FR2791928A1 - Engine and motor stop sequence control method for a parallel hybrid vehicle, has a central control supervisor controlling inverter, gearbox, clutch and butterfly valve assemblies - Google Patents

Abstract

The dive train assembly comprises of a central controller/supervisor (1) that receives a control input signal from an acceleration pedal (9). The controller assembly controls the inverter (6) and butterfly valve (3) of the motor and engine respectively. In addition, the controller also controls the clutch (4) and gearbox (7) operation. All the variables are controlled by the controller relative to the position of the accelerator pedal.

Description

Method for keeping a vehicle stationary.

  The present invention is applicable to any vehicle having an electric motor connected to the wheels and a mechanical locking mechanism. It is in particular applicable to electric vehicles, parallel hybrids having a robotic gearbox. The operation can be done with a planetary gear train linked to a heat engine and an alternator with a locking finger as on a

  classic automatic gearbox.

  To keep a vehicle stationary, various systems exist to date. In the case of an automatic gearbox, a pretensioning torque is permanently applied by the gearbox to the wheels. This always slightly positive torque causes a slight permanent advancement of the vehicle if the driver releases the brakes. It is therefore not strictly speaking a means of

hold stationary.

  Mechanical systems, based on automatic brake actuators, allow a vehicle to be frozen. However, these systems

are very costly.

  Finally, the documents US Pat. No. 5,726,890 and US Pat. No. 5,376,869 describe a means for locking an electric vehicle on the spot by using more or less direct position regulation, either directly by position regulation, or by torque regulation, or by a request for zero speed. However, to keep a vehicle stationary on a slope, it is necessary to ask a strong torque to the engine and therefore to dimension it in a significant way compared to what should be without this constraint and to support an electrical consumption.

also important.

  The object of the present invention is to remedy the

disadvantages of the prior art.

  The subject of the present invention is a method of keeping an electrically propelled vehicle stationary, an economical method avoiding oversizing of the electric motor and a

electrical overconsumption.

  The method of holding stationary, according to the invention, is intended for a vehicle with electric or hybrid propulsion, of the type comprising a propulsion assembly provided with an electric motor, a battery, and a supervisor. When a speed close to zero is detected and there is no action by the driver on the accelerator pedal, the supervisor causes the vehicle to come to a complete stop by

  emission of a zero speed reference to the electric motor.

  Then, if the total stop time maintained by the electric motor exceeds a predetermined ceiling, or if the vehicle continues to move, the supervisor activates a mechanical locking means of

  the propulsion unit output shaft.

  Advantageously, the vehicle is kept stationary as long as an instruction from the driver does not require driving. In one embodiment of the invention, the vehicle is kept stationary as long as the torque required to keep the vehicle stationary is greater than the torque requested by the driver

  via the accelerator pedal.

  In one embodiment of the invention, the supervisor activates the mechanical locking means of the output shaft of the propulsion unit, also if the power of the battery is

  below a predetermined threshold.

  In one embodiment of the invention, the supervisor activates the mechanical locking means of the output shaft of

  the power train, also if the driver cuts the ignition.

  Advantageously, for a vehicle with parallel hybrid propulsion comprising a heat engine and a gearbox, the mechanical locking takes place by stopping the heat engine and setting

  gearbox in the slowest gear ratio.

  In one embodiment of the invention, the gearbox being controlled by the supervisor, the gearbox is engaged by cutting off the electrical supply to said gearbox, and the uncoupling s 'performs in

  electrically supplying said gearbox.

  In one embodiment of the invention, the mechanical blocking is carried out by actuation of a blocking finger of the

vehicle transmission.

