FR3004772A1 - POWERTRAIN AND METHOD OF CONTROLLING THE GEARBOX FOR PROCESSING ACYCLISMS - Google Patents

Abstract

The invention relates to a powertrain comprising a gearbox (1) having at least two clutches (2.1, 2.2). For the treatment of motor acyclisms, the control method of the gearbox according to the invention makes it possible to exploit the rotational inertia of the primary shaft of the gearbox (API or AP2) having no gear ratio. speed engaged to improve the filtering of motor acyclisms by closing the clutch (2.1 or 2.2) corresponding. The invention applies to gearboxes of powertrains having several clutches.

Description

BACKGROUND OF THE INVENTION The field of the invention relates to a motor vehicle powertrain and a transmission control method for filtering engine acyclic processing. BACKGROUND OF THE INVENTION Powertrains with a double clutch gearbox are known. These gearboxes comprise two concentric primary rotation shafts, each coupled on the one hand to the crankshaft of the engine at the input of the gearbox by a clean clutch, and on the other hand to sets of idle / fixed gears corresponding to gear ratios. Thus, a first rotation shaft is dedicated to even gear ratios while the second rotation shaft is dedicated to odd gear ratios. Synchronizers select the idle gears positioned on secondary shafts allowing to engage and disengage a gear ratio. The advantage of such a gearbox is the speed of passage of report without breaking torque thanks to the possibility of selecting in advance the next gear ratio before switching on the speed change process.

More precisely, when rolling when the gearbox is configured with a gear ratio linked to one of the two primary shafts, the clutch of this primary shaft is closed. Then, the second clutch associated with the second primary shaft is open, and this second primary shaft is not in a friction situation for preselecting a gear ratio of the second primary shaft. The preselection calculations are carried out by means of an on-board computer which, according to the current situation, evaluates the preselected speed ratio of the primary shaft whose clutch is not in a friction situation. During the operation of a powertrain creeping phenomena in English, buzzing, shot and grazing can occur and bring inconvenience to driving. The powertrain gearbox may also include a damping flywheel for filtering vibrations during coupling when the clutches are closed. For example, a dual damping flywheel includes a primary portion and a secondary portion. The primary part is the rigid part rigidly connected to the crankshaft to the filter spring of the double damping flywheel and the secondary part is the rigid part which rigidly connects the filtering spring to the primary shaft of the gearbox. The chatter is a geometric defect on the coupling member (lack of coplanarity of the friction and the clutch plate) or an offset engine / gearbox that generate vibrations, only during the closing phase of the clutch. The shot is the sound of the crazy gears of the gearbox that clash under the excitement of motor acyclism. To make it disappear, it is possible to improve the filtration of the coupling member of the transmission by increasing the secondary inertia, reducing the stiffness of the coupling or decreasing motor acyclism by limiting its maximum torque. The "creeping" is the sound of the contacts of the driven / leading sprockets under the excitement of motor acyclism. To make it disappear, it is necessary to improve the filtration of the coupling member by increasing the secondary inertia or by reducing the stiffness of the coupling. The applicant has filed the French patent application with the publication number FR2977647 for the treatment of grazing problems during takeoff of the vehicle. The solution described in this patent consists in simultaneously engaging the first and second gear ratios and managing the takeoff by acting on the openings and closures of the two clutches when the level of acyclism exceeds a critical threshold. However, this solution does not make it possible to deal with the noise problems of the contacts, buzzing and shots which occur during the running, ie during low load rolling for the noise of the contacts and while driving under load for the engine. shotgun shot and for zoom. Currently, to increase filtering of the acyclism of the coupling member under the phenomenon of shot and noise of gearbox and buzzing felt in the cabin, one solution is to add inertia on the part secondary coupling members, that is to say the secondary part of the double damping flywheel. However, too much secondary inertia of the coupling members causes other problems. The more there is inertia on the coupling member, the more the start performance is degraded, as well as the consumption and brio of the engine, the greater the cost of the coupling member is important and the mass of the body coupling is important.

