MONITORING THE OPERATING POINT OF A VEHICLE'S HYBRID POWERTRAIN DURING PRIORITY ENERGY CHARGING

Abstract

A control method is implemented in a vehicle comprising a powertrain consisting of a first, internal combustion engine coupled to a gearbox, and a second, non-thermal engine that recovers energy during movement to recharge an energy storage device. This method includes a step (10-30) in which each operating point of the powertrain is determined as a function of the vehicle's current speed and the sum of a first torque, representing a driver demand to move the vehicle, and a second torque, representing the power that the second engine must recover to prioritize recharging the energy storage device. Figure to be published with the abbreviation: Fig. 2

Description

Title of the invention: CONTROL OF THE OPERATING POINT OF A HYBRID POWERTRAIN OF A VEHICLE DURING PRIORITY ENERGY RECHARGING Technical field of the invention

[0001] The invention relates to vehicles comprising a hybrid powertrain, and more specifically to the control of the operating point of the powertrain when priority recharging of the energy storage device must be carried out.

[0002] Here, the term "hybrid powertrain" means a powertrain (or GMP) comprising a first thermal driving machine coupled to a gearbox offering at least two ratios, and a second non-thermal machine, possibly driving, and recovering energy during a trip to recharge an energy storage device with energy. Furthermore, here, the term "priming machine" means a machine arranged to provide or recover torque to move a vehicle, either alone or in addition to at least one other thermal or non-thermal driving machine. A non-thermal driving machine may, for example, be an electric machine (or motor), a hydraulic machine, a pneumatic (or compressed air) machine, or a flywheel. A thermal driving machine may, for example, be a thermal engine.When the non-thermal prime mover is an electric machine, the energy storage device is a rechargeable battery. State of the art

[0003] Some vehicles include a hybrid powertrain that allows their energy storage device to be recharged by means of their second (non-thermal) machine during a movement phase provided by the torque produced by the power delivered by their first (thermal) prime mover. In this case, the second machine recovers torque to transform it into energy that powers the energy storage device.

[0004] There are currently two types of charging, respectively called priority and non-priority (or load-shedding).

[0005] A priority recharge is triggered when the charge level of the energy storage device is below a minimum threshold and therefore the energy storage device must be recharged to a so-called priority charge level. Currently, this priority recharge corresponds to a priority power which depends on the difference between the current charge level and the priority charge level, and is triggered as a priority in relation to the engine torque requirement (for travel) requested by the vehicle driver. The priority charge level is the minimum charge level to be reached, unlike the non-priority (or unloadable) charging level which is the target level necessarily higher than the priority one. This priority power is defined by a torque setpoint in the reference frame of the crankshaft of the first prime mover, and is therefore delivered by this crankshaft so that the second machine can recover the corresponding torque.

[0006] A non-priority recharge is triggered when the charge level of the energy storage device is significantly higher than the minimum threshold but lower than a target charge level, and therefore it is desired to recharge the energy storage device to a so-called non-priority charge level in an anticipatory manner. Currently, this non-priority recharge corresponds to a non-priority power which depends on the difference between the current charge level and the non-priority charge level, and is triggered in a non-priority manner relative to the engine torque (displacement) requirement requested by the driver of the vehicle. This non-priority power is defined by a torque setpoint in the reference frame of the crankshaft of the first prime mover, and is therefore delivered by this crankshaft so that the second machine can recover the corresponding torque.

[0007] In order for priority or non-priority power to be produced, it is necessary to determine for the powertrain (or GMP) an optimal operating point defining the ratio to be engaged in the gearbox (coupled to the crankshaft (via the clutch) and for example to at least one set of wheels), in particular. Such an optimal operating point is determined as a function of a gear change law having as main variables the torque to be supplied at, for example, the drive wheels (and a function of the torque requested by the driver of the vehicle), the performance level of the first prime mover, the load deviation of the vehicle from a nominal external load, and the current speed of the vehicle.The load difference represents the difference between the external forces applied to the vehicle under so-called "nominal" conditions (flat road, nominal unladen mass) and the forces actually applied taking into account the actual mass, the actual slope, the actual wind, etc.

[0008] A disadvantage of this method of determining optimal operating points is that the first prime mover may be unable to provide the power necessary to satisfy the recharging requirement.

