WO2008122731A1

WO2008122731A1 - Device for controlling the starter of an automotive vehicle

Info

Publication number: WO2008122731A1
Application number: PCT/FR2008/050288
Authority: WO
Inventors: Stéphane PLAIDEAU
Original assignee: Valeo Equipements Electriques Moteur
Priority date: 2007-03-16
Filing date: 2008-02-20
Publication date: 2008-10-16
Also published as: FR2913727A1; EP2122155A1; FR2913727B1

Abstract

The invention relates to a control device (10) for controlling the starter of an automotive vehicle, that comprises: a first variable voltage generator (2); an amplifier (3) at the output of the voltage generator; a contactor (1) including an inrush winding (La), a holding winding (Lm) and a power contact (R), the contactor being supplied y the amplifier; and a module (20) for maintaining the power supply of the inrush winding of the contactor once the power contact is closed.

Description

Device for controlling a motor vehicle starter

The present invention relates to a device for controlling a motor vehicle starter. Patent EP-B1 526 307 discloses a device for controlling a motor vehicle starter, comprising a voltage generator, an amplifier and a contactor controlled by a voltage delivered by the amplifier and being able to progressively increase. between lower and upper voltage terminals to prevent too violent propulsion starter starter pinion. The contactor comprises a fixed core and a movable core subjected to the action of call and hold windings. This device further comprises temperature compensation means for increasing the lower voltage terminal above. The contact winding of the contactor is disconnected on closing of the power contact, only the holding winding being electrically powered.

This device is generally satisfactory.

However, when the moving core of the contactor is moved too slowly, it does not have enough kinetic energy, can not happen to magnetic bonding with the fixed core of the contactor, the magnetic bonding corresponding to a zero gap between the cores fixed and mobile.

The present invention aims to overcome this disadvantage.

The invention thus relates to a device for controlling a motor vehicle starter, comprising:

a first variable voltage generator, an amplifier at the output of the voltage generator,

a contactor comprising a call winding, a holding winding and a power contact, the contactor being powered by the amplifier,

- A module for maintaining the power supply of the contact winding of the contactor after closing the power contact. Thanks to the invention, the mobile core is ensured, taking into account the action of the winding, to go to magnetic bonding with the fixed core of the contactor even when its kinetic energy is low, or even zero, after closing the power contact. The power supply of the call winding can last a few milliseconds to a few tens of milliseconds after closing of the power contact.

Among other advantages of the invention, mention may be made of the significant improvement in the kinematics, the limitation of the wear of the front faces of the launcher pinion and the starter ring, the significant improvement in the behavior with respect to re-openings of the power contact and therefore less wear of the contactor terminals.

Preferably, the generator is arranged to make it possible to generate a voltage ramp with a positive or negative slope.

Advantageously, the module comprises a second variable voltage generator, in particular arranged to allow generating a voltage ramp, and a switch.

In an exemplary implementation of the invention, the module comprises an input connected between the contactor and a starter motor, and an output connected between the first voltage generator and the amplifier. If desired, the amplifier comprises a transistor, in particular of the type

MOSFET.

If necessary, the module comprises, in parallel with the second voltage generator and the switch, a maximum potential setting element making it possible to ensure that the transistor of the amplifier is completely switched on after the closing of the power contact. .

In an exemplary implementation of the invention, the maximum potential setting element comprises in series a diode and a resistor.

Advantageously, the device is arranged in such a way as to be able to maintain the power supply of the holding winding after the power supply of the call winding has been cut off. The invention will be better understood on reading the following detailed description, non-limiting examples of implementation of the invention, and on examining the appended drawing, in which:

FIG. 1 is a block diagram illustrating a control device according to a first exemplary implementation of the invention,

FIG. 2 is an electrical diagram of the control device of FIG. 1,

FIGS. 3a to 3c schematically illustrate the variation as a function of time of different parameters for the control device of FIG. 2,

FIG. 4 is a block diagram illustrating a control device according to a second exemplary implementation of the invention,

FIG. 5 is an electrical diagram of the control device of FIG. 4, and FIGS. 6a to 6c schematically illustrate the variation as a function of time of various parameters for the control device of FIG. 5.

