Method for controlling a gear shifting process in a vehicle with a dual-clutch transmission

Abstract

Method for controlling a shifting process of a vehicle with a dual-clutch transmission, wherein the method comprises the following process steps: deciding on the start of a shift (S100), which determines whether a kickdown shift, where, according to the driver's intention to accelerate, the shifting to a lower gear is carried out based on the operation of an accelerator pedal, whether it has started or not; the decision regarding an odd shift (S200), in which it decides whether the shifting via a different shaft, in which a target gear and a current gear differs from each other by one or more odd gear steps, if the kickdown shift has been initiated, has occurred or not; the control of a clutch torque (S300) in which, if a current switching state of a vehicle, which it decided on in the process step for deciding on a switching via a different shaft, is determined to be the switching via a different shaft, then a torque of a release-side clutch is constantly reduced, while a torque of an engagement-side clutch is increased so constantly that a speed of an input shaft of the target gear and an increasing engine speed are synchronized with each other; Deciding on clutch synchronization (S400), in which it decides whether the speed of an input shaft of the target gear and the engine speed have been synchronized with each other by controlling a clutch torque; and the execution of a switching operation (S500) in which, when the speeds of the input shaft of the target gear and the motor have been synchronized, the switching control is then carried out to engage the gears of the target gear, wherein the procedure step for deciding on clutch synchronization (S400) includes a sub-step (S410) for deciding whether the speed of the input shaft of the target gear and the motor speed have reached a time point for deciding on synchronization (f1) in which the two speeds are equal or similar to each other.

Description

Field of invention

[0001] The present invention relates to a method for controlling a shifting process of a vehicle, in particular a method for controlling a shifting process of a vehicle with a dual-clutch transmission by means of which a driver's intention to accelerate can be quickly reflected in this vehicle with a dual-clutch transmission. State of the art

[0002] The dual-clutch transmission is designed such that two input shafts, each equipped with two clutches to maintain the drive force in stages, and two output shafts corresponding to the respective input shafts, together with a separate shifting mechanism, alternately form a gear according to a range of gear ratios. That is, the drive force is transmitted to one of the two input shafts, with the input and output shafts producing odd and even gears, respectively.

[0003] One of the biggest advantages of a dual-clutch transmission is that it allows for rapid gear changes without interrupting power delivery. For example, when shifting from first to second gear, one clutch connected to an input shaft coupled to the current gear of first gear is disengaged, and immediately afterwards another clutch connected to a different input shaft coupled to a gear of the next gear, second gear, is engaged. This is why rapid gear changes without interrupting power delivery are possible.

[0004] To achieve the rapid, seamless shifting – the greatest advantage of the dual-clutch transmission – it is crucial that the gears of the target gear mesh perfectly during the shift. This is particularly important during downshifting, which reflects a driver's intention to accelerate (referred to below as "kickdown"). Precise shift control is required at the beginning of the shift to ensure that the driver's acceleration is quickly reflected and that any perceived interruption due to a gear ratio difference during the transition is eliminated.

[0005] This is achieved through a motor control of a release clutch at the beginning of the shift. Motor control of a release clutch refers to a control system in which the clutch torque is increased or decreased so that the engine speed (rpm: revolutions per minute) can be matched to the synchronization speed of the gears in a target gear. A release clutch is designed both as a clutch that transmits a driving force from the engine to the currently meshing gears and as the release clutch, which disengages the clutch.

[0006] When a kickdown is performed in the dual-clutch transmission, the torque of the release-side clutch is reduced, thus releasing a power-transmitting connection between the engine and the gears of the current gear, whereas the torque of an engaged clutch (hereinafter referred to as the 'engagement-side clutch') is increased, thus connecting the engine and the gears of the target gear, so that the engine's power is transmitted via the engagement-side clutch to the input shaft connected to it, and then to the gears of the target gear.

[0007] In a conventional automatic transmission, torque transmission is designed so that the "engine control of the release clutch" disengages and simultaneously applies the applied torque to the clutch on the engagement side. In contrast, a dual-clutch transmission requires that the gears of the target gear mesh precisely to transmit the applied torque to the clutch on the engagement side.

[0008] If the gears of the target gear do not yet engage despite the clutch release motor having ceased, then the clutch release motor must continue to engage until the gears of the target gear can. This is why the driver can perceive a sensation of interrupted torque or a lack of acceleration. In other words, only when the clutch release motor and the engagement of the target gear's gears are precisely synchronized can a quick, seamless shift be achieved.