[0009] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0010] It proposes in particular for this purpose a control method intended to be implemented in a vehicle comprising a powertrain comprising a first thermal driving machine coupled to a gearbox offering at least two ratios, and a second non-thermal machine recovering energy during a journey to recharge an energy storage device with energy.

[0011] This control method is characterized by the fact that it comprises a step in which each operating point of the powertrain is determined as a function of a current speed of the vehicle, and of a sum of a first torque, representative of a request from a driver of the vehicle to move the vehicle, and of a second torque representative of a power that the second machine must recover to recharge the energy storage device as a priority.

[0012] Thanks to the invention, the first prime mover is always capable of providing the power necessary to satisfy the recharging requirement.

[0013] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0014] - in its step we can determine the second couple as a function of the speed in course of the vehicle and at least one external parameter chosen from a current slope of a portion of traffic lane on which the vehicle is traveling and a speed vector of a wind outside the vehicle;

[0015] - in its step each operating point can be determined by means of a gear change law defining, for at least vehicle speeds and sums of first and second pairs, gears to be established in the gearbox;

[0016] - in its step the gear change law can define gears to be established in further function of vehicle load deviations from nominal external loads and a performance index of the first prime mover;

[0017] - in its step each load difference can be a function of at least one parameter exterior, chosen from a current slope of a portion of traffic lane on which the vehicle is traveling and a speed vector of a wind outside the vehicle, and / or a mass of the vehicle.

[0018] The invention also provides a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a control method of the type presented above for controlling an operating point of a vehicle powertrain comprising a first thermal engine coupled to a gearbox, offering at least two ratios, and a second non-thermal engine recovering energy during a journey to recharge a device with energy energy storage.

[0019] The invention also proposes a control device intended to equip a vehicle comprising a powertrain comprising a first thermal driving machine coupled to a gearbox offering at least two ratios, and a second non-thermal machine recovering energy during a journey to recharge an energy storage device with energy.

[0020] This control device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting of determining each operating point of the powertrain as a function of a current speed of the vehicle, and of a sum of a first torque, representative of a request from a driver of the vehicle to move the vehicle, and of a second torque representative of the power that the second machine must recover to recharge the energy storage device as a priority.

[0021] The invention also proposes a vehicle, possibly of the automobile type, and comprising, on the one hand, a powertrain comprising a first thermal driving machine coupled to a gearbox offering at least two ratios, and a second non-thermal machine recovering energy during a journey to recharge an energy storage device with energy, and, on the other hand, a control device of the type presented above.

[0022] For example, the second machine may be an electric machine and the energy storage device may be a rechargeable battery. Brief description of the figures

[0023] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0024] [Fig.l] schematically and functionally illustrates a vehicle comprising a hybrid transmission chain and a supervision computer equipped with a control device according to the invention,

[0025] [Fig.2] schematically illustrates an example of an algorithm implementing a control method according to the invention, and

[0026] [Fig.3] schematically and functionally illustrates an exemplary embodiment of a control device according to the invention. Detailed description of the invention

[0027] The invention aims in particular to propose a control method, and an associated DC control device, intended to enable the control of an operating point of a hybrid powertrain of a vehicle V.

[0028] It is recalled that the term “hybrid powertrain” here means a powertrain (or GMP) comprising a first thermal driving machine and coupled to a gearbox offering at least two ratios, and a second machine, non-thermal and recovering energy during a trip to recharge an energy storage device.

[0029] In the following, it is considered, by way of non-limiting example, that the vehicle V is of the automobile type. This is for example a car, as illustrated non-limitingly in [Fig. 1]. But the invention is not limited to this type of vehicle. It in fact relates to any type of vehicle comprising a hybrid GMP transmission chain. Consequently, the invention relates not only to land vehicles, but also to boats and airplanes.

[0030] [Fig.l] schematically shows a vehicle V comprising a hybrid GMP transmission chain, a supervision computer CS capable of supervising (or managing) the operation of the transmission chain, and a control device DC according to the invention.

[0031] The hybrid GMP comprises here, in particular, a first thermal motor machine MM1, a motor shaft AM, a clutch EM, a second non-thermal machine MM2, a gearbox BV, an energy storage device DS, and a transmission shaft AT.

[0032] The first driving machine MM1 is a thermal engine comprising a crankshaft (not shown), fixedly secured to the engine shaft AM in order to drive the latter (AM) in rotation. Furthermore, this first driving machine MM1 is intended to provide a torque, here for at least a first train T1 (here of driving wheels), via the clutch EM, the second machine MM2 and the gearbox BV.

