Motor vehicle equipped with a dual-clutch gearbox and a control system for changing gear ratios in a manual mode

Abstract

A motor vehicle (1) has an electronic control unit (10) that controls the engagement of gear ratios in a dual-clutch gearbox (401) based on actions performed by a driver on a control system (500); the latter is provided with a clutch pedal (502) and a tower (501), having a lever (21) for enabling the driver to engage the gears; the electronic control unit (10) is configured so as to preselect a gear based on the driving conditions, determine which is the desired gear that the driver is engaging in the tower (501) via the lever (21), and prevent the rotation of the lever (21) to delay the engagement of the desired gear, if the latter does not correspond to the preselected gear.

Description

[0001] "MOTOR VEHICLE EQUIPPED WITH A DUAL-CLUTCH GEARBOX AND A CONTROL SYSTEM FOR CHANGING GEAR RATIOS IN A MANUAL MODE" .

[0002] Cross-Reference to Related Applications

[0003] This Patent Appl ication claims priority from Italian Patent Application No . 102024000028017 filed on December 10 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0004] Technical Field

[0005] This invention relates to a motor vehicle equipped with a dual-clutch gearbox and a control system for changing gear ratios in a manual mode .

[0006] Background

[0007] In the automotive sector, robotised dual-clutch gearboxes are widely known, where the change of the gear ratio for forward travel is performed by actuators , which can be selectively controlled either in an automatic mode , by control signals from an electronic control unit installed in the motor vehicle , based on appropriate algorithms in response to detected or estimated driving conditions , or in a manual mode , that is , in response to a manual control performed by the driver . In the latter case , there is usually, in any case , oversight of the electronic control unit , which performs a check of the driving conditions and then gives consent , or not , to actually operate these actuators and thus to actually change the gear ratio , in response to the driver manual command .

[0008] Typically, in known solutions , the manual control to change the gear ratio , that is , the gear change , is performed by the driver by operating a gear lever located on a central console between the two front seats of the motor vehicle , or by operating a pair of paddles that are located behind the steering wheel at the driver ' s place . At the same time , as is well known, the motor vehicle has no clutch pedal : when the drivers decide to change the gear ratio , they simply rotate the control member ( that is , the gear lever or the paddles , depending on the adopted solution) , and the displacement of this control member causes the operation of the actuators in the dual-clutch gearbox, through the management of the electronic control unit , which synchronises the engagement / disengagement of the two clutches with the engagement / disengagement of the gearwheels associated with the available gears , so as to obtain a higher or lower gear ratio than the one currently in use .

[0009] Once the manual action on the control member is completed, the control member returns to its original position, thanks to appropriate elastic systems . Each time the driver operates the control member, there is a shi ft to either the next higher gear or the next lower gear, relative to the gear currently in use . In other words , the electronic control unit is configured to control the actuators of the dual-clutch gearbox in response to the driver manual commands , so that the gears are shi fted exclusively in sequential mode .

[0010] With respect to these known solutions , there is a need to increase involvement and driving pleasure of the driver when using the manual mode , j ust described, without sacri ficing the comfort that comes with automatic gear shi fting . In particular, there is a need to of fer a driving experience comparable to the one o f motor vehicles equipped with a conventional clutch pedal , a conventional mechanical ( that is , non-robotised) gearbox and a conventional lever control tower, with which gears can be set non-sequentially, that is , by skipping at least one gear from the one currently in use .

[0011] In fact , as is well known, conventional lever control towers comprise an operating lever mounted to rotate about two mutually orthogonal rotation axes and allow the driver to individually set the various gear ratios available in the gearbox, after depressing the clutch pedal ; at the same time , a mechanical transmission device connects the operating lever to the gearbox, so as to cause engagement of the gear ratio that has been set via the operating lever .

[0012] However, a conventional lever control tower tends to be incompatible with a robotised dual-clutch gearbox, so appropriate improvements are necessary for its use in this context .

[0013] In addition, there is an additional need to adopt a solution that is compatible with an electronic control unit that , by means of appropriate known algorithms , pre-selects the gears : in practice , these algorithms allow the electronic control unit to predict a future gear change operation, based on the driving conditions that are detected or estimated in real time , and control the actuators in the dual-clutch gearbox in advance of the actual manual operation performed by the driver, so as to reduce the time perceived by the driver with regard to changing the gear ratio .

[0014] The purpose of this invention is , therefore , to provide a motor vehicle equipped with a dual-clutch gearbox and a control system for changing the gear ratio in a manual mode , which enables the above requirements to be ful filled and, preferably, is simple and inexpensive to implement .

[0015] Summary

[0016] According to this invention, a motor vehicle is provided as set forth in claim 1 .

[0017] The dependent claims define preferred embodiments according to this invention .

[0018] Brief Description of the Drawings

[0019] In order to better understand this invention, a number of non-limiting embodiments thereof will now be described by way of example with reference to the attached drawings , in which :

[0020] Figure 1 is a simpli fied perspective view of a motor vehicle that is equipped with a dual-clutch gearbox and a control system for changing gear ratios in a manual mode , in accordance with the precepts of this invention; Figure 2 is a schematic view of the dual-clutch gearbox and control system of the motor vehicle in Figure 1 ;

[0021] Figure 3 illustrates , in a simpli fied manner and / or with parts removed for clarity, a lever control tower forming part of the control system visible in Figure 2 ; Figure 4 illustrates , in a simpli fied way and with parts removed for clarity, a first detail of the lever control tower in Figure 3 ;

[0022] Figure 5 is a front view of the detail in Figure 4 ;

[0023] Figure 6 is a side view, with parts removed for clarity, of an operating lever forming part of the lever control tower, and shown in two di f ferent operating positions ; Figures 7 and 8 illustrate , in a perspective view and with parts removed for clarity, an additional detail of the lever control tower in Figures 3- 6 ;

[0024] Figure 9 shows , in side view, the detail in Figures 7 and 8 , in two di f ferent operating positions ;

[0025] Figure 10 is a cross section of part of the lever control tower from Figures 3- 9 , following a hori zontal cross-section plane ;

[0026] Figure 11 is analogous to Figure 9 and shows , on an enlarged scale and with parts in cross section, a di f ferent embodiment for a detail of the lever control tower in the motor vehicle according to this invention; Figure 12 is a diagram of the dual-clutch gearbox visible in Figure 2 , shown in a simpli fied manner and with parts removed for clarity; and

[0027] Figures 13 and 14 are diagrams of algorithms implemented in a motor vehicle electronic control unit according to a preferred embodiment of this invention .

[0028] Description of Preferred Embodiments

[0029] With reference to Figure 1 , reference number 1 denotes a motor vehicle , in particular a car ( illustrated in a simpli fied manner ) , comprising a passenger compartment having a driver ' s seat configured to accommodate a driver . The motor vehicle 1 comprises two front wheels 100 and two rear wheels 200 . In the speci fic example described below, the wheels 200 are drive wheels . Alternatively or in combination with this example , the wheels 100 may be drive wheels .

[0030] With reference to what is schematically illustrated in Figure 2 , the wheels 200 are operated by a drive unit 300 via a transmission assembly 400 , under the control of an electronic control unit 10 . The drive unit 300 comprises an internal combustion engine and / or an electric machine configured to function as both an engine and a generator, in a manner known and not illustrated in detail .

