FR3043045A1 - METHOD FOR CHECKING A MANUAL ACTUATED GEARBOX INTERACTING WITH A CLUTCH - Google Patents

Abstract

A method of controlling a manually operated gearbox interacting with a clutch, comprising the following steps: - determining (202), while the input shaft of the gearbox is rotated, the speed that would take this gearbox input shaft if a given gearbox gear were engaged, - comparing the speed that this gearbox input shaft would have for this given gear with a threshold speed, - depending on the result of this comparison, act (203) on the clutch and/or the gearbox so as to oppose the engagement of this gear by the user.

Description

Method of controlling a manually operated gearbox interacting with a clutch

The present invention relates to a method of controlling a manual gearbox interacting with a clutch. The invention applies in particular to a simple clutch, that this clutch is normally closed or normally open. The clutch is for example electrically or automatically controlled, such a clutch being commonly called "clutch by wire". The actuation of the gearbox being manual, a user can at any time attempt to engage mistakenly a report not adapted to the speed of the vehicle. The user can for example, while his vehicle is traveling at 130 km / h with the report No. 5 or No. 6 of the gearbox engaged, mistakenly try to engage the report No. 1. Such engagement causes the input shaft of the gearbox to take very high speeds that can damage or even destroy the clutch friction disk (s). The flywheel can then also be rotated by jamming the clutch and may be destroyed by centrifugation.

There is thus a need to reduce the risk of damage to the clutch by applying to the gearbox input shaft too high a speed. The invention aims to meet this need and it achieves, in one of its aspects, using a control method of a manually operated gearbox interacting with a clutch, including the following steps: - determining, while the input shaft of the gearbox is rotated, the speed that would take this gearbox input shaft if a given gearbox ratio was engaged, - compare the speed that this gearbox input shaft would have for this given gear with a threshold speed, - depending on the result of this comparison, act on the clutch and / or the gearbox so as to oppose the engagement of this report by the user.

The above method thus makes it more difficult, or even prevent, the erroneous engagement of a gear ratio that is not adapted to the speed of the vehicle. This ensures that a friction disc of the clutch and / or flywheel will not be centrifuged by too high speeds that would be applied to the gearbox input shaft if the unsuitable ratio was engaged, and as a result that friction disc and / or flywheel will not be damaged or destroyed.

The threshold speed is for example chosen according to the characteristics of the friction disc of the clutch or the flywheel so that all speeds of the gearbox input shaft below this threshold speed are not likely to affect the integrity of this clutch disc or flywheel. The action to prevent the commitment of the report by the user may consist of the application of a pair of halftone on the clutch. The drag torque generated by the clutch can then be sufficient to prevent arming of the synchronizer and therefore the revving of the primary shaft of the gearbox. This also generates a transmission noise to draw the attention of the user on the unsuitability of the report that is about to engage with the current speed of the vehicle. The drag torque is for example added to the torque setpoint from the user or the control system of the clutch when the latter is of the "clutch by wire" type.

The method is not limited to the prevention of the engagement of a single given gearbox non-adapted ratio. The method may thus comprise the step of determining the speed that this gearbox input shaft would have for several gearbox ratios that could be engaged, and then comparing for each of these ratios. the speed that this gearbox input shaft would have with a threshold speed.

Thus, given the speed of the vehicle, we can identify among all possible reports of the gearbox, all those that are unsuitable and whose commitment must therefore be avoided to avoid damaging the friction disc of the clutch or the flywheel, by determining the speed that would take the gearbox input shaft for each of these ratios and comparing the speed thus determined with the same threshold speed.

The method may then comprise the step according to which, depending on the result of the comparison for one of these gear ratios, the clutch and / or the gearbox are acted upon so as to oppose the gearbox. commitment of this ratio of the gearbox.

In all the above, the action on the clutch and / or on the gearbox opposing the engagement of a given unsuitable gear can be controlled when the speed that would have the input shaft of gearbox for this given gear is greater than the threshold speed.

It may result from the determination of the speeds that the gearbox input shaft would take for the different gear ratios that some gear ratios may be more dangerous than others, and the value of the drag torque applied to oppose At the engagement of a gearbox ratio can be different from one report to another. The ratios which correspond to can input shaft speeds slightly above the threshold speed can thus be associated with a drag torque value applied to the clutch to oppose their engagement and this torque value of drag is for example less than the drag torque value applied to oppose gearbox engagement (s) which correspond to gearbox input shaft speeds well in excess of the speed threshold. The drag torque value is for example 5 Nm in the first case while the drag torque value is for example 15 Nm in the second case.

