WO2015092177A1

WO2015092177A1 - Method and device for controlling the recharging of a hydraulic accumulator of a controlled gearbox, as a function of pressure

Info

Publication number: WO2015092177A1
Application number: PCT/FR2014/052861
Authority: WO
Inventors: Olivier BALENGHIEN; Christine HASCOET
Original assignee: Peugeot Citroen Automobiles Sa
Priority date: 2013-12-16
Filing date: 2014-11-07
Publication date: 2015-06-25
Also published as: FR3014990B1; EP3084274A1; FR3014990A1

Abstract

A method controls the operation of means for recharging a hydraulic accumulator of a hydraulic actuator of a controlled gearbox of a vehicle comprising a combustion engine and able to operate in first and second modes in which said combustion engine is respectively running and switched off. This method comprises a step (20-50) in which, in the presence of a need to recharge the hydraulic accumulator as a result of a pressure below a predefined first threshold being detected therein, the method waits until the pressure drops below a predefined second threshold, strictly lower than the first threshold, when the vehicle is in the second mode, then the recharging means are actuated so that the pressure of the hydraulic accumulator rises above a predefined third threshold strictly higher than the first threshold.

Description

METHOD AND DEVICE FOR CONTROLLING THE RECHARGE OF A HYDRAULIC ACCUMULATOR OF A PILOT BOX, BASED ON PRESSURE

The invention relates to vehicles comprising a heat engine coupled to a controlled gearbox, and more specifically the control of the operation of recharging means of a hydraulic accumulator of a hydraulic motor of such a controlled gearbox.

Here "controlled gearbox" means any gearbox whose operation is controlled by a computer or supervisor and whose gearshift (or ratio) is provided by an electrohydraulic actuator. Therefore, it may be, for example, an automatic transmission, a manual gearbox or a gearbox dual clutch (or DCT).

As known to those skilled in the art, the controlled gearboxes generally comprise a hydraulic actuator responsible for moving on demand their shift forks. In order for this electro-hydraulic actuator to operate, it must be powered by a hydraulic accumulator whose pressure is controlled by recharging means comprising a hydraulic pump actuated by an electric motor.

When the pressure in the hydraulic accumulator is below a predefined minimum pressure, the hydraulic pump is operated by means of an electric motor to raise it, and when the pressure in the hydraulic accumulator exceeds a predefined maximum pressure. the operation of the hydraulic pump is interrupted.

This procedure of recharging the hydraulic accumulator is always operational when the starting function of the vehicle (allowing the engine to operate) is activated, for example by means of a "start key (or contact)". As soon as this start function is deactivated, the charging procedure is stopped. This mode of This results from the fact that in a vehicle with a controlled gearbox, the latter is always active, because as soon as the driver wants it, the clutch and gearshift must be immediately operational.

This charging procedure can be troublesome in terms of hearing when the vehicle can operate in a first mode in which its thermal engine is respectively in operation or in a second mode in which its engine is stopped. This is particularly the case for vehicles with a stop and restart control system

) or "stop and start" (or alternatively STT), and vehicles comprising a hybrid-type powertrain (that is to say comprising at least one heat engine and an auxiliary engine (or machine) (optionally of electric or hydraulic type)). It will be understood that when a vehicle of the aforementioned type is in its second mode

5 (thermal engine off), it is (very) silent and therefore the noise that is induced by the recharging of the hydraulic accumulator of the hydraulic gearbox actuator becomes audible in the passenger compartment, while it is not is not when the vehicle is in its first mode (heat engine in operation) due to the presence of a masking noise generated by the

) thermal motor.

In the presence of such a charging noise, the driver may fear that there is a malfunction in his vehicle, particularly during the "inaction" phases in which it is substantially at a standstill with its engine stopped by the STT system (such as when stopping at a traffic light or in a traffic jam). This fear is all the more understandable as the noise of the recharge is quite acute, and similar to that of a siren, which is very far from a running engine noise, and apparently occurs. random (but in reality depending on the pressure in the hydraulic accumulator).

In this case, the driver may be tempted to return his vehicle to his dealer for examination, which causes him to waste time and possibly money.

