FR3140144A1 - CONTROL OF SILENT SHIFT OF A GEAR IN A CONTROLLED GEARBOX OF A VEHICLE - Google Patents

Abstract

A control method in a vehicle controls a gear change of a controlled gearbox and comprising a primary shaft and an actuator capable of operating a fork associated with a synchronizer. This method comprises a step (10-30) in which the actuator controls the force of the synchronizer in order to achieve synchronization with a first force setpoint until the speed of the primary shaft becomes comparable to a target speed , then controls the speed of the synchronizer in order to achieve interconnection using a first speed setpoint for a chosen duration, then a second speed setpoint strictly lower than this first speed setpoint. Figure 3

Description

CONTROL OF SILENT SHIFT OF A GEAR IN A CONTROLLED GEARBOX OF A VEHICLE Technical field of the invention

The invention concerns vehicles which include a controlled gearbox, and more specifically the control of gear changes in such gearboxes.

State of the art

It is important to note that the invention relates to any type of gear change in a controlled gearbox, and therefore not only a shift immediately resulting in a gear change, but also a gear preselection with a view to a possible gear change. ratio (in the case of a double clutch gearbox (or DCT)).

Remember that a double clutch gearbox (or DCT) includes two parts (sometimes called “half gearboxes”) dedicated respectively to odd gears and even gears. Each part of such a gearbox comprises a primary shaft coupled to its own clutch, at least one secondary shaft coupled to drive wheels, and at least one synchronizer responsible for coupling the associated secondary shaft and primary shaft via at least one gear. during a synchronization phase followed by a interconnection phase. This makes it possible to simultaneously engage the two primary shafts in different gears, in order to allow very rapid gear changes under torque, that is to say without interrupting the vehicle's acceleration.

When one of the two parts of the DCT gearbox is engaged with a gear engaged on its primary shaft, for example the first part, the current rotation speed of the drive wheels is then equal to the current engine speed multiplied by the reduction of this engaged gear. The secondary shaft of the other non-engaged part of the gearbox, for example the second part, being coupled to these same driving wheels, the associated primary shaft frequently has a current rotation speed different from that of the first engaged part.

Each gear change is carried out in two stages. In a first step, when an even or odd gear is engaged in the gearbox, the computer controlling the latter anticipates the engagement of the next gear by preselecting an odd or even gear. This is what we call “passing the pre-selection”. In a second step, when certain conditions are met, the computer controls the engagement of the next gear by causing the clutch which is associated with the preselected gear to close and by opening the other clutch associated with the gear being engaged.

In a controlled gearbox, a gear change (change or preselection) is carried out by associated actuators and synchronizers during synchronization and clutching phases of an idler gear. During each of these phases, this actuator moves into precise positions in which it acts via a fork on the associated synchronizer. More precisely, in the synchronization phase, the actuator concerned controls the speed of the synchronizer, and in the interconnection phase the actuator concerned controls the force of the synchronizer.

Changing a gear can be imposed by the vehicle's transmission chain supervision computer when the vehicle is traveling at low speed, and therefore with a low noise level attributable to its powertrain (or GMP) and its driving ( aerodynamic noise). Note that the part of this acoustic level attributable to the GMP is even lower when the GMP is hybrid (thermal and electric) and the vehicle is in an all-electric driving phase (in which only the electric motor provides engine torque ).

In the presence of a low acoustic level, noises attributable to shocks in the gearbox during a gear change become audible to vehicle users, and may seem suspicious and be considered as resulting from a malfunction or a design error which harms the quality image of the vehicle. These shocks result from the impact of the clutches of an idler gear by the sleeve of the synchronizer concerned. Indeed, during the synchronization phase, the actuator is controlled by force, and this force is transmitted to the synchronization cone(s) via the fork coupled to this actuator. From a certain level of effort, the fork will “flex” and therefore deform. However, at the end of the synchronization phase, the synchronizer suddenly unlocks and therefore the actuator loses control of the control of the associated fork, and consequently the latter relaxes by an elastic effect and causes rapid movement of the sleeve coupled to this fork while the actuator is still controlled in force. There is then a relatively high risk that the teeth of the sleeve impact the dogs of the idler gear and therefore generate noise.

The invention therefore aims in particular to improve the situation.

Presentation of the invention

It proposes in particular for this purpose a control method, on the one hand, intended to be implemented in a vehicle to control a gear change of a controlled gearbox and comprising a primary shaft and at least one actuator specific to actuate a fork associated with a synchronizer, and, on the other hand, comprising a step in which the actuator controls the force of the synchronizer in order to achieve synchronization with a first force setpoint, then controls the speed of the synchronizer in order to achieve a crabotage.

