FR3127029A1 - METHOD FOR AUTOMATIC STARTING CONTROL OF A THERMAL ENGINE COMPRISING PRIORITIZATION OF THE ELECTRICAL SUPPLY OF THE SYSTEMS - Google Patents

Abstract

The subject of the present invention is a method for controlling the automatic start of a heat engine of a motor vehicle, the method comprising a power supply prioritization arbitration inhibiting the start of the heat engine according to an inhibition request generated during the control of a robotic system, the method comprising the detection of a first request for inhibition (RQ1) of starting emitted by the robotic system and a second request for inhibition (Tin) of starting of the heat engine triggered from the instant of detection (t0). The invention relates to motor vehicle automatic stop and restart systems and prioritization management for the electrical power supply, in particular the 12V on-board network. Figure 3

Description

METHOD FOR AUTOMATIC STARTING CONTROL OF A THERMAL ENGINE COMPRISING PRIORITIZATION OF THE ELECTRICAL SUPPLY OF THE SYSTEMS

The field of the invention relates to a method for controlling the automatic start of a heat engine of a motor vehicle. The process relates more specifically to the phases of automatic stopping and restarting of the heat engine.

Most motor vehicles today are equipped with an automatic stop and restart system for the internal combustion engine. Conventionally, such a system comprises a direct current electric motor starter powered by the vehicle's on-board network, at 12V voltage. When starting, the electric current drawn by the starter is likely to cause a drop in voltage which can affect the electronic systems of the vehicle also supplied with 12V.

The reliability of the on-board network power system is vital for the vehicle and increasingly critical due to the increasing number of robotic systems on board vehicles. In addition to the numerous engine sensors, there are trajectory control systems, robotic braking systems, or even driving assistance functions which also require sensors and computers to perform the automated functions.

It is common practice to implement electrical system load shedding functions to ensure the supply of energy to the other systems considered to have priority depending on the driving situation. In the past, the applicant filed the patent document FR3059966A1 which describes a process for controlling the heat engine during an automatic maneuver aimed at guaranteeing the power supply to the systems. It describes in particular a solution for evaluating the energy needs for carrying out the maneuver, it determines the need to start up, or not, the heat engine before the maneuver and finally the control of the freezing of the operating state of the internal combustion engine throughout the manoeuvre. Freezing prevents it from being stopped and restarted during the maneuver to avoid a current draw affecting the power supply of the 12V systems which could disturb or interrupt the automatic maneuver.

Furthermore, to avoid voltage drops, use is generally made of a voltage maintenance device, known as DMT, associated with the starter. To make economies of scale, some manufacturers do not integrate this device into the power supply architecture and replace it with an intelligent system power supply prioritization function. For example, automatic stop and restart strategies provide that when stopping, certain robotic systems are ordered to be relieved, for example the air conditioning or the power steering, to then ensure the smooth running of the start and also limit consumption. electric.

Conversely, the prioritization function assigns other robotic systems a higher priority level than the starter. This is the case, for example, of the robotic parking brake system, the action of which takes priority in a restart sequence. The implementation of the protocol foresees that the brake system generates the inhibition request and transmits it to the heat engine control unit which consequently controls the starting prohibition. The generation of the inhibition request is dependent on the internal strategy of the brake system.

Some brake system OEMs configure a start inhibition to be issued only when an actuator draws a large electrical current. This is the case for a brake calliper tightening/loosening operation involving hydraulic pressure regulation by a solenoid valve. On the other hand, other equipment manufacturers generate an inhibition for all the pressure regulations of the hydraulic circuit of the actuators, including the fine regulations lasting a few milliseconds. These fine regulations are likely to cause several consecutive interruptions of the restart and ultimately a motor shutdown for safety purposes and to count consecutive restart failures.

