EP3080488A1

EP3080488A1 - Method and device for controlling the preselection of a gear ratio in a dual-clutch gearbox, in order to limit the noise made

Info

Publication number: EP3080488A1
Application number: EP14806036.1A
Authority: EP
Inventors: Olivier BALENGHIEN; Alexandre Deschamps
Original assignee: Peugeot Citroen Automobiles SA
Current assignee: PSA Automobiles SA
Priority date: 2013-12-11
Filing date: 2014-11-07
Publication date: 2016-10-19
Also published as: FR3014522A1; WO2015086932A1; CN105980746A; CN105980746B; FR3014522B1

Abstract

A method for controlling the preselection, in a vehicle, of a gear ratio of a dual-clutch gearbox comprising a sliding gear, rotating as one with a secondary shaft while at the same time being capable of translational movement and comprising a dog clutch and a synchronizer which can be coupled to an idling pinion mounted to rotate freely on the secondary shaft. This method comprises a first step (30) in which a minimum force is applied to the sliding gear to cause the synchronizer a translational movement and bring about synchronizing coupling with the idling pinion giving rise to a noise below a first threshold, and a second step (30) in which a force higher than a second threshold is applied to the sliding gear in order to force the dog clutch to offset the synchronizer angularly, then the dog clutch is made to effect a translational movement at a predefined minimum speed in order to bring about coupling of the latter to the idling pinion giving rise to a noise below the first threshold.

Description

METHOD AND APPARATUS FOR CHECKING THE PRESELECTION OF A REPORT OF A DOUBLE CLUTCH GEARBOX TO LIMIT INDUCED NOISE

The invention relates to vehicles comprising a heat engine coupled to a dual clutch gearbox (or DCT), and more precisely the control of the preselection of a gear in such a gearbox.

As is known to those skilled in the art, gearboxes of the aforementioned type advantageously make it possible to simultaneously engage their two primary shafts on different ratios, in order to allow gear shifts under torque, that is to say without interrupting the acceleration of the vehicle. A very fast gear change without breaking torque is done in two steps. In a first step, when an odd or even ratio is engaged in the gearbox, the computer controlling the gearbox anticipates the engagement of the next gear by preselecting an odd or even gear. This is called the "screening pass". In a second step, when certain conditions are met, the computer controls the engagement of the next report by causing the closing of the clutch which is associated with the preselected ratio and opening the other clutch associated with the report being engaged.

The preselection of the next report can be triggered almost any time by the computer controlling the gearbox, so it may happen that it occurs at a time when the behavior of the driver (especially on the brake pedal or accelerator) shows that he does not want to significantly modify the current dynamics of the vehicle. In this situation, the driver can then be surprised by the noise that is induced by the preselection and in particular by coupling the synchronizer to the idler gear to preselect and then by coupling the dog to the same idler. The lower the speed of the vehicle, the lower the general noise induced by the vehicle, therefore the lower the masking noise, and therefore the noise of the preselection is audible inside the vehicle. Therefore, Preselections of reports associated with low speeds are usually those that are most often heard.

In the presence of such noises during "inaction" phases, the driver may be concerned that the transmission may be malfunctioning, and thus may be tempted to return his vehicle to his dealer for examination, which makes him waste time and possibly money.

To prevent such noises disturb the driver, it is possible to add a layer of sound-absorbing material under the hood of the vehicle, but) this increases not only the cost of manufacturing this vehicle but also the weight of the latter, and therefore its energy consumption.

The invention therefore aims to improve the situation.

It proposes in particular for this purpose a method for allowing the control of the preselection, in a vehicle, of a gear ratio of a double-clutch gearbox comprising at least one passenger, secured in rotation to a secondary shaft while being able to translate on the latter, and comprising at least one dog, adapted to be translated to be coupled to a idler gear mounted free rotation on the secondary shaft, and at least one synchronizer adapted to be translated to be coupled to the pinion crazy.

