Method of controlling the shift to a higher gear with the accelerator pedal released

Abstract

A method for controlling a shift to a higher gear in a power transmission system (6) having a dual-clutch servo-assisted transmission (7) when the accelerator pedal (22) is released, comprising the steps of: opening the disengaging clutch (16A) at a first time (t1); closing the engaging clutch (16B) at the first time (t1); between a second time (t2) and a third time (t4), synchronizing the rotational speed (ω E ) of the internal combustion engine (4) with the rotational speed (ω B ) of the engaging clutch (16B), i.e., synchronizing with the rotational speed (ω B ) imparted by the gear ratio of the subsequent gear (B); fully opening the disengaging clutch (16A) at the third time (t4); fully closing the engaging clutch (16A) at the third time (t4); between the second time (t2) and a fourth time (t3), keeping the torque (T A ) transmitted by the disengaging clutch (16A) constant; and between the second time (t2) and the fourth time (t3), keeping the torque (T B ) transmitted by the engaging clutch (16B) constant.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the priority of Italian Patent Application No. 102019000017543 filed on September 30, 2019, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0003] The present invention relates to a method of controlling a shift to a higher gear (ie a shift where the subsequent or incoming gear is higher than the previous or outgoing gear) with the accelerator pedal released in a powertrain having a dual clutch servo-assisted gearbox. Background Art

[0004] The powertrain with a dual-clutch servo-assisted gearbox comprises: a pair of main shafts, which are coaxial, independent of each other and inserted into each other; two coaxial clutches, each of which is designed to connect the corresponding main shaft to the drive shaft of the internal combustion engine; and at least one secondary shaft, which transmits movement to the drive wheels and can be coupled to the main shaft by a corresponding gear train, each defining a gear.

[0005] During a gear shift, the current gear couples the countershaft to one main shaft, while the subsequent gear couples the countershaft to the other main shaft; as a result, the gear shift is performed by alternating the two clutches, ie by opening the clutch associated with the current gear and simultaneously closing the clutch associated with the subsequent gear.

[0006] Currently, a shift to a higher gear with the accelerator pedal released requires opening the outgoing clutch (i.e. the clutch associated with the previous gear), reducing the speed of the internal combustion engine by the braking torque generated by the internal combustion engine operating in engine braking mode, and finally closing the incoming clutch (i.e. the clutch associated with the subsequent gear). In this way, a synchronization (reduction) between the speed of the internal combustion engine and the speed imparted by the subsequent gear (i.e. by the incoming clutch) is produced when both clutches are open, so that the internal combustion engine is operated in engine braking mode (i.e. the internal combustion engine is in a switched-off state and operates as an engine brake, generating braking torque).

[0007] This mode of execution of the change to a higher gear with the accelerator pedal released is crucial from a control point of view, since, with both clutches remaining open, the step of regulating the engine speed is entirely assigned to the engine alone; it often happens that, in order to subsequently synchronize with a sudden increase, the engine speed is reduced too much so that first a forward pull is produced, followed by a strong backward pull at the moment when the engine speed tries to increase again to reach the speed of the incoming clutch (the overall feeling perceived by the driver is therefore not very pleasant).

[0008] Patent US6881171B2 describes a method for controlling gear shifting in a powertrain having a dual-clutch servo-assisted gearbox, during which the torque at the output of the gearbox is kept constant or varies monotonically, or the longitudinal acceleration of the vehicle varies monotonically. Summary of the invention

[0009] The object of the present invention is to provide a method for controlling the shift to a higher gear when the accelerator pedal is released in a powertrain having a dual-clutch servo-assisted gearbox, which method does not have the above-mentioned disadvantages and is easy and economical to implement.

