FR3052813A1 - METHOD FOR RECALING AN ESTIMATION OF A SYNCHRONIZATION REGIME OF A STARTER WITH A MOTOR SPEED DURING A RESTART - Google Patents

Abstract

The invention relates to a method of resetting a synchronization rate estimate of a starter with a motor speed made by a measured armature voltage value, a relationship being established between a rise time (t1, t2, t3) in the starter speed and a starter speed (N1, N2, N3) estimated to be reached at the end of this rise, the rise time (t1, t2, t3) being adjusted for each start. A recalibration is made on said relation by estimation from a measured voltage value of the starter speed (N1, N2, N3) reached for the adjusted rise time (t1, t2, t3) and comparison of the speed (N1, N2, N3) actually reached with the target regime, with adjustment of the rise time (t1, t2, t3) for a subsequent restart when the regime (N1, N2, N3) reached is different from the target regime.

Description

METHOD FOR RECALING AN ESTIMATION OF A SYNCHRONIZATION REGIME OF A STARTER WITH A MOTOR SPEED DURING A RESTART

The invention relates to a resetting process, according to a present state of a starter of a heat engine, an estimate of a starter synchronization speed with a current engine speed when a restart. The invention finds a particularly advantageous application for a motor vehicle engine, the motor vehicle being equipped with a system for automatically stopping and restarting the engine.

An automatic stop and restart system of a motor vehicle engine, also known as the English name "STOP and START System" or the abbreviation STT, consists, under conditions defined in function of the power train, to automatically cause the complete shutdown of the engine, and then automatically restart the engine when a driver action interpreted as a request for restarting the vehicle is detected.

Such an automatic stop and restart system may comprise an electronic device, advantageously housed under a front wing of the motor vehicle. The electronic device comprises a capacitor unit and a device for maintaining voltage and switching, this electronic device being associated with a starter performing, if necessary, the restart of the engine.

Such a starter has an electric motor for rotating the engine and engagement means with the engine. In general, the engagement means are in the form of a pinion carried by the starter meshing in a ring carried by the engine being integral with a flywheel.

[0005] There are several types of starter. For a first type of starter, a single command is sufficient to engage the starter gear in the crown and start the starter motor. When this command is activated, a coil is excited, which will translate the pinion on the crown. The activated command closes a power supply circuit of the electric motor and the electric motor of the starter will drive the engine.

For a second type of starter, particularly suitable for an automatic stop and restart system, it may be advantageous to use a controlled engagement starter which consists in pre-engaging the starter gear in the crown of to minimize the time taken to restart the engine.

[0007] Compared to a conventional starter, a controlled engagement starter generally uses an additional coil which controls the power supply of the electric motor. The starter is then activated by two successive commands: a starter gear engagement command in the crown followed by a motor control allowing the power supply of the electric motor of the starter. Thus, depending on the restart phase, the starter is rotated and then engaged during the synchronization of the regimes. This type of restart follows a mode called ballistic mode.

Such starter controlled engagement can also be a double solenoid starter. An example of a double solenoid starter is given in FR-A-2 971 554.

[0009] A ballistic mode is particularly appropriate when the driver changes his mind and for example restarts just after stopping the engine, the engine still running. The starter is launched in ballistic mode and then stopped to synchronize the starter gear with the crown of the engine.

The synchronization of the regimes is done without speed sensor, but by estimating the speed of the starter in free fall thanks to the measurement of the voltage induced in the starter. The ballistic method, however, does not adapt to changes in the behavior of the starter, in case of aging for example.

Therefore, the problem underlying the invention is to reset a starter according to the association of the starter revving period and target speed to achieve taking into account the evolution over time characteristics of the starter.

To achieve this objective, it is provided according to the invention a resetting process, according to a present state of a starter of a heat engine, an estimate of a starter synchronization regime with a motor speed in force during a restart, the estimate being made by supplying and then cutting off the power supply of an electric motor of the starter respectively causing a rise and a free fall of the speed of the starter, a value of voltage of induced being measured during the free fall and the end-of-climb rating of the starter being estimated as a function of the measured voltage value, a relationship being established between a starting-up period of the starter and a starter speed estimated to be reached at the end of this climb, the rise time being adjusted for each start for synchronization of a target speed of the starter at a current engine speed, characteristics in that a readjustment is made on the climb time relationship with respect to the starter speed by estimation from a measured voltage value of the starter speed actually reached for the adjusted climb time and comparison of the actual speed reached with the target regime, with adjustment of the rise time for a subsequent restart when the actual regime reached is different from the target regime.