  Thus, the invention makes it possible to size the electric propulsion motor only for driving. The vehicle locking function is carried out at no additional cost and is only based on the control of the electric motor by the taxi supervisor and this is transparent to the driver who has nothing special to do. He just presses the brake to slow the vehicle down and accelerates to restart it. The present invention will be better understood and others

  advantages will appear on reading the detailed description of a

  embodiment taken by way of nonlimiting example, illustrated by the appended drawings in which: FIG. 1 is a general diagram of the architecture of the propulsion unit of a vehicle; FIG. 2 is a view showing the stages of piloting the heat engine and the gearbox in the case of a hybrid vehicle; and FIG. 3 is a view showing the stages of piloting

the gearbox.

  As can be seen in FIG. 1, a supervisor 1 is intended to manage the various organs of a propulsion unit of a hybrid propulsion vehicle. The propulsion unit includes a heat engine 2 fitted with a motorized throttle valve 3 connected to the supervisor 1, a clutch 4 controlled by the supervisor 1, an electric motor 5 powered by an inverter 6 also connected to the supervisor 1, a gearbox 7 connected to the supervisor and intended to drive the wheels 8, only one of which is shown. An accelerator pedal 9

  which can be operated by the driver is connected to supervisor 1.

  The inverter 6 is also connected to a traction battery 10

  controlled by a battery manager 11.

  The gearbox 7 comprises a primary shaft 12 connected to the heat engine 2 via the clutch 4, and a secondary shaft 13 connected at one end to the electric motor 5 and at the other end to the wheels 8 by the intermediary of conventional organs such as a differential. The gearbox 7 includes a plurality of transmission ratios between the primary shaft 12 and the secondary shaft 13. This architecture is said to be parallel hybrid, that is to say that the vehicle can be driven by the electric motor 5 only, the clutch 4 being in the disengaged position, both in acceleration and in braking. The vehicle can also be driven by the heat engine 2 alone, the electric motor 5 neither supplying nor taking torque from the secondary shaft 13, or even simultaneously by the heat engine 2 and by the electric motor 5. When braking, one can foresee that the two motors take torque. When accelerating or maintaining stabilized speed, it is possible to provide that the heat engine 2 provides torque while the electric motor 5 can

  bring or take some for the purpose of recharging the battery 10.

  When the taxi supervisor 1 detects a speed close to zero, he causes the vehicle to come to a complete stop. This detected speed can be a primary speed, a vehicle speed or an electric motor speed 5. The complete stop can be obtained by different means depending on the way in which the propulsion unit is controlled. By way of example, provision can be made to control the electric motor 5 in speed with a zero setpoint. Simultaneously, the heat engine 2 is kept at idle and is disengaged from the gearbox 7. Thus only the electric motor 5 participates in the blocking of the vehicle. If the maintenance lasts too long, or if this first locking mode is insufficient, the vehicle continuing to move forwards or backwards, the supervisor 1 controls the stopping of the heat engine 2 and the clutch on the first gear ratio 7. The vehicle is therefore blocked in the same way as a driver would do with a vehicle with a mechanical gearbox when he leaves it in the first gear engaged parking position. This blocking is done automatically and transparently for the driver who does not

  does not have a gear change command.

  Supervisor 1 keeps the vehicle stationary as long as an instruction from the driver does not require the vehicle to run. Preferably, the blocking ends when the driver presses on the accelerator 9. Supervisor 1 then releases the vehicle. In the case of a gearbox controlled by the driver, the blocking mode is exited when the driver actuates the lever

of speeds.

  However, when the vehicle is on a steep slope and the driver begins to press the accelerator, the requested torque is lower than the holding torque of the vehicle. Thus, the vehicle can start to reverse while the desired direction of travel is forward, and vice versa. The driver is therefore not exempt from using the handbrake to start.

by rating.

  In a preferred variant, the vehicle is kept stationary as long as the driver's command is less than the holding torque or the holding torque is applied directly in addition to the requested torque. To do this, you need to know the holding torque. Its determination can be carried out by speed regulation by a torque control. However, this solution accumulates a certain

  number of sampling delays, which can cause

  wheel knocks. We can also ask the inverter 6 to provide the torque applied to the wheels when the electric motor 5 is torque controlled. Finally, another possibility consists in determining the torque of the electric motor 5 by observing the current of the inverter 6. The current is at first approximation an image of the

  torque applied to the electric motor 5.

