FR2992041A1 - Method for checking use of electric motor and thermal motor of power unit of hybrid vehicle i.e. car, involves determining motor to be utilized according to current operating mode of power unit, and current speed of vehicle - Google Patents

Abstract

The method involves determining which of electric motors (ME) and thermal motor (MT) is to be used at a given moment according to a maximum acceleration of the vehicle. The motor that is to be utilized at the given moment is determined according to a current operating mode of a power unit, a current speed of a vehicle (V) i.e. hybrid vehicle, a programmed control speed for a speed monitoring system (SC), and acceleration value that is requested by the speed monitoring system. A torque instruction is received by the speed monitoring system. Independent claims are also included for the following: (1) a device for checking use of an electric motor and a thermal motor of a power unit of a hybrid vehicle (2) a hybrid vehicle.

Description

TECHNICAL FIELD AND DEVICE FOR CONTROLLING THE USE OF THE ELECTRIC AND THERMAL MOTORS OF A HYBRID VEHICLE, ACCORDING TO ACCELERATION DEMANDED BY A SPEED CONTROL SYSTEM The invention relates to vehicles which are said to be hybrid because they comprise a power train comprising a heat engine and at least one electric motor (or machine) associated with energy storage means, and more specifically the control of the use of the thermal and electric engines of such hybrid vehicles. As known to those skilled in the art, some hybrid vehicles, possibly of the automotive type, comprise a speed control system providing a cruise control function and / or a speed limiter function. This type of system is particularly loaded, once activated and programmed with a speed reference by the driver of a vehicle, to determine for the powertrain a torque value which is intended to make the current speed of the vehicle to programmed speed setpoint.

In the presence of such a system, the choice of each engine to be used at a given time is generally based on the current speed of the vehicle, the programmed speed setpoint, the slope of the road, the level of electrical energy stored in the energy storage means, and the mode of operation of the powertrain that has been chosen by the driver. When the system is activated, this type of choice, which aims to minimize the fuel consumption of the engine (in particular depending on the mode of operation of the powertrain chosen by the driver), induces, unfortunately, a management mode of so-called "all-electric" operation (or ZEV ("Zero Emission Vehicle")) which is really not optimal, particularly because it can cause starting or maintenance in operation of the engine that are not necessary. The invention is therefore particularly intended to improve the situation. It proposes for this purpose a method, on the one hand, dedicated to the control of the use of the electric (s) and thermal engines of a powertrain of a hybrid vehicle equipped with a gearbox and a a speed control system with a programmable speed setpoint, and on the other hand, determining among the electric and thermal motors each engine to be used at a given instant according to a maximum acceleration of the vehicle for the operating mode in the course of the powertrain, the current speed of the vehicle, a programmed system speed reference, and an acceleration value requested by the system. Thus, when the speed control system has been activated, it is possible to carry out a robust control of the use of the electric and thermal motors which makes it possible to ensure at least an acceleration of comfort and in all cases a follow-up. permanent speed setpoint chosen by the driver. The control method according to the invention may comprise other features which may be taken separately or in combination, and in particular: it may comprise a step (i) of determining the maximum acceleration of the vehicle for the operating mode in power train course (all electric or otherwise) depending on the gearbox speed being in gear, resistance forces being experienced by the vehicle, and maximum torque offered by the powertrain; in step (i), the resistance forces that are experienced by the vehicle can be determined according to the current speed of the vehicle and the current torque that is provided by the powertrain; The resistance forces experienced by the vehicle may be equal to the sum of an aerodynamic force experienced by the vehicle, a force related to the slope of the track on which the vehicle is traveling, and a rolling force the vehicle on that lane; it may comprise a step (ii) consisting in determining a setpoint acceleration as a function of the acceleration value requested by the system, a maximum setpoint acceleration, itself a function of at least the maximum acceleration of the vehicle for the current mode of operation of the power train; > in step (ii) the maximum setpoint acceleration can be determined as a function of the maximum acceleration of the vehicle for the current mode of operation of the powertrain and a vehicle acceleration of comfort; in step (ii), the acceleration of the comfort of the vehicle can be determined according to the current speed of the vehicle and the programmed speed setpoint of the system; it may comprise a step (iii) consisting in determining a setpoint torque required by the system to satisfy the acceleration value it has requested, as a function of the determined setpoint acceleration, and then to be determined among the electric motors and each motor to be used at the given time as a function of this determined target torque. The invention also proposes a device, on the one hand, dedicated to the control of the use of the electric and thermal engines of a hybrid vehicle equipped with a gearbox and a speed control system with a speed reference. programmable, and, on the other hand, arranged to determine among the electric and thermal engines each engine to be used at a given moment according to a maximum acceleration of the vehicle for the current mode of operation of the powertrain, the speed during the vehicle, a programmed system speed reference, and an acceleration value requested by the system. The invention also proposes a hybrid vehicle, possibly of automotive type, and comprising electric and thermal motors, a gearbox, a speed control system with a programmable speed setpoint, and a control device of the type of that shown here. -before. Other features and advantages of the invention will become apparent upon examination of the following detailed description, and the accompanying drawings, in which: FIG. 1 schematically and functionally illustrates a hybrid vehicle comprising a powertrain, a control system and a power train supervisor equipped with a control device according to the invention, and - Figure 2 illustrates an example of an algorithm for carrying out a control method according to the invention. The object of the invention is to propose a control method, and the associated control device D, intended to enable the control of the use of the electric motors ME and thermal MT of a power unit of a hybrid vehicle. V with BV gearbox and SC speed control system. In the following, it is considered, by way of non-limiting example, that the hybrid vehicle V is automotive type. This is for example a car.