In all of the above, the determination of the speed that the gearbox input shaft would take if a given gear ratio was engaged can be performed while another gearbox ratio is already engaged and the gearbox gearbox is engaged. The input shaft of the gearbox is rotated by the motor via the clutch. In other words, this determination of the speed that would take the gearbox input shaft is before an action on the clutch to change gear is performed.

As a variant, in all the foregoing, the determination of the speed that the gearbox input shaft would take if a given gear ratio was engaged is carried out while no gear ratio is already engaged. . The determination is made according to this variant while the gearbox ratio previously used has been disengaged. According to this variant, it is expected before implementing the method according to the invention that the user has shown his desire to change the gearbox ratio. Still according to this variant, no action on the clutch and / or the gearbox is for example performed as long as the user has not indicated his intention to change the gearbox ratio. No drag torque is for example exerted on the clutch to oppose the commitment of a given report until the other gear ratio has been disengaged.

In all of the above, the threshold speed may be 1000 rpm or 1200 rpm.

In all of the above, the clutch can be electrically or automatically controlled. Such a clutch, also called "clutch by wire", is controlled by means of an actuating system comprising: - an actuating pedal associated with a position sensor, - an actuator arranged to move the clutch between a position engaged and a disengaged position, and - a control unit adapted to develop a control signal of the actuator according to the position of the actuating pedal.

Alternatively, a "clutch by wire" type clutch may be devoid of an actuating pedal, the disengaging action being controlled by the operation of the shifter using the position sensor.

In addition to the foregoing, an audible and / or visual warning may be transmitted to the user when the latter attempts to engage the given box report. This maximizes the chances of attracting the intention of the user that he is about to engage a gearbox ratio that is unsuitable because it may affect the integrity of the friction disk of the clutch. and / or flywheel. The visual warning is for example via a screen of the user interface of the vehicle.

In all of the above, the gearbox may have a grid in which a gearshift member such as a gear lever moves, this gate comprising: - rank zones in which the change gear moves report to engage a report, the ends of each rank zone each corresponding to a position of the gear change member for which a gear ratio is engaged, and - selection areas in which the gear member moves. change of gear to move from one rank zone to another, a neutral zone can be defined for each transmission ratio, this neutral zone being the portion of the rank zone associated with this ratio which extends from the joining a selection zone to the location of this rank zone which, when occupied by the gearshift member, corresponds to a position where the corresponding gear is st completely disengaged.

Each row area is for example rectilinear. The location of the rank zone for which the gear ratio is completely disengaged corresponds to the synchronizer arming threshold for this gear ratio. This location of the rank zone delimiting one end of the neutral zone may have been previously learned by the control system of the gearbox and the clutch.

According to the method, a drag torque of a first value can be applied to the clutch when the gearshift member is in the neutral zone of a given gear not adapted to the engagement of which one is opposed . As already mentioned, this drag torque makes it possible to attract the attention of the user before the latter engages the gearbox report associated with the neutral zone in which the gearshift member is located.

A drag torque of a second value greater than the first value may be applied to the clutch to oppose the engagement of a gear ratio when the gearshift member moves into the gear area. associated with this report beyond the neutral zone associated with this report and towards the end of this rank zone which corresponds to the commitment of this report. This thus greatly reduces the possibilities of engagement of this transmission ratio by the user.

As already mentioned, when a gear ratio is engaged, no drag torque opposing the displacement of the shift member to disengage this ratio is preferably applied to the clutch. This ensures that the user can disengage the current report. The invention further relates, in another aspect, to a control system for implementing the method as described above. The invention will be better understood on reading the following description of nonlimiting examples of implementation thereof and on examining the appended drawing in which: FIG. 1 schematically represents an example in which the invention can be implemented; FIG. 2 represents an example of a gearbox grid in which a gearshift member can move; FIG. 3 represents in the form of block diagrams a control system for implementing an exemplary control method according to the invention, and - Figure 4 shows some steps of an exemplary control method according to the invention.

FIG. 1 shows schematically an example of a vehicle in which the method according to the invention can be implemented.

The motor vehicle, shown in this figure, comprises a combustion engine 1 whose output shaft or crankshaft is connected to an input shaft 3 of a gearbox 2 via a clutch 4. In a conventional manner, the transmission torque between the crankshaft and the input shaft 3 of the gearbox 2 is ensured when the clutch 4 is in an engaged position and is interrupted when the clutch 4 is in a disengaged position.

