FR2790427A1 - Control method for hybrid parallel drive for motor vehicle involves controlling motor cut off and drive selection dependent on operating parameters - Google Patents

Abstract

The control method for a hybrid parallel traction drive for a motor vehicle involves selectively coupling an internal combustion engine (MT) and an electric motor (ME) to the primary (1) or secondary (2) transmission shafts of a gearbox (BV). The method involves cutting of the engine, changing the gears and the selective coupling dependent on the vehicle operating parameters.

Description

Control method of a traction system of the "parallel hybrid" type

  The present invention relates to a method of controlling a traction system of the "parallel hybrid" type, in particular for a motor vehicle, and to a

  device for implementing this method.

  Patent application FR-9816130, filed in the name of the applicant, discloses a traction system of the "parallel hybrid" type comprising (see FIG. 1 of the attached drawing): a) a mechanical drivetrain comprising an MT heat engine a transmission system such as a robotic gearbox BV comprising at least one primary transmission shaft 1 that can be mechanically coupled to said motor MT by means such as an EB clutch and at least one secondary transmission shaft 2 which can be mechanically coupled to said primary transmission shaft 1 for driving at least one wheel 3 of said vehicle, and b) an electric machine ME operating as a motor or alternator, which can selectively combine its mechanical power with that of said mechanical power train, or use at least part of the mechanical power of this chain to recharge electrical energy storage means such as batteries 4, said electric machine ME being selectively mechanically coupled to said primary transmission shaft 1 or to said transmission shaft

secondary 2.

  It is provided in the patent application FR-9816130 that this system can be controlled by a computer

  digital electronics duly programmed 5.

  The present invention relates in the first place to a control method of this system intended to be implemented.

by this calculator.

  According to an essential characteristic of this method, it is necessary to start and stop said heat engine, the reduction ratio changes of said gearbox and the selective coupling of said electric machine to said primary or secondary transmission shafts. function of predetermined parameters representative of the operation of said vehicle. According to other characteristics of this method: - it is checked whether said parameters meet or not certain predefined criteria before appropriately controlling the components of said mechanical power train and said electric machine, said parameters comprise, with respect to the control of the start-up and shutdown of said heat engine and changes in reduction ratio: the torque demand of the wheel formulated by the driver of said vehicle, the speed of this vehicle, and the state of said battery, said parameters comprise, with regard to the control of the selective coupling of said electric machine to said primary or secondary transmission shafts: the speed of said vehicle, - according to a first variant, this method comprises the following successive steps when said vehicle evolves from a situation where it is stopped to a situation where it is traveling at high speed (and vice versa): starting said thermal engine, the first reduction ratio being engaged and said electric machine being coupled to said primary transmission shaft; disconnecting said electric machine from said primary transmission shaft and coupling it to said secondary transmission shaft, and - changes in the reduction ratio, - according to a second variant, this method comprises the following successive steps when said vehicle moves from a situation where it is stopped to a situation where it runs at high speed (and conversely ): - starting of said heat engine, one of the reduction ratios being engaged and said electric machine being coupled to said secondary transmission shaft, - upward changes in the reduction ratio, and - uncoupling of said electric machine from said transmission shaft secondary and coupling of this machine to said shaft

primary transmission.

  The present invention also relates to a

  device for implementing this method.

  According to an essential characteristic, this device comprises a supervisor relying, in order to implement this method, on the knowledge of the values of various parameters, in particular: - on the torque demand to the wheel as it is formulated by the depressing an accelerator pedal by the driver of said vehicle, - on the speed of the vehicle as supplied by a tachometer, and - on the condition of the battery as supplied by a controller. battery, said supervisor acting on said engine, on said clutch, on said gearbox and on said electric machine by

  the development of appropriate control signals.

  According to another characteristic of this device, said supervisor also relies on knowledge of a mode instruction as provided by a

mode selector.

  The present invention also relates to a motor vehicle, remarkable in that it is equipped

of the above-mentioned device.

  Thanks to these characteristics, a method and a device for implementing this method are obtained making it possible to optimize the energy balance and the comfort of use of a "hybrid" traction system.

  parallel "of the type described in patent application FR-

9816130.