[0010] According to the present invention, a method for controlling a shift to a higher gear when an accelerator pedal is released in a power transmission system having a dual-clutch servo-assisted gearbox is provided, thereby shifting a current gear to a subsequent gear higher than the current gear. The power transmission system includes a dual-clutch servo-assisted gearbox having: two main shafts; at least one secondary shaft connected to a driving wheel; and two clutches, each of which is interposed between a driving shaft of an internal combustion engine and a corresponding main shaft. The control method includes the following steps:

[0011] disengaging an off-going clutch associated with the current gear at a first moment;

[0012] closing an incoming clutch associated with a subsequent gear at a first moment;

[0013] Between a second moment after the first moment and a third moment after the second moment, synchronizing the speed of the internal combustion engine with the speed of the incoming clutch, i.e., with the speed imparted by the transmission ratio of the subsequent gear;

[0014] fully opening the off-going clutch at a third time; and

[0015] At a third moment, the incoming clutch is fully engaged.

[0016] The control method is characterized in that it further comprises the following steps:

[0017] maintaining the torque transmitted by the off-going clutch constant between a second time instant and a fourth time instant, the fourth time instant being after the second time instant and before the third time instant; and

[0018] The torque transmitted by the incoming clutch is maintained constant between the second time instant and the fourth time instant.

[0019] The appended claims describe preferred embodiments of the invention and form an integral part of the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention will now be described with reference to the accompanying drawings showing non-limiting embodiments of the invention, in which:

[0021] Figure 1 is a schematic plan view of a rear-wheel drive road vehicle provided with a powertrain having a dual-clutch servo-assisted gearbox and controlled according to the control method of the present invention;

[0022] Figure 2 yes Figure 1 A schematic diagram of the powertrain; and

[0023] Figure 3 and Figure 4 Shown are the time developments of the torque transmitted by the two clutches of a dual-clutch transmission, the rotational speed of the drive shaft of the internal combustion engine, the longitudinal deceleration of the road vehicle and the torque generated by the internal combustion engine during a corresponding change to a higher gear by means of the control method according to the invention. DETAILED DESCRIPTION

[0024] exist Figure 1 In the figure, reference numeral 1 generally denotes a road vehicle (in particular a car) having two front driven (ie non-driven) wheels 2 and two rear driven wheels 3. In the front position there is an internal combustion engine 4 having a drive shaft 5 which generates a torque T transmitted to the drive wheels 3 via a drivetrain 6. E The powertrain 6 includes a dual-clutch servo-assisted gearbox 7 disposed in the rear-wheel drive assembly and a transmission shaft 8 connecting the drive shaft 5 to the input end of the dual-clutch servo-assisted gearbox 7. The dual-clutch servo-assisted gearbox 7 is connected to a self-locking differential 9 in a gear train manner, and a pair of half shafts 10 originate from the self-locking differential 9 and are each integral with the drive wheel 3.

[0025] The road vehicle 1 comprises a control unit 11 of an internal combustion engine 4, which controls the internal combustion engine 4, a control unit 12 of a drivetrain 6, which controls the drivetrain 6, and a bus line 13, which is made, for example, according to the CAN (Car Area Network) protocol, extends over the entire road vehicle 1 and allows the two control units 11 and 12 to communicate with each other. In other words, the control unit 11 of the internal combustion engine 4 and the control unit 12 of the drivetrain 6 are connected to the bus line 13 and can therefore communicate with each other by means of information sent via the bus line 13. Furthermore, the control unit 11 of the internal combustion engine 4 and the control unit 12 of the drivetrain 6 can be directly connected to each other via a dedicated synchronization cable 14, which is capable of directly transmitting signals from the control unit 12 of the drivetrain 6 to the control unit 11 of the internal combustion engine 4 without delays caused by the bus line 13. Alternatively, the synchronization cable 14 may not be present and all communications between the two control units 11 and 12 may be exchanged using the bus line 13.