[0031] With reference to the schematic and simpli fied illustration in Figure 12 , the transmission assembly 400 comprises a dual-clutch gearbox 401 and a di f ferential 402 , arranged in series between a drive shaft 403 , which is provided at the output of the drive unit 300 , and two axles 201 that are coupled to the wheels 200 to rotate the latter .

[0032] The dual-clutch gearbox 401 is a known type , so the following discussion is extremely brief and should be considered as non-limiting with regard to the speci fic features described and illustrated, for example with regard to the arrangement and method of supporting the drive shafts , the number of available gears , etc .

[0033] The dual-clutch gearbox 401 comprises two primary shafts 404 and 405 , which extend along an axis 406 in positions coaxial to each other and to the drive shaft 403 , and two clutches 407 and 408 , which are also coaxial along the axis 406 and are actuated in a known manner not described by an actuator device 409 ( schematically illustrated) , controlled by the electronic control unit 10 in such a manner as to disengage the clutches 407 and 408 and thereby decouple the drive shaft 403 from both shafts 404 and 405 and, consequently, from the wheels 200 , and in such a manner as to engage the clutches 407 and 408 alternatively to each other to transmit drive torque from the drive unit 300 to the first shaft 404 or the second shaft 405 , selectively .

[0034] The dual-clutch gearbox 401 further comprises a secondary shaft 410 , which extends along an axis 411 parallel to and spaced apart from the axis 406 and is coupled via a gearwheel 412 transmission to a shaft 413 provided at the input of the di f ferential 402 , to transmit rotary motion to such di f ferential 402 . The latter , then, trans fers the rotary motion to the axles 201 in a known way, not described in detail . Speci fically, the shaft 413 at the input to the di f ferential 402 extends along an axis 414 that is transversal to the axles 201 and is parallel to , and spaced apart from, the axes 406 and 411 .

[0035] The dual-clutch gearbox 401 further comprises a plurality of gearwheels 415 , coaxially mounted on the shafts 404 , 405 and 410 and meshing with each other, in pairs , so as to transmit motion from the shafts 404 and 405 to the shaft 410 and, at the same time, define a plurality of gear ratios for forward travel, and a reverse gear, or reverse.

[0036] Some of the gearwheels 415, indicated by reference 415a, are keyed in fixed positions on the shafts 404, 405, 410, while others, indicated with reference number 415b, are mounted in axially fixed and angularly rotating positions with respect to the shafts 404, 405, 410. Each gearwheel 415b is bi-univocally associated with a respective gear, that is, a respective gear ratio.

[0037] The gear ratios are engaged by the electronic control unit 10 by controlling a plurality of actuators 416. The latter, in a manner known and not described here for sake of conciseness, drive respective engagement members 418, each of which is mounted coaxially to a corresponding shaft 404, 405, 410, in an angularly fixed position and axially adjacent to at least one of the gearwheels 415b. Each engagement member 418 is axially slidable under the action of the corresponding actuator 416 in such a way as to move from a disengagement position towards at least one engagement position and thereby engage the adjacent gearwheel 415b and make it fixed as it rotates.

[0038] One of the shafts 404, 405 (for example, the shaft 405 with corresponding clutch 408) is used for transmitting motion for odd forward gears, that is, the first gear, the third gear, etc., while the other (for example, the shaft 404 with the corresponding clutch 407) is used for transmitting motion for even forward gears (the second gear, the fourth gear, etc.) .

[0039] The diagram in Figure 12 does not show the transmission gearwheels for reverse, for sake of simplicity.

[0040] Considering the set of available forward gears (of which there are six in the particular illustrated example in the accompanying figures ) , the gear ratio to be engaged in the dual-clutch gearbox 401 while driving the motor vehicle 1 can be set via an automatic mode , that is , be set directly by the electronic control unit 10 , or via a manual mode , that is , be set by the driver . In particular, the electronic control unit 10 i s configured to operate in these two modes , which can be selected by the driver by operating an appropriate control ( for example , a button 26b, as described below) .

[0041] More speci fically, according to the automatic mode , the gear ratio is chosen automatically by the electronic control unit 10 on the basis of appropriate algorithms that evaluate the driving conditions of the motor vehicle 1 , detected or estimated in real time , before being engaged by the same electronic control unit 10 by synchronously controlling the actuators 416 and the actuator device 409 . In the manual mode , on the other hand, the driver sets the desired gear by physically acting on a control system 500 ( Figure 2 ) ; the gear ratio will be engaged by the actuators 416 , also controlled by the electronic control unit 10 , taking into account the operations performed by the driver on the control system 500 .

[0042] With reference to Figure 2 , the control system 500 comprises a lever control tower 501 and a clutch pedal 502 , associated with respective sensors that are in data communication with the electronic control unit 10 to provide signals indicative of the operations performed by the driver on these two components (without any mechanical transmission to trans fer these operations to the dual-clutch gearbox 401 ) .

[0043] The clutch pedal 502 is preferably placed at the conventional pedals , to the left of the brake pedal (not shown) , at the driver ' s place . As mentioned above , the control system 500 comprises at least one detection device 505 ( for example , defined by a position sensor ) arranged to detect the displacements and / or the stroke of the clutch pedal 502 and send corresponding signals to the electronic control unit 10 .

[0044] In general , the term " clutch pedal" can be understood to mean any control member arranged at the driver ' s place and movable from a rest condition to a disengagement condition under a physical action of the driver : based on signals transmitted by the device 505 , the electronic control unit 10 controls the actuator device 409 of the dual-clutch gearbox 401 to disengage both clutches 407 , 408 when the clutch pedal 502 is depressed, and to engage the two clutches 407 , 408 alternatively to each other ( that is , the first clutch 407 i f motion is to be transmitted to the wheels 200 in an even gear, or the second clutch 408 i f motion is to be transmitted in an odd gear ) when the clutch pedal 502 is released .

[0045] The device 505 is preferably configured to also detect the intermediate positions between the rest and disengagement conditions , and not only the two end-of-stroke positions , in order to determine the progressive displacement of the clutch pedal 502 during driver operation . At the same time, the electronic control unit 10 controls the actuator device 409 in such a way that , in the clutches 407 and 408 , torque is transmitted that is inversely proportional to the stroke of the clutch pedal 502 . It should be noted that , here and in the following, the term " inversely proportional" is generically understood to mean that there is a bi-univocal relationship where the two correlated quantities vary in opposite directions , without limitation to a speci fic type of proportionality ( linear, quadratic, etc . ) , and possibly with a fixed initial deviation . In particular, the aim is to provide the driver with a driving feeling similar to the one of motor vehicles equipped with conventional mechanical gearbox and clutch pedal .

[0046] The return of the clutch pedal 502 from the disengagement condition to the rest condition is achieved by means of a spring system 506 , having one or more springs , mechanical and / or pneumatic, in a manner known and not described in detail .

[0047] A mechanical device 507 , consisting in, for example , a cam device , is preferably associated with the movement of the clutch pedal 502 to reproduce a certain reaction force , that is , a haptic feedback, when the driver operates the clutch pedal 502 , where this reaction force is predefined, during the design stages , so as to reproduce sensations similar to those perceived by the driver in motor vehicles that are equipped with a conventional clutch pedal ( that is , mechanically connected to the clutch) .

[0048] With reference to Figures 3 , 4 , 5 and 6 , the lever control tower 501 comprises a support frame 2 comprising, in turn, a bottom plate 3 configured to be fixed to a body portion (not illustrated) of the motor vehicle 1 , and two side plates 4 proj ecting upwards from the plate 3 perpendicularly to the plate 3 .

