Diagnosis of the state of an auxiliary battery of a vehicle by means of current pulses

Abstract

The present invention discloses a means of transportation (V), the means of transportation comprising: - an auxiliary battery (BS) electrically powered via a connection to a vehicle network (RB); and - a processor (PR) and a memory (MD), the processor and the memory being configured to perform the following operations when a diagnosis of the auxiliary battery (BS) and its connection is requested: control the generation of at least two consecutive current pulses with a selected profile such that the auxiliary battery (BS) consumes current, and, during each pulse, trigger at least one measurement of the current consumed by the auxiliary battery (BS) and of the voltage at the terminals of the auxiliary battery (BS), then determine an actual internal resistance based on the measured consumed currents and voltages, and then trigger the transmission of a first alarm signal when the actual internal resistance is less than a first selected threshold.

Description

Technical field

[0001] The present invention claims the priority of French application No. 2000166 filed on January 9, 2020, the content (text, drawings and claims) of which is incorporated herein by reference.

[0002] The present invention relates to a vehicle comprising an auxiliary battery for electrically powering an on-board network, and more particularly to the diagnosis of the state of the auxiliary battery of such vehicles themselves. Background art

[0003] Many vehicles include an on-board network that includes electronic (or electrical) equipment that consumes electrical energy. As is known to those skilled in the art, this electrical energy is generally provided by an auxiliary battery of the ultra-low voltage type (for example, 12V, 24V or 48V), or by a DC / DC (or DC / DC) converter (which is powered by a rechargeable battery) in the absence of an alternator or when it is not possible to use the alternator, and the rechargeable battery also supplies electrical energy to the electric drive machine of the powertrain (or GMP).

[0004] The availability of the electrical power of the auxiliary battery is important for driving safety, because this electrical power constitutes the only power source capable of powering the safety functions of the vehicle when the auxiliary battery is correctly connected to the on-board network, and the safety functions (such as steering assistance, braking assistance or route control) are more demanding in terms of electrical power. Therefore, it is necessary to ensure that the state of charge and the state of health of the auxiliary battery are in an optimal state.

[0005] For a vehicle equipped with a starter, the successful starting of the powertrain (or GMP) is so far a necessary and sufficient criterion for enabling the driver to drive safely. In fact, the starter consumes an electric current, and the intensity of this electric current can only be transmitted by an auxiliary battery that is in a very good state and correctly connected. In this case, the sole fact that the GMP can be started constitutes a diagnosis of the state of the auxiliary battery (more precisely, of the available power).

[0006] An electrified vehicle (hybrid or fully electric) does not necessarily have a starter, and the operation of the starter serves to diagnose the state of the auxiliary battery and / or its connection. In addition, an over-discharged or poorly connected auxiliary battery can transmit sufficient power to activate the GMP and allow the vehicle to travel, but this power is not sufficient to power the safety functions of the vehicle. Therefore, the driver of the vehicle can start a driving phase and even subsequent driving phases without knowing that the auxiliary battery and / or its connection cannot meet the requirements for the safety functions of the vehicle.

[0007] Of course, in some all-electric vehicles with GMP, it has been proposed to estimate the state of the auxiliary battery at the start of each journey by switching a resistance on the vehicle electrical network for typically 200 ms to extract a current pulse of typically 100 A from the auxiliary battery. When this extraction is carried out correctly, the auxiliary battery is considered to be in very good condition and is thus capable of meeting the requirements for the safety functions of the vehicle. In the opposite case, the auxiliary battery is considered not to be in good enough condition, and this situation is notified to the driver. This solution can only be implemented before the driving phase because during driving the diagnosis is distorted, on the one hand due to the parallel consumption of other components of the vehicle electrical network, and on the other hand due to the power generated by the DC / DC converter.

[0008] However, in some vehicles, it has been verified that, in terms of safety, it is necessary to determine during the driving phase whether the auxiliary battery of these vehicles is capable of at least meeting the requirements for the safety functions. In addition, when the auxiliary battery is defective during the driving phase, operation in degraded mode is not established.

[0009] Therefore, an object of the present invention is in particular to improve this situation. Summary of the Invention

[0010] To this end, the present invention in particular provides a vehicle, the vehicle comprising:

[0011] - an auxiliary battery, the auxiliary battery being electrically powered via a connection to the vehicle electrical network, and

[0012] - at least one processor and at least one memory, the at least one processor and at least one memory being configured to perform the following operations when a diagnosis of the auxiliary battery and its connections is requested: control the generation of at least two successive current pulses with a selected profile such that the auxiliary battery consumes current, and, during each pulse, trigger at least one measurement of the current consumed by the auxiliary battery and of the voltage at the terminals of the auxiliary battery, then, based on the measured consumed currents and voltages, determine the actual internal resistance, and then, when the actual internal resistance is less than a first selected threshold, trigger the transmission of a first alarm signal.