[0026] according to Figure 2 , the dual-clutch servo-assisted gearbox 7 comprises a pair of main shafts 15, which are coaxial, independent of each other and inserted into each other. In addition, the dual-clutch servo-assisted gearbox 7 comprises two coaxial clutches 16, each of which is designed to connect the corresponding main shaft 15 to the drive shaft 5 of the internal combustion engine 4 through the intervention of the transmission shaft 8; each clutch 16 is an oil bath clutch and is therefore pressure-controlled (i.e., the degree of opening / closing of the clutch 16 is determined by the oil pressure in the clutch 16); according to an alternative embodiment, each clutch 16 is a dry clutch and is therefore position-controlled (i.e., the degree of opening / closing of the clutch 16 is determined by the position of the movable element of the clutch 16). The dual-clutch servo-assisted gearbox 7 comprises a single secondary shaft 17 connected to the differential 9, which transmits movement to the drive wheels 3; according to an alternative and equivalent embodiment, the dual-clutch servo-assisted gearbox 7 comprises two secondary shafts 17, both of which are connected to the differential 9.

[0027] The dual-clutch servo-assisted transmission 7 has seven forward gears (1st gear I, 2nd gear II, 3rd gear III, 4th gear IV, 5th gear V, 6th gear VI and 7th gear VII) indicated by Roman numerals and a reverse gear (indicated by R). The main shaft 15 and the countershaft 17 are mechanically coupled to each other through a plurality of gear trains, each of which defines a corresponding gear and includes a main gear 18 fixed to the main shaft 15 and a counter gear 19 fixed to the countershaft 17. In order for the dual-clutch servo-assisted transmission 7 to operate correctly, all odd-numbered gears (1st gear I, 3rd gear III, 5th gear V, 7th gear VII) are coupled to the same main shaft 15, while all even-numbered gears (2nd gear II, 4th gear IV and 6th gear VI) are coupled to another main shaft 15.

[0028] Each main gear 18 is connected to the corresponding main shaft 15 by a spline so as to always rotate in an integral manner with the main shaft 15, and is permanently meshed with the corresponding sub-gear 19; on the other hand, each sub-gear 19 is installed on the countershaft 17 in an idling manner. In addition, the dual-clutch servo-assisted transmission 7 includes four synchronizers 20, each of which is coaxially installed on the countershaft 17, disposed between two sub-gears 19, and designed to be operated to alternately fix the corresponding two sub-gears 19 to the countershaft 17 (that is, alternately make the corresponding two sub-gears 19 angularly integral with the countershaft 17). In other words, each synchronizer 20 can move in one direction to fix one sub-gear 19 to the countershaft 17, or can move in the other direction to fix another sub-gear 19 to the countershaft 17.

[0029] The dual-clutch gearbox 7 comprises a single layshaft 17 connected to the differential 9 , which transmits the movement to the drive wheels 3 ; according to an alternative and equivalent embodiment, the dual-clutch gearbox 7 comprises two layshafts 17 each connected to the differential 9 .

[0030] according to Figure 1 , the road vehicle 1 comprises a passenger compartment accommodating a driving position for a driver; the driving position comprises: a seat (not shown); a steering wheel 21; an accelerator pedal 22; a brake pedal 23; and two paddle shifters 24 and 25, which control a dual-clutch servo-assisted gearbox 7 and are connected to opposite sides of the steering wheel 21. The upshift paddle shifter 24 is operated by the driver (by means of a short pressure) to request an upshift (i.e., to engage a new gear that is higher than and adjacent to the current gear), while the downshift paddle shifter 25 is operated by the driver (by means of a short pressure) to request a downshift (i.e., to engage a new gear that is lower than and adjacent to the current gear).

[0031] In the following, an execution mode of upshifting from a lower current gear A to a higher subsequent gear B when the accelerator pedal 22 is released is described (when the accelerator pedal 22 is released, the internal combustion engine 4 is running in a closed state and acts as an engine brake); that is, the current gear A has a smaller gear ratio than the subsequent gear B (therefore, when the speed of the road vehicle 1 is the same, the current gear A makes the internal combustion engine 4 run faster than the subsequent gear B).