[0049] The lever control tower 501 also comprises a rotating bracket 5 , which extends between the plates 4 , is essentially square-shaped, and is mounted to rotate about a rotation axis 6 essentially perpendicular to the plates 4 .

[0050] The bracket 5 has two opposite support pins 7 , which extend through the plates 4 along the axis 6 , and respectively support , connected, a drum 8 (which will be better illustrated below) and a detection device 9 , in this case an angular position sensor, configured to detect the angular position of the bracket 5 about the axis 6 and to supply a corresponding position signal to the electronic control unit 10 .

[0051] The bracket 5 supports a guide tube 11 , which is mounted inside the bracket 5 , and is rotatably coupled to the bracket 5 to rotate , with respect to the bracket 5 and in a manner that will be better explained below, about a rotation axis 12 perpendicular to the axis 6 .

[0052] The tube 11 has two opposite support pins 13 , which extend through the bracket 5 along the axis 12 , and support , connected, a support block 14 and a detection device 15 , in this case an angular position sensor, configured to detect the angular position of the tube 11 about the axis 12 and to supply a corresponding position signal to the electronic control unit 10 .

[0053] The latter is configured, in turn, to control the operation of the lever control tower 501 in response to signals from the devices 9 and 15 .

[0054] The block 14 supports two contact rollers 16 , which are mounted in diametrically opposite positions to each other with respect to the axis 12 , and are rotatably coupled to the block 14 to rotate , with respect to the block 14 , about respective rotation axes 17 that are parallel to each other and to the axis 12 .

[0055] The rollers 16 cooperate with a shock absorber 18 mounted on the bracket 5 parallel to the axis 6 . The damping device 18 comprises a cylinder 19 and a piston 20 , which proj ects outside the cylinder 19 parallel to the axis 12 , is slidably coupled to the cylinder 19 , and is held in contact with the rollers 16 by a spring 20a interposed between the cylinder 19 and the piston 20 .

[0056] The preload of the spring 20a is selectively controlled by means of a disk 20b slidably engaged in the cylinder 19 and an adj usting screw 20c that is screwed through the cylinder 19 to move the disk 20b along the cylinder 19 .

[0057] The tube 11 is slidably engaged by an operating lever 21 , which proj ects upwards from the tube 11 and the plates 4 , locked upwards by an upper locking plate 22 attached to the free ends of the plates 4 , and allows the gear chosen by the driver to be set , according to the above-mentioned manual mode .

[0058] The lever 21 is pushed, and normally held, in a raised position by a spring 23 interposed between the tube 11 and the lever 21 , and is moved by the driver to a lowered position against the action of the spring 23 .

[0059] The plate 22 is provided with a channel 24 that is transversal , that is , essentially parallel to the axis 6 , and a plurality o f pairs of longitudinal channel 25 ( in this case three pairs of channel 25 ) . The two channels 25 of each pair extend longitudinally, that is , parallel to the axis 12 , in aligned positions and in opposite directions from the channel 24 . Each channel 25 corresponds to the insertion of a corresponding gear via the lever 21 , with a movement from the channel 24 in response to the driver manual command . The channels 25 are therefore distributed along the channel 24 : the two channels 25 of each pair define a respective gear rank, for example the lst-2ndgear rank, the 3rd-4thgear rank and the 5th- 6thgear rank . Considering the forward gears ( that is , excluding reverse ) , the gears of each rank are consecutive to each other .

[0060] In the specific illustrated example , starting with the channel 24 , there is no channel for engaging the reverse gear ; however, according to a preferred embodiment not illustrated, there is also an additional channel 25 , dedicated to the reverse gear .

[0061] Reaching the end-of-stroke position at the end of each channel 25 , by the lever 21 , corresponds in use to the engagement of a corresponding gear ratio in the dual-clutch gearbox 401 , that is , the engagement of a corresponding gearwheel 415b, according to the algorithms implemented in the electronic control unit 10 .

[0062] Insertion of a gear, that is , insertion of the lever 21 into one of the channels 25 , requires prior selection of the corresponding gear rank by the driver . This selection, i f it corresponds to a change in the rank currently in use , requires the lever 21 to be moved along the channel 24 . I f this is not the case, that is , if the gear change takes place within the same rank, the selection of the gear rank does not require any movement of the lever 21 along the channel 24 .

[0063] As far as the rotation of the lever 21 about the axis 12 along the channel 24 is concerned, the shock absorber 18 is configured in such a way as to automatically bring the lever 21 to a neutral central position ( after leaving the lever 21 free to move along the channel 24 ) .

[0064] The lever 21 is mounted so that it can be rotated about the axis 12 along the channel 24 ( for example , from a neutral starting position corresponding to a central pair of channels 25 ) and about the axis 6 along any of the available channels 25 , to engage and disengage the corresponding gear ( in order to engage and disengage the corresponding gear ratio in the dual-clutch gearbox 501 ) .

[0065] The use of the lever 21 is perfectly identical to the one of any gear shi ft lever associated with conventional mechanical gearboxes .

[0066] In fact , in use , to shi ft gears in the lever control tower 501 , and thus to engage a gear ratio other than the one currently in use in the dual-clutch gearbox 401 , the driver performs , in sequence , the same physical operations that must be performed on a motor vehicle equipped with a conventional mechanical gearbox, namely : the driver operates the clutch pedal 502 to bring it into the disengagement condition ( speci fically, it presses the clutch pedal 502 all the way down) ; in response to this operation, the electronic control unit 10 receives a corresponding signal from the device 505 and consequently commands the actuator device 409 to disengage the clutches 407 , 408 , that is , to decouple the drive shaft 403 from the wheels 200 ; the driver rotates the lever 21 about the axis 6 to move it longitudinally, that is , along the channel 25 , which is currently engaged, towards the channel 24 ; in response to this disengagement of the gear previously set in the lever control tower 501 , the electronic control unit 10 receives a corresponding signal from the device 9 , indicating the new position of the lever 21 (which is in the channel 24 ) , whereby it recognises this disengagement ( in practice , the electronic control unit 10 is able to recognise that the driver intends to change the gear ratio , or simply intends to put the gear in neutral ) ; the driver selects the rank to which the desired new gear belongs , by rotating the lever 21 about the axis 12 along the channel 24 i f needed; in other words , the driver positions the lever 21 along the channel 24 at the pair of channels 25 ( that is , the rank) to which the desired new gear belongs ; at the same time , the electronic control unit 10 receives a corresponding signal from the device 15 , indicative of the position of the lever 21 about the axis 12 , and thus indicative of the selected gear rank; the driver moves the lever 21 about the axis 6 along one of the two channels 25 belonging to the selected rank, starting from the channel 24 , to engage the desired new gear ; in response to this engagement in the channel 25 that has been chosen, the electronic control unit 10 receives a corresponding signal from the device

[0067] 9 , indicative of the movement of the lever 21 about the axis 6 , and thus indicative of the desired new gear being set by the driver ; the set new gear corresponds to a respective gearwheel 415b, that is , a respective gear ratio , which is to be engaged in the dual-clutch gearbox 401 ; this engagement may possibly be performed in advance of the command executed by the driver on the lever 21 , thanks to appropriate gear pre-selection algorithms , implemented in the electronic control unit

[0068] 10 , as will be described in more detail below; the driver releases the clutch pedal 502 , which automatically returns to its rest condition; in response to this return, the electronic control unit 10 receives a corresponding signal from the device 505 and, consequently, commands the actuator device 409 to engage one of the clutches 407 , 408 , that is , the one relating to the new gear ratio which has been j ust engaged, to transmit motion to the wheels 200 .