[0013] Advantageously, the generation of a plurality of successive current pulses makes it possible to know the value of the actual internal resistance with very high precision.

[0014] The vehicle according to the invention may include other features, in particular those that can be used alone or in combination, in particular:

[0015] - The processor and the memory can be configured to perform the following operations: control the generation of five consecutive current pulses having the selected profile;

[0016] - Each current pulse can include: a first part having a duration between 4 ms and 8 ms and an intensity between 60 A and 120 A; and a second part following the first part, the second part having a duration between 4 ms and 8 ms and an intensity between 5 A and 15 A;

[0017] - The processor and the memory can be configured to perform the following operations: for each current pulse, determine an intermediate internal resistance, then multiply these intermediate internal resistances by a first selected weighting coefficient respectively to obtain weighted internal resistances, and then determine the actual internal resistance by performing the sum of these weighted internal resistances divided by the sum of these weighting coefficients;

[0018] - The processor and the memory can be configured to perform the following operations: multiply the voltage measured for each current pulse by a selected weighting coefficient respectively to obtain weighted voltages, and then determine the actual voltage by performing the sum of these weighted voltages divided by the sum of these weighting coefficients;

[0019] - The vehicle can include a circuit breaker installed between the auxiliary battery and the vehicle network and having an active state, wherein the circuit breaker can be opened or closed to prohibit or authorize the passage of current. In this case, the processor and the memory can be configured to perform the following operations when a diagnosis of the auxiliary battery and its connections is requested: control the placement of the circuit breaker to its own active state, then control the opening of the circuit breaker to cause a drop in the voltage of the auxiliary battery, and control the generation of the consecutive current pulses in the case of detecting a difference between the voltage of the auxiliary battery and the voltage of the vehicle network;

[0020] - The processor and the memory can be configured to perform the following operations: control the opening of the circuit breaker by triggering another current pulse provided for the circuit breaker;

[0021] - The vehicle can include a set of electronic components that generate the current having a predefined profile under the command of the processor and the memory.

[0022] The present invention also provides a diagnostic method, which is used on the one hand in a vehicle including an auxiliary battery electrically powered via a connection to a vehicle network, and on the other hand includes steps, wherein when a diagnosis of the auxiliary battery and its connections is requested:

[0023] - Controlling the generation of at least two successive current pulses with a selected profile causes the auxiliary battery to consume current, and during each pulse, at least one measurement of the current consumed by the auxiliary battery and of the voltage at the terminals of the auxiliary battery is triggered,

[0024] - Then, based on the measured consumed currents and voltages, the actual internal resistance is determined, and then

[0025] - Triggering the transmission of a first alarm signal when the actual internal resistance is less than a first selected threshold.

[0026] The invention also provides a computer program product including a set of instructions which, when executed by a processing component, are capable of implementing a diagnostic method of the type described above to diagnose the state of an auxiliary battery electrically powered via a vehicle network connected to a vehicle. Description of the Drawings

[0027] Other features and advantages of the invention will become clearer upon reading the following detailed description of the invention and the drawings, in which:

[0028] - Figure 1 A vehicle according to the invention is schematically and functionally shown, which vehicle includes a hybrid powertrain, a vehicle network, an auxiliary battery, and a diagnostic device,

[0029] - Figure 2 An embodiment of the control logic of the diagnostic device is schematically and functionally shown,

[0030] - Figure 3 An example of the profile of current pulses used for diagnosing the auxiliary battery and its connections is schematically shown in the lower graph, and an example of the curve of the evolution of the voltage (V BS ) of the auxiliary battery over time (t) before, during, and after the generation of the current pulses is schematically shown in the upper graph, and

[0031] - Figure 4 An example of an algorithm for implementing the diagnostic method according to the invention is schematically shown. Detailed Description of the Embodiments

[0032] The object of the invention is in particular to provide a vehicle V according to the invention and an associated diagnostic method, which vehicle includes an auxiliary battery BS electrically powered via a connection to a vehicle network RB and a diagnostic device DD responsible for reliably diagnosing the state of the auxiliary battery BS and its connections.

[0033] In the following, by way of non-limiting example, it is considered that the vehicle V is of the motorized type. The vehicle relates, for example, to an automobile, such asFigure 1 is shown non - restrictively above. However, the present invention is not limited to this type of vehicle. In fact, the present invention relates to any type of vehicle including an auxiliary battery, which is used to electrically power the on - vehicle network. Therefore, the present invention relates not only to land vehicles (including motorcycles therein), but also to boats and aircraft.

[0034] Figure 1 A vehicle V is schematically shown, which vehicle includes a powertrain, an on - vehicle network RB, an auxiliary battery BS and its connections, and a diagnostic device DD.