To prevent such noises from disturbing the driver, it is possible to add a layer of soundproofing 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 for this purpose a method for enabling the control of the operation of recharging means of a hydraulic accumulator of a hydraulic actuator of a gearbox driven by a vehicle comprising a heat engine and adapted to operate in first and second modes in which the engine is

) respectively in operation and stopped.

This method comprises a step in which, in the presence of a need for recharging the hydraulic accumulator resulting from detection in the latter of a pressure lower than a first predefined threshold, it is expected that the pressure becomes less than a second predefined threshold,

5 strictly lower than the first threshold, when the vehicle is in the second mode, then the charging means is actuated so that the pressure of the hydraulic accumulator becomes greater than a third predefined threshold, strictly greater than the first threshold.

Thus, it increases the time that elapses between two refills and) thus decreases the probability that the recharging of the hydraulic accumulator is triggered when the vehicle is in its second mode (engine stopped).

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

5 - in the step, when the vehicle is in the first mode, it is possible to immediately actuate the recharging means so that the pressure of the hydraulic accumulator becomes greater than a fourth predefined threshold, strictly greater than the first threshold;

the third and fourth thresholds may be identical;

alternatively, the fourth threshold may be strictly less than the third threshold.

The invention also proposes a device for controlling the operation of recharging means of a hydraulic accumulator of a hydraulic actuator of a gearbox driven by a vehicle comprising a heat engine and adapted to operate in first and second modes in which the engine is respectively in

5 operation and stopped.

This device is arranged, in the presence of a need for recharging the hydraulic accumulator resulting from a detection in the latter of a pressure lower than a first predefined threshold, to wait for the pressure to become lower than a second predefined threshold, strictly lower than

) first threshold, when the vehicle is in the second mode, then to trigger an actuation of the recharging means so that the pressure of the hydraulic accumulator becomes greater than a third predefined threshold, strictly greater than the first threshold.

This device can also be arranged, in the presence of a need for

5 recharging the hydraulic accumulator resulting from a detection in the latter of a pressure lower than a first predetermined threshold, with the vehicle in the first mode, to trigger an immediate actuation of the recharging means so that the pressure of the hydraulic accumulator becomes greater than a fourth predefined threshold, strictly greater than 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, comprising a calculator of the type of that presented above, and

5 a heat engine coupled to a controlled gearbox and comprising a hydraulic motor coupled to a hydraulic accumulator, itself coupled to recharging means, and adapted to operate in first and second modes in which the engine is respectively in operation and stopped.

Other features and advantages of the invention will appear on examining the detailed description below and the attached 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 notably to propose a method, and an associated device, for controlling the operation of recharging means of a hydraulic accumulator of a hydraulic actuator of a controlled gearbox of a vehicle.

The following is considered as a non-limiting example, that the gearbox is part of a vehicle-type vehicle, such as a car. But the invention is not limited to this type of vehicle. It concerns any vehicle that can be driven by a driver, including a heat engine coupled to a gearbox.

) driven and clean to operate in first and second modes in which the engine is respectively in operation and stopped. Therefore, the invention particularly relates to land vehicles (cars, motorcycles, commercial vehicles, coaches (or buses), trucks, road vehicles, construction machinery, handling equipment, and trains), and vehicles

5 maritime (or fluvial).

Furthermore, it is considered in the following, by way of non-limiting example, that the vehicle comprises a conventional transmission chain (that is to say comprising a heat engine, a drive shaft, a clutch, a box of speeds (here piloted), a drive shaft, and a supervisor

) (or calculator) able to supervise (or manage) its operation, coupled with an automatic stop and start control system (or "stop and start" (or STT)). But the vehicle could comprise a hybrid type transmission chain (that is to say comprising at least one heat engine and a motor (or machine) auxiliary (possibly type

5 electric or hydraulic)).

Finally, it is considered in the following, by way of non-limiting example, that the gearbox is a manual gearbox driven. But the invention is not limited to this type of gearbox controlled. It concerns indeed any gearbox whose operation is controlled by a calculator

) or supervisor and whose passage of speed (or report) is provided by an electro-hydraulic actuator. Therefore, it may also be, for example, an automatic gearbox or a double clutch gearbox (or DCT). The transmission shaft is responsible for driving in rotation at least some wheels of the vehicle, for example those located at the front or rear. The engine comprises a crankshaft defining the drive shaft.