  Other features and advantages of this method and device will be apparent in light of the

  description which follows and on examination of the annexed drawing,

  in which: - Figure 1 shows a traction system

  in accordance with the teaching of the patent application FR-

  9816130, as well as the device for carrying out the method according to the invention in order to control this system, - Figure 2 is a block diagram describing a first variant of the method according to the invention, and - Figure 3 is a block diagram describing a

  second variant of the method according to the invention.

  In these figures, identical references denote identical or similar organs or sets of members. Referring now to Figure 1, already mentioned

  in the preamble of this description.

  The device for implementing the method according to the invention comprises the calculator

  5, called in the following "supervisor".

  This supervisor relies on the knowledge of the values of various parameters, in particular on the demand for torque to the wheel as it is formulated by the depression y of an accelerator pedal 6 by the driver of the vehicle, on the speed V of the vehicle as provided by a tachometer 8, on the state E (charge, temperature, voltage, current, maximum power and minimum power ...) of the battery 4 as supplied by a battery controller 10, and a mode setpoint C as provided by a

  mode selector 12 operated by the driver.

  The supervisor 5 acts on the heat engine MT, on the clutch EB, on the gearbox BV and on the electric machine ME by the development of signaling signals.

  appropriate control, respectively a, CER, CBV, CE.

  Referring now to Figure 2, describing a first variant of the method according to the invention. In this figure, which must be read in parallel with Figure 1 described above, each block indicates the state of the heat engine MT (ON = ON, OFF = stopped), the transmission shaft of the gearbox BV on which is coupled the electric machine ME (primary or secondary), and the reduction ratio RA of the gearbox BV (first, second, third or fourth in the illustrative and non-limiting case of a four-speed gearbox) . In what follows, it will be said that a criterion CR1 for starting up the heat engine MT or a criterion CR2 for stopping this engine is satisfied if the supervisor 5 estimates, particularly from the torque demand y, of the speed V of the vehicle and the state E of the battery 4, which must respectively be switched on or off

MT heat engine.

  In practice, this type of decision can be implemented with predefined tables adapted to each vehicle and integrated into the supervisor 5. Block 20 corresponds to a start-up situation

or stopping the vehicle.

  When starting the vehicle, we start with

  check if criterion CR1 is satisfied.

  If this is the case, that is to say for example if the battery 4 is to be recharged, the gearbox BV is in neutral, the clutch EB is engaged, and the thermal engine MT is started by the electric machine ME coupled with the primary transmission shaft 1 which then functions as a starter. Once the MT heat engine has been started, it can recharge the battery 4 by rotating the machine

  ME electric which works then alternator.

  If the criterion CR1 is not satisfied, that is to say for example if the battery 4 is sufficiently charged, the clutch EB is disengaged and the thermal engine MT is not started. The electric machine ME is coupled to the primary transmission shaft 1, and the first reduction ratio is engaged. The vehicle is running in "all electric" mode, that is to say it is powered only by the electric machine ME

operating as a motor.

  While driving in "all electric" mode, the CR1 criterion is still monitored to detect,

  eventually, the moment when he becomes satisfied.

  If such a moment occurs (arrow 21), for example because it is necessary to recharge the battery 4, the clutch EB

  is engaged and the heat engine MT is started.

  Meanwhile, the electric machine ME remains coupled to the primary transmission shaft 1, and the

  first reduction ratio remains committed (block 22).

  In any case, once the criterion CRI is satisfied and that the thermal engine MT is started, the vehicle can roll: - either in "all thermal" mode, in which it is powered by the single heat engine MT, the electric machine ME running idle, - either in "hybrid" mode, in which it is powered by both the thermal engine MT and the electric machine ME operating as a motor, - or still in "hybrid with charging" mode, in which it is powered by the single heat engine MT, the electric machine ME operating as an alternator

to charge the battery 4.

  The switchover from one of these modes to another is made according to the demand for torque y and

the state E of the battery 4.

  When the speed V of the vehicle increases and exceeds a predefined value V2 from any of the preceding situations (arrows 23 and 24), the electric machine ME is uncoupled from the primary transmission shaft 1 and is coupled to the secondary drive shaft 2. Meanwhile, the MT engine continues to propel the vehicle through the first gear

reduction (block 25).