[0009] For the rapid engagement of the gears in the target gear, a control method could be considered in which a hydraulically controlled solenoid valve is activated by applying an overcurrent. However, due to the overcurrent supply, there is a risk of loud noises and vibrations occurring in the vehicle. These vibrations could cause the input shaft to shake, thus preventing frictionless torque transmission via the clutch and consequently significantly impairing shift quality.

[0010] Especially during kickdown shifting, where the difference between the synchronization speed of the target gear and the speed of the input shaft of the current target gear is large, the engine speed is increased even faster, even if the gears mesh as quickly as possible. This necessitates unnecessary 'engine control of the release clutch' or 'engine torque reduction control', etc., which consequently leads to the driver only perceiving the feeling that the torque is not being transmitted correctly, regardless of their acceleration intentions.

[0011] Furthermore, the longer the slippage time between the release clutch and the engine becomes due to the "engine control of the release clutch," the more detrimental this can be to the clutch's lifespan due to wear or heat deformation. Therefore, the engine speed had to be increased slowly during kickdown, taking into account the time it took for the gears of the target gear to engage. This resulted in a shift delay and a lack of satisfactory acceleration.

[0012] Known dual-clutch transmissions are disclosed in DE 10 2014 103 672 A1, DE 10 2015 1134 572 and KR 10 2015 0 125 756 A. Disclosure of the invention; Task of the invention

[0013] The technical problem to be solved according to the invention is to provide a method for controlling a shifting process of a vehicle with a dual-clutch transmission, by means of which the feeling of a torque interruption occurring during kickdown shifting and the wear of the clutch due to a shift delay can be minimized. Solution to the problem of the invention

[0014] This problem is solved according to the invention by a method according to claim 1. Preferred embodiments are set forth in the dependent claims. Favorable effects of the invention

[0015] By means of the method for controlling a shifting process of a vehicle with a dual-clutch transmission according to the present invention, it can be advantageously provided that a clutch torque is controlled such that, during kickdown shifting, the speeds of an input shaft of a target gear and of an engine increase simultaneously, and that an engagement of the gears of the target gear is attempted at the time when the speed of the input shaft of the target gear has been synchronized with the speed of the engine, so that an engine speed increases rapidly in accordance with an acceleration request of the driver, which can consequently lead to the realization of a fast shift without a feeling of torque interruption.

[0016] This means that the torque of an engagement-side clutch is controlled in such a way that the increase in the rotational speed of an input shaft, to which the gears of the target gear are coupled, and the increase in engine speed occur simultaneously before the engagement of the gears of the target gear, so that a shift delay that occurs during kickdown shifting, where the difference between the speed of the input shaft of the target gear and the engine speed is large, can be improved, and thus the feeling of a torque interruption and clutch wear due to the shift delay can be minimized. Brief description of the drawings

[0017] They show: Fig. 1 a diagram illustrating a method for controlling a shifting process of a vehicle with a dual-clutch transmission according to the state of the art; Fig. 2 a schematic diagram of a dual-clutch transmission relating to the present invention; Fig. 3 a flowchart illustrating a method for controlling a shifting process according to an embodiment of the present invention, which is used to control a shifting process of a vehicle with a dual-clutch transmission; Fig. 4 a diagram illustrating a method for controlling a shifting process of a vehicle with a dual-clutch transmission according to the present invention; and Fig. 5 A diagram comparing the states of the shift delay before and after the improvement of a control of a shifting process of the dual clutch transmission. Preferred embodiments of the invention

[0018] The preferred embodiments of the present invention are explained in more detail below with reference to the drawings.

[0019] First, a design of a dual-clutch transmission relating to the present invention is described with reference to Fig. 2 schematically described, whereby the dual-clutch transmission, on which a mechanism of a 7-speed automatic transmission is applied, is explained as an example.

[0020] Fig. Figure 2 shows a schematic diagram of a dual-clutch transmission relating to the present invention.

[0021] With reference to Fig. 2 The dual-clutch transmission has a first input shaft (INPUT#1) which is intended to receive a drive force from a drive force source, e.g. from a motor, in stages, and a second input shaft (INPUT#2) which is arranged coaxially to the first input shaft (INPUT#1) and is thus intended to receive the drive force from the drive force source in stages.