This process comprises:

a first step in which at least one predetermined minimum force is exerted on the player to translate the synchronizer and cause a synchronization coupling thereof to the idler gear which induces a noise lower than a first predefined threshold, and

5 - a second step in which is exerted on the player a force greater than a second predetermined threshold and adapted to constrain the dog to angularly shift the synchronizer, then translates the dog to a predetermined minimum speed so as to cause a coupling of this last to the crazy gear that induces a noise below the first threshold.

) By reducing the noise induced by the preselection of a ratio below a predefined threshold, they are rendered almost inaudible, even when the general noise induced by the vehicle is low, and therefore when the vehicle speed is low.

The method according to the invention may comprise other characteristics that can be taken separately or in combination, and in particular:

the first step may comprise a first substep in which a minimum predefined first force is exerted on the player in order to translate the synchronizer until it comes into contact with the idle gear by inducing a noise below the first threshold; predefined, and a second substep in which is exerted on the player a second minimum effort preset to translate the synchronizer and cause a synchronization coupling thereof to the idler gear which induces a noise below the first predefined threshold;

in the second sub-step synchronization coupling can be caused for a duration which is less than a third predefined threshold;

The third threshold may be equal to about one second;

- The first step can be triggered when it does not detect a willingness of the driver of the vehicle to substantially modify a dynamic vehicle while a report must be preselected.

The invention also proposes a device for controlling the preselection, in a vehicle, of a ratio of a double-clutch gearbox comprising at least one player, secured in rotation to a secondary shaft while being able to translate on the latter, and comprising at least one dog, adapted to be translated to be coupled to a idler gear mounted free rotation on the secondary shaft, and at least one synchronizer 5 adapted to be translated to be coupled to the idler.

This device is arranged to trigger the exercise on the player of at least a predetermined minimum effort to translate the synchronizer and cause a synchronization coupling of the latter to the idler gear that induces a noise below a first predefined threshold, then to trigger) the exercise on the player of a force greater than a second predetermined threshold and suitable to constrain the dog to angularly shift the synchronizer, then to trigger the translation of the clutch to a minimum speed predefined so as to cause a coupling of this last to the crazy gear that induces a noise below the first threshold.

The invention also proposes a calculator comprising a control device of the type of that presented above.

The invention also proposes a vehicle, possibly of automobile type, and comprising, on the one hand, a heat engine coupled to a double-clutch gearbox and comprising at least one sliding device, secured in rotation to a secondary shaft while can be translated on the latter, and having at least one dog, adapted to be translated to be coupled to a idler gear mounted free rotation on the secondary shaft, and at least a synchronizer adapted to be translated to be coupled to the pinion crazy, and, on the other hand, a calculator of the type of that presented above.

Other features and advantages of the invention will become apparent upon consideration of the following detailed description, and the accompanying drawing, in which the single figure schematically illustrates an example of an algorithm implementing a control method according to the invention.

The object of the invention is in particular to propose a method, and an associated device, for controlling the preselection, in a vehicle, of a ratio of a double-clutch gearbox.

In the following, by way of non-limiting example, the double clutch gearbox is considered to be part of an automobile-type vehicle, such as a car. But the invention is not limited to this type of vehicle. It concerns indeed any vehicle that can be driven by a driver and comprising a heat engine coupled to a double clutch gearbox. Consequently, the invention relates in particular to land vehicles (cars, motorcycles, commercial vehicles, coaches (or buses), trucks, road vehicles, construction machinery, handling equipment, and trains), and maritime vehicles (or river).

In a vehicle, the dual-clutch transmission is part of a transmission chain that also includes a heat engine, a drive shaft, two drive shafts, and a supervisor (or calculator) to supervise (or manage) its operation.

For example, the drive shafts are responsible for rotating the front wheels of the vehicle. But in a variant they could be charged to rotate the rear wheels of the vehicle.

The engine comprises a crankshaft defining the drive shaft.

The gearbox includes two concentric primary shafts and

5 two secondary trees.

The primary shafts are designed to receive the engine torque (thermal) via the two corresponding clutches. Moreover, these primary shafts comprise driving gears which are engaged simultaneously with idler gears corresponding secondary trees with

) which they form pairs.