  If the vehicle speed V continues to increase (arrow 26), the supervisor 5 controls upshifts RA ratio. During these gear changes, the electric machine ME continues to propel the vehicle via the secondary transmission shaft 2

(block 27).

  When the vehicle is in the situation of the block 22 and the criterion CR2 stopping the thermal engine MT is satisfied (arrow 28), that is to say for example when the battery 4 is sufficiently recharged, the clutch EB is disengaged, the heat engine MT is stopped and the vehicle is traveling in "all electric" mode (block 29). If, when driving in this mode, criterion CR1 is satisfied (arrow 30), the heat engine MT is restarted and the vehicle returns to the situation of the

block 22.

  When the vehicle is in the situation of the block 25 and its speed V falls below a preset speed V1 (V1 <V2) (arrow 31), the electric machine ME is uncoupled from the secondary transmission shaft 2 and is coupled to the primary transmission shaft 1. Meanwhile, the thermal engine MT continues to propel the vehicle via the first reduction ratio (block 32). If, when driving in this mode, the vehicle speed V rises above the preset speed V2 (arrow 33), the vehicle returns to the

Block 25 situation.

  When the vehicle is in the situation of the block 27 and its speed V decreases and / or the torque demand y and / or the state E of the battery 4 requires it, the supervisor 5 controls changes descendants of reduction ratio (arrow 34). During these gear changes, the electric machine ME continues to propel the vehicle via the secondary transmission shaft 2 (block 35). Of course, if it is necessary, the supervisor 5 can, from the situation of the block 35, again control the amount of reduction ratio changes for

  return to the situation of block 27.

  When the supervisor 5 has commanded the gearbox BV to downshift first and the speed V of the vehicle drops below the preset speed Vl (arrow 36), the electric machine ME is uncoupled from the secondary transmission shaft 2 and is coupled to the primary drive shaft 1:

  is in the situation of Block 32 described above.

  before. If, from this situation, the CR2 stopping criterion of the thermal engine MT is satisfied (arrow 37), this engine is stopped and the vehicle is traveling in "all electric" mode: we find ourselves in the situation of the block

29 described above.

  The vehicle can be stopped in a number of different ways depending on the situation in which it is

is initially.

  When it is in the situation of the block 22 and the CR2 stopping criterion of the thermal engine MT is not satisfied, that is to say for example if the battery 4 must be recharged, the heat engine MT continue to propel the vehicle until it stops (arrow 38). Once the vehicle is stopped (block 20), the gearbox BV goes into neutral and, if necessary, the engine MT can continue to

  operate to charge the battery 4.

  When the vehicle is in the situation of the block 29, it can be stopped simply by canceling the speed of rotation of the electric machine ME which operates in motor (arrow 39), the clutch EB being

  disengaged and the thermal engine MT is stopped.

  When the vehicle is in the situation of the block 32 and the CR2 stopping criterion of the thermal engine MT is not satisfied, it can also continue to be

  powered by this engine until it stops (arrow 40).

  Referring now to Figure 3, describing a

  second variant of the method according to the invention.

  In what follows, we will strive to use the same references as before, but with the sign "'" (prime), to emphasize the analogy that exists

between these two variants.

  When starting the vehicle, we first check whether a criterion CR1 ', defined in a similar way to CR1, is satisfied. If this is the case, the gearbox BV is in the neutral position, the clutch EB is engaged, and the thermal engine MT is started by the electric machine ME coupled with the primary transmission shaft 1 which

then works as a starter.

  If criterion CR1 'is not satisfied, the gearbox BV is in neutral, the clutch EB is

  disengaged and the MT heat engine is not started.

  The electric machine ME is coupled to the secondary transmission shaft 2. The vehicle is running in "all electric" mode, that is to say it is powered only

  by the electric machine ME operating as a motor.

  During driving in "all electric" mode, CR1 'is continued to be monitored to detect,

  eventually, the moment when he becomes satisfied.

  If such a moment occurs (arrow 21 '), one of the reduction ratios RA is engaged, the clutch EB is

  engaged and the MT heat engine is started.

  Meanwhile, the electric machine ME remains coupled to the secondary shaft 2 (block 22 '). The choice of the reduction ratio is made as a function, in particular, of the torque demand y, of the speed V of the vehicle,

and state E of the battery 4.