[0022] The first (INPUT#1) and second input shafts (INPUT#2) are each designed to alternately form a gear according to a range of gear ratios, in conjunction with a separate shifting mechanism. For example, the first input shaft (INPUT#1) is designed to form an odd-numbered gear (first, third, fifth, or seventh gear) in conjunction with the separate shifting mechanism, while the second input shaft (INPUT#2) is designed to form an even-numbered gear (second, fourth, or sixth gear) in conjunction with the separate shifting mechanism.

[0023] Furthermore, the first (INPUT#1) and the second input shaft (INPUT#2) are each coupled to the drive force source via a first (CL1) and a second clutch (CL2) in such a way that the two input shafts can each receive the drive force from the drive force source, i.e. from the motor, in stages, with one of the first (INPUT#1) and the second input shaft (INPUT#2) being designed to form a reverse gear (R gear).

[0024] The separate switching mechanism is essentially arranged parallel to the first (INPUT#1) and second input shafts (INPUT#2) and has a first output shaft (OUTPUT#1) and a second output shaft (OUTPUT#2), these two output shafts being designed to form the multiple gears together with the first (INPUT#1) and second input shafts (INPUT#2) by means of a synchronized switching mechanism with continuous engagement.

[0025] That is, between the first (INPUT#1) or the second input shaft (INPUT#2) and the first (OUTPUT#1) or the second output shaft (OUTPUT#2), the respective, constantly meshing gears of each gear are provided, whereby a state in which the gears of each gear are coupled to the first (OUTPUT#1) or the second output shaft (OUTPUT#2) is changed by means of a conventional synchronizing device, so that the switching from one gear to another is realized.

[0026] The first input shaft (INPUT#1) together with the first output shaft (OUTPUT#1) forms a first and a third gear between them, and also together with the second output shaft (OUTPUT#2) a fifth and a seventh gear between them, thus producing the odd gears, while the second input shaft (INPUT#2) together with the first output shaft (OUTPUT#1) forms a second and a sixth gear between them, and also together with the second output shaft (OUTPUT#2) a fourth and a reverse gear (R-gear) between them, thus producing the even gears.

[0027] That is, the first (INPUT#1) and the second input shaft (INPUT#2) are designed to alternately form a series of gears from the first to the seventh gear, with the second input shaft (INPUT#2) also forming the reverse gear together with the second output shaft (OUTPUT#2) and a separate return shaft (RS).

[0028] The following section will discuss the control of a shifting process in a dual-clutch transmission constructed as described above.

[0029] By means of a method for controlling a shifting process of a vehicle with a dual-clutch transmission according to the present invention, a clutch torque is controlled such that during kickdown shifting, in which a shift to a lower gear is carried out according to the driver's desire to accelerate following operation of an accelerator pedal, the speeds of an input shaft of a target gear and of an engine increase simultaneously, and an engagement of the gears of the target gear is attempted at the time when the speed of the input shaft of the target gear has been synchronized with the speed of the engine, so that a shift delay can be reduced as much as possible.

[0030] It is advantageously provided that, if a shift is performed via a different shaft, where even during kickdown shifting the difference of one gear step between a target gear and a current gear represents a difference of one gear step of one or more odd gears, then a torque of a release-side clutch to which the current gear is connected is constantly reduced, while a torque of an engagement-side clutch connected to the target gear is constantly increased, so that an engagement of the gears of the target gear is attempted in the state in which the speed of the input shaft of the target gear is synchronized with the engine speed, which aims at achieving a fast shift without a feeling of torque interruption.

[0031] It will be explained in more detail below with reference to the other drawings.

[0032] Fig. Figure 3 shows a flowchart illustrating a method for controlling a shifting process according to an embodiment of the present invention, which is used to control a shifting process of a vehicle with a dual-clutch transmission, and Fig. 4 a diagram to illustrate a method for controlling a shifting process of a vehicle with a dual-clutch transmission according to the present invention.

[0033] With reference to Fig. 3 and Fig. 4. The method for controlling a shifting process of a vehicle with a dual-clutch transmission according to the embodiment of the present invention can be divided into five process steps on a large scale.

[0034] It is advantageously provided that the method according to the invention comprises the following process steps: deciding on a shift start (S100), in which it decides whether a kickdown shift has been initiated or not; deciding on a shift via a different shaft (S200), in which it decides whether the shift takes place via a different shaft or not; controlling a clutch torque (S300), in which the control of the clutch torque takes place according to the shift via a different shaft; deciding on a clutch synchronization (S400), in which it decides whether the speed of an input shaft of the target gear and the engine speed have been synchronized with each other or not; and performing a shift (S500) to engage the gears of the target gear.

