Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
  • F02N11/00—Starting of engines by means of electric motors
  • F02N11/08—Circuits or control means specially adapted for starting of engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
  • F02N11/00—Starting of engines by means of electric motors
  • F02N11/08—Circuits or control means specially adapted for starting of engines
  • F02N11/087—Details of the switching means in starting circuits, e.g. relays or electronic switches
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
  • F02N2300/00—Control related aspects of engine starting
  • F02N2300/10—Control related aspects of engine starting characterised by the control output, i.e. means or parameters used as a control output or target
  • F02N2300/108—Duty cycle control or pulse width modulation [PWM]

Definitions

• the present invention relates to methods and devices for controlling motor vehicle starters, and more specifically to methods and devices for driving the contactor core of these starters.
• a motor vehicle starter conventionally comprises a contactor 2 as well as an electric motor M, the output shaft of which carries a pinion 1.
• the pinion 1 is intended to cooperate with the gear of the starter ring C of the heat engine. It is sliding on the shaft of the motor M between a position where it is disengaged relative to said starter ring and a position where it meshes with the latter.
• the contactor 2 extends parallel to the electric motor M above the latter and comprises a coil 2a and a plunger core 2b.
• the contactor 2 also controls the movement of the pinion 1. Its plunger core 2b is therefore connected to the pinion 1 by mechanical means referenced by 4 as a whole. These mechanical means comprise a fork coupled at its upper end to the plunger core 2b and at its lower end with a launcher to which the pinion 1 belongs.
• This launcher comprises a freewheel interposed axially between a hub and the pinion 1.
• the hub is internally provided with helical splines engaged in complementary manner with external helical teeth carried locally by the output shaft of the electric motor M.
• the fork is pivotally mounted between its two ends on a casing internally containing the mechanical means 4 and carrying the motor M and the contactor 2.
• the starter with its pinion 1 is driven in a helical movement when it is moved by the fork to engage the starter ring.
• This support has a U-shaped section for housing the winding 2a and therefore has a bottom constituting a pad 2C.
• the core 2b is therefore intended to move between a rest position and a contact position in which it rests on the fixed core, this closed position of the magnetic circuit taking place after closing of the movable contact 3 and therefore of the electrical circuit. .
• the mechanical means also include a return spring mounted around the core 2b to return the latter to the rest position, a cut-off spring associated with the movable contact 3 to return the latter to the open position and a spring 5, called a spring. teeth against teeth, housed inside the core 2b and engaged with a first rod connected by an axis to the upper end of the fork for coupling it to the core 2b.
• This spring 5 has a greater stiffness than the return spring.
• the fork is therefore inserted at its upper end between the core 2b and the axis.
• the first rod mounted inside a blind hole in the core 2b, is intended after a determined stroke to come into engagement with a second rod secured to the movable contact 3 and slidably mounted inside the fixed core.
• the contact 3 In the closed position, the contact 3 cooperates with a fixed contact, in the form of studs connected respectively to the positive terminal of the battery and to the electric motor M, thus enabling the electric motor to be supplied.
• the studs are integral with the closure cover of the contactor made of insulating material.
• the pinion 1 can therefore come into engagement with the crown C, that is to say come into engagement position with the crown C, before the movable contact is closed.
• the mechanical means 4 include in particular a spring 5 which is mechanically interposed between the plunger core 2b and the pinion 1 and which allows the plunger core 2b to continue its travel to ensure, before contact with the fixed core, the positioning of closing of the movable contact, even if the pinion 1 is blocked in abutment against the teeth of the crown of the heat engine, in a position where it does not mesh with this crown.
• a coil B controls both a contactor K and the advancement of a pinion not shown.
• the coil B is supplied via a transistor T in pulse mode, of the pulse width modulation (PWM) type, in French, the transistor being controlled by a microcontroller 10 .
• PWM pulse width modulation
• a cyclic ratio of the pulses is gradually increased to obtain an effective current in the coil which increases progressively.
• This process also aims to reduce the speed of impact of the pinion against the crown to reduce the frontal wear of the latter.
• This document also proposes a device for controlling the supply of a drive coil of a movable core of a motor starter contactor, provided for varying the effective current in the coil during the displacement of the core towards its contact position, in which it is intended to implement during this displacement:
• the object of the present invention is to overcome these drawbacks in a simple and economical manner.
• a method of the above-mentioned type is characterized in that during the second phase, when the movable core is not in the contacting position, a continuous increase is implemented after a determined or predetermined time effective intensity.
• a device of the above-mentioned type is characterized in that during the second phase, provision is made to implement, after a determined or predetermined time, a continuous increase in the effective intensity. Thanks to the invention the contactor has a simple shape and a sudden displacement of the core, from its rest position to its activation position, is avoided.
• the effective intensity in the first interval of the second phase is lower than that of the start of the solution of document FR-A-2 679 717 since the core has already taken off. This reduces noise and the solution is safe.
• the progressive increase in the effective intensity makes it possible, on the one hand, to gradually compress the spring, teeth against teeth 5, and, on the other hand, the closing of the contactor to supply the electric motor in the accidental case where the contactor could not have been closed before.