But the invention is not limited to this type of hybrid vehicle. It concerns in fact any type of terrestrial or maritime (or fluvial) or aeronautical hybrid vehicle, having a powertrain comprising at least one heat engine MT and at least one electric engine (or machine) ME coupled to storage means MS energy.

FIG. 1 shows schematically a hybrid vehicle V comprising a freewheeling power unit, a first SG supervisor capable of supervising the operation of the powertrain, a second supervisor SB capable of supervising the operation of the gearbox BV, and a control device D according to the invention.

The powertrain comprises, here, a heat engine MT, an engine shaft AM, at least one electric motor (or machine) ME, a gearbox BV, a main clutch EM, a drive shaft A1, and a freewheel main RL1 mounted between the MT heat engine and the BV gearbox.

In the non-limiting example of FIG. 1, the main freewheel RL1 is installed between the heat engine MT and the main clutch EM. But in an alternative embodiment (not shown) the main freewheel RL1 could be installed between the main clutch EM and the gearbox BV. The thermal engine MT comprises a crankshaft (not shown) which is fixedly attached to the motor shaft AM to drive the latter (AM) in rotation.

The gearbox BV comprises at least one input (or primary) shaft AE and an output shaft AS intended to be coupled to each other. The input shaft AE is designed to receive the engine torque via the main clutch EM. The output shaft AS is intended to receive the engine torque via the input shaft AE in order to communicate it to the transmission shaft AT 1 o to which it is coupled and which is coupled indirectly to the wheels of the vehicle V. The input shaft AE and the output shaft AS each comprise sprockets (not shown) which are intended to participate selectively in the definition of the different selectable speeds of the gearbox BV. It should be noted that the gearbox BV can be automated or not. Therefore, it may be an automatic transmission, a manual gearbox controlled or not, or a double clutch gearbox (or DCT). In the nonlimiting example of FIG. 1, the clutch EM comprises in particular a flywheel VM which is fixedly attached to the drive shaft A1 and a clutch disc DE which is fixedly secured to the drive shaft. AE input. Furthermore, a first pinion or a first coupling wheel RC1 is firmly fixed to the drive shaft A1 and meshes with a second pinion or a second coupling wheel RC2 which is fixedly attached to a shaft A2 which can be driven into position. rotation by the electric motor ME. In addition, the main freewheel RL1 is an all-nothing type secondary clutch, which comprises in particular a first ring (not shown) which is fixedly attached to the drive shaft AM and a second ring (not shown) which is intended to be 30 closely coupled to the drive shaft A1 during each locking of the main freewheel RL1. The main freewheel RL1 is thus suitable for coupling the drive shafts AM and drive Al, and the main clutch EM is adapted to couple the drive shafts Al and AE input. Note that in the non-limiting example illustrated in Figure 1, the powertrain also comprises an electric machine AD which is, for example, an alternator-starter responsible in particular for launching the heat engine MT to allow it to start, including included in the presence of an automatic stop and start control system (or "stop and start"). This alternator-starter AD is responsible for driving in rotation a rotor shaft (or armature) A3 which is here secured to a secondary free wheel RL2 to be coupled on order to a third pinion or 1 o a third wheel. RC3 