[0033] For example, this first train T1 is located at the front of the vehicle V, and coupled to the transmission shaft AT, preferably, and as illustrated, via a differential (here front) DI. But in a variant this first train T1 could be located at the rear of the vehicle V.

[0034] Here, the clutch EM is responsible, by way of purely illustrative example, for coupling / decoupling the motor shaft AM (coupled to the first driving machine MM1) to / from the second machine MM2, on the order of the supervision computer CS, in order to communicate a torque from the torque produced by the first driving machine MM1. This clutch EM can be of any type.

[0035] The second machine MM2 is coupled to the energy storage device DS in order to supply the latter (DS) with energy. It will be noted that in the example illustrated without limitation this second machine MM2 is a driving machine and therefore can produce torque from the energy supplied by the energy storage device DS. For this purpose, it (MM2) is here also coupled, by way of purely illustrative example, to the output of the clutch EM, to receive the torque that it transmits, and to the primary shaft AP of the gearbox BV, to supply it with torque.

[0036] It should be noted that this second MM2 machine could be installed in other locations of the vehicle, and in particular it could be coupled, via appropriate coupling means, to the second train T2 (here of driving wheels) of the vehicle V, in order to provide it with torque produced from the energy stored in the energy storage device DS. In the example illustrated non-limitingly in [Fig.l] the second train T2 is located at the rear of the vehicle V, but in a variant it could be located at the front of the vehicle V.

[0037] In the following, it is considered, by way of non-limiting example, that the second machine MM2 is an electric machine (or motor). But the invention is not limited to this type of second non-thermal machine. Indeed, the second machine can also be a hydraulic machine, a pneumatic (or compressed air) machine, or a flywheel, for example.

[0038] Due to this last (electrical) choice, the energy storage device DS is a rechargeable battery, for example of the low voltage type (typically 220 V for illustration purposes). But this rechargeable battery DS could be of the medium voltage or high voltage type.

[0039] The primary shaft AP of the gearbox BV is intended, here, to receive the sum of the torque transmitted by the clutch EM and the torque supplied by the second machine MM2.

[0040] The gearbox BV offers at least two ratios. It also comprises at least one secondary shaft (not shown) intended to receive torque via the primary shaft AP in order to communicate it to the transmission shaft AT to which it is coupled and which is here indirectly coupled to the drive wheels (here front) of the vehicle V via the differential DI.

[0041] It will be noted, as illustrated non-limitingly in [Fig.l], that the transmission chain can also comprise a starter or an alternator-starter AD coupled to the first prime mover MM1 and responsible for starting the latter (MM1) in order to allow it to start. This starting is done using electrical energy which is, for example and as illustrated non-limitingly, stored in a service battery BS. The latter (BS) can be arranged in the form of a very low voltage type battery (for example 12 V, 24 V or 48 V), and can also, for example, supply an on-board network to which electrical equipment of the vehicle V is connected.It will be noted that the service battery BS can, as illustrated without limitation, be coupled to the energy storage device DS, when the latter (DS) is a rechargeable battery, and to the second machine MM2 via a DC / DC type CV converter, in order to be able to be recharged when the second machine MM2 is an electric machine.

[0042] The operations of the first MM1 and second MM2 driving machines, the clutch EM and the gearbox BV can be controlled by the computer. CS supervision.

[0043] As mentioned above, the invention proposes a control method intended to enable the control of the operating points of the hybrid powertrain of the vehicle V. This control method can be implemented at least partially by the DC control device of the vehicle V which comprises for this purpose at least one processor PR, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD, and therefore which can be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). The memory MD is RAM in order to store instructions for the implementation by the processor PR of at least part of the control method. The processor PR can comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections.An integrated (or printed) circuit is any type of device capable of performing at least one electrical or electronic operation.

[0044] In the example illustrated non-limitingly in [Fig.l], the DC control device is part of the CS supervision computer. But this is not obligatory. This DC control device could in fact be a piece of equipment comprising its own computer and coupled to the CS supervision computer, directly or indirectly.

[0045] As illustrated non-limitingly in [Fig.2], the control method, according to the invention, comprises a step 10-30 which begins in a sub-step 10 when the vehicle V is in a movement phase ensured by the torque produced by the power delivered by its first driving machine MM1.

