting time in case B dn_M/ Dt target speed gradient

(dn_M/ Dt)₀ Initial target speed gradient

(dn_M/ Dt)_kor corrected desired speed gradient