This control method is characterized by the fact that in its step the synchronization is stopped when a speed of the primary shaft becomes comparable to a target speed, and, after this stop, the interconnection is carried out by imposing on the actuator a first speed setpoint for a chosen duration, then a second speed setpoint strictly lower than the first speed setpoint.

Thanks to the invention, in the event of loss of contact between an actuator and the associated fork at the end of synchronization, we can now guarantee a resumption of this contact then the realization of the interconnection in good conditions, which makes it possible to limit noise potential shocks between the teeth of the sleeve and the inputs of the dogs of the idler gear concerned.

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

- in its stage, during interconnection, a second force setpoint can be imposed on the actuator which is strictly lower than the first force setpoint;

- in the presence of the first option, in its stage the second effort setpoint can be between 30% and 40% of the first effort setpoint;

- in its step, the first speed instruction is a maximum speed instruction;

- in the presence of the last option, in its stage the maximum speed setpoint can be between 270 millimeters/second and 330 millimeters/second;

- in its step the chosen duration can be between 15 ms and 25 ms;

- in its stage, the second speed setpoint can be between 60 millimeters/second and 90 millimeters/second.

The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a control method of the type of that presented above, in a vehicle comprising a controlled gearbox and comprising a primary shaft and at least one actuator capable of operating a fork associated with a synchronizer, to control the control of a gear change in this gearbox.

The invention also proposes a control device, on the one hand, intended to control in a vehicle a gear change of a controlled gearbox and comprising a primary shaft and at least one actuator capable of operating a fork associated with a synchronizer, and, on the other hand, comprising at least one processor and at least one memory arranged to carry out the operations consisting of controlling the actuator so that it controls the force of the synchronizer in order to achieve synchronization with a first setpoint d effort, then it controls this synchronizer at speed in order to achieve interconnection.

This control device is characterized by the fact that its processor and memory are also arranged to carry out the operations consisting of triggering a stop of synchronization when a speed of the primary shaft becomes comparable to a target speed, and, after this stop , to impose on the actuator a first speed setpoint for a chosen duration, then a second speed setpoint strictly lower than the first speed setpoint.

The invention also proposes a vehicle, possibly of automobile type, and comprising, on the one hand, a controlled gearbox and comprising a primary shaft and at least one actuator capable of operating a fork associated with a synchronizer, and, on the other hand, a control device of the type presented above.

Brief description of the figures

Other characteristics and advantages of the invention will appear on examination of the detailed description below, and the appended drawings, in which:

schematically and functionally illustrates an example of a DCT type gearbox, coupled to a thermal engine via a double clutch, and a gearbox computer equipped with a control device according to the invention,

schematically and functionally illustrates an exemplary embodiment of a gearbox computer comprising an exemplary embodiment of a control device according to the invention,

schematically illustrates an example of an algorithm implementing a control method according to the invention, and

schematically illustrates within a first diagram an example of temporal evolution of the force setpoint of a synchronization actuator during a gear preselection, in the presence of the invention, within a second diagram an example of temporal evolution of the speed setpoint of the synchronization actuator during the gear preselection, in the presence of the invention, and within a third diagram an example of temporal evolution of the speed of the primary shaft during the report preselection, in the presence of the invention and the first and second diagrams.

Detailed description of the invention

The invention aims in particular to propose a control method, and an associated DC control device, intended to allow control of the control of a silent change of gear in a DCT type BV gearbox intended to equip a vehicle.

We consider in what follows, by way of non-limiting example, that the vehicle is of the automobile type. This is for example a car. But the invention is not limited to this type of vehicle. It concerns any vehicle including a DCT type gearbox. Consequently, the invention relates in particular to land vehicles (cars, utility vehicles, campers, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), and tracked vehicles, for example), boats and aircraft.

Furthermore, we consider in what follows, by way of non-limiting example, that the vehicle V comprises a powertrain (or GMP) of hybrid type (thermal and electric), and therefore whose traction is ensured by at least one thermal motive machine MT and at least one electric motive machine (not shown)). But the GMP could be of a purely thermal type.

In addition, we consider in what follows, by way of non-limiting example, that the BV gearbox is a double clutch (or DCT). But the invention is not limited to this type of controlled gearbox. It concerns all types of controlled gearboxes.

We have schematically illustrated on the an example of a BV gearbox (here of the DCT type), coupled to a DC control device according to the invention and to a thermal motive machine MT of a GMP via a double clutch EM1, EM2, within a vehicle (not shown).

This MT thermal motive machine is responsible for providing a variable engine torque to move the vehicle.