• the contactor is closed beyond a predetermined or determined time.
• the invention it is nevertheless possible to move the launcher and its pinion.
• the pinion comes into abutment contact with the starter ring, either before increasing the intensity, or after increasing the intensity and before closing the movable contact, so that one sets in motion the electric motor from a zero speed in this stop contact position, which facilitates the penetration of the pinion into the crown while therefore reducing wear.
• the solution according to the invention is therefore reliable and makes it possible to increase the life of the starter thanks in particular to a reduction in wear.
• the solution is economical because the contactor can have only one winding.
• measurements can be made during the first phase.
• This first phase can be broken down into two intervals, namely a first interval with high effective current followed by a second interval with lower current than that of the second phase.
• this second interval is carried out at zero current for better accuracy of the measurement.
• the core can take off with a shorter stroke, the intensity during the first interval of this first phase being close to the intensity necessary to make the core take off and being carried out with a shorter time.
• the winding has a double function because, after a third interval of the second phase, during which it increases the intensity of the effective current, after rotation of the electric motor, it allows the mobile contact to be closed during a third phase.
• the electric motor only turns after the pinion comes into abutment with the crown, so that the pinion can penetrate more easily into the crown and that wear is reduced.
• the time is determined as a function of abnormal values which occur in the event of the mobile contact not being closed.
• the time is determined as a function, for example, of the battery voltage or the winding temperature.
• the time is easily predetermined so that the continuous increase in intensity occurs only when necessary, that is to say so that this time is as short as possible and includes the majority of normal cases of operation .
• FIG. 2 shows a supply arrangement of a starter switch according to the state of the art
• FIG. 3 is a plot showing the evolution of a duty cycle of the supply voltage of a contactor coil, according to the invention.
• Figure 4 is a partial view similar to Figure 3 for another embodiment.
• the plunger core 2b is placed in the bearing 2C in a sliding relationship which is modulated by the presence of a lubricant ensuring a sealing and braking role.
• the core 2b is therefore a mobile core.
• the core has, in its rest position, a force of adhesion to the pad Fa which opposes its setting in motion.
• this force Fa disappears in favor of a friction force Ff, which is much lower than Fa (of the order of 20 to 40% lower).
• the presence of the lubricant does not eliminate these forces. On the contrary, by a gumming effect of the lubricant, it further accentuates the fact that the adhesion force Fa exceeds the friction force Ff.
• the movable core 2b remains at rest as long as the coil 2a does not exert a motive force of attraction Fm which is greater than Fa.
• a device for supplying the coil 2a is used, the mounting of which remains similar to that shown in FIG. 1, and in which a supply of the coil 2a is again adopted according to a niche voltage of the PWM type.
• the duty cycle is varied during the displacement of the core according to the evolution represented in FIG. 3 and this after a predetermined or determined time.
• the call period of the kernel is broken down into two main phases, the second of which is broken down into three sub-phases. We will now describe these two main phases.
• the second phase takes place between time ti and time t 3 .
• the transistor Ti controls the contactor according to a duty cycle having an R2 value substantially equal to 50%, so that the effective current in the coil 2a is significantly reduced compared to that obtained during the first phase, just sufficient to overcome the residual friction forces Ff after takeoff from the core 2b.
• this interval which lasts approximately 30 to 60 ms, the core 2b therefore continues its movement until the contactor closes, without brutality and without excessive speed.
• an abutment contact is obtained between the pinion 1 and the starting ring gear between the times t1 and t2.
• the microcontroller 10 is connected by one of its inputs to a temperature sensor placed inside the contactor 2a in the vicinity of the winding 2b and is also connected by a second input to the supply terminals of the starter.
• the microcontroller 10 takes from these two inputs signals representative of the temperature T of the contactor therefore of the coil 2a and of the supply voltage U at the input of the starter.
• the starter supply voltage is variable depending on the state of charge of the vehicle battery and the temperature. Indeed, the temperature of the coil 2a directly conditions its resistance. However, the average current obtained for a given duty cycle, depends directly on the voltage available at the terminals of the starter - therefore at the terminals of the battery - and on the resistance of the coil 2a.
• the microcontroller 10 includes a memory in which a digital table is recorded, corresponding for an intensity effective efficiency desired, the duty cycle R2 to be adopted as a function of the starter supply voltage and the temperature of the coil.
• R2 is of the order of 0.4 to 0.6 at a temperature of 20 °.
• the effective intensity is substantially constant in this first interval.
• the microcontroller 10 automatically adopts a duty cycle R2 as a function of the supply voltage at the terminals of the starter and of the resistance of the winding (itself dependent on the temperature).
• the measurements of the voltage U and of the temperature T are advantageously carried out before the implementation of the first phase described above, when the starter is activated.
• the microcontroller 10 implements an increase continuous and progressive of the cyclic ratio, going from the R2 ratio to find the R1 ratio or alternatively a ratio greater than R1.
• This interval has a duration of approximately 20 to 50 ms and makes it possible to ensure, by the gradual increase in the effective intensity, the closing of the contactor, in an accidental case where the contactor could not have been closed between t1 and t2.
