METHOD FOR CONTROLLING A BRAKE SYSTEM FOR A MOTOR VEHICLE

Abstract

The invention relates to a control method and a device (1) controlled by such a control method, wherein, when an internal combustion engine (12) of the motor vehicle is in its stop state during a temporary stop, and the wheels (132) of the motor vehicle are locked by a braking system or by a parking brake device (11), and a vacuum reservoir (14) used for brake assist is below a reference threshold, then, in the event of subsequent use of the brake pedal (16), the control unit ignores the braking request and inhibits the brake assist, so that the vacuum reservoir (14) is not activated and the internal combustion engine (12) is maintained in its stop state rather than being restarted. Figure 1

Description

Title of the invention: METHOD FOR CONTROLLING A BRAKE SYSTEM FOR A MOTOR VEHICLE

[0001] The technical context of the present invention is that of braking systems for motor vehicles. More particularly, the invention relates to a method for controlling a motor vehicle system.

[0002] In the prior art, motor vehicles equipped with an automatic start / stop system are known. Such systems allow the internal combustion engine to be automatically stopped when the vehicle is stationary and to be automatically restarted when the user wishes. Such a restart is generally controlled by pressing the accelerator pedal. Such systems are implemented, for example, during temporary stops of the motor vehicle, such as at a traffic light or intersection.

[0003] Such motor vehicles further comprise a braking system including a vacuum reservoir that can be recharged by a charging device coupled to the internal combustion engine. The braking system includes clamping elements associated with the wheels of the motor vehicle so that, when activated by a user via a brake pedal, a resistive torque can be exerted on the wheels of the motor vehicle. The vacuum reservoir thus forms a braking assistance device that multiplies the braking force from the application of the brake pedal.

[0004] To this end, a vacuum reserve control device measures the vacuum level and triggers a recharge of the vacuum reserve if the vacuum level is too low, i.e., below a reference threshold. The vacuum reserve control device thus ensures that the vacuum reserve is sufficient to provide the intended braking assistance, enabling the driver to stop the motor vehicle.

[0005] In particular, when the internal combustion engine is running, the control device checks that the vacuum reserve is sufficient to ensure that, following the next automatic shutdown of the internal combustion engine - during the next temporary shutdown for example - and in the event of a malfunction in restarting the internal combustion engine, the user of the motor vehicle will still benefit from the braking assistance in order to be able to immobilize or keep immobilized the motor vehicle.

[0006] Also, during a temporary stop of the motor vehicle, when the internal combustion engine has been automatically stopped by the automatic stop and start system, the vacuum reserve control device measures the amount of vacuum available in order to to verify that the latter does not reach the reference threshold below which the vacuum reserve would be insufficient for optimal operation of the braking assistance system. In such a case, the automatic start / stop system restarts the internal combustion engine to regenerate the vacuum reserve.

[0007] One drawback of these known arrangements stems from the behavior of the motor vehicle user. Indeed, during a temporary stop, when the internal combustion engine has been automatically shut down by the automatic stop / start system, the user may press the brake pedal one or more times, thereby activating the vacuum reserve, which consumes a portion of the stored vacuum with each press of the brake pedal. In the known arrangements, if the vacuum reserve falls below the aforementioned critical threshold, the automatic stop / start system triggers an automatic restart of the internal combustion engine.

[0008] This situation is not necessarily desirable since the motor vehicle is still immobilized and the user has not yet wanted to restart it.

[0009] The present invention aims to propose a new control method in order to address at least largely the previous problems and to lead to other advantages.

[0010] Another object of the invention is to avoid restarting the internal combustion engine in undesired usage situations.

[0011] Another objective of the invention is to reduce the consumption of the motor vehicle.

[0012] Another objective of the invention is to reduce the pollution generated by the vehicle to tomobile, particularly during periods of temporary stoppage.

[0013] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a method for controlling a vehicle fitting, the fitting comprising:

[0014] - an electric parking brake device for several wheels of the vehicle tomobile;

[0015] - a heat engine coupled to a drive chain of the motor vehicle;

[0016] - a braking system comprising a vacuum reservoir that can be recharged by a charging device coupled to the internal combustion engine, the braking system comprising clamping elements associated with the wheels of the motor vehicle, said braking elements being coupled to the vacuum reservoir;

[0017] - an electrical machine configured to allow the motor to restart thermal when said thermal engine is in a stop state;

[0018] - a control unit operating the electrical machine in order to restart the automatic twitching the internal combustion engine from its stop state;

[0019] the control method comprising the following steps when the heat engine is in its stop state: if the vacuum reserve is below a reference threshold, and if a vehicle immobilizer actuator is activated, then the control unit keeps the internal combustion engine in its stop state.