To illustrate this situation, we have represented a situation of automatic stopping and restarting of the engine during which an inhibition request is generated twice successively at a time t0 and a time t3. The RG signal represents the engine speed. The lifting of the inhibition at time t0 corresponds to an operation of applying the parking brakes. Inhibition is lifted for about 300ms and ends at time t1. During this inhibition, a first rise in speed is observed, which is stopped. Then, at time t2, the engine speed is zero. At time t3, the motor initiates a restart and at the same time a second inhibition request is lifted by the parking brake system, due to fine regulation lasting a few milliseconds. This second inhibition causes the engine to stall at time t4 and finally an engine shutdown.

There is therefore a need to overcome the aforementioned problems. One objective of the invention is to avoid motor cutouts resulting from untimely inhibition generated by a robotic system. Another objective of the invention is to propose improved motor control prioritization management capable of supervising different strategies for generating restart inhibition requests.

More specifically, the invention relates to a method for controlling the automatic start of a heat engine of a motor vehicle, the method comprising a power supply prioritization arbitration inhibiting the start of the heat engine according to an inhibition request generated during the piloting of a robotic system, the method comprising the detection of a first start-up inhibition request emitted by the robotic system. According to the invention, the method further comprises a second request to inhibit the starting of the heat engine triggered from the moment of detection.

According to a variant, the second inhibition request is a delay of a predetermined duration.

According to a variant, the predetermined duration is between 500 ms and 1500 ms.

According to a variant, the first inhibition request is generated at the instant of triggering of a command to apply/release the robotic parking brake.

According to a variant, the first inhibition request is generated at the instant of triggering of an opening/closing command of a motorized element of a door of the vehicle.

There is also provided a motor vehicle comprising a heat engine, a means of starting the heat engine, at least one robotized system, an electric power supply means and an arbitration means capable of inhibiting the starting of the heat engine according to an inhibition request generated during the piloting of the robotized system, in which the arbitration means is configured to implement the start control method according to any one of the preceding embodiments.

According to a variant, the electrical supply means comprises a battery and the starting means and the robotic system are powered solely by the voltage delivered by the battery.

According to a variant, a first robotized system is a parking brake system with motorized callipers.

According to a variant, a second robotic system is a door system comprising a motorized element.

Alternatively, the starting means is an automatic stop and restart system starter.

The management method is advantageous in that it is compatible with the various managements of starting inhibition requests generated by the robotic systems. Thanks to the invention and the generation of the inhibition signal by the engine control unit, it ignores untimely changes in an inhibition signal generated by a robotic parking brake system. Successive start failures causing engine stalling are thus avoided.

Other characteristics and advantages of the present invention will appear more clearly on reading the following detailed description comprising embodiments of the invention given by way of non-limiting examples and illustrated by the appended drawings, in which:

is a graph representing an automatic start control method of a heat engine according to a solution of the state of the art.

is a simplified diagram of a motor vehicle powertrain designed to implement the control method according to the invention.

is a graph showing the automatic start control method performing the improved power supply prioritization management according to the invention.

In , a preferred embodiment of the invention is presented in which the powertrain comprises a traction chain comprising a thermal internal combustion engine 10, an automated transmission 11 of an engine torque to the wheels of the vehicle, a brake system robotic 12, an automatic stopping and restarting system 13 of the thermal engine 10, and an electric power supply system 17.

The heat engine 10 is controlled by a computer control unit 19, called the ECU (“Electronic Control Unit”). The stopped state and the running engine state are controlled according to control signals, for example according to the detection of a torque demand at the wheels resulting from the will of the driver, from a need for air conditioning passenger compartment, or even a need to recharge a battery electrically. The control unit constantly communicates to the other systems status information making it possible to coordinate all the systems of the powertrain, such as information indicating whether the engine is running, stopped or in the process of stopping, if a start is carried out by means of the starter or in autonomous mode, for example. The control unit 19 also supervises other systems of the powertrain, such as the electrical power supply system 17. For this purpose, the powertrain comprises means of communication, for example a communication bus 20 of the CAN type. (“Controller Area Network”), or a LIN (“Local Interconnect Network”) communication bus.