[0046] In this sub-step 10 one (the control device DC) begins by determining whether the energy storage device DS must be subject to priority recharging. To do this it can, for example, compare the current charge level of the energy storage device DS to a minimum threshold.

[0047] If not ("no" - and therefore if non-priority recharging can be carried out), the first prime mover MM1 will produce the amount of torque that allows, as far as possible, to at least ensure the driver's wishes plus recharging. If the sum of the two is not achievable by the first prime mover MM1, recharging will be reduced in favor of respecting the driver's wishes. In all cases, the driver's wishes have priority.

[0048] Non-priority charging is therefore opportunistic depending on the capacity of the first driving machine MM1 to ensure it in addition to the driver's request.

[0049] On the other hand, if the answer is yes (“yes” - and therefore if priority recharging is required), the DC control device performs sub-steps 20 and 30 in which it determines the operating point of the powertrain as a function of the current speed vv of the vehicle V, and the sum of a first torque cl, representative of the request of the driver of the vehicle V to move the latter (V), and a second torque c2 representative of the power that the second machine MM2 must recover to recharge the energy storage device DS as a priority. More precisely, in substep 20 the DC control device determines the second torque c2, and in substep 30 the DC control device determines the operating point of the GMP. The first torque cl is for example supplied to the DC control device by the supervision computer CS.

[0050] Thus, thanks to the determined optimal operating point, the first prime mover MM1 is capable of producing, and produces, a total torque equal to cl + c2 which satisfies the priority recharging and the driver's demand, and the second machine MM2 recovers the second torque c2 in this total torque. Consequently, the first prime mover MM1 is always capable of providing the power necessary to satisfy the recharging need.

[0051] It will be noted that in sub-step 20 of step 10-30 one (the control device DC) can determine the second torque c2 as a function of the current speed vv of the vehicle V (or what is equivalent the speed of the wheels) and of at least one external parameter which is chosen from the current slope of the portion of traffic lane on which the vehicle V is traveling and the speed vector of the wind outside the vehicle V.

[0052] The current slope can be provided by map data accessible in the vehicle V or by a tilt sensor fitted to the vehicle V, for example.

[0053] The wind speed vector defines the direction, sense and speed of the wind outside the vehicle V. It is, for example, defined by meteorological information accessible in the vehicle V.

[0054] For example, the DC control device can convert the priority charging requirement (expressed in power) into a second torque c2, for example at the wheels. Then, the DC control device can convert the power (for priority charging) into a second torque c2 as a function of the current speed vv (or the speed of the wheels) and at least one external parameter. It will be noted that this conversion may possibly include a delinearization phase intended to limit, for example, the second torque c2 at low speed. The purpose of the delinearization is to possibly not take into account the priority charging requirement in the calculation of the operating point in order to make the behavior of the vehicle V repeatable, because we are then solely dependent on the driver's wishes.

[0055] It will also be noted that in sub-step 30 of step 10-30 one (the control device DC) can determine each operating point by means of a gear change law which defines, for at least speeds vv of the vehicle V and sums of first c1 and second c2 couples, ratios to be set up in the gearbox BV. For example, one can feed the gear change law with at least the current speed vv of the vehicle V and the sum of the first cl and second c2 couples in order to determine the ratio to be established.

[0056] Since the driver's wishes (or requests) take priority over non-priority recharging, the gear change law is not modified when non-priority recharging is to be triggered, which makes it possible to offer the driver an optimal acoustic level via an adapted speed of the first driving machine MM1.

[0057] This passage law is predetermined in the laboratory or in the factory and stored in the DC control device.

[0058] In the presence of the last option, in sub-step 30 of step 10-30 one (the DC control device) can use a gear change law which defines gears to be set up also as a function of load deviations of the vehicle V compared to nominal external loads and of a performance index of the first driving machine MM1.

[0059] The performance index represents, for example, a ratio between the maximum torque achievable under current conditions and the maximum torque achievable under nominal conditions (altitude / temperature). It is generally known by the CS supervision computer.

[0060] For example, each load difference may be a function of at least one external parameter, chosen from the current slope of the portion of traffic lane on which the vehicle V is traveling and the wind speed vector outside the vehicle V, and / or the mass of the vehicle V.

[0061] The mass of the vehicle V can be provided by a mass sensor fitted to the vehicle V, for example.