[0020] In the context of the present invention, the electric parking brake device is a parking brake activated by means of an electrical control, the parking brake allowing at least one of the wheels of the motor vehicle to be locked. When the parking brake device is activated, it is in its "brake engaged" state.

[0021] In the context of the present invention, the heat engine is a combustion engine that performs mechanical work using a pressurized gas obtained by burning a fuel. When the heat engine is running, it produces the aforementioned mechanical work and drives a primary output shaft. This mechanical work is then transmitted to the drive chain, which is mechanically coupled to the primary shaft. Conversely, when the heat engine is stopped, it is at rest, and the primary shaft is no longer rotating. In other words, the stop state of the heat engine corresponds to a situation in which the engine is activated but not running: the ignition key is in the "on" position, but the engine speed is zero, and the engine delivers no torque.

[0022] In the context of the present invention, the drivetrain is rotationally coupled to the internal combustion engine via the input shaft. The drivetrain of the motor vehicle is connected to the input shaft so that it can, in turn, be driven in rotation by the rotation of said input shaft. The rotational coupling of the drivetrain is achieved through a gearbox, preferably automated. The drivetrain comprises a drive shaft on which the wheels of the motor vehicle are mounted.

[0023] In the context of the present invention, the braking system is configured to generate a resisting frictional torque on the drivetrain and, more generally, on the wheels of the motor vehicle. The braking system is controlled by a pedal, referred to as the brake pedal, located in the passenger compartment of the motor vehicle. When the user activates the brake pedal, that is, when they depress it, they engage the braking system and apply pressure to the wheels of the motor vehicle in order to generate the resisting frictional torque and brake or bring the motor vehicle to a complete stop.

[0024] In the context of the present invention, the vacuum reservoir is a braking assistance device that amplifies the braking force applied by the brake pedal when it is pressed. The vacuum reservoir, using a pneumatic circuit, actuates the braking system by exploiting a vacuum. in the pneumatic circuit, authorized by the vacuum reserve. For this purpose, each application of the brake pedal consumes a portion of the vacuum stored in the vacuum reserve.

[0025] In the context of the present invention, the recharging device allows the vacuum reservoir to be recharged so that the braking assistance system can function. The recharging device compensates for all or part of the vacuum used during previous activations of the vacuum reservoir. The recharging device includes a component configured to generate a vacuum in the vacuum reservoir.

[0026] In the context of the present invention, the control unit comprises at least one microcontroller and / or at least one microprocessor and / or a specific integrated circuit.

[0027] Thus, the method according to the first aspect of the invention makes it possible to promote keeping the motor vehicle stationary and not restarting the internal combustion engine, unlike known arrangements, when the following two conditions are met:

[0028] - the vacuum reserve is at a particularly low level so that it would no longer It is possible to obtain brake assist at a later date, and

[0029] - if a motor vehicle immobilizer actuator is in the "brake engaged" state. In the context of the present invention, the vehicle immobilizer actuator can be of any type on the vehicle's assembly. The vehicle immobilizer actuator consists of any device—electrical or mechanical—available on the vehicle's assembly that generates the resisting frictional torque on the vehicle's wheels, as described above. In other words, the vehicle is immobilized and held stationary by activating the braking system.

[0030] If these two conditions are met, then the control unit does not control the electric machine to restart the internal combustion engine. Unlike previously known arrangements, the control unit maintains the internal combustion engine in its stopped state, despite any subsequent requests from the user who might again activate the braking system by pressing the brake pedal. In all cases, the internal combustion engine is not restarted and remains in its stopped state.

[0031] Thus, the control method prevents the internal combustion engine from restarting in undesired operating situations, thereby promoting its maintenance in the stopped state, i.e., when stopped. Consequently, the control method according to the invention makes it possible to reduce the fuel consumption of the motor vehicle and to reduce the pollution generated by the motor vehicle, particularly during periods of temporary shutdown.