The automated transmission 11 is an automatic or semi-automatic gearbox transmission. It includes a clutch device associated with the gearbox, which are automatically controlled by a control unit for torque transmission and gear changes.

The automatic stop and restart system 13 of the heat engine 10, a system called "STT" for "Stop And Start" in English, comprises a means for starting the heat engine 10. The starting means may comprise a starter, or a alternator-starter. The purpose of the starting means is to operate and rotate the shaft of the thermal engine 10. In this preferred embodiment, the starter comprises a solenoid which makes it possible to engage the pinion of the starter on the flywheel and a direct current electric motor which makes it possible to drive the shaft of the heat engine 10 in rotation. control 19. The starter control circuit comprises for example one or more switching relays. The starter is said to be "reinforced" because it is sized to withstand several hundred thousand restarts.

A starting sequence comprises, in the event of detection of a need for a running engine, the control of a switching relay of the power supply system 17 to electrically supply the starter 13 so that it drives the shaft of the motor in rotation. 10. When the motor shaft is shutting down (life phase where the engine is rotating without injecting), in a range of speeds compatible with an autonomous restart, the thermal engine control unit controls the fuel injection without using the starter.

The electrical power supply system 17 comprises an on-board electrical network 15 of very low voltage, in operating voltage ranges of approximately 12V to 14V. The on-board electrical network 15 electrically supplies the powertrain systems and the control unit computers, such as the automatic stop and restart system 13 and the parking brake system 12, in particular. A low voltage battery system 14, having a voltage of 12V at its terminals, supplies the on-board network 15. The on-board electrical network 15 also comprises an Engine Relay Fuse Box 151, called BFRM, comprising the controlled switching relays in order to to selectively supply each of the vehicle systems, in particular the starter 13. The electrical supply system 17 further comprises an alternator 16 driven mechanically in rotation by the heat engine 10 whose function is to supply a supply voltage to the system power supply 17. In an alternative embodiment, the starter 13 and the alternator 16 can be replaced by an alternator-starter.

It will be noted that in this embodiment, the power supply system 17 does not include a DMT usually associated with the battery 14 and the starter 13, or a voltage converter. The starter 13 is therefore powered solely by the voltage delivered by battery 14. The positive terminal of the battery is electrically connected to the positive terminal of the electric motor of the starter. The absence of the DMT and the voltage converter makes it possible to reduce the cost of the power supply system 17.

To compensate for this absence, provision is therefore made for the control unit 19 of the heat engine to implement a module 21 for prioritizing the electrical power supply during automatic stop and restart sequences. It is nevertheless envisaged that the invention can be implemented even when the power supply system 17 includes a DMT or a voltage converter, without departing from the scope of the invention.

The purpose of the power supply prioritization function implemented by module 21 is to guarantee compliance with the voltage constraints of the 12V on-board network, in order to avoid voltage drops and malfunctions that could disturb the electrical behavior of robotic systems. and microprocessor computers. The invention proposes a method for managing the automatic start of the heat engine based on restart inhibition requests. These requests are generated by robotic powertrain systems to prioritize power management. In addition, the prioritization module 21 comprises a means for developing another inhibition request. This request is intended to cover untimely inhibitions of short duration, resulting for example from fine adjustments of the actuators of robotic systems. This request is made in the form of a timer or a counter that is triggered when an inhibition requested by a robotic system is detected. The timer is configured to reset once it has elapsed.

In this embodiment, the parking brake is placed at a higher priority level with respect to a request to restart the heat engine. It is also envisaged that other robotic systems may take priority over the starter, for example the robotic system of the vehicle doors.

The robotic system 12 is a brake system comprising means with controlled actuators for clamping and releasing the wheels when the vehicle is parked and stationary. The actuator means are motorized brake calipers. The brake system further comprises a computer control unit 18 for automatically supervising the actuator means of the system 12 according to the instructions of the driver or of a driving assistance system, for example the so-called ADAS system, to “Advanced Driver Assistance Systems” in English. An automatic parking maneuver function is capable of controlling the brake system 12. More specifically, the actuator means comprise a hydraulic circuit with a solenoid valve and/or an electric motor.