[0035] In process step S100, a decision is made as to whether or not a kickdown shift is initiated, depending on whether the vehicle's state after driver operation corresponds to the acceleration conditions. The presence of a kickdown shift can be determined using some or all of the information about the differences between the current engine speed and a target speed (synchronous speed of the target gear) set after the accelerator pedal has been pressed.

[0036] For example, if the range of acceleration due to pedal input exceeds a reference value within a defined time period, this can be considered a kickdown, i.e., the use of the accelerator pedal for rapid acceleration. Furthermore, if the range of acceleration due to the target engine speed set after pedal input, compared to the current engine speed, exceeds a reference value, this can also be defined as a kickdown.

[0037] If, as a consequence of the decision in process step S100, it is determined that the kickdown shift has been initiated, then a decision is made as to whether a shift via a different shaft occurs, where a difference of one gear step of one or more odd gears is present even during the kickdown shift (S200). If, at the time the kickdown shift is initiated, the difference (C) between the speed of the input shaft (INPUT#1) of the target gear and the target speed (synchronous speed of the target gear) exceeds a predetermined reference value (Th1 rpm), then this can be determined as a shift via a different shaft (see Fig. 4).

[0038] In a kickdown shift, where there is a one-gear difference between two or more even-numbered gears, the input shaft of the current gear is the same as that of the target gear. Therefore, the rotational speed of the input shaft (INPUT#1) of the target gear at the start of the shift, i.e., at the moment a shift is requested, is identical to the current engine speed, with the difference between the input shaft speed and the target speed being less than the reference value (Th1 rpm). This defines the case as a shift via a common shaft, and thus a shifting process is applied according to a different principle.

[0039] If, as a consequence of the decision in process step S200, it is determined that a current gear position of the vehicle represents a shift via a different shaft, then the clutch torque is controlled such that the speed of the input shaft (INPUT#1) of the target gear increases together with the engine speed increased after the acceleration request (S300). It is advantageously provided that the clutch torque is controlled such that the speed of the input shaft increases together with the engine speed, which increases towards the target speed set by the operation of the accelerator pedal.

[0040] The clutch torque control encompasses both the control of the released torque for a release-side clutch (CL2) between the current input shaft (INPUT#2) and the engine, and the control of the applied torque for an engagement-side clutch (CL1) between the input shaft (INPUT#1) of the target gear and the engine. The released torque control represents the control of the released clutch (CL2), which interrupts the drive force connection between the input shaft (INPUT#2) of the current gear and the engine, while the released torque control represents the control of the engagement-side clutch (CL1), which couples the input shaft (INPUT#1) of the target gear to the engine.

[0041] In process step S300, it is specifically provided that the drive force connection with the input shaft (INPUT#2) of the current gear is released by constantly reducing the torque of the release-side clutch (CL2), and the torque of the engagement-side clutch (CL1) is simultaneously constantly increased from the time when the shift request is entered until the time point for the synchronization decision (f1), so that the speeds of the input shaft (INPUT#1) of the target gear and the engine can be increased simultaneously and thus synchronized with each other.

[0042] In order to synchronize the speeds of the input shaft (INPUT#1) of the target gear and the engine by controlling the torque of the engagement-side clutch (CL1), the clutch torque is controlled such that at the moment when the kickdown shift is initiated, i.e., when the shift is requested, the torque of the engagement-side clutch is allowed to jump to a torque at the start of synchronization (a NM), and then increases at an arbitrary torque change rate (b NM / sec) until the time of decision of synchronization (f1), in which the speeds of the input shaft of the target gear and the engine become almost equal.

[0043] In this process, a value of the torque at the start of synchronization (a NM) and a value of the torque change rate (b NM / sec) each represent the quantities which depend on the difference (c) between the rotational speed of the input shaft (INPUT#1) of the target gear and the target speed, and can thus be recorded in advance through repeated experiments and previous simulations, whereby they can then be automatically selected when a value of the difference (C) between the rotational speed of the input shaft (INPUT#1) of the target gear and the target speed is determined.

[0044] Of course, all methods can be considered which utilize the data obtained through repeated experiments and previous simulations, and then derive certain relations between the difference (C) between the speed of the input shaft (INPUT#1) of the target gear and the target speed on the one hand, and the data on the other, so that the values ​​of the torque at the start of synchronization (a NM) and the torque change rate (b NM / sec) can then be mathematically determined and output when a value of the difference (C) is entered by utilizing the derived relations, or by means of which the values ​​can also be practically derived.