  In all three cases, the calculation of the applied torque is only feasible if the first shutdown mode is activated, i.e. if the shutdown is obtained by means of an electric motor torque 5. In the second blocking mode by the gearbox 7, the clutch 4 and the heat engine 2, a torque sensor is required at the

  wheel level 8 to know this information.

  Another possibility is to have a mechanical lock of the same type as that present on automatic gearboxes to obtain the blocking mode. Such a mechanism makes it possible not to shut off the heat engine 2 and only to disengage it, saving time and energy by avoiding restarting the heat engine 2. In this variant, the invention is applicable to any type of electric vehicle with or without an internal combustion engine, or

  another series hybrid vehicle.

  If only the first blocking mode is used, the electric motor 5 must retain the entire vehicle. This position regulation, via torque or speed, makes it consume significant energy. This energy is taken from the traction battery 10. It therefore makes the battery 10 continuously capable of supplying this energy, which is not possible with an electric vehicle and not certain with a hybrid vehicle after electric driving. In addition, it is necessary, among other things for temperature resistance, to oversize the electric motor 5 relative to what would be necessary if this function were not implemented in the supervisor. This results in an additional cost of the electric motor 5 and

  by an increase in mass and therefore in overall consumption.

  For these reasons, we pass to the second blocking mode after a

  predetermined duration, for example one minute.

  The validation of the request to keep stationary is carried out according to the following algorithm Constants: Threshold_starting stop = 5 km / h Processing: request_mainting_stop = FALSE_electric_sufficient = FALSE (40 ms) if start_accel_stroke = TRUE if speed_vehicle <Threshold_starting_stop_stop_ request TRUE if electric_lamping engaged = TRUEelectric_insufficient insufficient = TRUE end if end if otherwise if torque request> = holding torque demand_maintain_stop = FALSE_electric-insufficient = FALSE end if end do It must first detect that the driver wishes to block

  the vehicle on site. This function is performed in the procedure below

  above. A blocking of the vehicle is requested if the driver does not press the accelerator, that is to say if begincourse_accel = TRUE and the vehicle speed is sufficiently low, in our example km / h. The blocking request is invalidated if the driver presses the accelerator. In addition, information indicating that the electric lock alone is insufficient to stop the vehicle is generated. Locking is active as long as the torque requested by the driver is less than the holding torque applied by the engine

  electric when alone to maintain the vehicle.

  The maintenance supervision procedure is carried out as follows Constants cDuration_maintien_électrique = 1 min Treatment: demande_maintien_ électrique = FAUX demande_maintien_thermique = FAUX timermaintien = 0 Do (80 ms) if demandemaintien_ STOP = FALSE demand_maintien_ Électrique = FAUX demande_maintienthermique = FAUX timer_maintien 0 TRUE if (timermainien> cDurée_mainien_ Électrique) OR (insufficient_electric_support = TRUE) request_maintien_thermique = TRUE otherwise holding torque = electric torque realizes end if end If the quickest blocking can be done with the electric motor 5. Consequently, any blocking request will be performed first with the electric motor 5. In the case where the electric motor 5 is not sufficient to achieve blocking (lack of battery power, slope too steep ...) or if the demand lasts too long or if the driver cuts the contact, a mechanical blocking request

  by the heat engine 2 and the gearbox 7 is made.