The technical effect is to adapt a restart ballistic mode to variations in the characteristics of the starter, because of its aging and / or damage, so as to ensure optimized performance throughout the life of the starter in the vehicle.

According to the state of the art, there was a lack of adaptability of the method of obtaining a target starter regime by a rise in revs aging time of the starter. The method of obtaining such a motor speed according to the state of the art was calibrated on a new starter, while the characteristics of a starter evolve during its lifetime. This resulted in a problem of inconsistency between the previously known starter characteristics and the characteristics of the starter at the present time, a problem that the present invention has solved.

Advantageously, there is established a nominal map associating a rise time at a starter target speed, the mapping being recaled by associating the rise time with a starter speed actually reached for this rise time, the starter speed. actually achieved replacing the target starter scheme.

Mapping is the best instrument to combine various ramp up times according to different target regimes to achieve and most easily exploitable by a control starter control. This makes it possible to have a cartography closer to the characteristics at the moment of the starter and thus to have a better synchronization of the regimes in the time. This makes it possible in particular to take into account the aging of the starter which has an influence on the association duration of revving and target speed to reach.

Advantageously, the first step of the method is to associate a ramp-up time with an estimate of the speed of the starter by means of a measured voltage value with use of the nominal mapping giving a rise time. according to a starter target regime, the second step consisting of a comparison of a ramp-up time association and a starter target speed of the nominal mapping with a new association of the climb time and the starter speed actually reached, the duration the climb is the same for the two associations and the third step consists in establishing a mapping recaled by taking the actually reached starter regime as the target regime for this climb time, the failed map replacing the nominal map.

Advantageously, when a new starter replaces the starter for which a map has been established and, where appropriate, recaled, this map is replaced by a map established for the new starter. The after sales flow allows, if necessary, to start from the nominal cartography. It can be updated to adapt to the physical modifications of the starter. When the starter is replaced, an after-sales flow will make it possible to return to the nominal mapping. Advantageously, the starting speed Ndem and the induced voltage U are linked by the formula: U = K.2π. Ndem / 60 in which K is a constant.

The method of resetting the nominal map is preferably, in particular only, implemented after each restart for which the driver has changed his mind, given the circumstances, and ask for a start after an engine stop, automatic or not.

The invention relates to a control command of a starter of a heat engine comprising elements for receiving a voltage induced by an electric starter motor and a thermal engine speed, estimation elements. of a starter speed as a function of a voltage induced by the electric starter motor, elements for calculating a starting-up period of the starter to reach a target speed which is a function of the speed of the received heat engine and storage means of associations of a ramp-up duration of the starter at a target speed to be reached by the starter, characterized in that it implements such a resetting method, the control control comprising resetting elements of the duration associations starting up the starter at a target speed based on a new estimate of the starter speed obtained for the same rise time than that associated with the target diet.

The invention also relates to a motor vehicle starter comprising a pinion intended to be geared with a ring of a flywheel of a heat engine, the starter comprising an electric motor for a startup of the starter and comprising a induced voltage sensor, characterized in that it is equipped with such control command.

From the estimate of the speed of the starter at the end of the ballistic fire and the time taken to reach this regime, the associations are recalibrated, advantageously in the form of a map, duration of the revving and revving to reach, the duration being a function of the regime. This makes it possible to take into account the aging effects of the starter and to keep a good engagement accuracy of a starter gear in a ring of the engine throughout the life of the starter.

Finally, the invention relates to a motor vehicle having a heat engine with a flywheel and a ring, characterized in that it comprises such a starter, the ring being coupled with the starter gear during a restart of the vehicle automobile.

[0025] Advantageously, the motor vehicle comprises an automatic stop and restart system.

Other features, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the accompanying drawings given by way of non-limiting examples and in which: - Figure 1 is a schematic representation of three curves of starter speed as a function of time and with three different ramp-up times, these combinations of rise time and starter speed that can be taken into account in the context of the present invention; FIG. a schematic representation of three starter speed curves giving the same speed value with three different rise times, each curve corresponding to a starter having different characteristics due for example to aging or damage to the starter that can take into account the according to the present invention, - Figure 3 is a representation of a synchronization curve of a starter speed with a speed of the associated engine, the synchronization can be done after a registration according to the present invention.