[0035] The on - vehicle network RB includes electronic (or electrical) equipment that consumes electrical energy. Some of these electronic equipment are used to ensure safety functions (such as steering assistance, braking assistance or route control), and some of these other electronic equipment are used to ensure non - safety functions (such as interior lighting, infotainment, navigation assistance or heating / air conditioning).

[0036] The powertrain here particularly includes a first drive machine MM1, an engine shaft AM, a clutch EM, a second electric drive machine MM2, a gearbox BV, a rechargeable battery BR, and a drive shaft AT. Importantly, it is noted that the shown powertrain is of a hybrid type, but the powertrain can be of a fully electric type and have a power assembly including only at least one electric drive machine, or can be purely thermal.

[0037] Here, the term "drive machine" is understood as a machine configured to provide or recover torque, which torque either alone or as a supplement to another thermal drive machine or electric drive machine causes the vehicle V to move. The thermal drive machine can be, for example, a thermal engine.

[0038] Hereinafter, as a non - restrictive example, it is considered that the first drive machine MM1 is thermal. The first drive machine relates, for example, to a thermal engine. However, the present invention is not limited to this type of first drive machine. In fact, the first drive machine MM1 can be thermal or non - thermal (especially electric).

[0039] This first drive machine MM1 (here a thermal engine) includes a crankshaft (not shown), which crankshaft is fixedly integrated with the engine shaft AM so as to rotate the engine shaft (AM). Additionally, the first drive machine MM1 is used to provide torque to at least a first axle T1 (here a wheel axle) via the clutch EM, the second drive machine MM2 and the gearbox BV.

[0040] For example, the first axle T1 is located at the front of the vehicle V, and is preferably and as shown connected to the drive shaft AT via a differential (here a front differential) D1. However, in a variant, the first axle T1 can be located at the rear of the vehicle V, here designated as T2.

[0041] The clutch EM is responsible for connecting / disconnecting the engine shaft AM (connected to the first drive machine MM1) to / from the second drive machine MM2 under the command of a monitoring calculator CS for monitoring the powertrain, in order to transfer torque based on the torque generated by the first drive machine MM1.

[0042] The second (electric) drive machine MM2 is preferably connected to the rechargeable battery BR via an electrical distribution module MDE installed at the input of the vehicle network RB in order to be supplied with electrical energy, and optionally to supply electrical energy to the rechargeable battery BR. The second (electric) drive machine is also connected here to the output of the clutch EM and to the primary shaft AP of the gearbox BV in order to supply torque to the primary shaft.

[0043] For example, the rechargeable battery BR can be of the low-voltage type (usually e.g. 400V). However, the rechargeable battery can be of the ultra-low-voltage type (usually 48V), or of the medium-voltage type or of the high-voltage type.

[0044] The gearbox BV also includes at least one secondary shaft (not shown), which is used to receive torque via the primary shaft AP in order to transfer the torque to the drive shaft AT to which it is connected, and the drive shaft is indirectly connected to the drive wheels of the vehicle V (here the front drive wheels) via the differential D1.

[0045] The auxiliary battery BS is responsible here for supplying electrical energy to the vehicle network RB via the electrical distribution module MDE. For example, the auxiliary battery BS can be configured in the form of a battery of the ultra-low-voltage type (usually 12V, 24V or 48V).

[0046] Note that the auxiliary battery BS can be connected to the rechargeable battery BR as shown non-limitingly, and is connected to the second drive machine MM2 via a converter CV of the direct current / direct current (or DC / DC) type in order to be rechargeable.

[0047] Also note that, as Figure 1 shown non-limitingly above, the powertrain here includes a starter or an alternating current starter DE, which is connected to the first drive machine MM1 and is responsible for starting the first drive machine (MM1) in order to enable the first drive machine to start. This starting is achieved due to the electrical energy stored, for example and as shown non-limitingly, in the auxiliary battery BS.

[0048] The operation of the auxiliary battery BS, the rechargeable battery BR, and optionally the electrical distribution module MDE can be controlled by a monitoring computer CS, which is responsible for managing the electrical power supply of the vehicle V.

[0049] As mentioned above, the diagnostic device DD is responsible for reliably diagnosing the auxiliary battery BS and its connection status. As Figure 1 shown non - restrictively above, the diagnostic device (DD) includes for this purpose at least one processor PR and at least one memory MD.

[0050] The processor PR can be, for example, a digital signal processor (or DSP (“Digital Signal Processor”)). The processor PR can include an integrated (or printed) circuit, or multiple integrated (or printed) circuits connected by a wired or wireless connection. An integrated (or printed) circuit is understood as any type of device capable of performing at least one electrical or electronic operation. Thus, the processor can relate, for example, to a microcontroller.

[0051] The memory MD is random - access in order to store instructions for implementing at least a part of the diagnostic method described below by the processor PR.