  As in the first variant, once the criterion CR1 'is satisfied and the heat engine MT is started, the vehicle can operate in one of three modes: "all thermal", "hybrid"

and "hybrid with recharge".

  When the speed V of the vehicle increases from any of the previous situations (arrows il 23 'and 24'), the supervisor 5 controls upshifts of reduction ratio RA. During these gear changes, the electric machine ME continues to propel the vehicle via the secondary transmission shaft 2 (block 25 '). If the speed V of the vehicle continues to increase (arrow 26 '), the electric machine ME is uncoupled from the secondary transmission shaft 2 and is coupled to the primary transmission shaft 1. Meanwhile, the heat engine MT continues to propel the vehicle via

  the fourth reduction ratio (block 27 ').

  When the vehicle is in the situation of the block 22 'and a criterion CR2' for stopping the heat engine MT is satisfied (arrow 28 '), the clutch EB is disengaged, the heat engine MT is stopped and the

  vehicle is traveling in "all electric" mode (block 29 ').

  If, when driving in this mode, the criterion CRi 'is satisfied (arrow 30'), the heat engine MT is restarted and the vehicle returns to the situation of the block

22 '.

  When the vehicle is in the situation of the block 25 'and its speed V decreases and / or the torque demand y and / or the state E of the battery 4 requires it (s), the supervisor 5 controls change

  descendants of reduction ratio RA (arrow 31 ').

  During these gear changes, the electric machine ME continues to propel the vehicle via the secondary transmission shaft 2 (block 32 '). Of course, if this proves necessary, the supervisor 5 can, from the situation of the block 32 ', again order changes in the reduction ratio for

  return to the situation of block 25 '.

  When the vehicle is in the situation of the block 27 'and its speed V falls below a predetermined speed Vi' (arrow 33 '), the electric machine ME is uncoupled from the primary transmission shaft 1 and is coupled to the secondary transmission shaft 2. Meanwhile, the thermal engine MT continues to propel the vehicle via the fourth reduction ratio (block 35 '). If, when driving in this mode, the speed V of the vehicle rises above a preset speed V2 '(V2'> Vi '- arrow 34'), the

  vehicle returns to the situation of block 27 '.

  If, from the situation of the block 35 ', the speed V continues to decrease, the supervisor 5 controls downward changes in the reduction ratio RA (arrow 36'). During these gear changes, the electric machine ME continues to propel the vehicle

  via the secondary transmission shaft 2 (block 32 ').

  If, from this situation, the criterion CR2 'for stopping the heat engine MT is satisfied (arrow 37'), this engine is stopped and the vehicle is traveling in "all electric" mode: we find ourselves in the situation of

block 29 'described above.

  The various modes of stopping the vehicle from the situations of the blocks 22 ', 29' and 32 'are similar to those described above in the context of the first variant. In the two variants described above, the driver can intervene at any time to impose a functioning of the vehicle according to the mode of his choice: "any thermal", "hybrid" or "hybrid with recharge". It is enough for it to manually vary the setpoint C using the mode selector

12 (see Figure 1).

  As can be understood at present, the control method according to the invention makes it possible to optimize the energy balance and the comfort of use of a "parallel hybrid" traction system of the type described in the patent application FR-9816130 that is to say of the type comprising an electric machine that can be selectively coupled to a primary transmission shaft or to a transmission secondary transmission shaft. In the two variants presented above, this control method makes it possible to start up the heat engine MT without being penalized by the efficiency of the gearbox BV, given the possibility of direct coupling on the primary transmission shaft of the transmission.

  the electric machine ME operating as a starter.

  In these two variants also, the regenerative braking (that is to say the braking to recharge the battery 4) can be optimized, given the possibility of direct coupling on the secondary transmission shaft of the electric machine ME

operating alternator.

  Moreover, in these two variants, the control method according to the invention makes it possible to keep the secondary transmission shaft permanently under torque, in particular during the reduction ratio changes and during the decoupling of the electric machine ME from

  one of the two trees to mate with the other tree.

  In these two variants, the electric machine ME operating as a motor drives the secondary transmission shaft during the upward passages.

reduction ratio.

  In the first variant, the passage of the electric machine ME from the primary transmission shaft to the secondary transmission shaft and vice versa takes place while the first reduction ratio

is engaged.