coupling which permanently meshes a fourth pinion or a fourth RC4 coupling wheel fixedly attached to the motor shaft AM. The operations of the thermal engine MT, the electric motor ME and the alternator-starter AD are controlled by the first supervisor SG 15 which can be in the form of a computer (preferably dedicated). The operation of the gearbox BV is here specifically controlled by the second supervisor SB which can be in the form of a computer (preferably dedicated). It should be noted that this second supervisor SB is generally useful when the gearbox BV is automated. The speed control system SC is a speed regulator and / or a speed limiter. It is in particular charged, when activated by the driver of the vehicle and it has been programmed with a speed setpoint Cv, to determine for the powertrain an acceleration value Acs according to this speed setpoint Cv and of the current speed 25 Vv of the vehicle V. It will be understood that each acceleration value Acs is determined so as to make the current speed Vv of the vehicle V turn towards the speed setpoint Cv programmed by the driver. This system (speed control) SC is for example in the form of a computer (possibly dedicated). As indicated above, the invention proposes to implement in the vehicle V a control method intended, when the (speed control) system SC is activated, to allow an automatic control of the use of the electric motors (s). ) ME and thermal MT so that the programmed speed setpoint Cv is best respected, both during a steady-state regulation phase and during a phase of modification of the speed setpoint Cv. Such a method can be implemented by the control device D.

In the nonlimiting example illustrated in Figure 1, the control device D is part of the first supervisor (powertrain) SG. But this is not obligatory. This (control) device D could indeed be an equipment that is coupled to the first supervisor SG, directly or indirectly. Consequently, the control device D can be implemented in the form of software (or computer or software) modules, or a combination of electronic circuits (or hardware) and software modules. The control method, according to the invention, consists in determining among the electric motors ME and thermal MT each engine to be used at a given instant as a function of a maximum acceleration Amax of the vehicle V for the current operating mode of the vehicle. power train, the current vehicle speed V V, the programmed system speed setpoint Cv of the system SC, and the acceleration value Ac s that has been requested by the activated system S. The maximum acceleration Amax of the vehicle V for the current mode of operation of the powertrain can be determined in a first step (i), for example according to the current speed engaged in the gearbox BV, Fres resists that are experienced by the vehicle V, and maximum torque CGm max that is offered by the 25 powertrain. This maximum torque CGm max is the one that can be immediately supplied to the wheels by the powertrain for the current operating mode of the powertrain. The latter mode is known at every moment by the second supervisor SB and thus communicated by the latter SB to the first supervisor SG. Note that the resistance forces (or resistant forces) Fres can be advantageously determined at the beginning of the first step (i) as a function of the current speed Vv of the vehicle V and the current torque CGM which is provided by the powertrain at the moment considered. The current speed Vv and the current torque CGm are known to the first supervisor SG possibly via the on-board computer of the vehicle.