The BV gearbox being, here, double clutch (or DCT), it is subdivided into two parts (or half-boxes) PBj (j = 1 or 2) each comprising a primary shaft APj coupled to its own clutch EMj and intended to be coupled to at least one secondary shaft ASk, and at least one actuator ACj capable of acting on an associated synchronizer Sj to synchronize the speed of an idler gear PF with that of its receiver shaft in a synchronization phase, and to couple this idler gear PF to its receiver shaft in a interconnection phase.

It will be noted that in the example illustrated non-limitingly on the , the gearbox BV comprises two secondary shafts ASk (k = 1 or 2) which are each part of the two parts PBj and therefore which each carry at least one synchronizer S1 of the first part PB1 and at least one synchronizer S2 of the second part PB2. Each synchronizer Sj is therefore associated here with a secondary shaft ASk to synchronize the speed of an idler gear PF of the latter (ASk), which constitutes its receiver shaft, with that of the primary shaft APj concerned in a synchronization phase , and to couple this idler gear PF to its secondary shaft (receiver) ASk in a interconnection phase. But other arrangements are possible, since each part (or half-gearbox) PBj comprises a primary shaft and one or more secondary shafts, with synchronizers placed either on the primary shaft or on a secondary shaft.

Each actuator ACj is arranged so as to act on a switching fork (not illustrated) which is itself adapted to act on a synchronizer Sj. Furthermore, each actuator ACj is associated with a displacement sensor and a force sensor (not illustrated). A force sensor is intended to measure the force that its actuator ACj exerts on the associated synchronizer Sj. A position sensor is responsible for determining at each instant the current position of its actuator ACj relative to a reference position. This makes it possible to control the different synchronizers Sj in position, effort, or speed, depending on the operating phase in which they are involved.

For example, each synchronizer Sj can include at least:

- a hub secured in rotation to a secondary shaft ASk thanks to internal splines cooperating with external splines of this secondary shaft ASk,

- a sleeve (or slider) mounted in translation on the hub, and suitable for being coupled to part of a ring gear of an idler gear PF,

- a synchronization ring comprising a female conical part capable of being coupled to a male conical part of an idler gear PF or of a coupling disk of the secondary shaft ASk, or to a crown with dogs integrating a cone of friction, and

- a cocking mechanism installed between an internal face of the sleeve and an external face of the hub, and intended to transmit, via the movement of the sleeve (or slider), a force on the synchronization ring to couple it to the idler pinion PF and thus carry out the indexing of the synchronization ring. This arming mechanism is also used to reset the synchronizer and mark neutral.

EM1 and EM2 clutches are controlled by AE1 and AE2 clutch actuators.

As mentioned above, the invention proposes in particular a control method intended to allow control of the control of a silent passage of a report in the BV gearbox of the vehicle.

This (control) method can be implemented at least partially by the DC control device (illustrated at least partially in Figures 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal (or DSP (“Digital Signal Processor”)), and at least one MD memory. This DC control device can therefore be produced in the form of a combination of electrical or electronic circuits or components (or “hardware”) and software modules (or “software”). For example, it can be a microcontroller.

The memory MD is live in order to store instructions for the implementation by the processor PR1 of at least part of the control process. The processor PR1 may include integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or non-wired connections. By integrated (or printed) circuit we mean any type of device capable of performing at least one electrical or electronic operation.

In the example illustrated without limitation in Figures 1 and 2, the DC control device is part of the CB gearbox computer. This is advantageous because it is the latter (CB) which controls the passage (here the preselection) of gear and the gear changes in the BV gearbox. But this is not obligatory. Indeed, the DC control device could include its own dedicated computer, which is then coupled to the CB gearbox computer, or could be part of another on-board computer than the latter (CB), such as for example the computer supervisor who is responsible for supervising the operation of the vehicle's transmission chain.

As illustrated without limitation on the , the (control) method, according to the invention, comprises a step 10-30 which is implemented when the GMP of vehicle V is operating and a gear must be passed (here preselected).

Step 10-30 of the method may include a possible sub-step 10 in which (the control device DC) controls the actuator ACj, involved in the passage (here the preselection) of the report, so that it controls in speed the synchronizer Sj associated with this actuator ACj. This is what those skilled in the art call the approach phase of the synchronizer Sj.

Step 10-30 of the method comprises a sub-step 20 in which (the control device DC) controls the actuator ACj so that it controls the synchronizer Sj in force, in order to achieve synchronization with a first setpoint d 'effort ce1. In this sub-step 20, we (the DC control device) decide to stop the synchronization when the rap speed of the primary shaft APj (concerned by the passage (here the preselection) of the report) becomes comparable to a target speed rc. The latter (rc) depends on the report currently in use and which is likely to be replaced by the report currently being preselected. The word “comparable” means equal to plus or minus 5%.