[0052] As Figure 1 and Figure 2 shown non - restrictively above, the processor PR and the memory MD can be part of a control logic LC (or optionally constitute the control logic) for controlling the implementation of the diagnosis. It is understood that, assuming the control logic LC includes at least the processor PR and at least one memory MD, the control logic can be implemented in the form of a combination of an electrical or electronic circuit or component (or “hardware”) and a software module (or “software”).

[0053] Note that, in Figure 1 and Figure 2 the non - restrictive example shown above, the processor PR and the memory MD (and thus here the control logic LC) are integrally part of a housing that is inserted between the auxiliary battery BS and the electrical distribution module MDE. However, in an unshown implementation variant, the processor PR and the memory MD (and thus here the control logic LC) can be part of the monitoring computer CS. In this variant, the diagnostic device DD is thus distributed over at least two devices (the housing and the monitoring computer CS).

[0054] The control logic LC can be directly powered by the auxiliary battery BS, as Figure 1 shown non - restrictively above.

[0055] In a variant, a small accumulator can be provided, which is responsible for supplying electrical energy at least to the control logic LC, or the control logic (LC) can be indirectly powered, for example, by a rechargeable battery BR.

[0056] Whenever a diagnosis of the state of the auxiliary battery BS and its connections is requested by the electronic equipment of the vehicle V (such as the monitoring computer CS), the processor PR and the memory MD intervene. In the presence of such a request, the processor and the memory are first configured to perform the following operations: control the generation of at least two successive current pulses ic with a selected profile such that the auxiliary battery BS consumes current, and, during each pulse ic, trigger at least one measurement of the consumed current ccm and of the voltage V BS at the terminals of the auxiliary battery BS.

[0057] The processor PR and the memory MD are also configured to perform the following operations: determine the actual internal resistance rir based on the measured consumed currents ccm and voltage V BS and then, when this actual internal resistance rir is less than a first selected threshold, trigger the transmission of a first alarm signal. Note that, according to Ohm's law, the resistance is equal to the voltage divided by the current.

[0058] Thanks to this generation of successive current pulses ic, the value of the actual internal resistance rir can thus be very accurately known.

[0059] Note that each measured consumed current ccm can optionally be the average of N direct measurements (where N ≥ 2), and each measured voltage V BS can optionally be the average of N direct measurements. For example, N can be equal to 5 (but this value can take any value greater than or equal to two). But this is not mandatory, as each measured consumed current ccm can be a single direct measurement, and each voltage V BS can be a single direct measurement.

[0060] Also note that the first threshold can be selected to be equal to 5 milliohms. A new, well-charged lead-acid type auxiliary battery has an internal resistance of 5 milliohms at 20 °C. This value of the internal resistance increases at low temperatures and / or with aging and / or in a low state of charge. Thus, the value of the first threshold can optionally be variable according to the temperature and / or state of the auxiliary battery BS.

[0061] For example, the processor PR and the memory MD can be configured to perform the following operations: control the generation of five successive current pulses ic with a selected profile. This number equal to five is only an example, and this number needs to be greater than or equal to two and can thus be less than five (for example, between two and four) or greater than five (for example, equal to six or seven).

[0062] For example, Figure 3 As shown above without limitation, each current pulse ic may comprise: a first portion having a duration between 4 ms and 8 ms and an intensity i2 between 60 A and 120 A; and a second portion following the first portion having a duration between 4 ms and 8 ms and an intensity i1 between 5 A and 15 A. The first portion (or peak) enables determination of whether the battery is able to "respond" in terms of power while being able to carry out at least one measurement of the actual internal resistance rir. The second portion (or plateau) serves to prevent the auxiliary battery BS from polarizing.

[0063] As an illustrative example, the duration of the first portion may be equal to 5 ms and the intensity i2 of the first portion may be equal to 100 A. Also as an illustrative example, the duration of the second portion may be equal to 5 ms and the intensity i1 of the second portion may be equal to 10A.

[0064] In order to implement a profile with two intensities i1 and i2, two switchable resistors can be used: one resistor is able to consume a current with intensity i2 (for example 100 A) and the other resistor is able to consume a current with intensity i1 (for example 10 A). The aim is to achieve that at least one minimized consumed current value (for example 60 A) is consumed from the auxiliary battery BS. Below this minimum value the diagnosis is considered to be not robust (insufficient performance). For example, if the control logic LC detects that the (optionally averaged) measured consumed current ccm does not reach the minimized consumed current value (for example 60 A), the control logic can thus inform the monitoring computer CS of this situation, which thus understands that there is a diagnostic fault, which is interpreted as a defect in the auxiliary battery BS (in terms of the availability of its own power).

[0065] exist Figure 3 1 shows: on the one hand, a lower graph showing an example of a profile of a current pulse ic used for diagnosing an auxiliary battery BS and its connections; and on the other hand, an upper graph showing the voltage V of the auxiliary battery BS before, during and after the generation of the current pulse ic of said lower graph. BS . In this example, before the current pulse ic starts (at t1), the voltage V of the auxiliary battery BS is BS Equal to the voltage of the vehicle network RB (V RB ), the vehicle network voltage is greater than voltage v2 (for example, equal to 14V).