[0069] The processing of the signals emitted by the devices 505 , 9 and 15 , and the operations performed by the electronic control unit 10 to engage the gear ratio corresponding to the new gear set in the lever control tower 501 , will be described in more detail below, with reference to the algorithms schematically depicted in Figures 13 and 14 .

[0070] With reference to what is shown in Figure 4 , preferably, the lever control tower 501 comprises a plurality of control buttons 26a and a setting button 26b, which are arranged for example on the plate 22 and are connected to the electronic control unit 10 ; the buttons 26a define respective functions for operating the dual-clutch gearbox 401 according to the above-mentioned automatic mode ; the button 26b, on the other hand, allows use of the manual mode or of the above-mentioned automatic mode to be selectively set .

[0071] According to a non-illustrated embodiment , the button 26b is absent , and the operating mode switches from "automatic" to "manual" when the driver presses the clutch pedal 502 , for example , when the clutch pedal stroke 502 exceeds a given threshold; according to another embodiment , this switch from "automatic" to "manual" mode is achieved by operating the clutch pedal 502 , but only i f the vehicle forward speed meets a predefined constraint , for example , only i f the speed is below a given threshold .

[0072] According to another embodiment , not illustrated, the plate 22 and the buttons 26a are removed and replaced with a di f ferent closure plate (not illustrated) with an additional slot , which is parallel to the channels 25 , defines two opposite channels analogous to these channels 25 , and is associated with the automatic operating mode of the dual-clutch gearbox 401 , without being related to the gear ranks described above . In particular, the automatic mode gives the driver the possibility to set the following functions or operating conditions : forward gear, reverse gear, and a neutral " idle" condition . In the lever control tower 501 , these settings can be made according to two alternative embodiments , that is , via the buttons 26a, or via the same lever 21 , slid along the additional slot mentioned above .

[0073] In particular, the lever 21 is provided with a coupling pin 27 , which proj ects from the lever 21 through the tube 11 and parallel to the axis 12 , and i s movable , as a result of the movement of the lever 21 about the axis 12 , along a guide track 28 formed on the outer surface of the tube 11 . In the embodiment (not illustrated) in which the additional slot is provided, in order to set the automatic mode , preferably the lever 21 must first be moved to its lowered position against the action of the spring 23 to disengage the pin 27 from the track 28 , it must then be moved about the axis 12 along the channel 24 to reach the additional slot , and to engage the pin 27 in a seat 29 formed at the corresponding end of the track 28 , and it must finally be moved about the axis 6 along this additional slot .

[0074] In the embodiment with an additional slot , mentioned above , it should be noted that : at the intersection between the channel 24 and the additional slot , the lever 21 is in a position to set the neutral " idle" condition; at one of the two end-of-stroke positions along the additional slot about the axis 6 , the lever 21 is in a position to set the " forward travel" in automatic mode ; and at the opposite end-of-stroke position, along the additional slot , the lever 21 is in a position to set the "reverse gear" condition .

[0075] With reference to Figures 7 - 9 , the drum 8 is angularly coupled fixed to the bracket 5 to rotate about the axis 6 together with the bracket 5 and the lever 21 . At one of its radial ends , the drum 8 has three seats 30a, 30b and 30c, which are located side by side along an arc of a circle about the axis 6 . The first seat 30b is centrally located between the second seats 30a and 30c and is preferably equally, angularly spaced apart from the seats 30a and 30c about the axis 6 .

[0076] The radial end of the drum 8 on which the seats 30a, 30b and 30c are formed is shaped like a cam, in such a way as to mechanically reproduce a reaction load corresponding to the engagement and disengagement of the gear by the driver, during the rotation of the drum 8 about the axis 6 , cooperating with a retention unit 32 that is preferably arranged in a pos ition aligned with the same drum 8 along a direction 33 , for example parallel to the axis 12 .

[0077] The lever control tower 501 comprises two retention units , denoted with reference numbers 31 and 32 , which are , for example , provided in diametrically opposite positions with respect to the drum 8 and the axis 6 , along the direction 33 , and are each configured to prevent , or at least limit , the rotation of the assembly defined by the drum 8 , the bracket 5 and the lever 21 , about the axis 6 under certain operating conditions , described in detail below .

[0078] With particular reference to Figure 9 , the unit 31 comprises an electrically operated actuator 34 , for example an electromagnetic actuator ( that is , a solenoid) , which is fixed to the frame 2 and acts directly or indirectly on a retention member, consisting of , in particular, a rod 35 , which extends along the direction 33 and is coupled to the frame 2 and / or the actuator 34 in such a way that it can translate along the direction 33 .

[0079] More speci fically, the rod 35 supports a coupling rolling element , for example a rol ler 36 , mounted on an axial end of the rod 35 so that it can rotate idly about an axis 37 parallel to the axis 6 .

[0080] The unit 31 preferably comprises a groove 38 formed on the side surface of the drum 8 , for example in a position diametrically opposite the seat 30b, and at the same time the rod 35 is movable along the direction 33 from a forward stop position, wherein the end of the rod 35 , that is , the roller 36 i f provided, engages the groove 38 in order to hinder the rotation of the drum 8 about the axis 6 ; in general , this retention action can only be achieved i f the lever 21 is in an angular position such that it engages the channel 24 .

[0081] The rod 35 is pushed by a spring 39 towards the forward stop position, that is , radially towards the drum 8 and axis 6 . In particular, the spring 39 is arranged between a fixed shoulder of the actuator 34 and the rod 35. In other words , the preload of the spring 39 makes it possible to reach and maintain the forward stop position . In the embodiment illustrated in Figure 9 , the preload of the spring 39 is suf ficiently high to achieve the above-mentioned retention action .

[0082] This retention action obviously only takes place i f the drum 8 is arranged, about the axis 6 , in an intermediate position in which the groove 38 is aligned with the rod 35 along the direction 33 and is engaged by the rod 35 ; due to the retention action, the rotation of the lever 21 is hindered by the rod 35 , so that it is rather di fficult ( i f not impossible ) for the driver to rotate the lever 21 into the end-of-stroke position in the channels 25 .

[0083] The forward stop position of the rod 35 preferably does not completely prevent rotation about the axis 6 from the channel 24: in fact, the driver could still force the rotation of the lever 21 to overcome the preload of the spring 39.

[0084] At the same time, by translating along the direction 33 against the action of the spring 39, the rod 35 can reach a rear release position, wherein the roller 36 disengages the groove 38, so that the drum 8 is free to rotate about the axis 6 and, therefore, the lever 21 is free to reach the bottom of the channels 25 starting from the channel 24 to actually set the new gear that the driver wants.

[0085] In the specific example shown in Figure 9, the rear release position is achieved by activating the actuator 34 (controlled in turn by the electronic control unit 10) against the elastic action of the spring 39.

[0086] In use, when any one of the gears is already set in the lever control tower 501, that is, when the lever 21 is arranged, about the axis 6, in the end-of-stroke position along one of the channels 25, the groove 38 is not aligned with the trajectory of the rod 35 along the direction 33, so that it cannot be engaged by the rod 35, even if the latter is pushed by the spring 39. Specifically, when the actuator 34 is deactivated, under the thrust of the spring 39, the axial end of the rod 35 with the roller 36 rests against the side surface of the drum 9, in a position adjacent to the groove 38, as shown in Figure 9(b) .