When it has been decided to stop the synchronization, step 10-30 of the method includes a sub-step 30 in which (the control device DC) controls the actuator ACj so that it controls the speed of the synchronizer Sj , in order to carry out a interconnection. In this sub-step 30, the (the DC control device controls the realization of) interconnection is carried out by imposing on the actuator ACj a first speed setpoint cv1 for a chosen duration dc, then a second speed setpoint cv2 strictly lower to this first speed instruction cv1.

In other words, as soon as we detect in sub-step 20 that the speed rap of the primary shaft APj (concerned by the passage (here the preselection) of the report) becomes comparable to the target speed rc, we stop sub-step 20 (synchronization completed) and we begin sub-step 30 of interconnection by imposing the first speed instruction cv1 for the chosen duration dc, then by imposing the second speed instruction cv2 until the interconnection is finished.

Thus, in the event of loss of contact between the actuator ACj and the associated fork at the end of synchronization, we can guarantee a resumption of this contact by using the first speed setpoint cv1 for a (very) short duration chosen dc , then carrying out a interconnection in good conditions using a second speed setpoint cv2 notably smaller than the first speed setpoint cv1. This limits potential impact noise between the teeth of the sleeve and the inputs of the dogs of the PF idler gear concerned.

It will be noted that it is also advantageous in sub-step 30 of step 10-30 to impose (which the control device DC imposes) on the actuator ACj concerned a second force setpoint ce2 which is strictly lower to the first force instruction ce1 used during synchronization. This makes it possible to further limit potential impact noise between the teeth of the sleeve and the inputs of the dogs of the PF idler gear concerned.

For example, in sub-step 30 of step 10-30, the second effort setpoint ce2 can be between 30% and 40% of the first effort setpoint ce1. As an illustrative example, this second effort instruction ce2 can be equal to approximately 33% of the first effort instruction ce1. But other values of second force setpoint ce2 can be used. For example, this second force instruction ce2 can be chosen during the development phase of a vehicle similar to vehicle V.

Also for example, in substep 30 of step 10-30, the first speed setpoint cv1 can be a maximum speed setpoint (that is to say the largest speed setpoint that can be used for the passage (here the preselection) of gear in the BV gearbox). But this is not obligatory. Thus, the first speed setpoint cv1 could be a setpoint slightly lower than the maximum speed setpoint.

Also for example, in substep 30 of step 10-30, when the first speed setpoint cv1 is the maximum speed setpoint, the latter can be between 270 millimeters/second and 330 millimeters/second. As an illustrative example, this maximum speed instruction cv1 can be equal to 300 millimeters/second. But other maximum speed setpoint values cv1 can be used. For example, this maximum speed reference cv1 can be chosen during the development phase of a vehicle similar to vehicle V.

Also for example, in substep 30 of step 10-30, the chosen duration dc can be between 15 ms and 25 ms. As an illustrative example, this chosen duration dc can be equal to 20 ms. But other values of chosen duration dc can be used. For example, this chosen duration dc can be chosen during the development phase of a vehicle similar to vehicle V.

Also for example, in substep 30 of step 10-30, the second speed setpoint cv2 can be between 60 millimeters/second and 90 millimeters/second. As an illustrative example, this second speed reference cv2 can be equal to 75 millimeters/second. But other values of second speed reference cv2 can be used. For example, this second speed reference cv2 can be chosen during the development phase of a vehicle similar to vehicle V.

Note that the control device DC is arranged so as to control each actuator ACj associated with a synchronizer Sj capable of carrying out a change (here a preselection) of report.

We have schematically illustrated on the three diagrams of temporal evolution of parameters involved in the invention.

The first diagram (the top) includes an example of the temporal evolution of the force setpoint which a synchronization actuator ACj is forced to use during a shift (here a preselection) of gear.

The second diagram (middle) includes an example of temporal evolution of the speed reference cv that the synchronization actuator ACj (mentioned in the previous paragraph) is forced to use during the gear change (here the preselection).

The third diagram (the lowest) includes an example of temporal evolution of the rap speed of the primary shaft APj during the passage (here the preselection) of gear, in the presence of the first and second diagrams.

Synchronization ps begins at a time t1, after a possible approach phase not shown (sub-step 10). Between times t1 and t2, the effort setpoint ce is rapidly increased up to the first effort setpoint ce1 (possibly maximum). Then, we maintain this first force instruction ce1 until we detect at a time t3 that the rap speed of the primary shaft APj concerned has become comparable to the target speed rc. Time t3 is the end time of ps synchronization and the start time of pc calibration.