The gearbox comprises (here) at least one primary shaft and at least one secondary shaft. The primary shaft is intended to receive, via the clutch, the torque that is produced (here) by the heat engine and delivered to the motor shaft. The secondary shaft is coupled to each transmission shaft, generally via a differential.

) Furthermore, the gearbox (controlled) comprises an electro-hydraulic actuator responsible for moving on request its shift forks. This electro-hydraulic actuator is powered by a hydraulic accumulator whose pressure is controlled by recharging means comprising a hydraulic pump actuated by an engine

5 electric.

As indicated above, the object of the invention is notably to propose a method intended to allow the control of the operation of the aforementioned recharging means.

Such a control method comprises a step that can be implemented

) works by a control device. The latter may, for example, be part of the supervisor or computer that controls the transmission 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

5 can be realized in the form of software modules (or computer or "software"), or a combination of electronic circuits (or "hardware") and software modules.

The step of the method according to the invention is carried out each time that the computer (or supervisor), which controls the gearbox, decides that there is

) need to recharge the hydraulic accumulator because it has been detected in the latter a pressure Pac lower than a first threshold S1 predefined (ie Pac

<S1). The step of the process then consists, when this detection occurs (Pac

<S1) and that at the same time the vehicle is in its second mode (engine stopped - here at the request of the STT system), waiting for the pressure Pac to become lower than a second threshold S2 predefined, strictly lower than the first threshold (ie S2 <S1), then to activate the charging means so that this pressure Pac of the hydraulic accumulator 5 becomes greater than a third threshold S3 predefined, strictly greater than the first threshold S1 (ie S3> S1).

It will be understood that it is the control device which decides to wait for the pressure Pac to become just below the second threshold S2 (ie Pac <S2), then to trigger the actuation of the recharging means until the pressure Pac becomes just above the third threshold S3 (ie Pac> S3). Once the last condition (Pac> S3) is satisfied, the control device triggers the stopping of the recharging means.

The first threshold S1 is a minimum pressure that is usually used in a conventional operating mode (of the prior art) for

Determining when to operate the hydraulic pump with its electric motor (recharging means) to raise the pressure Pac in the hydraulic accumulator above a preset maximum pressure (hereinafter called the fourth threshold S4). The third threshold S3 is here at least equal to the fourth threshold S4 (case S3 = S4), and preferably

) slightly higher than the fourth threshold S4 (case S3> S4).

By using at least a second threshold S2 recharging trigger lower than the first threshold (conventional) S1 recharge trigger, it increases the duration between two refills of the hydraulic accumulator, and thus reduces the probability that the recharge is triggered

5 when the vehicle is in its second mode (engine stopped). If in addition is also used a third threshold S3 recharge interruption higher than the fourth threshold (conventional) S4 recharge interruption, it increases even more the duration between two refills of the hydraulic accumulator, and therefore decreases even more the probability that

) the charge is triggered when the vehicle is in its second mode (engine stopped). It is recalled that the recharge depends on the pressure Pac detected in the hydraulic accumulator, and therefore the need to recharge can occur at any time, including during a stop phase of the engine.

The second threshold S2 (recharge trigger) corresponds to the pressure which is just above the smallest pressure that the hydraulic accumulator can withstand to function properly and

5 normally. The value of this second threshold S2 can be determined by means of tests (or tests) carried out in a test laboratory or in the factory for the gearbox considered.

The third threshold S3 (recharge interruption) corresponds to the pressure which is just below the greatest pressure that can

) support the hydraulic accumulator to function properly and normally. The value of this third threshold S3 can also be determined by means of tests (or tests) carried out in a test laboratory or in the factory for the gearbox considered.

Preferably, in the process step, when the calculator (or

5 supervisor) decided that there was a need to recharge the hydraulic accumulator, but that the vehicle is in the first mode (thermal engine in operation), one (the control device) immediately actuates the recharging means so that the pressure of the hydraulic accumulator becomes greater than the fourth predefined (conventional) threshold S4, which is

) strictly greater than the first threshold S1 (ie S4> S1).

It will be understood that when the vehicle is in the first mode, the noise made by the engine can hide the noise that the hydraulic pump makes with its electric motor, and therefore we can go back to a smaller duration (conventional) between two refills, which is

5 then function of the first S1 and fourth S4 thresholds.