[0032] In the initial situation (i.e. before the gear change), the outgoing clutch 16B is closed in order to transmit the motion to the main shaft 15A, which in turn transmits the motion to the secondary shaft 17 through the engaged current gear A; on the other hand, the incoming clutch 16B is open, thus isolating the main shaft 15B from the transmission shaft 8. Before starting the upshift, the subsequent gear B is engaged in order to connect the main shaft 15B to the secondary shaft 17 through the gear B. When the driver sends a gear change command, the gear change is performed by opening the outgoing clutch 16A in order to disconnect the main shaft 15A (thus the gear A) from the transmission shaft 8 (i.e. the drive shaft 5 of the internal combustion engine 4) and (substantially) simultaneously closing the incoming clutch 16B in order to connect the main shaft 15B (thus the gear B) to the transmission shaft 8 (i.e. the drive shaft 5 of the internal combustion engine 4).

[0033] Figure 3 The manner in which a shift to a higher gear is shown is that the driver issues an upshift command by operating the upshift paddle shifter 24 while releasing the accelerator pedal 22 . Figure 3 Starting from the top it shows:

[0034] shows the speed ω of the internal combustion engine 4 E , the speed of the clutch 16A that is leaving ω A and the speed of the clutch 16B entering B The first diagram of the temporal development of

[0035] The torque T transmitted by the two clutches 16A and 16B is shown. A , T B The second diagram of the temporal development of

[0036] shows the torque T generated by the internal combustion engine 4 E The third diagram of the time development of (before and after the upshift, the internal combustion engine 4 is in the off state, so it operates in the engine braking mode to generate a negative torque T E );as well as

[0037] The fourth diagram shows the time development of the longitudinal acceleration α of the vehicle 1 (it should be noted that since the internal combustion engine 4 generates a negative torque T E , that is, braking is performed, and therefore the vehicle 1 operates in engine braking mode, so the longitudinal acceleration α of the vehicle 1 is always negative, that is, the vehicle 1 is decelerating).

[0038] As soon as the control unit 12 of the driveline 6 receives a gear change command from the driver (time t0), the control unit 12 of the driveline 6 immediately starts filling the incoming clutch 16B, i.e. it immediately starts supplying pressurized oil into the incoming clutch 16B; in fact, the incoming clutch 16B associated with the subsequent gear B can only transmit a significant torque to the rear drive wheels 3 when the filling of the pressurized oil is completed and the pressurized oil therefore exerts a thrust that compresses the plates of the incoming clutch 16B because it cannot occupy more volume in the incoming clutch 16B. As a result, before the incoming clutch 16B associated with the subsequent gear B can actually start to transmit a significant torque to the rear drive wheels 3, it is necessary to wait for a specified delay time interval (usually 80 to 220 thousandths of a second), during which the filling of the incoming clutch 16B is completed by oil. The completion of filling of the incoming clutch 16B is usually monitored by a pressure sensor which detects the oil pressure in the incoming clutch 16B: when the oil pressure in the incoming clutch 16B exceeds a predetermined threshold, this means that the internal volume of the incoming clutch 16B is completely filled, and therefore the oil in the clutch 16B begins to compress. As a result, a moment t1 is established when the oil pressure in the incoming clutch 16B exceeds the predetermined threshold, wherein (after a delay time) the incoming clutch 16B is filled with oil and is ready to transmit significant torque.

[0039] From the time t0 when the drivetrain control unit 12 immediately starts closing the incoming clutch 16B to the time t1 when, after a delay time, the incoming clutch 16B is filled with oil and ready to transmit significant torque, there is no change in the dynamics of the road vehicle 1, i.e., the full torque T generated by the internal combustion engine 4 E (It is the negative torque T E , that is, the braking torque T E , because the internal combustion engine 4 is in the off state and therefore operates as an engine brake) is completely transmitted by the outgoing clutch 16A, just as before the start of the gear change. At time t1, the incoming clutch 16B begins to transmit the torque T B (i.e., torque T B begins to increase), while commanding the off-going clutch 16A to open (ie, torque T A starts to decrease); it should be noted that the opening of the outgoing clutch 16A associated with the current gear A occurs without delay, because the outgoing clutch 16A is already full of pressurized oil and at this stage only part of the oil needs to be discharged by opening the solenoid valve (the action of which is therefore instantaneous).