[0032] The piloting method according to the first aspect of the invention includes, but is not limited to at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0033] - the arrangement includes an automated transmission comprising a selector of The automated transmission, and the vehicle's immobilizer actuator, is activated under one of the following conditions: (i) if the automated transmission selector is in the Park position, or (ii) if a Park finger on the automated transmission selector is engaged, or (iii) if the electric parking brake is activated. The automated transmission includes an automated gearbox coupled to an automatic clutch to allow shifting between gears. Additionally, the automated transmission selector allows the driver to select a gear ratio and / or configure the automated transmission in forward mode. Furthermore, the Park finger is a mechanical and / or electrical device that locks the torque transmission of the automated gearbox.

[0034] - the reference threshold is defined as a function of at least one state parameter of the A motor vehicle, such as, for example, its altitude and / or atmospheric pressure. In the context of the present invention, at least one state parameter of the motor vehicle is a parameter related to its location, or a parameter related to its operation. The ability to set the reference threshold based on such a state parameter allows for better adaptability of the motor vehicle according to its use.

[0035] According to a second aspect of the invention, a motor vehicle fitting is proposed, the fitting comprising:

[0036] - an electric parking brake device for several wheels of the vehicle tomobile;

[0037] - a heat engine coupled to a drive chain of the motor vehicle;

[0038] - a braking system comprising a vacuum reservoir that can be recharged by a charging device coupled to the internal combustion engine, the braking system comprising clamping elements associated with the wheels of the motor vehicle, said braking elements being coupled to the vacuum reservoir;

[0039] - an electrical machine configured to allow the motor to restart thermal when said thermal engine is in a stop state;

[0040] - a control unit operating the electrical machine in order to restart the automatic the internal combustion engine from its stop state, the control unit being configured to implement the control method according to the first aspect of the invention or according to any of its improvements.

[0041] In the context of the present invention, the electric parking brake device The arrangement conforming to the second aspect of the invention is a parking brake activated by means of an electrical control, the parking brake allowing at least one of the wheels of the motor vehicle to be blocked.

[0042] In the context of the present invention, the internal combustion engine of the device according to the second aspect of the invention is a combustion engine providing mechanical work from a pressurized gas obtained by burning a fuel. When the internal combustion engine is in its running state, it produces the aforementioned mechanical work and drives a primary output shaft in rotation. The mechanical work is then transmitted to the drive chain, which is mechanically coupled to the primary shaft. Conversely, when the internal combustion engine is in its stopped state, it is at rest and the primary shaft is no longer driven in rotation.

[0043] In the context of the present invention, the drivetrain of the assembly according to the second aspect of the invention is rotationally coupled to the internal combustion engine via the input shaft. The drivetrain of the motor vehicle is connected to the input shaft so that it can, in turn, be driven in rotation by the rotation of said input shaft. The rotational coupling of the drivetrain is achieved through a gearbox, preferably automated. The drivetrain comprises a drive shaft on which the wheels of the motor vehicle are mounted.

[0044] In the context of the present invention, the braking system of the device according to the second aspect of the invention is configured to generate a resisting frictional torque on the drivetrain and, more generally, on the wheels of the motor vehicle. The braking system is controlled by a pedal, referred to as the brake pedal, located in the passenger compartment of the motor vehicle. When the user activates the brake pedal, that is, when they depress it, they engage the braking system and apply pressure to the wheels of the motor vehicle in order to generate the resisting frictional torque and brake or bring the motor vehicle to a stop.

[0045] In the context of the present invention, the vacuum reservoir of the assembly according to the second aspect of the invention is a braking assistance device that amplifies the braking force applied by the brake pedal when it is pressed. The vacuum reservoir, using a pneumatic circuit, actuates the braking system by exploiting a vacuum in the pneumatic circuit, created by the vacuum reservoir. Each press of the brake pedal consumes a portion of the vacuum stored in the vacuum reservoir.

[0046] In the context of the present invention, the recharging device of the system according to the second aspect of the invention allows the vacuum reservoir to be recharged, so that the braking assistance can function. The recharging device This allows for the compensation of all or part of the vacuum used during previous uses of the vacuum reservoir. The recharge device includes a component configured to generate a vacuum during the vacuum recharge.

[0047] In the context of the present invention, the control unit of the layout according to the second aspect of the invention comprises at least one microcontroller and / or at least one microprocessor and / or a specific integrated circuit.