  Locking of the vehicle by means of the electric motor is carried out according to the following procedure Constants: Limited electric dynamics = 50 Nm Thresholdblocking = 100 rpm Local variables ci, whole deviation Electric hold_triggering engaged = FALSE type electric demand = Demand torque demand electric torque = electric torque filter do (40ms) torque_electric_filter> Limitedynamic1electric

  filter_electric_torque = filter_electric_torque -

  electric Limitedynamique_ otherwise if couple_électriquefiltre <Limitedynamique_électrique torque électrique_filtre couple_électriquefiltre = + electric Limitedynamique_ otherwise couple_électrique_filtre = 0 end if if vitesseGME> Seuilblocage typeAdemande_ electrical demand couple_électrique Demande_couple = = = couple_électriquejfiltre otherwise electric typedemande_ Demande_vitesse demande_ vitesse_électrique = 0 end if end do

  The electric motor 5 is asked for zero speed.

  The inverter 6 interprets this command by performing a torque control. This function is performed by deactivating the vehicle blocking procedure. The latter requests the zero speed setpoint, if possible, a position control of the electric motor 5 is produced by the torque control. A protection is provided so as not to activate the blocking if the electric motor 5 rotates too fast at the time of the blocking request. As soon as the request for blocking of the vehicle by the electric motor is no longer validated by the blocking supervision procedure, the blocking function of the

  vehicle is deactivated and the application of the electric torque is activated.

  As can be seen in FIG. 2, starting from a state where the heat engine is stopped, the blocking by the heat engine is activated if the blocking by the heat engine and by the gearbox is requested. Otherwise the thermal block is deactivated. If a demand for thermal power is present and if there is no thermal blocking request, then the thermal engine is started and the demand-decoupling variable takes the value false. We can then use the engine. If one of the two previous conditions is not met, the variable demand-decoupling takes the value true

  and the engine is stopped and then decoupled.

  As can be seen in Figure 3, the transmission is locked by a specific command. After stopping the engine, if it was in operation, the robotic gearbox also called BVR is decoupled to avoid giving the wheels a sudden torque. If the variable o gearbox_request takes the value true, the gearbox shifts to first gear and then the power supply is interrupted, which leaves the gearbox in gear. If the request_block lock variable takes the value false, the gearbox is woken up and re-energized, which causes it to switch to neutral. If the decoupling_demand variable takes the value false, this means that the gearbox is used for driving the vehicle. If one of the two variables uncoupling_request and gearbox_request takes the value true, the gearbox then switches to the decoupled or neutral position. In this position, if the engine is necessary to

  energy management, it can then be started and used normally.

II

Claims (8)

  1. A method of keeping an electric or hybrid propulsion vehicle stationary, of the type comprising a propulsion assembly provided with an electric motor, a battery, and a supervisor, in which, when detection of a speed close to zero and no action by the driver on the accelerator pedal, the supervisor causes the vehicle to come to a complete stop by issuing a zero speed instruction to the electric motor, then , if the total stop time maintained by the electric motor exceeds a predetermined ceiling, or if the vehicle continues to move, the supervisor activates a mechanical locking means of the output shaft of the power package.   2. Method according to claim 1, in which the vehicle is kept stationary as long as an instruction from the   driver does not request taxiing.   3. Method according to claim 1 or 2, wherein the vehicle is kept stationary as long as the torque necessary to keep the vehicle stationary is greater than the torque requested by the   driver via the accelerator pedal.   4. Method according to any one of the claims   previous, in which the supervisor activates the mechanical locking means of the output shaft of the propulsion unit, also   if the battery power is below a predetermined threshold.   5. Method according to any one of the claims   previous, in which the supervisor activates the mechanical locking means of the output shaft of the propulsion unit, also if the driver cuts the ignition.   6. Method according to any one of the claims   above, in which, for a vehicle with parallel hybrid propulsion comprising an internal combustion engine and a gearbox, the mechanical locking is effected by stopping the internal combustion engine and   gearbox in the slowest gear ratio.   7. The method of claim 6, wherein, the gearbox being controlled by the supervisor, the engagement of the gearbox is effected by cutting off the electrical supply of said gearbox, and uncoupling takes place in   electrically supplying said gearbox.   8. Method according to any one of claims   previous, in which the mechanical blocking is done by   actuation of a vehicle transmission locking finger.