[0040] Between times t1 and t2, there is a local torque transfer between clutches 16A and 16B: the torque T transmitted by the offgoing clutch 16A isA The torque transmitted by the incoming clutch 16B decreases in a linear ramp between times t1 and t2, and increases in a step-like manner (the amount of increase is less than the torque T transmitted by the outgoing clutch 16A) at time t1. A Subsequently, between time t2 and t3, the torque T transmitted by the two clutches 16A and 16B A and T B The torque T transmitted by the clutch 16A remains constant and is released during this period. A Greater than the torque T transmitted by the incoming clutch 16B B .

[0041] Subsequently, between the instants t3 and t4, there is a complete torque transfer between the two clutches 16A and 16B, i.e. the torque transmitted by the outgoing clutch 16A is gradually reduced to zero (the outgoing clutch 16A is opened by a linear ramp), while the torque transmitted by the incoming clutch 16B is gradually increased (the incoming clutch 16B is closed by a linear ramp), thereby determining the alternation between the two clutches 16A and 16B. The clutches 16A and 16B are opened and closed by means of linear ramps, i.e. the corresponding torque T A and T B Changes (decreases and increases) linearly over time.

[0042] The outgoing clutch 16A is fully opened in the same time required for the incoming clutch 16B to be fully closed; therefore, at time t4, the outgoing clutch 16A is fully open (thus, it is no longer transmitting any torque), while the incoming clutch 16B is fully closed (i.e., transmitting the full torque T of the internal combustion engine 4). E ). There is a shift time between the instants t1 and t4, during which the torque transmitted by the outgoing clutch 16A decreases until it becomes zero, while the torque transmitted by the incoming clutch 16B increases until it reaches the torque T generated by the internal combustion engine 4. E (As mentioned above, the internal combustion engine 4 is in the off state and therefore operates as an engine brake, thereby generating a negative torque T E ), that is, during this period, the outgoing clutch 16A separates itself from the drive wheel 3 and the incoming clutch 16B connects itself to the drive wheel 3.

[0043] The speed ω of the internal combustion engine 4 E Before the gear shift until time t2, it is equal to the speed ω given by the transmission ratio of the current gear position A. A , which during the gear shift is imparted to the speed ω of the subsequent gear ratio B Gradually decreases and becomes equal to the speed ω after the gear shift B .

[0044] There is a synchronization time between the times t2 and t4, during which the speed ω of the internal combustion engine 4 is E The speed ω given by the transmission ratio of the current gear A A The speed ω given by the gear ratio reduced to the subsequent gear B B , that is, the speed ω E With speed ω B In order to reduce the speed of the internal combustion engine 4 ω E , between times t2 and t4, the negative (i.e. braking) torque T generated by the internal combustion engine 4 is used. E .

[0045] The longitudinal acceleration α of the vehicle 1 is approximately constant immediately before the gear change and is equal to the value α A (which is negative because the vehicle is decelerating) and is approximately constant and equal to the value α immediately after the gear change B (It is negative because the vehicle is decelerating and its absolute value is less than the value α A During the gear shift, the longitudinal acceleration of the vehicle 1 changes from the initial value α A Gradually increases to the final value α B .

[0046] exist Figure 3 In the embodiment shown, the internal combustion engine 4 is in a shut-off state before the upshift (therefore, it acts as a brake torque T E The engine brake is operated) and continues to remain closed even after the upshift; that is, the driver keeps the accelerator pedal 22 fully released before, during and after the upshift. However, it may happen that the driver decides to depress the accelerator pedal 22 after requesting the upshift (that is, after time t0) to request the internal combustion engine 4 to generate a positive torque T E (i.e., driving torque); this situation exists when Figure 4 In the embodiment shown, the driver depresses the accelerator pedal 22 at time t5 (e.g., between time t2 and time t3) after requesting an upshift (i.e., after time t0). Obviously, the control unit 12 of the powertrain 6 must complete the upshift that has already started, but can try and respond immediately to the driver's new (and unpredictable) request, giving the driver a feeling of extreme sensitivity; as a result, starting from time t3 (after time t5), the control unit 12 of the powertrain 6 requests the control unit 11 of the internal combustion engine 4 to increase the torque T generated by the internal combustion engine 4. E (upon request of the driver who has depressed the accelerator pedal 22), and at the same time accelerates the closing of the incoming clutch 16B (i.e. closes the incoming clutch 16B more quickly), which obviously now has to transmit a greater torque T overall due to the internal combustion engine 4 being turned on. B .