[0066] The generation of the current pulse ic starts at time t1 and ends at time t12. The first part (or peak) of the current pulse ic starts at time t1 and ends at time t6, and (when the auxiliary battery BS is in good condition) causes the voltage V BS The second part (or plateau) of the current pulse ic starts at the instant t7 and ends at the instant t12, and causes the voltage V BS After time t12 (and therefore after current pulse ic), voltage V BS The voltage of the vehicle electrical system RB is increased again to the value V RB Initially, the entire on-board power supply RB is at generator voltage (usually 14V). When the circuit breaker ID of the diagnostic device DD (which is described further below) is opened, the on-board power supply RB maintains 14V and the auxiliary battery BS also maintains 14V (the auxiliary battery is polarized). The voltage V on the auxiliary battery BS side BS Slowly decreases (the auxiliary battery depolarizes). To accelerate the depolarization, a current pulse (or "blank pulse") ic' can be generated, for example. Once the auxiliary battery BS is depolarized, the voltage V BS Less than 14 V, for example 12 V or 13 V. At least two current pulses ic are thereby generated, which cause the auxiliary battery BS to consume a current (for example 100 A) and cause its own voltage V BS The voltage is usually reduced towards 11.5V (V1). BS = E0-rI, where I is the current consumed (here 100A) and E0 is the no-load voltage. Next, because the current extraction is small (V BS =E0-rI, where I = 10A), voltage V BS Then, the voltage V BS Increase again to the no-load voltage E0.

[0067] Note that the processor PR and the memory MD may be configured to perform the following operations: for each current pulse ic determine the intermediate internal resistance rii (which optionally comes from, for example, Figure 3 Direct measurements of ccm and V are performed at times t2 to t6 BS The processor PR and the memory MD may be configured to perform the following operations: determine the actual internal resistance rir by dividing the sum of these weighted internal resistances rip by the sum of the first weighting coefficients. Thus, in the case of five consecutive current pulses ic, there is

[0068] rir = (rii1*a1 + rii2*a2 + rii3*a3 + rii4*a4 + rii5*a5) / (a1 + a2 + a3 + a4 + a5).

[0069] A pre-defined mapping based on the state of the actual internal resistance rir and the actual voltage vr (derived from measurements, which is described in more detail below) can be used to determine whether the actual state of the auxiliary battery BS and its connections is good enough to simultaneously allow driving and power supply for all safety functions of the vehicle V, or whether this state allows driving and power supply for only some of the safety functions of the vehicle V, or whether this state only allows driving.

[0070] For example, if the auxiliary battery BS and / or its connections are considered unable to deliver the minimum safety power, the driver is warned of this situation by the first warning signal and can continue driving (so there is service continuity). Conversely, some functions of the vehicle V can be restricted (or degraded) to ensure driving safety. This actually improves driving safety and the failure detection percentage. This advantage is particularly useful in the case of fully electric safety functions (such as fully electric brake assist) and in the context of a combination of multiple safety functions in the case of automated (or autonomous) driving.

[0071] The processor PR and the memory MD can be configured to perform the following operations: multiplying the voltage V measured for each current pulse ic (which optionally comes from the average value of N voltages derived from direct measurements V performed, for example, from time t2 to t6 as shown in BS (which is optionally from direct measurements V performed from time t2 to t6 as shown in Figure 3 ) by a second selected weighting coefficient to obtain a weighted voltage vp. Next, the processor PR and the memory MD can be configured to perform the following operations: determining the actual voltage vr by performing the sum of these weighted voltages vp divided by the sum of the second weighting coefficients. Thus, in the presence of five consecutive current pulses ic, there is BS vr = (V

[0072] *a1’ + V BS1 *a2’ + V BS2 *a3’ + V BS3 *a4’ + V BS4 *a5’ + V BS5 *a5’) / (a1’ + a2’ + a3’ + a4’ + a5’).

[0073] It is also noted that the current pulse ic can be provided by an optional circuit breaker ID included in the converter CV or the diagnostic device DD under the command of the processor PR and the memory MD, as shown in Figure 1It is generated as shown non - restrictively above. The optional circuit breaker is installed in series between the auxiliary battery BS and the vehicle network RB (more precisely here between the auxiliary battery BS and the electrical distribution module MDE).

[0074] When the converter CV is used, the converter operates in a so - called "boost" (or step - up) mode to generate the current pulse ic. However, this solution can only be implemented during specific life stages (usually when safety functions are not requested (e.g., at low speeds)), because this solution results in disconnecting the generator from the vehicle network RB (the vehicle network locally becomes a consumer).