[0045] In process step S400, a decision is then made as to whether the increased speed of the input shaft (INPUT#1) of the target gear, resulting from controlling the torque of the engaged clutch, is synchronized with the engine speed. This synchronization decision can be made using rotational information provided by a detection sensor that measures the rotational speed of the input shaft (INPUT#1) of the target gear, a crankshaft angle sensor that measures the engine speed, and so on.

[0046] In process step S400, the information provided by the sensors mentioned above is first used to determine whether the speed of the input shaft (INPUT#1) of the target gear and the engine speed have reached a point in time for deciding on synchronization (f1), at which the two speeds are equal or similar (S410). Then, a decision is made as to whether the synchronized speeds of the input shaft of the target gear and the engine have reached a point in time for completing synchronization, at which the speeds become equal to the target speed of the engine (synchronous speed of the target gear) (S420).

[0047] If, after comparing the speed of the input shaft (INPUT#1) of the target gear with that of the engine, the speeds of the input shaft of the target gear and of the engine are determined such that they reach the time for deciding the synchronization (f1), at which the speeds are equal or similar, then the torque of the engagement-side clutch (CL1) is maintained at a torque at the time of reaching the time for deciding the synchronization (f1) for any period of time, preferably from the time for deciding the synchronization (f1) until the time for completing the synchronization, at which the engagement of the gears of the target gear is started.

[0048] When the point in time for the completion of synchronization is reached, in which the speeds of the input shaft of the target gear and the engine are identical to the target speed of the engine (synchronous speed of the target gear), the torque of the engagement-side clutch is reduced down to the transmission start point of the clutch torque (TP) and the gears of the target gear are allowed to mesh in this state, so that a smooth shift without shift shock can be achieved.

[0049] In contrast, in process step (S500) for carrying out a switching operation to engage the gears of the target gear, it is provided that when a time (f1) is reached in which the rotational speeds of the input shaft (INPUT#1) of the target gear and of the motor become equal or similar to each other by controlling the applied clutch relative to the engagement-side clutch (CL1), then the control is carried out in such a way that a shift lever of the gears of the target gear is moved to near a synchronization start point and left there so that the gears of the target gear can mesh as quickly as possible.

[0050] According to a start command issued at the time when the speeds of the input shaft (INPUT#1) of the target gear and the engine are increased to the target speed set by the accelerator pedal (target gear synchronization speed) (i.e., at the time when the synchronization of the speed of the target gear with that of the engine is completed), the engagement of the gears of the target gear can take place, so that this engagement can be carried out without a separate synchronization process, which can consequently shorten the shift time.

[0051] The engagement of the gears in the target gear can be achieved by regulating the supply voltage to one of several hydraulically controlled solenoid valves involved in the gear engagement. In other words, the engagement of the gears in the target gear can be achieved by switching an oil path of the hydraulically controlled solenoid valves through voltage regulation, such that oil pressure is supplied to one of several clutches or brakes, which then controls the engagement of the gears in the target gear.

[0052] Fig. Figure 5 shows a diagram comparing the states of the shift delay before and after the improvement of a control of a shifting process of the dual clutch transmission.

[0053] With reference to Fig.5. It is intended that, with the current state of the art, unnecessary "engine control of a release clutch" or "engine control of a release clutch," etc., are required because, during kickdown, where the difference between the synchronization speed of the target gear and the speed of the input shaft of the current target gear is large, the engine speed is increased even faster, even if the gears mesh as quickly as possible. Therefore, there is no alternative but to lengthen the period (the shift delay time) from the time the target speed is reached (the time when the synchronization of the speed of the input shaft of the target gear with that of the engine is complete) until the time the gears disengage.

[0054] In contrast, according to the present invention, a clutch torque is controlled such that during kickdown, the speeds of an input shaft of a target gear and of an engine increase simultaneously, and an engagement of the gears of the target gear is attempted at the time when the speed of the input shaft of the target gear has been synchronized with the speed of the engine, so that the period (the shift delay time) from the time when the target speed is reached (the time when the synchronization of the speed of the input shaft of the target gear with that of the engine is completed) until the time when the engagement of the gears is terminated is considerably shortened compared to the period before the improvement.