[0047] In other words, in the case where the driver depresses the accelerator pedal 22 at time t5 (which is after time t1 and before time t4) during upshifting, if time t5 is before time t3, the control unit 12 of the powertrain 6 causes the torque T generated by the internal combustion engine 4 to E It starts to increase from time t3 (according to Figure 4 ), or increases from time t5 if time t5 is after time t3; furthermore, in the case where the driver depresses the accelerator pedal 22 at time t5 (which is after time t1 and before time t4) during upshifting, if time t5 is before time t3, the control unit 12 of the power transmission system 6 accelerates the closing of the incoming clutch 16B from time t3 (according to Figure 4 ), or if time t5 is after time t3, then acceleration starts from time t5.

[0048] The above control methods have different advantages.

[0049] Firstly, the above-described method of controlling the change to a higher gear is very comfortable because a comfortable longitudinal acceleration curve for the road vehicle is determined due to the uninterrupted transmission of torque to the drive wheels 3: in fact, the longitudinal acceleration of the road vehicle changes gradually without gradient reversal from an initial deceleration to a final deceleration that is smaller than the previous one (the transmission ratio becomes larger when upshifting, so that the engine braking has a weaker effect on the dynamics of the road vehicle 1); in this way, the driver always has the feeling of continuous deceleration.

[0050] Furthermore, the above method of controlling the shift to a higher gear does not produce any perceptible metallic noise, since both clutches 16A and 16B are never both open at the same time, and therefore the drivetrain 6 is always "stressed"; i.e., since the gear train of the drivetrain 6 is always "stressed", the play is greatly reduced, and as a result the noise is also greatly reduced.

[0051] The above method of controlling a shift to a higher gear also allows a new strategy (also known as "change of mind") to be implemented, which allows the torque T of the incoming clutch 16B to be adjusted if the driver depresses the accelerator pedal 22 during an upshift. B , thereby allowing the road vehicle 1 to respond more promptly and quickly to the driver's instructions.

[0052] Finally, the control method described above is easy and economical to implement, since it does not require the installation of additional physical components and does not require expansion of the control unit 12 of the powertrain 6 , since no additional computing power is required.