According to one embodiment, the clutch 4 comprises a reaction plate integral in rotation with the crankshaft of the combustion engine 1, a friction disk equipped with a grooved means cooperating with splines formed on the input shaft of the engine. gearbox and a clutch mechanism. The clutch mechanism comprises a movable pressure plate, a cover fixed on the reaction plate, and a diaphragm mounted, on the one hand, tilting against the bottom of the lid, and on the other hand, bearing against a plate of pressure. The diaphragm biases the pressure plate towards the reaction plate.

An actuating member, such as a clutch abutment, is able to act on the diaphragm to tilt it and thereby move the pressure plate between an engaged position, in which the friction disc is pinched between the plate pressure and the reaction plate to allow a transmission of the engine torque of the crankshaft to the input shaft of the gearbox, and a disengaged potion in which the pressure plate is moved away from the friction disc.

The vehicle here comprises a "clutch by wire" type clutch, being equipped with a clutch actuation system comprising in the example described a pedal 19 for actuating the clutch, an associated position sensor 20 to the pedal 19 and able to deliver a signal representative of the position of the pedal 19 and an actuator 14. The actuator 14 is connected to a battery 15 of the vehicle via a power supply network 16 and to a control unit. the clutch 17, via a multiplexing bus 18.

The position sensor 20 is for example a contact sensor comprising a movable rod in contact with the pedal 19. However, the position sensor 20 may be a proximity sensor, without contact. The position sensor 20 can be fixed on the chassis of the vehicle and thus provides a signal representative of the absolute position of the pedal 19, that is to say, the position of the pedal relative to the chassis. However, the position sensor 20 can also be arranged to deliver a signal representative of the relative position of the pedal 19, that is to say the position of the pedal 19 relative to a support member pivotally mounted on the chassis.

Still with reference to FIG. 1, it will be observed that the gearbox 2 comprises an output shaft 5, parallel to the input shaft 3, which is equipped with idle gears 6 cooperating with gear gears 7 carried by the gearbox. input shaft 3. The output shaft 5 carries synchronizers 8 for securing the idle gears 6 to the output shaft 5, so as to engage a transmission ratio between the input shaft 3 and the output shaft 5 of the gearbox. The output shaft 5 cooperates with a differential input gear 10 in order to transmit the torque to the wheels 9a, 9b. A gearshift 20 forms a shifting member of the gearbox 2 and makes it possible to select and manually engage the synchronizers 8. The shifter 20 is associated with a position sensor 21 making it possible to detect the selected gear as well as a change of report.

Moreover, the vehicle is equipped with numerous sensors, such as a sensor 11 for measuring the engine speed, a sensor 12 for measuring the speed of rotation of the input shaft 3 of the gearbox 2 and / or a sensor 13 for measuring the speed of rotation of the output shaft 5 of the gearbox 2.

The motor vehicle further comprises a steering wheel 22, a brake pedal 23 associated with a sensor 24 adapted to deliver a signal representative of the position of the brake pedal, a brake control module of the ABS 28 type, a pedal 25 of accelerator associated with a position sensor 26 of the accelerator pedal, a parking brake 27, a parking brake management module 29 and an automatic parking assistance module 30.

In the embodiment shown, the vehicle is furthermore equipped with a selection means 31 enabling in particular the driver to choose whether he wishes to benefit from one, more or all of the proposed steering modes. The selection means 31 may be a switch disposed on the dashboard and / or a configuration panel comprising a menu accessible via an electronic interface of the onboard control and allowing a selection of options at the request of the driver. In one embodiment, the options of the control modes are also configurable via an application capable of communicating with a dedicated application of a remote telematic / telephone device, of the "Smartphone" type.

FIG. 2 shows an example of gate 40 of gearbox 2. In the example considered, gearbox 2 comprises five gear ratios numbered from 1 to 5 and a reverse gear shown opposite the gear ratio. # 5. A higher number of gears, for example six gear ratios and a reverse gear, is of course possible.

The gate 40 defines a plurality of paths for the displacement of the shifter 20. The set of displacement paths for this lever is formed by: - rank zones 41 in which the shifter 20 moves to engage the shifter. report No. 1 or the report No. j of the gearbox 2, and - selection areas 42, in which the gear lever 20 moves between two areas of rank41ij.

As can be seen in FIG. 2, each rank zone 41 y and each selection zone 42 is rectilinear here.

