JP2014527138A - Starter circuit of an automobile with a device for raising the battery voltage and a starter provided in this type of circuit - Google Patents

Abstract

  The present invention relates to a starter circuit comprising a combination of a starter and a device for raising battery voltage. The device for raising the battery voltage makes it possible to prevent a drop in battery voltage caused by a current surge that occurs in the starter power circuit when operating the starter. The starter typically has an electric motor and an electromagnetic contactor. According to the present invention, the battery voltage raising device is made of a magnetic material, and the first winding circuit is configured to be inserted in series with the cylindrical head, the two closed portions, and the power circuit therearound. And a magnetic circuit having a shaft center on which the short-circuited second winding circuit is arranged, the shaft center having at least one air gap.

Description

  In general, the invention relates to the field of starters for heat engines in motor vehicles. In particular, the invention relates to a combination of a starter and a device that allows the voltage at the battery terminal of the car to be raised when the starter is switched on.

  When the starter is switched on to ensure start-up of the car's heat engine, there is a substantial demand for a current close to the current level of the starter short circuit, i.e. about 1000A. The intensity of this current requirement when the starter is switched on then decreases as the speed of the starter armature corresponding to the machine rotor increases.

  The resulting voltage drop at the battery terminals corresponds to this initial current surge. Another less substantial voltage drop then occurs during the start-up phase, which corresponds to the continuous top dead center passage of the heat engine.

  Of so-called “enhanced” starters designed for automatic stop / start systems of heat engines (so-called “Stop / Start” or “Stop and Go” systems) The development is now imposing new regulations on auto parts manufacturers relating to compliance with the battery's minimum voltage threshold during current demand when the starter is switched on. Therefore, in those specifications, the automobile manufacturer defines a first voltage threshold that is typically included between 7 and 9V, and the battery voltage should not drop below that. For subsequent voltage drops corresponding to the top dead center of the heat engine, the battery voltage must remain above a second voltage threshold, typically comprised between 8-9V. During start-up of the heat engine, the voltage of the on-board circuitry of the car will therefore remain at a value sufficient to ensure the required function of the car equipment.

  Reinforced starters generally have higher power than conventional starters so as to obtain quick start-up for increased user comfort. This, in connection with the high demand, results in a higher current demand when the power is switched on, and thus a first battery voltage drop that exceeds the usual value. This is because the starter needs to have a very large internal voltage drop to go above the battery voltage, so that there is no longer enough power to drive the heat engine at a sufficient speed at low temperatures. Cause designers difficulty.

  In the prior art, several solutions have been proposed for the problems described above. The first solution known to the inventor is based on the use of an electronic converter that increases the voltage to prevent excessively low voltage levels in the on-board circuitry. The main drawback of these converters is the substantial cost they introduce.

  Another known solution proposes controlling the starter with two relays, a timer, and a current limit resistor. In the first operating phase, whose duration is determined by the timer, an additional resistor is inserted in series with the starter circuit to limit the initial current surge. In the second phase of operation, additional resistors are removed from the starter circuit to allow sufficient current to pass through the starter armature and allow the starter speed to increase.

  The documents EP 2080897A2 and EP2128426A2 describe starters of the type described above. As well as the additional cost disadvantages associated with additional control relays, timers, and current limit resistors, the introduction of additional relays, including moving mechanical parts that are subject to wear, must be able to withstand the starter without difficulty. Has a negative effect on the useful life of the starter with respect to the number of cycles. The service life of the starter with respect to the number of start-up cycles is a particularly severe constraint on starters designed for stop / start systems. In fact, this type of starter is required to withstand about 300,000 start-up cycles, i.e. approximately ten times the 30,000 cycles required by conventional starters.

  In addition to the disadvantages described above, the use of the second solution according to the prior art turns out to be inappropriate when the vehicle manufacturer requires compliance with the voltage range to be limited with respect to time. This type of range generally has a low voltage step corresponding to the first voltage threshold shown above and a high voltage step corresponding to the second voltage threshold. A rising voltage gradient is also included in the range between the low step and the high step.

  The tests performed by the inventor using the manufacturer's conventional values for the low step and slope slope duration of the range exist in this second solution according to the prior art of staying within the range. Shows difficulty. In fact, with the current passing through the starter armature then increased substantially as a result of the output of the current limit register of the starter circuit, the battery voltage is once rectified once the initial current surge has been absorbed. When falling again at the end of the timing, the risk of exceeding the range at the level of the voltage gradient was found. Thus, after exceeding the range, the battery voltage can stay below the range for a certain duration and return to the range only after the end of the rising voltage gradient, whereas the start of the high voltage step The moment has already been reached.