• Such an accidental case can occur in particular if abnormally high friction forces take place in the contactor, in the mechanical means 4 and at the level of the motor shaft M. These abnormal forces are due for example to climatic phenomena, expansion, seizure, the presence of dirt impurities and all other stains, in particular at the splines of the shaft of the electric motor and the joints of the fork.
• the teeth against teeth spring 5 is compressed to allow the plunger core 2b to actuate the movable contact 3 to supply the electric motor and rotate its shaft in order to ensure penetration of the pinion in the crown and therefore a meshing of the pinion with the crown.
• the mobile contact is closed before this predetermined time as short as possible to include normal operations.
• this time is determined for example as a function of the battery voltage or of the temperature of the coil 2a, these quantities being influenced by the non-closing of the movable contact generating abnormal values.
• the duty cycle is maintained at R1 or at a value greater than R1 for approximately 5 to 30 ms.
• This phase with a high duty cycle begins when the movable contact 3 closes and keeps the core 2b in its contacting position (movable contact 3 closed) with a high attraction force which prevents rebounds of the movable core 2b against a stop usually formed by another nucleus, fix that one.
• This third interval t3, t4 lasts long enough to be able to absorb the current peaks due to the starting of the heat engine by the electric motor M, which according to a characteristic of the invention is not controlled. According to one characteristic, it is therefore only after abutment of the crown with the pinion that the increase in the duty cycle is carried out.
• a cyclic ratio R3 is adopted in a third phase at the terminals of the winding resistance 2a to maintain the movable contact in the closed position.
• the rms current is lower in this third phase than in the other two phases.
• a single coil 2a is necessary and the microcontroller can be mounted on a support, such as a card, in the starter, more precisely be mounted at vicinity of the winding 2a in the space between the movable contact 3 and the cover (not referenced in FIG. 1) carrying the fixed contacts.
• a support such as a card
• the pulse width modulation during the first phase more precisely at the start of this phase, it is possible to measure the current and therefore the voltage of the battery, knowing that, as mentioned above, the average current obtained for a given duty cycle depends directly on the voltage available across the battery.
• the desired duty cycle is adopted.
• the duty cycle R'1 is 100%. In the second interval the duty cycle is lower than the duty cycle R2.
• the duty cycle in the second interval of the first phase is zero for better accuracy of the measurement.
• the effective current during the first interval of the first phase is lower than that of FIG. 3 by being close to it. This effective current is therefore higher than that of the second phase with cyclic ratio R2.
• the duration t 'of the first interval is less than the duration t1.
• the duration t'-t'1 of the second interval is greater than the duration t 'of the first interval. This duration is here more than double that of the first interval and allows a good measurement to be made before the start of the second phase.
• the time t ' is 3 ms and the time of the second interval t'1-t' of 7 ms.
• the current at the end of phase 1 is approximately 3A lower than that in Figure 3.
• the displacement of the core in phase 1 is less than half that of FIG. 1.
• R ' we are in the vicinity of the separation limit of the core.
• the other intervals of the second and third phase have not been shown.
• the device and the method proposed here therefore make it possible to optimize the progressiveness of the movement of the movable core 2b and of the pinion 1. This thus gives an increase in the life of the pinion 1 and of the drive crown as well as a reduction notable noise created by the impact of the pinion against the crown.
• the intensity of the effective current can be reduced in the first phase. It all depends on the displacement of the plunger core that one wishes to have. Compared to the prior art, it is possible to get as close as possible to the separation limit of the core and to better control the displacement of the latter by playing in particular over the duration of the first phase. In the prior art, it is necessary to provide a higher safety factor to be sure that the core takes off.
• the separation of the nucleus is less brutal and is better controlled, the first interval of the second phase occurring at substantially constant effective intensity.
• the microcontroller 10 placed on a card in the aforementioned manner in the vicinity of the coil 2a, it is possible to measure the temperature thereof by mounting on the card a resistor connected to the microcontroller and variable in temperature function for example with positive or negative temperature coefficient.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Relay Circuits (AREA)
• Control Of Direct Current Motors (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1999
  • 1999-06-30 FR FR9908368A patent/FR2795883B1/fr not_active Expired - Lifetime
• 2000
  • 2000-06-28 JP JP2001507931A patent/JP4854894B2/ja not_active Expired - Fee Related
  • 2000-06-28 BR BRPI0006834-9A patent/BR0006834B1/pt not_active IP Right Cessation
  • 2000-06-28 EP EP00946032A patent/EP1108139B1/de not_active Expired - Lifetime
  • 2000-06-28 WO PCT/FR2000/001801 patent/WO2001002722A1/fr active IP Right Grant
  • 2000-06-28 US US09/763,935 patent/US6516767B1/en not_active Expired - Lifetime
  • 2000-06-28 DE DE60010416T patent/DE60010416T2/de not_active Expired - Lifetime
  • 2000-06-28 KR KR1020017002297A patent/KR100687975B1/ko not_active Expired - Fee Related

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