[0087] Therefore, when any of the gears is already set, that is, the lever 21 is placed in the end-of-stroke position at the end of one of the channels 25, the unit 31 is configured in such a way as to always leave the rotation of the drum 8, and thus the lever 21, about the axis 6 towards the channel 24 free.

[0088] When the electronic control unit 10 supplies electricity to the actuator 34 to fully release the lever 21 , in practice consent is obtained to set the desired new gear in the lever control tower 501 ( after selection of the corresponding gear rank along the channel 24 ) .

[0089] When the actuator 34 is deactivated, then the spring 39 brings the retention member consisting in the rod 35 back to the forward stop position .

[0090] However, displacements of the retention member def ined by the rod 35 between the forward stop position and the rear release position could be achieved in a di f ferent way than described above with reference to Figure 9 .

[0091] In this regard, Figure 11 illustrates a di f ferent embodiment for the unit 31 , whose constituent parts are indicated by the same reference numbers used in the other figures , but followed by the reference letter "a" .

[0092] In this case , the preload of the spring 39a is relatively low, that is , it does not exert the above- mentioned retention action, but only a positioning function to bring the retention member ( defined by the rod 35a ) into the forward stop position . The rod 35a can therefore move almost freely into the rear release position when the lever 21 is rotated by the driver about the axis 6 from the channel 24 . In fact , i f the lever 21 is rotated when the actuator 34a is deactivated, the profile of the groove 38a, by means of appropriate ramps 38b, causes a compression of the spring 39a ( essentially without ef fort ) and, therefore , the retraction of the rod 35a into the rear release position .

[0093] In particular, the groove 38a has a bottom surface 38c between the two ramps 38b, along the circumferential direction about the axis 6 ; the ramps 38b are oriented with opposite inclinations , diverging from each other starting from the bottom surface 38c . When the lever 21 engages the channel 24 and the rod 35a is in the forward stop position, the end of the rod 35a ( consisting, in particular, of a ball 36a performing the same function as the roller 36 ) is coupled to the bottom surface 38c ; when the lever 21 is rotated about the axis 6 by the driver to engage the desired new gear, the end of the rod 35a ( that is , the ball 36a ) slides supported along the bottom surface 38c and then engages one of the two ramps 38b, which is shaped so as to cause the rod 35a to retract along the direction 33a, with the consequent compression of the spring 39a . In practice , these two ramps 38b exploit the physical principle of the inclined plane . At the same time , the thrust of the spring 39a tends to bring the lever 21 back towards the channel 24 ( that is , bring the ball 36a back towards the centre of the bottom surface 38c ) .

[0094] More generally, the groove 38a has dimensions and / or a shape such that it leaves a predetermined clearance , that is , a predetermined freedom of movement about the axis 6 , to allow the device 9 to detect lever 21 rotations performed by the driver, even i f the retention member consisting in the rod 35a is in the forward stop position .

[0095] At the same time , the actuator 34a is configured so that it brings and locks the rod 35a in the forward stop position when it is activated, that is , when it is powered by the electronic control unit 10 . In other words , when activated, the actuator 34a provides a force that is added to the positioning thrust exerted by the spring 39a and defines the above-mentioned retention action . In this operating condition, the ramps 38b of the groove 38 prevent rotation of the drum 8 and lever 21 about the axis 6 ( j ust as in the embodiment in Figure 9 ) .

[0096] Again, the driver could theoretically force the rotation of the lever 21 towards the bottom of the channels 25 , i f they exceeded the force applied by the actuator 34a .

[0097] In addition to these features relating to the operation of the actuator 34a, to the preload of the spring 39a and to the shape of the groove 38a, the embodiment in Figure 11 preferably also di f fers from that of Figure 9 in that the direction 32a along which the rod 35a runs is not aligned / coinciding with the direction 33 of the unit 32 .

[0098] With reference to Figure 10 , with regard to the unit 32 , the latter preferably comprises a guide 40 , for example in the form of a cylinder, and a retention member 41 having an end engaging one of the seats 30a, 30b, 30c of the drum 8 , that is , engages the seats 30a, 30b, 30c alternatively to each other . Considering the rotation about the axis 6 , i f the lever 21 is in the intermediate position at the channel

[0099] 24 , the seat 30b is aligned with the member 41 and is engaged by the latter, in a releasable manner ; i f , on the other hand, the lever 21 is in one of the two opposite operating positions , at the end-of-stroke positions in the channels

[0100] 25 , the member 41 engages one of the two seats 30a and 30c ( depending on which of the two gears belonging to the same gear rank has been set ) , in a releasable manner .

[0101] The member 41 is slidably coupled to the guide 40 along the direction 33 to assume a stop configuration, in which it blocks , or at least strongly limits , the rotation of the drum 8 , and thus the rotation of the bracket 5 and lever 21 , about the axis 6 , and a release configuration, in which the drum 8 , with the bracket 5 and lever 21 , is free to rotate about the axis 6 .

[0102] The member 41 comprises a pin element 42 , which engages the cylinder 40 , and a ball element 43 , which is positioned between the pin element 42 and the drum 8 and selectively engages one of the seats 30a, 30b, 30c . The pin element 42 comprises , in turn, a support rod 44 , which is slidably coupled to the guide 40 to translate between the stop configuration and the release configuration, and is preferably provided with a coupling roller 45 mounted at the opposite end from the ball element 43 , considering the direction 33 . The roller 45 rotates idly with respect to the rod 44 about an axis 46 orthogonal to the direction 33 . The pin element 42 also comprises a push rod 47 , which is aligned with the rod 44 and the ball element 43 along the direction 33 and is arranged abutting against the ball element 43 to push the latter under the action of a preloaded spring 48 so as to keep the ball element 43 selectively engaged in one of the seats 30a, 30b, 30c .

[0103] The spring 48 is preferably arranged between the push rod 47 and a shoulder of the rod 44 in such a way as to exert a thrust tending to move these two components away from each other .

[0104] In the release configuration, the rod 44 is suf ficiently spaced from the push rod 47 , and the preload of the spring 48 is low enough that the ball element 43 and the push rod

[0105] 47 are free to retract together towards the rod 44 , against the thrust of the spring 48 , by a suf ficient amount to cause the j ump into a di f ferent seat 30a, 30b, 30c . In other words , in this operating condition, as a result of the cam shape of the drum 8 at the seats 30 , when the lever 21 is rotated about the axis 6 , the ball element 43 first retracts towards the rod 44 , compressing the spring 48 , and then snaps inside the adj acent seat 30a, 30b, 30c, under the thrust of that spring 48 . As mentioned above , the compression of the spring

[0106] 48 and the j ump of the ball element 43 between the various seats 30a, 30b, 30c mechanically reproduce a predefined reaction load, that is , haptic feedback, related to the operations of engaging and disengaging the gears , that is , to the rotation operations of the lever 21 about the axis 6 .

[0107] In the stop configuration, illustrated as an example in Figure 10 , the rod 44 is suf ficiently close to the push rod 47 to define a shoulder preventing the ball element 43 from retracting far enough to allow the lever 21 to rotate and thus prevents that ball element 43 from j umping into an adj acent seat 30a, 30b, 30c .

[0108] To configure the unit 32 , the latter preferably comprises an actuating device 49 , movable between a locking position, in which it moves and keeps the rod 44 in the stop configuration, and a release position, in which it allows the rod 44 to translate along the direction 33 towards the release configuration, under the thrust of the spring 48 .