  In order to eliminate the drawbacks described above, the inventor has already proposed improvements to existing starters according to the prior art, especially for automotive applications related to the automatic stop / start function of the heat engine.

  In general, these improvements install an inductive filtering device in series with the electric motor in the starter power circuit to prevent battery voltage drops following current surges caused by operating the electric motor. It is composed of

  New work done by the inventor makes it possible to optimize these improvements embodiments.

  Thus, according to a first aspect, the invention relates to a combination of a starter and a device for raising battery voltage in an electric starter circuit of a motor vehicle, the starter comprising an electric motor and an electromagnetic contactor, and the battery voltage Is designed to prevent the battery voltage drop following the current surge caused by operating the starter in the power circuit.

  According to the invention, the device for raising the battery voltage consists of an inductive filtering device mounted in series with the electric motor in the power circuit, the filling device comprising a cylindrical head and two closed parts. And a housing made of a magnetic material having a first winding circuit around which the first winding circuit is designed to be inserted in series with the power circuit and a short-circuited second winding circuit. It has a magnetic circuit configured and has an axis with at least one air gap.

  According to a first particular embodiment, the at least one air gap is a central air gap.

  According to a second particular embodiment, the at least one air gap has two end air gaps between the closed portions.

  According to a third particular embodiment, the closure parts each have an annular air gap. Preferably, the annular air gap is aligned with the first winding circuit or the second winding circuit in the axial direction.

  According to a particular feature, the second winding circuit consists of a conductive tube. The tube is made of copper or aluminum and has a predetermined length-to-diameter ratio and a predetermined thickness.

  According to another particular embodiment, the filtering device is inserted in the starter power circuit between the positive terminal of the car battery and the power contact of the electromagnetic contactor.

  According to yet another particular embodiment, the filtering device is inserted in the starter power circuit between the power contact of the electromagnetic contactor and the electric motor.

  According to another aspect, the invention also relates to a starter that can be incorporated into a combination as briefly described above. According to the present invention, the filtering device included in the combination is fixed on the outer case of the starter.

  The small number of specifications above will make clear to those skilled in the art additional advantages that can be obtained by optimization by the applicant's company of inductive filtering devices.

  Detailed specifications of the present invention are given in the following description provided in connection with the accompanying drawings. It should be noted that these drawings serve the purpose of merely illustrating explanatory text and do not constitute any limitation of the scope of the invention.

FIG. 1 is a perspective view showing a combination of inductive filtering devices of the type previously developed by the starter and applicant company. FIG. 2 is a process diagram of an electrical starter circuit having a combination as shown in FIG. 3a, 3b and 3c respectively show the electromagnetic flow rate of the filtering device due to the current circulating in the starter power circuit in the case of the filtering device according to the invention (square) and in the case of the conventional filtering device (diamond), respectively. It shows the change in magnetic energy as well as the change in current based on time. FIG. 4 is a cross-sectional view of an inductive filtering device of the type previously developed by the applicant's company. FIG. 5 is an axial cross-sectional view of a filterlin device according to the present invention in a first preferred embodiment. FIG. 6 is an axial sectional view of a filtering device according to the present invention in a second preferred embodiment. 7a and 7b are axial cross-sectional views of an example of a filtering device according to the present invention in a third preferred embodiment.

  FIG. 1 shows a combination 1 of a starter having a DC electric motor DCM and an electromagnetic contactor EC and an inductive filtering device LPF to which an optimization effort by the applicant's company is applied.

  In the present embodiment, the filtering device LPF is mechanically fixed to the outer case of the starter in the vicinity of the contactor EC.

  The electrical connection between the filtering device LPF, the contactor EC and the electric motor DCM is shown in FIG.

  The filtering device LPF is electrically attached in series between the power contact CP of the contactor EC and the motor DCM.

  According to another embodiment (not shown), the filtering device LPF is not integrated with the starter EC, DCM, but is inserted into the power circuit between the positive terminal B + of the battery and the power contact CP. .

  The contactor EC in this case is a conventional starter contactor with a simple power contact CP and has a solenoid formed by a lead-in coil and a holding coil.

  Closing the vehicle start contact CS controls the energization of the lead-in and holding coils and the activation of the starter according to a sequence well known to those skilled in the art and not described in detail here.

  When sufficient power is supplied to the motor DCM, the aforementioned initial current surge occurs at the closing of the power contact CP.