[0048] The arrangement according to the second aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0049] - according to a first embodiment, the recharging device comprises a pump a vacuum pump mechanically coupled to a primary shaft of the internal combustion engine. Thus, the vacuum pump operates when the primary shaft of the internal combustion engine is driven in rotation by the engine. In this case, the rotation of the internal combustion engine drives the vacuum pump, which generates a vacuum in the vacuum reservoir, thus recharging it with vacuum;

[0050] - Advantageously, the coupled vacuum pump is coupled and operated by a accessory belt for the internal combustion engine.

[0051] - according to a second embodiment, the charging device comprises a Fluid coupling between the vacuum reservoir and an intake of the internal combustion engine. In this embodiment, the intake is directly coupled to the vacuum reservoir, so that the direct operation of the intake causes a vacuum at the level of the vacuum reservoir, and therefore the recharge;

[0052] - advantageously, the fluidic coupling comprises at least one hose fluidly coupled to an intake valve of the internal combustion engine and to the vacuum reservoir.

[0053] According to a third aspect of the invention, a motor vehicle is proposed comprising an arrangement conforming to the second aspect of the invention or to any one of its improvements.

[0054] The motor vehicle is of the type of a thermal or hybrid vehicle.

[0055] Various embodiments of the invention are provided, incorporating, according to all their possible combinations, the different optional features set out here.

[0056] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given by reference to the accompanying schematic drawings on the other hand, in which:

[0057] [Fig-1] illustrates a schematic view of a first example of conforming arrangement to the second aspect of the invention;

[0058] [Fig.2] illustrates a schematic view of a second example of an arrangement conforming to the second aspect of the invention.

[0059] Of course, the features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0060] In particular, all the variants and all the embodiments described are combinable with each other if nothing prevents this combination from a technical point of view.

[0061] In the figures, the elements common to several figures retain the same reference.

[0062] With reference to FIGURES 1 and 2, the invention relates to a fitting 1 for a motor vehicle, fitting 1 comprising:

[0063] - an electric parking brake 11 for several wheels 132 of the vehicle automobile;

[0064] - a thermal engine 12 coupled to a traction chain of the motor vehicle;

[0065] - a braking system comprising a vacuum reservoir 14 that can be recharged by a charging device coupled to the internal combustion engine 12, the braking system comprising clamping elements associated with the wheels 132 of the motor vehicle, said braking elements being coupled to the vacuum reservoir 14;

[0066] - an electrical machine configured to allow the motor to restart thermal 12 when said thermal engine 12 is in a stop state;

[0067] - a control unit operating the electrical machine in order to restart the automatic tickly the internal combustion engine 12 from its stop state.

[0068] In accordance with the invention, the control unit is also configured to implement a method for controlling the arrangement 1, such that, when the internal combustion engine 12 is in its stopped state, if the following conditions are cumulatively met, namely:

[0069] - the vacuum reserve 14 is below a reference threshold, that is to say that it is at a particularly low level such that it would no longer be possible to obtain braking assistance subsequently; and

[0070] - if a motor vehicle immobilizer actuator is activated, i.e. that the wheels 132 of the motor vehicle are blocked by the braking system or by the electric parking brake device 11;

[0071] Thus, the control unit maintains the internal combustion engine 12 in its stop state. In other words, ii the conditions previously mentioned are met, and even if, possibly, the braking system were to be activated again by the user pressing a brake pedal 16, then the control unit does not control the electric machine in order to restart the internal combustion engine 12. On the contrary, the control unit ignores the braking request which would consume once again - one time too many - the already low vacuum reserve 14 - since it is below the reference threshold - and maintains the internal combustion engine 12 in its stop state.

[0072] According to a first embodiment illustrated in [Fig. 1], the recharging device comprises a vacuum pump mechanically coupled to a primary shaft 122 of the internal combustion engine 12. Thus, the vacuum pump operates when the primary shaft 122 of the internal combustion engine 12 is driven in rotation by the internal combustion engine 12. In this case, the rotation of the internal combustion engine 12 drives the vacuum pump, which generates a vacuum in the vacuum reservoir 14, thereby recharging it with a vacuum. By way of non-limiting example, the vacuum pump is coupled to and driven by an accessory belt 141 of the internal combustion engine 12.