It is to be borne in mind that the figures are given by way of examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention.

In what follows, it is referred to all the figures taken in combination. When reference is made to one or more specific figures, these figures are to be taken in combination with the other figures for the recognition of the designated reference numerals.

Referring to all the figures in the following, the present invention relates to a method of resetting, according to a present state of a starter of a heat engine, an estimate of a speed of Starter synchronization with engine speed in effect during a restart.

It is to the various states due to aging to degradation that takes a starter in his life that the present invention intends to apply the resetting process. The present state qualifies the state of the starter at the time of implementation of the resetting process. The rise time is shorter when the starter has aged because the brushes wear out. The springs that put them in contact with the collector are therefore less compressed, so there is less friction: the rotor rotates more freely.

The Ndém starter regime, N1, N2, N3 is not measured but estimated. This estimate is made by supplying and then cutting off the power supply of an electric motor of the starter respectively causing a rise and a free fall of the starter speed Ndém, N1, N2, N3. An armature voltage value is measured during the free fall and the speed of the starter Ndem, N1, N2, N3 at the end of rise is estimated as a function of the measured voltage value.

Referring in particular to Figures 1 and 2 and Figure 3 for Nmot reference, the starter comprises an electric motor electrically powered for a rise time t1, t2, t3, t rev. Then, the power supply is cut off, the starter then operating in free fall. It can be estimated that at the end of the rise time t1, t2, t3, t in regime, the estimated speed must be close to the Nmot speed of the engine. The speed of the starter Ndem, N1, N2, N3 can therefore be simply determined from the armature voltage. This is done by powering the starter and then cutting the power supply and then measuring the armature voltage when the starter operates in free fall, this after the rise time t1, t2, t3, t rev.

If it is desired to engage the starter with the engine, it is possible to compare the values of the two engine speeds and starter and when they are equal, we can then proceed to this commitment.

A relationship is established between a rise time t1, t2, t3, t in the starter regime and a starter speed Ndém, N1, N2, N3 estimated to be reached at the end of this rise, the rise time t1 , t2, t3, t being adjusted for each start for synchronization of a starter target speed at a current engine speed.

Referring in particular to Figure 1, it is shown three target modes of the starter to achieve, the three curves giving the starter regime N1, N2, N3 as a function of time t. These target regimes are reached at three different rise times t1, t2, t3, the highest regime requiring the longest duration and the lowest regime the lowest duration. The target speed corresponds to the engine speed of a thermal engine running during a restart.

According to the invention, a resetting is done on the rise time relation t1, t2, t3, with respect to a Ndém starter regime, N1, N2, N3 by estimation from a measured voltage value of speed of the starter Ndém, N1, N2, N3 actually reached for the rise time t1, t2, t3 adjusted and comparison of the speed Ndém, N1, N2, N3 actually reached with the target speed, with adjustment of the rise time t1, t2, t3 for a subsequent restart when the Ndém regime, N1, N2, N3 actually reached is different from the target regime.

Referring in particular to Figure 2 which gives the Ndem regime as a function of time t, it can be seen that, for the same target regime, there can be three different ramp-up times for obtaining this target diet. Assuming that the average curve is the target regime in relation to the rise time t revised by a nominal mapping, this mapping will have to be corrected by substituting for the rightmost curve a longer revving and for the curve the further to the left, a shorter climb.

Referring in particular to Figures 1 and 2, a start control control associated with the starter, being informed that the starter must reach a desired target speed which is that of the engine that will be in effect at the restart, will search in the duration of rise associations t1, t2, t3, t revs and target mode the desired target speed and will see what rise time t1, t2, t3, t regime this target regime corresponds to implement a restart with a such rise time t1, t2, t3, t in regime. If the rise duration associations t1, t2, t3, t and target regime are accurate, then the desired target regime will be obtained.

It can be established a nominal map associating a rise time t1, t2, t3, t at a starter target speed. The mapping may be recalculated by associating the rise time t1, t2, t3, t with a starter speed effectively reached for this rise time t1, t2, t3, t, the actual starter speed that is used to replace the starter target speed. . If the start control command is informed that the target speed is reached before or after the rise time t1, t2, t3, t in revs, the control will decrease or increase this duration to obtain the desired target speed.

Thus, we can reset all associations rise time t1, t2, t3, t rev in a target regime for, when we want to obtain a starter target regime that is close to Nmot regime referenced in Figure 3 of engine, to go up for a period of time identified to reach such a target speed of the starter.