  The closing of the power contact CP also causes a circulation of the current supplied to the motor DCM in the filtering device LPF.

  As shown in the electrical diagram of FIG. 2, the filtering device LPF is in this case an inductive device which in this case takes the form of a double casing type transformer with magnetically coupled windings. It will be noted that, depending on the application, a simple induction resistor can be used to form a low-pass filtering device with which optimization work is relevant. However, embodiments with a transformer allow for having more parameters to tune the frequency response of the device LPF in some applications. It is therefore possible to optimize this response by controlling the inductive resistors of the first and second circuits W1, W2 and the mutual inductance introduced by the coupling between these circuits.

  The first winding circuit W1 is inserted into the power circuit of the starter. The second winding circuit W2 is short-circuited.

  Typically, the equivalent inductance of the inductive filtering device LPF is comprised between about 0.1 and 10 mH for a current having an approximate magnitude of 300-1000A.

  The resulting effect of increasing the battery voltage is that when the motor DCM is switched on, the initial current surge is cut off (approximately half weakened) as a result of the generation of strong current induced in the shorted second circuit W2. It stems from the fact that it counters sudden changes in the electromagnetic flow that produces the induced current.

  FIG. 3a shows the change of the electromagnetic flow Φ in the magnetic circuit of the non-optimized filtering device LPF (diamond curve 2) and in the magnetic circuit of the optimized filtering device LPF according to the invention (square curve 3). Yes.

  In the case of a non-optimized filtering device LPF, the electromagnetic flow Φ increases very rapidly with strength and is stable at a maximum value.

  FIG. 3b shows that this saturation value corresponds to a small accumulation of magnetic energy Em (diamond curve 4).

  As a result, although the current surge is attenuated, as clearly shown in FIG. 3c (diamond curve 5), the current I is very rapid when the saturation of the magnetic circuit of the unoptimized filtering device LPF is reached. To increase.

  In order to delay the occurrence of the saturation phenomenon, the optimized filtering device LPF according to the invention has a magnetic circuit with at least one air gap AG.

  FIG. 3a clearly shows that the electromagnetic flow Φ does not increase more strongly with the current I than when the magnetic circuit does not have an air gap AG (diamond curve 2) (square curve 3). The saturation phenomenon is also less substantial.

  In this case, the stored magnetic energy Em reaches a higher value (square curve 6 in FIG. 3b) than the value corresponding to the non-optimized filtering device LPF (diamond curve 4).

  The result of implementing the air gap AG is shown by the current of the current I after saturation (square curve 7 in FIG. 3c) at the moment when the motor is operated compared to the non-optimized filtering device LPF. This is a slow change.

  FIG. 4 shows an inductive filtering device of the type previously developed by the applicant's company, which includes housings C, YO, CM, CM ′ made of a magnetic material such as iron, and the like. This substantially corresponds to the first winding circuit W1 and the second winding circuit W2.

  The housing has a cylindrical head YO, two closed portions CM and CM ', and an axis C on which winding circuits W1 and W2 are provided.

  The first winding circuit W1 is designed to be inserted in series with the power circuit, and the second winding circuit W2 is short-circuited.

  The second winding circuit W2 has a plurality of turns or is manufactured in the shape of a ring.

  According to a first preferred embodiment shown in FIG. 5, the optimized device LPF has the same essential elements as the non-optimized filtering device LPF, ie a housing C made of magnetic material, YO, CM, CM ′, and a first winding circuit W1 and a second winding circuit W2. It differs in the presence of a central air gap AG of about 0.5 mm to 5 mm that is located substantially in the center of the central core C in the axial direction.

  According to the second preferred embodiment shown in FIG. 6, the optimized device LPF has an axis C having two end air gaps AG1, AG1 ′ between the closed portions CM, CM ′. Have. These air gaps AG and AG 'are preferably about 0.5 mm to 5 mm.

  According to a third preferred embodiment shown in FIGS. 7a and 7b, the optimized device LPF has closed portions CM, CM ′ having annular air gaps AG2, AG2 ′; AG3, AG3 ′, respectively. Have.

  These annular air gaps AG2, AG2 ′; AG3, AG3 ′ are aligned with either the first winding circuit W1 (FIG. 7a) or the second winding circuit W2 (FIG. 7b) in the axial direction. That is, the buses that define them are substantially coupled to the buses that enclose the first winding circuit W1 and the second winding circuit W2.