Referring first to Figure 1 in which the starter control device 10 comprises a battery B, the negative terminal is connected to the ground by a conductor 11 and whose positive terminal is connected to a movable contact. a start switch K.

When the switch K is closed, the voltage Ub delivered by the battery B is applied to the input of a voltage generator 2 whose output is connected to an amplifier 3 delivering a current la for the control of a contactor 1 , more precisely for the control of an exciter winding L.

The contactor 1 also comprises a power contact R, one of whose terminals is connected to the positive pole of the battery B, and whose other terminal is connected to the electric motor M of the starter.

The winding L is a double winding, having a call winding La and a holding winding Lm as illustrated in FIG. 2. The voltage generator 2 comprises means for varying the control current Ia of the contactor 1.

The control device 10 further comprises a module 20 for maintaining the power supply of the contact winding La of the contactor 1 after closure of the power contact R.

This module 20 comprises a variable voltage generator 24 and a switch 25.

This module 20 comprises an input 26 connected between the contactor 1 and the motor M, and an output 27 connected between the voltage generator 2 and the amplifier 3.

The voltage generator 24 is arranged to create a voltage ramp.

This generator 24 is powered only upon closing of the power contact R.

In the example considered, the generator 24 varies the voltage Ut from 0 V and when a certain voltage threshold is reached, controls the closing of the switch 25 for connecting the input of the amplifier 3 to the mass and thus to obtain Ia = O, namely the end of the supply of the coil call La.

The voltage variation Uc at the output of the generator 2 is represented in the graph of FIG. 3a, on which the time t is plotted on the abscissa and the voltage Uc on the ordinate.

When the switch K (time = 0) closes, the voltage generator 2 is arranged in such a way that the voltage Uc has a value Uo which is lower than the triggering voltage or the connection voltage of the contactor and to be made gradually increase the voltage Uc from its initial value Uo to the conjunction voltage which, for a given operating temperature, is between U0 and the battery voltage Ub.

The positive terminal of the battery B is connected to a first pad of a movable contact of the start switch K controlled conventionally by the ignition key of the vehicle. The other pad of the switch K is connected, on the one hand, via the call winding La to the drain of a MOSFET transistor T1, and on the other hand, to the resistors R1 and R2, the resistor R2 being connected to the ground conductor 1 1.

This pad of the switch K is also connected to the holding winding Lm, which itself is connected to the ground conductor January 1.

A capacitor C1 is interposed in series between the resistors R1 and R2.

The resistors R1 and R2 and the capacitor C1 form the voltage generator 2.

This voltage generator 2 is connected to the gate of transistor T1, which transistor defines, in this example, amplifier 3.

The voltage generator 24 of the module 20 for holding the power supply has a resistor R3 in series with a capacitor C2.

The input 26 of the module 20 is connected to a terminal of the resistor R3.

The switch 25 comprises a MOSFET type transistor T2 whose gate is connected between the capacitor C2 and the resistor R3.

The source of transistor T2 is connected to ground and the drain of transistor T2 to the gate of transistor T1.

The operation of the control device 10 will now be described in greater detail with reference to FIGS. 3a to 3c. At the closing of the switch K, Uc = Uo = R2 / (R1 + R2) Ub, Uo corresponding to the voltage value at which the amplifier 3 begins to pass a current la> 0 (see graphs 3a and 3b).

Alternatively, it is conceivable to have Uo = 0, and in this case, a "dead time" between to and the moment when> 0 can appear. Uc increases and tends asymptotically towards Ub.

The current flowing through the winding increases it as Uc increases.

The movable core of the contactor 1 begins to move, and also the launcher via a lever of the starter. Graph 3c shows the speed V and the kinetic energy E of the starter starter. The instant when the speed V becomes zero corresponds to the moment when the pinion comes against the front face of the crown of the engine.