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, the calculator or supervisor determines a need to recharge the hydraulic accumulator because its pressure Pac is lower than the first threshold S1 (ie Pac <S1).

In a step 20, the (control device) determines whether the engine is stopped or not (or in other words if the vehicle is in his second mode or his first mode). To do this, the control device can analyze the value of a parameter that defines the operating state of the heat engine.

If the control device detects that the vehicle is in its second

In this mode, it performs a step 30 in which it waits for the second threshold S2 to be crossed by a slightly lower value. Then, when the pressure Pac of the hydraulic accumulator becomes lower than S2 (ie Pac <S2), the control device performs a step 40 in which it triggers the actuation of the recharging means. Once the pressure Pac has become just

) greater than the third threshold S3 (ie Pac> S3), the control device triggers the stopping of the recharging means.

On the other hand, if in step 20 the control device detects that the vehicle is in its first mode (heat engine in operation), then it performs a step 50 in which it immediately triggers a

5 conventional charging of the hydraulic accumulator. To do this, it triggers the immediate actuation of the recharging means to increase the pressure Pac of the hydraulic accumulator. Then, once the pressure Pac has become just above the fourth threshold S4 (ie S3> Pac> S4, for example), the control device triggers the stopping of the recharging means.

Steps 20 to 50 are part of the process step of the invention.

The invention offers several advantages, among which:

a decrease in the probability that the recharging of the hydraulic accumulator is triggered when the vehicle is in its second mode (engine stopped),

5 - the use of the engine noise to mask the noise induced by the operation of the hydraulic accumulator when the vehicle is in its first mode (thermal engine in operation),

- An economic gain and weight gain because we do not need to add a layer of soundproofing material under the hood of the vehicle

) to reduce the noise induced by recharging the hydraulic accumulator.

Claims

1. A method of controlling the operation of means for recharging a hydraulic accumulator of a hydraulic actuator of a controlled gearbox of a vehicle comprising a heat engine and adapted to operate in first and second modes in which said engine is respectively in operation and stopped, characterized in that it comprises a step (20-50) in which, in the presence of a need for recharging said hydraulic accumulator resulting from a detection in the latter of a pressure lower than a first predefined threshold, it is expected that said pressure becomes less than a second predefined threshold, strictly less than said first threshold, when said vehicle is in said second mode, then said recharging means is actuated so that said pressure of said hydraulic accumulator becomes greater than a third predefined threshold, strictly greater than said first threshold.

2. Method according to claim 1, characterized in that in said step (20-50), when said vehicle is in said first mode, said recharging means are immediately activated so that said pressure of said hydraulic accumulator becomes greater than a fourth threshold. predefined, strictly greater than said first threshold.

3. Method according to claim 2, characterized in that said third and fourth thresholds are identical.

4. Method according to claim 2, characterized in that said fourth threshold is strictly less than said third threshold.

5. Device for controlling the operation of means for recharging a hydraulic accumulator of a hydraulic motor of a gearbox controlled by a vehicle comprising a heat engine and adapted to operate in first and second modes in which said engine thermal device is respectively in operation and stopped, characterized in that it is arranged, in the presence of a need for recharging said hydraulic accumulator resulting from a detection in the latter of a pressure lower than a first predefined threshold, to wait until said pressure becomes less than a second predefined threshold, strictly less than said first threshold, when said vehicle is in said second mode, then to trigger an actuation of said recharging means so that said pressure of said hydraulic accumulator becomes greater than a third predefined threshold, strictly greater than said first threshold.

6. Device according to claim 5, characterized in that it is arranged, in the presence of a need for recharging said hydraulic accumulator resulting from a detection in the latter of a pressure lower than a first predetermined threshold, with said vehicle in said first mode, for triggering an immediate activation of said recharging means so that said pressure of said hydraulic accumulator becomes greater than a fourth predefined threshold, strictly greater than said first threshold.

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

8. Vehicle comprising a heat engine coupled to a controlled gearbox and comprising a hydraulic actuator coupled to a hydraulic accumulator, itself coupled to recharging means, said vehicle being adapted to operate in first and second modes in which said engine is respectively in operation and

Stopped, characterized in that it further comprises a computer according to claim 7.

9. Vehicle according to claim 8, characterized in that it is automotive type.