The object of the invention proposes a solution to overcome these problems mainly when the motor acyclism becomes critical, and mainly under full load of the engine. More specifically, the invention relates to a method of controlling a gearbox of a powertrain for treating a phenomenon of acyclism on an input shaft of the gearbox, said gearbox comprising a first gearbox. and a second clutch adapted respectively at their closure to friction a first and second primary shafts with the input shaft, each of the primary shafts comprising at least one gear ratio gear can be engaged and disengaged. According to the invention, the method comprises the following successive steps when the clutch of the first primary shaft is closed for its rotation, the latter being configured with a gear gear gear engaged, and the clutch of the second main shaft is open: a step of detecting a critical operation of the gearbox, the critical operation being defined by a critical acyclism of the input shaft of the gearbox; a step of closing the clutch of the gearbox; second primary shaft as long as the operation is critical, the second primary shaft being configured without engagement of the gear ratio gear during closing of the clutch, a step of opening the clutch of the second input shaft after the detection of the end of critical operation. Alternatively, when the gear gear of the second shaft gear ratio is pre-engaged, the method comprises a step of disengaging the gear ratio gear of the second main shaft before the closing step of the second clutch. Preferably, the gearbox comprising an idler gear carried by a secondary shaft and driven by the gear of the pre-engaged gear ratio of the second primary shaft and a synchronizer carried by the secondary shaft can move between a clutched position and a position decoupled with the idler gear, the disengaging step comprises a step of moving the synchronizer from the position clutched to the position decoupled. In a variant, the critical operation detection step is performed on the basis of a measurement of a powerplant engine speed compared with a critical operation map of the engine.

Alternatively, the critical operation detection step is performed from a measurement of the rotational speed of the input shaft compared to a critical acyclic threshold. The invention also relates to a powertrain comprising a gearbox comprising at least two clutches. According to the invention, it comprises a control member adapted to implement the control method according to any of the variants described above. Thus, thanks to the invention it is possible to reduce the secondary inertia of the dual flywheel damper powertrain. This makes it possible to improve start-up performance, reduce engine consumption, improve the engine's brilliance, reduce the cost of coupling and the mass of the coupling by reducing the material required.

Other features and advantages of the present invention will appear more clearly on reading the following detailed description of embodiments of the invention given as non-limiting examples and illustrated by the appended drawings, in which: FIG. 1 represents a diagram of an example of a double-clutch gearbox that can implement the method according to the invention. - Figure 2.1 shows the configuration of the gearbox during a rolling situation with the gear ratio second engaged and the gear ratio third preselected. - Figure 2.2 shows the configuration of the gearbox during the execution of the method according to the invention when adding the rotary inertia. FIG. 3 represents a diagram of the operations of the method according to the invention. FIG. 1 represents an example of a double-clutch gearbox 1 comprising a first and second primary shafts AP1 and AP2 associated respectively with a first and second clutch 2.1 and 2.2 forming a double clutch 2. The input shaft 30 of FIG. clutch 2 is in friction with the primary shafts when their respective clutch is closed.

The primary trees AP1 and AP2 are concentric. The gearbox 1 also comprises two secondary shafts AS1 and AS2 connected to a differential (not shown) itself connected to the wheels of the vehicle. Pairs of gears forming gear ratios are installed between the primary shafts AP1, AP2 and the secondary shafts AS1, AS2. These pairs of pinions are formed by an idler gear mounted on one of the secondary shafts AS1, AS2 meshing with a pinion connected in rotation with one of the primary shafts AP1, AP2, the pinion of the primary shaft driving the pinion of the pinion. secondary tree.

More precisely, the gear ratios are formed by the following pinion pairs: the pinion mounted idly on the secondary shaft AS1 and the pinion 11 connected in rotation with the primary shaft AP1 forms the first gear ratio; pinion 4 mounted loosely on the secondary shaft AS1 and the pinion 5 connected in rotation with the primary shaft AP2 form the second gear ratio, - the pinion 8 mounted loosely on the secondary shaft AS1 and the pinion 9 linked in rotation with the primary shaft AP1 form the third gear ratio, - the pinion 6 mounted loosely on the secondary shaft AS1 and the pinion 7 connected in rotation with the primary shaft AP2 form the fourth gear ratio, - the pinion 13 mounted crazy on the secondary shaft AS2 and the pinion 12 connected in rotation with the primary shaft AP1 form the fifth gear ratio, - the pinion 14 mounted idly on the secondary shaft AS2 and the pinion 7 connected in rotation with the primary shaft AP2 form the sixth vi report the intermediate gear 15 mounted idler on the secondary shaft AS2 and driven by the idler gear 4 mounted on the secondary shaft AS1 and the pinion 5 connected in rotation with the primary shaft AP2 form the reverse gear. In a variant, the gearbox may comprise a number of lower or higher gear ratios. The configuration of the gear sets chosen to form the gear ratios may also vary. For example, the invention can also be applied to a gearbox with seven speed ratios as described in the French patent application FR2977647.

The gearbox also includes synchronizers 3.1-3.4 each associated with gear ratios. These synchronizers can pass, by displacement in translation along the shaft on which they are installed, a clutched position in which the synchronizer cooperates with the idler gear to link in rotation the idler gear with the synchronizer shaft at a decoupled position in which the synchronizer is released from the idler gear so that the idler gear is free to rotate on the shaft. In this case, the synchronizer 3.1 is installed between the second and fourth report. Synchronizer 3.2 is installed between the first and third gear. Synchronizer 3.3 is installed between the sixth and reverse gear. The 3.4 synchronizer is installed with the fifth gear.