The first step of the method may be to associate a rise time t1, t2, t3, t in revs to an estimate of the speed of the starter Ndém, N1, N2, N3 via a voltage value. measured using the nominal mapping giving a rise time t1, t2, t3, t according to a starter target speed. The nominal mapping is not done by measuring the starter voltage but by vendor data or table tests by painting targets on a starter rotor and using an optical sensor to determine its speed. of rotation.

The second step may consist of a comparison of a rise time association t1, t2, t3, t in regime and starter target speed of the nominal mapping with a new association rise time t1, t2, t3, t and starter speed actually reached, the rise time t1, t2, t3, t being the same for the two associations.

Finally, the third step may consist in establishing a fixed mapping by taking the regime of the starter Ndém, N1, N2, N3 actually reached as the target regime for this rise time t1, t2, t3, t, the recaled mapping replacing the nominal mapping.

Referring in particular to Figure 3, this figure shows the engine speed Nmot dotted which decreases sharply since this period is a period before restart, the engine is no longer fueled. If a restart is requested, the starter goes into ballistic mode with an increase in its speed which is referenced Ndém to differentiate it from the Nmot engine speed of the engine.

At the end of the launch of the starter in ballistic mode, the launch being referenced 1 in Figure 3, it is possible to estimate the speed of the starter Ndém in free fall, the free fall of the regime being referenced 2, this thanks to a measurement of the induced voltage of the starter.

We can then estimate the end-of-climb speed of the starter and readjust the mapping associating the ramp-up time to the target speed of the starter, the rise time being a function of the target speed while also knowing the duration of activation of the starter. starter.

The meshing of the starter with the engine which is made by a starter gear meshing in a fixed crown of a flywheel of the engine is referenced 3 in this figure.

When a new starter replaces the starter for which a map has been established and, if appropriate, this map can be replaced by mapping established for the new starter. Each starter can present a map specific for its type, age and / or use profile. As previously mentioned, when replacing the starter an after-sales flow will return to the nominal mapping.

The Ndem starting speed and the armature voltage U may be linked by the formula:

in which K is a constant.

The method can be implemented after a predetermined number of successive starts or restarts or a number of kilometers traveled. It is then considered plausible that the starter has aged and that the combination of ramp-up time and target speed reached has varied from that memorized in the map.

We can remove the need to update if we accept a degradation in the time of the restart service with engine always running. The risk is to miss the synchronization of the regimes because if the starting speed exceeds that of the engine, the synchronization can not be done because the engine speed decreases less quickly than the engine speed. Otherwise, a closed-loop control of the starter can be provided. However, this requires a speed sensor to be able to measure the starting speed in its rise phase.

Referring to all the figures, the invention relates to a control command of a starter of a heat engine. The control control comprises elements for receiving a voltage induced by an electric starter motor. The control command communicates with an engine control to obtain the Nmot speed of the engine and incidentally its decay profile when the engine no longer works.

The control system also comprises elements for estimating a starter speed as a function of a voltage induced by the electric starter motor, calculation elements with a rise time t1, t2, t3, t in speed of the starter to reach a target speed based on the Nmot regime of the received thermal engine and association storage means with a rise time t1, t2, t3, t in the Ndem, N1, N2, N3 starter regime at a target regime to be reached by the starter.

Such control control of the starter can implement a method as previously described. In this case, the control control includes elements for resetting the up-time associations t1, t2, t3, t in the Ndem, N1, N2, N3 starter regime at a target speed according to a new estimation of the speed of rotation. starter obtained for the same rise time t1, t2, t3, t in regime than that associated with the target regime.

The invention also relates to a motor vehicle starter comprising a pinion intended to be geared with a ring of a flywheel of a heat engine and having an electric motor for a revving of the engine, the starter comprising a sensor of an induced voltage. This starter is equipped with such a control command as previously described.

Finally, the invention relates to a motor vehicle having a heat engine with a flywheel and a crown. The motor vehicle comprises a starter as described above, the heat engine crown being coupled with the starter gear during a restart of the motor vehicle.

The motor vehicle may include an automatic stop and restart system. Indeed, it is with this type of vehicle that a restart can be done with a heat engine still running so at a non-zero speed. In this case, the starter must be brought to a regime similar to the engine speed so that its pinion meshes with a fixed crown of the engine.