[0062] It will be noted, as illustrated non-limitingly in [Fig. 3], that the control device DC can also comprise, in addition to its RAM MD and its processor PR, a mass memory MM, in particular for storing the current values ​​of the variables and parameters (internal and external), any meteorological or cartographic information, and intermediate data involved in all its calculations and processing. Furthermore, this control device DC can also comprise an input interface IE for receiving at least the current values ​​of the variables and parameters (internal and external), and any meteorological or cartographic information for use in calculations or processing, possibly after having formatted and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR'.In addition, this DC control device can also include an IS output interface, in particular for delivering orders, commands and messages (at least for the CS supervision computer).

[0063] It will also be noted that the invention also provides a program product computer (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR, is capable of implementing the control method described above to control an operating point of the powertrain of the vehicle V.

[0064] It will also be noted that one or more sub-steps of the step of the control method can be carried out by different components. Thus, the control method can be implemented by a plurality of digital signal processors, random access memory, mass memory, input interface, output interface.

[0065] The invention allows for homogenization of the behavior of the vehicle V with respect to the level of recharging because this behavior remains mainly dependent on the will of the driver. Only cases of priority recharging lead to a change in the behavior of the vehicle V, at the will of its driver.

Claims

Claims

1. Control method for a vehicle (V) comprising a powertrain comprising a first thermal motor (MM1) coupled to a gearbox (BV) offering at least two ratios, and a second non-thermal machine (MM2) recovering energy during a movement to recharge an energy storage device (DS) with energy, comprising a step (10-30) in which each operating point of said powertrain is determined as a function of a current speed of said vehicle (V), and of a sum of a first torque, representative of a request from a driver of said vehicle to move said vehicle (V), and of a second torque representative of a power that said second machine (MM2) must recover to recharge said energy storage device (DS) as a priority, and of a gear change law defining,for at least speeds of said vehicle (V) and sums of first and second pairs, ratios to be established in said gearbox (BV), characterized in that in said step (10-30) said gear change law defines ratios to be established as a function, in addition, of load deviations of said vehicle (V) compared to nominal external loads and of a performance index of said first prime mover (MM1).,

2. Method according to claim 1, characterized in that in said step (10-30) said second torque is determined as a function of said current speed of the vehicle (V) and at least one external parameter chosen from a current slope of a portion of traffic lane on which said vehicle (V) is traveling and a speed vector of a wind outside said vehicle (V).

3. Method according to claim 1 or 2, characterized in that in said step (10-30) each load difference is a function of at least one external parameter, chosen from a current slope of a portion of traffic lane on which said vehicle (V) is traveling and a speed vector of a wind outside said vehicle (V), and / or a mass of said vehicle (V).

4. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the control method according to one of the preceding claims for controlling an operating point of a motor group. vehicle propulsion system (V) comprising a first thermal motor (MM1) coupled to a gearbox (BV) offering at least two ratios, and a second non-thermal motor (MM2) recovering energy during travel to recharge an energy storage device (DS) with energy.

5. Control device (DC) for a vehicle (V) comprising a powertrain comprising a first thermal motor (MM1) coupled to a gearbox (BV) offering at least two ratios, and a second non-thermal motor (MM2) recovering energy during a journey to recharge an energy storage device (DS), characterized in that it comprises at least one processor (PR) and at least one memory (MD) arranged to carry out the operations consisting of determining each operating point of said powertrain as a function of a current speed of said vehicle (V), and of a sum of a first torque, representative of a request from a driver of said vehicle to move said vehicle (V) with said first motor (MM1),and a second torque representative of the power that said second machine (MM2) must recover to recharge said energy storage device (DS) as a priority, and a gear change law defining, for at least speeds of said vehicle (V) and sums of first and second torques, ratios to be established in said gearbox (BV), said gear change law defining ratios to be established as a function, in addition, of load deviations of said vehicle (V) compared to nominal external loads and of a performance index of said first prime mover (MM1).,

6. Vehicle (V) comprising a powertrain comprising a first thermal engine (MM1) coupled to a gearbox (BV) offering at least two ratios, and a second non-thermal engine (MM2) recovering energy during a journey to recharge an energy storage device (DS) with energy, characterized in that it further comprises a control device (DC) according to claim 5.

7. Vehicle according to claim 6, characterized in that said second machine (MM2) is an electric machine and said energy storage device (DS) is a rechargeable battery.

8. Vehicle according to claim 6 or 7, characterized in that it is of the automobile type.

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