The secondary shafts are coupled to the drive shaft, usually via a differential. Each secondary shaft comprises at least one player (and generally several) operated by a control fork. Each player is more specifically secured in rotation to a

5 secondary shaft due to the existence of longitudinal grooves on the latter, while being able to translate on the latter in the longitudinal direction. Furthermore, each player comprises at least one synchronizer and at least one clutch coupled to this synchronizer by a mechanism allowing decoupling.

) Each synchronizer is adapted to be translated in the longitudinal direction to be coupled to a idler gear mounted free rotation on its secondary shaft during a so-called synchronization phase. Each dog is adapted to be translated in the longitudinal direction, after angularly shifting the associated synchronizer during a phase generally called

5 "devirage", to be coupled to the idler gear that has been synchronized by the synchronizer associated with it during a phase generally called "interconnection". It will be understood that the coupling of a synchronizer to a idler gear is intended to synchronize the speed of rotation of the latter to that of the secondary shaft which carries it, and that the coupling of a clutch to this

) same idle gear is intended to temporarily temporarily rotate the latter to the secondary shaft that carries it.

For example, each player can comprise at least: a hub secured in rotation to its secondary shaft thanks to splines

a sleeve mounted in translation on the hub and defining the clutch,

a synchronizing ring (or synchronizer) comprising a female conical portion adapted to be coupled to a male conical portion of a

5 crazy gear, and

- An arming mechanism installed between an inner face of the sleeve and an outer face of the hub, and for translating the synchronizing ring (or synchronizer) to couple to the idle gear when the sleeve / claw is translated.

As indicated above, the object of the invention is in particular to propose a method for enabling the preselection of a gear ratio of the double-clutch transmission described above.

Such a control method comprises first and second steps that can be implemented by a control device. The latter can,

For example, be part of the supervisor or computer that controls the drive chain or only the gearbox. But in an alternative embodiment, it could be in the form of equipment possibly coupled to the aforementioned supervisor or computer. Therefore, this control device can be realized in the form of software modules

) (or computer or "software"), or a combination of electronic circuits (or "hardware") and software modules.

A first step, the method according to the invention, consists at least in exercising on the player (concerned by the preselection decided by the supervisor or calculator) at least a predetermined minimum effort to

5 translate the associated synchronizer and cause synchronization coupling thereof to the idler gear that induces a noise lower than a first predefined threshold.

The first threshold is chosen so that the noise induced by the synchronization operation is virtually inaudible in the passenger compartment of the vehicle, including

) when the general noise induced by the vehicle is low, and therefore when the speed of the vehicle is low. For example, this first threshold may be chosen so as to correspond to an acoustic power level equal to about 72 dBA. It will be understood that this exercise of minimal effort is triggered by the control device when the supervisor or calculator has decided on a pre-selection.

It will be appreciated that the first step can be optionally subdivided into two sub-steps. A first sub-step (so-called synchronization approach) intended to translate the synchronizer longitudinally until it comes into contact with the idle gear, and a second substep (called synchronization) intended to gradually synchronize the speed of rotation of the idler gear on the speed of rotation of the synchronizer.

In this case, one can exert on the player (concerned by the preselection decided by the supervisor or calculator) a first minimum effort predefined in the first substep, then a second minimum effort predefined in the second substep. Of course, these first and second minimum forces are both intended to induce noise that is lower than

5 at the first predefined threshold. Moreover, these first and second minimum forces may be different. For example, the second minimal effort may be slightly greater than the first minimal effort.

When the player is arranged as described above (by way of non-limiting example), the first minimal effort is intended to translate the

) sleeve / dog to translate the cocking mechanism so that it slightly translates the synchronizing ring on the idler gear (without coupling), and the second minimal effort is intended to translate the sleeve / clutch to that it translates the synchronizing ring on the idler gear to couple them closely to synchronize them. When the phase of

5 synchronization is complete, there is no more resisting torque between the synchronizing ring (or synchronizer) and the sleeve / clutch.