The motor vehicle may be a hybrid vehicle, preferably a semi-hybrid vehicle. A semi-hybrid vehicle is also known as mild-hybrid and is a vehicle equipped with a thermal engine and a low power electric motor.

The motor vehicle can also be provided with a kinetic energy recovery system, for example braking or during a descent, the electric motor then operating as a generator. This recovered energy provides additional power at low speed or during a phase of strong acceleration.

The invention is not limited to the described and illustrated embodiments which have been given only as examples.

Claims (9)

1. Method of resetting, according to a present state of a starter of a heat engine, an estimate of a starter synchronization speed with a current engine speed during a restart, the estimate by supplying and then disconnecting the power supply of an electric motor of the starter respectively causing a rise and a free fall of the speed of the starter (Ndém, N1, N2, N3), a value of armature voltage being measured during the free fall and the speed of the starter (Ndém, N1, N2, N3) at the end of the rise being estimated as a function of the measured voltage value, a relation being established between a rise time (t1, t2, t3, t) in starter speed and a starter speed (Ndem, N1, N2, N3) estimated to be reached at the end of this rise, the rise time (t1, t2, t3, t) being adjusted for each start for a synchronization of a target diet of the starter to a diet of the mote ur in force, characterized in that a registration is made on the relationship rise time (t1, t2, t3, t) with respect to the starter speed (Ndém, N1, N2, N3) by estimation from a measured voltage value of the starter speed (Ndém, N1, N2, N3) actually achieved for the adjusted rise time (t1, t2, t3, t) and comparison of the speed (Ndém, N1, N2, N3) actually achieved with the target regime, with adjustment of the rise time (t1, t2, t3, t) for a subsequent restart when the regime (Ndém, N1, N2, N3) actually reached is different from the target regime. 2. Method according to claim 1, wherein there is established a nominal map associating a running time (t1, t2, t3, t) in revs at a starter target speed, the mapping being recaled by associating the duration of rise ( t1, t2, t3, t) at a starter speed effectively reached for this rise time (t1, t2, t3, t), the actual starter speed that is used to replace the starter target speed. 3. Method according to claim 2, wherein the first step of the method is to associate a rise time (t1, t2, t3, t) in revs to an estimate of the speed of the starter (Ndém, N1, N2, N3) via a measured voltage value using the nominal mapping giving a rise time (t1, t2, t3, t) as a function of a starter target speed, the second step consisting of a comparison of a rise time association (t1, t2, t3, t) in regime and starter target speed of the nominal mapping with a new association climb time (t1, t2, t3, t) and starter speed actually reached, the duration of rise (t1, t2, t3, t) being the same for the two associations and the third step consisting in establishing a mapping reset by taking the regime of the starter (Ndém, N1, N2, N3) effectively reached as regime target for this rise time (t1, t2, t3 , t), the recaled cartography replacing the nominal cartography. 4. Method according to any one of claims 2 or 3, wherein, when a new starter replaces the starter for which a map has been established and, where appropriate reset, this map is replaced by a map established for the new starter . 5. Method according to any one of the preceding claims, wherein the starter speed Ndem and the armature voltage U are linked by the formula: U = K.2tt. Ndem / 60 in which K is a constant. 6. Control command of a starter of a heat engine comprising elements for receiving a voltage induced by an electric starter motor and a speed (Nmot) of the heat engine, elements for estimating a starter speed as a function of an induced voltage of the electric starter motor, calculation elements of a rise time (t1, t2, t3, t) in the starter mode (Ndém, N1, N2, N3) to reach a target regime depending on the speed (Nmot) of the received heat engine and means for storing associations of the duration of a rise (t1, t2, t3, t) in the starter's speed at a target speed to be reached by the starter, characterized in that it implements a method according to any one of the preceding claims, the control control comprising recalibration elements of the associations of rise time (t1, t2, t3, t) in the regime of the starter at a speed target according to u a new estimate of the starter speed obtained for the same rise time (t1, t2, t3, t) in regime than that associated with the target speed. 7. Motor vehicle starter comprising a pinion intended to be meshing with a ring of a flywheel of a heat engine, the starter comprising an electric motor for a starting of the starter and comprising a sensor of an induced voltage, characterized in that it is equipped with a control device according to claim 6. 8. Motor vehicle having a heat engine with a flywheel and a ring, characterized in that it comprises a starter according to claim 7, the ring being coupled with the starter gear during a restart of the motor vehicle. 9. Motor vehicle according to claim 8, which comprises an automatic stop and restart system.