[0075] During the driving phase, the diagnosis of the auxiliary battery BS and its connections can detect failures of the auxiliary battery BS and / or its connections (e.g., conventional faults such as open circuits, short circuits or disconnections after vibrations or shocks when passing over potholes or speed bumps).

[0076] When the converter CV is in boost mode, the converter generates successive current pulses ic, and the energy of these successive current pulses (ic) needs to enter a consumer (usually a rechargeable battery BR). But if the rechargeable battery (BR) is overcharged and / or over - cooled (and thus unable to consume this energy), the processor PR and the memory MD can trigger the activation of an electrical consumer (such as an electric drive machine, an air - conditioning compressor or a heater) powered by the rechargeable battery BR).

[0077] The optional circuit breaker ID has an active state in which the circuit breaker can be opened to prohibit the passage of current, or properly closed to authorize the passage of current. The circuit breaker also has a de - activated state in which the circuit breaker permanently authorizes the passage of current between the auxiliary battery BS and the vehicle network RB without a direction - of - passage condition (and thus in both directions). When the diagnostic device DD is not in the diagnostic phase, the de - activated state is the default state of the circuit breaker ID.

[0078] In other words, when in the activated closed state as well as when in the de - activated state, the circuit breaker ID behaves as if it has a very low value (usually in the order of milliohms) of resistance, while when in the activated open state, the circuit breaker ID behaves as an ideal diode.

[0079] As an illustrative example, the circuit breaker ID may include at least one optionally n-type enhanced (or nMOS) electronic power component (such as a MOSFET (“Metal Oxide Semiconductor Field Effect Transistor” - field effect transistor with an insulated gate) and a (optionally Zener type) diode assembled in parallel between the auxiliary battery BS and the vehicle network RB. In a variant, the circuit breaker ID may include only one or more nMOS type electronic power components.

[0080] When the diagnosis of the state of the auxiliary battery BS and its connections is requested by the electronic equipment (such as the monitoring computer CS) of the vehicle V, the processor PR and the memory MD are configured to perform the following operations: control the placement of the circuit breaker ID to its activated state (when the circuit breaker is in its deactivated state), and then, control the opening of the circuit breaker to cause a decrease in the voltage V BS of the auxiliary battery BS (and thus cause the depolarization of the auxiliary battery).

[0081] This decrease is implemented because the auxiliary battery BS may be in the following stage: the auxiliary battery no longer accepts charging due to the balance of its voltage V BS with the voltage V RB (and thus with the voltage generated here by the DC / DC converter CV) and thus there is no voltage dip, and it is impossible to know whether the circuit breaker ID has been opened because no current passes from the vehicle network RB towards the auxiliary battery BS.

[0082] Then, when the processor PR and the memory MD detect a difference dv between the voltage V BS and the voltage V RB , the processor and the memory control the generation of successive current pulses ic.

[0083] Due to the difference dv between the voltage V BS and the voltage V RB , it is certain that the auxiliary battery BS is effectively isolated from the vehicle network RB (and thus from the DC / DC converter CV), while allowing an optional current call in an emergency situation, and thus the auxiliary battery can be tested independently of the vehicle network RB and the DC / DC converter CV in order to be able to obtain a reliable diagnosis of the current state of the auxiliary battery and the connection state of the auxiliary battery.

[0084] Note that after the circuit breaker ID is opened, in the absence of a difference between the voltage V BS and the voltage V RBIn the case of a difference dv, the diagnostic device DD determines that there is a problem and thus alerts the monitoring computer CS, for example, by setting the diagnostic parameter to a specific value.

[0085] For example, the processor PR and the memory MD can be configured to perform the following operations: control the opening of the circuit breaker ID by triggering a current pulse (or blank pulse) ic' supplied to the circuit breaker (ID). The current pulse (ic') can have, for example, a duration of less than 10 ms and an intensity greater than 10 A. This very short and high-intensity current pulse ic' causes the current to flow towards the ground and thus accelerates depolarization. As an example, the above-mentioned duration can be selected to be equal to 5 ms and the above-mentioned intensity can be selected to be equal to 100 A.

[0086] It is also noted that, as Figure 1 shown non-limitingly above, the vehicle V can include a set of electronic components EC, the set of electronic components being configured to generate a current pulse ic under the command of the processor PR and the memory MD. As shown in the figure, the set EC can be part of a housing that includes the circuit breaker ID and the control logic LC (which has the processor PR and the memory MD). However, this is not necessary. In fact, the set can be outside the housing but connected to the control logic LC.

[0087] As an illustrative example, the set of electronic components EC can include two sub-branches that are assembled in parallel via a power resistor (preferably of the energy type) between the ground and the circuit for connecting the auxiliary battery BS to the vehicle network RB. In this case, the first sub-branch can include at least one electronic power component (for example, optionally an n-type enhancement MOSFET (or nMOS)) and a diode (optionally of the Zener type) assembled in parallel. For its part, the second sub-branch can include a power resistor (preferably of the energy type) assembled in series with at least one electronic power component (for example, optionally an n-type enhancement MOSFET (or nMOS)), the at least one electronic power component being assembled in parallel with a diode (optionally of the Zener type).