For example, the resistance forces Fres are equal to the sum of a Faerodynamic aerodynamic force undergone by said vehicle V, a longitudinal force related to the slope of the track on which the vehicle V is traveling, and a force of Bearing of the vehicle V on this track. As known to those skilled in the art, all these efforts are determined at each moment by some calculators of the vehicle V (for example that of the engine, in particular for the slope estimators to pre-position the regulators) according to the current speed Vv and current torque CGM. The relation between the maximum acceleration Amax, the resistance forces Fres and the maximum torque CGM max is given by the fundamental principle of the dynamics: M .Amax = 1 forces, where M is the mass of the vehicle V and forces is the sum of the forces which are applied to the vehicle V at the moment considered, which is given by the relation: forces = C GM max p 20 where R is the radius of the vehicle wheels V. = C Gm max ± Fre s M .RM Amax In the end we obtain: Preferably, the determination of the driving members to be driven and the decision to leave the all-electric operating mode (or ZEV) are not done directly according to the maximum acceleration Amax and the value 25 Ac acceleration (which has been requested by the activated S system). Indeed, it is preferable to previously determine an acceleration of setpoint Acons, in a second step (ii), intermediate. This determination can, for example, be made according to the acceleration value Ac s which has been requested by the system SC, and a maximum acceleration of setpoint Amax cons, which represents the maximum acceleration level available for the control functions / speed limitation of the SC system. This maximum acceleration of the setpoint Amax cons is for example calculated based on at least the maximum acceleration Amax of the vehicle V for the current operating mode of the powertrain, and preferably an acceleration of comfort Aconf of the vehicle V. This maximum acceleration of the setpoint Amax cons corresponds to the maximum between the maximum acceleration Amax available in the current state of the powertrain (in ZEV mode or hybrid mode (thermal and electric engines in operation) and the comfort acceleration Aconf. powertrain can provide an acceleration level that is greater than the Aconf acceleration of comfort, this means that the SC speed control / speed control functions will be able to take advantage of this acceleration level. can, for example, be determined during the second step (ii) according to the current speed Vv of the vehicle ule V and the programmed speed setpoint Cv of the system SC, and more precisely according to the current speed Vv and the difference between the speed reference CV and the current speed Vv. For this purpose, it is possible for example to use a predefined correspondence table (and thus stored in the control device D). It should be noted that this acceleration of comfort Aconf must correspond to the limit acceleration beyond which the service of monitoring the speed setpoint Cv is no longer considered acceptable.

The acceleration of the Acons set point, which is determined in the second step (ii), corresponds to the acceleration Ac s requested by the regulation / speed limitation functions of the system SC, and "saturated" by the maximum setpoint acceleration. Amax cons to ensure a good choice of engine (ME or MT + ME). Note that this Acons setpoint acceleration can go beyond the maximum acceleration that can offer the vehicle V for the current mode of operation of the powertrain. Consequently, in this situation, the requested acceleration Ac s can not be obtained without the use of the heat engine MT. The determination of each engine to be used is then done in a third step (iii). For example, in this third step (iii) (the device D) can begin by determining a setpoint torque Ccons which is actually necessary for the system SC to satisfy the acceleration value Acs that it has requested, depending on the 'Acons setpoint acceleration determined. Here, therefore, the conversion of the set acceleration Acons determined in a set torque Ccons. It will be noted that this setpoint torque Ccons is that which is necessary for the regulation / speed limitation functions of the system SC in order to converge the current speed towards the speed setpoint C. Then, in this third step (iii), one ( the device D) can determine among the electric motors ME and thermal MT each engine to be used at the instant in question according to this determined set torque Ccons. To do this, it is possible (device D) to compare the determined setpoint torque Ccons at the different wheel torques that are actually achievable in the all-electric operating mode (or ZEV), and then decide to use the heat engine MT if the torque setpoint to Ccons wheels is not feasible with the single electric motor ME (ie in ZEV mode). Note that when the torque setpoint Ccons wheels is feasible again in ZEV mode, the start request of the thermal engine MT is no longer made. FIG. 2 schematically illustrates an example of an algorithm that makes it possible to implement a control method according to the invention, and that includes all the three steps (i) to (iii) described above. A first step (i) can begin with a first substep 10 in which (the device D) estimates the resistant forces Fres according to the current speed Vv of the vehicle V and the current torque CGm which is supplied by the powertrain at the moment considered. In a second sub-step 20 of the first step (i) (the device D) calculates the maximum acceleration Amax of the vehicle V for the current operating mode of the powertrain according to the resistant forces Fres and the maximum torque CGm max that is offered by the powertrain.