Each pre-defined minimum effort can be determined by tests (or tests) carried out in a test laboratory or in the factory for the gearbox considered.

) For example, the first minimum force corresponds to a force that is slightly greater than the resistant force that the sleeve must overcome to translate the cocking mechanism so that it slightly translates the synchronizing ring on the idler gear (without causing their coupling). The second minimum effort corresponds to a force that is slightly greater than the resistant force that the sleeve must overcome to translate the synchronizing ring on the idler gear to cause their coupling for synchronization.

It should be noted that each minimum effort can be converted into a speed of movement of the synchronizer which is used to define a control setpoint of the range which moves the player comprising this synchronizer.

Preferably, in the first step, and more precisely in the second substep when it is provided, coupling of the

) synchronization for a duration that is less than a third predefined threshold.

For example, this third threshold may be equal to about one second. But other third threshold values can be used according to the synchronizer technology.

Also preferably, the first step is carried out when a determination of the driver of the vehicle to substantially modify the dynamics of the vehicle while a report is to be preselected is detected. In other words, in the absence of a temporal constraint of passage of a new report, one (the control device) can decide to carry out the

) first step (then the second step). Note that the detection of the will of the driver can be done during the first step. In this case the first step is initiated as soon as the supervisor (or calculator) has decided to pre-select a report.

A second step, of the method according to the invention, consists at least in

5 exert on the player a force greater than a second predetermined threshold and suitable to constrain the dog to angularly shift the synchronizer (unwinding phase), then to translate the dog to a predetermined minimum speed so as to cause a coupling of the latter to crazy gear that induces a noise below the first threshold.

It will be understood that the exercise of a force greater than the second threshold and the translation of the clutch at the minimum speed are triggered by the control device when the synchronization phase is completed.

This effort above the second threshold can be determined by means of tests (or tests) carried out in a test laboratory or in the factory for the gearbox considered.

For example, the force greater than the second threshold corresponds to a force that is slightly greater than the resistant force that must be overcome to allow the unwinding. It will be noted that this effort can be converted into a speed of movement of the synchronizer which is used to define a control setpoint of the range which moves the player comprising this synchronizer.

The predefined minimum speed is preferably greater than one

) value below which there is a risk of causing a desynchronization.

But it must also be strictly below a maximum speed beyond which it is likely to induce a "grid bottom" noise that would be audible in the passenger compartment of the vehicle. If the speed is too high when the player arrives at the bottom of the grid, the player is stopped net, which

5 produces a shock sound. It is therefore preferable to have a sliding speed of the player to the zero value when the player arrives at the bottom of the grid (but this requires a very good knowledge of the position of the grid bottom for the gearbox considered, as well as control of dispersions of movement speed and positions of the player).

These minimum and maximum speeds can be determined by means of tests (or tests) carried out in a test laboratory or in the factory for the gearbox considered.

Note that this speed of movement of the synchronizer is used to define a control set of the range which moves the

5 player including this synchronizer.

When the player is arranged as described above (by way of non-limiting example), the force greater than the second threshold is intended to translate the sleeve / clutch to angularly shift (or rotate) the synchronizing ring (or synchronizer) in order to allow an alignment of the splines of the idler gear in the middle of the splines of the sleeve (unwinding phase), and the translation of the sleeve / clutch to the minimum speed is intended to mesh the splines of the sleeve / clutch with corresponding jaw set on the idle gear. FIG. 1 is a diagrammatic illustration of a nonlimiting example of an algorithm implementing a control method according to the invention.

In a step 10, one (the calculator or supervisor) determines a

5 report to preselect.

In a step 20, the (control device) performs a test to determine if there is a time constraint of passage of a new report. To do this, the control device can analyze the parameters that define the current dynamics of the vehicle, and therefore the

) driver behavior, such as depressing or releasing the brake pedal and depressing or releasing the accelerator pedal.

If the control device D does not detect a desire of the driver of the vehicle to substantially modify the dynamic of the vehicle then

5 that a report must be preselected (which corresponds to an absence of time constraint of passage of a new report), then it performs a step 30 corresponding to the first and second steps of the method according to the invention. The preselection is then performed in a so-called reduced noise mode.