  The air gap AG in the magnetic circuits C, YO, CM, CM ′ arrives later than the saturation of the magnetic circuits C, YO, CM, CM ′, and is therefore startered by the weakened current level (by the filtering device LPF). DCM, EC electric motor DCM makes it possible to provide longer.

  Thus, the electric motor DCM reaches a higher rotational speed, thereby producing a higher back electromotive force that contributes to the direction of limiting the current I at the moment of saturation.

  In an embodiment of the invention, the second winding circuit W2 is advantageously constituted by a conductive tube concentric with the first winding circuit W1 (eg made from copper or aluminum), It may be arranged outside or inside the winding circuit W1.

This type of structure may result in a filtering device LPF that is simpler to manufacture than a second winding circuit W2 having multiple turns. It will be noted that maintaining a length-to-diameter ratio that is identical to the length-to-diameter ratio of the second winding circuit W2 having multiple turns requires accurate sizing of the tube thickness. N2 and N1 is the number of turns of windings circuit W2 and W1, respectively, if there is a transition from the resistance R for N2 wound up resistor R / N2 ² for one turn having a tube, electrical function of the filtering device the LPF Will not change as a result of the ratio of N1 / N2 characterizing the transformer.

  It will be understood that the present invention is not simply limited to the preferred embodiments described above.

  In particular, the various arrangements of the clearly described air gaps (AG) in the magnetic circuits C, YO, CM, CM 'are merely examples of embodiments.

  In the above description, the air gap AG is an implicit free space between the two parts of the magnetic circuits C, YO, CM, and CM ′.

  Instead, the function of the air gap AG can be obtained by a part that can be saturated in the magnetic circuit C, YO, CM, CM ', which part is saturated either suddenly or progressively. For example, the closed portions CM, CM 'having a portion insufficient for the passage of the entire flow rate will be saturated starting from a central portion that is equivalent to a progressively formed air gap. Saturation can be determined by selecting the thickness of the closed part CM, CM 'by diameter. Similarly, throttling at the core C or external flow return can be used to create a gradual air gap effect due to saturation.

  The invention accordingly encompasses all possible variations of the embodiments within the scope of the following claims.

Claims (10)

A combination (1) of a starter (DCM, EC) and a device for increasing battery voltage (LPF) in an electric starter circuit of an automobile,
The starter (DCM, EC) has an electric motor (DCM) and an electromagnetic contactor (EC),
The battery voltage raising device (LPF) is designed to prevent a drop in battery voltage (Vbat) that occurs after a current surge caused by operating the starter (DCM, EC) in a power circuit. ,
The battery voltage raising device (LPF) is composed of an inductive filtering device (LPF) attached in series with the electric motor (DCM) in the power circuit,
The filtering device includes a cylindrical head (YO), two closed parts (CM, CM ′), and a first winding circuit (W1) designed to be inserted in series around the power circuit. ) And a short circuited second winding circuit (W2) and a magnetic circuit (YO, C, CM) composed of a housing (YO, C) made of a magnetic material having an axis (C) in which the second winding circuit (W2) is disposed. CM ')
The shaft center (C) has at least one air gap (AG; AG1, AG1 ′). The combination of claim 1, wherein the at least one air gap is a central air gap (AG). The combination according to claim 1, characterized in that the at least one air gap has two end air gaps (AG1, AG1 ') between the closed portions (CM, CM'). The combination according to claim 1, characterized in that the closing parts (CM, CM ') each have an annular air gap (AG2, AG2'; AG3, AG3 '). The annular air gap (AG2, AG2 ′; AG3, AG3 ′) is arranged in a line in the axial direction with the first winding circuit (W1) or the second winding circuit (W2). The combination according to claim 4. The combination according to any one of claims 1 to 5, wherein the second winding circuit (W2) is formed of a conductive tube. The combination according to claim 6, wherein the tube is made of copper or aluminum and has a predetermined length-to-diameter ratio and a predetermined thickness. The filtering device (LPF) is inserted into the starter power circuit (DCM, EC) between the positive terminal (B +) of the car battery and the power contact (CP) of the electromagnetic contactor (EC). The combination according to any one of claims 1 to 7, characterized in that. The filtering device (LPF) is inserted in the starter power circuit (DCM, EC) between a power contact (CP) of the electromagnetic contactor (EC) and the electric motor (DCM). The combination according to any one of claims 1 to 7. A starter (DCM, EC) that can be incorporated into the combination (1) according to any one of claims 1 to 9,
The starter characterized in that the filtering device (LPF) included in the combination (1) is fixed on an outer case of the starter (DCM, EC).

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