The launcher therefore no longer moves, but the movable core, thanks to the tooth / tooth spring, continues its movement, until t1 corresponding to the closing of the power contact R.

At t1, Ui goes from 0 to Ub, and the electric motor M is energized.

The voltage generator 24 is also powered and the voltage U increases and tends asymptotically towards Ui.

The shape of the voltage signal Ui depends on the behavior of the electric motor M.

The current consumption of the electric motor M causes the voltage Ui to drop.

The shape of the current signal la between t1 and t2 follows the shape of Ui.

The pinion, thanks to the rotation of the electric motor M, enters the crown of the engine. At t2, Ut reaches the value for which the switch 25 moves from the open state to the closed state.

Thus, the output of the voltage generator 2 is grounded via the switch 25, ie Uc = 0 and thus the = 0.

There remains only the supply of the holding coil Lm and the electric motor M.

FIG. 4 shows a control device differing from the control device described with reference to FIG. 1 in that the voltage-maintaining module 20 'furthermore comprises, in parallel with the voltage generator 24 and the switch 25, a maximum potential setting element 36 making it possible to ensure that the amplifier transistor is fully conducting after the closing of the power contact R to take full advantage of the force of the call winding La.

In the example considered, as illustrated in FIG. 5, the element 36 comprises in series a diode D1 and a resistor R4. The operation of the control device will now be described in more detail with reference to FIGS. 6a to 6c. Between to and t1, the operation is identical to the previous example.

A t1, Ui goes from 0 to Ub, so the electric motor M is powered.

The voltage generator 24 is also powered and the voltage U increases and tends asymptotically towards Ui. The shape of the voltage signal Ui depends on the behavior of the electric motor M.

The current consumption of the electric motor M causes the voltage Ui to drop.

The maximum potential setting module 36 sets the output of the voltage generator 2 to the potential U i (at the voltage drop near the module 36 itself). The amplifier 3 no longer limits the, unlike the previous example, and therefore the is higher.

The shape of the current signal la between t1 and t2 follows the shape of Ui.

The pinion, thanks to the rotation of the electric motor, enters the crown of the engine. At t2, Ut reaches the value for which the switch 25 moves from the open state to the closed state. Thus, the output of the voltage generator 2 is grounded via the switch 25, ie Uc = 0 and thus the = 0.

There remains only the supply of the holding coil Lm and the electric motor M.

Claims

claims

1. Control device (10) for a motor vehicle starter, comprising:

a first variable voltage generator (2),

an amplifier at the output of the voltage generator (3),

a contactor (1) comprising a call winding (La), a holding winding (Lm) and a power contact (R), the contactor being powered by the amplifier,

- A module (20; 20 ') for maintaining the power supply of the contact winding of the contactor after closure of the power contact.

2. Device according to the preceding claim, characterized in that the generator (2) is arranged to allow to generate a voltage ramp with positive or negative slope.

3. Device according to one of the preceding claims, characterized in that the module comprises a second variable voltage generator (24), in particular arranged to allow to generate a voltage ramp, and a switch (25).

4. Device according to the preceding claim, characterized in that the module comprises an input (26) connected between the contactor and a starter motor, and an output (27) connected between the first generator and the amplifier.

5. Device according to any one of the preceding claims, characterized in that the amplifier (3) comprises a transistor (T1), in particular of the MOSFET type.

6. Device according to the preceding claim, characterized in that the module comprises, in parallel with the second voltage generator and the switch, a member (36) for setting the maximum potential to ensure that the transistor (T1 ) of the amplifier is fully on after closing the power contact (R).

7. Device according to claim 6, characterized in that the maximum setting element (36) comprises in series a diode (D1) and a resistor (R4).

8. Device according to any one of the preceding claims, characterized in that it is arranged to be able to maintain the power supply of the holding winding (Lm) after cutting power of the winding of appeal (The).