  In the second variant, the passage of the electric machine ME from the primary shaft to the secondary shaft and vice versa takes place during the fourth report.

discount is engaged.

  It follows from these provisions that the driver of the vehicle does not feel any acceleration jump during the transition from one operating phase to another of the traction system controlled by the method according to the invention. Of course, the invention is not limited to the embodiments described and represented, provided to

  as an illustrative and non-limiting example.

Claims (9)

  1. A method for controlling a traction system of the "parallel hybrid" type, in particular for a motor vehicle, comprising: a) a mechanical drivetrain comprising a heat engine (MT), a transmission system such as a transmission box; robotized speeds (BV) comprising at least one primary transmission shaft (1) mechanically coupled to said motor (MT) by means such as a clutch (EB) and at least one secondary transmission shaft (2) which can be coupled mechanically to said primary transmission shaft (1) for driving at least one wheel (3) of said vehicle, and b) an electric machine (ME) operating as a motor or alternator, which can selectively combine its mechanical power with that of said traction chain mechanical, or use at least a portion of the mechanical power of this chain to recharge electrical energy storage means such as batteries (4), said electric machine (ME) being selectively mechanically coupled to said primary transmission shaft (1) or to said secondary transmission shaft (2), this method being characterized in that it consists in controlling the start-up and shutdown of said heat engine (MT), the reduction ratio (RA) changes of said gearbox (BV) and the selective coupling of said electric machine (ME) to said primary (1) or secondary (2) transmission shafts according to predetermined parameters (y, LIVES)   representative of the operation of said vehicle.   2. Method according to claim 1, characterized in that it verifies whether said parameters (y, V, E) meet or not certain predefined criteria (CR1, CR2; CR1 ', CR2') before appropriately controlling the components of said mechanical power train and said electric machine ME.   3. Method according to one of claims i or 2,   characterized in that said parameters comprise, with respect to control of the start-up and shutdown of said heat engine (MT) and changes in reduction ratio (RA): the torque demand (y) formulated by the driver of the said vehicle, the speed (V)   of this vehicle, and the state (E) of said battery (4).   4. Method according to any one of the claims   1 to 3, characterized in that said parameters comprise, with regard to the control of the selective coupling of said electric machine (ME) to said primary (1) or secondary (2) transmission shafts: the speed (V) of said vehicle.   5. Process according to any one of the claims   preceding, characterized in that it comprises the following successive steps when said vehicle moves from a situation where it is stopped to a situation where it rolls at high speed (and vice versa): - startup of said engine thermal (MT), the first reduction ratio (RA) being engaged and said electric machine (ME) being coupled to said primary transmission shaft (1), - uncoupling of said electric machine (ME) from said primary transmission shaft (1) and coupling this machine to said secondary transmission shaft (2), and   - changes in the reduction ratio (RA).   6. Process according to any one of the claims   1 to 4, characterized in that it comprises the following successive steps when said vehicle moves from a situation where it is stopped to a situation where it rolls at high speed (and conversely): - getting started said heat engine (MT), one of the reduction ratios (RA) being engaged and said electric machine (ME) being coupled to said secondary transmission shaft (2), - upshifts of the reduction ratio (RA), and - uncoupling said electric machine (ME) from said secondary transmission shaft (2) and coupling said machine to said transmission shaft primary (1).   7. Device for implementing the compliant process   in any one of the preceding claims,   characterized in that it comprises a supervisor (5) relying, for implementing this method, on the knowledge of the values of various parameters, in particular: - on the torque demand to the wheel as it is formulated by depressing (y) an accelerator pedal (6) by the driver of said vehicle, - the speed (V) of the vehicle as supplied by a tachometer (8), and - on the state (E) of said battery (4) as supplied by a battery controller (10), said supervisor (5) acting on said heat engine (MT), on said clutch (EB), on said battery box (4) (BV) and on said electric machine (ME) by generating appropriate control signals (a, CEB, CBV, CME).   8. Device according to claim 7, characterized in that said supervisor (5) also relies on the knowledge of a mode instruction (C) as it is   provided by a mode selector (12).   9. Motor vehicle, characterized in that it is   equipped with the device according to one of the claims 7 or 8.