The primary shaft AP1 and the primary shaft AP2 are connected to the input shaft 30 of the double clutch 2 respectively by the clutch 2.1 and the clutch 2.2. When driving when an odd speed ratio is engaged by the appropriate synchronizer on the secondary shaft, the clutch 2.1 of the primary shaft AP1 is closed. The clutch 2.2 of the primary shaft AP2 is then open, an even speed ratio is preferably preselected by the appropriate synchronizer on the secondary shaft. The transition from an odd speed ratio to a pair gear ratio is performed by opening the clutch 2.1 and closing the clutch 2.2 simultaneously. The transition from an even speed to an odd speed is carried out analogously. Furthermore, when an odd speed ratio is engaged, the preselection of a speed ratio may not be effective depending on the current situation and the configuration of the control means of the gearbox.

The powertrain comprises a control member (not shown in the figures) of the gearbox 1, in particular for the management of the gearshifts, control of the synchronizers 3.1-3.4, clutches 2.1, 2.2 and for the calculations of the functions and data necessary for the management of the gearbox and the implementation of the control method according to the invention. Integrated circuits centralized powertrain or dedicated to the gearbox 1 implement these control functions of the gearbox 1.

As previously described when a clutch 2.1 or 2.2 is closed the input input shaft AP1 or AP2 is in friction with the input shaft 30. The friction of a primary shaft AP1, AP2 implies that the Inertia of rotation of the primary shaft is added to the inertia of the input shaft 30. Thanks to the invention it is possible to exploit this inertia to deal with phenomena of shot, noise and buzzing during taxiing. of the vehicle. The powertrain comprises means for detecting a critical operation generating phenomena of shot, noise and buzzing during the running of the vehicle. The critical operation corresponds to a critical level of acyclism on the input shaft 30 of the gearbox. The detection can be carried out for example by measuring the acyclism on the input shaft 30 of the gearbox or by the detection of a critical operation by means of pre-established maps of operation of the powertrain. When the powertrain enters such an operating situation, the control method of the gearbox according to the invention is implemented for its resolution. Critical thresholds of acyclisms can be determined in order to trigger the control process of the gearbox to improve the filtering of acyclisms. For example, a critical threshold of acyclism can be defined to maintain an acyclism on the input shaft of the gearbox less than about 400 rad / s2. Detection functions can be performed by computers (integrated circuits for example) of the control unit of the powertrain. Figure 2.1 shows a diagram of the configuration of the gearbox 1 in a first assumption of driving situation with the second engaged ratio and the third preselected ratio. This hypothesis corresponds to the step E13 of FIG. 3. In this configuration, the synchronizer 3.1 in the interconnection position is engaged with the idler gear 4, the clutch 2.2 is closed and the primary shaft AP2 is in friction with the input shaft 30, the synchronizer 3.2 in the dog clutch position is engaged with the idler gear 8, the clutch 2.1 is open and the primary shaft AP1 is not in friction with the input shaft 30. In a second hypothesis of rolling situation (not shown), the third gear ratio may not be preselected, that is to say that the synchronizer 3.2 in decoupling position is not engaged with the idler 8. This assumption corresponds to the step Eh 1 of Figure 3, or also to step E14 following the disengagement of the preselection of the primary shaft AP1. Figure 3 shows the control method of the gearbox for the resolution of problems of acyclism.

In the assumption of rolling situation E13 and following a detection event of a critical level of acyclism D1 on the input shaft 30 of gearbox 1, the control member of the gearbox checks if the disengagement of a preselection of the speed ratio is authorized during the verification step D2. If the disengagement of the preselected speed ratio is authorized, the control member of the gearbox 1 controls the withdrawal of the preselection of the gear ratio not engaged during a step E14, that is to say the disengagement of the synchronizer 3.2 of the idler gear 8 of the secondary shaft AS1 corresponding to the third gear. Then, the control member orders the closing of the clutch 2.1 during a step E15, the primary shaft AP1 having no gear ratio engaged. Figure 2.2 shows the configuration of the gearbox 1 in step E15. This configuration is maintained as long as the level of acyclism is considered critical. If the driving situation does not allow the control member to control the disengagement of the preselection of the gear ratio, the control process is suspended and the clutch 2.1 of the gearbox remains open. At the beginning of the process, if the hypothesis of the rolling situation corresponds to the situation of the step Eh, as previously described, and following a detection event of a critical acyclism level D1 on the tree of input 30 of the speed box 1, the control member orders the closing of the clutch 2.1 during a step E12, the primary shaft AP1 having no gear ratio engaged. Figure 2.2 shows the configuration of the gearbox 1 in step E12. This configuration is maintained as long as the level of acyclism is considered critical. When the primary shaft AP1 is in friction with the input shaft of the gearbox, the rotational inertia of the primary shaft AP1 for which the gear ratio is not engaged is added to the inertia of the gearbox. the input shaft 30 of the gearbox 1. This addition of inertia improves the filtering of the double damping flywheel 40 for reducing the acyclisms of the powertrain engine. This addition of rotary inertia can be added when it is necessary by simply closing one of the two clutches of the gearbox. It is thus possible to undersize the parts constituting the double damping flywheel, in particular the secondary part of the double damping flywheel, by exploiting the unused inertia of the double clutch gearbox. The invention makes it possible to reduce the mass of the torque member, and consequently its cost of production, the consumption and the brilliance of the vehicle.