On the other hand, if the control device D detects a will of the

) driver of the vehicle to substantially change the dynamics of the vehicle while a report must be preselected (which corresponds to a time constraint of passage of a new report, for example due to a sudden depression of the pedal of brake or accelerator), then it performs a step 40 in which it triggers the realization of a

5 classic preset. By "conventional preselection" is meant here a preselection in which the forces exerted on the synchronizer and on the dog and the speed of displacement of the clutch (once the unwinding has been performed) are all higher than those used in the reduced-noise mode, and so are predefined regardless of the noise they induce.

The invention offers several advantages, among which:

a decrease in the acoustic level during the preselection passages for which there is no time constraint for the passage of a new report, economic gain and weight gain because there is no need to add a layer of soundproofing material under the hood of the vehicle to reduce the noise induced by the preselection passages.

Claims

1. Method for controlling the preselection, in a vehicle, of a ratio of a double-clutch gearbox and comprising at least one shifter, secured in rotation to a secondary shaft while being able to translate on the latter, and comprising at at least one clutch, capable of being translated to be coupled to an idler gear mounted to rotate freely on said secondary shaft, and at least one synchronizer capable of being translated to be coupled to said idler gear, characterized in that it comprises a first step (30) in which at least a predefined minimum effort is exerted on said player in order to translate said synchronizer and cause a synchronization coupling of the latter to said idler gear which induces a noise lower than a first predefined threshold, and a second step (30) ) in which a force greater than a second predefined threshold is exerted on said clutch and capable of forcing said clutch to angularly offset said synchronizer, then said clutch is translated at a predefined minimum speed so as to cause coupling of the latter to said idler gear which induces noise lower than said first threshold.

2. Method according to claim 1, characterized in that said first step (30) comprises a first sub-step in which a first predefined minimum effort is exerted on said player in order to translate said synchronizer until it comes to the contact of said idler gear by inducing a noise lower than said first predefined threshold, and a second sub-step in which a second predefined minimum effort is exerted on said player in order to translate said synchronizer and cause a synchronization coupling of the latter to said idler gear which induces noise lower than said first predefined threshold.

3. Method according to claim 2, characterized in that in said first step (30) said synchronization coupling is caused for a duration less than a third predefined threshold.

4. Method according to claim 3, characterized in that said third threshold is equal to approximately one second.

5. Method according to one of claims 1 to 4, characterized in that said first step (30) is triggered when a desire of a driver of said vehicle to significantly modify a current dynamic of said vehicle is not detected when a gear must be preselected.

6. Device for controlling the preselection, in a vehicle (V), of a

5 gear of a double clutch gearbox (BV) comprising at least one shifter, secured in rotation to a secondary shaft while being able to translate on the latter, and comprising at least one clutch, capable of being translated to be coupled to an idler gear mounted to rotate freely on said secondary shaft, and at least one synchronizer capable of being translated for

) be coupled to said idler gear, characterized in that it is arranged to trigger the exercise on said sliding gear of at least a predefined minimal effort in order to translate said synchronizer and cause a synchronization coupling of the latter to said idler gear which induces a noise lower than a first predefined threshold, then to trigger the exercise on said player of a

5 effort greater than a second predefined threshold and capable of forcing said clutch to angularly shift said synchronizer, then to trigger the translation of said clutch at a predefined minimum speed so as to cause a coupling of the latter to said idler gear which induces a noise lower than said first threshold.

) 7. Computer, characterized in that it comprises a control device according to claim 6.

8. Vehicle comprising a thermal engine coupled to a double-clutch gearbox and comprising at least one slider, secured in rotation to a secondary shaft while being able to translate on the latter, 5 and comprising at least one clutch, capable of being translated to be coupled to an idler gear mounted to rotate freely on said secondary shaft, and at least one synchronizer capable of being translated to be coupled to said idler gear, characterized in that it further comprises a calculator according to claim 7.

) 9. Vehicle according to claim 8, characterized in that it is of the automobile type.