[0053] Reference numerals list

[0054] 1 Road vehicles

[0055] 2 Front wheels

[0056] 3 Rear wheels

[0057] 4 Engine

[0058] 5 Drive shaft

[0059] 6 Powertrain

[0060] 7 Gearbox

[0061] 8 Drive shaft

[0062] 9 Differential

[0063] 10 Half shaft

[0064] 11 Engine control unit

[0065] 12 Powertrain control unit

[0066] 13 Bus lines

[0067] 14 Sync Cable

[0068] 15 Spindle

[0069] 16 Clutch

[0070] 17 Countershaft

[0071] 18 Main gear

[0072] 19 Secondary gear

[0073] 20 Synchronizer

[0074] 21 Steering Wheel

[0075] 22 Accelerator pedal

[0076] 23 Brake pedal

[0077] 24 Upshift paddle shifters

[0078] 25 Downshift paddle shifters

[0079] ω E Speed

[0080] ω A Speed

[0081] ω B Speed

[0082] T E Torque

[0083] T A Torque

[0084] T B Torque

[0085] α Acceleration

[0086] Time t0

[0087] Time t1

[0088] Time t2

[0089] Time t3

[0090] t4 time

[0091] t5

Claims

1. A control method for controlling a shift to a higher gear when an accelerator pedal (22) is released in a powertrain (6) having a dual-clutch servo-assisted gearbox (7) to shift from a current gear (A) to a subsequent gear (B) higher than the current gear (A), wherein the powertrain (6) comprises a dual-clutch servo-assisted gearbox (7) having: two main shafts (15); at least one secondary shaft (17) connected to a drive wheel (3); and two clutches (16A, 16B) each interposed between a drive shaft (5) of an internal combustion engine (4) and the corresponding main shaft (15), The control method comprises the following steps: opening an off-going clutch (16A) associated with the current gear position (A) at a first time (t1); closing an incoming clutch (16B) associated with a subsequent gear (B) at a first time (t1); Between a second time (t2) after the first time (t1) and a third time (t4) after the second time (t2), the speed (ω) of the internal combustion engine (4) is increased. E ) and the speed (ω) of the incoming clutch (16B) B ), that is, the speed (ω) given by the transmission ratio of the subsequent gear (B) B )synchronous; At a third time (t4), the off-going clutch (16A) is fully opened; At a third time (t4), the incoming clutch (16B) is fully closed; Between the second time (t2) and the fourth time (t3), the torque (T A ) remains constant, the fourth moment is after the second moment (t2) and before the third moment (t4); and Between the second time (t2) and the fourth time (t3), the torque (T B ) remain constant; Wherein, between the second time (t2) and the fourth time (t3), the torque (T B ) is less than the torque (T A ); There is a complete torque transfer between the two clutches (16A, 16B) between the fourth moment (t3) and the third moment (t4), that is, the torque (T) transmitted by the outgoing clutch (16A) is A ) gradually decreases to zero, while the torque (T B ) gradually increases, thereby determining the alternation between the two clutches (16A, 16B); There is a synchronization time between the second moment (t2) and the third moment (t4), during which the speed (ω) of the internal combustion engine (4) is E ) from the speed (ω) given by the transmission ratio of the current gear (A) A ) is reduced to the speed (ω) given by the transmission ratio of the subsequent gear (B) B ), that is, the speed (ω) of the internal combustion engine (4) E ) and the speed (ω) given by the transmission ratio of the subsequent gear (B) B )synchronous.

2. The control method according to claim 1, wherein: Between the fourth time (t3) and the third time (t4), the torque (T B ) increases with a first linear ramp.

3. The control method according to claim 2, wherein: Between the fourth time (t3) and the third time (t4), the torque (T A ) decreases with a second linear ramp.

4. The control method according to any one of claims 1 to 3, wherein: At a first moment (t1), the torque (T B ) increases in a step-like manner.

5. The control method according to any one of claims 1 to 3, wherein: Between the first time (t1) and the second time (t2), the torque (T A ) decreases with a third linear ramp.

6. The control method according to any one of claims 1 to 3, wherein: The internal combustion engine (4) is in a shut-down state before shifting to a higher gear and is also in a shut-down state after shifting to a higher gear.

7. The control method according to claim 6, wherein: Before, during and after shifting to a higher gear, the driver keeps the accelerator pedal (22) fully released.

8. The control method according to any one of claims 1 to 3, wherein: The control method further comprises the following steps: detecting depression of an accelerator pedal (22) by a driver during a shift to a higher gear; During a shift to a higher gear, when the driver depresses the accelerator pedal (22) at a fifth time (t5) after the first time (t1) and before the third time (t4), the torque (T E ) starts to increase from the fourth moment (t3), or if the fifth moment (t5) is after the fourth moment (t3), the torque (T E ) starts to increase from the fifth moment (t5).

9. The control method according to any one of claims 1 to 3, wherein: The control method further comprises the following steps: detecting depression of an accelerator pedal (22) by a driver during a shift to a higher gear; During a shift to a higher gear, when the driver depresses the accelerator pedal (22) at a fifth moment (t5) that is after the first moment (t1) and before the third moment (t4), the incoming clutch (16B) is accelerated to close from the fourth moment (t3) if the fifth moment (t5) is before the fourth moment (t3), or the incoming clutch (16B) is accelerated to close from the fifth moment (t5) if the fifth moment (t5) is after the fourth moment (t3).

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