It can also be seen in FIG. 2 that each end 43, respectively 43j, of a rank zone 41 corresponds to a gear ratio i, j respectively, engaged when the gear lever 20 is positioned at this end of the gearbox. the area of rank 41 y.

It can still be seen in FIG. 2 that each transmission ratio i or j is associated with a neutral zone 44; or 44j, this neutral zone being the portion of the rank zone 41y extending from the junction with a selection zone 42 to the location 45j or 45j of this rank zone 41 y which, when occupied by the shifter 20, corresponds to a total disengagement of this ratio i or j. The end 45j of the neutral zone 44; the closest to the end 43; the row path 41 corresponds here to the arming threshold of the synchronizer 8 for gear ratio i considered. As represented in FIG. 2, within the same rank zone 41y, the neutral zone 44; and the neutral zone 44j extend continuously in the extension of one another.

The method according to the invention makes it possible to attract the attention of the user of the vehicle when he is preparing to engage a gear ratio that is not suitable because it may affect the integrity of the friction disk of the vehicle. clutch 4 and / or flywheel integrity, as will now be described.

FIG. 3 represents a block diagram of a control system 100 making it possible to implement the method according to the invention.

A first input block 101 receives three inputs which are here: the current speed Ei of the vehicle, and for each gear ratio different from that which is engaged or which has just been disengaged, the gear ratio E2. and the radius E3 of the wheel associated with this ratio.

Thus, for each gearbox ratio different from that which is engaged or which has just been engaged, it is possible to determine the speed that the box input shaft would have if the user engaged one of these gearboxes. gearbox ratios by acting on the gear lever 20.

At the output of this block 101, the different speeds that the transmission input shaft would take for the other gear ratios are transmitted to a block 102.

This information is compared by the block 102 with a threshold speed which is a function of the friction disk of the clutch 4. The threshold speed is for example the speed from which the friction disc is subjected to a centrifugal force risking to damage it. This threshold speed is for example equal to 1000 rpm or 1200 rpm

For each of the box ratios that can be engaged, the block 102 thus determines whether the box input shaft speed resulting from the work done by the block 101 is greater than the threshold speed. When it is the case for a given report, this report is recorded as not adapted and as not to be engaged by the user via the shifter 20.

At the output of the block 102, a list of unsuitable gear ratios is transmitted to a block 103 in charge of the application of a drag torque on the clutch 4.

The block 103 also receives two inputs E4 and E5 which are respectively the selection zone 42 and the rank zone 41 y with which the gear lever 20 cooperates, so as to determine the gear ratio that the user has. ready to engage using the shift lever 20.

The block 103 also receives as input the output of a training block 105 of the gate 40. This block 105 receives as respective inputs E6 to E9: - the same quantities E6 and E7 as those of the inputs E4 and E5, - the speed of the input shaft of the gearbox 2, and - the speed of the vehicle.

The block 105 provides, on the basis of these inputs E6 to E9 the engagement thresholds box reports.

Based on these different information received, the block 103 thus calculates, for the unsuitable gear ratio that the user primed to engage, a drag torque setpoint to be applied to the clutch 4 for the neutral zone 44; associated with this report i not suitable.

This drag torque setpoint is then added by a block 106 to the torque setpoint resulting from the action of the user to conventionally engage this box ratio and / or the automatic control of the clutch 4.

The method according to the invention implements for example the steps shown in FIG.

According to this figure, a step 200, for example carried out by the block 103 of FIG. 3, consists in applying a zero drag torque set point for all the ratios if the current speed of the box input shaft is less than the threshold speed. Step 201 corresponds to a control, for example carried out by block 103 of FIG. 3 of the position of the shifter 20. As long as this shifter is in a position corresponding to the engagement of a report associated with a box input shaft speed below the threshold speed, nothing happens. Step 202 is triggered when the report that was engaged in step 201 is disengaged. This step 202 is carried out by blocks 102 and 103 and consists of: calculating the different speeds of the gearbox input shaft that would be reached for the other engageable ratios, and determining the gear ratios that are not adapted to the commitment of which we must oppose. At the end of this step 202, the block 103 can, during a step 203, determine two distinct values of torque setpoint, so as to prevent the engagement of the unsuitable ratio (s): a first value of drag torque setpoint is for example generated, so as to be applied to the clutch for each neutral zone 44; associated with an unsuitable gear ratio, and - a second drag torque setpoint value greater than the first value is also generated, so as to be applied to the clutch when the gear lever 20 moves in the zone rank 41 associated with this ratio beyond the neutral zone 44; associated with this report, this displacement of the gear lever 20 to engage this report.