[0088] It is also noted that, as Figure 2As shown non - restrictively above, the control logic LC (which can be distributed) can also include a mass memory MM (as a supplement to its own random access memory MD and processor PR), which is especially used to store the measured internal resistance, the measured voltage, and the intermediate data involved in all these calculations and processes. Additionally, the control logic LC can also include an input interface IE, which is used to at least receive the value of the measured internal resistance, the value of the measured voltage, and the value of the diagnostic request (from the monitoring computer CS) to optionally use these values in calculations or processes after shaping and / or demodulating and / or amplifying the values in a manner known per se by means of a digital signal processor PR'. Furthermore, the control logic LC can also include an output interface IS, which is especially used to transmit commands or controls (at least for the circuit breaker ID and the assembly EC, or for the converter CV) and diagnostic results (at least for the monitoring computer CS).

[0089] The present invention can also be regarded in the form of a diagnostic method, which is used to be implemented in a vehicle V. This diagnostic method can be implemented at least partially by a diagnostic device DD.

[0090] This diagnostic method includes steps 10 - 140, wherein, when the diagnosis of the auxiliary battery BS and its connections is requested, the generation of at least two current pulses ic with a selected profile in succession is controlled such that the auxiliary battery BS consumes current, and during each pulse ic, at least one measurement of the current consumed by the auxiliary battery BS and of the voltage V BS at the terminals of the auxiliary battery BS is triggered, and then, based on the measured consumed currents and the voltage V BS the actual internal resistance rir is determined, and then, when the actual internal resistance rir is less than a first selected threshold, the transmission of a first alarm signal is triggered.

[0091] Figure 4 An example of an algorithm for implementing the diagnostic method according to the present invention is schematically shown above.

[0092] The algorithm includes a sub - step 10, wherein a diagnostic request for the auxiliary battery BS and its connections is received.

[0093] Then, in sub - step 20, the placement of the circuit breaker ID in its self - activation state is triggered, and then the opening of the circuit breaker is triggered.

[0094] Then, in sub - step 30, it is determined whether there is a difference dv between the voltage of the auxiliary battery BS and the voltage of the vehicle network RB.

[0095] In the absence of a difference dv, a delay of duration dt can optionally be triggered in sub-step 40. Then, in sub-step 50, it can be determined whether there is a difference dv between the voltage of the auxiliary battery BS and the voltage of the vehicle network RB and whether the duration dt has expired.

[0096] In the presence of a difference dv, if the duration dt has not expired, sub-step 70 is executed. Conversely, if the duration dt has expired and there is no difference dv, in sub-step 60 the diagnostic parameter is set to a specific value indicating a problem.

[0097] Conversely, in the presence of a difference dv, in sub-step 70 the generation of at least two successive current pulses ic with a selected profile is triggered such that the auxiliary battery BS consumes a current ccm, and, during each pulse ic, a measurement is triggered for the consumed current ccm consumed by the auxiliary battery BS and for the voltage V BS at the terminals of the auxiliary battery BS.

[0098] Then, in sub-step 80, based on the measured consumed currents ccm and the voltage V BS the actual internal resistance rir is determined.

[0099] Then, in sub-step 90, the state of the auxiliary battery BS and its connections is determined.

[0100] If the auxiliary battery BS and its connections are diagnosed as being in good condition (the actual internal resistance rir is greater than a first selected threshold), nothing happens in sub-step 100 except that the uncertainty counter related to the state of the auxiliary battery BS is reset to zero.

[0101] If the auxiliary battery BS and its connections are diagnosed as being uncertain, it is not possible to decide on the state of the auxiliary battery and its connections. In fact, the auxiliary battery BS can be, for example, discharged, cold or treated with copper sulfate. In this case, in sub-step 110 the uncertainty counter is incremented and the next diagnosis is awaited to confirm whether the state of the auxiliary battery BS and its connections has evolved. When the uncertainty counter reaches a predefined value (for example equal to 10) in sub-step 120, this means that the state of the auxiliary battery BS and its connections has not improved and therefore in sub-step 130 a second alarm signal is transmitted to inform the driver of the vehicle V that it is necessary to intervene.

[0102] If the auxiliary battery BS and its connections are diagnosed as being in a poor state (actual internal resistance rir less than a first selected threshold), this means that the state of the auxiliary battery BS and its connections does not guarantee the minimum operating voltage of the safety electronic equipment, and therefore a first alarm signal is transmitted in sub-step 140 to inform the driver of the vehicle V of the need to stop as quickly as possible. To ensure that the driver stops completely safely, the stop of the power-interruptible electronic equipment can be controlled so as to ensure the maximum power availability of the converter CV for powering the safety electronic equipment and the standard (non-safety) electronic equipment.