Between times t3 and t4 (with t4 - t3 = dc), the first speed setpoint cv1 is imposed on the actuator ACj, so that in the event of loss of contact between this actuator ACj and the associated fork, we have a recovery guarantee of this contact. Then, between times t4 and t5, the second speed setpoint cv2 is imposed on the actuator ACj (with cv2 < cv1), in order to achieve the pc interconnection in the best conditions. Note that in order to minimize the acoustic level of a possible shock between the teeth of the sleeve and the inputs of the clutches of the idler gear PF concerned, during the entire pc interconnection (and therefore between times t3 and t5) a setpoint is imposed of effort ce equal to the second effort instruction ce2 (with ce2 < ce1).

Note also, as illustrated non-limitatively in the , that the CB gearbox computer (or the DC control device computer) can also include a mass memory MM1, in particular to store the current rpm of the primary shaft APj concerned, as well as any data intermediaries involved in all its calculations and processing. Furthermore, this CB gearbox computer (or the DC control device computer) can also include an IE input interface for receiving at least the current rpm, to use it in calculations or processing, possibly after having shaped it and/or demodulated and/or amplified, in a manner known per se, by means of a digital signal processor PR2. In addition, this CB gearbox computer (or the DC control device computer) can also include an IS output interface, in particular to deliver messages (or orders) imposing the first cv1 or second cv2 speed setpoint and/or or the first ce1 or second ce2 effort instruction.

It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1 is capable of implementing the control method described above to control the control of a gear change in the BV gearbox of the vehicle V.

Claims (10)

Control method for controlling a gear change in a vehicle (V) of a controlled gearbox (BV) and comprising a primary shaft (APj) and at least one actuator (ACj) capable of operating a fork associated with a synchronizer (Sj), said method comprising a step (10-30) in which said actuator (ACj) controls the force of said synchronizer (Sj) in order to achieve synchronization with a first force setpoint, then controls the speed of said synchronizer (Sj). ) in order to carry out a interconnection, characterized in that in said step (10-30) said synchronization is stopped when a speed of said primary shaft (APj) becomes comparable to a target speed, and, after this stop, said interconnection is carried out by imposing on said actuator (ACj) a first speed setpoint for a chosen duration, then a second speed setpoint strictly lower than said first speed setpoint. Method according to claim 1, characterized in that in said step (10-30) during said interconnection a second force setpoint is imposed on said actuator (ACj) strictly lower than said first force setpoint. Method according to claim 2, characterized in that in said step (10-30) said second effort setpoint is between 30% and 40% of said first effort setpoint. Method according to one of claims 1 to 3, characterized in that in said step (10-30) said first speed setpoint is a maximum speed setpoint. Method according to claim 4, characterized in that in said step (10-30) said maximum speed setpoint is between 270 millimeters/second and 330 millimeters/second. Method according to one of claims 1 to 5, characterized in that in said step (10-30) said chosen duration is between 15 ms and 25 ms. Method according to one of claims 1 to 6, characterized in that in said step (10-30) said second speed setpoint is between 60 millimeters/second and 90 millimeters/second. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the control method according to one of claims 1 to 7, in a vehicle (V) comprising a controlled gearbox (BV) and comprising a primary shaft (APj) and at least one actuator (ACj) capable of operating a fork associated with a synchronizer (Sj), to control the control of a gear change in said gearbox (BV). Control device (DC) for controlling a gear change in a vehicle (V) of a controlled gearbox (BV) and comprising a primary shaft (APj) and at least one actuator (ACj) capable of operating an associated fork to a synchronizer (Sj), said control device (DC) comprising at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting of controlling said actuator (ACj) so that it drives in effort said synchronizer (Sj) in order to achieve synchronization with a first effort setpoint, then it controls said synchronizer (Sj) in speed in order to achieve interconnection, characterized in that said processor (PR1) and memory (MD ) are further arranged to carry out the operations consisting of triggering a stop of said synchronization when a speed of said primary shaft (APj) becomes comparable to a target speed, and, after this stop, to impose a first instruction on said actuator (ACj). speed for a chosen duration, then a second speed setpoint strictly lower than said first speed setpoint. Vehicle (V) comprising a controlled gearbox (BV) and comprising a primary shaft (APj) and at least one actuator (ACj) capable of operating a fork associated with a synchronizer (Sj), characterized in that it comprises in in addition to a control device (DC) according to claim 9.