[0073] According to a second embodiment illustrated in [Fig. 2], the recharging device comprises a fluid coupling between the vacuum reservoir 14 and an inlet of the internal combustion engine 12. In this embodiment, the inlet is directly coupled to the vacuum reservoir 14, such that the direct operation of the inlet causes a vacuum in the vacuum reservoir, and consequently, its recharging. By way of non-limiting example, the coupling between the inlet of the internal combustion engine 12 and the vacuum reservoir 14 comprises at least one hose 142 fluidically coupled to an inlet valve 121 of the internal combustion engine 12 and to the vacuum reservoir 14.

[0074] In summary, the invention relates to a control method and an arrangement 1 controlled by such a control method, in which, when a thermal engine 12 of the motor vehicle is in its stop state, during a temporary stop, when the wheels 132 of the motor vehicle are blocked by a brake system or by a parking brake device 11, and when a vacuum reserve 14 used for brake assistance is below a reference threshold, then in the event of subsequent use of the brake pedal 16, the control unit ignores the braking request and inhibits the brake assistance, so that the vacuum reserve 14 is not activated and the thermal engine 12 is maintained in its stop state rather than being woken up.

[0075] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the various features, forms, variants, and embodiments of the invention can be combined with one another in various ways, provided that they are not incompatible or mutually exclusive. of others. In particular, all the variants and embodiments described above can be combined with each other.

Claims

Claims

1. Method for controlling an arrangement (1) for an equipped motor vehicle, the arrangement (1) comprising: - an electric parking brake device (11) for several wheels (132) of the motor vehicle; - a heat engine (12) coupled to a traction train (13) of the motor vehicle; - a braking system comprising a vacuum reserve (14) which can be recharged by a recharging device coupled to the heat engine (12), the braking system comprising clamping members associated with the wheels (132) of the motor vehicle, said braking members being coupled to the vacuum reserve (14); - an electric machine configured to allow the restarting of the heat engine (12) when said heat engine (12) is in a stop state; - a control unit controlling the electric machine in order to automatically restart the heat engine (12) from its stop state;the control method comprising the following steps when the thermal engine (12) is in its stop state: - if the vacuum reserve (14) is lower than a reference threshold; and - if an actuator for immobilizing the motor vehicle is activated; - then the control unit maintains the thermal engine (12) in its stop state.;

2. A driving method according to the preceding claim, wherein the arrangement (1) comprises an automated transmission (15) comprising an automated transmission selector (15), and the vehicle immobilization actuator is activated for one or other of the following conditions: - if the selector of the automated transmission (15) is commanded to the Parking position; or - if a Parking finger of the selector of the automated transmission (15) is engaged; or - if the electric parking brake device (11) is in the “brake applied” state.

3. A control method according to any one of the preceding claims, wherein the reference threshold is defined as a function of the less than one motor vehicle status parameter, such as for example motor vehicle altitude and / or atmospheric pressure.

4. Arrangement (1) for a motor vehicle, the arrangement (1) comprising: - an electric parking brake device (11) for several wheels (132) of the motor vehicle; - a heat engine (12) coupled to a powertrain of the motor vehicle; - a braking system comprising a vacuum reserve (14) which can be recharged by a recharging device coupled to the heat engine (12), the braking system comprising clamping members associated with the wheels (132) of the motor vehicle, said braking members being coupled to the vacuum reserve (14); - an electric machine configured to allow the heat engine (12) to be restarted when said heat engine (12) is in a stop state;- a control unit controlling the electric machine in order to automatically restart the thermal engine (12) from its stop state, the control unit being configured to implement the control method according to any one of the preceding claims.;

5. Arrangement (1) according to claim 4, in which the recharging device comprises a vacuum pump mechanically coupled to a primary shaft (122) of the heat engine (12).

6. Arrangement (1) according to the preceding claim, in which the coupled vacuum pump is coupled and actuated by an accessory belt (141) of the thermal engine (12).

7. Arrangement (1) according to claim 4, in which the recharging device comprises a fluid coupling between the vacuum reserve (14) and an inlet of the heat engine (12).

8. Arrangement (1) according to the preceding claim, in which the fluid coupling comprises at least one hose (142) fluidly coupled to an intake valve (121) of the heat engine (12) and to the vacuum reserve (14).

9. Motor vehicle comprising an arrangement (1) according to any one of claims 4 to 8.

Images