[0055] This means that the torque of an engagement-side clutch is controlled in such a way that the increase in the rotational speed of an input shaft, with which the gears of the target gear are coupled, and the increase in the engine speed occur simultaneously before the engagement of the gears of the target gear, so that the shift delay, which occurs during kickdown shifting where the difference between the speed of the input shaft of the target gear and the engine speed is large, can be improved, and thus the feeling of a torque interruption and wear of the clutch due to the shift delay can be minimized. Reference symbol list S100 deciding on the start of a circuit S200 deciding on a circuit via a different wave S300 controlling a clutch torque S400 deciding on clutch synchronization S500 performing a circuit

Claims

[1] Method for controlling a shifting operation of a vehicle with a dual-clutch transmission, the method comprising the following process steps: deciding on the start of a shift (S100), which determines whether a kickdown shift, where, according to the driver's intention to accelerate, the shifting to a lower gear is carried out based on the operation of an accelerator pedal, whether it has started or not; the decision regarding an odd shift (S200), in which it decides whether the shifting via a different shaft, in which a target gear and a current gear differs from each other by one or more odd gear steps, if the kickdown shift has been initiated, has occurred or not; the control of a clutch torque (S300) in which, if a current switching state of a vehicle, which it decided on in the process step for deciding on a switching via a different shaft, is determined to be the switching via a different shaft, then a torque of a release-side clutch is constantly reduced, while a torque of an engagement-side clutch is increased so constantly that a speed of an input shaft of the target gear and an increasing engine speed are synchronized with each other; Deciding on clutch synchronization (S400), in which it decides whether the speed of an input shaft of the target gear and the engine speed have been synchronized with each other by controlling a clutch torque; and the execution of a switching operation (S500) in which, when the speeds of the input shaft of the target gear and the motor have been synchronized, the switching control is then carried out to engage the gears of the target gear, wherein the procedure step for deciding on clutch synchronization (S400) includes a sub-step (S410) for deciding whether the speed of the input shaft of the target gear and the motor speed have reached a time point for deciding on synchronization (f1) in which the two speeds are equal or similar to each other. [2] Method according to claim 1, wherein in the method step for deciding on a start of the circuit it is provided that it decides, by means of part or all of the information on the movement of the accelerator pedal, and the difference between the current engine speed and the target speed set after the operation of the accelerator pedal, whether the kickdown circuit is started or not. [3] Method according to claim 1, wherein in the method step for deciding on a switching via a different shaft it is provided that if, at the time when the kickdown switching is initiated, the difference (C) between the speed of the input shaft of the target gear and the target speed of the engine during downshifting, where a predetermined reference value (Th1 rpm) is exceeded, represents a difference of one gear step of one or more odd gears, then the switching state is determined as the switching via a different shaft. [4] Method according to claim 1, wherein in the process in which the speeds of the input shaft of the target gear and of the engine are synchronized by controlling the clutch torque, it is provided that at the time when the kickdown circuit is initiated, the torque of the engagement-side clutch is allowed to jump to a torque at the start of synchronization (a NM), and then increases at an arbitrary torque change rate (b NM / sec) until the time for deciding on synchronization, in which the speeds of the input shaft of the target gear and of the engine become equal. [5] Method according to claim 4, wherein a value of the torque at the start of synchronization (a NM) and a value of the torque change rate (b NM / sec) each represent the value which is selected from the values ​​which were recorded in advance at the time when the kickdown circuit was initiated, corresponding to the difference (c) between the speed of the input shaft of the target gear and the target speed of the engine. [6] Method according to claim 1, wherein the method step for deciding on clutch synchronization (S400) comprises a sub-step (S420) for deciding whether the mutually synchronized speeds of the input shaft of the target gear and of the engine have reached a point in time for completing the synchronization, in which they become equal to the target speed of the engine or not. [7] Method according to claim 6, wherein, when it is determined such that the speed of the input shaft of the target gear and the engine speed reach the time for the decision of synchronization (f1), the torque of the engagement-side clutch is maintained at a torque at the time of reaching the time for the decision of synchronization (f1) until the time of completion of the synchronization. [8] Method according to claim 6, wherein, when it is determined such that the speed of the input shaft of the target gear and the engine speed have reached the time for completion of the synchronization, then the torque of the engagement-side clutch is adjusted downwards to the transmission start point of the clutch torque (TP) and then the gears of the target gear are allowed to mesh with each other. [9] Method according to claim 1, wherein in the method step of carrying out a circuit it is provided that the engagement of the gears of the target gear is realized by regulating a supply voltage of one of several hydraulically controlled solenoid valves that is involved in the engagement of the gears of the target gear. [10] Method according to claim 9, wherein the hydraulically controlled solenoid valve switches an oil path such that an oil pressure is supplied to one of several clutches or brakes which controls the engagement of the gears of the target gear.

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