[0109] The device 49 comprises , in this case , an electrically driven actuator 50 , for example an electromagnetic actuator ( that is , a solenoid) , which is fixed to the frame 2 and drives a rod 52 , sliding along a direction 51 transversal to the direction 33 , for example parallel to the axis 6 .

[0110] The rod 52 is provided with a groove 53 formed on its outer surface , and is movable in the direction 51 between said release position and said locking position . In the former, the groove 53 is aligned with the roller 45 along the direction 33 and is engaged by the roller 45 to allow the rod 44 to be suf ficiently di stanced from the push rod 47 , which can therefore retract under the thrust of the drum 8 during its rotation about the axis 6 ; in the locking position, on the other hand, the roller 45 does not engage the groove 53 , but rests on the outer surface of the rod 52 , which therefore keeps the rod 44 in a position close to the push rod 47 , against the action of the spring 48 . In other words , the outer surface of the rod 52 defines a shoulder preventing the rod 44 from moving away from the push rod 47 , that is , it prevents the member 41 from assuming its release configuration .

[0111] The rod 52 is pushed, and normally held, in its locking position by a spring 54 , which is interposed between a fixed shoulder and that rod 52 ; the latter is moved from its locking position into its release position against the action of the spring 54 by the electronic control unit 10 , electrically powering the actuator 50 .

[0112] To switch the unit 32 between the stop and release configurations , a system other than the actuating device 49 could, in any case , be adopted . For example , the unit 32 could comprise an actuator acting directly on the rod 44 , for example a relatively powerful solenoid to exert the force required to maintain the stop configuration .

[0113] The electronic control unit 10 commands the actuator 50 , to move the rod 52 and thus switch the unit 32 between the release configuration and the stop configuration, in response to an actuation of the clutch pedal 502 . In fact , i f the driver does not operate the clutch pedal 502 to bring it to the disengagement position, the lever 21 will not be able to rotate about the axis 6 to disengage and engage the gears .

[0114] More speci fically, the electronic control unit 10 is configured via algorithms that , in a preferred embodiment of this invention, are illustrated in the block diagrams in Figures 13 and 14 .

[0115] In these diagrams : the words " solenoid 1 activated" mean that the unit 32 is in the release configuration ( in the speci fic case illustrated, the actuator 50 is electrically powered) ; the words " solenoid 1 deactivated" mean that the unit 32 is in the stop configuration ( in the speci fic case illustrated, the actuator 50 is not powered) ; the words " solenoid 2 deactivated" mean that the unit 31 does not exert any retention action on the lever 21 ( in this speci fic case , reference may be made to the embodiment in Figure 11 , where the actuator 34a must be activated in order to keep the retention member of the unit 31 in the forward stop position and exert the retention action) ; the words " solenoid 2 activated" mean that unit 31 exerts the retention action on the lever 21 ; the term " clutch pedal" means the displacement and / or position of the clutch pedal 502 , from the rest condition towards the disengagement condition, set by the driver and determined based on the detections of the device 505 ; the term "closed clutch" mean that one of the two clutches 407 , 408 is fully engaged; the term "clutch torque" means the torque transmitted from the drive shaft 403 to the wheels 200 at the clutches 407 , 408 ; the term "gear lever" means the angle of rotation of the lever 21 about the axis 6 , set by the driver and determined based on the signals of the device 9, from a reference position wherein the lever 21 is at the channel 24 .

[0116] With reference to Figure 13 , the block 1000 identi fies an initial condition, corresponding to a normal running condition, wherein : the clutch pedal 502 is in the rest condition; in the lever control tower 501 , one of the gears is engaged, that is , the lever 21 is in the end-of-stroke position at the end of one of the channels 25 ; in the dual-clutch gearbox 401 , the gear ratio corresponding to the engaged gear is engaged; one of the two clutches 407 , 408 is engaged, so that torque is transmitted to the wheels 200 with the set gear ratio .

[0117] In this initial condition, the unit 32 is in the stop configuration to lock the rotation of the lever 21 about the axis 6 ; in the preferred embodiment illustrated, the actuator 50 is not powered, as explained above . At the same time , the unit 31 does not constrain the rotation of the lever 21 about the axis 6 .

[0118] When the clutch pedal 502 is actuated by the driver, and its displacement ( from the rest condition) reaches and exceeds an first threshold, set by design and referred to as TH_RELD (block 1001 ) , the electronic control unit 10 commands the actuator device 409 in such a way that it begins to disengage the clutch that was previously engaged and thus proportionally reduce the torque transmitted from the drive shaft 403 to the di f ferential 402 (block 1002 ) . At the same time , in the absence of the button 26b, the operating mode is switched from "automatic" to "manual" .

[0119] According to a variant not illustrated, the blocks 1001 and 1002 may be absent , especially i f the button 26b is actually provided on the lever control tower 501 .

[0120] I f the stroke o f the clutch pedal 502 reaches and exceeds a second threshold, which is set by design, is greater than the first threshold, and is indicated as TH_SOL (block 1003 ) , the electronic control unit 10 commands the actuator 50 to switch the unit 32 from the stop configuration to the release configuration (block 1004 ) . In response to this command, the lever 21 becomes free to rotate about the axis 6 .

[0121] At block 1005 , the electronic control unit 10 checks , based on signals from the device 9 , whether the lever 21 has actually left its initial position to reach the channel 24 . For example , based on the signals from the device 9 , it checks whether the angle of the lever 21 with respect to the above-mentioned reference position has become smaller than a third threshold, set by design and indicated as TH_SOL2 . In this operating condition (block 1006 ) , the unit 31 exerts the retention action in the forward stop position : this retention action is obtained by switching the actuator 34a in the embodiment in Figure 11 , while in the embodiment in Figure 9 it is s imply obtained in response to the rotation of the lever 21 towards the channel 24 by the spring 39 .

[0122] As a result, the unit 31 hinders the engagement of a new gear, awaiting subsequent consent from the electronic control unit 10 .

[0123] At block 1007 , the electronic control unit determines whether the driver is engaging a new gear . For example , based on the signals from the device 9 , it checks whether the angle of the lever 21 with respect to the above-mentioned reference position has become greater than a fourth threshold, set by design and indicated as TH_CAVA.

[0124] As mentioned above , the lever 21 is able to partially rotate about the axis 6 from the channel 24 ( although the unit 31 exerts its retention action) , essentially due to the shape of the groove 38a . In other words , the unit 31 does not completely lock the rotation o f the lever 21 , but limits the angular movement to prevent the lever 21 from reaching the end-of-stroke position at the end of the channel 25 chosen by the driver . Therefore , considering the capacity to detect the rotation of the lever 21 , essentially due to the extension of the bottom surface 38c of the groove 38a between the two ramps 38b, the electronic control unit 10 recognises the driver attempt to engage the lever 21 in one of the channels 25 . At this point , the electronic control unit 10 determines which is the desired new gear the driver is engaging, based on the signals from both the devices 9 and 15 . At block 1008 , preferably, the electronic control unit 10 checks whether this new gear that the driver is engaging, that is , the corresponding gear ratio , is compatible with the actual driving conditions ( in particular with the engine speed) , detected or estimated in real time , according to known control logics , which are not described here for the sake of conciseness .