[0103] It is also noted that the present invention also relates to a computer program product (or computer program), the computer program product comprising a set of instructions which, when executed by a processing component of the electronic circuit (or hardware) type (such as the processor PR), are capable of implementing the diagnostic method described above to diagnose the state of the auxiliary battery BS of the vehicle V and the state of the connections of this auxiliary battery BS.

[0104] It is also noted that one or more sub-steps of the steps of the diagnostic method can be executed by different constituent elements. Thus, the diagnostic method can be implemented by a plurality of digital signal processors, random access memories, mass memories, input interfaces, output interfaces.

Claims

1. A vehicle (V), the vehicle comprising an auxiliary battery (BS) electrically powered via a connection to a vehicle network (RB). Characterized in that the vehicle further comprises at least one processor (PR) and at least one memory (MD), the at least one processor and at least one memory being configured to perform the following operations when requested for a diagnosis of the auxiliary battery (BS) and its connection: control the generation of at least two consecutive current pulses having a selected profile such that the auxiliary battery (BS) consumes current, and, during each current pulse, trigger at least one measurement of the current consumed by the auxiliary battery (BS) and of the voltage at the terminals of the auxiliary battery (BS), then, based on the measured consumed currents and voltages, determine the actual internal resistance, and then, when the actual internal resistance is less than a first selected threshold, trigger the transmission of a first alarm signal, wherein each current pulse comprises: a first part having a duration between 4 ms and 8 ms and an intensity between 60 A and 120 A; and a second part following the first part, the second part having a duration between 4 ms and 8 ms and an intensity between 5 A and 15 A.

2. The vehicle according to claim 1, Characterized in that the processor (PR) and the memory (MD) are configured to perform the following operation: control the generation of five consecutive current pulses having the selected profile.

3. The vehicle according to claim 1 or 2, Characterized in that the processor (PR) and the memory (MD) are configured to perform the following operations: determine an intermediate internal resistance for each current pulse, then multiply these intermediate internal resistances by a first selected weighting factor respectively to obtain weighted internal resistances, and then determine the actual internal resistance by performing the sum of the weighted internal resistances divided by the sum of the weighting factors.

4. The vehicle according to claim 1 or 2, Characterized in that the processor (PR) and the memory (MD) are configured to perform the following operations: multiply the voltage measured for each current pulse by a selected weighting factor respectively to obtain weighted voltages, and then determine the actual voltage by performing the sum of the weighted voltages divided by the sum of the weighting factors.

5. The vehicle according to claim 1 or 2, Characterized in that The vehicle includes a circuit breaker (ID) installed between the auxiliary battery (BS) and the vehicle network (RB) and having an active state, wherein the circuit breaker can be opened or closed to prohibit or authorize the passage of current, and the processor (PR) and the memory (MD) are configured to perform the following operations when a diagnosis of the auxiliary battery (BS) and its connections is requested: control the placement of the circuit breaker (ID) to its active state, then control the opening of the circuit breaker to cause a drop in the voltage of the auxiliary battery (BS), and control the generation of successive current pulses when a difference between the voltage of the auxiliary battery (BS) and the voltage of the vehicle network (RB) is detected.

6. The vehicle according to claim 5, characterized in that the processor (PR) and the memory (MD) are configured to perform the following operation: control the opening of the circuit breaker (ID) by triggering another current pulse provided for the circuit breaker (ID).

7. The vehicle according to any one of claims 1, 2, and 6, characterized in that the vehicle includes a set of electronic components (EC) that generate the current having a predefined profile under the command of the processor (PR) and the memory (MD).

8. A diagnostic method for a vehicle (V) that includes an auxiliary battery (BS) electrically powered via connection to a vehicle network (RB), characterized in that the diagnostic method includes steps (10 - 140), wherein when a diagnosis of the auxiliary battery (BS) and its connections is requested, control the generation of at least two successive current pulses having a selected profile such that the auxiliary battery (BS) consumes current, and during each current pulse trigger at least one measurement of the current consumed by the auxiliary battery (BS) and of the voltage at the terminals of the auxiliary battery (BS), then determine the actual internal resistance based on the measured consumed currents and voltages, and then trigger the transmission of a first alarm signal when the actual internal resistance is less than a first selected threshold, wherein each current pulse includes: a first part having a duration between 4 ms and 8 ms and an intensity between 60 A and 120 A; and a second part following the first part having a duration between 4 ms and 8 ms and an intensity between 5 A and 15 A.

9. A computer program product that includes a set of instructions that, when executed by a processing component, can implement the diagnostic method according to claim 8 to diagnose the state of an auxiliary battery (BS) electrically powered via connection to a vehicle network (RB) of a vehicle (V).

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