More specifically, the control unit 18 comprises a module 22 capable of generating status and control signals, designated by the term status flow or requests, which may include requests for inhibition RQ1 of the starting of the heat engine 10 These inhibition requests RQ1 are generated during the control of the brake system 12 during an application/release operation of the parking brakes. These requests are used in particular to respect the supply constraints of the 12V on-board network.

More precisely, a request signals a first state “No inhibition request”. There is therefore little or no electrical consumption by the actuators. We are in a situation of stable state of the actuators. An inhibition request RQ1 signals a second status "Restart inhibition request for application of the parking brake". An inhibition request RQ1 signals a third state "Starting inhibition request to release the parking brake". These last two states cause current to be drawn from the 12V on-board electrical network and require prioritization of the electrical supply. These requests generated by the module 22 are transmitted via the communication bus 20 to the prioritization module 21 of the control unit 19.

The prioritization module 21 of the control unit 19 is able to receive inhibition requests generated by other robotic systems, supplied by the supply system 17, and for which a priority level higher than the starter 13. Another robotic system 24 comprising a control unit 25 can be a vehicle door system comprising motorized elements. A prioritization strategy may also consist of first finalizing the closing of a door or window with a motorized actuator before starting the heat engine 10. The control unit 25 is in this case configured to generate requests for inhibition RQ2 of the starting of the heat engine 10 for the purposes of prioritizing the electrical power supply in accordance with the invention.

A BSI module 23 is arranged to centralize the information from the systems and sensors of the powertrain, in particular the data on the state of charge of the battery 14. It centralizes the data collected and transmits the information via the communication bus 20 to the other systems. A low state of charge of the battery 14 or an air conditioning request triggers an engine start to recharge the battery by means of the alternator 16 or drive the air conditioning compressor.

In , there is shown a graph of a sequence of automatic stopping and restarting of the vehicle comprising an operation of applying the parking brake. For safety criteria, the application of the parking brake is positioned at a priority level in relation to starting. During this sequence, the heat engine control unit 19 implements the automatic start control method according to the invention. The control unit 19 is provided with an integrated circuit computer and electronic memories, the computer and the memories being configured to execute the automatic start control method according to the invention. But this is not compulsory. Indeed, the computer could be external to the control unit 19, while being coupled to the latter 19. In the latter case, it can itself be arranged in the form of a dedicated computer comprising a possible dedicated program , For example. Consequently, the control unit, according to the invention, can be produced in the form of software (or computer (or even “software”)) modules, or else of electronic circuits (or “hardware”), or even of a combination of electronic circuits and software modules.

The graph includes an RG signal of the engine speed, expressed in rpm. On the abscissa, the time axis is represented in seconds. The dotted line status signal represents a first inhibition request signal RQ1, generated in this example by the parking brake system. As a variant, the signal RQ1 can be a signal generated by a motorized door system or any other robotic system whose electrical supply takes priority over the starter. The solid line status signal Tin represents a second inhibition request signal generated by the heat engine control unit.

According to this sequence, we observe, before time t0, that the thermal engine is stopped. The RG engine speed gradually decreases. This is, for example, a situation where the vehicle is stationary and the parking brake system is released. The vehicle's energy strategy controls the stopping of the engine automatically. At time t0, the parking brake system triggers a brake application operation. At the same time t0, a need for the engine running is detected, which triggers the start-up procedure, for example to start the air conditioning system or recharge the battery (also called the system's "Change of Mind").

In accordance with the management of prioritization of the 12V power supply, the brake system requests the inhibition of starting of the heat engine during the tightening operation. The brake system generates the inhibition request RQ1 between time t0 and time t1. The signal is driven high, corresponding to "Starting inhibition request for application of the parking brake". The request RQ1 lasts for example approximately 300 ms.