[0125] I f the gear the driver tries to engage is not compatible with the operating data ( for example , the engine speed, for safety reasons ) , the unit 31 continues to hinder the rotation of the lever 21 , to prevent it from reaching the end-of- stroke position at the end of the channel 25 chosen by the driver . Speci fically, in the embodiment in Figure 11 , it is the force exerted by the actuator 34a, in combination with the ramps 38b of the groove 38a, stopping the rotation of the lever 21 towards the bottom of the channels 25 . Due to the shape of the ramps 38b, the reaction perceived by the driver preferably does not correspond to a complete locking but to extreme di f ficulty in engaging the new gear .

[0126] With reference to Figure 14 , as mentioned above , the electronic control unit 10 performs a further check (block 1009 ) , that is , it compares the new desired gear that the driver is engaging with a gear that has been pre-selected by the electronic control unit 10 based on the appropriate algorithms , of a type known and not described in detail , which in turn are based on driving conditions detected or estimated in real time .

[0127] More speci fically, the electronic control unit 10 is configured so as to : process data on driving conditions that are detected or estimated in real time ; based on this processing, make a prediction of what will be , in the near future , the most appropriate gear ratio , with respect to the gear ratio associated with the gear immediately above and the gear ratio associated with the gear immediately below, in relation to the gear currently in use , and then make a pre-selection of one of either the gear immediately above or the gear immediately below . In particular, this pre-selection procedure is based on the driver physical actions on the vehicle pedals . More speci fically, i f the accelerator pedal is depressed, the gear immediately above is preselected, and i f the brake pedal is depressed, or i f the accelerator pedal has been released for a predefined time ( a few seconds ) , the gear immediately below is preselected . Even more speci fically, the gear immediately below is also preselected when the accelerator pedal is depressed after the clutch pedal 502 has been fully depressed ( since a so-called "double-declutching" manoeuvre on the pedals is recognised) ; command the actuators 416 to engage the gearwheel 415b, which is associated with the preselected gear, before the driver actually actuates the lever 21 in the lever control tower 501 , that is , engaging the gear ratio associated with the preselected gear within the dual- clutch gearbox 401 in advance .

[0128] In other words , when the driver engages the desired new gear, by rotating the lever 21 from the channel 24 to engage one of the two channels 25 belonging to the selected rank, the electronic control unit 10 will tend to have already engaged the gearwheel 415b associated with the pre- selected gear, in order to make it fixed with the corresponding shaft 404 , 405 , 410 and thus make the shi ft to the new gear ratio that has been pre-selected faster .

[0129] I f the new gear desired by the driver, and identi fied based on the detections of the devices 9 and 15 , actually corresponds to the pre-selected gear, at block 1010 the electronic control unit 10 immediately switches the unit 31 , that is , it promptly deactivates the actuator 34a ( in the embodiment in Figure 11 ) , so that the retention action on the drum 8 is eliminated; in this way, the rotation of the lever 21 is free so that it can reach the end-of-stroke position at the end of the channel 25 that has been chosen by the driver .

[0130] On the other hand, it may happen that the driver, by rotating the lever 21 from the channel 24 after selecting the gear rank, tries to engage a new gear that does not correspond to the gear that was preselected by the electronic control unit 10 , for example a new gear that is not immediately higher or immediately lower than the one previously engaged .

[0131] In this case , at block 1011 , the electronic control unit 10 commands the actuators 416 to engage the actual gearwheel 415b ( that is , the gear ratio ) that corresponds to the new gear desired by the driver . Only i f necessary, it drives the actuators 416 to disengage the gearwheel 415b, which corresponded to the preselected gear . In fact , depending on the actual layout of the gearwheels 415b and the actual value of the new gear engaged by the driver, it may not be essential to immediately disengage the gear 415b that was associated with the preselected gear . This can happen, for example , when the driver, when engaging a new gear, skips only one gear from the one previously engaged, thus remaining in the even gear range i f the previous gear was even, or remaining in the odd gear range i f the previous gear was odd .

[0132] Also at block 1010 , the electronic control unit 10 deactivates the actuator 34a to eliminate the retention action exerted by the unit 31 , but with a time delay, compared to the similar deactivation at block 1010 . This time delay preferably corresponds to a stored value , for example a few milliseconds . Alternatively, the retention action exerted by the unit 31 is removed with a delay corresponding to the time required to engage the new gear ratio , corresponding to the gear required by the driver .

[0133] After removal of the retention action, the lever 21 is able to rotate freely about the axis 6 and is able to reach the end-of-stroke position at the end of the channel 25 chosen by the driver .

[0134] As soon as these operations are completed, the procedure returns to the same level as block 1010 described above .

[0135] At this point , the electronic control unit 10 checks whether the lever 21 has actually reached its end-o f-stroke position in the chosen channel 25 , via the signals of the device 9 (block 1015 ) . More speci f ically, it checks whether the angle of the lever 21 with respect to the above-mentioned reference position has exceeded a fi fth threshold that is set by design, is greater than the fourth threshold and is indicated as TH_TQ . I f this is the case , the unit 32 is switched from the release configuration to the stop configuration commanding the actuator 50 , that is , in the speci fic case illustrated by removing power from the actuator 50 (block 1016 ) .

[0136] Finally, when the clutch pedal 502 is released, the electronic control unit commands the actuator device 409 to engage the clutch 407 , 408 which allows motion to be transmitted to the wheels 200 with the gear ratio that has j ust been engaged . In particular, when the stroke of the clutch pedal 502 returns below the first threshold TH_RELD (block 1017 ) , the clutch 407 , 408 corresponding to the set gear ratio is fully engaged, thus returning to the initial condition of block 1000 .

[0137] From the above , it is clear that the control system 500 allows gears to be shi fted in a manual mode that corresponds exactly to what is done with conventional single-clutch mechanical transmissions , even i f the robotised dual-clutch gearbox 401 is used . In particular, the use of a known dualclutch gearbox allows the automatic mode of gear shi fting to be maintained without altering the corresponding management and control algorithms , to the benefit of driving comfort .

[0138] More speci fically, the lever control tower 501 and the electronic control unit 10 are configured in such a way that they can also manage the outcomes of the algorithms that perform a gear pre-selection procedure , and which are already set up in the usual electronic control units that control the dual-clutch gearboxes , to the benefit of speed in changing the gear ratio i f that change is sequential .

[0139] In particular, when the driver attempts to perform a non-sequential gear change , the unit 31 is of particular importance in managing the engagement of the new gear desired by the driver, as it temporarily hinders the rotation of the lever 21 towards the end-of-stroke position at the end of the channels 25 , until the actual engagement of the gear ratio desired by the driver in the dual-clutch gearbox 401 (provided that this gear ratio is compatible with the driving conditions ) .

[0140] In addition, the unit 32 only allows gear changes when the clutch pedal 502 is operated by the driver .

[0141] At the same time , the gear disengagement force and engagement force usually felt with conventional mechanical gearboxes is simulated .

[0142] Other advantages will also be apparent to people skilled in the art , based on the speci fic features described above and / or claimed in the attached claims .

[0143] From the above , it is evident that modi fications can be made to the motor vehicle 1 as described above with reference to the attached figures , and variations produced thereto , without departing from the scope of protection as defined by the attached claims .

[0144] In particular, as mentioned above , the actuating systems , that is , the actuators , for switching the units 31 and 32 , as well as their retention members , could be shaped and arranged di f ferently from the examples provided by way of non-limiting preference .