The first drag torque setpoint value is for example 5 Nm while the second value is for example 15 Nm.

For box ratios that are not considered unsuitable after step 202, the drag torque setpoint remains, for example, zero. Step 204 corresponds to the attempt by the user to engage an unsuitable ratio, despite the existence of the drag couples resulting from step 203. This step is then followed by a step 205 which corresponds in the example described in the sending to the user of an audible and / or visual warning to draw his attention to the prohibition of the continuation of his attempt to engage this ratio gearbox. A pictogram may for example be displayed on a screen of the electronic interface of the control board during this step 205. The invention is not limited to the example just described.

In step 203, the block 103 can determine different drag torque setpoint values depending on the gear ratios. Some reports are, for example, more critical than others and the different drag torque setpoint values will then be applied.

For example, if it turns out that we are driving at 130 km / h with report n ° 5 that the commitment of the report n ° 1 is more critical than the commitment of the report n ° 4, the first ones and second drag torque setpoint values of step 203 associated with the ratio no. 1 will be respectively higher than the first and second halftone setpoint values associated with the ratio # 4.

Furthermore, although the method according to the invention has been described with reference to a "clutch by wire" clutch, the invention is not limited thereto.

Claims (12)

claims A method of controlling a manually operated gearbox interacting with a clutch, comprising the steps of: determining (202), while the input shaft of the gearbox is rotated, the speed what would this gearbox input shaft take if a given gearbox ratio was engaged, - compare the speed that this gearbox input shaft would have for that gear given with a threshold speed, - in depending on the result of this comparison, act (203) on the clutch and / or the gearbox so as to oppose the engagement of this report by the user. 2. The method of claim 1, wherein a drag torque is applied (203) on the clutch to oppose the engagement of this report by the user. 3. A method according to claim 1 or 2, wherein (202) is determined the speed that this gearbox input shaft would have for several gearbox ratios that could be engaged, and in which one compares for each of these reports the speed of this gearbox input shaft with a threshold speed. 4. The method of claim 3, wherein according to the result of the comparison for one of these gear ratios, it acts (203) on the clutch and / or the gearbox so as to oppose the commitment of this ratio of the gearbox. 5. The method as claimed in claim 4, in which a drag torque of different value of a transmission ratio is applied to the other, so as to oppose the engagement of these gear ratios. speeds. A method as claimed in any one of the preceding claims, wherein the determination of the speed that the transmission input shaft would take if a given gear ratio was engaged is performed while another gear box ratio speeds is already engaged and that the input shaft of the gearbox is rotated by the motor via the clutch. The method of any one of claims 1 to 5, wherein the determination of the speed that the gearbox input shaft would take if a given gear ratio was engaged is performed while no gear ratio. gear is already engaged. 8. Method according to any one of the preceding claims, wherein the clutch is electrically or automatically controlled. A method according to any one of the preceding claims, wherein an audible and / or visual warning is transmitted (205) to the user when the latter attempts to engage the given gearbox report. 10. A method according to any one of the preceding claims, wherein the gearbox has a grid (40) in which moves a gear change member (20), the gate (40) comprising: - rank zones (41 y) in which the shift member (20) moves to engage a gear, the ends (43; 43j) of each rank zone (41 y) each corresponding to a position of the gear member. gear change (20) for which a gear ratio (i, j) is engaged, and - selection zones (42) in which the gear shift member (20) moves to pass from a gear box. rank to another, in which method is defined for each box ratio a neutral zone (44j, 44j) as being the portion of the rank zone (41 y) associated with this ratio (i, j) extending from the joining a selection zone (42) to the location (45; 45j) of this rank zone (41 y) which, when occupied by the gear change member (20), corresponds to a position where the corresponding gear (i, j) is completely disengaged, in which process a drag torque of a first value is applied to the clutch when the gearshift member (20) is in the neutral zone (44; 44j) of a given ratio (i, j) to which engagement is opposed. The method of claim 10, wherein a drag torque of a second value greater than the first value is applied to the clutch to oppose engagement of a given gear ratio (i, j). when the gearshift member (20) moves in the rank zone (41 y) associated with this given ratio (i, j) beyond the neutral zone (44; 44j) associated with this ratio ( i, j) towards the end (43 ;, 43j) of this rank zone (41 y) corresponding to the engagement of this ratio (i, j). The method according to claim 10 or 11, wherein when a gear ratio is engaged, no drag torque opposing the displacement of the shift member (20) to disengage this gear is applied to the clutch.