Simultaneously, an increase in the engine speed RG is observed, the starter has initiated rotation of the motor shaft, but the inhibition request RQ1 causes it to be interrupted. The starter is electrically disconnected from the fuel system. At time t2, the engine speed drops to zero.

In accordance with the invention, at the same time t0, when the heat engine control unit detects the inhibition request RQ1, the prioritization module controls a second inhibition request Tin between time t0 and time t4 , full line. The second request Tin has the function of maintaining the inhibition for a predetermined period in order to avoid the detection of untimely inhibitions of short duration, such as those resulting from a fine regulation of the pressure of the brake system. The request Tin has a duration at least strictly greater than the duration between the first rise, at time t0, and the second rise of request RQ1, at time t3. Throughout the duration of the second inhibition request Tin, the prioritization arbitration suspends motor starting.

In this preferred embodiment, the second request Tin is a timer, or a counter, of a predetermined and configurable duration, in a value range of 500ms to 1500ms, for example 700ms. This duration is sufficient to cover the duration of the first rise until the appearance of a fine regulation of pressure, if necessary.

At time t4, after the timeout period has elapsed, the request Tin is deactivated. There are then no more active inhibition requests. Engine start is allowed. At time t5, we assume that a running engine requirement is still present. The motor start sequence is triggered. The starter is electrically powered and is placed in torque transmission with the heat engine shaft. The RG engine speed increases. Fuel injection is controlled, then the engine enters a running regime independently.

The sequence of the control method according to the invention applies identically for an automated release operation of the parking brake system, as well as for any other robotic system whose electrical power supply takes priority over starting the heat engine, such as for example a robotic door system. The invention finds an advantageous application for electrical supply systems of the on-board network without a DMT or voltage converter. The invention applies to powertrains comprising a heat engine equipped with an automatic stop and restart system, but also to hybrid vehicles whose traction chain is equipped with an electric traction machine.

Claims (10)

Method for controlling the automatic start of a thermal engine (10) of a motor vehicle, the method comprising an electrical power supply prioritization arbitration inhibiting the starting of the thermal engine (10) according to an inhibition request generated during the piloting of a robotic system (12), the method comprising the detection of a first start-up inhibition request (RQ1) emitted by the robotic system (12), characterized in that it further comprises a second request to inhibition (Tin) of the starting of the heat engine (10) triggered from the instant of detection (t0). Control method according to Claim 1, characterized in that the second inhibition request (Tin) is a time delay of a predetermined duration. Control method according to Claim 2, characterized in that the predetermined duration is between 500ms and 1500ms. Control method according to any one of Claims 1 to 3, characterized in that the first inhibition request (RQ1) is generated at the instant (t0) of triggering of a parking brake application/release command robotized. Control method according to any one of Claims 1 to 3, characterized in that the first inhibition request (RQ1) is generated at the instant of triggering of an opening/closing command for a motorized element of a vehicle door. Motor vehicle comprising a heat engine (10), a means of starting the heat engine (13), at least one robotized system (12), an electrical power supply means (17) and an arbitration means (21) capable of inhibit the starting of the thermal engine (10) according to an inhibition request generated during the piloting of the robotic system (12), characterized in that the arbitration means (21) is configured to implement the method of start control according to any one of claims 1 to 5. Motor vehicle according to Claim 6, characterized in that the electrical power supply means (17) comprises a battery (14) and in that the starting means (13) and the robotized system (12) are powered solely by the voltage delivered by the battery (14). Motor vehicle according to Claim 6 or 7, characterized in that a first robotic system (12) is a parking brake system with motorized callipers. Motor vehicle according to any one of Claims 6 to 8, characterized in that a second robotic system is a door system comprising a motorized element. Motor vehicle according to any one of Claims 6 to 9, characterized in that the starting means (13) is an automatic stop and restart system starter.