Claims

CLAIMS1.- A motor vehicle (1) comprising:- an electronic control unit (10) ;- a drive unit (300) having a drive shaft (403) ;- at least two drive wheels (200) ;- a dual-clutch gearbox (401) to transmit motion from the drive shaft (403) to the drive wheels (200) ; the dualclutch gearbox (401) comprising: a) two primary shafts (404, 405) ; b) a secondary shaft (410) ; c) two clutches (407, 408) coaxial to the primary shafts (404, 405) respectively; d) first actuators (409) controlled by the electronic control unit (10) in such a way as to(1) disengage the clutches (407, 408) and then decouple the drive shaft (403) from both the primary shafts (404, 405) , and(2) engage the clutches (407, 408) alternatively to each other to couple the drive shaft (403) selectively to one or other of the primary shafts (404, 405) ; e) a plurality of gearwheels (415b) , which are mounted on the primary and / or secondary shafts (404, 405, 410) in an angularly rotating manner and are associated with respective gear ratios; f) second actuators (416) controlled by the electronic control unit (10) so as to make these gearwheels (415b) angularly fixed to the corresponding primary and secondary shafts (404, 405, 410) and thus engage the corresponding gear ratios;- a control system (500) , which can be operated by the driver to engage a desired gear from a plurality of availablegears, each corresponding to a respective gear ratio, and comprises sensor means (505, 9, 15) configured to detect operations performed by the driver on the control system (500) and send corresponding signals to the electronic control unit (10) ; the electronic control system (10) being configured so as to :- pre-select a gear, within a gear immediately above and a gear immediately below a current gear;- control the second actuators (416) to engage the gear ratio corresponding to the preselected gear in advance of the driver operations on the control system (50) ; characterised by said control system (500) comprising:- a clutch pedal (502) that is movable in response to the driver operations from a rest condition to a disengagement condition;- first sensor means (505) defining part of said sensor means (505, 9, 15) and configured to detect the positions and / or displacement of the clutch pedal (502) ;- a lever control tower (501) comprising: a) an operating lever (21) mounted so as to rotate in response to the driver operations about a first rotation axis (12) , so as to move along a transversal channel (24) and select a gear rank from a plurality of available gear ranks and about a second rotation axis (6) parallel to the transversal channel (24) , so as to be selectively engaged in longitudinal channels (25) extending in opposite directions from the transversal channel (24) and each corresponding to a respective available gear; b) second sensor means (9, 15) defining part of saidsensor means (505, 9, 15) and configured to detect the angular position of the operating lever (21) about the first and second rotation axis (12, 6) ; c) a retention unit (31) comprising(1) a retention member (35; 35a) movable between a rear release position, in which the operating lever (21) is free to rotate, and a forward stop position;(2) third actuator means (34, 39; 34a, 39a) controlled by the electronic control unit (10) to engage and remove a retention action, exerted by the retention member (35; 35a) in the forward stop position so as to hinder the rotation of the operating lever (21) about the second rotation axis (6) from the transversal channel (24) towards an end-of-stroke position in the longitudinal channels (25) ; wherein the electronic control unit (10) is configured to:- determine which desired gear the driver is engaging, based on the signals from the said second sensor means (9, 15) ;- check whether the desired gear determined corresponds to the preselected gear;- control the third actuators (34, 39; 34a, 39a) to remove the retention action exerted by the retention member (35; 35a) if the desired gear determined corresponds to the preselected gear.2.- The motor vehicle according to claim 1, wherein, if the desired gear determined does not correspond to the preselected gear, the electronic control unit (10) is configured to- control the second actuators (416) to engage the gear ratio corresponding to the desired gear determined,- control the third actuators (34, 39; 34a, 39a) to remove the retention action exerted by the retention member (35;35a) with a time delay compared to the case where the desired gear determined corresponds to the preselected gear .3.- The motor vehicle according to any of the previous claims, wherein the retention member (35; 35a) is defined by a rod extending along a straight direction (33; 33a) and is movable along said straight direction (33; 33a) between the forward stop position and the rear release position.4.- The motor vehicle according to claim 3, wherein said straight direction (33; 33a) is radial to the second rotation axis ( 6 ) .5.- The motor vehicle according to any of the previous claims, wherein the third actuators (34, 39; 34a, 39a) comprise :- at least one spring (39; 39a) having a preload that brings the retention member (35; 35a) towards the forward stop position, and- an electric actuator (34; 34a) controlled by the electronic control unit (10) to engage and disengage the retention action .6.- The motor vehicle according to claim 5, wherein said electric actuator (34a) , when electrically powered, exerts a force concordant with a force exerted by said spring (39a) to define said retention action in the rear release position.7.- The motor vehicle according to any of the previous claims wherein the lever control tower (501) further comprises a drum (8) angularly fixed with respect to the operating lever (21) so as to rotate about the second rotation axis (6) together with the operating lever (21) between an intermediate angular position, wherein theoperating lever (21) engages the transversal channel (24) , and two operational angular positions, opposite to each other, wherein the operating lever (21) engages respective longitudinal channels (25) to engage the corresponding gears; and wherein the retention unit (31) comprises a groove (38; 38a) , formed on a side surface of said drum (8) and engaged by the retention member (35; 35a) when both of the following conditions are met:- the drum (8) is arranged in the intermediate angular position, and- the retention member (35; 35a) is arranged in the forward stop position.8.- The motor vehicle according to claim 7, wherein the groove (38a) has a width, along a circumferential direction about the second rotation axis (6) , and / or a shape such as to allow a predefined freedom of rotation from the intermediate angular position towards the operational angular positions, even if the retention member (35a) is arranged in the forward stop position.9.- The motor vehicle according to claim 7 or 8, wherein the side surface of the drum (8) defines a shoulder that holds the retention member (35) in the rear release position against the thrust of a spring (39) when the drum (8) is arranged in the operational angular positions.10.- The motor vehicle according to any one of claims 7 to 9, wherein the retention member (35; 35a) is movable along a straight direction (33; 33a) between the forward stop position and the rear release position, and wherein the groove (38; 38a) is aligned with the retention member (35; 35a) along said straight direction (33; 33a) when the drum (8) is arranged in the intermediate angular position.11.- The motor vehicle according to any one of claims 7 to10, wherein the drum (8) has three seats (30b, 30a, 30c) which are side-by-side with each other along an arc of a circle about the second rotation axis (6) ; and wherein the lever control tower (501) comprises another retention unit (32) configured to selectively, releasably engage said seats (30b, 30a, 30c) when the drum (8) is arranged in the intermediate angular position and in the operational angular positions, respectively.12.- The motor vehicle according to any of the previous claims, wherein the electronic control unit (10) is configured to control an additional retention unit (32) in response to signals from the first sensor means (505) to lock the rotation of the operating lever (21) about the second rotation axis (6) when the clutch pedal (505) is in the rest condition.13.- The motor vehicle according to claim 12, wherein the electronic control unit (10) is configured to control the additional retention unit (32) in response to the signals from the first sensor means (505) to unlock the rotation of the operating lever (21) when the stroke of the clutch pedal (505) exceeds a predefined threshold.14.- The motor vehicle according to any of the previous claims, wherein said electronic control unit (10) is configured so as to:- determine the stroke of the clutch pedal (502) based on signals from the first sensor means (505) ;- control the first actuators (409) in such a way as to transmit, at the clutches (407, 408) , a torque that is inversely proportional to the determined stroke.15.- The motor vehicle according to any of the previous claims, in which the electronic control unit (10) is configured so as to:- check whether the desired gear determined is compatible with driving conditions , and- check whether the desired gear determined corresponds to the preselected gear only i f the desired gear determined is compatible with these driving conditions .

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