For example, on this powertrain architecture closure of the clutch allows to obtain about 10g.m2 of inertia with the primary shaft having no gear engaged. This allows to reduce the secondary inertia of 10g.m2 compared to the need for secondary inertia of the double damping flywheel for filtering acyclisms. If a detection event D3 of the output of the critical operating situation of the powertrain appears, then the control member of the gearbox controls the opening of the clutch 2.1 in a step E16, ending the addition rotary inertia from the primary shaft AP1. Optionally, the preselection of the gear ratio initially engaged or any other gear ratio is allowed. In this case, a synchronizer 3.1 or 3.4 is engaged in an idle gear. The powertrain thus returns to the initial configuration before closing the clutch 2.1. The amount of rotational inertia is thus adapted for filtering acyclisms throughout the operation of the powertrain. As a variant, the method also applies to the other possible initial assumptions of speed ratio configuration, for example for which the primary shaft 2.1 is in friction with an odd gear ratio engaged and the primary shaft 2.2 is not in friction with a pair gear ratio engaged or not. Then the method according to the invention proceeds in a similar manner to the steps described in FIG. 3. The invention applies to motor vehicle powertrains comprising a gearbox comprising at least two clutches and making it possible to add inertia. rotary to the input shaft of the gearbox from a primary shaft having no gear ratio engaged.

Claims (6)

REVENDICATIONS1. A method of controlling a gearbox (1) of a powertrain for treating a phenomenon of acyclism on an input shaft (30) of the gearbox, said gearbox comprising a first and a second gearbox clutches (2.2, 2.1) respectively able when they are closed to frictionally friction between a first and second primary shafts (AP2, AP1) with the input shaft (30), each of the primary shafts comprising at least one gear gear (9, 11, 5, 7) which can be engaged and disengaged, the method being characterized in that it comprises the following successive steps when the clutch (2.2) of the first primary shaft (AP2) is closed for its rotation, the latter being configured with a gear gear gear engaged (5), and the clutch (2.1) of the second primary shaft (AP1) is open: - A step of detection (D1) of a critical operation of the gearbox ( 1), the critical operation being defined by a critical acyclism of the input shaft (30) of the gearbox (1), - a closing step (E12; E15) of the clutch (2.1) of the second primary shaft (AP1) as long as the operation is critical, the second primary shaft (AP1) etan t configures without commitment of the speed ratio pinion (9) during closing of the clutch, - a step of opening (E16) of the clutch (2.1) of the second primary shaft (AP1) after the detection (D3 ) of the end of critical operation. A method according to claim 1 comprising, when the gear gear (9) of the second shaft (AP1) is pre-engaged, a step of disengaging (E14) the gear gear (9) from the second shaft. primary (AP1) before the closing step (E15) of the second clutch (2.1). 3. Method according to claim 2, the gearbox comprising a idler gear (8) carried by a secondary shaft (AS1) and driven by the pinion (9) of the pre-engaged speed ratio of the second main shaft (AP1). and a synchronizer (3.2) carried by the secondary shaft (AS1) movable between a clutched position and a decoupled position with the idler gear (8), wherein the disengaging step (E14) comprises a step movement of the synchronizer (3.2) from the clutched position to the decoupled position. 4. A method according to any one of the preceding claims, wherein the step (D2) for detecting the critical operation is operated from a measurement of a powerplant engine speed compared with a critical operating mapping of the engine. engine. 5. A method according to any one of claims 1 to 3, wherein the step (D2) of detecting the critical operation is operated from a measurement of the rotational speed of the input shaft (30). compared to a critical threshold of acyclism. 6. Powertrain comprising a gearbox (1) comprising at least two clutches (2.1, 2.2), characterized in that it comprises a control member adapted to implement the control method according to any one of Claims 1 to 5. 30