A second step (ii) can begin with a first sub-step 30 in which (the device D) calculates a comfort acceleration Aconf according to the current speed Vv of the vehicle V and the difference between the speed reference CV and current speed Vv. In a second substep 40 of the second step (ii), the device D calculates a maximum acceleration of the setpoint Amax cons as a function of the maximum acceleration Amax of the vehicle V for the current operating mode of the group. In a third substep 50 of the second step (ii), the device (D) calculates a set acceleration Acons as a function of the acceleration value. Acs that was requested by the SC system and the maximum acceleration of setpoint Amax cons. A third step (iii) can begin with a first substep 60 in which (the device D) calculates a setpoint torque Ccons 20 which is actually necessary for the system SC to satisfy the acceleration value Acs that it has requested. , depending on the set acceleration Acons determined. Finally, in a second substep 70 of the third step (iii), (the device D) chooses from among the electric motors ME and thermal MT 25 each engine to be used at the instant considered as a function of the setpoint torque Ccons determined. Thanks to the invention, when the speed control system has been activated, it is now possible to conduct a robust control of the use of the electric and thermal motors, capable of ensuring at least an acceleration of comfort and in all cases permanent monitoring of the speed setpoint chosen by the driver. Furthermore, the invention relates not only to situations in which the speed regulation is carried out at an already stabilized speed (which makes it possible to avoid the starting / stopping cycles of the engine when this is not necessary), but also the situations in which the driver decides to increase the speed setpoint (which makes it possible to ensure an acceleration of comfort which corresponds to the minimum acceleration necessary to ensure a correct delivery of the monitoring of the speed setpoint chosen by the driver. driver).

Claims (10)

REVENDICATIONS1. Method for controlling the use of the electric (ME) and thermal (MT) motors of a powertrain of a hybrid vehicle (V) equipped with a gearbox (BV) and a speed control system (SC) programmable speed setpoint, characterized in that it consists in determining among said electric motors (ME) and thermal (MT) each engine to be used at a given time as a function of a maximum acceleration 1 o maximum of said vehicle (V) for a current mode of operation of said powertrain, a current speed of said vehicle (V), a programmed speed setpoint of said system (SC), and an acceleration value requested by said system (SC). 2. Method according to claim 1, characterized in that it comprises a step (i) of determining said maximum acceleration of the vehicle (V) for said current mode of operation of the powertrain as a function of the current speed engaged. in said gearbox (BV), resistance forces experienced by said vehicle (V), and a maximum torque offered by said powertrain. 20 3. Method according to claim 2, characterized in that in said step (i) said resistance forces experienced by the vehicle (V) as a function of said current speed of the vehicle (V) and a current torque are determined. provided by said power train. 4. Method according to claim 3, characterized in that said resistance forces experienced by the vehicle (V) are equal to the sum of an aerodynamic force undergone by said vehicle (V), a force related to the slope a track on which said vehicle (V) circulates, and a rolling force of said vehicle (V) on said track. 5. Method according to one of claims 1 to 4, characterized in that it comprises a step (ii) of determining a setpoint acceleration according to said acceleration value requested by the system (SC), d a maximum setpoint acceleration, itself a function of at least said maximum acceleration of the vehicle (V) for the current speed engaged in said gearbox (BV). 6. Method according to claim 5, characterized in that said step (ii) determines said maximum setpoint acceleration as a function of said maximum acceleration of the vehicle (V) for said running mode of said powertrain and a comfort acceleration of said vehicle (V). 7. Method according to claim 6, characterized in that in said step (ii) said acceleration of comfort of the vehicle (V) is determined according to said current speed of the vehicle (V) and said setpoint 1 o programmed speed of the system (SC). 8. Method according to one of claims 5 to 7, characterized in that it comprises a step (iii) of determining a set torque required for said system (SC) to satisfy said acceleration value that it has requested, as a function of said determined setpoint acceleration, then to determine among said electric (ME) and thermal (MT) motors each engine to be used at said given instant as a function of said determined setpoint torque. 9. Device (D) for controlling the use of the electric (ME) and thermal (MT) motors of a hybrid vehicle (V) equipped with a gearbox (BV) and a control system of speed (SC) with programmable speed setpoint, characterized in that it is arranged to determine between said electric (ME) and thermal (MT) engines each engine to be used at a given instant as a function of a maximum acceleration of said vehicle (V) for a current operating mode of said power unit, a current speed of said vehicle (V), a programmed speed setpoint of said system (SC), and an acceleration value requested by said system (SC). 10. Hybrid vehicle (V) comprising electric (ME) and thermal (MT) motors, a gearbox (BV) and a speed control system (SC) with a programmable speed setpoint, characterized in that further comprises a control device (D) according to claim 9.